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, 3 insertions, 4 deletions

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 9ab97cef0daa..50bd5a8f0446 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -402,12 +402,11 @@ struct numa_maps {
 /*
  * Calculate numa node maps for a vma
  */
-static struct numa_maps *get_numa_maps(const struct vm_area_struct *vma)
+static struct numa_maps *get_numa_maps(struct vm_area_struct *vma)
 {
+        int i;
         struct page *page;
         unsigned long vaddr;
-        struct mm_struct *mm = vma->vm_mm;
-        int i;
         struct numa_maps *md = kmalloc(sizeof(struct numa_maps), GFP_KERNEL);
 
         if (!md)
@@ -420,7 +419,7 @@ static struct numa_maps *get_numa_maps(const struct vm_area_struct *vma)
                 md->node[i] =0;
 
         for (vaddr = vma->vm_start; vaddr < vma->vm_end; vaddr += PAGE_SIZE) {
-                page = follow_page(mm, vaddr, 0);
+                page = follow_page(vma, vaddr, 0);
                 if (page) {
                         int count = page_mapcount(page);