Re: unsigned long ioremap()?

From: Abramo Bagnara (abramo@alsa-project.org)
Date: Thu May 03 2001 - 02:53:36 EST

"David S. Miller" wrote:
>
> Geert Uytterhoeven writes:
> > Since you're not allowed to use direct memory dereferencing on ioremapped
> > areas, wouldn't it be more logical to let ioremap() return an unsigned long
> > instead of a void *?
> >
> > Of course we then have to change readb() and friends to take a long as well,
> > but at least we'd get compiler warnings when someone tries to do a direct
> > dereference.
>
> There is a school of thought which believes that:
>
> struct xdev_regs {
> u32 reg1;
> u32 reg2;
> };
>
> val = readl(&regs->reg2);
>
> is cleaner than:
>
> #define REG1 0x00
> #define REG2 0x04
>
> val = readl(regs + REG2);
>
> I'm personally ambivalent and believe that both cases should be allowed.

The problem I see is that with the former solution nothing prevents from
to do:

        regs->reg2 = 13;

That's indeed the reason to change ioremap prototype for 2.5. 

-- 
Abramo Bagnara                       mailto:abramo@alsa-project.org

Opera Unica                          Phone: +39.546.656023
Via Emilia Interna, 140
48014 Castel Bolognese (RA) - Italy

ALSA project               http://www.alsa-project.org
It sounds good!
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This archive was generated by hypermail 2b29 : Mon May 07 2001 - 21:00:15 EST