| 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* |
| 3 | * linux/mm/mempool.c |
| 4 | * |
| 5 | * memory buffer pool support. Such pools are mostly used |
| 6 | * for guaranteed, deadlock-free memory allocations during |
| 7 | * extreme VM load. |
| 8 | * |
| 9 | * started by Ingo Molnar, Copyright (C) 2001 |
| 10 | * debugging by David Rientjes, Copyright (C) 2015 |
| 11 | */ |
| 12 | |
| 13 | #include <linux/mm.h> |
| 14 | #include <linux/slab.h> |
| 15 | #include <linux/highmem.h> |
| 16 | #include <linux/kasan.h> |
| 17 | #include <linux/kmemleak.h> |
| 18 | #include <linux/export.h> |
| 19 | #include <linux/mempool.h> |
| 20 | #include <linux/writeback.h> |
| 21 | #include "slab.h" |
| 22 | |
| 23 | #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB_DEBUG_ON) |
| 24 | static void poison_error(mempool_t *pool, void *element, size_t size, |
| 25 | size_t byte) |
| 26 | { |
| 27 | const int nr = pool->curr_nr; |
| 28 | const int start = max_t(int, byte - (BITS_PER_LONG / 8), 0); |
| 29 | const int end = min_t(int, byte + (BITS_PER_LONG / 8), size); |
| 30 | int i; |
| 31 | |
| 32 | pr_err("BUG: mempool element poison mismatch\n"); |
| 33 | pr_err("Mempool %p size %zu\n", pool, size); |
| 34 | pr_err(" nr=%d @ %p: %s0x", nr, element, start > 0 ? "... " : ""); |
| 35 | for (i = start; i < end; i++) |
| 36 | pr_cont("%x ", *(u8 *)(element + i)); |
| 37 | pr_cont("%s\n", end < size ? "..." : ""); |
| 38 | dump_stack(); |
| 39 | } |
| 40 | |
| 41 | static void __check_element(mempool_t *pool, void *element, size_t size) |
| 42 | { |
| 43 | u8 *obj = element; |
| 44 | size_t i; |
| 45 | |
| 46 | for (i = 0; i < size; i++) { |
| 47 | u8 exp = (i < size - 1) ? POISON_FREE : POISON_END; |
| 48 | |
| 49 | if (obj[i] != exp) { |
| 50 | poison_error(pool, element, size, i); |
| 51 | return; |
| 52 | } |
| 53 | } |
| 54 | memset(obj, POISON_INUSE, size); |
| 55 | } |
| 56 | |
| 57 | static void check_element(mempool_t *pool, void *element) |
| 58 | { |
| 59 | /* Mempools backed by slab allocator */ |
| 60 | if (pool->free == mempool_kfree) { |
| 61 | __check_element(pool, element, (size_t)pool->pool_data); |
| 62 | } else if (pool->free == mempool_free_slab) { |
| 63 | __check_element(pool, element, kmem_cache_size(pool->pool_data)); |
| 64 | } else if (pool->free == mempool_free_pages) { |
| 65 | /* Mempools backed by page allocator */ |
| 66 | int order = (int)(long)pool->pool_data; |
| 67 | void *addr = kmap_atomic((struct page *)element); |
| 68 | |
| 69 | __check_element(pool, addr, 1UL << (PAGE_SHIFT + order)); |
| 70 | kunmap_atomic(addr); |
| 71 | } |
| 72 | } |
| 73 | |
| 74 | static void __poison_element(void *element, size_t size) |
| 75 | { |
| 76 | u8 *obj = element; |
| 77 | |
| 78 | memset(obj, POISON_FREE, size - 1); |
| 79 | obj[size - 1] = POISON_END; |
| 80 | } |
| 81 | |
| 82 | static void poison_element(mempool_t *pool, void *element) |
| 83 | { |
| 84 | /* Mempools backed by slab allocator */ |
| 85 | if (pool->alloc == mempool_kmalloc) { |
| 86 | __poison_element(element, (size_t)pool->pool_data); |
| 87 | } else if (pool->alloc == mempool_alloc_slab) { |
| 88 | __poison_element(element, kmem_cache_size(pool->pool_data)); |
| 89 | } else if (pool->alloc == mempool_alloc_pages) { |
| 90 | /* Mempools backed by page allocator */ |
| 91 | int order = (int)(long)pool->pool_data; |
| 92 | void *addr = kmap_atomic((struct page *)element); |
| 93 | |
| 94 | __poison_element(addr, 1UL << (PAGE_SHIFT + order)); |
| 95 | kunmap_atomic(addr); |
| 96 | } |
| 97 | } |
| 98 | #else /* CONFIG_DEBUG_SLAB || CONFIG_SLUB_DEBUG_ON */ |
| 99 | static inline void check_element(mempool_t *pool, void *element) |
| 100 | { |
| 101 | } |
| 102 | static inline void poison_element(mempool_t *pool, void *element) |
| 103 | { |
| 104 | } |
| 105 | #endif /* CONFIG_DEBUG_SLAB || CONFIG_SLUB_DEBUG_ON */ |
| 106 | |
| 107 | static __always_inline void kasan_poison_element(mempool_t *pool, void *element) |
| 108 | { |
| 109 | if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc) |
| 110 | kasan_slab_free_mempool(element); |
| 111 | else if (pool->alloc == mempool_alloc_pages) |
| 112 | kasan_poison_pages(element, (unsigned long)pool->pool_data, |
| 113 | false); |
| 114 | } |
| 115 | |
| 116 | static void kasan_unpoison_element(mempool_t *pool, void *element) |
| 117 | { |
| 118 | if (pool->alloc == mempool_kmalloc) |
| 119 | kasan_unpoison_range(element, (size_t)pool->pool_data); |
| 120 | else if (pool->alloc == mempool_alloc_slab) |
| 121 | kasan_unpoison_range(element, kmem_cache_size(pool->pool_data)); |
| 122 | else if (pool->alloc == mempool_alloc_pages) |
| 123 | kasan_unpoison_pages(element, (unsigned long)pool->pool_data, |
| 124 | false); |
| 125 | } |
| 126 | |
| 127 | static __always_inline void add_element(mempool_t *pool, void *element) |
| 128 | { |
| 129 | BUG_ON(pool->curr_nr >= pool->min_nr); |
| 130 | poison_element(pool, element); |
| 131 | kasan_poison_element(pool, element); |
| 132 | pool->elements[pool->curr_nr++] = element; |
| 133 | } |
| 134 | |
| 135 | static void *remove_element(mempool_t *pool) |
| 136 | { |
| 137 | void *element = pool->elements[--pool->curr_nr]; |
| 138 | |
| 139 | BUG_ON(pool->curr_nr < 0); |
| 140 | kasan_unpoison_element(pool, element); |
| 141 | check_element(pool, element); |
| 142 | return element; |
| 143 | } |
| 144 | |
| 145 | /** |
| 146 | * mempool_exit - exit a mempool initialized with mempool_init() |
| 147 | * @pool: pointer to the memory pool which was initialized with |
| 148 | * mempool_init(). |
| 149 | * |
| 150 | * Free all reserved elements in @pool and @pool itself. This function |
| 151 | * only sleeps if the free_fn() function sleeps. |
| 152 | * |
| 153 | * May be called on a zeroed but uninitialized mempool (i.e. allocated with |
| 154 | * kzalloc()). |
| 155 | */ |
| 156 | void mempool_exit(mempool_t *pool) |
| 157 | { |
| 158 | while (pool->curr_nr) { |
| 159 | void *element = remove_element(pool); |
| 160 | pool->free(element, pool->pool_data); |
| 161 | } |
| 162 | kfree(pool->elements); |
| 163 | pool->elements = NULL; |
| 164 | } |
| 165 | EXPORT_SYMBOL(mempool_exit); |
| 166 | |
| 167 | /** |
| 168 | * mempool_destroy - deallocate a memory pool |
| 169 | * @pool: pointer to the memory pool which was allocated via |
| 170 | * mempool_create(). |
| 171 | * |
| 172 | * Free all reserved elements in @pool and @pool itself. This function |
| 173 | * only sleeps if the free_fn() function sleeps. |
| 174 | */ |
| 175 | void mempool_destroy(mempool_t *pool) |
| 176 | { |
| 177 | if (unlikely(!pool)) |
| 178 | return; |
| 179 | |
| 180 | mempool_exit(pool); |
| 181 | kfree(pool); |
| 182 | } |
| 183 | EXPORT_SYMBOL(mempool_destroy); |
| 184 | |
| 185 | int mempool_init_node(mempool_t *pool, int min_nr, mempool_alloc_t *alloc_fn, |
| 186 | mempool_free_t *free_fn, void *pool_data, |
| 187 | gfp_t gfp_mask, int node_id) |
| 188 | { |
| 189 | spin_lock_init(&pool->lock); |
| 190 | pool->min_nr = min_nr; |
| 191 | pool->pool_data = pool_data; |
| 192 | pool->alloc = alloc_fn; |
| 193 | pool->free = free_fn; |
| 194 | init_waitqueue_head(&pool->wait); |
| 195 | |
| 196 | pool->elements = kmalloc_array_node(min_nr, sizeof(void *), |
| 197 | gfp_mask, node_id); |
| 198 | if (!pool->elements) |
| 199 | return -ENOMEM; |
| 200 | |
| 201 | /* |
| 202 | * First pre-allocate the guaranteed number of buffers. |
| 203 | */ |
| 204 | while (pool->curr_nr < pool->min_nr) { |
| 205 | void *element; |
| 206 | |
| 207 | element = pool->alloc(gfp_mask, pool->pool_data); |
| 208 | if (unlikely(!element)) { |
| 209 | mempool_exit(pool); |
| 210 | return -ENOMEM; |
| 211 | } |
| 212 | add_element(pool, element); |
| 213 | } |
| 214 | |
| 215 | return 0; |
| 216 | } |
| 217 | EXPORT_SYMBOL(mempool_init_node); |
| 218 | |
| 219 | /** |
| 220 | * mempool_init - initialize a memory pool |
| 221 | * @pool: pointer to the memory pool that should be initialized |
| 222 | * @min_nr: the minimum number of elements guaranteed to be |
| 223 | * allocated for this pool. |
| 224 | * @alloc_fn: user-defined element-allocation function. |
| 225 | * @free_fn: user-defined element-freeing function. |
| 226 | * @pool_data: optional private data available to the user-defined functions. |
| 227 | * |
| 228 | * Like mempool_create(), but initializes the pool in (i.e. embedded in another |
| 229 | * structure). |
| 230 | * |
| 231 | * Return: %0 on success, negative error code otherwise. |
| 232 | */ |
| 233 | int mempool_init(mempool_t *pool, int min_nr, mempool_alloc_t *alloc_fn, |
| 234 | mempool_free_t *free_fn, void *pool_data) |
| 235 | { |
| 236 | return mempool_init_node(pool, min_nr, alloc_fn, free_fn, |
| 237 | pool_data, GFP_KERNEL, NUMA_NO_NODE); |
| 238 | |
| 239 | } |
| 240 | EXPORT_SYMBOL(mempool_init); |
| 241 | |
| 242 | /** |
| 243 | * mempool_create - create a memory pool |
| 244 | * @min_nr: the minimum number of elements guaranteed to be |
| 245 | * allocated for this pool. |
| 246 | * @alloc_fn: user-defined element-allocation function. |
| 247 | * @free_fn: user-defined element-freeing function. |
| 248 | * @pool_data: optional private data available to the user-defined functions. |
| 249 | * |
| 250 | * this function creates and allocates a guaranteed size, preallocated |
| 251 | * memory pool. The pool can be used from the mempool_alloc() and mempool_free() |
| 252 | * functions. This function might sleep. Both the alloc_fn() and the free_fn() |
| 253 | * functions might sleep - as long as the mempool_alloc() function is not called |
| 254 | * from IRQ contexts. |
| 255 | * |
| 256 | * Return: pointer to the created memory pool object or %NULL on error. |
| 257 | */ |
| 258 | mempool_t *mempool_create(int min_nr, mempool_alloc_t *alloc_fn, |
| 259 | mempool_free_t *free_fn, void *pool_data) |
| 260 | { |
| 261 | return mempool_create_node(min_nr, alloc_fn, free_fn, pool_data, |
| 262 | GFP_KERNEL, NUMA_NO_NODE); |
| 263 | } |
| 264 | EXPORT_SYMBOL(mempool_create); |
| 265 | |
| 266 | mempool_t *mempool_create_node(int min_nr, mempool_alloc_t *alloc_fn, |
| 267 | mempool_free_t *free_fn, void *pool_data, |
| 268 | gfp_t gfp_mask, int node_id) |
| 269 | { |
| 270 | mempool_t *pool; |
| 271 | |
| 272 | pool = kzalloc_node(sizeof(*pool), gfp_mask, node_id); |
| 273 | if (!pool) |
| 274 | return NULL; |
| 275 | |
| 276 | if (mempool_init_node(pool, min_nr, alloc_fn, free_fn, pool_data, |
| 277 | gfp_mask, node_id)) { |
| 278 | kfree(pool); |
| 279 | return NULL; |
| 280 | } |
| 281 | |
| 282 | return pool; |
| 283 | } |
| 284 | EXPORT_SYMBOL(mempool_create_node); |
| 285 | |
| 286 | /** |
| 287 | * mempool_resize - resize an existing memory pool |
| 288 | * @pool: pointer to the memory pool which was allocated via |
| 289 | * mempool_create(). |
| 290 | * @new_min_nr: the new minimum number of elements guaranteed to be |
| 291 | * allocated for this pool. |
| 292 | * |
| 293 | * This function shrinks/grows the pool. In the case of growing, |
| 294 | * it cannot be guaranteed that the pool will be grown to the new |
| 295 | * size immediately, but new mempool_free() calls will refill it. |
| 296 | * This function may sleep. |
| 297 | * |
| 298 | * Note, the caller must guarantee that no mempool_destroy is called |
| 299 | * while this function is running. mempool_alloc() & mempool_free() |
| 300 | * might be called (eg. from IRQ contexts) while this function executes. |
| 301 | * |
| 302 | * Return: %0 on success, negative error code otherwise. |
| 303 | */ |
| 304 | int mempool_resize(mempool_t *pool, int new_min_nr) |
| 305 | { |
| 306 | void *element; |
| 307 | void **new_elements; |
| 308 | unsigned long flags; |
| 309 | |
| 310 | BUG_ON(new_min_nr <= 0); |
| 311 | might_sleep(); |
| 312 | |
| 313 | spin_lock_irqsave(&pool->lock, flags); |
| 314 | if (new_min_nr <= pool->min_nr) { |
| 315 | while (new_min_nr < pool->curr_nr) { |
| 316 | element = remove_element(pool); |
| 317 | spin_unlock_irqrestore(&pool->lock, flags); |
| 318 | pool->free(element, pool->pool_data); |
| 319 | spin_lock_irqsave(&pool->lock, flags); |
| 320 | } |
| 321 | pool->min_nr = new_min_nr; |
| 322 | goto out_unlock; |
| 323 | } |
| 324 | spin_unlock_irqrestore(&pool->lock, flags); |
| 325 | |
| 326 | /* Grow the pool */ |
| 327 | new_elements = kmalloc_array(new_min_nr, sizeof(*new_elements), |
| 328 | GFP_KERNEL); |
| 329 | if (!new_elements) |
| 330 | return -ENOMEM; |
| 331 | |
| 332 | spin_lock_irqsave(&pool->lock, flags); |
| 333 | if (unlikely(new_min_nr <= pool->min_nr)) { |
| 334 | /* Raced, other resize will do our work */ |
| 335 | spin_unlock_irqrestore(&pool->lock, flags); |
| 336 | kfree(new_elements); |
| 337 | goto out; |
| 338 | } |
| 339 | memcpy(new_elements, pool->elements, |
| 340 | pool->curr_nr * sizeof(*new_elements)); |
| 341 | kfree(pool->elements); |
| 342 | pool->elements = new_elements; |
| 343 | pool->min_nr = new_min_nr; |
| 344 | |
| 345 | while (pool->curr_nr < pool->min_nr) { |
| 346 | spin_unlock_irqrestore(&pool->lock, flags); |
| 347 | element = pool->alloc(GFP_KERNEL, pool->pool_data); |
| 348 | if (!element) |
| 349 | goto out; |
| 350 | spin_lock_irqsave(&pool->lock, flags); |
| 351 | if (pool->curr_nr < pool->min_nr) { |
| 352 | add_element(pool, element); |
| 353 | } else { |
| 354 | spin_unlock_irqrestore(&pool->lock, flags); |
| 355 | pool->free(element, pool->pool_data); /* Raced */ |
| 356 | goto out; |
| 357 | } |
| 358 | } |
| 359 | out_unlock: |
| 360 | spin_unlock_irqrestore(&pool->lock, flags); |
| 361 | out: |
| 362 | return 0; |
| 363 | } |
| 364 | EXPORT_SYMBOL(mempool_resize); |
| 365 | |
| 366 | /** |
| 367 | * mempool_alloc - allocate an element from a specific memory pool |
| 368 | * @pool: pointer to the memory pool which was allocated via |
| 369 | * mempool_create(). |
| 370 | * @gfp_mask: the usual allocation bitmask. |
| 371 | * |
| 372 | * this function only sleeps if the alloc_fn() function sleeps or |
| 373 | * returns NULL. Note that due to preallocation, this function |
| 374 | * *never* fails when called from process contexts. (it might |
| 375 | * fail if called from an IRQ context.) |
| 376 | * Note: using __GFP_ZERO is not supported. |
| 377 | * |
| 378 | * Return: pointer to the allocated element or %NULL on error. |
| 379 | */ |
| 380 | void *mempool_alloc(mempool_t *pool, gfp_t gfp_mask) |
| 381 | { |
| 382 | void *element; |
| 383 | unsigned long flags; |
| 384 | wait_queue_entry_t wait; |
| 385 | gfp_t gfp_temp; |
| 386 | |
| 387 | VM_WARN_ON_ONCE(gfp_mask & __GFP_ZERO); |
| 388 | might_alloc(gfp_mask); |
| 389 | |
| 390 | gfp_mask |= __GFP_NOMEMALLOC; /* don't allocate emergency reserves */ |
| 391 | gfp_mask |= __GFP_NORETRY; /* don't loop in __alloc_pages */ |
| 392 | gfp_mask |= __GFP_NOWARN; /* failures are OK */ |
| 393 | |
| 394 | gfp_temp = gfp_mask & ~(__GFP_DIRECT_RECLAIM|__GFP_IO); |
| 395 | |
| 396 | repeat_alloc: |
| 397 | |
| 398 | element = pool->alloc(gfp_temp, pool->pool_data); |
| 399 | if (likely(element != NULL)) |
| 400 | return element; |
| 401 | |
| 402 | spin_lock_irqsave(&pool->lock, flags); |
| 403 | if (likely(pool->curr_nr)) { |
| 404 | element = remove_element(pool); |
| 405 | spin_unlock_irqrestore(&pool->lock, flags); |
| 406 | /* paired with rmb in mempool_free(), read comment there */ |
| 407 | smp_wmb(); |
| 408 | /* |
| 409 | * Update the allocation stack trace as this is more useful |
| 410 | * for debugging. |
| 411 | */ |
| 412 | kmemleak_update_trace(element); |
| 413 | return element; |
| 414 | } |
| 415 | |
| 416 | /* |
| 417 | * We use gfp mask w/o direct reclaim or IO for the first round. If |
| 418 | * alloc failed with that and @pool was empty, retry immediately. |
| 419 | */ |
| 420 | if (gfp_temp != gfp_mask) { |
| 421 | spin_unlock_irqrestore(&pool->lock, flags); |
| 422 | gfp_temp = gfp_mask; |
| 423 | goto repeat_alloc; |
| 424 | } |
| 425 | |
| 426 | /* We must not sleep if !__GFP_DIRECT_RECLAIM */ |
| 427 | if (!(gfp_mask & __GFP_DIRECT_RECLAIM)) { |
| 428 | spin_unlock_irqrestore(&pool->lock, flags); |
| 429 | return NULL; |
| 430 | } |
| 431 | |
| 432 | /* Let's wait for someone else to return an element to @pool */ |
| 433 | init_wait(&wait); |
| 434 | prepare_to_wait(&pool->wait, &wait, TASK_UNINTERRUPTIBLE); |
| 435 | |
| 436 | spin_unlock_irqrestore(&pool->lock, flags); |
| 437 | |
| 438 | /* |
| 439 | * FIXME: this should be io_schedule(). The timeout is there as a |
| 440 | * workaround for some DM problems in 2.6.18. |
| 441 | */ |
| 442 | io_schedule_timeout(5*HZ); |
| 443 | |
| 444 | finish_wait(&pool->wait, &wait); |
| 445 | goto repeat_alloc; |
| 446 | } |
| 447 | EXPORT_SYMBOL(mempool_alloc); |
| 448 | |
| 449 | /** |
| 450 | * mempool_free - return an element to the pool. |
| 451 | * @element: pool element pointer. |
| 452 | * @pool: pointer to the memory pool which was allocated via |
| 453 | * mempool_create(). |
| 454 | * |
| 455 | * this function only sleeps if the free_fn() function sleeps. |
| 456 | */ |
| 457 | void mempool_free(void *element, mempool_t *pool) |
| 458 | { |
| 459 | unsigned long flags; |
| 460 | |
| 461 | if (unlikely(element == NULL)) |
| 462 | return; |
| 463 | |
| 464 | /* |
| 465 | * Paired with the wmb in mempool_alloc(). The preceding read is |
| 466 | * for @element and the following @pool->curr_nr. This ensures |
| 467 | * that the visible value of @pool->curr_nr is from after the |
| 468 | * allocation of @element. This is necessary for fringe cases |
| 469 | * where @element was passed to this task without going through |
| 470 | * barriers. |
| 471 | * |
| 472 | * For example, assume @p is %NULL at the beginning and one task |
| 473 | * performs "p = mempool_alloc(...);" while another task is doing |
| 474 | * "while (!p) cpu_relax(); mempool_free(p, ...);". This function |
| 475 | * may end up using curr_nr value which is from before allocation |
| 476 | * of @p without the following rmb. |
| 477 | */ |
| 478 | smp_rmb(); |
| 479 | |
| 480 | /* |
| 481 | * For correctness, we need a test which is guaranteed to trigger |
| 482 | * if curr_nr + #allocated == min_nr. Testing curr_nr < min_nr |
| 483 | * without locking achieves that and refilling as soon as possible |
| 484 | * is desirable. |
| 485 | * |
| 486 | * Because curr_nr visible here is always a value after the |
| 487 | * allocation of @element, any task which decremented curr_nr below |
| 488 | * min_nr is guaranteed to see curr_nr < min_nr unless curr_nr gets |
| 489 | * incremented to min_nr afterwards. If curr_nr gets incremented |
| 490 | * to min_nr after the allocation of @element, the elements |
| 491 | * allocated after that are subject to the same guarantee. |
| 492 | * |
| 493 | * Waiters happen iff curr_nr is 0 and the above guarantee also |
| 494 | * ensures that there will be frees which return elements to the |
| 495 | * pool waking up the waiters. |
| 496 | */ |
| 497 | if (unlikely(READ_ONCE(pool->curr_nr) < pool->min_nr)) { |
| 498 | spin_lock_irqsave(&pool->lock, flags); |
| 499 | if (likely(pool->curr_nr < pool->min_nr)) { |
| 500 | add_element(pool, element); |
| 501 | spin_unlock_irqrestore(&pool->lock, flags); |
| 502 | wake_up(&pool->wait); |
| 503 | return; |
| 504 | } |
| 505 | spin_unlock_irqrestore(&pool->lock, flags); |
| 506 | } |
| 507 | pool->free(element, pool->pool_data); |
| 508 | } |
| 509 | EXPORT_SYMBOL(mempool_free); |
| 510 | |
| 511 | /* |
| 512 | * A commonly used alloc and free fn. |
| 513 | */ |
| 514 | void *mempool_alloc_slab(gfp_t gfp_mask, void *pool_data) |
| 515 | { |
| 516 | struct kmem_cache *mem = pool_data; |
| 517 | VM_BUG_ON(mem->ctor); |
| 518 | return kmem_cache_alloc(mem, gfp_mask); |
| 519 | } |
| 520 | EXPORT_SYMBOL(mempool_alloc_slab); |
| 521 | |
| 522 | void mempool_free_slab(void *element, void *pool_data) |
| 523 | { |
| 524 | struct kmem_cache *mem = pool_data; |
| 525 | kmem_cache_free(mem, element); |
| 526 | } |
| 527 | EXPORT_SYMBOL(mempool_free_slab); |
| 528 | |
| 529 | /* |
| 530 | * A commonly used alloc and free fn that kmalloc/kfrees the amount of memory |
| 531 | * specified by pool_data |
| 532 | */ |
| 533 | void *mempool_kmalloc(gfp_t gfp_mask, void *pool_data) |
| 534 | { |
| 535 | size_t size = (size_t)pool_data; |
| 536 | return kmalloc(size, gfp_mask); |
| 537 | } |
| 538 | EXPORT_SYMBOL(mempool_kmalloc); |
| 539 | |
| 540 | void mempool_kfree(void *element, void *pool_data) |
| 541 | { |
| 542 | kfree(element); |
| 543 | } |
| 544 | EXPORT_SYMBOL(mempool_kfree); |
| 545 | |
| 546 | /* |
| 547 | * A simple mempool-backed page allocator that allocates pages |
| 548 | * of the order specified by pool_data. |
| 549 | */ |
| 550 | void *mempool_alloc_pages(gfp_t gfp_mask, void *pool_data) |
| 551 | { |
| 552 | int order = (int)(long)pool_data; |
| 553 | return alloc_pages(gfp_mask, order); |
| 554 | } |
| 555 | EXPORT_SYMBOL(mempool_alloc_pages); |
| 556 | |
| 557 | void mempool_free_pages(void *element, void *pool_data) |
| 558 | { |
| 559 | int order = (int)(long)pool_data; |
| 560 | __free_pages(element, order); |
| 561 | } |
| 562 | EXPORT_SYMBOL(mempool_free_pages); |