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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 E1432C10F0E for ; Fri, 12 Apr 2019 15:28:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AF010218A3 for ; Fri, 12 Apr 2019 15:28:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727204AbfDLP2j (ORCPT ); Fri, 12 Apr 2019 11:28:39 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34446 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727170AbfDLP2j (ORCPT ); Fri, 12 Apr 2019 11:28:39 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E5026308CFBF; Fri, 12 Apr 2019 15:28:38 +0000 (UTC) Received: from dhcp16-201-219.khw1.lab.eng.bos.redhat.com (dhcp16-201-219.khw1.lab.eng.bos.redhat.com [10.16.201.219]) by smtp.corp.redhat.com (Postfix) with ESMTP id B252560BEC; Fri, 12 Apr 2019 15:28:31 +0000 (UTC) From: Huaisheng Ye To: mpatocka@redhat.com, snitzer@redhat.com, agk@redhat.com Cc: prarit@redhat.com, chengnt@lenovo.com, dm-devel@redhat.com, linux-kernel@vger.kernel.org, Huaisheng Ye Subject: [PATCH] dm-writecache: add unlikely for returned value of rb_next/prev Date: Fri, 12 Apr 2019 11:28:14 -0400 Message-Id: <20190412152814.27158-1-huye@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.44]); Fri, 12 Apr 2019 15:28:38 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Huaisheng Ye In functions writecache_discard and writecache_find_entry, there is high probablity that the pointer of structure rb_node doesn't equal to NULL. Add unlikly for the pointer node. Signed-off-by: Huaisheng Ye --- drivers/md/dm-writecache.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c index 5b4d1c1..cfbbfbc 100644 --- a/drivers/md/dm-writecache.c +++ b/drivers/md/dm-writecache.c @@ -571,7 +571,7 @@ static struct wc_entry *writecache_find_entry(struct dm_writecache *wc, node = rb_prev(&e->rb_node); else node = rb_next(&e->rb_node); - if (!node) + if (unlikely(!node)) return e; e2 = container_of(node, struct wc_entry, rb_node); if (read_original_sector(wc, e2) != block) @@ -804,7 +804,7 @@ static void writecache_discard(struct dm_writecache *wc, sector_t start, sector_ writecache_free_entry(wc, e); } - if (!node) + if (unlikely(!node)) break; e = container_of(node, struct wc_entry, rb_node); -- 1.8.3.1