[PATCH 3/3] watchdog: Drop pointer to watchdog device from struct watchdog_device

Guenter Roeck
2016-01-03T23:12:08Z

The lifetime of the watchdog device pointer is different from the lifetime
of its character device. Remove it entirely to avoid race conditions.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
Documentation/watchdog/watchdog-kernel-api.txt | 2 --
drivers/watchdog/watchdog_core.c | 8 ++++----
drivers/watchdog/watchdog_dev.c | 9 ++++-----
include/linux/watchdog.h | 2 --
4 files changed, 8 insertions(+), 13 deletions(-)

diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt
index 312f60009c3e..55120a055a14 100644
--- a/Documentation/watchdog/watchdog-kernel-api.txt
+++ b/Documentation/watchdog/watchdog-kernel-api.txt
@@ -44,7 +44,6 @@ The watchdog device structure looks like this:

struct watchdog_device {
int id;
- struct device *dev;
struct device *parent;
const struct attribute_group **groups;
const struct watchdog_info *info;
@@ -66,7 +65,6 @@ It contains following fields:
/dev/watchdog0 cdev (dynamic major, minor 0) as well as the old
/dev/watchdog miscdev. The id is set automatically when calling
watchdog_register_device.
-* dev: device under the watchdog class (created by watchdog_register_device).
* parent: set this to the parent device (or NULL) before calling
watchdog_register_device.
* groups: List of sysfs attribute groups to create when creating the watchdog
diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c
index ec1ab6c1a80b..e600fd93b7de 100644
--- a/drivers/watchdog/watchdog_core.c
+++ b/drivers/watchdog/watchdog_core.c
@@ -249,8 +249,8 @@ static int __watchdog_register_device(struct watchdog_device *wdd)

ret = register_reboot_notifier(&wdd->reboot_nb);
if (ret) {
- dev_err(wdd->dev, "Cannot register reboot notifier (%d)\n",
- ret);
+ pr_err("watchdog%d: Cannot register reboot notifier (%d)\n",
+ wdd->id, ret);
watchdog_dev_unregister(wdd);
ida_simple_remove(&watchdog_ida, wdd->id);
return ret;
@@ -262,8 +262,8 @@ static int __watchdog_register_device(struct watchdog_device *wdd)

ret = register_restart_handler(&wdd->restart_nb);
if (ret)
- dev_warn(wdd->dev, "Cannot register restart handler (%d)\n",
- ret);
+ pr_warn("watchog%d: Cannot register restart handler (%d)\n",
+ wdd->id, ret);
}

return 0;
diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index e89ccb2e9603..ba2ecce4aae6 100644
--- a/drivers/watchdog/watchdog_dev.c
+++ b/drivers/watchdog/watchdog_dev.c
@@ -143,7 +143,8 @@ static int watchdog_stop(struct watchdog_device *wdd)
return 0;

if (test_bit(WDOG_NO_WAY_OUT, &wdd->status)) {
- dev_info(wdd->dev, "nowayout prevents watchdog being stopped!\n");
+ pr_info("watchdog%d: nowayout prevents watchdog being stopped!\n",
+ wdd->id);
return -EBUSY;
}

@@ -604,7 +605,7 @@ static int watchdog_release(struct inode *inode, struct file *file)

/* If the watchdog was not stopped, send a keepalive ping */
if (err < 0) {
- dev_crit(wdd->dev, "watchdog did not stop!\n");
+ pr_crit("watchdog%d: watchdog did not stop!\n", wdd->id);
watchdog_ping(wdd);
}

@@ -751,7 +752,6 @@ int watchdog_dev_register(struct watchdog_device *wdd)
watchdog_cdev_unregister(wdd);
return PTR_ERR(dev);
}
- wdd->dev = dev;

return ret;
}
@@ -766,8 +766,7 @@ int watchdog_dev_register(struct watchdog_device *wdd)

void watchdog_dev_unregister(struct watchdog_device *wdd)
{
- device_destroy(&watchdog_class, wdd->dev->devt);
- wdd->dev = NULL;
+ device_destroy(&watchdog_class, wdd->wd_data->cdev.dev);
watchdog_cdev_unregister(wdd);
}

diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h
index 2a68370411a9..1fb11c5a49c6 100644
--- a/include/linux/watchdog.h
+++ b/include/linux/watchdog.h
@@ -55,7 +55,6 @@ struct watchdog_ops {
/** struct watchdog_device - The structure that defines a watchdog device
*
* @id: The watchdog's ID. (Allocated by watchdog_register_device)
- * @dev: The device for our watchdog
* @parent: The parent bus device
* @groups: List of sysfs attribute groups to create when creating the
* watchdog device.
@@ -84,7 +83,6 @@ struct watchdog_ops {
*/
struct watchdog_device {
int id;
- struct device *dev;
struct device *parent;
const struct attribute_group **groups;
const struct watchdog_info *info;
--
2.1.4