From cb4b86ba47bb0937b71fb825b3ed88adf7a190f0 Mon Sep 17 00:00:00 2001
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Date: Tue, 16 Jun 2009 15:32:52 -0700
Subject: mm: add swap cache interface for swap reference

In a following patch, the usage of swap cache is recorded into swap_map.
This patch is for necessary interface changes to do that.

2 interfaces:

  - swapcache_prepare()
  - swapcache_free()

are added for allocating/freeing refcnt from swap-cache to existing swap
entries.  But implementation itself is not changed under this patch.  At
adding swapcache_free(), memcg's hook code is moved under
swapcache_free().  This is better than using scattered hooks.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: Balbir Singh <balbir@in.ibm.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 mm/shmem.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'mm/shmem.c')

diff --git a/mm/shmem.c b/mm/shmem.c
index 0132fbd45a2..47ab1918228 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1097,7 +1097,7 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc)
 	shmem_swp_unmap(entry);
 unlock:
 	spin_unlock(&info->lock);
-	swap_free(swap);
+	swapcache_free(swap, NULL);
 redirty:
 	set_page_dirty(page);
 	if (wbc->for_reclaim)
-- 
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