diff --git a/block/bio.c b/block/bio.c
index 811a96796202..190446a081a2 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -630,8 +630,7 @@ struct bio *bio_kmalloc(unsigned short nr_vecs, gfp_t gfp_mask)
 
 	if (nr_vecs > BIO_MAX_INLINE_VECS)
 		return NULL;
-	return kmalloc(sizeof(*bio) + nr_vecs * sizeof(struct bio_vec),
-			gfp_mask);
+	return kmalloc(struct_size(bio, bio_vec, nr_vecs), gfp_mask);
 }
 EXPORT_SYMBOL(bio_kmalloc);