From: NeilBrown <neilb@suse.de>
Date: Tue, 13 Mar 2012 00:21:20 +0000 (+1100)
Subject: md/raid10: remove unnecessary smp_mb() from end_sync_write
X-Git-Tag: v3.4-rc1~147^2~20
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=547414d19fd72376ff2ecc42aac8d7a051f03d26;p=pandora-kernel.git

md/raid10: remove unnecessary smp_mb() from end_sync_write

Recent commit 4ca40c2ce099e4f1ce3 (md/raid10: Allow replacement device ...)
added an smp_mb in end_sync_write.
This was to close a possible race with raid10_remove_disk.
However there is no such race as it is never attempted to remove a
disk while resync (or recovery) is happening.
so the smp_mb is just noise.

Signed-off-by: NeilBrown <neilb@suse.de>
---

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 58c44d6453a0..1a19c962f860 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1682,10 +1682,8 @@ static void end_sync_write(struct bio *bio, int error)
 	d = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
 	if (repl)
 		rdev = conf->mirrors[d].replacement;
-	if (!rdev) {
-		smp_mb();
+	else
 		rdev = conf->mirrors[d].rdev;
-	}
 
 	if (!uptodate) {
 		if (repl)