From patchwork Wed Dec 12 11:03:55 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roman Penyaev X-Patchwork-Id: 10726101 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1272E112E for ; Wed, 12 Dec 2018 11:05:04 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 02D9E2A5A1 for ; Wed, 12 Dec 2018 11:05:04 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E64102AEF3; Wed, 12 Dec 2018 11:05:03 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 614052A5A1 for ; Wed, 12 Dec 2018 11:05:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727204AbeLLLEd (ORCPT ); Wed, 12 Dec 2018 06:04:33 -0500 Received: from mx2.suse.de ([195.135.220.15]:46018 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726970AbeLLLEd (ORCPT ); Wed, 12 Dec 2018 06:04:33 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 63E23AE8A; Wed, 12 Dec 2018 11:04:31 +0000 (UTC) From: Roman Penyaev Cc: Roman Penyaev , Davidlohr Bueso , Jason Baron , Al Viro , Andrew Morton , Linus Torvalds , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/3] epoll: make sure all elements in ready list are in FIFO order Date: Wed, 12 Dec 2018 12:03:55 +0100 Message-Id: <20181212110357.25656-2-rpenyaev@suse.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181212110357.25656-1-rpenyaev@suse.de> References: <20181212110357.25656-1-rpenyaev@suse.de> MIME-Version: 1.0 To: unlisted-recipients:; (no To-header on input) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP All coming events are stored in FIFO order and this is also should be applicable to ->ovflist, which originally is stack, i.e. LIFO. Thus to keep correct FIFO order ->ovflist should reversed by adding elements to the head of the read list but not to the tail. Signed-off-by: Roman Penyaev Cc: Davidlohr Bueso Cc: Jason Baron Cc: Al Viro Cc: Andrew Morton Cc: Linus Torvalds Cc: linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Reviewed-by: Davidlohr Bueso --- fs/eventpoll.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 2329f96469e2..3627c2e07149 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -722,7 +722,11 @@ static __poll_t ep_scan_ready_list(struct eventpoll *ep, * contain them, and the list_splice() below takes care of them. */ if (!ep_is_linked(epi)) { - list_add_tail(&epi->rdllink, &ep->rdllist); + /* + * ->ovflist is LIFO, so we have to reverse it in order + * to keep in FIFO. + */ + list_add(&epi->rdllink, &ep->rdllist); ep_pm_stay_awake(epi); } }