cpuset: fix the return value of cpuset_write_u64()

commit a903f0865a190f8778c73df1a810ea6e25e5d7cf upstream.

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>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 64b3f791bbe5..6948e9476b42 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -1502,11 +1502,13 @@ 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: