RE: [openib-general] Re: [PATCH] arch/xx/pci: remap_pfn_range -> io_remap_pfn_range

From: Ian Pratt
Date: Thu Jul 28 2005 - 06:59:14 EST

> > Greg> Hm, you do realize that io_remap_pfn_range() is the same
> > Greg> thing as remap_pfn_range() on i386, right?
> >
> > Greg> So, why would this patch change anything?
> >
> > It's not the same thing under Xen. I think this patch
> fixes userspace
> > access to PCI memory for XenLinux.
> But Xen is a separate arch, and hence, will get different pci
> arch specific functions, right?
> In short, what is this patch trying to fix? What is the
> problem anyone is seeing with the existing code?

As I understand it, remap_pfn_range should be used for mapping pages
that are backed by memory, and io_remap_pfn_range should be used for
mapping MMIO regions.
There's a distinciton between the two for architectures like Sparc and

For example, drivers/char/mem.c uses io_remap_pfn_range for mmap'ing

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at