[AGPGART] remove private page protection map

AGP keeps its own copy of the protection_map, upcoming DRM changes will
also require access to this map from modules.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Dave Airlie <airlied@linux.ie>
Signed-off-by: Dave Jones <davej@redhat.com>

drivers/char/agp/frontend.c

@@ -151,35 +151,12 @@ static void agp_add_seg_to_client(struct agp_client *client,
 	client->segments = seg;
 }
 
-/* Originally taken from linux/mm/mmap.c from the array
- * protection_map.
- * The original really should be exported to modules, or
- * some routine which does the conversion for you
- */
-
-static const pgprot_t my_protect_map[16] =
-{
-	__P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
-	__S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
-};
-
 static pgprot_t agp_convert_mmap_flags(int prot)
 {
-#define _trans(x,bit1,bit2) \
-((bit1==bit2)?(x&bit1):(x&bit1)?bit2:0)
-
 	unsigned long prot_bits;
-	pgprot_t temp;
-
-	prot_bits = _trans(prot, PROT_READ, VM_READ) |
-	    _trans(prot, PROT_WRITE, VM_WRITE) |
-	    _trans(prot, PROT_EXEC, VM_EXEC);
-
-	prot_bits |= VM_SHARED;
 
-	temp = my_protect_map[prot_bits & 0x0000000f];
-
-	return temp;
+	prot_bits = calc_vm_prot_bits(prot) | VM_SHARED;
+	return vm_get_page_prot(prot_bits);
 }
 
 static int agp_create_segment(struct agp_client *client, struct agp_region *region)

include/linux/mm.h

@@ -1012,6 +1012,7 @@ static inline unsigned long vma_pages(struct vm_area_struct *vma)
 	return (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
 }
 
+pgprot_t vm_get_page_prot(unsigned long vm_flags);
 struct vm_area_struct *find_extend_vma(struct mm_struct *, unsigned long addr);
 struct page *vmalloc_to_page(void *addr);
 unsigned long vmalloc_to_pfn(void *addr);

mm/mmap.c

@@ -60,6 +60,13 @@ pgprot_t protection_map[16] = {
 	__S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
 };
 
+pgprot_t vm_get_page_prot(unsigned long vm_flags)
+{
+	return protection_map[vm_flags &
+				(VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)];
+}
+EXPORT_SYMBOL(vm_get_page_prot);
+
 int sysctl_overcommit_memory = OVERCOMMIT_GUESS;  /* heuristic overcommit */
 int sysctl_overcommit_ratio = 50;	/* default is 50% */
 int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;