Re: Stopping watchdog in watchdog driver remove functions

From	Guenter Roeck <linux@roeck-us.net>
Newsgroups	linux.kernel
Subject	Re: Stopping watchdog in watchdog driver remove functions
Date	2017-01-01 18:00 +0100
Message-ID	<sUREd-2NG-13@gated-at.bofh.it> (permalink)
References	<sUxPb-7ab-1@gated-at.bofh.it> <sUMlc-85I-9@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On 01/01/2017 03:14 AM, Wim Van Sebroeck wrote:
> Hi Guenter,
>
>> I noticed that several watchdog drivers stop the watchdog in trhe driver
>> remove function.
>> A non-exhaustive list of drivers doing that is
>>
>> 	drivers/watchdog/bcm7038_wdt.c
>> 	drivers/watchdog/cadence_wdt.c
>> 	drivers/watchdog/imgpdc_wdt.c
>> 	drivers/watchdog/jz4740_wdt.c
>> 	drivers/watchdog/kempld_wdt.c
>> 	drivers/watchdog/max77620_wdt.c
>> 	drivers/watchdog/moxart_wdt.c
>> 	drivers/watchdog/sama5d4_wdt.c
>> 	drivers/watchdog/tangox_wdt.c
>> 	drivers/watchdog/tegra_wdt.c
>>
>> Since a watchdog has to be closed for its driver to be removable, one
>> situation
>> where a watchdog is still running on unload is where the watchdog was
>> opened but
>> not closed properly (eg by killing the watchdog application, or if the
>> 'nowayout'
>> flag is set).
>>
>> Given that, does it even make sense to stop the watchdog in the remove
>> function ?
>> Should it even be permitted ?
>
>>From an API point of view: if WDIOF_MAGICCLOSE is being used then the watchdog
> _SHOULD_ continue to run when the watchdog was not properly closed (which
> normally also results in a reboot of the system).
> if WDIOF_MAGICCLOSE is not being used then closing the watchdog device means
> that the driver needs to stop the watchdog.
>
All the above have WDIOF_MAGICCLOSE set. Does that mean they should not stop
the watchdog on remove ?

Happy new year everyone !

Guenter

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Thread

Stopping watchdog in watchdog driver remove functions Guenter Roeck <linux@roeck-us.net> - 2016-12-31 20:50 +0100
  Re: Stopping watchdog in watchdog driver remove functions Wim Van Sebroeck <wim@iguana.be> - 2017-01-01 12:20 +0100
    Re: Stopping watchdog in watchdog driver remove functions Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-01-01 16:30 +0100
    Re: Stopping watchdog in watchdog driver remove functions Guenter Roeck <linux@roeck-us.net> - 2017-01-01 18:00 +0100

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