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SubjectRe: [PATCH] cls_cgroup: remove unneeded cgroup_lock
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On Wed, Mar 11, 2009 at 6:47 PM, Li Zefan <lizf@cn.fujitsu.com> 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 <menage@google.com>

>
> Signed-off-by: Li Zefan <lizf@cn.fujitsuc.com>
> ---
> 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
>
>


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