Commit ac77cfd4 authored by Jason Wang's avatar Jason Wang Committed by David S. Miller
Browse files

tun: support receiving skb through msg_control 



This patch makes tun_recvmsg() can receive from skb from its caller
through msg_control. Vhost_net will be the first user.

Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 49f96fd0

drivers/net/tun.c

+10 −8
Original line number Diff line number Diff line
@@ -1510,9 +1510,8 @@ static struct sk_buff *tun_ring_recv(struct tun_file *tfile, int noblock, 


static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,

			   struct iov_iter *to,

			   int noblock)

			   int noblock, struct sk_buff *skb)

{

	struct sk_buff *skb;

	ssize_t ret;

	int err;
@@ -1521,10 +1520,12 @@ static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, 
	if (!iov_iter_count(to))

		return 0;



	if (!skb) {

		/* Read frames from ring */

		skb = tun_ring_recv(tfile, noblock, &err);

		if (!skb)

			return err;

	}



	ret = tun_put_user(tun, tfile, skb, to);

	if (unlikely(ret < 0))
@@ -1544,7 +1545,7 @@ static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to) 


	if (!tun)

		return -EBADFD;

	ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK);

	ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK, NULL);

	ret = min_t(ssize_t, ret, len);

	if (ret > 0)

		iocb->ki_pos = ret;
@@ -1646,7 +1647,8 @@ static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len, 
					 SOL_PACKET, TUN_TX_TIMESTAMP);

		goto out;

	}

	ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT);

	ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT,

			  m->msg_control);

	if (ret > (ssize_t)total_len) {

		m->msg_flags |= MSG_TRUNC;

		ret = flags & MSG_TRUNC ? ret : total_len;