The patch titled
Subject: lib/string.c: update match_string() doc-strings with correct behavior
has been added to the -mm tree. Its filename is
lib-string-update-match_string-doc-strings-with-correct-behavior.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/lib-string-update-match_string-doc-strings-with-correct-behavior.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/lib-string-update-match_string-doc-strings-with-correct-behavior.patch
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------------------------------------------------------
From: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>
Subject: lib/string.c: update match_string() doc-strings with correct behavior
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.
Link: http://lkml.kernel.org/r/20200213072722.8249-1-alexandru.ardelean@xxxxxxxxxx
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>
Acked-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: "Tobin C . Harding" <tobin@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/string.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
--- a/lib/string.c~lib-string-update-match_string-doc-strings-with-correct-behavior
+++ a/lib/string.c
@@ -699,6 +699,14 @@ EXPORT_SYMBOL(sysfs_streq);
* @n: number of strings in the array or -1 for NULL terminated arrays
* @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.
+ *
+ * Historically the value of -1 for @n, was used to search in arrays that
+ * are NULL terminated. However, the function does not make a distinction
+ * when finishing the search: either @n elements have been compared OR
+ * the first NULL element was found.
+ *
* Return:
* index of a @string in the @array if matches, or %-EINVAL otherwise.
*/
@@ -727,6 +735,14 @@ EXPORT_SYMBOL(match_string);
*
* Returns index of @str in the @array or -EINVAL, just like match_string().
* Uses sysfs_streq instead of strcmp for matching.
+ *
+ * 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.
+ *
+ * Historically the value of -1 for @n, was used to search in arrays that
+ * are NULL terminated. However, the function does not make a distinction
+ * when finishing the search: either @n elements have been compared OR
+ * the first NULL element was found.
*/
int __sysfs_match_string(const char * const *array, size_t n, const char *str)
{
_
Patches currently in -mm which might be from alexandru.ardelean@xxxxxxxxxx are
lib-string-update-match_string-doc-strings-with-correct-behavior.patch
