Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/net/tap.c b/drivers/net/tap.c
index f0f7cd9..3ae70c7 100644
--- a/drivers/net/tap.c
+++ b/drivers/net/tap.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 #include <linux/etherdevice.h>
 #include <linux/if_tap.h>
 #include <linux/if_vlan.h>
@@ -519,8 +520,7 @@
 		goto err;
 	}
 
-	RCU_INIT_POINTER(q->sock.wq, &q->wq);
-	init_waitqueue_head(&q->wq.wait);
+	init_waitqueue_head(&q->sock.wq.wait);
 	q->sock.type = SOCK_RAW;
 	q->sock.state = SS_CONNECTED;
 	q->sock.file = file;
@@ -578,7 +578,7 @@
 		goto out;
 
 	mask = 0;
-	poll_wait(file, &q->wq.wait, wait);
+	poll_wait(file, &q->sock.wq.wait, wait);
 
 	if (!ptr_ring_empty(&q->ring))
 		mask |= EPOLLIN | EPOLLRDNORM;
@@ -619,7 +619,7 @@
 #define TAP_RESERVE HH_DATA_OFF(ETH_HLEN)
 
 /* Get packet from user space buffer */
-static ssize_t tap_get_user(struct tap_queue *q, struct msghdr *m,
+static ssize_t tap_get_user(struct tap_queue *q, void *msg_control,
 			    struct iov_iter *from, int noblock)
 {
 	int good_linear = SKB_MAX_HEAD(TAP_RESERVE);
@@ -663,7 +663,7 @@
 	if (unlikely(len < ETH_HLEN))
 		goto err;
 
-	if (m && m->msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY)) {
+	if (msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY)) {
 		struct iov_iter i;
 
 		copylen = vnet_hdr.hdr_len ?
@@ -712,7 +712,7 @@
 			goto err_kfree;
 	}
 
-	skb_probe_transport_header(skb, ETH_HLEN);
+	skb_probe_transport_header(skb);
 
 	/* Move network header to the right position for VLAN tagged packets */
 	if ((skb->protocol == htons(ETH_P_8021Q) ||
@@ -724,11 +724,11 @@
 	tap = rcu_dereference(q->tap);
 	/* copy skb_ubuf_info for callback when skb has no error */
 	if (zerocopy) {
-		skb_shinfo(skb)->destructor_arg = m->msg_control;
+		skb_shinfo(skb)->destructor_arg = msg_control;
 		skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
 		skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
-	} else if (m && m->msg_control) {
-		struct ubuf_info *uarg = m->msg_control;
+	} else if (msg_control) {
+		struct ubuf_info *uarg = msg_control;
 		uarg->callback(uarg, false);
 	}
 
@@ -830,8 +830,7 @@
 	ssize_t ret = 0;
 
 	if (!iov_iter_count(to)) {
-		if (skb)
-			kfree_skb(skb);
+		kfree_skb(skb);
 		return 0;
 	}
 
@@ -1114,7 +1113,7 @@
 			rtnl_unlock();
 			return -ENOLINK;
 		}
-		ret = dev_set_mac_address(tap->dev, &sa);
+		ret = dev_set_mac_address(tap->dev, &sa, NULL);
 		tap_put_tap_dev(tap);
 		rtnl_unlock();
 		return ret;
@@ -1146,11 +1145,86 @@
 #endif
 };
 
+static int tap_get_user_xdp(struct tap_queue *q, struct xdp_buff *xdp)
+{
+	struct tun_xdp_hdr *hdr = xdp->data_hard_start;
+	struct virtio_net_hdr *gso = &hdr->gso;
+	int buflen = hdr->buflen;
+	int vnet_hdr_len = 0;
+	struct tap_dev *tap;
+	struct sk_buff *skb;
+	int err, depth;
+
+	if (q->flags & IFF_VNET_HDR)
+		vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz);
+
+	skb = build_skb(xdp->data_hard_start, buflen);
+	if (!skb) {
+		err = -ENOMEM;
+		goto err;
+	}
+
+	skb_reserve(skb, xdp->data - xdp->data_hard_start);
+	skb_put(skb, xdp->data_end - xdp->data);
+
+	skb_set_network_header(skb, ETH_HLEN);
+	skb_reset_mac_header(skb);
+	skb->protocol = eth_hdr(skb)->h_proto;
+
+	if (vnet_hdr_len) {
+		err = virtio_net_hdr_to_skb(skb, gso, tap_is_little_endian(q));
+		if (err)
+			goto err_kfree;
+	}
+
+	/* Move network header to the right position for VLAN tagged packets */
+	if ((skb->protocol == htons(ETH_P_8021Q) ||
+	     skb->protocol == htons(ETH_P_8021AD)) &&
+	    __vlan_get_protocol(skb, skb->protocol, &depth) != 0)
+		skb_set_network_header(skb, depth);
+
+	rcu_read_lock();
+	tap = rcu_dereference(q->tap);
+	if (tap) {
+		skb->dev = tap->dev;
+		skb_probe_transport_header(skb);
+		dev_queue_xmit(skb);
+	} else {
+		kfree_skb(skb);
+	}
+	rcu_read_unlock();
+
+	return 0;
+
+err_kfree:
+	kfree_skb(skb);
+err:
+	rcu_read_lock();
+	tap = rcu_dereference(q->tap);
+	if (tap && tap->count_tx_dropped)
+		tap->count_tx_dropped(tap);
+	rcu_read_unlock();
+	return err;
+}
+
 static int tap_sendmsg(struct socket *sock, struct msghdr *m,
 		       size_t total_len)
 {
 	struct tap_queue *q = container_of(sock, struct tap_queue, sock);
-	return tap_get_user(q, m, &m->msg_iter, m->msg_flags & MSG_DONTWAIT);
+	struct tun_msg_ctl *ctl = m->msg_control;
+	struct xdp_buff *xdp;
+	int i;
+
+	if (ctl && (ctl->type == TUN_MSG_PTR)) {
+		for (i = 0; i < ctl->num; i++) {
+			xdp = &((struct xdp_buff *)ctl->ptr)[i];
+			tap_get_user_xdp(q, xdp);
+		}
+		return 0;
+	}
+
+	return tap_get_user(q, ctl ? ctl->ptr : NULL, &m->msg_iter,
+			    m->msg_flags & MSG_DONTWAIT);
 }
 
 static int tap_recvmsg(struct socket *sock, struct msghdr *m,
@@ -1160,8 +1234,7 @@
 	struct sk_buff *skb = m->msg_control;
 	int ret;
 	if (flags & ~(MSG_DONTWAIT|MSG_TRUNC)) {
-		if (skb)
-			kfree_skb(skb);
+		kfree_skb(skb);
 		return -EINVAL;
 	}
 	ret = tap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT, skb);