[PATCH] fix swap cluster offset

When we've allocated SWAPFILE_CLUSTER pages, ->cluster_next should be the
first index of swap cluster.  But current code probably sets it wrong offset.

Signed-off-by: Akinobu Mita <mita@miraclelinux.com>
Acked-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 1f9cf0d..365ed6f 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -116,7 +116,7 @@
 				last_in_cluster = offset + SWAPFILE_CLUSTER;
 			else if (offset == last_in_cluster) {
 				spin_lock(&swap_lock);
-				si->cluster_next = offset-SWAPFILE_CLUSTER-1;
+				si->cluster_next = offset-SWAPFILE_CLUSTER+1;
 				goto cluster;
 			}
 			if (unlikely(--latency_ration < 0)) {