net: phy: Avoid polling PHY with PHY_IGNORE_INTERRUPTS

commit d5c3d846 upstream.

Commit 2c7b4921 ("phy: fix the use of PHY_IGNORE_INTERRUPT") changed
a hunk in phy_state_machine() in the PHY_RUNNING case which was not
needed. The change essentially makes the PHY library treat PHY devices
with PHY_IGNORE_INTERRUPT to keep polling for the PHY device, even
though the intent is not to do it.

Fix this by reverting that specific hunk, which makes the PHY state
machine wait for state changes, and stay in the PHY_RUNNING state for as
long as needed.

Fixes: 2c7b4921 ("phy: fix the use of PHY_IGNORE_INTERRUPT")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

drivers/net/phy/phy.c

@@ -824,10 +824,10 @@ void phy_state_machine(struct work_struct *work)
 		phydev->adjust_link(phydev->attached_dev);
 		break;
 	case PHY_RUNNING:
-		/* Only register a CHANGE if we are polling or ignoring
-		 * interrupts and link changed since latest checking.
+		/* Only register a CHANGE if we are polling and link changed
+		 * since latest checking.
 		 */
-		if (!phy_interrupt_is_valid(phydev)) {
+		if (phydev->irq == PHY_POLL) {
 			old_link = phydev->link;
 			err = phy_read_status(phydev);
 			if (err)
@@ -926,6 +926,11 @@ void phy_state_machine(struct work_struct *work)
 	if (err < 0)
 		phy_error(phydev);
 
+	/* Only re-schedule a PHY state machine change if we are polling the
+	 * PHY, if PHY_IGNORE_INTERRUPT is set, then we will be moving
+	 * between states from phy_mac_interrupt()
+	 */
+	if (phydev->irq == PHY_POLL)
 		queue_delayed_work(system_power_efficient_wq, &phydev->state_queue,
 				   PHY_STATE_TIME * HZ);
 }