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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Saeed Mahameed <saeedm@mellanox.com>
Subject: [PATCH 5.1 40/62] net/mlx5e: Rx, Fix checksum calculation for new hardware
Date:   Fri, 26 Jul 2019 17:24:52 +0200
Message-Id: <20190726152306.179800031@linuxfoundation.org>
In-Reply-To: <20190726152301.720139286@linuxfoundation.org>
References: <20190726152301.720139286@linuxfoundation.org>
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From: Saeed Mahameed <saeedm@mellanox.com>

[ Upstream commit db849faa9bef993a1379dc510623f750a72fa7ce ]

CQE checksum full mode in new HW, provides a full checksum of rx frame.
Covering bytes starting from eth protocol up to last byte in the received
frame (frame_size - ETH_HLEN), as expected by the stack.

Fixing up skb->csum by the driver is not required in such case. This fix
is to avoid wrong checksum calculation in drivers which already support
the new hardware with the new checksum mode.

Fixes: 85327a9c4150 ("net/mlx5: Update the list of the PCI supported devices")
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/mellanox/mlx5/core/en.h      |    1 +
 drivers/net/ethernet/mellanox/mlx5/core/en_main.c |    3 +++
 drivers/net/ethernet/mellanox/mlx5/core/en_rx.c   |    7 ++++++-
 include/linux/mlx5/mlx5_ifc.h                     |    3 ++-
 4 files changed, 12 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/en.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h
@@ -294,6 +294,7 @@ enum {
 	MLX5E_RQ_STATE_ENABLED,
 	MLX5E_RQ_STATE_AM,
 	MLX5E_RQ_STATE_NO_CSUM_COMPLETE,
+	MLX5E_RQ_STATE_CSUM_FULL, /* cqe_csum_full hw bit is set */
 };
 
 struct mlx5e_cq {
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -948,6 +948,9 @@ static int mlx5e_open_rq(struct mlx5e_ch
 	if (err)
 		goto err_destroy_rq;
 
+	if (MLX5_CAP_ETH(c->mdev, cqe_checksum_full))
+		__set_bit(MLX5E_RQ_STATE_CSUM_FULL, &c->rq.state);
+
 	if (params->rx_dim_enabled)
 		__set_bit(MLX5E_RQ_STATE_AM, &c->rq.state);
 
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
@@ -829,8 +829,14 @@ static inline void mlx5e_handle_csum(str
 		if (unlikely(get_ip_proto(skb, network_depth, proto) == IPPROTO_SCTP))
 			goto csum_unnecessary;
 
+		stats->csum_complete++;
 		skb->ip_summed = CHECKSUM_COMPLETE;
 		skb->csum = csum_unfold((__force __sum16)cqe->check_sum);
+
+		if (test_bit(MLX5E_RQ_STATE_CSUM_FULL, &rq->state))
+			return; /* CQE csum covers all received bytes */
+
+		/* csum might need some fixups ...*/
 		if (network_depth > ETH_HLEN)
 			/* CQE csum is calculated from the IP header and does
 			 * not cover VLAN headers (if present). This will add
@@ -841,7 +847,6 @@ static inline void mlx5e_handle_csum(str
 						 skb->csum);
 
 		mlx5e_skb_padding_csum(skb, network_depth, proto, stats);
-		stats->csum_complete++;
 		return;
 	}
 
--- a/include/linux/mlx5/mlx5_ifc.h
+++ b/include/linux/mlx5/mlx5_ifc.h
@@ -716,7 +716,8 @@ struct mlx5_ifc_per_protocol_networking_
 	u8         swp[0x1];
 	u8         swp_csum[0x1];
 	u8         swp_lso[0x1];
-	u8         reserved_at_23[0xd];
+	u8         cqe_checksum_full[0x1];
+	u8         reserved_at_24[0xc];
 	u8         max_vxlan_udp_ports[0x8];
 	u8         reserved_at_38[0x6];
 	u8         max_geneve_opt_len[0x1];