net: fix DCB setstate to return success/failure

Data Center Bridging (DCB) had no way to know if setstate had failed in the
driver.  This patch enables dcb netlink code to handle the status for the DCB
setstate interface.  Likewise it allows the driver to return a failed status
if MSI-X isn't enabled.

Signed-off-by: Don Skidmore <donald.c.skidmore@intel.com>
Signed-off-by: Eric W Multanen <eric.w.multanen@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ixgbe/ixgbe_dcb_nl.c

@@ -124,39 +124,45 @@ static u16 ixgbe_dcb_select_queue(struct net_device *dev, struct sk_buff *skb)
 	return 0;
 }
 
-static void ixgbe_dcbnl_set_state(struct net_device *netdev, u8 state)
+static u8 ixgbe_dcbnl_set_state(struct net_device *netdev, u8 state)
 {
+	u8 err = 0;
 	struct ixgbe_adapter *adapter = netdev_priv(netdev);
 
 	DPRINTK(DRV, INFO, "Set DCB Admin Mode.\n");
 
 	if (state > 0) {
 		/* Turn on DCB */
-		if (adapter->flags & IXGBE_FLAG_DCB_ENABLED) {
-			return;
-		} else {
-			if (netif_running(netdev))
-				netdev->stop(netdev);
-			ixgbe_reset_interrupt_capability(adapter);
-			ixgbe_napi_del_all(adapter);
-			kfree(adapter->tx_ring);
-			kfree(adapter->rx_ring);
-			adapter->tx_ring = NULL;
-			adapter->rx_ring = NULL;
-			netdev->select_queue = &ixgbe_dcb_select_queue;
+		if (adapter->flags & IXGBE_FLAG_DCB_ENABLED)
+			goto out;
 
-			adapter->flags &= ~IXGBE_FLAG_RSS_ENABLED;
-			adapter->flags |= IXGBE_FLAG_DCB_ENABLED;
-			ixgbe_init_interrupt_scheme(adapter);
-			ixgbe_napi_add_all(adapter);
-			if (netif_running(netdev))
-				netdev->open(netdev);
+		if (!(adapter->flags & IXGBE_FLAG_MSIX_ENABLED)) {
+			DPRINTK(DRV, ERR, "Enable failed, needs MSI-X\n");
+			err = 1;
+			goto out;
 		}
+
+		if (netif_running(netdev))
+			netdev->netdev_ops->ndo_stop(netdev);
+		ixgbe_reset_interrupt_capability(adapter);
+		ixgbe_napi_del_all(adapter);
+		kfree(adapter->tx_ring);
+		kfree(adapter->rx_ring);
+		adapter->tx_ring = NULL;
+		adapter->rx_ring = NULL;
+		netdev->select_queue = &ixgbe_dcb_select_queue;
+
+		adapter->flags &= ~IXGBE_FLAG_RSS_ENABLED;
+		adapter->flags |= IXGBE_FLAG_DCB_ENABLED;
+		ixgbe_init_interrupt_scheme(adapter);
+		ixgbe_napi_add_all(adapter);
+		if (netif_running(netdev))
+			netdev->netdev_ops->ndo_open(netdev);
 	} else {
 		/* Turn off DCB */
 		if (adapter->flags & IXGBE_FLAG_DCB_ENABLED) {
 			if (netif_running(netdev))
-				netdev->stop(netdev);
+				netdev->netdev_ops->ndo_stop(netdev);
 			ixgbe_reset_interrupt_capability(adapter);
 			ixgbe_napi_del_all(adapter);
 			kfree(adapter->tx_ring);
@@ -170,11 +176,11 @@ static void ixgbe_dcbnl_set_state(struct net_device *netdev, u8 state)
 			ixgbe_init_interrupt_scheme(adapter);
 			ixgbe_napi_add_all(adapter);
 			if (netif_running(netdev))
-				netdev->open(netdev);
-		} else {
-			return;
+				netdev->netdev_ops->ndo_open(netdev);
 		}
 	}
+out:
+	return err;
 }
 
 static void ixgbe_dcbnl_get_perm_hw_addr(struct net_device *netdev,

include/net/dcbnl.h

@@ -26,7 +26,7 @@
  */
 struct dcbnl_rtnl_ops {
 	u8   (*getstate)(struct net_device *);
-	void (*setstate)(struct net_device *, u8);
+	u8   (*setstate)(struct net_device *, u8);
 	void (*getpermhwaddr)(struct net_device *, u8 *);
 	void (*setpgtccfgtx)(struct net_device *, int, u8, u8, u8, u8);
 	void (*setpgbwgcfgtx)(struct net_device *, int, u8);

net/dcb/dcbnl.c

@@ -714,9 +714,8 @@ static int dcbnl_setstate(struct net_device *netdev, struct nlattr **tb,
 
 	value = nla_get_u8(tb[DCB_ATTR_STATE]);
 
-	netdev->dcbnl_ops->setstate(netdev, value);
-
-	ret = dcbnl_reply(0, RTM_SETDCB, DCB_CMD_SSTATE, DCB_ATTR_STATE,
+	ret = dcbnl_reply(netdev->dcbnl_ops->setstate(netdev, value),
+	                  RTM_SETDCB, DCB_CMD_SSTATE, DCB_ATTR_STATE,
 	                  pid, seq, flags);
 
 	return ret;