[PATCH] gfp_t: infrastructure

Beginning of gfp_t annotations:

 - -Wbitwise added to CHECKFLAGS
 - old __bitwise renamed to __bitwise__
 - __bitwise defined to either __bitwise__ or nothing, depending on
   __CHECK_ENDIAN__ being defined
 - gfp_t switched from __nocast to __bitwise__
 - force cast to gfp_t added to __GFP_... constants
 - new helper - gfp_zone(); extracts zone bits out of gfp_t value and casts
   the result to int

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e1d3d77..aa43ae3 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1089,7 +1089,7 @@
  */
 unsigned int nr_free_buffer_pages(void)
 {
-	return nr_free_zone_pages(GFP_USER & GFP_ZONEMASK);
+	return nr_free_zone_pages(gfp_zone(GFP_USER));
 }
 
 /*
@@ -1097,7 +1097,7 @@
  */
 unsigned int nr_free_pagecache_pages(void)
 {
-	return nr_free_zone_pages(GFP_HIGHUSER & GFP_ZONEMASK);
+	return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER));
 }
 
 #ifdef CONFIG_HIGHMEM