Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 05a7f582 authored by Russell King's avatar Russell King Committed by David S. Miller
Browse files

net: phy: add locking to phy_read_mmd_indirect()/phy_write_mmd_indirect() 



The phy layer is missing locking for the above two functions - it
has been observed that two threads (userspace and the phy worker
thread) can race, entering the bus ->write or ->read functions
simultaneously.

This causes the FEC driver to initialise a completion while another
thread is waiting on it or while the interrupt is calling complete()
on it, which causes spinlock unlock-without-lock, spinlock lockups,
and completion timeouts.

Fixes: a59a4d19 ("phy: add the EEE support and the way to access to the MMD registers.")
Fixes: 0c1d77df ("net: libphy: Add phy specific function to access mmd phy registers")
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
Acked-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent bef0057b

drivers/net/phy/phy.c

+12 −4
Original line number Original line Diff line number Diff line
@@ -1038,10 +1038,14 @@ int phy_read_mmd_indirect(struct phy_device *phydev, int prtad, 
	int value = -1;

	int value = -1;





	if (phydrv->read_mmd_indirect == NULL) {

	if (phydrv->read_mmd_indirect == NULL) {

		mmd_phy_indirect(phydev->bus, prtad, devad, addr);

		struct mii_bus *bus = phydev->bus;



		mutex_lock(&bus->mdio_lock);

		mmd_phy_indirect(bus, prtad, devad, addr);





		/* Read the content of the MMD's selected register */

		/* Read the content of the MMD's selected register */

		value = phydev->bus->read(phydev->bus, addr, MII_MMD_DATA);

		value = bus->read(bus, addr, MII_MMD_DATA);

		mutex_unlock(&bus->mdio_lock);

	} else {

	} else {

		value = phydrv->read_mmd_indirect(phydev, prtad, devad, addr);

		value = phydrv->read_mmd_indirect(phydev, prtad, devad, addr);

	}

	}
@@ -1071,10 +1075,14 @@ void phy_write_mmd_indirect(struct phy_device *phydev, int prtad, 
	struct phy_driver *phydrv = phydev->drv;

	struct phy_driver *phydrv = phydev->drv;





	if (phydrv->write_mmd_indirect == NULL) {

	if (phydrv->write_mmd_indirect == NULL) {

		mmd_phy_indirect(phydev->bus, prtad, devad, addr);

		struct mii_bus *bus = phydev->bus;



		mutex_lock(&bus->mdio_lock);

		mmd_phy_indirect(bus, prtad, devad, addr);





		/* Write the data into MMD's selected register */

		/* Write the data into MMD's selected register */

		phydev->bus->write(phydev->bus, addr, MII_MMD_DATA, data);

		bus->write(bus, addr, MII_MMD_DATA, data);

		mutex_unlock(&bus->mdio_lock);

	} else {

	} else {

		phydrv->write_mmd_indirect(phydev, prtad, devad, addr, data);

		phydrv->write_mmd_indirect(phydev, prtad, devad, addr, data);

	}

	}