mm, vmalloc: constify allocation mask

tmp_mask in the __vmalloc_area_node() iteration never changes so it can
be moved into function scope and marked with const.  This causes the
movl and orl to only be done once per call rather than area->nr_pages
times.

nested_gfp can also be marked const.
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/vmalloc.c

@@ -1566,7 +1566,8 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
 	const int order = 0;
 	struct page **pages;
 	unsigned int nr_pages, array_size, i;
-	gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO;
+	const gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO;
+	const gfp_t alloc_mask = gfp_mask | __GFP_NOWARN;
 
 	nr_pages = get_vm_area_size(area) >> PAGE_SHIFT;
 	array_size = (nr_pages * sizeof(struct page *));
@@ -1589,12 +1590,11 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
 
 	for (i = 0; i < area->nr_pages; i++) {
 		struct page *page;
-		gfp_t tmp_mask = gfp_mask | __GFP_NOWARN;
 
 		if (node == NUMA_NO_NODE)
-			page = alloc_page(tmp_mask);
+			page = alloc_page(alloc_mask);
 		else
-			page = alloc_pages_node(node, tmp_mask, order);
+			page = alloc_pages_node(node, alloc_mask, order);
 
 		if (unlikely(!page)) {
 			/* Successfully allocated i pages, free them in __vunmap() */