[PATCH 4.15 061/122] net/mlx5e: Fix loopback self test when GRO is off

[Greg Kroah-Hartman]

4.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Inbar Karmy <inbark@xxxxxxxxxxxx>


[ Upstream commit ef7a3518f7dd4f4cf5e5b5358c93d1eb78df28fb ]

When GRO is off, the transport header pointer in sk_buff is
initialized to network's header.

To find the udp header, instead of using udp_hdr() which assumes
skb_network_header was set, manually calculate the udp header offset.

Fixes: 0952da791c97 ("net/mlx5e: Add support for loopback selftest")
Signed-off-by: Inbar Karmy <inbark@xxxxxxxxxxxx>
Signed-off-by: Saeed Mahameed <saeedm@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_selftest.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/en_selftest.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_selftest.c
@@ -216,7 +216,8 @@ mlx5e_test_loopback_validate(struct sk_b
 	if (iph->protocol != IPPROTO_UDP)
 		goto out;
 
-	udph = udp_hdr(skb);
+	/* Don't assume skb_transport_header() was set */
+	udph = (struct udphdr *)((u8 *)iph + 4 * iph->ihl);
 	if (udph->dest != htons(9))
 		goto out;