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 11712C4332F for ; Mon, 7 Nov 2022 17:59:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232907AbiKGR7y (ORCPT ); Mon, 7 Nov 2022 12:59:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40262 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232279AbiKGR7i (ORCPT ); Mon, 7 Nov 2022 12:59:38 -0500 Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5CC9B2A40C for ; Mon, 7 Nov 2022 09:56:19 -0800 (PST) Received: from pps.filterd (m0148461.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 2A7Glixl007970 for ; Mon, 7 Nov 2022 09:56:19 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=meta.com; h=from : to : cc : subject : date : message-id : mime-version : content-transfer-encoding : content-type; s=s2048-2021-q4; bh=rKbQINmKWukh6tJOjHplZmnS+uoDK4d+/tWup2ptUOI=; b=QERIf5uzyf0uePa9WfFL07fW4ypnjP0s8jekVkXvgWhdyUTaCLWc5I4lhjWPZLuSplwZ nWdTiZSHbj3Sf//JZxCVNd9YVpXbgHwZKbHZQbgCoc6I1C7+u1vN1qJJ3fnQ54Zw4rND hymXybvrcraJj+4VKnF883NY10Ac75SZLES8e/HPaMz+pMU9XtvF/e/g7G3rUVLAwkHa 7rUH5tbCfkTxYIrYtgj3PJqCa0yRRsI1NoPNpRCMKcZrfjHJHeogSx7QbLDBYvB8zaW3 bvoP2bQvW1FJ9YEf4YD4xZsu5+kNz7V82GVH1READx99gnYhuwTU/1iWUFIwDRnMTXry YA== Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3knmxss1mw-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Mon, 07 Nov 2022 09:56:19 -0800 Received: from twshared27579.05.ash9.facebook.com (2620:10d:c085:208::f) by mail.thefacebook.com (2620:10d:c085:21d::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Mon, 7 Nov 2022 09:56:18 -0800 Received: by devbig007.nao1.facebook.com (Postfix, from userid 544533) id 5C25FADF1C96; Mon, 7 Nov 2022 09:56:11 -0800 (PST) From: Keith Busch To: , , CC: , , Keith Busch Subject: [PATCH 0/4] io_uring: use ITER_UBUF Date: Mon, 7 Nov 2022 09:56:06 -0800 Message-ID: <20221107175610.349807-1-kbusch@meta.com> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-FB-Internal: Safe Content-Type: text/plain X-Proofpoint-ORIG-GUID: 2f06ZlmvkR19rYQhvtRUrTUj6nr31nX- X-Proofpoint-GUID: 2f06ZlmvkR19rYQhvtRUrTUj6nr31nX- X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.219,Aquarius:18.0.895,Hydra:6.0.545,FMLib:17.11.122.1 definitions=2022-11-07_08,2022-11-07_02,2022-06-22_01 Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org From: Keith Busch ITER_UBUF is a more efficient representation when using single vector buffers, providing small optimizations in the fast path. Most of this series came from Jens; I just ported them forward to the current release and tested against various filesystems and devices. Usage for this new iter type has been extensively exercised via read/write syscall interface for some time now, so I don't expect surprises from supporting this with io_uring. There are, however, a couple difference between the two interfaces: 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. =20 2. io_uring will use the ITER_UBUF representation for single vector readv/writev, but the generic syscalls currently uses ITER_IOVEC for these. That should mean, then, the only potential areas for problem are for file_operations that implement both .read/.read_iter or .write/.write_iter. Fortunately there are very few that do that, and I found only two of them that won't readily work: qib_file_ops, and snd_pcm_f_ops. The former is already broken with io_uring before this series, and the latter's vectored read/write only works with ITER_IOVEC, so that will break, but I don't think anyone is using io_uring to talk to a sound card driver. Jens Axboe (3): iov: add import_ubuf() io_uring: switch network send/recv to ITER_UBUF io_uring: use ubuf for single range imports for read/write Keith Busch (1): iov_iter: move iter_ubuf check inside restore WARN include/linux/uio.h | 1 + io_uring/net.c | 13 ++++--------- io_uring/rw.c | 9 ++++++--- lib/iov_iter.c | 15 +++++++++++++-- 4 files changed, 24 insertions(+), 14 deletions(-) --=20 2.30.2