RDMA/mlx5: Rely on existence of udata to separate kernel/user flows

Instead of keeping special field to separate kernel/user create/destroy
flows, rely on existence of udata pointer. All allocation flows are
using kzalloc() and leave uninitialized pointers as NULL which makes
MLX5_QP_EMPTY and MLX5_QP_KERNEL flows to be the same.

Link: https://lore.kernel.org/r/20200427154636.381474-25-leon@kernel.org
Reviewed-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/mlx5/mlx5_ib.h

@@ -337,7 +337,6 @@ struct mlx5_ib_rwq {
 	struct ib_umem		*umem;
 	size_t			buf_size;
 	unsigned int		page_shift;
-	int			create_type;
 	struct mlx5_db		db;
 	u32			user_index;
 	u32			wqe_count;
@@ -346,17 +345,6 @@ struct mlx5_ib_rwq {
 	u32			create_flags; /* Use enum mlx5_ib_wq_flags */
 };
 
-enum {
-	MLX5_QP_USER,
-	MLX5_QP_KERNEL,
-	MLX5_QP_EMPTY
-};
-
-enum {
-	MLX5_WQ_USER,
-	MLX5_WQ_KERNEL
-};
-
 struct mlx5_ib_rwq_ind_table {
 	struct ib_rwq_ind_table ib_rwq_ind_tbl;
 	u32			rqtn;
@@ -457,8 +445,6 @@ struct mlx5_ib_qp {
 	 */
 	int			bfregn;
 
-	int			create_type;
-
 	struct list_head	qps_list;
 	struct list_head	cq_recv_list;
 	struct list_head	cq_send_list;

drivers/infiniband/hw/mlx5/qp.c

@@ -897,7 +897,6 @@ static int create_user_rq(struct mlx5_ib_dev *dev, struct ib_pd *pd,
 		goto err_umem;
 	}
 
-	rwq->create_type = MLX5_WQ_USER;
 	return 0;
 
 err_umem:
@@ -1022,7 +1021,6 @@ static int create_user_qp(struct mlx5_ib_dev *dev, struct ib_pd *pd,
 		mlx5_ib_dbg(dev, "copy failed\n");
 		goto err_unmap;
 	}
-	qp->create_type = MLX5_QP_USER;
 
 	return 0;
 
@@ -1187,7 +1185,6 @@ static int create_kernel_qp(struct mlx5_ib_dev *dev,
 		err = -ENOMEM;
 		goto err_wrid;
 	}
-	qp->create_type = MLX5_QP_KERNEL;
 
 	return 0;
 
@@ -1214,8 +1211,10 @@ static void destroy_qp_kernel(struct mlx5_ib_dev *dev, struct mlx5_ib_qp *qp)
 	kvfree(qp->sq.wrid);
 	kvfree(qp->sq.wr_data);
 	kvfree(qp->rq.wrid);
-	mlx5_db_free(dev->mdev, &qp->db);
+	if (qp->db.db)
-	mlx5_frag_buf_free(dev->mdev, &qp->buf);
+		mlx5_db_free(dev->mdev, &qp->db);
+	if (qp->buf.frags)
+		mlx5_frag_buf_free(dev->mdev, &qp->buf);
 }
 
 static u32 get_rx_type(struct mlx5_ib_qp *qp, struct ib_qp_init_attr *attr)
@@ -2000,8 +1999,6 @@ static int create_qp_common(struct mlx5_ib_dev *dev, struct ib_pd *pd,
 		in = kvzalloc(inlen, GFP_KERNEL);
 		if (!in)
 			return -ENOMEM;
-
-		qp->create_type = MLX5_QP_EMPTY;
 	}
 
 	if (is_sqp(init_attr->qp_type))
@@ -2155,9 +2152,9 @@ static int create_qp_common(struct mlx5_ib_dev *dev, struct ib_pd *pd,
 	return 0;
 
 err_create:
-	if (qp->create_type == MLX5_QP_USER)
+	if (udata)
 		destroy_qp_user(dev, pd, qp, base, udata);
-	else if (qp->create_type == MLX5_QP_KERNEL)
+	else
 		destroy_qp_kernel(dev, qp);
 
 err:
@@ -2311,7 +2308,7 @@ static void destroy_qp_common(struct mlx5_ib_dev *dev, struct mlx5_ib_qp *qp,
 	if (recv_cq)
 		list_del(&qp->cq_recv_list);
 
-	if (qp->create_type == MLX5_QP_KERNEL) {
+	if (!udata) {
 		__mlx5_ib_cq_clean(recv_cq, base->mqp.qpn,
 				   qp->ibqp.srq ? to_msrq(qp->ibqp.srq) : NULL);
 		if (send_cq != recv_cq)
@@ -2331,10 +2328,10 @@ static void destroy_qp_common(struct mlx5_ib_dev *dev, struct mlx5_ib_qp *qp,
 				     base->mqp.qpn);
 	}
 
-	if (qp->create_type == MLX5_QP_KERNEL)
+	if (udata)
-		destroy_qp_kernel(dev, qp);
-	else if (qp->create_type == MLX5_QP_USER)
 		destroy_qp_user(dev, &get_pd(qp)->ibpd, qp, base, udata);
+	else
+		destroy_qp_kernel(dev, qp);
 }
 
 static int create_dct(struct ib_pd *pd, struct mlx5_ib_qp *qp,