linux-fbdev.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH -next] backlight: backlight: Use DEFINE_MUTEX() for mutex lock
@ 2021-04-05 10:14 Zheng Yongjun
  2021-04-06  8:51 ` Daniel Thompson
  0 siblings, 1 reply; 2+ messages in thread
From: Zheng Yongjun @ 2021-04-05 10:14 UTC (permalink / raw)
  To: zhengyongjun3, Lee Jones, Daniel Thompson, Jingoo Han
  Cc: dri-devel, linux-fbdev, kernel-janitors, Hulk Robot

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

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com>
---
 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;


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH -next] backlight: backlight: Use DEFINE_MUTEX() for mutex lock
  2021-04-05 10:14 [PATCH -next] backlight: backlight: Use DEFINE_MUTEX() for mutex lock Zheng Yongjun
@ 2021-04-06  8:51 ` Daniel Thompson
  0 siblings, 0 replies; 2+ messages in thread
From: Daniel Thompson @ 2021-04-06  8:51 UTC (permalink / raw)
  To: Zheng Yongjun
  Cc: Lee Jones, Jingoo Han, dri-devel, linux-fbdev, kernel-janitors,
	Hulk Robot

On Mon, Apr 05, 2021 at 06:14:40PM +0800, Zheng Yongjun wrote:
> mutex lock can be initialized automatically with DEFINE_MUTEX()
> rather than explicitly calling mutex_init().
> 
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com>

This patch looks like a resend of this one (but with a different revision
number):
https://lkml.org/lkml/2020/12/24/229

A resend should always maintain the version number and be clearly marked
as a resend.  In this case, there is also a pending review comment that
you have ignored.  Given I also clarified when you asked (off-list) for
additional details I'm very surprised to see this patch circulated again
without modification.

I have repeated the feedback below.


> ---
>  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);

On Mon, 4 Jan 2021 at 14:19, Daniel Thompson wrote:
: the purpose of backlight_dev_list_mutex is (as the name suggests) to
: protect backlight_dev_list. It makes no sense to initialize these
: variables from different places within the code. It just makes it
: harder to reason about the lifetimes of the variables.
:
: To be clear, switching over to static initializers is a good change,
: but please change all three in one patch.


Daniel.

^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2021-04-06  8:51 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-04-05 10:14 [PATCH -next] backlight: backlight: Use DEFINE_MUTEX() for mutex lock Zheng Yongjun
2021-04-06  8:51 ` Daniel Thompson

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).