Re: [PATCH] mm: add printf attribute to shrinker_debugfs_name_alloc

[Qi Zheng]

Hi,

On 2023/10/10 08:50, Andrew Morton wrote:
> On Fri, 6 Oct 2023 22:30:51 +0200 Lucy Mielke <lucymielke@xxxxxxxxxx> wrote:
>
> > This fixes a compiler warning when compiling an allyesconfig with W=1:
> >
> > mm/internal.h:1235:9: error: function might be a candidate for ‘gnu_printf’
> > format attribute [-Werror=suggest-attribute=format]
>
> Thanks.  I added
>
> Fixes: c42d50aefd17 ("mm: shrinker: add infrastructure for dynamically allocating shrinker")
>
> to this.

Thanks.

> > --- a/mm/internal.h
> > +++ b/mm/internal.h
> > @@ -1229,8 +1229,8 @@ unsigned long shrink_slab(gfp_t gfp_mask, int nid, struct mem_cgroup *memcg,
> >   			  int priority);
> >   
> >   #ifdef CONFIG_SHRINKER_DEBUG
> > -static inline int shrinker_debugfs_name_alloc(struct shrinker *shrinker,
> > -					      const char *fmt, va_list ap)
> > +static inline __printf(2, 0) int shrinker_debugfs_name_alloc(
> > +			struct shrinker *shrinker, const char *fmt, va_list ap)
> >   {
> >   	shrinker->name = kvasprintf_const(GFP_KERNEL, fmt, ap);

And there is also a warning introduced by c42d50aefd17:

mm/shrinker.c: In function 'shrinker_alloc':
mm/shrinker.c:688:2: error: function 'shrinker_alloc' might be a 
candidate for 'gnu_printf' format attribute 
[-Werror=suggest-attribute=format]
  688 |  err = shrinker_debugfs_name_alloc(shrinker, fmt, ap);
      |  ^~~

This also needs to be fixed:

diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h
index e4f93120e0ab..1a00be90d93a 100644
--- a/include/linux/shrinker.h
+++ b/include/linux/shrinker.h
@@ -131,6 +131,7 @@ struct shrinker {
  */
 #define SHRINKER_NONSLAB       BIT(4)

+__printf(2, 3)
 struct shrinker *shrinker_alloc(unsigned int flags, const char *fmt, ...);
 void shrinker_register(struct shrinker *shrinker);
 void shrinker_free(struct shrinker *shrinker);

Other than that, LGTM.

Reviewed-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>

Thanks,
Qi

> >   
> > --
> > 2.42.0