]>
git.proxmox.com Git - mirror_ubuntu-jammy-kernel.git/blob - mm/dmapool.c
4 * Copyright 2001 David Brownell
5 * Copyright 2007 Intel Corporation
6 * Author: Matthew Wilcox <willy@linux.intel.com>
8 * This software may be redistributed and/or modified under the terms of
9 * the GNU General Public License ("GPL") version 2 as published by the
10 * Free Software Foundation.
12 * This allocator returns small blocks of a given size which are DMA-able by
13 * the given device. It uses the dma_alloc_coherent page allocator to get
14 * new pages, then splits them up into blocks of the required size.
15 * Many older drivers still have their own code to do this.
17 * The current design of this allocator is fairly simple. The pool is
18 * represented by the 'struct dma_pool' which keeps a doubly-linked list of
19 * allocated pages. Each page in the page_list is split into blocks of at
20 * least 'size' bytes. Free blocks are tracked in an unsorted singly-linked
21 * list of free blocks within the page. Used blocks aren't tracked, but we
22 * keep a count of how many are currently allocated from each page.
25 #include <linux/device.h>
26 #include <linux/dma-mapping.h>
27 #include <linux/dmapool.h>
28 #include <linux/kernel.h>
29 #include <linux/list.h>
30 #include <linux/export.h>
31 #include <linux/mutex.h>
32 #include <linux/poison.h>
33 #include <linux/sched.h>
34 #include <linux/slab.h>
35 #include <linux/stat.h>
36 #include <linux/spinlock.h>
37 #include <linux/string.h>
38 #include <linux/types.h>
39 #include <linux/wait.h>
41 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB_DEBUG_ON)
42 #define DMAPOOL_DEBUG 1
45 struct dma_pool
{ /* the pool */
46 struct list_head page_list
;
53 struct list_head pools
;
56 struct dma_page
{ /* cacheable header for 'allocation' bytes */
57 struct list_head page_list
;
64 static DEFINE_MUTEX(pools_lock
);
65 static DEFINE_MUTEX(pools_reg_lock
);
68 show_pools(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
73 struct dma_page
*page
;
74 struct dma_pool
*pool
;
79 temp
= scnprintf(next
, size
, "poolinfo - 0.1\n");
83 mutex_lock(&pools_lock
);
84 list_for_each_entry(pool
, &dev
->dma_pools
, pools
) {
88 spin_lock_irq(&pool
->lock
);
89 list_for_each_entry(page
, &pool
->page_list
, page_list
) {
91 blocks
+= page
->in_use
;
93 spin_unlock_irq(&pool
->lock
);
95 /* per-pool info, no real statistics yet */
96 temp
= scnprintf(next
, size
, "%-16s %4u %4Zu %4Zu %2u\n",
98 pages
* (pool
->allocation
/ pool
->size
),
103 mutex_unlock(&pools_lock
);
105 return PAGE_SIZE
- size
;
108 static DEVICE_ATTR(pools
, S_IRUGO
, show_pools
, NULL
);
111 * dma_pool_create - Creates a pool of consistent memory blocks, for dma.
112 * @name: name of pool, for diagnostics
113 * @dev: device that will be doing the DMA
114 * @size: size of the blocks in this pool.
115 * @align: alignment requirement for blocks; must be a power of two
116 * @boundary: returned blocks won't cross this power of two boundary
117 * Context: !in_interrupt()
119 * Returns a dma allocation pool with the requested characteristics, or
120 * null if one can't be created. Given one of these pools, dma_pool_alloc()
121 * may be used to allocate memory. Such memory will all have "consistent"
122 * DMA mappings, accessible by the device and its driver without using
123 * cache flushing primitives. The actual size of blocks allocated may be
124 * larger than requested because of alignment.
126 * If @boundary is nonzero, objects returned from dma_pool_alloc() won't
127 * cross that size boundary. This is useful for devices which have
128 * addressing restrictions on individual DMA transfers, such as not crossing
129 * boundaries of 4KBytes.
131 struct dma_pool
*dma_pool_create(const char *name
, struct device
*dev
,
132 size_t size
, size_t align
, size_t boundary
)
134 struct dma_pool
*retval
;
140 else if (align
& (align
- 1))
148 if ((size
% align
) != 0)
149 size
= ALIGN(size
, align
);
151 allocation
= max_t(size_t, size
, PAGE_SIZE
);
154 boundary
= allocation
;
155 else if ((boundary
< size
) || (boundary
& (boundary
- 1)))
158 retval
= kmalloc_node(sizeof(*retval
), GFP_KERNEL
, dev_to_node(dev
));
162 strlcpy(retval
->name
, name
, sizeof(retval
->name
));
166 INIT_LIST_HEAD(&retval
->page_list
);
167 spin_lock_init(&retval
->lock
);
169 retval
->boundary
= boundary
;
170 retval
->allocation
= allocation
;
172 INIT_LIST_HEAD(&retval
->pools
);
175 * pools_lock ensures that the ->dma_pools list does not get corrupted.
176 * pools_reg_lock ensures that there is not a race between
177 * dma_pool_create() and dma_pool_destroy() or within dma_pool_create()
178 * when the first invocation of dma_pool_create() failed on
179 * device_create_file() and the second assumes that it has been done (I
180 * know it is a short window).
182 mutex_lock(&pools_reg_lock
);
183 mutex_lock(&pools_lock
);
184 if (list_empty(&dev
->dma_pools
))
186 list_add(&retval
->pools
, &dev
->dma_pools
);
187 mutex_unlock(&pools_lock
);
191 err
= device_create_file(dev
, &dev_attr_pools
);
193 mutex_lock(&pools_lock
);
194 list_del(&retval
->pools
);
195 mutex_unlock(&pools_lock
);
196 mutex_unlock(&pools_reg_lock
);
201 mutex_unlock(&pools_reg_lock
);
204 EXPORT_SYMBOL(dma_pool_create
);
206 static void pool_initialise_page(struct dma_pool
*pool
, struct dma_page
*page
)
208 unsigned int offset
= 0;
209 unsigned int next_boundary
= pool
->boundary
;
212 unsigned int next
= offset
+ pool
->size
;
213 if (unlikely((next
+ pool
->size
) >= next_boundary
)) {
214 next
= next_boundary
;
215 next_boundary
+= pool
->boundary
;
217 *(int *)(page
->vaddr
+ offset
) = next
;
219 } while (offset
< pool
->allocation
);
222 static struct dma_page
*pool_alloc_page(struct dma_pool
*pool
, gfp_t mem_flags
)
224 struct dma_page
*page
;
226 page
= kmalloc(sizeof(*page
), mem_flags
);
229 page
->vaddr
= dma_alloc_coherent(pool
->dev
, pool
->allocation
,
230 &page
->dma
, mem_flags
);
233 memset(page
->vaddr
, POOL_POISON_FREED
, pool
->allocation
);
235 pool_initialise_page(pool
, page
);
245 static inline int is_page_busy(struct dma_page
*page
)
247 return page
->in_use
!= 0;
250 static void pool_free_page(struct dma_pool
*pool
, struct dma_page
*page
)
252 dma_addr_t dma
= page
->dma
;
255 memset(page
->vaddr
, POOL_POISON_FREED
, pool
->allocation
);
257 dma_free_coherent(pool
->dev
, pool
->allocation
, page
->vaddr
, dma
);
258 list_del(&page
->page_list
);
263 * dma_pool_destroy - destroys a pool of dma memory blocks.
264 * @pool: dma pool that will be destroyed
265 * Context: !in_interrupt()
267 * Caller guarantees that no more memory from the pool is in use,
268 * and that nothing will try to use the pool after this call.
270 void dma_pool_destroy(struct dma_pool
*pool
)
274 mutex_lock(&pools_reg_lock
);
275 mutex_lock(&pools_lock
);
276 list_del(&pool
->pools
);
277 if (pool
->dev
&& list_empty(&pool
->dev
->dma_pools
))
279 mutex_unlock(&pools_lock
);
281 device_remove_file(pool
->dev
, &dev_attr_pools
);
282 mutex_unlock(&pools_reg_lock
);
284 while (!list_empty(&pool
->page_list
)) {
285 struct dma_page
*page
;
286 page
= list_entry(pool
->page_list
.next
,
287 struct dma_page
, page_list
);
288 if (is_page_busy(page
)) {
291 "dma_pool_destroy %s, %p busy\n",
292 pool
->name
, page
->vaddr
);
295 "dma_pool_destroy %s, %p busy\n",
296 pool
->name
, page
->vaddr
);
297 /* leak the still-in-use consistent memory */
298 list_del(&page
->page_list
);
301 pool_free_page(pool
, page
);
306 EXPORT_SYMBOL(dma_pool_destroy
);
309 * dma_pool_alloc - get a block of consistent memory
310 * @pool: dma pool that will produce the block
311 * @mem_flags: GFP_* bitmask
312 * @handle: pointer to dma address of block
314 * This returns the kernel virtual address of a currently unused block,
315 * and reports its dma address through the handle.
316 * If such a memory block can't be allocated, %NULL is returned.
318 void *dma_pool_alloc(struct dma_pool
*pool
, gfp_t mem_flags
,
322 struct dma_page
*page
;
326 might_sleep_if(mem_flags
& __GFP_WAIT
);
328 spin_lock_irqsave(&pool
->lock
, flags
);
329 list_for_each_entry(page
, &pool
->page_list
, page_list
) {
330 if (page
->offset
< pool
->allocation
)
334 /* pool_alloc_page() might sleep, so temporarily drop &pool->lock */
335 spin_unlock_irqrestore(&pool
->lock
, flags
);
337 page
= pool_alloc_page(pool
, mem_flags
);
341 spin_lock_irqsave(&pool
->lock
, flags
);
343 list_add(&page
->page_list
, &pool
->page_list
);
346 offset
= page
->offset
;
347 page
->offset
= *(int *)(page
->vaddr
+ offset
);
348 retval
= offset
+ page
->vaddr
;
349 *handle
= offset
+ page
->dma
;
354 /* page->offset is stored in first 4 bytes */
355 for (i
= sizeof(page
->offset
); i
< pool
->size
; i
++) {
356 if (data
[i
] == POOL_POISON_FREED
)
360 "dma_pool_alloc %s, %p (corrupted)\n",
363 pr_err("dma_pool_alloc %s, %p (corrupted)\n",
367 * Dump the first 4 bytes even if they are not
370 print_hex_dump(KERN_ERR
, "", DUMP_PREFIX_OFFSET
, 16, 1,
371 data
, pool
->size
, 1);
375 memset(retval
, POOL_POISON_ALLOCATED
, pool
->size
);
377 spin_unlock_irqrestore(&pool
->lock
, flags
);
380 EXPORT_SYMBOL(dma_pool_alloc
);
382 static struct dma_page
*pool_find_page(struct dma_pool
*pool
, dma_addr_t dma
)
384 struct dma_page
*page
;
386 list_for_each_entry(page
, &pool
->page_list
, page_list
) {
389 if (dma
< (page
->dma
+ pool
->allocation
))
396 * dma_pool_free - put block back into dma pool
397 * @pool: the dma pool holding the block
398 * @vaddr: virtual address of block
399 * @dma: dma address of block
401 * Caller promises neither device nor driver will again touch this block
402 * unless it is first re-allocated.
404 void dma_pool_free(struct dma_pool
*pool
, void *vaddr
, dma_addr_t dma
)
406 struct dma_page
*page
;
410 spin_lock_irqsave(&pool
->lock
, flags
);
411 page
= pool_find_page(pool
, dma
);
413 spin_unlock_irqrestore(&pool
->lock
, flags
);
416 "dma_pool_free %s, %p/%lx (bad dma)\n",
417 pool
->name
, vaddr
, (unsigned long)dma
);
419 printk(KERN_ERR
"dma_pool_free %s, %p/%lx (bad dma)\n",
420 pool
->name
, vaddr
, (unsigned long)dma
);
424 offset
= vaddr
- page
->vaddr
;
426 if ((dma
- page
->dma
) != offset
) {
427 spin_unlock_irqrestore(&pool
->lock
, flags
);
430 "dma_pool_free %s, %p (bad vaddr)/%Lx\n",
431 pool
->name
, vaddr
, (unsigned long long)dma
);
434 "dma_pool_free %s, %p (bad vaddr)/%Lx\n",
435 pool
->name
, vaddr
, (unsigned long long)dma
);
439 unsigned int chain
= page
->offset
;
440 while (chain
< pool
->allocation
) {
441 if (chain
!= offset
) {
442 chain
= *(int *)(page
->vaddr
+ chain
);
445 spin_unlock_irqrestore(&pool
->lock
, flags
);
447 dev_err(pool
->dev
, "dma_pool_free %s, dma %Lx "
448 "already free\n", pool
->name
,
449 (unsigned long long)dma
);
451 printk(KERN_ERR
"dma_pool_free %s, dma %Lx "
452 "already free\n", pool
->name
,
453 (unsigned long long)dma
);
457 memset(vaddr
, POOL_POISON_FREED
, pool
->size
);
461 *(int *)vaddr
= page
->offset
;
462 page
->offset
= offset
;
464 * Resist a temptation to do
465 * if (!is_page_busy(page)) pool_free_page(pool, page);
466 * Better have a few empty pages hang around.
468 spin_unlock_irqrestore(&pool
->lock
, flags
);
470 EXPORT_SYMBOL(dma_pool_free
);
475 static void dmam_pool_release(struct device
*dev
, void *res
)
477 struct dma_pool
*pool
= *(struct dma_pool
**)res
;
479 dma_pool_destroy(pool
);
482 static int dmam_pool_match(struct device
*dev
, void *res
, void *match_data
)
484 return *(struct dma_pool
**)res
== match_data
;
488 * dmam_pool_create - Managed dma_pool_create()
489 * @name: name of pool, for diagnostics
490 * @dev: device that will be doing the DMA
491 * @size: size of the blocks in this pool.
492 * @align: alignment requirement for blocks; must be a power of two
493 * @allocation: returned blocks won't cross this boundary (or zero)
495 * Managed dma_pool_create(). DMA pool created with this function is
496 * automatically destroyed on driver detach.
498 struct dma_pool
*dmam_pool_create(const char *name
, struct device
*dev
,
499 size_t size
, size_t align
, size_t allocation
)
501 struct dma_pool
**ptr
, *pool
;
503 ptr
= devres_alloc(dmam_pool_release
, sizeof(*ptr
), GFP_KERNEL
);
507 pool
= *ptr
= dma_pool_create(name
, dev
, size
, align
, allocation
);
509 devres_add(dev
, ptr
);
515 EXPORT_SYMBOL(dmam_pool_create
);
518 * dmam_pool_destroy - Managed dma_pool_destroy()
519 * @pool: dma pool that will be destroyed
521 * Managed dma_pool_destroy().
523 void dmam_pool_destroy(struct dma_pool
*pool
)
525 struct device
*dev
= pool
->dev
;
527 WARN_ON(devres_release(dev
, dmam_pool_release
, dmam_pool_match
, pool
));
529 EXPORT_SYMBOL(dmam_pool_destroy
);