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Commit 3b4ba04a authored by Jason Wang's avatar Jason Wang Committed by David S. Miller
Browse files

tap: support receiving skb from msg_control 



This patch makes tap_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 ac77cfd4

drivers/net/tap.c

+8 −4
Original line number Diff line number Diff line
@@ -824,15 +824,17 @@ static ssize_t tap_put_user(struct tap_queue *q, 


static ssize_t tap_do_read(struct tap_queue *q,

			   struct iov_iter *to,

			   int noblock)

			   int noblock, struct sk_buff *skb)

{

	DEFINE_WAIT(wait);

	struct sk_buff *skb;

	ssize_t ret = 0;



	if (!iov_iter_count(to))

		return 0;



	if (skb)

		goto put;



	while (1) {

		if (!noblock)

			prepare_to_wait(sk_sleep(&q->sk), &wait,
@@ -856,6 +858,7 @@ static ssize_t tap_do_read(struct tap_queue *q, 
	if (!noblock)

		finish_wait(sk_sleep(&q->sk), &wait);



put:

	if (skb) {

		ret = tap_put_user(q, skb, to);

		if (unlikely(ret < 0))
@@ -872,7 +875,7 @@ static ssize_t tap_read_iter(struct kiocb *iocb, struct iov_iter *to) 
	struct tap_queue *q = file->private_data;

	ssize_t len = iov_iter_count(to), ret;



	ret = tap_do_read(q, to, file->f_flags & O_NONBLOCK);

	ret = tap_do_read(q, to, file->f_flags & O_NONBLOCK, NULL);

	ret = min_t(ssize_t, ret, len);

	if (ret > 0)

		iocb->ki_pos = ret;
@@ -1155,7 +1158,8 @@ static int tap_recvmsg(struct socket *sock, struct msghdr *m, 
	int ret;

	if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))

		return -EINVAL;

	ret = tap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT);

	ret = tap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT,

			  m->msg_control);

	if (ret > total_len) {

		m->msg_flags |= MSG_TRUNC;

		ret = flags & MSG_TRUNC ? ret : total_len;