[PATCH] mm/balloon_compaction: fix deflation when compaction is disabled

[Konstantin Khlebnikov <k.khlebnikov@samsung.com>]

Fix for commit d6d86c0a7f8ddc5b38cf089222cb1d9540762dc2
("mm/balloon_compaction: redesign ballooned pages management").

If CONFIG_BALLOON_COMPACTION=n balloon_page_insert() does not link
pages with balloon and doesn't set PagePrivate flag, as a result
balloon_page_dequeue cannot get any pages because it thinks that
all of them are isolated. Without balloon compaction nobody can
isolate ballooned pages, it's safe to remove this check.

Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
Reported-by: Matt Mullins <mmullins@mmlx.us>
Cc: Stable <stable@vger.kernel.org>	(v3.17)
---
 mm/balloon_compaction.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c
index b3cbe19..fcad832 100644
--- a/mm/balloon_compaction.c
+++ b/mm/balloon_compaction.c
@@ -68,11 +68,13 @@ struct page *balloon_page_dequeue(struct balloon_dev_info *b_dev_info)
 		 * to be released by the balloon driver.
 		 */
 		if (trylock_page(page)) {
+#ifdef CONFIG_BALLOON_COMPACTION
 			if (!PagePrivate(page)) {
 				/* raced with isolation */
 				unlock_page(page);
 				continue;
 			}
+#endif
 			spin_lock_irqsave(&b_dev_info->pages_lock, flags);
 			balloon_page_delete(page);
 			__count_vm_event(BALLOON_DEFLATE);

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