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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7C72DC4332F for ; Tue, 8 Nov 2022 06:54:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233352AbiKHGyM (ORCPT ); Tue, 8 Nov 2022 01:54:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50922 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229478AbiKHGyM (ORCPT ); Tue, 8 Nov 2022 01:54:12 -0500 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9ACD31F639; Mon, 7 Nov 2022 22:54:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=VOakFTCaKuLEv2D82OsubD8D3LPFiH3ckd5BU32nB6c=; b=zQYXaJOW6FGyL9jF7Lhii2muZj TeEqbO6rv/5PGxbx49t18GEjv3piBdOQDek931YO+oLwtD6q1Z1G9+8cRntrKgteUYTJXjsdqTlaX 9SIaWNE+Ugr0mmvcWtfDPTLTht/oyqbbX3mCY66ozEPg5D4mHJXh3iCLobh00HFEOeWABjbr1GhCW 18teDAk+mv+XHHjawk1EDAILFyW2G/tW5b3AFDBYhbB+f4Wq/C6HBBkfXblTJUWyx9DwrZVqYqS5N po7N+aR3GbeUswvMsPzfSFd6vOi2C9XuddOhN/GqbueiyoVGNkrukfXq1Spx1SdLNftCYtDhJH0Qu moljlSFg==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1osIUo-003IJZ-Bs; Tue, 08 Nov 2022 06:54:06 +0000 Date: Mon, 7 Nov 2022 22:54:06 -0800 From: Christoph Hellwig To: Keith Busch Cc: viro@zeniv.linux.org.uk, axboe@kernel.dk, io-uring@vger.kernel.org, asml.silence@gmail.com, linux-fsdevel@vger.kernel.org, Keith Busch Subject: Re: [PATCH 0/4] io_uring: use ITER_UBUF Message-ID: References: <20221107175610.349807-1-kbusch@meta.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221107175610.349807-1-kbusch@meta.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On Mon, Nov 07, 2022 at 09:56:06AM -0800, Keith Busch wrote: > 1. io_uring will always prefer using the _iter versions of read/write > callbacks if file_operations implement both, where as the generic > syscalls will use .read/.write (if implemented) for non-vectored IO. There are very few file operations that have both, and for those the difference matters, e.g. the strange vectors semantics for the sound code. I would strongly suggest to mirror what the normal read/write path does here. > 2. io_uring will use the ITER_UBUF representation for single vector > readv/writev, but the generic syscalls currently uses ITER_IOVEC for > these. Same here. It might be woth to use ITER_UBUF for single vector readv/writev, but this should be the same for all interfaces. I'd suggest to drop this for now and do a separate series with careful review from Al for this.