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/memory_hotplug.c b/mm/memory_hotplug.c
index dda1ca695a08..8b3235eedf3d 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -299,7 +299,7 @@ static int __meminit move_pfn_range_left(struct zone *z1, struct zone *z2,
         pgdat_resize_lock(z1->zone_pgdat, &flags);
 
         /* can't move pfns which are higher than @z2 */
-        if (end_pfn > z2->zone_start_pfn + z2->spanned_pages)
+        if (end_pfn > zone_end_pfn(z2))
                 goto out_fail;
         /* the move out part mast at the left most of @z2 */
         if (start_pfn > z2->zone_start_pfn)
@@ -315,7 +315,7 @@ static int __meminit move_pfn_range_left(struct zone *z1, struct zone *z2,
                 z1_start_pfn = start_pfn;
 
         resize_zone(z1, z1_start_pfn, end_pfn);
-        resize_zone(z2, end_pfn, z2->zone_start_pfn + z2->spanned_pages);
+        resize_zone(z2, end_pfn, zone_end_pfn(z2));
 
         pgdat_resize_unlock(z1->zone_pgdat, &flags);
 
@@ -347,15 +347,15 @@ static int __meminit move_pfn_range_right(struct zone *z1, struct zone *z2,
         if (z1->zone_start_pfn > start_pfn)
                 goto out_fail;
         /* the move out part mast at the right most of @z1 */
-        if (z1->zone_start_pfn + z1->spanned_pages >  end_pfn)
+        if (zone_end_pfn(z1) >  end_pfn)
                 goto out_fail;
         /* must included/overlap */
-        if (start_pfn >= z1->zone_start_pfn + z1->spanned_pages)
+        if (start_pfn >= zone_end_pfn(z1))
                 goto out_fail;
 
         /* use end_pfn for z2's end_pfn if z2 is empty */
         if (z2->spanned_pages)
-                z2_end_pfn = z2->zone_start_pfn + z2->spanned_pages;
+                z2_end_pfn = zone_end_pfn(z2);
         else
                 z2_end_pfn = end_pfn;