diff mbox series

mm/memcg: remove return value of mem_cgroup_scan_tasks()

Message ID 20230616021955.872413-1-zhangpeng362@huawei.com (mailing list archive)
State New
Headers show
Series mm/memcg: remove return value of mem_cgroup_scan_tasks() | expand

Commit Message

Peng Zhang June 16, 2023, 2:19 a.m. UTC 
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>
---
 include/linux/memcontrol.h | 6 +++---
 mm/memcontrol.c            | 9 ++++-----
 2 files changed, 7 insertions(+), 8 deletions(-)

Comments

kernel test robot June 16, 2023, 5:13 a.m. UTC | #1 
Hi Peng,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]

url:    https://github.com/intel-lab-lkp/linux/commits/Peng-Zhang/mm-memcg-remove-return-value-of-mem_cgroup_scan_tasks/20230616-102145
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20230616021955.872413-1-zhangpeng362%40huawei.com
patch subject: [PATCH] mm/memcg: remove return value of mem_cgroup_scan_tasks()
config: x86_64-randconfig-r005-20230616 (https://download.01.org/0day-ci/archive/20230616/202306161306.9YKbncNT-lkp@intel.com/config)
compiler: clang version 15.0.7 (https://github.com/llvm/llvm-project.git 8dfdcc7b7bf66834a761bd8de445840ef68e4d1a)
reproduce (this is a W=1 build):
        mkdir -p ~/bin
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        git remote add akpm-mm https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git
        git fetch akpm-mm mm-everything
        git checkout akpm-mm/mm-everything
        b4 shazam https://lore.kernel.org/r/20230616021955.872413-1-zhangpeng362@huawei.com
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=x86_64 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=x86_64 prepare

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202306161306.9YKbncNT-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from arch/x86/kernel/asm-offsets.c:14:
   In file included from include/linux/suspend.h:5:
   In file included from include/linux/swap.h:9:
>> include/linux/memcontrol.h:1370:2: error: void function 'mem_cgroup_scan_tasks' should not return a value [-Wreturn-type]
           return 0;
           ^      ~
   1 error generated.
   make[2]: *** [scripts/Makefile.build:114: arch/x86/kernel/asm-offsets.s] Error 1 shuffle=3878817758
   make[2]: Target 'prepare' not remade because of errors.
   make[1]: *** [Makefile:1287: prepare0] Error 2 shuffle=3878817758
   make[1]: Target 'prepare' not remade because of errors.
   make: *** [Makefile:226: __sub-make] Error 2 shuffle=3878817758
   make: Target 'prepare' not remade because of errors.


vim +/mem_cgroup_scan_tasks +1370 include/linux/memcontrol.h

5660048ccac873 Johannes Weiner  2012-01-12  1366  
5044a2e0ddbf82 ZhangPeng        2023-06-16  1367  static inline void mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
7c5f64f84483bd Vladimir Davydov 2016-10-07  1368  		int (*fn)(struct task_struct *, void *), void *arg)
7c5f64f84483bd Vladimir Davydov 2016-10-07  1369  {
7c5f64f84483bd Vladimir Davydov 2016-10-07 @1370  	return 0;
7c5f64f84483bd Vladimir Davydov 2016-10-07  1371  }
7c5f64f84483bd Vladimir Davydov 2016-10-07  1372
Peng Zhang June 16, 2023, 6:10 a.m. UTC | #2 
On 2023/6/16 13:13, kernel test robot wrote:

> Hi Peng,
>
> kernel test robot noticed the following build errors:
>
> [auto build test ERROR on akpm-mm/mm-everything]
>
> url:    https://github.com/intel-lab-lkp/linux/commits/Peng-Zhang/mm-memcg-remove-return-value-of-mem_cgroup_scan_tasks/20230616-102145
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
> patch link:    https://lore.kernel.org/r/20230616021955.872413-1-zhangpeng362%40huawei.com
> patch subject: [PATCH] mm/memcg: remove return value of mem_cgroup_scan_tasks()
> config: x86_64-randconfig-r005-20230616 (https://download.01.org/0day-ci/archive/20230616/202306161306.9YKbncNT-lkp@intel.com/config)
> compiler: clang version 15.0.7 (https://github.com/llvm/llvm-project.git 8dfdcc7b7bf66834a761bd8de445840ef68e4d1a)
> reproduce (this is a W=1 build):
>          mkdir -p ~/bin
>          wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>          chmod +x ~/bin/make.cross
>          git remote add akpm-mm https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git
>          git fetch akpm-mm mm-everything
>          git checkout akpm-mm/mm-everything
>          b4 shazam https://lore.kernel.org/r/20230616021955.872413-1-zhangpeng362@huawei.com
>          # save the config file
>          mkdir build_dir && cp config build_dir/.config
>          COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=x86_64 olddefconfig
>          COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=x86_64 prepare
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202306161306.9YKbncNT-lkp@intel.com/
>
> All errors (new ones prefixed by >>):
>
>     In file included from arch/x86/kernel/asm-offsets.c:14:
>     In file included from include/linux/suspend.h:5:
>     In file included from include/linux/swap.h:9:
>>> include/linux/memcontrol.h:1370:2: error: void function 'mem_cgroup_scan_tasks' should not return a value [-Wreturn-type]
>             return 0;

Thanks for reporting. I'll drop this line.

>             ^      ~
>     1 error generated.
>     make[2]: *** [scripts/Makefile.build:114: arch/x86/kernel/asm-offsets.s] Error 1 shuffle=3878817758
>     make[2]: Target 'prepare' not remade because of errors.
>     make[1]: *** [Makefile:1287: prepare0] Error 2 shuffle=3878817758
>     make[1]: Target 'prepare' not remade because of errors.
>     make: *** [Makefile:226: __sub-make] Error 2 shuffle=3878817758
>     make: Target 'prepare' not remade because of errors.
>
>
> vim +/mem_cgroup_scan_tasks +1370 include/linux/memcontrol.h
>
> 5660048ccac873 Johannes Weiner  2012-01-12  1366
> 5044a2e0ddbf82 ZhangPeng        2023-06-16  1367  static inline void mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
> 7c5f64f84483bd Vladimir Davydov 2016-10-07  1368  		int (*fn)(struct task_struct *, void *), void *arg)
> 7c5f64f84483bd Vladimir Davydov 2016-10-07  1369  {
> 7c5f64f84483bd Vladimir Davydov 2016-10-07 @1370  	return 0;
> 7c5f64f84483bd Vladimir Davydov 2016-10-07  1371  }
> 7c5f64f84483bd Vladimir Davydov 2016-10-07  1372
>
diff mbox series

Patch

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 7738d8c0fa4f..c20375a77c07 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)
 {
@@ -1366,7 +1366,7 @@  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;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 0fe39ed857db..92a553b06f7a 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