/*
 * 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 int mcast_add_one(struct ib_device *device);
static void mcast_remove_one(struct ib_device *device, void *client_data);

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;
        refcount_t              refcount;
        struct completion       comp;
        u32                     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[];
};

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[NUM_JOIN_MEMBERSHIP_TYPES];
        atomic_t                refcount;
        enum mcast_group_state  state;
        struct ib_sa_query      *query;
        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;
        refcount_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 (refcount_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 (refcount_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 four types of members: full member, non member,
 * sendonly non member and sendonly full 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 < NUM_JOIN_MEMBERSHIP_TYPES; 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 < NUM_JOIN_MEMBERSHIP_TYPES; 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);
        return (ret > 0) ? 0 : 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);
        return (ret > 0) ? 0 : 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);
                refcount_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;
                refcount_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) {
                refcount_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 {
                int mgids_changed, is_mgid0;

                if (ib_find_pkey(group->port->dev->device,
                                 group->port->port_num, be16_to_cpu(rec->pkey),
                                 &pkey_index))
                        pkey_index = MCAST_INVALID_PKEY_INDEX;

                spin_lock_irq(&group->port->lock);
                if (group->state == MCAST_BUSY &&
                    group->pkey_index == MCAST_INVALID_PKEY_INDEX)
                        group->pkey_index = pkey_index;
                mgids_changed = memcmp(&rec->mgid, &group->rec.mgid,
                                       sizeof(group->rec.mgid));
                group->rec = *rec;
                if (mgids_changed) {
                        rb_erase(&group->node, &group->port->table);
                        is_mgid0 = !memcmp(&mgid0, &group->rec.mgid,
                                           sizeof(mgid0));
                        mcast_insert(group->port, group, is_mgid0);
                }
                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_obj(*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
                refcount_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, u32 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_obj(*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);
        refcount_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, u32 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);

/**
 * ib_init_ah_from_mcmember - Initialize AH attribute from multicast
 * member record and gid of the device.
 * @device:     RDMA device
 * @port_num:   Port of the rdma device to consider
 * @rec:        Multicast member record to use
 * @ndev:       Optional netdevice, applicable only for RoCE
 * @gid_type:   GID type to consider
 * @ah_attr:    AH attribute to fillup on successful completion
 *
 * ib_init_ah_from_mcmember() initializes AH attribute based on multicast
 * member record and other device properties. On success the caller is
 * responsible to call rdma_destroy_ah_attr on the ah_attr. Returns 0 on
 * success or appropriate error code.
 *
 */
int ib_init_ah_from_mcmember(struct ib_device *device, u32 port_num,
                             struct ib_sa_mcmember_rec *rec,
                             struct net_device *ndev,
                             enum ib_gid_type gid_type,
                             struct rdma_ah_attr *ah_attr)
{
        const struct ib_gid_attr *sgid_attr;

        /* GID table is not based on the netdevice for IB link layer,
         * so ignore ndev during search.
         */
        if (rdma_protocol_ib(device, port_num))
                ndev = NULL;
        else if (!rdma_protocol_roce(device, port_num))
                return -EINVAL;

        sgid_attr = rdma_find_gid_by_port(device, &rec->port_gid,
                                          gid_type, port_num, ndev);
        if (IS_ERR(sgid_attr))
                return PTR_ERR(sgid_attr);

        memset(ah_attr, 0, sizeof(*ah_attr));
        ah_attr->type = rdma_ah_find_type(device, port_num);

        rdma_ah_set_dlid(ah_attr, be16_to_cpu(rec->mlid));
        rdma_ah_set_sl(ah_attr, rec->sl);
        rdma_ah_set_port_num(ah_attr, port_num);
        rdma_ah_set_static_rate(ah_attr, rec->rate);
        rdma_move_grh_sgid_attr(ah_attr, &rec->mgid,
                                be32_to_cpu(rec->flow_label),
                                rec->hop_limit, rec->traffic_class,
                                sgid_attr);
        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_cap_ib_mcast(dev->device, event->element.port_num))
                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_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 int mcast_add_one(struct ib_device *device)
{
        struct mcast_device *dev;
        struct mcast_port *port;
        int i;
        int count = 0;

        dev = kmalloc_flex(*dev, port, device->phys_port_cnt);
        if (!dev)
                return -ENOMEM;

        dev->start_port = rdma_start_port(device);
        dev->end_port = rdma_end_port(device);

        for (i = 0; i <= dev->end_port - dev->start_port; i++) {
                if (!rdma_cap_ib_mcast(device, dev->start_port + i))
                        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);
                refcount_set(&port->refcount, 1);
                ++count;
        }

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

        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);
        return 0;
}

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

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

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

        kfree(dev);
}

int mcast_init(void)
{
        int ret;

        mcast_wq = alloc_ordered_workqueue("ib_mcast", WQ_MEM_RECLAIM);
        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);
}