Return-Path: Received: from verein.lst.de ([213.95.11.211]:46161 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727733AbeKUCqr (ORCPT ); Tue, 20 Nov 2018 21:46:47 -0500 Date: Tue, 20 Nov 2018 17:16:51 +0100 From: Christoph Hellwig To: Sagi Grimberg Cc: Christoph Hellwig , Ming Lei , Jens Axboe , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Dave Chinner , Kent Overstreet , Mike Snitzer , dm-devel@redhat.com, Alexander Viro , linux-fsdevel@vger.kernel.org, Shaohua Li , linux-raid@vger.kernel.org, linux-erofs@lists.ozlabs.org, David Sterba , linux-btrfs@vger.kernel.org, "Darrick J . Wong" , linux-xfs@vger.kernel.org, Gao Xiang , Theodore Ts'o , linux-ext4@vger.kernel.org, Coly Li , linux-bcache@vger.kernel.org, Boaz Harrosh , Bob Peterson , cluster-devel@redhat.com Subject: Re: [PATCH V10 09/19] block: introduce bio_bvecs() Message-ID: <20181120161651.GB2629@lst.de> References: <20181115085306.9910-1-ming.lei@redhat.com> <20181115085306.9910-10-ming.lei@redhat.com> <20181116134541.GH3165@lst.de> <002fe56b-25e4-573e-c09b-bb12c3e8d25a@grimberg.me> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <002fe56b-25e4-573e-c09b-bb12c3e8d25a@grimberg.me> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Mon, Nov 19, 2018 at 04:49:27PM -0800, Sagi Grimberg wrote: > >> The only user in your final tree seems to be the loop driver, and >> even that one only uses the helper for read/write bios. >> >> I think something like this would be much simpler in the end: > > The recently submitted nvme-tcp host driver should also be a user > of this. Does it make sense to keep it as a helper then? I did take a brief look at the code, and I really don't understand why the heck it even deals with bios to start with. Like all the other nvme transports it is a blk-mq driver and should iterate over segments in a request and more or less ignore bios. Something is horribly wrong in the design.