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phylib: convert state_queue work to delayed_work

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It closes a race in phy_stop_machine when reprogramming of phy_timer
(from phy_state_machine) happens between del_timer_sync and cancel_work_sync.

Without this change it could lead to crash if phy_device would be freed after
phy_stop_machine (timer would fire and schedule freed work).

Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Marcin Slusarz 2009-03-13 15:41:19 -07:00 committed by David S. Miller
parent 34cd347cec
commit a390d1f379
2 changed files with 12 additions and 32 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

41
drivers/net/phy/phy.c
View file

@ -414,7 +414,6 @@ EXPORT_SYMBOL(phy_start_aneg);
static void phy_change(struct work_struct *work); static void phy_change(struct work_struct *work);
static void phy_state_machine(struct work_struct *work); static void phy_state_machine(struct work_struct *work);
static void phy_timer(unsigned long data);
/** /**
* phy_start_machine - start PHY state machine tracking * phy_start_machine - start PHY state machine tracking
@ -434,11 +433,8 @@ void phy_start_machine(struct phy_device *phydev,
{ {
phydev->adjust_state = handler; phydev->adjust_state = handler;
INIT_WORK(&phydev->state_queue, phy_state_machine); INIT_DELAYED_WORK(&phydev->state_queue, phy_state_machine);
init_timer(&phydev->phy_timer); schedule_delayed_work(&phydev->state_queue, jiffies + HZ);
phydev->phy_timer.function = &phy_timer;
phydev->phy_timer.data = (unsigned long) phydev;
mod_timer(&phydev->phy_timer, jiffies + HZ);
} }
/** /**
@ -451,8 +447,7 @@ void phy_start_machine(struct phy_device *phydev,
*/ */
void phy_stop_machine(struct phy_device *phydev) void phy_stop_machine(struct phy_device *phydev)
{ {
del_timer_sync(&phydev->phy_timer); cancel_delayed_work_sync(&phydev->state_queue);
cancel_work_sync(&phydev->state_queue);
mutex_lock(&phydev->lock); mutex_lock(&phydev->lock);
if (phydev->state > PHY_UP) if (phydev->state > PHY_UP)
@ -680,11 +675,9 @@ static void phy_change(struct work_struct *work)
if (err) if (err)
goto irq_enable_err; goto irq_enable_err;
/* Stop timer and run the state queue now. The work function for /* reschedule state queue work to run as soon as possible */
* state_queue will start the timer up again. cancel_delayed_work_sync(&phydev->state_queue);
*/ schedule_delayed_work(&phydev->state_queue, 0);
del_timer(&phydev->phy_timer);
schedule_work(&phydev->state_queue);
return; return;
@ -761,14 +754,13 @@ EXPORT_SYMBOL(phy_start);
/** /**
* phy_state_machine - Handle the state machine * phy_state_machine - Handle the state machine
* @work: work_struct that describes the work to be done * @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) static void phy_state_machine(struct work_struct *work)
{ {
struct delayed_work *dwork =
container_of(work, struct delayed_work, work);
struct phy_device *phydev = struct phy_device *phydev =
container_of(work, struct phy_device, state_queue); container_of(dwork, struct phy_device, state_queue);
int needs_aneg = 0; int needs_aneg = 0;
int err = 0; int err = 0;
@ -946,17 +938,6 @@ static void phy_state_machine(struct work_struct *work)
if (err < 0) if (err < 0)
phy_error(phydev); phy_error(phydev);
mod_timer(&phydev->phy_timer, jiffies + PHY_STATE_TIME * HZ); schedule_delayed_work(&phydev->state_queue,
} 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);
} }

3
include/linux/phy.h
View file

@ -315,8 +315,7 @@ struct phy_device {
/* Interrupt and Polling infrastructure */ /* Interrupt and Polling infrastructure */
struct work_struct phy_queue; struct work_struct phy_queue;
struct work_struct state_queue; struct delayed_work state_queue;
struct timer_list phy_timer;
atomic_t irq_disable; atomic_t irq_disable;
struct mutex lock; struct mutex lock;