On Wed, Aug 29, 2018 at 09:42:38AM +0200, Wolfram Sang wrote:
> To prevent removing if NOWAYOUT, we invalidate the .remove function and
> suppress the bind/unbind attributes in sysfs. These are driver
> capabilities, so we need to set it up at runtime during init. To avoid
> boilerplate, introduce module_watchdog_driver() similar to
> module_driver(). On top of that, we then build
> module_watchdog_platform_driver(). Others may follow, if needed.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
> ---
> include/linux/watchdog.h | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
>
> diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h
> index 44985c4a1e86..c8ecbc53c807 100644
> --- a/include/linux/watchdog.h
> +++ b/include/linux/watchdog.h
> @@ -216,4 +216,21 @@ extern void watchdog_unregister_device(struct watchdog_device *);
> /* devres register variant */
> int devm_watchdog_register_device(struct device *dev, struct watchdog_device *);
>
> +#define module_watchdog_driver(__driver, __register, __unregister, __nowayout, ...) \
> +static int __init __driver##_init(void) \
> +{ \
> + __driver.driver.suppress_bind_attrs = !!(__nowayout); \
> + return __register(&(__driver) ##__VA_ARGS__); \
> +} \
Sorry, I'm not familiar w/ this level of detail of the driver interface.
Is the intent of the proposed changes to prevent the unload of
a module if it was loaded with the "nowayout" parameter?
If so, I thought the WD "nowayout" semantic was only supposed to be in effect
after /dev/watchdog was opened. The proposed change looks like it makes the
"nowayout" semantic take effect before /dev/watchdog is opened.
Thanks
> +module_init(__driver##_init); \
> +static void __exit __driver##_exit(void) \
> +{ \
> + __unregister(&(__driver), ##__VA_ARGS__); \
> +} \
> +module_exit(__driver##_exit)
> +
> +#define module_watchdog_platform_driver(__platform_driver, __nowayout) \
> + module_watchdog_driver(__platform_driver, platform_driver_register, \
> + platform_driver_unregister, __nowayout)
> +
> #endif /* ifndef _LINUX_WATCHDOG_H */
> --
> 2.11.0
--
-----------------------------------------------------------------------------
Jerry Hoemann Software Engineer Hewlett Packard Enterprise
-----------------------------------------------------------------------------
