Re: unsigned long ioremap()?

Abramo Bagnara
2001-05-03T07:54:19Z

"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

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It sounds good!