mm: page_isolation: MIGRATE_CMA isolation functions added

This commit changes various functions that change pages and
pageblocks migrate type between MIGRATE_ISOLATE and
MIGRATE_MOVABLE in such a way as to allow to work with
MIGRATE_CMA migrate type.

Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: Rob Clark <rob.clark@linaro.org>
Tested-by: Ohad Ben-Cohen <ohad@wizery.com>
Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Tested-by: Robert Nelson <robertcnelson@gmail.com>
Tested-by: Barry Song <Baohua.Song@csr.com>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 0869eb1..116c087 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5582,7 +5582,7 @@
 	return ret;
 }
 
-void unset_migratetype_isolate(struct page *page)
+void unset_migratetype_isolate(struct page *page, unsigned migratetype)
 {
 	struct zone *zone;
 	unsigned long flags;
@@ -5590,8 +5590,8 @@
 	spin_lock_irqsave(&zone->lock, flags);
 	if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
 		goto out;
-	set_pageblock_migratetype(page, MIGRATE_MOVABLE);
-	move_freepages_block(zone, page, MIGRATE_MOVABLE);
+	set_pageblock_migratetype(page, migratetype);
+	move_freepages_block(zone, page, migratetype);
 out:
 	spin_unlock_irqrestore(&zone->lock, flags);
 }
@@ -5669,6 +5669,10 @@
  * alloc_contig_range() -- tries to allocate given range of pages
  * @start:	start PFN to allocate
  * @end:	one-past-the-last PFN to allocate
+ * @migratetype:	migratetype of the underlaying pageblocks (either
+ *			#MIGRATE_MOVABLE or #MIGRATE_CMA).  All pageblocks
+ *			in range must have the same migratetype and it must
+ *			be either of the two.
  *
  * The PFN range does not have to be pageblock or MAX_ORDER_NR_PAGES
  * aligned, however it's the caller's responsibility to guarantee that
@@ -5681,7 +5685,8 @@
  * pages which PFN is in [start, end) are allocated for the caller and
  * need to be freed with free_contig_range().
  */
-int alloc_contig_range(unsigned long start, unsigned long end)
+int alloc_contig_range(unsigned long start, unsigned long end,
+		       unsigned migratetype)
 {
 	struct zone *zone = page_zone(pfn_to_page(start));
 	unsigned long outer_start, outer_end;
@@ -5712,7 +5717,7 @@
 	 */
 
 	ret = start_isolate_page_range(pfn_max_align_down(start),
-				       pfn_max_align_up(end));
+				       pfn_max_align_up(end), migratetype);
 	if (ret)
 		goto done;
 
@@ -5772,7 +5777,7 @@
 
 done:
 	undo_isolate_page_range(pfn_max_align_down(start),
-				pfn_max_align_up(end));
+				pfn_max_align_up(end), migratetype);
 	return ret;
 }