This is a note to let you know that I've just added the patch titled
mm: dmapool: use provided gfp flags for all dma_alloc_coherent() calls
to the 3.7-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-dmapool-use-provided-gfp-flags-for-all-dma_alloc_coherent-calls.patch
and it can be found in the queue-3.7 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 387870f2d6d679746020fa8e25ef786ff338dc98 Mon Sep 17 00:00:00 2001
From: Marek Szyprowski <[email protected]>
Date: Wed, 7 Nov 2012 15:37:07 +0100
Subject: mm: dmapool: use provided gfp flags for all dma_alloc_coherent() calls
From: Marek Szyprowski <[email protected]>
commit 387870f2d6d679746020fa8e25ef786ff338dc98 upstream.
dmapool always calls dma_alloc_coherent() with GFP_ATOMIC flag,
regardless the flags provided by the caller. This causes excessive
pruning of emergency memory pools without any good reason. Additionaly,
on ARM architecture any driver which is using dmapools will sooner or
later trigger the following error:
"ERROR: 256 KiB atomic DMA coherent pool is too small!
Please increase it with coherent_pool= kernel parameter!".
Increasing the coherent pool size usually doesn't help much and only
delays such error, because all GFP_ATOMIC DMA allocations are always
served from the special, very limited memory pool.
This patch changes the dmapool code to correctly use gfp flags provided
by the dmapool caller.
Reported-by: Soeren Moch <[email protected]>
Reported-by: Thomas Petazzoni <[email protected]>
Signed-off-by: Marek Szyprowski <[email protected]>
Tested-by: Andrew Lunn <[email protected]>
Tested-by: Soeren Moch <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
mm/dmapool.c | 31 +++++++------------------------
1 file changed, 7 insertions(+), 24 deletions(-)
--- a/mm/dmapool.c
+++ b/mm/dmapool.c
@@ -50,7 +50,6 @@ struct dma_pool { /* the pool */
size_t allocation;
size_t boundary;
char name[32];
- wait_queue_head_t waitq;
struct list_head pools;
};
@@ -62,8 +61,6 @@ struct dma_page { /* cacheable header f
unsigned int offset;
};
-#define POOL_TIMEOUT_JIFFIES ((100 /* msec */ * HZ) / 1000)
-
static DEFINE_MUTEX(pools_lock);
static ssize_t
@@ -172,7 +169,6 @@ struct dma_pool *dma_pool_create(const c
retval->size = size;
retval->boundary = boundary;
retval->allocation = allocation;
- init_waitqueue_head(&retval->waitq);
if (dev) {
int ret;
@@ -227,7 +223,6 @@ static struct dma_page *pool_alloc_page(
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 {
@@ -315,30 +310,21 @@ void *dma_pool_alloc(struct dma_pool *po
might_sleep_if(mem_flags & __GFP_WAIT);
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_UNINTERRUPTIBLE);
- __add_wait_queue(&pool->waitq, &wait);
- spin_unlock_irqrestore(&pool->lock, flags);
+ /* pool_alloc_page() might sleep, so temporarily drop &pool->lock */
+ spin_unlock_irqrestore(&pool->lock, flags);
- schedule_timeout(POOL_TIMEOUT_JIFFIES);
+ page = pool_alloc_page(pool, mem_flags);
+ if (!page)
+ return NULL;
- spin_lock_irqsave(&pool->lock, flags);
- __remove_wait_queue(&pool->waitq, &wait);
- goto restart;
- }
- retval = NULL;
- goto done;
- }
+ spin_lock_irqsave(&pool->lock, flags);
+ list_add(&page->page_list, &pool->page_list);
ready:
page->in_use++;
offset = page->offset;
@@ -348,7 +334,6 @@ void *dma_pool_alloc(struct dma_pool *po
#ifdef DMAPOOL_DEBUG
memset(retval, POOL_POISON_ALLOCATED, pool->size);
#endif
- done:
spin_unlock_irqrestore(&pool->lock, flags);
return retval;
}
@@ -435,8 +420,6 @@ void dma_pool_free(struct dma_pool *pool
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);
Patches currently in stable-queue which might be from [email protected]
are
queue-3.7/mm-dmapool-use-provided-gfp-flags-for-all-dma_alloc_coherent-calls.patch
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