Re: repeat a function after fixed time period

[Arjan van de Ven <arjan@infradead.org>]

> 
> This kernel code should do just fine.
> 
> 
> 
> struct INFO {
>      struct timer_list timer;            // For test timer
>      atomic_t running;                   // Timer is running
>      };
> 
> //-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> //
> //   This stops the timer. This must NOT be called with a spin-lock
> //   held.
> //
> static void stop_timer()
> {
>      if(atomic_read(&info->running))
>      {
>          atomic_dec(&info->running);

this is a race.

>          if(info->timer.function)
>              del_timer(&info->timer);

you probably want del_timer_sync() here.


> static void start_timer(void)
> {
>      if(!atomic_read(&info->running))
>      {
>          atomic_inc(&info->running);

same race.


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