rdma/siw: network and RDMA core interface

Broken up commit to add the Soft iWarp RDMA driver.
Signed-off-by: Bernard Metzler <bmt@zurich.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/sw/siw/siw_main.c

+// SPDX-License-Identifier: GPL-2.0 or BSD-3-Clause
+
+/* Authors: Bernard Metzler <bmt@zurich.ibm.com> */
+/* Copyright (c) 2008-2019, IBM Corporation */
+
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/netdevice.h>
+#include <linux/inetdevice.h>
+#include <net/net_namespace.h>
+#include <linux/rtnetlink.h>
+#include <linux/if_arp.h>
+#include <linux/list.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/module.h>
+#include <linux/dma-mapping.h>
+
+#include <rdma/ib_verbs.h>
+#include <rdma/ib_user_verbs.h>
+#include <rdma/rdma_netlink.h>
+#include <linux/kthread.h>
+
+#include "siw.h"
+#include "siw_verbs.h"
+
+MODULE_AUTHOR("Bernard Metzler");
+MODULE_DESCRIPTION("Software iWARP Driver");
+MODULE_LICENSE("Dual BSD/GPL");
+
+/* transmit from user buffer, if possible */
+const bool zcopy_tx = true;
+
+/* Restrict usage of GSO, if hardware peer iwarp is unable to process
+ * large packets. try_gso = true lets siw try to use local GSO,
+ * if peer agrees.  Not using GSO severly limits siw maximum tx bandwidth.
+ */
+const bool try_gso;
+
+/* Attach siw also with loopback devices */
+const bool loopback_enabled = true;
+
+/* We try to negotiate CRC on, if true */
+const bool mpa_crc_required;
+
+/* MPA CRC on/off enforced */
+const bool mpa_crc_strict;
+
+/* Control TCP_NODELAY socket option */
+const bool siw_tcp_nagle;
+
+/* Select MPA version to be used during connection setup */
+u_char mpa_version = MPA_REVISION_2;
+
+/* Selects MPA P2P mode (additional handshake during connection
+ * setup, if true.
+ */
+const bool peer_to_peer;
+
+struct task_struct *siw_tx_thread[NR_CPUS];
+struct crypto_shash *siw_crypto_shash;
+
+static int siw_device_register(struct siw_device *sdev, const char *name)
+{
+	struct ib_device *base_dev = &sdev->base_dev;
+	static int dev_id = 1;
+	int rv;
+
+	rv = ib_register_device(base_dev, name);
+	if (rv) {
+		pr_warn("siw: device registration error %d\n", rv);
+		return rv;
+	}
+	sdev->vendor_part_id = dev_id++;
+
+	siw_dbg(base_dev, "HWaddr=%pM\n", sdev->netdev->dev_addr);
+
+	return 0;
+}
+
+static void siw_device_cleanup(struct ib_device *base_dev)
+{
+	struct siw_device *sdev = to_siw_dev(base_dev);
+
+	xa_destroy(&sdev->qp_xa);
+	xa_destroy(&sdev->mem_xa);
+}
+
+static int siw_create_tx_threads(void)
+{
+	int cpu, rv, assigned = 0;
+
+	for_each_online_cpu(cpu) {
+		/* Skip HT cores */
+		if (cpu % cpumask_weight(topology_sibling_cpumask(cpu)))
+			continue;
+
+		siw_tx_thread[cpu] =
+			kthread_create(siw_run_sq, (unsigned long *)(long)cpu,
+				       "siw_tx/%d", cpu);
+		if (IS_ERR(siw_tx_thread[cpu])) {
+			rv = PTR_ERR(siw_tx_thread[cpu]);
+			siw_tx_thread[cpu] = NULL;
+			pr_info("Creating TX thread for CPU %d failed", cpu);
+			continue;
+		}
+		kthread_bind(siw_tx_thread[cpu], cpu);
+
+		wake_up_process(siw_tx_thread[cpu]);
+		assigned++;
+	}
+	return assigned;
+}
+
+static int siw_dev_qualified(struct net_device *netdev)
+{
+	/*
+	 * Additional hardware support can be added here
+	 * (e.g. ARPHRD_FDDI, ARPHRD_ATM, ...) - see
+	 * <linux/if_arp.h> for type identifiers.
+	 */
+	if (netdev->type == ARPHRD_ETHER || netdev->type == ARPHRD_IEEE802 ||
+	    (netdev->type == ARPHRD_LOOPBACK && loopback_enabled))
+		return 1;
+
+	return 0;
+}
+
+static DEFINE_PER_CPU(atomic_t, use_cnt = ATOMIC_INIT(0));
+
+static struct {
+	struct cpumask **tx_valid_cpus;
+	int num_nodes;
+} siw_cpu_info;
+
+static int siw_init_cpulist(void)
+{
+	int i, num_nodes = num_possible_nodes();
+
+	memset(siw_tx_thread, 0, sizeof(siw_tx_thread));
+
+	siw_cpu_info.num_nodes = num_nodes;
+
+	siw_cpu_info.tx_valid_cpus =
+		kcalloc(num_nodes, sizeof(struct cpumask *), GFP_KERNEL);
+	if (!siw_cpu_info.tx_valid_cpus) {
+		siw_cpu_info.num_nodes = 0;
+		return -ENOMEM;
+	}
+	for (i = 0; i < siw_cpu_info.num_nodes; i++) {
+		siw_cpu_info.tx_valid_cpus[i] =
+			kzalloc(sizeof(struct cpumask), GFP_KERNEL);
+		if (!siw_cpu_info.tx_valid_cpus[i])
+			goto out_err;
+
+		cpumask_clear(siw_cpu_info.tx_valid_cpus[i]);
+	}
+	for_each_possible_cpu(i)
+		cpumask_set_cpu(i, siw_cpu_info.tx_valid_cpus[cpu_to_node(i)]);
+
+	return 0;
+
+out_err:
+	siw_cpu_info.num_nodes = 0;
+	while (i) {
+		kfree(siw_cpu_info.tx_valid_cpus[i]);
+		siw_cpu_info.tx_valid_cpus[i--] = NULL;
+	}
+	kfree(siw_cpu_info.tx_valid_cpus);
+	siw_cpu_info.tx_valid_cpus = NULL;
+
+	return -ENOMEM;
+}
+
+static void siw_destroy_cpulist(void)
+{
+	int i = 0;
+
+	while (i < siw_cpu_info.num_nodes)
+		kfree(siw_cpu_info.tx_valid_cpus[i++]);
+
+	kfree(siw_cpu_info.tx_valid_cpus);
+}
+
+/*
+ * Choose CPU with least number of active QP's from NUMA node of
+ * TX interface.
+ */
+int siw_get_tx_cpu(struct siw_device *sdev)
+{
+	const struct cpumask *tx_cpumask;
+	int i, num_cpus, cpu, min_use, node = sdev->numa_node, tx_cpu = -1;
+
+	if (node < 0)
+		tx_cpumask = cpu_online_mask;
+	else
+		tx_cpumask = siw_cpu_info.tx_valid_cpus[node];
+
+	num_cpus = cpumask_weight(tx_cpumask);
+	if (!num_cpus) {
+		/* no CPU on this NUMA node */
+		tx_cpumask = cpu_online_mask;
+		num_cpus = cpumask_weight(tx_cpumask);
+	}
+	if (!num_cpus)
+		goto out;
+
+	cpu = cpumask_first(tx_cpumask);
+
+	for (i = 0, min_use = SIW_MAX_QP; i < num_cpus;
+	     i++, cpu = cpumask_next(cpu, tx_cpumask)) {
+		int usage;
+
+		/* Skip any cores which have no TX thread */
+		if (!siw_tx_thread[cpu])
+			continue;
+
+		usage = atomic_read(&per_cpu(use_cnt, cpu));
+		if (usage <= min_use) {
+			tx_cpu = cpu;
+			min_use = usage;
+		}
+	}
+	siw_dbg(&sdev->base_dev,
+		"tx cpu %d, node %d, %d qp's\n", tx_cpu, node, min_use);
+
+out:
+	if (tx_cpu >= 0)
+		atomic_inc(&per_cpu(use_cnt, tx_cpu));
+	else
+		pr_warn("siw: no tx cpu found\n");
+
+	return tx_cpu;
+}
+
+void siw_put_tx_cpu(int cpu)
+{
+	atomic_dec(&per_cpu(use_cnt, cpu));
+}
+
+static struct ib_qp *siw_get_base_qp(struct ib_device *base_dev, int id)
+{
+	struct siw_qp *qp = siw_qp_id2obj(to_siw_dev(base_dev), id);
+
+	if (qp) {
+		/*
+		 * siw_qp_id2obj() increments object reference count
+		 */
+		siw_qp_put(qp);
+		return qp->ib_qp;
+	}
+	return NULL;
+}
+
+static void siw_verbs_sq_flush(struct ib_qp *base_qp)
+{
+	struct siw_qp *qp = to_siw_qp(base_qp);
+
+	down_write(&qp->state_lock);
+	siw_sq_flush(qp);
+	up_write(&qp->state_lock);
+}
+
+static void siw_verbs_rq_flush(struct ib_qp *base_qp)
+{
+	struct siw_qp *qp = to_siw_qp(base_qp);
+
+	down_write(&qp->state_lock);
+	siw_rq_flush(qp);
+	up_write(&qp->state_lock);
+}
+
+static const struct ib_device_ops siw_device_ops = {
+	.owner = THIS_MODULE,
+	.uverbs_abi_ver = SIW_ABI_VERSION,
+	.driver_id = RDMA_DRIVER_SIW,
+
+	.alloc_mr = siw_alloc_mr,
+	.alloc_pd = siw_alloc_pd,
+	.alloc_ucontext = siw_alloc_ucontext,
+	.create_cq = siw_create_cq,
+	.create_qp = siw_create_qp,
+	.create_srq = siw_create_srq,
+	.dealloc_driver = siw_device_cleanup,
+	.dealloc_pd = siw_dealloc_pd,
+	.dealloc_ucontext = siw_dealloc_ucontext,
+	.dereg_mr = siw_dereg_mr,
+	.destroy_cq = siw_destroy_cq,
+	.destroy_qp = siw_destroy_qp,
+	.destroy_srq = siw_destroy_srq,
+	.drain_rq = siw_verbs_rq_flush,
+	.drain_sq = siw_verbs_sq_flush,
+	.get_dma_mr = siw_get_dma_mr,
+	.get_port_immutable = siw_get_port_immutable,
+	.iw_accept = siw_accept,
+	.iw_add_ref = siw_qp_get_ref,
+	.iw_connect = siw_connect,
+	.iw_create_listen = siw_create_listen,
+	.iw_destroy_listen = siw_destroy_listen,
+	.iw_get_qp = siw_get_base_qp,
+	.iw_reject = siw_reject,
+	.iw_rem_ref = siw_qp_put_ref,
+	.map_mr_sg = siw_map_mr_sg,
+	.mmap = siw_mmap,
+	.modify_qp = siw_verbs_modify_qp,
+	.modify_srq = siw_modify_srq,
+	.poll_cq = siw_poll_cq,
+	.post_recv = siw_post_receive,
+	.post_send = siw_post_send,
+	.post_srq_recv = siw_post_srq_recv,
+	.query_device = siw_query_device,
+	.query_gid = siw_query_gid,
+	.query_pkey = siw_query_pkey,
+	.query_port = siw_query_port,
+	.query_qp = siw_query_qp,
+	.query_srq = siw_query_srq,
+	.req_notify_cq = siw_req_notify_cq,
+	.reg_user_mr = siw_reg_user_mr,
+
+	INIT_RDMA_OBJ_SIZE(ib_cq, siw_cq, base_cq),
+	INIT_RDMA_OBJ_SIZE(ib_pd, siw_pd, base_pd),
+	INIT_RDMA_OBJ_SIZE(ib_srq, siw_srq, base_srq),
+	INIT_RDMA_OBJ_SIZE(ib_ucontext, siw_ucontext, base_ucontext),
+};
+
+static struct siw_device *siw_device_create(struct net_device *netdev)
+{
+	struct siw_device *sdev = NULL;
+	struct ib_device *base_dev;
+	struct device *parent = netdev->dev.parent;
+	int rv;
+
+	if (!parent) {
+		/*
+		 * The loopback device has no parent device,
+		 * so it appears as a top-level device. To support
+		 * loopback device connectivity, take this device
+		 * as the parent device. Skip all other devices
+		 * w/o parent device.
+		 */
+		if (netdev->type != ARPHRD_LOOPBACK) {
+			pr_warn("siw: device %s error: no parent device\n",
+				netdev->name);
+			return NULL;
+		}
+		parent = &netdev->dev;
+	}
+	sdev = ib_alloc_device(siw_device, base_dev);
+	if (!sdev)
+		return NULL;
+
+	base_dev = &sdev->base_dev;
+
+	sdev->netdev = netdev;
+
+	if (netdev->type != ARPHRD_LOOPBACK) {
+		memcpy(&base_dev->node_guid, netdev->dev_addr, 6);
+	} else {
+		/*
+		 * The loopback device does not have a HW address,
+		 * but connection mangagement lib expects gid != 0
+		 */
+		size_t gidlen = min_t(size_t, strlen(base_dev->name), 6);
+
+		memcpy(&base_dev->node_guid, base_dev->name, gidlen);
+	}
+	base_dev->uverbs_cmd_mask =
+		(1ull << IB_USER_VERBS_CMD_QUERY_DEVICE) |
+		(1ull << IB_USER_VERBS_CMD_QUERY_PORT) |
+		(1ull << IB_USER_VERBS_CMD_GET_CONTEXT) |
+		(1ull << IB_USER_VERBS_CMD_ALLOC_PD) |
+		(1ull << IB_USER_VERBS_CMD_DEALLOC_PD) |
+		(1ull << IB_USER_VERBS_CMD_REG_MR) |
+		(1ull << IB_USER_VERBS_CMD_DEREG_MR) |
+		(1ull << IB_USER_VERBS_CMD_CREATE_COMP_CHANNEL) |
+		(1ull << IB_USER_VERBS_CMD_CREATE_CQ) |
+		(1ull << IB_USER_VERBS_CMD_POLL_CQ) |
+		(1ull << IB_USER_VERBS_CMD_REQ_NOTIFY_CQ) |
+		(1ull << IB_USER_VERBS_CMD_DESTROY_CQ) |
+		(1ull << IB_USER_VERBS_CMD_CREATE_QP) |
+		(1ull << IB_USER_VERBS_CMD_QUERY_QP) |
+		(1ull << IB_USER_VERBS_CMD_MODIFY_QP) |
+		(1ull << IB_USER_VERBS_CMD_DESTROY_QP) |
+		(1ull << IB_USER_VERBS_CMD_POST_SEND) |
+		(1ull << IB_USER_VERBS_CMD_POST_RECV) |
+		(1ull << IB_USER_VERBS_CMD_CREATE_SRQ) |
+		(1ull << IB_USER_VERBS_CMD_POST_SRQ_RECV) |
+		(1ull << IB_USER_VERBS_CMD_MODIFY_SRQ) |
+		(1ull << IB_USER_VERBS_CMD_QUERY_SRQ) |
+		(1ull << IB_USER_VERBS_CMD_DESTROY_SRQ);
+
+	base_dev->node_type = RDMA_NODE_RNIC;
+	memcpy(base_dev->node_desc, SIW_NODE_DESC_COMMON,
+	       sizeof(SIW_NODE_DESC_COMMON));
+
+	/*
+	 * Current model (one-to-one device association):
+	 * One Softiwarp device per net_device or, equivalently,
+	 * per physical port.
+	 */
+	base_dev->phys_port_cnt = 1;
+	base_dev->dev.parent = parent;
+	base_dev->dev.dma_ops = &dma_virt_ops;
+	base_dev->num_comp_vectors = num_possible_cpus();
+
+	ib_set_device_ops(base_dev, &siw_device_ops);
+	rv = ib_device_set_netdev(base_dev, netdev, 1);
+	if (rv)
+		goto error;
+
+	memcpy(base_dev->iw_ifname, netdev->name,
+	       sizeof(base_dev->iw_ifname));
+
+	/* Disable TCP port mapping */
+	base_dev->iw_driver_flags = IW_F_NO_PORT_MAP,
+
+	sdev->attrs.max_qp = SIW_MAX_QP;
+	sdev->attrs.max_qp_wr = SIW_MAX_QP_WR;
+	sdev->attrs.max_ord = SIW_MAX_ORD_QP;
+	sdev->attrs.max_ird = SIW_MAX_IRD_QP;
+	sdev->attrs.max_sge = SIW_MAX_SGE;
+	sdev->attrs.max_sge_rd = SIW_MAX_SGE_RD;
+	sdev->attrs.max_cq = SIW_MAX_CQ;
+	sdev->attrs.max_cqe = SIW_MAX_CQE;
+	sdev->attrs.max_mr = SIW_MAX_MR;
+	sdev->attrs.max_pd = SIW_MAX_PD;
+	sdev->attrs.max_mw = SIW_MAX_MW;
+	sdev->attrs.max_fmr = SIW_MAX_FMR;
+	sdev->attrs.max_srq = SIW_MAX_SRQ;
+	sdev->attrs.max_srq_wr = SIW_MAX_SRQ_WR;
+	sdev->attrs.max_srq_sge = SIW_MAX_SGE;
+
+	xa_init_flags(&sdev->qp_xa, XA_FLAGS_ALLOC1);
+	xa_init_flags(&sdev->mem_xa, XA_FLAGS_ALLOC1);
+
+	INIT_LIST_HEAD(&sdev->cep_list);
+	INIT_LIST_HEAD(&sdev->qp_list);
+
+	atomic_set(&sdev->num_ctx, 0);
+	atomic_set(&sdev->num_srq, 0);
+	atomic_set(&sdev->num_qp, 0);
+	atomic_set(&sdev->num_cq, 0);
+	atomic_set(&sdev->num_mr, 0);
+	atomic_set(&sdev->num_pd, 0);
+
+	sdev->numa_node = dev_to_node(parent);
+	spin_lock_init(&sdev->lock);
+
+	return sdev;
+error:
+	ib_dealloc_device(base_dev);
+
+	return NULL;
+}
+
+/*
+ * Network link becomes unavailable. Mark all
+ * affected QP's accordingly.
+ */
+static void siw_netdev_down(struct work_struct *work)
+{
+	struct siw_device *sdev =
+		container_of(work, struct siw_device, netdev_down);
+
+	struct siw_qp_attrs qp_attrs;
+	struct list_head *pos, *tmp;
+
+	memset(&qp_attrs, 0, sizeof(qp_attrs));
+	qp_attrs.state = SIW_QP_STATE_ERROR;
+
+	list_for_each_safe(pos, tmp, &sdev->qp_list) {
+		struct siw_qp *qp = list_entry(pos, struct siw_qp, devq);
+
+		down_write(&qp->state_lock);
+		WARN_ON(siw_qp_modify(qp, &qp_attrs, SIW_QP_ATTR_STATE));
+		up_write(&qp->state_lock);
+	}
+	ib_device_put(&sdev->base_dev);
+}
+
+static void siw_device_goes_down(struct siw_device *sdev)
+{
+	if (ib_device_try_get(&sdev->base_dev)) {
+		INIT_WORK(&sdev->netdev_down, siw_netdev_down);
+		schedule_work(&sdev->netdev_down);
+	}
+}
+
+static int siw_netdev_event(struct notifier_block *nb, unsigned long event,
+			    void *arg)
+{
+	struct net_device *netdev = netdev_notifier_info_to_dev(arg);
+	struct ib_device *base_dev;
+	struct siw_device *sdev;
+
+	dev_dbg(&netdev->dev, "siw: event %lu\n", event);
+
+	if (dev_net(netdev) != &init_net)
+		return NOTIFY_OK;
+
+	base_dev = ib_device_get_by_netdev(netdev, RDMA_DRIVER_SIW);
+	if (!base_dev)
+		return NOTIFY_OK;
+
+	sdev = to_siw_dev(base_dev);
+
+	switch (event) {
+	case NETDEV_UP:
+		sdev->state = IB_PORT_ACTIVE;
+		siw_port_event(sdev, 1, IB_EVENT_PORT_ACTIVE);
+		break;
+
+	case NETDEV_GOING_DOWN:
+		siw_device_goes_down(sdev);
+		break;
+
+	case NETDEV_DOWN:
+		sdev->state = IB_PORT_DOWN;
+		siw_port_event(sdev, 1, IB_EVENT_PORT_ERR);
+		break;
+
+	case NETDEV_REGISTER:
+		/*
+		 * Device registration now handled only by
+		 * rdma netlink commands. So it shall be impossible
+		 * to end up here with a valid siw device.
+		 */
+		siw_dbg(base_dev, "unexpected NETDEV_REGISTER event\n");
+		break;
+
+	case NETDEV_UNREGISTER:
+		ib_unregister_device_queued(&sdev->base_dev);
+		break;
+
+	case NETDEV_CHANGEADDR:
+		siw_port_event(sdev, 1, IB_EVENT_LID_CHANGE);
+		break;
+	/*
+	 * Todo: Below netdev events are currently not handled.
+	 */
+	case NETDEV_CHANGEMTU:
+	case NETDEV_CHANGE:
+		break;
+
+	default:
+		break;
+	}
+	ib_device_put(&sdev->base_dev);
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block siw_netdev_nb = {
+	.notifier_call = siw_netdev_event,
+};
+
+static int siw_newlink(const char *basedev_name, struct net_device *netdev)
+{
+	struct ib_device *base_dev;
+	struct siw_device *sdev = NULL;
+	int rv = -ENOMEM;
+
+	if (!siw_dev_qualified(netdev))
+		return -EINVAL;
+
+	base_dev = ib_device_get_by_netdev(netdev, RDMA_DRIVER_SIW);
+	if (base_dev) {
+		ib_device_put(base_dev);
+		return -EEXIST;
+	}
+	sdev = siw_device_create(netdev);
+	if (sdev) {
+		dev_dbg(&netdev->dev, "siw: new device\n");
+
+		if (netif_running(netdev) && netif_carrier_ok(netdev))
+			sdev->state = IB_PORT_ACTIVE;
+		else
+			sdev->state = IB_PORT_DOWN;
+
+		rv = siw_device_register(sdev, basedev_name);
+		if (rv)
+			ib_dealloc_device(&sdev->base_dev);
+	}
+	return rv;
+}
+
+static struct rdma_link_ops siw_link_ops = {
+	.type = "siw",
+	.newlink = siw_newlink,
+};
+
+/*
+ * siw_init_module - Initialize Softiwarp module and register with netdev
+ *                   subsystem.
+ */
+static __init int siw_init_module(void)
+{
+	int rv;
+	int nr_cpu;
+
+	if (SENDPAGE_THRESH < SIW_MAX_INLINE) {
+		pr_info("siw: sendpage threshold too small: %u\n",
+			(int)SENDPAGE_THRESH);
+		rv = -EINVAL;
+		goto out_error;
+	}
+	rv = siw_init_cpulist();
+	if (rv)
+		goto out_error;
+
+	rv = siw_cm_init();
+	if (rv)
+		goto out_error;
+
+	if (!siw_create_tx_threads()) {
+		pr_info("siw: Could not start any TX thread\n");
+		goto out_error;
+	}
+	/*
+	 * Locate CRC32 algorithm. If unsuccessful, fail
+	 * loading siw only, if CRC is required.
+	 */
+	siw_crypto_shash = crypto_alloc_shash("crc32c", 0, 0);
+	if (IS_ERR(siw_crypto_shash)) {
+		pr_info("siw: Loading CRC32c failed: %ld\n",
+			PTR_ERR(siw_crypto_shash));
+		siw_crypto_shash = NULL;
+		if (mpa_crc_required) {
+			rv = -EOPNOTSUPP;
+			goto out_error;
+		}
+	}
+	rv = register_netdevice_notifier(&siw_netdev_nb);
+	if (rv)
+		goto out_error;
+
+	rdma_link_register(&siw_link_ops);
+
+	pr_info("SoftiWARP attached\n");
+	return 0;
+
+out_error:
+	for (nr_cpu = 0; nr_cpu < nr_cpu_ids; nr_cpu++) {
+		if (siw_tx_thread[nr_cpu]) {
+			siw_stop_tx_thread(nr_cpu);
+			siw_tx_thread[nr_cpu] = NULL;
+		}
+	}
+	if (siw_crypto_shash)
+		crypto_free_shash(siw_crypto_shash);
+
+	pr_info("SoftIWARP attach failed. Error: %d\n", rv);
+
+	siw_cm_exit();
+	siw_destroy_cpulist();
+
+	return rv;
+}
+
+static void __exit siw_exit_module(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu) {
+		if (siw_tx_thread[cpu]) {
+			siw_stop_tx_thread(cpu);
+			siw_tx_thread[cpu] = NULL;
+		}
+	}
+	unregister_netdevice_notifier(&siw_netdev_nb);
+	rdma_link_unregister(&siw_link_ops);
+	ib_unregister_driver(RDMA_DRIVER_SIW);
+
+	siw_cm_exit();
+
+	siw_destroy_cpulist();
+
+	if (siw_crypto_shash)
+		crypto_free_shash(siw_crypto_shash);
+
+	pr_info("SoftiWARP detached\n");
+}
+
+module_init(siw_init_module);
+module_exit(siw_exit_module);
+
+MODULE_ALIAS_RDMA_LINK("siw");