mm/vmstat: simplify the array size calculation

We can replace the array_num * sizeof(array[0]) with sizeof(array) to
simplify the code.

Link: https://lkml.kernel.org/r/20210715122911.15700-3-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/vmstat.c b/mm/vmstat.c
index 5bd621e..c4634dc 100644 (file)
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1891,17 +1891,15 @@ static bool need_update(int cpu)
                /*
                 * The fast way of checking if there are any vmstat diffs.
                 */
-               if (memchr_inv(pzstats->vm_stat_diff, 0, NR_VM_ZONE_STAT_ITEMS *
-                              sizeof(pzstats->vm_stat_diff[0])))
+               if (memchr_inv(pzstats->vm_stat_diff, 0, sizeof(pzstats->vm_stat_diff)))
                        return true;
 
                if (last_pgdat == zone->zone_pgdat)
                        continue;
                last_pgdat = zone->zone_pgdat;
                n = per_cpu_ptr(zone->zone_pgdat->per_cpu_nodestats, cpu);
-               if (memchr_inv(n->vm_node_stat_diff, 0, NR_VM_NODE_STAT_ITEMS *
-                              sizeof(n->vm_node_stat_diff[0])))
-                   return true;
+               if (memchr_inv(n->vm_node_stat_diff, 0, sizeof(n->vm_node_stat_diff)))
+                       return true;
        }
        return false;
 }