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tun: Move read_wait into tun_file 

The poll interface requires that the waitqueue exist while the struct
file is open.  In the rare case when a tun device disappears before
the tun file closes we fail to provide this property, so move
read_wait.

This is safe now that tun_net_xmit is atomic with tun_detach.

Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric W. Biederman 2009-01-20 11:03:21 +00:00 committed by David S. Miller
parent 38231b7a8d
commit b2430de37e
1 changed files with 10 additions and 8 deletions
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18
drivers/net/tun.c
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@ -90,6 +90,7 @@ struct tap_filter {
struct tun_file {
struct tun_struct *tun;
struct net *net;
wait_queue_head_t read_wait;
};
struct tun_struct {
@ -98,7 +99,6 @@ struct tun_struct {
uid_t owner;
gid_t group;
wait_queue_head_t read_wait;
struct sk_buff_head readq;
struct net_device *dev;
@ -335,7 +335,7 @@ static int tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
/* Notify and wake up reader process */
if (tun->flags & TUN_FASYNC)
kill_fasync(&tun->fasync, SIGIO, POLL_IN);
wake_up_interruptible(&tun->read_wait);
wake_up_interruptible(&tun->tfile->read_wait);
return 0;
drop:
@ -420,7 +420,8 @@ static void tun_net_init(struct net_device *dev)
/* Poll */
static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
{
struct tun_struct *tun = tun_get(file);
struct tun_file *tfile = file->private_data;
struct tun_struct *tun = __tun_get(tfile);
unsigned int mask = POLLOUT | POLLWRNORM;
if (!tun)
@ -428,7 +429,7 @@ static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
DBG(KERN_INFO "%s: tun_chr_poll\n", tun->dev->name);
poll_wait(file, &tun->read_wait, wait);
poll_wait(file, &tfile->read_wait, wait);
if (!skb_queue_empty(&tun->readq))
mask |= POLLIN | POLLRDNORM;
@ -702,7 +703,8 @@ static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
unsigned long count, loff_t pos)
{
struct file *file = iocb->ki_filp;
struct tun_struct *tun = tun_get(file);
struct tun_file *tfile = file->private_data;
struct tun_struct *tun = __tun_get(tfile);
DECLARE_WAITQUEUE(wait, current);
struct sk_buff *skb;
ssize_t len, ret = 0;
@ -718,7 +720,7 @@ static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
goto out;
}
add_wait_queue(&tun->read_wait, &wait);
add_wait_queue(&tfile->read_wait, &wait);
while (len) {
current->state = TASK_INTERRUPTIBLE;
@ -745,7 +747,7 @@ static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
}
current->state = TASK_RUNNING;
remove_wait_queue(&tun->read_wait, &wait);
remove_wait_queue(&tfile->read_wait, &wait);
out:
tun_put(tun);
@ -757,7 +759,6 @@ static void tun_setup(struct net_device *dev)
struct tun_struct *tun = netdev_priv(dev);
skb_queue_head_init(&tun->readq);
init_waitqueue_head(&tun->read_wait);
tun->owner = -1;
tun->group = -1;
@ -1136,6 +1137,7 @@ static int tun_chr_open(struct inode *inode, struct file * file)
return -ENOMEM;
tfile->tun = NULL;
tfile->net = get_net(current->nsproxy->net_ns);
init_waitqueue_head(&tfile->read_wait);
file->private_data = tfile;
return 0;
}