[PATCH 3.16.y-ckt 130/131] net: phy: fix PHY_RUNNING in phy_state_machine

[Luis Henriques]

3.16.7-ckt25 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Shaohui Xie <Shaohui.Xie@xxxxxxxxxxxxx>

commit 11e122cbe90ea5079622fb57bdf2dffe8cf68e57 upstream.

Currently, if phy state is PHY_RUNNING, we always register a CHANGE
when phy works in polling or interrupt ignored, this will make the
adjust_link being called even the phy link did Not changed.

checking the phy link to make sure the link did changed before we
register a CHANGE, if link did not changed, we do nothing.

Signed-off-by: Shaohui Xie <Shaohui.Xie@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
 drivers/net/phy/phy.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index ccfc44cfcee8..8f2e0fd0c9ca 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -740,6 +740,7 @@ void phy_state_machine(struct work_struct *work)
 			container_of(dwork, struct phy_device, state_queue);
 	bool needs_aneg = false, do_suspend = false, do_resume = false;
 	int err = 0;
+	int old_link;
 
 	mutex_lock(&phydev->lock);
 
@@ -823,11 +824,18 @@ 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
+		/* Only register a CHANGE if we are polling or ignoring
+		 * interrupts and link changed since latest checking.
 		 */
-		if (!phy_interrupt_is_valid(phydev))
-			phydev->state = PHY_CHANGELINK;
+		if (!phy_interrupt_is_valid(phydev)) {
+			old_link = phydev->link;
+			err = phy_read_status(phydev);
+			if (err)
+				break;
+
+			if (old_link != phydev->link)
+				phydev->state = PHY_CHANGELINK;
+		}
 		break;
 	case PHY_CHANGELINK:
 		err = phy_read_status(phydev);