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vmscan.c: fix invalid strict_strtoul() check in write_scan_unevictable_node()

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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 <consul.kautuk@gmail.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Kautuk Consul 2011-10-31 17:09:11 -07:00 committed by Linus Torvalds
parent 4e9dc5df46
commit 3f380998ae
1 changed files with 2 additions and 2 deletions
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4
mm/vmscan.c
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@ -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))