[PATCH net-next v2 2/4] net: phy: warn if phy_start is called from invalid state

[Heiner Kallweit <hkallweit1@gmail.com>]

phy_start() should be called from states PHY_READY or PHY_HALTED only.
Check for this to detect misbehaving drivers. Also the state machine
should be started only when being called from one of the valid states.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 drivers/net/phy/phy.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index 3df6aadc5..fd928979b 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -861,9 +861,16 @@ void phy_start(struct phy_device *phydev)
 
 	mutex_lock(&phydev->lock);
 
+	if (phydev->state != PHY_READY && phydev->state != PHY_HALTED) {
+		WARN(1, "called from state %s\n",
+		     phy_state_to_str(phydev->state));
+		goto out;
+	}
+
 	switch (phydev->state) {
 	case PHY_READY:
 		phydev->state = PHY_UP;
+		phy_start_machine(phydev);
 		break;
 	case PHY_HALTED:
 		/* if phy was suspended, bring the physical link up again */
@@ -877,13 +884,13 @@ void phy_start(struct phy_device *phydev)
 		}
 
 		phydev->state = PHY_RESUMING;
+		phy_start_machine(phydev);
 		break;
 	default:
 		break;
 	}
+out:
 	mutex_unlock(&phydev->lock);
-
-	phy_start_machine(phydev);
 }
 EXPORT_SYMBOL(phy_start);
 
-- 
2.20.1