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>

arch/x86/mm/fault.c

@@ -907,10 +907,8 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
 	force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk);
 }
 
-#ifdef CONFIG_X86_64
 DEFINE_SPINLOCK(pgd_lock);
 LIST_HEAD(pgd_list);
-#endif
 
 void vmalloc_sync_all(void)
 {
@@ -935,13 +933,11 @@ void vmalloc_sync_all(void)
 			struct page *page;
 
 			spin_lock_irqsave(&pgd_lock, flags);
-			for (page = pgd_list; page; page =
-					(struct page *)page->index)
+			list_for_each_entry(page, &pgd_list, lru) {
 				if (!vmalloc_sync_one(page_address(page),
-								address)) {
-					BUG_ON(page != pgd_list);
+						      address))
 					break;
-				}
+			}
 			spin_unlock_irqrestore(&pgd_lock, flags);
 			if (!page)
 				set_bit(pgd_index(address), insync);

arch/x86/mm/pageattr.c

@@ -175,7 +175,7 @@ static void __set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte)
 	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;

arch/x86/mm/pgtable_32.c

@@ -205,27 +205,18 @@ struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
  * vmalloc faults work because attached pagetables are never freed.
  * -- wli
  */
-DEFINE_SPINLOCK(pgd_lock);
-struct page *pgd_list;
-
 static inline void pgd_list_add(pgd_t *pgd)
 {
 	struct page *page = virt_to_page(pgd);
-	page->index = (unsigned long)pgd_list;
-	if (pgd_list)
-		set_page_private(pgd_list, (unsigned long)&page->index);
-	pgd_list = page;
-	set_page_private(page, (unsigned long)&pgd_list);
+
+	list_add(&page->lru, &pgd_list);
 }
 
 static inline void pgd_list_del(pgd_t *pgd)
 {
-	struct page *next, **pprev, *page = virt_to_page(pgd);
-	next = (struct page *)page->index;
-	pprev = (struct page **)page_private(page);
-	*pprev = next;
-	if (next)
-		set_page_private(next, (unsigned long)pprev);
+	struct page *page = virt_to_page(pgd);
+
+	list_del(&page->lru);
 }
 
 

include/asm-x86/pgtable.h

@@ -131,6 +131,8 @@ extern pteval_t __PAGE_KERNEL, __PAGE_KERNEL_EXEC;
 extern unsigned long empty_zero_page[PAGE_SIZE/sizeof(unsigned long)];
 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
 
+extern spinlock_t pgd_lock;
+extern struct list_head pgd_list;
 
 /*
  * The following only work if pte_present() is true.

include/asm-x86/pgtable_32.h

@@ -27,8 +27,6 @@ struct vm_area_struct;
 
 extern pgd_t swapper_pg_dir[1024];
 extern struct kmem_cache *pmd_cache;
-extern spinlock_t pgd_lock;
-extern struct page *pgd_list;
 void check_pgt_cache(void);
 
 static inline void pgtable_cache_init(void) {}

include/asm-x86/pgtable_64.h

@@ -240,9 +240,6 @@ static inline unsigned long pmd_bad(pmd_t pmd)
 #define __pte_to_swp_entry(pte)		((swp_entry_t) { pte_val(pte) })
 #define __swp_entry_to_pte(x)		((pte_t) { .pte = (x).val })
 
-extern spinlock_t pgd_lock;
-extern struct list_head pgd_list;
-
 extern int kern_addr_valid(unsigned long addr); 
 
 #define io_remap_pfn_range(vma, vaddr, pfn, size, prot)		\