From patchwork Wed Feb 25 14:19:28 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Michael S. Tsirkin" X-Patchwork-Id: 5880421 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 1B48BBF440 for ; Wed, 25 Feb 2015 14:19:54 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 4FB2720381 for ; Wed, 25 Feb 2015 14:19:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6D4172034F for ; Wed, 25 Feb 2015 14:19:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752516AbbBYOTf (ORCPT ); Wed, 25 Feb 2015 09:19:35 -0500 Received: from mx1.redhat.com ([209.132.183.28]:53356 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751963AbbBYOTe (ORCPT ); Wed, 25 Feb 2015 09:19:34 -0500 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id t1PEJVgm021885 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 25 Feb 2015 09:19:31 -0500 Received: from redhat.com (ovpn-116-83.ams2.redhat.com [10.36.116.83]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with SMTP id t1PEJSQn024839; Wed, 25 Feb 2015 09:19:29 -0500 Date: Wed, 25 Feb 2015 15:19:28 +0100 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org Subject: [PATCH] vhost: cleanup iterator update logic Message-ID: <1424873954-16631-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Disposition: inline X-Mutt-Fcc: =sent X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Recent iterator-related changes in vhost made it harder to follow the logic fixing up the header. In fact, the fixup always happens at the same offset: sizeof(virtio_net_hdr): sometimes the fixup iterator is updated by copy_to_iter, sometimes-by iov_iter_advance. Rearrange code to make this obvious. Signed-off-by: Michael S. Tsirkin --- drivers/vhost/net.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index afa06d2..ca70434 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -591,11 +591,6 @@ static void handle_rx(struct vhost_net *net) * TODO: support TSO. */ iov_iter_advance(&msg.msg_iter, vhost_hlen); - } else { - /* It'll come from socket; we'll need to patch - * ->num_buffers over if VIRTIO_NET_F_MRG_RXBUF - */ - iov_iter_advance(&fixup, sizeof(hdr)); } err = sock->ops->recvmsg(NULL, sock, &msg, sock_len, MSG_DONTWAIT | MSG_TRUNC); @@ -609,11 +604,18 @@ static void handle_rx(struct vhost_net *net) continue; } /* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */ - if (unlikely(vhost_hlen) && - copy_to_iter(&hdr, sizeof(hdr), &fixup) != sizeof(hdr)) { - vq_err(vq, "Unable to write vnet_hdr at addr %p\n", - vq->iov->iov_base); - break; + if (unlikely(vhost_hlen)) { + if (copy_to_iter(&hdr, sizeof(hdr), + &fixup) != sizeof(hdr)) { + vq_err(vq, "Unable to write vnet_hdr " + "at addr %p\n", vq->iov->iov_base); + break; + } + } else { + /* Header came from socket; we'll need to patch + * ->num_buffers over if VIRTIO_NET_F_MRG_RXBUF + */ + iov_iter_advance(&fixup, sizeof(hdr)); } /* TODO: Should check and handle checksum. */