x86: use the same pgd_list for PAE and 64-bit

Use a standard list threaded through page->lru for maintaining the pgd
list on PAE.  This is the same as 64-bit, and seems saner than using a
non-standard list via page->index.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index ec07c18..1cc6607 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -175,7 +175,7 @@
 	if (!SHARED_KERNEL_PMD) {
 		struct page *page;
 
-		for (page = pgd_list; page; page = (struct page *)page->index) {
+		list_for_each_entry(page, &pgd_list, lru) {
 			pgd_t *pgd;
 			pud_t *pud;
 			pmd_t *pmd;