Make the WDT driver fully preemptible.
This is required in order to apply a locking fix to retu_write_reg.
It also improves power management by using round_relative_jiffies().
Signed-off-by: Michael Buesch <mb@xxxxxxxxx>
---
Tony, thanks for the report on this issue.
You may apply the locking fix on to of this.
Index: linux-2.6.38-rc6/drivers/cbus/retu-wdt.c
===================================================================
--- linux-2.6.38-rc6.orig/drivers/cbus/retu-wdt.c 2011-03-02 16:08:59.022211654 +0100
+++ linux-2.6.38-rc6/drivers/cbus/retu-wdt.c 2011-03-02 16:29:43.215284501 +0100
@@ -58,13 +58,11 @@ struct retu_wdt_dev {
struct device *dev;
int users;
struct miscdevice retu_wdt_miscdev;
- struct timer_list ping_timer;
+ struct delayed_work ping_work;
};
static struct retu_wdt_dev *retu_wdt;
-static void retu_wdt_set_ping_timer(unsigned long enable);
-
static int _retu_modify_counter(unsigned int new)
{
if (retu_wdt)
@@ -86,6 +84,31 @@ static int retu_modify_counter(unsigned
return 0;
}
+/*
+ * Since retu watchdog cannot be disabled in hardware, we must kick it
+ * with a timer until userspace watchdog software takes over. Do this
+ * unless /dev/watchdog is open or CONFIG_WATCHDOG_NOWAYOUT is set.
+ */
+static void retu_wdt_ping_enable(struct retu_wdt_dev *wdev)
+{
+ _retu_modify_counter(RETU_WDT_MAX_TIMER);
+ schedule_delayed_work(&wdev->ping_work,
+ round_jiffies_relative(RETU_WDT_DEFAULT_TIMER * HZ));
+}
+
+static void retu_wdt_ping_disable(struct retu_wdt_dev *wdev)
+{
+ _retu_modify_counter(RETU_WDT_MAX_TIMER);
+ cancel_delayed_work_sync(&wdev->ping_work);
+}
+
+static void retu_wdt_ping_work(struct work_struct *work)
+{
+ struct retu_wdt_dev *wdev = container_of(to_delayed_work(work),
+ struct retu_wdt_dev, ping_work);
+ retu_wdt_ping_enable(wdev);
+}
+
static ssize_t retu_wdt_period_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -105,7 +128,7 @@ static ssize_t retu_wdt_period_store(str
int ret;
#ifdef CONFIG_WATCHDOG_NOWAYOUT
- retu_wdt_set_ping_timer(0);
+ retu_wdt_ping_disable(retu_wdt);
#endif
if (sscanf(buf, "%u", &new_period) != 1) {
@@ -136,30 +159,13 @@ static DEVICE_ATTR(period, S_IRUGO | S_I
retu_wdt_period_store);
static DEVICE_ATTR(counter, S_IRUGO, retu_wdt_counter_show, NULL);
-/*----------------------------------------------------------------------------*/
-
-/*
- * Since retu watchdog cannot be disabled in hardware, we must kick it
- * with a timer until userspace watchdog software takes over. Do this
- * unless /dev/watchdog is open or CONFIG_WATCHDOG_NOWAYOUT is set.
- */
-static void retu_wdt_set_ping_timer(unsigned long enable)
-{
- _retu_modify_counter(RETU_WDT_MAX_TIMER);
- if (enable)
- mod_timer(&retu_wdt->ping_timer,
- jiffies + RETU_WDT_DEFAULT_TIMER * HZ);
- else
- del_timer_sync(&retu_wdt->ping_timer);
-}
-
static int retu_wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(1, (unsigned long *)&(retu_wdt->users)))
return -EBUSY;
file->private_data = (void *)retu_wdt;
- retu_wdt_set_ping_timer(0);
+ retu_wdt_ping_disable(retu_wdt);
return nonseekable_open(inode, file);
}
@@ -169,7 +175,7 @@ static int retu_wdt_release(struct inode
struct retu_wdt_dev *wdev = file->private_data;
#ifndef CONFIG_WATCHDOG_NOWAYOUT
- retu_wdt_set_ping_timer(1);
+ retu_wdt_ping_enable(retu_wdt);
#endif
wdev->users = 0;
@@ -232,7 +238,7 @@ static int __devinit retu_wdt_ping(void)
#ifdef CONFIG_WATCHDOG_NOWAYOUT
retu_modify_counter(RETU_WDT_MAX_TIMER);
#else
- retu_wdt_set_ping_timer(1);
+ retu_wdt_ping_enable(retu_wdt);
#endif
return 0;
@@ -283,7 +289,7 @@ static int __init retu_wdt_probe(struct
if (ret)
goto free3;
- setup_timer(&wdev->ping_timer, retu_wdt_set_ping_timer, 1);
+ INIT_DELAYED_WORK(&wdev->ping_work, retu_wdt_ping_work);
/* passed as module parameter? */
ret = retu_modify_counter(counter_param);
@@ -326,6 +332,7 @@ static int __devexit retu_wdt_remove(str
misc_deregister(&wdev->retu_wdt_miscdev);
device_remove_file(&pdev->dev, &dev_attr_period);
device_remove_file(&pdev->dev, &dev_attr_counter);
+ cancel_delayed_work_sync(&wdev->ping_work);
kfree(wdev);
return 0;
--
Greetings, Michael.
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