Re: [PATCH v2] watchdog: core: Make use of devm_register_reboot_notifier()

[Andrey Smirnov]

On Sat, Apr 15, 2017 at 11:11 PM, Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
> On 04/11/2017 09:06 AM, Andrey Smirnov wrote:
>>
>> Save a bit of cleanup code by leveraging newly added
>> devm_register_reboot_notifier().
>>
>> Cc: cphealy@xxxxxxxxx
>> Cc: linux-kernel@xxxxxxxxxxxxxxx
>> Cc: Wim Van Sebroeck <wim@xxxxxxxxx>
>> Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
>> Cc: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
>> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
>> Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
>
>
> Acked-by: Guenter Roeck <linux@xxxxxxxxxxxx>
>

Andrew,

This patch can't go in via watchdog tree because it depends on
devm_register_reboot_notifier() which is still present only in
linux-next, any change you can pull this into linux-next as well?

Thanks,
Andrey Smirnov


>
>> ---
>>
>> Guenter, Andy:
>>
>> Here's the second version of the patch originally submitted in
>> [v1]. This time I tried to follow Guenter's suggestion of moving this
>> bit on initialization in watchdog_dev_register().
>>
>> If I missed something obvious why this patch wouldn't work, again,
>> please let me know.
>>
>> Patch introducting devm_register_reboot_notifier() can be found in
>> [other-patch]
>>
>> Thanks,
>> Andrey Smirnov
>>
>> [v1] https://lkml.org/lkml/2017/4/4/388
>> [other-patch] https://lkml.org/lkml/2017/3/20/671
>>
>>
>>  drivers/watchdog/watchdog_core.c | 35 -----------------------------------
>>  drivers/watchdog/watchdog_dev.c  | 32 ++++++++++++++++++++++++++++++++
>>  2 files changed, 32 insertions(+), 35 deletions(-)
>>
>> diff --git a/drivers/watchdog/watchdog_core.c
>> b/drivers/watchdog/watchdog_core.c
>> index 74265b2..8a8d952 100644
>> --- a/drivers/watchdog/watchdog_core.c
>> +++ b/drivers/watchdog/watchdog_core.c
>> @@ -137,25 +137,6 @@ int watchdog_init_timeout(struct watchdog_device
>> *wdd,
>>  }
>>  EXPORT_SYMBOL_GPL(watchdog_init_timeout);
>>
>> -static int watchdog_reboot_notifier(struct notifier_block *nb,
>> -                                   unsigned long code, void *data)
>> -{
>> -       struct watchdog_device *wdd = container_of(nb, struct
>> watchdog_device,
>> -                                                  reboot_nb);
>> -
>> -       if (code == SYS_DOWN || code == SYS_HALT) {
>> -               if (watchdog_active(wdd)) {
>> -                       int ret;
>> -
>> -                       ret = wdd->ops->stop(wdd);
>> -                       if (ret)
>> -                               return NOTIFY_BAD;
>> -               }
>> -       }
>> -
>> -       return NOTIFY_DONE;
>> -}
>> -
>>  static int watchdog_restart_notifier(struct notifier_block *nb,
>>                                      unsigned long action, void *data)
>>  {
>> @@ -244,19 +225,6 @@ static int __watchdog_register_device(struct
>> watchdog_device *wdd)
>>                 }
>>         }
>>
>> -       if (test_bit(WDOG_STOP_ON_REBOOT, &wdd->status)) {
>> -               wdd->reboot_nb.notifier_call = watchdog_reboot_notifier;
>> -
>> -               ret = register_reboot_notifier(&wdd->reboot_nb);
>> -               if (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;
>> -               }
>> -       }
>> -
>>         if (wdd->ops->restart) {
>>                 wdd->restart_nb.notifier_call = watchdog_restart_notifier;
>>
>> @@ -302,9 +270,6 @@ static void __watchdog_unregister_device(struct
>> watchdog_device *wdd)
>>         if (wdd->ops->restart)
>>                 unregister_restart_handler(&wdd->restart_nb);
>>
>> -       if (test_bit(WDOG_STOP_ON_REBOOT, &wdd->status))
>> -               unregister_reboot_notifier(&wdd->reboot_nb);
>> -
>>         watchdog_dev_unregister(wdd);
>>         ida_simple_remove(&watchdog_ida, wdd->id);
>>  }
>> diff --git a/drivers/watchdog/watchdog_dev.c
>> b/drivers/watchdog/watchdog_dev.c
>> index 32930a0..9a52990 100644
>> --- a/drivers/watchdog/watchdog_dev.c
>> +++ b/drivers/watchdog/watchdog_dev.c
>> @@ -42,6 +42,7 @@
>>  #include <linux/miscdevice.h>  /* For handling misc devices */
>>  #include <linux/module.h>      /* For module stuff/... */
>>  #include <linux/mutex.h>       /* For mutexes */
>> +#include <linux/reboot.h>      /* For reboot notifier */
>>  #include <linux/slab.h>                /* For memory functions */
>>  #include <linux/types.h>       /* For standard types (like size_t) */
>>  #include <linux/watchdog.h>    /* For watchdog specific items */
>> @@ -998,6 +999,25 @@ static struct class watchdog_class = {
>>         .dev_groups =   wdt_groups,
>>  };
>>
>> +static int watchdog_reboot_notifier(struct notifier_block *nb,
>> +                                   unsigned long code, void *data)
>> +{
>> +       struct watchdog_device *wdd = container_of(nb, struct
>> watchdog_device,
>> +                                                  reboot_nb);
>> +
>> +       if (code == SYS_DOWN || code == SYS_HALT) {
>> +               if (watchdog_active(wdd)) {
>> +                       int ret;
>> +
>> +                       ret = wdd->ops->stop(wdd);
>> +                       if (ret)
>> +                               return NOTIFY_BAD;
>> +               }
>> +       }
>> +
>> +       return NOTIFY_DONE;
>> +}
>> +
>>  /*
>>   *     watchdog_dev_register: register a watchdog device
>>   *     @wdd: watchdog device
>> @@ -1031,6 +1051,18 @@ int watchdog_dev_register(struct watchdog_device
>> *wdd)
>>         if (ret) {
>>                 device_destroy(&watchdog_class, devno);
>>                 watchdog_cdev_unregister(wdd);
>> +               return ret;
>> +       }
>> +
>> +       if (test_bit(WDOG_STOP_ON_REBOOT, &wdd->status)) {
>> +               wdd->reboot_nb.notifier_call = watchdog_reboot_notifier;
>> +
>> +               ret = devm_register_reboot_notifier(dev, &wdd->reboot_nb);
>> +               if (ret) {
>> +                       pr_err("watchdog%d: Cannot register reboot
>> notifier (%d)\n",
>> +                              wdd->id, ret);
>> +                       watchdog_dev_unregister(wdd);
>> +               }
>>         }
>>
>>         return ret;
>>
>