Re: [PATCHv13,1/3] lib/string: add sysfs_match_string helper

From: Guenter Roeck
Date: Wed Dec 07 2016 - 18:54:53 EST


On Thu, Nov 24, 2016 at 02:21:42PM +0200, Heikki Krogerus wrote:
> Make a simple helper for matching strings with sysfs
> attribute files. In most parts the same as match_string(),
> except sysfs_match_string() uses sysfs_streq() instead of
> strcmp() for matching. This is more convenient when used
> with sysfs attributes.
>
> Signed-off-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> ---
> include/linux/string.h | 10 ++++++++++
> lib/string.c | 26 ++++++++++++++++++++++++++
> 2 files changed, 36 insertions(+)
>
> diff --git a/include/linux/string.h b/include/linux/string.h
> index 26b6f6a..c4011b2 100644
> --- a/include/linux/string.h
> +++ b/include/linux/string.h
> @@ -135,6 +135,16 @@ 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);
> +
> +/**
> + * sysfs_match_string - matches given string in an array
> + * @_a: array of strings
> + * @_s: string to match with
> + *
> + * Helper for __sysfs_match_string(). Calculates the size of @a automatically.
> + */
> +#define sysfs_match_string(_a, _s) __sysfs_match_string(_a, ARRAY_SIZE(_a), _s)
>
> #ifdef CONFIG_BINARY_PRINTF
> int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args);
> diff --git a/lib/string.c b/lib/string.c
> index ed83562..c7a20cb 100644
> --- a/lib/string.c
> +++ b/lib/string.c
> @@ -656,6 +656,32 @@ 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
> + * @array: array of strings
> + * @n: number of strings in the array or -1 for NULL terminated arrays
> + * @str: string to match with
> + *
> + * Returns index of @str in the @array or -EINVAL, just like match_string().
> + * Uses sysfs_streq instead of strcmp for matching.
> + */
> +int __sysfs_match_string(const char * const *array, size_t n, const char *str)
> +{
> + const char *item;
> + int index;
> +
> + for (index = 0; index < n; index++) {
> + item = array[index];
> + if (!item)
> + break;
> + if (!sysfs_streq(item, str))

No idea how this slipped in: sysfs_streq() returns true on a match,
meaning the "!" here is wrong.

Guenter

> + return index;
> + }
> +
> + return -EINVAL;
> +}
> +EXPORT_SYMBOL(__sysfs_match_string);
> +
> #ifndef __HAVE_ARCH_MEMSET
> /**
> * memset - Fill a region of memory with the given value