[PATCH 1/6] lib: string: add function strtolower()

[Jani Nikula]

On Fri, 01 Jul 2016, Markus Mayer <mmayer at broadcom.com> wrote:
> Add a function called strtolower() to convert strings to lower case
> in-place, overwriting the original string.
>
> This seems to be a recurring requirement in the kernel that is
> currently being solved by several duplicated implementations doing the
> same thing.
>
> Signed-off-by: Markus Mayer <mmayer at broadcom.com>
> ---
>  include/linux/string.h |  1 +
>  lib/string.c           | 14 ++++++++++++++
>  2 files changed, 15 insertions(+)
>
> diff --git a/include/linux/string.h b/include/linux/string.h
> index 26b6f6a..aad605e 100644
> --- a/include/linux/string.h
> +++ b/include/linux/string.h
> @@ -116,6 +116,7 @@ extern void * memchr(const void *,int,__kernel_size_t);
>  #endif
>  void *memchr_inv(const void *s, int c, size_t n);
>  char *strreplace(char *s, char old, char new);
> +char *strtolower(char *s);
>  
>  extern void kfree_const(const void *x);
>  
> diff --git a/lib/string.c b/lib/string.c
> index ed83562..6e3b560 100644
> --- a/lib/string.c
> +++ b/lib/string.c
> @@ -952,3 +952,17 @@ char *strreplace(char *s, char old, char new)
>  	return s;
>  }
>  EXPORT_SYMBOL(strreplace);
> +

This needs a kernel-doc comment right here.

> +char *strtolower(char *s)
> +{
> +	char *p;
> +
> +        if (unlikely(!s))
> +                return NULL;

Using spaces for indentation? See scripts/checkpatch.pl.

> +
> +	for (p = s; *p; p++)
> +		*p = tolower(*p);
> +
> +	return s;

Why does it return a value? Could be void?

BR,
Jani.

> +}
> +EXPORT_SYMBOL(strtolower);

-- 
Jani Nikula, Intel Open Source Technology Center