If a daemon has /dev/watchdog open, and exits (say by crashing or
sigkill), watchdog_release() generates a new watchdog_ping(), extending
the life of the machine. However, the daemon may require control over
whether or not the watchdog is pinged, and the ping generated by close
compromises this control.
Signed-off-by: David Teigland <teigland@xxxxxxxxxx>
---
drivers/watchdog/watchdog_dev.c | 7 ++++++-
include/linux/watchdog.h | 2 ++
2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index ef8edec..47ae7fe 100644
--- a/drivers/watchdog/watchdog_dev.c
+++ b/drivers/watchdog/watchdog_dev.c
@@ -394,6 +394,9 @@ static long watchdog_ioctl(struct file *file, unsigned int cmd,
if (err)
return err;
return put_user(val, p);
+ case WDIOC_NOCLOSEPING:
+ set_bit(WDOG_NO_CLOSE_PING, &wdd->status);
+ return 0;
default:
return -ENOTTY;
}
@@ -480,7 +483,9 @@ static int watchdog_release(struct inode *inode, struct file *file)
if (!test_bit(WDOG_UNREGISTERED, &wdd->status))
dev_crit(wdd->dev, "watchdog did not stop!\n");
mutex_unlock(&wdd->lock);
- watchdog_ping(wdd);
+
+ if (!test_bit(WDOG_NO_CLOSE_PING, &wdd->status))
+ watchdog_ping(wdd);
}
/* Allow the owner module to be unloaded again */
diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h
index da70f0f..4fa10ff 100644
--- a/include/linux/watchdog.h
+++ b/include/linux/watchdog.h
@@ -31,6 +31,7 @@ struct watchdog_info {
#define WDIOC_SETPRETIMEOUT _IOWR(WATCHDOG_IOCTL_BASE, 8, int)
#define WDIOC_GETPRETIMEOUT _IOR(WATCHDOG_IOCTL_BASE, 9, int)
#define WDIOC_GETTIMELEFT _IOR(WATCHDOG_IOCTL_BASE, 10, int)
+#define WDIOC_NOCLOSEPING _IOR(WATCHDOG_IOCTL_BASE, 11, int)
#define WDIOF_UNKNOWN -1 /* Unknown flag error */
#define WDIOS_UNKNOWN -1 /* Unknown status error */
@@ -140,6 +141,7 @@ struct watchdog_device {
#define WDOG_ALLOW_RELEASE 2 /* Did we receive the magic char ? */
#define WDOG_NO_WAY_OUT 3 /* Is 'nowayout' feature set ? */
#define WDOG_UNREGISTERED 4 /* Has the device been unregistered */
+#define WDOG_NO_CLOSE_PING 5 /* Do not ping in watchdog_release() */
};
#ifdef CONFIG_WATCHDOG_NOWAYOUT
--
1.7.10.1.362.g242cab3
--
To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
