igbvf: avoid reset storms due to mailbox issues

From: Alexander Duyck <alexander.h.duyck@intel.com>

This change makes it so that reset/interrupt storms can be avoided when
there are mailbox issues.  The new behavior is to only allow the device to
trigger mailbox related resets only once every 10 seconds.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/igbvf/igbvf.h

@@ -276,6 +276,7 @@ struct igbvf_adapter {
 	unsigned long led_status;
 
 	unsigned int flags;
+	unsigned long last_reset;
 };
 
 struct igbvf_info {

drivers/net/igbvf/netdev.c

@@ -1469,6 +1469,8 @@ static void igbvf_reset(struct igbvf_adapter *adapter)
 		memcpy(netdev->perm_addr, adapter->hw.mac.addr,
 		       netdev->addr_len);
 	}
+
+	adapter->last_reset = jiffies;
 }
 
 int igbvf_up(struct igbvf_adapter *adapter)
@@ -1812,11 +1814,15 @@ static bool igbvf_has_link(struct igbvf_adapter *adapter)
 	s32 ret_val = E1000_SUCCESS;
 	bool link_active;
 
+	/* If interface is down, stay link down */
+	if (test_bit(__IGBVF_DOWN, &adapter->state))
+		return false;
+
 	ret_val = hw->mac.ops.check_for_link(hw);
 	link_active = !hw->mac.get_link_status;
 
 	/* if check for link returns error we will need to reset */
-	if (ret_val)
+	if (ret_val && time_after(jiffies, adapter->last_reset + (10 * HZ)))
 		schedule_work(&adapter->reset_task);
 
 	return link_active;