From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C3D534414; Sat, 14 Sep 2024 16:51:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726332672; cv=none; b=mzB/+afRNe8DEjU7ZUxXZ9tar8Swi4JMWJPHHhC92jptgB0ItgAAI1tA3ICuBQxswtKY7JfIlfOtVpp4DITQkgFPJ6vjOKqKhnPJOPwjc+YaErsC4wqEfdMMEwWgqT8w3gs2t2GMwJE+3wk8Ez9DXdX1gTbzznYODcKmPtoDWb8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726332672; c=relaxed/simple; bh=Z71g/E3I7Jij2MRKNDH6gqkcbdpZ8+UYJCRd77hL9Vk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=K83/QUOWTdh+cVATBshTQyD/Je1PuqtTXcHqrK4VsH7/Ia1OCCr/d7mqpeUsv62UoMIanZ91zm6PayInhAeZ3KkY7bcNG0P20CygIMY+LK36TB5jyOCqtDejFv7okmC35RFTHQ3UZIDGbwTg5K1uP3oZ/LSPwm9LIic1n6dqsSE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mpitQDL1; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mpitQDL1" 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> Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240914073011.GA30261@lst.de> 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?