Re: [PATCH v4 2/2] livepatch: Convert timeouts to secs_to_jiffies()

[Petr Mladek <pmladek@suse.com>]

On Tue 2024-12-17 23:09:59, Easwar Hariharan wrote:
> Commit b35108a51cf7 ("jiffies: Define secs_to_jiffies()") introduced
> secs_to_jiffies(). As the value here is a multiple of 1000, use
> secs_to_jiffies() instead of msecs_to_jiffies to avoid the multiplication.
> 
> This is converted using scripts/coccinelle/misc/secs_to_jiffies.cocci with
> the following Coccinelle rules:
> 
> @@ constant C; @@
> 
> - msecs_to_jiffies(C * 1000)
> + secs_to_jiffies(C)
> 
> @@ constant C; @@
> 
> - msecs_to_jiffies(C * MSEC_PER_SEC)
> + secs_to_jiffies(C)
> 
> While here, replace the schedule_delayed_work() call with a 0 timeout
> with an immediate schedule_work() call.
> 
> --- a/samples/livepatch/livepatch-callbacks-busymod.c
> +++ b/samples/livepatch/livepatch-callbacks-busymod.c
> @@ -44,8 +44,7 @@ static void busymod_work_func(struct work_struct *work)
>  static int livepatch_callbacks_mod_init(void)
>  {
>  	pr_info("%s\n", __func__);
> -	schedule_delayed_work(&work,
> -		msecs_to_jiffies(1000 * 0));
> +	schedule_work(&work);

Is it safe to use schedule_work() for struct delayed_work?

It might work in theory but I do not feel comfortable with it.
Also I would expect a compiler warning.

If you really want to use schedule_work() then please
also define the structure with DECLARE_WORK()
and use cancel_work_sync() in livepatch_callbacks_mod_exit().

Best Regards,
Petr