cpuset: fix the return value of cpuset_write_u64()

Writing to this file always returns -ENODEV:

  # echo 1 > cpuset.memory_pressure_enabled
  -bash: echo: write error: No such device

Signed-off-by: Li Zefan <lizefan@huawei.com>
Cc: <stable@vger.kernel.org> # 3.9+
Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index e5657788feddfefaaed5f7ce3ce2ac26ca80a9c1..010a0083c0ae4cfa222e2d51f2e951893bac28c4 100644 (file)
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -1608,11 +1608,13 @@ static int cpuset_write_u64(struct cgroup *cgrp, struct cftype *cft, u64 val)
 {
        struct cpuset *cs = cgroup_cs(cgrp);
        cpuset_filetype_t type = cft->private;
-       int retval = -ENODEV;
+       int retval = 0;
 
        mutex_lock(&cpuset_mutex);
-       if (!is_cpuset_online(cs))
+       if (!is_cpuset_online(cs)) {
+               retval = -ENODEV;
                goto out_unlock;
+       }
 
        switch (type) {
        case FILE_CPU_EXCLUSIVE: