bcache: explicitly destroy mutex while exiting

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@gmail.com>
Reviewed-by: Michael Lyle <mlyle@lyle.org>
Reviewed-by: Coly Li <colyli@suse.de>
Reviewed-by: Eric Wheeler <bcache@linux.ewheeler.net>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 46134c45c6f693ae47b69080d5e9eadc6b295e00..b4d28928dec59ac0fa5c531abe8ca3339d82c34b 100644 (file)
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -2095,6 +2095,7 @@ 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)
@@ -2113,14 +2114,15 @@ 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;