mm/mempolicy.c: remove unnecessary is_valid_nodemask()

When nodes is true, nsc->mask2 has already been filtered by nsc->mask1,
which has already factored in node_states[N_MEMORY].
Signed-off-by: NZhihui Zhang <zzhsuny@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/mempolicy.c

@@ -162,12 +162,6 @@ static const struct mempolicy_operations {
 			enum mpol_rebind_step step);
 } mpol_ops[MPOL_MAX];
 
-/* Check that the nodemask contains at least one populated zone */
-static int is_valid_nodemask(const nodemask_t *nodemask)
-{
-	return nodes_intersects(*nodemask, node_states[N_MEMORY]);
-}
-
 static inline int mpol_store_user_nodemask(const struct mempolicy *pol)
 {
 	return pol->flags & MPOL_MODE_FLAGS;
@@ -202,7 +196,7 @@ static int mpol_new_preferred(struct mempolicy *pol, const nodemask_t *nodes)
 
 static int mpol_new_bind(struct mempolicy *pol, const nodemask_t *nodes)
 {
-	if (!is_valid_nodemask(nodes))
+	if (nodes_empty(*nodes))
 		return -EINVAL;
 	pol->v.nodes = *nodes;
 	return 0;
@@ -234,7 +228,7 @@ static int mpol_set_nodemask(struct mempolicy *pol,
 		nodes = NULL;	/* explicit local allocation */
 	else {
 		if (pol->flags & MPOL_F_RELATIVE_NODES)
-			mpol_relative_nodemask(&nsc->mask2, nodes,&nsc->mask1);
+			mpol_relative_nodemask(&nsc->mask2, nodes, &nsc->mask1);
 		else
 			nodes_and(nsc->mask2, *nodes, nsc->mask1);