mm/vmalloc.c: move 'area->pages' after if statement

If !area->pages statement is true where memory allocation fails, area is
freed.

In this case 'area->pages = pages' should not executed.  So move
'area->pages = pages' after if statement.

[akpm@linux-foundation.org: give area->pages the same treatment]
Link: http://lkml.kernel.org/r/20190830035716.GA190684@LGEARND20B15
Signed-off-by: Austin Kim <austindh.kim@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Roman Penyaev <rpenyaev@suse.de>
Cc: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/vmalloc.c

@@ -2409,7 +2409,6 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
 	nr_pages = get_vm_area_size(area) >> PAGE_SHIFT;
 	array_size = (nr_pages * sizeof(struct page *));
 
-	area->nr_pages = nr_pages;
 	/* Please note that the recursion is strictly bounded. */
 	if (array_size > PAGE_SIZE) {
 		pages = __vmalloc_node(array_size, 1, nested_gfp|highmem_mask,
@@ -2417,13 +2416,16 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
 	} else {
 		pages = kmalloc_node(array_size, nested_gfp, node);
 	}
-	area->pages = pages;
-	if (!area->pages) {
+
+	if (!pages) {
 		remove_vm_area(area->addr);
 		kfree(area);
 		return NULL;
 	}
 
+	area->pages = pages;
+	area->nr_pages = nr_pages;
+
 	for (i = 0; i < area->nr_pages; i++) {
 		struct page *page;