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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 2186EC4BA13 for ; Wed, 26 Feb 2020 16:53:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E7AA221556 for ; Wed, 26 Feb 2020 16:53:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Ke3zHlRT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726810AbgBZQxK (ORCPT ); Wed, 26 Feb 2020 11:53:10 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:45226 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726151AbgBZQxK (ORCPT ); Wed, 26 Feb 2020 11:53:10 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; 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=lw5ZJrF2vLLzt6YlgdJXV18NDddK/UjL52iREY7XGmI=; b=Ke3zHlRT0xx9Z7vYEyotlimGp2 BFD9Y++ZwQbhing5NTQQmRQD/CXn/J7mT4nzLxpK+5adnu7fVZ2B9XTUpSkfPSFsW9XwVxnkAFgmR eBjVNQbP4uNKGXORLkIOb71jxR+ZgTNWiF4rKd3xZwfUxDekydVOsOIDLsG/hWuhjcz+JaD6SBnEa 1E2ZkJNDeApgacLPm7+XUqCiGpvVfkaRwvM0wnR1mdorDc3mwTTioNUGTsn1fgURSOSvj0U6DMqHv tIvycu3gR+pYR3/haLCxNGU0Aks2pxTghWEVkp8lfAbVMUKXHng7sFVCTSxBQcvcvGCM4RkEkVbeo nfPTW35g==; Received: from hch by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1j6zvp-0001O9-8M; Wed, 26 Feb 2020 16:53:09 +0000 Date: Wed, 26 Feb 2020 08:53:09 -0800 From: Christoph Hellwig To: Jens Axboe Cc: Christoph Hellwig , Bob Liu , linux-block@vger.kernel.org, martin.petersen@oracle.com, linux-fsdevel@vger.kernel.org, darrick.wong@oracle.com, io-uring@vger.kernel.org Subject: Re: [PATCH 1/4] io_uring: add IORING_OP_READ{WRITE}V_PI cmd Message-ID: <20200226165309.GA3995@infradead.org> References: <20200226083719.4389-1-bob.liu@oracle.com> <20200226083719.4389-2-bob.liu@oracle.com> <6e466774-4dc5-861c-58b5-f0cc728bacff@kernel.dk> <20200226155728.GA32543@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On Wed, Feb 26, 2020 at 08:58:46AM -0700, Jens Axboe wrote: > Yeah, should probably be a RWF_ flag instead, and a 64-bit SQE field > for the PI data. The 'last iovec is PI' is kind of icky. Abusing an iovec (although I though of the first once when looking into it) looks really horrible, but has two huge advantages: - it doesn't require passing another argument all the way down the I/O stack - it works with all the vectored interfaces that take a flag argument, so not just io_uring, but also preadv2/pwritev2 and aio. And while I don't care too much about the last I think preadv2 and pwritev2 are valuable to support.