// SPDX-License-Identifier: GPL-2.0-only/* * DMA Pool allocator * * Copyright 2001 David Brownell * Copyright 2007 Intel Corporation * Author: Matthew Wilcox <willy@linux.intel.com> * * This allocator returns small blocks of a given size which are DMA-able by * the given device. It uses the dma_alloc_coherent page allocator to get * new pages, then splits them up into blocks of the required size. * Many older drivers still have their own code to do this. * * The current design of this allocator is fairly simple. The pool is * represented by the 'struct dma_pool' which keeps a doubly-linked list of * allocated pages. Each page in the page_list is split into blocks of at * least 'size' bytes. Free blocks are tracked in an unsorted singly-linked * list of free blocks across all pages. Used blocks aren't tracked, but we * keep a count of how many are currently allocated from each page. */ #include <linux/device.h>#include <linux/dma-mapping.h>#include <linux/dmapool.h>#include <linux/kernel.h>#include <linux/list.h>#include <linux/export.h>#include <linux/mutex.h>#include <linux/poison.h>#include <linux/sched.h>#include <linux/sched/mm.h>#include <linux/slab.h>#include <linux/stat.h>#include <linux/spinlock.h>#include <linux/string.h>#include <linux/types.h>#include <linux/wait.h> #ifdef CONFIG_SLUB_DEBUG_ON#define DMAPOOL_DEBUG 1#endif struct dma_block { struct dma_block *next_block; dma_addr_t dma;}; struct dma_pool { /* the pool */ struct list_head page_list; spinlock_t lock; struct dma_block *next_block; size_t nr_blocks; size_t nr_active; size_t nr_pages; struct device *dev; unsigned int size; unsigned int allocation; unsigned int boundary; int node; char name[32]; struct list_head pools;}; struct dma_page { /* cacheable header for 'allocation' bytes */ struct list_head page_list; void *vaddr; dma_addr_t dma;}; static DEFINE_MUTEX(pools_lock);static DEFINE_MUTEX(pools_reg_lock); static ssize_t pools_show(struct device *dev, struct device_attribute *attr, char *buf){ struct dma_pool *pool; unsigned size; size = sysfs_emit(buf, "poolinfo - 0.1\n"); mutex_lock(&pools_lock); list_for_each_entry(pool, &dev->dma_pools, pools) { /* per-pool info, no real statistics yet */ size += sysfs_emit_at(buf, size, "%-16s %4zu %4zu %4u %2zu\n", pool->name, pool->nr_active, pool->nr_blocks, pool->size, pool->nr_pages); } mutex_unlock(&pools_lock); return size;} static DEVICE_ATTR_RO(pools); #ifdef DMAPOOL_DEBUGstatic void pool_check_block(struct dma_pool *pool, struct dma_block *block, gfp_t mem_flags){ u8 *data = (void *)block; int i; for (i = sizeof(struct dma_block); i < pool->size; i++) { if (data[i] == POOL_POISON_FREED) continue; dev_err(pool->dev, "%s %s, %p (corrupted)\n", __func__, pool->name, block); /* * Dump the first 4 bytes even if they are not * POOL_POISON_FREED */ print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1, data, pool->size, 1); break; } if (!want_init_on_alloc(mem_flags)) memset(block, POOL_POISON_ALLOCATED, pool->size);} static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma){ struct dma_page *page; list_for_each_entry(page, &pool->page_list, page_list) { if (dma < page->dma) continue; if ((dma - page->dma) < pool->allocation) return page; } return NULL;} static bool pool_block_err(struct dma_pool *pool, void *vaddr, dma_addr_t dma){ struct dma_block *block = pool->next_block; struct dma_page *page; page = pool_find_page(pool, dma); if (!page) { dev_err(pool->dev, "%s %s, %p/%pad (bad dma)\n", __func__, pool->name, vaddr, &dma); return true; } while (block) { if (block != vaddr) { block = block->next_block; continue; } dev_err(pool->dev, "%s %s, dma %pad already free\n", __func__, pool->name, &dma); return true; } memset(vaddr, POOL_POISON_FREED, pool->size); return false;} static void pool_init_page(struct dma_pool *pool, struct dma_page *page){ memset(page->vaddr, POOL_POISON_FREED, pool->allocation);}#elsestatic void pool_check_block(struct dma_pool *pool, struct dma_block *block, gfp_t mem_flags){} static bool pool_block_err(struct dma_pool *pool, void *vaddr, dma_addr_t dma){ if (want_init_on_free()) memset(vaddr, 0, pool->size); return false;} static void pool_init_page(struct dma_pool *pool, struct dma_page *page){}#endif static struct dma_block *pool_block_pop(struct dma_pool *pool){ struct dma_block *block = pool->next_block; if (block) { pool->next_block = block->next_block; pool->nr_active++; } return block;} static void pool_block_push(struct dma_pool *pool, struct dma_block *block, dma_addr_t dma){ block->dma = dma; block->next_block = pool->next_block; pool->next_block = block;} /** * dma_pool_create_node - Creates a pool of coherent DMA memory blocks. * @name: name of pool, for diagnostics * @dev: device that will be doing the DMA * @size: size of the blocks in this pool. * @align: alignment requirement for blocks; must be a power of two * @boundary: returned blocks won't cross this power of two boundary * @node: optional NUMA node to allocate structs 'dma_pool' and 'dma_page' on * Context: not in_interrupt() * * Given one of these pools, dma_pool_alloc() * may be used to allocate memory. Such memory will all have coherent * DMA mappings, accessible by the device and its driver without using * cache flushing primitives. The actual size of blocks allocated may be * larger than requested because of alignment. * * If @boundary is nonzero, objects returned from dma_pool_alloc() won't * cross that size boundary. This is useful for devices which have * addressing restrictions on individual DMA transfers, such as not crossing * boundaries of 4KBytes. * * Return: a dma allocation pool with the requested characteristics, or * %NULL if one can't be created. */struct dma_pool *dma_pool_create_node(const char *name, struct device *dev, size_t size, size_t align, size_t boundary, int node){ struct dma_pool *retval; size_t allocation; bool empty; if (!dev) return NULL; if (align == 0) align = 1; else if (align & (align - 1)) return NULL; if (size == 0 || size > INT_MAX) return NULL; if (size < sizeof(struct dma_block)) size = sizeof(struct dma_block); size = ALIGN(size, align); allocation = max_t(size_t, size, PAGE_SIZE); if (!boundary) boundary = allocation; else if ((boundary < size) || (boundary & (boundary - 1))) return NULL; boundary = min(boundary, allocation); retval = kzalloc_node(sizeof(*retval), GFP_KERNEL, node); if (!retval) return retval; strscpy(retval->name, name, sizeof(retval->name)); retval->dev = dev; INIT_LIST_HEAD(&retval->page_list); spin_lock_init(&retval->lock); retval->size = size; retval->boundary = boundary; retval->allocation = allocation; retval->node = node; INIT_LIST_HEAD(&retval->pools); /* * pools_lock ensures that the ->dma_pools list does not get corrupted. * pools_reg_lock ensures that there is not a race between * dma_pool_create() and dma_pool_destroy() or within dma_pool_create() * when the first invocation of dma_pool_create() failed on * device_create_file() and the second assumes that it has been done (I * know it is a short window). */ mutex_lock(&pools_reg_lock); mutex_lock(&pools_lock); empty = list_empty(&dev->dma_pools); list_add(&retval->pools, &dev->dma_pools); mutex_unlock(&pools_lock); if (empty) { int err; err = device_create_file(dev, &dev_attr_pools); if (err) { mutex_lock(&pools_lock); list_del(&retval->pools); mutex_unlock(&pools_lock); mutex_unlock(&pools_reg_lock); kfree(retval); return NULL; } } mutex_unlock(&pools_reg_lock); return retval;}EXPORT_SYMBOL(dma_pool_create_node); static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page){ unsigned int next_boundary = pool->boundary, offset = 0; struct dma_block *block, *first = NULL, *last = NULL; pool_init_page(pool, page); while (offset + pool->size <= pool->allocation) { if (offset + pool->size > next_boundary) { offset = next_boundary; next_boundary += pool->boundary; continue; } block = page->vaddr + offset; block->dma = page->dma + offset; block->next_block = NULL; if (last) last->next_block = block; else first = block; last = block; offset += pool->size; pool->nr_blocks++; } last->next_block = pool->next_block; pool->next_block = first; list_add(&page->page_list, &pool->page_list); pool->nr_pages++;} static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags){ struct dma_page *page; page = kmalloc_node(sizeof(*page), mem_flags, pool->node); if (!page) return NULL; page->vaddr = dma_alloc_coherent(pool->dev, pool->allocation, &page->dma, mem_flags); if (!page->vaddr) { kfree(page); return NULL; } return page;} /** * dma_pool_destroy - destroys a pool of dma memory blocks. * @pool: dma pool that will be destroyed * Context: !in_interrupt() * * Caller guarantees that no more memory from the pool is in use, * and that nothing will try to use the pool after this call. */void dma_pool_destroy(struct dma_pool *pool){ struct dma_page *page, *tmp; bool empty, busy = false; if (unlikely(!pool)) return; mutex_lock(&pools_reg_lock); mutex_lock(&pools_lock); list_del(&pool->pools); empty = list_empty(&pool->dev->dma_pools); mutex_unlock(&pools_lock); if (empty) device_remove_file(pool->dev, &dev_attr_pools); mutex_unlock(&pools_reg_lock); if (pool->nr_active) { dev_err(pool->dev, "%s %s busy\n", __func__, pool->name); busy = true; } list_for_each_entry_safe(page, tmp, &pool->page_list, page_list) { if (!busy) dma_free_coherent(pool->dev, pool->allocation, page->vaddr, page->dma); list_del(&page->page_list); kfree(page); } kfree(pool);}EXPORT_SYMBOL(dma_pool_destroy); /** * dma_pool_alloc - get a block of coherent memory * @pool: dma pool that will produce the block * @mem_flags: GFP_* bitmask * @handle: pointer to dma address of block * * Return: the kernel virtual address of a currently unused block, * and reports its dma address through the handle. * If such a memory block can't be allocated, %NULL is returned. */void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags, dma_addr_t *handle){ struct dma_block *block; struct dma_page *page; unsigned long flags; might_alloc(mem_flags); spin_lock_irqsave(&pool->lock, flags); block = pool_block_pop(pool); if (!block) { /* * pool_alloc_page() might sleep, so temporarily drop * &pool->lock */ spin_unlock_irqrestore(&pool->lock, flags); page = pool_alloc_page(pool, mem_flags & (~__GFP_ZERO)); if (!page) return NULL; spin_lock_irqsave(&pool->lock, flags); pool_initialise_page(pool, page); block = pool_block_pop(pool); } spin_unlock_irqrestore(&pool->lock, flags); *handle = block->dma; pool_check_block(pool, block, mem_flags); if (want_init_on_alloc(mem_flags)) memset(block, 0, pool->size); return block;}EXPORT_SYMBOL(dma_pool_alloc); /** * dma_pool_free - put block back into dma pool * @pool: the dma pool holding the block * @vaddr: virtual address of block * @dma: dma address of block * * Caller promises neither device nor driver will again touch this block * unless it is first re-allocated. */void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma){ struct dma_block *block = vaddr; unsigned long flags; spin_lock_irqsave(&pool->lock, flags); if (!pool_block_err(pool, vaddr, dma)) { pool_block_push(pool, block, dma); pool->nr_active--; } spin_unlock_irqrestore(&pool->lock, flags);}EXPORT_SYMBOL(dma_pool_free); /* * Managed DMA pool */static void dmam_pool_release(struct device *dev, void *res){ struct dma_pool *pool = *(struct dma_pool **)res; dma_pool_destroy(pool);} static int dmam_pool_match(struct device *dev, void *res, void *match_data){ return *(struct dma_pool **)res == match_data;} /** * dmam_pool_create - Managed dma_pool_create() * @name: name of pool, for diagnostics * @dev: device that will be doing the DMA * @size: size of the blocks in this pool. * @align: alignment requirement for blocks; must be a power of two * @allocation: returned blocks won't cross this boundary (or zero) * * Managed dma_pool_create(). DMA pool created with this function is * automatically destroyed on driver detach. * * Return: a managed dma allocation pool with the requested * characteristics, or %NULL if one can't be created. */struct dma_pool *dmam_pool_create(const char *name, struct device *dev, size_t size, size_t align, size_t allocation){ struct dma_pool **ptr, *pool; Lines 1–500 of 527. Load more
// SPDX-License-Identifier: GPL-2.0-only /* * DMA Pool allocator * * Copyright 2001 David Brownell * Copyright 2007 Intel Corporation * Author: Matthew Wilcox <willy@linux.intel.com> * * This allocator returns small blocks of a given size which are DMA-able by * the given device. It uses the dma_alloc_coherent page allocator to get * new pages, then splits them up into blocks of the required size. * Many older drivers still have their own code to do this. * * The current design of this allocator is fairly simple. The pool is * represented by the 'struct dma_pool' which keeps a doubly-linked list of * allocated pages. Each page in the page_list is split into blocks of at * least 'size' bytes. Free blocks are tracked in an unsorted singly-linked * list of free blocks across all pages. Used blocks aren't tracked, but we * keep a count of how many are currently allocated from each page. */ #include <linux/device.h> #include <linux/dma-mapping.h> #include <linux/dmapool.h> #include <linux/kernel.h> #include <linux/list.h> #include <linux/export.h> #include <linux/mutex.h> #include <linux/poison.h> #include <linux/sched.h> #include <linux/sched/mm.h> #include <linux/slab.h> #include <linux/stat.h> #include <linux/spinlock.h> #include <linux/string.h> #include <linux/types.h> #include <linux/wait.h> #ifdef CONFIG_SLUB_DEBUG_ON #define DMAPOOL_DEBUG 1 #endif struct dma_block { struct dma_block *next_block; dma_addr_t dma; }; struct dma_pool { /* the pool */ struct list_head page_list; spinlock_t lock; struct dma_block *next_block; size_t nr_blocks; size_t nr_active; size_t nr_pages; struct device *dev; unsigned int size; unsigned int allocation; unsigned int boundary; int node; char name[32]; struct list_head pools; }; struct dma_page { /* cacheable header for 'allocation' bytes */ struct list_head page_list; void *vaddr; dma_addr_t dma; }; static DEFINE_MUTEX(pools_lock); static DEFINE_MUTEX(pools_reg_lock); static ssize_t pools_show(struct device *dev, struct device_attribute *attr, char *buf) { struct dma_pool *pool; unsigned size; size = sysfs_emit(buf, "poolinfo - 0.1\n"); mutex_lock(&pools_lock); list_for_each_entry(pool, &dev->dma_pools, pools) { /* per-pool info, no real statistics yet */ size += sysfs_emit_at(buf, size, "%-16s %4zu %4zu %4u %2zu\n", pool->name, pool->nr_active, pool->nr_blocks, pool->size, pool->nr_pages); } mutex_unlock(&pools_lock); return size; } static DEVICE_ATTR_RO(pools); #ifdef DMAPOOL_DEBUG static void pool_check_block(struct dma_pool *pool, struct dma_block *block, gfp_t mem_flags) { u8 *data = (void *)block; int i; for (i = sizeof(struct dma_block); i < pool->size; i++) { if (data[i] == POOL_POISON_FREED) continue; dev_err(pool->dev, "%s %s, %p (corrupted)\n", __func__, pool->name, block); /* * Dump the first 4 bytes even if they are not * POOL_POISON_FREED */ print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1, data, pool->size, 1); break; } if (!want_init_on_alloc(mem_flags)) memset(block, POOL_POISON_ALLOCATED, pool->size); } static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma) { struct dma_page *page; list_for_each_entry(page, &pool->page_list, page_list) { if (dma < page->dma) continue; if ((dma - page->dma) < pool->allocation) return page; } return NULL; } static bool pool_block_err(struct dma_pool *pool, void *vaddr, dma_addr_t dma) { struct dma_block *block = pool->next_block; struct dma_page *page; page = pool_find_page(pool, dma); if (!page) { dev_err(pool->dev, "%s %s, %p/%pad (bad dma)\n", __func__, pool->name, vaddr, &dma); return true; } while (block) { if (block != vaddr) { block = block->next_block; continue; } dev_err(pool->dev, "%s %s, dma %pad already free\n", __func__, pool->name, &dma); return true; } memset(vaddr, POOL_POISON_FREED, pool->size); return false; } static void pool_init_page(struct dma_pool *pool, struct dma_page *page) { memset(page->vaddr, POOL_POISON_FREED, pool->allocation); } #else static void pool_check_block(struct dma_pool *pool, struct dma_block *block, gfp_t mem_flags) { } static bool pool_block_err(struct dma_pool *pool, void *vaddr, dma_addr_t dma) { if (want_init_on_free()) memset(vaddr, 0, pool->size); return false; } static void pool_init_page(struct dma_pool *pool, struct dma_page *page) { } #endif static struct dma_block *pool_block_pop(struct dma_pool *pool) { struct dma_block *block = pool->next_block; if (block) { pool->next_block = block->next_block; pool->nr_active++; } return block; } static void pool_block_push(struct dma_pool *pool, struct dma_block *block, dma_addr_t dma) { block->dma = dma; block->next_block = pool->next_block; pool->next_block = block; } /** * dma_pool_create_node - Creates a pool of coherent DMA memory blocks. * @name: name of pool, for diagnostics * @dev: device that will be doing the DMA * @size: size of the blocks in this pool. * @align: alignment requirement for blocks; must be a power of two * @boundary: returned blocks won't cross this power of two boundary * @node: optional NUMA node to allocate structs 'dma_pool' and 'dma_page' on * Context: not in_interrupt() * * Given one of these pools, dma_pool_alloc() * may be used to allocate memory. Such memory will all have coherent * DMA mappings, accessible by the device and its driver without using * cache flushing primitives. The actual size of blocks allocated may be * larger than requested because of alignment. * * If @boundary is nonzero, objects returned from dma_pool_alloc() won't * cross that size boundary. This is useful for devices which have * addressing restrictions on individual DMA transfers, such as not crossing * boundaries of 4KBytes. * * Return: a dma allocation pool with the requested characteristics, or * %NULL if one can't be created. */ struct dma_pool *dma_pool_create_node(const char *name, struct device *dev, size_t size, size_t align, size_t boundary, int node) { struct dma_pool *retval; size_t allocation; bool empty; if (!dev) return NULL; if (align == 0) align = 1; else if (align & (align - 1)) return NULL; if (size == 0 || size > INT_MAX) return NULL; if (size < sizeof(struct dma_block)) size = sizeof(struct dma_block); size = ALIGN(size, align); allocation = max_t(size_t, size, PAGE_SIZE); if (!boundary) boundary = allocation; else if ((boundary < size) || (boundary & (boundary - 1))) return NULL; boundary = min(boundary, allocation); retval = kzalloc_node(sizeof(*retval), GFP_KERNEL, node); if (!retval) return retval; strscpy(retval->name, name, sizeof(retval->name)); retval->dev = dev; INIT_LIST_HEAD(&retval->page_list); spin_lock_init(&retval->lock); retval->size = size; retval->boundary = boundary; retval->allocation = allocation; retval->node = node; INIT_LIST_HEAD(&retval->pools); /* * pools_lock ensures that the ->dma_pools list does not get corrupted. * pools_reg_lock ensures that there is not a race between * dma_pool_create() and dma_pool_destroy() or within dma_pool_create() * when the first invocation of dma_pool_create() failed on * device_create_file() and the second assumes that it has been done (I * know it is a short window). */ mutex_lock(&pools_reg_lock); mutex_lock(&pools_lock); empty = list_empty(&dev->dma_pools); list_add(&retval->pools, &dev->dma_pools); mutex_unlock(&pools_lock); if (empty) { int err; err = device_create_file(dev, &dev_attr_pools); if (err) { mutex_lock(&pools_lock); list_del(&retval->pools); mutex_unlock(&pools_lock); mutex_unlock(&pools_reg_lock); kfree(retval); return NULL; } } mutex_unlock(&pools_reg_lock); return retval; } EXPORT_SYMBOL(dma_pool_create_node); static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page) { unsigned int next_boundary = pool->boundary, offset = 0; struct dma_block *block, *first = NULL, *last = NULL; pool_init_page(pool, page); while (offset + pool->size <= pool->allocation) { if (offset + pool->size > next_boundary) { offset = next_boundary; next_boundary += pool->boundary; continue; } block = page->vaddr + offset; block->dma = page->dma + offset; block->next_block = NULL; if (last) last->next_block = block; else first = block; last = block; offset += pool->size; pool->nr_blocks++; } last->next_block = pool->next_block; pool->next_block = first; list_add(&page->page_list, &pool->page_list); pool->nr_pages++; } static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags) { struct dma_page *page; page = kmalloc_node(sizeof(*page), mem_flags, pool->node); if (!page) return NULL; page->vaddr = dma_alloc_coherent(pool->dev, pool->allocation, &page->dma, mem_flags); if (!page->vaddr) { kfree(page); return NULL; } return page; } /** * dma_pool_destroy - destroys a pool of dma memory blocks. * @pool: dma pool that will be destroyed * Context: !in_interrupt() * * Caller guarantees that no more memory from the pool is in use, * and that nothing will try to use the pool after this call. */ void dma_pool_destroy(struct dma_pool *pool) { struct dma_page *page, *tmp; bool empty, busy = false; if (unlikely(!pool)) return; mutex_lock(&pools_reg_lock); mutex_lock(&pools_lock); list_del(&pool->pools); empty = list_empty(&pool->dev->dma_pools); mutex_unlock(&pools_lock); if (empty) device_remove_file(pool->dev, &dev_attr_pools); mutex_unlock(&pools_reg_lock); if (pool->nr_active) { dev_err(pool->dev, "%s %s busy\n", __func__, pool->name); busy = true; } list_for_each_entry_safe(page, tmp, &pool->page_list, page_list) { if (!busy) dma_free_coherent(pool->dev, pool->allocation, page->vaddr, page->dma); list_del(&page->page_list); kfree(page); } kfree(pool); } EXPORT_SYMBOL(dma_pool_destroy); /** * dma_pool_alloc - get a block of coherent memory * @pool: dma pool that will produce the block * @mem_flags: GFP_* bitmask * @handle: pointer to dma address of block * * Return: the kernel virtual address of a currently unused block, * and reports its dma address through the handle. * If such a memory block can't be allocated, %NULL is returned. */ void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags, dma_addr_t *handle) { struct dma_block *block; struct dma_page *page; unsigned long flags; might_alloc(mem_flags); spin_lock_irqsave(&pool->lock, flags); block = pool_block_pop(pool); if (!block) { /* * pool_alloc_page() might sleep, so temporarily drop * &pool->lock */ spin_unlock_irqrestore(&pool->lock, flags); page = pool_alloc_page(pool, mem_flags & (~__GFP_ZERO)); if (!page) return NULL; spin_lock_irqsave(&pool->lock, flags); pool_initialise_page(pool, page); block = pool_block_pop(pool); } spin_unlock_irqrestore(&pool->lock, flags); *handle = block->dma; pool_check_block(pool, block, mem_flags); if (want_init_on_alloc(mem_flags)) memset(block, 0, pool->size); return block; } EXPORT_SYMBOL(dma_pool_alloc); /** * dma_pool_free - put block back into dma pool * @pool: the dma pool holding the block * @vaddr: virtual address of block * @dma: dma address of block * * Caller promises neither device nor driver will again touch this block * unless it is first re-allocated. */ void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma) { struct dma_block *block = vaddr; unsigned long flags; spin_lock_irqsave(&pool->lock, flags); if (!pool_block_err(pool, vaddr, dma)) { pool_block_push(pool, block, dma); pool->nr_active--; } spin_unlock_irqrestore(&pool->lock, flags); } EXPORT_SYMBOL(dma_pool_free); /* * Managed DMA pool */ static void dmam_pool_release(struct device *dev, void *res) { struct dma_pool *pool = *(struct dma_pool **)res; dma_pool_destroy(pool); } static int dmam_pool_match(struct device *dev, void *res, void *match_data) { return *(struct dma_pool **)res == match_data; } /** * dmam_pool_create - Managed dma_pool_create() * @name: name of pool, for diagnostics * @dev: device that will be doing the DMA * @size: size of the blocks in this pool. * @align: alignment requirement for blocks; must be a power of two * @allocation: returned blocks won't cross this boundary (or zero) * * Managed dma_pool_create(). DMA pool created with this function is * automatically destroyed on driver detach. * * Return: a managed dma allocation pool with the requested * characteristics, or %NULL if one can't be created. */ struct dma_pool *dmam_pool_create(const char *name, struct device *dev, size_t size, size_t align, size_t allocation) { struct dma_pool **ptr, *pool;