From patchwork Tue Jan 15 10:28:46 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Wang X-Patchwork-Id: 212076 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 99CA02C00A4 for ; Tue, 15 Jan 2013 21:38:19 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756013Ab3AOKiB (ORCPT ); Tue, 15 Jan 2013 05:38:01 -0500 Received: from mx1.redhat.com ([209.132.183.28]:37460 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756803Ab3AOKhT (ORCPT ); Tue, 15 Jan 2013 05:37:19 -0500 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r0FAbIwm019339 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Tue, 15 Jan 2013 05:37:18 -0500 Received: from amd-6168-8-1.englab.nay.redhat.com (amd-6168-8-1.englab.nay.redhat.com [10.66.104.52]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id r0FAb7aS003541; Tue, 15 Jan 2013 05:37:16 -0500 From: Jason Wang To: mst@redhat.com, davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Jason Wang Subject: [PATCH V4 3/3] tuntap: allow polling/writing/reading when detached Date: Tue, 15 Jan 2013 18:28:46 +0800 Message-Id: <1358245726-16250-4-git-send-email-jasowang@redhat.com> In-Reply-To: <1358245726-16250-1-git-send-email-jasowang@redhat.com> References: <1358245726-16250-1-git-send-email-jasowang@redhat.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.12 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org We forbid polling, writing and reading when the file were detached, this may complex the user in several cases: - when guest pass some buffers to vhost/qemu and then disable some queues, vhost/qemu needs to to its own cleanup which is complex. We can do this simply by allowing a user can still write to an disabled queue to handle this. And user can still do read but just nothing returned. - align the polling behavior with macvtap which never fails when the queue is created. this can simplify the polling errors handling of its user (e.g vhost) Signed-off-by: Jason Wang --- drivers/net/tun.c | 18 +++++++++++------- 1 files changed, 11 insertions(+), 7 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index af372d0..eb68937 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -307,7 +307,7 @@ static void tun_flow_update(struct tun_struct *tun, u32 rxhash, rcu_read_lock(); - if (tun->numqueues == 1) + if (tun->numqueues == 1 || queue_index >= tun->numqueues) goto unlock; e = tun_flow_find(head, rxhash); @@ -406,21 +406,21 @@ static void __tun_detach(struct tun_file *tfile, bool clean) tun = rtnl_dereference(tfile->tun); - if (tun) { + if (tun && !tfile->detached) { u16 index = tfile->queue_index; BUG_ON(index >= tun->numqueues); dev = tun->dev; rcu_assign_pointer(tun->tfiles[index], tun->tfiles[tun->numqueues - 1]); - rcu_assign_pointer(tfile->tun, NULL); ntfile = rtnl_dereference(tun->tfiles[index]); ntfile->queue_index = index; --tun->numqueues; - if (clean) + if (clean) { + rcu_assign_pointer(tfile->tun, NULL); sock_put(&tfile->sk); - else + } else tun_disable_queue(tun, tfile); synchronize_net(); @@ -465,6 +465,10 @@ static void tun_detach_all(struct net_device *dev) rcu_assign_pointer(tfile->tun, NULL); --tun->numqueues; } + list_for_each_entry(tfile, &tun->disabled, next) { + wake_up_all(&tfile->wq.wait); + rcu_assign_pointer(tfile->tun, NULL); + } BUG_ON(tun->numqueues != 0); synchronize_net(); @@ -491,7 +495,7 @@ static int tun_attach(struct tun_struct *tun, struct file *file) int err; err = -EINVAL; - if (rtnl_dereference(tfile->tun)) + if (rtnl_dereference(tfile->tun) && !tfile->detached) goto out; err = -EBUSY; @@ -1795,7 +1799,7 @@ static int tun_set_queue(struct file *file, struct ifreq *ifr) ret = tun_attach(tun, file); } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { tun = rtnl_dereference(tfile->tun); - if (!tun || !(tun->flags & TUN_TAP_MQ)) + if (!tun || !(tun->flags & TUN_TAP_MQ) || tfile->detached) ret = -EINVAL; else __tun_detach(tfile, false);