tuntap: set SOCK_ZEROCOPY flag during open

Commit 54f968d6efdbf7dec36faa44fc11f01b0e4d1990
(tuntap: move socket to tun_file) forgets to set SOCK_ZEROCOPY flag, which will
prevent vhost_net from doing zercopy w/ tap. This patch fixes this by setting
it during file open.

Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index b1cbfbcff789..bfa9bb48e42d 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -2159,6 +2159,8 @@ static int tun_chr_open(struct inode *inode, struct file * file)
         set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags);
         INIT_LIST_HEAD(&tfile->next);
 
+        sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
+
         return 0;
 }