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/drivers/char/mem.c b/drivers/char/mem.c
index 29c3b631445a..91dd669273e0 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -591,7 +591,7 @@ static inline size_t read_zero_pagealigned(char __user * buf, size_t size)
 
                 if (vma->vm_start > addr || (vma->vm_flags & VM_WRITE) == 0)
                         goto out_up;
-                if (vma->vm_flags & (VM_SHARED | VM_HUGETLB | VM_UNPAGED))
+                if (vma->vm_flags & (VM_SHARED | VM_HUGETLB))
                         break;
                 count = vma->vm_end - addr;
                 if (count > size)