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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D10F0C43334 for ; Thu, 14 Jul 2022 17:38:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239470AbiGNRic (ORCPT ); Thu, 14 Jul 2022 13:38:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33298 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232679AbiGNRib (ORCPT ); Thu, 14 Jul 2022 13:38:31 -0400 Received: from mail-ed1-x534.google.com (mail-ed1-x534.google.com [IPv6:2a00:1450:4864:20::534]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F1B59606B6; Thu, 14 Jul 2022 10:38:30 -0700 (PDT) Received: by mail-ed1-x534.google.com with SMTP id x91so3366433ede.1; Thu, 14 Jul 2022 10:38:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=Yu2+SIwToyiijVbo49UhP1kKR2aa55foE/D2/YT55Yg=; b=IWw5CaMfCXVmaVCS03FgCetqbph2FBq2DUnPT/8+/8GQMunsfmxv0pYinebZmpiuq3 Y+ZXXUC12JAPvmVqatMBk5t/MzDjcc7+XhpU2CRuLNYH96ZQz86xc/tmUyb+cZ6A5JoK IttW1wUcqf3GZ436e7C3CZLqtT9JV84KIUArFqMXyUFqR7tHznpw6QNFf/qvF2l98Yat QlulbkF6P9Ltj3XDWaZVAaf8gAKS5aD1NC7gQh6mcBp6MM79Mt0VC9GrVwYvz8cu6dal o10N2lLvoGNqST0P9Pg6eB6vketB+wvZtFehLb1VWg5vPSH6FWJGNA1VuQFNeMOWscgG DXeg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=Yu2+SIwToyiijVbo49UhP1kKR2aa55foE/D2/YT55Yg=; b=f4bJ7gFQDJmm0zXMeUJfYzaXkWueEEMU48liDWxfU/rVORO+g9DYWaPBfSIFG/Ofzm GRrZWo2HG37FVRTyJTliXC8hDakwC92waKC9dhFPCeLOJm/IgB3KDZand6Wnq2k5MAz2 oeLL9vxH3t3OjNl/q8Q6c3XTeOu2qWDB7MECxNIo/YfJZL8qChLRVfxeDuD/HkFdH2R1 YWVBqK4sHiSutSioLvwwJ+FMzmzwI+s/g85mEY3tTYiILzz0Nf7Z2Mvt83jmVyXvNti0 qn6R1Y8L/ta8KFIi/PKGXLkmoDH3Ob61HAv8jQUStdCSxe15yHQ4Fmg5pVvioLdPkJY1 g0Xg== X-Gm-Message-State: AJIora+r1hgBNDuZvRMJNLeA1K5qync+0eD7/zPcCZFaRUNn0ck0tzQs YRuA8hZBzuINfyxDn1P454H0VTQm6WA= X-Google-Smtp-Source: AGRyM1sp11JRsdFgMZcGctJa6r0ts/rppEWWYSPQdRobSA6f2F4IXltHCnp1Q3lsilwqlAoKnBW2aw== X-Received: by 2002:aa7:dd06:0:b0:43b:247e:3d6c with SMTP id i6-20020aa7dd06000000b0043b247e3d6cmr5120458edv.407.1657820309353; Thu, 14 Jul 2022 10:38:29 -0700 (PDT) Received: from localhost.localdomain ([46.248.82.114]) by smtp.gmail.com with ESMTPSA id j17-20020a17090623f100b0072a55ec6f3bsm942235ejg.165.2022.07.14.10.38.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Jul 2022 10:38:28 -0700 (PDT) From: Uros Bizjak To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Uros Bizjak , Alexander Viro Subject: [PATCH] posix_acl: Use try_cmpxchg in get_acl Date: Thu, 14 Jul 2022 19:38:19 +0200 Message-Id: <20220714173819.13312-1-ubizjak@gmail.com> X-Mailer: git-send-email 2.35.3 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Use try_cmpxchg instead of cmpxchg (*ptr, old, new) == old in get_acl. x86 CMPXCHG instruction returns success in ZF flag, so this change saves a compare after cmpxchg (and related move instruction in front of cmpxchg). No functional change intended. Signed-off-by: Uros Bizjak Cc: Alexander Viro --- fs/posix_acl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/posix_acl.c b/fs/posix_acl.c index 962d32468eb4..49a13fd4d3cb 100644 --- a/fs/posix_acl.c +++ b/fs/posix_acl.c @@ -164,7 +164,7 @@ struct posix_acl *get_acl(struct inode *inode, int type) * Cache the result, but only if our sentinel is still in place. */ posix_acl_dup(acl); - if (unlikely(cmpxchg(p, sentinel, acl) != sentinel)) + if (unlikely(!try_cmpxchg(p, &sentinel, acl))) posix_acl_release(acl); return acl; } -- 2.35.3