mm: add & use zone_end_pfn() and zone_spans_pfn()

Add 2 helpers (zone_end_pfn() and zone_spans_pfn()) to reduce code
duplication.

This also switches to using them in compaction (where an additional
variable needed to be renamed), page_alloc, vmstat, memory_hotplug, and
kmemleak.

Note that in compaction.c I avoid calling zone_end_pfn() repeatedly
because I expect at some point the sycronization issues with start_pfn &
spanned_pages will need fixing, either by actually using the seqlock or
clever memory barrier usage.

Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: David Hansen <dave@linux.vnet.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 5 deletions

diff --git a/mm/compaction.c b/mm/compaction.c
index 25e75e3e2ac6..05ccb4cc0bdb 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -86,7 +86,7 @@ static inline bool isolation_suitable(struct compact_control *cc,
 static void __reset_isolation_suitable(struct zone *zone)
 {
         unsigned long start_pfn = zone->zone_start_pfn;
-        unsigned long end_pfn = zone->zone_start_pfn + zone->spanned_pages;
+        unsigned long end_pfn = zone_end_pfn(zone);
         unsigned long pfn;
 
         zone->compact_cached_migrate_pfn = start_pfn;
@@ -647,7 +647,7 @@ static void isolate_freepages(struct zone *zone,
                                 struct compact_control *cc)
 {
         struct page *page;
-        unsigned long high_pfn, low_pfn, pfn, zone_end_pfn, end_pfn;
+        unsigned long high_pfn, low_pfn, pfn, z_end_pfn, end_pfn;
         int nr_freepages = cc->nr_freepages;
         struct list_head *freelist = &cc->freepages;
 
@@ -666,7 +666,7 @@ static void isolate_freepages(struct zone *zone,
          */
         high_pfn = min(low_pfn, pfn);
 
-        zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
+        z_end_pfn = zone_end_pfn(zone);
 
         /*
          * Isolate free pages until enough are available to migrate the
@@ -709,7 +709,7 @@ static void isolate_freepages(struct zone *zone,
                  * only scans within a pageblock
                  */
                 end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
-                end_pfn = min(end_pfn, zone_end_pfn);
+                end_pfn = min(end_pfn, z_end_pfn);
                 isolated = isolate_freepages_block(cc, pfn, end_pfn,
                                                    freelist, false);
                 nr_freepages += isolated;
@@ -923,7 +923,7 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
 {
         int ret;
         unsigned long start_pfn = zone->zone_start_pfn;
-        unsigned long end_pfn = zone->zone_start_pfn + zone->spanned_pages;
+        unsigned long end_pfn = zone_end_pfn(zone);
 
         ret = compaction_suitable(zone, cc->order);
         switch (ret) {