[PATCH 4.9 05/12] block-map: add __GFP_ZERO flag for alloc_page in function bio_copy_kern

[Greg Kroah-Hartman]

From: Haimin Zhang <tcs.kernel@xxxxxxxxx>

commit cc8f7fe1f5eab010191aa4570f27641876fa1267 upstream.

Add __GFP_ZERO flag for alloc_page in function bio_copy_kern to initialize
the buffer of a bio.

Signed-off-by: Haimin Zhang <tcs.kernel@xxxxxxxxx>
Reviewed-by: Chaitanya Kulkarni <kch@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Link: https://lore.kernel.org/r/20220216084038.15635-1-tcs.kernel@xxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
[DP: Backported to 4.19: Manually added __GFP_ZERO flag]
Signed-off-by: Dragos-Marian Panait <dragos.panait@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 block/bio.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/block/bio.c
+++ b/block/bio.c
@@ -1538,7 +1538,7 @@ struct bio *bio_copy_kern(struct request
 		if (bytes > len)
 			bytes = len;
 
-		page = alloc_page(q->bounce_gfp | gfp_mask);
+		page = alloc_page(q->bounce_gfp | __GFP_ZERO | gfp_mask);
 		if (!page)
 			goto cleanup;