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

[<gregkh@linuxfoundation.org>]

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 <stable@vger.kernel.org> know about it.


>From 9ca641b0f02a3a1eedbc8c296e695326da9bbaf9 Mon Sep 17 00:00:00 2001
From: Brian Norris <computersforpeace@gmail.com>
Date: Mon, 9 Nov 2015 16:37:28 -0800
Subject: mtd: nand: fix shutdown/reboot for multi-chip systems

From: Brian Norris <computersforpeace@gmail.com>

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

Fixes: 72ea403669c7 ("mtd: nand: added nand_shutdown")
Reported-by: Andrew E. Mileski <andrewm@isoar.ca>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: Andrew E. Mileski <andrewm@isoar.ca>
Acked-by: Scott Branden <sbranden@broadcom.com>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -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 computersforpeace@gmail.com 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