/*
 * 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);
}