[PATCH net] net: phy: Avoid multiple suspends

From: Florian Fainelli
Date: Thu Feb 20 2020 - 18:35:01 EST

It is currently possible for a PHY device to be suspended as part of a
network device driver's suspend call while it is still being attached to
that net_device, either via phy_suspend() or implicitly via phy_stop().

Later on, when the MDIO bus controller get suspended, we would attempt
to suspend again the PHY because it is still attached to a network

This is both a waste of time and creates an opportunity for improper
clock/power management bugs to creep in.

Fixes: 803dd9c77ac3 ("net: phy: avoid suspending twice a PHY")
Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
Heiner, Andrew,

I did consider adding logic that would check for phydev->suspended in
phy_suspend() and phy_resume(), but this was really the only place where
I found it to be problematic.

drivers/net/phy/phy_device.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 6a5056e0ae77..6131aca79823 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -247,7 +247,7 @@ static bool mdio_bus_phy_may_suspend(struct phy_device *phydev)
* MDIO bus driver and clock gated at this point.
if (!netdev)
- return !phydev->suspended;
+ goto out;

if (netdev->wol_enabled)
return false;
@@ -267,7 +267,8 @@ static bool mdio_bus_phy_may_suspend(struct phy_device *phydev)
if (device_may_wakeup(&netdev->dev))
return false;

- return true;
+ return !phydev->suspended;

static int mdio_bus_phy_suspend(struct device *dev)