cls_cgroup: remove unneeded cgroup_lock

We can remove this lock here, since we are in cgroup write handler and
thus the cgrp is guaranteed to be valid, and no lock is needed when
writing a u32 variable.

Signed-off-by: Li Zefan <lizf@cn.fujitsuc.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/cls_cgroup.c b/net/sched/cls_cgroup.c
index 91a3db4..1ab4542 100644 (file)
--- a/net/sched/cls_cgroup.c
+++ b/net/sched/cls_cgroup.c
@@ -62,13 +62,7 @@ static u64 read_classid(struct cgroup *cgrp, struct cftype *cft)
 
 static int write_classid(struct cgroup *cgrp, struct cftype *cft, u64 value)
 {
-       if (!cgroup_lock_live_group(cgrp))
-               return -ENODEV;
-
        cgrp_cls_state(cgrp)->classid = (u32) value;
-
-       cgroup_unlock();
-
        return 0;
 }