diff mbox series

[net,V2,10/12] net/mlx5e: RSS, Block XOR hash with over 128 channels

Message ID 20240409190820.227554-11-tariqt@nvidia.com (mailing list archive)
State Accepted
Commit 49e6c9387051716169ff6a6c5ddd4d9f358db2e9
Delegated to: Netdev Maintainers
Headers show
Series mlx5 misc fixes | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 943 this patch: 943
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers fail 1 blamed authors not CCed: jacob.e.keller@intel.com; 2 maintainers not CCed: linux-rdma@vger.kernel.org jacob.e.keller@intel.com
netdev/build_clang success Errors and warnings before: 953 this patch: 953
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 954 this patch: 954
netdev/checkpatch warning WARNING: line length of 84 exceeds 80 columns WARNING: line length of 91 exceeds 80 columns WARNING: line length of 95 exceeds 80 columns
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-04-10--06-00 (tests: 962)

Commit Message

Tariq Toukan April 9, 2024, 7:08 p.m. UTC 
From: Carolina Jubran <cjubran@nvidia.com>

When supporting more than 128 channels, the RQT size is
calculated by multiplying the number of channels by 2
and rounding up to the nearest power of 2.

The index of the RQT is derived from the RSS hash
calculations. If XOR8 is used as the RSS hash function,
there are only 256 possible hash results, and therefore,
only 256 indexes can be reached in the RQT.

Block setting the RSS hash function to XOR when the number
of channels exceeds 128.

Fixes: 74a8dadac17e ("net/mlx5e: Preparations for supporting larger number of channels")
Signed-off-by: Carolina Jubran <cjubran@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  | 28 +++++++++++++++++--
 3 files changed, 34 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/rqt.c b/drivers/net/ethernet/mellanox/mlx5/core/en/rqt.c
index bcafb4bf9415..8d9a3b5ec973 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/rqt.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/rqt.c
@@ -179,6 +179,13 @@  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 e0bc30308c77..2f9e04a8418f 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/rqt.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/rqt.h
@@ -38,6 +38,7 @@  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 93461b0c5703..8f101181648c 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
@@ -451,6 +451,17 @@  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.
@@ -1298,17 +1309,30 @@  int mlx5e_set_rxfh(struct net_device *dev, struct ethtool_rxfh_param *rxfh,
 	struct mlx5e_priv *priv = netdev_priv(dev);
 	u32 *rss_context = &rxfh->rss_context;
 	u8 hfunc = rxfh->hfunc;
+	unsigned int count;
 	int err;
 
 	mutex_lock(&priv->state_lock);
+
+	count = priv->channels.params.num_channels;
+
+	if (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: Cannot set RSS hash function to XOR, current number of channels (%d) exceeds the maximum allowed for XOR8 RSS hfunc (%d)\n",
+				   __func__, count, xor8_max_channels);
+			goto unlock;
+		}
+	}
+
 	if (*rss_context && rxfh->rss_delete) {
 		err = mlx5e_rx_res_rss_destroy(priv->rx_res, *rss_context);
 		goto unlock;
 	}
 
 	if (*rss_context == ETH_RXFH_CONTEXT_ALLOC) {
-		unsigned int count = priv->channels.params.num_channels;
-
 		err = mlx5e_rx_res_rss_init(priv->rx_res, rss_context, count);
 		if (err)
 			goto unlock;