Messages in this thread Patch in this message | | | From | Jason Wang <> | Subject | [PATCH V4 3/3] tuntap: allow polling/writing/reading when detached | Date | Tue, 15 Jan 2013 18:28:46 +0800 |
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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 <jasowang@redhat.com> --- 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); -- 1.7.1
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