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>

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 18f14a2..8d0ead9 100644 (file)
--- 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;
 }