lkml.org 
[lkml]   [2019]   [Jun]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH][V4] lib: fix __sysfs_match_string() helper when n != -1
On Tue, Jun 25, 2019 at 04:01:04PM +0300, Alexandru Ardelean wrote:
> The documentation the `__sysfs_match_string()` helper mentions that `n`
> (the size of the given array) should be:
> * @n: number of strings in the array or -1 for NULL terminated arrays
>
> The behavior of the function is different, in the sense that it exits on
> the first NULL element in the array.
>
> This patch changes the behavior, to exit the loop when a NULL element is
> found, and the size of the array is provided as -1.
>
> All current users of __sysfs_match_string() & sysfs_match_string() provide
> contiguous arrays of strings, so this behavior change doesn't influence
> anything (at this point in time).
>
> This behavior change allows for an array of strings to have NULL elements
> within the array, which will be ignored. This is particularly useful when
> creating mapping of strings and integers (as bitfields or other HW
> description).

Since it does nothing for current users and comes without an example,
it's hard to justify the need.

The code itself looks good to me.

>
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
> ---
>
> Changelog v3 -> v4:
> * split this patch away from series; there are some unsolved discussions
> that will probably need resolving per sub-system
>
> lib/string.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/lib/string.c b/lib/string.c
> index 3ab861c1a857..5bea3f98478a 100644
> --- a/lib/string.c
> +++ b/lib/string.c
> @@ -674,8 +674,11 @@ int __sysfs_match_string(const char * const *array, size_t n, const char *str)
>
> for (index = 0; index < n; index++) {
> item = array[index];
> - if (!item)
> + if (!item) {
> + if (n != (size_t)-1)
> + continue;
> break;
> + }
> if (sysfs_streq(item, str))
> return index;
> }
> --
> 2.20.1
>

--
With Best Regards,
Andy Shevchenko


\
 
 \ /
  Last update: 2019-06-25 15:28    [W:0.120 / U:0.236 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site