Re: [PATCH v2] bcache: explicitly destroy mutex while exiting

From: Coly Li
Date: Tue Oct 10 2017 - 08:26:10 EST


On 2017/10/10 äå5:00, Liang Chen wrote:
> mutex_destroy does nothing most of time, but it's better to call
> it to make the code future proof and it also has some meaning
> for like mutex debug.
>
> As Coly pointed out in a previous review, bcache_exit() may not be
> able to handle all the references properly if userspace registers
> cache and backing devices right before bch_debug_init runs and
> bch_debug_init failes later. So not exposing userspace interface
> until everything is ready to avoid that issue.
>
> Signed-off-by: Liang Chen <liangchen.linux@xxxxxxxxx>

Hi Liang,

No more comment from me, it looks good. Thanks.

Reviewed-by: Coly Li <colyli@xxxxxxx>

> ---
> drivers/md/bcache/super.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
> index fc0a31b..25bf003 100644
> --- a/drivers/md/bcache/super.c
> +++ b/drivers/md/bcache/super.c
> @@ -2085,6 +2085,7 @@ static void bcache_exit(void)
> if (bcache_major)
> unregister_blkdev(bcache_major, "bcache");
> unregister_reboot_notifier(&reboot);
> + mutex_destroy(&bch_register_lock);
> }
>
> static int __init bcache_init(void)
> @@ -2103,14 +2104,15 @@ static int __init bcache_init(void)
> bcache_major = register_blkdev(0, "bcache");
> if (bcache_major < 0) {
> unregister_reboot_notifier(&reboot);
> + mutex_destroy(&bch_register_lock);
> return bcache_major;
> }
>
> if (!(bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0)) ||
> !(bcache_kobj = kobject_create_and_add("bcache", fs_kobj)) ||
> - sysfs_create_files(bcache_kobj, files) ||
> bch_request_init() ||
> - bch_debug_init(bcache_kobj))
> + bch_debug_init(bcache_kobj) ||
> + sysfs_create_files(bcache_kobj, files))
> goto err;
>
> return 0;
>


--
Coly Li