Commit 21796261 authored Jan 23, 2019 by Heiner Kallweit Committed by David S. Miller Jan 24, 2019

net: phy: warn if phy_start is called from invalid state



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.

Some more background:
For all invalid states phy_start() basically was a no-op. All it did
was triggering a state machine run, but for all "running" states the
poll loop was active anyway. And if called from PHY_DOWN, the state
machine does nothing.

v3:
- extended commit message

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent a016becd

drivers/net/phy/phy.c

+9 −2

Original line number	Diff line number	Diff line
		@@ -856,9 +856,16 @@ 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 */
		@@ -872,13 +879,13 @@ 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);

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