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user_mad.c

/*
 * 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.
 *
 * 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.
 *
 * $Id: user_mad.c 5596 2006-03-03 01:00:07Z sean.hefty $
 */

#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/rwsem.h>
#include <linux/kref.h>
#include <linux/compat.h>

#include <asm/uaccess.h>
#include <asm/semaphore.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: each time a
 * device special file is opened, we look up the corresponding struct
 * ib_umad_port by minor in the umad_port[] table while holding the
 * port_lock.  If this lookup succeeds, we take a reference on the
 * ib_umad_port's struct ib_umad_device while still holding the
 * port_lock; if the lookup fails, we fail the open().  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 clear all of its
 * ib_umad_ports from umad_port[] while holding port_lock before
 * dropping the module's reference to the ib_umad_device.  This is
 * always safe because any open() calls will either succeed and obtain
 * a reference before we clear the umad_port[] entries, or fail after
 * we clear the umad_port[] entries.
 */

struct ib_umad_port {
      struct cdev           *dev;
      struct class_device   *class_dev;

      struct cdev           *sm_dev;
      struct class_device   *sm_class_dev;
      struct semaphore       sm_sem;

      struct rw_semaphore    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 ib_umad_port    *port;
      struct list_head  recv_list;
      struct list_head  send_list;
      struct list_head  port_list;
      spinlock_t        recv_lock;
      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 struct ib_umad_port *umad_port[IB_UMAD_MAX_PORTS];
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 port->mutex at least for reading */
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;

      down_read(&file->port->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)) {
                  spin_lock_irq(&file->recv_lock);
                  list_add_tail(&packet->list, &file->recv_list);
                  spin_unlock_irq(&file->recv_lock);
                  wake_up_interruptible(&file->recv_wait);
                  ret = 0;
                  break;
            }

      up_read(&file->port->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;

      spin_lock_irq(&file->recv_lock);

      while (list_empty(&file->recv_list)) {
            spin_unlock_irq(&file->recv_lock);

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

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

            spin_lock_irq(&file->recv_lock);
      }

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

      spin_unlock_irq(&file->recv_lock);

      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 */
            spin_lock_irq(&file->recv_lock);
            list_add(&packet->list, &file->recv_list);
            spin_unlock_irq(&file->recv_lock);
      } 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 < 0 ||
          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;
      }

      down_read(&file->port->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;

      up_read(&file->port->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:
      up_read(&file->port->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;
      int agent_id;
      int ret;

      down_write(&file->port->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);
            goto out;
      }

      if (put_user(agent_id,
                 (u32 __user *) (arg + offsetof(struct ib_user_mad_reg_req, id)))) {
            ret = -EFAULT;
            ib_unregister_mad_agent(agent);
            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:
      up_write(&file->port->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;

      down_write(&file->port->mutex);

      if (id < 0 || id >= IB_UMAD_MAX_AGENTS || !__get_agent(file, id)) {
            ret = -EINVAL;
            goto out;
      }

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

out:
      up_write(&file->port->mutex);

      if (agent)
            ib_unregister_mad_agent(agent);

      return ret;
}

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

      down_write(&file->port->mutex);
      if (file->already_used)
            ret = -EINVAL;
      else
            file->use_pkey_index = 1;
      up_write(&file->port->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

static int ib_umad_open(struct inode *inode, struct file *filp)
{
      struct ib_umad_port *port;
      struct ib_umad_file *file;
      int ret = 0;

      spin_lock(&port_lock);
      port = umad_port[iminor(inode) - IB_UMAD_MINOR_BASE];
      if (port)
            kref_get(&port->umad_dev->ref);
      spin_unlock(&port_lock);

      if (!port)
            return -ENXIO;

      down_write(&port->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;
      }

      spin_lock_init(&file->recv_lock);
      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);

out:
      up_write(&port->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;

      down_write(&file->port->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);

      downgrade_write(&file->port->mutex);

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

      up_read(&file->port->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
};

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;

      spin_lock(&port_lock);
      port = umad_port[iminor(inode) - IB_UMAD_MINOR_BASE - IB_UMAD_MAX_PORTS];
      if (port)
            kref_get(&port->umad_dev->ref);
      spin_unlock(&port_lock);

      if (!port)
            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 0;

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;

      down_write(&port->mutex);
      if (port->ib_dev)
            ret = ib_modify_port(port->ib_dev, port->port_num, 0, &props);
      up_write(&port->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
};

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

static ssize_t show_ibdev(struct class_device *class_dev, char *buf)
{
      struct ib_umad_port *port = class_get_devdata(class_dev);

      if (!port)
            return -ENODEV;

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

static ssize_t show_port(struct class_device *class_dev, char *buf)
{
      struct ib_umad_port *port = class_get_devdata(class_dev);

      if (!port)
            return -ENODEV;

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

static ssize_t show_abi_version(struct class *class, char *buf)
{
      return sprintf(buf, "%d\n", IB_USER_MAD_ABI_VERSION);
}
static CLASS_ATTR(abi_version, S_IRUGO, show_abi_version, NULL);

static int ib_umad_init_port(struct ib_device *device, int port_num,
                       struct ib_umad_port *port)
{
      spin_lock(&port_lock);
      port->dev_num = find_first_zero_bit(dev_map, IB_UMAD_MAX_PORTS);
      if (port->dev_num >= IB_UMAD_MAX_PORTS) {
            spin_unlock(&port_lock);
            return -1;
      }
      set_bit(port->dev_num, dev_map);
      spin_unlock(&port_lock);

      port->ib_dev   = device;
      port->port_num = port_num;
      init_MUTEX(&port->sm_sem);
      init_rwsem(&port->mutex);
      INIT_LIST_HEAD(&port->file_list);

      port->dev = cdev_alloc();
      if (!port->dev)
            return -1;
      port->dev->owner = THIS_MODULE;
      port->dev->ops   = &umad_fops;
      kobject_set_name(&port->dev->kobj, "umad%d", port->dev_num);
      if (cdev_add(port->dev, base_dev + port->dev_num, 1))
            goto err_cdev;

      port->class_dev = class_device_create(umad_class, NULL, port->dev->dev,
                                    device->dma_device,
                                    "umad%d", port->dev_num);
      if (IS_ERR(port->class_dev))
            goto err_cdev;

      if (class_device_create_file(port->class_dev, &class_device_attr_ibdev))
            goto err_class;
      if (class_device_create_file(port->class_dev, &class_device_attr_port))
            goto err_class;

      port->sm_dev = cdev_alloc();
      if (!port->sm_dev)
            goto err_class;
      port->sm_dev->owner = THIS_MODULE;
      port->sm_dev->ops   = &umad_sm_fops;
      kobject_set_name(&port->sm_dev->kobj, "issm%d", port->dev_num);
      if (cdev_add(port->sm_dev, base_dev + port->dev_num + IB_UMAD_MAX_PORTS, 1))
            goto err_sm_cdev;

      port->sm_class_dev = class_device_create(umad_class, NULL, port->sm_dev->dev,
                                     device->dma_device,
                                     "issm%d", port->dev_num);
      if (IS_ERR(port->sm_class_dev))
            goto err_sm_cdev;

      class_set_devdata(port->class_dev,    port);
      class_set_devdata(port->sm_class_dev, port);

      if (class_device_create_file(port->sm_class_dev, &class_device_attr_ibdev))
            goto err_sm_class;
      if (class_device_create_file(port->sm_class_dev, &class_device_attr_port))
            goto err_sm_class;

      spin_lock(&port_lock);
      umad_port[port->dev_num] = port;
      spin_unlock(&port_lock);

      return 0;

err_sm_class:
      class_device_destroy(umad_class, port->sm_dev->dev);

err_sm_cdev:
      cdev_del(port->sm_dev);

err_class:
      class_device_destroy(umad_class, port->dev->dev);

err_cdev:
      cdev_del(port->dev);
      clear_bit(port->dev_num, dev_map);

      return -1;
}

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

      class_set_devdata(port->class_dev,    NULL);
      class_set_devdata(port->sm_class_dev, NULL);

      class_device_destroy(umad_class, port->dev->dev);
      class_device_destroy(umad_class, port->sm_dev->dev);

      cdev_del(port->dev);
      cdev_del(port->sm_dev);

      spin_lock(&port_lock);
      umad_port[port->dev_num] = NULL;
      spin_unlock(&port_lock);

      down_write(&port->mutex);

      port->ib_dev = NULL;

      /*
       * Now go through the list of files attached to this port and
       * unregister all of their MAD agents.  We need to hold
       * port->mutex while doing this to avoid racing with
       * ib_umad_close(), but we can't hold the mutex for writing
       * while calling ib_unregister_mad_agent(), since that might
       * deadlock by calling back into queue_packet().  So we
       * downgrade our lock to a read lock, and then drop and
       * reacquire the write lock for the next iteration.
       *
       * We do list_del_init() on the file's list_head so that the
       * list_del in ib_umad_close() is still OK, even after the
       * file is removed from the list.
       */
      while (!list_empty(&port->file_list)) {
            file = list_entry(port->file_list.next, struct ib_umad_file,
                          port_list);

            file->agents_dead = 1;
            list_del_init(&file->port_list);

            downgrade_write(&port->mutex);

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

            up_read(&port->mutex);
            down_write(&port->mutex);
      }

      up_write(&port->mutex);

      clear_bit(port->dev_num, dev_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 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;
      }

      ret = class_create_file(umad_class, &class_attr_abi_version);
      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);
}

module_init(ib_umad_init);
module_exit(ib_umad_cleanup);

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