[PATCH] md: fix calculation of ->degraded for multipath and raid10

Two less-used md personalities have bugs in the calculation of ->degraded (the
extent to which the array is degraded).

Signed-off-by: Neil Brown <neilb@suse.de>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 1250f0e..74f17a9 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -2079,7 +2079,7 @@
 		disk = conf->mirrors + i;
 
 		if (!disk->rdev ||
-		    !test_bit(In_sync, &rdev->flags)) {
+		    !test_bit(In_sync, &disk->rdev->flags)) {
 			disk->head_position = 0;
 			mddev->degraded++;
 		}