1 files changed, 130 insertions, 127 deletions

diff --git a/mm/dmapool.c b/mm/dmapool.c
index 21e6d362c726..d2b0f8fc9649 100644
--- a/mm/dmapool.c
+++ b/mm/dmapool.c
@@ -15,7 +15,7 @@
  * 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
+ * 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.
  */
 
@@ -40,9 +40,18 @@
 #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;
@@ -55,8 +64,6 @@ 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;
 };
 
 static DEFINE_MUTEX(pools_lock);
@@ -64,30 +71,18 @@ static DEFINE_MUTEX(pools_reg_lock);
 
 static ssize_t pools_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	int size;
-	struct dma_page *page;
 	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) {
-		unsigned pages = 0;
-		size_t blocks = 0;
-
-		spin_lock_irq(&pool->lock);
-		list_for_each_entry(page, &pool->page_list, page_list) {
-			pages++;
-			blocks += page->in_use;
-		}
-		spin_unlock_irq(&pool->lock);
-
 		/* per-pool info, no real statistics yet */
-		size += sysfs_emit_at(buf, size, "%-16s %4zu %4zu %4u %2u\n",
-				      pool->name, blocks,
-				      (size_t) pages *
-				      (pool->allocation / pool->size),
-				      pool->size, pages);
+		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);
 
@@ -97,17 +92,17 @@ static ssize_t pools_show(struct device *dev, struct device_attribute *attr, cha
 static DEVICE_ATTR_RO(pools);
 
 #ifdef DMAPOOL_DEBUG
-static void pool_check_block(struct dma_pool *pool, void *retval,
-			     unsigned int offset, gfp_t mem_flags)
+static void pool_check_block(struct dma_pool *pool, struct dma_block *block,
+			     gfp_t mem_flags)
 {
+	u8 *data = (void *)block;
 	int i;
-	u8 *data = retval;
-	/* page->offset is stored in first 4 bytes */
-	for (i = sizeof(offset); i < pool->size; 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, retval);
+		dev_err(pool->dev, "%s %s, %p (corrupted)\n", __func__,
+			pool->name, block);
 
 		/*
 		 * Dump the first 4 bytes even if they are not
@@ -117,31 +112,46 @@ static void pool_check_block(struct dma_pool *pool, void *retval,
 				data, pool->size, 1);
 		break;
 	}
+
 	if (!want_init_on_alloc(mem_flags))
-		memset(retval, POOL_POISON_ALLOCATED, pool->size);
+		memset(block, POOL_POISON_ALLOCATED, pool->size);
 }
 
-static bool pool_page_err(struct dma_pool *pool, struct dma_page *page,
-			  void *vaddr, dma_addr_t dma)
+static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma)
 {
-	unsigned int offset = vaddr - page->vaddr;
-	unsigned int chain = page->offset;
+	struct dma_page *page;
 
-	if ((dma - page->dma) != offset) {
-		dev_err(pool->dev, "%s %s, %p (bad vaddr)/%pad\n",
+	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 (chain < pool->allocation) {
-		if (chain != offset) {
-			chain = *(int *)(page->vaddr + chain);
+	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;
 }
@@ -151,14 +161,12 @@ 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, void *retval,
-			     unsigned int offset, gfp_t mem_flags)
-
+static void pool_check_block(struct dma_pool *pool, struct dma_block *block,
+			     gfp_t mem_flags)
 {
 }
 
-static bool pool_page_err(struct dma_pool *pool, struct dma_page *page,
-			  void *vaddr, dma_addr_t dma)
+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);
@@ -170,6 +178,26 @@ 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 - Creates a pool of consistent memory blocks, for dma.
  * @name: name of pool, for diagnostics
@@ -210,8 +238,8 @@ struct dma_pool *dma_pool_create(const char *name, struct device *dev,
 
 	if (size == 0 || size > INT_MAX)
 		return NULL;
-	else if (size < 4)
-		size = 4;
+	if (size < sizeof(struct dma_block))
+		size = sizeof(struct dma_block);
 
 	size = ALIGN(size, align);
 	allocation = max_t(size_t, size, PAGE_SIZE);
@@ -223,7 +251,7 @@ struct dma_pool *dma_pool_create(const char *name, struct device *dev,
 
 	boundary = min(boundary, allocation);
 
-	retval = kmalloc(sizeof(*retval), GFP_KERNEL);
+	retval = kzalloc(sizeof(*retval), GFP_KERNEL);
 	if (!retval)
 		return retval;
 
@@ -236,7 +264,6 @@ struct dma_pool *dma_pool_create(const char *name, struct device *dev,
 	retval->size = size;
 	retval->boundary = boundary;
 	retval->allocation = allocation;
-
 	INIT_LIST_HEAD(&retval->pools);
 
 	/*
@@ -273,21 +300,36 @@ 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;
+	unsigned int next_boundary = pool->boundary, offset = 0;
+	struct dma_block *block, *first = NULL, *last = NULL;
 
 	pool_init_page(pool, page);
-	page->in_use = 0;
-	page->offset = 0;
-	do {
-		unsigned int next = offset + pool->size;
-		if (unlikely((next + pool->size) >= next_boundary)) {
-			next = next_boundary;
+	while (offset + pool->size <= pool->allocation) {
+		if (offset + pool->size > next_boundary) {
+			offset = next_boundary;
 			next_boundary += pool->boundary;
+			continue;
 		}
-		*(int *)(page->vaddr + offset) = next;
-		offset = next;
-	} while (offset < pool->allocation);
+
+		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)
@@ -305,15 +347,9 @@ static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags)
 		return NULL;
 	}
 
-	pool_initialise_page(pool, page);
 	return page;
 }
 
-static inline bool is_page_busy(struct dma_page *page)
-{
-	return page->in_use != 0;
-}
-
 /**
  * dma_pool_destroy - destroys a pool of dma memory blocks.
  * @pool: dma pool that will be destroyed
@@ -325,7 +361,7 @@ static inline bool is_page_busy(struct dma_page *page)
 void dma_pool_destroy(struct dma_pool *pool)
 {
 	struct dma_page *page, *tmp;
-	bool empty = false;
+	bool empty = false, busy = false;
 
 	if (unlikely(!pool))
 		return;
@@ -340,13 +376,15 @@ void dma_pool_destroy(struct dma_pool *pool)
 		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 (!is_page_busy(page))
+		if (!busy)
 			dma_free_coherent(pool->dev, pool->allocation,
 					  page->vaddr, page->dma);
-		else
-			dev_err(pool->dev, "%s %s, %p busy\n", __func__,
-				pool->name, page->vaddr);
 		list_del(&page->page_list);
 		kfree(page);
 	}
@@ -368,58 +406,40 @@ EXPORT_SYMBOL(dma_pool_destroy);
 void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags,
 		     dma_addr_t *handle)
 {
-	unsigned long flags;
+	struct dma_block *block;
 	struct dma_page *page;
-	unsigned int offset;
-	void *retval;
+	unsigned long flags;
 
 	might_alloc(mem_flags);
 
 	spin_lock_irqsave(&pool->lock, flags);
-	list_for_each_entry(page, &pool->page_list, page_list) {
-		if (page->offset < pool->allocation)
-			goto ready;
-	}
-
-	/* 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;
+	block = pool_block_pop(pool);
+	if (!block) {
+		/*
+		 * pool_alloc_page() might sleep, so temporarily drop
+		 * &pool->lock
+		 */
+		spin_unlock_irqrestore(&pool->lock, flags);
 
-	spin_lock_irqsave(&pool->lock, flags);
+		page = pool_alloc_page(pool, mem_flags & (~__GFP_ZERO));
+		if (!page)
+			return NULL;
 
-	list_add(&page->page_list, &pool->page_list);
- ready:
-	page->in_use++;
-	offset = page->offset;
-	page->offset = *(int *)(page->vaddr + offset);
-	retval = offset + page->vaddr;
-	*handle = offset + page->dma;
-	pool_check_block(pool, retval, offset, mem_flags);
+		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(retval, 0, pool->size);
+		memset(block, 0, pool->size);
 
-	return retval;
+	return block;
 }
 EXPORT_SYMBOL(dma_pool_alloc);
 
-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;
-}
-
 /**
  * dma_pool_free - put block back into dma pool
  * @pool: the dma pool holding the block
@@ -431,31 +451,14 @@ static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma)
  */
 void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma)
 {
-	struct dma_page *page;
+	struct dma_block *block = vaddr;
 	unsigned long flags;
 
 	spin_lock_irqsave(&pool->lock, flags);
-	page = pool_find_page(pool, dma);
-	if (!page) {
-		spin_unlock_irqrestore(&pool->lock, flags);
-		dev_err(pool->dev, "%s %s, %p/%pad (bad dma)\n",
-			__func__, pool->name, vaddr, &dma);
-		return;
-	}
-
-	if (pool_page_err(pool, page, vaddr, dma)) {
-		spin_unlock_irqrestore(&pool->lock, flags);
-		return;
+	if (!pool_block_err(pool, vaddr, dma)) {
+		pool_block_push(pool, block, dma);
+		pool->nr_active--;
 	}
-
-	page->in_use--;
-	*(int *)vaddr = page->offset;
-	page->offset = vaddr - page->vaddr;
-	/*
-	 * 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);