Re: [PATCH 09/11] epoll: Remove unnecessary error path

From: Eric Wong
Date: Mon Sep 30 2013 - 16:59:19 EST


Andi Kleen <andi@xxxxxxxxxxxxxx> wrote:
> From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
>
> A static checker was pointing out that nothing can possible set
> nwait < 0 in this path. The comment and the check appears to be
> outdated. Remove it.

I don't think so...

> Cc: viro@xxxxxxxxxxxxxxxxxx
> Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> ---
> fs/eventpoll.c | 10 ----------
> 1 file changed, 10 deletions(-)
>
> diff --git a/fs/eventpoll.c b/fs/eventpoll.c
> index 473e09d..f72bf55 100644
> --- a/fs/eventpoll.c
> +++ b/fs/eventpoll.c
> @@ -1276,15 +1276,6 @@ static int ep_insert(struct eventpoll *ep, struct epoll_event *event,
> */
> revents = ep_item_poll(epi, &epq.pt);

ep_item_poll calls f_op->poll, which calls poll_wait().
poll_wait() will call ep_ptable_queue_proc.

> - /*
> - * We have to check if something went wrong during the poll wait queue
> - * install process. Namely an allocation for a wait queue failed due
> - * high memory pressure.
> - */
> - error = -ENOMEM;
> - if (epi->nwait < 0)
> - goto error_unregister;
> -
> /* Add the current item to the list of active epoll hook for this file */
> spin_lock(&tfile->f_lock);
> list_add_tail(&epi->fllink, &tfile->f_ep_links);
> @@ -1334,7 +1325,6 @@ error_remove_epi:
>
> rb_erase(&epi->rbn, &ep->rbr);
>
> -error_unregister:
> ep_unregister_pollwait(ep, epi);
>
> /*
--
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