dmaengine: at_hdmac: fix race while monitoring channel status
Nicolas Ferre [Wed, 12 Jan 2011 14:39:10 +0000 (15:39 +0100)]
We were reading channel status then taking a lock. This lead to a race because
this lock may delay us and then make this channel not idle anymore.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/dma/at_hdmac.c

index 3938db2..40f2bf4 100644 (file)
@@ -853,11 +853,11 @@ static void atc_issue_pending(struct dma_chan *chan)
 
        dev_vdbg(chan2dev(chan), "issue_pending\n");
 
+       spin_lock_bh(&atchan->lock);
        if (!atc_chan_is_enabled(atchan)) {
-               spin_lock_bh(&atchan->lock);
                atc_advance_work(atchan);
-               spin_unlock_bh(&atchan->lock);
        }
+       spin_unlock_bh(&atchan->lock);
 }
 
 /**