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| author | Uwe Kleine-König <u.kleine-koenig@pengutronix.de> | 2010-11-24 12:57:14 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-11-25 06:50:47 +0900 |
| commit | d1d73578e053b981c3611e5a211534290d24a5eb (patch) | |
| tree | 3879428554320c30bc3ccfd0b217710e256ca36f | |
| parent | b38eeaae267e4cd385ababcc2df82f6c46fc8633 (diff) | |
| download | linux-d1d73578e053b981c3611e5a211534290d24a5eb.tar.gz linux-d1d73578e053b981c3611e5a211534290d24a5eb.tar.bz2 linux-d1d73578e053b981c3611e5a211534290d24a5eb.zip | |
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.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c index e207810bba3c..08703299ef61 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; } |