Patch "net/mlx5e: Modify TIRs hash only when it's needed" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

net/mlx5e: Modify TIRs hash only when it's needed

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
net-mlx5e-modify-tirs-hash-only-when-it-s-needed.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Gal Pressman <[email protected]>
Date: Wed, 11 Jan 2017 14:32:26 +0200
Subject: net/mlx5e: Modify TIRs hash only when it's needed

From: Gal Pressman <[email protected]>

commit 1d3398facd08a7fd4202f269317a95668eb880b9 upstream.

We don't need to modify our TIRs unless the user requested a change in the hash function/key, for example when changing indirection only.

Tested:
# Modify TIRs hash is needed
ethtool -X ethX hkey <new key>
ethtool -X ethX hfunc <new func>

# Modify TIRs hash is not needed
ethtool -X ethX equal <new indirection table>

All cases are verified with TCP Multi-Stream traffic over IPv4 & IPv6.

---
 drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c |   18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

@@ -991,6 +991,7 @@ static int mlx5e_set_rxfh(struct net_dev
 {
 	struct mlx5e_priv *priv = netdev_priv(dev);
 	int inlen = MLX5_ST_SZ_BYTES(modify_tir_in);
+	bool hash_changed = false;
 	void *in;
 
 	if ((hfunc != ETH_RSS_HASH_NO_CHANGE) &&

@@ -1012,14 +1013,21 @@ static int mlx5e_set_rxfh(struct net_dev
 		mlx5e_redirect_rqt(priv, rqtn, MLX5E_INDIR_RQT_SIZE, 0);
 	}
 
-	if (key)
+	if (hfunc != ETH_RSS_HASH_NO_CHANGE &&
+	    hfunc != priv->params.rss_hfunc) {
+		priv->params.rss_hfunc = hfunc;
+		hash_changed = true;
+	}
+
+	if (key) {
 		memcpy(priv->params.toeplitz_hash_key, key,
 		       sizeof(priv->params.toeplitz_hash_key));
+		hash_changed = hash_changed ||
+			       priv->params.rss_hfunc == ETH_RSS_HASH_TOP;
+	}
 
-	if (hfunc != ETH_RSS_HASH_NO_CHANGE)
-		priv->params.rss_hfunc = hfunc;
-
-	mlx5e_modify_tirs_hash(priv, in, inlen);
+	if (hash_changed)
+		mlx5e_modify_tirs_hash(priv, in, inlen);
 
 	mutex_unlock(&priv->state_lock);
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/net-mlx5e-modify-tirs-hash-only-when-it-s-needed.patch