net-next:v4: Add support to configure SR-IOV VF minimum and maximum Tx rate through ip tool.

o min_tx_rate puts lower limit on the VF bandwidth. VF is guaranteed
  to have a bandwidth of at least this value.
  max_tx_rate puts cap on the VF bandwidth. VF can have a bandwidth
  of up to this value.

o A new handler set_vf_rate for attr IFLA_VF_RATE has been introduced
  which takes 4 arguments:
  netdev, VF number, min_tx_rate, max_tx_rate

o ndo_set_vf_rate replaces ndo_set_vf_tx_rate handler.

o Drivers that currently implement ndo_set_vf_tx_rate should now call
  ndo_set_vf_rate instead and reject attempt to set a minimum bandwidth
  greater than 0 for IFLA_VF_TX_RATE when IFLA_VF_RATE is not yet
  implemented by driver.

o If user enters only one of either min_tx_rate or max_tx_rate, then,
  userland should read back the other value from driver and set both
  for IFLA_VF_RATE.
  Drivers that have not yet implemented IFLA_VF_RATE should always
  return min_tx_rate as 0 when read from ip tool.

o If both IFLA_VF_TX_RATE and IFLA_VF_RATE options are specified, then
  IFLA_VF_RATE should override.

o Idea is to have consistent display of rate values to user.

o Usage example: -

  ./ip link set p4p1 vf 0 rate 900

  ./ip link show p4p1
  32: p4p1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode
  DEFAULT qlen 1000
    link/ether 00:0e:1e:08:b0:f0 brd ff:ff:ff:ff:ff:ff
    vf 0 MAC 3e:a0:ca:bd:ae:5a, tx rate 900 (Mbps), max_tx_rate 900Mbps
    vf 1 MAC f6:c6:7c:3f:3d:6c
    vf 2 MAC 56:32:43:98:d7:71
    vf 3 MAC d6:be:c3:b5:85:ff
    vf 4 MAC ee:a9:9a:1e:19:14
    vf 5 MAC 4a:d0:4c:07:52:18
    vf 6 MAC 3a:76:44:93:62:f9
    vf 7 MAC 82:e9:e7:e3:15:1a

  ./ip link set p4p1 vf 0 max_tx_rate 300 min_tx_rate 200

  ./ip link show p4p1
  32: p4p1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode
  DEFAULT qlen 1000
    link/ether 00:0e:1e:08:b0:f0 brd ff:ff:ff:ff:ff:ff
    vf 0 MAC 3e:a0:ca:bd:ae:5a, tx rate 300 (Mbps), max_tx_rate 300Mbps,
    min_tx_rate 200Mbps
    vf 1 MAC f6:c6:7c:3f:3d:6c
    vf 2 MAC 56:32:43:98:d7:71
    vf 3 MAC d6:be:c3:b5:85:ff
    vf 4 MAC ee:a9:9a:1e:19:14
    vf 5 MAC 4a:d0:4c:07:52:18
    vf 6 MAC 3a:76:44:93:62:f9
    vf 7 MAC 82:e9:e7:e3:15:1a

  ./ip link set p4p1 vf 0 max_tx_rate 600 rate 300

  ./ip link show p4p1
  32: p4p1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode
  DEFAULT qlen 1000
    link/ether 00:0e:1e:08:b0:f brd ff:ff:ff:ff:ff:ff
    vf 0 MAC 3e:a0:ca:bd:ae:5, tx rate 600 (Mbps), max_tx_rate 600Mbps,
    min_tx_rate 200Mbps
    vf 1 MAC f6:c6:7c:3f:3d:6c
    vf 2 MAC 56:32:43:98:d7:71
    vf 3 MAC d6:be:c3:b5:85:ff
    vf 4 MAC ee:a9:9a:1e:19:14
    vf 5 MAC 4a:d0:4c:07:52:18
    vf 6 MAC 3a:76:44:93:62:f9
    vf 7 MAC 82:e9:e7:e3:15:1a

Signed-off-by: Sucheta Chakraborty <sucheta.chakraborty@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
index 4d21956..8564b09 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
@@ -2205,7 +2205,8 @@
  *
  * configure vf tx rate
  **/
-int i40e_ndo_set_vf_bw(struct net_device *netdev, int vf_id, int tx_rate)
+int i40e_ndo_set_vf_bw(struct net_device *netdev, int vf_id, int min_tx_rate,
+		       int max_tx_rate)
 {
 	struct i40e_netdev_priv *np = netdev_priv(netdev);
 	struct i40e_pf *pf = np->vsi->back;
@@ -2221,6 +2222,12 @@
 		goto error;
 	}
 
+	if (min_tx_rate) {
+		dev_err(&pf->pdev->dev, "Invalid min tx rate (%d) (greater than 0) specified for vf %d.\n",
+			min_tx_rate, vf_id);
+		return -EINVAL;
+	}
+
 	vf = &(pf->vf[vf_id]);
 	vsi = pf->vsi[vf->lan_vsi_index];
 	if (!test_bit(I40E_VF_STAT_INIT, &vf->vf_states)) {
@@ -2243,23 +2250,23 @@
 		break;
 	}
 
-	if (tx_rate > speed) {
-		dev_err(&pf->pdev->dev, "Invalid tx rate %d specified for vf %d.",
-			tx_rate, vf->vf_id);
+	if (max_tx_rate > speed) {
+		dev_err(&pf->pdev->dev, "Invalid max tx rate %d specified for vf %d.",
+			max_tx_rate, vf->vf_id);
 		ret = -EINVAL;
 		goto error;
 	}
 
 	/* Tx rate credits are in values of 50Mbps, 0 is disabled*/
-	ret = i40e_aq_config_vsi_bw_limit(&pf->hw, vsi->seid, tx_rate / 50, 0,
-					  NULL);
+	ret = i40e_aq_config_vsi_bw_limit(&pf->hw, vsi->seid, max_tx_rate / 50,
+					  0, NULL);
 	if (ret) {
-		dev_err(&pf->pdev->dev, "Unable to set tx rate, error code %d.\n",
+		dev_err(&pf->pdev->dev, "Unable to set max tx rate, error code %d.\n",
 			ret);
 		ret = -EIO;
 		goto error;
 	}
-	vf->tx_rate = tx_rate;
+	vf->tx_rate = max_tx_rate;
 error:
 	return ret;
 }
@@ -2301,7 +2308,8 @@
 
 	memcpy(&ivi->mac, vf->default_lan_addr.addr, ETH_ALEN);
 
-	ivi->tx_rate = vf->tx_rate;
+	ivi->max_tx_rate = vf->tx_rate;
+	ivi->min_tx_rate = 0;
 	ivi->vlan = le16_to_cpu(vsi->info.pvid) & I40E_VLAN_MASK;
 	ivi->qos = (le16_to_cpu(vsi->info.pvid) & I40E_PRIORITY_MASK) >>
 		   I40E_VLAN_PRIORITY_SHIFT;