2020-12-24 13:28:46

by Zheng Yongjun

Subject: [PATCH v2 -next] video: backlight: use DEFINE_MUTEX() for mutex lock

mutex lock can be initialized automatically with DEFINE_MUTEX()
rather than explicitly calling mutex_init().

Signed-off-by: Zheng Yongjun <[email protected]>
---
drivers/video/backlight/backlight.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c
index 537fe1b376ad..d7a09c422547 100644
--- a/drivers/video/backlight/backlight.c
+++ b/drivers/video/backlight/backlight.c
@@ -64,7 +64,7 @@
*/

static struct list_head backlight_dev_list;
-static struct mutex backlight_dev_list_mutex;
+static DEFINE_MUTEX(backlight_dev_list_mutex);
static struct blocking_notifier_head backlight_notifier;

static const char *const backlight_types[] = {
@@ -757,7 +757,6 @@ static int __init backlight_class_init(void)
backlight_class->dev_groups = bl_device_groups;
backlight_class->pm = &backlight_class_dev_pm_ops;
INIT_LIST_HEAD(&backlight_dev_list);
- mutex_init(&backlight_dev_list_mutex);
BLOCKING_INIT_NOTIFIER_HEAD(&backlight_notifier);

return 0;
--
2.22.0

2021-01-04 10:49:18

by Daniel Thompson

Subject: Re: [PATCH v2 -next] video: backlight: use DEFINE_MUTEX() for mutex lock

On Thu, Dec 24, 2020 at 09:26:01PM +0800, Zheng Yongjun wrote:
> mutex lock can be initialized automatically with DEFINE_MUTEX()
> rather than explicitly calling mutex_init().
>
> Signed-off-by: Zheng Yongjun <[email protected]>
> ---
> drivers/video/backlight/backlight.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c
> index 537fe1b376ad..d7a09c422547 100644
> --- a/drivers/video/backlight/backlight.c
> +++ b/drivers/video/backlight/backlight.c
> @@ -64,7 +64,7 @@
> */
>
> static struct list_head backlight_dev_list;
> -static struct mutex backlight_dev_list_mutex;
> +static DEFINE_MUTEX(backlight_dev_list_mutex);
> static struct blocking_notifier_head backlight_notifier;

Why do we want to convert one of these variables to use a
static initializers but leave the other two unchanged? Surely they
should all be changed.


Daniel.


>
> static const char *const backlight_types[] = {
> @@ -757,7 +757,6 @@ static int __init backlight_class_init(void)
> backlight_class->dev_groups = bl_device_groups;
> backlight_class->pm = &backlight_class_dev_pm_ops;
> INIT_LIST_HEAD(&backlight_dev_list);
> - mutex_init(&backlight_dev_list_mutex);
> BLOCKING_INIT_NOTIFIER_HEAD(&backlight_notifier);
>
> return 0;
> --
> 2.22.0
>