[mirror_ubuntu-bionic-kernel.git] / drivers / infiniband / core / ucma.c

/*
 * 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/file.h>
#include <linux/mutex.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/idr.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/miscdevice.h>
#include <linux/slab.h>
#include <linux/sysctl.h>
#include <linux/module.h>
#include <linux/nsproxy.h>

#include <rdma/rdma_user_cm.h>
#include <rdma/ib_marshall.h>
#include <rdma/rdma_cm.h>
#include <rdma/rdma_cm_ib.h>
#include <rdma/ib_addr.h>
#include <rdma/ib.h>

MODULE_AUTHOR("Sean Hefty");
MODULE_DESCRIPTION("RDMA Userspace Connection Manager Access");
MODULE_LICENSE("Dual BSD/GPL");

static unsigned int max_backlog = 1024;

static struct ctl_table_header *ucma_ctl_table_hdr;
static struct ctl_table ucma_ctl_table[] = {
        {
                .procname       = "max_backlog",
                .data           = &max_backlog,
                .maxlen         = sizeof max_backlog,
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        { }
};

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 workqueue_struct *close_wq;
};

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 list_head        mc_list;
        /* mark that device is in process of destroying the internal HW
         * resources, protected by the global mut
         */
        int                     closing;
        /* sync between removal event and id destroy, protected by file mut */
        int                     destroying;
        struct work_struct      close_work;
};

struct ucma_multicast {
        struct ucma_context     *ctx;
        int                     id;
        int                     events_reported;

        u64                     uid;
        u8                      join_state;
        struct list_head        list;
        struct sockaddr_storage addr;
};

struct ucma_event {
        struct ucma_context     *ctx;
        struct ucma_multicast   *mc;
        struct list_head        list;
        struct rdma_cm_id       *cm_id;
        struct rdma_ucm_event_resp resp;
        struct work_struct      close_work;
};

static DEFINE_MUTEX(mut);
static DEFINE_IDR(ctx_idr);
static DEFINE_IDR(multicast_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->cm_id)
                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)) {
                if (ctx->closing)
                        ctx = ERR_PTR(-EIO);
                else
                        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 void ucma_close_event_id(struct work_struct *work)
{
        struct ucma_event *uevent_close =  container_of(work, struct ucma_event, close_work);

        rdma_destroy_id(uevent_close->cm_id);
        kfree(uevent_close);
}

static void ucma_close_id(struct work_struct *work)
{
        struct ucma_context *ctx =  container_of(work, struct ucma_context, close_work);

        /* once all inflight tasks are finished, we close all underlying
         * resources. The context is still alive till its explicit destryoing
         * by its creator.
         */
        ucma_put_ctx(ctx);
        wait_for_completion(&ctx->comp);
        /* No new events will be generated after destroying the id. */
        rdma_destroy_id(ctx->cm_id);
}

static struct ucma_context *ucma_alloc_ctx(struct ucma_file *file)
{
        struct ucma_context *ctx;

        ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
        if (!ctx)
                return NULL;

        INIT_WORK(&ctx->close_work, ucma_close_id);
        atomic_set(&ctx->ref, 1);
        init_completion(&ctx->comp);
        INIT_LIST_HEAD(&ctx->mc_list);
        ctx->file = file;

        mutex_lock(&mut);
        ctx->id = idr_alloc(&ctx_idr, ctx, 0, 0, GFP_KERNEL);
        mutex_unlock(&mut);
        if (ctx->id < 0)
                goto error;

        list_add_tail(&ctx->list, &file->ctx_list);
        return ctx;

error:
        kfree(ctx);
        return NULL;
}

static struct ucma_multicast* ucma_alloc_multicast(struct ucma_context *ctx)
{
        struct ucma_multicast *mc;

        mc = kzalloc(sizeof(*mc), GFP_KERNEL);
        if (!mc)
                return NULL;

        mutex_lock(&mut);
        mc->id = idr_alloc(&multicast_idr, NULL, 0, 0, GFP_KERNEL);
        mutex_unlock(&mut);
        if (mc->id < 0)
                goto error;

        mc->ctx = ctx;
        list_add_tail(&mc->list, &ctx->mc_list);
        return mc;

error:
        kfree(mc);
        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 ib_device *device,
                               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(device, &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;
        switch (event->event) {
        case RDMA_CM_EVENT_MULTICAST_JOIN:
        case RDMA_CM_EVENT_MULTICAST_ERROR:
                uevent->mc = (struct ucma_multicast *)
                             event->param.ud.private_data;
                uevent->resp.uid = uevent->mc->uid;
                uevent->resp.id = uevent->mc->id;
                break;
        default:
                uevent->resp.uid = ctx->uid;
                uevent->resp.id = ctx->id;
                break;
        }
}

/* Called with file->mut locked for the relevant context. */
static void ucma_removal_event_handler(struct rdma_cm_id *cm_id)
{
        struct ucma_context *ctx = cm_id->context;
        struct ucma_event *con_req_eve;
        int event_found = 0;

        if (ctx->destroying)
                return;

        /* only if context is pointing to cm_id that it owns it and can be
         * queued to be closed, otherwise that cm_id is an inflight one that
         * is part of that context event list pending to be detached and
         * reattached to its new context as part of ucma_get_event,
         * handled separately below.
         */
        if (ctx->cm_id == cm_id) {
                mutex_lock(&mut);
                ctx->closing = 1;
                mutex_unlock(&mut);
                queue_work(ctx->file->close_wq, &ctx->close_work);
                return;
        }

        list_for_each_entry(con_req_eve, &ctx->file->event_list, list) {
                if (con_req_eve->cm_id == cm_id &&
                    con_req_eve->resp.event == RDMA_CM_EVENT_CONNECT_REQUEST) {
                        list_del(&con_req_eve->list);
                        INIT_WORK(&con_req_eve->close_work, ucma_close_event_id);
                        queue_work(ctx->file->close_wq, &con_req_eve->close_work);
                        event_found = 1;
                        break;
                }
        }
        if (!event_found)
                pr_err("ucma_removal_event_handler: warning: connect request event wasn't found\n");
}

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;

        mutex_lock(&ctx->file->mut);
        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->qp_type == IB_QPT_UD)
                ucma_copy_ud_event(cm_id->device, &uevent->resp.param.ud,
                                   &event->param.ud);
        else
                ucma_copy_conn_event(&uevent->resp.param.conn,
                                     &event->param.conn);

        if (event->event == RDMA_CM_EVENT_CONNECT_REQUEST) {
                if (!ctx->backlog) {
                        ret = -ENOMEM;
                        kfree(uevent);
                        goto out;
                }
                ctx->backlog--;
        } else if (!ctx->uid || ctx->cm_id != cm_id) {
                /*
                 * We ignore events for new connections until userspace has set
                 * their context.  This can only happen if an error occurs on a
                 * new connection before the user accepts it.  This is okay,
                 * since the accept will just fail later. However, we do need
                 * to release the underlying HW resources in case of a device
                 * removal event.
                 */
                if (event->event == RDMA_CM_EVENT_DEVICE_REMOVAL)
                        ucma_removal_event_handler(cm_id);

                kfree(uevent);
                goto out;
        }

        list_add_tail(&uevent->list, &ctx->file->event_list);
        wake_up_interruptible(&ctx->file->poll_wait);
        if (event->event == RDMA_CM_EVENT_DEVICE_REMOVAL)
                ucma_removal_event_handler(cm_id);
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;

        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)) {
                mutex_unlock(&file->mut);

                if (file->filp->f_flags & O_NONBLOCK)
                        return -EAGAIN;

                if (wait_event_interruptible(file->poll_wait,
                                             !list_empty(&file->event_list)))
                        return -ERESTARTSYS;

                mutex_lock(&file->mut);
        }

        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++;
        if (uevent->mc)
                uevent->mc->events_reported++;
        kfree(uevent);
done:
        mutex_unlock(&file->mut);
        return ret;
}

static int ucma_get_qp_type(struct rdma_ucm_create_id *cmd, enum ib_qp_type *qp_type)
{
        switch (cmd->ps) {
        case RDMA_PS_TCP:
                *qp_type = IB_QPT_RC;
                return 0;
        case RDMA_PS_UDP:
        case RDMA_PS_IPOIB:
                *qp_type = IB_QPT_UD;
                return 0;
        case RDMA_PS_IB:
                *qp_type = cmd->qp_type;
                return 0;
        default:
                return -EINVAL;
        }
}

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;
        struct rdma_cm_id *cm_id;
        enum ib_qp_type qp_type;
        int ret;

        if (out_len < sizeof(resp))
                return -ENOSPC;

        if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
                return -EFAULT;

        ret = ucma_get_qp_type(&cmd, &qp_type);
        if (ret)
                return ret;

        mutex_lock(&file->mut);
        ctx = ucma_alloc_ctx(file);
        mutex_unlock(&file->mut);
        if (!ctx)
                return -ENOMEM;

        ctx->uid = cmd.uid;
        cm_id = rdma_create_id(current->nsproxy->net_ns,
                               ucma_event_handler, ctx, cmd.ps, qp_type);
        if (IS_ERR(cm_id)) {
                ret = PTR_ERR(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;
        }

        ctx->cm_id = cm_id;
        return 0;

err2:
        rdma_destroy_id(cm_id);
err1:
        mutex_lock(&mut);
        idr_remove(&ctx_idr, ctx->id);
        mutex_unlock(&mut);
        mutex_lock(&file->mut);
        list_del(&ctx->list);
        mutex_unlock(&file->mut);
        kfree(ctx);
        return ret;
}

static void ucma_cleanup_multicast(struct ucma_context *ctx)
{
        struct ucma_multicast *mc, *tmp;

        mutex_lock(&mut);
        list_for_each_entry_safe(mc, tmp, &ctx->mc_list, list) {
                list_del(&mc->list);
                idr_remove(&multicast_idr, mc->id);
                kfree(mc);
        }
        mutex_unlock(&mut);
}

static void ucma_cleanup_mc_events(struct ucma_multicast *mc)
{
        struct ucma_event *uevent, *tmp;

        list_for_each_entry_safe(uevent, tmp, &mc->ctx->file->event_list, list) {
                if (uevent->mc != mc)
                        continue;

                list_del(&uevent->list);
                kfree(uevent);
        }
}

/*
 * ucma_free_ctx is called after the underlying rdma CM-ID is destroyed. At
 * this point, no new events will be reported from the hardware. However, we
 * still need to cleanup the UCMA context for this ID. Specifically, there
 * might be events that have not yet been consumed by the user space software.
 * These might include pending connect requests which we have not completed
 * processing.  We cannot call rdma_destroy_id while holding the lock of the
 * context (file->mut), as it might cause a deadlock. We therefore extract all
 * relevant events from the context pending events list while holding the
 * mutex. After that we release them as needed.
 */
static int ucma_free_ctx(struct ucma_context *ctx)
{
        int events_reported;
        struct ucma_event *uevent, *tmp;
        LIST_HEAD(list);


        ucma_cleanup_multicast(ctx);

        /* Cleanup events not yet reported to the user. */
        mutex_lock(&ctx->file->mut);
        list_for_each_entry_safe(uevent, tmp, &ctx->file->event_list, list) {
                if (uevent->ctx == ctx)
                        list_move_tail(&uevent->list, &list);
        }
        list_del(&ctx->list);
        mutex_unlock(&ctx->file->mut);

        list_for_each_entry_safe(uevent, tmp, &list, list) {
                list_del(&uevent->list);
                if (uevent->resp.event == RDMA_CM_EVENT_CONNECT_REQUEST)
                        rdma_destroy_id(uevent->cm_id);
                kfree(uevent);
        }

        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);

        mutex_lock(&ctx->file->mut);
        ctx->destroying = 1;
        mutex_unlock(&ctx->file->mut);

        flush_workqueue(ctx->file->close_wq);
        /* At this point it's guaranteed that there is no inflight
         * closing task */
        mutex_lock(&mut);
        if (!ctx->closing) {
                mutex_unlock(&mut);
                ucma_put_ctx(ctx);
                wait_for_completion(&ctx->comp);
                rdma_destroy_id(ctx->cm_id);
        } else {
                mutex_unlock(&mut);
        }

        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_ip(struct ucma_file *file, const char __user *inbuf,
                              int in_len, int out_len)
{
        struct rdma_ucm_bind_ip cmd;
        struct ucma_context *ctx;
        int ret;

        if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
                return -EFAULT;

        if (!rdma_addr_size_in6(&cmd.addr))
                return -EINVAL;

        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_bind(struct ucma_file *file, const char __user *inbuf,
                         int in_len, int out_len)
{
        struct rdma_ucm_bind cmd;
        struct ucma_context *ctx;
        int ret;

        if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
                return -EFAULT;

        if (cmd.reserved || !cmd.addr_size ||
            cmd.addr_size != rdma_addr_size_kss(&cmd.addr))
                return -EINVAL;

        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_ip(struct ucma_file *file,
                               const char __user *inbuf,
                               int in_len, int out_len)
{
        struct rdma_ucm_resolve_ip cmd;
        struct ucma_context *ctx;
        int ret;

        if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
                return -EFAULT;

        if ((cmd.src_addr.sin6_family && !rdma_addr_size_in6(&cmd.src_addr)) ||
            !rdma_addr_size_in6(&cmd.dst_addr))
                return -EINVAL;

        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_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;

        if (cmd.reserved ||
            (cmd.src_size && (cmd.src_size != rdma_addr_size_kss(&cmd.src_addr))) ||
            !cmd.dst_size || (cmd.dst_size != rdma_addr_size_kss(&cmd.dst_addr)))
                return -EINVAL;

        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;
                rdma_addr_get_dgid(dev_addr,
                                   (union ib_gid *) &resp->ib_route[0].dgid);
                rdma_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 void ucma_copy_iboe_route(struct rdma_ucm_query_route_resp *resp,
                                 struct rdma_route *route)
{

        resp->num_paths = route->num_paths;
        switch (route->num_paths) {
        case 0:
                rdma_ip2gid((struct sockaddr *)&route->addr.dst_addr,
                            (union ib_gid *)&resp->ib_route[0].dgid);
                rdma_ip2gid((struct sockaddr *)&route->addr.src_addr,
                            (union ib_gid *)&resp->ib_route[0].sgid);
                resp->ib_route[0].pkey = cpu_to_be16(0xffff);
                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 void ucma_copy_iw_route(struct rdma_ucm_query_route_resp *resp,
                               struct rdma_route *route)
{
        struct rdma_dev_addr *dev_addr;

        dev_addr = &route->addr.dev_addr;
        rdma_addr_get_dgid(dev_addr, (union ib_gid *) &resp->ib_route[0].dgid);
        rdma_addr_get_sgid(dev_addr, (union ib_gid *) &resp->ib_route[0].sgid);
}

static ssize_t ucma_query_route(struct ucma_file *file,
                                const char __user *inbuf,
                                int in_len, int out_len)
{
        struct rdma_ucm_query 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 = (struct sockaddr *) &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 = (struct sockaddr *) &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 = (__force __u64) ctx->cm_id->device->node_guid;
        resp.port_num = ctx->cm_id->port_num;

        if (rdma_cap_ib_sa(ctx->cm_id->device, ctx->cm_id->port_num))
                ucma_copy_ib_route(&resp, &ctx->cm_id->route);
        else if (rdma_protocol_roce(ctx->cm_id->device, ctx->cm_id->port_num))
                ucma_copy_iboe_route(&resp, &ctx->cm_id->route);
        else if (rdma_protocol_iwarp(ctx->cm_id->device, ctx->cm_id->port_num))
                ucma_copy_iw_route(&resp, &ctx->cm_id->route);

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_query_device_addr(struct rdma_cm_id *cm_id,
                                   struct rdma_ucm_query_addr_resp *resp)
{
        if (!cm_id->device)
                return;

        resp->node_guid = (__force __u64) cm_id->device->node_guid;
        resp->port_num = cm_id->port_num;
        resp->pkey = (__force __u16) cpu_to_be16(
                     ib_addr_get_pkey(&cm_id->route.addr.dev_addr));
}

static ssize_t ucma_query_addr(struct ucma_context *ctx,
                               void __user *response, int out_len)
{
        struct rdma_ucm_query_addr_resp resp;
        struct sockaddr *addr;
        int ret = 0;

        if (out_len < sizeof(resp))
                return -ENOSPC;

        memset(&resp, 0, sizeof resp);

        addr = (struct sockaddr *) &ctx->cm_id->route.addr.src_addr;
        resp.src_size = rdma_addr_size(addr);
        memcpy(&resp.src_addr, addr, resp.src_size);

        addr = (struct sockaddr *) &ctx->cm_id->route.addr.dst_addr;
        resp.dst_size = rdma_addr_size(addr);
        memcpy(&resp.dst_addr, addr, resp.dst_size);

        ucma_query_device_addr(ctx->cm_id, &resp);

        if (copy_to_user(response, &resp, sizeof(resp)))
                ret = -EFAULT;

        return ret;
}

static ssize_t ucma_query_path(struct ucma_context *ctx,
                               void __user *response, int out_len)
{
        struct rdma_ucm_query_path_resp *resp;
        int i, ret = 0;

        if (out_len < sizeof(*resp))
                return -ENOSPC;

        resp = kzalloc(out_len, GFP_KERNEL);
        if (!resp)
                return -ENOMEM;

        resp->num_paths = ctx->cm_id->route.num_paths;
        for (i = 0, out_len -= sizeof(*resp);
             i < resp->num_paths && out_len > sizeof(struct ib_path_rec_data);
             i++, out_len -= sizeof(struct ib_path_rec_data)) {
                struct sa_path_rec *rec = &ctx->cm_id->route.path_rec[i];

                resp->path_data[i].flags = IB_PATH_GMP | IB_PATH_PRIMARY |
                                           IB_PATH_BIDIRECTIONAL;
                if (rec->rec_type == SA_PATH_REC_TYPE_OPA) {
                        struct sa_path_rec ib;

                        sa_convert_path_opa_to_ib(&ib, rec);
                        ib_sa_pack_path(&ib, &resp->path_data[i].path_rec);

                } else {
                        ib_sa_pack_path(rec, &resp->path_data[i].path_rec);
                }
        }

        if (copy_to_user(response, resp,
                         sizeof(*resp) + (i * sizeof(struct ib_path_rec_data))))
                ret = -EFAULT;

        kfree(resp);
        return ret;
}

static ssize_t ucma_query_gid(struct ucma_context *ctx,
                              void __user *response, int out_len)
{
        struct rdma_ucm_query_addr_resp resp;
        struct sockaddr_ib *addr;
        int ret = 0;

        if (out_len < sizeof(resp))
                return -ENOSPC;

        memset(&resp, 0, sizeof resp);

        ucma_query_device_addr(ctx->cm_id, &resp);

        addr = (struct sockaddr_ib *) &resp.src_addr;
        resp.src_size = sizeof(*addr);
        if (ctx->cm_id->route.addr.src_addr.ss_family == AF_IB) {
                memcpy(addr, &ctx->cm_id->route.addr.src_addr, resp.src_size);
        } else {
                addr->sib_family = AF_IB;
                addr->sib_pkey = (__force __be16) resp.pkey;
                rdma_addr_get_sgid(&ctx->cm_id->route.addr.dev_addr,
                                   (union ib_gid *) &addr->sib_addr);
                addr->sib_sid = rdma_get_service_id(ctx->cm_id, (struct sockaddr *)
                                                    &ctx->cm_id->route.addr.src_addr);
        }

        addr = (struct sockaddr_ib *) &resp.dst_addr;
        resp.dst_size = sizeof(*addr);
        if (ctx->cm_id->route.addr.dst_addr.ss_family == AF_IB) {
                memcpy(addr, &ctx->cm_id->route.addr.dst_addr, resp.dst_size);
        } else {
                addr->sib_family = AF_IB;
                addr->sib_pkey = (__force __be16) resp.pkey;
                rdma_addr_get_dgid(&ctx->cm_id->route.addr.dev_addr,
                                   (union ib_gid *) &addr->sib_addr);
                addr->sib_sid = rdma_get_service_id(ctx->cm_id, (struct sockaddr *)
                                                    &ctx->cm_id->route.addr.dst_addr);
        }

        if (copy_to_user(response, &resp, sizeof(resp)))
                ret = -EFAULT;

        return ret;
}

static ssize_t ucma_query(struct ucma_file *file,
                          const char __user *inbuf,
                          int in_len, int out_len)
{
        struct rdma_ucm_query cmd;
        struct ucma_context *ctx;
        void __user *response;
        int ret;

        if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
                return -EFAULT;

        response = (void __user *)(unsigned long) cmd.response;
        ctx = ucma_get_ctx(file, cmd.id);
        if (IS_ERR(ctx))
                return PTR_ERR(ctx);

        switch (cmd.option) {
        case RDMA_USER_CM_QUERY_ADDR:
                ret = ucma_query_addr(ctx, response, out_len);
                break;
        case RDMA_USER_CM_QUERY_PATH:
                ret = ucma_query_path(ctx, response, out_len);
                break;
        case RDMA_USER_CM_QUERY_GID:
                ret = ucma_query_gid(ctx, response, out_len);
                break;
        default:
                ret = -ENOSYS;
                break;
        }

        ucma_put_ctx(ctx);
        return ret;
}

static void ucma_copy_conn_param(struct rdma_cm_id *id,
                                 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;
        dst->qkey = (id->route.addr.src_addr.ss_family == AF_IB) ? src->qkey : 0;
}

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(ctx->cm_id, &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 < max_backlog ?
                       cmd.backlog : 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) {
                ucma_copy_conn_param(ctx->cm_id, &conn_param, &cmd.conn_param);
                mutex_lock(&file->mut);
                ret = rdma_accept(ctx->cm_id, &conn_param);
                if (!ret)
                        ctx->uid = cmd.uid;
                mutex_unlock(&file->mut);
        } 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;

        if (cmd.qp_state > IB_QPS_ERR)
                return -EINVAL;

        ctx = ucma_get_ctx(file, cmd.id);
        if (IS_ERR(ctx))
                return PTR_ERR(ctx);

        if (!ctx->cm_id->device) {
                ret = -EINVAL;
                goto out;
        }

        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(ctx->cm_id->device, &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 int ucma_set_option_id(struct ucma_context *ctx, int optname,
                              void *optval, size_t optlen)
{
        int ret = 0;

        switch (optname) {
        case RDMA_OPTION_ID_TOS:
                if (optlen != sizeof(u8)) {
                        ret = -EINVAL;
                        break;
                }
                rdma_set_service_type(ctx->cm_id, *((u8 *) optval));
                break;
        case RDMA_OPTION_ID_REUSEADDR:
                if (optlen != sizeof(int)) {
                        ret = -EINVAL;
                        break;
                }
                ret = rdma_set_reuseaddr(ctx->cm_id, *((int *) optval) ? 1 : 0);
                break;
        case RDMA_OPTION_ID_AFONLY:
                if (optlen != sizeof(int)) {
                        ret = -EINVAL;
                        break;
                }
                ret = rdma_set_afonly(ctx->cm_id, *((int *) optval) ? 1 : 0);
                break;
        default:
                ret = -ENOSYS;
        }

        return ret;
}

static int ucma_set_ib_path(struct ucma_context *ctx,
                            struct ib_path_rec_data *path_data, size_t optlen)
{
        struct sa_path_rec sa_path;
        struct rdma_cm_event event;
        int ret;

        if (optlen % sizeof(*path_data))
                return -EINVAL;

        for (; optlen; optlen -= sizeof(*path_data), path_data++) {
                if (path_data->flags == (IB_PATH_GMP | IB_PATH_PRIMARY |
                                         IB_PATH_BIDIRECTIONAL))
                        break;
        }

        if (!optlen)
                return -EINVAL;

        if (!ctx->cm_id->device)
                return -EINVAL;

        memset(&sa_path, 0, sizeof(sa_path));

        sa_path.rec_type = SA_PATH_REC_TYPE_IB;
        ib_sa_unpack_path(path_data->path_rec, &sa_path);

        if (rdma_cap_opa_ah(ctx->cm_id->device, ctx->cm_id->port_num)) {
                struct sa_path_rec opa;

                sa_convert_path_ib_to_opa(&opa, &sa_path);
                ret = rdma_set_ib_paths(ctx->cm_id, &opa, 1);
        } else {
                ret = rdma_set_ib_paths(ctx->cm_id, &sa_path, 1);
        }
        if (ret)
                return ret;

        memset(&event, 0, sizeof event);
        event.event = RDMA_CM_EVENT_ROUTE_RESOLVED;
        return ucma_event_handler(ctx->cm_id, &event);
}

static int ucma_set_option_ib(struct ucma_context *ctx, int optname,
                              void *optval, size_t optlen)
{
        int ret;

        switch (optname) {
        case RDMA_OPTION_IB_PATH:
                ret = ucma_set_ib_path(ctx, optval, optlen);
                break;
        default:
                ret = -ENOSYS;
        }

        return ret;
}

static int ucma_set_option_level(struct ucma_context *ctx, int level,
                                 int optname, void *optval, size_t optlen)
{
        int ret;

        switch (level) {
        case RDMA_OPTION_ID:
                ret = ucma_set_option_id(ctx, optname, optval, optlen);
                break;
        case RDMA_OPTION_IB:
                ret = ucma_set_option_ib(ctx, optname, optval, optlen);
                break;
        default:
                ret = -ENOSYS;
        }

        return ret;
}

static ssize_t ucma_set_option(struct ucma_file *file, const char __user *inbuf,
                               int in_len, int out_len)
{
        struct rdma_ucm_set_option cmd;
        struct ucma_context *ctx;
        void *optval;
        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 (unlikely(cmd.optlen > KMALLOC_MAX_SIZE))
                return -EINVAL;

        optval = memdup_user((void __user *) (unsigned long) cmd.optval,
                             cmd.optlen);
        if (IS_ERR(optval)) {
                ret = PTR_ERR(optval);
                goto out;
        }

        ret = ucma_set_option_level(ctx, cmd.level, cmd.optname, optval,
                                    cmd.optlen);
        kfree(optval);

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 = -EINVAL;

        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 (ctx->cm_id->device)
                ret = rdma_notify(ctx->cm_id, (enum ib_event_type)cmd.event);

        ucma_put_ctx(ctx);
        return ret;
}

static ssize_t ucma_process_join(struct ucma_file *file,
                                 struct rdma_ucm_join_mcast *cmd,  int out_len)
{
        struct rdma_ucm_create_id_resp resp;
        struct ucma_context *ctx;
        struct ucma_multicast *mc;
        struct sockaddr *addr;
        int ret;
        u8 join_state;

        if (out_len < sizeof(resp))
                return -ENOSPC;

        addr = (struct sockaddr *) &cmd->addr;
        if (cmd->addr_size != rdma_addr_size(addr))
                return -EINVAL;

        if (cmd->join_flags == RDMA_MC_JOIN_FLAG_FULLMEMBER)
                join_state = BIT(FULLMEMBER_JOIN);
        else if (cmd->join_flags == RDMA_MC_JOIN_FLAG_SENDONLY_FULLMEMBER)
                join_state = BIT(SENDONLY_FULLMEMBER_JOIN);
        else
                return -EINVAL;

        ctx = ucma_get_ctx(file, cmd->id);
        if (IS_ERR(ctx))
                return PTR_ERR(ctx);

        mutex_lock(&file->mut);
        mc = ucma_alloc_multicast(ctx);
        if (!mc) {
                ret = -ENOMEM;
                goto err1;
        }
        mc->join_state = join_state;
        mc->uid = cmd->uid;
        memcpy(&mc->addr, addr, cmd->addr_size);
        ret = rdma_join_multicast(ctx->cm_id, (struct sockaddr *)&mc->addr,
                                  join_state, mc);
        if (ret)
                goto err2;

        resp.id = mc->id;
        if (copy_to_user((void __user *)(unsigned long) cmd->response,
                         &resp, sizeof(resp))) {
                ret = -EFAULT;
                goto err3;
        }

        mutex_lock(&mut);
        idr_replace(&multicast_idr, mc, mc->id);
        mutex_unlock(&mut);

        mutex_unlock(&file->mut);
        ucma_put_ctx(ctx);
        return 0;

err3:
        rdma_leave_multicast(ctx->cm_id, (struct sockaddr *) &mc->addr);
        ucma_cleanup_mc_events(mc);
err2:
        mutex_lock(&mut);
        idr_remove(&multicast_idr, mc->id);
        mutex_unlock(&mut);
        list_del(&mc->list);
        kfree(mc);
err1:
        mutex_unlock(&file->mut);
        ucma_put_ctx(ctx);
        return ret;
}

static ssize_t ucma_join_ip_multicast(struct ucma_file *file,
                                      const char __user *inbuf,
                                      int in_len, int out_len)
{
        struct rdma_ucm_join_ip_mcast cmd;
        struct rdma_ucm_join_mcast join_cmd;

        if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
                return -EFAULT;

        join_cmd.response = cmd.response;
        join_cmd.uid = cmd.uid;
        join_cmd.id = cmd.id;
        join_cmd.addr_size = rdma_addr_size_in6(&cmd.addr);
        if (!join_cmd.addr_size)
                return -EINVAL;

        join_cmd.join_flags = RDMA_MC_JOIN_FLAG_FULLMEMBER;
        memcpy(&join_cmd.addr, &cmd.addr, join_cmd.addr_size);

        return ucma_process_join(file, &join_cmd, out_len);
}

static ssize_t ucma_join_multicast(struct ucma_file *file,
                                   const char __user *inbuf,
                                   int in_len, int out_len)
{
        struct rdma_ucm_join_mcast cmd;

        if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
                return -EFAULT;

        if (!rdma_addr_size_kss(&cmd.addr))
                return -EINVAL;

        return ucma_process_join(file, &cmd, out_len);
}

static ssize_t ucma_leave_multicast(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_multicast *mc;
        int ret = 0;

        if (out_len < sizeof(resp))
                return -ENOSPC;

        if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
                return -EFAULT;

        mutex_lock(&mut);
        mc = idr_find(&multicast_idr, cmd.id);
        if (!mc)
                mc = ERR_PTR(-ENOENT);
        else if (mc->ctx->file != file)
                mc = ERR_PTR(-EINVAL);
        else if (!atomic_inc_not_zero(&mc->ctx->ref))
                mc = ERR_PTR(-ENXIO);
        else
                idr_remove(&multicast_idr, mc->id);
        mutex_unlock(&mut);

        if (IS_ERR(mc)) {
                ret = PTR_ERR(mc);
                goto out;
        }

        rdma_leave_multicast(mc->ctx->cm_id, (struct sockaddr *) &mc->addr);
        mutex_lock(&mc->ctx->file->mut);
        ucma_cleanup_mc_events(mc);
        list_del(&mc->list);
        mutex_unlock(&mc->ctx->file->mut);

        ucma_put_ctx(mc->ctx);
        resp.events_reported = mc->events_reported;
        kfree(mc);

        if (copy_to_user((void __user *)(unsigned long)cmd.response,
                         &resp, sizeof(resp)))
                ret = -EFAULT;
out:
        return ret;
}

static void ucma_lock_files(struct ucma_file *file1, struct ucma_file *file2)
{
        /* Acquire mutex's based on pointer comparison to prevent deadlock. */
        if (file1 < file2) {
                mutex_lock(&file1->mut);
                mutex_lock_nested(&file2->mut, SINGLE_DEPTH_NESTING);
        } else {
                mutex_lock(&file2->mut);
                mutex_lock_nested(&file1->mut, SINGLE_DEPTH_NESTING);
        }
}

static void ucma_unlock_files(struct ucma_file *file1, struct ucma_file *file2)
{
        if (file1 < file2) {
                mutex_unlock(&file2->mut);
                mutex_unlock(&file1->mut);
        } else {
                mutex_unlock(&file1->mut);
                mutex_unlock(&file2->mut);
        }
}

static void ucma_move_events(struct ucma_context *ctx, struct ucma_file *file)
{
        struct ucma_event *uevent, *tmp;

        list_for_each_entry_safe(uevent, tmp, &ctx->file->event_list, list)
                if (uevent->ctx == ctx)
                        list_move_tail(&uevent->list, &file->event_list);
}

static ssize_t ucma_migrate_id(struct ucma_file *new_file,
                               const char __user *inbuf,
                               int in_len, int out_len)
{
        struct rdma_ucm_migrate_id cmd;
        struct rdma_ucm_migrate_resp resp;
        struct ucma_context *ctx;
        struct fd f;
        struct ucma_file *cur_file;
        int ret = 0;

        if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
                return -EFAULT;

        /* Get current fd to protect against it being closed */
        f = fdget(cmd.fd);
        if (!f.file)
                return -ENOENT;

        /* Validate current fd and prevent destruction of id. */
        ctx = ucma_get_ctx(f.file->private_data, cmd.id);
        if (IS_ERR(ctx)) {
                ret = PTR_ERR(ctx);
                goto file_put;
        }

        cur_file = ctx->file;
        if (cur_file == new_file) {
                resp.events_reported = ctx->events_reported;
                goto response;
        }

        /*
         * Migrate events between fd's, maintaining order, and avoiding new
         * events being added before existing events.
         */
        ucma_lock_files(cur_file, new_file);
        mutex_lock(&mut);

        list_move_tail(&ctx->list, &new_file->ctx_list);
        ucma_move_events(ctx, new_file);
        ctx->file = new_file;
        resp.events_reported = ctx->events_reported;

        mutex_unlock(&mut);
        ucma_unlock_files(cur_file, new_file);

response:
        if (copy_to_user((void __user *)(unsigned long)cmd.response,
                         &resp, sizeof(resp)))
                ret = -EFAULT;

        ucma_put_ctx(ctx);
file_put:
        fdput(f);
        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_IP]       = ucma_bind_ip,
        [RDMA_USER_CM_CMD_RESOLVE_IP]    = ucma_resolve_ip,
        [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]    = ucma_set_option,
        [RDMA_USER_CM_CMD_NOTIFY]        = ucma_notify,
        [RDMA_USER_CM_CMD_JOIN_IP_MCAST] = ucma_join_ip_multicast,
        [RDMA_USER_CM_CMD_LEAVE_MCAST]   = ucma_leave_multicast,
        [RDMA_USER_CM_CMD_MIGRATE_ID]    = ucma_migrate_id,
        [RDMA_USER_CM_CMD_QUERY]         = ucma_query,
        [RDMA_USER_CM_CMD_BIND]          = ucma_bind,
        [RDMA_USER_CM_CMD_RESOLVE_ADDR]  = ucma_resolve_addr,
        [RDMA_USER_CM_CMD_JOIN_MCAST]    = ucma_join_multicast
};

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 (!ib_safe_file_access(filp)) {
                pr_err_once("ucma_write: process %d (%s) changed security contexts after opening file descriptor, this is not allowed.\n",
                            task_tgid_vnr(current), current->comm);
                return -EACCES;
        }

        if (len < sizeof(hdr))
                return -EINVAL;

        if (copy_from_user(&hdr, buf, sizeof(hdr)))
                return -EFAULT;

        if (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;
}

/*
 * ucma_open() does not need the BKL:
 *
 *  - no global state is referred to;
 *  - there is no ioctl method to race against;
 *  - no further module initialization is required for open to work
 *    after the device is registered.
 */
static int ucma_open(struct inode *inode, struct file *filp)
{
        struct ucma_file *file;

        file = kmalloc(sizeof *file, GFP_KERNEL);
        if (!file)
                return -ENOMEM;

        file->close_wq = alloc_ordered_workqueue("ucma_close_id",
                                                 WQ_MEM_RECLAIM);
        if (!file->close_wq) {
                kfree(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 nonseekable_open(inode, filp);
}

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) {
                ctx->destroying = 1;
                mutex_unlock(&file->mut);

                mutex_lock(&mut);
                idr_remove(&ctx_idr, ctx->id);
                mutex_unlock(&mut);

                flush_workqueue(file->close_wq);
                /* At that step once ctx was marked as destroying and workqueue
                 * was flushed we are safe from any inflights handlers that
                 * might put other closing task.
                 */
                mutex_lock(&mut);
                if (!ctx->closing) {
                        mutex_unlock(&mut);
                        /* rdma_destroy_id ensures that no event handlers are
                         * inflight for that id before releasing it.
                         */
                        rdma_destroy_id(ctx->cm_id);
                } else {
                        mutex_unlock(&mut);
                }

                ucma_free_ctx(ctx);
                mutex_lock(&file->mut);
        }
        mutex_unlock(&file->mut);
        destroy_workqueue(file->close_wq);
        kfree(file);
        return 0;
}

static const struct file_operations ucma_fops = {
        .owner   = THIS_MODULE,
        .open    = ucma_open,
        .release = ucma_close,
        .write   = ucma_write,
        .poll    = ucma_poll,
        .llseek  = no_llseek,
};

static struct miscdevice ucma_misc = {
        .minor          = MISC_DYNAMIC_MINOR,
        .name           = "rdma_cm",
        .nodename       = "infiniband/rdma_cm",
        .mode           = 0666,
        .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) {
                pr_err("rdma_ucm: couldn't create abi_version attr\n");
                goto err1;
        }

        ucma_ctl_table_hdr = register_net_sysctl(&init_net, "net/rdma_ucm", ucma_ctl_table);
        if (!ucma_ctl_table_hdr) {
                pr_err("rdma_ucm: couldn't register sysctl paths\n");
                ret = -ENOMEM;
                goto err2;
        }
        return 0;
err2:
        device_remove_file(ucma_misc.this_device, &dev_attr_abi_version);
err1:
        misc_deregister(&ucma_misc);
        return ret;
}

static void __exit ucma_cleanup(void)
{
        unregister_net_sysctl_table(ucma_ctl_table_hdr);
        device_remove_file(ucma_misc.this_device, &dev_attr_abi_version);
        misc_deregister(&ucma_misc);
        idr_destroy(&ctx_idr);
        idr_destroy(&multicast_idr);
}

module_init(ucma_init);
module_exit(ucma_cleanup);