From: NeilBrown <neilb@cse.unsw.edu.au>
Date: Fri, 9 Sep 2005 23:23:57 +0000 (-0700)
Subject: [PATCH] md: ensure bitmap_writeback_daemon handles shutdown properly.
X-Git-Tag: v2.6.14-rc1~235
X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=9ba00538ada7ecb4fb8bd71ba734a8eada987817;p=linux-2.6-omap-h63xx.git

[PATCH] md: ensure bitmap_writeback_daemon handles shutdown properly.

mddev->bitmap gets clearred before the writeback daemon is stopped.  So the
write_back daemon needs to be careful not to dereference the 'bitmap' if it is
NULL.

Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 90fe70d76a3..87145faac49 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -1156,6 +1156,9 @@ static void bitmap_writeback_daemon(mddev_t *mddev)
 		err = -EINTR;
 		goto out;
 	}
+	if (bitmap == NULL)
+		/* about to be stopped. */
+		return;
 
 	PRINTK("%s: bitmap writeback daemon woke up...\n", bmname(bitmap));
 	/* wait on bitmap page writebacks */