[PATCH 4.12 30/52] net/mlx5e: Fix inline header size for small packets

[Greg Kroah-Hartman]

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

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

From: Moshe Shemesh <moshe@xxxxxxxxxxxx>


[ Upstream commit 6aace17e64f4aa1c49802c46bd10688968b3787f ]

Fix inline header size, make sure it is not greater than skb len.
This bug effects small packets, for example L2 packets with size < 18.

Fixes: ae76715d153e ("net/mlx5e: Check the minimum inline header mode before xmit")
Signed-off-by: Moshe Shemesh <moshe@xxxxxxxxxxxx>
Signed-off-by: Saeed Mahameed <saeedm@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_tx.c |   17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
@@ -127,10 +127,10 @@ static inline int mlx5e_skb_l3_header_of
 		return mlx5e_skb_l2_header_offset(skb);
 }
 
-static inline unsigned int mlx5e_calc_min_inline(enum mlx5_inline_modes mode,
-						 struct sk_buff *skb)
+static inline u16 mlx5e_calc_min_inline(enum mlx5_inline_modes mode,
+					struct sk_buff *skb)
 {
-	int hlen;
+	u16 hlen;
 
 	switch (mode) {
 	case MLX5_INLINE_MODE_NONE:
@@ -139,19 +139,22 @@ static inline unsigned int mlx5e_calc_mi
 		hlen = eth_get_headlen(skb->data, skb_headlen(skb));
 		if (hlen == ETH_HLEN && !skb_vlan_tag_present(skb))
 			hlen += VLAN_HLEN;
-		return hlen;
+		break;
 	case MLX5_INLINE_MODE_IP:
 		/* When transport header is set to zero, it means no transport
 		 * header. When transport header is set to 0xff's, it means
 		 * transport header wasn't set.
 		 */
-		if (skb_transport_offset(skb))
-			return mlx5e_skb_l3_header_offset(skb);
+		if (skb_transport_offset(skb)) {
+			hlen = mlx5e_skb_l3_header_offset(skb);
+			break;
+		}
 		/* fall through */
 	case MLX5_INLINE_MODE_L2:
 	default:
-		return mlx5e_skb_l2_header_offset(skb);
+		hlen = mlx5e_skb_l2_header_offset(skb);
 	}
+	return min_t(u16, hlen, skb->len);
 }
 
 static inline void mlx5e_tx_skb_pull_inline(unsigned char **skb_data,