[PATCH] mm: vmscan: simplify lruvec_lru_size() fix

[Johannes Weiner]

get_scan_count() passes MAX_NR_ZONES for the reclaim index, which is
beyond the range of valid zone indexes, but used to be handled before
the patch. Every other callsite in vmscan.c passes MAX_NR_ZONES - 1 to
express "all zones, please", so do the same here.

Reported-by: Qian Cai <cai@xxxxxx>
Reported-by: Chris Down <chris@xxxxxxxxxxxxxx>
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
---
 mm/vmscan.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index df859b1d583c..34ad8a0f3f27 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2322,10 +2322,10 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc,
 	 * anon in [0], file in [1]
 	 */
 
-	anon  = lruvec_lru_size(lruvec, LRU_ACTIVE_ANON, MAX_NR_ZONES) +
-		lruvec_lru_size(lruvec, LRU_INACTIVE_ANON, MAX_NR_ZONES);
-	file  = lruvec_lru_size(lruvec, LRU_ACTIVE_FILE, MAX_NR_ZONES) +
-		lruvec_lru_size(lruvec, LRU_INACTIVE_FILE, MAX_NR_ZONES);
+	anon  = lruvec_lru_size(lruvec, LRU_ACTIVE_ANON, MAX_NR_ZONES - 1) +
+		lruvec_lru_size(lruvec, LRU_INACTIVE_ANON, MAX_NR_ZONES - 1);
+	file  = lruvec_lru_size(lruvec, LRU_ACTIVE_FILE, MAX_NR_ZONES - 1) +
+		lruvec_lru_size(lruvec, LRU_INACTIVE_FILE, MAX_NR_ZONES - 1);
 
 	spin_lock_irq(&pgdat->lru_lock);
 	if (unlikely(reclaim_stat->recent_scanned[0] > anon / 4)) {
-- 
2.24.0