blob: 4c533bc51d733989f12c9f5e25cad713f647baea [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/mm/mempool.c
3 *
4 * memory buffer pool support. Such pools are mostly used
5 * for guaranteed, deadlock-free memory allocations during
6 * extreme VM load.
7 *
8 * started by Ingo Molnar, Copyright (C) 2001
David Rientjesbdfedb72015-04-15 16:14:17 -07009 * debugging by David Rientjes, Copyright (C) 2015
Linus Torvalds1da177e2005-04-16 15:20:36 -070010 */
11
12#include <linux/mm.h>
13#include <linux/slab.h>
David Rientjesbdfedb72015-04-15 16:14:17 -070014#include <linux/highmem.h>
Andrey Ryabinin92393612015-04-15 16:15:05 -070015#include <linux/kasan.h>
Catalin Marinas17411962014-06-06 14:38:19 -070016#include <linux/kmemleak.h>
Paul Gortmakerb95f1b312011-10-16 02:01:52 -040017#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#include <linux/mempool.h>
19#include <linux/blkdev.h>
20#include <linux/writeback.h>
David Rientjese244c9e2015-04-15 16:14:14 -070021#include "slab.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070022
David Rientjesbdfedb72015-04-15 16:14:17 -070023#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB_DEBUG_ON)
24static 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
41static 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
57static void check_element(mempool_t *pool, void *element)
58{
59 /* Mempools backed by slab allocator */
60 if (pool->free == mempool_free_slab || pool->free == mempool_kfree)
61 __check_element(pool, element, ksize(element));
62
63 /* Mempools backed by page allocator */
64 if (pool->free == mempool_free_pages) {
65 int order = (int)(long)pool->pool_data;
66 void *addr = kmap_atomic((struct page *)element);
67
68 __check_element(pool, addr, 1UL << (PAGE_SHIFT + order));
69 kunmap_atomic(addr);
70 }
71}
72
73static void __poison_element(void *element, size_t size)
74{
75 u8 *obj = element;
76
77 memset(obj, POISON_FREE, size - 1);
78 obj[size - 1] = POISON_END;
79}
80
81static void poison_element(mempool_t *pool, void *element)
82{
83 /* Mempools backed by slab allocator */
84 if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc)
85 __poison_element(element, ksize(element));
86
87 /* Mempools backed by page allocator */
88 if (pool->alloc == mempool_alloc_pages) {
89 int order = (int)(long)pool->pool_data;
90 void *addr = kmap_atomic((struct page *)element);
91
92 __poison_element(addr, 1UL << (PAGE_SHIFT + order));
93 kunmap_atomic(addr);
94 }
95}
96#else /* CONFIG_DEBUG_SLAB || CONFIG_SLUB_DEBUG_ON */
97static inline void check_element(mempool_t *pool, void *element)
98{
99}
100static inline void poison_element(mempool_t *pool, void *element)
101{
102}
103#endif /* CONFIG_DEBUG_SLAB || CONFIG_SLUB_DEBUG_ON */
104
Andrey Ryabinin92393612015-04-15 16:15:05 -0700105static void kasan_poison_element(mempool_t *pool, void *element)
106{
107 if (pool->alloc == mempool_alloc_slab)
108 kasan_slab_free(pool->pool_data, element);
109 if (pool->alloc == mempool_kmalloc)
110 kasan_kfree(element);
111 if (pool->alloc == mempool_alloc_pages)
112 kasan_free_pages(element, (unsigned long)pool->pool_data);
113}
114
115static void kasan_unpoison_element(mempool_t *pool, void *element)
116{
117 if (pool->alloc == mempool_alloc_slab)
118 kasan_slab_alloc(pool->pool_data, element);
119 if (pool->alloc == mempool_kmalloc)
120 kasan_krealloc(element, (size_t)pool->pool_data);
121 if (pool->alloc == mempool_alloc_pages)
122 kasan_alloc_pages(element, (unsigned long)pool->pool_data);
123}
124
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125static void add_element(mempool_t *pool, void *element)
126{
127 BUG_ON(pool->curr_nr >= pool->min_nr);
David Rientjesbdfedb72015-04-15 16:14:17 -0700128 poison_element(pool, element);
Andrey Ryabinin92393612015-04-15 16:15:05 -0700129 kasan_poison_element(pool, element);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 pool->elements[pool->curr_nr++] = element;
131}
132
133static void *remove_element(mempool_t *pool)
134{
David Rientjesbdfedb72015-04-15 16:14:17 -0700135 void *element = pool->elements[--pool->curr_nr];
136
137 BUG_ON(pool->curr_nr < 0);
138 check_element(pool, element);
Andrey Ryabinin92393612015-04-15 16:15:05 -0700139 kasan_unpoison_element(pool, element);
David Rientjesbdfedb72015-04-15 16:14:17 -0700140 return element;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141}
142
Tejun Heo0565d312012-01-10 15:08:26 -0800143/**
144 * mempool_destroy - deallocate a memory pool
145 * @pool: pointer to the memory pool which was allocated via
146 * mempool_create().
147 *
148 * Free all reserved elements in @pool and @pool itself. This function
149 * only sleeps if the free_fn() function sleeps.
150 */
151void mempool_destroy(mempool_t *pool)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152{
Sergey Senozhatsky4e3ca3e2015-09-08 15:00:53 -0700153 if (unlikely(!pool))
154 return;
155
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156 while (pool->curr_nr) {
157 void *element = remove_element(pool);
158 pool->free(element, pool->pool_data);
159 }
160 kfree(pool->elements);
161 kfree(pool);
162}
Tejun Heo0565d312012-01-10 15:08:26 -0800163EXPORT_SYMBOL(mempool_destroy);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164
165/**
166 * mempool_create - create a memory pool
167 * @min_nr: the minimum number of elements guaranteed to be
168 * allocated for this pool.
169 * @alloc_fn: user-defined element-allocation function.
170 * @free_fn: user-defined element-freeing function.
171 * @pool_data: optional private data available to the user-defined functions.
172 *
173 * this function creates and allocates a guaranteed size, preallocated
Robert P. J. Day72fd4a32007-02-10 01:45:59 -0800174 * memory pool. The pool can be used from the mempool_alloc() and mempool_free()
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 * functions. This function might sleep. Both the alloc_fn() and the free_fn()
Robert P. J. Day72fd4a32007-02-10 01:45:59 -0800176 * functions might sleep - as long as the mempool_alloc() function is not called
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177 * from IRQ contexts.
178 */
Christoph Lameter19460892005-06-23 00:08:19 -0700179mempool_t *mempool_create(int min_nr, mempool_alloc_t *alloc_fn,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 mempool_free_t *free_fn, void *pool_data)
181{
Tejun Heoa91a5ac2012-06-04 20:40:53 -0700182 return mempool_create_node(min_nr,alloc_fn,free_fn, pool_data,
183 GFP_KERNEL, NUMA_NO_NODE);
Christoph Lameter19460892005-06-23 00:08:19 -0700184}
185EXPORT_SYMBOL(mempool_create);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186
Christoph Lameter19460892005-06-23 00:08:19 -0700187mempool_t *mempool_create_node(int min_nr, mempool_alloc_t *alloc_fn,
Tejun Heoa91a5ac2012-06-04 20:40:53 -0700188 mempool_free_t *free_fn, void *pool_data,
189 gfp_t gfp_mask, int node_id)
Christoph Lameter19460892005-06-23 00:08:19 -0700190{
191 mempool_t *pool;
Joe Perches7b5219d2013-09-11 14:23:07 -0700192 pool = kzalloc_node(sizeof(*pool), gfp_mask, node_id);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 if (!pool)
194 return NULL;
Christoph Lameter19460892005-06-23 00:08:19 -0700195 pool->elements = kmalloc_node(min_nr * sizeof(void *),
Tejun Heoa91a5ac2012-06-04 20:40:53 -0700196 gfp_mask, node_id);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197 if (!pool->elements) {
198 kfree(pool);
199 return NULL;
200 }
201 spin_lock_init(&pool->lock);
202 pool->min_nr = min_nr;
203 pool->pool_data = pool_data;
204 init_waitqueue_head(&pool->wait);
205 pool->alloc = alloc_fn;
206 pool->free = free_fn;
207
208 /*
209 * First pre-allocate the guaranteed number of buffers.
210 */
211 while (pool->curr_nr < pool->min_nr) {
212 void *element;
213
Tejun Heoa91a5ac2012-06-04 20:40:53 -0700214 element = pool->alloc(gfp_mask, pool->pool_data);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215 if (unlikely(!element)) {
Tejun Heo0565d312012-01-10 15:08:26 -0800216 mempool_destroy(pool);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217 return NULL;
218 }
219 add_element(pool, element);
220 }
221 return pool;
222}
Christoph Lameter19460892005-06-23 00:08:19 -0700223EXPORT_SYMBOL(mempool_create_node);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224
225/**
226 * mempool_resize - resize an existing memory pool
227 * @pool: pointer to the memory pool which was allocated via
228 * mempool_create().
229 * @new_min_nr: the new minimum number of elements guaranteed to be
230 * allocated for this pool.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 *
232 * This function shrinks/grows the pool. In the case of growing,
233 * it cannot be guaranteed that the pool will be grown to the new
234 * size immediately, but new mempool_free() calls will refill it.
David Rientjes11d83362015-04-14 15:48:21 -0700235 * This function may sleep.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 *
237 * Note, the caller must guarantee that no mempool_destroy is called
238 * while this function is running. mempool_alloc() & mempool_free()
239 * might be called (eg. from IRQ contexts) while this function executes.
240 */
David Rientjes11d83362015-04-14 15:48:21 -0700241int mempool_resize(mempool_t *pool, int new_min_nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242{
243 void *element;
244 void **new_elements;
245 unsigned long flags;
246
247 BUG_ON(new_min_nr <= 0);
David Rientjes11d83362015-04-14 15:48:21 -0700248 might_sleep();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249
250 spin_lock_irqsave(&pool->lock, flags);
251 if (new_min_nr <= pool->min_nr) {
252 while (new_min_nr < pool->curr_nr) {
253 element = remove_element(pool);
254 spin_unlock_irqrestore(&pool->lock, flags);
255 pool->free(element, pool->pool_data);
256 spin_lock_irqsave(&pool->lock, flags);
257 }
258 pool->min_nr = new_min_nr;
259 goto out_unlock;
260 }
261 spin_unlock_irqrestore(&pool->lock, flags);
262
263 /* Grow the pool */
David Rientjes11d83362015-04-14 15:48:21 -0700264 new_elements = kmalloc_array(new_min_nr, sizeof(*new_elements),
265 GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266 if (!new_elements)
267 return -ENOMEM;
268
269 spin_lock_irqsave(&pool->lock, flags);
270 if (unlikely(new_min_nr <= pool->min_nr)) {
271 /* Raced, other resize will do our work */
272 spin_unlock_irqrestore(&pool->lock, flags);
273 kfree(new_elements);
274 goto out;
275 }
276 memcpy(new_elements, pool->elements,
277 pool->curr_nr * sizeof(*new_elements));
278 kfree(pool->elements);
279 pool->elements = new_elements;
280 pool->min_nr = new_min_nr;
281
282 while (pool->curr_nr < pool->min_nr) {
283 spin_unlock_irqrestore(&pool->lock, flags);
David Rientjes11d83362015-04-14 15:48:21 -0700284 element = pool->alloc(GFP_KERNEL, pool->pool_data);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285 if (!element)
286 goto out;
287 spin_lock_irqsave(&pool->lock, flags);
288 if (pool->curr_nr < pool->min_nr) {
289 add_element(pool, element);
290 } else {
291 spin_unlock_irqrestore(&pool->lock, flags);
292 pool->free(element, pool->pool_data); /* Raced */
293 goto out;
294 }
295 }
296out_unlock:
297 spin_unlock_irqrestore(&pool->lock, flags);
298out:
299 return 0;
300}
301EXPORT_SYMBOL(mempool_resize);
302
303/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 * mempool_alloc - allocate an element from a specific memory pool
305 * @pool: pointer to the memory pool which was allocated via
306 * mempool_create().
307 * @gfp_mask: the usual allocation bitmask.
308 *
Robert P. J. Day72fd4a32007-02-10 01:45:59 -0800309 * this function only sleeps if the alloc_fn() function sleeps or
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 * returns NULL. Note that due to preallocation, this function
311 * *never* fails when called from process contexts. (it might
312 * fail if called from an IRQ context.)
Sebastian Ott8bf8fcb2014-06-04 16:07:00 -0700313 * Note: using __GFP_ZERO is not supported.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314 */
Al Virodd0fc662005-10-07 07:46:04 +0100315void * mempool_alloc(mempool_t *pool, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316{
317 void *element;
318 unsigned long flags;
Benjamin LaHaise01890a42005-06-23 00:10:01 -0700319 wait_queue_t wait;
Al Viro6daa0e22005-10-21 03:18:50 -0400320 gfp_t gfp_temp;
Nick Piggin20a77772005-05-01 08:58:37 -0700321
Sebastian Ott8bf8fcb2014-06-04 16:07:00 -0700322 VM_WARN_ON_ONCE(gfp_mask & __GFP_ZERO);
Nick Piggin20a77772005-05-01 08:58:37 -0700323 might_sleep_if(gfp_mask & __GFP_WAIT);
Nick Pigginb84a35b2005-05-01 08:58:36 -0700324
325 gfp_mask |= __GFP_NOMEMALLOC; /* don't allocate emergency reserves */
326 gfp_mask |= __GFP_NORETRY; /* don't loop in __alloc_pages */
327 gfp_mask |= __GFP_NOWARN; /* failures are OK */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328
Nick Piggin20a77772005-05-01 08:58:37 -0700329 gfp_temp = gfp_mask & ~(__GFP_WAIT|__GFP_IO);
330
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331repeat_alloc:
Nick Piggin20a77772005-05-01 08:58:37 -0700332
333 element = pool->alloc(gfp_temp, pool->pool_data);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334 if (likely(element != NULL))
335 return element;
336
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337 spin_lock_irqsave(&pool->lock, flags);
338 if (likely(pool->curr_nr)) {
339 element = remove_element(pool);
340 spin_unlock_irqrestore(&pool->lock, flags);
Tejun Heo5b990542012-01-10 15:08:23 -0800341 /* paired with rmb in mempool_free(), read comment there */
342 smp_wmb();
Catalin Marinas17411962014-06-06 14:38:19 -0700343 /*
344 * Update the allocation stack trace as this is more useful
345 * for debugging.
346 */
347 kmemleak_update_trace(element);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348 return element;
349 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350
Tejun Heo1ebb7042012-01-10 15:08:28 -0800351 /*
352 * We use gfp mask w/o __GFP_WAIT or IO for the first round. If
353 * alloc failed with that and @pool was empty, retry immediately.
354 */
355 if (gfp_temp != gfp_mask) {
356 spin_unlock_irqrestore(&pool->lock, flags);
357 gfp_temp = gfp_mask;
358 goto repeat_alloc;
359 }
360
361 /* We must not sleep if !__GFP_WAIT */
Tejun Heo5b990542012-01-10 15:08:23 -0800362 if (!(gfp_mask & __GFP_WAIT)) {
363 spin_unlock_irqrestore(&pool->lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 return NULL;
Tejun Heo5b990542012-01-10 15:08:23 -0800365 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366
Tejun Heo5b990542012-01-10 15:08:23 -0800367 /* Let's wait for someone else to return an element to @pool */
Benjamin LaHaise01890a42005-06-23 00:10:01 -0700368 init_wait(&wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369 prepare_to_wait(&pool->wait, &wait, TASK_UNINTERRUPTIBLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370
Tejun Heo5b990542012-01-10 15:08:23 -0800371 spin_unlock_irqrestore(&pool->lock, flags);
372
373 /*
374 * FIXME: this should be io_schedule(). The timeout is there as a
375 * workaround for some DM problems in 2.6.18.
376 */
377 io_schedule_timeout(5*HZ);
378
379 finish_wait(&pool->wait, &wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 goto repeat_alloc;
381}
382EXPORT_SYMBOL(mempool_alloc);
383
384/**
385 * mempool_free - return an element to the pool.
386 * @element: pool element pointer.
387 * @pool: pointer to the memory pool which was allocated via
388 * mempool_create().
389 *
390 * this function only sleeps if the free_fn() function sleeps.
391 */
392void mempool_free(void *element, mempool_t *pool)
393{
394 unsigned long flags;
395
Rusty Russellc80e7a82007-07-15 23:42:00 -0700396 if (unlikely(element == NULL))
397 return;
398
Tejun Heo5b990542012-01-10 15:08:23 -0800399 /*
400 * Paired with the wmb in mempool_alloc(). The preceding read is
401 * for @element and the following @pool->curr_nr. This ensures
402 * that the visible value of @pool->curr_nr is from after the
403 * allocation of @element. This is necessary for fringe cases
404 * where @element was passed to this task without going through
405 * barriers.
406 *
407 * For example, assume @p is %NULL at the beginning and one task
408 * performs "p = mempool_alloc(...);" while another task is doing
409 * "while (!p) cpu_relax(); mempool_free(p, ...);". This function
410 * may end up using curr_nr value which is from before allocation
411 * of @p without the following rmb.
412 */
413 smp_rmb();
414
415 /*
416 * For correctness, we need a test which is guaranteed to trigger
417 * if curr_nr + #allocated == min_nr. Testing curr_nr < min_nr
418 * without locking achieves that and refilling as soon as possible
419 * is desirable.
420 *
421 * Because curr_nr visible here is always a value after the
422 * allocation of @element, any task which decremented curr_nr below
423 * min_nr is guaranteed to see curr_nr < min_nr unless curr_nr gets
424 * incremented to min_nr afterwards. If curr_nr gets incremented
425 * to min_nr after the allocation of @element, the elements
426 * allocated after that are subject to the same guarantee.
427 *
428 * Waiters happen iff curr_nr is 0 and the above guarantee also
429 * ensures that there will be frees which return elements to the
430 * pool waking up the waiters.
431 */
Mikulas Patockaeb9a3c62014-04-07 15:37:35 -0700432 if (unlikely(pool->curr_nr < pool->min_nr)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 spin_lock_irqsave(&pool->lock, flags);
Mikulas Patockaeb9a3c62014-04-07 15:37:35 -0700434 if (likely(pool->curr_nr < pool->min_nr)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435 add_element(pool, element);
436 spin_unlock_irqrestore(&pool->lock, flags);
437 wake_up(&pool->wait);
438 return;
439 }
440 spin_unlock_irqrestore(&pool->lock, flags);
441 }
442 pool->free(element, pool->pool_data);
443}
444EXPORT_SYMBOL(mempool_free);
445
446/*
447 * A commonly used alloc and free fn.
448 */
Al Virodd0fc662005-10-07 07:46:04 +0100449void *mempool_alloc_slab(gfp_t gfp_mask, void *pool_data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450{
Pekka Enbergfcc234f2006-03-22 00:08:13 -0800451 struct kmem_cache *mem = pool_data;
David Rientjese244c9e2015-04-15 16:14:14 -0700452 VM_BUG_ON(mem->ctor);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453 return kmem_cache_alloc(mem, gfp_mask);
454}
455EXPORT_SYMBOL(mempool_alloc_slab);
456
457void mempool_free_slab(void *element, void *pool_data)
458{
Pekka Enbergfcc234f2006-03-22 00:08:13 -0800459 struct kmem_cache *mem = pool_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700460 kmem_cache_free(mem, element);
461}
462EXPORT_SYMBOL(mempool_free_slab);
Matthew Dobson6e0678f2006-03-26 01:37:44 -0800463
464/*
Matthew Dobson53184082006-03-26 01:37:46 -0800465 * A commonly used alloc and free fn that kmalloc/kfrees the amount of memory
Simon Arlott183ff222007-10-20 01:27:18 +0200466 * specified by pool_data
Matthew Dobson53184082006-03-26 01:37:46 -0800467 */
468void *mempool_kmalloc(gfp_t gfp_mask, void *pool_data)
469{
Figo.zhang5e2f89b2009-08-08 21:01:22 +0800470 size_t size = (size_t)pool_data;
Matthew Dobson53184082006-03-26 01:37:46 -0800471 return kmalloc(size, gfp_mask);
472}
473EXPORT_SYMBOL(mempool_kmalloc);
474
475void mempool_kfree(void *element, void *pool_data)
476{
477 kfree(element);
478}
479EXPORT_SYMBOL(mempool_kfree);
480
481/*
Matthew Dobson6e0678f2006-03-26 01:37:44 -0800482 * A simple mempool-backed page allocator that allocates pages
483 * of the order specified by pool_data.
484 */
485void *mempool_alloc_pages(gfp_t gfp_mask, void *pool_data)
486{
487 int order = (int)(long)pool_data;
488 return alloc_pages(gfp_mask, order);
489}
490EXPORT_SYMBOL(mempool_alloc_pages);
491
492void mempool_free_pages(void *element, void *pool_data)
493{
494 int order = (int)(long)pool_data;
495 __free_pages(element, order);
496}
497EXPORT_SYMBOL(mempool_free_pages);