Re: [PATCH 1/2] psi: Fix "no previous prototype" warnings when CONFIG_CGROUPS=n

[Johannes Weiner]

On Wed, Jan 19, 2022 at 02:39:39PM -0800, Suren Baghdasaryan wrote:
> When CONFIG_CGROUPS is disabled psi code generates the following warnings:
> 
> kernel/sched/psi.c:1112:21: warning: no previous prototype for 'psi_trigger_create' [-Wmissing-prototypes]
>     1112 | struct psi_trigger *psi_trigger_create(struct psi_group *group,
>          |                     ^~~~~~~~~~~~~~~~~~
> kernel/sched/psi.c:1182:6: warning: no previous prototype for 'psi_trigger_destroy' [-Wmissing-prototypes]
>     1182 | void psi_trigger_destroy(struct psi_trigger *t)
>          |      ^~~~~~~~~~~~~~~~~~~
> kernel/sched/psi.c:1249:10: warning: no previous prototype for 'psi_trigger_poll' [-Wmissing-prototypes]
>     1249 | __poll_t psi_trigger_poll(void **trigger_ptr,
>          |          ^~~~~~~~~~~~~~~~
> 
> Change declarations of these functions in the header to provide the
> prototypes even when they are unused.
>
> Fixes: 0e94682b73bf ("psi: introduce psi monitor")
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>

Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>

For a second I was confused by the "unused" in the changelog. The
functions themselves are used unconditionally: by the internal
/proc/pressure/* implementation. But I suppose that usage wouldn't
need the prototypes - hence unused prototypes.