RDMA/cma: Export rdma cm interface to userspace

Export the rdma cm interfaces to userspace via a misc device.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 874 insertions, 0 deletions

diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c
new file mode 100644
index 000000000000..81a5cdc5733a
--- /dev/null
+++ b/drivers/infiniband/core/ucma.c
@@ -0,0 +1,874 @@
+/*
+ * Copyright (c) 2005-2006 Intel Corporation.  All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *	copyright notice, this list of conditions and the following
+ *	disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *	copyright notice, this list of conditions and the following
+ *	disclaimer in the documentation and/or other materials
+ *	provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <linux/completion.h>
+#include <linux/mutex.h>
+#include <linux/poll.h>
+#include <linux/idr.h>
+#include <linux/in.h>
+#include <linux/in6.h>
+#include <linux/miscdevice.h>
+
+#include <rdma/rdma_user_cm.h>
+#include <rdma/ib_marshall.h>
+#include <rdma/rdma_cm.h>
+
+MODULE_AUTHOR("Sean Hefty");
+MODULE_DESCRIPTION("RDMA Userspace Connection Manager Access");
+MODULE_LICENSE("Dual BSD/GPL");
+
+enum {
+	UCMA_MAX_BACKLOG	= 128
+};
+
+struct ucma_file {
+	struct mutex		mut;
+	struct file		*filp;
+	struct list_head	ctx_list;
+	struct list_head	event_list;
+	wait_queue_head_t	poll_wait;
+};
+
+struct ucma_context {
+	int			id;
+	struct completion	comp;
+	atomic_t		ref;
+	int			events_reported;
+	int			backlog;
+
+	struct ucma_file	*file;
+	struct rdma_cm_id	*cm_id;
+	u64			uid;
+
+	struct list_head	list;
+};
+
+struct ucma_event {
+	struct ucma_context	*ctx;
+	struct list_head	list;
+	struct rdma_cm_id	*cm_id;
+	struct rdma_ucm_event_resp resp;
+};
+
+static DEFINE_MUTEX(mut);
+static DEFINE_IDR(ctx_idr);
+
+static inline struct ucma_context *_ucma_find_context(int id,
+						      struct ucma_file *file)
+{
+	struct ucma_context *ctx;
+
+	ctx = idr_find(&ctx_idr, id);
+	if (!ctx)
+		ctx = ERR_PTR(-ENOENT);
+	else if (ctx->file != file)
+		ctx = ERR_PTR(-EINVAL);
+	return ctx;
+}
+
+static struct ucma_context *ucma_get_ctx(struct ucma_file *file, int id)
+{
+	struct ucma_context *ctx;
+
+	mutex_lock(&mut);
+	ctx = _ucma_find_context(id, file);
+	if (!IS_ERR(ctx))
+		atomic_inc(&ctx->ref);
+	mutex_unlock(&mut);
+	return ctx;
+}
+
+static void ucma_put_ctx(struct ucma_context *ctx)
+{
+	if (atomic_dec_and_test(&ctx->ref))
+		complete(&ctx->comp);
+}
+
+static struct ucma_context *ucma_alloc_ctx(struct ucma_file *file)
+{
+	struct ucma_context *ctx;
+	int ret;
+
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return NULL;
+
+	atomic_set(&ctx->ref, 1);
+	init_completion(&ctx->comp);
+	ctx->file = file;
+
+	do {
+		ret = idr_pre_get(&ctx_idr, GFP_KERNEL);
+		if (!ret)
+			goto error;
+
+		mutex_lock(&mut);
+		ret = idr_get_new(&ctx_idr, ctx, &ctx->id);
+		mutex_unlock(&mut);
+	} while (ret == -EAGAIN);
+
+	if (ret)
+		goto error;
+
+	list_add_tail(&ctx->list, &file->ctx_list);
+	return ctx;
+
+error:
+	kfree(ctx);
+	return NULL;
+}
+
+static void ucma_copy_conn_event(struct rdma_ucm_conn_param *dst,
+				 struct rdma_conn_param *src)
+{
+	if (src->private_data_len)
+		memcpy(dst->private_data, src->private_data,
+		       src->private_data_len);
+	dst->private_data_len = src->private_data_len;
+	dst->responder_resources =src->responder_resources;
+	dst->initiator_depth = src->initiator_depth;
+	dst->flow_control = src->flow_control;
+	dst->retry_count = src->retry_count;
+	dst->rnr_retry_count = src->rnr_retry_count;
+	dst->srq = src->srq;
+	dst->qp_num = src->qp_num;
+}
+
+static void ucma_copy_ud_event(struct rdma_ucm_ud_param *dst,
+			       struct rdma_ud_param *src)
+{
+	if (src->private_data_len)
+		memcpy(dst->private_data, src->private_data,
+		       src->private_data_len);
+	dst->private_data_len = src->private_data_len;
+	ib_copy_ah_attr_to_user(&dst->ah_attr, &src->ah_attr);
+	dst->qp_num = src->qp_num;
+	dst->qkey = src->qkey;
+}
+
+static void ucma_set_event_context(struct ucma_context *ctx,
+				   struct rdma_cm_event *event,
+				   struct ucma_event *uevent)
+{
+	uevent->ctx = ctx;
+	uevent->resp.uid = ctx->uid;
+	uevent->resp.id = ctx->id;
+}
+
+static int ucma_event_handler(struct rdma_cm_id *cm_id,
+			      struct rdma_cm_event *event)
+{
+	struct ucma_event *uevent;
+	struct ucma_context *ctx = cm_id->context;
+	int ret = 0;
+
+	uevent = kzalloc(sizeof(*uevent), GFP_KERNEL);
+	if (!uevent)
+		return event->event == RDMA_CM_EVENT_CONNECT_REQUEST;
+
+	uevent->cm_id = cm_id;
+	ucma_set_event_context(ctx, event, uevent);
+	uevent->resp.event = event->event;
+	uevent->resp.status = event->status;
+	if (cm_id->ps == RDMA_PS_UDP)
+		ucma_copy_ud_event(&uevent->resp.param.ud, &event->param.ud);
+	else
+		ucma_copy_conn_event(&uevent->resp.param.conn,
+				     &event->param.conn);
+
+	mutex_lock(&ctx->file->mut);
+	if (event->event == RDMA_CM_EVENT_CONNECT_REQUEST) {
+		if (!ctx->backlog) {
+			ret = -EDQUOT;
+			goto out;
+		}
+		ctx->backlog--;
+	}
+	list_add_tail(&uevent->list, &ctx->file->event_list);
+	wake_up_interruptible(&ctx->file->poll_wait);
+out:
+	mutex_unlock(&ctx->file->mut);
+	return ret;
+}
+
+static ssize_t ucma_get_event(struct ucma_file *file, const char __user *inbuf,
+			      int in_len, int out_len)
+{
+	struct ucma_context *ctx;
+	struct rdma_ucm_get_event cmd;
+	struct ucma_event *uevent;
+	int ret = 0;
+	DEFINE_WAIT(wait);
+
+	if (out_len < sizeof uevent->resp)
+		return -ENOSPC;
+
+	if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
+		return -EFAULT;
+
+	mutex_lock(&file->mut);
+	while (list_empty(&file->event_list)) {
+		if (file->filp->f_flags & O_NONBLOCK) {
+			ret = -EAGAIN;
+			break;
+		}
+
+		if (signal_pending(current)) {
+			ret = -ERESTARTSYS;
+			break;
+		}
+
+		prepare_to_wait(&file->poll_wait, &wait, TASK_INTERRUPTIBLE);
+		mutex_unlock(&file->mut);
+		schedule();
+		mutex_lock(&file->mut);
+		finish_wait(&file->poll_wait, &wait);
+	}
+
+	if (ret)
+		goto done;
+
+	uevent = list_entry(file->event_list.next, struct ucma_event, list);
+
+	if (uevent->resp.event == RDMA_CM_EVENT_CONNECT_REQUEST) {
+		ctx = ucma_alloc_ctx(file);
+		if (!ctx) {
+			ret = -ENOMEM;
+			goto done;
+		}
+		uevent->ctx->backlog++;
+		ctx->cm_id = uevent->cm_id;
+		ctx->cm_id->context = ctx;
+		uevent->resp.id = ctx->id;
+	}
+
+	if (copy_to_user((void __user *)(unsigned long)cmd.response,
+			 &uevent->resp, sizeof uevent->resp)) {
+		ret = -EFAULT;
+		goto done;
+	}
+
+	list_del(&uevent->list);
+	uevent->ctx->events_reported++;
+	kfree(uevent);
+done:
+	mutex_unlock(&file->mut);
+	return ret;
+}
+
+static ssize_t ucma_create_id(struct ucma_file *file,
+				const char __user *inbuf,
+				int in_len, int out_len)
+{
+	struct rdma_ucm_create_id cmd;
+	struct rdma_ucm_create_id_resp resp;
+	struct ucma_context *ctx;
+	int ret;
+
+	if (out_len < sizeof(resp))
+		return -ENOSPC;
+
+	if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
+		return -EFAULT;
+
+	mutex_lock(&file->mut);
+	ctx = ucma_alloc_ctx(file);
+	mutex_unlock(&file->mut);
+	if (!ctx)
+		return -ENOMEM;
+
+	ctx->uid = cmd.uid;
+	ctx->cm_id = rdma_create_id(ucma_event_handler, ctx, cmd.ps);
+	if (IS_ERR(ctx->cm_id)) {
+		ret = PTR_ERR(ctx->cm_id);
+		goto err1;
+	}
+
+	resp.id = ctx->id;
+	if (copy_to_user((void __user *)(unsigned long)cmd.response,
+			 &resp, sizeof(resp))) {
+		ret = -EFAULT;
+		goto err2;
+	}
+	return 0;
+
+err2:
+	rdma_destroy_id(ctx->cm_id);
+err1:
+	mutex_lock(&mut);
+	idr_remove(&ctx_idr, ctx->id);
+	mutex_unlock(&mut);
+	kfree(ctx);
+	return ret;
+}
+
+static void ucma_cleanup_events(struct ucma_context *ctx)
+{
+	struct ucma_event *uevent, *tmp;
+
+	list_for_each_entry_safe(uevent, tmp, &ctx->file->event_list, list) {
+		if (uevent->ctx != ctx)
+			continue;
+
+		list_del(&uevent->list);
+
+		/* clear incoming connections. */
+		if (uevent->resp.event == RDMA_CM_EVENT_CONNECT_REQUEST)
+			rdma_destroy_id(uevent->cm_id);
+
+		kfree(uevent);
+	}
+}
+
+static int ucma_free_ctx(struct ucma_context *ctx)
+{
+	int events_reported;
+
+	/* No new events will be generated after destroying the id. */
+	rdma_destroy_id(ctx->cm_id);
+
+	/* Cleanup events not yet reported to the user. */
+	mutex_lock(&ctx->file->mut);
+	ucma_cleanup_events(ctx);
+	list_del(&ctx->list);
+	mutex_unlock(&ctx->file->mut);
+
+	events_reported = ctx->events_reported;
+	kfree(ctx);
+	return events_reported;
+}
+
+static ssize_t ucma_destroy_id(struct ucma_file *file, const char __user *inbuf,
+			       int in_len, int out_len)
+{
+	struct rdma_ucm_destroy_id cmd;
+	struct rdma_ucm_destroy_id_resp resp;
+	struct ucma_context *ctx;
+	int ret = 0;
+
+	if (out_len < sizeof(resp))
+		return -ENOSPC;
+
+	if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
+		return -EFAULT;
+
+	mutex_lock(&mut);
+	ctx = _ucma_find_context(cmd.id, file);
+	if (!IS_ERR(ctx))
+		idr_remove(&ctx_idr, ctx->id);
+	mutex_unlock(&mut);
+
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
+	ucma_put_ctx(ctx);
+	wait_for_completion(&ctx->comp);
+	resp.events_reported = ucma_free_ctx(ctx);
+
+	if (copy_to_user((void __user *)(unsigned long)cmd.response,
+			 &resp, sizeof(resp)))
+		ret = -EFAULT;
+
+	return ret;
+}
+
+static ssize_t ucma_bind_addr(struct ucma_file *file, const char __user *inbuf,
+			      int in_len, int out_len)
+{
+	struct rdma_ucm_bind_addr cmd;
+	struct ucma_context *ctx;
+	int ret;
+
+	if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
+		return -EFAULT;
+
+	ctx = ucma_get_ctx(file, cmd.id);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
+	ret = rdma_bind_addr(ctx->cm_id, (struct sockaddr *) &cmd.addr);
+	ucma_put_ctx(ctx);
+	return ret;
+}
+
+static ssize_t ucma_resolve_addr(struct ucma_file *file,
+				 const char __user *inbuf,
+				 int in_len, int out_len)
+{
+	struct rdma_ucm_resolve_addr cmd;
+	struct ucma_context *ctx;
+	int ret;
+
+	if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
+		return -EFAULT;
+
+	ctx = ucma_get_ctx(file, cmd.id);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
+	ret = rdma_resolve_addr(ctx->cm_id, (struct sockaddr *) &cmd.src_addr,
+				(struct sockaddr *) &cmd.dst_addr,
+				cmd.timeout_ms);
+	ucma_put_ctx(ctx);
+	return ret;
+}
+
+static ssize_t ucma_resolve_route(struct ucma_file *file,
+				  const char __user *inbuf,
+				  int in_len, int out_len)
+{
+	struct rdma_ucm_resolve_route cmd;
+	struct ucma_context *ctx;
+	int ret;
+
+	if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
+		return -EFAULT;
+
+	ctx = ucma_get_ctx(file, cmd.id);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
+	ret = rdma_resolve_route(ctx->cm_id, cmd.timeout_ms);
+	ucma_put_ctx(ctx);
+	return ret;
+}
+
+static void ucma_copy_ib_route(struct rdma_ucm_query_route_resp *resp,
+			       struct rdma_route *route)
+{
+	struct rdma_dev_addr *dev_addr;
+
+	resp->num_paths = route->num_paths;
+	switch (route->num_paths) {
+	case 0:
+		dev_addr = &route->addr.dev_addr;
+		ib_addr_get_dgid(dev_addr,
+				 (union ib_gid *) &resp->ib_route[0].dgid);
+		ib_addr_get_sgid(dev_addr,
+				 (union ib_gid *) &resp->ib_route[0].sgid);
+		resp->ib_route[0].pkey = cpu_to_be16(ib_addr_get_pkey(dev_addr));
+		break;
+	case 2:
+		ib_copy_path_rec_to_user(&resp->ib_route[1],
+					 &route->path_rec[1]);
+		/* fall through */
+	case 1:
+		ib_copy_path_rec_to_user(&resp->ib_route[0],
+					 &route->path_rec[0]);
+		break;
+	default:
+		break;
+	}
+}
+
+static ssize_t ucma_query_route(struct ucma_file *file,
+				const char __user *inbuf,
+				int in_len, int out_len)
+{
+	struct rdma_ucm_query_route cmd;
+	struct rdma_ucm_query_route_resp resp;
+	struct ucma_context *ctx;
+	struct sockaddr *addr;
+	int ret = 0;
+
+	if (out_len < sizeof(resp))
+		return -ENOSPC;
+
+	if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
+		return -EFAULT;
+
+	ctx = ucma_get_ctx(file, cmd.id);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
+	memset(&resp, 0, sizeof resp);
+	addr = &ctx->cm_id->route.addr.src_addr;
+	memcpy(&resp.src_addr, addr, addr->sa_family == AF_INET ?
+				     sizeof(struct sockaddr_in) :
+				     sizeof(struct sockaddr_in6));
+	addr = &ctx->cm_id->route.addr.dst_addr;
+	memcpy(&resp.dst_addr, addr, addr->sa_family == AF_INET ?
+				     sizeof(struct sockaddr_in) :
+				     sizeof(struct sockaddr_in6));
+	if (!ctx->cm_id->device)
+		goto out;
+
+	resp.node_guid = ctx->cm_id->device->node_guid;
+	resp.port_num = ctx->cm_id->port_num;
+	switch (rdma_node_get_transport(ctx->cm_id->device->node_type)) {
+	case RDMA_TRANSPORT_IB:
+		ucma_copy_ib_route(&resp, &ctx->cm_id->route);
+		break;
+	default:
+		break;
+	}
+
+out:
+	if (copy_to_user((void __user *)(unsigned long)cmd.response,
+			 &resp, sizeof(resp)))
+		ret = -EFAULT;
+
+	ucma_put_ctx(ctx);
+	return ret;
+}
+
+static void ucma_copy_conn_param(struct rdma_conn_param *dst,
+				 struct rdma_ucm_conn_param *src)
+{
+	dst->private_data = src->private_data;
+	dst->private_data_len = src->private_data_len;
+	dst->responder_resources =src->responder_resources;
+	dst->initiator_depth = src->initiator_depth;
+	dst->flow_control = src->flow_control;
+	dst->retry_count = src->retry_count;
+	dst->rnr_retry_count = src->rnr_retry_count;
+	dst->srq = src->srq;
+	dst->qp_num = src->qp_num;
+}
+
+static ssize_t ucma_connect(struct ucma_file *file, const char __user *inbuf,
+			    int in_len, int out_len)
+{
+	struct rdma_ucm_connect cmd;
+	struct rdma_conn_param conn_param;
+	struct ucma_context *ctx;
+	int ret;
+
+	if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
+		return -EFAULT;
+
+	if (!cmd.conn_param.valid)
+		return -EINVAL;
+
+	ctx = ucma_get_ctx(file, cmd.id);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
+	ucma_copy_conn_param(&conn_param, &cmd.conn_param);
+	ret = rdma_connect(ctx->cm_id, &conn_param);
+	ucma_put_ctx(ctx);
+	return ret;
+}
+
+static ssize_t ucma_listen(struct ucma_file *file, const char __user *inbuf,
+			   int in_len, int out_len)
+{
+	struct rdma_ucm_listen cmd;
+	struct ucma_context *ctx;
+	int ret;
+
+	if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
+		return -EFAULT;
+
+	ctx = ucma_get_ctx(file, cmd.id);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
+	ctx->backlog = cmd.backlog > 0 && cmd.backlog < UCMA_MAX_BACKLOG ?
+		       cmd.backlog : UCMA_MAX_BACKLOG;
+	ret = rdma_listen(ctx->cm_id, ctx->backlog);
+	ucma_put_ctx(ctx);
+	return ret;
+}
+
+static ssize_t ucma_accept(struct ucma_file *file, const char __user *inbuf,
+			   int in_len, int out_len)
+{
+	struct rdma_ucm_accept cmd;
+	struct rdma_conn_param conn_param;
+	struct ucma_context *ctx;
+	int ret;
+
+	if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
+		return -EFAULT;
+
+	ctx = ucma_get_ctx(file, cmd.id);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
+	if (cmd.conn_param.valid) {
+		ctx->uid = cmd.uid;
+		ucma_copy_conn_param(&conn_param, &cmd.conn_param);
+		ret = rdma_accept(ctx->cm_id, &conn_param);
+	} else
+		ret = rdma_accept(ctx->cm_id, NULL);
+
+	ucma_put_ctx(ctx);
+	return ret;
+}
+
+static ssize_t ucma_reject(struct ucma_file *file, const char __user *inbuf,
+			   int in_len, int out_len)
+{
+	struct rdma_ucm_reject cmd;
+	struct ucma_context *ctx;
+	int ret;
+
+	if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
+		return -EFAULT;
+
+	ctx = ucma_get_ctx(file, cmd.id);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
+	ret = rdma_reject(ctx->cm_id, cmd.private_data, cmd.private_data_len);
+	ucma_put_ctx(ctx);
+	return ret;
+}
+
+static ssize_t ucma_disconnect(struct ucma_file *file, const char __user *inbuf,
+			       int in_len, int out_len)
+{
+	struct rdma_ucm_disconnect cmd;
+	struct ucma_context *ctx;
+	int ret;
+
+	if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
+		return -EFAULT;
+
+	ctx = ucma_get_ctx(file, cmd.id);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
+	ret = rdma_disconnect(ctx->cm_id);
+	ucma_put_ctx(ctx);
+	return ret;
+}
+
+static ssize_t ucma_init_qp_attr(struct ucma_file *file,
+				 const char __user *inbuf,
+				 int in_len, int out_len)
+{
+	struct rdma_ucm_init_qp_attr cmd;
+	struct ib_uverbs_qp_attr resp;
+	struct ucma_context *ctx;
+	struct ib_qp_attr qp_attr;
+	int ret;
+
+	if (out_len < sizeof(resp))
+		return -ENOSPC;
+
+	if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
+		return -EFAULT;
+
+	ctx = ucma_get_ctx(file, cmd.id);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
+	resp.qp_attr_mask = 0;
+	memset(&qp_attr, 0, sizeof qp_attr);
+	qp_attr.qp_state = cmd.qp_state;
+	ret = rdma_init_qp_attr(ctx->cm_id, &qp_attr, &resp.qp_attr_mask);
+	if (ret)
+		goto out;
+
+	ib_copy_qp_attr_to_user(&resp, &qp_attr);
+	if (copy_to_user((void __user *)(unsigned long)cmd.response,
+			 &resp, sizeof(resp)))
+		ret = -EFAULT;
+
+out:
+	ucma_put_ctx(ctx);
+	return ret;
+}
+
+static ssize_t ucma_notify(struct ucma_file *file, const char __user *inbuf,
+			   int in_len, int out_len)
+{
+	struct rdma_ucm_notify cmd;
+	struct ucma_context *ctx;
+	int ret;
+
+	if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
+		return -EFAULT;
+
+	ctx = ucma_get_ctx(file, cmd.id);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
+	ret = rdma_notify(ctx->cm_id, (enum ib_event_type) cmd.event);
+	ucma_put_ctx(ctx);
+	return ret;
+}
+
+static ssize_t (*ucma_cmd_table[])(struct ucma_file *file,
+				   const char __user *inbuf,
+				   int in_len, int out_len) = {
+	[RDMA_USER_CM_CMD_CREATE_ID]	= ucma_create_id,
+	[RDMA_USER_CM_CMD_DESTROY_ID]	= ucma_destroy_id,
+	[RDMA_USER_CM_CMD_BIND_ADDR]	= ucma_bind_addr,
+	[RDMA_USER_CM_CMD_RESOLVE_ADDR]	= ucma_resolve_addr,
+	[RDMA_USER_CM_CMD_RESOLVE_ROUTE]= ucma_resolve_route,
+	[RDMA_USER_CM_CMD_QUERY_ROUTE]	= ucma_query_route,
+	[RDMA_USER_CM_CMD_CONNECT]	= ucma_connect,
+	[RDMA_USER_CM_CMD_LISTEN]	= ucma_listen,
+	[RDMA_USER_CM_CMD_ACCEPT]	= ucma_accept,
+	[RDMA_USER_CM_CMD_REJECT]	= ucma_reject,
+	[RDMA_USER_CM_CMD_DISCONNECT]	= ucma_disconnect,
+	[RDMA_USER_CM_CMD_INIT_QP_ATTR]	= ucma_init_qp_attr,
+	[RDMA_USER_CM_CMD_GET_EVENT]	= ucma_get_event,
+	[RDMA_USER_CM_CMD_GET_OPTION]	= NULL,
+	[RDMA_USER_CM_CMD_SET_OPTION]	= NULL,
+	[RDMA_USER_CM_CMD_NOTIFY]	= ucma_notify,
+};
+
+static ssize_t ucma_write(struct file *filp, const char __user *buf,
+			  size_t len, loff_t *pos)
+{
+	struct ucma_file *file = filp->private_data;
+	struct rdma_ucm_cmd_hdr hdr;
+	ssize_t ret;
+
+	if (len < sizeof(hdr))
+		return -EINVAL;
+
+	if (copy_from_user(&hdr, buf, sizeof(hdr)))
+		return -EFAULT;
+
+	if (hdr.cmd < 0 || hdr.cmd >= ARRAY_SIZE(ucma_cmd_table))
+		return -EINVAL;
+
+	if (hdr.in + sizeof(hdr) > len)
+		return -EINVAL;
+
+	if (!ucma_cmd_table[hdr.cmd])
+		return -ENOSYS;
+
+	ret = ucma_cmd_table[hdr.cmd](file, buf + sizeof(hdr), hdr.in, hdr.out);
+	if (!ret)
+		ret = len;
+
+	return ret;
+}
+
+static unsigned int ucma_poll(struct file *filp, struct poll_table_struct *wait)
+{
+	struct ucma_file *file = filp->private_data;
+	unsigned int mask = 0;
+
+	poll_wait(filp, &file->poll_wait, wait);
+
+	if (!list_empty(&file->event_list))
+		mask = POLLIN | POLLRDNORM;
+
+	return mask;
+}
+
+static int ucma_open(struct inode *inode, struct file *filp)
+{
+	struct ucma_file *file;
+
+	file = kmalloc(sizeof *file, GFP_KERNEL);
+	if (!file)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&file->event_list);
+	INIT_LIST_HEAD(&file->ctx_list);
+	init_waitqueue_head(&file->poll_wait);
+	mutex_init(&file->mut);
+
+	filp->private_data = file;
+	file->filp = filp;
+	return 0;
+}
+
+static int ucma_close(struct inode *inode, struct file *filp)
+{
+	struct ucma_file *file = filp->private_data;
+	struct ucma_context *ctx, *tmp;
+
+	mutex_lock(&file->mut);
+	list_for_each_entry_safe(ctx, tmp, &file->ctx_list, list) {
+		mutex_unlock(&file->mut);
+
+		mutex_lock(&mut);
+		idr_remove(&ctx_idr, ctx->id);
+		mutex_unlock(&mut);
+
+		ucma_free_ctx(ctx);
+		mutex_lock(&file->mut);
+	}
+	mutex_unlock(&file->mut);
+	kfree(file);
+	return 0;
+}
+
+static struct file_operations ucma_fops = {
+	.owner 	 = THIS_MODULE,
+	.open 	 = ucma_open,
+	.release = ucma_close,
+	.write	 = ucma_write,
+	.poll    = ucma_poll,
+};
+
+static struct miscdevice ucma_misc = {
+	.minor	= MISC_DYNAMIC_MINOR,
+	.name	= "rdma_cm",
+	.fops	= &ucma_fops,
+};
+
+static ssize_t show_abi_version(struct device *dev,
+				struct device_attribute *attr,
+				char *buf)
+{
+	return sprintf(buf, "%d\n", RDMA_USER_CM_ABI_VERSION);
+}
+static DEVICE_ATTR(abi_version, S_IRUGO, show_abi_version, NULL);
+
+static int __init ucma_init(void)
+{
+	int ret;
+
+	ret = misc_register(&ucma_misc);
+	if (ret)
+		return ret;
+
+	ret = device_create_file(ucma_misc.this_device, &dev_attr_abi_version);
+	if (ret) {
+		printk(KERN_ERR "rdma_ucm: couldn't create abi_version attr\n");
+		goto err;
+	}
+	return 0;
+err:
+	misc_deregister(&ucma_misc);
+	return ret;
+}
+
+static void __exit ucma_cleanup(void)
+{
+	device_remove_file(ucma_misc.this_device, &dev_attr_abi_version);
+	misc_deregister(&ucma_misc);
+	idr_destroy(&ctx_idr);
+}
+
+module_init(ucma_init);
+module_exit(ucma_cleanup);