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tun: wake up waitqueues after IFF_UP is set

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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>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Fei Li 2019-06-17 21:26:36 +08:00 committed by David S. Miller
parent d0bae4a0e3
commit 72b319dc08
1 changed files with 9 additions and 10 deletions
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19
drivers/net/tun.c
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@ -1014,18 +1014,8 @@ static void tun_net_uninit(struct net_device *dev)
/* Net device open. */
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 +3624,7 @@ 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 +3634,14 @@ 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;
}