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Date: Fri, 6 Mar 2009 21:51:42 +0100
From: Marcin Slusarz <marcin.slusarz@...il.com>
To: netdev@...r.kernel.org
Cc: Andy Fleming <afleming@...escale.com>,
Trent Piepho <tpiepho@...escale.com>,
Jean Delvare <khali@...ux-fr.org>,
LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH] phylib: convert state_queue work to delayed_work
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@...il.com>
Cc: Andy Fleming <afleming@...escale.com>
Cc: Trent Piepho <tpiepho@...escale.com>
---
This patch was only compile tested.
---
drivers/net/phy/phy.c | 41 +++++++++++------------------------------
include/linux/phy.h | 3 +--
2 files changed, 12 insertions(+), 32 deletions(-)
diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index e4ede60..58b73b0 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -414,7 +414,6 @@ 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);
/**
* phy_start_machine - start PHY state machine tracking
@@ -434,11 +433,8 @@ 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;
- mod_timer(&phydev->phy_timer, jiffies + HZ);
+ INIT_DELAYED_WORK(&phydev->state_queue, phy_state_machine);
+ schedule_delayed_work(&phydev->state_queue, jiffies + HZ);
}
/**
@@ -451,8 +447,7 @@ 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);
+ cancel_delayed_work_sync(&phydev->state_queue);
mutex_lock(&phydev->lock);
if (phydev->state > PHY_UP)
@@ -680,11 +675,9 @@ static void phy_change(struct work_struct *work)
if (err)
goto irq_enable_err;
- /* Stop timer and run the state queue now. The work function for
- * state_queue will start the timer up again.
- */
- del_timer(&phydev->phy_timer);
- schedule_work(&phydev->state_queue);
+ /* reschedule state queue work to run as soon as possible */
+ cancel_delayed_work_sync(&phydev->state_queue);
+ schedule_delayed_work(&phydev->state_queue, 0);
return;
@@ -761,14 +754,13 @@ EXPORT_SYMBOL(phy_start);
/**
* 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 delayed_work *dwork =
+ container_of(work, struct delayed_work, work);
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 err = 0;
@@ -946,17 +938,6 @@ static void phy_state_machine(struct work_struct *work)
if (err < 0)
phy_error(phydev);
- 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);
+ schedule_delayed_work(&phydev->state_queue,
+ jiffies + PHY_STATE_TIME * HZ);
}
diff --git a/include/linux/phy.h b/include/linux/phy.h
index d7e54d9..32cf14a 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -315,8 +315,7 @@ struct phy_device {
/* Interrupt and Polling infrastructure */
struct work_struct phy_queue;
- struct work_struct state_queue;
- struct timer_list phy_timer;
+ struct delayed_work state_queue;
atomic_t irq_disable;
struct mutex lock;
--
1.6.0.6
--
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