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From:   Peng Zhang <zhangpeng362@huawei.com>
To:     <linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>
CC:     <hannes@cmpxchg.org>, <mhocko@kernel.org>,
        <roman.gushchin@linux.dev>, <shakeelb@google.com>,
        <muchun.song@linux.dev>, <akpm@linux-foundation.org>,
        <wangkefeng.wang@huawei.com>, <sunnanyong@huawei.com>,
        ZhangPeng <zhangpeng362@huawei.com>
Subject: [PATCH v2] mm/memcg: remove return value of mem_cgroup_scan_tasks()
Date:   Fri, 16 Jun 2023 14:30:30 +0800
Message-ID: <20230616063030.977586-1-zhangpeng362@huawei.com>
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From: ZhangPeng <zhangpeng362@huawei.com>

No user checks the return value of mem_cgroup_scan_tasks(). Make the
return value void.

Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
---
v2:
- drop redundant return 0 per kernel test robot

 include/linux/memcontrol.h | 7 +++----
 mm/memcontrol.c            | 9 ++++-----
 2 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index c3d3a0c09315..5818af8eca5a 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -820,8 +820,8 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *,
 				   struct mem_cgroup *,
 				   struct mem_cgroup_reclaim_cookie *);
 void mem_cgroup_iter_break(struct mem_cgroup *, struct mem_cgroup *);
-int mem_cgroup_scan_tasks(struct mem_cgroup *,
-			  int (*)(struct task_struct *, void *), void *);
+void mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
+			   int (*)(struct task_struct *, void *), void *arg);
 
 static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
 {
@@ -1364,10 +1364,9 @@ static inline void mem_cgroup_iter_break(struct mem_cgroup *root,
 {
 }
 
-static inline int mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
+static inline void mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
 		int (*fn)(struct task_struct *, void *), void *arg)
 {
-	return 0;
 }
 
 static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index cf06b1c9b3bb..a834b1edcde9 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1259,13 +1259,13 @@ static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
  *
  * This function iterates over tasks attached to @memcg or to any of its
  * descendants and calls @fn for each task. If @fn returns a non-zero
- * value, the function breaks the iteration loop and returns the value.
- * Otherwise, it will iterate over all tasks and return 0.
+ * value, the function breaks the iteration loop. Otherwise, it will iterate
+ * over all tasks and return 0.
  *
  * This function must not be called for the root memory cgroup.
  */
-int mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
-			  int (*fn)(struct task_struct *, void *), void *arg)
+void mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
+			   int (*fn)(struct task_struct *, void *), void *arg)
 {
 	struct mem_cgroup *iter;
 	int ret = 0;
@@ -1285,7 +1285,6 @@ int mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
 			break;
 		}
 	}
-	return ret;
 }
 
 #ifdef CONFIG_DEBUG_VM
-- 
2.25.1