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authorJavi Merino <javi.merino@arm.com>2011-10-18 11:50:07 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2011-10-22 22:11:23 +0100
commitee3f615819404a9438b2dd01b7a39f276d2737f2 (patch)
tree8b725dfe99118faef327d163cf02a5fff28d8bf4 /arch/arm/common
parentb55fa18817743c3c4aef14f0c6fc0e21d7bc1e62 (diff)
ARM: 7136/1: pl330: Fix a race condition
If two requests have been submitted and one of them is running, if you call pl330_chan_ctrl(ch_id, PL330_OP_START), there's a window of time between the spin_lock_irqsave() and the _state() check in which the running transaction may finish. In that case, we don't receive the interrupt (because they are disabled), but _start() sees that the DMA is stopped, so it starts it. The problem is that it sends the transaction that has just finished again, because pl330_update() hasn't mark it as done yet. This patch fixes this race condition by not calling _start() if the DMA is already executing transactions. When interrupts are reenabled, pl330_update() will call _start(). Reference: <1317892206-3600-1-git-send-email-javi.merino@arm.com> Signed-off-by: Javi Merino <javi.merino@arm.com> Acked-by: Jassi Brar <jassi.brar@samsung.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/common')
-rw-r--r--arch/arm/common/pl330.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm/common/pl330.c b/arch/arm/common/pl330.c
index 97912fa48782..7129cfbdacd6 100644
--- a/arch/arm/common/pl330.c
+++ b/arch/arm/common/pl330.c
@@ -1546,7 +1546,7 @@ int pl330_chan_ctrl(void *ch_id, enum pl330_chan_op op)
/* Start the next */
case PL330_OP_START:
- if (!_start(thrd))
+ if (!_thrd_active(thrd) && !_start(thrd))
ret = -EIO;
break;