[PATCH] 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 <redacted>
---
 net/sched/cls_cgroup.c |    6 ------
 1 files changed, 0 insertions(+), 6 deletions(-)

diff --git a/net/sched/cls_cgroup.c b/net/sched/cls_cgroup.c
index 91a3db4..1ab4542 100644
--- 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;
 }
 

-- 
1.5.4.rc3

On Wed, Mar 11, 2009 at 6:47 PM, Li Zefan [off-list ref] wrote:

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.

There's no guarantee that the group isn't dead, so we could be writing
into a value that's never going to be used again, but I guess that's
not really a big deal.

Acked-by: Paul Menage <redacted>