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[23.128.96.38]) by mx.google.com with ESMTPS id i2-20020a170902c94200b001b8904eadb8si2152524pla.460.2023.11.08.02.57.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 08 Nov 2023 02:57:50 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.38 as permitted sender) client-ip=23.128.96.38; Authentication-Results: mx.google.com; dkim=pass header.i=@shopee.com header.s=shopee.com header.b=kl4br25R; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.38 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=shopee.com Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by fry.vger.email (Postfix) with ESMTP id 2183C81C50B7; Wed, 8 Nov 2023 02:57:47 -0800 (PST) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.11 at fry.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344385AbjKHK5c (ORCPT + 32 others); Wed, 8 Nov 2023 05:57:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54500 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344528AbjKHK5W (ORCPT ); Wed, 8 Nov 2023 05:57:22 -0500 Received: from mail-pl1-x62d.google.com (mail-pl1-x62d.google.com [IPv6:2607:f8b0:4864:20::62d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A2B8B19BA for ; Wed, 8 Nov 2023 02:57:20 -0800 (PST) Received: by mail-pl1-x62d.google.com with SMTP id d9443c01a7336-1cc316ccc38so54938985ad.1 for ; Wed, 08 Nov 2023 02:57:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=shopee.com; s=shopee.com; t=1699441040; x=1700045840; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=Xn2IA5P26vaovRSBo2ciBaT5wWZFGHvMT0WOwKqY8ag=; b=kl4br25R6LOG23ScjAqRq3bCG0JzK68uySVKr7cuJcf+vuTTU+CKPZOuPjBHeYU2O7 mUWI8C0EXBP0cQF5bfndLpdkURamngqmvfpVmbRZzSetRlVxk5PFYSobjLorDzA+SXHG cQeW3vwP9J3I5uXXoE91NJciUezQJfq9PHQqUSYFcAA5WFwdzcNPkeTFsjEdveiwnpRq 8oQN/F1myWSTdOQ2uoW38MqlT+TlMOKEmH5KfoShPGFhT73x6XEWEuerm6yOex6NAHbt UjiDxBTAiXEX8YuPRv5lDcimQW9LY2u8grbxg+RayT9I204b5EeZ/ff9gME87VQItPpW vlzQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1699441040; x=1700045840; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=Xn2IA5P26vaovRSBo2ciBaT5wWZFGHvMT0WOwKqY8ag=; b=YmsTg0TsoQqR4A+UUq+NoxSNLBKdVSTzEWWH42Fp0ULpNUBaoMUqGNzZd2mnI8HXTF dUYtqgjX8+lsj6qocB58JWagvw4Pcym8+qnZ0ey94db1TChQQTXEe/hODK5nZpPCxZpo RD5IhJQPz0KZdSDbAuideVzU44Ci/M1F7QhHBshz9jCh8hSAfrN/EUxoetnA+Ofvue2f o7XJpJOWQ1NmOndNScOdo3mQH3nRTBpQzGz8RmXH1apNPv6Wx9IyZlPe7NfUJmQE1s/P yDU6YCiCcHSz5/IGL2TydoYVhL5n6Vij7QvsejB9+djEaHBGyzDkL3VHXi4HbInxSUgU +JMg== X-Gm-Message-State: AOJu0YwqaRe+J/Ws+WLagVC6Fi6KdzvjMV5rzXDvg7/ysj2EJpetIbRr ozKFMxg5eUICn/HwdHpbDXiqRw== X-Received: by 2002:a17:903:11ce:b0:1cc:b09a:b811 with SMTP id q14-20020a17090311ce00b001ccb09ab811mr1864075plh.14.1699441040125; Wed, 08 Nov 2023 02:57:20 -0800 (PST) Received: from ubuntu-hf2.default.svc.cluster.local ([101.127.248.173]) by smtp.gmail.com with ESMTPSA id 12-20020a170902c14c00b001cc79f3c60csm1468546plj.31.2023.11.08.02.57.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 08 Nov 2023 02:57:19 -0800 (PST) From: Haifeng Xu To: longman@redhat.com Cc: peterz@infradead.org, mingo@redhat.com, will@kernel.org, boqun.feng@gmail.com, linux-kernel@vger.kernel.org, Haifeng Xu Subject: [PATCH] locking/rwsem: Remove unnessary check in rwsem_down_read_slowpath() Date: Wed, 8 Nov 2023 10:56:39 +0000 Message-Id: <20231108105639.70088-1-haifeng.xu@shopee.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (fry.vger.email [0.0.0.0]); Wed, 08 Nov 2023 02:57:47 -0800 (PST) X-Spam-Status: No, score=-0.9 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on fry.vger.email X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1781993119554856221 X-GMAIL-MSGID: 1781993119554856221 When the owner of rw_semaphore is reader, the count can't be RWSEM_WRITER_LOCKED, so there is no need to check it. Signed-off-by: Haifeng Xu --- kernel/locking/rwsem.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index 2340b6d90ec6..7a4d8a9ebd9c 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -1005,8 +1005,7 @@ rwsem_down_read_slowpath(struct rw_semaphore *sem, long count, unsigned int stat * waiter, don't attempt optimistic lock stealing if the lock is * currently owned by readers. */ - if ((atomic_long_read(&sem->owner) & RWSEM_READER_OWNED) && - (rcnt > 1) && !(count & RWSEM_WRITER_LOCKED)) + if ((atomic_long_read(&sem->owner) & RWSEM_READER_OWNED) && (rcnt > 1)) goto queue; /*