2020-12-24 13:27:14

by Zheng Yongjun

Subject: [PATCH v2 -next] md: bcache: 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/md/bcache/super.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 46a00134a36a..963d62a15f37 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -40,7 +40,7 @@ static const char invalid_uuid[] = {
};

static struct kobject *bcache_kobj;
-struct mutex bch_register_lock;
+DEFINE_MUTEX(bch_register_lock);
bool bcache_is_reboot;
LIST_HEAD(bch_cache_sets);
static LIST_HEAD(uncached_devices);
@@ -2832,7 +2832,6 @@ static int __init bcache_init(void)

check_module_parameters();

- mutex_init(&bch_register_lock);
init_waitqueue_head(&unregister_wait);
register_reboot_notifier(&reboot);

--
2.22.0

2020-12-24 14:49:36

by Coly Li

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

On 12/24/20 9:24 PM, 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]>

NACK. For this case, it is unnecessary to initialize a global variable
so early in declaration, this change makes bcache.ko bigger and I don't
see any benefit.

Coly Li

> ---
> drivers/md/bcache/super.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
> index 46a00134a36a..963d62a15f37 100644
> --- a/drivers/md/bcache/super.c
> +++ b/drivers/md/bcache/super.c
> @@ -40,7 +40,7 @@ static const char invalid_uuid[] = {
> };
>
> static struct kobject *bcache_kobj;
> -struct mutex bch_register_lock;
> +DEFINE_MUTEX(bch_register_lock);
> bool bcache_is_reboot;
> LIST_HEAD(bch_cache_sets);
> static LIST_HEAD(uncached_devices);
> @@ -2832,7 +2832,6 @@ static int __init bcache_init(void)
>
> check_module_parameters();
>
> - mutex_init(&bch_register_lock);
> init_waitqueue_head(&unregister_wait);
> register_reboot_notifier(&reboot);
>
>