[PATCH net-next v4 16/33] mlx4: add XDP frame size and adjust max XDP MTU

[Jesper Dangaard Brouer]

The mlx4 drivers size of memory backing the RX packet is stored in
frag_stride. For XDP mode this will be PAGE_SIZE (normally 4096).
For normal mode frag_stride is 2048.

Also adjust MLX4_EN_MAX_XDP_MTU to take tailroom into account.

Cc: Tariq Toukan <tar...@mellanox.com>
Cc: Saeed Mahameed <sae...@mellanox.com>
Signed-off-by: Jesper Dangaard Brouer <bro...@redhat.com>
Reviewed-by: Tariq Toukan <tar...@mellanox.com>
---
 drivers/net/ethernet/mellanox/mlx4/en_netdev.c |    3 ++-
 drivers/net/ethernet/mellanox/mlx4/en_rx.c     |    1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c 
b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
index 43dcbd8214c6..5bd3cd37d50f 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
@@ -51,7 +51,8 @@
 #include "en_port.h"
 
 #define MLX4_EN_MAX_XDP_MTU ((int)(PAGE_SIZE - ETH_HLEN - (2 * VLAN_HLEN) - \
-                                  XDP_PACKET_HEADROOM))
+                               XDP_PACKET_HEADROOM -                       \
+                               SKB_DATA_ALIGN(sizeof(struct skb_shared_info))))
 
 int mlx4_en_setup_tc(struct net_device *dev, u8 up)
 {
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c 
b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
index 787139219813..8a10285b0e10 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
@@ -683,6 +683,7 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct 
mlx4_en_cq *cq, int bud
        rcu_read_lock();
        xdp_prog = rcu_dereference(ring->xdp_prog);
        xdp.rxq = &ring->xdp_rxq;
+       xdp.frame_sz = priv->frag_info[0].frag_stride;
        doorbell_pending = 0;
 
        /* We assume a 1:1 mapping between CQEs and Rx descriptors, so Rx