netdev - [PATCH net] net: phy: Run state machine to completion

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Date:   Wed, 26 Jul 2017 12:24:46 -0700
From:   Florian Fainelli <f.fainelli@...il.com>
To:     netdev@...r.kernel.org
Cc:     rmk+kernel@...linux.org.uk, slash.tmp@...e.fr, zach.brown@...com,
        nathan.sullivan@...com, Florian Fainelli <f.fainelli@...il.com>,
        Andrew Lunn <andrew@...n.ch>,
        linux-kernel@...r.kernel.org (open list)
Subject: [PATCH net] net: phy: Run state machine to completion

Marc reported that he was not getting the PHY library adjust_link()
callback function to run when calling phy_stop() + phy_disconnect()
which does not indeed happen because we don't make sure we flush the
PHYLIB delayed work and let it run to completion. We also need to have
a synchronous call to phy_state_machine() in order to have the state
machine actually act on PHY_HALTED, set the PHY device's link down, turn
the network device's carrier off and finally call the adjust_link()
function.

Reported-by: Marc Gonzalez <marc_gonzalez@...madesigns.com>
Fixes: a390d1f379cf ("phylib: convert state_queue work to delayed_work")
Signed-off-by: Florian Fainelli <f.fainelli@...il.com>
---
David, this dates back from before the commit mentioned in Fixes but it would
be hard to backport to earlier kernels if we flagged the original design flaw
that used timers. Also, I am not clear on the timer API whether there was a way
to ensure timers would run to completion before they would be cancelled.

Marc, please add your Signed-off-by tag since you contributed the second line.

Thanks!

 drivers/net/phy/phy.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index d0626bf5c540..30e7c43e0d87 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -743,12 +743,17 @@ void phy_trigger_machine(struct phy_device *phydev, bool sync)
  */
 void phy_stop_machine(struct phy_device *phydev)
 {
+	/* Run the state machine to completion */
+	flush_delayed_work(&phydev->state_queue);
 	cancel_delayed_work_sync(&phydev->state_queue);
 
 	mutex_lock(&phydev->lock);
 	if (phydev->state > PHY_UP && phydev->state != PHY_HALTED)
 		phydev->state = PHY_UP;
 	mutex_unlock(&phydev->lock);
+
+	/* Now we can run the state machine synchronously */
+	phy_state_machine(&phydev->state_queue.work);
 }
 
 /**
-- 
2.9.3