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. |
| 21 | |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 22 | * You can release ids at any time. When all ids are released, most of |
Fengguang Wu | 125c4c7 | 2012-10-04 17:13:15 -0700 | [diff] [blame] | 23 | * the memory is returned (we keep MAX_IDR_FREE) in a local pool so we |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 24 | * don't need to go to the memory "store" during an id allocate, just |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 25 | * so you don't need to be too concerned about locking and conflicts |
| 26 | * with the slab allocator. |
| 27 | */ |
| 28 | |
| 29 | #ifndef TEST // to test in user space... |
| 30 | #include <linux/slab.h> |
| 31 | #include <linux/init.h> |
Paul Gortmaker | 8bc3bcc | 2011-11-16 21:29:17 -0500 | [diff] [blame] | 32 | #include <linux/export.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 33 | #endif |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 34 | #include <linux/err.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | #include <linux/string.h> |
| 36 | #include <linux/idr.h> |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 37 | #include <linux/spinlock.h> |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 38 | #include <linux/percpu.h> |
| 39 | #include <linux/hardirq.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 40 | |
Tejun Heo | e8c8d1b | 2013-02-27 17:05:04 -0800 | [diff] [blame] | 41 | #define MAX_IDR_SHIFT (sizeof(int) * 8 - 1) |
| 42 | #define MAX_IDR_BIT (1U << MAX_IDR_SHIFT) |
| 43 | |
| 44 | /* Leave the possibility of an incomplete final layer */ |
| 45 | #define MAX_IDR_LEVEL ((MAX_IDR_SHIFT + IDR_BITS - 1) / IDR_BITS) |
| 46 | |
| 47 | /* Number of id_layer structs to leave in free list */ |
| 48 | #define MAX_IDR_FREE (MAX_IDR_LEVEL * 2) |
| 49 | |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 50 | static struct kmem_cache *idr_layer_cache; |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 51 | static DEFINE_PER_CPU(struct idr_layer *, idr_preload_head); |
| 52 | static DEFINE_PER_CPU(int, idr_preload_cnt); |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 53 | static DEFINE_SPINLOCK(simple_ida_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 54 | |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 55 | /* the maximum ID which can be allocated given idr->layers */ |
| 56 | static int idr_max(int layers) |
| 57 | { |
| 58 | int bits = min_t(int, layers * IDR_BITS, MAX_IDR_SHIFT); |
| 59 | |
| 60 | return (1 << bits) - 1; |
| 61 | } |
| 62 | |
Tejun Heo | 5461628 | 2013-02-27 17:05:07 -0800 | [diff] [blame] | 63 | /* |
| 64 | * Prefix mask for an idr_layer at @layer. For layer 0, the prefix mask is |
| 65 | * all bits except for the lower IDR_BITS. For layer 1, 2 * IDR_BITS, and |
| 66 | * so on. |
| 67 | */ |
| 68 | static int idr_layer_prefix_mask(int layer) |
| 69 | { |
| 70 | return ~idr_max(layer + 1); |
| 71 | } |
| 72 | |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 73 | static struct idr_layer *get_from_free_list(struct idr *idp) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | { |
| 75 | struct idr_layer *p; |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 76 | unsigned long flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 77 | |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 78 | spin_lock_irqsave(&idp->lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 79 | if ((p = idp->id_free)) { |
| 80 | idp->id_free = p->ary[0]; |
| 81 | idp->id_free_cnt--; |
| 82 | p->ary[0] = NULL; |
| 83 | } |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 84 | spin_unlock_irqrestore(&idp->lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 85 | return(p); |
| 86 | } |
| 87 | |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 88 | /** |
| 89 | * idr_layer_alloc - allocate a new idr_layer |
| 90 | * @gfp_mask: allocation mask |
| 91 | * @layer_idr: optional idr to allocate from |
| 92 | * |
| 93 | * If @layer_idr is %NULL, directly allocate one using @gfp_mask or fetch |
| 94 | * one from the per-cpu preload buffer. If @layer_idr is not %NULL, fetch |
| 95 | * an idr_layer from @idr->id_free. |
| 96 | * |
| 97 | * @layer_idr is to maintain backward compatibility with the old alloc |
| 98 | * interface - idr_pre_get() and idr_get_new*() - and will be removed |
| 99 | * together with per-pool preload buffer. |
| 100 | */ |
| 101 | static struct idr_layer *idr_layer_alloc(gfp_t gfp_mask, struct idr *layer_idr) |
| 102 | { |
| 103 | struct idr_layer *new; |
| 104 | |
| 105 | /* this is the old path, bypass to get_from_free_list() */ |
| 106 | if (layer_idr) |
| 107 | return get_from_free_list(layer_idr); |
| 108 | |
Tejun Heo | 59bfbcf | 2013-03-13 14:59:49 -0700 | [diff] [blame] | 109 | /* |
| 110 | * Try to allocate directly from kmem_cache. We want to try this |
| 111 | * before preload buffer; otherwise, non-preloading idr_alloc() |
| 112 | * users will end up taking advantage of preloading ones. As the |
| 113 | * following is allowed to fail for preloaded cases, suppress |
| 114 | * warning this time. |
| 115 | */ |
| 116 | new = kmem_cache_zalloc(idr_layer_cache, gfp_mask | __GFP_NOWARN); |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 117 | if (new) |
| 118 | return new; |
| 119 | |
| 120 | /* |
| 121 | * Try to fetch one from the per-cpu preload buffer if in process |
| 122 | * context. See idr_preload() for details. |
| 123 | */ |
Tejun Heo | 59bfbcf | 2013-03-13 14:59:49 -0700 | [diff] [blame] | 124 | if (!in_interrupt()) { |
| 125 | preempt_disable(); |
| 126 | new = __this_cpu_read(idr_preload_head); |
| 127 | if (new) { |
| 128 | __this_cpu_write(idr_preload_head, new->ary[0]); |
| 129 | __this_cpu_dec(idr_preload_cnt); |
| 130 | new->ary[0] = NULL; |
| 131 | } |
| 132 | preempt_enable(); |
| 133 | if (new) |
| 134 | return new; |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 135 | } |
Tejun Heo | 59bfbcf | 2013-03-13 14:59:49 -0700 | [diff] [blame] | 136 | |
| 137 | /* |
| 138 | * Both failed. Try kmem_cache again w/o adding __GFP_NOWARN so |
| 139 | * that memory allocation failure warning is printed as intended. |
| 140 | */ |
| 141 | return kmem_cache_zalloc(idr_layer_cache, gfp_mask); |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 142 | } |
| 143 | |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 144 | static void idr_layer_rcu_free(struct rcu_head *head) |
| 145 | { |
| 146 | struct idr_layer *layer; |
| 147 | |
| 148 | layer = container_of(head, struct idr_layer, rcu_head); |
| 149 | kmem_cache_free(idr_layer_cache, layer); |
| 150 | } |
| 151 | |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 152 | static inline void free_layer(struct idr *idr, struct idr_layer *p) |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 153 | { |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 154 | if (idr->hint && idr->hint == p) |
| 155 | RCU_INIT_POINTER(idr->hint, NULL); |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 156 | call_rcu(&p->rcu_head, idr_layer_rcu_free); |
| 157 | } |
| 158 | |
Sonny Rao | 1eec005 | 2006-06-25 05:49:34 -0700 | [diff] [blame] | 159 | /* only called when idp->lock is held */ |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 160 | 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] | 161 | { |
| 162 | p->ary[0] = idp->id_free; |
| 163 | idp->id_free = p; |
| 164 | idp->id_free_cnt++; |
| 165 | } |
| 166 | |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 167 | 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] | 168 | { |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 169 | unsigned long flags; |
| 170 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 171 | /* |
| 172 | * Depends on the return element being zeroed. |
| 173 | */ |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 174 | spin_lock_irqsave(&idp->lock, flags); |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 175 | __move_to_free_list(idp, p); |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 176 | spin_unlock_irqrestore(&idp->lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 177 | } |
| 178 | |
Tejun Heo | e33ac8b | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 179 | static void idr_mark_full(struct idr_layer **pa, int id) |
| 180 | { |
| 181 | struct idr_layer *p = pa[0]; |
| 182 | int l = 0; |
| 183 | |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 184 | __set_bit(id & IDR_MASK, p->bitmap); |
Tejun Heo | e33ac8b | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 185 | /* |
| 186 | * If this layer is full mark the bit in the layer above to |
| 187 | * show that this part of the radix tree is full. This may |
| 188 | * complete the layer above and require walking up the radix |
| 189 | * tree. |
| 190 | */ |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 191 | while (bitmap_full(p->bitmap, IDR_SIZE)) { |
Tejun Heo | e33ac8b | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 192 | if (!(p = pa[++l])) |
| 193 | break; |
| 194 | id = id >> IDR_BITS; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 195 | __set_bit((id & IDR_MASK), p->bitmap); |
Tejun Heo | e33ac8b | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 196 | } |
| 197 | } |
| 198 | |
Tejun Heo | c8615d3 | 2013-03-13 14:59:42 -0700 | [diff] [blame] | 199 | int __idr_pre_get(struct idr *idp, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 200 | { |
Fengguang Wu | 125c4c7 | 2012-10-04 17:13:15 -0700 | [diff] [blame] | 201 | while (idp->id_free_cnt < MAX_IDR_FREE) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 202 | struct idr_layer *new; |
Andrew Morton | 5b019e9 | 2009-01-15 13:51:21 -0800 | [diff] [blame] | 203 | new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 204 | if (new == NULL) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 205 | return (0); |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 206 | move_to_free_list(idp, new); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 207 | } |
| 208 | return 1; |
| 209 | } |
Tejun Heo | c8615d3 | 2013-03-13 14:59:42 -0700 | [diff] [blame] | 210 | EXPORT_SYMBOL(__idr_pre_get); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 211 | |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 212 | /** |
| 213 | * sub_alloc - try to allocate an id without growing the tree depth |
| 214 | * @idp: idr handle |
| 215 | * @starting_id: id to start search at |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 216 | * @pa: idr_layer[MAX_IDR_LEVEL] used as backtrack buffer |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 217 | * @gfp_mask: allocation mask for idr_layer_alloc() |
| 218 | * @layer_idr: optional idr passed to idr_layer_alloc() |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 219 | * |
| 220 | * Allocate an id in range [@starting_id, INT_MAX] from @idp without |
| 221 | * growing its depth. Returns |
| 222 | * |
| 223 | * the allocated id >= 0 if successful, |
| 224 | * -EAGAIN if the tree needs to grow for allocation to succeed, |
| 225 | * -ENOSPC if the id space is exhausted, |
| 226 | * -ENOMEM if more idr_layers need to be allocated. |
| 227 | */ |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 228 | static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa, |
| 229 | gfp_t gfp_mask, struct idr *layer_idr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 230 | { |
| 231 | int n, m, sh; |
| 232 | struct idr_layer *p, *new; |
Tejun Heo | 7aae6dd | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 233 | int l, id, oid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 234 | |
| 235 | id = *starting_id; |
Tejun Heo | 7aae6dd | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 236 | restart: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 237 | p = idp->top; |
| 238 | l = idp->layers; |
| 239 | pa[l--] = NULL; |
| 240 | while (1) { |
| 241 | /* |
| 242 | * We run around this while until we reach the leaf node... |
| 243 | */ |
| 244 | n = (id >> (IDR_BITS*l)) & IDR_MASK; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 245 | m = find_next_zero_bit(p->bitmap, IDR_SIZE, n); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 246 | if (m == IDR_SIZE) { |
| 247 | /* no space available go back to previous layer. */ |
| 248 | l++; |
Tejun Heo | 7aae6dd | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 249 | oid = id; |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 250 | id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1; |
Tejun Heo | 7aae6dd | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 251 | |
| 252 | /* if already at the top layer, we need to grow */ |
Tejun Heo | d2e7276 | 2010-02-22 12:44:19 -0800 | [diff] [blame] | 253 | if (id >= 1 << (idp->layers * IDR_BITS)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 254 | *starting_id = id; |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 255 | return -EAGAIN; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 256 | } |
Tejun Heo | d2e7276 | 2010-02-22 12:44:19 -0800 | [diff] [blame] | 257 | p = pa[l]; |
| 258 | BUG_ON(!p); |
Tejun Heo | 7aae6dd | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 259 | |
| 260 | /* If we need to go up one layer, continue the |
| 261 | * loop; otherwise, restart from the top. |
| 262 | */ |
| 263 | sh = IDR_BITS * (l + 1); |
| 264 | if (oid >> sh == id >> sh) |
| 265 | continue; |
| 266 | else |
| 267 | goto restart; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 268 | } |
| 269 | if (m != n) { |
| 270 | sh = IDR_BITS*l; |
| 271 | id = ((id >> sh) ^ n ^ m) << sh; |
| 272 | } |
Fengguang Wu | 125c4c7 | 2012-10-04 17:13:15 -0700 | [diff] [blame] | 273 | if ((id >= MAX_IDR_BIT) || (id < 0)) |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 274 | return -ENOSPC; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 275 | if (l == 0) |
| 276 | break; |
| 277 | /* |
| 278 | * Create the layer below if it is missing. |
| 279 | */ |
| 280 | if (!p->ary[m]) { |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 281 | new = idr_layer_alloc(gfp_mask, layer_idr); |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 282 | if (!new) |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 283 | return -ENOMEM; |
Manfred Spraul | 6ff2d39 | 2008-12-01 13:14:02 -0800 | [diff] [blame] | 284 | new->layer = l-1; |
Tejun Heo | 5461628 | 2013-02-27 17:05:07 -0800 | [diff] [blame] | 285 | new->prefix = id & idr_layer_prefix_mask(new->layer); |
Nadia Derbey | 3219b3b | 2008-07-25 01:48:00 -0700 | [diff] [blame] | 286 | rcu_assign_pointer(p->ary[m], new); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 287 | p->count++; |
| 288 | } |
| 289 | pa[l--] = p; |
| 290 | p = p->ary[m]; |
| 291 | } |
Tejun Heo | e33ac8b | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 292 | |
| 293 | pa[l] = p; |
| 294 | return id; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 295 | } |
| 296 | |
Tejun Heo | e33ac8b | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 297 | static int idr_get_empty_slot(struct idr *idp, int starting_id, |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 298 | struct idr_layer **pa, gfp_t gfp_mask, |
| 299 | struct idr *layer_idr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 300 | { |
| 301 | struct idr_layer *p, *new; |
| 302 | int layers, v, id; |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 303 | unsigned long flags; |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 304 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 305 | id = starting_id; |
| 306 | build_up: |
| 307 | p = idp->top; |
| 308 | layers = idp->layers; |
| 309 | if (unlikely(!p)) { |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 310 | if (!(p = idr_layer_alloc(gfp_mask, layer_idr))) |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 311 | return -ENOMEM; |
Manfred Spraul | 6ff2d39 | 2008-12-01 13:14:02 -0800 | [diff] [blame] | 312 | p->layer = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 313 | layers = 1; |
| 314 | } |
| 315 | /* |
| 316 | * Add a new layer to the top of the tree if the requested |
| 317 | * id is larger than the currently allocated space. |
| 318 | */ |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 319 | while (id > idr_max(layers)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 320 | layers++; |
Manfred Spraul | 711a49a | 2008-12-10 18:17:06 +0100 | [diff] [blame] | 321 | if (!p->count) { |
| 322 | /* special case: if the tree is currently empty, |
| 323 | * then we grow the tree by moving the top node |
| 324 | * upwards. |
| 325 | */ |
| 326 | p->layer++; |
Tejun Heo | 5461628 | 2013-02-27 17:05:07 -0800 | [diff] [blame] | 327 | WARN_ON_ONCE(p->prefix); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 328 | continue; |
Manfred Spraul | 711a49a | 2008-12-10 18:17:06 +0100 | [diff] [blame] | 329 | } |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 330 | if (!(new = idr_layer_alloc(gfp_mask, layer_idr))) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 331 | /* |
| 332 | * The allocation failed. If we built part of |
| 333 | * the structure tear it down. |
| 334 | */ |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 335 | spin_lock_irqsave(&idp->lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 336 | for (new = p; p && p != idp->top; new = p) { |
| 337 | p = p->ary[0]; |
| 338 | new->ary[0] = NULL; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 339 | new->count = 0; |
| 340 | bitmap_clear(new->bitmap, 0, IDR_SIZE); |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 341 | __move_to_free_list(idp, new); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 342 | } |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 343 | spin_unlock_irqrestore(&idp->lock, flags); |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 344 | return -ENOMEM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 345 | } |
| 346 | new->ary[0] = p; |
| 347 | new->count = 1; |
Manfred Spraul | 6ff2d39 | 2008-12-01 13:14:02 -0800 | [diff] [blame] | 348 | new->layer = layers-1; |
Tejun Heo | 5461628 | 2013-02-27 17:05:07 -0800 | [diff] [blame] | 349 | new->prefix = id & idr_layer_prefix_mask(new->layer); |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 350 | if (bitmap_full(p->bitmap, IDR_SIZE)) |
| 351 | __set_bit(0, new->bitmap); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 352 | p = new; |
| 353 | } |
Nadia Derbey | 3219b3b | 2008-07-25 01:48:00 -0700 | [diff] [blame] | 354 | rcu_assign_pointer(idp->top, p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 355 | idp->layers = layers; |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 356 | v = sub_alloc(idp, &id, pa, gfp_mask, layer_idr); |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 357 | if (v == -EAGAIN) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 358 | goto build_up; |
| 359 | return(v); |
| 360 | } |
| 361 | |
Tejun Heo | 3594eb2 | 2013-02-27 17:03:54 -0800 | [diff] [blame] | 362 | /* |
| 363 | * @id and @pa are from a successful allocation from idr_get_empty_slot(). |
| 364 | * Install the user pointer @ptr and mark the slot full. |
| 365 | */ |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 366 | static void idr_fill_slot(struct idr *idr, void *ptr, int id, |
| 367 | struct idr_layer **pa) |
Tejun Heo | e33ac8b | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 368 | { |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 369 | /* update hint used for lookup, cleared from free_layer() */ |
| 370 | rcu_assign_pointer(idr->hint, pa[0]); |
| 371 | |
Tejun Heo | 3594eb2 | 2013-02-27 17:03:54 -0800 | [diff] [blame] | 372 | rcu_assign_pointer(pa[0]->ary[id & IDR_MASK], (struct idr_layer *)ptr); |
| 373 | pa[0]->count++; |
| 374 | idr_mark_full(pa, id); |
Tejun Heo | e33ac8b | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 375 | } |
| 376 | |
Tejun Heo | c8615d3 | 2013-03-13 14:59:42 -0700 | [diff] [blame] | 377 | int __idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 378 | { |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 379 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 380 | int rv; |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 381 | |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 382 | rv = idr_get_empty_slot(idp, starting_id, pa, 0, idp); |
Nadia Derbey | 944ca05 | 2008-07-25 01:47:59 -0700 | [diff] [blame] | 383 | if (rv < 0) |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 384 | return rv == -ENOMEM ? -EAGAIN : rv; |
Tejun Heo | 3594eb2 | 2013-02-27 17:03:54 -0800 | [diff] [blame] | 385 | |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 386 | idr_fill_slot(idp, ptr, rv, pa); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 387 | *id = rv; |
| 388 | return 0; |
| 389 | } |
Tejun Heo | c8615d3 | 2013-03-13 14:59:42 -0700 | [diff] [blame] | 390 | EXPORT_SYMBOL(__idr_get_new_above); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 391 | |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 392 | /** |
| 393 | * idr_preload - preload for idr_alloc() |
| 394 | * @gfp_mask: allocation mask to use for preloading |
| 395 | * |
| 396 | * Preload per-cpu layer buffer for idr_alloc(). Can only be used from |
| 397 | * process context and each idr_preload() invocation should be matched with |
| 398 | * idr_preload_end(). Note that preemption is disabled while preloaded. |
| 399 | * |
| 400 | * The first idr_alloc() in the preloaded section can be treated as if it |
| 401 | * were invoked with @gfp_mask used for preloading. This allows using more |
| 402 | * permissive allocation masks for idrs protected by spinlocks. |
| 403 | * |
| 404 | * For example, if idr_alloc() below fails, the failure can be treated as |
| 405 | * if idr_alloc() were called with GFP_KERNEL rather than GFP_NOWAIT. |
| 406 | * |
| 407 | * idr_preload(GFP_KERNEL); |
| 408 | * spin_lock(lock); |
| 409 | * |
| 410 | * id = idr_alloc(idr, ptr, start, end, GFP_NOWAIT); |
| 411 | * |
| 412 | * spin_unlock(lock); |
| 413 | * idr_preload_end(); |
| 414 | * if (id < 0) |
| 415 | * error; |
| 416 | */ |
| 417 | void idr_preload(gfp_t gfp_mask) |
| 418 | { |
| 419 | /* |
| 420 | * Consuming preload buffer from non-process context breaks preload |
| 421 | * allocation guarantee. Disallow usage from those contexts. |
| 422 | */ |
| 423 | WARN_ON_ONCE(in_interrupt()); |
| 424 | might_sleep_if(gfp_mask & __GFP_WAIT); |
| 425 | |
| 426 | preempt_disable(); |
| 427 | |
| 428 | /* |
| 429 | * idr_alloc() is likely to succeed w/o full idr_layer buffer and |
| 430 | * return value from idr_alloc() needs to be checked for failure |
| 431 | * anyway. Silently give up if allocation fails. The caller can |
| 432 | * treat failures from idr_alloc() as if idr_alloc() were called |
| 433 | * with @gfp_mask which should be enough. |
| 434 | */ |
| 435 | while (__this_cpu_read(idr_preload_cnt) < MAX_IDR_FREE) { |
| 436 | struct idr_layer *new; |
| 437 | |
| 438 | preempt_enable(); |
| 439 | new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); |
| 440 | preempt_disable(); |
| 441 | if (!new) |
| 442 | break; |
| 443 | |
| 444 | /* link the new one to per-cpu preload list */ |
| 445 | new->ary[0] = __this_cpu_read(idr_preload_head); |
| 446 | __this_cpu_write(idr_preload_head, new); |
| 447 | __this_cpu_inc(idr_preload_cnt); |
| 448 | } |
| 449 | } |
| 450 | EXPORT_SYMBOL(idr_preload); |
| 451 | |
| 452 | /** |
| 453 | * idr_alloc - allocate new idr entry |
| 454 | * @idr: the (initialized) idr |
| 455 | * @ptr: pointer to be associated with the new id |
| 456 | * @start: the minimum id (inclusive) |
| 457 | * @end: the maximum id (exclusive, <= 0 for max) |
| 458 | * @gfp_mask: memory allocation flags |
| 459 | * |
| 460 | * Allocate an id in [start, end) and associate it with @ptr. If no ID is |
| 461 | * available in the specified range, returns -ENOSPC. On memory allocation |
| 462 | * failure, returns -ENOMEM. |
| 463 | * |
| 464 | * Note that @end is treated as max when <= 0. This is to always allow |
| 465 | * using @start + N as @end as long as N is inside integer range. |
| 466 | * |
| 467 | * The user is responsible for exclusively synchronizing all operations |
| 468 | * which may modify @idr. However, read-only accesses such as idr_find() |
| 469 | * or iteration can be performed under RCU read lock provided the user |
| 470 | * destroys @ptr in RCU-safe way after removal from idr. |
| 471 | */ |
| 472 | int idr_alloc(struct idr *idr, void *ptr, int start, int end, gfp_t gfp_mask) |
| 473 | { |
| 474 | int max = end > 0 ? end - 1 : INT_MAX; /* inclusive upper limit */ |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 475 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 476 | int id; |
| 477 | |
| 478 | might_sleep_if(gfp_mask & __GFP_WAIT); |
| 479 | |
| 480 | /* sanity checks */ |
| 481 | if (WARN_ON_ONCE(start < 0)) |
| 482 | return -EINVAL; |
| 483 | if (unlikely(max < start)) |
| 484 | return -ENOSPC; |
| 485 | |
| 486 | /* allocate id */ |
| 487 | id = idr_get_empty_slot(idr, start, pa, gfp_mask, NULL); |
| 488 | if (unlikely(id < 0)) |
| 489 | return id; |
| 490 | if (unlikely(id > max)) |
| 491 | return -ENOSPC; |
| 492 | |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 493 | idr_fill_slot(idr, ptr, id, pa); |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 494 | return id; |
| 495 | } |
| 496 | EXPORT_SYMBOL_GPL(idr_alloc); |
| 497 | |
Jeff Layton | 3e6628c4 | 2013-04-29 16:21:16 -0700 | [diff] [blame] | 498 | /** |
| 499 | * idr_alloc_cyclic - allocate new idr entry in a cyclical fashion |
| 500 | * @idr: the (initialized) idr |
| 501 | * @ptr: pointer to be associated with the new id |
| 502 | * @start: the minimum id (inclusive) |
| 503 | * @end: the maximum id (exclusive, <= 0 for max) |
| 504 | * @gfp_mask: memory allocation flags |
| 505 | * |
| 506 | * Essentially the same as idr_alloc, but prefers to allocate progressively |
| 507 | * higher ids if it can. If the "cur" counter wraps, then it will start again |
| 508 | * at the "start" end of the range and allocate one that has already been used. |
| 509 | */ |
| 510 | int idr_alloc_cyclic(struct idr *idr, void *ptr, int start, int end, |
| 511 | gfp_t gfp_mask) |
| 512 | { |
| 513 | int id; |
| 514 | |
| 515 | id = idr_alloc(idr, ptr, max(start, idr->cur), end, gfp_mask); |
| 516 | if (id == -ENOSPC) |
| 517 | id = idr_alloc(idr, ptr, start, end, gfp_mask); |
| 518 | |
| 519 | if (likely(id >= 0)) |
| 520 | idr->cur = id + 1; |
| 521 | return id; |
| 522 | } |
| 523 | EXPORT_SYMBOL(idr_alloc_cyclic); |
| 524 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 525 | static void idr_remove_warning(int id) |
| 526 | { |
Jean Delvare | dd04b45 | 2013-07-03 15:08:47 -0700 | [diff] [blame] | 527 | 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] | 528 | } |
| 529 | |
| 530 | static void sub_remove(struct idr *idp, int shift, int id) |
| 531 | { |
| 532 | struct idr_layer *p = idp->top; |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 533 | struct idr_layer **pa[MAX_IDR_LEVEL + 1]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 534 | struct idr_layer ***paa = &pa[0]; |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 535 | struct idr_layer *to_free; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 536 | int n; |
| 537 | |
| 538 | *paa = NULL; |
| 539 | *++paa = &idp->top; |
| 540 | |
| 541 | while ((shift > 0) && p) { |
| 542 | n = (id >> shift) & IDR_MASK; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 543 | __clear_bit(n, p->bitmap); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 544 | *++paa = &p->ary[n]; |
| 545 | p = p->ary[n]; |
| 546 | shift -= IDR_BITS; |
| 547 | } |
| 548 | n = id & IDR_MASK; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 549 | if (likely(p != NULL && test_bit(n, p->bitmap))) { |
| 550 | __clear_bit(n, p->bitmap); |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 551 | rcu_assign_pointer(p->ary[n], NULL); |
| 552 | to_free = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 553 | while(*paa && ! --((**paa)->count)){ |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 554 | if (to_free) |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 555 | free_layer(idp, to_free); |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 556 | to_free = **paa; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 557 | **paa-- = NULL; |
| 558 | } |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 559 | if (!*paa) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 560 | idp->layers = 0; |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 561 | if (to_free) |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 562 | free_layer(idp, to_free); |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 563 | } else |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 564 | idr_remove_warning(id); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 565 | } |
| 566 | |
| 567 | /** |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 568 | * idr_remove - remove the given id and free its slot |
Robert P. J. Day | 72fd4a3 | 2007-02-10 01:45:59 -0800 | [diff] [blame] | 569 | * @idp: idr handle |
| 570 | * @id: unique key |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 571 | */ |
| 572 | void idr_remove(struct idr *idp, int id) |
| 573 | { |
| 574 | struct idr_layer *p; |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 575 | struct idr_layer *to_free; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 576 | |
Tejun Heo | 2e1c9b2 | 2013-03-08 12:43:30 -0800 | [diff] [blame] | 577 | if (id < 0) |
Tejun Heo | e8c8d1b | 2013-02-27 17:05:04 -0800 | [diff] [blame] | 578 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 579 | |
| 580 | sub_remove(idp, (idp->layers - 1) * IDR_BITS, id); |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 581 | if (idp->top && idp->top->count == 1 && (idp->layers > 1) && |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 582 | idp->top->ary[0]) { |
| 583 | /* |
| 584 | * Single child at leftmost slot: we can shrink the tree. |
| 585 | * This level is not needed anymore since when layers are |
| 586 | * inserted, they are inserted at the top of the existing |
| 587 | * tree. |
| 588 | */ |
| 589 | to_free = idp->top; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 590 | p = idp->top->ary[0]; |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 591 | rcu_assign_pointer(idp->top, p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 592 | --idp->layers; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 593 | to_free->count = 0; |
| 594 | bitmap_clear(to_free->bitmap, 0, IDR_SIZE); |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 595 | free_layer(idp, to_free); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 596 | } |
Fengguang Wu | 125c4c7 | 2012-10-04 17:13:15 -0700 | [diff] [blame] | 597 | while (idp->id_free_cnt >= MAX_IDR_FREE) { |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 598 | p = get_from_free_list(idp); |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 599 | /* |
| 600 | * Note: we don't call the rcu callback here, since the only |
| 601 | * layers that fall into the freelist are those that have been |
| 602 | * preallocated. |
| 603 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 604 | kmem_cache_free(idr_layer_cache, p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 605 | } |
Nadia Derbey | af8e2a4 | 2008-05-01 04:34:57 -0700 | [diff] [blame] | 606 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 607 | } |
| 608 | EXPORT_SYMBOL(idr_remove); |
| 609 | |
Tejun Heo | fe6e24e | 2013-02-27 17:03:50 -0800 | [diff] [blame] | 610 | void __idr_remove_all(struct idr *idp) |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 611 | { |
Oleg Nesterov | 6ace06dc | 2007-07-31 00:39:19 -0700 | [diff] [blame] | 612 | int n, id, max; |
Imre Deak | 2dcb22b | 2010-05-26 14:43:38 -0700 | [diff] [blame] | 613 | int bt_mask; |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 614 | struct idr_layer *p; |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 615 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 616 | struct idr_layer **paa = &pa[0]; |
| 617 | |
| 618 | n = idp->layers * IDR_BITS; |
| 619 | p = idp->top; |
Paul E. McKenney | 1b23336 | 2009-03-10 12:55:52 -0700 | [diff] [blame] | 620 | rcu_assign_pointer(idp->top, NULL); |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 621 | max = idr_max(idp->layers); |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 622 | |
| 623 | id = 0; |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 624 | while (id >= 0 && id <= max) { |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 625 | while (n > IDR_BITS && p) { |
| 626 | n -= IDR_BITS; |
| 627 | *paa++ = p; |
| 628 | p = p->ary[(id >> n) & IDR_MASK]; |
| 629 | } |
| 630 | |
Imre Deak | 2dcb22b | 2010-05-26 14:43:38 -0700 | [diff] [blame] | 631 | bt_mask = id; |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 632 | id += 1 << n; |
Imre Deak | 2dcb22b | 2010-05-26 14:43:38 -0700 | [diff] [blame] | 633 | /* Get the highest bit that the above add changed from 0->1. */ |
| 634 | while (n < fls(id ^ bt_mask)) { |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 635 | if (p) |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 636 | free_layer(idp, p); |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 637 | n += IDR_BITS; |
| 638 | p = *--paa; |
| 639 | } |
| 640 | } |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 641 | idp->layers = 0; |
| 642 | } |
Tejun Heo | fe6e24e | 2013-02-27 17:03:50 -0800 | [diff] [blame] | 643 | EXPORT_SYMBOL(__idr_remove_all); |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 644 | |
| 645 | /** |
Andrew Morton | 8d3b359 | 2005-10-23 12:57:18 -0700 | [diff] [blame] | 646 | * idr_destroy - release all cached layers within an idr tree |
Naohiro Aota | ea24ea8 | 2010-08-31 00:37:03 +0900 | [diff] [blame] | 647 | * @idp: idr handle |
Tejun Heo | 9bb26bc | 2013-02-27 17:03:35 -0800 | [diff] [blame] | 648 | * |
| 649 | * Free all id mappings and all idp_layers. After this function, @idp is |
| 650 | * completely unused and can be freed / recycled. The caller is |
| 651 | * responsible for ensuring that no one else accesses @idp during or after |
| 652 | * idr_destroy(). |
| 653 | * |
| 654 | * A typical clean-up sequence for objects stored in an idr tree will use |
| 655 | * idr_for_each() to free all objects, if necessay, then idr_destroy() to |
| 656 | * free up the id mappings and cached idr_layers. |
Andrew Morton | 8d3b359 | 2005-10-23 12:57:18 -0700 | [diff] [blame] | 657 | */ |
| 658 | void idr_destroy(struct idr *idp) |
| 659 | { |
Tejun Heo | fe6e24e | 2013-02-27 17:03:50 -0800 | [diff] [blame] | 660 | __idr_remove_all(idp); |
Tejun Heo | 9bb26bc | 2013-02-27 17:03:35 -0800 | [diff] [blame] | 661 | |
Andrew Morton | 8d3b359 | 2005-10-23 12:57:18 -0700 | [diff] [blame] | 662 | while (idp->id_free_cnt) { |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 663 | struct idr_layer *p = get_from_free_list(idp); |
Andrew Morton | 8d3b359 | 2005-10-23 12:57:18 -0700 | [diff] [blame] | 664 | kmem_cache_free(idr_layer_cache, p); |
| 665 | } |
| 666 | } |
| 667 | EXPORT_SYMBOL(idr_destroy); |
| 668 | |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 669 | void *idr_find_slowpath(struct idr *idp, int id) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 670 | { |
| 671 | int n; |
| 672 | struct idr_layer *p; |
| 673 | |
Tejun Heo | 2e1c9b2 | 2013-03-08 12:43:30 -0800 | [diff] [blame] | 674 | if (id < 0) |
Tejun Heo | e8c8d1b | 2013-02-27 17:05:04 -0800 | [diff] [blame] | 675 | return NULL; |
| 676 | |
Paul E. McKenney | 96be753 | 2010-02-22 17:04:55 -0800 | [diff] [blame] | 677 | p = rcu_dereference_raw(idp->top); |
Manfred Spraul | 6ff2d39 | 2008-12-01 13:14:02 -0800 | [diff] [blame] | 678 | if (!p) |
| 679 | return NULL; |
| 680 | n = (p->layer+1) * IDR_BITS; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 681 | |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 682 | if (id > idr_max(p->layer + 1)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 683 | return NULL; |
Manfred Spraul | 6ff2d39 | 2008-12-01 13:14:02 -0800 | [diff] [blame] | 684 | BUG_ON(n == 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 685 | |
| 686 | while (n > 0 && p) { |
| 687 | n -= IDR_BITS; |
Manfred Spraul | 6ff2d39 | 2008-12-01 13:14:02 -0800 | [diff] [blame] | 688 | BUG_ON(n != p->layer*IDR_BITS); |
Paul E. McKenney | 96be753 | 2010-02-22 17:04:55 -0800 | [diff] [blame] | 689 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 690 | } |
| 691 | return((void *)p); |
| 692 | } |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 693 | EXPORT_SYMBOL(idr_find_slowpath); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 694 | |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 695 | /** |
Kristian Hoegsberg | 96d7fa4 | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 696 | * idr_for_each - iterate through all stored pointers |
| 697 | * @idp: idr handle |
| 698 | * @fn: function to be called for each pointer |
| 699 | * @data: data passed back to callback function |
| 700 | * |
| 701 | * Iterate over the pointers registered with the given idr. The |
| 702 | * callback function will be called for each pointer currently |
| 703 | * registered, passing the id, the pointer and the data pointer passed |
| 704 | * to this function. It is not safe to modify the idr tree while in |
| 705 | * the callback, so functions such as idr_get_new and idr_remove are |
| 706 | * not allowed. |
| 707 | * |
| 708 | * 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] | 709 | * than %0, we break out and return that value. |
Kristian Hoegsberg | 96d7fa4 | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 710 | * |
| 711 | * The caller must serialize idr_for_each() vs idr_get_new() and idr_remove(). |
| 712 | */ |
| 713 | int idr_for_each(struct idr *idp, |
| 714 | int (*fn)(int id, void *p, void *data), void *data) |
| 715 | { |
| 716 | int n, id, max, error = 0; |
| 717 | struct idr_layer *p; |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 718 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
Kristian Hoegsberg | 96d7fa4 | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 719 | struct idr_layer **paa = &pa[0]; |
| 720 | |
| 721 | n = idp->layers * IDR_BITS; |
Paul E. McKenney | 96be753 | 2010-02-22 17:04:55 -0800 | [diff] [blame] | 722 | p = rcu_dereference_raw(idp->top); |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 723 | max = idr_max(idp->layers); |
Kristian Hoegsberg | 96d7fa4 | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 724 | |
| 725 | id = 0; |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 726 | while (id >= 0 && id <= max) { |
Kristian Hoegsberg | 96d7fa4 | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 727 | while (n > 0 && p) { |
| 728 | n -= IDR_BITS; |
| 729 | *paa++ = p; |
Paul E. McKenney | 96be753 | 2010-02-22 17:04:55 -0800 | [diff] [blame] | 730 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
Kristian Hoegsberg | 96d7fa4 | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 731 | } |
| 732 | |
| 733 | if (p) { |
| 734 | error = fn(id, (void *)p, data); |
| 735 | if (error) |
| 736 | break; |
| 737 | } |
| 738 | |
| 739 | id += 1 << n; |
| 740 | while (n < fls(id)) { |
| 741 | n += IDR_BITS; |
| 742 | p = *--paa; |
| 743 | } |
| 744 | } |
| 745 | |
| 746 | return error; |
| 747 | } |
| 748 | EXPORT_SYMBOL(idr_for_each); |
| 749 | |
| 750 | /** |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 751 | * idr_get_next - lookup next object of id to given id. |
| 752 | * @idp: idr handle |
Naohiro Aota | ea24ea8 | 2010-08-31 00:37:03 +0900 | [diff] [blame] | 753 | * @nextidp: pointer to lookup key |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 754 | * |
| 755 | * Returns pointer to registered object with id, which is next number to |
Naohiro Aota | 1458ce1 | 2010-08-27 17:43:46 +0900 | [diff] [blame] | 756 | * given id. After being looked up, *@nextidp will be updated for the next |
| 757 | * iteration. |
Hugh Dickins | 9f7de82 | 2012-03-21 16:34:20 -0700 | [diff] [blame] | 758 | * |
| 759 | * This function can be called under rcu_read_lock(), given that the leaf |
| 760 | * pointers lifetimes are correctly managed. |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 761 | */ |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 762 | void *idr_get_next(struct idr *idp, int *nextidp) |
| 763 | { |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 764 | struct idr_layer *p, *pa[MAX_IDR_LEVEL + 1]; |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 765 | struct idr_layer **paa = &pa[0]; |
| 766 | int id = *nextidp; |
| 767 | int n, max; |
| 768 | |
| 769 | /* find first ent */ |
Paul E. McKenney | 94bfa3b | 2010-06-07 17:09:45 -0700 | [diff] [blame] | 770 | p = rcu_dereference_raw(idp->top); |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 771 | if (!p) |
| 772 | return NULL; |
Hugh Dickins | 9f7de82 | 2012-03-21 16:34:20 -0700 | [diff] [blame] | 773 | n = (p->layer + 1) * IDR_BITS; |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 774 | max = idr_max(p->layer + 1); |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 775 | |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 776 | while (id >= 0 && id <= max) { |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 777 | while (n > 0 && p) { |
| 778 | n -= IDR_BITS; |
| 779 | *paa++ = p; |
Paul E. McKenney | 94bfa3b | 2010-06-07 17:09:45 -0700 | [diff] [blame] | 780 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 781 | } |
| 782 | |
| 783 | if (p) { |
| 784 | *nextidp = id; |
| 785 | return p; |
| 786 | } |
| 787 | |
Tejun Heo | 6cdae74 | 2013-02-27 17:03:34 -0800 | [diff] [blame] | 788 | /* |
| 789 | * Proceed to the next layer at the current level. Unlike |
| 790 | * idr_for_each(), @id isn't guaranteed to be aligned to |
| 791 | * layer boundary at this point and adding 1 << n may |
| 792 | * incorrectly skip IDs. Make sure we jump to the |
| 793 | * beginning of the next layer using round_up(). |
| 794 | */ |
| 795 | id = round_up(id + 1, 1 << n); |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 796 | while (n < fls(id)) { |
| 797 | n += IDR_BITS; |
| 798 | p = *--paa; |
| 799 | } |
| 800 | } |
| 801 | return NULL; |
| 802 | } |
Ben Hutchings | 4d1ee80 | 2010-01-29 20:59:17 +0000 | [diff] [blame] | 803 | EXPORT_SYMBOL(idr_get_next); |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 804 | |
| 805 | |
| 806 | /** |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 807 | * idr_replace - replace pointer for given id |
| 808 | * @idp: idr handle |
| 809 | * @ptr: pointer you want associated with the id |
| 810 | * @id: lookup key |
| 811 | * |
| 812 | * Replace the pointer registered with an id and return the old value. |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 813 | * A %-ENOENT return indicates that @id was not found. |
| 814 | * A %-EINVAL return indicates that @id was not within valid constraints. |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 815 | * |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 816 | * The caller must serialize with writers. |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 817 | */ |
| 818 | void *idr_replace(struct idr *idp, void *ptr, int id) |
| 819 | { |
| 820 | int n; |
| 821 | struct idr_layer *p, *old_p; |
| 822 | |
Tejun Heo | 2e1c9b2 | 2013-03-08 12:43:30 -0800 | [diff] [blame] | 823 | if (id < 0) |
Tejun Heo | e8c8d1b | 2013-02-27 17:05:04 -0800 | [diff] [blame] | 824 | return ERR_PTR(-EINVAL); |
| 825 | |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 826 | p = idp->top; |
Manfred Spraul | 6ff2d39 | 2008-12-01 13:14:02 -0800 | [diff] [blame] | 827 | if (!p) |
| 828 | return ERR_PTR(-EINVAL); |
| 829 | |
| 830 | n = (p->layer+1) * IDR_BITS; |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 831 | |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 832 | if (id >= (1 << n)) |
| 833 | return ERR_PTR(-EINVAL); |
| 834 | |
| 835 | n -= IDR_BITS; |
| 836 | while ((n > 0) && p) { |
| 837 | p = p->ary[(id >> n) & IDR_MASK]; |
| 838 | n -= IDR_BITS; |
| 839 | } |
| 840 | |
| 841 | n = id & IDR_MASK; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 842 | if (unlikely(p == NULL || !test_bit(n, p->bitmap))) |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 843 | return ERR_PTR(-ENOENT); |
| 844 | |
| 845 | old_p = p->ary[n]; |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 846 | rcu_assign_pointer(p->ary[n], ptr); |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 847 | |
| 848 | return old_p; |
| 849 | } |
| 850 | EXPORT_SYMBOL(idr_replace); |
| 851 | |
Akinobu Mita | 199f0ca | 2008-04-29 01:03:13 -0700 | [diff] [blame] | 852 | void __init idr_init_cache(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 853 | { |
Akinobu Mita | 199f0ca | 2008-04-29 01:03:13 -0700 | [diff] [blame] | 854 | idr_layer_cache = kmem_cache_create("idr_layer_cache", |
Andrew Morton | 5b019e9 | 2009-01-15 13:51:21 -0800 | [diff] [blame] | 855 | sizeof(struct idr_layer), 0, SLAB_PANIC, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 856 | } |
| 857 | |
| 858 | /** |
| 859 | * idr_init - initialize idr handle |
| 860 | * @idp: idr handle |
| 861 | * |
| 862 | * This function is use to set up the handle (@idp) that you will pass |
| 863 | * to the rest of the functions. |
| 864 | */ |
| 865 | void idr_init(struct idr *idp) |
| 866 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 867 | memset(idp, 0, sizeof(struct idr)); |
| 868 | spin_lock_init(&idp->lock); |
| 869 | } |
| 870 | EXPORT_SYMBOL(idr_init); |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 871 | |
Andreas Gruenbacher | 05f7a7d | 2011-08-08 23:36:56 +0200 | [diff] [blame] | 872 | static int idr_has_entry(int id, void *p, void *data) |
| 873 | { |
| 874 | return 1; |
| 875 | } |
| 876 | |
| 877 | bool idr_is_empty(struct idr *idp) |
| 878 | { |
| 879 | return !idr_for_each(idp, idr_has_entry, NULL); |
| 880 | } |
| 881 | EXPORT_SYMBOL(idr_is_empty); |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 882 | |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 883 | /** |
| 884 | * DOC: IDA description |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 885 | * IDA - IDR based ID allocator |
| 886 | * |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 887 | * This is id allocator without id -> pointer translation. Memory |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 888 | * usage is much lower than full blown idr because each id only |
| 889 | * occupies a bit. ida uses a custom leaf node which contains |
| 890 | * IDA_BITMAP_BITS slots. |
| 891 | * |
| 892 | * 2007-04-25 written by Tejun Heo <htejun@gmail.com> |
| 893 | */ |
| 894 | |
| 895 | static void free_bitmap(struct ida *ida, struct ida_bitmap *bitmap) |
| 896 | { |
| 897 | unsigned long flags; |
| 898 | |
| 899 | if (!ida->free_bitmap) { |
| 900 | spin_lock_irqsave(&ida->idr.lock, flags); |
| 901 | if (!ida->free_bitmap) { |
| 902 | ida->free_bitmap = bitmap; |
| 903 | bitmap = NULL; |
| 904 | } |
| 905 | spin_unlock_irqrestore(&ida->idr.lock, flags); |
| 906 | } |
| 907 | |
| 908 | kfree(bitmap); |
| 909 | } |
| 910 | |
| 911 | /** |
| 912 | * ida_pre_get - reserve resources for ida allocation |
| 913 | * @ida: ida handle |
| 914 | * @gfp_mask: memory allocation flag |
| 915 | * |
| 916 | * This function should be called prior to locking and calling the |
| 917 | * following function. It preallocates enough memory to satisfy the |
| 918 | * worst possible allocation. |
| 919 | * |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 920 | * If the system is REALLY out of memory this function returns %0, |
| 921 | * otherwise %1. |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 922 | */ |
| 923 | int ida_pre_get(struct ida *ida, gfp_t gfp_mask) |
| 924 | { |
| 925 | /* allocate idr_layers */ |
Tejun Heo | c8615d3 | 2013-03-13 14:59:42 -0700 | [diff] [blame] | 926 | if (!__idr_pre_get(&ida->idr, gfp_mask)) |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 927 | return 0; |
| 928 | |
| 929 | /* allocate free_bitmap */ |
| 930 | if (!ida->free_bitmap) { |
| 931 | struct ida_bitmap *bitmap; |
| 932 | |
| 933 | bitmap = kmalloc(sizeof(struct ida_bitmap), gfp_mask); |
| 934 | if (!bitmap) |
| 935 | return 0; |
| 936 | |
| 937 | free_bitmap(ida, bitmap); |
| 938 | } |
| 939 | |
| 940 | return 1; |
| 941 | } |
| 942 | EXPORT_SYMBOL(ida_pre_get); |
| 943 | |
| 944 | /** |
| 945 | * ida_get_new_above - allocate new ID above or equal to a start id |
| 946 | * @ida: ida handle |
Naohiro Aota | ea24ea8 | 2010-08-31 00:37:03 +0900 | [diff] [blame] | 947 | * @starting_id: id to start search at |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 948 | * @p_id: pointer to the allocated handle |
| 949 | * |
Wang Sheng-Hui | e3816c5 | 2011-10-31 17:12:36 -0700 | [diff] [blame] | 950 | * Allocate new ID above or equal to @starting_id. It should be called |
| 951 | * with any required locks. |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 952 | * |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 953 | * If memory is required, it will return %-EAGAIN, you should unlock |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 954 | * 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] | 955 | * return %-ENOSPC. |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 956 | * |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 957 | * @p_id returns a value in the range @starting_id ... %0x7fffffff. |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 958 | */ |
| 959 | int ida_get_new_above(struct ida *ida, int starting_id, int *p_id) |
| 960 | { |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 961 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 962 | struct ida_bitmap *bitmap; |
| 963 | unsigned long flags; |
| 964 | int idr_id = starting_id / IDA_BITMAP_BITS; |
| 965 | int offset = starting_id % IDA_BITMAP_BITS; |
| 966 | int t, id; |
| 967 | |
| 968 | restart: |
| 969 | /* get vacant slot */ |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 970 | 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] | 971 | if (t < 0) |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 972 | return t == -ENOMEM ? -EAGAIN : t; |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 973 | |
Fengguang Wu | 125c4c7 | 2012-10-04 17:13:15 -0700 | [diff] [blame] | 974 | if (t * IDA_BITMAP_BITS >= MAX_IDR_BIT) |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 975 | return -ENOSPC; |
| 976 | |
| 977 | if (t != idr_id) |
| 978 | offset = 0; |
| 979 | idr_id = t; |
| 980 | |
| 981 | /* if bitmap isn't there, create a new one */ |
| 982 | bitmap = (void *)pa[0]->ary[idr_id & IDR_MASK]; |
| 983 | if (!bitmap) { |
| 984 | spin_lock_irqsave(&ida->idr.lock, flags); |
| 985 | bitmap = ida->free_bitmap; |
| 986 | ida->free_bitmap = NULL; |
| 987 | spin_unlock_irqrestore(&ida->idr.lock, flags); |
| 988 | |
| 989 | if (!bitmap) |
| 990 | return -EAGAIN; |
| 991 | |
| 992 | memset(bitmap, 0, sizeof(struct ida_bitmap)); |
Nadia Derbey | 3219b3b | 2008-07-25 01:48:00 -0700 | [diff] [blame] | 993 | rcu_assign_pointer(pa[0]->ary[idr_id & IDR_MASK], |
| 994 | (void *)bitmap); |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 995 | pa[0]->count++; |
| 996 | } |
| 997 | |
| 998 | /* lookup for empty slot */ |
| 999 | t = find_next_zero_bit(bitmap->bitmap, IDA_BITMAP_BITS, offset); |
| 1000 | if (t == IDA_BITMAP_BITS) { |
| 1001 | /* no empty slot after offset, continue to the next chunk */ |
| 1002 | idr_id++; |
| 1003 | offset = 0; |
| 1004 | goto restart; |
| 1005 | } |
| 1006 | |
| 1007 | id = idr_id * IDA_BITMAP_BITS + t; |
Fengguang Wu | 125c4c7 | 2012-10-04 17:13:15 -0700 | [diff] [blame] | 1008 | if (id >= MAX_IDR_BIT) |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 1009 | return -ENOSPC; |
| 1010 | |
| 1011 | __set_bit(t, bitmap->bitmap); |
| 1012 | if (++bitmap->nr_busy == IDA_BITMAP_BITS) |
| 1013 | idr_mark_full(pa, idr_id); |
| 1014 | |
| 1015 | *p_id = id; |
| 1016 | |
| 1017 | /* Each leaf node can handle nearly a thousand slots and the |
| 1018 | * whole idea of ida is to have small memory foot print. |
| 1019 | * Throw away extra resources one by one after each successful |
| 1020 | * allocation. |
| 1021 | */ |
| 1022 | if (ida->idr.id_free_cnt || ida->free_bitmap) { |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 1023 | struct idr_layer *p = get_from_free_list(&ida->idr); |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 1024 | if (p) |
| 1025 | kmem_cache_free(idr_layer_cache, p); |
| 1026 | } |
| 1027 | |
| 1028 | return 0; |
| 1029 | } |
| 1030 | EXPORT_SYMBOL(ida_get_new_above); |
| 1031 | |
| 1032 | /** |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 1033 | * ida_remove - remove the given ID |
| 1034 | * @ida: ida handle |
| 1035 | * @id: ID to free |
| 1036 | */ |
| 1037 | void ida_remove(struct ida *ida, int id) |
| 1038 | { |
| 1039 | struct idr_layer *p = ida->idr.top; |
| 1040 | int shift = (ida->idr.layers - 1) * IDR_BITS; |
| 1041 | int idr_id = id / IDA_BITMAP_BITS; |
| 1042 | int offset = id % IDA_BITMAP_BITS; |
| 1043 | int n; |
| 1044 | struct ida_bitmap *bitmap; |
| 1045 | |
| 1046 | /* clear full bits while looking up the leaf idr_layer */ |
| 1047 | while ((shift > 0) && p) { |
| 1048 | n = (idr_id >> shift) & IDR_MASK; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 1049 | __clear_bit(n, p->bitmap); |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 1050 | p = p->ary[n]; |
| 1051 | shift -= IDR_BITS; |
| 1052 | } |
| 1053 | |
| 1054 | if (p == NULL) |
| 1055 | goto err; |
| 1056 | |
| 1057 | n = idr_id & IDR_MASK; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 1058 | __clear_bit(n, p->bitmap); |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 1059 | |
| 1060 | bitmap = (void *)p->ary[n]; |
| 1061 | if (!test_bit(offset, bitmap->bitmap)) |
| 1062 | goto err; |
| 1063 | |
| 1064 | /* update bitmap and remove it if empty */ |
| 1065 | __clear_bit(offset, bitmap->bitmap); |
| 1066 | if (--bitmap->nr_busy == 0) { |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 1067 | __set_bit(n, p->bitmap); /* to please idr_remove() */ |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 1068 | idr_remove(&ida->idr, idr_id); |
| 1069 | free_bitmap(ida, bitmap); |
| 1070 | } |
| 1071 | |
| 1072 | return; |
| 1073 | |
| 1074 | err: |
Jean Delvare | dd04b45 | 2013-07-03 15:08:47 -0700 | [diff] [blame] | 1075 | 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] | 1076 | } |
| 1077 | EXPORT_SYMBOL(ida_remove); |
| 1078 | |
| 1079 | /** |
| 1080 | * ida_destroy - release all cached layers within an ida tree |
Naohiro Aota | ea24ea8 | 2010-08-31 00:37:03 +0900 | [diff] [blame] | 1081 | * @ida: ida handle |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 1082 | */ |
| 1083 | void ida_destroy(struct ida *ida) |
| 1084 | { |
| 1085 | idr_destroy(&ida->idr); |
| 1086 | kfree(ida->free_bitmap); |
| 1087 | } |
| 1088 | EXPORT_SYMBOL(ida_destroy); |
| 1089 | |
| 1090 | /** |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 1091 | * ida_simple_get - get a new id. |
| 1092 | * @ida: the (initialized) ida. |
| 1093 | * @start: the minimum id (inclusive, < 0x8000000) |
| 1094 | * @end: the maximum id (exclusive, < 0x8000000 or 0) |
| 1095 | * @gfp_mask: memory allocation flags |
| 1096 | * |
| 1097 | * Allocates an id in the range start <= id < end, or returns -ENOSPC. |
| 1098 | * On memory allocation failure, returns -ENOMEM. |
| 1099 | * |
| 1100 | * Use ida_simple_remove() to get rid of an id. |
| 1101 | */ |
| 1102 | int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end, |
| 1103 | gfp_t gfp_mask) |
| 1104 | { |
| 1105 | int ret, id; |
| 1106 | unsigned int max; |
Tejun Heo | 46cbc1d | 2011-11-02 13:38:46 -0700 | [diff] [blame] | 1107 | unsigned long flags; |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 1108 | |
| 1109 | BUG_ON((int)start < 0); |
| 1110 | BUG_ON((int)end < 0); |
| 1111 | |
| 1112 | if (end == 0) |
| 1113 | max = 0x80000000; |
| 1114 | else { |
| 1115 | BUG_ON(end < start); |
| 1116 | max = end - 1; |
| 1117 | } |
| 1118 | |
| 1119 | again: |
| 1120 | if (!ida_pre_get(ida, gfp_mask)) |
| 1121 | return -ENOMEM; |
| 1122 | |
Tejun Heo | 46cbc1d | 2011-11-02 13:38:46 -0700 | [diff] [blame] | 1123 | spin_lock_irqsave(&simple_ida_lock, flags); |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 1124 | ret = ida_get_new_above(ida, start, &id); |
| 1125 | if (!ret) { |
| 1126 | if (id > max) { |
| 1127 | ida_remove(ida, id); |
| 1128 | ret = -ENOSPC; |
| 1129 | } else { |
| 1130 | ret = id; |
| 1131 | } |
| 1132 | } |
Tejun Heo | 46cbc1d | 2011-11-02 13:38:46 -0700 | [diff] [blame] | 1133 | spin_unlock_irqrestore(&simple_ida_lock, flags); |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 1134 | |
| 1135 | if (unlikely(ret == -EAGAIN)) |
| 1136 | goto again; |
| 1137 | |
| 1138 | return ret; |
| 1139 | } |
| 1140 | EXPORT_SYMBOL(ida_simple_get); |
| 1141 | |
| 1142 | /** |
| 1143 | * ida_simple_remove - remove an allocated id. |
| 1144 | * @ida: the (initialized) ida. |
| 1145 | * @id: the id returned by ida_simple_get. |
| 1146 | */ |
| 1147 | void ida_simple_remove(struct ida *ida, unsigned int id) |
| 1148 | { |
Tejun Heo | 46cbc1d | 2011-11-02 13:38:46 -0700 | [diff] [blame] | 1149 | unsigned long flags; |
| 1150 | |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 1151 | BUG_ON((int)id < 0); |
Tejun Heo | 46cbc1d | 2011-11-02 13:38:46 -0700 | [diff] [blame] | 1152 | spin_lock_irqsave(&simple_ida_lock, flags); |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 1153 | ida_remove(ida, id); |
Tejun Heo | 46cbc1d | 2011-11-02 13:38:46 -0700 | [diff] [blame] | 1154 | spin_unlock_irqrestore(&simple_ida_lock, flags); |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 1155 | } |
| 1156 | EXPORT_SYMBOL(ida_simple_remove); |
| 1157 | |
| 1158 | /** |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 1159 | * ida_init - initialize ida handle |
| 1160 | * @ida: ida handle |
| 1161 | * |
| 1162 | * This function is use to set up the handle (@ida) that you will pass |
| 1163 | * to the rest of the functions. |
| 1164 | */ |
| 1165 | void ida_init(struct ida *ida) |
| 1166 | { |
| 1167 | memset(ida, 0, sizeof(struct ida)); |
| 1168 | idr_init(&ida->idr); |
| 1169 | |
| 1170 | } |
| 1171 | EXPORT_SYMBOL(ida_init); |