Re: unsigned long ioremap()?

[Abramo Bagnara]

"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:[e-mail]

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It sounds good!