Commit 9ca641b0 authored by Brian Norris's avatar Brian Norris

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

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 6b0d9a84 ("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: 72ea4036 ("mtd: nand: added nand_shutdown")
Reported-by: default avatarAndrew E. Mileski <andrewm@isoar.ca>
Signed-off-by: default avatarBrian Norris <computersforpeace@gmail.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: Andrew E. Mileski <andrewm@isoar.ca>
Acked-by: default avatarScott Branden <sbranden@broadcom.com>
Reviewed-by: default avatarBoris Brezillon <boris.brezillon@free-electrons.com>
parent 96dd922c
...@@ -3110,7 +3110,7 @@ static void nand_resume(struct mtd_info *mtd) ...@@ -3110,7 +3110,7 @@ static void nand_resume(struct mtd_info *mtd)
*/ */
static void nand_shutdown(struct mtd_info *mtd) static void nand_shutdown(struct mtd_info *mtd)
{ {
nand_get_device(mtd, FL_SHUTDOWN); nand_get_device(mtd, FL_PM_SUSPENDED);
} }
/* Set default functions */ /* Set default functions */
......
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