Messages in this thread | | | Subject | Re: [PATCH] Fix tun: wake up waitqueues after IFF_UP is set | From | Jason Wang <> | Date | Mon, 17 Jun 2019 16:10:12 +0800 |
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On 2019/6/17 下午3:33, Fei Li wrote: > Currently after setting tap0 link up, the tun code wakes tx/rx waited > queues up in tun_net_open() when .ndo_open() is called, however the > IFF_UP flag has not been set yet. If there's already a wait queue, it > would fail to transmit when checking the IFF_UP flag in tun_sendmsg(). > Then the saving vhost_poll_start() will add the wq into wqh until it > is waken up again. Although this works when IFF_UP flag has been set > when tun_chr_poll detects; this is not true if IFF_UP flag has not > been set at that time. Sadly the latter case is a fatal error, as > the wq will never be waken up in future unless later manually > setting link up on purpose. > > Fix this by moving the wakeup process into the NETDEV_UP event > notifying process, this makes sure IFF_UP has been set before all > waited queues been waken up. > > Signed-off-by: Fei Li <lifei.shirley@bytedance.com> > --- > drivers/net/tun.c | 17 +++++++++-------- > 1 file changed, 9 insertions(+), 8 deletions(-) > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index c452d6d831dd..a3c9cab5a4d0 100644 > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -1015,17 +1015,9 @@ static void tun_net_uninit(struct net_device *dev) > static int tun_net_open(struct net_device *dev) > { > struct tun_struct *tun = netdev_priv(dev); > - int i; > > netif_tx_start_all_queues(dev); > > - for (i = 0; i < tun->numqueues; i++) { > - struct tun_file *tfile; > - > - tfile = rtnl_dereference(tun->tfiles[i]); > - tfile->socket.sk->sk_write_space(tfile->socket.sk); > - } > - > return 0; > } > > @@ -3634,6 +3626,7 @@ static int tun_device_event(struct notifier_block *unused, > { > struct net_device *dev = netdev_notifier_info_to_dev(ptr); > struct tun_struct *tun = netdev_priv(dev); > + int i; > > if (dev->rtnl_link_ops != &tun_link_ops) > return NOTIFY_DONE; > @@ -3643,6 +3636,14 @@ static int tun_device_event(struct notifier_block *unused, > if (tun_queue_resize(tun)) > return NOTIFY_BAD; > break; > + case NETDEV_UP: > + for (i = 0; i < tun->numqueues; i++) { > + struct tun_file *tfile; > + > + tfile = rtnl_dereference(tun->tfiles[i]); > + tfile->socket.sk->sk_write_space(tfile->socket.sk); > + } > + break; > default: > break; > }
Acked-by: Jason Wang <jasowang@redhat.com)
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