From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pa0-x232.google.com ([2607:f8b0:400e:c03::232]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZvwxQ-000328-Cc for linux-mtd@lists.infradead.org; Tue, 10 Nov 2015 00:38:45 +0000 Received: by pacdm15 with SMTP id dm15so191263099pac.3 for ; Mon, 09 Nov 2015 16:38:23 -0800 (PST) From: Brian Norris To: Cc: Brian Norris , Boris Brezillon , Richard Weinberger , Ray Jui , Ezequiel Garcia , Scott Branden , "Andrew E . Mileski" Subject: [PATCH] mtd: nand: fix shutdown/reboot for multi-chip systems Date: Mon, 9 Nov 2015 16:37:28 -0800 Message-Id: <1447115848-92621-1-git-send-email-computersforpeace@gmail.com> List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 Signed-off-by: Brian Norris Cc: Scott Branden Cc: Andrew E. Mileski --- I only compile-tested If we get proper tests, this is probably 4.4 material drivers/mtd/nand/nand_base.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index cc74142938b0..ece544efccc3 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -3110,7 +3110,7 @@ static void nand_resume(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 */ -- 2.6.0.rc2.230.g3dd15c0