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: NEyal Perry <eyalpe@mellanox.com>
Signed-off-by: NAmir Vadai <amirv@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/amd/xgbe/xgbe-ethtool.c

@@ -511,7 +511,8 @@ static u32 xgbe_get_rxfh_indir_size(struct net_device *netdev)
 	return ARRAY_SIZE(pdata->rss_table);
 }
 
-static int xgbe_get_rxfh(struct net_device *netdev, u32 *indir, u8 *key)
+static int xgbe_get_rxfh(struct net_device *netdev, u32 *indir, u8 *key,
+			 u8 *hfunc)
 {
 	struct xgbe_prv_data *pdata = netdev_priv(netdev);
 	unsigned int i;
@@ -525,16 +526,22 @@ static int xgbe_get_rxfh(struct net_device *netdev, u32 *indir, u8 *key)
 	if (key)
 		memcpy(key, pdata->rss_key, sizeof(pdata->rss_key));
 
+	if (hfunc)
+		*hfunc = ETH_RSS_HASH_TOP;
+
 	return 0;
 }
 
 static int xgbe_set_rxfh(struct net_device *netdev, const u32 *indir,
-			 const u8 *key)
+			 const u8 *key, const u8 hfunc)
 {
 	struct xgbe_prv_data *pdata = netdev_priv(netdev);
 	struct xgbe_hw_if *hw_if = &pdata->hw_if;
 	unsigned int ret;
 
+	if (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP)
+		return -EOPNOTSUPP;
+
 	if (indir) {
 		ret = hw_if->set_rss_lookup_table(pdata, indir);
 		if (ret)

drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c

@@ -3358,12 +3358,18 @@ static u32 bnx2x_get_rxfh_indir_size(struct net_device *dev)
 	return T_ETH_INDIRECTION_TABLE_SIZE;
 }
 
-static int bnx2x_get_rxfh(struct net_device *dev, u32 *indir, u8 *key)
+static int bnx2x_get_rxfh(struct net_device *dev, u32 *indir, u8 *key,
+			  u8 *hfunc)
 {
 	struct bnx2x *bp = netdev_priv(dev);
 	u8 ind_table[T_ETH_INDIRECTION_TABLE_SIZE] = {0};
 	size_t i;
 
+	if (hfunc)
+		*hfunc = ETH_RSS_HASH_TOP;
+	if (!indir)
+		return 0;
+
 	/* Get the current configuration of the RSS indirection table */
 	bnx2x_get_rss_ind_table(&bp->rss_conf_obj, ind_table);
 
@@ -3383,11 +3389,21 @@ static int bnx2x_get_rxfh(struct net_device *dev, u32 *indir, u8 *key)
 }
 
 static int bnx2x_set_rxfh(struct net_device *dev, const u32 *indir,
-			  const u8 *key)
+			  const u8 *key, const u8 hfunc)
 {
 	struct bnx2x *bp = netdev_priv(dev);
 	size_t i;
 
+	/* We require at least one supported parameter to be changed and no
+	 * change in any of the unsupported parameters
+	 */
+	if (key ||
+	    (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP))
+		return -EOPNOTSUPP;
+
+	if (!indir)
+		return 0;
+
 	for (i = 0; i < T_ETH_INDIRECTION_TABLE_SIZE; i++) {
 		/*
 		 * The same as in bnx2x_get_rxfh: we can't use a memcpy()

drivers/net/ethernet/broadcom/tg3.c

@@ -12561,22 +12561,38 @@ static u32 tg3_get_rxfh_indir_size(struct net_device *dev)
 	return size;
 }
 
-static int tg3_get_rxfh(struct net_device *dev, u32 *indir, u8 *key)
+static int tg3_get_rxfh(struct net_device *dev, u32 *indir, u8 *key, u8 *hfunc)
 {
 	struct tg3 *tp = netdev_priv(dev);
 	int i;
 
+	if (hfunc)
+		*hfunc = ETH_RSS_HASH_TOP;
+	if (!indir)
+		return 0;
+
 	for (i = 0; i < TG3_RSS_INDIR_TBL_SIZE; i++)
 		indir[i] = tp->rss_ind_tbl[i];
 
 	return 0;
 }
 
-static int tg3_set_rxfh(struct net_device *dev, const u32 *indir, const u8 *key)
+static int tg3_set_rxfh(struct net_device *dev, const u32 *indir, const u8 *key,
+			const u8 hfunc)
 {
 	struct tg3 *tp = netdev_priv(dev);
 	size_t i;
 
+	/* We require at least one supported parameter to be changed and no
+	 * change in any of the unsupported parameters
+	 */
+	if (key ||
+	    (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP))
+		return -EOPNOTSUPP;
+
+	if (!indir)
+		return 0;
+
 	for (i = 0; i < TG3_RSS_INDIR_TBL_SIZE; i++)
 		tp->rss_ind_tbl[i] = indir[i];
 

drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c

@@ -2923,21 +2923,35 @@ static u32 get_rss_table_size(struct net_device *dev)
 	return pi->rss_size;
 }
 
-static int get_rss_table(struct net_device *dev, u32 *p, u8 *key)
+static int get_rss_table(struct net_device *dev, u32 *p, u8 *key, u8 *hfunc)
 {
 	const struct port_info *pi = netdev_priv(dev);
 	unsigned int n = pi->rss_size;
 
+	if (hfunc)
+		*hfunc = ETH_RSS_HASH_TOP;
+	if (!p)
+		return 0;
 	while (n--)
 		p[n] = pi->rss[n];
 	return 0;
 }
 
-static int set_rss_table(struct net_device *dev, const u32 *p, const u8 *key)
+static int set_rss_table(struct net_device *dev, const u32 *p, const u8 *key,
+			 const u8 hfunc)
 {
 	unsigned int i;
 	struct port_info *pi = netdev_priv(dev);
 
+	/* We require at least one supported parameter to be changed and no
+	 * change in any of the unsupported parameters
+	 */
+	if (key ||
+	    (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP))
+		return -EOPNOTSUPP;
+	if (!p)
+		return 0;
+
 	for (i = 0; i < pi->rss_size; i++)
 		pi->rss[i] = p[i];
 	if (pi->adapter->flags & FULL_INIT_DONE)

drivers/net/ethernet/emulex/benet/be_ethtool.c

@@ -1171,7 +1171,8 @@ static u32 be_get_rxfh_key_size(struct net_device *netdev)
 	return RSS_HASH_KEY_LEN;
 }
 
-static int be_get_rxfh(struct net_device *netdev, u32 *indir, u8 *hkey)
+static int be_get_rxfh(struct net_device *netdev, u32 *indir, u8 *hkey,
+		       u8 *hfunc)
 {
 	struct be_adapter *adapter = netdev_priv(netdev);
 	int i;
@@ -1185,16 +1186,23 @@ static int be_get_rxfh(struct net_device *netdev, u32 *indir, u8 *hkey)
 	if (hkey)
 		memcpy(hkey, rss->rss_hkey, RSS_HASH_KEY_LEN);
 
+	if (hfunc)
+		*hfunc = ETH_RSS_HASH_TOP;
+
 	return 0;
 }
 
 static int be_set_rxfh(struct net_device *netdev, const u32 *indir,
-		       const u8 *hkey)
+		       const u8 *hkey, const u8 hfunc)
 {
 	int rc = 0, i, j;
 	struct be_adapter *adapter = netdev_priv(netdev);
 	u8 rsstable[RSS_INDIR_TABLE_LEN];
 
+	/* We do not allow change in unsupported parameters */
+	if (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP)
+		return -EOPNOTSUPP;
+
 	if (indir) {
 		struct be_rx_obj *rxo;
 

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;

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;

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) {

drivers/net/ethernet/mellanox/mlx4/en_ethtool.c

@@ -978,7 +978,8 @@ static u32 mlx4_en_get_rxfh_key_size(struct net_device *netdev)
 	return MLX4_EN_RSS_KEY_SIZE;
 }
 
-static int mlx4_en_get_rxfh(struct net_device *dev, u32 *ring_index, u8 *key)
+static int mlx4_en_get_rxfh(struct net_device *dev, u32 *ring_index, u8 *key,
+			    u8 *hfunc)
 {
 	struct mlx4_en_priv *priv = netdev_priv(dev);
 	struct mlx4_en_rss_map *rss_map = &priv->rss_map;
@@ -990,16 +991,20 @@ static int mlx4_en_get_rxfh(struct net_device *dev, u32 *ring_index, u8 *key)
 	rss_rings = 1 << ilog2(rss_rings);
 
 	while (n--) {
+		if (!ring_index)
+			break;
 		ring_index[n] = rss_map->qps[n % rss_rings].qpn -
 			rss_map->base_qpn;
 	}
 	if (key)
 		memcpy(key, priv->rss_key, MLX4_EN_RSS_KEY_SIZE);
+	if (hfunc)
+		*hfunc = ETH_RSS_HASH_TOP;
 	return err;
 }
 
 static int mlx4_en_set_rxfh(struct net_device *dev, const u32 *ring_index,
-			    const u8 *key)
+			    const u8 *key, const u8 hfunc)
 {
 	struct mlx4_en_priv *priv = netdev_priv(dev);
 	struct mlx4_en_dev *mdev = priv->mdev;
@@ -1008,6 +1013,10 @@ static int mlx4_en_set_rxfh(struct net_device *dev, const u32 *ring_index,
 	int i;
 	int rss_rings = 0;
 
+	/* We do not allow change in unsupported parameters */
+	if (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP)
+		return -EOPNOTSUPP;
+
 	/* Calculate RSS table size and make sure flows are spread evenly
 	 * between rings
 	 */

drivers/net/ethernet/sfc/ethtool.c

@@ -1086,19 +1086,29 @@ static u32 efx_ethtool_get_rxfh_indir_size(struct net_device *net_dev)
 		0 : ARRAY_SIZE(efx->rx_indir_table));
 }
 
-static int efx_ethtool_get_rxfh(struct net_device *net_dev, u32 *indir, u8 *key)
+static int efx_ethtool_get_rxfh(struct net_device *net_dev, u32 *indir, u8 *key,
+				u8 *hfunc)
 {
 	struct efx_nic *efx = netdev_priv(net_dev);
 
-	memcpy(indir, efx->rx_indir_table, sizeof(efx->rx_indir_table));
+	if (hfunc)
+		*hfunc = ETH_RSS_HASH_TOP;
+	if (indir)
+		memcpy(indir, efx->rx_indir_table, sizeof(efx->rx_indir_table));
 	return 0;
 }
 
-static int efx_ethtool_set_rxfh(struct net_device *net_dev,
-				const u32 *indir, const u8 *key)
+static int efx_ethtool_set_rxfh(struct net_device *net_dev, const u32 *indir,
+				const u8 *key, const u8 hfunc)
 {
 	struct efx_nic *efx = netdev_priv(net_dev);
 
+	/* 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;
 	memcpy(efx->rx_indir_table, indir, sizeof(efx->rx_indir_table));
 	efx->type->rx_push_rss_config(efx);
 	return 0;

drivers/net/vmxnet3/vmxnet3_ethtool.c

@@ -583,12 +583,16 @@ vmxnet3_get_rss_indir_size(struct net_device *netdev)
 }
 
 static int
-vmxnet3_get_rss(struct net_device *netdev, u32 *p, u8 *key)
+vmxnet3_get_rss(struct net_device *netdev, u32 *p, u8 *key, u8 *hfunc)
 {
 	struct vmxnet3_adapter *adapter = netdev_priv(netdev);
 	struct UPT1_RSSConf *rssConf = adapter->rss_conf;
 	unsigned int n = rssConf->indTableSize;
 
+	if (hfunc)
+		*hfunc = ETH_RSS_HASH_TOP;
+	if (!p)
+		return 0;
 	while (n--)
 		p[n] = rssConf->indTable[n];
 	return 0;
@@ -596,13 +600,20 @@ vmxnet3_get_rss(struct net_device *netdev, u32 *p, u8 *key)
 }
 
 static int
-vmxnet3_set_rss(struct net_device *netdev, const u32 *p, const u8 *key)
+vmxnet3_set_rss(struct net_device *netdev, const u32 *p, const u8 *key,
+		const u8 hfunc)
 {
 	unsigned int i;
 	unsigned long flags;
 	struct vmxnet3_adapter *adapter = netdev_priv(netdev);
 	struct UPT1_RSSConf *rssConf = adapter->rss_conf;
 
+	/* We do not allow change in unsupported parameters */
+	if (key ||
+	    (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP))
+		return -EOPNOTSUPP;
+	if (!p)
+		return 0;
 	for (i = 0; i < rssConf->indTableSize; i++)
 		rssConf->indTable[i] = p[i];
 

include/linux/ethtool.h

@@ -59,6 +59,26 @@ enum ethtool_phys_id_state {
 	ETHTOOL_ID_OFF
 };
 
+enum {
+	ETH_RSS_HASH_TOP_BIT, /* Configurable RSS hash function - Toeplitz */
+	ETH_RSS_HASH_XOR_BIT, /* Configurable RSS hash function - Xor */
+
+	/*
+	 * Add your fresh new hash function bits above and remember to update
+	 * rss_hash_func_strings[] in ethtool.c
+	 */
+	ETH_RSS_HASH_FUNCS_COUNT
+};
+
+#define __ETH_RSS_HASH_BIT(bit)	((u32)1 << (bit))
+#define __ETH_RSS_HASH(name)	__ETH_RSS_HASH_BIT(ETH_RSS_HASH_##name##_BIT)
+
+#define ETH_RSS_HASH_TOP	__ETH_RSS_HASH(TOP)
+#define ETH_RSS_HASH_XOR	__ETH_RSS_HASH(XOR)
+
+#define ETH_RSS_HASH_UNKNOWN	0
+#define ETH_RSS_HASH_NO_CHANGE	0
+
 struct net_device;
 
 /* Some generic methods drivers may use in their ethtool_ops */
@@ -158,17 +178,14 @@ static inline u32 ethtool_rxfh_indir_default(u32 index, u32 n_rx_rings)
  *	Returns zero if not supported for this specific device.
  * @get_rxfh_indir_size: Get the size of the RX flow hash indirection table.
  *	Returns zero if not supported for this specific device.
- * @get_rxfh: Get the contents of the RX flow hash indirection table and hash
- *	key.
- *	Will only be called if one or both of @get_rxfh_indir_size and
- *	@get_rxfh_key_size are implemented and return non-zero.
- *	Returns a negative error code or zero.
- * @set_rxfh: Set the contents of the RX flow hash indirection table and/or
- *	hash key.  In case only the indirection table or hash key is to be
- *	changed, the other argument will be %NULL.
- *	Will only be called if one or both of @get_rxfh_indir_size and
- *	@get_rxfh_key_size are implemented and return non-zero.
+ * @get_rxfh: Get the contents of the RX flow hash indirection table, hash key
+ *	and/or hash function.
  *	Returns a negative error code or zero.
+ * @set_rxfh: Set the contents of the RX flow hash indirection table, hash
+ *	key, and/or hash function.  Arguments which are set to %NULL or zero
+ *	will remain unchanged.
+ *	Returns a negative error code or zero. An error code must be returned
+ *	if at least one unsupported change was requested.
  * @get_channels: Get number of channels.
  * @set_channels: Set number of channels.  Returns a negative error code or
  *	zero.
@@ -241,9 +258,10 @@ struct ethtool_ops {
 	int	(*reset)(struct net_device *, u32 *);
 	u32	(*get_rxfh_key_size)(struct net_device *);
 	u32	(*get_rxfh_indir_size)(struct net_device *);
-	int	(*get_rxfh)(struct net_device *, u32 *indir, u8 *key);
+	int	(*get_rxfh)(struct net_device *, u32 *indir, u8 *key,
+			    u8 *hfunc);
 	int	(*set_rxfh)(struct net_device *, const u32 *indir,
-			    const u8 *key);
+			    const u8 *key, const u8 hfunc);
 	void	(*get_channels)(struct net_device *, struct ethtool_channels *);
 	int	(*set_channels)(struct net_device *, struct ethtool_channels *);
 	int	(*get_dump_flag)(struct net_device *, struct ethtool_dump *);

include/uapi/linux/ethtool.h

@@ -534,6 +534,7 @@ struct ethtool_pauseparam {
  * @ETH_SS_NTUPLE_FILTERS: Previously used with %ETHTOOL_GRXNTUPLE;
  *	now deprecated
  * @ETH_SS_FEATURES: Device feature names
+ * @ETH_SS_RSS_HASH_FUNCS: RSS hush function names
  */
 enum ethtool_stringset {
 	ETH_SS_TEST		= 0,
@@ -541,6 +542,7 @@ enum ethtool_stringset {
 	ETH_SS_PRIV_FLAGS,
 	ETH_SS_NTUPLE_FILTERS,
 	ETH_SS_FEATURES,
+	ETH_SS_RSS_HASH_FUNCS,
 };
 
 /**
@@ -884,6 +886,8 @@ struct ethtool_rxfh_indir {
  * @key_size: On entry, the array size of the user buffer for the hash key,
  *	which may be zero.  On return from %ETHTOOL_GRSSH, the size of the
  *	hardware hash key.
+ * @hfunc: Defines the current RSS hash function used by HW (or to be set to).
+ *	Valid values are one of the %ETH_RSS_HASH_*.
  * @rsvd:	Reserved for future extensions.
  * @rss_config: RX ring/queue index for each hash value i.e., indirection table
  *	of @indir_size __u32 elements, followed by hash key of @key_size
@@ -893,14 +897,16 @@ struct ethtool_rxfh_indir {
  * size should be returned.  For %ETHTOOL_SRSSH, an @indir_size of
  * %ETH_RXFH_INDIR_NO_CHANGE means that indir table setting is not requested
  * and a @indir_size of zero means the indir table should be reset to default
- * values.
+ * values. An hfunc of zero means that hash function setting is not requested.
  */
 struct ethtool_rxfh {
 	__u32   cmd;
 	__u32	rss_context;
 	__u32   indir_size;
 	__u32   key_size;
-	__u32	rsvd[2];
+	__u8	hfunc;
+	__u8	rsvd8[3];
+	__u32	rsvd32;
 	__u32   rss_config[0];
 };
 #define ETH_RXFH_INDIR_NO_CHANGE	0xffffffff

net/core/ethtool.c

@@ -100,6 +100,12 @@ static const char netdev_features_strings[NETDEV_FEATURE_COUNT][ETH_GSTRING_LEN]
 	[NETIF_F_BUSY_POLL_BIT] =        "busy-poll",
 };
 
+static const char
+rss_hash_func_strings[ETH_RSS_HASH_FUNCS_COUNT][ETH_GSTRING_LEN] = {
+	[ETH_RSS_HASH_TOP_BIT] =	"toeplitz",
+	[ETH_RSS_HASH_XOR_BIT] =	"xor",
+};
+
 static int ethtool_get_features(struct net_device *dev, void __user *useraddr)
 {
 	struct ethtool_gfeatures cmd = {
@@ -185,6 +191,9 @@ static int __ethtool_get_sset_count(struct net_device *dev, int sset)
 	if (sset == ETH_SS_FEATURES)
 		return ARRAY_SIZE(netdev_features_strings);
 
+	if (sset == ETH_SS_RSS_HASH_FUNCS)
+		return ARRAY_SIZE(rss_hash_func_strings);
+
 	if (ops->get_sset_count && ops->get_strings)
 		return ops->get_sset_count(dev, sset);
 	else
@@ -199,6 +208,9 @@ static void __ethtool_get_strings(struct net_device *dev,
 	if (stringset == ETH_SS_FEATURES)
 		memcpy(data, netdev_features_strings,
 			sizeof(netdev_features_strings));
+	else if (stringset == ETH_SS_RSS_HASH_FUNCS)
+		memcpy(data, rss_hash_func_strings,
+		       sizeof(rss_hash_func_strings));
 	else
 		/* ops->get_strings is valid because checked earlier */
 		ops->get_strings(dev, stringset, data);
@@ -618,7 +630,7 @@ static noinline_for_stack int ethtool_get_rxfh_indir(struct net_device *dev,
 	if (!indir)
 		return -ENOMEM;
 
-	ret = dev->ethtool_ops->get_rxfh(dev, indir, NULL);
+	ret = dev->ethtool_ops->get_rxfh(dev, indir, NULL, NULL);
 	if (ret)
 		goto out;
 
@@ -679,7 +691,7 @@ static noinline_for_stack int ethtool_set_rxfh_indir(struct net_device *dev,
 			goto out;
 	}
 
-	ret = ops->set_rxfh(dev, indir, NULL);
+	ret = ops->set_rxfh(dev, indir, NULL, ETH_RSS_HASH_NO_CHANGE);
 
 out:
 	kfree(indir);
@@ -697,12 +709,11 @@ static noinline_for_stack int ethtool_get_rxfh(struct net_device *dev,
 	u32 total_size;
 	u32 indir_bytes;
 	u32 *indir = NULL;
+	u8 dev_hfunc = 0;
 	u8 *hkey = NULL;
 	u8 *rss_config;
 
-	if (!(dev->ethtool_ops->get_rxfh_indir_size ||
-	      dev->ethtool_ops->get_rxfh_key_size) ||
-	      !dev->ethtool_ops->get_rxfh)
+	if (!ops->get_rxfh)
 		return -EOPNOTSUPP;
 
 	if (ops->get_rxfh_indir_size)
@@ -710,16 +721,14 @@ static noinline_for_stack int ethtool_get_rxfh(struct net_device *dev,
 	if (ops->get_rxfh_key_size)
 		dev_key_size = ops->get_rxfh_key_size(dev);
 
-	if ((dev_key_size + dev_indir_size) == 0)
-		return -EOPNOTSUPP;
-
 	if (copy_from_user(&rxfh, useraddr, sizeof(rxfh)))
 		return -EFAULT;
 	user_indir_size = rxfh.indir_size;
 	user_key_size = rxfh.key_size;
 
 	/* Check that reserved fields are 0 for now */
-	if (rxfh.rss_context || rxfh.rsvd[0] || rxfh.rsvd[1])
+	if (rxfh.rss_context || rxfh.rsvd8[0] || rxfh.rsvd8[1] ||
+	    rxfh.rsvd8[2] || rxfh.rsvd32)
 		return -EINVAL;
 
 	rxfh.indir_size = dev_indir_size;
@@ -727,13 +736,6 @@ static noinline_for_stack int ethtool_get_rxfh(struct net_device *dev,
 	if (copy_to_user(useraddr, &rxfh, sizeof(rxfh)))
 		return -EFAULT;
 
-	/* If the user buffer size is 0, this is just a query for the
-	 * device table size and key size.  Otherwise, if the User size is
-	 * not equal to device table size or key size it's an error.
-	 */
-	if (!user_indir_size && !user_key_size)
-		return 0;
-
 	if ((user_indir_size && (user_indir_size != dev_indir_size)) ||
 	    (user_key_size && (user_key_size != dev_key_size)))
 		return -EINVAL;
@@ -750,14 +752,19 @@ static noinline_for_stack int ethtool_get_rxfh(struct net_device *dev,
 	if (user_key_size)
 		hkey = rss_config + indir_bytes;
 
-	ret = dev->ethtool_ops->get_rxfh(dev, indir, hkey);
-	if (!ret) {
-		if (copy_to_user(useraddr +
-				 offsetof(struct ethtool_rxfh, rss_config[0]),
-				 rss_config, total_size))
-			ret = -EFAULT;
-	}
+	ret = dev->ethtool_ops->get_rxfh(dev, indir, hkey, &dev_hfunc);
+	if (ret)
+		goto out;
 
+	if (copy_to_user(useraddr + offsetof(struct ethtool_rxfh, hfunc),
+			 &dev_hfunc, sizeof(rxfh.hfunc))) {
+		ret = -EFAULT;
+	} else if (copy_to_user(useraddr +
+			      offsetof(struct ethtool_rxfh, rss_config[0]),
+			      rss_config, total_size)) {
+		ret = -EFAULT;
+	}
+out:
 	kfree(rss_config);
 
 	return ret;
@@ -776,33 +783,31 @@ static noinline_for_stack int ethtool_set_rxfh(struct net_device *dev,
 	u8 *rss_config;
 	u32 rss_cfg_offset = offsetof(struct ethtool_rxfh, rss_config[0]);
 
-	if (!(ops->get_rxfh_indir_size || ops->get_rxfh_key_size) ||
-	    !ops->get_rxnfc || !ops->set_rxfh)
+	if (!ops->get_rxnfc || !ops->set_rxfh)
 		return -EOPNOTSUPP;
 
 	if (ops->get_rxfh_indir_size)
 		dev_indir_size = ops->get_rxfh_indir_size(dev);
 	if (ops->get_rxfh_key_size)
 		dev_key_size = dev->ethtool_ops->get_rxfh_key_size(dev);
-	if ((dev_key_size + dev_indir_size) == 0)
-		return -EOPNOTSUPP;
 
 	if (copy_from_user(&rxfh, useraddr, sizeof(rxfh)))
 		return -EFAULT;
 
 	/* Check that reserved fields are 0 for now */
-	if (rxfh.rss_context || rxfh.rsvd[0] || rxfh.rsvd[1])
+	if (rxfh.rss_context || rxfh.rsvd8[0] || rxfh.rsvd8[1] ||
+	    rxfh.rsvd8[2] || rxfh.rsvd32)
 		return -EINVAL;
 
-	/* If either indir or hash key is valid, proceed further.
-	 * It is not valid to request that both be unchanged.
+	/* If either indir, hash key or function is valid, proceed further.
+	 * Must request at least one change: indir size, hash key or function.
 	 */
 	if ((rxfh.indir_size &&
 	     rxfh.indir_size != ETH_RXFH_INDIR_NO_CHANGE &&
 	     rxfh.indir_size != dev_indir_size) ||
 	    (rxfh.key_size && (rxfh.key_size != dev_key_size)) ||
 	    (rxfh.indir_size == ETH_RXFH_INDIR_NO_CHANGE &&
-	     rxfh.key_size == 0))
+	     rxfh.key_size == 0 && rxfh.hfunc == ETH_RSS_HASH_NO_CHANGE))
 		return -EINVAL;
 
 	if (rxfh.indir_size != ETH_RXFH_INDIR_NO_CHANGE)
@@ -845,7 +850,7 @@ static noinline_for_stack int ethtool_set_rxfh(struct net_device *dev,
 		}
 	}
 
-	ret = ops->set_rxfh(dev, indir, hkey);
+	ret = ops->set_rxfh(dev, indir, hkey, rxfh.hfunc);
 
 out:
 	kfree(rss_config);