Re: [PATCHv2] fat: don't use custom hex_to_bin()

From: Andy Shevchenko
Date: Thu Sep 29 2011 - 09:07:52 EST


On Wed, 2011-09-28 at 08:15 +0900, OGAWA Hirofumi wrote:
> Andy Shevchenko <andy.shevchenko@xxxxxxxxx> writes:
>
> > Actually here we will change endianess.
> > So, my question is what endianess is right here? If the original code
> > okay, then patch should be rewritten like this:
> >
> > rc = hex2bin(op++, ip + 3, 1);
> > if (rc < 0)
> > return -EINVAL;
> >
> > rc = hex2bin(op++, ip + 1, 1);
> > if (rc < 0)
> > return -EINVAL;
>
> Original code may work only for little endian. Well, anyway, the output
> should be wchar_t (u16) of native endian.

> So, I think it should be something like
>
> u8 uc[2];
> if (hex2bin(uc, ip + 1, 2) < 0)
> return -EINVAL;
> *(wchar_t *)op = uc[0] << 8 | uc[1];
> This should be readable more.
It might be so, but it's not okay to do such constructions in C

fs/fat/namei_vfat.c:535:1: warning: ISO C90 forbids mixed declarations
and code [-Wdeclaration-after-statement]

So, I will resend patch as I proposed with additional comments.


--
Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Intel Finland Oy
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