From: Chanho Min <chanho.min@lge.com>
To: Andrew Morton <akpm@linux-foundation.org>,
        Mel Gorman <mgorman@techsingularity.net>,
        Vlastimil Babka <vbabka@suse.cz>, David Rientjes <rientjes@google.com>,
        Michal Hocko <mhocko@suse.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Zhang Zhen <zhenzhang.zhang@huawei.com>
CC: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Gunho Lee <gunho.lee@lge.com>, Chanho Min <chanho.min@lge.com>
Subject: [PATCH] mm/highmem: simplify is_highmem()
Date: Wed, 30 Mar 2016 13:43:42 +0900
Message-ID: <1459313022-11750-1-git-send-email-chanho.min@lge.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 914
Lines: 27

The is_highmem() is can be simplified by use of is_highmem_idx().
This patch removes redundant code and will make it easier to maintain
if the zone policy is changed or a new zone is added.

Signed-off-by: Chanho Min <chanho.min@lge.com>
---
 include/linux/mmzone.h |    5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index e23a9e7..9ac90c3 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -817,10 +817,7 @@ static inline int is_highmem_idx(enum zone_type idx)
 static inline int is_highmem(struct zone *zone)
 {
 #ifdef CONFIG_HIGHMEM
-	int zone_off = (char *)zone - (char *)zone->zone_pgdat->node_zones;
-	return zone_off == ZONE_HIGHMEM * sizeof(*zone) ||
-	       (zone_off == ZONE_MOVABLE * sizeof(*zone) &&
-		zone_movable_is_highmem());
+	return is_highmem_idx(zone_idx(zone));
 #else
 	return 0;
 #endif
-- 
1.7.9.5