Re: [PATCH 1/2] lib: add __sysfs_match_string_with_gaps() helper

Jonathan Cameron
2019-04-22T10:37:46Z

On Mon, 22 Apr 2019 11:32:56 +0300
Alexandru Ardelean <alexandru.ardelean@analog.com> wrote:

> This helper is similar to __sysfs_match_string() with the exception that it
> ignores NULL elements within the array.
> It takes an extra parameter (called `gaps`) which when true will ignore
> the NULL elements. When false, this function behaves exactly like
> `__sysfs_match_string()`.
>
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>

Hi Alex,

The existence of that gaps parameter does seem a little odd.
Why not just have the exposed _gaps form wrap a version that
takes that parameter and always set it to true?

Otherwise looks good to me.

Jonathan

> ---
> include/linux/string.h | 9 ++++++++-
> lib/string.c | 14 ++++++++++----
> 2 files changed, 18 insertions(+), 5 deletions(-)
>
> diff --git a/include/linux/string.h b/include/linux/string.h
> index 7927b875f80c..30595ed483dc 100644
> --- a/include/linux/string.h
> +++ b/include/linux/string.h
> @@ -189,7 +189,14 @@ static inline int strtobool(const char *s, bool *res)
> }
>
> int match_string(const char * const *array, size_t n, const char *string);
> -int __sysfs_match_string(const char * const *array, size_t n, const char *s);
> +int __sysfs_match_string_with_gaps(const char * const *array, size_t n,
> + const char *str, bool gaps);
> +
> +static inline int __sysfs_match_string(const char * const *array, size_t n,
> + const char *str)
> +{
> + return __sysfs_match_string_with_gaps(array, n, str, false);
> +}
>
> /**
> * sysfs_match_string - matches given string in an array
> diff --git a/lib/string.c b/lib/string.c
> index 38e4ca08e757..8ddac3cd292a 100644
> --- a/lib/string.c
> +++ b/lib/string.c
> @@ -659,30 +659,36 @@ int match_string(const char * const *array, size_t n, const char *string)
> EXPORT_SYMBOL(match_string);
>
> /**
> - * __sysfs_match_string - matches given string in an array
> + * __sysfs_match_string_with_gaps - matches string in array ignoring NULLs
> * @array: array of strings
> * @n: number of strings in the array or -1 for NULL terminated arrays
> * @str: string to match with
> + * @gaps: boolean to ignore NULL elements within the array
> *
> * Returns index of @str in the @array or -EINVAL, just like match_string().
> * Uses sysfs_streq instead of strcmp for matching.
> + * Ignores NULL pointers within the @array if @gaps is true.
> */
> -int __sysfs_match_string(const char * const *array, size_t n, const char *str)
> +int __sysfs_match_string_with_gaps(const char * const *array, size_t n,
> + const char *str, bool gaps)
> {
> const char *item;
> int index;
>
> for (index = 0; index < n; index++) {
> item = array[index];
> - if (!item)
> + if (!item) {
> + if (gaps)
> + continue;
> break;
> + }
> if (sysfs_streq(item, str))
> return index;
> }
>
> return -EINVAL;
> }
> -EXPORT_SYMBOL(__sysfs_match_string);
> +EXPORT_SYMBOL(__sysfs_match_string_with_gaps);
>
> #ifndef __HAVE_ARCH_MEMSET
> /**