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=-8.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 DCE40C43218 for ; Thu, 25 Apr 2019 13:32:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9AF1B20652 for ; Thu, 25 Apr 2019 13:32:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=zoho.com header.i=yehs2007@zoho.com header.b="BtkK5IuR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729188AbfDYNcg (ORCPT ); Thu, 25 Apr 2019 09:32:36 -0400 Received: from sender4-pp-o95.zoho.com ([136.143.188.95]:25544 "EHLO sender4-pp-o95.zoho.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725955AbfDYNcg (ORCPT ); Thu, 25 Apr 2019 09:32:36 -0400 ARC-Seal: i=1; a=rsa-sha256; t=1556199127; cv=none; d=zoho.com; s=zohoarc; b=a6S501wnq0WxXo5JP1mk9blEP9wWdxvfLkrAgJ4PBLcYoDgejfkStul6vH8IEyXTAYtjRyMJTYev6i3MULyHzMOoGzM6ap7e4jyOBls9FG68ShRKxyGhMETU7ucTipHhNI4OzfyJyKRsMMjWKi1VsnMEJe3JwWvw0zVous7Xdhw= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zoho.com; s=zohoarc; t=1556199127; h=Cc:Date:From:In-Reply-To:Message-ID:References:Subject:To:ARC-Authentication-Results; bh=FyEDAx0dBD84M+NBbPh51XO5Ixmi4K5yOWlO3BekT1Y=; b=Cr9MfuwQxdAUqwurmo/vWNXgs47vuYDp8xTbwj4rMqiRkMp64lgIvMOGZCrBcw6HulFpEezubEDD7R+vHVmdv80XjH66yiPgZLKdLRnLoxcXYZjWuru+vNYSubyZOdvhZgxuEC9Hn0DZ90LHHrQGAYA+wjFbObRs+QrNKyHZDPs= ARC-Authentication-Results: i=1; mx.zoho.com; dkim=pass header.i=zoho.com; spf=pass smtp.mailfrom=yehs2007@zoho.com; dmarc=pass header.from= header.from= DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=zapps768; d=zoho.com; h=from:to:cc:subject:date:message-id:in-reply-to:references; b=oOlHQabxwPZPe9eqdhl78i9rU5RXbSUKXrUvLgT9IpL2SQ8gT0Uv3YpRlYAeMOUrdltC8EzjZ9cs dym2llJBlXdT0YcaRklsbtWT7Qb95guYkMYFR9vssHr46nm7CDLl DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1556199127; s=default; d=zoho.com; i=yehs2007@zoho.com; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References; l=1206; bh=FyEDAx0dBD84M+NBbPh51XO5Ixmi4K5yOWlO3BekT1Y=; b=BtkK5IuR3pAUKiy/7blmxkaebOjFjTgHK+ADvGv4dpgPlT2f0pf4o8p3BZBnCXN3 qxXKmY+JkJIqB4cC9VgrndqyNld/ma8aIpVsB4Vwkir2nGi/DFpEd6TKm7oD/G39bSd eNDAeSDfl/HCRg9d2QT8boqWDJHkoZunFB3YS5Wc= Received: from YEHS1XR3054QMS.lenovo.com (123.120.108.196 [123.120.108.196]) by mx.zohomail.com with SMTPS id 155619912704786.25566430035269; Thu, 25 Apr 2019 06:32:07 -0700 (PDT) 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 v2 2/4] dm writecache: add unlikely for returned value of rb_next/prev Date: Thu, 25 Apr 2019 21:31:18 +0800 Message-Id: <20190425133120.13088-3-yehs2007@zoho.com> X-Mailer: git-send-email 2.17.0.windows.1 In-Reply-To: <20190425133120.13088-1-yehs2007@zoho.com> References: <20190425133120.13088-1-yehs2007@zoho.com> X-ZohoMailClient: External 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 a high probablity that the pointer of structure rb_node won't equal NULL. Add unlikely for the pointer node NULL. Signed-off-by: Huaisheng Ye Acked-by: Mikulas Patocka Signed-off-by: Mike Snitzer --- 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