On Thu, 9 Apr 2015 18:26:14 +0300 Alexey Dobriyan <adobri...@gmail.com> wrote:

> kstrto*() and kstrto*_from_user() family of functions were added
> help with parsing one integer written as string to proc/sysfs/debugfs
> files and pass it elsewhere. But they have a limitation: string passed
> must end with \0 or \n\0. There are enough places where kstrto*()
> functions can't be used because of this limitation. Trivial example:
> parse "%u.%u".
> 
> ...
>
>  include/linux/kernel.h |   72 +++++++++++++++++++
>  lib/Makefile           |    1 
>  lib/kstrtox.c          |   27 +------
>  lib/parse-integer.c    |  180 
> +++++++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 257 insertions(+), 23 deletions(-)

That's a lot of code for something which is almost the same as
kstrtofoo().

Can we hack up _kstrtoull() to optionally provide the new behaviour?
We could use the top bit of `base' to select the behaviour.  Something
like

--- a/lib/kstrtox.c~a
+++ a/lib/kstrtox.c
@@ -87,19 +87,23 @@ static int _kstrtoull(const char *s, uns
 {
        unsigned long long _res;
        unsigned int rv;
+       const char *cursor;
+       const unsigned int __base = base & 0x7fffffff;
 
-       s = _parse_integer_fixup_radix(s, &base);
-       rv = _parse_integer(s, base, &_res);
+       cursor = _parse_integer_fixup_radix(s, &__base);
+       rv = _parse_integer(cursor, __base, &_res);
        if (rv & KSTRTOX_OVERFLOW)
                return -ERANGE;
        if (rv == 0)
                return -EINVAL;
-       s += rv;
-       if (*s == '\n')
-               s++;
-       if (*s)
-               return -EINVAL;
+       cursor += rv;
        *res = _res;
+       if (base & 0x80000000)
+               return cursor - s;
+       if (*cursor == '\n')
+               cursor++;
+       if (*cursor)
+               return -EINVAL;
        return 0;
 }
 
then add a bunch of wrappers?
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