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[23.128.96.31]) by mx.google.com with ESMTPS id y5-20020a63ce05000000b00573fc71f6d9si18069086pgf.64.2023.09.28.01.23.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 28 Sep 2023 01:23:32 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.31 as permitted sender) client-ip=23.128.96.31; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.31 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 morse.vger.email (Postfix) with ESMTP id 5457481C99BC; Thu, 28 Sep 2023 01:19:26 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at morse.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231276AbjI1ISn (ORCPT + 20 others); Thu, 28 Sep 2023 04:18:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56856 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231200AbjI1ISi (ORCPT ); Thu, 28 Sep 2023 04:18:38 -0400 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 37538B4; Thu, 28 Sep 2023 01:18:36 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.169]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4Rx5w66rfSz4f3m7f; Thu, 28 Sep 2023 16:18:30 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.124.27]) by APP3 (Coremail) with SMTP id _Ch0CgAngVDXNhVlhwUABg--.50964S3; 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 1/2] pipe: remove pipe_full check with wrong head in pipe_write Date: Fri, 29 Sep 2023 00:17:51 +0800 Message-Id: <20230928161752.142268-2-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--.50964S3 X-Coremail-Antispam: 1UD129KBjvdXoWruF13Cw1xAr45GF1xurWDXFb_yoWkKFgEka 97CFn3ur43Jr48Jw17CFnakryxW34Uur1UZrW5Ar9xJF1kWr98u3s5W34DC34UZ3Z8tF9x C392van2vr1fWjkaLaAFLSUrUUUUUb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUIcSsGvfJTRUUUbfkYFVCjjxCrM7AC8VAFwI0_Gr0_Xr1l1xkIjI8I6I8E6xAIw20E Y4v20xvaj40_Wr0E3s1l1IIY67AEw4v_Jr0_Jr4l87I20VAvwVAaII0Ic2I_JFv_Gryl82 xGYIkIc2x26280x7IE14v26r18M28IrcIa0xkI8VCY1x0267AKxVWUXVWUCwA2ocxC64kI II0Yj41l84x0c7CEw4AK67xGY2AK021l84ACjcxK6xIIjxv20xvE14v26w1j6s0DM28EF7 xvwVC0I7IYx2IY6xkF7I0E14v26r4UJVWxJr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2 z4x0Y4vEx4A2jsIEc7CjxVAFwI0_GcCE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4 xG64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_JrI_JrylYx0Ex4A2jsIE14v2 6r1j6r4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwCF04k20xvY0x0EwI xGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480 Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_JF0_Jw1lIxkGc2Ij64vIr41lIxAIcVC0I7 IYx2IY67AKxVW8JVW5JwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Cr0_Gr1UMIIF0xvE42xK 8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVW8JVWxJwCI42IY6I8E87Iv6xkF7I 0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjxUxsqWUUUUU X-CM-SenderInfo: 5vklyvpphqwq5kxd4v5lfo033gof0z/ X-CFilter-Loop: Reflected X-Spam-Status: No, score=-0.8 required=5.0 tests=DATE_IN_FUTURE_06_12, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on morse.vger.email 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 (morse.vger.email [0.0.0.0]); Thu, 28 Sep 2023 01:19:27 -0700 (PDT) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1778268936954561727 X-GMAIL-MSGID: 1778268936954561727 In pipe_write we have: head = pipe->head; if (!pipe_full(head, pipe->tail, pipe->max_usage)) pipe->head = head + 1; /* write data to buffer at head */ /* supposed to check if pipe is full after write */ if (!pipe_full(head, pipe->tail, pipe->max_usage)) continue The second pipe_full expects head after write but head before write is used. Luckily, we will call pipe_full with correct reloaded pipe->head in new loop cycle and stop writing correctly. Remove wrong pipe_full check and simply continue to first pipe_full check after write done to avoid unnecessary check. Fixes: a194dfe6e6f6 ("pipe: Rearrange sequence in pipe_write() to preallocate slot") Signed-off-by: Kemeng Shi --- fs/pipe.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/fs/pipe.c b/fs/pipe.c index 2d88f73f585a..b19875720ff1 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -542,10 +542,9 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from) if (!iov_iter_count(from)) break; - } - if (!pipe_full(head, pipe->tail, pipe->max_usage)) continue; + } /* Wait for buffer space to become available. */ if ((filp->f_flags & O_NONBLOCK) ||