diff options
| -rw-r--r-- | drivers/net/tun.c | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index d45ac37e1287..45d807796a18 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1423,6 +1423,13 @@ static void tun_net_init(struct net_device *dev) dev->max_mtu = MAX_MTU - dev->hard_header_len; } +static bool tun_sock_writeable(struct tun_struct *tun, struct tun_file *tfile) +{ + struct sock *sk = tfile->socket.sk; + + return (tun->dev->flags & IFF_UP) && sock_writeable(sk); +} + /* Character device part */ /* Poll */ @@ -1445,10 +1452,14 @@ static __poll_t tun_chr_poll(struct file *file, poll_table *wait) if (!ptr_ring_empty(&tfile->tx_ring)) mask |= EPOLLIN | EPOLLRDNORM; - if (tun->dev->flags & IFF_UP && - (sock_writeable(sk) || - (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) && - sock_writeable(sk)))) + /* Make sure SOCKWQ_ASYNC_NOSPACE is set if not writable to + * guarantee EPOLLOUT to be raised by either here or + * tun_sock_write_space(). Then process could get notification + * after it writes to a down device and meets -EIO. + */ + if (tun_sock_writeable(tun, tfile) || + (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) && + tun_sock_writeable(tun, tfile))) mask |= EPOLLOUT | EPOLLWRNORM; if (tun->dev->reg_state != NETREG_REGISTERED) |