mm/mempolicy: use PAGE_ALIGN instead of open-coding it

Replace the simple calculation with PAGE_ALIGN.

Link: https://lkml.kernel.org/r/20220913015505.1998958-1-zuoze1@huawei.comSigned-off-by: ze zuo <zuoze1@huawei.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/mempolicy.c

@@ -1270,7 +1270,7 @@ static long do_mbind(unsigned long start, unsigned long len,
 	if (mode == MPOL_DEFAULT)
 		flags &= ~MPOL_MF_STRICT;
 
-	len = (len + PAGE_SIZE - 1) & PAGE_MASK;
+	len = PAGE_ALIGN(len);
 	end = start + len;
 
 	if (end < start)
@@ -1507,7 +1507,7 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le
 	if (home_node >= MAX_NUMNODES || !node_online(home_node))
 		return -EINVAL;
 
-	len = (len + PAGE_SIZE - 1) & PAGE_MASK;
+	len = PAGE_ALIGN(len);
 	end = start + len;
 
 	if (end < start)