Re: [PATCH] powerpc/watchdog: Convert timers to use timer_setup()

From: Michael Ellerman
Date: Mon Oct 16 2017 - 23:49:37 EST


Kees Cook <keescook@xxxxxxxxxxxx> writes:

> In preparation for unconditionally passing the struct timer_list pointer to
> all timer callbacks, switch to using the new timer_setup() and from_timer()
> to pass the timer pointer explicitly.
>
> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> Cc: Paul Mackerras <paulus@xxxxxxxxx>
> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
> Cc: linuxppc-dev@xxxxxxxxxxxxxxxx
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> ---
> arch/powerpc/kernel/watchdog.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/arch/powerpc/kernel/watchdog.c b/arch/powerpc/kernel/watchdog.c
> index 15e209a37c2d..50797528b5e1 100644
> --- a/arch/powerpc/kernel/watchdog.c
> +++ b/arch/powerpc/kernel/watchdog.c
> @@ -263,9 +263,8 @@ static void wd_timer_reset(unsigned int cpu, struct timer_list *t)
> add_timer_on(t, cpu);
> }
>
> -static void wd_timer_fn(unsigned long data)
> +static void wd_timer_fn(struct timer_list *t)

At first glance this looks like it will break, changing the signature,
but the new timer_setup() force-casts to the old signature (for now),
and we can fit a pointer in an unsigned long so it's OK.

> {
> - struct timer_list *t = this_cpu_ptr(&wd_timer);
> int cpu = smp_processor_id();
>
> watchdog_timer_interrupt(cpu);
> @@ -292,7 +291,7 @@ static void start_watchdog_timer_on(unsigned int cpu)
>
> per_cpu(wd_timer_tb, cpu) = get_tb();
>
> - setup_pinned_timer(t, wd_timer_fn, 0);
> + timer_setup(t, wd_timer_fn, TIMER_PINNED);
> wd_timer_reset(cpu, t);
> }
>

Acked-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>

cheers