From: Jason Wang <jasowang@redhat.com>
Date: Wed, 17 May 2017 12:14:43 +0800
Subject: tun: support receiving skb through msg_control
Patch-mainline: v4.13-rc1
Git-commit: ac77cfd4258fb8174766a92d118436da7f9dabf1
References: bsc#1109837
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: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
drivers/net/tun.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1510,9 +1510,8 @@ out:
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_st
if (!iov_iter_count(to))
return 0;
- /* Read frames from ring */
- skb = tun_ring_recv(tfile, noblock, &err);
- if (!skb)
- return err;
+ 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
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 *so
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;