RDMA/mlx: Calling qp event handler in workqueue context

Move the call of qp event handler from atomic to workqueue context,
so that the handler is able to block. This is needed by following
patches.
Signed-off-by: Mark Zhang <markzhang@nvidia.com>
Reviewed-by: Patrisious Haddad <phaddad@nvidia.com>
Link: https://lore.kernel.org/r/0cd17b8331e445f03942f4bb28d447f24ac5669d.1672821186.git.leonro@nvidia.comSigned-off-by: Leon Romanovsky <leon@kernel.org>

drivers/infiniband/hw/mlx4/main.c

@@ -3303,6 +3303,10 @@ static int __init mlx4_ib_init(void)
 	if (!wq)
 		return -ENOMEM;
 
+	err = mlx4_ib_qp_event_init();
+	if (err)
+		goto clean_qp_event;
+
 	err = mlx4_ib_cm_init();
 	if (err)
 		goto clean_wq;
@@ -3324,6 +3328,9 @@ static int __init mlx4_ib_init(void)
 	mlx4_ib_cm_destroy();
 
 clean_wq:
+	mlx4_ib_qp_event_cleanup();
+
+clean_qp_event:
 	destroy_workqueue(wq);
 	return err;
 }
@@ -3333,6 +3340,7 @@ static void __exit mlx4_ib_cleanup(void)
 	mlx4_unregister_interface(&mlx4_ib_interface);
 	mlx4_ib_mcg_destroy();
 	mlx4_ib_cm_destroy();
+	mlx4_ib_qp_event_cleanup();
 	destroy_workqueue(wq);
 }
 

drivers/infiniband/hw/mlx4/mlx4_ib.h

@@ -940,4 +940,7 @@ int mlx4_ib_umem_calc_optimal_mtt_size(struct ib_umem *umem, u64 start_va,
 int mlx4_ib_cm_init(void);
 void mlx4_ib_cm_destroy(void);
 
+int mlx4_ib_qp_event_init(void);
+void mlx4_ib_qp_event_cleanup(void);
+
 #endif /* MLX4_IB_H */

drivers/infiniband/hw/mlx4/qp.c

@@ -102,6 +102,14 @@ enum mlx4_ib_source_type {
 	MLX4_IB_RWQ_SRC	= 1,
 };
 
+struct mlx4_ib_qp_event_work {
+	struct work_struct work;
+	struct mlx4_qp *qp;
+	enum mlx4_event type;
+};
+
+static struct workqueue_struct *mlx4_ib_qp_event_wq;
+
 static int is_tunnel_qp(struct mlx4_ib_dev *dev, struct mlx4_ib_qp *qp)
 {
 	if (!mlx4_is_master(dev->dev))
@@ -200,50 +208,77 @@ static void stamp_send_wqe(struct mlx4_ib_qp *qp, int n)
 	}
 }
 
+static void mlx4_ib_handle_qp_event(struct work_struct *_work)
+{
+	struct mlx4_ib_qp_event_work *qpe_work =
+		container_of(_work, struct mlx4_ib_qp_event_work, work);
+	struct ib_qp *ibqp = &to_mibqp(qpe_work->qp)->ibqp;
+	struct ib_event event = {};
+
+	event.device = ibqp->device;
+	event.element.qp = ibqp;
+
+	switch (qpe_work->type) {
+	case MLX4_EVENT_TYPE_PATH_MIG:
+		event.event = IB_EVENT_PATH_MIG;
+		break;
+	case MLX4_EVENT_TYPE_COMM_EST:
+		event.event = IB_EVENT_COMM_EST;
+		break;
+	case MLX4_EVENT_TYPE_SQ_DRAINED:
+		event.event = IB_EVENT_SQ_DRAINED;
+		break;
+	case MLX4_EVENT_TYPE_SRQ_QP_LAST_WQE:
+		event.event = IB_EVENT_QP_LAST_WQE_REACHED;
+		break;
+	case MLX4_EVENT_TYPE_WQ_CATAS_ERROR:
+		event.event = IB_EVENT_QP_FATAL;
+		break;
+	case MLX4_EVENT_TYPE_PATH_MIG_FAILED:
+		event.event = IB_EVENT_PATH_MIG_ERR;
+		break;
+	case MLX4_EVENT_TYPE_WQ_INVAL_REQ_ERROR:
+		event.event = IB_EVENT_QP_REQ_ERR;
+		break;
+	case MLX4_EVENT_TYPE_WQ_ACCESS_ERROR:
+		event.event = IB_EVENT_QP_ACCESS_ERR;
+		break;
+	default:
+		pr_warn("Unexpected event type %d on QP %06x\n",
+			qpe_work->type, qpe_work->qp->qpn);
+		goto out;
+	}
+
+	ibqp->event_handler(&event, ibqp->qp_context);
+
+out:
+	mlx4_put_qp(qpe_work->qp);
+	kfree(qpe_work);
+}
+
 static void mlx4_ib_qp_event(struct mlx4_qp *qp, enum mlx4_event type)
 {
-	struct ib_event event;
 	struct ib_qp *ibqp = &to_mibqp(qp)->ibqp;
+	struct mlx4_ib_qp_event_work *qpe_work;
 
 	if (type == MLX4_EVENT_TYPE_PATH_MIG)
 		to_mibqp(qp)->port = to_mibqp(qp)->alt_port;
 
-	if (ibqp->event_handler) {
-		event.device     = ibqp->device;
-		event.element.qp = ibqp;
-		switch (type) {
-		case MLX4_EVENT_TYPE_PATH_MIG:
-			event.event = IB_EVENT_PATH_MIG;
-			break;
-		case MLX4_EVENT_TYPE_COMM_EST:
-			event.event = IB_EVENT_COMM_EST;
-			break;
-		case MLX4_EVENT_TYPE_SQ_DRAINED:
-			event.event = IB_EVENT_SQ_DRAINED;
-			break;
-		case MLX4_EVENT_TYPE_SRQ_QP_LAST_WQE:
-			event.event = IB_EVENT_QP_LAST_WQE_REACHED;
-			break;
-		case MLX4_EVENT_TYPE_WQ_CATAS_ERROR:
-			event.event = IB_EVENT_QP_FATAL;
-			break;
-		case MLX4_EVENT_TYPE_PATH_MIG_FAILED:
-			event.event = IB_EVENT_PATH_MIG_ERR;
-			break;
-		case MLX4_EVENT_TYPE_WQ_INVAL_REQ_ERROR:
-			event.event = IB_EVENT_QP_REQ_ERR;
-			break;
-		case MLX4_EVENT_TYPE_WQ_ACCESS_ERROR:
-			event.event = IB_EVENT_QP_ACCESS_ERR;
-			break;
-		default:
-			pr_warn("Unexpected event type %d "
-			       "on QP %06x\n", type, qp->qpn);
-			return;
-		}
+	if (!ibqp->event_handler)
+		goto out_no_handler;
 
-		ibqp->event_handler(&event, ibqp->qp_context);
-	}
+	qpe_work = kzalloc(sizeof(*qpe_work), GFP_ATOMIC);
+	if (!qpe_work)
+		goto out_no_handler;
+
+	qpe_work->qp = qp;
+	qpe_work->type = type;
+	INIT_WORK(&qpe_work->work, mlx4_ib_handle_qp_event);
+	queue_work(mlx4_ib_qp_event_wq, &qpe_work->work);
+	return;
+
+out_no_handler:
+	mlx4_put_qp(qp);
 }
 
 static void mlx4_ib_wq_event(struct mlx4_qp *qp, enum mlx4_event type)
@@ -4468,3 +4503,17 @@ void mlx4_ib_drain_rq(struct ib_qp *qp)
 
 	handle_drain_completion(cq, &rdrain, dev);
 }
+
+int mlx4_ib_qp_event_init(void)
+{
+	mlx4_ib_qp_event_wq = alloc_ordered_workqueue("mlx4_ib_qp_event_wq", 0);
+	if (!mlx4_ib_qp_event_wq)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void mlx4_ib_qp_event_cleanup(void)
+{
+	destroy_workqueue(mlx4_ib_qp_event_wq);
+}

drivers/infiniband/hw/mlx5/main.c

@@ -4403,6 +4403,10 @@ static int __init mlx5_ib_init(void)
 		return -ENOMEM;
 	}
 
+	ret = mlx5_ib_qp_event_init();
+	if (ret)
+		goto qp_event_err;
+
 	mlx5_ib_odp_init();
 	ret = mlx5r_rep_init();
 	if (ret)
@@ -4420,6 +4424,8 @@ static int __init mlx5_ib_init(void)
 mp_err:
 	mlx5r_rep_cleanup();
 rep_err:
+	mlx5_ib_qp_event_cleanup();
+qp_event_err:
 	destroy_workqueue(mlx5_ib_event_wq);
 	free_page((unsigned long)xlt_emergency_page);
 	return ret;
@@ -4431,6 +4437,7 @@ static void __exit mlx5_ib_cleanup(void)
 	auxiliary_driver_unregister(&mlx5r_mp_driver);
 	mlx5r_rep_cleanup();
 
+	mlx5_ib_qp_event_cleanup();
 	destroy_workqueue(mlx5_ib_event_wq);
 	free_page((unsigned long)xlt_emergency_page);
 }

drivers/infiniband/hw/mlx5/qp.c

@@ -71,6 +71,14 @@ struct mlx5_modify_raw_qp_param {
 	u32 port;
 };
 
+struct mlx5_ib_qp_event_work {
+	struct work_struct work;
+	struct mlx5_core_qp *qp;
+	int type;
+};
+
+static struct workqueue_struct *mlx5_ib_qp_event_wq;
+
 static void get_cqs(enum ib_qp_type qp_type,
 		    struct ib_cq *ib_send_cq, struct ib_cq *ib_recv_cq,
 		    struct mlx5_ib_cq **send_cq, struct mlx5_ib_cq **recv_cq);
@@ -302,51 +310,78 @@ int mlx5_ib_read_wqe_srq(struct mlx5_ib_srq *srq, int wqe_index, void *buffer,
 	return mlx5_ib_read_user_wqe_srq(srq, wqe_index, buffer, buflen, bc);
 }
 
+static void mlx5_ib_handle_qp_event(struct work_struct *_work)
+{
+	struct mlx5_ib_qp_event_work *qpe_work =
+		container_of(_work, struct mlx5_ib_qp_event_work, work);
+	struct ib_qp *ibqp = &to_mibqp(qpe_work->qp)->ibqp;
+	struct ib_event event = {};
+
+	event.device = ibqp->device;
+	event.element.qp = ibqp;
+	switch (qpe_work->type) {
+	case MLX5_EVENT_TYPE_PATH_MIG:
+		event.event = IB_EVENT_PATH_MIG;
+		break;
+	case MLX5_EVENT_TYPE_COMM_EST:
+		event.event = IB_EVENT_COMM_EST;
+		break;
+	case MLX5_EVENT_TYPE_SQ_DRAINED:
+		event.event = IB_EVENT_SQ_DRAINED;
+		break;
+	case MLX5_EVENT_TYPE_SRQ_LAST_WQE:
+		event.event = IB_EVENT_QP_LAST_WQE_REACHED;
+		break;
+	case MLX5_EVENT_TYPE_WQ_CATAS_ERROR:
+		event.event = IB_EVENT_QP_FATAL;
+		break;
+	case MLX5_EVENT_TYPE_PATH_MIG_FAILED:
+		event.event = IB_EVENT_PATH_MIG_ERR;
+		break;
+	case MLX5_EVENT_TYPE_WQ_INVAL_REQ_ERROR:
+		event.event = IB_EVENT_QP_REQ_ERR;
+		break;
+	case MLX5_EVENT_TYPE_WQ_ACCESS_ERROR:
+		event.event = IB_EVENT_QP_ACCESS_ERR;
+		break;
+	default:
+		pr_warn("mlx5_ib: Unexpected event type %d on QP %06x\n",
+			qpe_work->type, qpe_work->qp->qpn);
+		goto out;
+	}
+
+	ibqp->event_handler(&event, ibqp->qp_context);
+
+out:
+	mlx5_core_res_put(&qpe_work->qp->common);
+	kfree(qpe_work);
+}
+
 static void mlx5_ib_qp_event(struct mlx5_core_qp *qp, int type)
 {
 	struct ib_qp *ibqp = &to_mibqp(qp)->ibqp;
-	struct ib_event event;
+	struct mlx5_ib_qp_event_work *qpe_work;
 
 	if (type == MLX5_EVENT_TYPE_PATH_MIG) {
 		/* This event is only valid for trans_qps */
 		to_mibqp(qp)->port = to_mibqp(qp)->trans_qp.alt_port;
 	}
 
-	if (ibqp->event_handler) {
-		event.device     = ibqp->device;
-		event.element.qp = ibqp;
-		switch (type) {
-		case MLX5_EVENT_TYPE_PATH_MIG:
-			event.event = IB_EVENT_PATH_MIG;
-			break;
-		case MLX5_EVENT_TYPE_COMM_EST:
-			event.event = IB_EVENT_COMM_EST;
-			break;
-		case MLX5_EVENT_TYPE_SQ_DRAINED:
-			event.event = IB_EVENT_SQ_DRAINED;
-			break;
-		case MLX5_EVENT_TYPE_SRQ_LAST_WQE:
-			event.event = IB_EVENT_QP_LAST_WQE_REACHED;
-			break;
-		case MLX5_EVENT_TYPE_WQ_CATAS_ERROR:
-			event.event = IB_EVENT_QP_FATAL;
-			break;
-		case MLX5_EVENT_TYPE_PATH_MIG_FAILED:
-			event.event = IB_EVENT_PATH_MIG_ERR;
-			break;
-		case MLX5_EVENT_TYPE_WQ_INVAL_REQ_ERROR:
-			event.event = IB_EVENT_QP_REQ_ERR;
-			break;
-		case MLX5_EVENT_TYPE_WQ_ACCESS_ERROR:
-			event.event = IB_EVENT_QP_ACCESS_ERR;
-			break;
-		default:
-			pr_warn("mlx5_ib: Unexpected event type %d on QP %06x\n", type, qp->qpn);
-			return;
-		}
+	if (!ibqp->event_handler)
+		goto out_no_handler;
 
-		ibqp->event_handler(&event, ibqp->qp_context);
-	}
+	qpe_work = kzalloc(sizeof(*qpe_work), GFP_ATOMIC);
+	if (!qpe_work)
+		goto out_no_handler;
+
+	qpe_work->qp = qp;
+	qpe_work->type = type;
+	INIT_WORK(&qpe_work->work, mlx5_ib_handle_qp_event);
+	queue_work(mlx5_ib_qp_event_wq, &qpe_work->work);
+	return;
+
+out_no_handler:
+	mlx5_core_res_put(&qp->common);
 }
 
 static int set_rq_size(struct mlx5_ib_dev *dev, struct ib_qp_cap *cap,
@@ -5720,3 +5755,17 @@ int mlx5_ib_qp_set_counter(struct ib_qp *qp, struct rdma_counter *counter)
 	mutex_unlock(&mqp->mutex);
 	return err;
 }
+
+int mlx5_ib_qp_event_init(void)
+{
+	mlx5_ib_qp_event_wq = alloc_ordered_workqueue("mlx5_ib_qp_event_wq", 0);
+	if (!mlx5_ib_qp_event_wq)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void mlx5_ib_qp_event_cleanup(void)
+{
+	destroy_workqueue(mlx5_ib_qp_event_wq);
+}

drivers/infiniband/hw/mlx5/qp.h

@@ -44,4 +44,6 @@ void mlx5_core_res_put(struct mlx5_core_rsc_common *res);
 int mlx5_core_xrcd_alloc(struct mlx5_ib_dev *dev, u32 *xrcdn);
 int mlx5_core_xrcd_dealloc(struct mlx5_ib_dev *dev, u32 xrcdn);
 int mlx5_ib_qp_set_counter(struct ib_qp *qp, struct rdma_counter *counter);
+int mlx5_ib_qp_event_init(void);
+void mlx5_ib_qp_event_cleanup(void);
 #endif /* _MLX5_IB_QP_H */

drivers/infiniband/hw/mlx5/qpc.c

@@ -135,7 +135,8 @@ static int rsc_event_notifier(struct notifier_block *nb,
 	case MLX5_RES_SQ:
 		qp = (struct mlx5_core_qp *)common;
 		qp->event(qp, event_type);
-		break;
+		/* Need to put resource in event handler */
+		return NOTIFY_OK;
 	case MLX5_RES_DCT:
 		dct = (struct mlx5_core_dct *)common;
 		if (event_type == MLX5_EVENT_TYPE_DCT_DRAINED)

drivers/net/ethernet/mellanox/mlx4/qp.c

@@ -46,6 +46,13 @@
 #define MLX4_BF_QP_SKIP_MASK	0xc0
 #define MLX4_MAX_BF_QP_RANGE	0x40
 
+void mlx4_put_qp(struct mlx4_qp *qp)
+{
+	if (refcount_dec_and_test(&qp->refcount))
+		complete(&qp->free);
+}
+EXPORT_SYMBOL_GPL(mlx4_put_qp);
+
 void mlx4_qp_event(struct mlx4_dev *dev, u32 qpn, int event_type)
 {
 	struct mlx4_qp_table *qp_table = &mlx4_priv(dev)->qp_table;
@@ -64,10 +71,8 @@ void mlx4_qp_event(struct mlx4_dev *dev, u32 qpn, int event_type)
 		return;
 	}
 
+	/* Need to call mlx4_put_qp() in event handler */
 	qp->event(qp, event_type);
-
-	if (refcount_dec_and_test(&qp->refcount))
-		complete(&qp->free);
 }
 
 /* used for INIT/CLOSE port logic */
@@ -523,8 +528,7 @@ EXPORT_SYMBOL_GPL(mlx4_qp_remove);
 
 void mlx4_qp_free(struct mlx4_dev *dev, struct mlx4_qp *qp)
 {
-	if (refcount_dec_and_test(&qp->refcount))
-		complete(&qp->free);
+	mlx4_put_qp(qp);
 	wait_for_completion(&qp->free);
 
 	mlx4_qp_free_icm(dev, qp->qpn);

include/linux/mlx4/qp.h

@@ -503,4 +503,5 @@ static inline u16 folded_qp(u32 q)
 
 u16 mlx4_qp_roce_entropy(struct mlx4_dev *dev, u32 qpn);
 
+void mlx4_put_qp(struct mlx4_qp *qp);
 #endif /* MLX4_QP_H */

include/rdma/ib_verbs.h

@@ -1168,7 +1168,7 @@ enum ib_qp_create_flags {
  */
 
 struct ib_qp_init_attr {
-	/* Consumer's event_handler callback must not block */
+	/* This callback occurs in workqueue context */
 	void                  (*event_handler)(struct ib_event *, void *);
 
 	void		       *qp_context;