mcg.c

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/*
 * Copyright (c) 2012 Mellanox Technologies. 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 <rdma/ib_mad.h>
#include <rdma/ib_smi.h>
#include <rdma/ib_cache.h>
#include <rdma/ib_sa.h>

#include <linux/mlx4/cmd.h>
#include <linux/rbtree.h>
#include <linux/delay.h>

#include "mlx4_ib.h"

#define MAX_VFS     80
#define MAX_PEND_REQS_PER_FUNC 4
#define MAD_TIMEOUT_MS  2000

#define mcg_warn(fmt, arg...)   pr_warn("MCG WARNING: " fmt, ##arg)
#define mcg_error(fmt, arg...)  pr_err(fmt, ##arg)
#define mcg_warn_group(group, format, arg...) \
    pr_warn("%s-%d: %16s (port %d): WARNING: " format, __func__, __LINE__,\
    (group)->name, group->demux->port, ## arg)

#define mcg_error_group(group, format, arg...) \
    pr_err("  %16s: " format, (group)->name, ## arg)


static union ib_gid mgid0;

static struct workqueue_struct *clean_wq;

enum mcast_state {
    MCAST_NOT_MEMBER = 0,
    MCAST_MEMBER,
};

enum mcast_group_state {
    MCAST_IDLE,
    MCAST_JOIN_SENT,
    MCAST_LEAVE_SENT,
    MCAST_RESP_READY
};

struct mcast_member {
    enum mcast_state state;
    uint8_t         join_state;
    int         num_pend_reqs;
    struct list_head    pending;
};

struct ib_sa_mcmember_data {
    union ib_gid    mgid;
    union ib_gid    port_gid;
    __be32      qkey;
    __be16      mlid;
    u8      mtusel_mtu;
    u8      tclass;
    __be16      pkey;
    u8      ratesel_rate;
    u8      lifetmsel_lifetm;
    __be32      sl_flowlabel_hoplimit;
    u8      scope_join_state;
    u8      proxy_join;
    u8      reserved[2];
};

struct mcast_group {
    struct ib_sa_mcmember_data rec;
    struct rb_node      node;
    struct list_head    mgid0_list;
    struct mlx4_ib_demux_ctx *demux;
    struct mcast_member func[MAX_VFS];
    struct mutex        lock;
    struct work_struct  work;
    struct list_head    pending_list;
    int         members[3];
    enum mcast_group_state  state;
    enum mcast_group_state  prev_state;
    struct ib_sa_mad    response_sa_mad;
    __be64          last_req_tid;

    char            name[33]; /* MGID string */
    struct device_attribute dentry;

    /* refcount is the reference count for the following:
       1. Each queued request
       2. Each invocation of the worker thread
       3. Membership of the port at the SA
    */
    atomic_t        refcount;

    /* delayed work to clean pending SM request */
    struct delayed_work timeout_work;
    struct list_head    cleanup_list;
};

struct mcast_req {
    int         func;
    struct ib_sa_mad    sa_mad;
    struct list_head    group_list;
    struct list_head    func_list;
    struct mcast_group  *group;
    int         clean;
};


#define safe_atomic_dec(ref) \
    do {\
        if (atomic_dec_and_test(ref)) \
            mcg_warn_group(group, "did not expect to reach zero\n"); \
    } while (0)

static const char *get_state_string(enum mcast_group_state state)
{
    switch (state) {
    case MCAST_IDLE:
        return "MCAST_IDLE";
    case MCAST_JOIN_SENT:
        return "MCAST_JOIN_SENT";
    case MCAST_LEAVE_SENT:
        return "MCAST_LEAVE_SENT";
    case MCAST_RESP_READY:
        return "MCAST_RESP_READY";
    }
    return "Invalid State";
}

static struct mcast_group *mcast_find(struct mlx4_ib_demux_ctx *ctx,
                      union ib_gid *mgid)
{
    struct rb_node *node = ctx->mcg_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 mlx4_ib_demux_ctx *ctx,
                    struct mcast_group *group)
{
    struct rb_node **link = &ctx->mcg_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
            return cur_group;
    }
    rb_link_node(&group->node, parent, link);
    rb_insert_color(&group->node, &ctx->mcg_table);
    return NULL;
}

static int send_mad_to_wire(struct mlx4_ib_demux_ctx *ctx, struct ib_mad *mad)
{
    struct mlx4_ib_dev *dev = ctx->dev;
    struct ib_ah_attr   ah_attr;

    spin_lock(&dev->sm_lock);
    if (!dev->sm_ah[ctx->port - 1]) {
        /* port is not yet Active, sm_ah not ready */
        spin_unlock(&dev->sm_lock);
        return -EAGAIN;
    }
    mlx4_ib_query_ah(dev->sm_ah[ctx->port - 1], &ah_attr);
    spin_unlock(&dev->sm_lock);
    return mlx4_ib_send_to_wire(dev, mlx4_master_func_num(dev->dev), ctx->port,
                    IB_QPT_GSI, 0, 1, IB_QP1_QKEY, &ah_attr, mad);
}

static int send_mad_to_slave(int slave, struct mlx4_ib_demux_ctx *ctx,
                 struct ib_mad *mad)
{
    struct mlx4_ib_dev *dev = ctx->dev;
    struct ib_mad_agent *agent = dev->send_agent[ctx->port - 1][1];
    struct ib_wc wc;
    struct ib_ah_attr ah_attr;

    /* Our agent might not yet be registered when mads start to arrive */
    if (!agent)
        return -EAGAIN;

    ib_query_ah(dev->sm_ah[ctx->port - 1], &ah_attr);

    if (ib_find_cached_pkey(&dev->ib_dev, ctx->port, IB_DEFAULT_PKEY_FULL, &wc.pkey_index))
        return -EINVAL;
    wc.sl = 0;
    wc.dlid_path_bits = 0;
    wc.port_num = ctx->port;
    wc.slid = ah_attr.dlid;  /* opensm lid */
    wc.src_qp = 1;
    return mlx4_ib_send_to_slave(dev, slave, ctx->port, IB_QPT_GSI, &wc, NULL, mad);
}

static int send_join_to_wire(struct mcast_group *group, struct ib_sa_mad *sa_mad)
{
    struct ib_sa_mad mad;
    struct ib_sa_mcmember_data *sa_mad_data = (struct ib_sa_mcmember_data *)&mad.data;
    int ret;

    /* we rely on a mad request as arrived from a VF */
    memcpy(&mad, sa_mad, sizeof mad);

    /* fix port GID to be the real one (slave 0) */
    sa_mad_data->port_gid.global.interface_id = group->demux->guid_cache[0];

    /* assign our own TID */
    mad.mad_hdr.tid = mlx4_ib_get_new_demux_tid(group->demux);
    group->last_req_tid = mad.mad_hdr.tid; /* keep it for later validation */

    ret = send_mad_to_wire(group->demux, (struct ib_mad *)&mad);
    /* set timeout handler */
    if (!ret) {
        /* calls mlx4_ib_mcg_timeout_handler */
        queue_delayed_work(group->demux->mcg_wq, &group->timeout_work,
                msecs_to_jiffies(MAD_TIMEOUT_MS));
    }

    return ret;
}

static int send_leave_to_wire(struct mcast_group *group, u8 join_state)
{
    struct ib_sa_mad mad;
    struct ib_sa_mcmember_data *sa_data = (struct ib_sa_mcmember_data *)&mad.data;
    int ret;

    memset(&mad, 0, sizeof mad);
    mad.mad_hdr.base_version = 1;
    mad.mad_hdr.mgmt_class = IB_MGMT_CLASS_SUBN_ADM;
    mad.mad_hdr.class_version = 2;
    mad.mad_hdr.method = IB_SA_METHOD_DELETE;
    mad.mad_hdr.status = cpu_to_be16(0);
    mad.mad_hdr.class_specific = cpu_to_be16(0);
    mad.mad_hdr.tid = mlx4_ib_get_new_demux_tid(group->demux);
    group->last_req_tid = mad.mad_hdr.tid; /* keep it for later validation */
    mad.mad_hdr.attr_id = cpu_to_be16(IB_SA_ATTR_MC_MEMBER_REC);
    mad.mad_hdr.attr_mod = cpu_to_be32(0);
    mad.sa_hdr.sm_key = 0x0;
    mad.sa_hdr.attr_offset = cpu_to_be16(7);
    mad.sa_hdr.comp_mask = IB_SA_MCMEMBER_REC_MGID |
        IB_SA_MCMEMBER_REC_PORT_GID | IB_SA_MCMEMBER_REC_JOIN_STATE;

    *sa_data = group->rec;
    sa_data->scope_join_state = join_state;

    ret = send_mad_to_wire(group->demux, (struct ib_mad *)&mad);
    if (ret)
        group->state = MCAST_IDLE;

    /* set timeout handler */
    if (!ret) {
        /* calls mlx4_ib_mcg_timeout_handler */
        queue_delayed_work(group->demux->mcg_wq, &group->timeout_work,
                msecs_to_jiffies(MAD_TIMEOUT_MS));
    }

    return ret;
}

static int send_reply_to_slave(int slave, struct mcast_group *group,
        struct ib_sa_mad *req_sa_mad, u16 status)
{
    struct ib_sa_mad mad;
    struct ib_sa_mcmember_data *sa_data = (struct ib_sa_mcmember_data *)&mad.data;
    struct ib_sa_mcmember_data *req_sa_data = (struct ib_sa_mcmember_data *)&req_sa_mad->data;
    int ret;

    memset(&mad, 0, sizeof mad);
    mad.mad_hdr.base_version = 1;
    mad.mad_hdr.mgmt_class = IB_MGMT_CLASS_SUBN_ADM;
    mad.mad_hdr.class_version = 2;
    mad.mad_hdr.method = IB_MGMT_METHOD_GET_RESP;
    mad.mad_hdr.status = cpu_to_be16(status);
    mad.mad_hdr.class_specific = cpu_to_be16(0);
    mad.mad_hdr.tid = req_sa_mad->mad_hdr.tid;
    *(u8 *)&mad.mad_hdr.tid = 0; /* resetting tid to 0 */
    mad.mad_hdr.attr_id = cpu_to_be16(IB_SA_ATTR_MC_MEMBER_REC);
    mad.mad_hdr.attr_mod = cpu_to_be32(0);
    mad.sa_hdr.sm_key = req_sa_mad->sa_hdr.sm_key;
    mad.sa_hdr.attr_offset = cpu_to_be16(7);
    mad.sa_hdr.comp_mask = 0; /* ignored on responses, see IBTA spec */

    *sa_data = group->rec;

    /* reconstruct VF's requested join_state and port_gid */
    sa_data->scope_join_state &= 0xf0;
    sa_data->scope_join_state |= (group->func[slave].join_state & 0x0f);
    memcpy(&sa_data->port_gid, &req_sa_data->port_gid, sizeof req_sa_data->port_gid);

    ret = send_mad_to_slave(slave, group->demux, (struct ib_mad *)&mad);
    return ret;
}

static int check_selector(ib_sa_comp_mask comp_mask,
              ib_sa_comp_mask selector_mask,
              ib_sa_comp_mask value_mask,
              u8 src_value, u8 dst_value)
{
    int err;
    u8 selector = dst_value >> 6;
    dst_value &= 0x3f;
    src_value &= 0x3f;

    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 u16 cmp_rec(struct ib_sa_mcmember_data *src,
           struct ib_sa_mcmember_data *dst, ib_sa_comp_mask comp_mask)
{
    /* src is group record, dst is request record */
    /* MGID must already match */
    /* Port_GID we always replace to our Port_GID, so it is a match */

#define MAD_STATUS_REQ_INVALID 0x0200
    if (comp_mask & IB_SA_MCMEMBER_REC_QKEY && src->qkey != dst->qkey)
        return MAD_STATUS_REQ_INVALID;
    if (comp_mask & IB_SA_MCMEMBER_REC_MLID && src->mlid != dst->mlid)
        return MAD_STATUS_REQ_INVALID;
    if (check_selector(comp_mask, IB_SA_MCMEMBER_REC_MTU_SELECTOR,
                 IB_SA_MCMEMBER_REC_MTU,
                 src->mtusel_mtu, dst->mtusel_mtu))
        return MAD_STATUS_REQ_INVALID;
    if (comp_mask & IB_SA_MCMEMBER_REC_TRAFFIC_CLASS &&
        src->tclass != dst->tclass)
        return MAD_STATUS_REQ_INVALID;
    if (comp_mask & IB_SA_MCMEMBER_REC_PKEY && src->pkey != dst->pkey)
        return MAD_STATUS_REQ_INVALID;
    if (check_selector(comp_mask, IB_SA_MCMEMBER_REC_RATE_SELECTOR,
                 IB_SA_MCMEMBER_REC_RATE,
                 src->ratesel_rate, dst->ratesel_rate))
        return MAD_STATUS_REQ_INVALID;
    if (check_selector(comp_mask,
                 IB_SA_MCMEMBER_REC_PACKET_LIFE_TIME_SELECTOR,
                 IB_SA_MCMEMBER_REC_PACKET_LIFE_TIME,
                 src->lifetmsel_lifetm, dst->lifetmsel_lifetm))
        return MAD_STATUS_REQ_INVALID;
    if (comp_mask & IB_SA_MCMEMBER_REC_SL &&
            (be32_to_cpu(src->sl_flowlabel_hoplimit) & 0xf0000000) !=
            (be32_to_cpu(dst->sl_flowlabel_hoplimit) & 0xf0000000))
        return MAD_STATUS_REQ_INVALID;
    if (comp_mask & IB_SA_MCMEMBER_REC_FLOW_LABEL &&
            (be32_to_cpu(src->sl_flowlabel_hoplimit) & 0x0fffff00) !=
            (be32_to_cpu(dst->sl_flowlabel_hoplimit) & 0x0fffff00))
        return MAD_STATUS_REQ_INVALID;
    if (comp_mask & IB_SA_MCMEMBER_REC_HOP_LIMIT &&
            (be32_to_cpu(src->sl_flowlabel_hoplimit) & 0x000000ff) !=
            (be32_to_cpu(dst->sl_flowlabel_hoplimit) & 0x000000ff))
        return MAD_STATUS_REQ_INVALID;
    if (comp_mask & IB_SA_MCMEMBER_REC_SCOPE &&
            (src->scope_join_state & 0xf0) !=
            (dst->scope_join_state & 0xf0))
        return MAD_STATUS_REQ_INVALID;

    /* join_state checked separately, proxy_join ignored */

    return 0;
}

/* release group, return 1 if this was last release and group is destroyed
 * timout work is canceled sync */
static int release_group(struct mcast_group *group, int from_timeout_handler)
{
    struct mlx4_ib_demux_ctx *ctx = group->demux;
    int nzgroup;

    mutex_lock(&ctx->mcg_table_lock);
    mutex_lock(&group->lock);
    if (atomic_dec_and_test(&group->refcount)) {
        if (!from_timeout_handler) {
            if (group->state != MCAST_IDLE &&
                !cancel_delayed_work(&group->timeout_work)) {
                atomic_inc(&group->refcount);
                mutex_unlock(&group->lock);
                mutex_unlock(&ctx->mcg_table_lock);
                return 0;
            }
        }

        nzgroup = memcmp(&group->rec.mgid, &mgid0, sizeof mgid0);
        if (nzgroup)
            del_sysfs_port_mcg_attr(ctx->dev, ctx->port, &group->dentry.attr);
        if (!list_empty(&group->pending_list))
            mcg_warn_group(group, "releasing a group with non empty pending list\n");
        if (nzgroup)
            rb_erase(&group->node, &ctx->mcg_table);
        list_del_init(&group->mgid0_list);
        mutex_unlock(&group->lock);
        mutex_unlock(&ctx->mcg_table_lock);
        kfree(group);
        return 1;
    } else {
        mutex_unlock(&group->lock);
        mutex_unlock(&ctx->mcg_table_lock);
    }
    return 0;
}

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;
}

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 |= (1 << i);

    return leave_state & (group->rec.scope_join_state & 7);
}

static int join_group(struct mcast_group *group, int slave, u8 join_mask)
{
    int ret = 0;
    u8 join_state;

    /* remove bits that slave is already member of, and adjust */
    join_state = join_mask & (~group->func[slave].join_state);
    adjust_membership(group, join_state, 1);
    group->func[slave].join_state |= join_state;
    if (group->func[slave].state != MCAST_MEMBER && join_state) {
        group->func[slave].state = MCAST_MEMBER;
        ret = 1;
    }
    return ret;
}

static int leave_group(struct mcast_group *group, int slave, u8 leave_state)
{
    int ret = 0;

    adjust_membership(group, leave_state, -1);
    group->func[slave].join_state &= ~leave_state;
    if (!group->func[slave].join_state) {
        group->func[slave].state = MCAST_NOT_MEMBER;
        ret = 1;
    }
    return ret;
}

static int check_leave(struct mcast_group *group, int slave, u8 leave_mask)
{
    if (group->func[slave].state != MCAST_MEMBER)
        return MAD_STATUS_REQ_INVALID;

    /* make sure we're not deleting unset bits */
    if (~group->func[slave].join_state & leave_mask)
        return MAD_STATUS_REQ_INVALID;

    if (!leave_mask)
        return MAD_STATUS_REQ_INVALID;

    return 0;
}

static void mlx4_ib_mcg_timeout_handler(struct work_struct *work)
{
    struct delayed_work *delay = to_delayed_work(work);
    struct mcast_group *group;
    struct mcast_req *req = NULL;

    group = container_of(delay, typeof(*group), timeout_work);

    mutex_lock(&group->lock);
    if (group->state == MCAST_JOIN_SENT) {
        if (!list_empty(&group->pending_list)) {
            req = list_first_entry(&group->pending_list, struct mcast_req, group_list);
            list_del(&req->group_list);
            list_del(&req->func_list);
            --group->func[req->func].num_pend_reqs;
            mutex_unlock(&group->lock);
            kfree(req);
            if (memcmp(&group->rec.mgid, &mgid0, sizeof mgid0)) {
                if (release_group(group, 1))
                    return;
            } else {
                kfree(group);
                return;
            }
            mutex_lock(&group->lock);
        } else
            mcg_warn_group(group, "DRIVER BUG\n");
    } else if (group->state == MCAST_LEAVE_SENT) {
        if (group->rec.scope_join_state & 7)
            group->rec.scope_join_state &= 0xf8;
        group->state = MCAST_IDLE;
        mutex_unlock(&group->lock);
        if (release_group(group, 1))
            return;
        mutex_lock(&group->lock);
    } else
        mcg_warn_group(group, "invalid state %s\n", get_state_string(group->state));
    group->state = MCAST_IDLE;
    atomic_inc(&group->refcount);
    if (!queue_work(group->demux->mcg_wq, &group->work))
        safe_atomic_dec(&group->refcount);

    mutex_unlock(&group->lock);
}

static int handle_leave_req(struct mcast_group *group, u8 leave_mask,
                struct mcast_req *req)
{
    u16 status;

    if (req->clean)
        leave_mask = group->func[req->func].join_state;

    status = check_leave(group, req->func, leave_mask);
    if (!status)
        leave_group(group, req->func, leave_mask);

    if (!req->clean)
        send_reply_to_slave(req->func, group, &req->sa_mad, status);
    --group->func[req->func].num_pend_reqs;
    list_del(&req->group_list);
    list_del(&req->func_list);
    kfree(req);
    return 1;
}

static int handle_join_req(struct mcast_group *group, u8 join_mask,
               struct mcast_req *req)
{
    u8 group_join_state = group->rec.scope_join_state & 7;
    int ref = 0;
    u16 status;
    struct ib_sa_mcmember_data *sa_data = (struct ib_sa_mcmember_data *)req->sa_mad.data;

    if (join_mask == (group_join_state & join_mask)) {
        /* port's membership need not change */
        status = cmp_rec(&group->rec, sa_data, req->sa_mad.sa_hdr.comp_mask);
        if (!status)
            join_group(group, req->func, join_mask);

        --group->func[req->func].num_pend_reqs;
        send_reply_to_slave(req->func, group, &req->sa_mad, status);
        list_del(&req->group_list);
        list_del(&req->func_list);
        kfree(req);
        ++ref;
    } else {
        /* port's membership needs to be updated */
        group->prev_state = group->state;
        if (send_join_to_wire(group, &req->sa_mad)) {
            --group->func[req->func].num_pend_reqs;
            list_del(&req->group_list);
            list_del(&req->func_list);
            kfree(req);
            ref = 1;
            group->state = group->prev_state;
        } else
            group->state = MCAST_JOIN_SENT;
    }

    return ref;
}

static void mlx4_ib_mcg_work_handler(struct work_struct *work)
{
    struct mcast_group *group;
    struct mcast_req *req = NULL;
    struct ib_sa_mcmember_data *sa_data;
    u8 req_join_state;
    int rc = 1; /* release_count - this is for the scheduled work */
    u16 status;
    u8 method;

    group = container_of(work, typeof(*group), work);

    mutex_lock(&group->lock);

    /* First, let's see if a response from SM is waiting regarding this group.
     * If so, we need to update the group's REC. If this is a bad response, we
     * may need to send a bad response to a VF waiting for it. If VF is waiting
     * and this is a good response, the VF will be answered later in this func. */
    if (group->state == MCAST_RESP_READY) {
        /* cancels mlx4_ib_mcg_timeout_handler */
        cancel_delayed_work(&group->timeout_work);
        status = be16_to_cpu(group->response_sa_mad.mad_hdr.status);
        method = group->response_sa_mad.mad_hdr.method;
        if (group->last_req_tid != group->response_sa_mad.mad_hdr.tid) {
            mcg_warn_group(group, "Got MAD response to existing MGID but wrong TID, dropping. Resp TID=%llx, group TID=%llx\n",
                be64_to_cpu(group->response_sa_mad.mad_hdr.tid),
                be64_to_cpu(group->last_req_tid));
            group->state = group->prev_state;
            goto process_requests;
        }
        if (status) {
            if (!list_empty(&group->pending_list))
                req = list_first_entry(&group->pending_list,
                        struct mcast_req, group_list);
            if ((method == IB_MGMT_METHOD_GET_RESP)) {
                    if (req) {
                        send_reply_to_slave(req->func, group, &req->sa_mad, status);
                        --group->func[req->func].num_pend_reqs;
                        list_del(&req->group_list);
                        list_del(&req->func_list);
                        kfree(req);
                        ++rc;
                    } else
                        mcg_warn_group(group, "no request for failed join\n");
            } else if (method == IB_SA_METHOD_DELETE_RESP && group->demux->flushing)
                ++rc;
        } else {
            u8 resp_join_state;
            u8 cur_join_state;

            resp_join_state = ((struct ib_sa_mcmember_data *)
                        group->response_sa_mad.data)->scope_join_state & 7;
            cur_join_state = group->rec.scope_join_state & 7;

            if (method == IB_MGMT_METHOD_GET_RESP) {
                /* successfull join */
                if (!cur_join_state && resp_join_state)
                    --rc;
            } else if (!resp_join_state)
                    ++rc;
            memcpy(&group->rec, group->response_sa_mad.data, sizeof group->rec);
        }
        group->state = MCAST_IDLE;
    }

process_requests:
    /* We should now go over pending join/leave requests, as long as we are idle. */
    while (!list_empty(&group->pending_list) && group->state == MCAST_IDLE) {
        req = list_first_entry(&group->pending_list, struct mcast_req,
                       group_list);
        sa_data = (struct ib_sa_mcmember_data *)req->sa_mad.data;
        req_join_state = sa_data->scope_join_state & 0x7;

        /* For a leave request, we will immediately answer the VF, and
         * update our internal counters. The actual leave will be sent
         * to SM later, if at all needed. We dequeue the request now. */
        if (req->sa_mad.mad_hdr.method == IB_SA_METHOD_DELETE)
            rc += handle_leave_req(group, req_join_state, req);
        else
            rc += handle_join_req(group, req_join_state, req);
    }

    /* Handle leaves */
    if (group->state == MCAST_IDLE) {
        req_join_state = get_leave_state(group);
        if (req_join_state) {
            group->rec.scope_join_state &= ~req_join_state;
            group->prev_state = group->state;
            if (send_leave_to_wire(group, req_join_state)) {
                group->state = group->prev_state;
                ++rc;
            } else
                group->state = MCAST_LEAVE_SENT;
        }
    }

    if (!list_empty(&group->pending_list) && group->state == MCAST_IDLE)
        goto process_requests;
    mutex_unlock(&group->lock);

    while (rc--)
        release_group(group, 0);
}

static struct mcast_group *search_relocate_mgid0_group(struct mlx4_ib_demux_ctx *ctx,
                               __be64 tid,
                               union ib_gid *new_mgid)
{
    struct mcast_group *group = NULL, *cur_group;
    struct mcast_req *req;
    struct list_head *pos;
    struct list_head *n;

    mutex_lock(&ctx->mcg_table_lock);
    list_for_each_safe(pos, n, &ctx->mcg_mgid0_list) {
        group = list_entry(pos, struct mcast_group, mgid0_list);
        mutex_lock(&group->lock);
        if (group->last_req_tid == tid) {
            if (memcmp(new_mgid, &mgid0, sizeof mgid0)) {
                group->rec.mgid = *new_mgid;
                sprintf(group->name, "%016llx%016llx",
                        be64_to_cpu(group->rec.mgid.global.subnet_prefix),
                        be64_to_cpu(group->rec.mgid.global.interface_id));
                list_del_init(&group->mgid0_list);
                cur_group = mcast_insert(ctx, group);
                if (cur_group) {
                    /* A race between our code and SM. Silently cleaning the new one */
                    req = list_first_entry(&group->pending_list,
                                   struct mcast_req, group_list);
                    --group->func[req->func].num_pend_reqs;
                    list_del(&req->group_list);
                    list_del(&req->func_list);
                    kfree(req);
                    mutex_unlock(&group->lock);
                    mutex_unlock(&ctx->mcg_table_lock);
                    release_group(group, 0);
                    return NULL;
                }

                atomic_inc(&group->refcount);
                add_sysfs_port_mcg_attr(ctx->dev, ctx->port, &group->dentry.attr);
                mutex_unlock(&group->lock);
                mutex_unlock(&ctx->mcg_table_lock);
                return group;
            } else {
                struct mcast_req *tmp1, *tmp2;

                list_del(&group->mgid0_list);
                if (!list_empty(&group->pending_list) && group->state != MCAST_IDLE)
                    cancel_delayed_work_sync(&group->timeout_work);

                list_for_each_entry_safe(tmp1, tmp2, &group->pending_list, group_list) {
                    list_del(&tmp1->group_list);
                    kfree(tmp1);
                }
                mutex_unlock(&group->lock);
                mutex_unlock(&ctx->mcg_table_lock);
                kfree(group);
                return NULL;
            }
        }
        mutex_unlock(&group->lock);
    }
    mutex_unlock(&ctx->mcg_table_lock);

    return NULL;
}

static ssize_t sysfs_show_group(struct device *dev,
        struct device_attribute *attr, char *buf);

static struct mcast_group *acquire_group(struct mlx4_ib_demux_ctx *ctx,
                     union ib_gid *mgid, int create,
                     gfp_t gfp_mask)
{
    struct mcast_group *group, *cur_group;
    int is_mgid0;
    int i;

    is_mgid0 = !memcmp(&mgid0, mgid, sizeof mgid0);
    if (!is_mgid0) {
        group = mcast_find(ctx, mgid);
        if (group)
            goto found;
    }

    if (!create)
        return ERR_PTR(-ENOENT);

    group = kzalloc(sizeof *group, gfp_mask);
    if (!group)
        return ERR_PTR(-ENOMEM);

    group->demux = ctx;
    group->rec.mgid = *mgid;
    INIT_LIST_HEAD(&group->pending_list);
    INIT_LIST_HEAD(&group->mgid0_list);
    for (i = 0; i < MAX_VFS; ++i)
        INIT_LIST_HEAD(&group->func[i].pending);
    INIT_WORK(&group->work, mlx4_ib_mcg_work_handler);
    INIT_DELAYED_WORK(&group->timeout_work, mlx4_ib_mcg_timeout_handler);
    mutex_init(&group->lock);
    sprintf(group->name, "%016llx%016llx",
            be64_to_cpu(group->rec.mgid.global.subnet_prefix),
            be64_to_cpu(group->rec.mgid.global.interface_id));
    sysfs_attr_init(&group->dentry.attr);
    group->dentry.show = sysfs_show_group;
    group->dentry.store = NULL;
    group->dentry.attr.name = group->name;
    group->dentry.attr.mode = 0400;
    group->state = MCAST_IDLE;

    if (is_mgid0) {
        list_add(&group->mgid0_list, &ctx->mcg_mgid0_list);
        goto found;
    }

    cur_group = mcast_insert(ctx, group);
    if (cur_group) {
        mcg_warn("group just showed up %s - confused\n", cur_group->name);
        kfree(group);
        return ERR_PTR(-EINVAL);
    }

    add_sysfs_port_mcg_attr(ctx->dev, ctx->port, &group->dentry.attr);

found:
    atomic_inc(&group->refcount);
    return group;
}

static void queue_req(struct mcast_req *req)
{
    struct mcast_group *group = req->group;

    atomic_inc(&group->refcount); /* for the request */
    atomic_inc(&group->refcount); /* for scheduling the work */
    list_add_tail(&req->group_list, &group->pending_list);
    list_add_tail(&req->func_list, &group->func[req->func].pending);
    /* calls mlx4_ib_mcg_work_handler */
    if (!queue_work(group->demux->mcg_wq, &group->work))
        safe_atomic_dec(&group->refcount);
}

int mlx4_ib_mcg_demux_handler(struct ib_device *ibdev, int port, int slave,
                  struct ib_sa_mad *mad)
{
    struct mlx4_ib_dev *dev = to_mdev(ibdev);
    struct ib_sa_mcmember_data *rec = (struct ib_sa_mcmember_data *)mad->data;
    struct mlx4_ib_demux_ctx *ctx = &dev->sriov.demux[port - 1];
    struct mcast_group *group;

    switch (mad->mad_hdr.method) {
    case IB_MGMT_METHOD_GET_RESP:
    case IB_SA_METHOD_DELETE_RESP:
        mutex_lock(&ctx->mcg_table_lock);
        group = acquire_group(ctx, &rec->mgid, 0, GFP_KERNEL);
        mutex_unlock(&ctx->mcg_table_lock);
        if (IS_ERR(group)) {
            if (mad->mad_hdr.method == IB_MGMT_METHOD_GET_RESP) {
                __be64 tid = mad->mad_hdr.tid;
                *(u8 *)(&tid) = (u8)slave; /* in group we kept the modified TID */
                group = search_relocate_mgid0_group(ctx, tid, &rec->mgid);
            } else
                group = NULL;
        }

        if (!group)
            return 1;

        mutex_lock(&group->lock);
        group->response_sa_mad = *mad;
        group->prev_state = group->state;
        group->state = MCAST_RESP_READY;
        /* calls mlx4_ib_mcg_work_handler */
        atomic_inc(&group->refcount);
        if (!queue_work(ctx->mcg_wq, &group->work))
            safe_atomic_dec(&group->refcount);
        mutex_unlock(&group->lock);
        release_group(group, 0);
        return 1; /* consumed */
    case IB_MGMT_METHOD_SET:
    case IB_SA_METHOD_GET_TABLE:
    case IB_SA_METHOD_GET_TABLE_RESP:
    case IB_SA_METHOD_DELETE:
        return 0; /* not consumed, pass-through to guest over tunnel */
    default:
        mcg_warn("In demux, port %d: unexpected MCMember method: 0x%x, dropping\n",
            port, mad->mad_hdr.method);
        return 1; /* consumed */
    }
}

int mlx4_ib_mcg_multiplex_handler(struct ib_device *ibdev, int port,
                  int slave, struct ib_sa_mad *sa_mad)
{
    struct mlx4_ib_dev *dev = to_mdev(ibdev);
    struct ib_sa_mcmember_data *rec = (struct ib_sa_mcmember_data *)sa_mad->data;
    struct mlx4_ib_demux_ctx *ctx = &dev->sriov.demux[port - 1];
    struct mcast_group *group;
    struct mcast_req *req;
    int may_create = 0;

    if (ctx->flushing)
        return -EAGAIN;

    switch (sa_mad->mad_hdr.method) {
    case IB_MGMT_METHOD_SET:
        may_create = 1;
    case IB_SA_METHOD_DELETE:
        req = kzalloc(sizeof *req, GFP_KERNEL);
        if (!req)
            return -ENOMEM;

        req->func = slave;
        req->sa_mad = *sa_mad;

        mutex_lock(&ctx->mcg_table_lock);
        group = acquire_group(ctx, &rec->mgid, may_create, GFP_KERNEL);
        mutex_unlock(&ctx->mcg_table_lock);
        if (IS_ERR(group)) {
            kfree(req);
            return PTR_ERR(group);
        }
        mutex_lock(&group->lock);
        if (group->func[slave].num_pend_reqs > MAX_PEND_REQS_PER_FUNC) {
            mutex_unlock(&group->lock);
            mcg_warn_group(group, "Port %d, Func %d has too many pending requests (%d), dropping\n",
                       port, slave, MAX_PEND_REQS_PER_FUNC);
            release_group(group, 0);
            kfree(req);
            return -ENOMEM;
        }
        ++group->func[slave].num_pend_reqs;
        req->group = group;
        queue_req(req);
        mutex_unlock(&group->lock);
        release_group(group, 0);
        return 1; /* consumed */
    case IB_SA_METHOD_GET_TABLE:
    case IB_MGMT_METHOD_GET_RESP:
    case IB_SA_METHOD_GET_TABLE_RESP:
    case IB_SA_METHOD_DELETE_RESP:
        return 0; /* not consumed, pass-through */
    default:
        mcg_warn("In multiplex, port %d, func %d: unexpected MCMember method: 0x%x, dropping\n",
            port, slave, sa_mad->mad_hdr.method);
        return 1; /* consumed */
    }
}

static ssize_t sysfs_show_group(struct device *dev,
        struct device_attribute *attr, char *buf)
{
    struct mcast_group *group =
        container_of(attr, struct mcast_group, dentry);
    struct mcast_req *req = NULL;
    char pending_str[40];
    char state_str[40];
    ssize_t len = 0;
    int f;

    if (group->state == MCAST_IDLE)
        sprintf(state_str, "%s", get_state_string(group->state));
    else
        sprintf(state_str, "%s(TID=0x%llx)",
                get_state_string(group->state),
                be64_to_cpu(group->last_req_tid));
    if (list_empty(&group->pending_list)) {
        sprintf(pending_str, "No");
    } else {
        req = list_first_entry(&group->pending_list, struct mcast_req, group_list);
        sprintf(pending_str, "Yes(TID=0x%llx)",
                be64_to_cpu(req->sa_mad.mad_hdr.tid));
    }
    len += sprintf(buf + len, "%1d [%02d,%02d,%02d] %4d %4s %5s     ",
            group->rec.scope_join_state & 0xf,
            group->members[2], group->members[1], group->members[0],
            atomic_read(&group->refcount),
            pending_str,
            state_str);
    for (f = 0; f < MAX_VFS; ++f)
        if (group->func[f].state == MCAST_MEMBER)
            len += sprintf(buf + len, "%d[%1x] ",
                    f, group->func[f].join_state);

    len += sprintf(buf + len, "\t\t(%4hx %4x %2x %2x %2x %2x %2x "
        "%4x %4x %2x %2x)\n",
        be16_to_cpu(group->rec.pkey),
        be32_to_cpu(group->rec.qkey),
        (group->rec.mtusel_mtu & 0xc0) >> 6,
        group->rec.mtusel_mtu & 0x3f,
        group->rec.tclass,
        (group->rec.ratesel_rate & 0xc0) >> 6,
        group->rec.ratesel_rate & 0x3f,
        (be32_to_cpu(group->rec.sl_flowlabel_hoplimit) & 0xf0000000) >> 28,
        (be32_to_cpu(group->rec.sl_flowlabel_hoplimit) & 0x0fffff00) >> 8,
        be32_to_cpu(group->rec.sl_flowlabel_hoplimit) & 0x000000ff,
        group->rec.proxy_join);

    return len;
}

int mlx4_ib_mcg_port_init(struct mlx4_ib_demux_ctx *ctx)
{
    char name[20];

    atomic_set(&ctx->tid, 0);
    sprintf(name, "mlx4_ib_mcg%d", ctx->port);
    ctx->mcg_wq = create_singlethread_workqueue(name);
    if (!ctx->mcg_wq)
        return -ENOMEM;

    mutex_init(&ctx->mcg_table_lock);
    ctx->mcg_table = RB_ROOT;
    INIT_LIST_HEAD(&ctx->mcg_mgid0_list);
    ctx->flushing = 0;

    return 0;
}

static void force_clean_group(struct mcast_group *group)
{
    struct mcast_req *req, *tmp
        ;
    list_for_each_entry_safe(req, tmp, &group->pending_list, group_list) {
        list_del(&req->group_list);
        kfree(req);
    }
    del_sysfs_port_mcg_attr(group->demux->dev, group->demux->port, &group->dentry.attr);
    rb_erase(&group->node, &group->demux->mcg_table);
    kfree(group);
}

static void _mlx4_ib_mcg_port_cleanup(struct mlx4_ib_demux_ctx *ctx, int destroy_wq)
{
    int i;
    struct rb_node *p;
    struct mcast_group *group;
    unsigned long end;
    int count;

    for (i = 0; i < MAX_VFS; ++i)
        clean_vf_mcast(ctx, i);

    end = jiffies + msecs_to_jiffies(MAD_TIMEOUT_MS + 3000);
    do {
        count = 0;
        mutex_lock(&ctx->mcg_table_lock);
        for (p = rb_first(&ctx->mcg_table); p; p = rb_next(p))
            ++count;
        mutex_unlock(&ctx->mcg_table_lock);
        if (!count)
            break;

        msleep(1);
    } while (time_after(end, jiffies));

    flush_workqueue(ctx->mcg_wq);
    if (destroy_wq)
        destroy_workqueue(ctx->mcg_wq);

    mutex_lock(&ctx->mcg_table_lock);
    while ((p = rb_first(&ctx->mcg_table)) != NULL) {
        group = rb_entry(p, struct mcast_group, node);
        if (atomic_read(&group->refcount))
            mcg_warn_group(group, "group refcount %d!!! (pointer %p)\n", atomic_read(&group->refcount), group);

        force_clean_group(group);
    }
    mutex_unlock(&ctx->mcg_table_lock);
}

struct clean_work {
    struct work_struct work;
    struct mlx4_ib_demux_ctx *ctx;
    int destroy_wq;
};

static void mcg_clean_task(struct work_struct *work)
{
    struct clean_work *cw = container_of(work, struct clean_work, work);

    _mlx4_ib_mcg_port_cleanup(cw->ctx, cw->destroy_wq);
    cw->ctx->flushing = 0;
    kfree(cw);
}

void mlx4_ib_mcg_port_cleanup(struct mlx4_ib_demux_ctx *ctx, int destroy_wq)
{
    struct clean_work *work;

    if (ctx->flushing)
        return;

    ctx->flushing = 1;

    if (destroy_wq) {
        _mlx4_ib_mcg_port_cleanup(ctx, destroy_wq);
        ctx->flushing = 0;
        return;
    }

    work = kmalloc(sizeof *work, GFP_KERNEL);
    if (!work) {
        ctx->flushing = 0;
        mcg_warn("failed allocating work for cleanup\n");
        return;
    }

    work->ctx = ctx;
    work->destroy_wq = destroy_wq;
    INIT_WORK(&work->work, mcg_clean_task);
    queue_work(clean_wq, &work->work);
}

static void build_leave_mad(struct mcast_req *req)
{
    struct ib_sa_mad *mad = &req->sa_mad;

    mad->mad_hdr.method = IB_SA_METHOD_DELETE;
}


static void clear_pending_reqs(struct mcast_group *group, int vf)
{
    struct mcast_req *req, *tmp, *group_first = NULL;
    int clear;
    int pend = 0;

    if (!list_empty(&group->pending_list))
        group_first = list_first_entry(&group->pending_list, struct mcast_req, group_list);

    list_for_each_entry_safe(req, tmp, &group->func[vf].pending, func_list) {
        clear = 1;
        if (group_first == req &&
            (group->state == MCAST_JOIN_SENT ||
             group->state == MCAST_LEAVE_SENT)) {
            clear = cancel_delayed_work(&group->timeout_work);
            pend = !clear;
            group->state = MCAST_IDLE;
        }
        if (clear) {
            --group->func[vf].num_pend_reqs;
            list_del(&req->group_list);
            list_del(&req->func_list);
            kfree(req);
            atomic_dec(&group->refcount);
        }
    }

    if (!pend && (!list_empty(&group->func[vf].pending) || group->func[vf].num_pend_reqs)) {
        mcg_warn_group(group, "DRIVER BUG: list_empty %d, num_pend_reqs %d\n",
                   list_empty(&group->func[vf].pending), group->func[vf].num_pend_reqs);
    }
}

static int push_deleteing_req(struct mcast_group *group, int slave)
{
    struct mcast_req *req;
    struct mcast_req *pend_req;

    if (!group->func[slave].join_state)
        return 0;

    req = kzalloc(sizeof *req, GFP_KERNEL);
    if (!req) {
        mcg_warn_group(group, "failed allocation - may leave stall groups\n");
        return -ENOMEM;
    }

    if (!list_empty(&group->func[slave].pending)) {
        pend_req = list_entry(group->func[slave].pending.prev, struct mcast_req, group_list);
        if (pend_req->clean) {
            kfree(req);
            return 0;
        }
    }

    req->clean = 1;
    req->func = slave;
    req->group = group;
    ++group->func[slave].num_pend_reqs;
    build_leave_mad(req);
    queue_req(req);
    return 0;
}

void clean_vf_mcast(struct mlx4_ib_demux_ctx *ctx, int slave)
{
    struct mcast_group *group;
    struct rb_node *p;

    mutex_lock(&ctx->mcg_table_lock);
    for (p = rb_first(&ctx->mcg_table); p; p = rb_next(p)) {
        group = rb_entry(p, struct mcast_group, node);
        mutex_lock(&group->lock);
        if (atomic_read(&group->refcount)) {
            /* clear pending requests of this VF */
            clear_pending_reqs(group, slave);
            push_deleteing_req(group, slave);
        }
        mutex_unlock(&group->lock);
    }
    mutex_unlock(&ctx->mcg_table_lock);
}


int mlx4_ib_mcg_init(void)
{
    clean_wq = create_singlethread_workqueue("mlx4_ib_mcg");
    if (!clean_wq)
        return -ENOMEM;

    return 0;
}

void mlx4_ib_mcg_destroy(void)
{
    destroy_workqueue(clean_wq);
}