Revert "mm: compaction: handle incorrect MIGRATE_UNMOVABLE type pageblocks"

This reverts commit 5ceb9ce6fe9462a298bb2cd5c9f1ca6cb80a0199.

That commit seems to be the cause of the mm compation list corruption
issues that Dave Jones reported.  The locking (or rather, absense
there-of) is dubious, as is the use of the 'page' variable once it has
been found to be outside the pageblock range.

So revert it for now, we can re-visit this for 3.6.  If we even need to:
as Minchan Kim says, "The patch wasn't a bug fix and even test workload
was very theoretical".

Reported-and-tested-by: Dave Jones <davej@redhat.com>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 6092f33..4403009 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -219,7 +219,7 @@
 
 int page_group_by_mobility_disabled __read_mostly;
 
-void set_pageblock_migratetype(struct page *page, int migratetype)
+static void set_pageblock_migratetype(struct page *page, int migratetype)
 {
 
 	if (unlikely(page_group_by_mobility_disabled))
@@ -954,8 +954,8 @@
 	return pages_moved;
 }
 
-int move_freepages_block(struct zone *zone, struct page *page,
-			 int migratetype)
+static int move_freepages_block(struct zone *zone, struct page *page,
+				int migratetype)
 {
 	unsigned long start_pfn, end_pfn;
 	struct page *start_page, *end_page;
@@ -5651,7 +5651,7 @@
 		.nr_migratepages = 0,
 		.order = -1,
 		.zone = page_zone(pfn_to_page(start)),
-		.mode = COMPACT_SYNC,
+		.sync = true,
 	};
 	INIT_LIST_HEAD(&cc.migratepages);