multicast.c

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/*
 * Copyright (c) 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/dma-mapping.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/bitops.h>
#include <linux/random.h>

#include <rdma/ib_cache.h>
#include "sa.h"

static void mcast_add_one(struct ib_device *device);
static void mcast_remove_one(struct ib_device *device);

static struct ib_client mcast_client = {
    .name   = "ib_multicast",
    .add    = mcast_add_one,
    .remove = mcast_remove_one
};

static struct ib_sa_client  sa_client;
static struct workqueue_struct  *mcast_wq;
static union ib_gid mgid0;

struct mcast_device;

struct mcast_port {
    struct mcast_device *dev;
    spinlock_t      lock;
    struct rb_root      table;
    atomic_t        refcount;
    struct completion   comp;
    u8          port_num;
};

struct mcast_device {
    struct ib_device    *device;
    struct ib_event_handler event_handler;
    int         start_port;
    int         end_port;
    struct mcast_port   port[0];
};

enum mcast_state {
    MCAST_JOINING,
    MCAST_MEMBER,
    MCAST_ERROR,
};

enum mcast_group_state {
    MCAST_IDLE,
    MCAST_BUSY,
    MCAST_GROUP_ERROR,
    MCAST_PKEY_EVENT
};

enum {
    MCAST_INVALID_PKEY_INDEX = 0xFFFF
};

struct mcast_member;

struct mcast_group {
    struct ib_sa_mcmember_rec rec;
    struct rb_node      node;
    struct mcast_port   *port;
    spinlock_t      lock;
    struct work_struct  work;
    struct list_head    pending_list;
    struct list_head    active_list;
    struct mcast_member *last_join;
    int         members[3];
    atomic_t        refcount;
    enum mcast_group_state  state;
    struct ib_sa_query  *query;
    int         query_id;
    u16         pkey_index;
    u8          leave_state;
    int         retries;
};

struct mcast_member {
    struct ib_sa_multicast  multicast;
    struct ib_sa_client *client;
    struct mcast_group  *group;
    struct list_head    list;
    enum mcast_state    state;
    atomic_t        refcount;
    struct completion   comp;
};

static void join_handler(int status, struct ib_sa_mcmember_rec *rec,
             void *context);
static void leave_handler(int status, struct ib_sa_mcmember_rec *rec,
              void *context);

static struct mcast_group *mcast_find(struct mcast_port *port,
                      union ib_gid *mgid)
{
    struct rb_node *node = port->table.rb_node;
    struct mcast_group *group;
    int ret;

    while (node) {
        group = rb_entry(node, struct mcast_group, node);
        ret = memcmp(mgid->raw, group->rec.mgid.raw, sizeof *mgid);
        if (!ret)
            return group;

        if (ret < 0)
            node = node->rb_left;
        else
            node = node->rb_right;
    }
    return NULL;
}

static struct mcast_group *mcast_insert(struct mcast_port *port,
                    struct mcast_group *group,
                    int allow_duplicates)
{
    struct rb_node **link = &port->table.rb_node;
    struct rb_node *parent = NULL;
    struct mcast_group *cur_group;
    int ret;

    while (*link) {
        parent = *link;
        cur_group = rb_entry(parent, struct mcast_group, node);

        ret = memcmp(group->rec.mgid.raw, cur_group->rec.mgid.raw,
                 sizeof group->rec.mgid);
        if (ret < 0)
            link = &(*link)->rb_left;
        else if (ret > 0)
            link = &(*link)->rb_right;
        else if (allow_duplicates)
            link = &(*link)->rb_left;
        else
            return cur_group;
    }
    rb_link_node(&group->node, parent, link);
    rb_insert_color(&group->node, &port->table);
    return NULL;
}

static void deref_port(struct mcast_port *port)
{
    if (atomic_dec_and_test(&port->refcount))
        complete(&port->comp);
}

static void release_group(struct mcast_group *group)
{
    struct mcast_port *port = group->port;
    unsigned long flags;

    spin_lock_irqsave(&port->lock, flags);
    if (atomic_dec_and_test(&group->refcount)) {
        rb_erase(&group->node, &port->table);
        spin_unlock_irqrestore(&port->lock, flags);
        kfree(group);
        deref_port(port);
    } else
        spin_unlock_irqrestore(&port->lock, flags);
}

static void deref_member(struct mcast_member *member)
{
    if (atomic_dec_and_test(&member->refcount))
        complete(&member->comp);
}

static void queue_join(struct mcast_member *member)
{
    struct mcast_group *group = member->group;
    unsigned long flags;

    spin_lock_irqsave(&group->lock, flags);
    list_add_tail(&member->list, &group->pending_list);
    if (group->state == MCAST_IDLE) {
        group->state = MCAST_BUSY;
        atomic_inc(&group->refcount);
        queue_work(mcast_wq, &group->work);
    }
    spin_unlock_irqrestore(&group->lock, flags);
}

/*
 * A multicast group has three types of members: full member, non member, and
 * send only member.  We need to keep track of the number of members of each
 * type based on their join state.  Adjust the number of members the belong to
 * the specified join states.
 */
static void adjust_membership(struct mcast_group *group, u8 join_state, int inc)
{
    int i;

    for (i = 0; i < 3; i++, join_state >>= 1)
        if (join_state & 0x1)
            group->members[i] += inc;
}

/*
 * If a multicast group has zero members left for a particular join state, but
 * the group is still a member with the SA, we need to leave that join state.
 * Determine which join states we still belong to, but that do not have any
 * active members.
 */
static u8 get_leave_state(struct mcast_group *group)
{
    u8 leave_state = 0;
    int i;

    for (i = 0; i < 3; i++)
        if (!group->members[i])
            leave_state |= (0x1 << i);

    return leave_state & group->rec.join_state;
}

static int check_selector(ib_sa_comp_mask comp_mask,
              ib_sa_comp_mask selector_mask,
              ib_sa_comp_mask value_mask,
              u8 selector, u8 src_value, u8 dst_value)
{
    int err;

    if (!(comp_mask & selector_mask) || !(comp_mask & value_mask))
        return 0;

    switch (selector) {
    case IB_SA_GT:
        err = (src_value <= dst_value);
        break;
    case IB_SA_LT:
        err = (src_value >= dst_value);
        break;
    case IB_SA_EQ:
        err = (src_value != dst_value);
        break;
    default:
        err = 0;
        break;
    }

    return err;
}

static int cmp_rec(struct ib_sa_mcmember_rec *src,
           struct ib_sa_mcmember_rec *dst, ib_sa_comp_mask comp_mask)
{
    /* MGID must already match */

    if (comp_mask & IB_SA_MCMEMBER_REC_PORT_GID &&
        memcmp(&src->port_gid, &dst->port_gid, sizeof src->port_gid))
        return -EINVAL;
    if (comp_mask & IB_SA_MCMEMBER_REC_QKEY && src->qkey != dst->qkey)
        return -EINVAL;
    if (comp_mask & IB_SA_MCMEMBER_REC_MLID && src->mlid != dst->mlid)
        return -EINVAL;
    if (check_selector(comp_mask, IB_SA_MCMEMBER_REC_MTU_SELECTOR,
               IB_SA_MCMEMBER_REC_MTU, dst->mtu_selector,
               src->mtu, dst->mtu))
        return -EINVAL;
    if (comp_mask & IB_SA_MCMEMBER_REC_TRAFFIC_CLASS &&
        src->traffic_class != dst->traffic_class)
        return -EINVAL;
    if (comp_mask & IB_SA_MCMEMBER_REC_PKEY && src->pkey != dst->pkey)
        return -EINVAL;
    if (check_selector(comp_mask, IB_SA_MCMEMBER_REC_RATE_SELECTOR,
               IB_SA_MCMEMBER_REC_RATE, dst->rate_selector,
               src->rate, dst->rate))
        return -EINVAL;
    if (check_selector(comp_mask,
               IB_SA_MCMEMBER_REC_PACKET_LIFE_TIME_SELECTOR,
               IB_SA_MCMEMBER_REC_PACKET_LIFE_TIME,
               dst->packet_life_time_selector,
               src->packet_life_time, dst->packet_life_time))
        return -EINVAL;
    if (comp_mask & IB_SA_MCMEMBER_REC_SL && src->sl != dst->sl)
        return -EINVAL;
    if (comp_mask & IB_SA_MCMEMBER_REC_FLOW_LABEL &&
        src->flow_label != dst->flow_label)
        return -EINVAL;
    if (comp_mask & IB_SA_MCMEMBER_REC_HOP_LIMIT &&
        src->hop_limit != dst->hop_limit)
        return -EINVAL;
    if (comp_mask & IB_SA_MCMEMBER_REC_SCOPE && src->scope != dst->scope)
        return -EINVAL;

    /* join_state checked separately, proxy_join ignored */

    return 0;
}

static int send_join(struct mcast_group *group, struct mcast_member *member)
{
    struct mcast_port *port = group->port;
    int ret;

    group->last_join = member;
    ret = ib_sa_mcmember_rec_query(&sa_client, port->dev->device,
                       port->port_num, IB_MGMT_METHOD_SET,
                       &member->multicast.rec,
                       member->multicast.comp_mask,
                       3000, GFP_KERNEL, join_handler, group,
                       &group->query);
    if (ret >= 0) {
        group->query_id = ret;
        ret = 0;
    }
    return ret;
}

static int send_leave(struct mcast_group *group, u8 leave_state)
{
    struct mcast_port *port = group->port;
    struct ib_sa_mcmember_rec rec;
    int ret;

    rec = group->rec;
    rec.join_state = leave_state;
    group->leave_state = leave_state;

    ret = ib_sa_mcmember_rec_query(&sa_client, port->dev->device,
                       port->port_num, IB_SA_METHOD_DELETE, &rec,
                       IB_SA_MCMEMBER_REC_MGID     |
                       IB_SA_MCMEMBER_REC_PORT_GID |
                       IB_SA_MCMEMBER_REC_JOIN_STATE,
                       3000, GFP_KERNEL, leave_handler,
                       group, &group->query);
    if (ret >= 0) {
        group->query_id = ret;
        ret = 0;
    }
    return ret;
}

static void join_group(struct mcast_group *group, struct mcast_member *member,
               u8 join_state)
{
    member->state = MCAST_MEMBER;
    adjust_membership(group, join_state, 1);
    group->rec.join_state |= join_state;
    member->multicast.rec = group->rec;
    member->multicast.rec.join_state = join_state;
    list_move(&member->list, &group->active_list);
}

static int fail_join(struct mcast_group *group, struct mcast_member *member,
             int status)
{
    spin_lock_irq(&group->lock);
    list_del_init(&member->list);
    spin_unlock_irq(&group->lock);
    return member->multicast.callback(status, &member->multicast);
}

static void process_group_error(struct mcast_group *group)
{
    struct mcast_member *member;
    int ret = 0;
    u16 pkey_index;

    if (group->state == MCAST_PKEY_EVENT)
        ret = ib_find_pkey(group->port->dev->device,
                   group->port->port_num,
                   be16_to_cpu(group->rec.pkey), &pkey_index);

    spin_lock_irq(&group->lock);
    if (group->state == MCAST_PKEY_EVENT && !ret &&
        group->pkey_index == pkey_index)
        goto out;

    while (!list_empty(&group->active_list)) {
        member = list_entry(group->active_list.next,
                    struct mcast_member, list);
        atomic_inc(&member->refcount);
        list_del_init(&member->list);
        adjust_membership(group, member->multicast.rec.join_state, -1);
        member->state = MCAST_ERROR;
        spin_unlock_irq(&group->lock);

        ret = member->multicast.callback(-ENETRESET,
                         &member->multicast);
        deref_member(member);
        if (ret)
            ib_sa_free_multicast(&member->multicast);
        spin_lock_irq(&group->lock);
    }

    group->rec.join_state = 0;
out:
    group->state = MCAST_BUSY;
    spin_unlock_irq(&group->lock);
}

static void mcast_work_handler(struct work_struct *work)
{
    struct mcast_group *group;
    struct mcast_member *member;
    struct ib_sa_multicast *multicast;
    int status, ret;
    u8 join_state;

    group = container_of(work, typeof(*group), work);
retest:
    spin_lock_irq(&group->lock);
    while (!list_empty(&group->pending_list) ||
           (group->state != MCAST_BUSY)) {

        if (group->state != MCAST_BUSY) {
            spin_unlock_irq(&group->lock);
            process_group_error(group);
            goto retest;
        }

        member = list_entry(group->pending_list.next,
                    struct mcast_member, list);
        multicast = &member->multicast;
        join_state = multicast->rec.join_state;
        atomic_inc(&member->refcount);

        if (join_state == (group->rec.join_state & join_state)) {
            status = cmp_rec(&group->rec, &multicast->rec,
                     multicast->comp_mask);
            if (!status)
                join_group(group, member, join_state);
            else
                list_del_init(&member->list);
            spin_unlock_irq(&group->lock);
            ret = multicast->callback(status, multicast);
        } else {
            spin_unlock_irq(&group->lock);
            status = send_join(group, member);
            if (!status) {
                deref_member(member);
                return;
            }
            ret = fail_join(group, member, status);
        }

        deref_member(member);
        if (ret)
            ib_sa_free_multicast(&member->multicast);
        spin_lock_irq(&group->lock);
    }

    join_state = get_leave_state(group);
    if (join_state) {
        group->rec.join_state &= ~join_state;
        spin_unlock_irq(&group->lock);
        if (send_leave(group, join_state))
            goto retest;
    } else {
        group->state = MCAST_IDLE;
        spin_unlock_irq(&group->lock);
        release_group(group);
    }
}

/*
 * Fail a join request if it is still active - at the head of the pending queue.
 */
static void process_join_error(struct mcast_group *group, int status)
{
    struct mcast_member *member;
    int ret;

    spin_lock_irq(&group->lock);
    member = list_entry(group->pending_list.next,
                struct mcast_member, list);
    if (group->last_join == member) {
        atomic_inc(&member->refcount);
        list_del_init(&member->list);
        spin_unlock_irq(&group->lock);
        ret = member->multicast.callback(status, &member->multicast);
        deref_member(member);
        if (ret)
            ib_sa_free_multicast(&member->multicast);
    } else
        spin_unlock_irq(&group->lock);
}

static void join_handler(int status, struct ib_sa_mcmember_rec *rec,
             void *context)
{
    struct mcast_group *group = context;
    u16 pkey_index = MCAST_INVALID_PKEY_INDEX;

    if (status)
        process_join_error(group, status);
    else {
        ib_find_pkey(group->port->dev->device, group->port->port_num,
                 be16_to_cpu(rec->pkey), &pkey_index);

        spin_lock_irq(&group->port->lock);
        group->rec = *rec;
        if (group->state == MCAST_BUSY &&
            group->pkey_index == MCAST_INVALID_PKEY_INDEX)
            group->pkey_index = pkey_index;
        if (!memcmp(&mgid0, &group->rec.mgid, sizeof mgid0)) {
            rb_erase(&group->node, &group->port->table);
            mcast_insert(group->port, group, 1);
        }
        spin_unlock_irq(&group->port->lock);
    }
    mcast_work_handler(&group->work);
}

static void leave_handler(int status, struct ib_sa_mcmember_rec *rec,
              void *context)
{
    struct mcast_group *group = context;

    if (status && group->retries > 0 &&
        !send_leave(group, group->leave_state))
        group->retries--;
    else
        mcast_work_handler(&group->work);
}

static struct mcast_group *acquire_group(struct mcast_port *port,
                     union ib_gid *mgid, gfp_t gfp_mask)
{
    struct mcast_group *group, *cur_group;
    unsigned long flags;
    int is_mgid0;

    is_mgid0 = !memcmp(&mgid0, mgid, sizeof mgid0);
    if (!is_mgid0) {
        spin_lock_irqsave(&port->lock, flags);
        group = mcast_find(port, mgid);
        if (group)
            goto found;
        spin_unlock_irqrestore(&port->lock, flags);
    }

    group = kzalloc(sizeof *group, gfp_mask);
    if (!group)
        return NULL;

    group->retries = 3;
    group->port = port;
    group->rec.mgid = *mgid;
    group->pkey_index = MCAST_INVALID_PKEY_INDEX;
    INIT_LIST_HEAD(&group->pending_list);
    INIT_LIST_HEAD(&group->active_list);
    INIT_WORK(&group->work, mcast_work_handler);
    spin_lock_init(&group->lock);

    spin_lock_irqsave(&port->lock, flags);
    cur_group = mcast_insert(port, group, is_mgid0);
    if (cur_group) {
        kfree(group);
        group = cur_group;
    } else
        atomic_inc(&port->refcount);
found:
    atomic_inc(&group->refcount);
    spin_unlock_irqrestore(&port->lock, flags);
    return group;
}

/*
 * We serialize all join requests to a single group to make our lives much
 * easier.  Otherwise, two users could try to join the same group
 * simultaneously, with different configurations, one could leave while the
 * join is in progress, etc., which makes locking around error recovery
 * difficult.
 */
struct ib_sa_multicast *
ib_sa_join_multicast(struct ib_sa_client *client,
             struct ib_device *device, u8 port_num,
             struct ib_sa_mcmember_rec *rec,
             ib_sa_comp_mask comp_mask, gfp_t gfp_mask,
             int (*callback)(int status,
                     struct ib_sa_multicast *multicast),
             void *context)
{
    struct mcast_device *dev;
    struct mcast_member *member;
    struct ib_sa_multicast *multicast;
    int ret;

    dev = ib_get_client_data(device, &mcast_client);
    if (!dev)
        return ERR_PTR(-ENODEV);

    member = kmalloc(sizeof *member, gfp_mask);
    if (!member)
        return ERR_PTR(-ENOMEM);

    ib_sa_client_get(client);
    member->client = client;
    member->multicast.rec = *rec;
    member->multicast.comp_mask = comp_mask;
    member->multicast.callback = callback;
    member->multicast.context = context;
    init_completion(&member->comp);
    atomic_set(&member->refcount, 1);
    member->state = MCAST_JOINING;

    member->group = acquire_group(&dev->port[port_num - dev->start_port],
                      &rec->mgid, gfp_mask);
    if (!member->group) {
        ret = -ENOMEM;
        goto err;
    }

    /*
     * The user will get the multicast structure in their callback.  They
     * could then free the multicast structure before we can return from
     * this routine.  So we save the pointer to return before queuing
     * any callback.
     */
    multicast = &member->multicast;
    queue_join(member);
    return multicast;

err:
    ib_sa_client_put(client);
    kfree(member);
    return ERR_PTR(ret);
}
EXPORT_SYMBOL(ib_sa_join_multicast);

void ib_sa_free_multicast(struct ib_sa_multicast *multicast)
{
    struct mcast_member *member;
    struct mcast_group *group;

    member = container_of(multicast, struct mcast_member, multicast);
    group = member->group;

    spin_lock_irq(&group->lock);
    if (member->state == MCAST_MEMBER)
        adjust_membership(group, multicast->rec.join_state, -1);

    list_del_init(&member->list);

    if (group->state == MCAST_IDLE) {
        group->state = MCAST_BUSY;
        spin_unlock_irq(&group->lock);
        /* Continue to hold reference on group until callback */
        queue_work(mcast_wq, &group->work);
    } else {
        spin_unlock_irq(&group->lock);
        release_group(group);
    }

    deref_member(member);
    wait_for_completion(&member->comp);
    ib_sa_client_put(member->client);
    kfree(member);
}
EXPORT_SYMBOL(ib_sa_free_multicast);

int ib_sa_get_mcmember_rec(struct ib_device *device, u8 port_num,
               union ib_gid *mgid, struct ib_sa_mcmember_rec *rec)
{
    struct mcast_device *dev;
    struct mcast_port *port;
    struct mcast_group *group;
    unsigned long flags;
    int ret = 0;

    dev = ib_get_client_data(device, &mcast_client);
    if (!dev)
        return -ENODEV;

    port = &dev->port[port_num - dev->start_port];
    spin_lock_irqsave(&port->lock, flags);
    group = mcast_find(port, mgid);
    if (group)
        *rec = group->rec;
    else
        ret = -EADDRNOTAVAIL;
    spin_unlock_irqrestore(&port->lock, flags);

    return ret;
}
EXPORT_SYMBOL(ib_sa_get_mcmember_rec);

int ib_init_ah_from_mcmember(struct ib_device *device, u8 port_num,
                 struct ib_sa_mcmember_rec *rec,
                 struct ib_ah_attr *ah_attr)
{
    int ret;
    u16 gid_index;
    u8 p;

    ret = ib_find_cached_gid(device, &rec->port_gid, &p, &gid_index);
    if (ret)
        return ret;

    memset(ah_attr, 0, sizeof *ah_attr);
    ah_attr->dlid = be16_to_cpu(rec->mlid);
    ah_attr->sl = rec->sl;
    ah_attr->port_num = port_num;
    ah_attr->static_rate = rec->rate;

    ah_attr->ah_flags = IB_AH_GRH;
    ah_attr->grh.dgid = rec->mgid;

    ah_attr->grh.sgid_index = (u8) gid_index;
    ah_attr->grh.flow_label = be32_to_cpu(rec->flow_label);
    ah_attr->grh.hop_limit = rec->hop_limit;
    ah_attr->grh.traffic_class = rec->traffic_class;

    return 0;
}
EXPORT_SYMBOL(ib_init_ah_from_mcmember);

static void mcast_groups_event(struct mcast_port *port,
                   enum mcast_group_state state)
{
    struct mcast_group *group;
    struct rb_node *node;
    unsigned long flags;

    spin_lock_irqsave(&port->lock, flags);
    for (node = rb_first(&port->table); node; node = rb_next(node)) {
        group = rb_entry(node, struct mcast_group, node);
        spin_lock(&group->lock);
        if (group->state == MCAST_IDLE) {
            atomic_inc(&group->refcount);
            queue_work(mcast_wq, &group->work);
        }
        if (group->state != MCAST_GROUP_ERROR)
            group->state = state;
        spin_unlock(&group->lock);
    }
    spin_unlock_irqrestore(&port->lock, flags);
}

static void mcast_event_handler(struct ib_event_handler *handler,
                struct ib_event *event)
{
    struct mcast_device *dev;
    int index;

    dev = container_of(handler, struct mcast_device, event_handler);
    if (rdma_port_get_link_layer(dev->device, event->element.port_num) !=
        IB_LINK_LAYER_INFINIBAND)
        return;

    index = event->element.port_num - dev->start_port;

    switch (event->event) {
    case IB_EVENT_PORT_ERR:
    case IB_EVENT_LID_CHANGE:
    case IB_EVENT_SM_CHANGE:
    case IB_EVENT_CLIENT_REREGISTER:
        mcast_groups_event(&dev->port[index], MCAST_GROUP_ERROR);
        break;
    case IB_EVENT_PKEY_CHANGE:
        mcast_groups_event(&dev->port[index], MCAST_PKEY_EVENT);
        break;
    default:
        break;
    }
}

static void mcast_add_one(struct ib_device *device)
{
    struct mcast_device *dev;
    struct mcast_port *port;
    int i;
    int count = 0;

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

    dev = kmalloc(sizeof *dev + device->phys_port_cnt * sizeof *port,
              GFP_KERNEL);
    if (!dev)
        return;

    if (device->node_type == RDMA_NODE_IB_SWITCH)
        dev->start_port = dev->end_port = 0;
    else {
        dev->start_port = 1;
        dev->end_port = device->phys_port_cnt;
    }

    for (i = 0; i <= dev->end_port - dev->start_port; i++) {
        if (rdma_port_get_link_layer(device, dev->start_port + i) !=
            IB_LINK_LAYER_INFINIBAND)
            continue;
        port = &dev->port[i];
        port->dev = dev;
        port->port_num = dev->start_port + i;
        spin_lock_init(&port->lock);
        port->table = RB_ROOT;
        init_completion(&port->comp);
        atomic_set(&port->refcount, 1);
        ++count;
    }

    if (!count) {
        kfree(dev);
        return;
    }

    dev->device = device;
    ib_set_client_data(device, &mcast_client, dev);

    INIT_IB_EVENT_HANDLER(&dev->event_handler, device, mcast_event_handler);
    ib_register_event_handler(&dev->event_handler);
}

static void mcast_remove_one(struct ib_device *device)
{
    struct mcast_device *dev;
    struct mcast_port *port;
    int i;

    dev = ib_get_client_data(device, &mcast_client);
    if (!dev)
        return;

    ib_unregister_event_handler(&dev->event_handler);
    flush_workqueue(mcast_wq);

    for (i = 0; i <= dev->end_port - dev->start_port; i++) {
        if (rdma_port_get_link_layer(device, dev->start_port + i) ==
            IB_LINK_LAYER_INFINIBAND) {
            port = &dev->port[i];
            deref_port(port);
            wait_for_completion(&port->comp);
        }
    }

    kfree(dev);
}

int mcast_init(void)
{
    int ret;

    mcast_wq = create_singlethread_workqueue("ib_mcast");
    if (!mcast_wq)
        return -ENOMEM;

    ib_sa_register_client(&sa_client);

    ret = ib_register_client(&mcast_client);
    if (ret)
        goto err;
    return 0;

err:
    ib_sa_unregister_client(&sa_client);
    destroy_workqueue(mcast_wq);
    return ret;
}

void mcast_cleanup(void)
{
    ib_unregister_client(&mcast_client);
    ib_sa_unregister_client(&sa_client);
    destroy_workqueue(mcast_wq);
}