dma_pool_free() scans for the page to free in the pool list holding the
pool lock. Then it releases the lock basically to acquire it immediately
again. Modify the code to only take the lock once.
This will do some additional loops and computations with the lock held in
if memory debugging is activated. If it is not activated the only new
operations with this lock is one if and one substraction.
Signed-off-by: Rolf Eike Beer <eike-kernel@sf-tec.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma)
{
static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma)
{
- 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))
list_for_each_entry(page, &pool->page_list, page_list) {
if (dma < page->dma)
continue;
if (dma < (page->dma + pool->allocation))
- page = NULL;
- done:
- spin_unlock_irqrestore(&pool->lock, flags);
- return page;
unsigned long flags;
unsigned int offset;
unsigned long flags;
unsigned int offset;
+ spin_lock_irqsave(&pool->lock, flags);
page = pool_find_page(pool, dma);
if (!page) {
page = pool_find_page(pool, dma);
if (!page) {
+ spin_unlock_irqrestore(&pool->lock, flags);
if (pool->dev)
dev_err(pool->dev,
"dma_pool_free %s, %p/%lx (bad dma)\n",
if (pool->dev)
dev_err(pool->dev,
"dma_pool_free %s, %p/%lx (bad dma)\n",
offset = vaddr - page->vaddr;
#ifdef DMAPOOL_DEBUG
if ((dma - page->dma) != offset) {
offset = vaddr - page->vaddr;
#ifdef DMAPOOL_DEBUG
if ((dma - page->dma) != offset) {
+ spin_unlock_irqrestore(&pool->lock, flags);
if (pool->dev)
dev_err(pool->dev,
"dma_pool_free %s, %p (bad vaddr)/%Lx\n",
if (pool->dev)
dev_err(pool->dev,
"dma_pool_free %s, %p (bad vaddr)/%Lx\n",
chain = *(int *)(page->vaddr + chain);
continue;
}
chain = *(int *)(page->vaddr + chain);
continue;
}
+ spin_unlock_irqrestore(&pool->lock, flags);
if (pool->dev)
dev_err(pool->dev, "dma_pool_free %s, dma %Lx "
"already free\n", pool->name,
if (pool->dev)
dev_err(pool->dev, "dma_pool_free %s, dma %Lx "
"already free\n", pool->name,
memset(vaddr, POOL_POISON_FREED, pool->size);
#endif
memset(vaddr, POOL_POISON_FREED, pool->size);
#endif
- spin_lock_irqsave(&pool->lock, flags);
page->in_use--;
*(int *)vaddr = page->offset;
page->offset = offset;
page->in_use--;
*(int *)vaddr = page->offset;
page->offset = offset;