vmscan.c: fix invalid strict_strtoul() check in write_scan_unevictabl…

…e_node() write_scan_unevictable_node() checks the value req returned by strict_strtoul() and returns 1 if req is 0. However, when strict_strtoul() returns 0, it means successful conversion of buf to unsigned long. Due to this, the function was not proceeding to scan the zones for unevictable pages even though we write a valid value to the scan_unevictable_pages sys file. Change this check slightly to check for invalid value in buf as well as 0 value stored in res after successful conversion via strict_strtoul. In both cases, we do not perform the scanning of this node's zones. Signed-off-by: Kautuk Consul <[email protected]> Reviewed-by: KAMEZAWA Hiroyuki <[email protected]> Cc: Johannes Weiner <[email protected]> Cc: Lee Schermerhorn <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
cbmeeks · Nov 1, 2011 · 3f38099 · 3f38099
1 parent 4e9dc5d
commit 3f38099
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/mm/vmscan.c b/mm/vmscan.c
@@ -3520,8 +3520,8 @@ static ssize_t write_scan_unevictable_node(struct sys_device *dev,
 	unsigned long res;
 	unsigned long req = strict_strtoul(buf, 10, &res);
 
-	if (!req)
-		return 1;	/* zero is no-op */
+	if (req || !res)
+		return 1; /* Invalid input or zero is no-op */
 
 	for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
 		if (!populated_zone(zone))