[PATCH v2 06/10] mm/page_isolation: simplify return value of start_isolate_page_range()

[David Hildenbrand <david@xxxxxxxxxx>]

Callers no longer need the number of isolated pageblocks. Let's
simplify.

Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Wei Yang <richard.weiyang@xxxxxxxxxxxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Cc: Pankaj Gupta <pankaj.gupta.linux@xxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
---
 mm/memory_hotplug.c | 2 +-
 mm/page_alloc.c     | 2 +-
 mm/page_isolation.c | 7 ++-----
 3 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 098361fcb4504..0011a1115381c 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1503,7 +1503,7 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages)
 	ret = start_isolate_page_range(start_pfn, end_pfn,
 				       MIGRATE_MOVABLE,
 				       MEMORY_OFFLINE | REPORT_FAILURE);
-	if (ret < 0) {
+	if (ret) {
 		reason = "failure to isolate range";
 		goto failed_removal;
 	}
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 03f585f95dc60..848664352dfe2 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -8456,7 +8456,7 @@ int alloc_contig_range(unsigned long start, unsigned long end,
 
 	ret = start_isolate_page_range(pfn_max_align_down(start),
 				       pfn_max_align_up(end), migratetype, 0);
-	if (ret < 0)
+	if (ret)
 		return ret;
 
 	/*
diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 242c03121d731..b066c860e606e 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -170,8 +170,7 @@ __first_valid_page(unsigned long pfn, unsigned long nr_pages)
  * pageblocks we may have modified and return -EBUSY to caller. This
  * prevents two threads from simultaneously working on overlapping ranges.
  *
- * Return: the number of isolated pageblocks on success and -EBUSY if any part
- * of range cannot be isolated.
+ * Return: 0 on success and -EBUSY if any part of range cannot be isolated.
  */
 int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
 			     unsigned migratetype, int flags)
@@ -179,7 +178,6 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
 	unsigned long pfn;
 	unsigned long undo_pfn;
 	struct page *page;
-	int nr_isolate_pageblock = 0;
 
 	BUG_ON(!IS_ALIGNED(start_pfn, pageblock_nr_pages));
 	BUG_ON(!IS_ALIGNED(end_pfn, pageblock_nr_pages));
@@ -193,10 +191,9 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
 				undo_pfn = pfn;
 				goto undo;
 			}
-			nr_isolate_pageblock++;
 		}
 	}
-	return nr_isolate_pageblock;
+	return 0;
 undo:
 	for (pfn = start_pfn;
 	     pfn < undo_pfn;
-- 
2.26.2