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Commit b2430de3 authored by Eric W. Biederman's avatar Eric W. Biederman Committed by David S. Miller
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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: default avatarEric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 38231b7a

drivers/net/tun.c

+10 −8
Original line number Diff line number Diff line
@@ -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;

}