[patch 17/86] kernel.h: update comment about simple_strto() functions

Andrew Morton
2019-12-05T00:50:35Z

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Subject: kernel.h: update comment about simple_strto<foo>() functions

There were discussions in the past about use cases for simple_strto<foo>()
functions and, in some rare cases, they have a benefit over kstrto<foo>()
ones.

Update a comment to reduce confusion about special use cases.

Link: http://lkml.kernel.org/r/20190801192904.41087-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Suggested-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Mans Rullgard <mans@mansr.com>
Cc: Petr Mladek <pmladek@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

include/linux/kernel.h | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)

--- a/include/linux/kernel.h~kernelh-update-comment-about-simple_strtofoo-functions
+++ a/include/linux/kernel.h
@@ -348,8 +348,7 @@ int __must_check kstrtoll(const char *s,
* @res: Where to write the result of the conversion on success.
*
* Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
- * Used as a replacement for the obsolete simple_strtoull. Return code must
- * be checked.
+ * Used as a replacement for the simple_strtoull. Return code must be checked.
*/
static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
{
@@ -377,8 +376,7 @@ static inline int __must_check kstrtoul(
* @res: Where to write the result of the conversion on success.
*
* Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
- * Used as a replacement for the obsolete simple_strtoull. Return code must
- * be checked.
+ * Used as a replacement for the simple_strtoull. Return code must be checked.
*/
static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
{
@@ -454,7 +452,18 @@ static inline int __must_check kstrtos32
return kstrtoint_from_user(s, count, base, res);
}

-/* Obsolete, do not use. Use kstrto<foo> instead */
+/*
+ * Use kstrto<foo> instead.
+ *
+ * NOTE: simple_strto<foo> does not check for the range overflow and,
+ * depending on the input, may give interesting results.
+ *
+ * Use these functions if and only if you cannot use kstrto<foo>, because
+ * the conversion ends on the first non-digit character, which may be far
+ * beyond the supported range. It might be useful to parse the strings like
+ * 10x50 or 12:21 without altering original string or temporary buffer in use.
+ * Keep in mind above caveat.
+ */

extern unsigned long simple_strtoul(const char *,char **,unsigned int);
extern long simple_strtol(const char *,char **,unsigned int);
_