[RFC][b/azure][PATCH 8/8] azure XDP generic fixes - option 1

[Ioanna Alifieraki]

From: Stephen Hemminger <stephen at networkplumber.org>

When a device is stacked like (team, bonding, failsafe or netvsc) the
XDP generic program for the parent device was not called.

Move the call to XDP generic inside __netif_receive_skb_core where
it can be done multiple times for stacked case.

Fixes: d445516966dc ("net: xdp: support xdp generic on virtual devices")
Signed-off-by: Stephen Hemminger <sthemmin at microsoft.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
(backported from commit 458bf2f224f04a513b0be972f8708e78ee2c986e)
[hunk 5 does not apply cleanly beacuse of the different
skb_list_del_init(skb) vs list_del(&skb->list) lines that is removed]
Signed-off-by: Ioanna Alifieraki <ioanna-maria.alifieraki at canonical.com>
---
 net/core/dev.c | 58 +++++++++++---------------------------------------
 1 file changed, 12 insertions(+), 46 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index ccb01cd5cc77..c0d8eeb30b97 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4198,23 +4198,6 @@ 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;
@@ -4543,6 +4526,18 @@ 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);
@@ -4768,19 +4763,6 @@ 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)) {
@@ -4801,7 +4783,6 @@ 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;
 
@@ -4814,21 +4795,6 @@ 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);
-			list_del(&skb->list);
-			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)) {
-- 
2.17.1