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 DAA95C021A8 for ; Sat, 14 Sep 2024 16:51:21 +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=jEb/ijWd3qoEkpmMA3rsWD2rYDkEJ8WooW+jRGh20uk=; b=KprWQe5GrgPbbpyM3d0YVZ8zvk blNv2zQgriUFt0woi9N/DwcGUkWksj0SA2OYucolavmc/5A55jC6EgW6EMdX1aD/543VLKCpRGtKD 4tcGujZqZNRVJoJ5OMrPAcwKqiTK8HBWFIndotuUXkUySAPcleZamPjalBvTL64utum2/kZ0n0mBt eCU43Q3hg7ZyHhnr5W9TKZVeNdxK02zBOd9T2MxhIYrCj6CQic+5+ST6LjMviLnXoq4FLxLQFqZv3 JGLsJLsuv8xGFDMcu2+Djfp3iRsk/VpwxtRx/ZSVzlnEzj0MNOyr57ExV4FQ/vGRefFkjcs8/4rDF rauyfMJQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1spVzR-00000000yCl-2Az7; Sat, 14 Sep 2024 16:51:17 +0000 Received: from nyc.source.kernel.org ([2604:1380:45d1:ec00::3]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1spVzO-00000000yCL-3TIV for linux-nvme@lists.infradead.org; Sat, 14 Sep 2024 16:51:16 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id 4E2C3A40148; Sat, 14 Sep 2024 16:51:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D6BE7C4CEC0; Sat, 14 Sep 2024 16:51:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1726332672; bh=Z71g/E3I7Jij2MRKNDH6gqkcbdpZ8+UYJCRd77hL9Vk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=mpitQDL1e/aY6KvLGIo3aTY3pIfqMYtDBf/BdOBMaHPqPxyIaTTlz+oxsjp624wPj 1ycwpdjSWg2IDC2kr4/Ba4VYLORvBVAAhfft4TRUYE2HNAmRWVzeRobn6+CeApttgM C8lncDQfs1jBvv5L4x00VQiRfY45Z6QUUPoIDCDuZomSG5epIQGke+lGVnuD4gVzN8 xLfC9FVU9/GqVut7P/3reZrKSOrPfp/rWC72L92MWK9HmdlhEeqEhuK9D3gwvfbUsM GgbJekkvTd1hhO1RG9VxorZ4QlhI8d9c5s/RKPSclGKbqyCm+GqOaH2VUi/mZW8QnI rmsjCpeTmVKKw== Date: Sat, 14 Sep 2024 10:51:10 -0600 From: Keith Busch To: Christoph Hellwig Cc: Keith Busch , axboe@kernel.dk, martin.petersen@oracle.com, linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org, sagi@grimberg.me Subject: Re: [PATCHv5 4/9] blk-integrity: consider entire bio list for merging Message-ID: References: <20240913182854.2445457-1-kbusch@meta.com> <20240913182854.2445457-5-kbusch@meta.com> <20240914073011.GA30261@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240914073011.GA30261@lst.de> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240914_095114_955695_8FAF674B X-CRM114-Status: GOOD ( 15.81 ) 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 Sat, Sep 14, 2024 at 09:30:12AM +0200, Christoph Hellwig wrote: > 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. Could you explain "wrong"? If we assume there is never bio list here, then the current code is performing a useless no-op, and this patch removes it. That's a good thing, no?