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

From: Greg KH
Date: Thu Jul 28 2005 - 11:23:55 EST

On Thu, Jul 28, 2005 at 12:57:51PM +0100, Ian Pratt wrote:
> > > 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
> xen/x86.

I agree, but not for i386, which is what the patch was trying to change.

If this is a fix for xen, fine, then say so in the changelog information
for the patch, as it is, no such information was given.


greg k-h
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