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| author | Sebastian Reichel <sebastian.reichel@collabora.co.uk> | 2017-05-12 14:05:32 +0200 |
|---|---|---|
| committer | Wim Van Sebroeck <wim@iguana.be> | 2017-06-05 20:55:17 +0200 |
| commit | 2501b015313fe2fa40ed11fa4dd1748e09b7c773 (patch) | |
| tree | 4765eaf1722ba0445ed73ad0462752c260beb551 | |
| parent | 166fbcf88fdafa02f784ec25ac64745c716b2de0 (diff) | |
| download | lwn-2501b015313fe2fa40ed11fa4dd1748e09b7c773.tar.gz lwn-2501b015313fe2fa40ed11fa4dd1748e09b7c773.zip | |
watchdog: core: add option to avoid early handling of watchdog
On some systems its desirable to have watchdog reboot the system
when it does not come up fast enough. This adds a kernel parameter
to disable the auto-update of watchdog before userspace takes over
and a kernel option to set the default. The info messages were
added to shorten error searching on misconfigured systems.
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
| -rw-r--r-- | drivers/watchdog/Kconfig | 11 | ||||
| -rw-r--r-- | drivers/watchdog/watchdog_dev.c | 19 |
2 files changed, 27 insertions, 3 deletions
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index 2696493c808b..e9da19627914 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -46,6 +46,17 @@ config WATCHDOG_NOWAYOUT get killed. If you say Y here, the watchdog cannot be stopped once it has been started. +config WATCHDOG_HANDLE_BOOT_ENABLED + bool "Update boot-enabled watchdog until userspace takes over" + default y + help + The default watchdog behaviour (which you get if you say Y here) is + to ping watchdog devices that were enabled before the driver has + been loaded until control is taken over from userspace using the + /dev/watchdog file. If you say N here, the kernel will not update + the watchdog on its own. Thus if your userspace does not start fast + enough your device will reboot. + config WATCHDOG_SYSFS bool "Read different watchdog information through sysfs" help diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c index d5d2bbd8f428..4bc7ab60b12c 100644 --- a/drivers/watchdog/watchdog_dev.c +++ b/drivers/watchdog/watchdog_dev.c @@ -80,6 +80,9 @@ static struct watchdog_core_data *old_wd_data; static struct workqueue_struct *watchdog_wq; +static bool handle_boot_enabled = + IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED); + static inline bool watchdog_need_worker(struct watchdog_device *wdd) { /* All variables in milli-seconds */ @@ -956,9 +959,14 @@ static int watchdog_cdev_register(struct watchdog_device *wdd, dev_t devno) * and schedule an immediate ping. */ if (watchdog_hw_running(wdd)) { - __module_get(wdd->ops->owner); - kref_get(&wd_data->kref); - queue_delayed_work(watchdog_wq, &wd_data->work, 0); + if (handle_boot_enabled) { + __module_get(wdd->ops->owner); + kref_get(&wd_data->kref); + queue_delayed_work(watchdog_wq, &wd_data->work, 0); + } else { + pr_info("watchdog%d running and kernel based pre-userspace handler disabled\n", + wdd->id); + } } return 0; @@ -1106,3 +1114,8 @@ void __exit watchdog_dev_exit(void) class_unregister(&watchdog_class); destroy_workqueue(watchdog_wq); } + +module_param(handle_boot_enabled, bool, 0444); +MODULE_PARM_DESC(handle_boot_enabled, + "Watchdog core auto-updates boot enabled watchdogs before userspace takes over (default=" + __MODULE_STRING(IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED)) ")"); |