From fef578056f3dbf0facff098b32868fb3b5e5a97c Mon Sep 17 00:00:00 2001
From: Miaohe Lin <linmiaohe@huawei.com>
Date: Thu, 2 Sep 2021 15:01:05 -0700
Subject: [PATCH] mm/vmstat: simplify the array size calculation

References: bsc#1190208 (MM functional and performance backports)
Patch-mainline: v5.15-rc1
Git-commit: 64632fd3eb4611780a1190362f2119d8f2bb5465

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>
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
 mm/vmstat.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/mm/vmstat.c b/mm/vmstat.c
index d72aad85bd89..3f0fe7f630f5 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1889,17 +1889,15 @@ 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;
 }