[PATCH 2/2] zram: clear trailing bytes of compressed writeback pages

[Sergey Senozhatsky]

When compressed writeback is available writtenback pages
contain garbage PAGE_SIZE - obj_size trailing bytes. Zero
out those trailing bytes before writeback to a backing
device.

Suggested-by: Brian Geffon <bgeffon@xxxxxxxxxx>
Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
---
 drivers/block/zram/zram_drv.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 602abfe23797..7917fc7a2a29 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -2134,6 +2134,8 @@ static int read_from_zspool_raw(struct zram *zram, struct page *page, u32 index)
 	zs_obj_read_end(zram->mem_pool, handle, size, src);
 	zcomp_stream_put(zstrm);
 
+	memzero_page(page, size, PAGE_SIZE - size);
+
 	return 0;
 }
 #endif
-- 
2.54.0.746.g67dd491aae-goog