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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 8214FC19425 for ; Wed, 9 Dec 2020 13:08:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4177F23BC7 for ; Wed, 9 Dec 2020 13:08:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732188AbgLINIU (ORCPT ); Wed, 9 Dec 2020 08:08:20 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52070 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732178AbgLINIL (ORCPT ); Wed, 9 Dec 2020 08:08:11 -0500 Received: from ZenIV.linux.org.uk (zeniv.linux.org.uk [IPv6:2002:c35c:fd02::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 39598C0613D6; Wed, 9 Dec 2020 05:07:31 -0800 (PST) Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kmzBj-0003sZ-21; Wed, 09 Dec 2020 13:07:23 +0000 Date: Wed, 9 Dec 2020 13:07:23 +0000 From: Al Viro To: Christoph Hellwig Cc: Pavel Begunkov , Jens Axboe , linux-fsdevel@vger.kernel.org, io-uring@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] iov: introduce ITER_BVEC_FLAG_FIXED Message-ID: <20201209130723.GL3579531@ZenIV.linux.org.uk> References: <20201209083645.GB21968@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201209083645.GB21968@infradead.org> Sender: Al Viro Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On Wed, Dec 09, 2020 at 08:36:45AM +0000, Christoph Hellwig wrote: > > This is making the iter type even more of a mess than it already is. > I think we at least need placeholders for 0/1 here and an explicit > flags namespace, preferably after the types. > > Then again I'd much prefer if we didn't even add the flag or at best > just add it for a short-term transition and move everyone over to the > new scheme. Otherwise the amount of different interfaces and supporting > code keeps exploding. Yes. The only problem I see is how to describe the rules - "bdev-backed iterators need the bvec array to stay allocated until IO completes"? And one way or another, that needs to be documented - D/f/porting with "mandatory" for priority.