igb: add code to retry a phy read in the event of failure on link check

This patch adds a retry to phy reads in the event of failure.  The original
code broke out of the loop on failure and this is a mistake as we should be
trying to do the read twice.

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/igb/e1000_phy.c

@@ -1444,8 +1444,14 @@ s32 igb_phy_has_link(struct e1000_hw *hw, u32 iterations,
 		 * it across the board.
 		 */
 		ret_val = hw->phy.ops.read_reg(hw, PHY_STATUS, &phy_status);
-		if (ret_val)
-			break;
+		if (ret_val) {
+			/*
+			 * If the first read fails, another entity may have
+			 * ownership of the resources, wait and try again to
+			 * see if they have relinquished the resources yet.
+			 */
+			udelay(usec_interval);
+		}
 		ret_val = hw->phy.ops.read_reg(hw, PHY_STATUS, &phy_status);
 		if (ret_val)
 			break;