From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxx Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> Suggested-by: Miguel Ojeda <miguel.ojeda.sandonis@xxxxxxxxx> Cc: Geert Uytterhoeven <geert+renesas@xxxxxxxxx> Cc: Mans Rullgard <mans@xxxxxxxxx> Cc: Petr Mladek <pmladek@xxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- 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); _
