Subject: linux-next: build failure after merge of the cgroup tree

From: Stephen Rothwell <[email-masked]>
Date: Fri, 25 Sep 2015 13:26:00 +1000

Hi Tejun,

After merging the cgroup tree, today's linux-next build (x86_64
allmodconfig) failed like this:

mm/vmscan.c: In function 'sane_reclaim':
mm/vmscan.c:178:2: error: implicit declaration of function 'cgroup_on_dfl' [-Werror=implicit-function-declaration]
  if (cgroup_on_dfl(memcg->css.cgroup))
  ^

Caused by commit

  d5028f9f7d8d ("vmscan: fix sane_reclaim helper for legacy memcg")

from Linus' tree interacting with commit

  9e10a130d9b6 ("cgroup: replace cgroup_on_dfl() tests in controllers with cgroup_subsys_on_dfl()")

from the cgroup tree.

We new this was coming, so I have applied the following merge fix patch from Andrew's tree and can carry it as necessary:

From: Michal Hocko <[email-masked]>
Subject: vmscan build fix

Signed-off-by: Andrew Morton <[email-masked]>
---

 mm/vmscan.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff -puN mm/vmscan.c~vmscan-build-fix mm/vmscan.c
--- a/mm/vmscan.c~vmscan-build-fix
+++ a/mm/vmscan.c
@@ -175,7 +175,7 @@ static bool sane_reclaim(struct scan_con
 	if (!memcg)
 		return true;
 #ifdef CONFIG_CGROUP_WRITEBACK
-	if (cgroup_on_dfl(memcg->css.cgroup))
+	if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
 		return true;
 #endif
 	return false;
_

-- 
Cheers,
Stephen Rothwell                    [email-masked]