diff options
| author | Ludovic Desroches <ludovic.desroches@atmel.com> | 2013-04-18 11:52:59 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-04-18 19:54:22 +0400 |
| commit | d202f05158442396033f416df376f8ece1f563df (patch) | |
| tree | 1c08c8128ac638606af144eec1338c864310a3d4 | |
| parent | ebe80544338a393e94b65995120c3028c80abc62 (diff) | |
| download | linux-d202f05158442396033f416df376f8ece1f563df.tar.xz | |
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>
| -rw-r--r-- | drivers/dma/at_hdmac.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c index 6e13f262139a..88cfc61329d2 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); } |