| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * linux/mm/mlock.c |
| * |
| * (C) Copyright 1995 Linus Torvalds |
| * (C) Copyright 2002 Christoph Hellwig |
| */ |
| |
| #include <linux/capability.h> |
| #include <linux/mman.h> |
| #include <linux/mm.h> |
| #include <linux/sched/user.h> |
| #include <linux/swap.h> |
| #include <linux/swapops.h> |
| #include <linux/pagemap.h> |
| #include <linux/pagevec.h> |
| #include <linux/pagewalk.h> |
| #include <linux/mempolicy.h> |
| #include <linux/syscalls.h> |
| #include <linux/sched.h> |
| #include <linux/export.h> |
| #include <linux/rmap.h> |
| #include <linux/mmzone.h> |
| #include <linux/hugetlb.h> |
| #include <linux/memcontrol.h> |
| #include <linux/mm_inline.h> |
| #include <linux/secretmem.h> |
| |
| #include "internal.h" |
| |
| struct mlock_fbatch { |
| local_lock_t lock; |
| struct folio_batch fbatch; |
| }; |
| |
| static DEFINE_PER_CPU(struct mlock_fbatch, mlock_fbatch) = { |
| .lock = INIT_LOCAL_LOCK(lock), |
| }; |
| |
| bool can_do_mlock(void) |
| { |
| if (rlimit(RLIMIT_MEMLOCK) != 0) |
| return true; |
| if (capable(CAP_IPC_LOCK)) |
| return true; |
| return false; |
| } |
| EXPORT_SYMBOL(can_do_mlock); |
| |
| /* |
| * Mlocked folios are marked with the PG_mlocked flag for efficient testing |
| * in vmscan and, possibly, the fault path; and to support semi-accurate |
| * statistics. |
| * |
| * An mlocked folio [folio_test_mlocked(folio)] is unevictable. As such, it |
| * will be ostensibly placed on the LRU "unevictable" list (actually no such |
| * list exists), rather than the [in]active lists. PG_unevictable is set to |
| * indicate the unevictable state. |
| */ |
| |
| static struct lruvec *__mlock_folio(struct folio *folio, struct lruvec *lruvec) |
| { |
| /* There is nothing more we can do while it's off LRU */ |
| if (!folio_test_clear_lru(folio)) |
| return lruvec; |
| |
| lruvec = folio_lruvec_relock_irq(folio, lruvec); |
| |
| if (unlikely(folio_evictable(folio))) { |
| /* |
| * This is a little surprising, but quite possible: PG_mlocked |
| * must have got cleared already by another CPU. Could this |
| * folio be unevictable? I'm not sure, but move it now if so. |
| */ |
| if (folio_test_unevictable(folio)) { |
| lruvec_del_folio(lruvec, folio); |
| folio_clear_unevictable(folio); |
| lruvec_add_folio(lruvec, folio); |
| |
| __count_vm_events(UNEVICTABLE_PGRESCUED, |
| folio_nr_pages(folio)); |
| } |
| goto out; |
| } |
| |
| if (folio_test_unevictable(folio)) { |
| if (folio_test_mlocked(folio)) |
| folio->mlock_count++; |
| goto out; |
| } |
| |
| lruvec_del_folio(lruvec, folio); |
| folio_clear_active(folio); |
| folio_set_unevictable(folio); |
| folio->mlock_count = !!folio_test_mlocked(folio); |
| lruvec_add_folio(lruvec, folio); |
| __count_vm_events(UNEVICTABLE_PGCULLED, folio_nr_pages(folio)); |
| out: |
| folio_set_lru(folio); |
| return lruvec; |
| } |
| |
| static struct lruvec *__mlock_new_folio(struct folio *folio, struct lruvec *lruvec) |
| { |
| VM_BUG_ON_FOLIO(folio_test_lru(folio), folio); |
| |
| lruvec = folio_lruvec_relock_irq(folio, lruvec); |
| |
| /* As above, this is a little surprising, but possible */ |
| if (unlikely(folio_evictable(folio))) |
| goto out; |
| |
| folio_set_unevictable(folio); |
| folio->mlock_count = !!folio_test_mlocked(folio); |
| __count_vm_events(UNEVICTABLE_PGCULLED, folio_nr_pages(folio)); |
| out: |
| lruvec_add_folio(lruvec, folio); |
| folio_set_lru(folio); |
| return lruvec; |
| } |
| |
| static struct lruvec *__munlock_folio(struct folio *folio, struct lruvec *lruvec) |
| { |
| int nr_pages = folio_nr_pages(folio); |
| bool isolated = false; |
| |
| if (!folio_test_clear_lru(folio)) |
| goto munlock; |
| |
| isolated = true; |
| lruvec = folio_lruvec_relock_irq(folio, lruvec); |
| |
| if (folio_test_unevictable(folio)) { |
| /* Then mlock_count is maintained, but might undercount */ |
| if (folio->mlock_count) |
| folio->mlock_count--; |
| if (folio->mlock_count) |
| goto out; |
| } |
| /* else assume that was the last mlock: reclaim will fix it if not */ |
| |
| munlock: |
| if (folio_test_clear_mlocked(folio)) { |
| __zone_stat_mod_folio(folio, NR_MLOCK, -nr_pages); |
| if (isolated || !folio_test_unevictable(folio)) |
| __count_vm_events(UNEVICTABLE_PGMUNLOCKED, nr_pages); |
| else |
| __count_vm_events(UNEVICTABLE_PGSTRANDED, nr_pages); |
| } |
| |
| /* folio_evictable() has to be checked *after* clearing Mlocked */ |
| if (isolated && folio_test_unevictable(folio) && folio_evictable(folio)) { |
| lruvec_del_folio(lruvec, folio); |
| folio_clear_unevictable(folio); |
| lruvec_add_folio(lruvec, folio); |
| __count_vm_events(UNEVICTABLE_PGRESCUED, nr_pages); |
| } |
| out: |
| if (isolated) |
| folio_set_lru(folio); |
| return lruvec; |
| } |
| |
| /* |
| * Flags held in the low bits of a struct folio pointer on the mlock_fbatch. |
| */ |
| #define LRU_FOLIO 0x1 |
| #define NEW_FOLIO 0x2 |
| static inline struct folio *mlock_lru(struct folio *folio) |
| { |
| return (struct folio *)((unsigned long)folio + LRU_FOLIO); |
| } |
| |
| static inline struct folio *mlock_new(struct folio *folio) |
| { |
| return (struct folio *)((unsigned long)folio + NEW_FOLIO); |
| } |
| |
| /* |
| * mlock_folio_batch() is derived from folio_batch_move_lru(): perhaps that can |
| * make use of such folio pointer flags in future, but for now just keep it for |
| * mlock. We could use three separate folio batches instead, but one feels |
| * better (munlocking a full folio batch does not need to drain mlocking folio |
| * batches first). |
| */ |
| static void mlock_folio_batch(struct folio_batch *fbatch) |
| { |
| struct lruvec *lruvec = NULL; |
| unsigned long mlock; |
| struct folio *folio; |
| int i; |
| |
| for (i = 0; i < folio_batch_count(fbatch); i++) { |
| folio = fbatch->folios[i]; |
| mlock = (unsigned long)folio & (LRU_FOLIO | NEW_FOLIO); |
| folio = (struct folio *)((unsigned long)folio - mlock); |
| fbatch->folios[i] = folio; |
| |
| if (mlock & LRU_FOLIO) |
| lruvec = __mlock_folio(folio, lruvec); |
| else if (mlock & NEW_FOLIO) |
| lruvec = __mlock_new_folio(folio, lruvec); |
| else |
| lruvec = __munlock_folio(folio, lruvec); |
| } |
| |
| if (lruvec) |
| unlock_page_lruvec_irq(lruvec); |
| release_pages(fbatch->folios, fbatch->nr); |
| folio_batch_reinit(fbatch); |
| } |
| |
| void mlock_drain_local(void) |
| { |
| struct folio_batch *fbatch; |
| |
| local_lock(&mlock_fbatch.lock); |
| fbatch = this_cpu_ptr(&mlock_fbatch.fbatch); |
| if (folio_batch_count(fbatch)) |
| mlock_folio_batch(fbatch); |
| local_unlock(&mlock_fbatch.lock); |
| } |
| |
| void mlock_drain_remote(int cpu) |
| { |
| struct folio_batch *fbatch; |
| |
| WARN_ON_ONCE(cpu_online(cpu)); |
| fbatch = &per_cpu(mlock_fbatch.fbatch, cpu); |
| if (folio_batch_count(fbatch)) |
| mlock_folio_batch(fbatch); |
| } |
| |
| bool need_mlock_drain(int cpu) |
| { |
| return folio_batch_count(&per_cpu(mlock_fbatch.fbatch, cpu)); |
| } |
| |
| /** |
| * mlock_folio - mlock a folio already on (or temporarily off) LRU |
| * @folio: folio to be mlocked. |
| */ |
| void mlock_folio(struct folio *folio) |
| { |
| struct folio_batch *fbatch; |
| |
| local_lock(&mlock_fbatch.lock); |
| fbatch = this_cpu_ptr(&mlock_fbatch.fbatch); |
| |
| if (!folio_test_set_mlocked(folio)) { |
| int nr_pages = folio_nr_pages(folio); |
| |
| zone_stat_mod_folio(folio, NR_MLOCK, nr_pages); |
| __count_vm_events(UNEVICTABLE_PGMLOCKED, nr_pages); |
| } |
| |
| folio_get(folio); |
| if (!folio_batch_add(fbatch, mlock_lru(folio)) || |
| folio_test_large(folio) || lru_cache_disabled()) |
| mlock_folio_batch(fbatch); |
| local_unlock(&mlock_fbatch.lock); |
| } |
| |
| /** |
| * mlock_new_folio - mlock a newly allocated folio not yet on LRU |
| * @folio: folio to be mlocked, either normal or a THP head. |
| */ |
| void mlock_new_folio(struct folio *folio) |
| { |
| struct folio_batch *fbatch; |
| int nr_pages = folio_nr_pages(folio); |
| |
| local_lock(&mlock_fbatch.lock); |
| fbatch = this_cpu_ptr(&mlock_fbatch.fbatch); |
| folio_set_mlocked(folio); |
| |
| zone_stat_mod_folio(folio, NR_MLOCK, nr_pages); |
| __count_vm_events(UNEVICTABLE_PGMLOCKED, nr_pages); |
| |
| folio_get(folio); |
| if (!folio_batch_add(fbatch, mlock_new(folio)) || |
| folio_test_large(folio) || lru_cache_disabled()) |
| mlock_folio_batch(fbatch); |
| local_unlock(&mlock_fbatch.lock); |
| } |
| |
| /** |
| * munlock_folio - munlock a folio |
| * @folio: folio to be munlocked, either normal or a THP head. |
| */ |
| void munlock_folio(struct folio *folio) |
| { |
| struct folio_batch *fbatch; |
| |
| local_lock(&mlock_fbatch.lock); |
| fbatch = this_cpu_ptr(&mlock_fbatch.fbatch); |
| /* |
| * folio_test_clear_mlocked(folio) must be left to __munlock_folio(), |
| * which will check whether the folio is multiply mlocked. |
| */ |
| folio_get(folio); |
| if (!folio_batch_add(fbatch, folio) || |
| folio_test_large(folio) || lru_cache_disabled()) |
| mlock_folio_batch(fbatch); |
| local_unlock(&mlock_fbatch.lock); |
| } |
| |
| static int mlock_pte_range(pmd_t *pmd, unsigned long addr, |
| unsigned long end, struct mm_walk *walk) |
| |
| { |
| struct vm_area_struct *vma = walk->vma; |
| spinlock_t *ptl; |
| pte_t *start_pte, *pte; |
| struct folio *folio; |
| |
| ptl = pmd_trans_huge_lock(pmd, vma); |
| if (ptl) { |
| if (!pmd_present(*pmd)) |
| goto out; |
| if (is_huge_zero_pmd(*pmd)) |
| goto out; |
| folio = page_folio(pmd_page(*pmd)); |
| if (vma->vm_flags & VM_LOCKED) |
| mlock_folio(folio); |
| else |
| munlock_folio(folio); |
| goto out; |
| } |
| |
| start_pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); |
| for (pte = start_pte; addr != end; pte++, addr += PAGE_SIZE) { |
| if (!pte_present(*pte)) |
| continue; |
| folio = vm_normal_folio(vma, addr, *pte); |
| if (!folio || folio_is_zone_device(folio)) |
| continue; |
| if (folio_test_large(folio)) |
| continue; |
| if (vma->vm_flags & VM_LOCKED) |
| mlock_folio(folio); |
| else |
| munlock_folio(folio); |
| } |
| pte_unmap(start_pte); |
| out: |
| spin_unlock(ptl); |
| cond_resched(); |
| return 0; |
| } |
| |
| /* |
| * mlock_vma_pages_range() - mlock any pages already in the range, |
| * or munlock all pages in the range. |
| * @vma - vma containing range to be mlock()ed or munlock()ed |
| * @start - start address in @vma of the range |
| * @end - end of range in @vma |
| * @newflags - the new set of flags for @vma. |
| * |
| * Called for mlock(), mlock2() and mlockall(), to set @vma VM_LOCKED; |
| * called for munlock() and munlockall(), to clear VM_LOCKED from @vma. |
| */ |
| static void mlock_vma_pages_range(struct vm_area_struct *vma, |
| unsigned long start, unsigned long end, vm_flags_t newflags) |
| { |
| static const struct mm_walk_ops mlock_walk_ops = { |
| .pmd_entry = mlock_pte_range, |
| }; |
| |
| /* |
| * There is a slight chance that concurrent page migration, |
| * or page reclaim finding a page of this now-VM_LOCKED vma, |
| * will call mlock_vma_folio() and raise page's mlock_count: |
| * double counting, leaving the page unevictable indefinitely. |
| * Communicate this danger to mlock_vma_folio() with VM_IO, |
| * which is a VM_SPECIAL flag not allowed on VM_LOCKED vmas. |
| * mmap_lock is held in write mode here, so this weird |
| * combination should not be visible to other mmap_lock users; |
| * but WRITE_ONCE so rmap walkers must see VM_IO if VM_LOCKED. |
| */ |
| if (newflags & VM_LOCKED) |
| newflags |= VM_IO; |
| WRITE_ONCE(vma->vm_flags, newflags); |
| |
| lru_add_drain(); |
| walk_page_range(vma->vm_mm, start, end, &mlock_walk_ops, NULL); |
| lru_add_drain(); |
| |
| if (newflags & VM_IO) { |
| newflags &= ~VM_IO; |
| WRITE_ONCE(vma->vm_flags, newflags); |
| } |
| } |
| |
| /* |
| * mlock_fixup - handle mlock[all]/munlock[all] requests. |
| * |
| * Filters out "special" vmas -- VM_LOCKED never gets set for these, and |
| * munlock is a no-op. However, for some special vmas, we go ahead and |
| * populate the ptes. |
| * |
| * For vmas that pass the filters, merge/split as appropriate. |
| */ |
| static int mlock_fixup(struct vma_iterator *vmi, struct vm_area_struct *vma, |
| struct vm_area_struct **prev, unsigned long start, |
| unsigned long end, vm_flags_t newflags) |
| { |
| struct mm_struct *mm = vma->vm_mm; |
| pgoff_t pgoff; |
| int nr_pages; |
| int ret = 0; |
| vm_flags_t oldflags = vma->vm_flags; |
| |
| if (newflags == oldflags || (oldflags & VM_SPECIAL) || |
| is_vm_hugetlb_page(vma) || vma == get_gate_vma(current->mm) || |
| vma_is_dax(vma) || vma_is_secretmem(vma)) |
| /* don't set VM_LOCKED or VM_LOCKONFAULT and don't count */ |
| goto out; |
| |
| pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); |
| *prev = vma_merge(vmi, mm, *prev, start, end, newflags, |
| vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma), |
| vma->vm_userfaultfd_ctx, anon_vma_name(vma)); |
| if (*prev) { |
| vma = *prev; |
| goto success; |
| } |
| |
| if (start != vma->vm_start) { |
| ret = split_vma(vmi, vma, start, 1); |
| if (ret) |
| goto out; |
| } |
| |
| if (end != vma->vm_end) { |
| ret = split_vma(vmi, vma, end, 0); |
| if (ret) |
| goto out; |
| } |
| |
| success: |
| /* |
| * Keep track of amount of locked VM. |
| */ |
| nr_pages = (end - start) >> PAGE_SHIFT; |
| if (!(newflags & VM_LOCKED)) |
| nr_pages = -nr_pages; |
| else if (oldflags & VM_LOCKED) |
| nr_pages = 0; |
| mm->locked_vm += nr_pages; |
| |
| /* |
| * vm_flags is protected by the mmap_lock held in write mode. |
| * It's okay if try_to_unmap_one unmaps a page just after we |
| * set VM_LOCKED, populate_vma_page_range will bring it back. |
| */ |
| |
| if ((newflags & VM_LOCKED) && (oldflags & VM_LOCKED)) { |
| /* No work to do, and mlocking twice would be wrong */ |
| vma->vm_flags = newflags; |
| } else { |
| mlock_vma_pages_range(vma, start, end, newflags); |
| } |
| out: |
| *prev = vma; |
| return ret; |
| } |
| |
| static int apply_vma_lock_flags(unsigned long start, size_t len, |
| vm_flags_t flags) |
| { |
| unsigned long nstart, end, tmp; |
| struct vm_area_struct *vma, *prev; |
| int error; |
| VMA_ITERATOR(vmi, current->mm, start); |
| |
| VM_BUG_ON(offset_in_page(start)); |
| VM_BUG_ON(len != PAGE_ALIGN(len)); |
| end = start + len; |
| if (end < start) |
| return -EINVAL; |
| if (end == start) |
| return 0; |
| vma = vma_iter_load(&vmi); |
| if (!vma) |
| return -ENOMEM; |
| |
| prev = vma_prev(&vmi); |
| if (start > vma->vm_start) |
| prev = vma; |
| |
| nstart = start; |
| tmp = vma->vm_start; |
| for_each_vma_range(vmi, vma, end) { |
| vm_flags_t newflags; |
| |
| if (vma->vm_start != tmp) |
| return -ENOMEM; |
| |
| newflags = vma->vm_flags & VM_LOCKED_CLEAR_MASK; |
| newflags |= flags; |
| /* Here we know that vma->vm_start <= nstart < vma->vm_end. */ |
| tmp = vma->vm_end; |
| if (tmp > end) |
| tmp = end; |
| error = mlock_fixup(&vmi, vma, &prev, nstart, tmp, newflags); |
| if (error) |
| break; |
| nstart = tmp; |
| } |
| |
| if (vma_iter_end(&vmi) < end) |
| return -ENOMEM; |
| |
| return error; |
| } |
| |
| /* |
| * Go through vma areas and sum size of mlocked |
| * vma pages, as return value. |
| * Note deferred memory locking case(mlock2(,,MLOCK_ONFAULT) |
| * is also counted. |
| * Return value: previously mlocked page counts |
| */ |
| static unsigned long count_mm_mlocked_page_nr(struct mm_struct *mm, |
| unsigned long start, size_t len) |
| { |
| struct vm_area_struct *vma; |
| unsigned long count = 0; |
| unsigned long end; |
| VMA_ITERATOR(vmi, mm, start); |
| |
| /* Don't overflow past ULONG_MAX */ |
| if (unlikely(ULONG_MAX - len < start)) |
| end = ULONG_MAX; |
| else |
| end = start + len; |
| |
| for_each_vma_range(vmi, vma, end) { |
| if (vma->vm_flags & VM_LOCKED) { |
| if (start > vma->vm_start) |
| count -= (start - vma->vm_start); |
| if (end < vma->vm_end) { |
| count += end - vma->vm_start; |
| break; |
| } |
| count += vma->vm_end - vma->vm_start; |
| } |
| } |
| |
| return count >> PAGE_SHIFT; |
| } |
| |
| /* |
| * convert get_user_pages() return value to posix mlock() error |
| */ |
| static int __mlock_posix_error_return(long retval) |
| { |
| if (retval == -EFAULT) |
| retval = -ENOMEM; |
| else if (retval == -ENOMEM) |
| retval = -EAGAIN; |
| return retval; |
| } |
| |
| static __must_check int do_mlock(unsigned long start, size_t len, vm_flags_t flags) |
| { |
| unsigned long locked; |
| unsigned long lock_limit; |
| int error = -ENOMEM; |
| |
| start = untagged_addr(start); |
| |
| if (!can_do_mlock()) |
| return -EPERM; |
| |
| len = PAGE_ALIGN(len + (offset_in_page(start))); |
| start &= PAGE_MASK; |
| |
| lock_limit = rlimit(RLIMIT_MEMLOCK); |
| lock_limit >>= PAGE_SHIFT; |
| locked = len >> PAGE_SHIFT; |
| |
| if (mmap_write_lock_killable(current->mm)) |
| return -EINTR; |
| |
| locked += current->mm->locked_vm; |
| if ((locked > lock_limit) && (!capable(CAP_IPC_LOCK))) { |
| /* |
| * It is possible that the regions requested intersect with |
| * previously mlocked areas, that part area in "mm->locked_vm" |
| * should not be counted to new mlock increment count. So check |
| * and adjust locked count if necessary. |
| */ |
| locked -= count_mm_mlocked_page_nr(current->mm, |
| start, len); |
| } |
| |
| /* check against resource limits */ |
| if ((locked <= lock_limit) || capable(CAP_IPC_LOCK)) |
| error = apply_vma_lock_flags(start, len, flags); |
| |
| mmap_write_unlock(current->mm); |
| if (error) |
| return error; |
| |
| error = __mm_populate(start, len, 0); |
| if (error) |
| return __mlock_posix_error_return(error); |
| return 0; |
| } |
| |
| SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len) |
| { |
| return do_mlock(start, len, VM_LOCKED); |
| } |
| |
| SYSCALL_DEFINE3(mlock2, unsigned long, start, size_t, len, int, flags) |
| { |
| vm_flags_t vm_flags = VM_LOCKED; |
| |
| if (flags & ~MLOCK_ONFAULT) |
| return -EINVAL; |
| |
| if (flags & MLOCK_ONFAULT) |
| vm_flags |= VM_LOCKONFAULT; |
| |
| return do_mlock(start, len, vm_flags); |
| } |
| |
| SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len) |
| { |
| int ret; |
| |
| start = untagged_addr(start); |
| |
| len = PAGE_ALIGN(len + (offset_in_page(start))); |
| start &= PAGE_MASK; |
| |
| if (mmap_write_lock_killable(current->mm)) |
| return -EINTR; |
| ret = apply_vma_lock_flags(start, len, 0); |
| mmap_write_unlock(current->mm); |
| |
| return ret; |
| } |
| |
| /* |
| * Take the MCL_* flags passed into mlockall (or 0 if called from munlockall) |
| * and translate into the appropriate modifications to mm->def_flags and/or the |
| * flags for all current VMAs. |
| * |
| * There are a couple of subtleties with this. If mlockall() is called multiple |
| * times with different flags, the values do not necessarily stack. If mlockall |
| * is called once including the MCL_FUTURE flag and then a second time without |
| * it, VM_LOCKED and VM_LOCKONFAULT will be cleared from mm->def_flags. |
| */ |
| static int apply_mlockall_flags(int flags) |
| { |
| VMA_ITERATOR(vmi, current->mm, 0); |
| struct vm_area_struct *vma, *prev = NULL; |
| vm_flags_t to_add = 0; |
| |
| current->mm->def_flags &= VM_LOCKED_CLEAR_MASK; |
| if (flags & MCL_FUTURE) { |
| current->mm->def_flags |= VM_LOCKED; |
| |
| if (flags & MCL_ONFAULT) |
| current->mm->def_flags |= VM_LOCKONFAULT; |
| |
| if (!(flags & MCL_CURRENT)) |
| goto out; |
| } |
| |
| if (flags & MCL_CURRENT) { |
| to_add |= VM_LOCKED; |
| if (flags & MCL_ONFAULT) |
| to_add |= VM_LOCKONFAULT; |
| } |
| |
| for_each_vma(vmi, vma) { |
| vm_flags_t newflags; |
| |
| newflags = vma->vm_flags & VM_LOCKED_CLEAR_MASK; |
| newflags |= to_add; |
| |
| /* Ignore errors */ |
| mlock_fixup(&vmi, vma, &prev, vma->vm_start, vma->vm_end, |
| newflags); |
| cond_resched(); |
| } |
| out: |
| return 0; |
| } |
| |
| SYSCALL_DEFINE1(mlockall, int, flags) |
| { |
| unsigned long lock_limit; |
| int ret; |
| |
| if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE | MCL_ONFAULT)) || |
| flags == MCL_ONFAULT) |
| return -EINVAL; |
| |
| if (!can_do_mlock()) |
| return -EPERM; |
| |
| lock_limit = rlimit(RLIMIT_MEMLOCK); |
| lock_limit >>= PAGE_SHIFT; |
| |
| if (mmap_write_lock_killable(current->mm)) |
| return -EINTR; |
| |
| ret = -ENOMEM; |
| if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) || |
| capable(CAP_IPC_LOCK)) |
| ret = apply_mlockall_flags(flags); |
| mmap_write_unlock(current->mm); |
| if (!ret && (flags & MCL_CURRENT)) |
| mm_populate(0, TASK_SIZE); |
| |
| return ret; |
| } |
| |
| SYSCALL_DEFINE0(munlockall) |
| { |
| int ret; |
| |
| if (mmap_write_lock_killable(current->mm)) |
| return -EINTR; |
| ret = apply_mlockall_flags(0); |
| mmap_write_unlock(current->mm); |
| return ret; |
| } |
| |
| /* |
| * Objects with different lifetime than processes (SHM_LOCK and SHM_HUGETLB |
| * shm segments) get accounted against the user_struct instead. |
| */ |
| static DEFINE_SPINLOCK(shmlock_user_lock); |
| |
| int user_shm_lock(size_t size, struct ucounts *ucounts) |
| { |
| unsigned long lock_limit, locked; |
| long memlock; |
| int allowed = 0; |
| |
| locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| lock_limit = rlimit(RLIMIT_MEMLOCK); |
| if (lock_limit != RLIM_INFINITY) |
| lock_limit >>= PAGE_SHIFT; |
| spin_lock(&shmlock_user_lock); |
| memlock = inc_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked); |
| |
| if ((memlock == LONG_MAX || memlock > lock_limit) && !capable(CAP_IPC_LOCK)) { |
| dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked); |
| goto out; |
| } |
| if (!get_ucounts(ucounts)) { |
| dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked); |
| allowed = 0; |
| goto out; |
| } |
| allowed = 1; |
| out: |
| spin_unlock(&shmlock_user_lock); |
| return allowed; |
| } |
| |
| void user_shm_unlock(size_t size, struct ucounts *ucounts) |
| { |
| spin_lock(&shmlock_user_lock); |
| dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, (size + PAGE_SIZE - 1) >> PAGE_SHIFT); |
| spin_unlock(&shmlock_user_lock); |
| put_ucounts(ucounts); |
| } |