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PHYLIB: Locking fixes for PHY I/O potentially sleeping 

PHY read/write functions can potentially sleep (e.g., a PHY accessed
via I2C).  The following changes were made to account for this:

    * Change spin locks to mutex locks
    * Add a BUG_ON() to phy_read() phy_write() to warn against
      calling them from an interrupt context.
    * Use work queue for PHY state machine handling since
      it can potentially sleep
    * Change phydev lock from spinlock to mutex

Signed-off-by: Nate Case <ncase@xes-inc.com>
Acked-by: Andy Fleming <afleming@freescale.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Nate Case 2008-01-29 10:05:09 -06:00 committed by David S. Miller
parent 2b91213064
commit 35b5f6b1a8
4 changed files with 55 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/net/phy/mdio_bus.c
View File

@ -49,7 +49,7 @@ int mdiobus_register(struct mii_bus *bus)
int i;
int err = 0;
spin_lock_init(&bus->mdio_lock);
mutex_init(&bus->mdio_lock);
if (NULL == bus || NULL == bus->name ||
NULL == bus->read ||

68
drivers/net/phy/phy.c
View File

@ -26,7 +26,6 @@
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/mii.h>
@ -72,9 +71,11 @@ int phy_read(struct phy_device *phydev, u16 regnum)
int retval;
struct mii_bus *bus = phydev->bus;
spin_lock_bh(&bus->mdio_lock);
BUG_ON(in_interrupt());
mutex_lock(&bus->mdio_lock);
retval = bus->read(bus, phydev->addr, regnum);
spin_unlock_bh(&bus->mdio_lock);
mutex_unlock(&bus->mdio_lock);
return retval;
}
@ -95,9 +96,11 @@ int phy_write(struct phy_device *phydev, u16 regnum, u16 val)
int err;
struct mii_bus *bus = phydev->bus;
spin_lock_bh(&bus->mdio_lock);
BUG_ON(in_interrupt());
mutex_lock(&bus->mdio_lock);
err = bus->write(bus, phydev->addr, regnum, val);
spin_unlock_bh(&bus->mdio_lock);
mutex_unlock(&bus->mdio_lock);
return err;
}
@ -428,7 +431,7 @@ int phy_start_aneg(struct phy_device *phydev)
{
int err;
spin_lock_bh(&phydev->lock);
mutex_lock(&phydev->lock);
if (AUTONEG_DISABLE == phydev->autoneg)
phy_sanitize_settings(phydev);
@ -449,13 +452,14 @@ int phy_start_aneg(struct phy_device *phydev)
}
out_unlock:
spin_unlock_bh(&phydev->lock);
mutex_unlock(&phydev->lock);
return err;
}
EXPORT_SYMBOL(phy_start_aneg);
static void phy_change(struct work_struct *work);
static void phy_state_machine(struct work_struct *work);
static void phy_timer(unsigned long data);
/**
@ -476,6 +480,7 @@ void phy_start_machine(struct phy_device *phydev,
{
phydev->adjust_state = handler;
INIT_WORK(&phydev->state_queue, phy_state_machine);
init_timer(&phydev->phy_timer);
phydev->phy_timer.function = &phy_timer;
phydev->phy_timer.data = (unsigned long) phydev;
@ -493,11 +498,12 @@ void phy_start_machine(struct phy_device *phydev,
void phy_stop_machine(struct phy_device *phydev)
{
del_timer_sync(&phydev->phy_timer);
cancel_work_sync(&phydev->state_queue);
spin_lock_bh(&phydev->lock);
mutex_lock(&phydev->lock);
if (phydev->state > PHY_UP)
phydev->state = PHY_UP;
spin_unlock_bh(&phydev->lock);
mutex_unlock(&phydev->lock);
phydev->adjust_state = NULL;
}
@ -541,9 +547,9 @@ static void phy_force_reduction(struct phy_device *phydev)
*/
void phy_error(struct phy_device *phydev)
{
spin_lock_bh(&phydev->lock);
mutex_lock(&phydev->lock);
phydev->state = PHY_HALTED;
spin_unlock_bh(&phydev->lock);
mutex_unlock(&phydev->lock);
}
/**
@ -705,10 +711,10 @@ static void phy_change(struct work_struct *work)
if (err)
goto phy_err;
spin_lock_bh(&phydev->lock);
mutex_lock(&phydev->lock);
if ((PHY_RUNNING == phydev->state) || (PHY_NOLINK == phydev->state))
phydev->state = PHY_CHANGELINK;
spin_unlock_bh(&phydev->lock);
mutex_unlock(&phydev->lock);
atomic_dec(&phydev->irq_disable);
enable_irq(phydev->irq);
@ -735,7 +741,7 @@ phy_err:
*/
void phy_stop(struct phy_device *phydev)
{
spin_lock_bh(&phydev->lock);
mutex_lock(&phydev->lock);
if (PHY_HALTED == phydev->state)
goto out_unlock;
@ -751,7 +757,7 @@ void phy_stop(struct phy_device *phydev)
phydev->state = PHY_HALTED;
out_unlock:
spin_unlock_bh(&phydev->lock);
mutex_unlock(&phydev->lock);
/*
* Cannot call flush_scheduled_work() here as desired because
@ -773,7 +779,7 @@ out_unlock:
*/
void phy_start(struct phy_device *phydev)
{
spin_lock_bh(&phydev->lock);
mutex_lock(&phydev->lock);
switch (phydev->state) {
case PHY_STARTING:
@ -787,19 +793,26 @@ void phy_start(struct phy_device *phydev)
default:
break;
}
spin_unlock_bh(&phydev->lock);
mutex_unlock(&phydev->lock);
}
EXPORT_SYMBOL(phy_stop);
EXPORT_SYMBOL(phy_start);
/* PHY timer which handles the state machine */
static void phy_timer(unsigned long data)
/**
* phy_state_machine - Handle the state machine
* @work: work_struct that describes the work to be done
*
* Description: Scheduled by the state_queue workqueue each time
* phy_timer is triggered.
*/
static void phy_state_machine(struct work_struct *work)
{
struct phy_device *phydev = (struct phy_device *)data;
struct phy_device *phydev =
container_of(work, struct phy_device, state_queue);
int needs_aneg = 0;
int err = 0;
spin_lock_bh(&phydev->lock);
mutex_lock(&phydev->lock);
if (phydev->adjust_state)
phydev->adjust_state(phydev->attached_dev);
@ -965,7 +978,7 @@ static void phy_timer(unsigned long data)
break;
}
spin_unlock_bh(&phydev->lock);
mutex_unlock(&phydev->lock);
if (needs_aneg)
err = phy_start_aneg(phydev);
@ -976,3 +989,14 @@ static void phy_timer(unsigned long data)
mod_timer(&phydev->phy_timer, jiffies + PHY_STATE_TIME * HZ);
}
/* PHY timer which schedules the state machine work */
static void phy_timer(unsigned long data)
{
struct phy_device *phydev = (struct phy_device *)data;
/*
* PHY I/O operations can potentially sleep so we ensure that
* it's done from a process context
*/
schedule_work(&phydev->state_queue);
}

11
drivers/net/phy/phy_device.c
View File

@ -25,7 +25,6 @@
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/mii.h>
@ -80,7 +79,7 @@ struct phy_device* phy_device_create(struct mii_bus *bus, int addr, int phy_id)
dev->state = PHY_DOWN;
spin_lock_init(&dev->lock);
mutex_init(&dev->lock);
return dev;
}
@ -656,7 +655,7 @@ static int phy_probe(struct device *dev)
if (!(phydrv->flags & PHY_HAS_INTERRUPT))
phydev->irq = PHY_POLL;
spin_lock_bh(&phydev->lock);
mutex_lock(&phydev->lock);
/* Start out supporting everything. Eventually,
* a controller will attach, and may modify one
@ -670,7 +669,7 @@ static int phy_probe(struct device *dev)
if (phydev->drv->probe)
err = phydev->drv->probe(phydev);
spin_unlock_bh(&phydev->lock);
mutex_unlock(&phydev->lock);
return err;
@ -682,9 +681,9 @@ static int phy_remove(struct device *dev)
phydev = to_phy_device(dev);
spin_lock_bh(&phydev->lock);
mutex_lock(&phydev->lock);
phydev->state = PHY_DOWN;
spin_unlock_bh(&phydev->lock);
mutex_unlock(&phydev->lock);
if (phydev->drv->remove)
phydev->drv->remove(phydev);

5
include/linux/phy.h
View File

@ -88,7 +88,7 @@ struct mii_bus {
/* A lock to ensure that only one thing can read/write
* the MDIO bus at a time */
spinlock_t mdio_lock;
struct mutex mdio_lock;
struct device *dev;
@ -284,10 +284,11 @@ struct phy_device {
/* Interrupt and Polling infrastructure */
struct work_struct phy_queue;
struct work_struct state_queue;
struct timer_list phy_timer;
atomic_t irq_disable;
spinlock_t lock;
struct mutex lock;
struct net_device *attached_dev;