• Fei Li's avatar
    tun: wake up waitqueues after IFF_UP is set · 72b319dc
    Fei Li authored
    
    
    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: default avatarFei Li <lifei.shirley@bytedance.com>
    Acked-by: default avatarJason Wang <jasowang@redhat.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    72b319dc