Merge branch 'XDP-generic-fixes'

Stephen Hemminger says:

====================
XDP generic fixes

This set of patches came about while investigating XDP
generic on Azure. The split brain nature of the accelerated
networking exposed issues with the stack device model.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/hyperv/netvsc_drv.c

@@ -2000,6 +2000,12 @@ static rx_handler_result_t netvsc_vf_handle_frame(struct sk_buff **pskb)
 	struct netvsc_vf_pcpu_stats *pcpu_stats
 		 = this_cpu_ptr(ndev_ctx->vf_stats);
 
+	skb = skb_share_check(skb, GFP_ATOMIC);
+	if (unlikely(!skb))
+		return RX_HANDLER_CONSUMED;
+
+	*pskb = skb;
+
 	skb->dev = ndev;
 
 	u64_stats_update_begin(&pcpu_stats->syncp);

net/core/dev.c

@@ -4502,23 +4502,6 @@ static int netif_rx_internal(struct sk_buff *skb)
 
 	trace_netif_rx(skb);
 
-	if (static_branch_unlikely(&generic_xdp_needed_key)) {
-		int ret;
-
-		preempt_disable();
-		rcu_read_lock();
-		ret = do_xdp_generic(rcu_dereference(skb->dev->xdp_prog), skb);
-		rcu_read_unlock();
-		preempt_enable();
-
-		/* Consider XDP consuming the packet a success from
-		 * the netdev point of view we do not want to count
-		 * this as an error.
-		 */
-		if (ret != XDP_PASS)
-			return NET_RX_SUCCESS;
-	}
-
 #ifdef CONFIG_RPS
 	if (static_branch_unlikely(&rps_needed)) {
 		struct rps_dev_flow voidflow, *rflow = &voidflow;
@@ -4858,6 +4841,18 @@ static int __netif_receive_skb_core(struct sk_buff *skb, bool pfmemalloc,
 
 	__this_cpu_inc(softnet_data.processed);
 
+	if (static_branch_unlikely(&generic_xdp_needed_key)) {
+		int ret2;
+
+		preempt_disable();
+		ret2 = do_xdp_generic(rcu_dereference(skb->dev->xdp_prog), skb);
+		preempt_enable();
+
+		if (ret2 != XDP_PASS)
+			return NET_RX_DROP;
+		skb_reset_mac_len(skb);
+	}
+
 	if (skb->protocol == cpu_to_be16(ETH_P_8021Q) ||
 	    skb->protocol == cpu_to_be16(ETH_P_8021AD)) {
 		skb = skb_vlan_untag(skb);
@@ -5178,19 +5173,6 @@ static int netif_receive_skb_internal(struct sk_buff *skb)
 	if (skb_defer_rx_timestamp(skb))
 		return NET_RX_SUCCESS;
 
-	if (static_branch_unlikely(&generic_xdp_needed_key)) {
-		int ret;
-
-		preempt_disable();
-		rcu_read_lock();
-		ret = do_xdp_generic(rcu_dereference(skb->dev->xdp_prog), skb);
-		rcu_read_unlock();
-		preempt_enable();
-
-		if (ret != XDP_PASS)
-			return NET_RX_DROP;
-	}
-
 	rcu_read_lock();
 #ifdef CONFIG_RPS
 	if (static_branch_unlikely(&rps_needed)) {
@@ -5211,7 +5193,6 @@ static int netif_receive_skb_internal(struct sk_buff *skb)
 
 static void netif_receive_skb_list_internal(struct list_head *head)
 {
-	struct bpf_prog *xdp_prog = NULL;
 	struct sk_buff *skb, *next;
 	struct list_head sublist;
 
@@ -5224,21 +5205,6 @@ static void netif_receive_skb_list_internal(struct list_head *head)
 	}
 	list_splice_init(&sublist, head);
 
-	if (static_branch_unlikely(&generic_xdp_needed_key)) {
-		preempt_disable();
-		rcu_read_lock();
-		list_for_each_entry_safe(skb, next, head, list) {
-			xdp_prog = rcu_dereference(skb->dev->xdp_prog);
-			skb_list_del_init(skb);
-			if (do_xdp_generic(xdp_prog, skb) == XDP_PASS)
-				list_add_tail(&skb->list, &sublist);
-		}
-		rcu_read_unlock();
-		preempt_enable();
-		/* Put passed packets back on main list */
-		list_splice_init(&sublist, head);
-	}
-
 	rcu_read_lock();
 #ifdef CONFIG_RPS
 	if (static_branch_unlikely(&rps_needed)) {