[PATCH] mm: add printf attribute to shrinker_debugfs_name_alloc

[PATCH] mm: add printf attribute to shrinker_debugfs_name_alloc

[Lucy Mielke]

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]

Signed-off-by: Lucy Mielke <lucymielke@icloud.com>
---
 mm/internal.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/internal.h b/mm/internal.h
index 18e360fa53bc..e23f1ea55a8e 100644
--- 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);
 
-- 
2.42.0

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

[Andrew Morton]

On Fri, 6 Oct 2023 22:30:51 +0200 Lucy Mielke <lucymielke@icloud.com> 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.

> --- 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);
>  
> -- 
> 2.42.0

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@icloud.com> 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@bytedance.com>

Thanks,
Qi

>>   
>> -- 
>> 2.42.0