Merge branch 'XDP-transmission-for-tuntap'

Jason Wang says:

====================
XDP transmission for tuntap

This series tries to implement XDP transmission (ndo_xdp_xmit) for
tuntap. Pointer ring was used for queuing both XDP buffers and
sk_buff, this is done by encoding the type into lowest bit of the
pointer and storin XDP metadata in the headroom of XDP buff.

Tests gets 3.05 Mpps when doing xdp_redirect_map from ixgbe to VM
(testpmd + virtio-net in guest). This gives us ~20% improvments
compared to use skb during redirect.

Please review.

Changes from V1:

- slient warnings
- fix typos
- add skb mode number in the commit log
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/tap.c

@@ -330,7 +330,7 @@ rx_handler_result_t tap_handle_frame(struct sk_buff **pskb)
 	if (!q)
 		return RX_HANDLER_PASS;
 
-	if (__skb_array_full(&q->skb_array))
+	if (__ptr_ring_full(&q->ring))
 		goto drop;
 
 	skb_push(skb, ETH_HLEN);
@@ -348,7 +348,7 @@ rx_handler_result_t tap_handle_frame(struct sk_buff **pskb)
 			goto drop;
 
 		if (!segs) {
-			if (skb_array_produce(&q->skb_array, skb))
+			if (ptr_ring_produce(&q->ring, skb))
 				goto drop;
 			goto wake_up;
 		}
@@ -358,7 +358,7 @@ rx_handler_result_t tap_handle_frame(struct sk_buff **pskb)
 			struct sk_buff *nskb = segs->next;
 
 			segs->next = NULL;
-			if (skb_array_produce(&q->skb_array, segs)) {
+			if (ptr_ring_produce(&q->ring, segs)) {
 				kfree_skb(segs);
 				kfree_skb_list(nskb);
 				break;
@@ -375,7 +375,7 @@ rx_handler_result_t tap_handle_frame(struct sk_buff **pskb)
 		    !(features & NETIF_F_CSUM_MASK) &&
 		    skb_checksum_help(skb))
 			goto drop;
-		if (skb_array_produce(&q->skb_array, skb))
+		if (ptr_ring_produce(&q->ring, skb))
 			goto drop;
 	}
 
@@ -497,7 +497,7 @@ static void tap_sock_destruct(struct sock *sk)
 {
 	struct tap_queue *q = container_of(sk, struct tap_queue, sk);
 
-	skb_array_cleanup(&q->skb_array);
+	ptr_ring_cleanup(&q->ring, __skb_array_destroy_skb);
 }
 
 static int tap_open(struct inode *inode, struct file *file)
@@ -517,7 +517,7 @@ static int tap_open(struct inode *inode, struct file *file)
 					     &tap_proto, 0);
 	if (!q)
 		goto err;
-	if (skb_array_init(&q->skb_array, tap->dev->tx_queue_len, GFP_KERNEL)) {
+	if (ptr_ring_init(&q->ring, tap->dev->tx_queue_len, GFP_KERNEL)) {
 		sk_free(&q->sk);
 		goto err;
 	}
@@ -546,7 +546,7 @@ static int tap_open(struct inode *inode, struct file *file)
 
 	err = tap_set_queue(tap, file, q);
 	if (err) {
-		/* tap_sock_destruct() will take care of freeing skb_array */
+		/* tap_sock_destruct() will take care of freeing ptr_ring */
 		goto err_put;
 	}
 
@@ -583,7 +583,7 @@ static unsigned int tap_poll(struct file *file, poll_table *wait)
 	mask = 0;
 	poll_wait(file, &q->wq.wait, wait);
 
-	if (!skb_array_empty(&q->skb_array))
+	if (!ptr_ring_empty(&q->ring))
 		mask |= POLLIN | POLLRDNORM;
 
 	if (sock_writeable(&q->sk) ||
@@ -844,7 +844,7 @@ static ssize_t tap_do_read(struct tap_queue *q,
 					TASK_INTERRUPTIBLE);
 
 		/* Read frames from the queue */
-		skb = skb_array_consume(&q->skb_array);
+		skb = ptr_ring_consume(&q->ring);
 		if (skb)
 			break;
 		if (noblock) {
@@ -1176,7 +1176,7 @@ static int tap_peek_len(struct socket *sock)
 {
 	struct tap_queue *q = container_of(sock, struct tap_queue,
 					       sock);
-	return skb_array_peek_len(&q->skb_array);
+	return PTR_RING_PEEK_CALL(&q->ring, __skb_array_len_with_tag);
 }
 
 /* Ops structure to mimic raw sockets with tun */
@@ -1202,7 +1202,7 @@ struct socket *tap_get_socket(struct file *file)
 }
 EXPORT_SYMBOL_GPL(tap_get_socket);
 
-struct skb_array *tap_get_skb_array(struct file *file)
+struct ptr_ring *tap_get_ptr_ring(struct file *file)
 {
 	struct tap_queue *q;
 
@@ -1211,29 +1211,30 @@ struct skb_array *tap_get_skb_array(struct file *file)
 	q = file->private_data;
 	if (!q)
 		return ERR_PTR(-EBADFD);
-	return &q->skb_array;
+	return &q->ring;
 }
-EXPORT_SYMBOL_GPL(tap_get_skb_array);
+EXPORT_SYMBOL_GPL(tap_get_ptr_ring);
 
 int tap_queue_resize(struct tap_dev *tap)
 {
 	struct net_device *dev = tap->dev;
 	struct tap_queue *q;
-	struct skb_array **arrays;
+	struct ptr_ring **rings;
 	int n = tap->numqueues;
 	int ret, i = 0;
 
-	arrays = kmalloc_array(n, sizeof(*arrays), GFP_KERNEL);
-	if (!arrays)
+	rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
+	if (!rings)
 		return -ENOMEM;
 
 	list_for_each_entry(q, &tap->queue_list, next)
-		arrays[i++] = &q->skb_array;
+		rings[i++] = &q->ring;
 
-	ret = skb_array_resize_multiple(arrays, n,
-					dev->tx_queue_len, GFP_KERNEL);
+	ret = ptr_ring_resize_multiple(rings, n,
+				       dev->tx_queue_len, GFP_KERNEL,
+				       __skb_array_destroy_skb);
 
-	kfree(arrays);
+	kfree(rings);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(tap_queue_resize);