linux-kernel - Re: [PATCH 2/2] lib: call native hex_to_bin() inside

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Message-ID: <CACVxJT-0=cpieN52g2LZ1W+PPmpL-kR9nHCk53bBSR=Js1cbRA@mail.gmail.com>
Date:	Mon, 18 Jul 2011 13:31:18 +0300
From:	Alexey Dobriyan <adobriyan@...il.com>
To:	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:	linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH 2/2] lib: call native hex_to_bin() inside _kstrtoull()

On Mon, Jul 18, 2011 at 11:23 AM, Andy Shevchenko
<andriy.shevchenko@...ux.intel.com> wrote:
> --- a/lib/kstrtox.c
> +++ b/lib/kstrtox.c
> @@ -39,25 +39,18 @@ static int _kstrtoull(const char *s, unsigned int base, unsigned long long *res)
>        acc = 0;
>        ok = 0;
>        while (*s) {
> -               unsigned int val;
> +               int val;
>
> -               if ('0' <= *s && *s <= '9')
> -                       val = *s - '0';
> -               else if ('a' <= TOLOWER(*s) && TOLOWER(*s) <= 'f')
> -                       val = TOLOWER(*s) - 'a' + 10;
> -               else if (*s == '\n' && *(s + 1) == '\0')
> +               if (unlikely(*s == '\n' && *(s + 1) == '\0'))
>                        break;
> -               else
> -                       return -EINVAL;
>
> -               if (val >= base)
> +               val = hex_to_bin(*s++);
> +               if (val >= base || val < 0)
>                        return -EINVAL;
>                if (acc > div_u64(ULLONG_MAX - val, base))
>                        return -ERANGE;
>                acc = acc * base + val;
>                ok = 1;
> -
> -               s++;
>        }
>        if (!ok)
>                return -EINVAL;

1. unlikely() and s++ move don't have anything to do with changes
2. I don't understand desire to use some half-thought out API,
   in fact, restricting to radix 16 is arbitrary.
   Without such restriction hex_to_bin doesn't make sense.
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