nvme: Use blk_rq_map_user_io helper

User blk_rq_map_user_io instead of duplicating the same code at
different places
Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
Link: https://lore.kernel.org/r/20220930062749.152261-6-anuj20.g@samsung.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/nvme/host/ioctl.c

@@ -88,22 +88,8 @@ static struct request *nvme_alloc_user_request(struct request_queue *q,
 	nvme_req(req)->flags |= NVME_REQ_USERCMD;
 
 	if (ubuffer && bufflen) {
-		if (!vec)
-			ret = blk_rq_map_user(q, req, NULL, ubuffer, bufflen,
-				GFP_KERNEL);
-		else {
-			struct iovec fast_iov[UIO_FASTIOV];
-			struct iovec *iov = fast_iov;
-			struct iov_iter iter;
-
-			ret = import_iovec(rq_data_dir(req), ubuffer, bufflen,
-					UIO_FASTIOV, &iov, &iter);
-			if (ret < 0)
-				goto out;
-			ret = blk_rq_map_user_iov(q, req, NULL, &iter,
-					GFP_KERNEL);
-			kfree(iov);
-		}
+		ret = blk_rq_map_user_io(req, NULL, ubuffer, bufflen,
+				GFP_KERNEL, vec, 0, 0, rq_data_dir(req));
 		if (ret)
 			goto out;
 		bio = req->bio;