user_mad.c

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/*
 * Copyright (c) 2004 Topspin Communications.  All rights reserved.
 * Copyright (c) 2005 Voltaire, Inc. All rights reserved.
 * Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
 * Copyright (c) 2008 Cisco. 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/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/dma-mapping.h>
#include <linux/poll.h>
#include <linux/mutex.h>
#include <linux/kref.h>
#include <linux/compat.h>
#include <linux/sched.h>
#include <linux/semaphore.h>
#include <linux/slab.h>

#include <asm/uaccess.h>

#include <rdma/ib_mad.h>
#include <rdma/ib_user_mad.h>

MODULE_AUTHOR("Roland Dreier");
MODULE_DESCRIPTION("InfiniBand userspace MAD packet access");
MODULE_LICENSE("Dual BSD/GPL");

enum {
    IB_UMAD_MAX_PORTS  = 64,
    IB_UMAD_MAX_AGENTS = 32,

    IB_UMAD_MAJOR      = 231,
    IB_UMAD_MINOR_BASE = 0
};

/*
 * Our lifetime rules for these structs are the following:
 * device special file is opened, we take a reference on the
 * ib_umad_port's struct ib_umad_device. We drop these
 * references in the corresponding close().
 *
 * In addition to references coming from open character devices, there
 * is one more reference to each ib_umad_device representing the
 * module's reference taken when allocating the ib_umad_device in
 * ib_umad_add_one().
 *
 * When destroying an ib_umad_device, we drop the module's reference.
 */

struct ib_umad_port {
    struct cdev           cdev;
    struct device         *dev;

    struct cdev           sm_cdev;
    struct device         *sm_dev;
    struct semaphore       sm_sem;

    struct mutex           file_mutex;
    struct list_head       file_list;

    struct ib_device      *ib_dev;
    struct ib_umad_device *umad_dev;
    int                    dev_num;
    u8                     port_num;
};

struct ib_umad_device {
    int                  start_port, end_port;
    struct kref          ref;
    struct ib_umad_port  port[0];
};

struct ib_umad_file {
    struct mutex        mutex;
    struct ib_umad_port    *port;
    struct list_head    recv_list;
    struct list_head    send_list;
    struct list_head    port_list;
    spinlock_t      send_lock;
    wait_queue_head_t   recv_wait;
    struct ib_mad_agent    *agent[IB_UMAD_MAX_AGENTS];
    int         agents_dead;
    u8          use_pkey_index;
    u8          already_used;
};

struct ib_umad_packet {
    struct ib_mad_send_buf *msg;
    struct ib_mad_recv_wc  *recv_wc;
    struct list_head   list;
    int        length;
    struct ib_user_mad mad;
};

static struct class *umad_class;

static const dev_t base_dev = MKDEV(IB_UMAD_MAJOR, IB_UMAD_MINOR_BASE);

static DEFINE_SPINLOCK(port_lock);
static DECLARE_BITMAP(dev_map, IB_UMAD_MAX_PORTS);

static void ib_umad_add_one(struct ib_device *device);
static void ib_umad_remove_one(struct ib_device *device);

static void ib_umad_release_dev(struct kref *ref)
{
    struct ib_umad_device *dev =
        container_of(ref, struct ib_umad_device, ref);

    kfree(dev);
}

static int hdr_size(struct ib_umad_file *file)
{
    return file->use_pkey_index ? sizeof (struct ib_user_mad_hdr) :
        sizeof (struct ib_user_mad_hdr_old);
}

/* caller must hold file->mutex */
static struct ib_mad_agent *__get_agent(struct ib_umad_file *file, int id)
{
    return file->agents_dead ? NULL : file->agent[id];
}

static int queue_packet(struct ib_umad_file *file,
            struct ib_mad_agent *agent,
            struct ib_umad_packet *packet)
{
    int ret = 1;

    mutex_lock(&file->mutex);

    for (packet->mad.hdr.id = 0;
         packet->mad.hdr.id < IB_UMAD_MAX_AGENTS;
         packet->mad.hdr.id++)
        if (agent == __get_agent(file, packet->mad.hdr.id)) {
            list_add_tail(&packet->list, &file->recv_list);
            wake_up_interruptible(&file->recv_wait);
            ret = 0;
            break;
        }

    mutex_unlock(&file->mutex);

    return ret;
}

static void dequeue_send(struct ib_umad_file *file,
             struct ib_umad_packet *packet)
{
    spin_lock_irq(&file->send_lock);
    list_del(&packet->list);
    spin_unlock_irq(&file->send_lock);
}

static void send_handler(struct ib_mad_agent *agent,
             struct ib_mad_send_wc *send_wc)
{
    struct ib_umad_file *file = agent->context;
    struct ib_umad_packet *packet = send_wc->send_buf->context[0];

    dequeue_send(file, packet);
    ib_destroy_ah(packet->msg->ah);
    ib_free_send_mad(packet->msg);

    if (send_wc->status == IB_WC_RESP_TIMEOUT_ERR) {
        packet->length = IB_MGMT_MAD_HDR;
        packet->mad.hdr.status = ETIMEDOUT;
        if (!queue_packet(file, agent, packet))
            return;
    }
    kfree(packet);
}

static void recv_handler(struct ib_mad_agent *agent,
             struct ib_mad_recv_wc *mad_recv_wc)
{
    struct ib_umad_file *file = agent->context;
    struct ib_umad_packet *packet;

    if (mad_recv_wc->wc->status != IB_WC_SUCCESS)
        goto err1;

    packet = kzalloc(sizeof *packet, GFP_KERNEL);
    if (!packet)
        goto err1;

    packet->length = mad_recv_wc->mad_len;
    packet->recv_wc = mad_recv_wc;

    packet->mad.hdr.status     = 0;
    packet->mad.hdr.length     = hdr_size(file) + mad_recv_wc->mad_len;
    packet->mad.hdr.qpn    = cpu_to_be32(mad_recv_wc->wc->src_qp);
    packet->mad.hdr.lid    = cpu_to_be16(mad_recv_wc->wc->slid);
    packet->mad.hdr.sl     = mad_recv_wc->wc->sl;
    packet->mad.hdr.path_bits  = mad_recv_wc->wc->dlid_path_bits;
    packet->mad.hdr.pkey_index = mad_recv_wc->wc->pkey_index;
    packet->mad.hdr.grh_present = !!(mad_recv_wc->wc->wc_flags & IB_WC_GRH);
    if (packet->mad.hdr.grh_present) {
        struct ib_ah_attr ah_attr;

        ib_init_ah_from_wc(agent->device, agent->port_num,
                   mad_recv_wc->wc, mad_recv_wc->recv_buf.grh,
                   &ah_attr);

        packet->mad.hdr.gid_index = ah_attr.grh.sgid_index;
        packet->mad.hdr.hop_limit = ah_attr.grh.hop_limit;
        packet->mad.hdr.traffic_class = ah_attr.grh.traffic_class;
        memcpy(packet->mad.hdr.gid, &ah_attr.grh.dgid, 16);
        packet->mad.hdr.flow_label = cpu_to_be32(ah_attr.grh.flow_label);
    }

    if (queue_packet(file, agent, packet))
        goto err2;
    return;

err2:
    kfree(packet);
err1:
    ib_free_recv_mad(mad_recv_wc);
}

static ssize_t copy_recv_mad(struct ib_umad_file *file, char __user *buf,
                 struct ib_umad_packet *packet, size_t count)
{
    struct ib_mad_recv_buf *recv_buf;
    int left, seg_payload, offset, max_seg_payload;

    /* We need enough room to copy the first (or only) MAD segment. */
    recv_buf = &packet->recv_wc->recv_buf;
    if ((packet->length <= sizeof (*recv_buf->mad) &&
         count < hdr_size(file) + packet->length) ||
        (packet->length > sizeof (*recv_buf->mad) &&
         count < hdr_size(file) + sizeof (*recv_buf->mad)))
        return -EINVAL;

    if (copy_to_user(buf, &packet->mad, hdr_size(file)))
        return -EFAULT;

    buf += hdr_size(file);
    seg_payload = min_t(int, packet->length, sizeof (*recv_buf->mad));
    if (copy_to_user(buf, recv_buf->mad, seg_payload))
        return -EFAULT;

    if (seg_payload < packet->length) {
        /*
         * Multipacket RMPP MAD message. Copy remainder of message.
         * Note that last segment may have a shorter payload.
         */
        if (count < hdr_size(file) + packet->length) {
            /*
             * The buffer is too small, return the first RMPP segment,
             * which includes the RMPP message length.
             */
            return -ENOSPC;
        }
        offset = ib_get_mad_data_offset(recv_buf->mad->mad_hdr.mgmt_class);
        max_seg_payload = sizeof (struct ib_mad) - offset;

        for (left = packet->length - seg_payload, buf += seg_payload;
             left; left -= seg_payload, buf += seg_payload) {
            recv_buf = container_of(recv_buf->list.next,
                        struct ib_mad_recv_buf, list);
            seg_payload = min(left, max_seg_payload);
            if (copy_to_user(buf, ((void *) recv_buf->mad) + offset,
                     seg_payload))
                return -EFAULT;
        }
    }
    return hdr_size(file) + packet->length;
}

static ssize_t copy_send_mad(struct ib_umad_file *file, char __user *buf,
                 struct ib_umad_packet *packet, size_t count)
{
    ssize_t size = hdr_size(file) + packet->length;

    if (count < size)
        return -EINVAL;

    if (copy_to_user(buf, &packet->mad, hdr_size(file)))
        return -EFAULT;

    buf += hdr_size(file);

    if (copy_to_user(buf, packet->mad.data, packet->length))
        return -EFAULT;

    return size;
}

static ssize_t ib_umad_read(struct file *filp, char __user *buf,
                size_t count, loff_t *pos)
{
    struct ib_umad_file *file = filp->private_data;
    struct ib_umad_packet *packet;
    ssize_t ret;

    if (count < hdr_size(file))
        return -EINVAL;

    mutex_lock(&file->mutex);

    while (list_empty(&file->recv_list)) {
        mutex_unlock(&file->mutex);

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

        if (wait_event_interruptible(file->recv_wait,
                         !list_empty(&file->recv_list)))
            return -ERESTARTSYS;

        mutex_lock(&file->mutex);
    }

    packet = list_entry(file->recv_list.next, struct ib_umad_packet, list);
    list_del(&packet->list);

    mutex_unlock(&file->mutex);

    if (packet->recv_wc)
        ret = copy_recv_mad(file, buf, packet, count);
    else
        ret = copy_send_mad(file, buf, packet, count);

    if (ret < 0) {
        /* Requeue packet */
        mutex_lock(&file->mutex);
        list_add(&packet->list, &file->recv_list);
        mutex_unlock(&file->mutex);
    } else {
        if (packet->recv_wc)
            ib_free_recv_mad(packet->recv_wc);
        kfree(packet);
    }
    return ret;
}

static int copy_rmpp_mad(struct ib_mad_send_buf *msg, const char __user *buf)
{
    int left, seg;

    /* Copy class specific header */
    if ((msg->hdr_len > IB_MGMT_RMPP_HDR) &&
        copy_from_user(msg->mad + IB_MGMT_RMPP_HDR, buf + IB_MGMT_RMPP_HDR,
               msg->hdr_len - IB_MGMT_RMPP_HDR))
        return -EFAULT;

    /* All headers are in place.  Copy data segments. */
    for (seg = 1, left = msg->data_len, buf += msg->hdr_len; left > 0;
         seg++, left -= msg->seg_size, buf += msg->seg_size) {
        if (copy_from_user(ib_get_rmpp_segment(msg, seg), buf,
                   min(left, msg->seg_size)))
            return -EFAULT;
    }
    return 0;
}

static int same_destination(struct ib_user_mad_hdr *hdr1,
                struct ib_user_mad_hdr *hdr2)
{
    if (!hdr1->grh_present && !hdr2->grh_present)
       return (hdr1->lid == hdr2->lid);

    if (hdr1->grh_present && hdr2->grh_present)
       return !memcmp(hdr1->gid, hdr2->gid, 16);

    return 0;
}

static int is_duplicate(struct ib_umad_file *file,
            struct ib_umad_packet *packet)
{
    struct ib_umad_packet *sent_packet;
    struct ib_mad_hdr *sent_hdr, *hdr;

    hdr = (struct ib_mad_hdr *) packet->mad.data;
    list_for_each_entry(sent_packet, &file->send_list, list) {
        sent_hdr = (struct ib_mad_hdr *) sent_packet->mad.data;

        if ((hdr->tid != sent_hdr->tid) ||
            (hdr->mgmt_class != sent_hdr->mgmt_class))
            continue;

        /*
         * No need to be overly clever here.  If two new operations have
         * the same TID, reject the second as a duplicate.  This is more
         * restrictive than required by the spec.
         */
        if (!ib_response_mad((struct ib_mad *) hdr)) {
            if (!ib_response_mad((struct ib_mad *) sent_hdr))
                return 1;
            continue;
        } else if (!ib_response_mad((struct ib_mad *) sent_hdr))
            continue;

        if (same_destination(&packet->mad.hdr, &sent_packet->mad.hdr))
            return 1;
    }

    return 0;
}

static ssize_t ib_umad_write(struct file *filp, const char __user *buf,
                 size_t count, loff_t *pos)
{
    struct ib_umad_file *file = filp->private_data;
    struct ib_umad_packet *packet;
    struct ib_mad_agent *agent;
    struct ib_ah_attr ah_attr;
    struct ib_ah *ah;
    struct ib_rmpp_mad *rmpp_mad;
    __be64 *tid;
    int ret, data_len, hdr_len, copy_offset, rmpp_active;

    if (count < hdr_size(file) + IB_MGMT_RMPP_HDR)
        return -EINVAL;

    packet = kzalloc(sizeof *packet + IB_MGMT_RMPP_HDR, GFP_KERNEL);
    if (!packet)
        return -ENOMEM;

    if (copy_from_user(&packet->mad, buf, hdr_size(file))) {
        ret = -EFAULT;
        goto err;
    }

    if (packet->mad.hdr.id >= IB_UMAD_MAX_AGENTS) {
        ret = -EINVAL;
        goto err;
    }

    buf += hdr_size(file);

    if (copy_from_user(packet->mad.data, buf, IB_MGMT_RMPP_HDR)) {
        ret = -EFAULT;
        goto err;
    }

    mutex_lock(&file->mutex);

    agent = __get_agent(file, packet->mad.hdr.id);
    if (!agent) {
        ret = -EINVAL;
        goto err_up;
    }

    memset(&ah_attr, 0, sizeof ah_attr);
    ah_attr.dlid          = be16_to_cpu(packet->mad.hdr.lid);
    ah_attr.sl            = packet->mad.hdr.sl;
    ah_attr.src_path_bits = packet->mad.hdr.path_bits;
    ah_attr.port_num      = file->port->port_num;
    if (packet->mad.hdr.grh_present) {
        ah_attr.ah_flags = IB_AH_GRH;
        memcpy(ah_attr.grh.dgid.raw, packet->mad.hdr.gid, 16);
        ah_attr.grh.sgid_index     = packet->mad.hdr.gid_index;
        ah_attr.grh.flow_label     = be32_to_cpu(packet->mad.hdr.flow_label);
        ah_attr.grh.hop_limit      = packet->mad.hdr.hop_limit;
        ah_attr.grh.traffic_class  = packet->mad.hdr.traffic_class;
    }

    ah = ib_create_ah(agent->qp->pd, &ah_attr);
    if (IS_ERR(ah)) {
        ret = PTR_ERR(ah);
        goto err_up;
    }

    rmpp_mad = (struct ib_rmpp_mad *) packet->mad.data;
    hdr_len = ib_get_mad_data_offset(rmpp_mad->mad_hdr.mgmt_class);
    if (!ib_is_mad_class_rmpp(rmpp_mad->mad_hdr.mgmt_class)) {
        copy_offset = IB_MGMT_MAD_HDR;
        rmpp_active = 0;
    } else {
        copy_offset = IB_MGMT_RMPP_HDR;
        rmpp_active = ib_get_rmpp_flags(&rmpp_mad->rmpp_hdr) &
                  IB_MGMT_RMPP_FLAG_ACTIVE;
    }

    data_len = count - hdr_size(file) - hdr_len;
    packet->msg = ib_create_send_mad(agent,
                     be32_to_cpu(packet->mad.hdr.qpn),
                     packet->mad.hdr.pkey_index, rmpp_active,
                     hdr_len, data_len, GFP_KERNEL);
    if (IS_ERR(packet->msg)) {
        ret = PTR_ERR(packet->msg);
        goto err_ah;
    }

    packet->msg->ah     = ah;
    packet->msg->timeout_ms = packet->mad.hdr.timeout_ms;
    packet->msg->retries    = packet->mad.hdr.retries;
    packet->msg->context[0] = packet;

    /* Copy MAD header.  Any RMPP header is already in place. */
    memcpy(packet->msg->mad, packet->mad.data, IB_MGMT_MAD_HDR);

    if (!rmpp_active) {
        if (copy_from_user(packet->msg->mad + copy_offset,
                   buf + copy_offset,
                   hdr_len + data_len - copy_offset)) {
            ret = -EFAULT;
            goto err_msg;
        }
    } else {
        ret = copy_rmpp_mad(packet->msg, buf);
        if (ret)
            goto err_msg;
    }

    /*
     * Set the high-order part of the transaction ID to make MADs from
     * different agents unique, and allow routing responses back to the
     * original requestor.
     */
    if (!ib_response_mad(packet->msg->mad)) {
        tid = &((struct ib_mad_hdr *) packet->msg->mad)->tid;
        *tid = cpu_to_be64(((u64) agent->hi_tid) << 32 |
                   (be64_to_cpup(tid) & 0xffffffff));
        rmpp_mad->mad_hdr.tid = *tid;
    }

    spin_lock_irq(&file->send_lock);
    ret = is_duplicate(file, packet);
    if (!ret)
        list_add_tail(&packet->list, &file->send_list);
    spin_unlock_irq(&file->send_lock);
    if (ret) {
        ret = -EINVAL;
        goto err_msg;
    }

    ret = ib_post_send_mad(packet->msg, NULL);
    if (ret)
        goto err_send;

    mutex_unlock(&file->mutex);
    return count;

err_send:
    dequeue_send(file, packet);
err_msg:
    ib_free_send_mad(packet->msg);
err_ah:
    ib_destroy_ah(ah);
err_up:
    mutex_unlock(&file->mutex);
err:
    kfree(packet);
    return ret;
}

static unsigned int ib_umad_poll(struct file *filp, struct poll_table_struct *wait)
{
    struct ib_umad_file *file = filp->private_data;

    /* we will always be able to post a MAD send */
    unsigned int mask = POLLOUT | POLLWRNORM;

    poll_wait(filp, &file->recv_wait, wait);

    if (!list_empty(&file->recv_list))
        mask |= POLLIN | POLLRDNORM;

    return mask;
}

static int ib_umad_reg_agent(struct ib_umad_file *file, void __user *arg,
                 int compat_method_mask)
{
    struct ib_user_mad_reg_req ureq;
    struct ib_mad_reg_req req;
    struct ib_mad_agent *agent = NULL;
    int agent_id;
    int ret;

    mutex_lock(&file->port->file_mutex);
    mutex_lock(&file->mutex);

    if (!file->port->ib_dev) {
        ret = -EPIPE;
        goto out;
    }

    if (copy_from_user(&ureq, arg, sizeof ureq)) {
        ret = -EFAULT;
        goto out;
    }

    if (ureq.qpn != 0 && ureq.qpn != 1) {
        ret = -EINVAL;
        goto out;
    }

    for (agent_id = 0; agent_id < IB_UMAD_MAX_AGENTS; ++agent_id)
        if (!__get_agent(file, agent_id))
            goto found;

    ret = -ENOMEM;
    goto out;

found:
    if (ureq.mgmt_class) {
        req.mgmt_class         = ureq.mgmt_class;
        req.mgmt_class_version = ureq.mgmt_class_version;
        memcpy(req.oui, ureq.oui, sizeof req.oui);

        if (compat_method_mask) {
            u32 *umm = (u32 *) ureq.method_mask;
            int i;

            for (i = 0; i < BITS_TO_LONGS(IB_MGMT_MAX_METHODS); ++i)
                req.method_mask[i] =
                    umm[i * 2] | ((u64) umm[i * 2 + 1] << 32);
        } else
            memcpy(req.method_mask, ureq.method_mask,
                   sizeof req.method_mask);
    }

    agent = ib_register_mad_agent(file->port->ib_dev, file->port->port_num,
                      ureq.qpn ? IB_QPT_GSI : IB_QPT_SMI,
                      ureq.mgmt_class ? &req : NULL,
                      ureq.rmpp_version,
                      send_handler, recv_handler, file);
    if (IS_ERR(agent)) {
        ret = PTR_ERR(agent);
        agent = NULL;
        goto out;
    }

    if (put_user(agent_id,
             (u32 __user *) (arg + offsetof(struct ib_user_mad_reg_req, id)))) {
        ret = -EFAULT;
        goto out;
    }

    if (!file->already_used) {
        file->already_used = 1;
        if (!file->use_pkey_index) {
            printk(KERN_WARNING "user_mad: process %s did not enable "
                   "P_Key index support.\n", current->comm);
            printk(KERN_WARNING "user_mad:   Documentation/infiniband/user_mad.txt "
                   "has info on the new ABI.\n");
        }
    }

    file->agent[agent_id] = agent;
    ret = 0;

out:
    mutex_unlock(&file->mutex);

    if (ret && agent)
        ib_unregister_mad_agent(agent);

    mutex_unlock(&file->port->file_mutex);

    return ret;
}

static int ib_umad_unreg_agent(struct ib_umad_file *file, u32 __user *arg)
{
    struct ib_mad_agent *agent = NULL;
    u32 id;
    int ret = 0;

    if (get_user(id, arg))
        return -EFAULT;

    mutex_lock(&file->port->file_mutex);
    mutex_lock(&file->mutex);

    if (id >= IB_UMAD_MAX_AGENTS || !__get_agent(file, id)) {
        ret = -EINVAL;
        goto out;
    }

    agent = file->agent[id];
    file->agent[id] = NULL;

out:
    mutex_unlock(&file->mutex);

    if (agent)
        ib_unregister_mad_agent(agent);

    mutex_unlock(&file->port->file_mutex);

    return ret;
}

static long ib_umad_enable_pkey(struct ib_umad_file *file)
{
    int ret = 0;

    mutex_lock(&file->mutex);
    if (file->already_used)
        ret = -EINVAL;
    else
        file->use_pkey_index = 1;
    mutex_unlock(&file->mutex);

    return ret;
}

static long ib_umad_ioctl(struct file *filp, unsigned int cmd,
              unsigned long arg)
{
    switch (cmd) {
    case IB_USER_MAD_REGISTER_AGENT:
        return ib_umad_reg_agent(filp->private_data, (void __user *) arg, 0);
    case IB_USER_MAD_UNREGISTER_AGENT:
        return ib_umad_unreg_agent(filp->private_data, (__u32 __user *) arg);
    case IB_USER_MAD_ENABLE_PKEY:
        return ib_umad_enable_pkey(filp->private_data);
    default:
        return -ENOIOCTLCMD;
    }
}

#ifdef CONFIG_COMPAT
static long ib_umad_compat_ioctl(struct file *filp, unsigned int cmd,
                 unsigned long arg)
{
    switch (cmd) {
    case IB_USER_MAD_REGISTER_AGENT:
        return ib_umad_reg_agent(filp->private_data, compat_ptr(arg), 1);
    case IB_USER_MAD_UNREGISTER_AGENT:
        return ib_umad_unreg_agent(filp->private_data, compat_ptr(arg));
    case IB_USER_MAD_ENABLE_PKEY:
        return ib_umad_enable_pkey(filp->private_data);
    default:
        return -ENOIOCTLCMD;
    }
}
#endif

/*
 * ib_umad_open() does not need the BKL:
 *
 *  - the ib_umad_port structures are properly reference counted, and
 *    everything else is purely local to the file being created, so
 *    races against other open calls are not a problem;
 *  - the ioctl method does not affect any global state outside of the
 *    file structure being operated on;
 */
static int ib_umad_open(struct inode *inode, struct file *filp)
{
    struct ib_umad_port *port;
    struct ib_umad_file *file;
    int ret;

    port = container_of(inode->i_cdev, struct ib_umad_port, cdev);
    if (port)
        kref_get(&port->umad_dev->ref);
    else
        return -ENXIO;

    mutex_lock(&port->file_mutex);

    if (!port->ib_dev) {
        ret = -ENXIO;
        goto out;
    }

    file = kzalloc(sizeof *file, GFP_KERNEL);
    if (!file) {
        kref_put(&port->umad_dev->ref, ib_umad_release_dev);
        ret = -ENOMEM;
        goto out;
    }

    mutex_init(&file->mutex);
    spin_lock_init(&file->send_lock);
    INIT_LIST_HEAD(&file->recv_list);
    INIT_LIST_HEAD(&file->send_list);
    init_waitqueue_head(&file->recv_wait);

    file->port = port;
    filp->private_data = file;

    list_add_tail(&file->port_list, &port->file_list);

    ret = nonseekable_open(inode, filp);

out:
    mutex_unlock(&port->file_mutex);
    return ret;
}

static int ib_umad_close(struct inode *inode, struct file *filp)
{
    struct ib_umad_file *file = filp->private_data;
    struct ib_umad_device *dev = file->port->umad_dev;
    struct ib_umad_packet *packet, *tmp;
    int already_dead;
    int i;

    mutex_lock(&file->port->file_mutex);
    mutex_lock(&file->mutex);

    already_dead = file->agents_dead;
    file->agents_dead = 1;

    list_for_each_entry_safe(packet, tmp, &file->recv_list, list) {
        if (packet->recv_wc)
            ib_free_recv_mad(packet->recv_wc);
        kfree(packet);
    }

    list_del(&file->port_list);

    mutex_unlock(&file->mutex);

    if (!already_dead)
        for (i = 0; i < IB_UMAD_MAX_AGENTS; ++i)
            if (file->agent[i])
                ib_unregister_mad_agent(file->agent[i]);

    mutex_unlock(&file->port->file_mutex);

    kfree(file);
    kref_put(&dev->ref, ib_umad_release_dev);

    return 0;
}

static const struct file_operations umad_fops = {
    .owner      = THIS_MODULE,
    .read       = ib_umad_read,
    .write      = ib_umad_write,
    .poll       = ib_umad_poll,
    .unlocked_ioctl = ib_umad_ioctl,
#ifdef CONFIG_COMPAT
    .compat_ioctl   = ib_umad_compat_ioctl,
#endif
    .open       = ib_umad_open,
    .release    = ib_umad_close,
    .llseek     = no_llseek,
};

static int ib_umad_sm_open(struct inode *inode, struct file *filp)
{
    struct ib_umad_port *port;
    struct ib_port_modify props = {
        .set_port_cap_mask = IB_PORT_SM
    };
    int ret;

    port = container_of(inode->i_cdev, struct ib_umad_port, sm_cdev);
    if (port)
        kref_get(&port->umad_dev->ref);
    else
        return -ENXIO;

    if (filp->f_flags & O_NONBLOCK) {
        if (down_trylock(&port->sm_sem)) {
            ret = -EAGAIN;
            goto fail;
        }
    } else {
        if (down_interruptible(&port->sm_sem)) {
            ret = -ERESTARTSYS;
            goto fail;
        }
    }

    ret = ib_modify_port(port->ib_dev, port->port_num, 0, &props);
    if (ret) {
        up(&port->sm_sem);
        goto fail;
    }

    filp->private_data = port;

    return nonseekable_open(inode, filp);

fail:
    kref_put(&port->umad_dev->ref, ib_umad_release_dev);
    return ret;
}

static int ib_umad_sm_close(struct inode *inode, struct file *filp)
{
    struct ib_umad_port *port = filp->private_data;
    struct ib_port_modify props = {
        .clr_port_cap_mask = IB_PORT_SM
    };
    int ret = 0;

    mutex_lock(&port->file_mutex);
    if (port->ib_dev)
        ret = ib_modify_port(port->ib_dev, port->port_num, 0, &props);
    mutex_unlock(&port->file_mutex);

    up(&port->sm_sem);

    kref_put(&port->umad_dev->ref, ib_umad_release_dev);

    return ret;
}

static const struct file_operations umad_sm_fops = {
    .owner   = THIS_MODULE,
    .open    = ib_umad_sm_open,
    .release = ib_umad_sm_close,
    .llseek  = no_llseek,
};

static struct ib_client umad_client = {
    .name   = "umad",
    .add    = ib_umad_add_one,
    .remove = ib_umad_remove_one
};

static ssize_t show_ibdev(struct device *dev, struct device_attribute *attr,
              char *buf)
{
    struct ib_umad_port *port = dev_get_drvdata(dev);

    if (!port)
        return -ENODEV;

    return sprintf(buf, "%s\n", port->ib_dev->name);
}
static DEVICE_ATTR(ibdev, S_IRUGO, show_ibdev, NULL);

static ssize_t show_port(struct device *dev, struct device_attribute *attr,
             char *buf)
{
    struct ib_umad_port *port = dev_get_drvdata(dev);

    if (!port)
        return -ENODEV;

    return sprintf(buf, "%d\n", port->port_num);
}
static DEVICE_ATTR(port, S_IRUGO, show_port, NULL);

static CLASS_ATTR_STRING(abi_version, S_IRUGO,
             __stringify(IB_USER_MAD_ABI_VERSION));

static dev_t overflow_maj;
static DECLARE_BITMAP(overflow_map, IB_UMAD_MAX_PORTS);
static int find_overflow_devnum(void)
{
    int ret;

    if (!overflow_maj) {
        ret = alloc_chrdev_region(&overflow_maj, 0, IB_UMAD_MAX_PORTS * 2,
                      "infiniband_mad");
        if (ret) {
            printk(KERN_ERR "user_mad: couldn't register dynamic device number\n");
            return ret;
        }
    }

    ret = find_first_zero_bit(overflow_map, IB_UMAD_MAX_PORTS);
    if (ret >= IB_UMAD_MAX_PORTS)
        return -1;

    return ret;
}

static int ib_umad_init_port(struct ib_device *device, int port_num,
                 struct ib_umad_port *port)
{
    int devnum;
    dev_t base;

    spin_lock(&port_lock);
    devnum = find_first_zero_bit(dev_map, IB_UMAD_MAX_PORTS);
    if (devnum >= IB_UMAD_MAX_PORTS) {
        spin_unlock(&port_lock);
        devnum = find_overflow_devnum();
        if (devnum < 0)
            return -1;

        spin_lock(&port_lock);
        port->dev_num = devnum + IB_UMAD_MAX_PORTS;
        base = devnum + overflow_maj;
        set_bit(devnum, overflow_map);
    } else {
        port->dev_num = devnum;
        base = devnum + base_dev;
        set_bit(devnum, dev_map);
    }
    spin_unlock(&port_lock);

    port->ib_dev   = device;
    port->port_num = port_num;
    sema_init(&port->sm_sem, 1);
    mutex_init(&port->file_mutex);
    INIT_LIST_HEAD(&port->file_list);

    cdev_init(&port->cdev, &umad_fops);
    port->cdev.owner = THIS_MODULE;
    kobject_set_name(&port->cdev.kobj, "umad%d", port->dev_num);
    if (cdev_add(&port->cdev, base, 1))
        goto err_cdev;

    port->dev = device_create(umad_class, device->dma_device,
                  port->cdev.dev, port,
                  "umad%d", port->dev_num);
    if (IS_ERR(port->dev))
        goto err_cdev;

    if (device_create_file(port->dev, &dev_attr_ibdev))
        goto err_dev;
    if (device_create_file(port->dev, &dev_attr_port))
        goto err_dev;

    base += IB_UMAD_MAX_PORTS;
    cdev_init(&port->sm_cdev, &umad_sm_fops);
    port->sm_cdev.owner = THIS_MODULE;
    kobject_set_name(&port->sm_cdev.kobj, "issm%d", port->dev_num);
    if (cdev_add(&port->sm_cdev, base, 1))
        goto err_sm_cdev;

    port->sm_dev = device_create(umad_class, device->dma_device,
                     port->sm_cdev.dev, port,
                     "issm%d", port->dev_num);
    if (IS_ERR(port->sm_dev))
        goto err_sm_cdev;

    if (device_create_file(port->sm_dev, &dev_attr_ibdev))
        goto err_sm_dev;
    if (device_create_file(port->sm_dev, &dev_attr_port))
        goto err_sm_dev;

    return 0;

err_sm_dev:
    device_destroy(umad_class, port->sm_cdev.dev);

err_sm_cdev:
    cdev_del(&port->sm_cdev);

err_dev:
    device_destroy(umad_class, port->cdev.dev);

err_cdev:
    cdev_del(&port->cdev);
    if (port->dev_num < IB_UMAD_MAX_PORTS)
        clear_bit(devnum, dev_map);
    else
        clear_bit(devnum, overflow_map);

    return -1;
}

static void ib_umad_kill_port(struct ib_umad_port *port)
{
    struct ib_umad_file *file;
    int id;

    dev_set_drvdata(port->dev,    NULL);
    dev_set_drvdata(port->sm_dev, NULL);

    device_destroy(umad_class, port->cdev.dev);
    device_destroy(umad_class, port->sm_cdev.dev);

    cdev_del(&port->cdev);
    cdev_del(&port->sm_cdev);

    mutex_lock(&port->file_mutex);

    port->ib_dev = NULL;

    list_for_each_entry(file, &port->file_list, port_list) {
        mutex_lock(&file->mutex);
        file->agents_dead = 1;
        mutex_unlock(&file->mutex);

        for (id = 0; id < IB_UMAD_MAX_AGENTS; ++id)
            if (file->agent[id])
                ib_unregister_mad_agent(file->agent[id]);
    }

    mutex_unlock(&port->file_mutex);

    if (port->dev_num < IB_UMAD_MAX_PORTS)
        clear_bit(port->dev_num, dev_map);
    else
        clear_bit(port->dev_num - IB_UMAD_MAX_PORTS, overflow_map);
}

static void ib_umad_add_one(struct ib_device *device)
{
    struct ib_umad_device *umad_dev;
    int s, e, i;

    if (rdma_node_get_transport(device->node_type) != RDMA_TRANSPORT_IB)
        return;

    if (device->node_type == RDMA_NODE_IB_SWITCH)
        s = e = 0;
    else {
        s = 1;
        e = device->phys_port_cnt;
    }

    umad_dev = kzalloc(sizeof *umad_dev +
               (e - s + 1) * sizeof (struct ib_umad_port),
               GFP_KERNEL);
    if (!umad_dev)
        return;

    kref_init(&umad_dev->ref);

    umad_dev->start_port = s;
    umad_dev->end_port   = e;

    for (i = s; i <= e; ++i) {
        umad_dev->port[i - s].umad_dev = umad_dev;

        if (ib_umad_init_port(device, i, &umad_dev->port[i - s]))
            goto err;
    }

    ib_set_client_data(device, &umad_client, umad_dev);

    return;

err:
    while (--i >= s)
        ib_umad_kill_port(&umad_dev->port[i - s]);

    kref_put(&umad_dev->ref, ib_umad_release_dev);
}

static void ib_umad_remove_one(struct ib_device *device)
{
    struct ib_umad_device *umad_dev = ib_get_client_data(device, &umad_client);
    int i;

    if (!umad_dev)
        return;

    for (i = 0; i <= umad_dev->end_port - umad_dev->start_port; ++i)
        ib_umad_kill_port(&umad_dev->port[i]);

    kref_put(&umad_dev->ref, ib_umad_release_dev);
}

static char *umad_devnode(struct device *dev, umode_t *mode)
{
    return kasprintf(GFP_KERNEL, "infiniband/%s", dev_name(dev));
}

static int __init ib_umad_init(void)
{
    int ret;

    ret = register_chrdev_region(base_dev, IB_UMAD_MAX_PORTS * 2,
                     "infiniband_mad");
    if (ret) {
        printk(KERN_ERR "user_mad: couldn't register device number\n");
        goto out;
    }

    umad_class = class_create(THIS_MODULE, "infiniband_mad");
    if (IS_ERR(umad_class)) {
        ret = PTR_ERR(umad_class);
        printk(KERN_ERR "user_mad: couldn't create class infiniband_mad\n");
        goto out_chrdev;
    }

    umad_class->devnode = umad_devnode;

    ret = class_create_file(umad_class, &class_attr_abi_version.attr);
    if (ret) {
        printk(KERN_ERR "user_mad: couldn't create abi_version attribute\n");
        goto out_class;
    }

    ret = ib_register_client(&umad_client);
    if (ret) {
        printk(KERN_ERR "user_mad: couldn't register ib_umad client\n");
        goto out_class;
    }

    return 0;

out_class:
    class_destroy(umad_class);

out_chrdev:
    unregister_chrdev_region(base_dev, IB_UMAD_MAX_PORTS * 2);

out:
    return ret;
}

static void __exit ib_umad_cleanup(void)
{
    ib_unregister_client(&umad_client);
    class_destroy(umad_class);
    unregister_chrdev_region(base_dev, IB_UMAD_MAX_PORTS * 2);
    if (overflow_maj)
        unregister_chrdev_region(overflow_maj, IB_UMAD_MAX_PORTS * 2);
}

module_init(ib_umad_init);
module_exit(ib_umad_cleanup);