[PATCH 3/3] memory_hotplug: Optimise try_offline_memory_block()

["Matthew Wilcox (Oracle)" <willy@infradead.org>]

Extract the zone number directly from the page instead of using the page's
zone number to look up the zone and asking the zone what its number is.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/memory_hotplug.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 0be83039c3b5..80713bdf13dc 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -2327,7 +2327,7 @@ static int try_offline_memory_block(struct memory_block *mem, void *arg)
 	 * by offlining code ... so we don't care about that.
 	 */
 	page = pfn_to_online_page(section_nr_to_pfn(mem->start_section_nr));
-	if (page && zone_idx(page_zone(page)) == ZONE_MOVABLE)
+	if (page && page_zonenum(page) == ZONE_MOVABLE)
 		online_type = MMOP_ONLINE_MOVABLE;
 
 	rc = device_offline(&mem->dev);
-- 
2.47.2