IB/mlx5: Move IB event processing onto a workqueue

Because mlx5_ib_event can be called from atomic context move event
handling onto a workqueue. A mutex lock is required to get the IB device
for slave ports, so move event processing onto a work queue. When an IB
event is received, check if the mlx5_core_dev  is a slave port, if so
attempt to get the IB device it's affiliated with. If found process the
event for that device, otherwise return.

Signed-off-by: Daniel Jurgens <danielj@mellanox.com>
Reviewed-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/mlx5/main.c

@@ -70,10 +70,19 @@ static char mlx5_version[] =
 	DRIVER_NAME ": Mellanox Connect-IB Infiniband driver v"
 	DRIVER_VERSION "\n";
 
+struct mlx5_ib_event_work {
+	struct work_struct	work;
+	struct mlx5_core_dev	*dev;
+	void			*context;
+	enum mlx5_dev_event	event;
+	unsigned long		param;
+};
+
 enum {
 	MLX5_ATOMIC_SIZE_QP_8BYTES = 1 << 3,
 };
 
+static struct workqueue_struct *mlx5_ib_event_wq;
 static LIST_HEAD(mlx5_ib_unaffiliated_port_list);
 static LIST_HEAD(mlx5_ib_dev_list);
 /*
@@ -3132,15 +3141,24 @@ static void delay_drop_handler(struct work_struct *work)
 	mutex_unlock(&delay_drop->lock);
 }
 
-static void mlx5_ib_event(struct mlx5_core_dev *dev, void *context,
+static void mlx5_ib_handle_event(struct work_struct *_work)
-			  enum mlx5_dev_event event, unsigned long param)
 {
-	struct mlx5_ib_dev *ibdev = (struct mlx5_ib_dev *)context;
+	struct mlx5_ib_event_work *work =
+		container_of(_work, struct mlx5_ib_event_work, work);
+	struct mlx5_ib_dev *ibdev;
 	struct ib_event ibev;
 	bool fatal = false;
 	u8 port = 0;
 
-	switch (event) {
+	if (mlx5_core_is_mp_slave(work->dev)) {
+		ibdev = mlx5_ib_get_ibdev_from_mpi(work->context);
+		if (!ibdev)
+			goto out;
+	} else {
+		ibdev = work->context;
+	}
+
+	switch (work->event) {
 	case MLX5_DEV_EVENT_SYS_ERROR:
 		ibev.event = IB_EVENT_DEVICE_FATAL;
 		mlx5_ib_handle_internal_error(ibdev);
@@ -3150,39 +3168,39 @@ static void mlx5_ib_event(struct mlx5_core_dev *dev, void *context,
 	case MLX5_DEV_EVENT_PORT_UP:
 	case MLX5_DEV_EVENT_PORT_DOWN:
 	case MLX5_DEV_EVENT_PORT_INITIALIZED:
-		port = (u8)param;
+		port = (u8)work->param;
 
 		/* In RoCE, port up/down events are handled in
 		 * mlx5_netdev_event().
 		 */
 		if (mlx5_ib_port_link_layer(&ibdev->ib_dev, port) ==
 			IB_LINK_LAYER_ETHERNET)
-			return;
+			goto out;
 
-		ibev.event = (event == MLX5_DEV_EVENT_PORT_UP) ?
+		ibev.event = (work->event == MLX5_DEV_EVENT_PORT_UP) ?
 			     IB_EVENT_PORT_ACTIVE : IB_EVENT_PORT_ERR;
 		break;
 
 	case MLX5_DEV_EVENT_LID_CHANGE:
 		ibev.event = IB_EVENT_LID_CHANGE;
-		port = (u8)param;
+		port = (u8)work->param;
 		break;
 
 	case MLX5_DEV_EVENT_PKEY_CHANGE:
 		ibev.event = IB_EVENT_PKEY_CHANGE;
-		port = (u8)param;
+		port = (u8)work->param;
 
 		schedule_work(&ibdev->devr.ports[port - 1].pkey_change_work);
 		break;
 
 	case MLX5_DEV_EVENT_GUID_CHANGE:
 		ibev.event = IB_EVENT_GID_CHANGE;
-		port = (u8)param;
+		port = (u8)work->param;
 		break;
 
 	case MLX5_DEV_EVENT_CLIENT_REREG:
 		ibev.event = IB_EVENT_CLIENT_REREGISTER;
-		port = (u8)param;
+		port = (u8)work->param;
 		break;
 	case MLX5_DEV_EVENT_DELAY_DROP_TIMEOUT:
 		schedule_work(&ibdev->delay_drop.delay_drop_work);
@@ -3204,9 +3222,29 @@ static void mlx5_ib_event(struct mlx5_core_dev *dev, void *context,
 
 	if (fatal)
 		ibdev->ib_active = false;
-
 out:
-	return;
+	kfree(work);
+}
+
+static void mlx5_ib_event(struct mlx5_core_dev *dev, void *context,
+			  enum mlx5_dev_event event, unsigned long param)
+{
+	struct mlx5_ib_event_work *work;
+
+	work = kmalloc(sizeof(*work), GFP_ATOMIC);
+	if (work) {
+		INIT_WORK(&work->work, mlx5_ib_handle_event);
+		work->dev = dev;
+		work->param = param;
+		work->context = context;
+		work->event = event;
+
+		queue_work(mlx5_ib_event_wq, &work->work);
+		return;
+	}
+
+	dev_warn(&dev->pdev->dev, "%s: mlx5_dev_event: %d, with param: %lu dropped, couldn't allocate memory.\n",
+		 __func__, event, param);
 }
 
 static int set_has_smi_cap(struct mlx5_ib_dev *dev)
@@ -4917,6 +4955,10 @@ static int __init mlx5_ib_init(void)
 {
 	int err;
 
+	mlx5_ib_event_wq = alloc_ordered_workqueue("mlx5_ib_event_wq", 0);
+	if (!mlx5_ib_event_wq)
+		return -ENOMEM;
+
 	mlx5_ib_odp_init();
 
 	err = mlx5_register_interface(&mlx5_ib_interface);
@@ -4927,6 +4969,7 @@ static int __init mlx5_ib_init(void)
 static void __exit mlx5_ib_cleanup(void)
 {
 	mlx5_unregister_interface(&mlx5_ib_interface);
+	destroy_workqueue(mlx5_ib_event_wq);
 }
 
 module_init(mlx5_ib_init);