[PATCH v2] mm/compaction: Rename 'start_pfn' to 'iteration_start_pfn' in compact_zone()

[yanfei.xu@windriver.com]

From: Yanfei Xu <yanfei.xu@windriver.com>

There are two 'start_pfn' declared in compact_zone() which have
different meaning. Rename the second one to 'iteration_start_pfn'
to prevent trace_mm_compaction_end() from tracing an undesirable
value.

BTW, remove an useless semicolon.

Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Yanfei Xu <yanfei.xu@windriver.com>
---
v1->v2:
Rename 'start_pfn' to 'iteration_start_pfn' and change commit messages.

 mm/compaction.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/mm/compaction.c b/mm/compaction.c
index 176dcded298e..ccd27c739fd6 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -2272,7 +2272,7 @@ compact_zone(struct compact_control *cc, struct capture_control *capc)
 
 	while ((ret = compact_finished(cc)) == COMPACT_CONTINUE) {
 		int err;
-		unsigned long start_pfn = cc->migrate_pfn;
+		unsigned long iteration_start_pfn = cc->migrate_pfn;
 
 		/*
 		 * Avoid multiple rescans which can happen if a page cannot be
@@ -2284,7 +2284,7 @@ compact_zone(struct compact_control *cc, struct capture_control *capc)
 		 */
 		cc->rescan = false;
 		if (pageblock_start_pfn(last_migrated_pfn) ==
-		    pageblock_start_pfn(start_pfn)) {
+		    pageblock_start_pfn(iteration_start_pfn)) {
 			cc->rescan = true;
 		}
 
@@ -2308,8 +2308,7 @@ compact_zone(struct compact_control *cc, struct capture_control *capc)
 			goto check_drain;
 		case ISOLATE_SUCCESS:
 			update_cached = false;
-			last_migrated_pfn = start_pfn;
-			;
+			last_migrated_pfn = iteration_start_pfn;
 		}
 
 		err = migrate_pages(&cc->migratepages, compaction_alloc,
-- 
2.18.2