RDMA: Allow ib_client's to fail when add() is called

When a client is added it isn't allowed to fail, but all the client's have
various failure paths within their add routines.

This creates the very fringe condition where the client was added, failed
during add and didn't set the client_data. The core code will then still
call other client_data centric ops like remove(), rename(), get_nl_info(),
and get_net_dev_by_params() with NULL client_data - which is confusing and
unexpected.

If the add() callback fails, then do not call any more client ops for the
device, even remove.

Remove all the now redundant checks for NULL client_data in ops callbacks.

Update all the add() callbacks to return error codes
appropriately. EOPNOTSUPP is used for cases where the ULP does not support
the ib_device - eg because it only works with IB.

Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Leon Romanovsky <[e-mail]>
Acked-by: Ursula Braun <[e-mail]>
Signed-off-by: Jason Gunthorpe <[e-mail]>

drivers/infiniband/core/cm.c

···
 EXPORT_SYMBOL(ibcm_reject_msg);
 
 struct cm_id_private;
-static void cm_add_one(struct ib_device *device);
+static int cm_add_one(struct ib_device *device);
 static void cm_remove_one(struct ib_device *device, void *client_data);
 static int cm_send_sidr_rep_locked(struct cm_id_private *cm_id_priv,
 				   struct ib_cm_sidr_rep_param *param);
···
 
 }
 
-static void cm_add_one(struct ib_device *ib_device)
+static int cm_add_one(struct ib_device *ib_device)
 {
 	struct cm_device *cm_dev;
 	struct cm_port *port;
···
 	cm_dev = kzalloc(struct_size(cm_dev, port, ib_device->phys_port_cnt),
 			 GFP_KERNEL);
 	if (!cm_dev)
-		return;
+		return -ENOMEM;
 
 	cm_dev->ib_device = ib_device;
 	cm_dev->ack_delay = ib_device->attrs.local_ca_ack_delay;
···
 			continue;
 
 		port = kzalloc(sizeof *port, GFP_KERNEL);
-		if (!port)
+		if (!port) {
+			ret = -ENOMEM;
 			goto error1;
+		}
 
 		cm_dev->port[i-1] = port;
 		port->cm_dev = cm_dev;
···
 							cm_recv_handler,
 							port,
 							0);
-		if (IS_ERR(port->mad_agent))
+		if (IS_ERR(port->mad_agent)) {
+			ret = PTR_ERR(port->mad_agent);
 			goto error2;
+		}
 
 		ret = ib_modify_port(ib_device, i, 0, &port_modify);
 		if (ret)
···
 		count++;
 	}
 
-	if (!count)
+	if (!count) {
+		ret = -EOPNOTSUPP;
 		goto free;
+	}
 
 	ib_set_client_data(ib_device, &cm_client, cm_dev);
 
 	write_lock_irqsave(&cm.device_lock, flags);
 	list_add_tail(&cm_dev->list, &cm.device_list);
 	write_unlock_irqrestore(&cm.device_lock, flags);
-	return;
+	return 0;
 
 error3:
 	ib_unregister_mad_agent(port->mad_agent);
···
 	}
 free:
 	kfree(cm_dev);
+	return ret;
 }
 
 static void cm_remove_one(struct ib_device *ib_device, void *client_data)
···
 	};
 	unsigned long flags;
 	int i;
-
-	if (!cm_dev)
-		return;
 
 	write_lock_irqsave(&cm.device_lock, flags);
 	list_del(&cm_dev->list);

drivers/infiniband/core/cma.c

···
 }
 EXPORT_SYMBOL(rdma_res_to_id);
 
-static void cma_add_one(struct ib_device *device);
+static int cma_add_one(struct ib_device *device);
 static void cma_remove_one(struct ib_device *device, void *client_data);
 
 static struct ib_client cma_client = {
···
 	.notifier_call = cma_netdev_callback
 };
 
-static void cma_add_one(struct ib_device *device)
+static int cma_add_one(struct ib_device *device)
 {
 	struct cma_device *cma_dev;
 	struct rdma_id_private *id_priv;
 	unsigned int i;
 	unsigned long supported_gids = 0;
+	int ret;
 
 	cma_dev = kmalloc(sizeof *cma_dev, GFP_KERNEL);
 	if (!cma_dev)
-		return;
+		return -ENOMEM;
 
 	cma_dev->device = device;
 	cma_dev->default_gid_type = kcalloc(device->phys_port_cnt,
 					    sizeof(*cma_dev->default_gid_type),
 					    GFP_KERNEL);
-	if (!cma_dev->default_gid_type)
+	if (!cma_dev->default_gid_type) {
+		ret = -ENOMEM;
 		goto free_cma_dev;
+	}
 
 	cma_dev->default_roce_tos = kcalloc(device->phys_port_cnt,
 					    sizeof(*cma_dev->default_roce_tos),
 					    GFP_KERNEL);
-	if (!cma_dev->default_roce_tos)
+	if (!cma_dev->default_roce_tos) {
+		ret = -ENOMEM;
 		goto free_gid_type;
+	}
 
 	rdma_for_each_port (device, i) {
 		supported_gids = roce_gid_type_mask_support(device, i);
···
 	mutex_unlock(&lock);
 
 	trace_cm_add_one(device);
-	return;
+	return 0;
 
 free_gid_type:
 	kfree(cma_dev->default_gid_type);
 
 free_cma_dev:
 	kfree(cma_dev);
-
-	return;
+	return ret;
 }
 
 static int cma_remove_id_dev(struct rdma_id_private *id_priv)
···
 	struct cma_device *cma_dev = client_data;
 
 	trace_cm_remove_one(device);
-
-	if (!cma_dev)
-		return;
 
 	mutex_lock(&lock);
 	list_del(&cma_dev->list);

drivers/infiniband/core/device.c

···
 	if (ret)
 		goto out;
 	downgrade_write(&device->client_data_rwsem);
-	if (client->add)
-		client->add(device);
+	if (client->add) {
+		if (client->add(device)) {
+			/*
+			 * If a client fails to add then the error code is
+			 * ignored, but we won't call any more ops on this
+			 * client.
+			 */
+			xa_erase(&device->client_data, client->client_id);
+			up_read(&device->client_data_rwsem);
+			ib_device_put(device);
+			ib_client_put(client);
+			return 0;
+		}
+	}
 
 	/* Readers shall not see a client until add has been completed */
 	xa_set_mark(&device->client_data, client->client_id,

drivers/infiniband/core/mad.c

···
 	return 0;
 }
 
-static void ib_mad_init_device(struct ib_device *device)
+static int ib_mad_init_device(struct ib_device *device)
 {
 	int start, i;
+	unsigned int count = 0;
+	int ret;
 
 	start = rdma_start_port(device);
 
···
 		if (!rdma_cap_ib_mad(device, i))
 			continue;
 
-		if (ib_mad_port_open(device, i)) {
+		ret = ib_mad_port_open(device, i);
+		if (ret) {
 			dev_err(&device->dev, "Couldn't open port %d\n", i);
 			goto error;
 		}
-		if (ib_agent_port_open(device, i)) {
+		ret = ib_agent_port_open(device, i);
+		if (ret) {
 			dev_err(&device->dev,
 				"Couldn't open port %d for agents\n", i);
 			goto error_agent;
 		}
+		count++;
 	}
-	return;
+	if (!count)
+		return -EOPNOTSUPP;
+
+	return 0;
 
 error_agent:
 	if (ib_mad_port_close(device, i))
···
 		if (ib_mad_port_close(device, i))
 			dev_err(&device->dev, "Couldn't close port %d\n", i);
 	}
+	return ret;
 }
 
 static void ib_mad_remove_device(struct ib_device *device, void *client_data)

drivers/infiniband/core/multicast.c

···
 #include <rdma/ib_cache.h>
 #include "sa.h"
 
-static void mcast_add_one(struct ib_device *device);
+static int mcast_add_one(struct ib_device *device);
 static void mcast_remove_one(struct ib_device *device, void *client_data);
 
 static struct ib_client mcast_client = {
···
 	}
 }
 
-static void mcast_add_one(struct ib_device *device)
+static int mcast_add_one(struct ib_device *device)
 {
 	struct mcast_device *dev;
 	struct mcast_port *port;
···
 	dev = kmalloc(struct_size(dev, port, device->phys_port_cnt),
 		      GFP_KERNEL);
 	if (!dev)
-		return;
+		return -ENOMEM;
 
 	dev->start_port = rdma_start_port(device);
 	dev->end_port = rdma_end_port(device);
···
 
 	if (!count) {
 		kfree(dev);
-		return;
+		return -EOPNOTSUPP;
 	}
 
 	dev->device = device;
···
 
 	INIT_IB_EVENT_HANDLER(&dev->event_handler, device, mcast_event_handler);
 	ib_register_event_handler(&dev->event_handler);
+	return 0;
 }
 
 static void mcast_remove_one(struct ib_device *device, void *client_data)
···
 	struct mcast_device *dev = client_data;
 	struct mcast_port *port;
 	int i;
-
-	if (!dev)
-		return;
 
 	ib_unregister_event_handler(&dev->event_handler);
 	flush_workqueue(mcast_wq);

drivers/infiniband/core/sa_query.c

···
 };
 
 
-static void ib_sa_add_one(struct ib_device *device);
+static int ib_sa_add_one(struct ib_device *device);
 static void ib_sa_remove_one(struct ib_device *device, void *client_data);
 
 static struct ib_client sa_client = {
···
 	}
 }
 
-static void ib_sa_add_one(struct ib_device *device)
+static int ib_sa_add_one(struct ib_device *device)
 {
 	struct ib_sa_device *sa_dev;
 	int s, e, i;
 	int count = 0;
+	int ret;
 
 	s = rdma_start_port(device);
 	e = rdma_end_port(device);
 
 	sa_dev = kzalloc(struct_size(sa_dev, port, e - s + 1), GFP_KERNEL);
 	if (!sa_dev)
-		return;
+		return -ENOMEM;
 
 	sa_dev->start_port = s;
 	sa_dev->end_port   = e;
···
 			ib_register_mad_agent(device, i + s, IB_QPT_GSI,
 					      NULL, 0, send_handler,
 					      recv_handler, sa_dev, 0);
-		if (IS_ERR(sa_dev->port[i].agent))
+		if (IS_ERR(sa_dev->port[i].agent)) {
+			ret = PTR_ERR(sa_dev->port[i].agent);
 			goto err;
+		}
 
 		INIT_WORK(&sa_dev->port[i].update_task, update_sm_ah);
 		INIT_DELAYED_WORK(&sa_dev->port[i].ib_cpi_work,
···
 		count++;
 	}
 
-	if (!count)
+	if (!count) {
+		ret = -EOPNOTSUPP;
 		goto free;
+	}
 
 	ib_set_client_data(device, &sa_client, sa_dev);
 
···
 			update_sm_ah(&sa_dev->port[i].update_task);
 	}
 
-	return;
+	return 0;
 
 err:
 	while (--i >= 0) {
···
 	}
 free:
 	kfree(sa_dev);
-	return;
+	return ret;
 }
 
 static void ib_sa_remove_one(struct ib_device *device, void *client_data)
 {
 	struct ib_sa_device *sa_dev = client_data;
 	int i;
-
-	if (!sa_dev)
-		return;
 
 	ib_unregister_event_handler(&sa_dev->event_handler);
 	flush_workqueue(ib_wq);

drivers/infiniband/core/user_mad.c

···
 
 static DEFINE_IDA(umad_ida);
 
-static void ib_umad_add_one(struct ib_device *device);
+static int ib_umad_add_one(struct ib_device *device);
 static void ib_umad_remove_one(struct ib_device *device, void *client_data);
 
 static void ib_umad_dev_free(struct kref *kref)
···
 	put_device(&port->dev);
 }
 
-static void ib_umad_add_one(struct ib_device *device)
+static int ib_umad_add_one(struct ib_device *device)
 {
 	struct ib_umad_device *umad_dev;
 	int s, e, i;
 	int count = 0;
+	int ret;
 
 	s = rdma_start_port(device);
 	e = rdma_end_port(device);
 
 	umad_dev = kzalloc(struct_size(umad_dev, ports, e - s + 1), GFP_KERNEL);
 	if (!umad_dev)
-		return;
+		return -ENOMEM;
 
 	kref_init(&umad_dev->kref);
 	for (i = s; i <= e; ++i) {
 		if (!rdma_cap_ib_mad(device, i))
 			continue;
 
-		if (ib_umad_init_port(device, i, umad_dev,
-				      &umad_dev->ports[i - s]))
+		ret = ib_umad_init_port(device, i, umad_dev,
+					&umad_dev->ports[i - s]);
+		if (ret)
 			goto err;
 
 		count++;
 	}
 
-	if (!count)
+	if (!count) {
+		ret = -EOPNOTSUPP;
 		goto free;
+	}
 
 	ib_set_client_data(device, &umad_client, umad_dev);
 
-	return;
+	return 0;
 
 err:
 	while (--i >= s) {
···
 free:
 	/* balances kref_init */
 	ib_umad_dev_put(umad_dev);
+	return ret;
 }
 
 static void ib_umad_remove_one(struct ib_device *device, void *client_data)
 {
 	struct ib_umad_device *umad_dev = client_data;
 	unsigned int i;
-
-	if (!umad_dev)
-		return;
 
 	rdma_for_each_port (device, i) {
 		if (rdma_cap_ib_mad(device, i))

drivers/infiniband/core/uverbs_main.c

···
 static struct class *uverbs_class;
 
 static DEFINE_IDA(uverbs_ida);
-static void ib_uverbs_add_one(struct ib_device *device);
+static int ib_uverbs_add_one(struct ib_device *device);
 static void ib_uverbs_remove_one(struct ib_device *device, void *client_data);
 
 /*
···
 	return 0;
 }
 
-static void ib_uverbs_add_one(struct ib_device *device)
+static int ib_uverbs_add_one(struct ib_device *device)
 {
 	int devnum;
 	dev_t base;
···
 	int ret;
 
 	if (!device->ops.alloc_ucontext)
-		return;
+		return -EOPNOTSUPP;
 
 	uverbs_dev = kzalloc(sizeof(*uverbs_dev), GFP_KERNEL);
 	if (!uverbs_dev)
-		return;
+		return -ENOMEM;
 
 	ret = init_srcu_struct(&uverbs_dev->disassociate_srcu);
 	if (ret) {
 		kfree(uverbs_dev);
-		return;
+		return -ENOMEM;
 	}
 
 	device_initialize(&uverbs_dev->dev);
···
 
 	devnum = ida_alloc_max(&uverbs_ida, IB_UVERBS_MAX_DEVICES - 1,
 			       GFP_KERNEL);
-	if (devnum < 0)
+	if (devnum < 0) {
+		ret = -ENOMEM;
 		goto err;
+	}
 	uverbs_dev->devnum = devnum;
 	if (devnum >= IB_UVERBS_NUM_FIXED_MINOR)
 		base = dynamic_uverbs_dev + devnum - IB_UVERBS_NUM_FIXED_MINOR;
 	else
 		base = IB_UVERBS_BASE_DEV + devnum;
 
-	if (ib_uverbs_create_uapi(device, uverbs_dev))
+	ret = ib_uverbs_create_uapi(device, uverbs_dev);
+	if (ret)
 		goto err_uapi;
 
 	uverbs_dev->dev.devt = base;
···
 		goto err_uapi;
 
 	ib_set_client_data(device, &uverbs_client, uverbs_dev);
-	return;
+	return 0;
 
 err_uapi:
 	ida_free(&uverbs_ida, devnum);
···
 		ib_uverbs_comp_dev(uverbs_dev);
 	wait_for_completion(&uverbs_dev->comp);
 	put_device(&uverbs_dev->dev);
-	return;
+	return ret;
 }
 
 static void ib_uverbs_free_hw_resources(struct ib_uverbs_device *uverbs_dev,
···
 {
 	struct ib_uverbs_device *uverbs_dev = client_data;
 	int wait_clients = 1;
-
-	if (!uverbs_dev)
-		return;
 
 	cdev_device_del(&uverbs_dev->cdev, &uverbs_dev->dev);
 	ida_free(&uverbs_ida, uverbs_dev->devnum);

drivers/infiniband/ulp/ipoib/ipoib_main.c

···
 
 struct ib_sa_client ipoib_sa_client;
 
-static void ipoib_add_one(struct ib_device *device);
+static int ipoib_add_one(struct ib_device *device);
 static void ipoib_remove_one(struct ib_device *device, void *client_data);
 static void ipoib_neigh_reclaim(struct rcu_head *rp);
 static struct net_device *ipoib_get_net_dev_by_params(
···
 
 	ret = ib_find_cached_pkey(dev, port, pkey, &pkey_index);
 	if (ret)
-		return NULL;
-
-	if (!dev_list)
 		return NULL;
 
 	/* See if we can find a unique device matching the L2 parameters */
···
 	return ERR_PTR(-ENOMEM);
 }
 
-static void ipoib_add_one(struct ib_device *device)
+static int ipoib_add_one(struct ib_device *device)
 {
 	struct list_head *dev_list;
 	struct net_device *dev;
···
 
 	dev_list = kmalloc(sizeof(*dev_list), GFP_KERNEL);
 	if (!dev_list)
-		return;
+		return -ENOMEM;
 
 	INIT_LIST_HEAD(dev_list);
 
···
 
 	if (!count) {
 		kfree(dev_list);
-		return;
+		return -EOPNOTSUPP;
 	}
 
 	ib_set_client_data(device, &ipoib_client, dev_list);
+	return 0;
 }
 
 static void ipoib_remove_one(struct ib_device *device, void *client_data)
 {
 	struct ipoib_dev_priv *priv, *tmp, *cpriv, *tcpriv;
 	struct list_head *dev_list = client_data;
-
-	if (!dev_list)
-		return;
 
 	list_for_each_entry_safe(priv, tmp, dev_list, list) {
 		LIST_HEAD(head);

drivers/infiniband/ulp/opa_vnic/opa_vnic_vema.c

···
 	struct mutex                    lock;
 };
 
-static void opa_vnic_vema_add_one(struct ib_device *device);
+static int opa_vnic_vema_add_one(struct ib_device *device);
 static void opa_vnic_vema_rem_one(struct ib_device *device,
 				  void *client_data);
 
···
  *
  * Allocate the vnic control port and initialize it.
  */
-static void opa_vnic_vema_add_one(struct ib_device *device)
+static int opa_vnic_vema_add_one(struct ib_device *device)
 {
 	struct opa_vnic_ctrl_port *cport;
 	int rc, size = sizeof(*cport);
 
 	if (!rdma_cap_opa_vnic(device))
-		return;
+		return -EOPNOTSUPP;
 
 	size += device->phys_port_cnt * sizeof(struct opa_vnic_vema_port);
 	cport = kzalloc(size, GFP_KERNEL);
 	if (!cport)
-		return;
+		return -ENOMEM;
 
 	cport->num_ports = device->phys_port_cnt;
 	cport->ibdev = device;
···
 
 	ib_set_client_data(device, &opa_vnic_client, cport);
 	opa_vnic_ctrl_config_dev(cport, true);
+	return 0;
 }
 
 /**
···
 				  void *client_data)
 {
 	struct opa_vnic_ctrl_port *cport = client_data;
-
-	if (!cport)
-		return;
 
 	c_info("removing VNIC client\n");
 	opa_vnic_ctrl_config_dev(cport, false);

drivers/infiniband/ulp/srp/ib_srp.c

···
 MODULE_PARM_DESC(ch_count,
 		 "Number of RDMA channels to use for communication with an SRP target. Using more than one channel improves performance if the HCA supports multiple completion vectors. The default value is the minimum of four times the number of online CPU sockets and the number of completion vectors supported by the HCA.");
 
-static void srp_add_one(struct ib_device *device);
+static int srp_add_one(struct ib_device *device);
 static void srp_remove_one(struct ib_device *device, void *client_data);
 static void srp_rename_dev(struct ib_device *device, void *client_data);
 static void srp_recv_done(struct ib_cq *cq, struct ib_wc *wc);
···
 	}
 }
 
-static void srp_add_one(struct ib_device *device)
+static int srp_add_one(struct ib_device *device)
 {
 	struct srp_device *srp_dev;
 	struct ib_device_attr *attr = &device->attrs;
···
 
 	srp_dev = kzalloc(sizeof(*srp_dev), GFP_KERNEL);
 	if (!srp_dev)
-		return;
+		return -ENOMEM;
 
 	/*
 	 * Use the smallest page size supported by the HCA, down to a
···
 
 	srp_dev->dev = device;
 	srp_dev->pd  = ib_alloc_pd(device, flags);
-	if (IS_ERR(srp_dev->pd))
-		goto free_dev;
+	if (IS_ERR(srp_dev->pd)) {
+		int ret = PTR_ERR(srp_dev->pd);
+
+		kfree(srp_dev);
+		return ret;
+	}
 
 	if (flags & IB_PD_UNSAFE_GLOBAL_RKEY) {
 		srp_dev->global_rkey = srp_dev->pd->unsafe_global_rkey;
···
 	}
 
 	ib_set_client_data(device, &srp_client, srp_dev);
-	return;
-
-free_dev:
-	kfree(srp_dev);
+	return 0;
 }
 
 static void srp_remove_one(struct ib_device *device, void *client_data)
···
 	struct srp_target_port *target;
 
 	srp_dev = client_data;
-	if (!srp_dev)
-		return;
 
 	list_for_each_entry_safe(host, tmp_host, &srp_dev->dev_list, list) {
 		device_unregister(&host->dev);

drivers/infiniband/ulp/srpt/ib_srpt.c

···
  * srpt_add_one - InfiniBand device addition callback function
  * @device: Describes a HCA.
  */
-static void srpt_add_one(struct ib_device *device)
+static int srpt_add_one(struct ib_device *device)
 {
 	struct srpt_device *sdev;
 	struct srpt_port *sport;
···
 	sdev = kzalloc(struct_size(sdev, port, device->phys_port_cnt),
 		       GFP_KERNEL);
 	if (!sdev)
-		goto err;
+		return -ENOMEM;
 
 	sdev->device = device;
 	mutex_init(&sdev->sdev_mutex);
 
 	sdev->pd = ib_alloc_pd(device, 0);
-	if (IS_ERR(sdev->pd))
+	if (IS_ERR(sdev->pd)) {
+		ret = PTR_ERR(sdev->pd);
 		goto free_dev;
+	}
 
 	sdev->lkey = sdev->pd->local_dma_lkey;
 
···
 	if (IS_ERR(sdev->cm_id)) {
 		pr_info("ib_create_cm_id() failed: %ld\n",
 			PTR_ERR(sdev->cm_id));
+		ret = PTR_ERR(sdev->cm_id);
 		sdev->cm_id = NULL;
 		if (!rdma_cm_id)
 			goto err_ring;
···
 		mutex_init(&sport->port_gid_id.mutex);
 		INIT_LIST_HEAD(&sport->port_gid_id.tpg_list);
 
-		if (srpt_refresh_port(sport)) {
+		ret = srpt_refresh_port(sport);
+		if (ret) {
 			pr_err("MAD registration failed for %s-%d.\n",
 			       dev_name(&sdev->device->dev), i);
 			goto err_event;
···
 	list_add_tail(&sdev->list, &srpt_dev_list);
 	spin_unlock(&srpt_dev_lock);
 
-out:
 	ib_set_client_data(device, &srpt_client, sdev);
 	pr_debug("added %s.\n", dev_name(&device->dev));
-	return;
+	return 0;
 
 err_event:
 	ib_unregister_event_handler(&sdev->event_handler);
···
 	ib_dealloc_pd(sdev->pd);
 free_dev:
 	kfree(sdev);
-err:
-	sdev = NULL;
 	pr_info("%s(%s) failed.\n", __func__, dev_name(&device->dev));
-	goto out;
+	return ret;
 }
 
 /**
···
 {
 	struct srpt_device *sdev = client_data;
 	int i;
-
-	if (!sdev) {
-		pr_info("%s(%s): nothing to do.\n", __func__,
-			dev_name(&device->dev));
-		return;
-	}
 
 	srpt_unregister_mad_agent(sdev);
 

include/rdma/ib_verbs.h

···
 struct ib_client_nl_info;
 struct ib_client {
 	const char *name;
-	void (*add)   (struct ib_device *);
+	int (*add)(struct ib_device *ibdev);
 	void (*remove)(struct ib_device *, void *client_data);
 	void (*rename)(struct ib_device *dev, void *client_data);
 	int (*get_nl_info)(struct ib_device *ibdev, void *client_data,

net/rds/ib.c

···
 		queue_work(rds_wq, &rds_ibdev->free_work);
 }
 
-static void rds_ib_add_one(struct ib_device *device)
+static int rds_ib_add_one(struct ib_device *device)
 {
 	struct rds_ib_device *rds_ibdev;
 	bool has_fr, has_fmr;
+	int ret;
 
 	/* Only handle IB (no iWARP) devices */
 	if (device->node_type != RDMA_NODE_IB_CA)
-		return;
+		return -EOPNOTSUPP;
 
 	rds_ibdev = kzalloc_node(sizeof(struct rds_ib_device), GFP_KERNEL,
 				 ibdev_to_node(device));
 	if (!rds_ibdev)
-		return;
+		return -ENOMEM;
 
 	spin_lock_init(&rds_ibdev->spinlock);
 	refcount_set(&rds_ibdev->refcount, 1);
···
 	if (!rds_ibdev->vector_load) {
 		pr_err("RDS/IB: %s failed to allocate vector memory\n",
 			__func__);
+		ret = -ENOMEM;
 		goto put_dev;
 	}
 
 	rds_ibdev->dev = device;
 	rds_ibdev->pd = ib_alloc_pd(device, 0);
 	if (IS_ERR(rds_ibdev->pd)) {
+		ret = PTR_ERR(rds_ibdev->pd);
 		rds_ibdev->pd = NULL;
 		goto put_dev;
 	}
···
 						   device->dma_device,
 						   sizeof(struct rds_header),
 						   L1_CACHE_BYTES, 0);
-	if (!rds_ibdev->rid_hdrs_pool)
+	if (!rds_ibdev->rid_hdrs_pool) {
+		ret = -ENOMEM;
 		goto put_dev;
+	}
 
 	rds_ibdev->mr_1m_pool =
 		rds_ib_create_mr_pool(rds_ibdev, RDS_IB_MR_1M_POOL);
 	if (IS_ERR(rds_ibdev->mr_1m_pool)) {
+		ret = PTR_ERR(rds_ibdev->mr_1m_pool);
 		rds_ibdev->mr_1m_pool = NULL;
 		goto put_dev;
 	}
···
 	rds_ibdev->mr_8k_pool =
 		rds_ib_create_mr_pool(rds_ibdev, RDS_IB_MR_8K_POOL);
 	if (IS_ERR(rds_ibdev->mr_8k_pool)) {
+		ret = PTR_ERR(rds_ibdev->mr_8k_pool);
 		rds_ibdev->mr_8k_pool = NULL;
 		goto put_dev;
 	}
···
 	refcount_inc(&rds_ibdev->refcount);
 
 	ib_set_client_data(device, &rds_ib_client, rds_ibdev);
-	refcount_inc(&rds_ibdev->refcount);
 
 	rds_ib_nodev_connect();
+	return 0;
 
 put_dev:
 	rds_ib_dev_put(rds_ibdev);
+	return ret;
 }
 
 /*
···
 static void rds_ib_remove_one(struct ib_device *device, void *client_data)
 {
 	struct rds_ib_device *rds_ibdev = client_data;
-
-	if (!rds_ibdev)
-		return;
 
 	rds_ib_dev_shutdown(rds_ibdev);
 

net/smc/smc_ib.c

···
 static struct ib_client smc_ib_client;
 
 /* callback function for ib_register_client() */
-static void smc_ib_add_dev(struct ib_device *ibdev)
+static int smc_ib_add_dev(struct ib_device *ibdev)
 {
 	struct smc_ib_device *smcibdev;
 	u8 port_cnt;
 	int i;
 
 	if (ibdev->node_type != RDMA_NODE_IB_CA)
-		return;
+		return -EOPNOTSUPP;
 
 	smcibdev = kzalloc(sizeof(*smcibdev), GFP_KERNEL);
 	if (!smcibdev)
-		return;
+		return -ENOMEM;
 
 	smcibdev->ibdev = ibdev;
 	INIT_WORK(&smcibdev->port_event_work, smc_ib_port_event_work);
···
 				       smcibdev->pnetid[i]);
 	}
 	schedule_work(&smcibdev->port_event_work);
+	return 0;
 }
 
 /* callback function for ib_unregister_client() */
···
 {
 	struct smc_ib_device *smcibdev = client_data;
 
-	if (!smcibdev || smcibdev->ibdev != ibdev)
-		return;
-	ib_set_client_data(ibdev, &smc_ib_client, NULL);
 	spin_lock(&smc_ib_devices.lock);
 	list_del_init(&smcibdev->list); /* remove from smc_ib_devices */
 	spin_unlock(&smc_ib_devices.lock);