From patchwork Mon Jul 12 06:08:38 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 476349 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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, 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 76B9EC07E9C for ; Mon, 12 Jul 2021 06:20:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5DBA8610A6 for ; Mon, 12 Jul 2021 06:20:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234690AbhGLGXf (ORCPT ); Mon, 12 Jul 2021 02:23:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:37428 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234590AbhGLGWh (ORCPT ); Mon, 12 Jul 2021 02:22:37 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id D6F4C6115C; Mon, 12 Jul 2021 06:19:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626070771; bh=GoeJ6QtsonK8GSez6muOYu6J939okEtS/8qcrZYi8OQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tblD9MRs26cF2UNPqRy1QY8ap0z0BbeK8gmds4kpxhgQrH6VEfFRUerq2pJt5iS18 RS9tuSDPHKmkKuHAz0eIoh2o4eQTRCfTFNoz0unQoWa9I+XadOn6XKB58a2d2IrXMG XLUzuLFxOWwf6eW1ODgiyKE6gWnCXtAGoSydgGzM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Christoph Hellwig , Wang Shanker , Ming Lei , Jens Axboe , Sasha Levin Subject: [PATCH 5.4 134/348] block: fix discard request merge Date: Mon, 12 Jul 2021 08:08:38 +0200 Message-Id: <20210712060719.040905592@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210712060659.886176320@linuxfoundation.org> References: <20210712060659.886176320@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Ming Lei [ Upstream commit 2705dfb2094777e405e065105e307074af8965c1 ] ll_new_hw_segment() is reached only in case of single range discard merge, and we don't have max discard segment size limit actually, so it is wrong to run the following check: if (req->nr_phys_segments + nr_phys_segs > blk_rq_get_max_segments(req)) it may be always false since req->nr_phys_segments is initialized as one, and bio's segment count is still 1, blk_rq_get_max_segments(reg) is 1 too. Fix the issue by not doing the check and bypassing the calculation of discard request's nr_phys_segments. Based on analysis from Wang Shanker. Cc: Christoph Hellwig Reported-by: Wang Shanker Signed-off-by: Ming Lei Link: https://lore.kernel.org/r/20210628023312.1903255-1-ming.lei@redhat.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- block/blk-merge.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/block/blk-merge.c b/block/blk-merge.c index 03959bfe961c..4b022f0c49d2 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -571,10 +571,14 @@ static inline unsigned int blk_rq_get_max_segments(struct request *rq) static inline int ll_new_hw_segment(struct request *req, struct bio *bio, unsigned int nr_phys_segs) { - if (req->nr_phys_segments + nr_phys_segs > blk_rq_get_max_segments(req)) + if (blk_integrity_merge_bio(req->q, req, bio) == false) goto no_merge; - if (blk_integrity_merge_bio(req->q, req, bio) == false) + /* discard request merge won't add new segment */ + if (req_op(req) == REQ_OP_DISCARD) + return 1; + + if (req->nr_phys_segments + nr_phys_segs > blk_rq_get_max_segments(req)) goto no_merge; /*