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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, Maxim Mikityanskiy <maximmi@nvidia.com>,
        Tariq Toukan <tariqt@nvidia.com>,
        Saeed Mahameed <saeedm@nvidia.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 28/44] net/mlx5e: Properly block LRO when XDP is enabled
Date:   Mon, 23 May 2022 19:05:12 +0200
Message-Id: <20220523165758.240884429@linuxfoundation.org>
In-Reply-To: <20220523165752.797318097@linuxfoundation.org>
References: <20220523165752.797318097@linuxfoundation.org>
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From: Maxim Mikityanskiy <maximmi@nvidia.com>

[ Upstream commit cf6e34c8c22fba66bd21244b95ea47e235f68974 ]

LRO is incompatible and mutually exclusive with XDP. However, the needed
checks are only made when enabling XDP. If LRO is enabled when XDP is
already active, the command will succeed, and XDP will be skipped in the
data path, although still enabled.

This commit fixes the bug by checking the XDP status in
mlx5e_fix_features and disabling LRO if XDP is enabled.

Fixes: 86994156c736 ("net/mlx5e: XDP fast RX drop bpf programs support")
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index 5979fcf124bb..75872aef44d0 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -3739,6 +3739,13 @@ static netdev_features_t mlx5e_fix_features(struct net_device *netdev,
 			netdev_warn(netdev, "Disabling LRO, not supported in legacy RQ\n");
 	}
 
+	if (params->xdp_prog) {
+		if (features & NETIF_F_LRO) {
+			netdev_warn(netdev, "LRO is incompatible with XDP\n");
+			features &= ~NETIF_F_LRO;
+		}
+	}
+
 	if (MLX5E_GET_PFLAG(params, MLX5E_PFLAG_RX_CQE_COMPRESS)) {
 		features &= ~NETIF_F_RXHASH;
 		if (netdev->features & NETIF_F_RXHASH)
-- 
2.35.1