net/mlx4_en: call gro handler for encapsulated frames

In order to use the native GRO handling of encapsulated protocols on
mlx4, we need to call napi_gro_receive() instead of netif_receive_skb()
unless busy polling is in action.

While we are at it, rename mlx4_en_cq_ll_polling() to
mlx4_en_cq_busy_polling()

Tested with GRE tunnel : GRO aggregation is now performed on the
ethernet device instead of being done later on gre device.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Amir Vadai <amirv@mellanox.com>
Cc: Jerry Chu <hkchu@google.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Acked-By: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/en_rx.c

@@ -724,7 +724,7 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud
 				 * - not an IP fragment
 				 * - no LLS polling in progress
 				 */
-				if (!mlx4_en_cq_ll_polling(cq) &&
+				if (!mlx4_en_cq_busy_polling(cq) &&
 				    (dev->features & NETIF_F_GRO)) {
 					struct sk_buff *gro_skb = napi_get_frags(&cq->napi);
 					if (!gro_skb)
@@ -816,8 +816,10 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud
 
 		skb_mark_napi_id(skb, &cq->napi);
 
-		/* Push it up the stack */
-		netif_receive_skb(skb);
+		if (!mlx4_en_cq_busy_polling(cq))
+			napi_gro_receive(&cq->napi, skb);
+		else
+			netif_receive_skb(skb);
 
 next:
 		for (nr = 0; nr < priv->num_frags; nr++)

drivers/net/ethernet/mellanox/mlx4/mlx4_en.h

@@ -661,7 +661,7 @@ static inline bool mlx4_en_cq_unlock_poll(struct mlx4_en_cq *cq)
 }
 
 /* true if a socket is polling, even if it did not get the lock */
-static inline bool mlx4_en_cq_ll_polling(struct mlx4_en_cq *cq)
+static inline bool mlx4_en_cq_busy_polling(struct mlx4_en_cq *cq)
 {
 	WARN_ON(!(cq->state & MLX4_CQ_LOCKED));
 	return cq->state & CQ_USER_PEND;
@@ -691,7 +691,7 @@ static inline bool mlx4_en_cq_unlock_poll(struct mlx4_en_cq *cq)
 	return false;
 }
 
-static inline bool mlx4_en_cq_ll_polling(struct mlx4_en_cq *cq)
+static inline bool mlx4_en_cq_busy_polling(struct mlx4_en_cq *cq)
 {
 	return false;
 }