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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id EEEB2C02180 for ; Sat, 14 Sep 2024 07:30:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=1LkSRQY51hkVSL6WRjKaPsecsrDipcRvjxZ1p5eH0bU=; b=wDj6pSSoqOG3ioJCZ6dqOqZPxb ZZOwbgMr+o4xKKYH0FXe8nz1k39QdNA3vt7Yrmc8MJkfIqssXnFXiir/A64uKf3NeEvGLQtmHMs9P N62izV6Gsbu5cU+noesDL9TOqHcbJF0lcRekiJ28TvXtg0+qI8ou/WgW3YELurtQS71xy1YCZIAbX 3spYNogBySTPXSCHXHEQFCQ6bxQVeKrIc08m8Dg0WTI20SVe38G0yPlRWmvZPfhUP0Lcyx6gzzKSR g3SWeZhfKuFuS5wIdGRTTUuVfiZtSzFRiwWIl/5fKDtM87PXQdpg6ACPPQn8imtS8/TefN7TL8QDx pxBeQtQA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1spNEi-00000000IB1-29UM; Sat, 14 Sep 2024 07:30:28 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1spNEb-00000000IAF-2hTu for linux-nvme@lists.infradead.org; Sat, 14 Sep 2024 07:30:23 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 63265227AAA; Sat, 14 Sep 2024 09:30:12 +0200 (CEST) Date: Sat, 14 Sep 2024 09:30:12 +0200 From: Christoph Hellwig To: Keith Busch Cc: axboe@kernel.dk, hch@lst.de, martin.petersen@oracle.com, linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org, sagi@grimberg.me, Keith Busch Subject: Re: [PATCHv5 4/9] blk-integrity: consider entire bio list for merging Message-ID: <20240914073011.GA30261@lst.de> References: <20240913182854.2445457-1-kbusch@meta.com> <20240913182854.2445457-5-kbusch@meta.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240913182854.2445457-5-kbusch@meta.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240914_003021_851163_45C69258 X-CRM114-Status: GOOD ( 13.25 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Fri, Sep 13, 2024 at 11:28:49AM -0700, Keith Busch wrote: > From: Keith Busch > > If a bio is merged to a request, the entire bio list is merged, so don't > temporarily detach it from its list when counting segments. In most > cases, bi_next will already be NULL, so detaching is usually a no-op. > But if the bio does have a list, the current code is miscounting the > segments for the resulting merge. As I explained in detail last round this is still wrong. There is no bio list here ever.