On Wed, Oct 11, 2006 at 12:12:19PM +0200, Thomas Hellstrom wrote::).
Nick, I just realized: would it be possible to have a pgprot_t argument to this one, instead of it using vma->vm_pgprot?
The motivation for this (DRM again) is that some architectures (powerpc) cannot map the AGP aperture through IO space, but needs to remap the page from memory with a nocache attribute set. Others need special pgprot settings for write-combined mappings.
Now, there's a possibility to change vma->vm_pgprot during the first ->fault(), but again, we only have the mmap_sem in read mode.
I don't see a problem with that. It would be nice if vm_pgprot could
be kept in synch with the pte protections, but I guess a crazy
driver should be allowed to do anything it wants ;)