ethtool: Support for configurable RSS hash function

This patch extends the set/get_rxfh ethtool-options for getting or
setting the RSS hash function.

It modifies drivers implementation of set/get_rxfh accordingly.

This change also delegates the responsibility of checking whether a
modification to a certain RX flow hash parameter is supported to the
driver implementation of set_rxfh.

User-kernel API is done through the new hfunc bitmask field in the
ethtool_rxfh struct. A bit set in the hfunc field is corresponding to an
index in the new string-set ETH_SS_RSS_HASH_FUNCS.

Got approval from most of the relevant driver maintainers that their
driver is using Toeplitz, and for the few that didn't answered, also
assumed it is Toeplitz.

Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Ariel Elior <ariel.elior@qlogic.com>
Cc: Prashant Sreedharan <prashant@broadcom.com>
Cc: Michael Chan <mchan@broadcom.com>
Cc: Hariprasad S <hariprasad@chelsio.com>
Cc: Sathya Perla <sathya.perla@emulex.com>
Cc: Subbu Seetharaman <subbu.seetharaman@emulex.com>
Cc: Ajit Khaparde <ajit.khaparde@emulex.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
Cc: Bruce Allan <bruce.w.allan@intel.com>
Cc: Carolyn Wyborny <carolyn.wyborny@intel.com>
Cc: Don Skidmore <donald.c.skidmore@intel.com>
Cc: Greg Rose <gregory.v.rose@intel.com>
Cc: Matthew Vick <matthew.vick@intel.com>
Cc: John Ronciak <john.ronciak@intel.com>
Cc: Mitch Williams <mitch.a.williams@intel.com>
Cc: Amir Vadai <amirv@mellanox.com>
Cc: Solarflare linux maintainers <linux-net-drivers@solarflare.com>
Cc: Shradha Shah <sshah@solarflare.com>
Cc: Shreyas Bhatewara <sbhatewara@vmware.com>
Cc: "VMware, Inc." <pv-drivers@vmware.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Eyal Perry <eyalpe@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 39 insertions, 6 deletions

diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_ethtool.c b/drivers/net/ethernet/intel/fm10k/fm10k_ethtool.c
index 2d04464e6aa3..651f53bc7376 100644
--- a/drivers/net/ethernet/intel/fm10k/fm10k_ethtool.c
+++ b/drivers/net/ethernet/intel/fm10k/fm10k_ethtool.c
@@ -916,11 +916,15 @@ static u32 fm10k_get_rssrk_size(struct net_device *netdev)
 	return FM10K_RSSRK_SIZE * FM10K_RSSRK_ENTRIES_PER_REG;
 }
 
-static int fm10k_get_rssh(struct net_device *netdev, u32 *indir, u8 *key)
+static int fm10k_get_rssh(struct net_device *netdev, u32 *indir, u8 *key,
+			  u8 *hfunc)
 {
 	struct fm10k_intfc *interface = netdev_priv(netdev);
 	int i, err;
 
+	if (hfunc)
+		*hfunc = ETH_RSS_HASH_TOP;
+
 	err = fm10k_get_reta(netdev, indir);
 	if (err || !key)
 		return err;
@@ -932,12 +936,16 @@ static int fm10k_get_rssh(struct net_device *netdev, u32 *indir, u8 *key)
 }
 
 static int fm10k_set_rssh(struct net_device *netdev, const u32 *indir,
-			  const u8 *key)
+			  const u8 *key, const u8 hfunc)
 {
 	struct fm10k_intfc *interface = netdev_priv(netdev);
 	struct fm10k_hw *hw = &interface->hw;
 	int i, err;
 
+	/* We do not allow change in unsupported parameters */
+	if (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP)
+		return -EOPNOTSUPP;
+
 	err = fm10k_set_reta(netdev, indir);
 	if (err || !key)
 		return err;
diff --git a/drivers/net/ethernet/intel/i40evf/i40evf_ethtool.c b/drivers/net/ethernet/intel/i40evf/i40evf_ethtool.c
index 69a269b23be6..69b97bac182c 100644
--- a/drivers/net/ethernet/intel/i40evf/i40evf_ethtool.c
+++ b/drivers/net/ethernet/intel/i40evf/i40evf_ethtool.c
@@ -627,13 +627,19 @@ static u32 i40evf_get_rxfh_indir_size(struct net_device *netdev)
  *
  * Reads the indirection table directly from the hardware. Always returns 0.
  **/
-static int i40evf_get_rxfh(struct net_device *netdev, u32 *indir, u8 *key)
+static int i40evf_get_rxfh(struct net_device *netdev, u32 *indir, u8 *key,
+			   u8 *hfunc)
 {
 	struct i40evf_adapter *adapter = netdev_priv(netdev);
 	struct i40e_hw *hw = &adapter->hw;
 	u32 hlut_val;
 	int i, j;
 
+	if (hfunc)
+		*hfunc = ETH_RSS_HASH_TOP;
+	if (!indir)
+		return 0;
+
 	for (i = 0, j = 0; i <= I40E_VFQF_HLUT_MAX_INDEX; i++) {
 		hlut_val = rd32(hw, I40E_VFQF_HLUT(i));
 		indir[j++] = hlut_val & 0xff;
@@ -654,13 +660,20 @@ static int i40evf_get_rxfh(struct net_device *netdev, u32 *indir, u8 *key)
  * returns 0 after programming the table.
  **/
 static int i40evf_set_rxfh(struct net_device *netdev, const u32 *indir,
-			   const u8 *key)
+			   const u8 *key, const u8 hfunc)
 {
 	struct i40evf_adapter *adapter = netdev_priv(netdev);
 	struct i40e_hw *hw = &adapter->hw;
 	u32 hlut_val;
 	int i, j;
 
+	/* We do not allow change in unsupported parameters */
+	if (key ||
+	    (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP))
+		return -EOPNOTSUPP;
+	if (!indir)
+		return 0;
+
 	for (i = 0, j = 0; i <= I40E_VFQF_HLUT_MAX_INDEX; i++) {
 		hlut_val = indir[j++];
 		hlut_val |= indir[j++] << 8;
diff --git a/drivers/net/ethernet/intel/igb/igb_ethtool.c b/drivers/net/ethernet/intel/igb/igb_ethtool.c
index 02cfd3b14762..d5673eb90c54 100644
--- a/drivers/net/ethernet/intel/igb/igb_ethtool.c
+++ b/drivers/net/ethernet/intel/igb/igb_ethtool.c
@@ -2842,11 +2842,16 @@ static u32 igb_get_rxfh_indir_size(struct net_device *netdev)
 	return IGB_RETA_SIZE;
 }
 
-static int igb_get_rxfh(struct net_device *netdev, u32 *indir, u8 *key)
+static int igb_get_rxfh(struct net_device *netdev, u32 *indir, u8 *key,
+			u8 *hfunc)
 {
 	struct igb_adapter *adapter = netdev_priv(netdev);
 	int i;
 
+	if (hfunc)
+		*hfunc = ETH_RSS_HASH_TOP;
+	if (!indir)
+		return 0;
 	for (i = 0; i < IGB_RETA_SIZE; i++)
 		indir[i] = adapter->rss_indir_tbl[i];
 
@@ -2889,13 +2894,20 @@ void igb_write_rss_indir_tbl(struct igb_adapter *adapter)
 }
 
 static int igb_set_rxfh(struct net_device *netdev, const u32 *indir,
-			const u8 *key)
+			const u8 *key, const u8 hfunc)
 {
 	struct igb_adapter *adapter = netdev_priv(netdev);
 	struct e1000_hw *hw = &adapter->hw;
 	int i;
 	u32 num_queues;
 
+	/* We do not allow change in unsupported parameters */
+	if (key ||
+	    (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP))
+		return -EOPNOTSUPP;
+	if (!indir)
+		return 0;
+
 	num_queues = adapter->rss_queues;
 
 	switch (hw->mac.type) {