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SubjectRe: [PATCH] backlight: grab ops_lock before testing bd->ops
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On Mon, 2010-11-22 at 10:43 +0100, Uwe Kleine-König wrote:
> 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.
>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

Acked-by: Richard Purdie <rpurdie@linux.intel.com>

> ---
> 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 e207810..0870329 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;
> }


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