Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * 2002-10-18 written by Jim Houston jim.houston@ccur.com |
| 3 | * Copyright (C) 2002 by Concurrent Computer Corporation |
| 4 | * Distributed under the GNU GPL license version 2. |
| 5 | * |
| 6 | * Modified by George Anzinger to reuse immediately and to use |
| 7 | * find bit instructions. Also removed _irq on spinlocks. |
| 8 | * |
Nadia Derbey | 3219b3b | 2008-07-25 01:48:00 -0700 | [diff] [blame] | 9 | * Modified by Nadia Derbey to make it RCU safe. |
| 10 | * |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 11 | * Small id to pointer translation service. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 12 | * |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 13 | * It uses a radix tree like structure as a sparse array indexed |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 14 | * by the id to obtain the pointer. The bitmap makes allocating |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 15 | * a new id quick. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 16 | * |
| 17 | * You call it to allocate an id (an int) an associate with that id a |
| 18 | * pointer or what ever, we treat it as a (void *). You can pass this |
| 19 | * id to a user for him to pass back at a later time. You then pass |
| 20 | * that id to this code and it returns your pointer. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 21 | */ |
| 22 | |
| 23 | #ifndef TEST // to test in user space... |
| 24 | #include <linux/slab.h> |
| 25 | #include <linux/init.h> |
Paul Gortmaker | 8bc3bcc | 2011-11-16 21:29:17 -0500 | [diff] [blame] | 26 | #include <linux/export.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 27 | #endif |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 28 | #include <linux/err.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | #include <linux/string.h> |
| 30 | #include <linux/idr.h> |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 31 | #include <linux/spinlock.h> |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 32 | #include <linux/percpu.h> |
| 33 | #include <linux/hardirq.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | |
Tejun Heo | e8c8d1b | 2013-02-27 17:05:04 -0800 | [diff] [blame] | 35 | #define MAX_IDR_SHIFT (sizeof(int) * 8 - 1) |
| 36 | #define MAX_IDR_BIT (1U << MAX_IDR_SHIFT) |
| 37 | |
| 38 | /* Leave the possibility of an incomplete final layer */ |
| 39 | #define MAX_IDR_LEVEL ((MAX_IDR_SHIFT + IDR_BITS - 1) / IDR_BITS) |
| 40 | |
| 41 | /* Number of id_layer structs to leave in free list */ |
| 42 | #define MAX_IDR_FREE (MAX_IDR_LEVEL * 2) |
| 43 | |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 44 | static struct kmem_cache *idr_layer_cache; |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 45 | static DEFINE_PER_CPU(struct idr_layer *, idr_preload_head); |
| 46 | static DEFINE_PER_CPU(int, idr_preload_cnt); |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 47 | static DEFINE_SPINLOCK(simple_ida_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 48 | |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 49 | /* the maximum ID which can be allocated given idr->layers */ |
| 50 | static int idr_max(int layers) |
| 51 | { |
| 52 | int bits = min_t(int, layers * IDR_BITS, MAX_IDR_SHIFT); |
| 53 | |
| 54 | return (1 << bits) - 1; |
| 55 | } |
| 56 | |
Tejun Heo | 54616283 | 2013-02-27 17:05:07 -0800 | [diff] [blame] | 57 | /* |
| 58 | * Prefix mask for an idr_layer at @layer. For layer 0, the prefix mask is |
| 59 | * all bits except for the lower IDR_BITS. For layer 1, 2 * IDR_BITS, and |
| 60 | * so on. |
| 61 | */ |
| 62 | static int idr_layer_prefix_mask(int layer) |
| 63 | { |
| 64 | return ~idr_max(layer + 1); |
| 65 | } |
| 66 | |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 67 | static struct idr_layer *get_from_free_list(struct idr *idp) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 68 | { |
| 69 | struct idr_layer *p; |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 70 | unsigned long flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 71 | |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 72 | spin_lock_irqsave(&idp->lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 73 | if ((p = idp->id_free)) { |
| 74 | idp->id_free = p->ary[0]; |
| 75 | idp->id_free_cnt--; |
| 76 | p->ary[0] = NULL; |
| 77 | } |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 78 | spin_unlock_irqrestore(&idp->lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 79 | return(p); |
| 80 | } |
| 81 | |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 82 | /** |
| 83 | * idr_layer_alloc - allocate a new idr_layer |
| 84 | * @gfp_mask: allocation mask |
| 85 | * @layer_idr: optional idr to allocate from |
| 86 | * |
| 87 | * If @layer_idr is %NULL, directly allocate one using @gfp_mask or fetch |
| 88 | * one from the per-cpu preload buffer. If @layer_idr is not %NULL, fetch |
| 89 | * an idr_layer from @idr->id_free. |
| 90 | * |
| 91 | * @layer_idr is to maintain backward compatibility with the old alloc |
| 92 | * interface - idr_pre_get() and idr_get_new*() - and will be removed |
| 93 | * together with per-pool preload buffer. |
| 94 | */ |
| 95 | static struct idr_layer *idr_layer_alloc(gfp_t gfp_mask, struct idr *layer_idr) |
| 96 | { |
| 97 | struct idr_layer *new; |
| 98 | |
| 99 | /* this is the old path, bypass to get_from_free_list() */ |
| 100 | if (layer_idr) |
| 101 | return get_from_free_list(layer_idr); |
| 102 | |
Tejun Heo | 59bfbcf | 2013-03-13 14:59:49 -0700 | [diff] [blame] | 103 | /* |
| 104 | * Try to allocate directly from kmem_cache. We want to try this |
| 105 | * before preload buffer; otherwise, non-preloading idr_alloc() |
| 106 | * users will end up taking advantage of preloading ones. As the |
| 107 | * following is allowed to fail for preloaded cases, suppress |
| 108 | * warning this time. |
| 109 | */ |
| 110 | new = kmem_cache_zalloc(idr_layer_cache, gfp_mask | __GFP_NOWARN); |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 111 | if (new) |
| 112 | return new; |
| 113 | |
| 114 | /* |
| 115 | * Try to fetch one from the per-cpu preload buffer if in process |
| 116 | * context. See idr_preload() for details. |
| 117 | */ |
Tejun Heo | 59bfbcf | 2013-03-13 14:59:49 -0700 | [diff] [blame] | 118 | if (!in_interrupt()) { |
| 119 | preempt_disable(); |
| 120 | new = __this_cpu_read(idr_preload_head); |
| 121 | if (new) { |
| 122 | __this_cpu_write(idr_preload_head, new->ary[0]); |
| 123 | __this_cpu_dec(idr_preload_cnt); |
| 124 | new->ary[0] = NULL; |
| 125 | } |
| 126 | preempt_enable(); |
| 127 | if (new) |
| 128 | return new; |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 129 | } |
Tejun Heo | 59bfbcf | 2013-03-13 14:59:49 -0700 | [diff] [blame] | 130 | |
| 131 | /* |
| 132 | * Both failed. Try kmem_cache again w/o adding __GFP_NOWARN so |
| 133 | * that memory allocation failure warning is printed as intended. |
| 134 | */ |
| 135 | return kmem_cache_zalloc(idr_layer_cache, gfp_mask); |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 136 | } |
| 137 | |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 138 | static void idr_layer_rcu_free(struct rcu_head *head) |
| 139 | { |
| 140 | struct idr_layer *layer; |
| 141 | |
| 142 | layer = container_of(head, struct idr_layer, rcu_head); |
| 143 | kmem_cache_free(idr_layer_cache, layer); |
| 144 | } |
| 145 | |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 146 | static inline void free_layer(struct idr *idr, struct idr_layer *p) |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 147 | { |
Lai Jiangshan | 15f3ec3 | 2014-06-06 14:37:14 -0700 | [diff] [blame] | 148 | if (idr->hint == p) |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 149 | RCU_INIT_POINTER(idr->hint, NULL); |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 150 | call_rcu(&p->rcu_head, idr_layer_rcu_free); |
| 151 | } |
| 152 | |
Sonny Rao | 1eec005 | 2006-06-25 05:49:34 -0700 | [diff] [blame] | 153 | /* only called when idp->lock is held */ |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 154 | static void __move_to_free_list(struct idr *idp, struct idr_layer *p) |
Sonny Rao | 1eec005 | 2006-06-25 05:49:34 -0700 | [diff] [blame] | 155 | { |
| 156 | p->ary[0] = idp->id_free; |
| 157 | idp->id_free = p; |
| 158 | idp->id_free_cnt++; |
| 159 | } |
| 160 | |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 161 | static void move_to_free_list(struct idr *idp, struct idr_layer *p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 162 | { |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 163 | unsigned long flags; |
| 164 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 165 | /* |
| 166 | * Depends on the return element being zeroed. |
| 167 | */ |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 168 | spin_lock_irqsave(&idp->lock, flags); |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 169 | __move_to_free_list(idp, p); |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 170 | spin_unlock_irqrestore(&idp->lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 171 | } |
| 172 | |
Tejun Heo | e33ac8b | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 173 | static void idr_mark_full(struct idr_layer **pa, int id) |
| 174 | { |
| 175 | struct idr_layer *p = pa[0]; |
| 176 | int l = 0; |
| 177 | |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 178 | __set_bit(id & IDR_MASK, p->bitmap); |
Tejun Heo | e33ac8b | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 179 | /* |
| 180 | * If this layer is full mark the bit in the layer above to |
| 181 | * show that this part of the radix tree is full. This may |
| 182 | * complete the layer above and require walking up the radix |
| 183 | * tree. |
| 184 | */ |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 185 | while (bitmap_full(p->bitmap, IDR_SIZE)) { |
Tejun Heo | e33ac8b | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 186 | if (!(p = pa[++l])) |
| 187 | break; |
| 188 | id = id >> IDR_BITS; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 189 | __set_bit((id & IDR_MASK), p->bitmap); |
Tejun Heo | e33ac8b | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 190 | } |
| 191 | } |
| 192 | |
Stephen Hemminger | 90ae3ae | 2014-04-07 15:38:52 -0700 | [diff] [blame] | 193 | static int __idr_pre_get(struct idr *idp, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 194 | { |
Fengguang Wu | 125c4c7 | 2012-10-04 17:13:15 -0700 | [diff] [blame] | 195 | while (idp->id_free_cnt < MAX_IDR_FREE) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 196 | struct idr_layer *new; |
Andrew Morton | 5b019e9 | 2009-01-15 13:51:21 -0800 | [diff] [blame] | 197 | new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 198 | if (new == NULL) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 199 | return (0); |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 200 | move_to_free_list(idp, new); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 201 | } |
| 202 | return 1; |
| 203 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 204 | |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 205 | /** |
| 206 | * sub_alloc - try to allocate an id without growing the tree depth |
| 207 | * @idp: idr handle |
| 208 | * @starting_id: id to start search at |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 209 | * @pa: idr_layer[MAX_IDR_LEVEL] used as backtrack buffer |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 210 | * @gfp_mask: allocation mask for idr_layer_alloc() |
| 211 | * @layer_idr: optional idr passed to idr_layer_alloc() |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 212 | * |
| 213 | * Allocate an id in range [@starting_id, INT_MAX] from @idp without |
| 214 | * growing its depth. Returns |
| 215 | * |
| 216 | * the allocated id >= 0 if successful, |
| 217 | * -EAGAIN if the tree needs to grow for allocation to succeed, |
| 218 | * -ENOSPC if the id space is exhausted, |
| 219 | * -ENOMEM if more idr_layers need to be allocated. |
| 220 | */ |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 221 | static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa, |
| 222 | gfp_t gfp_mask, struct idr *layer_idr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 223 | { |
| 224 | int n, m, sh; |
| 225 | struct idr_layer *p, *new; |
Tejun Heo | 7aae6dd | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 226 | int l, id, oid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 227 | |
| 228 | id = *starting_id; |
Tejun Heo | 7aae6dd | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 229 | restart: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 230 | p = idp->top; |
| 231 | l = idp->layers; |
| 232 | pa[l--] = NULL; |
| 233 | while (1) { |
| 234 | /* |
| 235 | * We run around this while until we reach the leaf node... |
| 236 | */ |
| 237 | n = (id >> (IDR_BITS*l)) & IDR_MASK; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 238 | m = find_next_zero_bit(p->bitmap, IDR_SIZE, n); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 239 | if (m == IDR_SIZE) { |
| 240 | /* no space available go back to previous layer. */ |
| 241 | l++; |
Tejun Heo | 7aae6dd | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 242 | oid = id; |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 243 | id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1; |
Tejun Heo | 7aae6dd | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 244 | |
| 245 | /* if already at the top layer, we need to grow */ |
Lai Jiangshan | 3afb69c | 2014-06-06 14:37:10 -0700 | [diff] [blame] | 246 | if (id > idr_max(idp->layers)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 247 | *starting_id = id; |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 248 | return -EAGAIN; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 249 | } |
Tejun Heo | d2e7276 | 2010-02-22 12:44:19 -0800 | [diff] [blame] | 250 | p = pa[l]; |
| 251 | BUG_ON(!p); |
Tejun Heo | 7aae6dd | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 252 | |
| 253 | /* If we need to go up one layer, continue the |
| 254 | * loop; otherwise, restart from the top. |
| 255 | */ |
| 256 | sh = IDR_BITS * (l + 1); |
| 257 | if (oid >> sh == id >> sh) |
| 258 | continue; |
| 259 | else |
| 260 | goto restart; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 261 | } |
| 262 | if (m != n) { |
| 263 | sh = IDR_BITS*l; |
| 264 | id = ((id >> sh) ^ n ^ m) << sh; |
| 265 | } |
Fengguang Wu | 125c4c7 | 2012-10-04 17:13:15 -0700 | [diff] [blame] | 266 | if ((id >= MAX_IDR_BIT) || (id < 0)) |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 267 | return -ENOSPC; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 268 | if (l == 0) |
| 269 | break; |
| 270 | /* |
| 271 | * Create the layer below if it is missing. |
| 272 | */ |
| 273 | if (!p->ary[m]) { |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 274 | new = idr_layer_alloc(gfp_mask, layer_idr); |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 275 | if (!new) |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 276 | return -ENOMEM; |
Manfred Spraul | 6ff2d39 | 2008-12-01 13:14:02 -0800 | [diff] [blame] | 277 | new->layer = l-1; |
Tejun Heo | 54616283 | 2013-02-27 17:05:07 -0800 | [diff] [blame] | 278 | new->prefix = id & idr_layer_prefix_mask(new->layer); |
Nadia Derbey | 3219b3b | 2008-07-25 01:48:00 -0700 | [diff] [blame] | 279 | rcu_assign_pointer(p->ary[m], new); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 280 | p->count++; |
| 281 | } |
| 282 | pa[l--] = p; |
| 283 | p = p->ary[m]; |
| 284 | } |
Tejun Heo | e33ac8b | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 285 | |
| 286 | pa[l] = p; |
| 287 | return id; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 288 | } |
| 289 | |
Tejun Heo | e33ac8b | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 290 | static int idr_get_empty_slot(struct idr *idp, int starting_id, |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 291 | struct idr_layer **pa, gfp_t gfp_mask, |
| 292 | struct idr *layer_idr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 293 | { |
| 294 | struct idr_layer *p, *new; |
| 295 | int layers, v, id; |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 296 | unsigned long flags; |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 297 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 298 | id = starting_id; |
| 299 | build_up: |
| 300 | p = idp->top; |
| 301 | layers = idp->layers; |
| 302 | if (unlikely(!p)) { |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 303 | if (!(p = idr_layer_alloc(gfp_mask, layer_idr))) |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 304 | return -ENOMEM; |
Manfred Spraul | 6ff2d39 | 2008-12-01 13:14:02 -0800 | [diff] [blame] | 305 | p->layer = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 306 | layers = 1; |
| 307 | } |
| 308 | /* |
| 309 | * Add a new layer to the top of the tree if the requested |
| 310 | * id is larger than the currently allocated space. |
| 311 | */ |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 312 | while (id > idr_max(layers)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 313 | layers++; |
Manfred Spraul | 711a49a | 2008-12-10 18:17:06 +0100 | [diff] [blame] | 314 | if (!p->count) { |
| 315 | /* special case: if the tree is currently empty, |
| 316 | * then we grow the tree by moving the top node |
| 317 | * upwards. |
| 318 | */ |
| 319 | p->layer++; |
Tejun Heo | 54616283 | 2013-02-27 17:05:07 -0800 | [diff] [blame] | 320 | WARN_ON_ONCE(p->prefix); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 321 | continue; |
Manfred Spraul | 711a49a | 2008-12-10 18:17:06 +0100 | [diff] [blame] | 322 | } |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 323 | if (!(new = idr_layer_alloc(gfp_mask, layer_idr))) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 324 | /* |
| 325 | * The allocation failed. If we built part of |
| 326 | * the structure tear it down. |
| 327 | */ |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 328 | spin_lock_irqsave(&idp->lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 329 | for (new = p; p && p != idp->top; new = p) { |
| 330 | p = p->ary[0]; |
| 331 | new->ary[0] = NULL; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 332 | new->count = 0; |
| 333 | bitmap_clear(new->bitmap, 0, IDR_SIZE); |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 334 | __move_to_free_list(idp, new); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 335 | } |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 336 | spin_unlock_irqrestore(&idp->lock, flags); |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 337 | return -ENOMEM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 338 | } |
| 339 | new->ary[0] = p; |
| 340 | new->count = 1; |
Manfred Spraul | 6ff2d39 | 2008-12-01 13:14:02 -0800 | [diff] [blame] | 341 | new->layer = layers-1; |
Tejun Heo | 54616283 | 2013-02-27 17:05:07 -0800 | [diff] [blame] | 342 | new->prefix = id & idr_layer_prefix_mask(new->layer); |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 343 | if (bitmap_full(p->bitmap, IDR_SIZE)) |
| 344 | __set_bit(0, new->bitmap); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 345 | p = new; |
| 346 | } |
Nadia Derbey | 3219b3b | 2008-07-25 01:48:00 -0700 | [diff] [blame] | 347 | rcu_assign_pointer(idp->top, p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 348 | idp->layers = layers; |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 349 | v = sub_alloc(idp, &id, pa, gfp_mask, layer_idr); |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 350 | if (v == -EAGAIN) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 351 | goto build_up; |
| 352 | return(v); |
| 353 | } |
| 354 | |
Tejun Heo | 3594eb2 | 2013-02-27 17:03:54 -0800 | [diff] [blame] | 355 | /* |
| 356 | * @id and @pa are from a successful allocation from idr_get_empty_slot(). |
| 357 | * Install the user pointer @ptr and mark the slot full. |
| 358 | */ |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 359 | static void idr_fill_slot(struct idr *idr, void *ptr, int id, |
| 360 | struct idr_layer **pa) |
Tejun Heo | e33ac8b | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 361 | { |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 362 | /* update hint used for lookup, cleared from free_layer() */ |
| 363 | rcu_assign_pointer(idr->hint, pa[0]); |
| 364 | |
Tejun Heo | 3594eb2 | 2013-02-27 17:03:54 -0800 | [diff] [blame] | 365 | rcu_assign_pointer(pa[0]->ary[id & IDR_MASK], (struct idr_layer *)ptr); |
| 366 | pa[0]->count++; |
| 367 | idr_mark_full(pa, id); |
Tejun Heo | e33ac8b | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 368 | } |
| 369 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 370 | |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 371 | /** |
| 372 | * idr_preload - preload for idr_alloc() |
| 373 | * @gfp_mask: allocation mask to use for preloading |
| 374 | * |
| 375 | * Preload per-cpu layer buffer for idr_alloc(). Can only be used from |
| 376 | * process context and each idr_preload() invocation should be matched with |
| 377 | * idr_preload_end(). Note that preemption is disabled while preloaded. |
| 378 | * |
| 379 | * The first idr_alloc() in the preloaded section can be treated as if it |
| 380 | * were invoked with @gfp_mask used for preloading. This allows using more |
| 381 | * permissive allocation masks for idrs protected by spinlocks. |
| 382 | * |
| 383 | * For example, if idr_alloc() below fails, the failure can be treated as |
| 384 | * if idr_alloc() were called with GFP_KERNEL rather than GFP_NOWAIT. |
| 385 | * |
| 386 | * idr_preload(GFP_KERNEL); |
| 387 | * spin_lock(lock); |
| 388 | * |
| 389 | * id = idr_alloc(idr, ptr, start, end, GFP_NOWAIT); |
| 390 | * |
| 391 | * spin_unlock(lock); |
| 392 | * idr_preload_end(); |
| 393 | * if (id < 0) |
| 394 | * error; |
| 395 | */ |
| 396 | void idr_preload(gfp_t gfp_mask) |
| 397 | { |
| 398 | /* |
| 399 | * Consuming preload buffer from non-process context breaks preload |
| 400 | * allocation guarantee. Disallow usage from those contexts. |
| 401 | */ |
| 402 | WARN_ON_ONCE(in_interrupt()); |
| 403 | might_sleep_if(gfp_mask & __GFP_WAIT); |
| 404 | |
| 405 | preempt_disable(); |
| 406 | |
| 407 | /* |
| 408 | * idr_alloc() is likely to succeed w/o full idr_layer buffer and |
| 409 | * return value from idr_alloc() needs to be checked for failure |
| 410 | * anyway. Silently give up if allocation fails. The caller can |
| 411 | * treat failures from idr_alloc() as if idr_alloc() were called |
| 412 | * with @gfp_mask which should be enough. |
| 413 | */ |
| 414 | while (__this_cpu_read(idr_preload_cnt) < MAX_IDR_FREE) { |
| 415 | struct idr_layer *new; |
| 416 | |
| 417 | preempt_enable(); |
| 418 | new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); |
| 419 | preempt_disable(); |
| 420 | if (!new) |
| 421 | break; |
| 422 | |
| 423 | /* link the new one to per-cpu preload list */ |
| 424 | new->ary[0] = __this_cpu_read(idr_preload_head); |
| 425 | __this_cpu_write(idr_preload_head, new); |
| 426 | __this_cpu_inc(idr_preload_cnt); |
| 427 | } |
| 428 | } |
| 429 | EXPORT_SYMBOL(idr_preload); |
| 430 | |
| 431 | /** |
| 432 | * idr_alloc - allocate new idr entry |
| 433 | * @idr: the (initialized) idr |
| 434 | * @ptr: pointer to be associated with the new id |
| 435 | * @start: the minimum id (inclusive) |
| 436 | * @end: the maximum id (exclusive, <= 0 for max) |
| 437 | * @gfp_mask: memory allocation flags |
| 438 | * |
| 439 | * Allocate an id in [start, end) and associate it with @ptr. If no ID is |
| 440 | * available in the specified range, returns -ENOSPC. On memory allocation |
| 441 | * failure, returns -ENOMEM. |
| 442 | * |
| 443 | * Note that @end is treated as max when <= 0. This is to always allow |
| 444 | * using @start + N as @end as long as N is inside integer range. |
| 445 | * |
| 446 | * The user is responsible for exclusively synchronizing all operations |
| 447 | * which may modify @idr. However, read-only accesses such as idr_find() |
| 448 | * or iteration can be performed under RCU read lock provided the user |
| 449 | * destroys @ptr in RCU-safe way after removal from idr. |
| 450 | */ |
| 451 | int idr_alloc(struct idr *idr, void *ptr, int start, int end, gfp_t gfp_mask) |
| 452 | { |
| 453 | int max = end > 0 ? end - 1 : INT_MAX; /* inclusive upper limit */ |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 454 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 455 | int id; |
| 456 | |
| 457 | might_sleep_if(gfp_mask & __GFP_WAIT); |
| 458 | |
| 459 | /* sanity checks */ |
| 460 | if (WARN_ON_ONCE(start < 0)) |
| 461 | return -EINVAL; |
| 462 | if (unlikely(max < start)) |
| 463 | return -ENOSPC; |
| 464 | |
| 465 | /* allocate id */ |
| 466 | id = idr_get_empty_slot(idr, start, pa, gfp_mask, NULL); |
| 467 | if (unlikely(id < 0)) |
| 468 | return id; |
| 469 | if (unlikely(id > max)) |
| 470 | return -ENOSPC; |
| 471 | |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 472 | idr_fill_slot(idr, ptr, id, pa); |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 473 | return id; |
| 474 | } |
| 475 | EXPORT_SYMBOL_GPL(idr_alloc); |
| 476 | |
Jeff Layton | 3e6628c4 | 2013-04-29 16:21:16 -0700 | [diff] [blame] | 477 | /** |
| 478 | * idr_alloc_cyclic - allocate new idr entry in a cyclical fashion |
| 479 | * @idr: the (initialized) idr |
| 480 | * @ptr: pointer to be associated with the new id |
| 481 | * @start: the minimum id (inclusive) |
| 482 | * @end: the maximum id (exclusive, <= 0 for max) |
| 483 | * @gfp_mask: memory allocation flags |
| 484 | * |
| 485 | * Essentially the same as idr_alloc, but prefers to allocate progressively |
| 486 | * higher ids if it can. If the "cur" counter wraps, then it will start again |
| 487 | * at the "start" end of the range and allocate one that has already been used. |
| 488 | */ |
| 489 | int idr_alloc_cyclic(struct idr *idr, void *ptr, int start, int end, |
| 490 | gfp_t gfp_mask) |
| 491 | { |
| 492 | int id; |
| 493 | |
| 494 | id = idr_alloc(idr, ptr, max(start, idr->cur), end, gfp_mask); |
| 495 | if (id == -ENOSPC) |
| 496 | id = idr_alloc(idr, ptr, start, end, gfp_mask); |
| 497 | |
| 498 | if (likely(id >= 0)) |
| 499 | idr->cur = id + 1; |
| 500 | return id; |
| 501 | } |
| 502 | EXPORT_SYMBOL(idr_alloc_cyclic); |
| 503 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 504 | static void idr_remove_warning(int id) |
| 505 | { |
Jean Delvare | dd04b45 | 2013-07-03 15:08:47 -0700 | [diff] [blame] | 506 | WARN(1, "idr_remove called for id=%d which is not allocated.\n", id); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 507 | } |
| 508 | |
| 509 | static void sub_remove(struct idr *idp, int shift, int id) |
| 510 | { |
| 511 | struct idr_layer *p = idp->top; |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 512 | struct idr_layer **pa[MAX_IDR_LEVEL + 1]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 513 | struct idr_layer ***paa = &pa[0]; |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 514 | struct idr_layer *to_free; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 515 | int n; |
| 516 | |
| 517 | *paa = NULL; |
| 518 | *++paa = &idp->top; |
| 519 | |
| 520 | while ((shift > 0) && p) { |
| 521 | n = (id >> shift) & IDR_MASK; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 522 | __clear_bit(n, p->bitmap); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 523 | *++paa = &p->ary[n]; |
| 524 | p = p->ary[n]; |
| 525 | shift -= IDR_BITS; |
| 526 | } |
| 527 | n = id & IDR_MASK; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 528 | if (likely(p != NULL && test_bit(n, p->bitmap))) { |
| 529 | __clear_bit(n, p->bitmap); |
Monam Agarwal | 3f59b06 | 2014-04-07 15:38:54 -0700 | [diff] [blame] | 530 | RCU_INIT_POINTER(p->ary[n], NULL); |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 531 | to_free = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 532 | while(*paa && ! --((**paa)->count)){ |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 533 | if (to_free) |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 534 | free_layer(idp, to_free); |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 535 | to_free = **paa; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 536 | **paa-- = NULL; |
| 537 | } |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 538 | if (!*paa) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 539 | idp->layers = 0; |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 540 | if (to_free) |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 541 | free_layer(idp, to_free); |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 542 | } else |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 543 | idr_remove_warning(id); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 544 | } |
| 545 | |
| 546 | /** |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 547 | * idr_remove - remove the given id and free its slot |
Robert P. J. Day | 72fd4a3 | 2007-02-10 01:45:59 -0800 | [diff] [blame] | 548 | * @idp: idr handle |
| 549 | * @id: unique key |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 550 | */ |
| 551 | void idr_remove(struct idr *idp, int id) |
| 552 | { |
| 553 | struct idr_layer *p; |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 554 | struct idr_layer *to_free; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 555 | |
Tejun Heo | 2e1c9b2 | 2013-03-08 12:43:30 -0800 | [diff] [blame] | 556 | if (id < 0) |
Tejun Heo | e8c8d1b | 2013-02-27 17:05:04 -0800 | [diff] [blame] | 557 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 558 | |
Lai Jiangshan | 8f9f665 | 2014-06-06 14:37:11 -0700 | [diff] [blame] | 559 | if (id > idr_max(idp->layers)) { |
| 560 | idr_remove_warning(id); |
| 561 | return; |
| 562 | } |
| 563 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 564 | sub_remove(idp, (idp->layers - 1) * IDR_BITS, id); |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 565 | if (idp->top && idp->top->count == 1 && (idp->layers > 1) && |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 566 | idp->top->ary[0]) { |
| 567 | /* |
| 568 | * Single child at leftmost slot: we can shrink the tree. |
| 569 | * This level is not needed anymore since when layers are |
| 570 | * inserted, they are inserted at the top of the existing |
| 571 | * tree. |
| 572 | */ |
| 573 | to_free = idp->top; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 574 | p = idp->top->ary[0]; |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 575 | rcu_assign_pointer(idp->top, p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 576 | --idp->layers; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 577 | to_free->count = 0; |
| 578 | bitmap_clear(to_free->bitmap, 0, IDR_SIZE); |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 579 | free_layer(idp, to_free); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 580 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 581 | } |
| 582 | EXPORT_SYMBOL(idr_remove); |
| 583 | |
Stephen Hemminger | 90ae3ae | 2014-04-07 15:38:52 -0700 | [diff] [blame] | 584 | static void __idr_remove_all(struct idr *idp) |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 585 | { |
Oleg Nesterov | 6ace06dc | 2007-07-31 00:39:19 -0700 | [diff] [blame] | 586 | int n, id, max; |
Imre Deak | 2dcb22b | 2010-05-26 14:43:38 -0700 | [diff] [blame] | 587 | int bt_mask; |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 588 | struct idr_layer *p; |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 589 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 590 | struct idr_layer **paa = &pa[0]; |
| 591 | |
| 592 | n = idp->layers * IDR_BITS; |
Andrey Ryabinin | 93b7aca | 2014-08-08 14:22:07 -0700 | [diff] [blame] | 593 | *paa = idp->top; |
Monam Agarwal | 3f59b06 | 2014-04-07 15:38:54 -0700 | [diff] [blame] | 594 | RCU_INIT_POINTER(idp->top, NULL); |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 595 | max = idr_max(idp->layers); |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 596 | |
| 597 | id = 0; |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 598 | while (id >= 0 && id <= max) { |
Andrey Ryabinin | 93b7aca | 2014-08-08 14:22:07 -0700 | [diff] [blame] | 599 | p = *paa; |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 600 | while (n > IDR_BITS && p) { |
| 601 | n -= IDR_BITS; |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 602 | p = p->ary[(id >> n) & IDR_MASK]; |
Andrey Ryabinin | 93b7aca | 2014-08-08 14:22:07 -0700 | [diff] [blame] | 603 | *++paa = p; |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 604 | } |
| 605 | |
Imre Deak | 2dcb22b | 2010-05-26 14:43:38 -0700 | [diff] [blame] | 606 | bt_mask = id; |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 607 | id += 1 << n; |
Imre Deak | 2dcb22b | 2010-05-26 14:43:38 -0700 | [diff] [blame] | 608 | /* Get the highest bit that the above add changed from 0->1. */ |
| 609 | while (n < fls(id ^ bt_mask)) { |
Andrey Ryabinin | 93b7aca | 2014-08-08 14:22:07 -0700 | [diff] [blame] | 610 | if (*paa) |
| 611 | free_layer(idp, *paa); |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 612 | n += IDR_BITS; |
Andrey Ryabinin | 93b7aca | 2014-08-08 14:22:07 -0700 | [diff] [blame] | 613 | --paa; |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 614 | } |
| 615 | } |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 616 | idp->layers = 0; |
| 617 | } |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 618 | |
| 619 | /** |
Andrew Morton | 8d3b359 | 2005-10-23 12:57:18 -0700 | [diff] [blame] | 620 | * idr_destroy - release all cached layers within an idr tree |
Naohiro Aota | ea24ea850 | 2010-08-31 00:37:03 +0900 | [diff] [blame] | 621 | * @idp: idr handle |
Tejun Heo | 9bb26bc | 2013-02-27 17:03:35 -0800 | [diff] [blame] | 622 | * |
| 623 | * Free all id mappings and all idp_layers. After this function, @idp is |
| 624 | * completely unused and can be freed / recycled. The caller is |
| 625 | * responsible for ensuring that no one else accesses @idp during or after |
| 626 | * idr_destroy(). |
| 627 | * |
| 628 | * A typical clean-up sequence for objects stored in an idr tree will use |
| 629 | * idr_for_each() to free all objects, if necessay, then idr_destroy() to |
| 630 | * free up the id mappings and cached idr_layers. |
Andrew Morton | 8d3b359 | 2005-10-23 12:57:18 -0700 | [diff] [blame] | 631 | */ |
| 632 | void idr_destroy(struct idr *idp) |
| 633 | { |
Tejun Heo | fe6e24e | 2013-02-27 17:03:50 -0800 | [diff] [blame] | 634 | __idr_remove_all(idp); |
Tejun Heo | 9bb26bc | 2013-02-27 17:03:35 -0800 | [diff] [blame] | 635 | |
Andrew Morton | 8d3b359 | 2005-10-23 12:57:18 -0700 | [diff] [blame] | 636 | while (idp->id_free_cnt) { |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 637 | struct idr_layer *p = get_from_free_list(idp); |
Andrew Morton | 8d3b359 | 2005-10-23 12:57:18 -0700 | [diff] [blame] | 638 | kmem_cache_free(idr_layer_cache, p); |
| 639 | } |
| 640 | } |
| 641 | EXPORT_SYMBOL(idr_destroy); |
| 642 | |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 643 | void *idr_find_slowpath(struct idr *idp, int id) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 644 | { |
| 645 | int n; |
| 646 | struct idr_layer *p; |
| 647 | |
Tejun Heo | 2e1c9b2 | 2013-03-08 12:43:30 -0800 | [diff] [blame] | 648 | if (id < 0) |
Tejun Heo | e8c8d1b | 2013-02-27 17:05:04 -0800 | [diff] [blame] | 649 | return NULL; |
| 650 | |
Paul E. McKenney | 96be753 | 2010-02-22 17:04:55 -0800 | [diff] [blame] | 651 | p = rcu_dereference_raw(idp->top); |
Manfred Spraul | 6ff2d39 | 2008-12-01 13:14:02 -0800 | [diff] [blame] | 652 | if (!p) |
| 653 | return NULL; |
| 654 | n = (p->layer+1) * IDR_BITS; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 655 | |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 656 | if (id > idr_max(p->layer + 1)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 657 | return NULL; |
Manfred Spraul | 6ff2d39 | 2008-12-01 13:14:02 -0800 | [diff] [blame] | 658 | BUG_ON(n == 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 659 | |
| 660 | while (n > 0 && p) { |
| 661 | n -= IDR_BITS; |
Manfred Spraul | 6ff2d39 | 2008-12-01 13:14:02 -0800 | [diff] [blame] | 662 | BUG_ON(n != p->layer*IDR_BITS); |
Paul E. McKenney | 96be753 | 2010-02-22 17:04:55 -0800 | [diff] [blame] | 663 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 664 | } |
| 665 | return((void *)p); |
| 666 | } |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 667 | EXPORT_SYMBOL(idr_find_slowpath); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 668 | |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 669 | /** |
Kristian Hoegsberg | 96d7fa4 | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 670 | * idr_for_each - iterate through all stored pointers |
| 671 | * @idp: idr handle |
| 672 | * @fn: function to be called for each pointer |
| 673 | * @data: data passed back to callback function |
| 674 | * |
| 675 | * Iterate over the pointers registered with the given idr. The |
| 676 | * callback function will be called for each pointer currently |
| 677 | * registered, passing the id, the pointer and the data pointer passed |
| 678 | * to this function. It is not safe to modify the idr tree while in |
| 679 | * the callback, so functions such as idr_get_new and idr_remove are |
| 680 | * not allowed. |
| 681 | * |
| 682 | * We check the return of @fn each time. If it returns anything other |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 683 | * than %0, we break out and return that value. |
Kristian Hoegsberg | 96d7fa4 | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 684 | * |
| 685 | * The caller must serialize idr_for_each() vs idr_get_new() and idr_remove(). |
| 686 | */ |
| 687 | int idr_for_each(struct idr *idp, |
| 688 | int (*fn)(int id, void *p, void *data), void *data) |
| 689 | { |
| 690 | int n, id, max, error = 0; |
| 691 | struct idr_layer *p; |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 692 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
Kristian Hoegsberg | 96d7fa4 | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 693 | struct idr_layer **paa = &pa[0]; |
| 694 | |
| 695 | n = idp->layers * IDR_BITS; |
Andrey Ryabinin | 93b7aca | 2014-08-08 14:22:07 -0700 | [diff] [blame] | 696 | *paa = rcu_dereference_raw(idp->top); |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 697 | max = idr_max(idp->layers); |
Kristian Hoegsberg | 96d7fa4 | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 698 | |
| 699 | id = 0; |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 700 | while (id >= 0 && id <= max) { |
Andrey Ryabinin | 93b7aca | 2014-08-08 14:22:07 -0700 | [diff] [blame] | 701 | p = *paa; |
Kristian Hoegsberg | 96d7fa4 | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 702 | while (n > 0 && p) { |
| 703 | n -= IDR_BITS; |
Paul E. McKenney | 96be753 | 2010-02-22 17:04:55 -0800 | [diff] [blame] | 704 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
Andrey Ryabinin | 93b7aca | 2014-08-08 14:22:07 -0700 | [diff] [blame] | 705 | *++paa = p; |
Kristian Hoegsberg | 96d7fa4 | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 706 | } |
| 707 | |
| 708 | if (p) { |
| 709 | error = fn(id, (void *)p, data); |
| 710 | if (error) |
| 711 | break; |
| 712 | } |
| 713 | |
| 714 | id += 1 << n; |
| 715 | while (n < fls(id)) { |
| 716 | n += IDR_BITS; |
Andrey Ryabinin | 93b7aca | 2014-08-08 14:22:07 -0700 | [diff] [blame] | 717 | --paa; |
Kristian Hoegsberg | 96d7fa4 | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 718 | } |
| 719 | } |
| 720 | |
| 721 | return error; |
| 722 | } |
| 723 | EXPORT_SYMBOL(idr_for_each); |
| 724 | |
| 725 | /** |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 726 | * idr_get_next - lookup next object of id to given id. |
| 727 | * @idp: idr handle |
Naohiro Aota | ea24ea850 | 2010-08-31 00:37:03 +0900 | [diff] [blame] | 728 | * @nextidp: pointer to lookup key |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 729 | * |
| 730 | * Returns pointer to registered object with id, which is next number to |
Naohiro Aota | 1458ce1 | 2010-08-27 17:43:46 +0900 | [diff] [blame] | 731 | * given id. After being looked up, *@nextidp will be updated for the next |
| 732 | * iteration. |
Hugh Dickins | 9f7de82 | 2012-03-21 16:34:20 -0700 | [diff] [blame] | 733 | * |
| 734 | * This function can be called under rcu_read_lock(), given that the leaf |
| 735 | * pointers lifetimes are correctly managed. |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 736 | */ |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 737 | void *idr_get_next(struct idr *idp, int *nextidp) |
| 738 | { |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 739 | struct idr_layer *p, *pa[MAX_IDR_LEVEL + 1]; |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 740 | struct idr_layer **paa = &pa[0]; |
| 741 | int id = *nextidp; |
| 742 | int n, max; |
| 743 | |
| 744 | /* find first ent */ |
Andrey Ryabinin | 93b7aca | 2014-08-08 14:22:07 -0700 | [diff] [blame] | 745 | p = *paa = rcu_dereference_raw(idp->top); |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 746 | if (!p) |
| 747 | return NULL; |
Hugh Dickins | 9f7de82 | 2012-03-21 16:34:20 -0700 | [diff] [blame] | 748 | n = (p->layer + 1) * IDR_BITS; |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 749 | max = idr_max(p->layer + 1); |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 750 | |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 751 | while (id >= 0 && id <= max) { |
Andrey Ryabinin | 93b7aca | 2014-08-08 14:22:07 -0700 | [diff] [blame] | 752 | p = *paa; |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 753 | while (n > 0 && p) { |
| 754 | n -= IDR_BITS; |
Paul E. McKenney | 94bfa3b | 2010-06-07 17:09:45 -0700 | [diff] [blame] | 755 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
Andrey Ryabinin | 93b7aca | 2014-08-08 14:22:07 -0700 | [diff] [blame] | 756 | *++paa = p; |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 757 | } |
| 758 | |
| 759 | if (p) { |
| 760 | *nextidp = id; |
| 761 | return p; |
| 762 | } |
| 763 | |
Tejun Heo | 6cdae74 | 2013-02-27 17:03:34 -0800 | [diff] [blame] | 764 | /* |
| 765 | * Proceed to the next layer at the current level. Unlike |
| 766 | * idr_for_each(), @id isn't guaranteed to be aligned to |
| 767 | * layer boundary at this point and adding 1 << n may |
| 768 | * incorrectly skip IDs. Make sure we jump to the |
| 769 | * beginning of the next layer using round_up(). |
| 770 | */ |
| 771 | id = round_up(id + 1, 1 << n); |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 772 | while (n < fls(id)) { |
| 773 | n += IDR_BITS; |
Andrey Ryabinin | 93b7aca | 2014-08-08 14:22:07 -0700 | [diff] [blame] | 774 | --paa; |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 775 | } |
| 776 | } |
| 777 | return NULL; |
| 778 | } |
Ben Hutchings | 4d1ee80 | 2010-01-29 20:59:17 +0000 | [diff] [blame] | 779 | EXPORT_SYMBOL(idr_get_next); |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 780 | |
| 781 | |
| 782 | /** |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 783 | * idr_replace - replace pointer for given id |
| 784 | * @idp: idr handle |
| 785 | * @ptr: pointer you want associated with the id |
| 786 | * @id: lookup key |
| 787 | * |
| 788 | * Replace the pointer registered with an id and return the old value. |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 789 | * A %-ENOENT return indicates that @id was not found. |
| 790 | * A %-EINVAL return indicates that @id was not within valid constraints. |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 791 | * |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 792 | * The caller must serialize with writers. |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 793 | */ |
| 794 | void *idr_replace(struct idr *idp, void *ptr, int id) |
| 795 | { |
| 796 | int n; |
| 797 | struct idr_layer *p, *old_p; |
| 798 | |
Tejun Heo | 2e1c9b2 | 2013-03-08 12:43:30 -0800 | [diff] [blame] | 799 | if (id < 0) |
Tejun Heo | e8c8d1b | 2013-02-27 17:05:04 -0800 | [diff] [blame] | 800 | return ERR_PTR(-EINVAL); |
| 801 | |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 802 | p = idp->top; |
Manfred Spraul | 6ff2d39 | 2008-12-01 13:14:02 -0800 | [diff] [blame] | 803 | if (!p) |
Lai Jiangshan | b93804b | 2014-06-06 14:37:13 -0700 | [diff] [blame] | 804 | return ERR_PTR(-ENOENT); |
Manfred Spraul | 6ff2d39 | 2008-12-01 13:14:02 -0800 | [diff] [blame] | 805 | |
Lai Jiangshan | 3afb69c | 2014-06-06 14:37:10 -0700 | [diff] [blame] | 806 | if (id > idr_max(p->layer + 1)) |
Lai Jiangshan | b93804b | 2014-06-06 14:37:13 -0700 | [diff] [blame] | 807 | return ERR_PTR(-ENOENT); |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 808 | |
Lai Jiangshan | 3afb69c | 2014-06-06 14:37:10 -0700 | [diff] [blame] | 809 | n = p->layer * IDR_BITS; |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 810 | while ((n > 0) && p) { |
| 811 | p = p->ary[(id >> n) & IDR_MASK]; |
| 812 | n -= IDR_BITS; |
| 813 | } |
| 814 | |
| 815 | n = id & IDR_MASK; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 816 | if (unlikely(p == NULL || !test_bit(n, p->bitmap))) |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 817 | return ERR_PTR(-ENOENT); |
| 818 | |
| 819 | old_p = p->ary[n]; |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 820 | rcu_assign_pointer(p->ary[n], ptr); |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 821 | |
| 822 | return old_p; |
| 823 | } |
| 824 | EXPORT_SYMBOL(idr_replace); |
| 825 | |
Akinobu Mita | 199f0ca | 2008-04-29 01:03:13 -0700 | [diff] [blame] | 826 | void __init idr_init_cache(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 827 | { |
Akinobu Mita | 199f0ca | 2008-04-29 01:03:13 -0700 | [diff] [blame] | 828 | idr_layer_cache = kmem_cache_create("idr_layer_cache", |
Andrew Morton | 5b019e9 | 2009-01-15 13:51:21 -0800 | [diff] [blame] | 829 | sizeof(struct idr_layer), 0, SLAB_PANIC, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 830 | } |
| 831 | |
| 832 | /** |
| 833 | * idr_init - initialize idr handle |
| 834 | * @idp: idr handle |
| 835 | * |
| 836 | * This function is use to set up the handle (@idp) that you will pass |
| 837 | * to the rest of the functions. |
| 838 | */ |
| 839 | void idr_init(struct idr *idp) |
| 840 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 841 | memset(idp, 0, sizeof(struct idr)); |
| 842 | spin_lock_init(&idp->lock); |
| 843 | } |
| 844 | EXPORT_SYMBOL(idr_init); |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 845 | |
Andreas Gruenbacher | 05f7a7d | 2011-08-08 23:36:56 +0200 | [diff] [blame] | 846 | static int idr_has_entry(int id, void *p, void *data) |
| 847 | { |
| 848 | return 1; |
| 849 | } |
| 850 | |
| 851 | bool idr_is_empty(struct idr *idp) |
| 852 | { |
| 853 | return !idr_for_each(idp, idr_has_entry, NULL); |
| 854 | } |
| 855 | EXPORT_SYMBOL(idr_is_empty); |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 856 | |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 857 | /** |
| 858 | * DOC: IDA description |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 859 | * IDA - IDR based ID allocator |
| 860 | * |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 861 | * This is id allocator without id -> pointer translation. Memory |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 862 | * usage is much lower than full blown idr because each id only |
| 863 | * occupies a bit. ida uses a custom leaf node which contains |
| 864 | * IDA_BITMAP_BITS slots. |
| 865 | * |
| 866 | * 2007-04-25 written by Tejun Heo <htejun@gmail.com> |
| 867 | */ |
| 868 | |
| 869 | static void free_bitmap(struct ida *ida, struct ida_bitmap *bitmap) |
| 870 | { |
| 871 | unsigned long flags; |
| 872 | |
| 873 | if (!ida->free_bitmap) { |
| 874 | spin_lock_irqsave(&ida->idr.lock, flags); |
| 875 | if (!ida->free_bitmap) { |
| 876 | ida->free_bitmap = bitmap; |
| 877 | bitmap = NULL; |
| 878 | } |
| 879 | spin_unlock_irqrestore(&ida->idr.lock, flags); |
| 880 | } |
| 881 | |
| 882 | kfree(bitmap); |
| 883 | } |
| 884 | |
| 885 | /** |
| 886 | * ida_pre_get - reserve resources for ida allocation |
| 887 | * @ida: ida handle |
| 888 | * @gfp_mask: memory allocation flag |
| 889 | * |
| 890 | * This function should be called prior to locking and calling the |
| 891 | * following function. It preallocates enough memory to satisfy the |
| 892 | * worst possible allocation. |
| 893 | * |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 894 | * If the system is REALLY out of memory this function returns %0, |
| 895 | * otherwise %1. |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 896 | */ |
| 897 | int ida_pre_get(struct ida *ida, gfp_t gfp_mask) |
| 898 | { |
| 899 | /* allocate idr_layers */ |
Tejun Heo | c8615d3 | 2013-03-13 14:59:42 -0700 | [diff] [blame] | 900 | if (!__idr_pre_get(&ida->idr, gfp_mask)) |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 901 | return 0; |
| 902 | |
| 903 | /* allocate free_bitmap */ |
| 904 | if (!ida->free_bitmap) { |
| 905 | struct ida_bitmap *bitmap; |
| 906 | |
| 907 | bitmap = kmalloc(sizeof(struct ida_bitmap), gfp_mask); |
| 908 | if (!bitmap) |
| 909 | return 0; |
| 910 | |
| 911 | free_bitmap(ida, bitmap); |
| 912 | } |
| 913 | |
| 914 | return 1; |
| 915 | } |
| 916 | EXPORT_SYMBOL(ida_pre_get); |
| 917 | |
| 918 | /** |
| 919 | * ida_get_new_above - allocate new ID above or equal to a start id |
| 920 | * @ida: ida handle |
Naohiro Aota | ea24ea850 | 2010-08-31 00:37:03 +0900 | [diff] [blame] | 921 | * @starting_id: id to start search at |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 922 | * @p_id: pointer to the allocated handle |
| 923 | * |
Wang Sheng-Hui | e3816c5 | 2011-10-31 17:12:36 -0700 | [diff] [blame] | 924 | * Allocate new ID above or equal to @starting_id. It should be called |
| 925 | * with any required locks. |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 926 | * |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 927 | * If memory is required, it will return %-EAGAIN, you should unlock |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 928 | * and go back to the ida_pre_get() call. If the ida is full, it will |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 929 | * return %-ENOSPC. |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 930 | * |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 931 | * @p_id returns a value in the range @starting_id ... %0x7fffffff. |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 932 | */ |
| 933 | int ida_get_new_above(struct ida *ida, int starting_id, int *p_id) |
| 934 | { |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 935 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 936 | struct ida_bitmap *bitmap; |
| 937 | unsigned long flags; |
| 938 | int idr_id = starting_id / IDA_BITMAP_BITS; |
| 939 | int offset = starting_id % IDA_BITMAP_BITS; |
| 940 | int t, id; |
| 941 | |
| 942 | restart: |
| 943 | /* get vacant slot */ |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 944 | t = idr_get_empty_slot(&ida->idr, idr_id, pa, 0, &ida->idr); |
Nadia Derbey | 944ca05 | 2008-07-25 01:47:59 -0700 | [diff] [blame] | 945 | if (t < 0) |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 946 | return t == -ENOMEM ? -EAGAIN : t; |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 947 | |
Fengguang Wu | 125c4c7 | 2012-10-04 17:13:15 -0700 | [diff] [blame] | 948 | if (t * IDA_BITMAP_BITS >= MAX_IDR_BIT) |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 949 | return -ENOSPC; |
| 950 | |
| 951 | if (t != idr_id) |
| 952 | offset = 0; |
| 953 | idr_id = t; |
| 954 | |
| 955 | /* if bitmap isn't there, create a new one */ |
| 956 | bitmap = (void *)pa[0]->ary[idr_id & IDR_MASK]; |
| 957 | if (!bitmap) { |
| 958 | spin_lock_irqsave(&ida->idr.lock, flags); |
| 959 | bitmap = ida->free_bitmap; |
| 960 | ida->free_bitmap = NULL; |
| 961 | spin_unlock_irqrestore(&ida->idr.lock, flags); |
| 962 | |
| 963 | if (!bitmap) |
| 964 | return -EAGAIN; |
| 965 | |
| 966 | memset(bitmap, 0, sizeof(struct ida_bitmap)); |
Nadia Derbey | 3219b3b | 2008-07-25 01:48:00 -0700 | [diff] [blame] | 967 | rcu_assign_pointer(pa[0]->ary[idr_id & IDR_MASK], |
| 968 | (void *)bitmap); |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 969 | pa[0]->count++; |
| 970 | } |
| 971 | |
| 972 | /* lookup for empty slot */ |
| 973 | t = find_next_zero_bit(bitmap->bitmap, IDA_BITMAP_BITS, offset); |
| 974 | if (t == IDA_BITMAP_BITS) { |
| 975 | /* no empty slot after offset, continue to the next chunk */ |
| 976 | idr_id++; |
| 977 | offset = 0; |
| 978 | goto restart; |
| 979 | } |
| 980 | |
| 981 | id = idr_id * IDA_BITMAP_BITS + t; |
Fengguang Wu | 125c4c7 | 2012-10-04 17:13:15 -0700 | [diff] [blame] | 982 | if (id >= MAX_IDR_BIT) |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 983 | return -ENOSPC; |
| 984 | |
| 985 | __set_bit(t, bitmap->bitmap); |
| 986 | if (++bitmap->nr_busy == IDA_BITMAP_BITS) |
| 987 | idr_mark_full(pa, idr_id); |
| 988 | |
| 989 | *p_id = id; |
| 990 | |
| 991 | /* Each leaf node can handle nearly a thousand slots and the |
| 992 | * whole idea of ida is to have small memory foot print. |
| 993 | * Throw away extra resources one by one after each successful |
| 994 | * allocation. |
| 995 | */ |
| 996 | if (ida->idr.id_free_cnt || ida->free_bitmap) { |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 997 | struct idr_layer *p = get_from_free_list(&ida->idr); |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 998 | if (p) |
| 999 | kmem_cache_free(idr_layer_cache, p); |
| 1000 | } |
| 1001 | |
| 1002 | return 0; |
| 1003 | } |
| 1004 | EXPORT_SYMBOL(ida_get_new_above); |
| 1005 | |
| 1006 | /** |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 1007 | * ida_remove - remove the given ID |
| 1008 | * @ida: ida handle |
| 1009 | * @id: ID to free |
| 1010 | */ |
| 1011 | void ida_remove(struct ida *ida, int id) |
| 1012 | { |
| 1013 | struct idr_layer *p = ida->idr.top; |
| 1014 | int shift = (ida->idr.layers - 1) * IDR_BITS; |
| 1015 | int idr_id = id / IDA_BITMAP_BITS; |
| 1016 | int offset = id % IDA_BITMAP_BITS; |
| 1017 | int n; |
| 1018 | struct ida_bitmap *bitmap; |
| 1019 | |
Lai Jiangshan | 8f9f665 | 2014-06-06 14:37:11 -0700 | [diff] [blame] | 1020 | if (idr_id > idr_max(ida->idr.layers)) |
| 1021 | goto err; |
| 1022 | |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 1023 | /* clear full bits while looking up the leaf idr_layer */ |
| 1024 | while ((shift > 0) && p) { |
| 1025 | n = (idr_id >> shift) & IDR_MASK; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 1026 | __clear_bit(n, p->bitmap); |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 1027 | p = p->ary[n]; |
| 1028 | shift -= IDR_BITS; |
| 1029 | } |
| 1030 | |
| 1031 | if (p == NULL) |
| 1032 | goto err; |
| 1033 | |
| 1034 | n = idr_id & IDR_MASK; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 1035 | __clear_bit(n, p->bitmap); |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 1036 | |
| 1037 | bitmap = (void *)p->ary[n]; |
Lai Jiangshan | aef0f62 | 2014-06-06 14:37:12 -0700 | [diff] [blame] | 1038 | if (!bitmap || !test_bit(offset, bitmap->bitmap)) |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 1039 | goto err; |
| 1040 | |
| 1041 | /* update bitmap and remove it if empty */ |
| 1042 | __clear_bit(offset, bitmap->bitmap); |
| 1043 | if (--bitmap->nr_busy == 0) { |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 1044 | __set_bit(n, p->bitmap); /* to please idr_remove() */ |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 1045 | idr_remove(&ida->idr, idr_id); |
| 1046 | free_bitmap(ida, bitmap); |
| 1047 | } |
| 1048 | |
| 1049 | return; |
| 1050 | |
| 1051 | err: |
Jean Delvare | dd04b45 | 2013-07-03 15:08:47 -0700 | [diff] [blame] | 1052 | WARN(1, "ida_remove called for id=%d which is not allocated.\n", id); |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 1053 | } |
| 1054 | EXPORT_SYMBOL(ida_remove); |
| 1055 | |
| 1056 | /** |
| 1057 | * ida_destroy - release all cached layers within an ida tree |
Naohiro Aota | ea24ea850 | 2010-08-31 00:37:03 +0900 | [diff] [blame] | 1058 | * @ida: ida handle |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 1059 | */ |
| 1060 | void ida_destroy(struct ida *ida) |
| 1061 | { |
| 1062 | idr_destroy(&ida->idr); |
| 1063 | kfree(ida->free_bitmap); |
| 1064 | } |
| 1065 | EXPORT_SYMBOL(ida_destroy); |
| 1066 | |
| 1067 | /** |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 1068 | * ida_simple_get - get a new id. |
| 1069 | * @ida: the (initialized) ida. |
| 1070 | * @start: the minimum id (inclusive, < 0x8000000) |
| 1071 | * @end: the maximum id (exclusive, < 0x8000000 or 0) |
| 1072 | * @gfp_mask: memory allocation flags |
| 1073 | * |
| 1074 | * Allocates an id in the range start <= id < end, or returns -ENOSPC. |
| 1075 | * On memory allocation failure, returns -ENOMEM. |
| 1076 | * |
| 1077 | * Use ida_simple_remove() to get rid of an id. |
| 1078 | */ |
| 1079 | int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end, |
| 1080 | gfp_t gfp_mask) |
| 1081 | { |
| 1082 | int ret, id; |
| 1083 | unsigned int max; |
Tejun Heo | 46cbc1d | 2011-11-02 13:38:46 -0700 | [diff] [blame] | 1084 | unsigned long flags; |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 1085 | |
| 1086 | BUG_ON((int)start < 0); |
| 1087 | BUG_ON((int)end < 0); |
| 1088 | |
| 1089 | if (end == 0) |
| 1090 | max = 0x80000000; |
| 1091 | else { |
| 1092 | BUG_ON(end < start); |
| 1093 | max = end - 1; |
| 1094 | } |
| 1095 | |
| 1096 | again: |
| 1097 | if (!ida_pre_get(ida, gfp_mask)) |
| 1098 | return -ENOMEM; |
| 1099 | |
Tejun Heo | 46cbc1d | 2011-11-02 13:38:46 -0700 | [diff] [blame] | 1100 | spin_lock_irqsave(&simple_ida_lock, flags); |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 1101 | ret = ida_get_new_above(ida, start, &id); |
| 1102 | if (!ret) { |
| 1103 | if (id > max) { |
| 1104 | ida_remove(ida, id); |
| 1105 | ret = -ENOSPC; |
| 1106 | } else { |
| 1107 | ret = id; |
| 1108 | } |
| 1109 | } |
Tejun Heo | 46cbc1d | 2011-11-02 13:38:46 -0700 | [diff] [blame] | 1110 | spin_unlock_irqrestore(&simple_ida_lock, flags); |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 1111 | |
| 1112 | if (unlikely(ret == -EAGAIN)) |
| 1113 | goto again; |
| 1114 | |
| 1115 | return ret; |
| 1116 | } |
| 1117 | EXPORT_SYMBOL(ida_simple_get); |
| 1118 | |
| 1119 | /** |
| 1120 | * ida_simple_remove - remove an allocated id. |
| 1121 | * @ida: the (initialized) ida. |
| 1122 | * @id: the id returned by ida_simple_get. |
| 1123 | */ |
| 1124 | void ida_simple_remove(struct ida *ida, unsigned int id) |
| 1125 | { |
Tejun Heo | 46cbc1d | 2011-11-02 13:38:46 -0700 | [diff] [blame] | 1126 | unsigned long flags; |
| 1127 | |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 1128 | BUG_ON((int)id < 0); |
Tejun Heo | 46cbc1d | 2011-11-02 13:38:46 -0700 | [diff] [blame] | 1129 | spin_lock_irqsave(&simple_ida_lock, flags); |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 1130 | ida_remove(ida, id); |
Tejun Heo | 46cbc1d | 2011-11-02 13:38:46 -0700 | [diff] [blame] | 1131 | spin_unlock_irqrestore(&simple_ida_lock, flags); |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 1132 | } |
| 1133 | EXPORT_SYMBOL(ida_simple_remove); |
| 1134 | |
| 1135 | /** |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 1136 | * ida_init - initialize ida handle |
| 1137 | * @ida: ida handle |
| 1138 | * |
| 1139 | * This function is use to set up the handle (@ida) that you will pass |
| 1140 | * to the rest of the functions. |
| 1141 | */ |
| 1142 | void ida_init(struct ida *ida) |
| 1143 | { |
| 1144 | memset(ida, 0, sizeof(struct ida)); |
| 1145 | idr_init(&ida->idr); |
| 1146 | |
| 1147 | } |
| 1148 | EXPORT_SYMBOL(ida_init); |