[PATCH v3 1/5] mm/percpu-km: clear page->private before free them

[Zi Yan]

page->private is cleared in free page path. In a subsequent commit,
tail_page->private will be checked and ensured to be zero. Clearing
percpu-km allocated pages' ->private to prevent triggering warnings later,
namely undo what we did in pcpu_create_chunk().

Acked-by: David Hildenbrand (Arm) <david@xxxxxxxxxx>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@xxxxxxxxxx>
Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
---
 mm/percpu-km.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/mm/percpu-km.c b/mm/percpu-km.c
index 4efa74a495cb6..7ffe84adadb9d 100644
--- a/mm/percpu-km.c
+++ b/mm/percpu-km.c
@@ -94,8 +94,15 @@ static void pcpu_destroy_chunk(struct pcpu_chunk *chunk)
 	pcpu_stats_chunk_dealloc();
 	trace_percpu_destroy_chunk(chunk->base_addr);
 
-	if (chunk->data)
+	if (chunk->data) {
+		struct page *pages = (struct page *)chunk->data;
+		int i;
+
+		/* clear chunk info from each page before free them */
+		for (i = 0; i < nr_pages; i++)
+			pcpu_set_page_chunk(pages + i, NULL);
 		__free_pages(chunk->data, order_base_2(nr_pages));
+	}
 	pcpu_free_chunk(chunk);
 }
 

-- 
2.53.0