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

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

[Stephen Rothwell]

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Hi all,

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

mm/memcontrol.c: In function 'mem_cgroup_get_from_ino':
mm/memcontrol.c:5114:24: error: returning 'long int' from a function with return type 'struct mem_cgroup *' makes pointer from integer without a cast [-Werror=int-conversion]
 5114 |                 return PTR_ERR(cgrp);
      |                        ^~~~~~~~~~~~~

Caused by commit

  fa7e439cf90b ("cgroup: Homogenize cgroup_get_from_id() return value")

I have used the cgroup tree from next-20220826 for today.

-- 
Cheers,
Stephen Rothwell

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[PATCH] cgroup: Fix build failure when CONFIG_SHRINKER_DEBUG

[Tejun Heo]

From c0f2df49cf2471289d5aabf16f50ac26eb268f7d Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Sun, 28 Aug 2022 17:54:15 -1000
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

fa7e439cf90b ("cgroup: Homogenize cgroup_get_from_id() return value") broken
build when CONFIG_SHRINKER_DEBUG by trying to return an errno from
mem_cgroup_get_from_ino() which returns struct mem_cgroup *. Fix by using
ERR_CAST() instead.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Michal Koutný <mkoutny@suse.com>f
Fixes: fa7e439cf90b ("cgroup: Homogenize cgroup_get_from_id() return value")
---
Sorry about that. Applied this fix to cgroup/for-6.1.

Thanks.

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

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 86f5ca8c6fa6..e9fc364d5e96 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5111,7 +5111,7 @@ struct mem_cgroup *mem_cgroup_get_from_ino(unsigned long ino)
 
 	cgrp = cgroup_get_from_id(ino);
 	if (IS_ERR(cgrp))
-		return PTR_ERR(cgrp);
+		return ERR_CAST(cgrp);
 
 	css = cgroup_get_e_css(cgrp, &memory_cgrp_subsys);
 	if (css)
-- 
2.37.2