[PATCH] Fix ppc64 smu driver locking
The SMU driver has a small mistake in the locking of the interrupt code,
if polled access and interrupt access race, interrupt may take a lock
and return without releasing it. This fixes it. With that patch, the
driver is rock solid with my experimental thermal control (which bangs
it pretty hard) racing with real time clock and cpufreq handling.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/macintosh/smu.c b/drivers/macintosh/smu.c
index a85ac18..9b38674 100644
--- a/drivers/macintosh/smu.c
+++ b/drivers/macintosh/smu.c
@@ -153,8 +153,10 @@
spin_lock_irqsave(&smu->lock, flags);
gpio = pmac_do_feature_call(PMAC_FTR_READ_GPIO, NULL, smu->doorbell);
- if ((gpio & 7) != 7)
+ if ((gpio & 7) != 7) {
+ spin_unlock_irqrestore(&smu->lock, flags);
return IRQ_HANDLED;
+ }
cmd = smu->cmd_cur;
smu->cmd_cur = NULL;