From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B66B5C3527A for ; Fri, 18 Dec 2020 22:03:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8933323B7E for ; Fri, 18 Dec 2020 22:03:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726239AbgLRWC6 (ORCPT ); Fri, 18 Dec 2020 17:02:58 -0500 Received: from mail.kernel.org ([198.145.29.99]:36190 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726252AbgLRWC6 (ORCPT ); Fri, 18 Dec 2020 17:02:58 -0500 Date: Fri, 18 Dec 2020 14:02:03 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1608328924; bh=1wsdQJcMxaNSD6uONJ2u9GA0UyVe8mkcshgkBarFMVE=; h=From:To:Subject:In-Reply-To:From; b=daFverbZ1W7xmDt6cjN5oNNd7axr9utjoDEd91iON7Y0Z1IB0Y7EBtmR0taD8YuJg GXb4O9FO6bNub5PhkfhUbV4oO9a9Od24xtfIQx/ur1dkx43GjckkDkYeLRyvCJjqAb fBbqgmNSreTKn8pi2diQxo98YgBmnaCU0Bi22Bj0= From: Andrew Morton To: akpm@linux-foundation.org, edumazet@google.com, guantaol@google.com, khazhy@google.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, soheil@google.com, torvalds@linux-foundation.org, willemb@google.com Subject: [patch 12/78] epoll: replace gotos with a proper loop Message-ID: <20201218220203.uBS-rg8Is%akpm@linux-foundation.org> In-Reply-To: <20201218140046.497484741326828e5b5d46ec@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Soheil Hassas Yeganeh Subject: epoll: replace gotos with a proper loop The existing loop is pointless, and the labels make it really hard to follow the structure. Replace that control structure with a simple loop that returns when there are new events, there is a signal, or the thread has timed out. Link: https://lkml.kernel.org/r/20201106231635.3528496-8-soheil.kdev@gmail.com Signed-off-by: Soheil Hassas Yeganeh Suggested-by: Linus Torvalds Reviewed-by: Eric Dumazet Reviewed-by: Willem de Bruijn Reviewed-by: Khazhismel Kumykov Cc: Guantao Liu Signed-off-by: Andrew Morton --- fs/eventpoll.c | 42 +++++++++++++++++++++--------------------- 1 file changed, 21 insertions(+), 21 deletions(-) --- a/fs/eventpoll.c~epoll-replace-gotos-with-a-proper-loop +++ a/fs/eventpoll.c @@ -1743,7 +1743,7 @@ static inline struct timespec64 ep_set_m static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events, int maxevents, long timeout) { - int res, eavail, timed_out = 0; + int res, eavail = 0, timed_out = 0; u64 slack = 0; wait_queue_entry_t wait; ktime_t expires, *to = NULL; @@ -1769,18 +1769,30 @@ static int ep_poll(struct eventpoll *ep, write_lock_irq(&ep->lock); eavail = ep_events_available(ep); write_unlock_irq(&ep->lock); - - goto send_events; } -fetch_events: - do { + while (1) { + if (eavail) { + /* + * Try to transfer events to user space. In case we get + * 0 events and there's still timeout left over, we go + * trying again in search of more luck. + */ + res = ep_send_events(ep, events, maxevents); + if (res) + return res; + } + + if (timed_out) + return 0; + eavail = ep_events_available(ep); - if (!eavail) - eavail = ep_busy_loop(ep, timed_out); + if (eavail) + continue; + eavail = ep_busy_loop(ep, timed_out); if (eavail) - goto send_events; + continue; if (signal_pending(current)) return -EINTR; @@ -1845,19 +1857,7 @@ fetch_events: __remove_wait_queue(&ep->wq, &wait); write_unlock_irq(&ep->lock); } - } while (0); - -send_events: - /* - * Try to transfer events to user space. In case we get 0 events and - * there's still timeout left over, we go trying again in search of - * more luck. - */ - if (eavail && - !(res = ep_send_events(ep, events, maxevents)) && !timed_out) - goto fetch_events; - - return res; + } } /** _