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[23.128.96.37]) by mx.google.com with ESMTPS id c3-20020a6566c3000000b0056534300dc2si17634521pgw.247.2023.09.28.01.53.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 28 Sep 2023 01:53:01 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.37 as permitted sender) client-ip=23.128.96.37; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.37 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by snail.vger.email (Postfix) with ESMTP id 7D58080A73FB; Thu, 28 Sep 2023 01:18:44 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at snail.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230338AbjI1ISi (ORCPT + 20 others); Thu, 28 Sep 2023 04:18:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56840 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229539AbjI1ISh (ORCPT ); Thu, 28 Sep 2023 04:18:37 -0400 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E90B8B3; Thu, 28 Sep 2023 01:18:35 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.169]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4Rx5w71sVyz4f3mHZ; Thu, 28 Sep 2023 16:18:31 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.124.27]) by APP3 (Coremail) with SMTP id _Ch0CgAngVDXNhVlhwUABg--.50964S4; Thu, 28 Sep 2023 16:18:33 +0800 (CST) From: Kemeng Shi To: viro@zeniv.linux.org.uk, brauner@kernel.org, dhowells@redhat.com Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/2] pipe: avoid repeat check of pipe->readers with pipe lock held Date: Fri, 29 Sep 2023 00:17:52 +0800 Message-Id: <20230928161752.142268-3-shikemeng@huaweicloud.com> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20230928161752.142268-1-shikemeng@huaweicloud.com> References: <20230928161752.142268-1-shikemeng@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: _Ch0CgAngVDXNhVlhwUABg--.50964S4 X-Coremail-Antispam: 1UD129KBjvdXoW7GFyDJF1xZrWxCw18WFyxuFg_yoWDtwbEk3 92yF1rWr1fJrWxXa17CF1ayr4UuryDAr17Zr1Yyr9rGF18WryDu3Z5ZFy8AryUXan8GF9x Ca9Fyr9rJr1xCjkaLaAFLSUrUUUUUb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUIcSsGvfJTRUUUbfAYFVCjjxCrM7AC8VAFwI0_Xr0_Wr1l1xkIjI8I6I8E6xAIw20E Y4v20xvaj40_Wr0E3s1l1IIY67AEw4v_Jr0_Jr4l87I20VAvwVAaII0Ic2I_JFv_Gryl82 xGYIkIc2x26280x7IE14v26r15M28IrcIa0xkI8VCY1x0267AKxVWUCVW8JwA2ocxC64kI II0Yj41l84x0c7CEw4AK67xGY2AK021l84ACjcxK6xIIjxv20xvE14v26w1j6s0DM28EF7 xvwVC0I7IYx2IY6xkF7I0E14v26r4UJVWxJr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2 z4x0Y4vEx4A2jsIEc7CjxVAFwI0_GcCE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4 xG64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_JrI_JrylYx0Ex4A2jsIE14v2 6r1j6r4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwCF04k20xvY0x0EwI xGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480 Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_JF0_Jw1lIxkGc2Ij64vIr41lIxAIcVC0I7 IYx2IY67AKxVW8JVW5JwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Cr0_Gr1UMIIF0xvE42xK 8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVW8JVWxJwCI42IY6I8E87Iv6xkF7I 0E14v26r4UJVWxJrUvcSsGvfC2KfnxnUUI43ZEXa7IU0TrW7UUUUU== X-CM-SenderInfo: 5vklyvpphqwq5kxd4v5lfo033gof0z/ X-CFilter-Loop: Reflected X-Spam-Status: No, score=0.0 required=5.0 tests=BAYES_00,DATE_IN_FUTURE_06_12, RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net 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 (snail.vger.email [0.0.0.0]); Thu, 28 Sep 2023 01:18:44 -0700 (PDT) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1778270791362076018 X-GMAIL-MSGID: 1778270791362076018 Change to pipe->readers is protected by pipe_lock. Only recheck pipe->reader after relock to avoid repeat check of pipe->readers with pipe lock held. Signed-off-by: Kemeng Shi --- fs/pipe.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/fs/pipe.c b/fs/pipe.c index b19875720ff1..e9c63f66d1c7 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -479,13 +479,6 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from) } for (;;) { - if (!pipe->readers) { - send_sig(SIGPIPE, current, 0); - if (!ret) - ret = -EPIPE; - break; - } - head = pipe->head; if (!pipe_full(head, pipe->tail, pipe->max_usage)) { unsigned int mask = pipe->ring_size - 1; @@ -573,6 +566,12 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from) __pipe_lock(pipe); was_empty = pipe_empty(pipe->head, pipe->tail); wake_next_writer = true; + if (!pipe->readers) { + send_sig(SIGPIPE, current, 0); + if (!ret) + ret = -EPIPE; + break; + } } out: if (pipe_full(pipe->head, pipe->tail, pipe->max_usage))