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>
diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index 7c9e6e3..12fccb1 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -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 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 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 err;
- spin_lock_bh(&phydev->lock);
+ mutex_lock(&phydev->lock);
if (AUTONEG_DISABLE == phydev->autoneg)
phy_sanitize_settings(phydev);
@@ -449,13 +452,14 @@
}
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 @@
{
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_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 @@
*/
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 @@
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 @@
*/
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 @@
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 @@
*/
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 @@
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 @@
break;
}
- spin_unlock_bh(&phydev->lock);
+ mutex_unlock(&phydev->lock);
if (needs_aneg)
err = phy_start_aneg(phydev);
@@ -976,3 +989,14 @@
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);
+}