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SubjectRe: [PATCH] lib/string: update match_string() doc-strings with correct behavior
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On Wed, 2020-02-12 at 18:46 +0200, Andy Shevchenko wrote:
> [External]
>
> On Wed, Feb 12, 2020 at 04:47:23PM +0200, Alexandru Ardelean wrote:
> > There were a few attempts at changing behavior of the match_string()
> > helpers (i.e. 'match_string()' & 'sysfs_match_string()'), to change &
> > extend the behavior according to the doc-string.
> >
> > But the simplest approach is to just fix the doc-strings. The current
> > behavior is fine as-is, and some bugs were introduced trying to fix it.
> >
> > As for extending the behavior, new helpers can always be introduced if
> > needed.
> >
> > The match_string() helpers behave more like 'strncmp()' in the sense that
> > they go up to n elements or until the first NULL element in the array of
> > strings.
> >
> > This change updates the doc-strings with this info.
> >
> > Some references to the previous attempts (in no particular order):
> >
> > https://lore.kernel.org/lkml/20190508111913.7276-1-alexandru.ardelean@analog.com/
> >
> > https://lore.kernel.org/lkml/20190625130104.29904-1-alexandru.ardelean@analog.com/
> >
> > https://lore.kernel.org/lkml/20190422083257.21805-1-alexandru.ardelean@analog.com/
>
> ...
>
> > /**
> > * 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
> > + * @n: number of strings in the array to compare
>
> But this change won't be helpful, it actually hides the part of behaviour that
> is being used.
>
> > * @string: string to match with
> > *
> > + * This routine will look for a string in an array of strings up to the
> > + * n-th element in the array or until the first NULL element.
> > + *
>
> Perhaps this needs to be rephrased. Because now it has completely hidden the
> -1 case.

Hmm, it does make sense to specify the -1 behavior purely for historical
purposes.
Otheriwse, I don't feel it's that important to mention it, since you could
technically specify UINT_MAX [or similar] and get the same behavior.

>
> > * Return:
> > * index of a @string in the @array if matches, or %-EINVAL otherwise.
> > */
>
> Ditto for the second part.
>
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