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authorLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-05 19:05:48 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-05 19:05:48 -0800
commitb297d520b9af536d5580ac505dd316be4cf5560c (patch)
treea8f292b308c166ebd383b73fa09538775352c874
parentc773633916c66f8362ca01983d97bd33e35b743f (diff)
parente34f44b3517fe545f7fd45a8c2f6ee1e5e4432d3 (diff)
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Merge branch 'dmapool' of git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc
* 'dmapool' of git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc: pool: Improve memory usage for devices which can't cross boundaries Change dmapool free block management dmapool: Tidy up includes and add comments dmapool: Validate parameters to dma_pool_create Avoid taking waitqueue lock in dmapool dmapool: Fix style problems Move dmapool.c to mm/ directory
-rw-r--r--drivers/base/Makefile2
-rw-r--r--drivers/base/dmapool.c481
-rw-r--r--mm/Makefile1
-rw-r--r--mm/dmapool.c500
4 files changed, 502 insertions, 482 deletions
diff --git a/drivers/base/Makefile b/drivers/base/Makefile
index 63e09c015ca..c66637392bb 100644
--- a/drivers/base/Makefile
+++ b/drivers/base/Makefile
@@ -5,7 +5,7 @@ obj-y := core.o sys.o bus.o dd.o \
cpu.o firmware.o init.o map.o devres.o \
attribute_container.o transport_class.o
obj-y += power/
-obj-$(CONFIG_HAS_DMA) += dma-mapping.o dmapool.o
+obj-$(CONFIG_HAS_DMA) += dma-mapping.o
obj-$(CONFIG_ISA) += isa.o
obj-$(CONFIG_FW_LOADER) += firmware_class.o
obj-$(CONFIG_NUMA) += node.o
diff --git a/drivers/base/dmapool.c b/drivers/base/dmapool.c
deleted file mode 100644
index b5034dc72a0..00000000000
--- a/drivers/base/dmapool.c
+++ /dev/null
@@ -1,481 +0,0 @@
-
-#include <linux/device.h>
-#include <linux/mm.h>
-#include <asm/io.h> /* Needed for i386 to build */
-#include <linux/dma-mapping.h>
-#include <linux/dmapool.h>
-#include <linux/slab.h>
-#include <linux/module.h>
-#include <linux/poison.h>
-#include <linux/sched.h>
-
-/*
- * Pool allocator ... wraps the dma_alloc_coherent page allocator, so
- * small blocks are easily used by drivers for bus mastering controllers.
- * This should probably be sharing the guts of the slab allocator.
- */
-
-struct dma_pool { /* the pool */
- struct list_head page_list;
- spinlock_t lock;
- size_t blocks_per_page;
- size_t size;
- struct device *dev;
- size_t allocation;
- char name [32];
- wait_queue_head_t waitq;
- struct list_head pools;
-};
-
-struct dma_page { /* cacheable header for 'allocation' bytes */
- struct list_head page_list;
- void *vaddr;
- dma_addr_t dma;
- unsigned in_use;
- unsigned long bitmap [0];
-};
-
-#define POOL_TIMEOUT_JIFFIES ((100 /* msec */ * HZ) / 1000)
-
-static DEFINE_MUTEX (pools_lock);
-
-static ssize_t
-show_pools (struct device *dev, struct device_attribute *attr, char *buf)
-{
- unsigned temp;
- unsigned size;
- char *next;
- struct dma_page *page;
- struct dma_pool *pool;
-
- next = buf;
- size = PAGE_SIZE;
-
- temp = scnprintf(next, size, "poolinfo - 0.1\n");
- size -= temp;
- next += temp;
-
- mutex_lock(&pools_lock);
- list_for_each_entry(pool, &dev->dma_pools, pools) {
- unsigned pages = 0;
- unsigned blocks = 0;
-
- list_for_each_entry(page, &pool->page_list, page_list) {
- pages++;
- blocks += page->in_use;
- }
-
- /* per-pool info, no real statistics yet */
- temp = scnprintf(next, size, "%-16s %4u %4Zu %4Zu %2u\n",
- pool->name,
- blocks, pages * pool->blocks_per_page,
- pool->size, pages);
- size -= temp;
- next += temp;
- }
- mutex_unlock(&pools_lock);
-
- return PAGE_SIZE - size;
-}
-static DEVICE_ATTR (pools, S_IRUGO, show_pools, NULL);
-
-/**
- * dma_pool_create - Creates a pool of consistent memory blocks, for dma.
- * @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)
- * Context: !in_interrupt()
- *
- * Returns a dma allocation pool with the requested characteristics, or
- * null if one can't be created. Given one of these pools, dma_pool_alloc()
- * may be used to allocate memory. Such memory will all have "consistent"
- * 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 allocation 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.
- */
-struct dma_pool *
-dma_pool_create (const char *name, struct device *dev,
- size_t size, size_t align, size_t allocation)
-{
- struct dma_pool *retval;
-
- if (align == 0)
- align = 1;
- if (size == 0)
- return NULL;
- else if (size < align)
- size = align;
- else if ((size % align) != 0) {
- size += align + 1;
- size &= ~(align - 1);
- }
-
- if (allocation == 0) {
- if (PAGE_SIZE < size)
- allocation = size;
- else
- allocation = PAGE_SIZE;
- // FIXME: round up for less fragmentation
- } else if (allocation < size)
- return NULL;
-
- if (!(retval = kmalloc_node (sizeof *retval, GFP_KERNEL, dev_to_node(dev))))
- return retval;
-
- strlcpy (retval->name, name, sizeof retval->name);
-
- retval->dev = dev;
-
- INIT_LIST_HEAD (&retval->page_list);
- spin_lock_init (&retval->lock);
- retval->size = size;
- retval->allocation = allocation;
- retval->blocks_per_page = allocation / size;
- init_waitqueue_head (&retval->waitq);
-
- if (dev) {
- int ret;
-
- mutex_lock(&pools_lock);
- if (list_empty (&dev->dma_pools))
- ret = device_create_file (dev, &dev_attr_pools);
- else
- ret = 0;
- /* note: not currently insisting "name" be unique */
- if (!ret)
- list_add (&retval->pools, &dev->dma_pools);
- else {
- kfree(retval);
- retval = NULL;
- }
- mutex_unlock(&pools_lock);
- } else
- INIT_LIST_HEAD (&retval->pools);
-
- return retval;
-}
-
-
-static struct dma_page *
-pool_alloc_page (struct dma_pool *pool, gfp_t mem_flags)
-{
- struct dma_page *page;
- int mapsize;
-
- mapsize = pool->blocks_per_page;
- mapsize = (mapsize + BITS_PER_LONG - 1) / BITS_PER_LONG;
- mapsize *= sizeof (long);
-
- page = kmalloc(mapsize + sizeof *page, mem_flags);
- if (!page)
- return NULL;
- page->vaddr = dma_alloc_coherent (pool->dev,
- pool->allocation,
- &page->dma,
- mem_flags);
- if (page->vaddr) {
- memset (page->bitmap, 0xff, mapsize); // bit set == free
-#ifdef CONFIG_DEBUG_SLAB
- memset (page->vaddr, POOL_POISON_FREED, pool->allocation);
-#endif
- list_add (&page->page_list, &pool->page_list);
- page->in_use = 0;
- } else {
- kfree (page);
- page = NULL;
- }
- return page;
-}
-
-
-static inline int
-is_page_busy (int blocks, unsigned long *bitmap)
-{
- while (blocks > 0) {
- if (*bitmap++ != ~0UL)
- return 1;
- blocks -= BITS_PER_LONG;
- }
- return 0;
-}
-
-static void
-pool_free_page (struct dma_pool *pool, struct dma_page *page)
-{
- dma_addr_t dma = page->dma;
-
-#ifdef CONFIG_DEBUG_SLAB
- memset (page->vaddr, POOL_POISON_FREED, pool->allocation);
-#endif
- dma_free_coherent (pool->dev, pool->allocation, page->vaddr, dma);
- list_del (&page->page_list);
- kfree (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)
-{
- mutex_lock(&pools_lock);
- list_del (&pool->pools);
- if (pool->dev && list_empty (&pool->dev->dma_pools))
- device_remove_file (pool->dev, &dev_attr_pools);
- mutex_unlock(&pools_lock);
-
- while (!list_empty (&pool->page_list)) {
- struct dma_page *page;
- page = list_entry (pool->page_list.next,
- struct dma_page, page_list);
- if (is_page_busy (pool->blocks_per_page, page->bitmap)) {
- if (pool->dev)
- dev_err(pool->dev, "dma_pool_destroy %s, %p busy\n",
- pool->name, page->vaddr);
- else
- printk (KERN_ERR "dma_pool_destroy %s, %p busy\n",
- pool->name, page->vaddr);
- /* leak the still-in-use consistent memory */
- list_del (&page->page_list);
- kfree (page);
- } else
- pool_free_page (pool, page);
- }
-
- kfree (pool);
-}
-
-
-/**
- * dma_pool_alloc - get a block of consistent memory
- * @pool: dma pool that will produce the block
- * @mem_flags: GFP_* bitmask
- * @handle: pointer to dma address of block
- *
- * This returns 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)
-{
- unsigned long flags;
- struct dma_page *page;
- int map, block;
- size_t offset;
- void *retval;
-
-restart:
- spin_lock_irqsave (&pool->lock, flags);
- list_for_each_entry(page, &pool->page_list, page_list) {
- int i;
- /* only cachable accesses here ... */
- for (map = 0, i = 0;
- i < pool->blocks_per_page;
- i += BITS_PER_LONG, map++) {
- if (page->bitmap [map] == 0)
- continue;
- block = ffz (~ page->bitmap [map]);
- if ((i + block) < pool->blocks_per_page) {
- clear_bit (block, &page->bitmap [map]);
- offset = (BITS_PER_LONG * map) + block;
- offset *= pool->size;
- goto ready;
- }
- }
- }
- if (!(page = pool_alloc_page (pool, GFP_ATOMIC))) {
- if (mem_flags & __GFP_WAIT) {
- DECLARE_WAITQUEUE (wait, current);
-
- __set_current_state(TASK_INTERRUPTIBLE);
- add_wait_queue (&pool->waitq, &wait);
- spin_unlock_irqrestore (&pool->lock, flags);
-
- schedule_timeout (POOL_TIMEOUT_JIFFIES);
-
- remove_wait_queue (&pool->waitq, &wait);
- goto restart;
- }
- retval = NULL;
- goto done;
- }
-
- clear_bit (0, &page->bitmap [0]);
- offset = 0;
-ready:
- page->in_use++;
- retval = offset + page->vaddr;
- *handle = offset + page->dma;
-#ifdef CONFIG_DEBUG_SLAB
- memset (retval, POOL_POISON_ALLOCATED, pool->size);
-#endif
-done:
- spin_unlock_irqrestore (&pool->lock, flags);
- return retval;
-}
-
-
-static struct dma_page *
-pool_find_page (struct dma_pool *pool, dma_addr_t dma)
-{
- unsigned long flags;
- struct dma_page *page;
-
- spin_lock_irqsave (&pool->lock, flags);
- list_for_each_entry(page, &pool->page_list, page_list) {
- if (dma < page->dma)
- continue;
- if (dma < (page->dma + pool->allocation))
- goto done;
- }
- page = NULL;
-done:
- spin_unlock_irqrestore (&pool->lock, flags);
- return page;
-}
-
-
-/**
- * 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_page *page;
- unsigned long flags;
- int map, block;
-
- if ((page = pool_find_page(pool, dma)) == NULL) {
- if (pool->dev)
- dev_err(pool->dev, "dma_pool_free %s, %p/%lx (bad dma)\n",
- pool->name, vaddr, (unsigned long) dma);
- else
- printk (KERN_ERR "dma_pool_free %s, %p/%lx (bad dma)\n",
- pool->name, vaddr, (unsigned long) dma);
- return;
- }
-
- block = dma - page->dma;
- block /= pool->size;
- map = block / BITS_PER_LONG;
- block %= BITS_PER_LONG;
-
-#ifdef CONFIG_DEBUG_SLAB
- if (((dma - page->dma) + (void *)page->vaddr) != vaddr) {
- if (pool->dev)
- dev_err(pool->dev, "dma_pool_free %s, %p (bad vaddr)/%Lx\n",
- pool->name, vaddr, (unsigned long long) dma);
- else
- printk (KERN_ERR "dma_pool_free %s, %p (bad vaddr)/%Lx\n",
- pool->name, vaddr, (unsigned long long) dma);
- return;
- }
- if (page->bitmap [map] & (1UL << block)) {
- if (pool->dev)
- dev_err(pool->dev, "dma_pool_free %s, dma %Lx already free\n",
- pool->name, (unsigned long long)dma);
- else
- printk (KERN_ERR "dma_pool_free %s, dma %Lx already free\n",
- pool->name, (unsigned long long)dma);
- return;
- }
- memset (vaddr, POOL_POISON_FREED, pool->size);
-#endif
-
- spin_lock_irqsave (&pool->lock, flags);
- page->in_use--;
- set_bit (block, &page->bitmap [map]);
- if (waitqueue_active (&pool->waitq))
- wake_up (&pool->waitq);
- /*
- * Resist a temptation to do
- * if (!is_page_busy(bpp, page->bitmap)) pool_free_page(pool, page);
- * Better have a few empty pages hang around.
- */
- spin_unlock_irqrestore (&pool->lock, flags);
-}
-
-/*
- * 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.
- */
-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;
-
- ptr = devres_alloc(dmam_pool_release, sizeof(*ptr), GFP_KERNEL);
- if (!ptr)
- return NULL;
-
- pool = *ptr = dma_pool_create(name, dev, size, align, allocation);
- if (pool)
- devres_add(dev, ptr);
- else
- devres_free(ptr);
-
- return pool;
-}
-
-/**
- * dmam_pool_destroy - Managed dma_pool_destroy()
- * @pool: dma pool that will be destroyed
- *
- * Managed dma_pool_destroy().
- */
-void dmam_pool_destroy(struct dma_pool *pool)
-{
- struct device *dev = pool->dev;
-
- dma_pool_destroy(pool);
- WARN_ON(devres_destroy(dev, dmam_pool_release, dmam_pool_match, pool));
-}
-
-EXPORT_SYMBOL (dma_pool_create);
-EXPORT_SYMBOL (dma_pool_destroy);
-EXPORT_SYMBOL (dma_pool_alloc);
-EXPORT_SYMBOL (dma_pool_free);
-EXPORT_SYMBOL (dmam_pool_create);
-EXPORT_SYMBOL (dmam_pool_destroy);
diff --git a/mm/Makefile b/mm/Makefile
index 44e2528af70..4af5dff3727 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -16,6 +16,7 @@ obj-y := bootmem.o filemap.o mempool.o oom_kill.o fadvise.o \
obj-$(CONFIG_PROC_PAGE_MONITOR) += pagewalk.o
obj-$(CONFIG_BOUNCE) += bounce.o
obj-$(CONFIG_SWAP) += page_io.o swap_state.o swapfile.o thrash.o
+obj-$(CONFIG_HAS_DMA) += dmapool.o
obj-$(CONFIG_HUGETLBFS) += hugetlb.o
obj-$(CONFIG_NUMA) += mempolicy.o
obj-$(CONFIG_SPARSEMEM) += sparse.o
diff --git a/mm/dmapool.c b/mm/dmapool.c
new file mode 100644
index 00000000000..34aaac451a9
--- /dev/null
+++ b/mm/dmapool.c
@@ -0,0 +1,500 @@
+/*
+ * DMA Pool allocator
+ *
+ * Copyright 2001 David Brownell
+ * Copyright 2007 Intel Corporation
+ * Author: Matthew Wilcox <willy@linux.intel.com>
+ *
+ * This software may be redistributed and/or modified under the terms of
+ * the GNU General Public License ("GPL") version 2 as published by the
+ * Free Software Foundation.
+ *
+ * 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 within the page. 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/module.h>
+#include <linux/mutex.h>
+#include <linux/poison.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+
+struct dma_pool { /* the pool */
+ struct list_head page_list;
+ spinlock_t lock;
+ size_t size;
+ struct device *dev;
+ size_t allocation;
+ size_t boundary;
+ char name[32];
+ wait_queue_head_t waitq;
+ struct list_head pools;
+};
+
+struct dma_page { /* cacheable header for 'allocation' bytes */
+ struct list_head page_list;
+ void *vaddr;
+ dma_addr_t dma;
+ unsigned int in_use;
+ unsigned int offset;
+};
+
+#define POOL_TIMEOUT_JIFFIES ((100 /* msec */ * HZ) / 1000)
+
+static DEFINE_MUTEX(pools_lock);
+
+static ssize_t
+show_pools(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ unsigned temp;
+ unsigned size;
+ char *next;
+ struct dma_page *page;
+ struct dma_pool *pool;
+
+ next = buf;
+ size = PAGE_SIZE;
+
+ temp = scnprintf(next, size, "poolinfo - 0.1\n");
+ size -= temp;
+ next += temp;
+
+ mutex_lock(&pools_lock);
+ list_for_each_entry(pool, &dev->dma_pools, pools) {
+ unsigned pages = 0;
+ unsigned blocks = 0;
+
+ list_for_each_entry(page, &pool->page_list, page_list) {
+ pages++;
+ blocks += page->in_use;
+ }
+
+ /* per-pool info, no real statistics yet */
+ temp = scnprintf(next, size, "%-16s %4u %4Zu %4Zu %2u\n",
+ pool->name, blocks,
+ pages * (pool->allocation / pool->size),
+ pool->size, pages);
+ size -= temp;
+ next += temp;
+ }
+ mutex_unlock(&pools_lock);
+
+ return PAGE_SIZE - size;
+}
+
+static DEVICE_ATTR(pools, S_IRUGO, show_pools, NULL);
+
+/**
+ * dma_pool_create - Creates a pool of consistent memory blocks, for dma.
+ * @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
+ * Context: !in_interrupt()
+ *
+ * Returns a dma allocation pool with the requested characteristics, or
+ * null if one can't be created. Given one of these pools, dma_pool_alloc()
+ * may be used to allocate memory. Such memory will all have "consistent"
+ * 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.
+ */
+struct dma_pool *dma_pool_create(const char *name, struct device *dev,
+ size_t size, size_t align, size_t boundary)
+{
+ struct dma_pool *retval;
+ size_t allocation;
+
+ if (align == 0) {
+ align = 1;
+ } else if (align & (align - 1)) {
+ return NULL;
+ }
+
+ if (size == 0) {
+ return NULL;
+ } else if (size < 4) {
+ size = 4;
+ }
+
+ if ((size % align) != 0)
+ 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;
+ }
+
+ retval = kmalloc_node(sizeof(*retval), GFP_KERNEL, dev_to_node(dev));
+ if (!retval)
+ return retval;
+
+ strlcpy(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;
+ init_waitqueue_head(&retval->waitq);
+
+ if (dev) {
+ int ret;
+
+ mutex_lock(&pools_lock);
+ if (list_empty(&dev->dma_pools))
+ ret = device_create_file(dev, &dev_attr_pools);
+ else
+ ret = 0;
+ /* note: not currently insisting "name" be unique */
+ if (!ret)
+ list_add(&retval->pools, &dev->dma_pools);
+ else {
+ kfree(retval);
+ retval = NULL;
+ }
+ mutex_unlock(&pools_lock);
+ } else
+ INIT_LIST_HEAD(&retval->pools);
+
+ return retval;
+}
+EXPORT_SYMBOL(dma_pool_create);
+
+static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page)
+{
+ unsigned int offset = 0;
+ unsigned int next_boundary = pool->boundary;
+
+ do {
+ unsigned int next = offset + pool->size;
+ if (unlikely((next + pool->size) >= next_boundary)) {
+ next = next_boundary;
+ next_boundary += pool->boundary;
+ }
+ *(int *)(page->vaddr + offset) = next;
+ offset = next;
+ } while (offset < pool->allocation);
+}
+
+static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags)
+{
+ struct dma_page *page;
+
+ page = kmalloc(sizeof(*page), mem_flags);
+ if (!page)
+ return NULL;
+ page->vaddr = dma_alloc_coherent(pool->dev, pool->allocation,
+ &page->dma, mem_flags);
+ if (page->vaddr) {
+#ifdef CONFIG_DEBUG_SLAB
+ memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
+#endif
+ pool_initialise_page(pool, page);
+ list_add(&page->page_list, &pool->page_list);
+ page->in_use = 0;
+ page->offset = 0;
+ } else {
+ kfree(page);
+ page = NULL;
+ }
+ return page;
+}
+
+static inline int is_page_busy(struct dma_page *page)
+{
+ return page->in_use != 0;
+}
+
+static void pool_free_page(struct dma_pool *pool, struct dma_page *page)
+{
+ dma_addr_t dma = page->dma;
+
+#ifdef CONFIG_DEBUG_SLAB
+ memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
+#endif
+ dma_free_coherent(pool->dev, pool->allocation, page->vaddr, dma);
+ list_del(&page->page_list);
+ kfree(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)
+{
+ mutex_lock(&pools_lock);
+ list_del(&pool->pools);
+ if (pool->dev && list_empty(&pool->dev->dma_pools))
+ device_remove_file(pool->dev, &dev_attr_pools);
+ mutex_unlock(&pools_lock);
+
+ while (!list_empty(&pool->page_list)) {
+ struct dma_page *page;
+ page = list_entry(pool->page_list.next,
+ struct dma_page, page_list);
+ if (is_page_busy(page)) {
+ if (pool->dev)
+ dev_err(pool->dev,
+ "dma_pool_destroy %s, %p busy\n",
+ pool->name, page->vaddr);
+ else
+ printk(KERN_ERR
+ "dma_pool_destroy %s, %p busy\n",
+ pool->name, page->vaddr);
+ /* leak the still-in-use consistent memory */
+ list_del(&page->page_list);
+ kfree(page);
+ } else
+ pool_free_page(pool, page);
+ }
+
+ kfree(pool);
+}
+EXPORT_SYMBOL(dma_pool_destroy);
+
+/**
+ * dma_pool_alloc - get a block of consistent memory
+ * @pool: dma pool that will produce the block
+ * @mem_flags: GFP_* bitmask
+ * @handle: pointer to dma address of block
+ *
+ * This returns 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)
+{
+ unsigned long flags;
+ struct dma_page *page;
+ size_t offset;
+ void *retval;
+
+ spin_lock_irqsave(&pool->lock, flags);
+ restart:
+ list_for_each_entry(page, &pool->page_list, page_list) {
+ if (page->offset < pool->allocation)
+ goto ready;
+ }
+ page = pool_alloc_page(pool, GFP_ATOMIC);
+ if (!page) {
+ if (mem_flags & __GFP_WAIT) {
+ DECLARE_WAITQUEUE(wait, current);
+
+ __set_current_state(TASK_INTERRUPTIBLE);
+ __add_wait_queue(&pool->waitq, &wait);
+ spin_unlock_irqrestore(&pool->lock, flags);
+
+ schedule_timeout(POOL_TIMEOUT_JIFFIES);
+
+ spin_lock_irqsave(&pool->lock, flags);
+ __remove_wait_queue(&pool->waitq, &wait);
+ goto restart;
+ }
+ retval = NULL;
+ goto done;
+ }
+
+ ready:
+ page->in_use++;
+ offset = page->offset;
+ page->offset = *(int *)(page->vaddr + offset);
+ retval = offset + page->vaddr;
+ *handle = offset + page->dma;
+#ifdef CONFIG_DEBUG_SLAB
+ memset(retval, POOL_POISON_ALLOCATED, pool->size);
+#endif
+ done:
+ spin_unlock_irqrestore(&pool->lock, flags);
+ return retval;
+}
+EXPORT_SYMBOL(dma_pool_alloc);
+
+static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma)
+{
+ unsigned long flags;
+ struct dma_page *page;
+
+ spin_lock_irqsave(&pool->lock, flags);
+ list_for_each_entry(page, &pool->page_list, page_list) {
+ if (dma < page->dma)
+ continue;
+ if (dma < (page->dma + pool->allocation))
+ goto done;
+ }
+ page = NULL;
+ done:
+ spin_unlock_irqrestore(&pool->lock, flags);
+ return page;
+}
+
+/**
+ * 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_page *page;
+ unsigned long flags;
+ unsigned int offset;
+
+ page = pool_find_page(pool, dma);
+ if (!page) {
+ if (pool->dev)
+ dev_err(pool->dev,
+ "dma_pool_free %s, %p/%lx (bad dma)\n",
+ pool->name, vaddr, (unsigned long)dma);
+ else
+ printk(KERN_ERR "dma_pool_free %s, %p/%lx (bad dma)\n",
+ pool->name, vaddr, (unsigned long)dma);
+ return;
+ }
+
+ offset = vaddr - page->vaddr;
+#ifdef CONFIG_DEBUG_SLAB
+ if ((dma - page->dma) != offset) {
+ if (pool->dev)
+ dev_err(pool->dev,
+ "dma_pool_free %s, %p (bad vaddr)/%Lx\n",
+ pool->name, vaddr, (unsigned long long)dma);
+ else
+ printk(KERN_ERR
+ "dma_pool_free %s, %p (bad vaddr)/%Lx\n",
+ pool->name, vaddr, (unsigned long long)dma);
+ return;
+ }
+ {
+ unsigned int chain = page->offset;
+ while (chain < pool->allocation) {
+ if (chain != offset) {
+ chain = *(int *)(page->vaddr + chain);
+ continue;
+ }
+ if (pool->dev)
+ dev_err(pool->dev, "dma_pool_free %s, dma %Lx "
+ "already free\n", pool->name,
+ (unsigned long long)dma);
+ else
+ printk(KERN_ERR "dma_pool_free %s, dma %Lx "
+ "already free\n", pool->name,
+ (unsigned long long)dma);
+ return;
+ }
+ }
+ memset(vaddr, POOL_POISON_FREED, pool->size);
+#endif
+
+ spin_lock_irqsave(&pool->lock, flags);
+ page->in_use--;
+ *(int *)vaddr = page->offset;
+ page->offset = offset;
+ if (waitqueue_active(&pool->waitq))
+ wake_up_locked(&pool->waitq);
+ /*
+ * Resist a temptation to do
+ * if (!is_page_busy(page)) pool_free_page(pool, page);
+ * Better have a few empty pages hang around.
+ */
+ 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.
+ */
+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;
+
+ ptr = devres_alloc(dmam_pool_release, sizeof(*ptr), GFP_KERNEL);
+ if (!ptr)
+ return NULL;
+
+ pool = *ptr = dma_pool_create(name, dev, size, align, allocation);
+ if (pool)
+ devres_add(dev, ptr);
+ else
+ devres_free(ptr);
+
+ return pool;
+}
+EXPORT_SYMBOL(dmam_pool_create);
+
+/**
+ * dmam_pool_destroy - Managed dma_pool_destroy()
+ * @pool: dma pool that will be destroyed
+ *
+ * Managed dma_pool_destroy().
+ */
+void dmam_pool_destroy(struct dma_pool *pool)
+{
+ struct device *dev = pool->dev;
+
+ dma_pool_destroy(pool);
+ WARN_ON(devres_destroy(dev, dmam_pool_release, dmam_pool_match, pool));
+}
+EXPORT_SYMBOL(dmam_pool_destroy);