Re: [PATCH] pidns: remove recursion from free_pid_ns (v2)

From: Oleg Nesterov
Date: Sat Oct 06 2012 - 15:12:19 EST


On 10/06, Andrew Vagin wrote:
>
> --- a/kernel/pid_namespace.c
> +++ b/kernel/pid_namespace.c
> @@ -138,11 +138,20 @@ void free_pid_ns(struct kref *kref)
>
> ns = container_of(kref, struct pid_namespace, kref);
>
> - parent = ns->parent;
> - destroy_pid_namespace(ns);
> + while (1) {
>
> - if (parent != NULL)
> - put_pid_ns(parent);
> + parent = ns->parent;
> + destroy_pid_namespace(ns);
> +
> + if (parent == &init_pid_ns)
> + break;
> +
> + /* kref_put cannot be used for avoiding recursion */
> + if (__kref_put(&parent->kref) == 0)
> + break;
> +
> + ns = parent;
> + }
> }

Reviewed-by: Oleg Nesterov <oleg@xxxxxxxxxx>

But, Andrew... please note that this adds the unnecessary empty
line after "while (1)". The coding style police will complain
anyway, so I'd suggest you to send v3 ;)

Oleg.

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