From fea85cff11de4377040deff0e85eb2793fb078aa Mon Sep 17 00:00:00 2001
From: Joonsoo Kim <js1304@gmail.com>
Date: Thu, 14 Jan 2016 15:18:39 -0800
Subject: [PATCH] mm/page_isolation.c: return last tested pfn rather than
 failure indicator

This is preparation step to report test failed pfn in new tracepoint to
analyze cma allocation failure problem.  There is no functional change
in this patch.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Cc: Minchan Kim <minchan@kernel.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 mm/page_isolation.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 4568fd58f70a0..029a171d35dcb 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -212,7 +212,7 @@ int undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
  *
  * Returns 1 if all pages in the range are isolated.
  */
-static int
+static unsigned long
 __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn,
 				  bool skip_hwpoisoned_pages)
 {
@@ -237,9 +237,8 @@ __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn,
 		else
 			break;
 	}
-	if (pfn < end_pfn)
-		return 0;
-	return 1;
+
+	return pfn;
 }
 
 int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn,
@@ -248,7 +247,6 @@ int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn,
 	unsigned long pfn, flags;
 	struct page *page;
 	struct zone *zone;
-	int ret;
 
 	/*
 	 * Note: pageblock_nr_pages != MAX_ORDER. Then, chunks of free pages
@@ -266,10 +264,11 @@ int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn,
 	/* Check all pages are free or marked as ISOLATED */
 	zone = page_zone(page);
 	spin_lock_irqsave(&zone->lock, flags);
-	ret = __test_page_isolated_in_pageblock(start_pfn, end_pfn,
+	pfn = __test_page_isolated_in_pageblock(start_pfn, end_pfn,
 						skip_hwpoisoned_pages);
 	spin_unlock_irqrestore(&zone->lock, flags);
-	return ret ? 0 : -EBUSY;
+
+	return pfn < end_pfn ? -EBUSY : 0;
 }
 
 struct page *alloc_migrate_target(struct page *page, unsigned long private,
-- 
GitLab