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authorLudovic Desroches <ludovic.desroches@atmel.com>2013-04-18 09:52:59 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2013-04-18 08:54:22 -0700
commitd202f05158442396033f416df376f8ece1f563df (patch)
tree1c08c8128ac638606af144eec1338c864310a3d4 /drivers
parentebe80544338a393e94b65995120c3028c80abc62 (diff)
downloadvexpress-lsk-d202f05158442396033f416df376f8ece1f563df.tar.gz
dmaengine: at_hdmac: fix race condition in atc_advance_work()
The BUG_ON() directive is triggered probably due to a latency modification following inclusion of commit c10d73671ad3 ("softirq: reduce latencies"). This condition has not been met before 3.9-rc1 and doesn't trigger without this patch. We now make sure that DMA channel is idle before calling atc_complete_all() which makes the BUG_ON() "protection" useless. Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com> Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com> Acked-by: Vinod Koul <vinod.koul@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/dma/at_hdmac.c9
1 files changed, 4 insertions, 5 deletions
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index 6e13f262139..88cfc61329d 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -310,8 +310,6 @@ static void atc_complete_all(struct at_dma_chan *atchan)
dev_vdbg(chan2dev(&atchan->chan_common), "complete all\n");
- BUG_ON(atc_chan_is_enabled(atchan));
-
/*
* Submit queued descriptors ASAP, i.e. before we go through
* the completed ones.
@@ -368,6 +366,9 @@ static void atc_advance_work(struct at_dma_chan *atchan)
{
dev_vdbg(chan2dev(&atchan->chan_common), "advance_work\n");
+ if (atc_chan_is_enabled(atchan))
+ return;
+
if (list_empty(&atchan->active_list) ||
list_is_singular(&atchan->active_list)) {
atc_complete_all(atchan);
@@ -1078,9 +1079,7 @@ static void atc_issue_pending(struct dma_chan *chan)
return;
spin_lock_irqsave(&atchan->lock, flags);
- if (!atc_chan_is_enabled(atchan)) {
- atc_advance_work(atchan);
- }
+ atc_advance_work(atchan);
spin_unlock_irqrestore(&atchan->lock, flags);
}