| 1 | /* $NetBSD: linux_idr.c,v 1.5 2015/01/01 01:15:43 mrg Exp $ */ |
| 2 | |
| 3 | /*- |
| 4 | * Copyright (c) 2013 The NetBSD Foundation, Inc. |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * This code is derived from software contributed to The NetBSD Foundation |
| 8 | * by Taylor R. Campbell. |
| 9 | * |
| 10 | * Redistribution and use in source and binary forms, with or without |
| 11 | * modification, are permitted provided that the following conditions |
| 12 | * are met: |
| 13 | * 1. Redistributions of source code must retain the above copyright |
| 14 | * notice, this list of conditions and the following disclaimer. |
| 15 | * 2. Redistributions in binary form must reproduce the above copyright |
| 16 | * notice, this list of conditions and the following disclaimer in the |
| 17 | * documentation and/or other materials provided with the distribution. |
| 18 | * |
| 19 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
| 20 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
| 21 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| 22 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
| 23 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| 24 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| 25 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 26 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| 27 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 28 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| 29 | * POSSIBILITY OF SUCH DAMAGE. |
| 30 | */ |
| 31 | |
| 32 | #include <sys/cdefs.h> |
| 33 | __KERNEL_RCSID(0, "$NetBSD: linux_idr.c,v 1.5 2015/01/01 01:15:43 mrg Exp $" ); |
| 34 | |
| 35 | #include <sys/param.h> |
| 36 | #include <sys/atomic.h> |
| 37 | #include <sys/rbtree.h> |
| 38 | |
| 39 | #include <linux/err.h> |
| 40 | #include <linux/idr.h> |
| 41 | #include <linux/slab.h> |
| 42 | |
| 43 | struct idr_node { |
| 44 | rb_node_t in_rb_node; |
| 45 | int in_index; |
| 46 | void *in_data; |
| 47 | SIMPLEQ_ENTRY(idr_node) in_list; |
| 48 | }; |
| 49 | SIMPLEQ_HEAD(idr_head, idr_node); |
| 50 | |
| 51 | static struct { |
| 52 | kmutex_t lock; |
| 53 | struct idr_head preloaded_nodes; |
| 54 | struct idr_head discarded_nodes; |
| 55 | } idr_cache __cacheline_aligned; |
| 56 | |
| 57 | int |
| 58 | linux_idr_module_init(void) |
| 59 | { |
| 60 | |
| 61 | mutex_init(&idr_cache.lock, MUTEX_DEFAULT, IPL_VM); |
| 62 | SIMPLEQ_INIT(&idr_cache.preloaded_nodes); |
| 63 | SIMPLEQ_INIT(&idr_cache.discarded_nodes); |
| 64 | return 0; |
| 65 | } |
| 66 | |
| 67 | void |
| 68 | linux_idr_module_fini(void) |
| 69 | { |
| 70 | |
| 71 | KASSERT(SIMPLEQ_EMPTY(&idr_cache.discarded_nodes)); |
| 72 | KASSERT(SIMPLEQ_EMPTY(&idr_cache.preloaded_nodes)); |
| 73 | mutex_destroy(&idr_cache.lock); |
| 74 | } |
| 75 | |
| 76 | static signed int idr_tree_compare_nodes(void *, const void *, const void *); |
| 77 | static signed int idr_tree_compare_key(void *, const void *, const void *); |
| 78 | |
| 79 | static const rb_tree_ops_t idr_rb_ops = { |
| 80 | .rbto_compare_nodes = &idr_tree_compare_nodes, |
| 81 | .rbto_compare_key = &idr_tree_compare_key, |
| 82 | .rbto_node_offset = offsetof(struct idr_node, in_rb_node), |
| 83 | .rbto_context = NULL, |
| 84 | }; |
| 85 | |
| 86 | static signed int |
| 87 | idr_tree_compare_nodes(void *ctx __unused, const void *na, const void *nb) |
| 88 | { |
| 89 | const int a = ((const struct idr_node *)na)->in_index; |
| 90 | const int b = ((const struct idr_node *)nb)->in_index; |
| 91 | |
| 92 | if (a < b) |
| 93 | return -1; |
| 94 | else if (b < a) |
| 95 | return +1; |
| 96 | else |
| 97 | return 0; |
| 98 | } |
| 99 | |
| 100 | static signed int |
| 101 | idr_tree_compare_key(void *ctx __unused, const void *n, const void *key) |
| 102 | { |
| 103 | const int a = ((const struct idr_node *)n)->in_index; |
| 104 | const int b = *(const int *)key; |
| 105 | |
| 106 | if (a < b) |
| 107 | return -1; |
| 108 | else if (b < a) |
| 109 | return +1; |
| 110 | else |
| 111 | return 0; |
| 112 | } |
| 113 | |
| 114 | void |
| 115 | idr_init(struct idr *idr) |
| 116 | { |
| 117 | |
| 118 | mutex_init(&idr->idr_lock, MUTEX_DEFAULT, IPL_VM); |
| 119 | rb_tree_init(&idr->idr_tree, &idr_rb_ops); |
| 120 | } |
| 121 | |
| 122 | void |
| 123 | idr_destroy(struct idr *idr) |
| 124 | { |
| 125 | |
| 126 | #if 0 /* XXX No rb_tree_destroy? */ |
| 127 | rb_tree_destroy(&idr->idr_tree); |
| 128 | #endif |
| 129 | mutex_destroy(&idr->idr_lock); |
| 130 | } |
| 131 | |
| 132 | bool |
| 133 | idr_is_empty(struct idr *idr) |
| 134 | { |
| 135 | |
| 136 | return (RB_TREE_MIN(&idr->idr_tree) == NULL); |
| 137 | } |
| 138 | |
| 139 | void * |
| 140 | idr_find(struct idr *idr, int id) |
| 141 | { |
| 142 | const struct idr_node *node; |
| 143 | void *data; |
| 144 | |
| 145 | mutex_spin_enter(&idr->idr_lock); |
| 146 | node = rb_tree_find_node(&idr->idr_tree, &id); |
| 147 | data = (node == NULL? NULL : node->in_data); |
| 148 | mutex_spin_exit(&idr->idr_lock); |
| 149 | |
| 150 | return data; |
| 151 | } |
| 152 | |
| 153 | void * |
| 154 | idr_replace(struct idr *idr, void *replacement, int id) |
| 155 | { |
| 156 | struct idr_node *node; |
| 157 | void *result; |
| 158 | |
| 159 | mutex_spin_enter(&idr->idr_lock); |
| 160 | node = rb_tree_find_node(&idr->idr_tree, &id); |
| 161 | if (node == NULL) { |
| 162 | result = ERR_PTR(-ENOENT); |
| 163 | } else { |
| 164 | result = node->in_data; |
| 165 | node->in_data = replacement; |
| 166 | } |
| 167 | mutex_spin_exit(&idr->idr_lock); |
| 168 | |
| 169 | return result; |
| 170 | } |
| 171 | |
| 172 | void |
| 173 | idr_remove(struct idr *idr, int id) |
| 174 | { |
| 175 | struct idr_node *node; |
| 176 | |
| 177 | mutex_spin_enter(&idr->idr_lock); |
| 178 | node = rb_tree_find_node(&idr->idr_tree, &id); |
| 179 | KASSERTMSG((node != NULL), "idr %p has no entry for id %d" , idr, id); |
| 180 | rb_tree_remove_node(&idr->idr_tree, node); |
| 181 | mutex_spin_exit(&idr->idr_lock); |
| 182 | kfree(node); |
| 183 | } |
| 184 | |
| 185 | void |
| 186 | idr_preload(gfp_t gfp) |
| 187 | { |
| 188 | struct idr_node *node; |
| 189 | |
| 190 | if (ISSET(gfp, __GFP_WAIT)) |
| 191 | ASSERT_SLEEPABLE(); |
| 192 | |
| 193 | node = kmalloc(sizeof(*node), gfp); |
| 194 | if (node == NULL) |
| 195 | return; |
| 196 | |
| 197 | mutex_spin_enter(&idr_cache.lock); |
| 198 | SIMPLEQ_INSERT_TAIL(&idr_cache.preloaded_nodes, node, in_list); |
| 199 | mutex_spin_exit(&idr_cache.lock); |
| 200 | } |
| 201 | |
| 202 | int |
| 203 | idr_alloc(struct idr *idr, void *data, int start, int end, gfp_t gfp) |
| 204 | { |
| 205 | int maximum = (end <= 0? INT_MAX : (end - 1)); |
| 206 | struct idr_node *node, *search, *collision __diagused; |
| 207 | int id = start; |
| 208 | |
| 209 | /* Sanity-check inputs. */ |
| 210 | if (ISSET(gfp, __GFP_WAIT)) |
| 211 | ASSERT_SLEEPABLE(); |
| 212 | if (__predict_false(start < 0)) |
| 213 | return -EINVAL; |
| 214 | if (__predict_false(maximum < start)) |
| 215 | return -ENOSPC; |
| 216 | |
| 217 | /* Grab a node allocated by idr_preload. */ |
| 218 | mutex_spin_enter(&idr_cache.lock); |
| 219 | KASSERTMSG(!SIMPLEQ_EMPTY(&idr_cache.preloaded_nodes), |
| 220 | "missing call to idr_preload" ); |
| 221 | node = SIMPLEQ_FIRST(&idr_cache.preloaded_nodes); |
| 222 | SIMPLEQ_REMOVE_HEAD(&idr_cache.preloaded_nodes, in_list); |
| 223 | mutex_spin_exit(&idr_cache.lock); |
| 224 | |
| 225 | /* Find an id. */ |
| 226 | mutex_spin_enter(&idr->idr_lock); |
| 227 | search = rb_tree_find_node_geq(&idr->idr_tree, &start); |
| 228 | while ((search != NULL) && (search->in_index == id)) { |
| 229 | if (maximum <= id) { |
| 230 | id = -ENOSPC; |
| 231 | goto out; |
| 232 | } |
| 233 | search = rb_tree_iterate(&idr->idr_tree, search, RB_DIR_RIGHT); |
| 234 | id++; |
| 235 | } |
| 236 | node->in_index = id; |
| 237 | node->in_data = data; |
| 238 | collision = rb_tree_insert_node(&idr->idr_tree, node); |
| 239 | KASSERT(collision == node); |
| 240 | out: mutex_spin_exit(&idr->idr_lock); |
| 241 | |
| 242 | if (id < 0) { |
| 243 | /* Discard the node on failure. */ |
| 244 | mutex_spin_enter(&idr_cache.lock); |
| 245 | SIMPLEQ_INSERT_HEAD(&idr_cache.discarded_nodes, node, in_list); |
| 246 | mutex_spin_exit(&idr_cache.lock); |
| 247 | } |
| 248 | return id; |
| 249 | } |
| 250 | |
| 251 | void |
| 252 | idr_preload_end(void) |
| 253 | { |
| 254 | struct idr_head temp = SIMPLEQ_HEAD_INITIALIZER(temp); |
| 255 | struct idr_node *node, *next; |
| 256 | |
| 257 | mutex_spin_enter(&idr_cache.lock); |
| 258 | SIMPLEQ_FOREACH_SAFE(node, &idr_cache.discarded_nodes, in_list, next) { |
| 259 | SIMPLEQ_REMOVE_HEAD(&idr_cache.discarded_nodes, in_list); |
| 260 | SIMPLEQ_INSERT_HEAD(&temp, node, in_list); |
| 261 | } |
| 262 | mutex_spin_exit(&idr_cache.lock); |
| 263 | |
| 264 | SIMPLEQ_FOREACH_SAFE(node, &temp, in_list, next) { |
| 265 | SIMPLEQ_REMOVE_HEAD(&temp, in_list); |
| 266 | kfree(node); |
| 267 | } |
| 268 | } |
| 269 | |
| 270 | int |
| 271 | idr_for_each(struct idr *idr, int (*proc)(int, void *, void *), void *arg) |
| 272 | { |
| 273 | struct idr_node *node; |
| 274 | int error = 0; |
| 275 | |
| 276 | /* XXX Caller must exclude modifications. */ |
| 277 | membar_consumer(); |
| 278 | RB_TREE_FOREACH(node, &idr->idr_tree) { |
| 279 | error = (*proc)(node->in_index, node->in_data, arg); |
| 280 | if (error) |
| 281 | break; |
| 282 | } |
| 283 | |
| 284 | return error; |
| 285 | } |
| 286 | |