svn commit: r359846 - stable/11/sys/dev/mlx5/mlx5_en

[Hans Petter Selasky]

Author: hselasky
Date: Mon Apr 13 08:28:02 2020
New Revision: 359846
URL: https://svnweb.freebsd.org/changeset/base/359846

Log:
  MFC r359654:
  Ensure a minimum inline size of 16 bytes in mlx5en(4).
  
  This includes 14 bytes of ethernet header and 2 bytes of VLAN header.
  
  This allows for making assumptions about the inline size limit
  in the fast transmit path later on.
  
  Use a signed integer variable to catch underflow.
  
  Sponsored by:	Mellanox Technologies

Modified:
  stable/11/sys/dev/mlx5/mlx5_en/mlx5_en_main.c
Directory Properties:
  stable/11/   (props changed)

Modified: stable/11/sys/dev/mlx5/mlx5_en/mlx5_en_main.c
==============================================================================
--- stable/11/sys/dev/mlx5/mlx5_en/mlx5_en_main.c	Mon Apr 13 08:27:19 2020	(r359845)
+++ stable/11/sys/dev/mlx5/mlx5_en/mlx5_en_main.c	Mon Apr 13 08:28:02 2020	(r359846)
@@ -3351,15 +3351,19 @@ mlx5e_check_required_hca_cap(struct mlx5_core_dev *mde
 static u16
 mlx5e_get_max_inline_cap(struct mlx5_core_dev *mdev)
 {
-	uint32_t bf_buf_size = (1U << MLX5_CAP_GEN(mdev, log_bf_reg_size)) / 2U;
+	const int min_size = ETHER_VLAN_ENCAP_LEN + ETHER_HDR_LEN;
+	const int max_size = MLX5E_MAX_TX_INLINE;
+	const int bf_buf_size =
+	    ((1U << MLX5_CAP_GEN(mdev, log_bf_reg_size)) / 2U) -
+	    (sizeof(struct mlx5e_tx_wqe) - 2);
 
-	bf_buf_size -= sizeof(struct mlx5e_tx_wqe) - 2;
-
-	/* verify against driver hardware limit */
-	if (bf_buf_size > MLX5E_MAX_TX_INLINE)
-		bf_buf_size = MLX5E_MAX_TX_INLINE;
-
-	return (bf_buf_size);
+	/* verify against driver limits */
+	if (bf_buf_size > max_size)
+		return (max_size);
+	else if (bf_buf_size < min_size)
+		return (min_size);
+	else
+		return (bf_buf_size);
 }
 
 static int