mm: re-architect the VM_UNPAGED logic

This replaces the (in my opinion horrible) VM_UNMAPPED logic with very
explicit support for a "remapped page range" aka VM_PFNMAP.  It allows a
VM area to contain an arbitrary range of page table entries that the VM
never touches, and never considers to be normal pages.

Any user of "remap_pfn_range()" automatically gets this new
functionality, and doesn't even have to mark the pages reserved or
indeed mark them any other way.  It just works.  As a side effect, doing
mmap() on /dev/mem works for arbitrary ranges.

Sparc update from David in the next commit.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/mm/nommu.c b/mm/nommu.c
index 6deb6ab..c119681 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1045,7 +1045,7 @@ struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
 
 EXPORT_SYMBOL(find_vma);
 
-struct page *follow_page(struct mm_struct *mm, unsigned long address,
+struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
 			unsigned int foll_flags)
 {
 	return NULL;