Re: Add sparse "__iomem" infrastructure to check PCI address usage

[Jeff Garzik <jgarzik@pobox.com>]

Linus Torvalds wrote:
> On Sun, 12 Sep 2004, Jeff Garzik wrote:
>>1) what does force do? it doesn't appear to be in gcc 3.3.3 docs.

> It doesn't do anything for gcc. You're looking at the sparse-only code.

doh, and thanks for the info.


>>2) is "volatile ... __force" redundant?

> No, although it's likely to be a strange combination. If you want to force 
> a static address space conversion to a volatile pointer, you can do so. I 
> don't see _why_ you'd want to do it ;)

Well the reason I ask....

static inline void writeb(unsigned char b, volatile void __iomem *addr)
{
         *(volatile unsigned char __force *) addr = b;
}
static inline void writew(unsigned short b, volatile void __iomem *addr)
{
         *(volatile unsigned short __force *) addr = b;
}
static inline void writel(unsigned int b, volatile void __iomem *addr)
{
         *(volatile unsigned int __force *) addr = b;
}


>>3) can we use 'malloc' attribute on kmalloc?

> Since we can't use the gcc alias analysis anyway (it's too broken until
> very late gcc versions), the gcc 'malloc' attribute shouldn't make any
> difference that I can tell.
> 
> But there wouldn't be anything _wrong_ in adding it to kmalloc(), if 
> that's what you're asking.

That's what I'm asking.

Thanks,

	Jeff