From: Tariq Toukan <tariqt@nvidia.com>
To: Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Andrew Lunn <andrew+netdev@lunn.ch>,
"David S. Miller" <davem@davemloft.net>
Cc: Saeed Mahameed <saeedm@nvidia.com>,
Leon Romanovsky <leon@kernel.org>,
Tariq Toukan <tariqt@nvidia.com>, Mark Bloch <mbloch@nvidia.com>,
Nimrod Oren <noren@nvidia.com>, Yael Chemla <ychemla@nvidia.com>,
Carolina Jubran <cjubran@nvidia.com>,
Simon Horman <horms@kernel.org>, Gal Pressman <gal@nvidia.com>,
Kees Cook <kees@kernel.org>, Dragos Tatulea <dtatulea@nvidia.com>,
<netdev@vger.kernel.org>, <linux-rdma@vger.kernel.org>,
<linux-kernel@vger.kernel.org>
Subject: [PATCH net-next 1/5] net/mlx5e: remove channel count limit for XOR8 RSS hash
Date: Mon, 11 May 2026 20:27:15 +0300 [thread overview]
Message-ID: <20260511172719.330490-2-tariqt@nvidia.com> (raw)
In-Reply-To: <20260511172719.330490-1-tariqt@nvidia.com>
From: Yael Chemla <ychemla@nvidia.com>
mlx5e_ethtool_set_channels() and mlx5e_rxfh_hfunc_check() rejected
channel counts that would produce an indirection table larger than 256
entries when the XOR8 hash function was active. This check was
introduced in commit 49e6c9387051 ("net/mlx5e: RSS, Block XOR hash
with over 128 channels").
XOR8 yields an 8-bit hash, so in practice only up to 256 entries in the
indirection table can be reached due to limited entropy. However, this
does not provide a strong justification for prohibiting larger
indirection tables. Remove the limitation.
Signed-off-by: Yael Chemla <ychemla@nvidia.com>
Reviewed-by: Nimrod Oren <noren@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
---
.../net/ethernet/mellanox/mlx5/core/en/rqt.c | 7 ---
.../net/ethernet/mellanox/mlx5/core/en/rqt.h | 1 -
.../ethernet/mellanox/mlx5/core/en_ethtool.c | 48 -------------------
3 files changed, 56 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/rqt.c b/drivers/net/ethernet/mellanox/mlx5/core/en/rqt.c
index 8d9a3b5ec973..bcafb4bf9415 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/rqt.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/rqt.c
@@ -179,13 +179,6 @@ u32 mlx5e_rqt_size(struct mlx5_core_dev *mdev, unsigned int num_channels)
return min_t(u32, rqt_size, max_cap_rqt_size);
}
-#define MLX5E_MAX_RQT_SIZE_ALLOWED_WITH_XOR8_HASH 256
-
-unsigned int mlx5e_rqt_max_num_channels_allowed_for_xor8(void)
-{
- return MLX5E_MAX_RQT_SIZE_ALLOWED_WITH_XOR8_HASH / MLX5E_UNIFORM_SPREAD_RQT_FACTOR;
-}
-
void mlx5e_rqt_destroy(struct mlx5e_rqt *rqt)
{
mlx5_core_destroy_rqt(rqt->mdev, rqt->rqtn);
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/rqt.h b/drivers/net/ethernet/mellanox/mlx5/core/en/rqt.h
index 2f9e04a8418f..e0bc30308c77 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/rqt.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/rqt.h
@@ -38,7 +38,6 @@ static inline u32 mlx5e_rqt_get_rqtn(struct mlx5e_rqt *rqt)
}
u32 mlx5e_rqt_size(struct mlx5_core_dev *mdev, unsigned int num_channels);
-unsigned int mlx5e_rqt_max_num_channels_allowed_for_xor8(void);
int mlx5e_rqt_redirect_direct(struct mlx5e_rqt *rqt, u32 rqn, u32 *vhca_id);
int mlx5e_rqt_redirect_indir(struct mlx5e_rqt *rqt, u32 *rqns, u32 *vhca_ids,
unsigned int num_rqns,
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c b/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
index bb61e2179078..a6da0219723c 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
@@ -511,17 +511,6 @@ int mlx5e_ethtool_set_channels(struct mlx5e_priv *priv,
mutex_lock(&priv->state_lock);
- if (mlx5e_rx_res_get_current_hash(priv->rx_res).hfunc == ETH_RSS_HASH_XOR) {
- unsigned int xor8_max_channels = mlx5e_rqt_max_num_channels_allowed_for_xor8();
-
- if (count > xor8_max_channels) {
- err = -EINVAL;
- netdev_err(priv->netdev, "%s: Requested number of channels (%d) exceeds the maximum allowed by the XOR8 RSS hfunc (%d)\n",
- __func__, count, xor8_max_channels);
- goto out;
- }
- }
-
/* If RXFH is configured, changing the channels number is allowed only if
* it does not require resizing the RSS table. This is because the previous
* configuration may no longer be compatible with the new RSS table.
@@ -1501,29 +1490,6 @@ static int mlx5e_get_rxfh(struct net_device *netdev, struct ethtool_rxfh_param *
return 0;
}
-static int mlx5e_rxfh_hfunc_check(struct mlx5e_priv *priv,
- const struct ethtool_rxfh_param *rxfh,
- struct netlink_ext_ack *extack)
-{
- unsigned int count;
-
- count = priv->channels.params.num_channels;
-
- if (rxfh->hfunc == ETH_RSS_HASH_XOR) {
- unsigned int xor8_max_channels = mlx5e_rqt_max_num_channels_allowed_for_xor8();
-
- if (count > xor8_max_channels) {
- NL_SET_ERR_MSG_FMT_MOD(
- extack,
- "Number of channels (%u) exceeds the max for XOR8 RSS (%u)",
- count, xor8_max_channels);
- return -EINVAL;
- }
- }
-
- return 0;
-}
-
static int mlx5e_set_rxfh(struct net_device *dev,
struct ethtool_rxfh_param *rxfh,
struct netlink_ext_ack *extack)
@@ -1535,16 +1501,11 @@ static int mlx5e_set_rxfh(struct net_device *dev,
mutex_lock(&priv->state_lock);
- err = mlx5e_rxfh_hfunc_check(priv, rxfh, extack);
- if (err)
- goto unlock;
-
err = mlx5e_rx_res_rss_set_rxfh(priv->rx_res, rxfh->rss_context,
rxfh->indir, rxfh->key,
hfunc == ETH_RSS_HASH_NO_CHANGE ? NULL : &hfunc,
rxfh->input_xfrm == RXH_XFRM_NO_CHANGE ? NULL : &symmetric);
-unlock:
mutex_unlock(&priv->state_lock);
return err;
}
@@ -1561,10 +1522,6 @@ static int mlx5e_create_rxfh_context(struct net_device *dev,
mutex_lock(&priv->state_lock);
- err = mlx5e_rxfh_hfunc_check(priv, rxfh, extack);
- if (err)
- goto unlock;
-
err = mlx5e_rx_res_rss_init(priv->rx_res, rxfh->rss_context,
priv->channels.params.num_channels);
if (err)
@@ -1601,16 +1558,11 @@ static int mlx5e_modify_rxfh_context(struct net_device *dev,
mutex_lock(&priv->state_lock);
- err = mlx5e_rxfh_hfunc_check(priv, rxfh, extack);
- if (err)
- goto unlock;
-
err = mlx5e_rx_res_rss_set_rxfh(priv->rx_res, rxfh->rss_context,
rxfh->indir, rxfh->key,
hfunc == ETH_RSS_HASH_NO_CHANGE ? NULL : &hfunc,
rxfh->input_xfrm == RXH_XFRM_NO_CHANGE ? NULL : &symmetric);
-unlock:
mutex_unlock(&priv->state_lock);
return err;
}
--
2.44.0
next prev parent reply other threads:[~2026-05-11 17:28 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-11 17:27 [PATCH net-next 0/5] net/mlx5e: improve RSS indirection table sizing and resizing Tariq Toukan
2026-05-11 17:27 ` Tariq Toukan [this message]
2026-05-11 17:27 ` [PATCH net-next 2/5] net/mlx5e: advertise max RSS indirection table size to ethtool Tariq Toukan
2026-05-11 17:27 ` [PATCH net-next 3/5] net/mlx5e: resize non-default RSS indirection tables on channel change Tariq Toukan
2026-05-11 17:27 ` [PATCH net-next 4/5] net/mlx5e: resize configured default RSS context table " Tariq Toukan
2026-05-11 17:27 ` [PATCH net-next 5/5] net/mlx5e: increase RSS indirection table spread factor Tariq Toukan
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