Re: [PATCH] fix sparse warning from include/linux/mmzone.h

[Harvey Harrison <harvey.harrison@gmail.com>]

include/linux/mmzone.h:640:22: warning: potentially expensive pointer subtraction

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
---
Linus, something like the following?

 include/linux/mmzone.h |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 8d8d197..7ed2922 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -637,9 +637,10 @@ static inline int is_normal_idx(enum zone_type idx)
 static inline int is_highmem(struct zone *zone)
 {
 #ifdef CONFIG_HIGHMEM
-	int zone_idx = zone - zone->zone_pgdat->node_zones;
-	return zone_idx == ZONE_HIGHMEM ||
-		(zone_idx == ZONE_MOVABLE && zone_movable_is_highmem());
+	struct zone *base = zone->zone_pgdat->node_zones;
+
+	return zone == base + ZONE_HIGHMEM ||
+		(zone == base + ZONE_MOVABLE && zone_movable_is_highmem());
 #else
 	return 0;
 #endif
-- 
1.5.4.1219.g65b9