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 E0BF0CCA479 for ; Tue, 28 Jun 2022 15:03:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347730AbiF1PDK (ORCPT ); Tue, 28 Jun 2022 11:03:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38934 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347712AbiF1PDC (ORCPT ); Tue, 28 Jun 2022 11:03:02 -0400 Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9323833E9F for ; Tue, 28 Jun 2022 08:03:01 -0700 (PDT) Received: from pps.filterd (m0044010.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 25SAE75B013218 for ; Tue, 28 Jun 2022 08:03:01 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=facebook; bh=yNGWca9EZYptSu02EU61qEdS1WccUVHJPmvgfuLJvJI=; b=PT5C3RKF+bqqbTqcVYEy+XGiQto7YKGGtENqdyg9k/8eyAl4PcD5o1GLCI3d0bcHEiGn 2S4V14Zj70GmXEVnnKDXoePpJF1hxiaC41MDdzd+urLPeHgpg9mdocvLyPYhFJ2SKQtY RmiV/ABNzw4ABTJ42O156r6IXbKSk8MzWYI= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3gyxx31y98-5 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 28 Jun 2022 08:03:01 -0700 Received: from twshared25107.07.ash9.facebook.com (2620:10d:c085:208::11) by mail.thefacebook.com (2620:10d:c085:11d::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.28; Tue, 28 Jun 2022 08:02:55 -0700 Received: by devbig038.lla2.facebook.com (Postfix, from userid 572232) id DAC6E244BBD1; Tue, 28 Jun 2022 08:02:37 -0700 (PDT) From: Dylan Yudaken To: Jens Axboe , Pavel Begunkov , CC: , , Dylan Yudaken Subject: [PATCH for-next 3/8] io_uring: allow iov_len = 0 for recvmsg and buffer select Date: Tue, 28 Jun 2022 08:02:23 -0700 Message-ID: <20220628150228.1379645-4-dylany@fb.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220628150228.1379645-1-dylany@fb.com> References: <20220628150228.1379645-1-dylany@fb.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-FB-Internal: Safe Content-Type: text/plain X-Proofpoint-GUID: lyYIeo1IPJduEjJ32lTdzwqBWSxttULD X-Proofpoint-ORIG-GUID: lyYIeo1IPJduEjJ32lTdzwqBWSxttULD X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.883,Hydra:6.0.517,FMLib:17.11.122.1 definitions=2022-06-28_08,2022-06-28_01,2022-06-22_01 Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org When using BUFFER_SELECT there is no technical requirement that the user actually provides iov, and this removes one copy_from_user call. So allow iov_len to be 0. Signed-off-by: Dylan Yudaken --- io_uring/net.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/io_uring/net.c b/io_uring/net.c index 19a805c3814c..5e84f7ab92a3 100644 --- a/io_uring/net.c +++ b/io_uring/net.c @@ -300,12 +300,18 @@ static int __io_recvmsg_copy_hdr(struct io_kiocb *r= eq, return ret; =20 if (req->flags & REQ_F_BUFFER_SELECT) { - if (iov_len > 1) + if (iov_len =3D=3D 0) { + sr->len =3D iomsg->fast_iov[0].iov_len =3D 0; + iomsg->fast_iov[0].iov_base =3D NULL; + iomsg->free_iov =3D NULL; + } else if (iov_len > 1) { return -EINVAL; - if (copy_from_user(iomsg->fast_iov, uiov, sizeof(*uiov))) - return -EFAULT; - sr->len =3D iomsg->fast_iov[0].iov_len; - iomsg->free_iov =3D NULL; + } else { + if (copy_from_user(iomsg->fast_iov, uiov, sizeof(*uiov))) + return -EFAULT; + sr->len =3D iomsg->fast_iov[0].iov_len; + iomsg->free_iov =3D NULL; + } } else { iomsg->free_iov =3D iomsg->fast_iov; ret =3D __import_iovec(READ, uiov, iov_len, UIO_FASTIOV, --=20 2.30.2