2023-10-06 20:38:18

by Lucy Mielke

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

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 <[email protected]>
---
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

2023-10-10 00:50:34

by Andrew Morton

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

On Fri, 6 Oct 2023 22:30:51 +0200 Lucy Mielke <[email protected]> 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

2023-10-10 02:26:55

by Qi Zheng

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

Hi,

On 2023/10/10 08:50, Andrew Morton wrote:
> On Fri, 6 Oct 2023 22:30:51 +0200 Lucy Mielke <[email protected]> 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 <[email protected]>

Thanks,
Qi

>>
>> --
>> 2.42.0