Patch "bcache: allows use of register in udev to avoid "device_busy" error." has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

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

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     bcache-allows-use-of-register-in-udev-to-avoid-device_busy-error.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From d7076f21629f8f329bca4a44dc408d94670f49e2 Mon Sep 17 00:00:00 2001
From: Gabriel de Perthuis <g2p.code@gmail.com>
Date: Sun, 29 Nov 2015 18:40:23 -0800
Subject: bcache: allows use of register in udev to avoid "device_busy" error.

From: Gabriel de Perthuis <g2p.code@gmail.com>

commit d7076f21629f8f329bca4a44dc408d94670f49e2 upstream.

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>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/md/bcache/super.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1938,6 +1938,8 @@ static ssize_t register_bcache(struct ko
 			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;
 }


Patches currently in stable-queue which might be from g2p.code@gmail.com are

queue-4.4/bcache-allows-use-of-register-in-udev-to-avoid-device_busy-error.patch