Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma

[mirror_ubuntu-artful-kernel.git] / drivers / infiniband / ulp / ipoib / ipoib_multicast.c

/*
 * Copyright (c) 2004, 2005 Topspin Communications.  All rights reserved.
 * Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
 * Copyright (c) 2004 Voltaire, Inc. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <linux/skbuff.h>
#include <linux/rtnetlink.h>
#include <linux/moduleparam.h>
#include <linux/ip.h>
#include <linux/in.h>
#include <linux/igmp.h>
#include <linux/inetdevice.h>
#include <linux/delay.h>
#include <linux/completion.h>
#include <linux/slab.h>

#include <net/dst.h>

#include "ipoib.h"

#ifdef CONFIG_INFINIBAND_IPOIB_DEBUG
static int mcast_debug_level;

module_param(mcast_debug_level, int, 0644);
MODULE_PARM_DESC(mcast_debug_level,
                 "Enable multicast debug tracing if > 0");
#endif

struct ipoib_mcast_iter {
        struct net_device *dev;
        union ib_gid       mgid;
        unsigned long      created;
        unsigned int       queuelen;
        unsigned int       complete;
        unsigned int       send_only;
};

/* join state that allows creating mcg with sendonly member request */
#define SENDONLY_FULLMEMBER_JOIN        8

/*
 * This should be called with the priv->lock held
 */
static void __ipoib_mcast_schedule_join_thread(struct ipoib_dev_priv *priv,
                                               struct ipoib_mcast *mcast,
                                               bool delay)
{
        if (!test_bit(IPOIB_FLAG_OPER_UP, &priv->flags))
                return;

        /*
         * We will be scheduling *something*, so cancel whatever is
         * currently scheduled first
         */
        cancel_delayed_work(&priv->mcast_task);
        if (mcast && delay) {
                /*
                 * We had a failure and want to schedule a retry later
                 */
                mcast->backoff *= 2;
                if (mcast->backoff > IPOIB_MAX_BACKOFF_SECONDS)
                        mcast->backoff = IPOIB_MAX_BACKOFF_SECONDS;
                mcast->delay_until = jiffies + (mcast->backoff * HZ);
                /*
                 * Mark this mcast for its delay, but restart the
                 * task immediately.  The join task will make sure to
                 * clear out all entries without delays, and then
                 * schedule itself to run again when the earliest
                 * delay expires
                 */
                queue_delayed_work(priv->wq, &priv->mcast_task, 0);
        } else if (delay) {
                /*
                 * Special case of retrying after a failure to
                 * allocate the broadcast multicast group, wait
                 * 1 second and try again
                 */
                queue_delayed_work(priv->wq, &priv->mcast_task, HZ);
        } else
                queue_delayed_work(priv->wq, &priv->mcast_task, 0);
}

static void ipoib_mcast_free(struct ipoib_mcast *mcast)
{
        struct net_device *dev = mcast->dev;
        int tx_dropped = 0;

        ipoib_dbg_mcast(netdev_priv(dev), "deleting multicast group %pI6\n",
                        mcast->mcmember.mgid.raw);

        /* remove all neigh connected to this mcast */
        ipoib_del_neighs_by_gid(dev, mcast->mcmember.mgid.raw);

        if (mcast->ah)
                ipoib_put_ah(mcast->ah);

        while (!skb_queue_empty(&mcast->pkt_queue)) {
                ++tx_dropped;
                dev_kfree_skb_any(skb_dequeue(&mcast->pkt_queue));
        }

        netif_tx_lock_bh(dev);
        dev->stats.tx_dropped += tx_dropped;
        netif_tx_unlock_bh(dev);

        kfree(mcast);
}

static struct ipoib_mcast *ipoib_mcast_alloc(struct net_device *dev,
                                             int can_sleep)
{
        struct ipoib_mcast *mcast;

        mcast = kzalloc(sizeof *mcast, can_sleep ? GFP_KERNEL : GFP_ATOMIC);
        if (!mcast)
                return NULL;

        mcast->dev = dev;
        mcast->created = jiffies;
        mcast->delay_until = jiffies;
        mcast->backoff = 1;

        INIT_LIST_HEAD(&mcast->list);
        INIT_LIST_HEAD(&mcast->neigh_list);
        skb_queue_head_init(&mcast->pkt_queue);

        return mcast;
}

static struct ipoib_mcast *__ipoib_mcast_find(struct net_device *dev, void *mgid)
{
        struct ipoib_dev_priv *priv = netdev_priv(dev);
        struct rb_node *n = priv->multicast_tree.rb_node;

        while (n) {
                struct ipoib_mcast *mcast;
                int ret;

                mcast = rb_entry(n, struct ipoib_mcast, rb_node);

                ret = memcmp(mgid, mcast->mcmember.mgid.raw,
                             sizeof (union ib_gid));
                if (ret < 0)
                        n = n->rb_left;
                else if (ret > 0)
                        n = n->rb_right;
                else
                        return mcast;
        }

        return NULL;
}

static int __ipoib_mcast_add(struct net_device *dev, struct ipoib_mcast *mcast)
{
        struct ipoib_dev_priv *priv = netdev_priv(dev);
        struct rb_node **n = &priv->multicast_tree.rb_node, *pn = NULL;

        while (*n) {
                struct ipoib_mcast *tmcast;
                int ret;

                pn = *n;
                tmcast = rb_entry(pn, struct ipoib_mcast, rb_node);

                ret = memcmp(mcast->mcmember.mgid.raw, tmcast->mcmember.mgid.raw,
                             sizeof (union ib_gid));
                if (ret < 0)
                        n = &pn->rb_left;
                else if (ret > 0)
                        n = &pn->rb_right;
                else
                        return -EEXIST;
        }

        rb_link_node(&mcast->rb_node, pn, n);
        rb_insert_color(&mcast->rb_node, &priv->multicast_tree);

        return 0;
}

static int ipoib_mcast_join_finish(struct ipoib_mcast *mcast,
                                   struct ib_sa_mcmember_rec *mcmember)
{
        struct net_device *dev = mcast->dev;
        struct ipoib_dev_priv *priv = netdev_priv(dev);
        struct ipoib_ah *ah;
        int ret;
        int set_qkey = 0;

        mcast->mcmember = *mcmember;

        /* Set the multicast MTU and cached Q_Key before we attach if it's
         * the broadcast group.
         */
        if (!memcmp(mcast->mcmember.mgid.raw, priv->dev->broadcast + 4,
                    sizeof (union ib_gid))) {
                spin_lock_irq(&priv->lock);
                if (!priv->broadcast) {
                        spin_unlock_irq(&priv->lock);
                        return -EAGAIN;
                }
                /*update priv member according to the new mcast*/
                priv->broadcast->mcmember.qkey = mcmember->qkey;
                priv->broadcast->mcmember.mtu = mcmember->mtu;
                priv->broadcast->mcmember.traffic_class = mcmember->traffic_class;
                priv->broadcast->mcmember.rate = mcmember->rate;
                priv->broadcast->mcmember.sl = mcmember->sl;
                priv->broadcast->mcmember.flow_label = mcmember->flow_label;
                priv->broadcast->mcmember.hop_limit = mcmember->hop_limit;
                /* assume if the admin and the mcast are the same both can be changed */
                if (priv->mcast_mtu == priv->admin_mtu)
                        priv->admin_mtu =
                        priv->mcast_mtu =
                        IPOIB_UD_MTU(ib_mtu_enum_to_int(priv->broadcast->mcmember.mtu));
                else
                        priv->mcast_mtu =
                        IPOIB_UD_MTU(ib_mtu_enum_to_int(priv->broadcast->mcmember.mtu));

                priv->qkey = be32_to_cpu(priv->broadcast->mcmember.qkey);
                spin_unlock_irq(&priv->lock);
                priv->tx_wr.remote_qkey = priv->qkey;
                set_qkey = 1;
        }

        if (!test_bit(IPOIB_MCAST_FLAG_SENDONLY, &mcast->flags)) {
                if (test_and_set_bit(IPOIB_MCAST_FLAG_ATTACHED, &mcast->flags)) {
                        ipoib_warn(priv, "multicast group %pI6 already attached\n",
                                   mcast->mcmember.mgid.raw);

                        return 0;
                }

                ret = ipoib_mcast_attach(dev, be16_to_cpu(mcast->mcmember.mlid),
                                         &mcast->mcmember.mgid, set_qkey);
                if (ret < 0) {
                        ipoib_warn(priv, "couldn't attach QP to multicast group %pI6\n",
                                   mcast->mcmember.mgid.raw);

                        clear_bit(IPOIB_MCAST_FLAG_ATTACHED, &mcast->flags);
                        return ret;
                }
        }

        {
                struct ib_ah_attr av = {
                        .dlid          = be16_to_cpu(mcast->mcmember.mlid),
                        .port_num      = priv->port,
                        .sl            = mcast->mcmember.sl,
                        .ah_flags      = IB_AH_GRH,
                        .static_rate   = mcast->mcmember.rate,
                        .grh           = {
                                .flow_label    = be32_to_cpu(mcast->mcmember.flow_label),
                                .hop_limit     = mcast->mcmember.hop_limit,
                                .sgid_index    = 0,
                                .traffic_class = mcast->mcmember.traffic_class
                        }
                };
                av.grh.dgid = mcast->mcmember.mgid;

                ah = ipoib_create_ah(dev, priv->pd, &av);
                if (IS_ERR(ah)) {
                        ipoib_warn(priv, "ib_address_create failed %ld\n",
                                -PTR_ERR(ah));
                        /* use original error */
                        return PTR_ERR(ah);
                } else {
                        spin_lock_irq(&priv->lock);
                        mcast->ah = ah;
                        spin_unlock_irq(&priv->lock);

                        ipoib_dbg_mcast(priv, "MGID %pI6 AV %p, LID 0x%04x, SL %d\n",
                                        mcast->mcmember.mgid.raw,
                                        mcast->ah->ah,
                                        be16_to_cpu(mcast->mcmember.mlid),
                                        mcast->mcmember.sl);
                }
        }

        /* actually send any queued packets */
        netif_tx_lock_bh(dev);
        while (!skb_queue_empty(&mcast->pkt_queue)) {
                struct sk_buff *skb = skb_dequeue(&mcast->pkt_queue);

                netif_tx_unlock_bh(dev);

                skb->dev = dev;
                if (dev_queue_xmit(skb))
                        ipoib_warn(priv, "dev_queue_xmit failed to requeue packet\n");

                netif_tx_lock_bh(dev);
        }
        netif_tx_unlock_bh(dev);

        return 0;
}

void ipoib_mcast_carrier_on_task(struct work_struct *work)
{
        struct ipoib_dev_priv *priv = container_of(work, struct ipoib_dev_priv,
                                                   carrier_on_task);
        struct ib_port_attr attr;
        int ret;

        if (ib_query_port(priv->ca, priv->port, &attr) ||
            attr.state != IB_PORT_ACTIVE) {
                ipoib_dbg(priv, "Keeping carrier off until IB port is active\n");
                return;
        }
        /*
         * Check if can send sendonly MCG's with sendonly-fullmember join state.
         * It done here after the successfully join to the broadcast group,
         * because the broadcast group must always be joined first and is always
         * re-joined if the SM changes substantially.
         */
        ret = ipoib_check_sm_sendonly_fullmember_support(priv);
        if (ret < 0)
                pr_debug("%s failed query sm support for sendonly-fullmember (ret: %d)\n",
                         priv->dev->name, ret);

        /*
         * Take rtnl_lock to avoid racing with ipoib_stop() and
         * turning the carrier back on while a device is being
         * removed.  However, ipoib_stop() will attempt to flush
         * the workqueue while holding the rtnl lock, so loop
         * on trylock until either we get the lock or we see
         * FLAG_OPER_UP go away as that signals that we are bailing
         * and can safely ignore the carrier on work.
         */
        while (!rtnl_trylock()) {
                if (!test_bit(IPOIB_FLAG_OPER_UP, &priv->flags))
                        return;
                else
                        msleep(20);
        }
        if (!ipoib_cm_admin_enabled(priv->dev))
                dev_set_mtu(priv->dev, min(priv->mcast_mtu, priv->admin_mtu));
        netif_carrier_on(priv->dev);
        rtnl_unlock();
}

static int ipoib_mcast_join_complete(int status,
                                     struct ib_sa_multicast *multicast)
{
        struct ipoib_mcast *mcast = multicast->context;
        struct net_device *dev = mcast->dev;
        struct ipoib_dev_priv *priv = netdev_priv(dev);

        ipoib_dbg_mcast(priv, "%sjoin completion for %pI6 (status %d)\n",
                        test_bit(IPOIB_MCAST_FLAG_SENDONLY, &mcast->flags) ?
                        "sendonly " : "",
                        mcast->mcmember.mgid.raw, status);

        /* We trap for port events ourselves. */
        if (status == -ENETRESET) {
                status = 0;
                goto out;
        }

        if (!status)
                status = ipoib_mcast_join_finish(mcast, &multicast->rec);

        if (!status) {
                mcast->backoff = 1;
                mcast->delay_until = jiffies;

                /*
                 * Defer carrier on work to priv->wq to avoid a
                 * deadlock on rtnl_lock here.  Requeue our multicast
                 * work too, which will end up happening right after
                 * our carrier on task work and will allow us to
                 * send out all of the non-broadcast joins
                 */
                if (mcast == priv->broadcast) {
                        spin_lock_irq(&priv->lock);
                        queue_work(priv->wq, &priv->carrier_on_task);
                        __ipoib_mcast_schedule_join_thread(priv, NULL, 0);
                        goto out_locked;
                }
        } else {
                bool silent_fail =
                    test_bit(IPOIB_MCAST_FLAG_SENDONLY, &mcast->flags) &&
                    status == -EINVAL;

                if (mcast->logcount < 20) {
                        if (status == -ETIMEDOUT || status == -EAGAIN ||
                            silent_fail) {
                                ipoib_dbg_mcast(priv, "%smulticast join failed for %pI6, status %d\n",
                                                test_bit(IPOIB_MCAST_FLAG_SENDONLY, &mcast->flags) ? "sendonly " : "",
                                                mcast->mcmember.mgid.raw, status);
                        } else {
                                ipoib_warn(priv, "%smulticast join failed for %pI6, status %d\n",
                                                test_bit(IPOIB_MCAST_FLAG_SENDONLY, &mcast->flags) ? "sendonly " : "",
                                           mcast->mcmember.mgid.raw, status);
                        }

                        if (!silent_fail)
                                mcast->logcount++;
                }

                if (test_bit(IPOIB_MCAST_FLAG_SENDONLY, &mcast->flags) &&
                    mcast->backoff >= 2) {
                        /*
                         * We only retry sendonly joins once before we drop
                         * the packet and quit trying to deal with the
                         * group.  However, we leave the group in the
                         * mcast list as an unjoined group.  If we want to
                         * try joining again, we simply queue up a packet
                         * and restart the join thread.  The empty queue
                         * is why the join thread ignores this group.
                         */
                        mcast->backoff = 1;
                        netif_tx_lock_bh(dev);
                        while (!skb_queue_empty(&mcast->pkt_queue)) {
                                ++dev->stats.tx_dropped;
                                dev_kfree_skb_any(skb_dequeue(&mcast->pkt_queue));
                        }
                        netif_tx_unlock_bh(dev);
                } else {
                        spin_lock_irq(&priv->lock);
                        /* Requeue this join task with a backoff delay */
                        __ipoib_mcast_schedule_join_thread(priv, mcast, 1);
                        goto out_locked;
                }
        }
out:
        spin_lock_irq(&priv->lock);
out_locked:
        /*
         * Make sure to set mcast->mc before we clear the busy flag to avoid
         * racing with code that checks for BUSY before checking mcast->mc
         */
        if (status)
                mcast->mc = NULL;
        else
                mcast->mc = multicast;
        clear_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags);
        spin_unlock_irq(&priv->lock);
        complete(&mcast->done);

        return status;
}

/*
 * Caller must hold 'priv->lock'
 */
static int ipoib_mcast_join(struct net_device *dev, struct ipoib_mcast *mcast)
{
        struct ipoib_dev_priv *priv = netdev_priv(dev);
        struct ib_sa_multicast *multicast;
        struct ib_sa_mcmember_rec rec = {
                .join_state = 1
        };
        ib_sa_comp_mask comp_mask;
        int ret = 0;

        if (!priv->broadcast ||
            !test_bit(IPOIB_FLAG_OPER_UP, &priv->flags))
                return -EINVAL;

        ipoib_dbg_mcast(priv, "joining MGID %pI6\n", mcast->mcmember.mgid.raw);

        rec.mgid     = mcast->mcmember.mgid;
        rec.port_gid = priv->local_gid;
        rec.pkey     = cpu_to_be16(priv->pkey);

        comp_mask =
                IB_SA_MCMEMBER_REC_MGID         |
                IB_SA_MCMEMBER_REC_PORT_GID     |
                IB_SA_MCMEMBER_REC_PKEY         |
                IB_SA_MCMEMBER_REC_JOIN_STATE;

        if (mcast != priv->broadcast) {
                /*
                 * RFC 4391:
                 *  The MGID MUST use the same P_Key, Q_Key, SL, MTU,
                 *  and HopLimit as those used in the broadcast-GID.  The rest
                 *  of attributes SHOULD follow the values used in the
                 *  broadcast-GID as well.
                 */
                comp_mask |=
                        IB_SA_MCMEMBER_REC_QKEY                 |
                        IB_SA_MCMEMBER_REC_MTU_SELECTOR         |
                        IB_SA_MCMEMBER_REC_MTU                  |
                        IB_SA_MCMEMBER_REC_TRAFFIC_CLASS        |
                        IB_SA_MCMEMBER_REC_RATE_SELECTOR        |
                        IB_SA_MCMEMBER_REC_RATE                 |
                        IB_SA_MCMEMBER_REC_SL                   |
                        IB_SA_MCMEMBER_REC_FLOW_LABEL           |
                        IB_SA_MCMEMBER_REC_HOP_LIMIT;

                rec.qkey          = priv->broadcast->mcmember.qkey;
                rec.mtu_selector  = IB_SA_EQ;
                rec.mtu           = priv->broadcast->mcmember.mtu;
                rec.traffic_class = priv->broadcast->mcmember.traffic_class;
                rec.rate_selector = IB_SA_EQ;
                rec.rate          = priv->broadcast->mcmember.rate;
                rec.sl            = priv->broadcast->mcmember.sl;
                rec.flow_label    = priv->broadcast->mcmember.flow_label;
                rec.hop_limit     = priv->broadcast->mcmember.hop_limit;

                /*
                 * Send-only IB Multicast joins work at the core IB layer but
                 * require specific SM support.
                 * We can use such joins here only if the current SM supports that feature.
                 * However, if not, we emulate an Ethernet multicast send,
                 * which does not require a multicast subscription and will
                 * still send properly. The most appropriate thing to
                 * do is to create the group if it doesn't exist as that
                 * most closely emulates the behavior, from a user space
                 * application perspective, of Ethernet multicast operation.
                 */
                if (test_bit(IPOIB_MCAST_FLAG_SENDONLY, &mcast->flags) &&
                    priv->sm_fullmember_sendonly_support)
                        /* SM supports sendonly-fullmember, otherwise fallback to full-member */
                        rec.join_state = SENDONLY_FULLMEMBER_JOIN;
        }
        spin_unlock_irq(&priv->lock);

        multicast = ib_sa_join_multicast(&ipoib_sa_client, priv->ca, priv->port,
                                         &rec, comp_mask, GFP_KERNEL,
                                         ipoib_mcast_join_complete, mcast);
        spin_lock_irq(&priv->lock);
        if (IS_ERR(multicast)) {
                ret = PTR_ERR(multicast);
                ipoib_warn(priv, "ib_sa_join_multicast failed, status %d\n", ret);
                /* Requeue this join task with a backoff delay */
                __ipoib_mcast_schedule_join_thread(priv, mcast, 1);
                clear_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags);
                spin_unlock_irq(&priv->lock);
                complete(&mcast->done);
                spin_lock_irq(&priv->lock);
        }
        return 0;
}

void ipoib_mcast_join_task(struct work_struct *work)
{
        struct ipoib_dev_priv *priv =
                container_of(work, struct ipoib_dev_priv, mcast_task.work);
        struct net_device *dev = priv->dev;
        struct ib_port_attr port_attr;
        unsigned long delay_until = 0;
        struct ipoib_mcast *mcast = NULL;

        if (!test_bit(IPOIB_FLAG_OPER_UP, &priv->flags))
                return;

        if (ib_query_port(priv->ca, priv->port, &port_attr)) {
                ipoib_dbg(priv, "ib_query_port() failed\n");
                return;
        }
        if (port_attr.state != IB_PORT_ACTIVE) {
                ipoib_dbg(priv, "port state is not ACTIVE (state = %d) suspending join task\n",
                          port_attr.state);
                return;
        }
        priv->local_lid = port_attr.lid;
        netif_addr_lock_bh(dev);

        if (!test_bit(IPOIB_FLAG_DEV_ADDR_SET, &priv->flags)) {
                netif_addr_unlock_bh(dev);
                return;
        }
        netif_addr_unlock_bh(dev);

        spin_lock_irq(&priv->lock);
        if (!test_bit(IPOIB_FLAG_OPER_UP, &priv->flags))
                goto out;

        if (!priv->broadcast) {
                struct ipoib_mcast *broadcast;

                broadcast = ipoib_mcast_alloc(dev, 0);
                if (!broadcast) {
                        ipoib_warn(priv, "failed to allocate broadcast group\n");
                        /*
                         * Restart us after a 1 second delay to retry
                         * creating our broadcast group and attaching to
                         * it.  Until this succeeds, this ipoib dev is
                         * completely stalled (multicast wise).
                         */
                        __ipoib_mcast_schedule_join_thread(priv, NULL, 1);
                        goto out;
                }

                memcpy(broadcast->mcmember.mgid.raw, priv->dev->broadcast + 4,
                       sizeof (union ib_gid));
                priv->broadcast = broadcast;

                __ipoib_mcast_add(dev, priv->broadcast);
        }

        if (!test_bit(IPOIB_MCAST_FLAG_ATTACHED, &priv->broadcast->flags)) {
                if (IS_ERR_OR_NULL(priv->broadcast->mc) &&
                    !test_bit(IPOIB_MCAST_FLAG_BUSY, &priv->broadcast->flags)) {
                        mcast = priv->broadcast;
                        if (mcast->backoff > 1 &&
                            time_before(jiffies, mcast->delay_until)) {
                                delay_until = mcast->delay_until;
                                mcast = NULL;
                        }
                }
                goto out;
        }

        /*
         * We'll never get here until the broadcast group is both allocated
         * and attached
         */
        list_for_each_entry(mcast, &priv->multicast_list, list) {
                if (IS_ERR_OR_NULL(mcast->mc) &&
                    !test_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags) &&
                    (!test_bit(IPOIB_MCAST_FLAG_SENDONLY, &mcast->flags) ||
                     !skb_queue_empty(&mcast->pkt_queue))) {
                        if (mcast->backoff == 1 ||
                            time_after_eq(jiffies, mcast->delay_until)) {
                                /* Found the next unjoined group */
                                init_completion(&mcast->done);
                                set_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags);
                                if (ipoib_mcast_join(dev, mcast)) {
                                        spin_unlock_irq(&priv->lock);
                                        return;
                                }
                        } else if (!delay_until ||
                                 time_before(mcast->delay_until, delay_until))
                                delay_until = mcast->delay_until;
                }
        }

        mcast = NULL;
        ipoib_dbg_mcast(priv, "successfully started all multicast joins\n");

out:
        if (delay_until) {
                cancel_delayed_work(&priv->mcast_task);
                queue_delayed_work(priv->wq, &priv->mcast_task,
                                   delay_until - jiffies);
        }
        if (mcast) {
                init_completion(&mcast->done);
                set_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags);
                ipoib_mcast_join(dev, mcast);
        }
        spin_unlock_irq(&priv->lock);
}

int ipoib_mcast_start_thread(struct net_device *dev)
{
        struct ipoib_dev_priv *priv = netdev_priv(dev);
        unsigned long flags;

        ipoib_dbg_mcast(priv, "starting multicast thread\n");

        spin_lock_irqsave(&priv->lock, flags);
        __ipoib_mcast_schedule_join_thread(priv, NULL, 0);
        spin_unlock_irqrestore(&priv->lock, flags);

        return 0;
}

int ipoib_mcast_stop_thread(struct net_device *dev)
{
        struct ipoib_dev_priv *priv = netdev_priv(dev);
        unsigned long flags;

        ipoib_dbg_mcast(priv, "stopping multicast thread\n");

        spin_lock_irqsave(&priv->lock, flags);
        cancel_delayed_work(&priv->mcast_task);
        spin_unlock_irqrestore(&priv->lock, flags);

        flush_workqueue(priv->wq);

        return 0;
}

static int ipoib_mcast_leave(struct net_device *dev, struct ipoib_mcast *mcast)
{
        struct ipoib_dev_priv *priv = netdev_priv(dev);
        int ret = 0;

        if (test_and_clear_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags))
                ipoib_warn(priv, "ipoib_mcast_leave on an in-flight join\n");

        if (!IS_ERR_OR_NULL(mcast->mc))
                ib_sa_free_multicast(mcast->mc);

        if (test_and_clear_bit(IPOIB_MCAST_FLAG_ATTACHED, &mcast->flags)) {
                ipoib_dbg_mcast(priv, "leaving MGID %pI6\n",
                                mcast->mcmember.mgid.raw);

                /* Remove ourselves from the multicast group */
                ret = ib_detach_mcast(priv->qp, &mcast->mcmember.mgid,
                                      be16_to_cpu(mcast->mcmember.mlid));
                if (ret)
                        ipoib_warn(priv, "ib_detach_mcast failed (result = %d)\n", ret);
        } else if (!test_bit(IPOIB_MCAST_FLAG_SENDONLY, &mcast->flags))
                ipoib_dbg(priv, "leaving with no mcmember but not a "
                          "SENDONLY join\n");

        return 0;
}

/*
 * Check if the multicast group is sendonly. If so remove it from the maps
 * and add to the remove list
 */
void ipoib_check_and_add_mcast_sendonly(struct ipoib_dev_priv *priv, u8 *mgid,
                                struct list_head *remove_list)
{
        /* Is this multicast ? */
        if (*mgid == 0xff) {
                struct ipoib_mcast *mcast = __ipoib_mcast_find(priv->dev, mgid);

                if (mcast && test_bit(IPOIB_MCAST_FLAG_SENDONLY, &mcast->flags)) {
                        list_del(&mcast->list);
                        rb_erase(&mcast->rb_node, &priv->multicast_tree);
                        list_add_tail(&mcast->list, remove_list);
                }
        }
}

void ipoib_mcast_remove_list(struct list_head *remove_list)
{
        struct ipoib_mcast *mcast, *tmcast;

        list_for_each_entry_safe(mcast, tmcast, remove_list, list) {
                ipoib_mcast_leave(mcast->dev, mcast);
                ipoib_mcast_free(mcast);
        }
}

void ipoib_mcast_send(struct net_device *dev, u8 *daddr, struct sk_buff *skb)
{
        struct ipoib_dev_priv *priv = netdev_priv(dev);
        struct ipoib_mcast *mcast;
        unsigned long flags;
        void *mgid = daddr + 4;

        spin_lock_irqsave(&priv->lock, flags);

        if (!test_bit(IPOIB_FLAG_OPER_UP, &priv->flags)         ||
            !priv->broadcast                                    ||
            !test_bit(IPOIB_MCAST_FLAG_ATTACHED, &priv->broadcast->flags)) {
                ++dev->stats.tx_dropped;
                dev_kfree_skb_any(skb);
                goto unlock;
        }

        mcast = __ipoib_mcast_find(dev, mgid);
        if (!mcast || !mcast->ah) {
                if (!mcast) {
                        /* Let's create a new send only group now */
                        ipoib_dbg_mcast(priv, "setting up send only multicast group for %pI6\n",
                                        mgid);

                        mcast = ipoib_mcast_alloc(dev, 0);
                        if (!mcast) {
                                ipoib_warn(priv, "unable to allocate memory "
                                           "for multicast structure\n");
                                ++dev->stats.tx_dropped;
                                dev_kfree_skb_any(skb);
                                goto unlock;
                        }

                        set_bit(IPOIB_MCAST_FLAG_SENDONLY, &mcast->flags);
                        memcpy(mcast->mcmember.mgid.raw, mgid,
                               sizeof (union ib_gid));
                        __ipoib_mcast_add(dev, mcast);
                        list_add_tail(&mcast->list, &priv->multicast_list);
                }
                if (skb_queue_len(&mcast->pkt_queue) < IPOIB_MAX_MCAST_QUEUE) {
                        /* put pseudoheader back on for next time */
                        skb_push(skb, sizeof(struct ipoib_pseudo_header));
                        skb_queue_tail(&mcast->pkt_queue, skb);
                } else {
                        ++dev->stats.tx_dropped;
                        dev_kfree_skb_any(skb);
                }
                if (!test_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags)) {
                        __ipoib_mcast_schedule_join_thread(priv, NULL, 0);
                }
        } else {
                struct ipoib_neigh *neigh;

                spin_unlock_irqrestore(&priv->lock, flags);
                neigh = ipoib_neigh_get(dev, daddr);
                spin_lock_irqsave(&priv->lock, flags);
                if (!neigh) {
                        neigh = ipoib_neigh_alloc(daddr, dev);
                        if (neigh) {
                                kref_get(&mcast->ah->ref);
                                neigh->ah       = mcast->ah;
                                list_add_tail(&neigh->list, &mcast->neigh_list);
                        }
                }
                spin_unlock_irqrestore(&priv->lock, flags);
                ipoib_send(dev, skb, mcast->ah, IB_MULTICAST_QPN);
                if (neigh)
                        ipoib_neigh_put(neigh);
                return;
        }

unlock:
        spin_unlock_irqrestore(&priv->lock, flags);
}

void ipoib_mcast_dev_flush(struct net_device *dev)
{
        struct ipoib_dev_priv *priv = netdev_priv(dev);
        LIST_HEAD(remove_list);
        struct ipoib_mcast *mcast, *tmcast;
        unsigned long flags;

        ipoib_dbg_mcast(priv, "flushing multicast list\n");

        spin_lock_irqsave(&priv->lock, flags);

        list_for_each_entry_safe(mcast, tmcast, &priv->multicast_list, list) {
                list_del(&mcast->list);
                rb_erase(&mcast->rb_node, &priv->multicast_tree);
                list_add_tail(&mcast->list, &remove_list);
        }

        if (priv->broadcast) {
                rb_erase(&priv->broadcast->rb_node, &priv->multicast_tree);
                list_add_tail(&priv->broadcast->list, &remove_list);
                priv->broadcast = NULL;
        }

        spin_unlock_irqrestore(&priv->lock, flags);

        /*
         * make sure the in-flight joins have finished before we attempt
         * to leave
         */
        list_for_each_entry_safe(mcast, tmcast, &remove_list, list)
                if (test_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags))
                        wait_for_completion(&mcast->done);

        ipoib_mcast_remove_list(&remove_list);
}

static int ipoib_mcast_addr_is_valid(const u8 *addr, const u8 *broadcast)
{
        /* reserved QPN, prefix, scope */
        if (memcmp(addr, broadcast, 6))
                return 0;
        /* signature lower, pkey */
        if (memcmp(addr + 7, broadcast + 7, 3))
                return 0;
        return 1;
}

void ipoib_mcast_restart_task(struct work_struct *work)
{
        struct ipoib_dev_priv *priv =
                container_of(work, struct ipoib_dev_priv, restart_task);
        struct net_device *dev = priv->dev;
        struct netdev_hw_addr *ha;
        struct ipoib_mcast *mcast, *tmcast;
        LIST_HEAD(remove_list);
        unsigned long flags;
        struct ib_sa_mcmember_rec rec;

        if (!test_bit(IPOIB_FLAG_OPER_UP, &priv->flags))
                /*
                 * shortcut...on shutdown flush is called next, just
                 * let it do all the work
                 */
                return;

        ipoib_dbg_mcast(priv, "restarting multicast task\n");

        local_irq_save(flags);
        netif_addr_lock(dev);
        spin_lock(&priv->lock);

        /*
         * Unfortunately, the networking core only gives us a list of all of
         * the multicast hardware addresses. We need to figure out which ones
         * are new and which ones have been removed
         */

        /* Clear out the found flag */
        list_for_each_entry(mcast, &priv->multicast_list, list)
                clear_bit(IPOIB_MCAST_FLAG_FOUND, &mcast->flags);

        /* Mark all of the entries that are found or don't exist */
        netdev_for_each_mc_addr(ha, dev) {
                union ib_gid mgid;

                if (!ipoib_mcast_addr_is_valid(ha->addr, dev->broadcast))
                        continue;

                memcpy(mgid.raw, ha->addr + 4, sizeof mgid);

                mcast = __ipoib_mcast_find(dev, &mgid);
                if (!mcast || test_bit(IPOIB_MCAST_FLAG_SENDONLY, &mcast->flags)) {
                        struct ipoib_mcast *nmcast;

                        /* ignore group which is directly joined by userspace */
                        if (test_bit(IPOIB_FLAG_UMCAST, &priv->flags) &&
                            !ib_sa_get_mcmember_rec(priv->ca, priv->port, &mgid, &rec)) {
                                ipoib_dbg_mcast(priv, "ignoring multicast entry for mgid %pI6\n",
                                                mgid.raw);
                                continue;
                        }

                        /* Not found or send-only group, let's add a new entry */
                        ipoib_dbg_mcast(priv, "adding multicast entry for mgid %pI6\n",
                                        mgid.raw);

                        nmcast = ipoib_mcast_alloc(dev, 0);
                        if (!nmcast) {
                                ipoib_warn(priv, "unable to allocate memory for multicast structure\n");
                                continue;
                        }

                        set_bit(IPOIB_MCAST_FLAG_FOUND, &nmcast->flags);

                        nmcast->mcmember.mgid = mgid;

                        if (mcast) {
                                /* Destroy the send only entry */
                                list_move_tail(&mcast->list, &remove_list);

                                rb_replace_node(&mcast->rb_node,
                                                &nmcast->rb_node,
                                                &priv->multicast_tree);
                        } else
                                __ipoib_mcast_add(dev, nmcast);

                        list_add_tail(&nmcast->list, &priv->multicast_list);
                }

                if (mcast)
                        set_bit(IPOIB_MCAST_FLAG_FOUND, &mcast->flags);
        }

        /* Remove all of the entries don't exist anymore */
        list_for_each_entry_safe(mcast, tmcast, &priv->multicast_list, list) {
                if (!test_bit(IPOIB_MCAST_FLAG_FOUND, &mcast->flags) &&
                    !test_bit(IPOIB_MCAST_FLAG_SENDONLY, &mcast->flags)) {
                        ipoib_dbg_mcast(priv, "deleting multicast group %pI6\n",
                                        mcast->mcmember.mgid.raw);

                        rb_erase(&mcast->rb_node, &priv->multicast_tree);

                        /* Move to the remove list */
                        list_move_tail(&mcast->list, &remove_list);
                }
        }

        spin_unlock(&priv->lock);
        netif_addr_unlock(dev);
        local_irq_restore(flags);

        /*
         * make sure the in-flight joins have finished before we attempt
         * to leave
         */
        list_for_each_entry_safe(mcast, tmcast, &remove_list, list)
                if (test_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags))
                        wait_for_completion(&mcast->done);

        ipoib_mcast_remove_list(&remove_list);

        /*
         * Double check that we are still up
         */
        if (test_bit(IPOIB_FLAG_OPER_UP, &priv->flags)) {
                spin_lock_irqsave(&priv->lock, flags);
                __ipoib_mcast_schedule_join_thread(priv, NULL, 0);
                spin_unlock_irqrestore(&priv->lock, flags);
        }
}

#ifdef CONFIG_INFINIBAND_IPOIB_DEBUG

struct ipoib_mcast_iter *ipoib_mcast_iter_init(struct net_device *dev)
{
        struct ipoib_mcast_iter *iter;

        iter = kmalloc(sizeof *iter, GFP_KERNEL);
        if (!iter)
                return NULL;

        iter->dev = dev;
        memset(iter->mgid.raw, 0, 16);

        if (ipoib_mcast_iter_next(iter)) {
                kfree(iter);
                return NULL;
        }

        return iter;
}

int ipoib_mcast_iter_next(struct ipoib_mcast_iter *iter)
{
        struct ipoib_dev_priv *priv = netdev_priv(iter->dev);
        struct rb_node *n;
        struct ipoib_mcast *mcast;
        int ret = 1;

        spin_lock_irq(&priv->lock);

        n = rb_first(&priv->multicast_tree);

        while (n) {
                mcast = rb_entry(n, struct ipoib_mcast, rb_node);

                if (memcmp(iter->mgid.raw, mcast->mcmember.mgid.raw,
                           sizeof (union ib_gid)) < 0) {
                        iter->mgid      = mcast->mcmember.mgid;
                        iter->created   = mcast->created;
                        iter->queuelen  = skb_queue_len(&mcast->pkt_queue);
                        iter->complete  = !!mcast->ah;
                        iter->send_only = !!(mcast->flags & (1 << IPOIB_MCAST_FLAG_SENDONLY));

                        ret = 0;

                        break;
                }

                n = rb_next(n);
        }

        spin_unlock_irq(&priv->lock);

        return ret;
}

void ipoib_mcast_iter_read(struct ipoib_mcast_iter *iter,
                           union ib_gid *mgid,
                           unsigned long *created,
                           unsigned int *queuelen,
                           unsigned int *complete,
                           unsigned int *send_only)
{
        *mgid      = iter->mgid;
        *created   = iter->created;
        *queuelen  = iter->queuelen;
        *complete  = iter->complete;
        *send_only = iter->send_only;
}

#endif /* CONFIG_INFINIBAND_IPOIB_DEBUG */