arch/um/kernel/mem.c: remove arch_validate()

- Remove arch_validate(), because no one uses it.

- Remove useless macro HAVE_ARCH_VALIDATE.

- Make the variable 'empty_bad_page' static.

Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: WANG Cong <wangcong@zeuux.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/um/kernel/mem.c

@@ -21,7 +21,7 @@
 /* allocated in paging_init, zeroed in mem_init, and unchanged thereafter */
 unsigned long *empty_zero_page = NULL;
 /* allocated in paging_init and unchanged thereafter */
-unsigned long *empty_bad_page = NULL;
+static unsigned long *empty_bad_page = NULL;
 
 /*
  * Initialized during boot, and readonly for initializing page tables
@@ -240,37 +240,6 @@ void __init paging_init(void)
 #endif
 }
 
-struct page *arch_validate(struct page *page, gfp_t mask, int order)
-{
-	unsigned long addr, zero = 0;
-	int i;
-
- again:
-	if (page == NULL)
-		return page;
-	if (PageHighMem(page))
-		return page;
-
-	addr = (unsigned long) page_address(page);
-	for (i = 0; i < (1 << order); i++) {
-		current->thread.fault_addr = (void *) addr;
-		if (__do_copy_to_user((void __user *) addr, &zero,
-				     sizeof(zero),
-				     &current->thread.fault_addr,
-				     &current->thread.fault_catcher)) {
-			if (!(mask & __GFP_WAIT))
-				return NULL;
-			else break;
-		}
-		addr += PAGE_SIZE;
-	}
-
-	if (i == (1 << order))
-		return page;
-	page = alloc_pages(mask, order);
-	goto again;
-}
-
 /*
  * This can't do anything because nothing in the kernel image can be freed
  * since it's not in kernel physical memory.