block-map: add __GFP_ZERO flag for alloc_page in function bio_copy_kern

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

Signed-off-by: Haimin Zhang <[email protected]>
Reviewed-by: Chaitanya Kulkarni <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

Author: Haimin Zhang

block/blk-map.c

@@ -446,7 +446,7 @@ static struct bio *bio_copy_kern(struct request_queue *q, void *data,
 		if (bytes > len)
 			bytes = len;
 
-		page = alloc_page(GFP_NOIO | gfp_mask);
+		page = alloc_page(GFP_NOIO | __GFP_ZERO | gfp_mask);
 		if (!page)
 			goto cleanup;