bcache: allows use of register in udev to avoid "device_busy" error.

Allows to use register, not register_quiet in udev to avoid "device_busy" error.
The initial patch proposed at https://lkml.org/lkml/2013/8/26/549 by Gabriel de Perthuis
<g2p.code@gmail.com> does not unlock the mutex and hangs the kernel.

See http://thread.gmane.org/gmane.linux.kernel.bcache.devel/2594 for the discussion.

Cc: Denis Bychkov <manover@gmail.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Eric Wheeler <bcache@linux.ewheeler.net>
Cc: Gabriel de Perthuis <g2p.code@gmail.com>
Cc: stable@vger.kernel.org

Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 18f14a246d70..8d0ead98eb6e 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1938,6 +1938,8 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
                         else
                                 err = "device busy";
                         mutex_unlock(&bch_register_lock);
+                        if (attr == &ksysfs_register_quiet)
+                                goto out;
                 }
                 goto err;
         }
@@ -1976,8 +1978,7 @@ out:
 err_close:
         blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
 err:
-        if (attr != &ksysfs_register_quiet)
-                pr_info("error opening %s: %s", path, err);
+        pr_info("error opening %s: %s", path, err);
         ret = -EINVAL;
         goto out;
 }