From 207628d844e94af4d0434b470dd0ecac0d412c78 Mon Sep 17 00:00:00 2001
From: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Date: Fri, 31 Aug 2018 14:29:16 +0300
Subject: [PATCH] net/mlx5e: Switch to Toeplitz RSS hash by default
Git-commit: 7ee2ace9c544a0886e02b54b625e521df8692d20
References: git-fixes
Patch-mainline: v5.1-rc6

Although XOR hash function can perform very well on some special use
cases, to align with all drivers, mlx5 driver should use Toeplitz hash
by default.
Toeplitz is more stable for the general use case and it is more standard
and reliable.

On top of that, since XOR (MLX5_RX_HASH_FN_INVERTED_XOR8) gives only a
repeated 8 bits pattern. When used for udp tunneling RSS source port
manipulation it results in fixed source port, which will cause bad RSS
spread.

Fixes: 2be6967cdbc9 ("net/mlx5e: Support ETH_RSS_HASH_XOR")
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reviewed-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Moshe Shemesh <moshe@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Denis Kirjanov <denis.kirjanov@suse.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index 6a2fd035d943..ed862fa63c57 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -4558,7 +4558,7 @@ void mlx5e_build_rq_params(struct mlx5_core_dev *mdev,
 
 void mlx5e_build_rss_params(struct mlx5e_params *params)
 {
-	params->rss_hfunc = ETH_RSS_HASH_XOR;
+	params->rss_hfunc = ETH_RSS_HASH_TOP;
 	netdev_rss_key_fill(params->toeplitz_hash_key, sizeof(params->toeplitz_hash_key));
 	mlx5e_build_default_indir_rqt(params->indirection_rqt,
 				      MLX5E_INDIR_RQT_SIZE, params->num_channels);
-- 
2.16.4