[PATCH 4.15 081/122] net: phy: Restore phy_resume() locking assumption

From: Greg Kroah-Hartman
Date: Wed Mar 07 2018 - 15:30:40 EST


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

------------------

From: Andrew Lunn <andrew@xxxxxxx>


[ Upstream commit 9c2c2e62df3fa30fb13fbeb7512a4eede729383b ]

commit f5e64032a799 ("net: phy: fix resume handling") changes the
locking semantics for phy_resume() such that the caller now needs to
hold the phy mutex. Not all call sites were adopted to this new
semantic, resulting in warnings from the added
WARN_ON(!mutex_is_locked(&phydev->lock)). Rather than change the
semantics, add a __phy_resume() and restore the old behavior of
phy_resume().

Reported-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
Fixes: f5e64032a799 ("net: phy: fix resume handling")
Signed-off-by: Andrew Lunn <andrew@xxxxxxx>
Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/phy/phy.c | 2 +-
drivers/net/phy/phy_device.c | 18 +++++++++++++-----
include/linux/phy.h | 1 +
3 files changed, 15 insertions(+), 6 deletions(-)

--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -841,7 +841,7 @@ void phy_start(struct phy_device *phydev
break;
case PHY_HALTED:
/* if phy was suspended, bring the physical link up again */
- phy_resume(phydev);
+ __phy_resume(phydev);

/* make sure interrupts are re-enabled for the PHY */
if (phy_interrupt_is_valid(phydev)) {
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -135,9 +135,7 @@ static int mdio_bus_phy_resume(struct de
if (!mdio_bus_phy_may_suspend(phydev))
goto no_resume;

- mutex_lock(&phydev->lock);
ret = phy_resume(phydev);
- mutex_unlock(&phydev->lock);
if (ret < 0)
return ret;

@@ -1028,9 +1026,7 @@ int phy_attach_direct(struct net_device
if (err)
goto error;

- mutex_lock(&phydev->lock);
phy_resume(phydev);
- mutex_unlock(&phydev->lock);
phy_led_triggers_register(phydev);

return err;
@@ -1156,7 +1152,7 @@ int phy_suspend(struct phy_device *phyde
}
EXPORT_SYMBOL(phy_suspend);

-int phy_resume(struct phy_device *phydev)
+int __phy_resume(struct phy_device *phydev)
{
struct phy_driver *phydrv = to_phy_driver(phydev->mdio.dev.driver);
int ret = 0;
@@ -1173,6 +1169,18 @@ int phy_resume(struct phy_device *phydev

return ret;
}
+EXPORT_SYMBOL(__phy_resume);
+
+int phy_resume(struct phy_device *phydev)
+{
+ int ret;
+
+ mutex_lock(&phydev->lock);
+ ret = __phy_resume(phydev);
+ mutex_unlock(&phydev->lock);
+
+ return ret;
+}
EXPORT_SYMBOL(phy_resume);

int phy_loopback(struct phy_device *phydev, bool enable)
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -819,6 +819,7 @@ void phy_device_remove(struct phy_device
int phy_init_hw(struct phy_device *phydev);
int phy_suspend(struct phy_device *phydev);
int phy_resume(struct phy_device *phydev);
+int __phy_resume(struct phy_device *phydev);
int phy_loopback(struct phy_device *phydev, bool enable);
struct phy_device *phy_attach(struct net_device *dev, const char *bus_id,
phy_interface_t interface);