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, 4 insertions, 8 deletions

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 5609a31bdf22..bec88c81244e 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -189,17 +189,15 @@ static int check_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
 
         orig_pte = pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
         do {
-                unsigned long pfn;
+                struct page *page;
                 unsigned int nid;
 
                 if (!pte_present(*pte))
                         continue;
-                pfn = pte_pfn(*pte);
-                if (!pfn_valid(pfn)) {
-                        print_bad_pte(vma, *pte, addr);
+                page = vm_normal_page(vma, addr, *pte);
+                if (!page)
                         continue;
-                }
-                nid = pfn_to_nid(pfn);
+                nid = page_to_nid(page);
                 if (!node_isset(nid, *nodes))
                         break;
         } while (pte++, addr += PAGE_SIZE, addr != end);
@@ -269,8 +267,6 @@ check_range(struct mm_struct *mm, unsigned long start, unsigned long end,
         first = find_vma(mm, start);
         if (!first)
                 return ERR_PTR(-EFAULT);
-        if (first->vm_flags & VM_UNPAGED)
-                return ERR_PTR(-EACCES);
         prev = NULL;
         for (vma = first; vma && vma->vm_start < end; vma = vma->vm_next) {
                 if (!vma->vm_next && vma->vm_end < end)