[PATCH 4.19 66/74] IB/mlx5: Fix RSS Toeplitz setup to be aligned with the HW specification

From: Greg Kroah-Hartman
Date: Mon Aug 05 2019 - 09:19:20 EST

From: Yishai Hadas <yishaih@xxxxxxxxxxxx>

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@xxxxxxxxxx
Cc: <stable@xxxxxxxxxxxxxxx> # 4.7
Fixes: 28d6137008b2 ("IB/mlx5: Add RSS QP support")
Signed-off-by: Yishai Hadas <yishaih@xxxxxxxxxxxx>
Reviewed-by: Alex Vainman <alexv@xxxxxxxxxxxx>
Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

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);