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authorUwe Kleine-König <u.kleine-koenig@pengutronix.de>2010-11-24 12:57:14 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2010-11-25 06:50:47 +0900
commitd1d73578e053b981c3611e5a211534290d24a5eb (patch)
tree3879428554320c30bc3ccfd0b217710e256ca36f
parentb38eeaae267e4cd385ababcc2df82f6c46fc8633 (diff)
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backlight: grab ops_lock before testing bd->ops
According to the comment describing ops_lock in the definition of struct backlight_device and when comparing with other functions in backlight.c the mutex must be hold when checking ops to be non-NULL. Fixes a problem added by c835ee7f4154992e6 ("backlight: Add suspend/resume support to the backlight core") in Jan 2009. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Acked-by: Richard Purdie <rpurdie@linux.intel.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/video/backlight/backlight.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c
index e207810bba3..08703299ef6 100644
--- a/drivers/video/backlight/backlight.c
+++ b/drivers/video/backlight/backlight.c
@@ -197,12 +197,12 @@ static int backlight_suspend(struct device *dev, pm_message_t state)
{
struct backlight_device *bd = to_backlight_device(dev);
- if (bd->ops->options & BL_CORE_SUSPENDRESUME) {
- mutex_lock(&bd->ops_lock);
+ mutex_lock(&bd->ops_lock);
+ if (bd->ops && bd->ops->options & BL_CORE_SUSPENDRESUME) {
bd->props.state |= BL_CORE_SUSPENDED;
backlight_update_status(bd);
- mutex_unlock(&bd->ops_lock);
}
+ mutex_unlock(&bd->ops_lock);
return 0;
}
@@ -211,12 +211,12 @@ static int backlight_resume(struct device *dev)
{
struct backlight_device *bd = to_backlight_device(dev);
- if (bd->ops->options & BL_CORE_SUSPENDRESUME) {
- mutex_lock(&bd->ops_lock);
+ mutex_lock(&bd->ops_lock);
+ if (bd->ops && bd->ops->options & BL_CORE_SUSPENDRESUME) {
bd->props.state &= ~BL_CORE_SUSPENDED;
backlight_update_status(bd);
- mutex_unlock(&bd->ops_lock);
}
+ mutex_unlock(&bd->ops_lock);
return 0;
}