diff options
| -rw-r--r-- | drivers/net/tun.c | 50 |
1 files changed, 48 insertions, 2 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 030d9858bb6..51dba6192ba 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -88,6 +88,7 @@ struct tap_filter { }; struct tun_file { + atomic_t count; struct tun_struct *tun; struct net *net; wait_queue_head_t read_wait; @@ -138,6 +139,8 @@ static int tun_attach(struct tun_struct *tun, struct file *file) err = 0; tfile->tun = tun; tun->tfile = tfile; + dev_hold(tun->dev); + atomic_inc(&tfile->count); out: netif_tx_unlock_bh(tun->dev); @@ -156,11 +159,26 @@ static void __tun_detach(struct tun_struct *tun) /* Drop read queue */ skb_queue_purge(&tun->readq); + + /* Drop the extra count on the net device */ + dev_put(tun->dev); +} + +static void tun_detach(struct tun_struct *tun) +{ + rtnl_lock(); + __tun_detach(tun); + rtnl_unlock(); } static struct tun_struct *__tun_get(struct tun_file *tfile) { - return tfile->tun; + struct tun_struct *tun = NULL; + + if (atomic_inc_not_zero(&tfile->count)) + tun = tfile->tun; + + return tun; } static struct tun_struct *tun_get(struct file *file) @@ -170,7 +188,10 @@ static struct tun_struct *tun_get(struct file *file) static void tun_put(struct tun_struct *tun) { - /* Noop for now */ + struct tun_file *tfile = tun->tfile; + + if (atomic_dec_and_test(&tfile->count)) + tun_detach(tfile->tun); } /* TAP filterting */ @@ -281,6 +302,21 @@ static int check_filter(struct tap_filter *filter, const struct sk_buff *skb) static const struct ethtool_ops tun_ethtool_ops; +/* Net device detach from fd. */ +static void tun_net_uninit(struct net_device *dev) +{ + struct tun_struct *tun = netdev_priv(dev); + struct tun_file *tfile = tun->tfile; + + /* Inform the methods they need to stop using the dev. + */ + if (tfile) { + wake_up_all(&tfile->read_wait); + if (atomic_dec_and_test(&tfile->count)) + __tun_detach(tun); + } +} + /* Net device open. */ static int tun_net_open(struct net_device *dev) { @@ -367,6 +403,7 @@ tun_net_change_mtu(struct net_device *dev, int new_mtu) } static const struct net_device_ops tun_netdev_ops = { + .ndo_uninit = tun_net_uninit, .ndo_open = tun_net_open, .ndo_stop = tun_net_close, .ndo_start_xmit = tun_net_xmit, @@ -374,6 +411,7 @@ static const struct net_device_ops tun_netdev_ops = { }; static const struct net_device_ops tap_netdev_ops = { + .ndo_uninit = tun_net_uninit, .ndo_open = tun_net_open, .ndo_stop = tun_net_close, .ndo_start_xmit = tun_net_xmit, @@ -434,6 +472,9 @@ static unsigned int tun_chr_poll(struct file *file, poll_table * wait) if (!skb_queue_empty(&tun->readq)) mask |= POLLIN | POLLRDNORM; + if (tun->dev->reg_state != NETREG_REGISTERED) + mask = POLLERR; + tun_put(tun); return mask; } @@ -734,6 +775,10 @@ static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv, ret = -ERESTARTSYS; break; } + if (tun->dev->reg_state != NETREG_REGISTERED) { + ret = -EIO; + break; + } /* Nothing to read, let's sleep */ schedule(); @@ -1135,6 +1180,7 @@ static int tun_chr_open(struct inode *inode, struct file * file) tfile = kmalloc(sizeof(*tfile), GFP_KERNEL); if (!tfile) return -ENOMEM; + atomic_set(&tfile->count, 0); tfile->tun = NULL; tfile->net = get_net(current->nsproxy->net_ns); init_waitqueue_head(&tfile->read_wait); |