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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, Yishai Hadas <yishaih@mellanox.com>,
        Alex Vainman <alexv@mellanox.com>,
        Leon Romanovsky <leonro@mellanox.com>,
        Jason Gunthorpe <jgg@mellanox.com>
Subject: [PATCH 4.19 66/74] IB/mlx5: Fix RSS Toeplitz setup to be aligned with the HW specification
Date:   Mon,  5 Aug 2019 15:03:19 +0200
Message-Id: <20190805124941.149612455@linuxfoundation.org>
In-Reply-To: <20190805124935.819068648@linuxfoundation.org>
References: <20190805124935.819068648@linuxfoundation.org>
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From: Yishai Hadas <yishaih@mellanox.com>

commit b7165bd0d6cbb93732559be6ea8774653b204480 upstream.

The specification for the Toeplitz function doesn't require to set the key
explicitly to be symmetric. In case a symmetric functionality is required
a symmetric key can be simply used.

Wrongly forcing the algorithm to symmetric causes the wrong packet
distribution and a performance degradation.

Link: https://lore.kernel.org/r/20190723065733.4899-7-leon@kernel.org
Cc: <stable@vger.kernel.org> # 4.7
Fixes: 28d6137008b2 ("IB/mlx5: Add RSS QP support")
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Reviewed-by: Alex Vainman <alexv@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/infiniband/hw/mlx5/qp.c |    1 -
 1 file changed, 1 deletion(-)

--- a/drivers/infiniband/hw/mlx5/qp.c
+++ b/drivers/infiniband/hw/mlx5/qp.c
@@ -1501,7 +1501,6 @@ static int create_rss_raw_qp_tir(struct
 		}
 
 		MLX5_SET(tirc, tirc, rx_hash_fn, MLX5_RX_HASH_FN_TOEPLITZ);
-		MLX5_SET(tirc, tirc, rx_hash_symmetric, 1);
 		memcpy(rss_key, ucmd.rx_hash_key, len);
 		break;
 	}