Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * mm/mmap.c |
| 3 | * |
| 4 | * Written by obz. |
| 5 | * |
Alan Cox | 046c688 | 2009-01-05 14:06:29 +0000 | [diff] [blame] | 6 | * Address space accounting code <alan@lxorguk.ukuu.org.uk> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 7 | */ |
| 8 | |
| 9 | #include <linux/slab.h> |
Alexey Dobriyan | 4af3c9c | 2007-10-16 23:29:23 -0700 | [diff] [blame] | 10 | #include <linux/backing-dev.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 11 | #include <linux/mm.h> |
| 12 | #include <linux/shm.h> |
| 13 | #include <linux/mman.h> |
| 14 | #include <linux/pagemap.h> |
| 15 | #include <linux/swap.h> |
| 16 | #include <linux/syscalls.h> |
Randy.Dunlap | c59ede7 | 2006-01-11 12:17:46 -0800 | [diff] [blame] | 17 | #include <linux/capability.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 18 | #include <linux/init.h> |
| 19 | #include <linux/file.h> |
| 20 | #include <linux/fs.h> |
| 21 | #include <linux/personality.h> |
| 22 | #include <linux/security.h> |
| 23 | #include <linux/hugetlb.h> |
| 24 | #include <linux/profile.h> |
Paul Gortmaker | b95f1b31 | 2011-10-16 02:01:52 -0400 | [diff] [blame] | 25 | #include <linux/export.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 26 | #include <linux/mount.h> |
| 27 | #include <linux/mempolicy.h> |
| 28 | #include <linux/rmap.h> |
Andrea Arcangeli | cddb8a5 | 2008-07-28 15:46:29 -0700 | [diff] [blame] | 29 | #include <linux/mmu_notifier.h> |
Ingo Molnar | cdd6c48 | 2009-09-21 12:02:48 +0200 | [diff] [blame] | 30 | #include <linux/perf_event.h> |
Al Viro | 120a795 | 2010-10-30 02:54:44 -0400 | [diff] [blame] | 31 | #include <linux/audit.h> |
Andrea Arcangeli | b15d00b | 2011-01-13 15:46:59 -0800 | [diff] [blame] | 32 | #include <linux/khugepaged.h> |
Srikar Dronamraju | 2b14449 | 2012-02-09 14:56:42 +0530 | [diff] [blame] | 33 | #include <linux/uprobes.h> |
Michel Lespinasse | d373718 | 2012-12-11 16:01:38 -0800 | [diff] [blame] | 34 | #include <linux/rbtree_augmented.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | |
| 36 | #include <asm/uaccess.h> |
| 37 | #include <asm/cacheflush.h> |
| 38 | #include <asm/tlb.h> |
Jeremy Fitzhardinge | d6dd61c | 2007-05-02 19:27:14 +0200 | [diff] [blame] | 39 | #include <asm/mmu_context.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 40 | |
Jan Beulich | 42b7772 | 2008-07-23 21:27:10 -0700 | [diff] [blame] | 41 | #include "internal.h" |
| 42 | |
Kirill Korotaev | 3a45975 | 2006-09-07 14:17:04 +0400 | [diff] [blame] | 43 | #ifndef arch_mmap_check |
| 44 | #define arch_mmap_check(addr, len, flags) (0) |
| 45 | #endif |
| 46 | |
Martin Schwidefsky | 08e7d9b | 2008-02-04 22:29:16 -0800 | [diff] [blame] | 47 | #ifndef arch_rebalance_pgtables |
| 48 | #define arch_rebalance_pgtables(addr, len) (addr) |
| 49 | #endif |
| 50 | |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 51 | static void unmap_region(struct mm_struct *mm, |
| 52 | struct vm_area_struct *vma, struct vm_area_struct *prev, |
| 53 | unsigned long start, unsigned long end); |
| 54 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 55 | /* description of effects of mapping type and prot in current implementation. |
| 56 | * this is due to the limited x86 page protection hardware. The expected |
| 57 | * behavior is in parens: |
| 58 | * |
| 59 | * map_type prot |
| 60 | * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC |
| 61 | * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes |
| 62 | * w: (no) no w: (no) no w: (yes) yes w: (no) no |
| 63 | * x: (no) no x: (no) yes x: (no) yes x: (yes) yes |
| 64 | * |
| 65 | * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes |
| 66 | * w: (no) no w: (no) no w: (copy) copy w: (no) no |
| 67 | * x: (no) no x: (no) yes x: (no) yes x: (yes) yes |
| 68 | * |
| 69 | */ |
| 70 | pgprot_t protection_map[16] = { |
| 71 | __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111, |
| 72 | __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111 |
| 73 | }; |
| 74 | |
Hugh Dickins | 804af2c | 2006-07-26 21:39:49 +0100 | [diff] [blame] | 75 | pgprot_t vm_get_page_prot(unsigned long vm_flags) |
| 76 | { |
Dave Kleikamp | b845f31 | 2008-07-08 00:28:51 +1000 | [diff] [blame] | 77 | return __pgprot(pgprot_val(protection_map[vm_flags & |
| 78 | (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) | |
| 79 | pgprot_val(arch_vm_get_page_prot(vm_flags))); |
Hugh Dickins | 804af2c | 2006-07-26 21:39:49 +0100 | [diff] [blame] | 80 | } |
| 81 | EXPORT_SYMBOL(vm_get_page_prot); |
| 82 | |
Shaohua Li | 34679d7 | 2011-05-24 17:11:18 -0700 | [diff] [blame] | 83 | int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS; /* heuristic overcommit */ |
| 84 | int sysctl_overcommit_ratio __read_mostly = 50; /* default is 50% */ |
Christoph Lameter | c3d8c14 | 2005-09-06 15:16:33 -0700 | [diff] [blame] | 85 | int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT; |
Shaohua Li | 34679d7 | 2011-05-24 17:11:18 -0700 | [diff] [blame] | 86 | /* |
| 87 | * Make sure vm_committed_as in one cacheline and not cacheline shared with |
| 88 | * other variables. It can be updated by several CPUs frequently. |
| 89 | */ |
| 90 | struct percpu_counter vm_committed_as ____cacheline_aligned_in_smp; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 91 | |
| 92 | /* |
K. Y. Srinivasan | 997071b | 2012-11-15 14:34:42 -0800 | [diff] [blame] | 93 | * The global memory commitment made in the system can be a metric |
| 94 | * that can be used to drive ballooning decisions when Linux is hosted |
| 95 | * as a guest. On Hyper-V, the host implements a policy engine for dynamically |
| 96 | * balancing memory across competing virtual machines that are hosted. |
| 97 | * Several metrics drive this policy engine including the guest reported |
| 98 | * memory commitment. |
| 99 | */ |
| 100 | unsigned long vm_memory_committed(void) |
| 101 | { |
| 102 | return percpu_counter_read_positive(&vm_committed_as); |
| 103 | } |
| 104 | EXPORT_SYMBOL_GPL(vm_memory_committed); |
| 105 | |
| 106 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 107 | * Check that a process has enough memory to allocate a new virtual |
| 108 | * mapping. 0 means there is enough memory for the allocation to |
| 109 | * succeed and -ENOMEM implies there is not. |
| 110 | * |
| 111 | * We currently support three overcommit policies, which are set via the |
| 112 | * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting |
| 113 | * |
| 114 | * Strict overcommit modes added 2002 Feb 26 by Alan Cox. |
| 115 | * Additional code 2002 Jul 20 by Robert Love. |
| 116 | * |
| 117 | * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise. |
| 118 | * |
| 119 | * Note this is a helper function intended to be used by LSMs which |
| 120 | * wish to use this logic. |
| 121 | */ |
Alan Cox | 34b4e4a | 2007-08-22 14:01:28 -0700 | [diff] [blame] | 122 | int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 123 | { |
| 124 | unsigned long free, allowed; |
| 125 | |
| 126 | vm_acct_memory(pages); |
| 127 | |
| 128 | /* |
| 129 | * Sometimes we want to use more memory than we have |
| 130 | */ |
| 131 | if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS) |
| 132 | return 0; |
| 133 | |
| 134 | if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { |
Dmitry Fink | c15bef3 | 2011-07-25 17:12:19 -0700 | [diff] [blame] | 135 | free = global_page_state(NR_FREE_PAGES); |
| 136 | free += global_page_state(NR_FILE_PAGES); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 137 | |
Dmitry Fink | c15bef3 | 2011-07-25 17:12:19 -0700 | [diff] [blame] | 138 | /* |
| 139 | * shmem pages shouldn't be counted as free in this |
| 140 | * case, they can't be purged, only swapped out, and |
| 141 | * that won't affect the overall amount of available |
| 142 | * memory in the system. |
| 143 | */ |
| 144 | free -= global_page_state(NR_SHMEM); |
| 145 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 146 | free += nr_swap_pages; |
| 147 | |
| 148 | /* |
| 149 | * Any slabs which are created with the |
| 150 | * SLAB_RECLAIM_ACCOUNT flag claim to have contents |
| 151 | * which are reclaimable, under pressure. The dentry |
| 152 | * cache and most inode caches should fall into this |
| 153 | */ |
Christoph Lameter | 972d1a7 | 2006-09-25 23:31:51 -0700 | [diff] [blame] | 154 | free += global_page_state(NR_SLAB_RECLAIMABLE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 155 | |
| 156 | /* |
Dmitry Fink | c15bef3 | 2011-07-25 17:12:19 -0700 | [diff] [blame] | 157 | * Leave reserved pages. The pages are not for anonymous pages. |
| 158 | */ |
| 159 | if (free <= totalreserve_pages) |
| 160 | goto error; |
| 161 | else |
| 162 | free -= totalreserve_pages; |
| 163 | |
| 164 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 165 | * Leave the last 3% for root |
| 166 | */ |
| 167 | if (!cap_sys_admin) |
| 168 | free -= free / 32; |
| 169 | |
| 170 | if (free > pages) |
| 171 | return 0; |
| 172 | |
Hideo AOKI | 6d9f783 | 2006-04-10 22:53:00 -0700 | [diff] [blame] | 173 | goto error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 174 | } |
| 175 | |
| 176 | allowed = (totalram_pages - hugetlb_total_pages()) |
| 177 | * sysctl_overcommit_ratio / 100; |
| 178 | /* |
| 179 | * Leave the last 3% for root |
| 180 | */ |
| 181 | if (!cap_sys_admin) |
| 182 | allowed -= allowed / 32; |
| 183 | allowed += total_swap_pages; |
| 184 | |
| 185 | /* Don't let a single process grow too big: |
| 186 | leave 3% of the size of this process for other processes */ |
Alan Cox | 731572d | 2008-10-29 14:01:20 -0700 | [diff] [blame] | 187 | if (mm) |
| 188 | allowed -= mm->total_vm / 32; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 189 | |
KOSAKI Motohiro | 00a62ce | 2009-04-30 15:08:51 -0700 | [diff] [blame] | 190 | if (percpu_counter_read_positive(&vm_committed_as) < allowed) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 191 | return 0; |
Hideo AOKI | 6d9f783 | 2006-04-10 22:53:00 -0700 | [diff] [blame] | 192 | error: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 193 | vm_unacct_memory(pages); |
| 194 | |
| 195 | return -ENOMEM; |
| 196 | } |
| 197 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 198 | /* |
Peter Zijlstra | 3d48ae4 | 2011-05-24 17:12:06 -0700 | [diff] [blame] | 199 | * Requires inode->i_mapping->i_mmap_mutex |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 200 | */ |
| 201 | static void __remove_shared_vm_struct(struct vm_area_struct *vma, |
| 202 | struct file *file, struct address_space *mapping) |
| 203 | { |
| 204 | if (vma->vm_flags & VM_DENYWRITE) |
Josef "Jeff" Sipek | d3ac7f8 | 2006-12-08 02:36:44 -0800 | [diff] [blame] | 205 | atomic_inc(&file->f_path.dentry->d_inode->i_writecount); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 206 | if (vma->vm_flags & VM_SHARED) |
| 207 | mapping->i_mmap_writable--; |
| 208 | |
| 209 | flush_dcache_mmap_lock(mapping); |
| 210 | if (unlikely(vma->vm_flags & VM_NONLINEAR)) |
Michel Lespinasse | 6b2dbba | 2012-10-08 16:31:25 -0700 | [diff] [blame] | 211 | list_del_init(&vma->shared.nonlinear); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 212 | else |
Michel Lespinasse | 6b2dbba | 2012-10-08 16:31:25 -0700 | [diff] [blame] | 213 | vma_interval_tree_remove(vma, &mapping->i_mmap); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 214 | flush_dcache_mmap_unlock(mapping); |
| 215 | } |
| 216 | |
| 217 | /* |
Michel Lespinasse | 6b2dbba | 2012-10-08 16:31:25 -0700 | [diff] [blame] | 218 | * Unlink a file-based vm structure from its interval tree, to hide |
Hugh Dickins | a8fb561 | 2005-10-29 18:15:57 -0700 | [diff] [blame] | 219 | * vma from rmap and vmtruncate before freeing its page tables. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 220 | */ |
Hugh Dickins | a8fb561 | 2005-10-29 18:15:57 -0700 | [diff] [blame] | 221 | void unlink_file_vma(struct vm_area_struct *vma) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 222 | { |
| 223 | struct file *file = vma->vm_file; |
| 224 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 225 | if (file) { |
| 226 | struct address_space *mapping = file->f_mapping; |
Peter Zijlstra | 3d48ae4 | 2011-05-24 17:12:06 -0700 | [diff] [blame] | 227 | mutex_lock(&mapping->i_mmap_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 228 | __remove_shared_vm_struct(vma, file, mapping); |
Peter Zijlstra | 3d48ae4 | 2011-05-24 17:12:06 -0700 | [diff] [blame] | 229 | mutex_unlock(&mapping->i_mmap_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 230 | } |
Hugh Dickins | a8fb561 | 2005-10-29 18:15:57 -0700 | [diff] [blame] | 231 | } |
| 232 | |
| 233 | /* |
| 234 | * Close a vm structure and free it, returning the next. |
| 235 | */ |
| 236 | static struct vm_area_struct *remove_vma(struct vm_area_struct *vma) |
| 237 | { |
| 238 | struct vm_area_struct *next = vma->vm_next; |
| 239 | |
Hugh Dickins | a8fb561 | 2005-10-29 18:15:57 -0700 | [diff] [blame] | 240 | might_sleep(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 241 | if (vma->vm_ops && vma->vm_ops->close) |
| 242 | vma->vm_ops->close(vma); |
Konstantin Khlebnikov | e9714ac | 2012-10-08 16:28:54 -0700 | [diff] [blame] | 243 | if (vma->vm_file) |
Hugh Dickins | a8fb561 | 2005-10-29 18:15:57 -0700 | [diff] [blame] | 244 | fput(vma->vm_file); |
Lee Schermerhorn | f0be3d3 | 2008-04-28 02:13:08 -0700 | [diff] [blame] | 245 | mpol_put(vma_policy(vma)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 246 | kmem_cache_free(vm_area_cachep, vma); |
Hugh Dickins | a8fb561 | 2005-10-29 18:15:57 -0700 | [diff] [blame] | 247 | return next; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 248 | } |
| 249 | |
Linus Torvalds | e4eb1ff | 2012-04-20 15:35:40 -0700 | [diff] [blame] | 250 | static unsigned long do_brk(unsigned long addr, unsigned long len); |
| 251 | |
Heiko Carstens | 6a6160a | 2009-01-14 14:14:15 +0100 | [diff] [blame] | 252 | SYSCALL_DEFINE1(brk, unsigned long, brk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 253 | { |
| 254 | unsigned long rlim, retval; |
| 255 | unsigned long newbrk, oldbrk; |
| 256 | struct mm_struct *mm = current->mm; |
Jiri Kosina | a5b4592 | 2008-06-05 22:46:05 -0700 | [diff] [blame] | 257 | unsigned long min_brk; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 258 | |
| 259 | down_write(&mm->mmap_sem); |
| 260 | |
Jiri Kosina | a5b4592 | 2008-06-05 22:46:05 -0700 | [diff] [blame] | 261 | #ifdef CONFIG_COMPAT_BRK |
Jiri Kosina | 5520e89 | 2011-01-13 15:47:23 -0800 | [diff] [blame] | 262 | /* |
| 263 | * CONFIG_COMPAT_BRK can still be overridden by setting |
| 264 | * randomize_va_space to 2, which will still cause mm->start_brk |
| 265 | * to be arbitrarily shifted |
| 266 | */ |
Jiri Kosina | 4471a67 | 2011-04-14 15:22:09 -0700 | [diff] [blame] | 267 | if (current->brk_randomized) |
Jiri Kosina | 5520e89 | 2011-01-13 15:47:23 -0800 | [diff] [blame] | 268 | min_brk = mm->start_brk; |
| 269 | else |
| 270 | min_brk = mm->end_data; |
Jiri Kosina | a5b4592 | 2008-06-05 22:46:05 -0700 | [diff] [blame] | 271 | #else |
| 272 | min_brk = mm->start_brk; |
| 273 | #endif |
| 274 | if (brk < min_brk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 275 | goto out; |
Ram Gupta | 1e62419 | 2006-04-10 22:52:57 -0700 | [diff] [blame] | 276 | |
| 277 | /* |
| 278 | * Check against rlimit here. If this check is done later after the test |
| 279 | * of oldbrk with newbrk then it can escape the test and let the data |
| 280 | * segment grow beyond its set limit the in case where the limit is |
| 281 | * not page aligned -Ram Gupta |
| 282 | */ |
Jiri Slaby | 59e99e5 | 2010-03-05 13:41:44 -0800 | [diff] [blame] | 283 | rlim = rlimit(RLIMIT_DATA); |
Jiri Kosina | c1d171a | 2008-01-30 13:30:40 +0100 | [diff] [blame] | 284 | if (rlim < RLIM_INFINITY && (brk - mm->start_brk) + |
| 285 | (mm->end_data - mm->start_data) > rlim) |
Ram Gupta | 1e62419 | 2006-04-10 22:52:57 -0700 | [diff] [blame] | 286 | goto out; |
| 287 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 288 | newbrk = PAGE_ALIGN(brk); |
| 289 | oldbrk = PAGE_ALIGN(mm->brk); |
| 290 | if (oldbrk == newbrk) |
| 291 | goto set_brk; |
| 292 | |
| 293 | /* Always allow shrinking brk. */ |
| 294 | if (brk <= mm->brk) { |
| 295 | if (!do_munmap(mm, newbrk, oldbrk-newbrk)) |
| 296 | goto set_brk; |
| 297 | goto out; |
| 298 | } |
| 299 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 300 | /* Check against existing mmap mappings. */ |
| 301 | if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE)) |
| 302 | goto out; |
| 303 | |
| 304 | /* Ok, looks good - let it rip. */ |
| 305 | if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk) |
| 306 | goto out; |
| 307 | set_brk: |
| 308 | mm->brk = brk; |
| 309 | out: |
| 310 | retval = mm->brk; |
| 311 | up_write(&mm->mmap_sem); |
| 312 | return retval; |
| 313 | } |
| 314 | |
Michel Lespinasse | d373718 | 2012-12-11 16:01:38 -0800 | [diff] [blame] | 315 | static long vma_compute_subtree_gap(struct vm_area_struct *vma) |
| 316 | { |
| 317 | unsigned long max, subtree_gap; |
| 318 | max = vma->vm_start; |
| 319 | if (vma->vm_prev) |
| 320 | max -= vma->vm_prev->vm_end; |
| 321 | if (vma->vm_rb.rb_left) { |
| 322 | subtree_gap = rb_entry(vma->vm_rb.rb_left, |
| 323 | struct vm_area_struct, vm_rb)->rb_subtree_gap; |
| 324 | if (subtree_gap > max) |
| 325 | max = subtree_gap; |
| 326 | } |
| 327 | if (vma->vm_rb.rb_right) { |
| 328 | subtree_gap = rb_entry(vma->vm_rb.rb_right, |
| 329 | struct vm_area_struct, vm_rb)->rb_subtree_gap; |
| 330 | if (subtree_gap > max) |
| 331 | max = subtree_gap; |
| 332 | } |
| 333 | return max; |
| 334 | } |
| 335 | |
Michel Lespinasse | ed8ea81 | 2012-10-08 16:31:45 -0700 | [diff] [blame] | 336 | #ifdef CONFIG_DEBUG_VM_RB |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 337 | static int browse_rb(struct rb_root *root) |
| 338 | { |
Michel Lespinasse | 5a0768f | 2012-12-11 16:01:42 -0800 | [diff] [blame] | 339 | int i = 0, j, bug = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 340 | struct rb_node *nd, *pn = NULL; |
| 341 | unsigned long prev = 0, pend = 0; |
| 342 | |
| 343 | for (nd = rb_first(root); nd; nd = rb_next(nd)) { |
| 344 | struct vm_area_struct *vma; |
| 345 | vma = rb_entry(nd, struct vm_area_struct, vm_rb); |
Michel Lespinasse | 5a0768f | 2012-12-11 16:01:42 -0800 | [diff] [blame] | 346 | if (vma->vm_start < prev) { |
| 347 | printk("vm_start %lx prev %lx\n", vma->vm_start, prev); |
| 348 | bug = 1; |
| 349 | } |
| 350 | if (vma->vm_start < pend) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 351 | printk("vm_start %lx pend %lx\n", vma->vm_start, pend); |
Michel Lespinasse | 5a0768f | 2012-12-11 16:01:42 -0800 | [diff] [blame] | 352 | bug = 1; |
| 353 | } |
| 354 | if (vma->vm_start > vma->vm_end) { |
| 355 | printk("vm_end %lx < vm_start %lx\n", |
| 356 | vma->vm_end, vma->vm_start); |
| 357 | bug = 1; |
| 358 | } |
| 359 | if (vma->rb_subtree_gap != vma_compute_subtree_gap(vma)) { |
| 360 | printk("free gap %lx, correct %lx\n", |
| 361 | vma->rb_subtree_gap, |
| 362 | vma_compute_subtree_gap(vma)); |
| 363 | bug = 1; |
| 364 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 365 | i++; |
| 366 | pn = nd; |
David Miller | d1af65d | 2007-02-28 20:13:13 -0800 | [diff] [blame] | 367 | prev = vma->vm_start; |
| 368 | pend = vma->vm_end; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 369 | } |
| 370 | j = 0; |
Michel Lespinasse | 5a0768f | 2012-12-11 16:01:42 -0800 | [diff] [blame] | 371 | for (nd = pn; nd; nd = rb_prev(nd)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 372 | j++; |
Michel Lespinasse | 5a0768f | 2012-12-11 16:01:42 -0800 | [diff] [blame] | 373 | if (i != j) { |
| 374 | printk("backwards %d, forwards %d\n", j, i); |
| 375 | bug = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 376 | } |
Michel Lespinasse | 5a0768f | 2012-12-11 16:01:42 -0800 | [diff] [blame] | 377 | return bug ? -1 : i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 378 | } |
| 379 | |
Michel Lespinasse | d373718 | 2012-12-11 16:01:38 -0800 | [diff] [blame] | 380 | static void validate_mm_rb(struct rb_root *root, struct vm_area_struct *ignore) |
| 381 | { |
| 382 | struct rb_node *nd; |
| 383 | |
| 384 | for (nd = rb_first(root); nd; nd = rb_next(nd)) { |
| 385 | struct vm_area_struct *vma; |
| 386 | vma = rb_entry(nd, struct vm_area_struct, vm_rb); |
| 387 | BUG_ON(vma != ignore && |
| 388 | vma->rb_subtree_gap != vma_compute_subtree_gap(vma)); |
| 389 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 390 | } |
| 391 | |
| 392 | void validate_mm(struct mm_struct *mm) |
| 393 | { |
| 394 | int bug = 0; |
| 395 | int i = 0; |
Michel Lespinasse | 5a0768f | 2012-12-11 16:01:42 -0800 | [diff] [blame] | 396 | unsigned long highest_address = 0; |
Michel Lespinasse | ed8ea81 | 2012-10-08 16:31:45 -0700 | [diff] [blame] | 397 | struct vm_area_struct *vma = mm->mmap; |
| 398 | while (vma) { |
| 399 | struct anon_vma_chain *avc; |
Michel Lespinasse | 63c3b90 | 2012-11-16 14:14:47 -0800 | [diff] [blame] | 400 | vma_lock_anon_vma(vma); |
Michel Lespinasse | ed8ea81 | 2012-10-08 16:31:45 -0700 | [diff] [blame] | 401 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) |
| 402 | anon_vma_interval_tree_verify(avc); |
Michel Lespinasse | 63c3b90 | 2012-11-16 14:14:47 -0800 | [diff] [blame] | 403 | vma_unlock_anon_vma(vma); |
Michel Lespinasse | 5a0768f | 2012-12-11 16:01:42 -0800 | [diff] [blame] | 404 | highest_address = vma->vm_end; |
Michel Lespinasse | ed8ea81 | 2012-10-08 16:31:45 -0700 | [diff] [blame] | 405 | vma = vma->vm_next; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 406 | i++; |
| 407 | } |
Michel Lespinasse | 5a0768f | 2012-12-11 16:01:42 -0800 | [diff] [blame] | 408 | if (i != mm->map_count) { |
| 409 | printk("map_count %d vm_next %d\n", mm->map_count, i); |
| 410 | bug = 1; |
| 411 | } |
| 412 | if (highest_address != mm->highest_vm_end) { |
| 413 | printk("mm->highest_vm_end %lx, found %lx\n", |
| 414 | mm->highest_vm_end, highest_address); |
| 415 | bug = 1; |
| 416 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 417 | i = browse_rb(&mm->mm_rb); |
Michel Lespinasse | 5a0768f | 2012-12-11 16:01:42 -0800 | [diff] [blame] | 418 | if (i != mm->map_count) { |
| 419 | printk("map_count %d rb %d\n", mm->map_count, i); |
| 420 | bug = 1; |
| 421 | } |
Eric Sesterhenn | 46a350e | 2006-04-01 01:23:29 +0200 | [diff] [blame] | 422 | BUG_ON(bug); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 423 | } |
| 424 | #else |
Michel Lespinasse | d373718 | 2012-12-11 16:01:38 -0800 | [diff] [blame] | 425 | #define validate_mm_rb(root, ignore) do { } while (0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 426 | #define validate_mm(mm) do { } while (0) |
| 427 | #endif |
| 428 | |
Michel Lespinasse | d373718 | 2012-12-11 16:01:38 -0800 | [diff] [blame] | 429 | RB_DECLARE_CALLBACKS(static, vma_gap_callbacks, struct vm_area_struct, vm_rb, |
| 430 | unsigned long, rb_subtree_gap, vma_compute_subtree_gap) |
| 431 | |
| 432 | /* |
| 433 | * Update augmented rbtree rb_subtree_gap values after vma->vm_start or |
| 434 | * vma->vm_prev->vm_end values changed, without modifying the vma's position |
| 435 | * in the rbtree. |
| 436 | */ |
| 437 | static void vma_gap_update(struct vm_area_struct *vma) |
| 438 | { |
| 439 | /* |
| 440 | * As it turns out, RB_DECLARE_CALLBACKS() already created a callback |
| 441 | * function that does exacltly what we want. |
| 442 | */ |
| 443 | vma_gap_callbacks_propagate(&vma->vm_rb, NULL); |
| 444 | } |
| 445 | |
| 446 | static inline void vma_rb_insert(struct vm_area_struct *vma, |
| 447 | struct rb_root *root) |
| 448 | { |
| 449 | /* All rb_subtree_gap values must be consistent prior to insertion */ |
| 450 | validate_mm_rb(root, NULL); |
| 451 | |
| 452 | rb_insert_augmented(&vma->vm_rb, root, &vma_gap_callbacks); |
| 453 | } |
| 454 | |
| 455 | static void vma_rb_erase(struct vm_area_struct *vma, struct rb_root *root) |
| 456 | { |
| 457 | /* |
| 458 | * All rb_subtree_gap values must be consistent prior to erase, |
| 459 | * with the possible exception of the vma being erased. |
| 460 | */ |
| 461 | validate_mm_rb(root, vma); |
| 462 | |
| 463 | /* |
| 464 | * Note rb_erase_augmented is a fairly large inline function, |
| 465 | * so make sure we instantiate it only once with our desired |
| 466 | * augmented rbtree callbacks. |
| 467 | */ |
| 468 | rb_erase_augmented(&vma->vm_rb, root, &vma_gap_callbacks); |
| 469 | } |
| 470 | |
Michel Lespinasse | bf181b9 | 2012-10-08 16:31:39 -0700 | [diff] [blame] | 471 | /* |
| 472 | * vma has some anon_vma assigned, and is already inserted on that |
| 473 | * anon_vma's interval trees. |
| 474 | * |
| 475 | * Before updating the vma's vm_start / vm_end / vm_pgoff fields, the |
| 476 | * vma must be removed from the anon_vma's interval trees using |
| 477 | * anon_vma_interval_tree_pre_update_vma(). |
| 478 | * |
| 479 | * After the update, the vma will be reinserted using |
| 480 | * anon_vma_interval_tree_post_update_vma(). |
| 481 | * |
| 482 | * The entire update must be protected by exclusive mmap_sem and by |
| 483 | * the root anon_vma's mutex. |
| 484 | */ |
| 485 | static inline void |
| 486 | anon_vma_interval_tree_pre_update_vma(struct vm_area_struct *vma) |
| 487 | { |
| 488 | struct anon_vma_chain *avc; |
| 489 | |
| 490 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) |
| 491 | anon_vma_interval_tree_remove(avc, &avc->anon_vma->rb_root); |
| 492 | } |
| 493 | |
| 494 | static inline void |
| 495 | anon_vma_interval_tree_post_update_vma(struct vm_area_struct *vma) |
| 496 | { |
| 497 | struct anon_vma_chain *avc; |
| 498 | |
| 499 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) |
| 500 | anon_vma_interval_tree_insert(avc, &avc->anon_vma->rb_root); |
| 501 | } |
| 502 | |
Hugh Dickins | 6597d78 | 2012-10-08 16:29:07 -0700 | [diff] [blame] | 503 | static int find_vma_links(struct mm_struct *mm, unsigned long addr, |
| 504 | unsigned long end, struct vm_area_struct **pprev, |
| 505 | struct rb_node ***rb_link, struct rb_node **rb_parent) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 506 | { |
Hugh Dickins | 6597d78 | 2012-10-08 16:29:07 -0700 | [diff] [blame] | 507 | struct rb_node **__rb_link, *__rb_parent, *rb_prev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 508 | |
| 509 | __rb_link = &mm->mm_rb.rb_node; |
| 510 | rb_prev = __rb_parent = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 511 | |
| 512 | while (*__rb_link) { |
| 513 | struct vm_area_struct *vma_tmp; |
| 514 | |
| 515 | __rb_parent = *__rb_link; |
| 516 | vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb); |
| 517 | |
| 518 | if (vma_tmp->vm_end > addr) { |
Hugh Dickins | 6597d78 | 2012-10-08 16:29:07 -0700 | [diff] [blame] | 519 | /* Fail if an existing vma overlaps the area */ |
| 520 | if (vma_tmp->vm_start < end) |
| 521 | return -ENOMEM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 522 | __rb_link = &__rb_parent->rb_left; |
| 523 | } else { |
| 524 | rb_prev = __rb_parent; |
| 525 | __rb_link = &__rb_parent->rb_right; |
| 526 | } |
| 527 | } |
| 528 | |
| 529 | *pprev = NULL; |
| 530 | if (rb_prev) |
| 531 | *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb); |
| 532 | *rb_link = __rb_link; |
| 533 | *rb_parent = __rb_parent; |
Hugh Dickins | 6597d78 | 2012-10-08 16:29:07 -0700 | [diff] [blame] | 534 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 535 | } |
| 536 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 537 | void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma, |
| 538 | struct rb_node **rb_link, struct rb_node *rb_parent) |
| 539 | { |
Michel Lespinasse | d373718 | 2012-12-11 16:01:38 -0800 | [diff] [blame] | 540 | /* Update tracking information for the gap following the new vma. */ |
| 541 | if (vma->vm_next) |
| 542 | vma_gap_update(vma->vm_next); |
| 543 | else |
| 544 | mm->highest_vm_end = vma->vm_end; |
| 545 | |
| 546 | /* |
| 547 | * vma->vm_prev wasn't known when we followed the rbtree to find the |
| 548 | * correct insertion point for that vma. As a result, we could not |
| 549 | * update the vma vm_rb parents rb_subtree_gap values on the way down. |
| 550 | * So, we first insert the vma with a zero rb_subtree_gap value |
| 551 | * (to be consistent with what we did on the way down), and then |
| 552 | * immediately update the gap to the correct value. Finally we |
| 553 | * rebalance the rbtree after all augmented values have been set. |
| 554 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 555 | rb_link_node(&vma->vm_rb, rb_parent, rb_link); |
Michel Lespinasse | d373718 | 2012-12-11 16:01:38 -0800 | [diff] [blame] | 556 | vma->rb_subtree_gap = 0; |
| 557 | vma_gap_update(vma); |
| 558 | vma_rb_insert(vma, &mm->mm_rb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 559 | } |
| 560 | |
Denys Vlasenko | cb8f488 | 2008-10-18 20:27:01 -0700 | [diff] [blame] | 561 | static void __vma_link_file(struct vm_area_struct *vma) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 562 | { |
ZhenwenXu | 48aae42 | 2009-01-06 14:40:21 -0800 | [diff] [blame] | 563 | struct file *file; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 564 | |
| 565 | file = vma->vm_file; |
| 566 | if (file) { |
| 567 | struct address_space *mapping = file->f_mapping; |
| 568 | |
| 569 | if (vma->vm_flags & VM_DENYWRITE) |
Josef "Jeff" Sipek | d3ac7f8 | 2006-12-08 02:36:44 -0800 | [diff] [blame] | 570 | atomic_dec(&file->f_path.dentry->d_inode->i_writecount); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 571 | if (vma->vm_flags & VM_SHARED) |
| 572 | mapping->i_mmap_writable++; |
| 573 | |
| 574 | flush_dcache_mmap_lock(mapping); |
| 575 | if (unlikely(vma->vm_flags & VM_NONLINEAR)) |
| 576 | vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear); |
| 577 | else |
Michel Lespinasse | 6b2dbba | 2012-10-08 16:31:25 -0700 | [diff] [blame] | 578 | vma_interval_tree_insert(vma, &mapping->i_mmap); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 579 | flush_dcache_mmap_unlock(mapping); |
| 580 | } |
| 581 | } |
| 582 | |
| 583 | static void |
| 584 | __vma_link(struct mm_struct *mm, struct vm_area_struct *vma, |
| 585 | struct vm_area_struct *prev, struct rb_node **rb_link, |
| 586 | struct rb_node *rb_parent) |
| 587 | { |
| 588 | __vma_link_list(mm, vma, prev, rb_parent); |
| 589 | __vma_link_rb(mm, vma, rb_link, rb_parent); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 590 | } |
| 591 | |
| 592 | static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma, |
| 593 | struct vm_area_struct *prev, struct rb_node **rb_link, |
| 594 | struct rb_node *rb_parent) |
| 595 | { |
| 596 | struct address_space *mapping = NULL; |
| 597 | |
| 598 | if (vma->vm_file) |
| 599 | mapping = vma->vm_file->f_mapping; |
| 600 | |
Peter Zijlstra | 97a8941 | 2011-05-24 17:12:04 -0700 | [diff] [blame] | 601 | if (mapping) |
Peter Zijlstra | 3d48ae4 | 2011-05-24 17:12:06 -0700 | [diff] [blame] | 602 | mutex_lock(&mapping->i_mmap_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 603 | |
| 604 | __vma_link(mm, vma, prev, rb_link, rb_parent); |
| 605 | __vma_link_file(vma); |
| 606 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 607 | if (mapping) |
Peter Zijlstra | 3d48ae4 | 2011-05-24 17:12:06 -0700 | [diff] [blame] | 608 | mutex_unlock(&mapping->i_mmap_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 609 | |
| 610 | mm->map_count++; |
| 611 | validate_mm(mm); |
| 612 | } |
| 613 | |
| 614 | /* |
Kautuk Consul | 88f6b4c | 2012-03-21 16:34:16 -0700 | [diff] [blame] | 615 | * Helper for vma_adjust() in the split_vma insert case: insert a vma into the |
Michel Lespinasse | 6b2dbba | 2012-10-08 16:31:25 -0700 | [diff] [blame] | 616 | * mm's list and rbtree. It has already been inserted into the interval tree. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 617 | */ |
ZhenwenXu | 48aae42 | 2009-01-06 14:40:21 -0800 | [diff] [blame] | 618 | static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 619 | { |
Hugh Dickins | 6597d78 | 2012-10-08 16:29:07 -0700 | [diff] [blame] | 620 | struct vm_area_struct *prev; |
ZhenwenXu | 48aae42 | 2009-01-06 14:40:21 -0800 | [diff] [blame] | 621 | struct rb_node **rb_link, *rb_parent; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 622 | |
Hugh Dickins | 6597d78 | 2012-10-08 16:29:07 -0700 | [diff] [blame] | 623 | if (find_vma_links(mm, vma->vm_start, vma->vm_end, |
| 624 | &prev, &rb_link, &rb_parent)) |
| 625 | BUG(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 626 | __vma_link(mm, vma, prev, rb_link, rb_parent); |
| 627 | mm->map_count++; |
| 628 | } |
| 629 | |
| 630 | static inline void |
| 631 | __vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma, |
| 632 | struct vm_area_struct *prev) |
| 633 | { |
Michel Lespinasse | d373718 | 2012-12-11 16:01:38 -0800 | [diff] [blame] | 634 | struct vm_area_struct *next; |
Linus Torvalds | 297c5ee | 2010-08-20 16:24:55 -0700 | [diff] [blame] | 635 | |
Michel Lespinasse | d373718 | 2012-12-11 16:01:38 -0800 | [diff] [blame] | 636 | vma_rb_erase(vma, &mm->mm_rb); |
| 637 | prev->vm_next = next = vma->vm_next; |
Linus Torvalds | 297c5ee | 2010-08-20 16:24:55 -0700 | [diff] [blame] | 638 | if (next) |
| 639 | next->vm_prev = prev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 640 | if (mm->mmap_cache == vma) |
| 641 | mm->mmap_cache = prev; |
| 642 | } |
| 643 | |
| 644 | /* |
| 645 | * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that |
| 646 | * is already present in an i_mmap tree without adjusting the tree. |
| 647 | * The following helper function should be used when such adjustments |
| 648 | * are necessary. The "insert" vma (if any) is to be inserted |
| 649 | * before we drop the necessary locks. |
| 650 | */ |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 651 | int vma_adjust(struct vm_area_struct *vma, unsigned long start, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 652 | unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert) |
| 653 | { |
| 654 | struct mm_struct *mm = vma->vm_mm; |
| 655 | struct vm_area_struct *next = vma->vm_next; |
| 656 | struct vm_area_struct *importer = NULL; |
| 657 | struct address_space *mapping = NULL; |
Michel Lespinasse | 6b2dbba | 2012-10-08 16:31:25 -0700 | [diff] [blame] | 658 | struct rb_root *root = NULL; |
Rik van Riel | 012f1800 | 2010-08-09 17:18:40 -0700 | [diff] [blame] | 659 | struct anon_vma *anon_vma = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 660 | struct file *file = vma->vm_file; |
Michel Lespinasse | d373718 | 2012-12-11 16:01:38 -0800 | [diff] [blame] | 661 | bool start_changed = false, end_changed = false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 662 | long adjust_next = 0; |
| 663 | int remove_next = 0; |
| 664 | |
| 665 | if (next && !insert) { |
Linus Torvalds | 287d97a | 2010-04-10 15:22:30 -0700 | [diff] [blame] | 666 | struct vm_area_struct *exporter = NULL; |
| 667 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 668 | if (end >= next->vm_end) { |
| 669 | /* |
| 670 | * vma expands, overlapping all the next, and |
| 671 | * perhaps the one after too (mprotect case 6). |
| 672 | */ |
| 673 | again: remove_next = 1 + (end > next->vm_end); |
| 674 | end = next->vm_end; |
Linus Torvalds | 287d97a | 2010-04-10 15:22:30 -0700 | [diff] [blame] | 675 | exporter = next; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 676 | importer = vma; |
| 677 | } else if (end > next->vm_start) { |
| 678 | /* |
| 679 | * vma expands, overlapping part of the next: |
| 680 | * mprotect case 5 shifting the boundary up. |
| 681 | */ |
| 682 | adjust_next = (end - next->vm_start) >> PAGE_SHIFT; |
Linus Torvalds | 287d97a | 2010-04-10 15:22:30 -0700 | [diff] [blame] | 683 | exporter = next; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 684 | importer = vma; |
| 685 | } else if (end < vma->vm_end) { |
| 686 | /* |
| 687 | * vma shrinks, and !insert tells it's not |
| 688 | * split_vma inserting another: so it must be |
| 689 | * mprotect case 4 shifting the boundary down. |
| 690 | */ |
| 691 | adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT); |
Linus Torvalds | 287d97a | 2010-04-10 15:22:30 -0700 | [diff] [blame] | 692 | exporter = vma; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 693 | importer = next; |
| 694 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 695 | |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 696 | /* |
| 697 | * Easily overlooked: when mprotect shifts the boundary, |
| 698 | * make sure the expanding vma has anon_vma set if the |
| 699 | * shrinking vma had, to cover any anon pages imported. |
| 700 | */ |
Linus Torvalds | 287d97a | 2010-04-10 15:22:30 -0700 | [diff] [blame] | 701 | if (exporter && exporter->anon_vma && !importer->anon_vma) { |
| 702 | if (anon_vma_clone(importer, exporter)) |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 703 | return -ENOMEM; |
Linus Torvalds | 287d97a | 2010-04-10 15:22:30 -0700 | [diff] [blame] | 704 | importer->anon_vma = exporter->anon_vma; |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 705 | } |
| 706 | } |
| 707 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 708 | if (file) { |
| 709 | mapping = file->f_mapping; |
Srikar Dronamraju | 682968e | 2012-03-30 23:56:46 +0530 | [diff] [blame] | 710 | if (!(vma->vm_flags & VM_NONLINEAR)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 711 | root = &mapping->i_mmap; |
Srikar Dronamraju | cbc91f7 | 2012-04-11 16:05:27 +0530 | [diff] [blame] | 712 | uprobe_munmap(vma, vma->vm_start, vma->vm_end); |
Srikar Dronamraju | 682968e | 2012-03-30 23:56:46 +0530 | [diff] [blame] | 713 | |
| 714 | if (adjust_next) |
Srikar Dronamraju | cbc91f7 | 2012-04-11 16:05:27 +0530 | [diff] [blame] | 715 | uprobe_munmap(next, next->vm_start, |
| 716 | next->vm_end); |
Srikar Dronamraju | 682968e | 2012-03-30 23:56:46 +0530 | [diff] [blame] | 717 | } |
| 718 | |
Peter Zijlstra | 3d48ae4 | 2011-05-24 17:12:06 -0700 | [diff] [blame] | 719 | mutex_lock(&mapping->i_mmap_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 720 | if (insert) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 721 | /* |
Michel Lespinasse | 6b2dbba | 2012-10-08 16:31:25 -0700 | [diff] [blame] | 722 | * Put into interval tree now, so instantiated pages |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 723 | * are visible to arm/parisc __flush_dcache_page |
| 724 | * throughout; but we cannot insert into address |
| 725 | * space until vma start or end is updated. |
| 726 | */ |
| 727 | __vma_link_file(insert); |
| 728 | } |
| 729 | } |
| 730 | |
Andrea Arcangeli | 94fcc58 | 2011-01-13 15:47:08 -0800 | [diff] [blame] | 731 | vma_adjust_trans_huge(vma, start, end, adjust_next); |
| 732 | |
Michel Lespinasse | bf181b9 | 2012-10-08 16:31:39 -0700 | [diff] [blame] | 733 | anon_vma = vma->anon_vma; |
| 734 | if (!anon_vma && adjust_next) |
| 735 | anon_vma = next->anon_vma; |
| 736 | if (anon_vma) { |
Michel Lespinasse | ca42b26 | 2012-10-08 16:30:01 -0700 | [diff] [blame] | 737 | VM_BUG_ON(adjust_next && next->anon_vma && |
| 738 | anon_vma != next->anon_vma); |
Ingo Molnar | 4fc3f1d | 2012-12-02 19:56:50 +0000 | [diff] [blame] | 739 | anon_vma_lock_write(anon_vma); |
Michel Lespinasse | bf181b9 | 2012-10-08 16:31:39 -0700 | [diff] [blame] | 740 | anon_vma_interval_tree_pre_update_vma(vma); |
| 741 | if (adjust_next) |
| 742 | anon_vma_interval_tree_pre_update_vma(next); |
| 743 | } |
Rik van Riel | 012f1800 | 2010-08-09 17:18:40 -0700 | [diff] [blame] | 744 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 745 | if (root) { |
| 746 | flush_dcache_mmap_lock(mapping); |
Michel Lespinasse | 6b2dbba | 2012-10-08 16:31:25 -0700 | [diff] [blame] | 747 | vma_interval_tree_remove(vma, root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 748 | if (adjust_next) |
Michel Lespinasse | 6b2dbba | 2012-10-08 16:31:25 -0700 | [diff] [blame] | 749 | vma_interval_tree_remove(next, root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 750 | } |
| 751 | |
Michel Lespinasse | d373718 | 2012-12-11 16:01:38 -0800 | [diff] [blame] | 752 | if (start != vma->vm_start) { |
| 753 | vma->vm_start = start; |
| 754 | start_changed = true; |
| 755 | } |
| 756 | if (end != vma->vm_end) { |
| 757 | vma->vm_end = end; |
| 758 | end_changed = true; |
| 759 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 760 | vma->vm_pgoff = pgoff; |
| 761 | if (adjust_next) { |
| 762 | next->vm_start += adjust_next << PAGE_SHIFT; |
| 763 | next->vm_pgoff += adjust_next; |
| 764 | } |
| 765 | |
| 766 | if (root) { |
| 767 | if (adjust_next) |
Michel Lespinasse | 6b2dbba | 2012-10-08 16:31:25 -0700 | [diff] [blame] | 768 | vma_interval_tree_insert(next, root); |
| 769 | vma_interval_tree_insert(vma, root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 770 | flush_dcache_mmap_unlock(mapping); |
| 771 | } |
| 772 | |
| 773 | if (remove_next) { |
| 774 | /* |
| 775 | * vma_merge has merged next into vma, and needs |
| 776 | * us to remove next before dropping the locks. |
| 777 | */ |
| 778 | __vma_unlink(mm, next, vma); |
| 779 | if (file) |
| 780 | __remove_shared_vm_struct(next, file, mapping); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 781 | } else if (insert) { |
| 782 | /* |
| 783 | * split_vma has split insert from vma, and needs |
| 784 | * us to insert it before dropping the locks |
| 785 | * (it may either follow vma or precede it). |
| 786 | */ |
| 787 | __insert_vm_struct(mm, insert); |
Michel Lespinasse | d373718 | 2012-12-11 16:01:38 -0800 | [diff] [blame] | 788 | } else { |
| 789 | if (start_changed) |
| 790 | vma_gap_update(vma); |
| 791 | if (end_changed) { |
| 792 | if (!next) |
| 793 | mm->highest_vm_end = end; |
| 794 | else if (!adjust_next) |
| 795 | vma_gap_update(next); |
| 796 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 797 | } |
| 798 | |
Michel Lespinasse | bf181b9 | 2012-10-08 16:31:39 -0700 | [diff] [blame] | 799 | if (anon_vma) { |
| 800 | anon_vma_interval_tree_post_update_vma(vma); |
| 801 | if (adjust_next) |
| 802 | anon_vma_interval_tree_post_update_vma(next); |
Rik van Riel | 012f1800 | 2010-08-09 17:18:40 -0700 | [diff] [blame] | 803 | anon_vma_unlock(anon_vma); |
Michel Lespinasse | bf181b9 | 2012-10-08 16:31:39 -0700 | [diff] [blame] | 804 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 805 | if (mapping) |
Peter Zijlstra | 3d48ae4 | 2011-05-24 17:12:06 -0700 | [diff] [blame] | 806 | mutex_unlock(&mapping->i_mmap_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 807 | |
Srikar Dronamraju | 2b14449 | 2012-02-09 14:56:42 +0530 | [diff] [blame] | 808 | if (root) { |
Ingo Molnar | 7b2d81d | 2012-02-17 09:27:41 +0100 | [diff] [blame] | 809 | uprobe_mmap(vma); |
Srikar Dronamraju | 2b14449 | 2012-02-09 14:56:42 +0530 | [diff] [blame] | 810 | |
| 811 | if (adjust_next) |
Ingo Molnar | 7b2d81d | 2012-02-17 09:27:41 +0100 | [diff] [blame] | 812 | uprobe_mmap(next); |
Srikar Dronamraju | 2b14449 | 2012-02-09 14:56:42 +0530 | [diff] [blame] | 813 | } |
| 814 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 815 | if (remove_next) { |
Matt Helsley | 925d1c4 | 2008-04-29 01:01:36 -0700 | [diff] [blame] | 816 | if (file) { |
Srikar Dronamraju | cbc91f7 | 2012-04-11 16:05:27 +0530 | [diff] [blame] | 817 | uprobe_munmap(next, next->vm_start, next->vm_end); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 818 | fput(file); |
Matt Helsley | 925d1c4 | 2008-04-29 01:01:36 -0700 | [diff] [blame] | 819 | } |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 820 | if (next->anon_vma) |
| 821 | anon_vma_merge(vma, next); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 822 | mm->map_count--; |
Lee Schermerhorn | f0be3d3 | 2008-04-28 02:13:08 -0700 | [diff] [blame] | 823 | mpol_put(vma_policy(next)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 824 | kmem_cache_free(vm_area_cachep, next); |
| 825 | /* |
| 826 | * In mprotect's case 6 (see comments on vma_merge), |
| 827 | * we must remove another next too. It would clutter |
| 828 | * up the code too much to do both in one go. |
| 829 | */ |
Michel Lespinasse | d373718 | 2012-12-11 16:01:38 -0800 | [diff] [blame] | 830 | next = vma->vm_next; |
| 831 | if (remove_next == 2) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 832 | goto again; |
Michel Lespinasse | d373718 | 2012-12-11 16:01:38 -0800 | [diff] [blame] | 833 | else if (next) |
| 834 | vma_gap_update(next); |
| 835 | else |
| 836 | mm->highest_vm_end = end; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 837 | } |
Srikar Dronamraju | 2b14449 | 2012-02-09 14:56:42 +0530 | [diff] [blame] | 838 | if (insert && file) |
Ingo Molnar | 7b2d81d | 2012-02-17 09:27:41 +0100 | [diff] [blame] | 839 | uprobe_mmap(insert); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 840 | |
| 841 | validate_mm(mm); |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 842 | |
| 843 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 844 | } |
| 845 | |
| 846 | /* |
| 847 | * If the vma has a ->close operation then the driver probably needs to release |
| 848 | * per-vma resources, so we don't attempt to merge those. |
| 849 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 850 | static inline int is_mergeable_vma(struct vm_area_struct *vma, |
| 851 | struct file *file, unsigned long vm_flags) |
| 852 | { |
Konstantin Khlebnikov | 0b173bc | 2012-10-08 16:28:46 -0700 | [diff] [blame] | 853 | if (vma->vm_flags ^ vm_flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 854 | return 0; |
| 855 | if (vma->vm_file != file) |
| 856 | return 0; |
| 857 | if (vma->vm_ops && vma->vm_ops->close) |
| 858 | return 0; |
| 859 | return 1; |
| 860 | } |
| 861 | |
| 862 | static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1, |
Shaohua Li | 965f55d | 2011-05-24 17:11:20 -0700 | [diff] [blame] | 863 | struct anon_vma *anon_vma2, |
| 864 | struct vm_area_struct *vma) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 865 | { |
Shaohua Li | 965f55d | 2011-05-24 17:11:20 -0700 | [diff] [blame] | 866 | /* |
| 867 | * The list_is_singular() test is to avoid merging VMA cloned from |
| 868 | * parents. This can improve scalability caused by anon_vma lock. |
| 869 | */ |
| 870 | if ((!anon_vma1 || !anon_vma2) && (!vma || |
| 871 | list_is_singular(&vma->anon_vma_chain))) |
| 872 | return 1; |
| 873 | return anon_vma1 == anon_vma2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 874 | } |
| 875 | |
| 876 | /* |
| 877 | * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) |
| 878 | * in front of (at a lower virtual address and file offset than) the vma. |
| 879 | * |
| 880 | * We cannot merge two vmas if they have differently assigned (non-NULL) |
| 881 | * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. |
| 882 | * |
| 883 | * We don't check here for the merged mmap wrapping around the end of pagecache |
| 884 | * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which |
| 885 | * wrap, nor mmaps which cover the final page at index -1UL. |
| 886 | */ |
| 887 | static int |
| 888 | can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags, |
| 889 | struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) |
| 890 | { |
| 891 | if (is_mergeable_vma(vma, file, vm_flags) && |
Shaohua Li | 965f55d | 2011-05-24 17:11:20 -0700 | [diff] [blame] | 892 | is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 893 | if (vma->vm_pgoff == vm_pgoff) |
| 894 | return 1; |
| 895 | } |
| 896 | return 0; |
| 897 | } |
| 898 | |
| 899 | /* |
| 900 | * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) |
| 901 | * beyond (at a higher virtual address and file offset than) the vma. |
| 902 | * |
| 903 | * We cannot merge two vmas if they have differently assigned (non-NULL) |
| 904 | * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. |
| 905 | */ |
| 906 | static int |
| 907 | can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, |
| 908 | struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) |
| 909 | { |
| 910 | if (is_mergeable_vma(vma, file, vm_flags) && |
Shaohua Li | 965f55d | 2011-05-24 17:11:20 -0700 | [diff] [blame] | 911 | is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 912 | pgoff_t vm_pglen; |
| 913 | vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; |
| 914 | if (vma->vm_pgoff + vm_pglen == vm_pgoff) |
| 915 | return 1; |
| 916 | } |
| 917 | return 0; |
| 918 | } |
| 919 | |
| 920 | /* |
| 921 | * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out |
| 922 | * whether that can be merged with its predecessor or its successor. |
| 923 | * Or both (it neatly fills a hole). |
| 924 | * |
| 925 | * In most cases - when called for mmap, brk or mremap - [addr,end) is |
| 926 | * certain not to be mapped by the time vma_merge is called; but when |
| 927 | * called for mprotect, it is certain to be already mapped (either at |
| 928 | * an offset within prev, or at the start of next), and the flags of |
| 929 | * this area are about to be changed to vm_flags - and the no-change |
| 930 | * case has already been eliminated. |
| 931 | * |
| 932 | * The following mprotect cases have to be considered, where AAAA is |
| 933 | * the area passed down from mprotect_fixup, never extending beyond one |
| 934 | * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after: |
| 935 | * |
| 936 | * AAAA AAAA AAAA AAAA |
| 937 | * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX |
| 938 | * cannot merge might become might become might become |
| 939 | * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or |
| 940 | * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or |
| 941 | * mremap move: PPPPNNNNNNNN 8 |
| 942 | * AAAA |
| 943 | * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN |
| 944 | * might become case 1 below case 2 below case 3 below |
| 945 | * |
| 946 | * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX: |
| 947 | * mprotect_fixup updates vm_flags & vm_page_prot on successful return. |
| 948 | */ |
| 949 | struct vm_area_struct *vma_merge(struct mm_struct *mm, |
| 950 | struct vm_area_struct *prev, unsigned long addr, |
| 951 | unsigned long end, unsigned long vm_flags, |
| 952 | struct anon_vma *anon_vma, struct file *file, |
| 953 | pgoff_t pgoff, struct mempolicy *policy) |
| 954 | { |
| 955 | pgoff_t pglen = (end - addr) >> PAGE_SHIFT; |
| 956 | struct vm_area_struct *area, *next; |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 957 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 958 | |
| 959 | /* |
| 960 | * We later require that vma->vm_flags == vm_flags, |
| 961 | * so this tests vma->vm_flags & VM_SPECIAL, too. |
| 962 | */ |
| 963 | if (vm_flags & VM_SPECIAL) |
| 964 | return NULL; |
| 965 | |
| 966 | if (prev) |
| 967 | next = prev->vm_next; |
| 968 | else |
| 969 | next = mm->mmap; |
| 970 | area = next; |
| 971 | if (next && next->vm_end == end) /* cases 6, 7, 8 */ |
| 972 | next = next->vm_next; |
| 973 | |
| 974 | /* |
| 975 | * Can it merge with the predecessor? |
| 976 | */ |
| 977 | if (prev && prev->vm_end == addr && |
| 978 | mpol_equal(vma_policy(prev), policy) && |
| 979 | can_vma_merge_after(prev, vm_flags, |
| 980 | anon_vma, file, pgoff)) { |
| 981 | /* |
| 982 | * OK, it can. Can we now merge in the successor as well? |
| 983 | */ |
| 984 | if (next && end == next->vm_start && |
| 985 | mpol_equal(policy, vma_policy(next)) && |
| 986 | can_vma_merge_before(next, vm_flags, |
| 987 | anon_vma, file, pgoff+pglen) && |
| 988 | is_mergeable_anon_vma(prev->anon_vma, |
Shaohua Li | 965f55d | 2011-05-24 17:11:20 -0700 | [diff] [blame] | 989 | next->anon_vma, NULL)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 990 | /* cases 1, 6 */ |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 991 | err = vma_adjust(prev, prev->vm_start, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 992 | next->vm_end, prev->vm_pgoff, NULL); |
| 993 | } else /* cases 2, 5, 7 */ |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 994 | err = vma_adjust(prev, prev->vm_start, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 995 | end, prev->vm_pgoff, NULL); |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 996 | if (err) |
| 997 | return NULL; |
Andrea Arcangeli | b15d00b | 2011-01-13 15:46:59 -0800 | [diff] [blame] | 998 | khugepaged_enter_vma_merge(prev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 999 | return prev; |
| 1000 | } |
| 1001 | |
| 1002 | /* |
| 1003 | * Can this new request be merged in front of next? |
| 1004 | */ |
| 1005 | if (next && end == next->vm_start && |
| 1006 | mpol_equal(policy, vma_policy(next)) && |
| 1007 | can_vma_merge_before(next, vm_flags, |
| 1008 | anon_vma, file, pgoff+pglen)) { |
| 1009 | if (prev && addr < prev->vm_end) /* case 4 */ |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 1010 | err = vma_adjust(prev, prev->vm_start, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1011 | addr, prev->vm_pgoff, NULL); |
| 1012 | else /* cases 3, 8 */ |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 1013 | err = vma_adjust(area, addr, next->vm_end, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1014 | next->vm_pgoff - pglen, NULL); |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 1015 | if (err) |
| 1016 | return NULL; |
Andrea Arcangeli | b15d00b | 2011-01-13 15:46:59 -0800 | [diff] [blame] | 1017 | khugepaged_enter_vma_merge(area); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1018 | return area; |
| 1019 | } |
| 1020 | |
| 1021 | return NULL; |
| 1022 | } |
| 1023 | |
| 1024 | /* |
Linus Torvalds | d0e9fe1 | 2010-04-10 10:36:19 -0700 | [diff] [blame] | 1025 | * Rough compatbility check to quickly see if it's even worth looking |
| 1026 | * at sharing an anon_vma. |
| 1027 | * |
| 1028 | * They need to have the same vm_file, and the flags can only differ |
| 1029 | * in things that mprotect may change. |
| 1030 | * |
| 1031 | * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that |
| 1032 | * we can merge the two vma's. For example, we refuse to merge a vma if |
| 1033 | * there is a vm_ops->close() function, because that indicates that the |
| 1034 | * driver is doing some kind of reference counting. But that doesn't |
| 1035 | * really matter for the anon_vma sharing case. |
| 1036 | */ |
| 1037 | static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b) |
| 1038 | { |
| 1039 | return a->vm_end == b->vm_start && |
| 1040 | mpol_equal(vma_policy(a), vma_policy(b)) && |
| 1041 | a->vm_file == b->vm_file && |
| 1042 | !((a->vm_flags ^ b->vm_flags) & ~(VM_READ|VM_WRITE|VM_EXEC)) && |
| 1043 | b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT); |
| 1044 | } |
| 1045 | |
| 1046 | /* |
| 1047 | * Do some basic sanity checking to see if we can re-use the anon_vma |
| 1048 | * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be |
| 1049 | * the same as 'old', the other will be the new one that is trying |
| 1050 | * to share the anon_vma. |
| 1051 | * |
| 1052 | * NOTE! This runs with mm_sem held for reading, so it is possible that |
| 1053 | * the anon_vma of 'old' is concurrently in the process of being set up |
| 1054 | * by another page fault trying to merge _that_. But that's ok: if it |
| 1055 | * is being set up, that automatically means that it will be a singleton |
| 1056 | * acceptable for merging, so we can do all of this optimistically. But |
| 1057 | * we do that ACCESS_ONCE() to make sure that we never re-load the pointer. |
| 1058 | * |
| 1059 | * IOW: that the "list_is_singular()" test on the anon_vma_chain only |
| 1060 | * matters for the 'stable anon_vma' case (ie the thing we want to avoid |
| 1061 | * is to return an anon_vma that is "complex" due to having gone through |
| 1062 | * a fork). |
| 1063 | * |
| 1064 | * We also make sure that the two vma's are compatible (adjacent, |
| 1065 | * and with the same memory policies). That's all stable, even with just |
| 1066 | * a read lock on the mm_sem. |
| 1067 | */ |
| 1068 | static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_area_struct *a, struct vm_area_struct *b) |
| 1069 | { |
| 1070 | if (anon_vma_compatible(a, b)) { |
| 1071 | struct anon_vma *anon_vma = ACCESS_ONCE(old->anon_vma); |
| 1072 | |
| 1073 | if (anon_vma && list_is_singular(&old->anon_vma_chain)) |
| 1074 | return anon_vma; |
| 1075 | } |
| 1076 | return NULL; |
| 1077 | } |
| 1078 | |
| 1079 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1080 | * find_mergeable_anon_vma is used by anon_vma_prepare, to check |
| 1081 | * neighbouring vmas for a suitable anon_vma, before it goes off |
| 1082 | * to allocate a new anon_vma. It checks because a repetitive |
| 1083 | * sequence of mprotects and faults may otherwise lead to distinct |
| 1084 | * anon_vmas being allocated, preventing vma merge in subsequent |
| 1085 | * mprotect. |
| 1086 | */ |
| 1087 | struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma) |
| 1088 | { |
Linus Torvalds | d0e9fe1 | 2010-04-10 10:36:19 -0700 | [diff] [blame] | 1089 | struct anon_vma *anon_vma; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1090 | struct vm_area_struct *near; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1091 | |
| 1092 | near = vma->vm_next; |
| 1093 | if (!near) |
| 1094 | goto try_prev; |
| 1095 | |
Linus Torvalds | d0e9fe1 | 2010-04-10 10:36:19 -0700 | [diff] [blame] | 1096 | anon_vma = reusable_anon_vma(near, vma, near); |
| 1097 | if (anon_vma) |
| 1098 | return anon_vma; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1099 | try_prev: |
Linus Torvalds | 9be34c9 | 2011-06-16 00:35:09 -0700 | [diff] [blame] | 1100 | near = vma->vm_prev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1101 | if (!near) |
| 1102 | goto none; |
| 1103 | |
Linus Torvalds | d0e9fe1 | 2010-04-10 10:36:19 -0700 | [diff] [blame] | 1104 | anon_vma = reusable_anon_vma(near, near, vma); |
| 1105 | if (anon_vma) |
| 1106 | return anon_vma; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1107 | none: |
| 1108 | /* |
| 1109 | * There's no absolute need to look only at touching neighbours: |
| 1110 | * we could search further afield for "compatible" anon_vmas. |
| 1111 | * But it would probably just be a waste of time searching, |
| 1112 | * or lead to too many vmas hanging off the same anon_vma. |
| 1113 | * We're trying to allow mprotect remerging later on, |
| 1114 | * not trying to minimize memory used for anon_vmas. |
| 1115 | */ |
| 1116 | return NULL; |
| 1117 | } |
| 1118 | |
| 1119 | #ifdef CONFIG_PROC_FS |
Hugh Dickins | ab50b8e | 2005-10-29 18:15:56 -0700 | [diff] [blame] | 1120 | void vm_stat_account(struct mm_struct *mm, unsigned long flags, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1121 | struct file *file, long pages) |
| 1122 | { |
| 1123 | const unsigned long stack_flags |
| 1124 | = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN); |
| 1125 | |
Huang Shijie | 44de9d0 | 2012-07-31 16:41:49 -0700 | [diff] [blame] | 1126 | mm->total_vm += pages; |
| 1127 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1128 | if (file) { |
| 1129 | mm->shared_vm += pages; |
| 1130 | if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC) |
| 1131 | mm->exec_vm += pages; |
| 1132 | } else if (flags & stack_flags) |
| 1133 | mm->stack_vm += pages; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1134 | } |
| 1135 | #endif /* CONFIG_PROC_FS */ |
| 1136 | |
| 1137 | /* |
Al Viro | 4040153 | 2012-02-13 03:58:52 +0000 | [diff] [blame] | 1138 | * If a hint addr is less than mmap_min_addr change hint to be as |
| 1139 | * low as possible but still greater than mmap_min_addr |
| 1140 | */ |
| 1141 | static inline unsigned long round_hint_to_min(unsigned long hint) |
| 1142 | { |
| 1143 | hint &= PAGE_MASK; |
| 1144 | if (((void *)hint != NULL) && |
| 1145 | (hint < mmap_min_addr)) |
| 1146 | return PAGE_ALIGN(mmap_min_addr); |
| 1147 | return hint; |
| 1148 | } |
| 1149 | |
| 1150 | /* |
Jianjun Kong | 27f5de7 | 2009-09-17 19:26:26 -0700 | [diff] [blame] | 1151 | * The caller must hold down_write(¤t->mm->mmap_sem). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1152 | */ |
| 1153 | |
Al Viro | e3fc629 | 2012-05-30 20:08:42 -0400 | [diff] [blame] | 1154 | unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1155 | unsigned long len, unsigned long prot, |
| 1156 | unsigned long flags, unsigned long pgoff) |
| 1157 | { |
| 1158 | struct mm_struct * mm = current->mm; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1159 | struct inode *inode; |
KOSAKI Motohiro | ca16d14 | 2011-05-26 19:16:19 +0900 | [diff] [blame] | 1160 | vm_flags_t vm_flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1161 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1162 | /* |
| 1163 | * Does the application expect PROT_READ to imply PROT_EXEC? |
| 1164 | * |
| 1165 | * (the exception is when the underlying filesystem is noexec |
| 1166 | * mounted, in which case we dont add PROT_EXEC.) |
| 1167 | */ |
| 1168 | if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) |
Josef "Jeff" Sipek | d3ac7f8 | 2006-12-08 02:36:44 -0800 | [diff] [blame] | 1169 | if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1170 | prot |= PROT_EXEC; |
| 1171 | |
| 1172 | if (!len) |
| 1173 | return -EINVAL; |
| 1174 | |
Eric Paris | 7cd9414 | 2007-11-26 18:47:40 -0500 | [diff] [blame] | 1175 | if (!(flags & MAP_FIXED)) |
| 1176 | addr = round_hint_to_min(addr); |
| 1177 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1178 | /* Careful about overflows.. */ |
| 1179 | len = PAGE_ALIGN(len); |
Al Viro | 9206de9 | 2009-12-03 15:23:11 -0500 | [diff] [blame] | 1180 | if (!len) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1181 | return -ENOMEM; |
| 1182 | |
| 1183 | /* offset overflow? */ |
| 1184 | if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) |
| 1185 | return -EOVERFLOW; |
| 1186 | |
| 1187 | /* Too many mappings? */ |
| 1188 | if (mm->map_count > sysctl_max_map_count) |
| 1189 | return -ENOMEM; |
| 1190 | |
| 1191 | /* Obtain the address to map to. we verify (or select) it and ensure |
| 1192 | * that it represents a valid section of the address space. |
| 1193 | */ |
| 1194 | addr = get_unmapped_area(file, addr, len, pgoff, flags); |
| 1195 | if (addr & ~PAGE_MASK) |
| 1196 | return addr; |
| 1197 | |
| 1198 | /* Do simple checking here so the lower-level routines won't have |
| 1199 | * to. we assume access permissions have been handled by the open |
| 1200 | * of the memory object, so we don't do any here. |
| 1201 | */ |
| 1202 | vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) | |
| 1203 | mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; |
| 1204 | |
Huang Shijie | cdf7b34 | 2009-09-21 17:03:36 -0700 | [diff] [blame] | 1205 | if (flags & MAP_LOCKED) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1206 | if (!can_do_mlock()) |
| 1207 | return -EPERM; |
Rik van Riel | ba470de | 2008-10-18 20:26:50 -0700 | [diff] [blame] | 1208 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1209 | /* mlock MCL_FUTURE? */ |
| 1210 | if (vm_flags & VM_LOCKED) { |
| 1211 | unsigned long locked, lock_limit; |
Chris Wright | 93ea1d0 | 2005-05-01 08:58:38 -0700 | [diff] [blame] | 1212 | locked = len >> PAGE_SHIFT; |
| 1213 | locked += mm->locked_vm; |
Jiri Slaby | 59e99e5 | 2010-03-05 13:41:44 -0800 | [diff] [blame] | 1214 | lock_limit = rlimit(RLIMIT_MEMLOCK); |
Chris Wright | 93ea1d0 | 2005-05-01 08:58:38 -0700 | [diff] [blame] | 1215 | lock_limit >>= PAGE_SHIFT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1216 | if (locked > lock_limit && !capable(CAP_IPC_LOCK)) |
| 1217 | return -EAGAIN; |
| 1218 | } |
| 1219 | |
Josef "Jeff" Sipek | d3ac7f8 | 2006-12-08 02:36:44 -0800 | [diff] [blame] | 1220 | inode = file ? file->f_path.dentry->d_inode : NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1221 | |
| 1222 | if (file) { |
| 1223 | switch (flags & MAP_TYPE) { |
| 1224 | case MAP_SHARED: |
| 1225 | if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE)) |
| 1226 | return -EACCES; |
| 1227 | |
| 1228 | /* |
| 1229 | * Make sure we don't allow writing to an append-only |
| 1230 | * file.. |
| 1231 | */ |
| 1232 | if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE)) |
| 1233 | return -EACCES; |
| 1234 | |
| 1235 | /* |
| 1236 | * Make sure there are no mandatory locks on the file. |
| 1237 | */ |
| 1238 | if (locks_verify_locked(inode)) |
| 1239 | return -EAGAIN; |
| 1240 | |
| 1241 | vm_flags |= VM_SHARED | VM_MAYSHARE; |
| 1242 | if (!(file->f_mode & FMODE_WRITE)) |
| 1243 | vm_flags &= ~(VM_MAYWRITE | VM_SHARED); |
| 1244 | |
| 1245 | /* fall through */ |
| 1246 | case MAP_PRIVATE: |
| 1247 | if (!(file->f_mode & FMODE_READ)) |
| 1248 | return -EACCES; |
Josef "Jeff" Sipek | d3ac7f8 | 2006-12-08 02:36:44 -0800 | [diff] [blame] | 1249 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) { |
Linus Torvalds | 80c5606 | 2006-10-15 14:09:55 -0700 | [diff] [blame] | 1250 | if (vm_flags & VM_EXEC) |
| 1251 | return -EPERM; |
| 1252 | vm_flags &= ~VM_MAYEXEC; |
| 1253 | } |
Linus Torvalds | 80c5606 | 2006-10-15 14:09:55 -0700 | [diff] [blame] | 1254 | |
| 1255 | if (!file->f_op || !file->f_op->mmap) |
| 1256 | return -ENODEV; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1257 | break; |
| 1258 | |
| 1259 | default: |
| 1260 | return -EINVAL; |
| 1261 | } |
| 1262 | } else { |
| 1263 | switch (flags & MAP_TYPE) { |
| 1264 | case MAP_SHARED: |
Tejun Heo | ce36394 | 2008-09-03 16:09:47 +0200 | [diff] [blame] | 1265 | /* |
| 1266 | * Ignore pgoff. |
| 1267 | */ |
| 1268 | pgoff = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1269 | vm_flags |= VM_SHARED | VM_MAYSHARE; |
| 1270 | break; |
| 1271 | case MAP_PRIVATE: |
| 1272 | /* |
| 1273 | * Set pgoff according to addr for anon_vma. |
| 1274 | */ |
| 1275 | pgoff = addr >> PAGE_SHIFT; |
| 1276 | break; |
| 1277 | default: |
| 1278 | return -EINVAL; |
| 1279 | } |
| 1280 | } |
| 1281 | |
Mel Gorman | 5a6fe12 | 2009-02-10 14:02:27 +0000 | [diff] [blame] | 1282 | return mmap_region(file, addr, len, flags, vm_flags, pgoff); |
Miklos Szeredi | 0165ab4 | 2007-07-15 23:38:26 -0700 | [diff] [blame] | 1283 | } |
Linus Torvalds | 6be5ceb | 2012-04-20 17:13:58 -0700 | [diff] [blame] | 1284 | |
Hugh Dickins | 66f0dc4 | 2009-12-30 20:17:34 +0000 | [diff] [blame] | 1285 | SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, |
| 1286 | unsigned long, prot, unsigned long, flags, |
| 1287 | unsigned long, fd, unsigned long, pgoff) |
| 1288 | { |
| 1289 | struct file *file = NULL; |
| 1290 | unsigned long retval = -EBADF; |
| 1291 | |
| 1292 | if (!(flags & MAP_ANONYMOUS)) { |
Al Viro | 120a795 | 2010-10-30 02:54:44 -0400 | [diff] [blame] | 1293 | audit_mmap_fd(fd, flags); |
Hugh Dickins | 66f0dc4 | 2009-12-30 20:17:34 +0000 | [diff] [blame] | 1294 | if (unlikely(flags & MAP_HUGETLB)) |
| 1295 | return -EINVAL; |
| 1296 | file = fget(fd); |
| 1297 | if (!file) |
| 1298 | goto out; |
| 1299 | } else if (flags & MAP_HUGETLB) { |
| 1300 | struct user_struct *user = NULL; |
| 1301 | /* |
| 1302 | * VM_NORESERVE is used because the reservations will be |
| 1303 | * taken when vm_ops->mmap() is called |
| 1304 | * A dummy user value is used because we are not locking |
| 1305 | * memory so no accounting is necessary |
| 1306 | */ |
Steven Truelove | 40716e2 | 2012-03-21 16:34:14 -0700 | [diff] [blame] | 1307 | file = hugetlb_file_setup(HUGETLB_ANON_FILE, addr, len, |
Andi Kleen | 42d7395 | 2012-12-11 16:01:34 -0800 | [diff] [blame] | 1308 | VM_NORESERVE, |
| 1309 | &user, HUGETLB_ANONHUGE_INODE, |
| 1310 | (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); |
Hugh Dickins | 66f0dc4 | 2009-12-30 20:17:34 +0000 | [diff] [blame] | 1311 | if (IS_ERR(file)) |
| 1312 | return PTR_ERR(file); |
| 1313 | } |
| 1314 | |
| 1315 | flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE); |
| 1316 | |
Al Viro | eb36c58 | 2012-05-30 20:17:35 -0400 | [diff] [blame] | 1317 | retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff); |
Hugh Dickins | 66f0dc4 | 2009-12-30 20:17:34 +0000 | [diff] [blame] | 1318 | if (file) |
| 1319 | fput(file); |
| 1320 | out: |
| 1321 | return retval; |
| 1322 | } |
| 1323 | |
Christoph Hellwig | a467937 | 2010-03-10 15:21:15 -0800 | [diff] [blame] | 1324 | #ifdef __ARCH_WANT_SYS_OLD_MMAP |
| 1325 | struct mmap_arg_struct { |
| 1326 | unsigned long addr; |
| 1327 | unsigned long len; |
| 1328 | unsigned long prot; |
| 1329 | unsigned long flags; |
| 1330 | unsigned long fd; |
| 1331 | unsigned long offset; |
| 1332 | }; |
| 1333 | |
| 1334 | SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg) |
| 1335 | { |
| 1336 | struct mmap_arg_struct a; |
| 1337 | |
| 1338 | if (copy_from_user(&a, arg, sizeof(a))) |
| 1339 | return -EFAULT; |
| 1340 | if (a.offset & ~PAGE_MASK) |
| 1341 | return -EINVAL; |
| 1342 | |
| 1343 | return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, |
| 1344 | a.offset >> PAGE_SHIFT); |
| 1345 | } |
| 1346 | #endif /* __ARCH_WANT_SYS_OLD_MMAP */ |
| 1347 | |
Alexey Dobriyan | 4e950f6 | 2007-07-30 02:36:13 +0400 | [diff] [blame] | 1348 | /* |
| 1349 | * Some shared mappigns will want the pages marked read-only |
| 1350 | * to track write events. If so, we'll downgrade vm_page_prot |
| 1351 | * to the private version (using protection_map[] without the |
| 1352 | * VM_SHARED bit). |
| 1353 | */ |
| 1354 | int vma_wants_writenotify(struct vm_area_struct *vma) |
| 1355 | { |
KOSAKI Motohiro | ca16d14 | 2011-05-26 19:16:19 +0900 | [diff] [blame] | 1356 | vm_flags_t vm_flags = vma->vm_flags; |
Alexey Dobriyan | 4e950f6 | 2007-07-30 02:36:13 +0400 | [diff] [blame] | 1357 | |
| 1358 | /* If it was private or non-writable, the write bit is already clear */ |
| 1359 | if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED))) |
| 1360 | return 0; |
| 1361 | |
| 1362 | /* The backer wishes to know when pages are first written to? */ |
| 1363 | if (vma->vm_ops && vma->vm_ops->page_mkwrite) |
| 1364 | return 1; |
| 1365 | |
| 1366 | /* The open routine did something to the protections already? */ |
| 1367 | if (pgprot_val(vma->vm_page_prot) != |
Coly Li | 3ed75eb | 2007-10-18 23:39:15 -0700 | [diff] [blame] | 1368 | pgprot_val(vm_get_page_prot(vm_flags))) |
Alexey Dobriyan | 4e950f6 | 2007-07-30 02:36:13 +0400 | [diff] [blame] | 1369 | return 0; |
| 1370 | |
| 1371 | /* Specialty mapping? */ |
Konstantin Khlebnikov | 4b6e1e3 | 2012-10-08 16:28:40 -0700 | [diff] [blame] | 1372 | if (vm_flags & VM_PFNMAP) |
Alexey Dobriyan | 4e950f6 | 2007-07-30 02:36:13 +0400 | [diff] [blame] | 1373 | return 0; |
| 1374 | |
| 1375 | /* Can the mapping track the dirty pages? */ |
| 1376 | return vma->vm_file && vma->vm_file->f_mapping && |
| 1377 | mapping_cap_account_dirty(vma->vm_file->f_mapping); |
| 1378 | } |
| 1379 | |
Linus Torvalds | fc8744a | 2009-01-31 15:08:56 -0800 | [diff] [blame] | 1380 | /* |
| 1381 | * We account for memory if it's a private writeable mapping, |
Mel Gorman | 5a6fe12 | 2009-02-10 14:02:27 +0000 | [diff] [blame] | 1382 | * not hugepages and VM_NORESERVE wasn't set. |
Linus Torvalds | fc8744a | 2009-01-31 15:08:56 -0800 | [diff] [blame] | 1383 | */ |
KOSAKI Motohiro | ca16d14 | 2011-05-26 19:16:19 +0900 | [diff] [blame] | 1384 | static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags) |
Linus Torvalds | fc8744a | 2009-01-31 15:08:56 -0800 | [diff] [blame] | 1385 | { |
Mel Gorman | 5a6fe12 | 2009-02-10 14:02:27 +0000 | [diff] [blame] | 1386 | /* |
| 1387 | * hugetlb has its own accounting separate from the core VM |
| 1388 | * VM_HUGETLB may not be set yet so we cannot check for that flag. |
| 1389 | */ |
| 1390 | if (file && is_file_hugepages(file)) |
| 1391 | return 0; |
| 1392 | |
Linus Torvalds | fc8744a | 2009-01-31 15:08:56 -0800 | [diff] [blame] | 1393 | return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE; |
| 1394 | } |
| 1395 | |
Miklos Szeredi | 0165ab4 | 2007-07-15 23:38:26 -0700 | [diff] [blame] | 1396 | unsigned long mmap_region(struct file *file, unsigned long addr, |
| 1397 | unsigned long len, unsigned long flags, |
KOSAKI Motohiro | ca16d14 | 2011-05-26 19:16:19 +0900 | [diff] [blame] | 1398 | vm_flags_t vm_flags, unsigned long pgoff) |
Miklos Szeredi | 0165ab4 | 2007-07-15 23:38:26 -0700 | [diff] [blame] | 1399 | { |
| 1400 | struct mm_struct *mm = current->mm; |
| 1401 | struct vm_area_struct *vma, *prev; |
| 1402 | int correct_wcount = 0; |
| 1403 | int error; |
| 1404 | struct rb_node **rb_link, *rb_parent; |
| 1405 | unsigned long charged = 0; |
| 1406 | struct inode *inode = file ? file->f_path.dentry->d_inode : NULL; |
| 1407 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1408 | /* Clear old maps */ |
| 1409 | error = -ENOMEM; |
| 1410 | munmap_back: |
Hugh Dickins | 6597d78 | 2012-10-08 16:29:07 -0700 | [diff] [blame] | 1411 | if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1412 | if (do_munmap(mm, addr, len)) |
| 1413 | return -ENOMEM; |
| 1414 | goto munmap_back; |
| 1415 | } |
| 1416 | |
| 1417 | /* Check against address space limit. */ |
akpm@osdl.org | 119f657 | 2005-05-01 08:58:35 -0700 | [diff] [blame] | 1418 | if (!may_expand_vm(mm, len >> PAGE_SHIFT)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1419 | return -ENOMEM; |
| 1420 | |
Linus Torvalds | fc8744a | 2009-01-31 15:08:56 -0800 | [diff] [blame] | 1421 | /* |
| 1422 | * Set 'VM_NORESERVE' if we should not account for the |
Mel Gorman | 5a6fe12 | 2009-02-10 14:02:27 +0000 | [diff] [blame] | 1423 | * memory use of this mapping. |
Linus Torvalds | fc8744a | 2009-01-31 15:08:56 -0800 | [diff] [blame] | 1424 | */ |
Mel Gorman | 5a6fe12 | 2009-02-10 14:02:27 +0000 | [diff] [blame] | 1425 | if ((flags & MAP_NORESERVE)) { |
| 1426 | /* We honor MAP_NORESERVE if allowed to overcommit */ |
| 1427 | if (sysctl_overcommit_memory != OVERCOMMIT_NEVER) |
| 1428 | vm_flags |= VM_NORESERVE; |
| 1429 | |
| 1430 | /* hugetlb applies strict overcommit unless MAP_NORESERVE */ |
| 1431 | if (file && is_file_hugepages(file)) |
| 1432 | vm_flags |= VM_NORESERVE; |
| 1433 | } |
Andy Whitcroft | cdfd432 | 2008-07-23 21:27:28 -0700 | [diff] [blame] | 1434 | |
Linus Torvalds | fc8744a | 2009-01-31 15:08:56 -0800 | [diff] [blame] | 1435 | /* |
| 1436 | * Private writable mapping: check memory availability |
| 1437 | */ |
Mel Gorman | 5a6fe12 | 2009-02-10 14:02:27 +0000 | [diff] [blame] | 1438 | if (accountable_mapping(file, vm_flags)) { |
Linus Torvalds | fc8744a | 2009-01-31 15:08:56 -0800 | [diff] [blame] | 1439 | charged = len >> PAGE_SHIFT; |
Al Viro | 191c542 | 2012-02-13 03:58:52 +0000 | [diff] [blame] | 1440 | if (security_vm_enough_memory_mm(mm, charged)) |
Linus Torvalds | fc8744a | 2009-01-31 15:08:56 -0800 | [diff] [blame] | 1441 | return -ENOMEM; |
| 1442 | vm_flags |= VM_ACCOUNT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1443 | } |
| 1444 | |
| 1445 | /* |
Linus Torvalds | de33c8d | 2009-01-29 17:46:42 -0800 | [diff] [blame] | 1446 | * Can we just expand an old mapping? |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1447 | */ |
Linus Torvalds | de33c8d | 2009-01-29 17:46:42 -0800 | [diff] [blame] | 1448 | vma = vma_merge(mm, prev, addr, addr + len, vm_flags, NULL, file, pgoff, NULL); |
| 1449 | if (vma) |
| 1450 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1451 | |
| 1452 | /* |
| 1453 | * Determine the object being mapped and call the appropriate |
| 1454 | * specific mapper. the address has already been validated, but |
| 1455 | * not unmapped, but the maps are removed from the list. |
| 1456 | */ |
Pekka Enberg | c5e3b83 | 2006-03-25 03:06:43 -0800 | [diff] [blame] | 1457 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1458 | if (!vma) { |
| 1459 | error = -ENOMEM; |
| 1460 | goto unacct_error; |
| 1461 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1462 | |
| 1463 | vma->vm_mm = mm; |
| 1464 | vma->vm_start = addr; |
| 1465 | vma->vm_end = addr + len; |
| 1466 | vma->vm_flags = vm_flags; |
Coly Li | 3ed75eb | 2007-10-18 23:39:15 -0700 | [diff] [blame] | 1467 | vma->vm_page_prot = vm_get_page_prot(vm_flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1468 | vma->vm_pgoff = pgoff; |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 1469 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1470 | |
Hugh Dickins | ce8fea7a | 2012-03-06 12:28:52 -0800 | [diff] [blame] | 1471 | error = -EINVAL; /* when rejecting VM_GROWSDOWN|VM_GROWSUP */ |
| 1472 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1473 | if (file) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1474 | if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) |
| 1475 | goto free_vma; |
| 1476 | if (vm_flags & VM_DENYWRITE) { |
| 1477 | error = deny_write_access(file); |
| 1478 | if (error) |
| 1479 | goto free_vma; |
| 1480 | correct_wcount = 1; |
| 1481 | } |
Al Viro | cb0942b | 2012-08-27 14:48:26 -0400 | [diff] [blame] | 1482 | vma->vm_file = get_file(file); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1483 | error = file->f_op->mmap(file, vma); |
| 1484 | if (error) |
| 1485 | goto unmap_and_free_vma; |
Huang Shijie | f8dbf0a7 | 2009-09-21 17:03:41 -0700 | [diff] [blame] | 1486 | |
| 1487 | /* Can addr have changed?? |
| 1488 | * |
| 1489 | * Answer: Yes, several device drivers can do it in their |
| 1490 | * f_op->mmap method. -DaveM |
Joonsoo Kim | 2897b4d | 2012-12-12 13:51:53 -0800 | [diff] [blame] | 1491 | * Bug: If addr is changed, prev, rb_link, rb_parent should |
| 1492 | * be updated for vma_link() |
Huang Shijie | f8dbf0a7 | 2009-09-21 17:03:41 -0700 | [diff] [blame] | 1493 | */ |
Joonsoo Kim | 2897b4d | 2012-12-12 13:51:53 -0800 | [diff] [blame] | 1494 | WARN_ON_ONCE(addr != vma->vm_start); |
| 1495 | |
Huang Shijie | f8dbf0a7 | 2009-09-21 17:03:41 -0700 | [diff] [blame] | 1496 | addr = vma->vm_start; |
| 1497 | pgoff = vma->vm_pgoff; |
| 1498 | vm_flags = vma->vm_flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1499 | } else if (vm_flags & VM_SHARED) { |
Al Viro | 835ee79 | 2012-03-05 06:39:47 +0000 | [diff] [blame] | 1500 | if (unlikely(vm_flags & (VM_GROWSDOWN|VM_GROWSUP))) |
| 1501 | goto free_vma; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1502 | error = shmem_zero_setup(vma); |
| 1503 | if (error) |
| 1504 | goto free_vma; |
| 1505 | } |
| 1506 | |
Magnus Damm | c9d0bf2 | 2009-12-14 17:59:49 -0800 | [diff] [blame] | 1507 | if (vma_wants_writenotify(vma)) { |
| 1508 | pgprot_t pprot = vma->vm_page_prot; |
| 1509 | |
| 1510 | /* Can vma->vm_page_prot have changed?? |
| 1511 | * |
| 1512 | * Answer: Yes, drivers may have changed it in their |
| 1513 | * f_op->mmap method. |
| 1514 | * |
| 1515 | * Ensures that vmas marked as uncached stay that way. |
| 1516 | */ |
Hugh Dickins | 1ddd439 | 2007-10-22 20:45:12 -0700 | [diff] [blame] | 1517 | vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED); |
Magnus Damm | c9d0bf2 | 2009-12-14 17:59:49 -0800 | [diff] [blame] | 1518 | if (pgprot_val(pprot) == pgprot_val(pgprot_noncached(pprot))) |
| 1519 | vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); |
| 1520 | } |
Peter Zijlstra | d08b385 | 2006-09-25 23:30:57 -0700 | [diff] [blame] | 1521 | |
Linus Torvalds | de33c8d | 2009-01-29 17:46:42 -0800 | [diff] [blame] | 1522 | vma_link(mm, vma, prev, rb_link, rb_parent); |
| 1523 | file = vma->vm_file; |
Oleg Nesterov | 4d3d5b4 | 2008-04-28 02:12:10 -0700 | [diff] [blame] | 1524 | |
| 1525 | /* Once vma denies write, undo our temporary denial count */ |
| 1526 | if (correct_wcount) |
| 1527 | atomic_inc(&inode->i_writecount); |
| 1528 | out: |
Ingo Molnar | cdd6c48 | 2009-09-21 12:02:48 +0200 | [diff] [blame] | 1529 | perf_event_mmap(vma); |
Peter Zijlstra | 0a4a939 | 2009-03-30 19:07:05 +0200 | [diff] [blame] | 1530 | |
Hugh Dickins | ab50b8e | 2005-10-29 18:15:56 -0700 | [diff] [blame] | 1531 | vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1532 | if (vm_flags & VM_LOCKED) { |
KOSAKI Motohiro | 06f9d8c | 2010-03-05 13:41:43 -0800 | [diff] [blame] | 1533 | if (!mlock_vma_pages_range(vma, addr, addr + len)) |
| 1534 | mm->locked_vm += (len >> PAGE_SHIFT); |
Rik van Riel | ba470de | 2008-10-18 20:26:50 -0700 | [diff] [blame] | 1535 | } else if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK)) |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 1536 | make_pages_present(addr, addr + len); |
Srikar Dronamraju | 2b14449 | 2012-02-09 14:56:42 +0530 | [diff] [blame] | 1537 | |
Oleg Nesterov | c7a3a88 | 2012-08-19 19:10:42 +0200 | [diff] [blame] | 1538 | if (file) |
| 1539 | uprobe_mmap(vma); |
Srikar Dronamraju | 2b14449 | 2012-02-09 14:56:42 +0530 | [diff] [blame] | 1540 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1541 | return addr; |
| 1542 | |
| 1543 | unmap_and_free_vma: |
| 1544 | if (correct_wcount) |
| 1545 | atomic_inc(&inode->i_writecount); |
| 1546 | vma->vm_file = NULL; |
| 1547 | fput(file); |
| 1548 | |
| 1549 | /* Undo any partial mapping done by a device driver. */ |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 1550 | unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end); |
| 1551 | charged = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1552 | free_vma: |
| 1553 | kmem_cache_free(vm_area_cachep, vma); |
| 1554 | unacct_error: |
| 1555 | if (charged) |
| 1556 | vm_unacct_memory(charged); |
| 1557 | return error; |
| 1558 | } |
| 1559 | |
Michel Lespinasse | db4fbfb | 2012-12-11 16:01:49 -0800 | [diff] [blame] | 1560 | unsigned long unmapped_area(struct vm_unmapped_area_info *info) |
| 1561 | { |
| 1562 | /* |
| 1563 | * We implement the search by looking for an rbtree node that |
| 1564 | * immediately follows a suitable gap. That is, |
| 1565 | * - gap_start = vma->vm_prev->vm_end <= info->high_limit - length; |
| 1566 | * - gap_end = vma->vm_start >= info->low_limit + length; |
| 1567 | * - gap_end - gap_start >= length |
| 1568 | */ |
| 1569 | |
| 1570 | struct mm_struct *mm = current->mm; |
| 1571 | struct vm_area_struct *vma; |
| 1572 | unsigned long length, low_limit, high_limit, gap_start, gap_end; |
| 1573 | |
| 1574 | /* Adjust search length to account for worst case alignment overhead */ |
| 1575 | length = info->length + info->align_mask; |
| 1576 | if (length < info->length) |
| 1577 | return -ENOMEM; |
| 1578 | |
| 1579 | /* Adjust search limits by the desired length */ |
| 1580 | if (info->high_limit < length) |
| 1581 | return -ENOMEM; |
| 1582 | high_limit = info->high_limit - length; |
| 1583 | |
| 1584 | if (info->low_limit > high_limit) |
| 1585 | return -ENOMEM; |
| 1586 | low_limit = info->low_limit + length; |
| 1587 | |
| 1588 | /* Check if rbtree root looks promising */ |
| 1589 | if (RB_EMPTY_ROOT(&mm->mm_rb)) |
| 1590 | goto check_highest; |
| 1591 | vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb); |
| 1592 | if (vma->rb_subtree_gap < length) |
| 1593 | goto check_highest; |
| 1594 | |
| 1595 | while (true) { |
| 1596 | /* Visit left subtree if it looks promising */ |
| 1597 | gap_end = vma->vm_start; |
| 1598 | if (gap_end >= low_limit && vma->vm_rb.rb_left) { |
| 1599 | struct vm_area_struct *left = |
| 1600 | rb_entry(vma->vm_rb.rb_left, |
| 1601 | struct vm_area_struct, vm_rb); |
| 1602 | if (left->rb_subtree_gap >= length) { |
| 1603 | vma = left; |
| 1604 | continue; |
| 1605 | } |
| 1606 | } |
| 1607 | |
| 1608 | gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0; |
| 1609 | check_current: |
| 1610 | /* Check if current node has a suitable gap */ |
| 1611 | if (gap_start > high_limit) |
| 1612 | return -ENOMEM; |
| 1613 | if (gap_end >= low_limit && gap_end - gap_start >= length) |
| 1614 | goto found; |
| 1615 | |
| 1616 | /* Visit right subtree if it looks promising */ |
| 1617 | if (vma->vm_rb.rb_right) { |
| 1618 | struct vm_area_struct *right = |
| 1619 | rb_entry(vma->vm_rb.rb_right, |
| 1620 | struct vm_area_struct, vm_rb); |
| 1621 | if (right->rb_subtree_gap >= length) { |
| 1622 | vma = right; |
| 1623 | continue; |
| 1624 | } |
| 1625 | } |
| 1626 | |
| 1627 | /* Go back up the rbtree to find next candidate node */ |
| 1628 | while (true) { |
| 1629 | struct rb_node *prev = &vma->vm_rb; |
| 1630 | if (!rb_parent(prev)) |
| 1631 | goto check_highest; |
| 1632 | vma = rb_entry(rb_parent(prev), |
| 1633 | struct vm_area_struct, vm_rb); |
| 1634 | if (prev == vma->vm_rb.rb_left) { |
| 1635 | gap_start = vma->vm_prev->vm_end; |
| 1636 | gap_end = vma->vm_start; |
| 1637 | goto check_current; |
| 1638 | } |
| 1639 | } |
| 1640 | } |
| 1641 | |
| 1642 | check_highest: |
| 1643 | /* Check highest gap, which does not precede any rbtree node */ |
| 1644 | gap_start = mm->highest_vm_end; |
| 1645 | gap_end = ULONG_MAX; /* Only for VM_BUG_ON below */ |
| 1646 | if (gap_start > high_limit) |
| 1647 | return -ENOMEM; |
| 1648 | |
| 1649 | found: |
| 1650 | /* We found a suitable gap. Clip it with the original low_limit. */ |
| 1651 | if (gap_start < info->low_limit) |
| 1652 | gap_start = info->low_limit; |
| 1653 | |
| 1654 | /* Adjust gap address to the desired alignment */ |
| 1655 | gap_start += (info->align_offset - gap_start) & info->align_mask; |
| 1656 | |
| 1657 | VM_BUG_ON(gap_start + info->length > info->high_limit); |
| 1658 | VM_BUG_ON(gap_start + info->length > gap_end); |
| 1659 | return gap_start; |
| 1660 | } |
| 1661 | |
| 1662 | unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info) |
| 1663 | { |
| 1664 | struct mm_struct *mm = current->mm; |
| 1665 | struct vm_area_struct *vma; |
| 1666 | unsigned long length, low_limit, high_limit, gap_start, gap_end; |
| 1667 | |
| 1668 | /* Adjust search length to account for worst case alignment overhead */ |
| 1669 | length = info->length + info->align_mask; |
| 1670 | if (length < info->length) |
| 1671 | return -ENOMEM; |
| 1672 | |
| 1673 | /* |
| 1674 | * Adjust search limits by the desired length. |
| 1675 | * See implementation comment at top of unmapped_area(). |
| 1676 | */ |
| 1677 | gap_end = info->high_limit; |
| 1678 | if (gap_end < length) |
| 1679 | return -ENOMEM; |
| 1680 | high_limit = gap_end - length; |
| 1681 | |
| 1682 | if (info->low_limit > high_limit) |
| 1683 | return -ENOMEM; |
| 1684 | low_limit = info->low_limit + length; |
| 1685 | |
| 1686 | /* Check highest gap, which does not precede any rbtree node */ |
| 1687 | gap_start = mm->highest_vm_end; |
| 1688 | if (gap_start <= high_limit) |
| 1689 | goto found_highest; |
| 1690 | |
| 1691 | /* Check if rbtree root looks promising */ |
| 1692 | if (RB_EMPTY_ROOT(&mm->mm_rb)) |
| 1693 | return -ENOMEM; |
| 1694 | vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb); |
| 1695 | if (vma->rb_subtree_gap < length) |
| 1696 | return -ENOMEM; |
| 1697 | |
| 1698 | while (true) { |
| 1699 | /* Visit right subtree if it looks promising */ |
| 1700 | gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0; |
| 1701 | if (gap_start <= high_limit && vma->vm_rb.rb_right) { |
| 1702 | struct vm_area_struct *right = |
| 1703 | rb_entry(vma->vm_rb.rb_right, |
| 1704 | struct vm_area_struct, vm_rb); |
| 1705 | if (right->rb_subtree_gap >= length) { |
| 1706 | vma = right; |
| 1707 | continue; |
| 1708 | } |
| 1709 | } |
| 1710 | |
| 1711 | check_current: |
| 1712 | /* Check if current node has a suitable gap */ |
| 1713 | gap_end = vma->vm_start; |
| 1714 | if (gap_end < low_limit) |
| 1715 | return -ENOMEM; |
| 1716 | if (gap_start <= high_limit && gap_end - gap_start >= length) |
| 1717 | goto found; |
| 1718 | |
| 1719 | /* Visit left subtree if it looks promising */ |
| 1720 | if (vma->vm_rb.rb_left) { |
| 1721 | struct vm_area_struct *left = |
| 1722 | rb_entry(vma->vm_rb.rb_left, |
| 1723 | struct vm_area_struct, vm_rb); |
| 1724 | if (left->rb_subtree_gap >= length) { |
| 1725 | vma = left; |
| 1726 | continue; |
| 1727 | } |
| 1728 | } |
| 1729 | |
| 1730 | /* Go back up the rbtree to find next candidate node */ |
| 1731 | while (true) { |
| 1732 | struct rb_node *prev = &vma->vm_rb; |
| 1733 | if (!rb_parent(prev)) |
| 1734 | return -ENOMEM; |
| 1735 | vma = rb_entry(rb_parent(prev), |
| 1736 | struct vm_area_struct, vm_rb); |
| 1737 | if (prev == vma->vm_rb.rb_right) { |
| 1738 | gap_start = vma->vm_prev ? |
| 1739 | vma->vm_prev->vm_end : 0; |
| 1740 | goto check_current; |
| 1741 | } |
| 1742 | } |
| 1743 | } |
| 1744 | |
| 1745 | found: |
| 1746 | /* We found a suitable gap. Clip it with the original high_limit. */ |
| 1747 | if (gap_end > info->high_limit) |
| 1748 | gap_end = info->high_limit; |
| 1749 | |
| 1750 | found_highest: |
| 1751 | /* Compute highest gap address at the desired alignment */ |
| 1752 | gap_end -= info->length; |
| 1753 | gap_end -= (gap_end - info->align_offset) & info->align_mask; |
| 1754 | |
| 1755 | VM_BUG_ON(gap_end < info->low_limit); |
| 1756 | VM_BUG_ON(gap_end < gap_start); |
| 1757 | return gap_end; |
| 1758 | } |
| 1759 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1760 | /* Get an address range which is currently unmapped. |
| 1761 | * For shmat() with addr=0. |
| 1762 | * |
| 1763 | * Ugly calling convention alert: |
| 1764 | * Return value with the low bits set means error value, |
| 1765 | * ie |
| 1766 | * if (ret & ~PAGE_MASK) |
| 1767 | * error = ret; |
| 1768 | * |
| 1769 | * This function "knows" that -ENOMEM has the bits set. |
| 1770 | */ |
| 1771 | #ifndef HAVE_ARCH_UNMAPPED_AREA |
| 1772 | unsigned long |
| 1773 | arch_get_unmapped_area(struct file *filp, unsigned long addr, |
| 1774 | unsigned long len, unsigned long pgoff, unsigned long flags) |
| 1775 | { |
| 1776 | struct mm_struct *mm = current->mm; |
| 1777 | struct vm_area_struct *vma; |
Michel Lespinasse | db4fbfb | 2012-12-11 16:01:49 -0800 | [diff] [blame] | 1778 | struct vm_unmapped_area_info info; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1779 | |
| 1780 | if (len > TASK_SIZE) |
| 1781 | return -ENOMEM; |
| 1782 | |
Benjamin Herrenschmidt | 06abdfb | 2007-05-06 14:50:13 -0700 | [diff] [blame] | 1783 | if (flags & MAP_FIXED) |
| 1784 | return addr; |
| 1785 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1786 | if (addr) { |
| 1787 | addr = PAGE_ALIGN(addr); |
| 1788 | vma = find_vma(mm, addr); |
| 1789 | if (TASK_SIZE - len >= addr && |
| 1790 | (!vma || addr + len <= vma->vm_start)) |
| 1791 | return addr; |
| 1792 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1793 | |
Michel Lespinasse | db4fbfb | 2012-12-11 16:01:49 -0800 | [diff] [blame] | 1794 | info.flags = 0; |
| 1795 | info.length = len; |
| 1796 | info.low_limit = TASK_UNMAPPED_BASE; |
| 1797 | info.high_limit = TASK_SIZE; |
| 1798 | info.align_mask = 0; |
| 1799 | return vm_unmapped_area(&info); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1800 | } |
| 1801 | #endif |
| 1802 | |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 1803 | void arch_unmap_area(struct mm_struct *mm, unsigned long addr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1804 | { |
| 1805 | /* |
| 1806 | * Is this a new hole at the lowest possible address? |
| 1807 | */ |
Xiao Guangrong | f44d219 | 2012-03-21 16:33:56 -0700 | [diff] [blame] | 1808 | if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 1809 | mm->free_area_cache = addr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1810 | } |
| 1811 | |
| 1812 | /* |
| 1813 | * This mmap-allocator allocates new areas top-down from below the |
| 1814 | * stack's low limit (the base): |
| 1815 | */ |
| 1816 | #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN |
| 1817 | unsigned long |
| 1818 | arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, |
| 1819 | const unsigned long len, const unsigned long pgoff, |
| 1820 | const unsigned long flags) |
| 1821 | { |
| 1822 | struct vm_area_struct *vma; |
| 1823 | struct mm_struct *mm = current->mm; |
Michel Lespinasse | db4fbfb | 2012-12-11 16:01:49 -0800 | [diff] [blame] | 1824 | unsigned long addr = addr0; |
| 1825 | struct vm_unmapped_area_info info; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1826 | |
| 1827 | /* requested length too big for entire address space */ |
| 1828 | if (len > TASK_SIZE) |
| 1829 | return -ENOMEM; |
| 1830 | |
Benjamin Herrenschmidt | 06abdfb | 2007-05-06 14:50:13 -0700 | [diff] [blame] | 1831 | if (flags & MAP_FIXED) |
| 1832 | return addr; |
| 1833 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1834 | /* requesting a specific address */ |
| 1835 | if (addr) { |
| 1836 | addr = PAGE_ALIGN(addr); |
| 1837 | vma = find_vma(mm, addr); |
| 1838 | if (TASK_SIZE - len >= addr && |
| 1839 | (!vma || addr + len <= vma->vm_start)) |
| 1840 | return addr; |
| 1841 | } |
| 1842 | |
Michel Lespinasse | db4fbfb | 2012-12-11 16:01:49 -0800 | [diff] [blame] | 1843 | info.flags = VM_UNMAPPED_AREA_TOPDOWN; |
| 1844 | info.length = len; |
| 1845 | info.low_limit = PAGE_SIZE; |
| 1846 | info.high_limit = mm->mmap_base; |
| 1847 | info.align_mask = 0; |
| 1848 | addr = vm_unmapped_area(&info); |
Xiao Guangrong | b716ad9 | 2012-03-21 16:33:56 -0700 | [diff] [blame] | 1849 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1850 | /* |
| 1851 | * A failed mmap() very likely causes application failure, |
| 1852 | * so fall back to the bottom-up function here. This scenario |
| 1853 | * can happen with large stack limits and large mmap() |
| 1854 | * allocations. |
| 1855 | */ |
Michel Lespinasse | db4fbfb | 2012-12-11 16:01:49 -0800 | [diff] [blame] | 1856 | if (addr & ~PAGE_MASK) { |
| 1857 | VM_BUG_ON(addr != -ENOMEM); |
| 1858 | info.flags = 0; |
| 1859 | info.low_limit = TASK_UNMAPPED_BASE; |
| 1860 | info.high_limit = TASK_SIZE; |
| 1861 | addr = vm_unmapped_area(&info); |
| 1862 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1863 | |
| 1864 | return addr; |
| 1865 | } |
| 1866 | #endif |
| 1867 | |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 1868 | void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1869 | { |
| 1870 | /* |
| 1871 | * Is this a new hole at the highest possible address? |
| 1872 | */ |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 1873 | if (addr > mm->free_area_cache) |
| 1874 | mm->free_area_cache = addr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1875 | |
| 1876 | /* dont allow allocations above current base */ |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 1877 | if (mm->free_area_cache > mm->mmap_base) |
| 1878 | mm->free_area_cache = mm->mmap_base; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1879 | } |
| 1880 | |
| 1881 | unsigned long |
| 1882 | get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, |
| 1883 | unsigned long pgoff, unsigned long flags) |
| 1884 | { |
Benjamin Herrenschmidt | 06abdfb | 2007-05-06 14:50:13 -0700 | [diff] [blame] | 1885 | unsigned long (*get_area)(struct file *, unsigned long, |
| 1886 | unsigned long, unsigned long, unsigned long); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1887 | |
Al Viro | 9206de9 | 2009-12-03 15:23:11 -0500 | [diff] [blame] | 1888 | unsigned long error = arch_mmap_check(addr, len, flags); |
| 1889 | if (error) |
| 1890 | return error; |
| 1891 | |
| 1892 | /* Careful about overflows.. */ |
| 1893 | if (len > TASK_SIZE) |
| 1894 | return -ENOMEM; |
| 1895 | |
Benjamin Herrenschmidt | 06abdfb | 2007-05-06 14:50:13 -0700 | [diff] [blame] | 1896 | get_area = current->mm->get_unmapped_area; |
| 1897 | if (file && file->f_op && file->f_op->get_unmapped_area) |
| 1898 | get_area = file->f_op->get_unmapped_area; |
| 1899 | addr = get_area(file, addr, len, pgoff, flags); |
| 1900 | if (IS_ERR_VALUE(addr)) |
| 1901 | return addr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1902 | |
Linus Torvalds | 07ab67c | 2005-05-19 22:43:37 -0700 | [diff] [blame] | 1903 | if (addr > TASK_SIZE - len) |
| 1904 | return -ENOMEM; |
| 1905 | if (addr & ~PAGE_MASK) |
| 1906 | return -EINVAL; |
Benjamin Herrenschmidt | 06abdfb | 2007-05-06 14:50:13 -0700 | [diff] [blame] | 1907 | |
Al Viro | 9ac4ed4 | 2012-05-30 17:13:15 -0400 | [diff] [blame] | 1908 | addr = arch_rebalance_pgtables(addr, len); |
| 1909 | error = security_mmap_addr(addr); |
| 1910 | return error ? error : addr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1911 | } |
| 1912 | |
| 1913 | EXPORT_SYMBOL(get_unmapped_area); |
| 1914 | |
| 1915 | /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */ |
ZhenwenXu | 48aae42 | 2009-01-06 14:40:21 -0800 | [diff] [blame] | 1916 | struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1917 | { |
| 1918 | struct vm_area_struct *vma = NULL; |
| 1919 | |
Rajman Mekaco | 841e31e | 2012-05-29 15:06:21 -0700 | [diff] [blame] | 1920 | if (WARN_ON_ONCE(!mm)) /* Remove this in linux-3.6 */ |
| 1921 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1922 | |
Rajman Mekaco | 841e31e | 2012-05-29 15:06:21 -0700 | [diff] [blame] | 1923 | /* Check the cache first. */ |
| 1924 | /* (Cache hit rate is typically around 35%.) */ |
| 1925 | vma = mm->mmap_cache; |
| 1926 | if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) { |
| 1927 | struct rb_node *rb_node; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1928 | |
Rajman Mekaco | 841e31e | 2012-05-29 15:06:21 -0700 | [diff] [blame] | 1929 | rb_node = mm->mm_rb.rb_node; |
| 1930 | vma = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1931 | |
Rajman Mekaco | 841e31e | 2012-05-29 15:06:21 -0700 | [diff] [blame] | 1932 | while (rb_node) { |
| 1933 | struct vm_area_struct *vma_tmp; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1934 | |
Rajman Mekaco | 841e31e | 2012-05-29 15:06:21 -0700 | [diff] [blame] | 1935 | vma_tmp = rb_entry(rb_node, |
| 1936 | struct vm_area_struct, vm_rb); |
| 1937 | |
| 1938 | if (vma_tmp->vm_end > addr) { |
| 1939 | vma = vma_tmp; |
| 1940 | if (vma_tmp->vm_start <= addr) |
| 1941 | break; |
| 1942 | rb_node = rb_node->rb_left; |
| 1943 | } else |
| 1944 | rb_node = rb_node->rb_right; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1945 | } |
Rajman Mekaco | 841e31e | 2012-05-29 15:06:21 -0700 | [diff] [blame] | 1946 | if (vma) |
| 1947 | mm->mmap_cache = vma; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1948 | } |
| 1949 | return vma; |
| 1950 | } |
| 1951 | |
| 1952 | EXPORT_SYMBOL(find_vma); |
| 1953 | |
KOSAKI Motohiro | 6bd4837 | 2012-01-10 15:08:07 -0800 | [diff] [blame] | 1954 | /* |
| 1955 | * Same as find_vma, but also return a pointer to the previous VMA in *pprev. |
KOSAKI Motohiro | 6bd4837 | 2012-01-10 15:08:07 -0800 | [diff] [blame] | 1956 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1957 | struct vm_area_struct * |
| 1958 | find_vma_prev(struct mm_struct *mm, unsigned long addr, |
| 1959 | struct vm_area_struct **pprev) |
| 1960 | { |
KOSAKI Motohiro | 6bd4837 | 2012-01-10 15:08:07 -0800 | [diff] [blame] | 1961 | struct vm_area_struct *vma; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1962 | |
KOSAKI Motohiro | 6bd4837 | 2012-01-10 15:08:07 -0800 | [diff] [blame] | 1963 | vma = find_vma(mm, addr); |
Mikulas Patocka | 83cd904 | 2012-03-04 19:52:03 -0500 | [diff] [blame] | 1964 | if (vma) { |
| 1965 | *pprev = vma->vm_prev; |
| 1966 | } else { |
| 1967 | struct rb_node *rb_node = mm->mm_rb.rb_node; |
| 1968 | *pprev = NULL; |
| 1969 | while (rb_node) { |
| 1970 | *pprev = rb_entry(rb_node, struct vm_area_struct, vm_rb); |
| 1971 | rb_node = rb_node->rb_right; |
| 1972 | } |
| 1973 | } |
KOSAKI Motohiro | 6bd4837 | 2012-01-10 15:08:07 -0800 | [diff] [blame] | 1974 | return vma; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1975 | } |
| 1976 | |
| 1977 | /* |
| 1978 | * Verify that the stack growth is acceptable and |
| 1979 | * update accounting. This is shared with both the |
| 1980 | * grow-up and grow-down cases. |
| 1981 | */ |
ZhenwenXu | 48aae42 | 2009-01-06 14:40:21 -0800 | [diff] [blame] | 1982 | static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1983 | { |
| 1984 | struct mm_struct *mm = vma->vm_mm; |
| 1985 | struct rlimit *rlim = current->signal->rlim; |
Adam Litke | 0d59a01 | 2007-01-30 14:35:39 -0800 | [diff] [blame] | 1986 | unsigned long new_start; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1987 | |
| 1988 | /* address space limit tests */ |
akpm@osdl.org | 119f657 | 2005-05-01 08:58:35 -0700 | [diff] [blame] | 1989 | if (!may_expand_vm(mm, grow)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1990 | return -ENOMEM; |
| 1991 | |
| 1992 | /* Stack limit test */ |
Jiri Slaby | 59e99e5 | 2010-03-05 13:41:44 -0800 | [diff] [blame] | 1993 | if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1994 | return -ENOMEM; |
| 1995 | |
| 1996 | /* mlock limit tests */ |
| 1997 | if (vma->vm_flags & VM_LOCKED) { |
| 1998 | unsigned long locked; |
| 1999 | unsigned long limit; |
| 2000 | locked = mm->locked_vm + grow; |
Jiri Slaby | 59e99e5 | 2010-03-05 13:41:44 -0800 | [diff] [blame] | 2001 | limit = ACCESS_ONCE(rlim[RLIMIT_MEMLOCK].rlim_cur); |
| 2002 | limit >>= PAGE_SHIFT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2003 | if (locked > limit && !capable(CAP_IPC_LOCK)) |
| 2004 | return -ENOMEM; |
| 2005 | } |
| 2006 | |
Adam Litke | 0d59a01 | 2007-01-30 14:35:39 -0800 | [diff] [blame] | 2007 | /* Check to ensure the stack will not grow into a hugetlb-only region */ |
| 2008 | new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start : |
| 2009 | vma->vm_end - size; |
| 2010 | if (is_hugepage_only_range(vma->vm_mm, new_start, size)) |
| 2011 | return -EFAULT; |
| 2012 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2013 | /* |
| 2014 | * Overcommit.. This must be the final test, as it will |
| 2015 | * update security statistics. |
| 2016 | */ |
Hugh Dickins | 05fa199 | 2009-04-16 21:58:12 +0100 | [diff] [blame] | 2017 | if (security_vm_enough_memory_mm(mm, grow)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2018 | return -ENOMEM; |
| 2019 | |
| 2020 | /* Ok, everything looks good - let it rip */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2021 | if (vma->vm_flags & VM_LOCKED) |
| 2022 | mm->locked_vm += grow; |
Hugh Dickins | ab50b8e | 2005-10-29 18:15:56 -0700 | [diff] [blame] | 2023 | vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2024 | return 0; |
| 2025 | } |
| 2026 | |
Hugh Dickins | 46dea3d | 2005-10-29 18:16:20 -0700 | [diff] [blame] | 2027 | #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2028 | /* |
Hugh Dickins | 46dea3d | 2005-10-29 18:16:20 -0700 | [diff] [blame] | 2029 | * PA-RISC uses this for its stack; IA64 for its Register Backing Store. |
| 2030 | * vma is the last one with address > vma->vm_end. Have to extend vma. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2031 | */ |
Hugh Dickins | 46dea3d | 2005-10-29 18:16:20 -0700 | [diff] [blame] | 2032 | int expand_upwards(struct vm_area_struct *vma, unsigned long address) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2033 | { |
| 2034 | int error; |
| 2035 | |
| 2036 | if (!(vma->vm_flags & VM_GROWSUP)) |
| 2037 | return -EFAULT; |
| 2038 | |
| 2039 | /* |
| 2040 | * We must make sure the anon_vma is allocated |
| 2041 | * so that the anon_vma locking is not a noop. |
| 2042 | */ |
| 2043 | if (unlikely(anon_vma_prepare(vma))) |
| 2044 | return -ENOMEM; |
Rik van Riel | bb4a340 | 2010-08-09 17:18:37 -0700 | [diff] [blame] | 2045 | vma_lock_anon_vma(vma); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2046 | |
| 2047 | /* |
| 2048 | * vma->vm_start/vm_end cannot change under us because the caller |
| 2049 | * is required to hold the mmap_sem in read mode. We need the |
| 2050 | * anon_vma lock to serialize against concurrent expand_stacks. |
Helge Deller | 06b32f3 | 2006-12-19 19:28:33 +0100 | [diff] [blame] | 2051 | * Also guard against wrapping around to address 0. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2052 | */ |
Helge Deller | 06b32f3 | 2006-12-19 19:28:33 +0100 | [diff] [blame] | 2053 | if (address < PAGE_ALIGN(address+4)) |
| 2054 | address = PAGE_ALIGN(address+4); |
| 2055 | else { |
Rik van Riel | bb4a340 | 2010-08-09 17:18:37 -0700 | [diff] [blame] | 2056 | vma_unlock_anon_vma(vma); |
Helge Deller | 06b32f3 | 2006-12-19 19:28:33 +0100 | [diff] [blame] | 2057 | return -ENOMEM; |
| 2058 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2059 | error = 0; |
| 2060 | |
| 2061 | /* Somebody else might have raced and expanded it already */ |
| 2062 | if (address > vma->vm_end) { |
| 2063 | unsigned long size, grow; |
| 2064 | |
| 2065 | size = address - vma->vm_start; |
| 2066 | grow = (address - vma->vm_end) >> PAGE_SHIFT; |
| 2067 | |
Hugh Dickins | 42c36f6 | 2011-05-09 17:44:42 -0700 | [diff] [blame] | 2068 | error = -ENOMEM; |
| 2069 | if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) { |
| 2070 | error = acct_stack_growth(vma, size, grow); |
| 2071 | if (!error) { |
Michel Lespinasse | 4128997 | 2012-12-12 13:52:25 -0800 | [diff] [blame] | 2072 | /* |
| 2073 | * vma_gap_update() doesn't support concurrent |
| 2074 | * updates, but we only hold a shared mmap_sem |
| 2075 | * lock here, so we need to protect against |
| 2076 | * concurrent vma expansions. |
| 2077 | * vma_lock_anon_vma() doesn't help here, as |
| 2078 | * we don't guarantee that all growable vmas |
| 2079 | * in a mm share the same root anon vma. |
| 2080 | * So, we reuse mm->page_table_lock to guard |
| 2081 | * against concurrent vma expansions. |
| 2082 | */ |
| 2083 | spin_lock(&vma->vm_mm->page_table_lock); |
Michel Lespinasse | bf181b9 | 2012-10-08 16:31:39 -0700 | [diff] [blame] | 2084 | anon_vma_interval_tree_pre_update_vma(vma); |
Hugh Dickins | 42c36f6 | 2011-05-09 17:44:42 -0700 | [diff] [blame] | 2085 | vma->vm_end = address; |
Michel Lespinasse | bf181b9 | 2012-10-08 16:31:39 -0700 | [diff] [blame] | 2086 | anon_vma_interval_tree_post_update_vma(vma); |
Michel Lespinasse | d373718 | 2012-12-11 16:01:38 -0800 | [diff] [blame] | 2087 | if (vma->vm_next) |
| 2088 | vma_gap_update(vma->vm_next); |
| 2089 | else |
| 2090 | vma->vm_mm->highest_vm_end = address; |
Michel Lespinasse | 4128997 | 2012-12-12 13:52:25 -0800 | [diff] [blame] | 2091 | spin_unlock(&vma->vm_mm->page_table_lock); |
| 2092 | |
Hugh Dickins | 42c36f6 | 2011-05-09 17:44:42 -0700 | [diff] [blame] | 2093 | perf_event_mmap(vma); |
| 2094 | } |
Eric B Munson | 3af9e85 | 2010-05-18 15:30:49 +0100 | [diff] [blame] | 2095 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2096 | } |
Rik van Riel | bb4a340 | 2010-08-09 17:18:37 -0700 | [diff] [blame] | 2097 | vma_unlock_anon_vma(vma); |
Andrea Arcangeli | b15d00b | 2011-01-13 15:46:59 -0800 | [diff] [blame] | 2098 | khugepaged_enter_vma_merge(vma); |
Michel Lespinasse | ed8ea81 | 2012-10-08 16:31:45 -0700 | [diff] [blame] | 2099 | validate_mm(vma->vm_mm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2100 | return error; |
| 2101 | } |
Hugh Dickins | 46dea3d | 2005-10-29 18:16:20 -0700 | [diff] [blame] | 2102 | #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */ |
| 2103 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2104 | /* |
| 2105 | * vma is the first one with address < vma->vm_start. Have to extend vma. |
| 2106 | */ |
Michal Hocko | d05f316 | 2011-05-24 17:11:44 -0700 | [diff] [blame] | 2107 | int expand_downwards(struct vm_area_struct *vma, |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 2108 | unsigned long address) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2109 | { |
| 2110 | int error; |
| 2111 | |
| 2112 | /* |
| 2113 | * We must make sure the anon_vma is allocated |
| 2114 | * so that the anon_vma locking is not a noop. |
| 2115 | */ |
| 2116 | if (unlikely(anon_vma_prepare(vma))) |
| 2117 | return -ENOMEM; |
Eric Paris | 8869477 | 2007-11-26 18:47:26 -0500 | [diff] [blame] | 2118 | |
| 2119 | address &= PAGE_MASK; |
Al Viro | e546785 | 2012-05-30 13:30:51 -0400 | [diff] [blame] | 2120 | error = security_mmap_addr(address); |
Eric Paris | 8869477 | 2007-11-26 18:47:26 -0500 | [diff] [blame] | 2121 | if (error) |
| 2122 | return error; |
| 2123 | |
Rik van Riel | bb4a340 | 2010-08-09 17:18:37 -0700 | [diff] [blame] | 2124 | vma_lock_anon_vma(vma); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2125 | |
| 2126 | /* |
| 2127 | * vma->vm_start/vm_end cannot change under us because the caller |
| 2128 | * is required to hold the mmap_sem in read mode. We need the |
| 2129 | * anon_vma lock to serialize against concurrent expand_stacks. |
| 2130 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2131 | |
| 2132 | /* Somebody else might have raced and expanded it already */ |
| 2133 | if (address < vma->vm_start) { |
| 2134 | unsigned long size, grow; |
| 2135 | |
| 2136 | size = vma->vm_end - address; |
| 2137 | grow = (vma->vm_start - address) >> PAGE_SHIFT; |
| 2138 | |
Linus Torvalds | a626ca6 | 2011-04-13 08:07:28 -0700 | [diff] [blame] | 2139 | error = -ENOMEM; |
| 2140 | if (grow <= vma->vm_pgoff) { |
| 2141 | error = acct_stack_growth(vma, size, grow); |
| 2142 | if (!error) { |
Michel Lespinasse | 4128997 | 2012-12-12 13:52:25 -0800 | [diff] [blame] | 2143 | /* |
| 2144 | * vma_gap_update() doesn't support concurrent |
| 2145 | * updates, but we only hold a shared mmap_sem |
| 2146 | * lock here, so we need to protect against |
| 2147 | * concurrent vma expansions. |
| 2148 | * vma_lock_anon_vma() doesn't help here, as |
| 2149 | * we don't guarantee that all growable vmas |
| 2150 | * in a mm share the same root anon vma. |
| 2151 | * So, we reuse mm->page_table_lock to guard |
| 2152 | * against concurrent vma expansions. |
| 2153 | */ |
| 2154 | spin_lock(&vma->vm_mm->page_table_lock); |
Michel Lespinasse | bf181b9 | 2012-10-08 16:31:39 -0700 | [diff] [blame] | 2155 | anon_vma_interval_tree_pre_update_vma(vma); |
Linus Torvalds | a626ca6 | 2011-04-13 08:07:28 -0700 | [diff] [blame] | 2156 | vma->vm_start = address; |
| 2157 | vma->vm_pgoff -= grow; |
Michel Lespinasse | bf181b9 | 2012-10-08 16:31:39 -0700 | [diff] [blame] | 2158 | anon_vma_interval_tree_post_update_vma(vma); |
Michel Lespinasse | d373718 | 2012-12-11 16:01:38 -0800 | [diff] [blame] | 2159 | vma_gap_update(vma); |
Michel Lespinasse | 4128997 | 2012-12-12 13:52:25 -0800 | [diff] [blame] | 2160 | spin_unlock(&vma->vm_mm->page_table_lock); |
| 2161 | |
Linus Torvalds | a626ca6 | 2011-04-13 08:07:28 -0700 | [diff] [blame] | 2162 | perf_event_mmap(vma); |
| 2163 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2164 | } |
| 2165 | } |
Rik van Riel | bb4a340 | 2010-08-09 17:18:37 -0700 | [diff] [blame] | 2166 | vma_unlock_anon_vma(vma); |
Andrea Arcangeli | b15d00b | 2011-01-13 15:46:59 -0800 | [diff] [blame] | 2167 | khugepaged_enter_vma_merge(vma); |
Michel Lespinasse | ed8ea81 | 2012-10-08 16:31:45 -0700 | [diff] [blame] | 2168 | validate_mm(vma->vm_mm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2169 | return error; |
| 2170 | } |
| 2171 | |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 2172 | #ifdef CONFIG_STACK_GROWSUP |
| 2173 | int expand_stack(struct vm_area_struct *vma, unsigned long address) |
| 2174 | { |
| 2175 | return expand_upwards(vma, address); |
| 2176 | } |
| 2177 | |
| 2178 | struct vm_area_struct * |
| 2179 | find_extend_vma(struct mm_struct *mm, unsigned long addr) |
| 2180 | { |
| 2181 | struct vm_area_struct *vma, *prev; |
| 2182 | |
| 2183 | addr &= PAGE_MASK; |
| 2184 | vma = find_vma_prev(mm, addr, &prev); |
| 2185 | if (vma && (vma->vm_start <= addr)) |
| 2186 | return vma; |
Denys Vlasenko | 1c12718 | 2008-11-12 01:24:41 +0100 | [diff] [blame] | 2187 | if (!prev || expand_stack(prev, addr)) |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 2188 | return NULL; |
Rik van Riel | ba470de | 2008-10-18 20:26:50 -0700 | [diff] [blame] | 2189 | if (prev->vm_flags & VM_LOCKED) { |
KOSAKI Motohiro | c58267c | 2010-03-05 13:41:43 -0800 | [diff] [blame] | 2190 | mlock_vma_pages_range(prev, addr, prev->vm_end); |
Rik van Riel | ba470de | 2008-10-18 20:26:50 -0700 | [diff] [blame] | 2191 | } |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 2192 | return prev; |
| 2193 | } |
| 2194 | #else |
| 2195 | int expand_stack(struct vm_area_struct *vma, unsigned long address) |
| 2196 | { |
| 2197 | return expand_downwards(vma, address); |
| 2198 | } |
| 2199 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2200 | struct vm_area_struct * |
| 2201 | find_extend_vma(struct mm_struct * mm, unsigned long addr) |
| 2202 | { |
| 2203 | struct vm_area_struct * vma; |
| 2204 | unsigned long start; |
| 2205 | |
| 2206 | addr &= PAGE_MASK; |
| 2207 | vma = find_vma(mm,addr); |
| 2208 | if (!vma) |
| 2209 | return NULL; |
| 2210 | if (vma->vm_start <= addr) |
| 2211 | return vma; |
| 2212 | if (!(vma->vm_flags & VM_GROWSDOWN)) |
| 2213 | return NULL; |
| 2214 | start = vma->vm_start; |
| 2215 | if (expand_stack(vma, addr)) |
| 2216 | return NULL; |
Rik van Riel | ba470de | 2008-10-18 20:26:50 -0700 | [diff] [blame] | 2217 | if (vma->vm_flags & VM_LOCKED) { |
KOSAKI Motohiro | c58267c | 2010-03-05 13:41:43 -0800 | [diff] [blame] | 2218 | mlock_vma_pages_range(vma, addr, start); |
Rik van Riel | ba470de | 2008-10-18 20:26:50 -0700 | [diff] [blame] | 2219 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2220 | return vma; |
| 2221 | } |
| 2222 | #endif |
| 2223 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2224 | /* |
Hugh Dickins | 2c0b381 | 2005-10-29 18:15:56 -0700 | [diff] [blame] | 2225 | * Ok - we have the memory areas we should free on the vma list, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2226 | * so release them, and do the vma updates. |
Hugh Dickins | 2c0b381 | 2005-10-29 18:15:56 -0700 | [diff] [blame] | 2227 | * |
| 2228 | * Called with the mm semaphore held. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2229 | */ |
Hugh Dickins | 2c0b381 | 2005-10-29 18:15:56 -0700 | [diff] [blame] | 2230 | static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2231 | { |
Linus Torvalds | 4f74d2c | 2012-05-06 13:54:06 -0700 | [diff] [blame] | 2232 | unsigned long nr_accounted = 0; |
| 2233 | |
Hugh Dickins | 365e9c87 | 2005-10-29 18:16:18 -0700 | [diff] [blame] | 2234 | /* Update high watermark before we lower total_vm */ |
| 2235 | update_hiwater_vm(mm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2236 | do { |
Hugh Dickins | 2c0b381 | 2005-10-29 18:15:56 -0700 | [diff] [blame] | 2237 | long nrpages = vma_pages(vma); |
| 2238 | |
Linus Torvalds | 4f74d2c | 2012-05-06 13:54:06 -0700 | [diff] [blame] | 2239 | if (vma->vm_flags & VM_ACCOUNT) |
| 2240 | nr_accounted += nrpages; |
Hugh Dickins | 2c0b381 | 2005-10-29 18:15:56 -0700 | [diff] [blame] | 2241 | vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages); |
Hugh Dickins | a8fb561 | 2005-10-29 18:15:57 -0700 | [diff] [blame] | 2242 | vma = remove_vma(vma); |
Hugh Dickins | 146425a | 2005-04-19 13:29:18 -0700 | [diff] [blame] | 2243 | } while (vma); |
Linus Torvalds | 4f74d2c | 2012-05-06 13:54:06 -0700 | [diff] [blame] | 2244 | vm_unacct_memory(nr_accounted); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2245 | validate_mm(mm); |
| 2246 | } |
| 2247 | |
| 2248 | /* |
| 2249 | * Get rid of page table information in the indicated region. |
| 2250 | * |
Paolo 'Blaisorblade' Giarrusso | f10df68 | 2005-09-21 09:55:37 -0700 | [diff] [blame] | 2251 | * Called with the mm semaphore held. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2252 | */ |
| 2253 | static void unmap_region(struct mm_struct *mm, |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 2254 | struct vm_area_struct *vma, struct vm_area_struct *prev, |
| 2255 | unsigned long start, unsigned long end) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2256 | { |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 2257 | struct vm_area_struct *next = prev? prev->vm_next: mm->mmap; |
Peter Zijlstra | d16dfc5 | 2011-05-24 17:11:45 -0700 | [diff] [blame] | 2258 | struct mmu_gather tlb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2259 | |
| 2260 | lru_add_drain(); |
Peter Zijlstra | d16dfc5 | 2011-05-24 17:11:45 -0700 | [diff] [blame] | 2261 | tlb_gather_mmu(&tlb, mm, 0); |
Hugh Dickins | 365e9c87 | 2005-10-29 18:16:18 -0700 | [diff] [blame] | 2262 | update_hiwater_rss(mm); |
Linus Torvalds | 4f74d2c | 2012-05-06 13:54:06 -0700 | [diff] [blame] | 2263 | unmap_vmas(&tlb, vma, start, end); |
Peter Zijlstra | d16dfc5 | 2011-05-24 17:11:45 -0700 | [diff] [blame] | 2264 | free_pgtables(&tlb, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS, |
| 2265 | next ? next->vm_start : 0); |
| 2266 | tlb_finish_mmu(&tlb, start, end); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2267 | } |
| 2268 | |
| 2269 | /* |
| 2270 | * Create a list of vma's touched by the unmap, removing them from the mm's |
| 2271 | * vma list as we go.. |
| 2272 | */ |
| 2273 | static void |
| 2274 | detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma, |
| 2275 | struct vm_area_struct *prev, unsigned long end) |
| 2276 | { |
| 2277 | struct vm_area_struct **insertion_point; |
| 2278 | struct vm_area_struct *tail_vma = NULL; |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 2279 | unsigned long addr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2280 | |
| 2281 | insertion_point = (prev ? &prev->vm_next : &mm->mmap); |
Linus Torvalds | 297c5ee | 2010-08-20 16:24:55 -0700 | [diff] [blame] | 2282 | vma->vm_prev = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2283 | do { |
Michel Lespinasse | d373718 | 2012-12-11 16:01:38 -0800 | [diff] [blame] | 2284 | vma_rb_erase(vma, &mm->mm_rb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2285 | mm->map_count--; |
| 2286 | tail_vma = vma; |
| 2287 | vma = vma->vm_next; |
| 2288 | } while (vma && vma->vm_start < end); |
| 2289 | *insertion_point = vma; |
Michel Lespinasse | d373718 | 2012-12-11 16:01:38 -0800 | [diff] [blame] | 2290 | if (vma) { |
Linus Torvalds | 297c5ee | 2010-08-20 16:24:55 -0700 | [diff] [blame] | 2291 | vma->vm_prev = prev; |
Michel Lespinasse | d373718 | 2012-12-11 16:01:38 -0800 | [diff] [blame] | 2292 | vma_gap_update(vma); |
| 2293 | } else |
| 2294 | mm->highest_vm_end = prev ? prev->vm_end : 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2295 | tail_vma->vm_next = NULL; |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 2296 | if (mm->unmap_area == arch_unmap_area) |
| 2297 | addr = prev ? prev->vm_end : mm->mmap_base; |
| 2298 | else |
| 2299 | addr = vma ? vma->vm_start : mm->mmap_base; |
| 2300 | mm->unmap_area(mm, addr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2301 | mm->mmap_cache = NULL; /* Kill the cache. */ |
| 2302 | } |
| 2303 | |
| 2304 | /* |
KOSAKI Motohiro | 659ace5 | 2009-12-14 17:57:56 -0800 | [diff] [blame] | 2305 | * __split_vma() bypasses sysctl_max_map_count checking. We use this on the |
| 2306 | * munmap path where it doesn't make sense to fail. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2307 | */ |
KOSAKI Motohiro | 659ace5 | 2009-12-14 17:57:56 -0800 | [diff] [blame] | 2308 | static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2309 | unsigned long addr, int new_below) |
| 2310 | { |
| 2311 | struct mempolicy *pol; |
| 2312 | struct vm_area_struct *new; |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 2313 | int err = -ENOMEM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2314 | |
Andi Kleen | a551643 | 2008-07-23 21:27:41 -0700 | [diff] [blame] | 2315 | if (is_vm_hugetlb_page(vma) && (addr & |
| 2316 | ~(huge_page_mask(hstate_vma(vma))))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2317 | return -EINVAL; |
| 2318 | |
Christoph Lameter | e94b176 | 2006-12-06 20:33:17 -0800 | [diff] [blame] | 2319 | new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2320 | if (!new) |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 2321 | goto out_err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2322 | |
| 2323 | /* most fields are the same, copy all, and then fixup */ |
| 2324 | *new = *vma; |
| 2325 | |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 2326 | INIT_LIST_HEAD(&new->anon_vma_chain); |
| 2327 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2328 | if (new_below) |
| 2329 | new->vm_end = addr; |
| 2330 | else { |
| 2331 | new->vm_start = addr; |
| 2332 | new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT); |
| 2333 | } |
| 2334 | |
Lee Schermerhorn | 846a16b | 2008-04-28 02:13:09 -0700 | [diff] [blame] | 2335 | pol = mpol_dup(vma_policy(vma)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2336 | if (IS_ERR(pol)) { |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 2337 | err = PTR_ERR(pol); |
| 2338 | goto out_free_vma; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2339 | } |
| 2340 | vma_set_policy(new, pol); |
| 2341 | |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 2342 | if (anon_vma_clone(new, vma)) |
| 2343 | goto out_free_mpol; |
| 2344 | |
Konstantin Khlebnikov | e9714ac | 2012-10-08 16:28:54 -0700 | [diff] [blame] | 2345 | if (new->vm_file) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2346 | get_file(new->vm_file); |
| 2347 | |
| 2348 | if (new->vm_ops && new->vm_ops->open) |
| 2349 | new->vm_ops->open(new); |
| 2350 | |
| 2351 | if (new_below) |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 2352 | err = vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff + |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2353 | ((addr - new->vm_start) >> PAGE_SHIFT), new); |
| 2354 | else |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 2355 | err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2356 | |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 2357 | /* Success. */ |
| 2358 | if (!err) |
| 2359 | return 0; |
| 2360 | |
| 2361 | /* Clean everything up if vma_adjust failed. */ |
Rik van Riel | 5892753 | 2010-04-26 12:33:03 -0400 | [diff] [blame] | 2362 | if (new->vm_ops && new->vm_ops->close) |
| 2363 | new->vm_ops->close(new); |
Konstantin Khlebnikov | e9714ac | 2012-10-08 16:28:54 -0700 | [diff] [blame] | 2364 | if (new->vm_file) |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 2365 | fput(new->vm_file); |
Andrea Arcangeli | 2aeadc3 | 2010-09-22 13:05:12 -0700 | [diff] [blame] | 2366 | unlink_anon_vmas(new); |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 2367 | out_free_mpol: |
| 2368 | mpol_put(pol); |
| 2369 | out_free_vma: |
| 2370 | kmem_cache_free(vm_area_cachep, new); |
| 2371 | out_err: |
| 2372 | return err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2373 | } |
| 2374 | |
KOSAKI Motohiro | 659ace5 | 2009-12-14 17:57:56 -0800 | [diff] [blame] | 2375 | /* |
| 2376 | * Split a vma into two pieces at address 'addr', a new vma is allocated |
| 2377 | * either for the first part or the tail. |
| 2378 | */ |
| 2379 | int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, |
| 2380 | unsigned long addr, int new_below) |
| 2381 | { |
| 2382 | if (mm->map_count >= sysctl_max_map_count) |
| 2383 | return -ENOMEM; |
| 2384 | |
| 2385 | return __split_vma(mm, vma, addr, new_below); |
| 2386 | } |
| 2387 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2388 | /* Munmap is split into 2 main parts -- this part which finds |
| 2389 | * what needs doing, and the areas themselves, which do the |
| 2390 | * work. This now handles partial unmappings. |
| 2391 | * Jeremy Fitzhardinge <jeremy@goop.org> |
| 2392 | */ |
| 2393 | int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) |
| 2394 | { |
| 2395 | unsigned long end; |
Hugh Dickins | 146425a | 2005-04-19 13:29:18 -0700 | [diff] [blame] | 2396 | struct vm_area_struct *vma, *prev, *last; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2397 | |
| 2398 | if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start) |
| 2399 | return -EINVAL; |
| 2400 | |
| 2401 | if ((len = PAGE_ALIGN(len)) == 0) |
| 2402 | return -EINVAL; |
| 2403 | |
| 2404 | /* Find the first overlapping VMA */ |
Linus Torvalds | 9be34c9 | 2011-06-16 00:35:09 -0700 | [diff] [blame] | 2405 | vma = find_vma(mm, start); |
Hugh Dickins | 146425a | 2005-04-19 13:29:18 -0700 | [diff] [blame] | 2406 | if (!vma) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2407 | return 0; |
Linus Torvalds | 9be34c9 | 2011-06-16 00:35:09 -0700 | [diff] [blame] | 2408 | prev = vma->vm_prev; |
Hugh Dickins | 146425a | 2005-04-19 13:29:18 -0700 | [diff] [blame] | 2409 | /* we have start < vma->vm_end */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2410 | |
| 2411 | /* if it doesn't overlap, we have nothing.. */ |
| 2412 | end = start + len; |
Hugh Dickins | 146425a | 2005-04-19 13:29:18 -0700 | [diff] [blame] | 2413 | if (vma->vm_start >= end) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2414 | return 0; |
| 2415 | |
| 2416 | /* |
| 2417 | * If we need to split any vma, do it now to save pain later. |
| 2418 | * |
| 2419 | * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially |
| 2420 | * unmapped vm_area_struct will remain in use: so lower split_vma |
| 2421 | * places tmp vma above, and higher split_vma places tmp vma below. |
| 2422 | */ |
Hugh Dickins | 146425a | 2005-04-19 13:29:18 -0700 | [diff] [blame] | 2423 | if (start > vma->vm_start) { |
KOSAKI Motohiro | 659ace5 | 2009-12-14 17:57:56 -0800 | [diff] [blame] | 2424 | int error; |
| 2425 | |
| 2426 | /* |
| 2427 | * Make sure that map_count on return from munmap() will |
| 2428 | * not exceed its limit; but let map_count go just above |
| 2429 | * its limit temporarily, to help free resources as expected. |
| 2430 | */ |
| 2431 | if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count) |
| 2432 | return -ENOMEM; |
| 2433 | |
| 2434 | error = __split_vma(mm, vma, start, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2435 | if (error) |
| 2436 | return error; |
Hugh Dickins | 146425a | 2005-04-19 13:29:18 -0700 | [diff] [blame] | 2437 | prev = vma; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2438 | } |
| 2439 | |
| 2440 | /* Does it split the last one? */ |
| 2441 | last = find_vma(mm, end); |
| 2442 | if (last && end > last->vm_start) { |
KOSAKI Motohiro | 659ace5 | 2009-12-14 17:57:56 -0800 | [diff] [blame] | 2443 | int error = __split_vma(mm, last, end, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2444 | if (error) |
| 2445 | return error; |
| 2446 | } |
Hugh Dickins | 146425a | 2005-04-19 13:29:18 -0700 | [diff] [blame] | 2447 | vma = prev? prev->vm_next: mm->mmap; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2448 | |
| 2449 | /* |
Rik van Riel | ba470de | 2008-10-18 20:26:50 -0700 | [diff] [blame] | 2450 | * unlock any mlock()ed ranges before detaching vmas |
| 2451 | */ |
| 2452 | if (mm->locked_vm) { |
| 2453 | struct vm_area_struct *tmp = vma; |
| 2454 | while (tmp && tmp->vm_start < end) { |
| 2455 | if (tmp->vm_flags & VM_LOCKED) { |
| 2456 | mm->locked_vm -= vma_pages(tmp); |
| 2457 | munlock_vma_pages_all(tmp); |
| 2458 | } |
| 2459 | tmp = tmp->vm_next; |
| 2460 | } |
| 2461 | } |
| 2462 | |
| 2463 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2464 | * Remove the vma's, and unmap the actual pages |
| 2465 | */ |
Hugh Dickins | 146425a | 2005-04-19 13:29:18 -0700 | [diff] [blame] | 2466 | detach_vmas_to_be_unmapped(mm, vma, prev, end); |
| 2467 | unmap_region(mm, vma, prev, start, end); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2468 | |
| 2469 | /* Fix up all other VM information */ |
Hugh Dickins | 2c0b381 | 2005-10-29 18:15:56 -0700 | [diff] [blame] | 2470 | remove_vma_list(mm, vma); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2471 | |
| 2472 | return 0; |
| 2473 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2474 | |
Al Viro | bfce281 | 2012-04-20 21:57:04 -0400 | [diff] [blame] | 2475 | int vm_munmap(unsigned long start, size_t len) |
Linus Torvalds | a46ef99 | 2012-04-20 16:20:01 -0700 | [diff] [blame] | 2476 | { |
| 2477 | int ret; |
Al Viro | bfce281 | 2012-04-20 21:57:04 -0400 | [diff] [blame] | 2478 | struct mm_struct *mm = current->mm; |
Linus Torvalds | a46ef99 | 2012-04-20 16:20:01 -0700 | [diff] [blame] | 2479 | |
| 2480 | down_write(&mm->mmap_sem); |
| 2481 | ret = do_munmap(mm, start, len); |
| 2482 | up_write(&mm->mmap_sem); |
| 2483 | return ret; |
| 2484 | } |
| 2485 | EXPORT_SYMBOL(vm_munmap); |
| 2486 | |
Heiko Carstens | 6a6160a | 2009-01-14 14:14:15 +0100 | [diff] [blame] | 2487 | SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2488 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2489 | profile_munmap(addr); |
Al Viro | bfce281 | 2012-04-20 21:57:04 -0400 | [diff] [blame] | 2490 | return vm_munmap(addr, len); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2491 | } |
| 2492 | |
| 2493 | static inline void verify_mm_writelocked(struct mm_struct *mm) |
| 2494 | { |
Paul E. McKenney | a241ec6 | 2005-10-30 15:03:12 -0800 | [diff] [blame] | 2495 | #ifdef CONFIG_DEBUG_VM |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2496 | if (unlikely(down_read_trylock(&mm->mmap_sem))) { |
| 2497 | WARN_ON(1); |
| 2498 | up_read(&mm->mmap_sem); |
| 2499 | } |
| 2500 | #endif |
| 2501 | } |
| 2502 | |
| 2503 | /* |
| 2504 | * this is really a simplified "do_mmap". it only handles |
| 2505 | * anonymous maps. eventually we may be able to do some |
| 2506 | * brk-specific accounting here. |
| 2507 | */ |
Linus Torvalds | e4eb1ff | 2012-04-20 15:35:40 -0700 | [diff] [blame] | 2508 | static unsigned long do_brk(unsigned long addr, unsigned long len) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2509 | { |
| 2510 | struct mm_struct * mm = current->mm; |
| 2511 | struct vm_area_struct * vma, * prev; |
| 2512 | unsigned long flags; |
| 2513 | struct rb_node ** rb_link, * rb_parent; |
| 2514 | pgoff_t pgoff = addr >> PAGE_SHIFT; |
Kirill Korotaev | 3a45975 | 2006-09-07 14:17:04 +0400 | [diff] [blame] | 2515 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2516 | |
| 2517 | len = PAGE_ALIGN(len); |
| 2518 | if (!len) |
| 2519 | return addr; |
| 2520 | |
Kirill Korotaev | 3a45975 | 2006-09-07 14:17:04 +0400 | [diff] [blame] | 2521 | flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; |
| 2522 | |
Al Viro | 2c6a101 | 2009-12-03 19:40:46 -0500 | [diff] [blame] | 2523 | error = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED); |
| 2524 | if (error & ~PAGE_MASK) |
Kirill Korotaev | 3a45975 | 2006-09-07 14:17:04 +0400 | [diff] [blame] | 2525 | return error; |
| 2526 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2527 | /* |
| 2528 | * mlock MCL_FUTURE? |
| 2529 | */ |
| 2530 | if (mm->def_flags & VM_LOCKED) { |
| 2531 | unsigned long locked, lock_limit; |
Chris Wright | 93ea1d0 | 2005-05-01 08:58:38 -0700 | [diff] [blame] | 2532 | locked = len >> PAGE_SHIFT; |
| 2533 | locked += mm->locked_vm; |
Jiri Slaby | 59e99e5 | 2010-03-05 13:41:44 -0800 | [diff] [blame] | 2534 | lock_limit = rlimit(RLIMIT_MEMLOCK); |
Chris Wright | 93ea1d0 | 2005-05-01 08:58:38 -0700 | [diff] [blame] | 2535 | lock_limit >>= PAGE_SHIFT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2536 | if (locked > lock_limit && !capable(CAP_IPC_LOCK)) |
| 2537 | return -EAGAIN; |
| 2538 | } |
| 2539 | |
| 2540 | /* |
| 2541 | * mm->mmap_sem is required to protect against another thread |
| 2542 | * changing the mappings in case we sleep. |
| 2543 | */ |
| 2544 | verify_mm_writelocked(mm); |
| 2545 | |
| 2546 | /* |
| 2547 | * Clear old maps. this also does some error checking for us |
| 2548 | */ |
| 2549 | munmap_back: |
Hugh Dickins | 6597d78 | 2012-10-08 16:29:07 -0700 | [diff] [blame] | 2550 | if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2551 | if (do_munmap(mm, addr, len)) |
| 2552 | return -ENOMEM; |
| 2553 | goto munmap_back; |
| 2554 | } |
| 2555 | |
| 2556 | /* Check against address space limits *after* clearing old maps... */ |
akpm@osdl.org | 119f657 | 2005-05-01 08:58:35 -0700 | [diff] [blame] | 2557 | if (!may_expand_vm(mm, len >> PAGE_SHIFT)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2558 | return -ENOMEM; |
| 2559 | |
| 2560 | if (mm->map_count > sysctl_max_map_count) |
| 2561 | return -ENOMEM; |
| 2562 | |
Al Viro | 191c542 | 2012-02-13 03:58:52 +0000 | [diff] [blame] | 2563 | if (security_vm_enough_memory_mm(mm, len >> PAGE_SHIFT)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2564 | return -ENOMEM; |
| 2565 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2566 | /* Can we just expand an old private anonymous mapping? */ |
Rik van Riel | ba470de | 2008-10-18 20:26:50 -0700 | [diff] [blame] | 2567 | vma = vma_merge(mm, prev, addr, addr + len, flags, |
| 2568 | NULL, NULL, pgoff, NULL); |
| 2569 | if (vma) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2570 | goto out; |
| 2571 | |
| 2572 | /* |
| 2573 | * create a vma struct for an anonymous mapping |
| 2574 | */ |
Pekka Enberg | c5e3b83 | 2006-03-25 03:06:43 -0800 | [diff] [blame] | 2575 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2576 | if (!vma) { |
| 2577 | vm_unacct_memory(len >> PAGE_SHIFT); |
| 2578 | return -ENOMEM; |
| 2579 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2580 | |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 2581 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2582 | vma->vm_mm = mm; |
| 2583 | vma->vm_start = addr; |
| 2584 | vma->vm_end = addr + len; |
| 2585 | vma->vm_pgoff = pgoff; |
| 2586 | vma->vm_flags = flags; |
Coly Li | 3ed75eb | 2007-10-18 23:39:15 -0700 | [diff] [blame] | 2587 | vma->vm_page_prot = vm_get_page_prot(flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2588 | vma_link(mm, vma, prev, rb_link, rb_parent); |
| 2589 | out: |
Eric B Munson | 3af9e85 | 2010-05-18 15:30:49 +0100 | [diff] [blame] | 2590 | perf_event_mmap(vma); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2591 | mm->total_vm += len >> PAGE_SHIFT; |
| 2592 | if (flags & VM_LOCKED) { |
Rik van Riel | ba470de | 2008-10-18 20:26:50 -0700 | [diff] [blame] | 2593 | if (!mlock_vma_pages_range(vma, addr, addr + len)) |
| 2594 | mm->locked_vm += (len >> PAGE_SHIFT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2595 | } |
| 2596 | return addr; |
| 2597 | } |
| 2598 | |
Linus Torvalds | e4eb1ff | 2012-04-20 15:35:40 -0700 | [diff] [blame] | 2599 | unsigned long vm_brk(unsigned long addr, unsigned long len) |
| 2600 | { |
| 2601 | struct mm_struct *mm = current->mm; |
| 2602 | unsigned long ret; |
| 2603 | |
| 2604 | down_write(&mm->mmap_sem); |
| 2605 | ret = do_brk(addr, len); |
| 2606 | up_write(&mm->mmap_sem); |
| 2607 | return ret; |
| 2608 | } |
| 2609 | EXPORT_SYMBOL(vm_brk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2610 | |
| 2611 | /* Release all mmaps. */ |
| 2612 | void exit_mmap(struct mm_struct *mm) |
| 2613 | { |
Peter Zijlstra | d16dfc5 | 2011-05-24 17:11:45 -0700 | [diff] [blame] | 2614 | struct mmu_gather tlb; |
Rik van Riel | ba470de | 2008-10-18 20:26:50 -0700 | [diff] [blame] | 2615 | struct vm_area_struct *vma; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2616 | unsigned long nr_accounted = 0; |
| 2617 | |
Jeremy Fitzhardinge | d6dd61c | 2007-05-02 19:27:14 +0200 | [diff] [blame] | 2618 | /* mm's last user has gone, and its about to be pulled down */ |
Andrea Arcangeli | cddb8a5 | 2008-07-28 15:46:29 -0700 | [diff] [blame] | 2619 | mmu_notifier_release(mm); |
Jeremy Fitzhardinge | d6dd61c | 2007-05-02 19:27:14 +0200 | [diff] [blame] | 2620 | |
Rik van Riel | ba470de | 2008-10-18 20:26:50 -0700 | [diff] [blame] | 2621 | if (mm->locked_vm) { |
| 2622 | vma = mm->mmap; |
| 2623 | while (vma) { |
| 2624 | if (vma->vm_flags & VM_LOCKED) |
| 2625 | munlock_vma_pages_all(vma); |
| 2626 | vma = vma->vm_next; |
| 2627 | } |
| 2628 | } |
Jeremy Fitzhardinge | 9480c53 | 2009-02-11 13:04:41 -0800 | [diff] [blame] | 2629 | |
| 2630 | arch_exit_mmap(mm); |
| 2631 | |
Rik van Riel | ba470de | 2008-10-18 20:26:50 -0700 | [diff] [blame] | 2632 | vma = mm->mmap; |
Jeremy Fitzhardinge | 9480c53 | 2009-02-11 13:04:41 -0800 | [diff] [blame] | 2633 | if (!vma) /* Can happen if dup_mmap() received an OOM */ |
| 2634 | return; |
| 2635 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2636 | lru_add_drain(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2637 | flush_cache_mm(mm); |
Peter Zijlstra | d16dfc5 | 2011-05-24 17:11:45 -0700 | [diff] [blame] | 2638 | tlb_gather_mmu(&tlb, mm, 1); |
Oleg Nesterov | 901608d | 2009-01-06 14:40:29 -0800 | [diff] [blame] | 2639 | /* update_hiwater_rss(mm) here? but nobody should be looking */ |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 2640 | /* Use -1 here to ensure all VMAs in the mm are unmapped */ |
Linus Torvalds | 4f74d2c | 2012-05-06 13:54:06 -0700 | [diff] [blame] | 2641 | unmap_vmas(&tlb, vma, 0, -1); |
Hugh Dickins | 9ba6929 | 2009-09-21 17:02:20 -0700 | [diff] [blame] | 2642 | |
Peter Zijlstra | d16dfc5 | 2011-05-24 17:11:45 -0700 | [diff] [blame] | 2643 | free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0); |
Al Viro | 853f5e2 | 2012-03-05 14:03:47 -0500 | [diff] [blame] | 2644 | tlb_finish_mmu(&tlb, 0, -1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2645 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2646 | /* |
Hugh Dickins | 8f4f8c1 | 2005-10-29 18:16:29 -0700 | [diff] [blame] | 2647 | * Walk the list again, actually closing and freeing it, |
| 2648 | * with preemption enabled, without holding any MM locks. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2649 | */ |
Linus Torvalds | 4f74d2c | 2012-05-06 13:54:06 -0700 | [diff] [blame] | 2650 | while (vma) { |
| 2651 | if (vma->vm_flags & VM_ACCOUNT) |
| 2652 | nr_accounted += vma_pages(vma); |
Hugh Dickins | a8fb561 | 2005-10-29 18:15:57 -0700 | [diff] [blame] | 2653 | vma = remove_vma(vma); |
Linus Torvalds | 4f74d2c | 2012-05-06 13:54:06 -0700 | [diff] [blame] | 2654 | } |
| 2655 | vm_unacct_memory(nr_accounted); |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 2656 | |
Hugh Dickins | f9aed62 | 2012-08-21 16:15:45 -0700 | [diff] [blame] | 2657 | WARN_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2658 | } |
| 2659 | |
| 2660 | /* Insert vm structure into process list sorted by address |
| 2661 | * and into the inode's i_mmap tree. If vm_file is non-NULL |
Peter Zijlstra | 3d48ae4 | 2011-05-24 17:12:06 -0700 | [diff] [blame] | 2662 | * then i_mmap_mutex is taken here. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2663 | */ |
Hugh Dickins | 6597d78 | 2012-10-08 16:29:07 -0700 | [diff] [blame] | 2664 | int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2665 | { |
Hugh Dickins | 6597d78 | 2012-10-08 16:29:07 -0700 | [diff] [blame] | 2666 | struct vm_area_struct *prev; |
| 2667 | struct rb_node **rb_link, *rb_parent; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2668 | |
| 2669 | /* |
| 2670 | * The vm_pgoff of a purely anonymous vma should be irrelevant |
| 2671 | * until its first write fault, when page's anon_vma and index |
| 2672 | * are set. But now set the vm_pgoff it will almost certainly |
| 2673 | * end up with (unless mremap moves it elsewhere before that |
| 2674 | * first wfault), so /proc/pid/maps tells a consistent story. |
| 2675 | * |
| 2676 | * By setting it to reflect the virtual start address of the |
| 2677 | * vma, merges and splits can happen in a seamless way, just |
| 2678 | * using the existing file pgoff checks and manipulations. |
| 2679 | * Similarly in do_mmap_pgoff and in do_brk. |
| 2680 | */ |
| 2681 | if (!vma->vm_file) { |
| 2682 | BUG_ON(vma->anon_vma); |
| 2683 | vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT; |
| 2684 | } |
Hugh Dickins | 6597d78 | 2012-10-08 16:29:07 -0700 | [diff] [blame] | 2685 | if (find_vma_links(mm, vma->vm_start, vma->vm_end, |
| 2686 | &prev, &rb_link, &rb_parent)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2687 | return -ENOMEM; |
Hugh Dickins | 2fd4ef8 | 2005-09-14 06:13:02 +0100 | [diff] [blame] | 2688 | if ((vma->vm_flags & VM_ACCOUNT) && |
Alan Cox | 34b4e4a | 2007-08-22 14:01:28 -0700 | [diff] [blame] | 2689 | security_vm_enough_memory_mm(mm, vma_pages(vma))) |
Hugh Dickins | 2fd4ef8 | 2005-09-14 06:13:02 +0100 | [diff] [blame] | 2690 | return -ENOMEM; |
Srikar Dronamraju | 2b14449 | 2012-02-09 14:56:42 +0530 | [diff] [blame] | 2691 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2692 | vma_link(mm, vma, prev, rb_link, rb_parent); |
| 2693 | return 0; |
| 2694 | } |
| 2695 | |
| 2696 | /* |
| 2697 | * Copy the vma structure to a new location in the same mm, |
| 2698 | * prior to moving page table entries, to effect an mremap move. |
| 2699 | */ |
| 2700 | struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, |
Michel Lespinasse | 38a7601 | 2012-10-08 16:31:50 -0700 | [diff] [blame] | 2701 | unsigned long addr, unsigned long len, pgoff_t pgoff, |
| 2702 | bool *need_rmap_locks) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2703 | { |
| 2704 | struct vm_area_struct *vma = *vmap; |
| 2705 | unsigned long vma_start = vma->vm_start; |
| 2706 | struct mm_struct *mm = vma->vm_mm; |
| 2707 | struct vm_area_struct *new_vma, *prev; |
| 2708 | struct rb_node **rb_link, *rb_parent; |
| 2709 | struct mempolicy *pol; |
Andrea Arcangeli | 948f017 | 2012-01-10 15:08:05 -0800 | [diff] [blame] | 2710 | bool faulted_in_anon_vma = true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2711 | |
| 2712 | /* |
| 2713 | * If anonymous vma has not yet been faulted, update new pgoff |
| 2714 | * to match new location, to increase its chance of merging. |
| 2715 | */ |
Andrea Arcangeli | 948f017 | 2012-01-10 15:08:05 -0800 | [diff] [blame] | 2716 | if (unlikely(!vma->vm_file && !vma->anon_vma)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2717 | pgoff = addr >> PAGE_SHIFT; |
Andrea Arcangeli | 948f017 | 2012-01-10 15:08:05 -0800 | [diff] [blame] | 2718 | faulted_in_anon_vma = false; |
| 2719 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2720 | |
Hugh Dickins | 6597d78 | 2012-10-08 16:29:07 -0700 | [diff] [blame] | 2721 | if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) |
| 2722 | return NULL; /* should never get here */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2723 | new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags, |
| 2724 | vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma)); |
| 2725 | if (new_vma) { |
| 2726 | /* |
| 2727 | * Source vma may have been merged into new_vma |
| 2728 | */ |
Andrea Arcangeli | 948f017 | 2012-01-10 15:08:05 -0800 | [diff] [blame] | 2729 | if (unlikely(vma_start >= new_vma->vm_start && |
| 2730 | vma_start < new_vma->vm_end)) { |
| 2731 | /* |
| 2732 | * The only way we can get a vma_merge with |
| 2733 | * self during an mremap is if the vma hasn't |
| 2734 | * been faulted in yet and we were allowed to |
| 2735 | * reset the dst vma->vm_pgoff to the |
| 2736 | * destination address of the mremap to allow |
| 2737 | * the merge to happen. mremap must change the |
| 2738 | * vm_pgoff linearity between src and dst vmas |
| 2739 | * (in turn preventing a vma_merge) to be |
| 2740 | * safe. It is only safe to keep the vm_pgoff |
| 2741 | * linear if there are no pages mapped yet. |
| 2742 | */ |
| 2743 | VM_BUG_ON(faulted_in_anon_vma); |
Michel Lespinasse | 38a7601 | 2012-10-08 16:31:50 -0700 | [diff] [blame] | 2744 | *vmap = vma = new_vma; |
Michel Lespinasse | 108d664 | 2012-10-08 16:31:36 -0700 | [diff] [blame] | 2745 | } |
Michel Lespinasse | 38a7601 | 2012-10-08 16:31:50 -0700 | [diff] [blame] | 2746 | *need_rmap_locks = (new_vma->vm_pgoff <= vma->vm_pgoff); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2747 | } else { |
Christoph Lameter | e94b176 | 2006-12-06 20:33:17 -0800 | [diff] [blame] | 2748 | new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2749 | if (new_vma) { |
| 2750 | *new_vma = *vma; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2751 | new_vma->vm_start = addr; |
| 2752 | new_vma->vm_end = addr + len; |
| 2753 | new_vma->vm_pgoff = pgoff; |
Michel Lespinasse | 523d4e2 | 2012-10-08 16:31:48 -0700 | [diff] [blame] | 2754 | pol = mpol_dup(vma_policy(vma)); |
| 2755 | if (IS_ERR(pol)) |
| 2756 | goto out_free_vma; |
| 2757 | vma_set_policy(new_vma, pol); |
| 2758 | INIT_LIST_HEAD(&new_vma->anon_vma_chain); |
| 2759 | if (anon_vma_clone(new_vma, vma)) |
| 2760 | goto out_free_mempol; |
Konstantin Khlebnikov | e9714ac | 2012-10-08 16:28:54 -0700 | [diff] [blame] | 2761 | if (new_vma->vm_file) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2762 | get_file(new_vma->vm_file); |
| 2763 | if (new_vma->vm_ops && new_vma->vm_ops->open) |
| 2764 | new_vma->vm_ops->open(new_vma); |
| 2765 | vma_link(mm, new_vma, prev, rb_link, rb_parent); |
Michel Lespinasse | 38a7601 | 2012-10-08 16:31:50 -0700 | [diff] [blame] | 2766 | *need_rmap_locks = false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2767 | } |
| 2768 | } |
| 2769 | return new_vma; |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 2770 | |
| 2771 | out_free_mempol: |
| 2772 | mpol_put(pol); |
| 2773 | out_free_vma: |
| 2774 | kmem_cache_free(vm_area_cachep, new_vma); |
| 2775 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2776 | } |
akpm@osdl.org | 119f657 | 2005-05-01 08:58:35 -0700 | [diff] [blame] | 2777 | |
| 2778 | /* |
| 2779 | * Return true if the calling process may expand its vm space by the passed |
| 2780 | * number of pages |
| 2781 | */ |
| 2782 | int may_expand_vm(struct mm_struct *mm, unsigned long npages) |
| 2783 | { |
| 2784 | unsigned long cur = mm->total_vm; /* pages */ |
| 2785 | unsigned long lim; |
| 2786 | |
Jiri Slaby | 59e99e5 | 2010-03-05 13:41:44 -0800 | [diff] [blame] | 2787 | lim = rlimit(RLIMIT_AS) >> PAGE_SHIFT; |
akpm@osdl.org | 119f657 | 2005-05-01 08:58:35 -0700 | [diff] [blame] | 2788 | |
| 2789 | if (cur + npages > lim) |
| 2790 | return 0; |
| 2791 | return 1; |
| 2792 | } |
Roland McGrath | fa5dc22 | 2007-02-08 14:20:41 -0800 | [diff] [blame] | 2793 | |
| 2794 | |
Nick Piggin | b1d0e4f | 2008-02-09 01:15:19 +0100 | [diff] [blame] | 2795 | static int special_mapping_fault(struct vm_area_struct *vma, |
| 2796 | struct vm_fault *vmf) |
Roland McGrath | fa5dc22 | 2007-02-08 14:20:41 -0800 | [diff] [blame] | 2797 | { |
Nick Piggin | b1d0e4f | 2008-02-09 01:15:19 +0100 | [diff] [blame] | 2798 | pgoff_t pgoff; |
Roland McGrath | fa5dc22 | 2007-02-08 14:20:41 -0800 | [diff] [blame] | 2799 | struct page **pages; |
| 2800 | |
Nick Piggin | b1d0e4f | 2008-02-09 01:15:19 +0100 | [diff] [blame] | 2801 | /* |
| 2802 | * special mappings have no vm_file, and in that case, the mm |
| 2803 | * uses vm_pgoff internally. So we have to subtract it from here. |
| 2804 | * We are allowed to do this because we are the mm; do not copy |
| 2805 | * this code into drivers! |
| 2806 | */ |
| 2807 | pgoff = vmf->pgoff - vma->vm_pgoff; |
Roland McGrath | fa5dc22 | 2007-02-08 14:20:41 -0800 | [diff] [blame] | 2808 | |
Nick Piggin | b1d0e4f | 2008-02-09 01:15:19 +0100 | [diff] [blame] | 2809 | for (pages = vma->vm_private_data; pgoff && *pages; ++pages) |
| 2810 | pgoff--; |
Roland McGrath | fa5dc22 | 2007-02-08 14:20:41 -0800 | [diff] [blame] | 2811 | |
| 2812 | if (*pages) { |
| 2813 | struct page *page = *pages; |
| 2814 | get_page(page); |
Nick Piggin | b1d0e4f | 2008-02-09 01:15:19 +0100 | [diff] [blame] | 2815 | vmf->page = page; |
| 2816 | return 0; |
Roland McGrath | fa5dc22 | 2007-02-08 14:20:41 -0800 | [diff] [blame] | 2817 | } |
| 2818 | |
Nick Piggin | b1d0e4f | 2008-02-09 01:15:19 +0100 | [diff] [blame] | 2819 | return VM_FAULT_SIGBUS; |
Roland McGrath | fa5dc22 | 2007-02-08 14:20:41 -0800 | [diff] [blame] | 2820 | } |
| 2821 | |
| 2822 | /* |
| 2823 | * Having a close hook prevents vma merging regardless of flags. |
| 2824 | */ |
| 2825 | static void special_mapping_close(struct vm_area_struct *vma) |
| 2826 | { |
| 2827 | } |
| 2828 | |
Alexey Dobriyan | f0f37e2f | 2009-09-27 22:29:37 +0400 | [diff] [blame] | 2829 | static const struct vm_operations_struct special_mapping_vmops = { |
Roland McGrath | fa5dc22 | 2007-02-08 14:20:41 -0800 | [diff] [blame] | 2830 | .close = special_mapping_close, |
Nick Piggin | b1d0e4f | 2008-02-09 01:15:19 +0100 | [diff] [blame] | 2831 | .fault = special_mapping_fault, |
Roland McGrath | fa5dc22 | 2007-02-08 14:20:41 -0800 | [diff] [blame] | 2832 | }; |
| 2833 | |
| 2834 | /* |
| 2835 | * Called with mm->mmap_sem held for writing. |
| 2836 | * Insert a new vma covering the given region, with the given flags. |
| 2837 | * Its pages are supplied by the given array of struct page *. |
| 2838 | * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated. |
| 2839 | * The region past the last page supplied will always produce SIGBUS. |
| 2840 | * The array pointer and the pages it points to are assumed to stay alive |
| 2841 | * for as long as this mapping might exist. |
| 2842 | */ |
| 2843 | int install_special_mapping(struct mm_struct *mm, |
| 2844 | unsigned long addr, unsigned long len, |
| 2845 | unsigned long vm_flags, struct page **pages) |
| 2846 | { |
Tavis Ormandy | 462e635e | 2010-12-09 15:29:42 +0100 | [diff] [blame] | 2847 | int ret; |
Roland McGrath | fa5dc22 | 2007-02-08 14:20:41 -0800 | [diff] [blame] | 2848 | struct vm_area_struct *vma; |
| 2849 | |
| 2850 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
| 2851 | if (unlikely(vma == NULL)) |
| 2852 | return -ENOMEM; |
| 2853 | |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 2854 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
Roland McGrath | fa5dc22 | 2007-02-08 14:20:41 -0800 | [diff] [blame] | 2855 | vma->vm_mm = mm; |
| 2856 | vma->vm_start = addr; |
| 2857 | vma->vm_end = addr + len; |
| 2858 | |
Nick Piggin | 2f98735 | 2008-02-02 03:08:53 +0100 | [diff] [blame] | 2859 | vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND; |
Coly Li | 3ed75eb | 2007-10-18 23:39:15 -0700 | [diff] [blame] | 2860 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); |
Roland McGrath | fa5dc22 | 2007-02-08 14:20:41 -0800 | [diff] [blame] | 2861 | |
| 2862 | vma->vm_ops = &special_mapping_vmops; |
| 2863 | vma->vm_private_data = pages; |
| 2864 | |
Tavis Ormandy | 462e635e | 2010-12-09 15:29:42 +0100 | [diff] [blame] | 2865 | ret = insert_vm_struct(mm, vma); |
| 2866 | if (ret) |
| 2867 | goto out; |
Roland McGrath | fa5dc22 | 2007-02-08 14:20:41 -0800 | [diff] [blame] | 2868 | |
| 2869 | mm->total_vm += len >> PAGE_SHIFT; |
| 2870 | |
Ingo Molnar | cdd6c48 | 2009-09-21 12:02:48 +0200 | [diff] [blame] | 2871 | perf_event_mmap(vma); |
Peter Zijlstra | 089dd79 | 2009-06-05 14:04:55 +0200 | [diff] [blame] | 2872 | |
Roland McGrath | fa5dc22 | 2007-02-08 14:20:41 -0800 | [diff] [blame] | 2873 | return 0; |
Tavis Ormandy | 462e635e | 2010-12-09 15:29:42 +0100 | [diff] [blame] | 2874 | |
| 2875 | out: |
| 2876 | kmem_cache_free(vm_area_cachep, vma); |
| 2877 | return ret; |
Roland McGrath | fa5dc22 | 2007-02-08 14:20:41 -0800 | [diff] [blame] | 2878 | } |
Andrea Arcangeli | 7906d00 | 2008-07-28 15:46:26 -0700 | [diff] [blame] | 2879 | |
| 2880 | static DEFINE_MUTEX(mm_all_locks_mutex); |
| 2881 | |
Peter Zijlstra | 454ed84 | 2008-08-11 09:30:25 +0200 | [diff] [blame] | 2882 | static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma) |
Andrea Arcangeli | 7906d00 | 2008-07-28 15:46:26 -0700 | [diff] [blame] | 2883 | { |
Michel Lespinasse | bf181b9 | 2012-10-08 16:31:39 -0700 | [diff] [blame] | 2884 | if (!test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_node)) { |
Andrea Arcangeli | 7906d00 | 2008-07-28 15:46:26 -0700 | [diff] [blame] | 2885 | /* |
| 2886 | * The LSB of head.next can't change from under us |
| 2887 | * because we hold the mm_all_locks_mutex. |
| 2888 | */ |
Jiri Kosina | 572043c | 2013-01-11 14:31:59 -0800 | [diff] [blame] | 2889 | down_write_nest_lock(&anon_vma->root->rwsem, &mm->mmap_sem); |
Andrea Arcangeli | 7906d00 | 2008-07-28 15:46:26 -0700 | [diff] [blame] | 2890 | /* |
| 2891 | * We can safely modify head.next after taking the |
Ingo Molnar | 5a50508 | 2012-12-02 19:56:46 +0000 | [diff] [blame] | 2892 | * anon_vma->root->rwsem. If some other vma in this mm shares |
Andrea Arcangeli | 7906d00 | 2008-07-28 15:46:26 -0700 | [diff] [blame] | 2893 | * the same anon_vma we won't take it again. |
| 2894 | * |
| 2895 | * No need of atomic instructions here, head.next |
| 2896 | * can't change from under us thanks to the |
Ingo Molnar | 5a50508 | 2012-12-02 19:56:46 +0000 | [diff] [blame] | 2897 | * anon_vma->root->rwsem. |
Andrea Arcangeli | 7906d00 | 2008-07-28 15:46:26 -0700 | [diff] [blame] | 2898 | */ |
| 2899 | if (__test_and_set_bit(0, (unsigned long *) |
Michel Lespinasse | bf181b9 | 2012-10-08 16:31:39 -0700 | [diff] [blame] | 2900 | &anon_vma->root->rb_root.rb_node)) |
Andrea Arcangeli | 7906d00 | 2008-07-28 15:46:26 -0700 | [diff] [blame] | 2901 | BUG(); |
| 2902 | } |
| 2903 | } |
| 2904 | |
Peter Zijlstra | 454ed84 | 2008-08-11 09:30:25 +0200 | [diff] [blame] | 2905 | static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping) |
Andrea Arcangeli | 7906d00 | 2008-07-28 15:46:26 -0700 | [diff] [blame] | 2906 | { |
| 2907 | if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { |
| 2908 | /* |
| 2909 | * AS_MM_ALL_LOCKS can't change from under us because |
| 2910 | * we hold the mm_all_locks_mutex. |
| 2911 | * |
| 2912 | * Operations on ->flags have to be atomic because |
| 2913 | * even if AS_MM_ALL_LOCKS is stable thanks to the |
| 2914 | * mm_all_locks_mutex, there may be other cpus |
| 2915 | * changing other bitflags in parallel to us. |
| 2916 | */ |
| 2917 | if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags)) |
| 2918 | BUG(); |
Peter Zijlstra | 3d48ae4 | 2011-05-24 17:12:06 -0700 | [diff] [blame] | 2919 | mutex_lock_nest_lock(&mapping->i_mmap_mutex, &mm->mmap_sem); |
Andrea Arcangeli | 7906d00 | 2008-07-28 15:46:26 -0700 | [diff] [blame] | 2920 | } |
| 2921 | } |
| 2922 | |
| 2923 | /* |
| 2924 | * This operation locks against the VM for all pte/vma/mm related |
| 2925 | * operations that could ever happen on a certain mm. This includes |
| 2926 | * vmtruncate, try_to_unmap, and all page faults. |
| 2927 | * |
| 2928 | * The caller must take the mmap_sem in write mode before calling |
| 2929 | * mm_take_all_locks(). The caller isn't allowed to release the |
| 2930 | * mmap_sem until mm_drop_all_locks() returns. |
| 2931 | * |
| 2932 | * mmap_sem in write mode is required in order to block all operations |
| 2933 | * that could modify pagetables and free pages without need of |
| 2934 | * altering the vma layout (for example populate_range() with |
| 2935 | * nonlinear vmas). It's also needed in write mode to avoid new |
| 2936 | * anon_vmas to be associated with existing vmas. |
| 2937 | * |
| 2938 | * A single task can't take more than one mm_take_all_locks() in a row |
| 2939 | * or it would deadlock. |
| 2940 | * |
Michel Lespinasse | bf181b9 | 2012-10-08 16:31:39 -0700 | [diff] [blame] | 2941 | * The LSB in anon_vma->rb_root.rb_node and the AS_MM_ALL_LOCKS bitflag in |
Andrea Arcangeli | 7906d00 | 2008-07-28 15:46:26 -0700 | [diff] [blame] | 2942 | * mapping->flags avoid to take the same lock twice, if more than one |
| 2943 | * vma in this mm is backed by the same anon_vma or address_space. |
| 2944 | * |
| 2945 | * We can take all the locks in random order because the VM code |
Peter Zijlstra | 2b575eb | 2011-05-24 17:12:11 -0700 | [diff] [blame] | 2946 | * taking i_mmap_mutex or anon_vma->mutex outside the mmap_sem never |
Andrea Arcangeli | 7906d00 | 2008-07-28 15:46:26 -0700 | [diff] [blame] | 2947 | * takes more than one of them in a row. Secondly we're protected |
| 2948 | * against a concurrent mm_take_all_locks() by the mm_all_locks_mutex. |
| 2949 | * |
| 2950 | * mm_take_all_locks() and mm_drop_all_locks are expensive operations |
| 2951 | * that may have to take thousand of locks. |
| 2952 | * |
| 2953 | * mm_take_all_locks() can fail if it's interrupted by signals. |
| 2954 | */ |
| 2955 | int mm_take_all_locks(struct mm_struct *mm) |
| 2956 | { |
| 2957 | struct vm_area_struct *vma; |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 2958 | struct anon_vma_chain *avc; |
Andrea Arcangeli | 7906d00 | 2008-07-28 15:46:26 -0700 | [diff] [blame] | 2959 | |
| 2960 | BUG_ON(down_read_trylock(&mm->mmap_sem)); |
| 2961 | |
| 2962 | mutex_lock(&mm_all_locks_mutex); |
| 2963 | |
| 2964 | for (vma = mm->mmap; vma; vma = vma->vm_next) { |
| 2965 | if (signal_pending(current)) |
| 2966 | goto out_unlock; |
Andrea Arcangeli | 7906d00 | 2008-07-28 15:46:26 -0700 | [diff] [blame] | 2967 | if (vma->vm_file && vma->vm_file->f_mapping) |
Peter Zijlstra | 454ed84 | 2008-08-11 09:30:25 +0200 | [diff] [blame] | 2968 | vm_lock_mapping(mm, vma->vm_file->f_mapping); |
Andrea Arcangeli | 7906d00 | 2008-07-28 15:46:26 -0700 | [diff] [blame] | 2969 | } |
Peter Zijlstra | 7cd5a02 | 2008-08-11 09:30:25 +0200 | [diff] [blame] | 2970 | |
| 2971 | for (vma = mm->mmap; vma; vma = vma->vm_next) { |
| 2972 | if (signal_pending(current)) |
| 2973 | goto out_unlock; |
| 2974 | if (vma->anon_vma) |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 2975 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) |
| 2976 | vm_lock_anon_vma(mm, avc->anon_vma); |
Peter Zijlstra | 7cd5a02 | 2008-08-11 09:30:25 +0200 | [diff] [blame] | 2977 | } |
| 2978 | |
Kautuk Consul | 584cff5 | 2011-10-31 17:08:59 -0700 | [diff] [blame] | 2979 | return 0; |
Andrea Arcangeli | 7906d00 | 2008-07-28 15:46:26 -0700 | [diff] [blame] | 2980 | |
| 2981 | out_unlock: |
Kautuk Consul | 584cff5 | 2011-10-31 17:08:59 -0700 | [diff] [blame] | 2982 | mm_drop_all_locks(mm); |
| 2983 | return -EINTR; |
Andrea Arcangeli | 7906d00 | 2008-07-28 15:46:26 -0700 | [diff] [blame] | 2984 | } |
| 2985 | |
| 2986 | static void vm_unlock_anon_vma(struct anon_vma *anon_vma) |
| 2987 | { |
Michel Lespinasse | bf181b9 | 2012-10-08 16:31:39 -0700 | [diff] [blame] | 2988 | if (test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_node)) { |
Andrea Arcangeli | 7906d00 | 2008-07-28 15:46:26 -0700 | [diff] [blame] | 2989 | /* |
| 2990 | * The LSB of head.next can't change to 0 from under |
| 2991 | * us because we hold the mm_all_locks_mutex. |
| 2992 | * |
| 2993 | * We must however clear the bitflag before unlocking |
Michel Lespinasse | bf181b9 | 2012-10-08 16:31:39 -0700 | [diff] [blame] | 2994 | * the vma so the users using the anon_vma->rb_root will |
Andrea Arcangeli | 7906d00 | 2008-07-28 15:46:26 -0700 | [diff] [blame] | 2995 | * never see our bitflag. |
| 2996 | * |
| 2997 | * No need of atomic instructions here, head.next |
| 2998 | * can't change from under us until we release the |
Ingo Molnar | 5a50508 | 2012-12-02 19:56:46 +0000 | [diff] [blame] | 2999 | * anon_vma->root->rwsem. |
Andrea Arcangeli | 7906d00 | 2008-07-28 15:46:26 -0700 | [diff] [blame] | 3000 | */ |
| 3001 | if (!__test_and_clear_bit(0, (unsigned long *) |
Michel Lespinasse | bf181b9 | 2012-10-08 16:31:39 -0700 | [diff] [blame] | 3002 | &anon_vma->root->rb_root.rb_node)) |
Andrea Arcangeli | 7906d00 | 2008-07-28 15:46:26 -0700 | [diff] [blame] | 3003 | BUG(); |
Rik van Riel | cba48b9 | 2010-08-09 17:18:38 -0700 | [diff] [blame] | 3004 | anon_vma_unlock(anon_vma); |
Andrea Arcangeli | 7906d00 | 2008-07-28 15:46:26 -0700 | [diff] [blame] | 3005 | } |
| 3006 | } |
| 3007 | |
| 3008 | static void vm_unlock_mapping(struct address_space *mapping) |
| 3009 | { |
| 3010 | if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { |
| 3011 | /* |
| 3012 | * AS_MM_ALL_LOCKS can't change to 0 from under us |
| 3013 | * because we hold the mm_all_locks_mutex. |
| 3014 | */ |
Peter Zijlstra | 3d48ae4 | 2011-05-24 17:12:06 -0700 | [diff] [blame] | 3015 | mutex_unlock(&mapping->i_mmap_mutex); |
Andrea Arcangeli | 7906d00 | 2008-07-28 15:46:26 -0700 | [diff] [blame] | 3016 | if (!test_and_clear_bit(AS_MM_ALL_LOCKS, |
| 3017 | &mapping->flags)) |
| 3018 | BUG(); |
| 3019 | } |
| 3020 | } |
| 3021 | |
| 3022 | /* |
| 3023 | * The mmap_sem cannot be released by the caller until |
| 3024 | * mm_drop_all_locks() returns. |
| 3025 | */ |
| 3026 | void mm_drop_all_locks(struct mm_struct *mm) |
| 3027 | { |
| 3028 | struct vm_area_struct *vma; |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 3029 | struct anon_vma_chain *avc; |
Andrea Arcangeli | 7906d00 | 2008-07-28 15:46:26 -0700 | [diff] [blame] | 3030 | |
| 3031 | BUG_ON(down_read_trylock(&mm->mmap_sem)); |
| 3032 | BUG_ON(!mutex_is_locked(&mm_all_locks_mutex)); |
| 3033 | |
| 3034 | for (vma = mm->mmap; vma; vma = vma->vm_next) { |
| 3035 | if (vma->anon_vma) |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 3036 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) |
| 3037 | vm_unlock_anon_vma(avc->anon_vma); |
Andrea Arcangeli | 7906d00 | 2008-07-28 15:46:26 -0700 | [diff] [blame] | 3038 | if (vma->vm_file && vma->vm_file->f_mapping) |
| 3039 | vm_unlock_mapping(vma->vm_file->f_mapping); |
| 3040 | } |
| 3041 | |
| 3042 | mutex_unlock(&mm_all_locks_mutex); |
| 3043 | } |
David Howells | 8feae13 | 2009-01-08 12:04:47 +0000 | [diff] [blame] | 3044 | |
| 3045 | /* |
| 3046 | * initialise the VMA slab |
| 3047 | */ |
| 3048 | void __init mmap_init(void) |
| 3049 | { |
KOSAKI Motohiro | 00a62ce | 2009-04-30 15:08:51 -0700 | [diff] [blame] | 3050 | int ret; |
| 3051 | |
| 3052 | ret = percpu_counter_init(&vm_committed_as, 0); |
| 3053 | VM_BUG_ON(ret); |
David Howells | 8feae13 | 2009-01-08 12:04:47 +0000 | [diff] [blame] | 3054 | } |