Patch "mtd: nand: fix shutdown/reboot for multi-chip systems" has been added to the 4.3-stable tree

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

mtd: nand: fix shutdown/reboot for multi-chip systems

to the 4.3-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:
mtd-nand-fix-shutdown-reboot-for-multi-chip-systems.patch
and it can be found in the queue-4.3 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Brian Norris <[email protected]>
Date: Mon, 9 Nov 2015 16:37:28 -0800
Subject: mtd: nand: fix shutdown/reboot for multi-chip systems

From: Brian Norris <[email protected]>

commit 9ca641b0f02a3a1eedbc8c296e695326da9bbaf9 upstream.

If multiple NAND chips are registered to the same controller, then when rebooting the system, the first one will grab the controller lock, while the second will wait forever for the first one to release it. i.e., a classic deadlock.

This problem was solved for a similar case (suspend/resume) back in commit 6b0d9a841249 ("mtd: nand: fix multi-chip suspend problem"), and the shutdown state really isn't much different for us, so rather than adding a new special case to nand_get_device(), we can just overload the FL_PM_SUSPENDED state.

Now, multiple chips can "get" the same controller lock (preventing further I/O), while we still allow other chips to pass through nand_shutdown().

Original report:
http://thread.gmane.org/gmane.linux.drivers.mtd/59726
http://lists.infradead.org/pipermail/linux-mtd/2015-July/059992.html

---
 drivers/mtd/nand/nand_base.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -2964,7 +2964,7 @@ static void nand_resume(struct mtd_info
  */
 static void nand_shutdown(struct mtd_info *mtd)
 {
-	nand_get_device(mtd, FL_SHUTDOWN);
+	nand_get_device(mtd, FL_PM_SUSPENDED);
 }
 
 /* Set default functions */

Patches currently in stable-queue which might be from [email protected] are

queue-4.3/mtd-mtdpart-fix-add_mtd_partitions-error-path.patch queue-4.3/mtd-blkdevs-fix-potential-deadlock-lockdep-warnings.patch queue-4.3/mtd-nand-fix-shutdown-reboot-for-multi-chip-systems.patch queue-4.3/mtd-jz4740_nand-fix-build-on-jz4740-after-removing-gpio.h.patch