[PATCH v1 1/1] string: Introduce __free(kfree_const)

[PATCH v1 1/1] string: Introduce __free(kfree_const)

[Andy Shevchenko]

__free(kfree_const) may be used in the cases when one part of the code
relies on the constant string literals, while the other uses a heap
(via kasprintf(), for example).

Requested-by: Chen-Yu Tsai <wenst@chromium.org>
Link: https://lore.kernel.org/r/CAGXv+5HGZwAKpGpyV4=QHfg7yBQPx-syc1Gma2qad_tzW_RLog@mail.gmail.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 include/linux/string.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/linux/string.h b/include/linux/string.h
index 75bfc194ad20..6f3501b56c11 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -294,8 +294,11 @@ static inline bool mem_is_zero(const void *s, size_t n)
 	return !memchr_inv(s, 0, n);
 }
 
+/* mm/util.c */
 extern void kfree_const(const void *x);
 
+DEFINE_FREE(kfree_const, void *, if (!IS_ERR_OR_NULL(_T)) kfree_const(_T))
+
 extern char *kstrdup(const char *s, gfp_t gfp) __malloc;
 extern const char *kstrdup_const(const char *s, gfp_t gfp);
 extern char *kstrndup(const char *s, size_t len, gfp_t gfp);
-- 
2.50.1

Re: [PATCH v1 1/1] string: Introduce __free(kfree_const)

[Chen-Yu Tsai]

On Tue, Aug 11, 2026 at 3:13 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> __free(kfree_const) may be used in the cases when one part of the code
> relies on the constant string literals, while the other uses a heap
> (via kasprintf(), for example).
>
> Requested-by: Chen-Yu Tsai <wenst@chromium.org>
> Link: https://lore.kernel.org/r/CAGXv+5HGZwAKpGpyV4=QHfg7yBQPx-syc1Gma2qad_tzW_RLog@mail.gmail.com
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>  include/linux/string.h | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/include/linux/string.h b/include/linux/string.h
> index 75bfc194ad20..6f3501b56c11 100644
> --- a/include/linux/string.h
> +++ b/include/linux/string.h
> @@ -294,8 +294,11 @@ static inline bool mem_is_zero(const void *s, size_t n)
>         return !memchr_inv(s, 0, n);
>  }
>
> +/* mm/util.c */
>  extern void kfree_const(const void *x);
>
> +DEFINE_FREE(kfree_const, void *, if (!IS_ERR_OR_NULL(_T)) kfree_const(_T))
> +

Matches what we already have for kfree(), so

Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>

>  extern char *kstrdup(const char *s, gfp_t gfp) __malloc;
>  extern const char *kstrdup_const(const char *s, gfp_t gfp);
>  extern char *kstrndup(const char *s, size_t len, gfp_t gfp);
> --
> 2.50.1
>

Re: [PATCH v1 1/1] string: Introduce __free(kfree_const)

[Andy Shevchenko]

On Tue, Aug 11, 2026 at 06:42:51PM +0800, Chen-Yu Tsai wrote:
> On Tue, Aug 11, 2026 at 3:13 PM Andy Shevchenko
> <andriy.shevchenko@linux.intel.com> wrote:

> Matches what we already have for kfree(), so
> 
> Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>

Thanks!

I think you can incorporate this to (will be) your mini-series. But let's hear
from Kees and others if he is okay with the idea.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v1 1/1] string: Introduce __free(kfree_const)

[Chen-Yu Tsai]

On Tue, Aug 11, 2026 at 6:53 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> On Tue, Aug 11, 2026 at 06:42:51PM +0800, Chen-Yu Tsai wrote:
> > On Tue, Aug 11, 2026 at 3:13 PM Andy Shevchenko
> > <andriy.shevchenko@linux.intel.com> wrote:
>
> > Matches what we already have for kfree(), so
> >
> > Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>
>
> Thanks!
>
> I think you can incorporate this to (will be) your mini-series. But let's hear
> from Kees and others if he is okay with the idea.

If folks can merge it for the next cycle that would be even better.
My series already has three cross-tree build dependencies...


ChenYu

Re: [PATCH v1 1/1] string: Introduce __free(kfree_const)

[Chen-Yu Tsai]

On Tue, Aug 11, 2026 at 6:58 PM Chen-Yu Tsai <wenst@chromium.org> wrote:
>
> On Tue, Aug 11, 2026 at 6:53 PM Andy Shevchenko
> <andriy.shevchenko@linux.intel.com> wrote:
> >
> > On Tue, Aug 11, 2026 at 06:42:51PM +0800, Chen-Yu Tsai wrote:
> > > On Tue, Aug 11, 2026 at 3:13 PM Andy Shevchenko
> > > <andriy.shevchenko@linux.intel.com> wrote:
> >
> > > Matches what we already have for kfree(), so
> > >
> > > Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>
> >
> > Thanks!
> >
> > I think you can incorporate this to (will be) your mini-series. But let's hear
> > from Kees and others if he is okay with the idea.
>
> If folks can merge it for the next cycle that would be even better.
> My series already has three cross-tree build dependencies...

Ah, no, I got it confused with my other stuff in-flight. This one is easy.

Anyway, will wait for others to respond.