[PATCH 5/9] pid: Update pid_vnr to use task_active_pid_ns

Pavel Emelyanov xemul at openvz.org
Wed Dec 12 05:28:33 PST 2007


Eric W. Biederman wrote:
> There is no real additional cost in using task_active_pid_ns and
> by doing so it means we do not need to audit the callers of pid_vnr
> closely, to ensure they are always called on living processes.
> 
> Signed-off-by: Eric W. Biederman <ebiederm at xmission.com>
> ---
>  kernel/pid.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/kernel/pid.c b/kernel/pid.c
> index 54d7634..a7ecfce 100644
> --- a/kernel/pid.c
> +++ b/kernel/pid.c
> @@ -444,7 +444,7 @@ pid_t pid_nr_ns(struct pid *pid, struct pid_namespace *ns)
>  
>  pid_t pid_vnr(struct pid *pid)
>  {
> -	return pid_nr_ns(pid, current->nsproxy->pid_ns);
> +	return pid_nr_ns(pid, task_active_pid_ns(current));

NAK. Your version will make more dereferences and one
condition check (if (pid != NULL)). Besides, dead process
can never call this thing - it is even never scheduled 
for execution.

>  }
>  EXPORT_SYMBOL_GPL(pid_vnr);
>  



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