/*-
 * SPDX-License-Identifier: BSD-2-Clause OR GPL-2.0
 *
 * Copyright (c) 2006 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 <sys/cdefs.h>
#include "ipoib.h"

#ifdef CONFIG_INFINIBAND_IPOIB_CM

#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <netinet/icmp6.h>

#include <rdma/ib_cm.h>
#include <rdma/ib_cache.h>
#include <linux/delay.h>

int ipoib_max_conn_qp = 128;

module_param_named(max_nonsrq_conn_qp, ipoib_max_conn_qp, int, 0444);
MODULE_PARM_DESC(max_nonsrq_conn_qp,
                 "Max number of connected-mode QPs per interface "
                 "(applied only if shared receive queue is not available)");

#ifdef CONFIG_INFINIBAND_IPOIB_DEBUG_DATA
static int data_debug_level;

module_param_named(cm_data_debug_level, data_debug_level, int, 0644);
MODULE_PARM_DESC(cm_data_debug_level,
                 "Enable data path debug tracing for connected mode if > 0");
#endif

#define IPOIB_CM_IETF_ID 0x1000000000000000ULL

#define IPOIB_CM_RX_UPDATE_TIME (256 * HZ)
#define IPOIB_CM_RX_TIMEOUT     (2 * 256 * HZ)
#define IPOIB_CM_RX_DELAY       (3 * 256 * HZ)
#define IPOIB_CM_RX_UPDATE_MASK (0x3)

static struct ib_qp_attr ipoib_cm_err_attr = {
        .qp_state = IB_QPS_ERR
};

#define IPOIB_CM_RX_DRAIN_WRID 0xffffffff

static struct ib_send_wr ipoib_cm_rx_drain_wr = {
        .wr_id = IPOIB_CM_RX_DRAIN_WRID,
        .opcode = IB_WR_SEND,
};

static int ipoib_cm_tx_handler(struct ib_cm_id *cm_id,
                               struct ib_cm_event *event);

static void ipoib_cm_dma_unmap_rx(struct ipoib_dev_priv *priv, struct ipoib_cm_rx_buf *rx_req)
{

        ipoib_dma_unmap_rx(priv, (struct ipoib_rx_buf *)rx_req);

}

static int ipoib_cm_post_receive_srq(struct ipoib_dev_priv *priv, int id)
{
        const struct ib_recv_wr *bad_wr;
        struct ipoib_rx_buf *rx_req;
        struct mbuf *m;
        int ret;
        int i;

        rx_req = (struct ipoib_rx_buf *)&priv->cm.srq_ring[id];
        for (m = rx_req->mb, i = 0; m != NULL; m = m->m_next, i++) {
                priv->cm.rx_sge[i].addr = rx_req->mapping[i];
                priv->cm.rx_sge[i].length = m->m_len;
        }

        priv->cm.rx_wr.num_sge = i;
        priv->cm.rx_wr.wr_id = id | IPOIB_OP_CM | IPOIB_OP_RECV;

        ret = ib_post_srq_recv(priv->cm.srq, &priv->cm.rx_wr, &bad_wr);
        if (unlikely(ret)) {
                ipoib_warn(priv, "post srq failed for buf %d (%d)\n", id, ret);
                ipoib_dma_unmap_rx(priv, rx_req);
                m_freem(priv->cm.srq_ring[id].mb);
                priv->cm.srq_ring[id].mb = NULL;
        }

        return ret;
}

static int ipoib_cm_post_receive_nonsrq(struct ipoib_dev_priv *priv,
                                        struct ipoib_cm_rx *rx,
                                        struct ib_recv_wr *wr,
                                        struct ib_sge *sge, int id)
{
        struct ipoib_rx_buf *rx_req;
        const struct ib_recv_wr *bad_wr;
        struct mbuf *m;
        int ret;
        int i;

        rx_req = (struct ipoib_rx_buf *)&rx->rx_ring[id];
        for (m = rx_req->mb, i = 0; m != NULL; m = m->m_next, i++) {
                sge[i].addr = rx_req->mapping[i];
                sge[i].length = m->m_len;
        }

        wr->num_sge = i;
        wr->wr_id = id | IPOIB_OP_CM | IPOIB_OP_RECV;

        ret = ib_post_recv(rx->qp, wr, &bad_wr);
        if (unlikely(ret)) {
                ipoib_warn(priv, "post recv failed for buf %d (%d)\n", id, ret);
                ipoib_dma_unmap_rx(priv, rx_req);
                m_freem(rx->rx_ring[id].mb);
                rx->rx_ring[id].mb = NULL;
        }

        return ret;
}

static struct mbuf *
ipoib_cm_alloc_rx_mb(struct ipoib_dev_priv *priv, struct ipoib_cm_rx_buf *rx_req)
{
        return ipoib_alloc_map_mb(priv, (struct ipoib_rx_buf *)rx_req,
            sizeof(struct ipoib_pseudoheader), priv->cm.max_cm_mtu, IPOIB_CM_RX_SG);
}

static void ipoib_cm_free_rx_ring(struct ipoib_dev_priv *priv,
                                  struct ipoib_cm_rx_buf *rx_ring)
{
        int i;

        for (i = 0; i < ipoib_recvq_size; ++i)
                if (rx_ring[i].mb) {
                        ipoib_cm_dma_unmap_rx(priv, &rx_ring[i]);
                        m_freem(rx_ring[i].mb);
                }

        kfree(rx_ring);
}

static void ipoib_cm_start_rx_drain(struct ipoib_dev_priv *priv)
{
        const struct ib_send_wr *bad_wr;
        struct ipoib_cm_rx *p;

        /* We only reserved 1 extra slot in CQ for drain WRs, so
         * make sure we have at most 1 outstanding WR. */
        if (list_empty(&priv->cm.rx_flush_list) ||
            !list_empty(&priv->cm.rx_drain_list))
                return;

        /*
         * QPs on flush list are error state.  This way, a "flush
         * error" WC will be immediately generated for each WR we post.
         */
        p = list_entry(priv->cm.rx_flush_list.next, typeof(*p), list);
        if (ib_post_send(p->qp, &ipoib_cm_rx_drain_wr, &bad_wr))
                ipoib_warn(priv, "failed to post drain wr\n");

        list_splice_init(&priv->cm.rx_flush_list, &priv->cm.rx_drain_list);
}

static void ipoib_cm_rx_event_handler(struct ib_event *event, void *ctx)
{
        struct ipoib_cm_rx *p = ctx;
        struct ipoib_dev_priv *priv = p->priv;
        unsigned long flags;

        if (event->event != IB_EVENT_QP_LAST_WQE_REACHED)
                return;

        spin_lock_irqsave(&priv->lock, flags);
        list_move(&p->list, &priv->cm.rx_flush_list);
        p->state = IPOIB_CM_RX_FLUSH;
        ipoib_cm_start_rx_drain(priv);
        spin_unlock_irqrestore(&priv->lock, flags);
}

static struct ib_qp *ipoib_cm_create_rx_qp(struct ipoib_dev_priv *priv,
                                           struct ipoib_cm_rx *p)
{
        struct ib_qp_init_attr attr = {
                .event_handler = ipoib_cm_rx_event_handler,
                .send_cq = priv->recv_cq, /* For drain WR */
                .recv_cq = priv->recv_cq,
                .srq = priv->cm.srq,
                .cap.max_send_wr = 1, /* For drain WR */
                .cap.max_send_sge = 1,
                .sq_sig_type = IB_SIGNAL_ALL_WR,
                .qp_type = IB_QPT_RC,
                .qp_context = p,
        };

        if (!ipoib_cm_has_srq(priv)) {
                attr.cap.max_recv_wr  = ipoib_recvq_size;
                attr.cap.max_recv_sge = priv->cm.num_frags;
        }

        return ib_create_qp(priv->pd, &attr);
}

static int ipoib_cm_modify_rx_qp(struct ipoib_dev_priv *priv,
                                 struct ib_cm_id *cm_id, struct ib_qp *qp,
                                 unsigned psn)
{
        struct ib_qp_attr qp_attr;
        int qp_attr_mask, ret;

        qp_attr.qp_state = IB_QPS_INIT;
        ret = ib_cm_init_qp_attr(cm_id, &qp_attr, &qp_attr_mask);
        if (ret) {
                ipoib_warn(priv, "failed to init QP attr for INIT: %d\n", ret);
                return ret;
        }
        ret = ib_modify_qp(qp, &qp_attr, qp_attr_mask);
        if (ret) {
                ipoib_warn(priv, "failed to modify QP to INIT: %d\n", ret);
                return ret;
        }
        qp_attr.qp_state = IB_QPS_RTR;
        ret = ib_cm_init_qp_attr(cm_id, &qp_attr, &qp_attr_mask);
        if (ret) {
                ipoib_warn(priv, "failed to init QP attr for RTR: %d\n", ret);
                return ret;
        }
        qp_attr.rq_psn = psn;
        ret = ib_modify_qp(qp, &qp_attr, qp_attr_mask);
        if (ret) {
                ipoib_warn(priv, "failed to modify QP to RTR: %d\n", ret);
                return ret;
        }

        /*
         * Current Mellanox HCA firmware won't generate completions
         * with error for drain WRs unless the QP has been moved to
         * RTS first. This work-around leaves a window where a QP has
         * moved to error asynchronously, but this will eventually get
         * fixed in firmware, so let's not error out if modify QP
         * fails.
         */
        qp_attr.qp_state = IB_QPS_RTS;
        ret = ib_cm_init_qp_attr(cm_id, &qp_attr, &qp_attr_mask);
        if (ret) {
                ipoib_warn(priv, "failed to init QP attr for RTS: %d\n", ret);
                return 0;
        }
        ret = ib_modify_qp(qp, &qp_attr, qp_attr_mask);
        if (ret) {
                ipoib_warn(priv, "failed to modify QP to RTS: %d\n", ret);
                return 0;
        }

        return 0;
}

static void ipoib_cm_init_rx_wr(struct ipoib_dev_priv *priv,
                                struct ib_recv_wr *wr,
                                struct ib_sge *sge)
{
        int i;

        for (i = 0; i < IPOIB_CM_RX_SG; i++)
                sge[i].lkey = priv->pd->local_dma_lkey;

        wr->next    = NULL;
        wr->sg_list = sge;
        wr->num_sge = 1;
}

static int ipoib_cm_nonsrq_init_rx(struct ipoib_dev_priv *priv,
    struct ib_cm_id *cm_id, struct ipoib_cm_rx *rx)
{
        struct {
                struct ib_recv_wr wr;
                struct ib_sge sge[IPOIB_CM_RX_SG];
        } *t;
        int ret;
        int i;

        rx->rx_ring = kzalloc(ipoib_recvq_size * sizeof *rx->rx_ring, GFP_KERNEL);
        if (!rx->rx_ring) {
                printk(KERN_WARNING "%s: failed to allocate CM non-SRQ ring (%d entries)\n",
                       priv->ca->name, ipoib_recvq_size);
                return -ENOMEM;
        }

        memset(rx->rx_ring, 0, ipoib_recvq_size * sizeof *rx->rx_ring);

        t = kmalloc(sizeof *t, GFP_KERNEL);
        if (!t) {
                ret = -ENOMEM;
                goto err_free;
        }

        ipoib_cm_init_rx_wr(priv, &t->wr, t->sge);

        spin_lock_irq(&priv->lock);

        if (priv->cm.nonsrq_conn_qp >= ipoib_max_conn_qp) {
                spin_unlock_irq(&priv->lock);
                ib_send_cm_rej(cm_id, IB_CM_REJ_NO_QP, NULL, 0, NULL, 0);
                ret = -EINVAL;
                goto err_free;
        } else
                ++priv->cm.nonsrq_conn_qp;

        spin_unlock_irq(&priv->lock);

        for (i = 0; i < ipoib_recvq_size; ++i) {
                if (!ipoib_cm_alloc_rx_mb(priv, &rx->rx_ring[i])) {
                        ipoib_warn(priv, "failed to allocate receive buffer %d\n", i);
                                ret = -ENOMEM;
                                goto err_count;
                }
                ret = ipoib_cm_post_receive_nonsrq(priv, rx, &t->wr, t->sge, i);
                if (ret) {
                        ipoib_warn(priv, "ipoib_cm_post_receive_nonsrq "
                                   "failed for buf %d\n", i);
                        ret = -EIO;
                        goto err_count;
                }
        }

        rx->recv_count = ipoib_recvq_size;

        kfree(t);

        return 0;

err_count:
        spin_lock_irq(&priv->lock);
        --priv->cm.nonsrq_conn_qp;
        spin_unlock_irq(&priv->lock);

err_free:
        kfree(t);
        ipoib_cm_free_rx_ring(priv, rx->rx_ring);

        return ret;
}

static int ipoib_cm_send_rep(struct ipoib_dev_priv *priv, struct ib_cm_id *cm_id,
                             struct ib_qp *qp, struct ib_cm_req_event_param *req,
                             unsigned psn)
{
        struct ipoib_cm_data data = {};
        struct ib_cm_rep_param rep = {};

        data.qpn = cpu_to_be32(priv->qp->qp_num);
        data.mtu = cpu_to_be32(priv->cm.max_cm_mtu);

        rep.private_data = &data;
        rep.private_data_len = sizeof data;
        rep.flow_control = 0;
        rep.rnr_retry_count = req->rnr_retry_count;
        rep.srq = ipoib_cm_has_srq(priv);
        rep.qp_num = qp->qp_num;
        rep.starting_psn = psn;
        return ib_send_cm_rep(cm_id, &rep);
}

static int ipoib_cm_req_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event)
{
        struct ipoib_dev_priv *priv = cm_id->context;
        struct ipoib_cm_rx *p;
        unsigned psn;
        int ret;

        ipoib_dbg(priv, "REQ arrived\n");
        p = kzalloc(sizeof *p, GFP_KERNEL);
        if (!p)
                return -ENOMEM;
        p->priv = priv;
        p->id = cm_id;
        cm_id->context = p;
        p->state = IPOIB_CM_RX_LIVE;
        p->jiffies = jiffies;
        INIT_LIST_HEAD(&p->list);

        p->qp = ipoib_cm_create_rx_qp(priv, p);
        if (IS_ERR(p->qp)) {
                ret = PTR_ERR(p->qp);
                goto err_qp;
        }

        psn = random() & 0xffffff;
        ret = ipoib_cm_modify_rx_qp(priv, cm_id, p->qp, psn);
        if (ret)
                goto err_modify;

        if (!ipoib_cm_has_srq(priv)) {
                ret = ipoib_cm_nonsrq_init_rx(priv, cm_id, p);
                if (ret)
                        goto err_modify;
        }

        spin_lock_irq(&priv->lock);
        queue_delayed_work(ipoib_workqueue,
                           &priv->cm.stale_task, IPOIB_CM_RX_DELAY);
        /* Add this entry to passive ids list head, but do not re-add it
         * if IB_EVENT_QP_LAST_WQE_REACHED has moved it to flush list. */
        p->jiffies = jiffies;
        if (p->state == IPOIB_CM_RX_LIVE)
                list_move(&p->list, &priv->cm.passive_ids);
        spin_unlock_irq(&priv->lock);

        ret = ipoib_cm_send_rep(priv, cm_id, p->qp, &event->param.req_rcvd, psn);
        if (ret) {
                ipoib_warn(priv, "failed to send REP: %d\n", ret);
                if (ib_modify_qp(p->qp, &ipoib_cm_err_attr, IB_QP_STATE))
                        ipoib_warn(priv, "unable to move qp to error state\n");
        }
        return 0;

err_modify:
        ib_destroy_qp(p->qp);
err_qp:
        kfree(p);
        return ret;
}

static int ipoib_cm_rx_handler(struct ib_cm_id *cm_id,
                               struct ib_cm_event *event)
{
        struct ipoib_cm_rx *p;
        struct ipoib_dev_priv *priv;

        switch (event->event) {
        case IB_CM_REQ_RECEIVED:
                return ipoib_cm_req_handler(cm_id, event);
        case IB_CM_DREQ_RECEIVED:
                p = cm_id->context;
                ib_send_cm_drep(cm_id, NULL, 0);
                /* Fall through */
        case IB_CM_REJ_RECEIVED:
                p = cm_id->context;
                priv = p->priv;
                if (ib_modify_qp(p->qp, &ipoib_cm_err_attr, IB_QP_STATE))
                        ipoib_warn(priv, "unable to move qp to error state\n");
                /* Fall through */
        default:
                return 0;
        }
}

void ipoib_cm_handle_rx_wc(struct ipoib_dev_priv *priv, struct ib_wc *wc)
{
        struct ipoib_cm_rx_buf saverx;
        struct ipoib_cm_rx_buf *rx_ring;
        unsigned int wr_id = wc->wr_id & ~(IPOIB_OP_CM | IPOIB_OP_RECV);
        if_t dev = priv->dev;
        struct mbuf *mb, *newmb;
        struct ipoib_cm_rx *p;
        int has_srq;

        ipoib_dbg_data(priv, "cm recv completion: id %d, status: %d\n",
                       wr_id, wc->status);

        if (unlikely(wr_id >= ipoib_recvq_size)) {
                if (wr_id == (IPOIB_CM_RX_DRAIN_WRID & ~(IPOIB_OP_CM | IPOIB_OP_RECV))) {
                        spin_lock(&priv->lock);
                        list_splice_init(&priv->cm.rx_drain_list, &priv->cm.rx_reap_list);
                        ipoib_cm_start_rx_drain(priv);
                        if (priv->cm.id != NULL)
                                queue_work(ipoib_workqueue,
                                    &priv->cm.rx_reap_task);
                        spin_unlock(&priv->lock);
                } else
                        ipoib_warn(priv, "cm recv completion event with wrid %d (> %d)\n",
                                   wr_id, ipoib_recvq_size);
                goto done;
        }

        p = wc->qp->qp_context;

        has_srq = ipoib_cm_has_srq(priv);
        rx_ring = has_srq ? priv->cm.srq_ring : p->rx_ring;

        mb = rx_ring[wr_id].mb;

        if (unlikely(wc->status != IB_WC_SUCCESS)) {
                ipoib_dbg(priv, "cm recv error "
                           "(status=%d, wrid=%d vend_err %x)\n",
                           wc->status, wr_id, wc->vendor_err);
                if_inc_counter(dev, IFCOUNTER_IERRORS, 1);
                if (has_srq)
                        goto repost;
                else {
                        if (!--p->recv_count) {
                                spin_lock(&priv->lock);
                                list_move(&p->list, &priv->cm.rx_reap_list);
                                queue_work(ipoib_workqueue, &priv->cm.rx_reap_task);
                                spin_unlock(&priv->lock);
                        }
                        goto done;
                }
        }

        if (unlikely(!(wr_id & IPOIB_CM_RX_UPDATE_MASK))) {
                if (p && time_after_eq(jiffies, p->jiffies + IPOIB_CM_RX_UPDATE_TIME)) {
                        p->jiffies = jiffies;
                        /* Move this entry to list head, but do not re-add it
                         * if it has been moved out of list. */
                        if (p->state == IPOIB_CM_RX_LIVE)
                                list_move(&p->list, &priv->cm.passive_ids);
                }
        }

        memcpy(&saverx, &rx_ring[wr_id], sizeof(saverx));
        newmb = ipoib_cm_alloc_rx_mb(priv, &rx_ring[wr_id]);
        if (unlikely(!newmb)) {
                /*
                 * If we can't allocate a new RX buffer, dump
                 * this packet and reuse the old buffer.
                 */
                ipoib_dbg(priv, "failed to allocate receive buffer %d\n", wr_id);
                if_inc_counter(dev, IFCOUNTER_IERRORS, 1);
                memcpy(&rx_ring[wr_id], &saverx, sizeof(saverx));
                goto repost;
        }

        ipoib_cm_dma_unmap_rx(priv, &saverx);

        ipoib_dbg_data(priv, "received %d bytes, SLID 0x%04x\n",
                       wc->byte_len, wc->slid);

        ipoib_dma_mb(priv, mb, wc->byte_len);

        mb->m_pkthdr.rcvif = dev;

        M_PREPEND(mb, sizeof(struct ipoib_pseudoheader), M_NOWAIT);
        if (likely(mb != NULL)) {
                struct ipoib_header *ibh;

                if_inc_counter(dev, IFCOUNTER_IPACKETS, 1);
                if_inc_counter(dev, IFCOUNTER_IBYTES, mb->m_pkthdr.len);

                /* fixup destination infiniband address */
                ibh = mtod(mb, struct ipoib_header *);
                memset(ibh->hwaddr, 0, 4);
                memcpy(ibh->hwaddr + 4, priv->local_gid.raw, sizeof(union ib_gid));

                if_input(dev, mb);
        } else {
                if_inc_counter(dev, IFCOUNTER_IERRORS, 1);
        }
repost:
        if (has_srq) {
                if (unlikely(ipoib_cm_post_receive_srq(priv, wr_id)))
                        ipoib_warn(priv, "ipoib_cm_post_receive_srq failed "
                                   "for buf %d\n", wr_id);
        } else {
                if (unlikely(ipoib_cm_post_receive_nonsrq(priv, p,
                                                          &priv->cm.rx_wr,
                                                          priv->cm.rx_sge,
                                                          wr_id))) {
                        --p->recv_count;
                        ipoib_warn(priv, "ipoib_cm_post_receive_nonsrq failed "
                                   "for buf %d\n", wr_id);
                }
        }
done:
        return;
}

static inline int post_send(struct ipoib_dev_priv *priv,
                            struct ipoib_cm_tx *tx,
                            struct ipoib_cm_tx_buf *tx_req,
                            unsigned int wr_id)
{
        const struct ib_send_wr *bad_wr;
        struct mbuf *mb = tx_req->mb;
        u64 *mapping = tx_req->mapping;
        struct mbuf *m;
        int i;

        for (m = mb, i = 0; m != NULL; m = m->m_next, i++) {
                priv->tx_sge[i].addr = mapping[i];
                priv->tx_sge[i].length = m->m_len;
        }
        priv->tx_wr.wr.num_sge = i;
        priv->tx_wr.wr.wr_id = wr_id | IPOIB_OP_CM;
        priv->tx_wr.wr.opcode = IB_WR_SEND;

        return ib_post_send(tx->qp, &priv->tx_wr.wr, &bad_wr);
}

void ipoib_cm_send(struct ipoib_dev_priv *priv, struct mbuf *mb, struct ipoib_cm_tx *tx)
{
        struct ipoib_cm_tx_buf *tx_req;
        if_t dev = priv->dev;

        if (unlikely(priv->tx_outstanding > MAX_SEND_CQE)) {
                while (ipoib_poll_tx(priv, false))
                        ;       /* nothing */
        }

        m_adj(mb, sizeof(struct ipoib_pseudoheader));
        if (unlikely(mb->m_pkthdr.len > tx->mtu)) {
                ipoib_warn(priv, "packet len %d (> %d) too long to send, dropping\n",
                           mb->m_pkthdr.len, tx->mtu);
                if_inc_counter(dev, IFCOUNTER_OERRORS, 1);
                ipoib_cm_mb_too_long(priv, mb, IPOIB_CM_MTU(tx->mtu));
                return;
        }

        ipoib_dbg_data(priv, "sending packet: head 0x%x length %d connection 0x%x\n",
                       tx->tx_head, mb->m_pkthdr.len, tx->qp->qp_num);


        /*
         * We put the mb into the tx_ring _before_ we call post_send()
         * because it's entirely possible that the completion handler will
         * run before we execute anything after the post_send().  That
         * means we have to make sure everything is properly recorded and
         * our state is consistent before we call post_send().
         */
        tx_req = &tx->tx_ring[tx->tx_head & (ipoib_sendq_size - 1)];
        tx_req->mb = mb;
        if (unlikely(ipoib_dma_map_tx(priv->ca, (struct ipoib_tx_buf *)tx_req,
            priv->cm.num_frags))) {
                if_inc_counter(dev, IFCOUNTER_OERRORS, 1);
                if (tx_req->mb)
                        m_freem(tx_req->mb);
                return;
        }

        if (unlikely(post_send(priv, tx, tx_req, tx->tx_head & (ipoib_sendq_size - 1)))) {
                ipoib_warn(priv, "post_send failed\n");
                if_inc_counter(dev, IFCOUNTER_OERRORS, 1);
                ipoib_dma_unmap_tx(priv->ca, (struct ipoib_tx_buf *)tx_req);
                m_freem(mb);
        } else {
                ++tx->tx_head;

                if (++priv->tx_outstanding == ipoib_sendq_size) {
                        ipoib_dbg(priv, "TX ring 0x%x full, stopping kernel net queue\n",
                                  tx->qp->qp_num);
                        if (ib_req_notify_cq(priv->send_cq, IB_CQ_NEXT_COMP))
                                ipoib_warn(priv, "request notify on send CQ failed\n");
                        if_setdrvflagbits(dev, IFF_DRV_OACTIVE, 0);
                }
        }

}

void ipoib_cm_handle_tx_wc(struct ipoib_dev_priv *priv, struct ib_wc *wc)
{
        struct ipoib_cm_tx *tx = wc->qp->qp_context;
        unsigned int wr_id = wc->wr_id & ~IPOIB_OP_CM;
        if_t dev = priv->dev;
        struct ipoib_cm_tx_buf *tx_req;

        ipoib_dbg_data(priv, "cm send completion: id %d, status: %d\n",
                       wr_id, wc->status);

        if (unlikely(wr_id >= ipoib_sendq_size)) {
                ipoib_warn(priv, "cm send completion event with wrid %d (> %d)\n",
                           wr_id, ipoib_sendq_size);
                return;
        }

        tx_req = &tx->tx_ring[wr_id];

        ipoib_dma_unmap_tx(priv->ca, (struct ipoib_tx_buf *)tx_req);

        /* FIXME: is this right? Shouldn't we only increment on success? */
        if_inc_counter(dev, IFCOUNTER_OPACKETS, 1);

        m_freem(tx_req->mb);

        ++tx->tx_tail;
        if (unlikely(--priv->tx_outstanding == ipoib_sendq_size >> 1) &&
            (if_getdrvflags(dev) & IFF_DRV_OACTIVE) != 0 &&
            test_bit(IPOIB_FLAG_ADMIN_UP, &priv->flags))
                if_setdrvflagbits(dev, 0, IFF_DRV_OACTIVE);

        if (wc->status != IB_WC_SUCCESS &&
            wc->status != IB_WC_WR_FLUSH_ERR) {
                struct ipoib_path *path;

                ipoib_dbg(priv, "failed cm send event "
                           "(status=%d, wrid=%d vend_err %x)\n",
                           wc->status, wr_id, wc->vendor_err);

                path = tx->path;

                if (path) {
                        path->cm = NULL;
                        rb_erase(&path->rb_node, &priv->path_tree);
                        list_del(&path->list);
                }

                if (test_and_clear_bit(IPOIB_FLAG_INITIALIZED, &tx->flags)) {
                        list_move(&tx->list, &priv->cm.reap_list);
                        queue_work(ipoib_workqueue, &priv->cm.reap_task);
                }

                clear_bit(IPOIB_FLAG_OPER_UP, &tx->flags);
        }

}

int ipoib_cm_dev_open(struct ipoib_dev_priv *priv)
{
        int ret;

        if (!IPOIB_CM_SUPPORTED(if_getlladdr(priv->dev)))
                return 0;

        priv->cm.id = ib_create_cm_id(priv->ca, ipoib_cm_rx_handler, priv);
        if (IS_ERR(priv->cm.id)) {
                printk(KERN_WARNING "%s: failed to create CM ID\n", priv->ca->name);
                ret = PTR_ERR(priv->cm.id);
                goto err_cm;
        }

        ret = ib_cm_listen(priv->cm.id, cpu_to_be64(IPOIB_CM_IETF_ID | priv->qp->qp_num), 0);
        if (ret) {
                printk(KERN_WARNING "%s: failed to listen on ID 0x%llx\n", priv->ca->name,
                       IPOIB_CM_IETF_ID | priv->qp->qp_num);
                goto err_listen;
        }

        return 0;

err_listen:
        ib_destroy_cm_id(priv->cm.id);
err_cm:
        priv->cm.id = NULL;
        return ret;
}

static void ipoib_cm_free_rx_reap_list(struct ipoib_dev_priv *priv)
{
        struct ipoib_cm_rx *rx, *n;
        LIST_HEAD(list);

        spin_lock_irq(&priv->lock);
        list_splice_init(&priv->cm.rx_reap_list, &list);
        spin_unlock_irq(&priv->lock);

        list_for_each_entry_safe(rx, n, &list, list) {
                ib_destroy_cm_id(rx->id);
                ib_destroy_qp(rx->qp);
                if (!ipoib_cm_has_srq(priv)) {
                        ipoib_cm_free_rx_ring(priv, rx->rx_ring);
                        spin_lock_irq(&priv->lock);
                        --priv->cm.nonsrq_conn_qp;
                        spin_unlock_irq(&priv->lock);
                }
                kfree(rx);
        }
}

void ipoib_cm_dev_stop(struct ipoib_dev_priv *priv)
{
        struct ipoib_cm_rx *p;
        unsigned long begin;
        int ret;

        if (!IPOIB_CM_SUPPORTED(if_getlladdr(priv->dev)) || !priv->cm.id)
                return;

        ib_destroy_cm_id(priv->cm.id);
        priv->cm.id = NULL;

        cancel_work_sync(&priv->cm.rx_reap_task);

        spin_lock_irq(&priv->lock);
        while (!list_empty(&priv->cm.passive_ids)) {
                p = list_entry(priv->cm.passive_ids.next, typeof(*p), list);
                list_move(&p->list, &priv->cm.rx_error_list);
                p->state = IPOIB_CM_RX_ERROR;
                spin_unlock_irq(&priv->lock);
                ret = ib_modify_qp(p->qp, &ipoib_cm_err_attr, IB_QP_STATE);
                if (ret)
                        ipoib_warn(priv, "unable to move qp to error state: %d\n", ret);
                spin_lock_irq(&priv->lock);
        }

        /* Wait for all RX to be drained */
        begin = jiffies;

        while (!list_empty(&priv->cm.rx_error_list) ||
               !list_empty(&priv->cm.rx_flush_list) ||
               !list_empty(&priv->cm.rx_drain_list)) {
                if (time_after(jiffies, begin + 5 * HZ)) {
                        ipoib_warn(priv, "RX drain timing out\n");

                        /*
                         * assume the HW is wedged and just free up everything.
                         */
                        list_splice_init(&priv->cm.rx_flush_list,
                                         &priv->cm.rx_reap_list);
                        list_splice_init(&priv->cm.rx_error_list,
                                         &priv->cm.rx_reap_list);
                        list_splice_init(&priv->cm.rx_drain_list,
                                         &priv->cm.rx_reap_list);
                        break;
                }
                spin_unlock_irq(&priv->lock);
                msleep(1);
                ipoib_drain_cq(priv);
                spin_lock_irq(&priv->lock);
        }

        spin_unlock_irq(&priv->lock);

        ipoib_cm_free_rx_reap_list(priv);

        cancel_delayed_work_sync(&priv->cm.stale_task);
}

static int ipoib_cm_rep_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event)
{
        struct ipoib_cm_tx *p = cm_id->context;
        struct ipoib_dev_priv *priv = p->priv;
        struct ipoib_cm_data *data = event->private_data;
        struct epoch_tracker et;
        struct ifqueue mbqueue;
        struct ib_qp_attr qp_attr;
        int qp_attr_mask, ret;
        struct mbuf *mb;

        ipoib_dbg(priv, "cm rep handler\n");
        p->mtu = be32_to_cpu(data->mtu);

        if (p->mtu <= IPOIB_ENCAP_LEN) {
                ipoib_warn(priv, "Rejecting connection: mtu %d <= %d\n",
                           p->mtu, IPOIB_ENCAP_LEN);
                return -EINVAL;
        }

        qp_attr.qp_state = IB_QPS_RTR;
        ret = ib_cm_init_qp_attr(cm_id, &qp_attr, &qp_attr_mask);
        if (ret) {
                ipoib_warn(priv, "failed to init QP attr for RTR: %d\n", ret);
                return ret;
        }

        qp_attr.rq_psn = 0 /* FIXME */;
        ret = ib_modify_qp(p->qp, &qp_attr, qp_attr_mask);
        if (ret) {
                ipoib_warn(priv, "failed to modify QP to RTR: %d\n", ret);
                return ret;
        }

        qp_attr.qp_state = IB_QPS_RTS;
        ret = ib_cm_init_qp_attr(cm_id, &qp_attr, &qp_attr_mask);
        if (ret) {
                ipoib_warn(priv, "failed to init QP attr for RTS: %d\n", ret);
                return ret;
        }
        ret = ib_modify_qp(p->qp, &qp_attr, qp_attr_mask);
        if (ret) {
                ipoib_warn(priv, "failed to modify QP to RTS: %d\n", ret);
                return ret;
        }

        bzero(&mbqueue, sizeof(mbqueue));

        spin_lock_irq(&priv->lock);
        set_bit(IPOIB_FLAG_OPER_UP, &p->flags);
        if (p->path)
                for (;;) {
                        _IF_DEQUEUE(&p->path->queue, mb);
                        if (mb == NULL)
                                break;
                        _IF_ENQUEUE(&mbqueue, mb);
                }
        spin_unlock_irq(&priv->lock);

        NET_EPOCH_ENTER(et);
        for (;;) {
                if_t dev = p->priv->dev;
                _IF_DEQUEUE(&mbqueue, mb);
                if (mb == NULL)
                        break;
                mb->m_pkthdr.rcvif = dev;
                if (if_transmit(dev, mb))
                        ipoib_warn(priv, "dev_queue_xmit failed "
                                   "to requeue packet\n");
        }
        NET_EPOCH_EXIT(et);

        ret = ib_send_cm_rtu(cm_id, NULL, 0);
        if (ret) {
                ipoib_warn(priv, "failed to send RTU: %d\n", ret);
                return ret;
        }
        return 0;
}

static struct ib_qp *ipoib_cm_create_tx_qp(struct ipoib_dev_priv *priv,
    struct ipoib_cm_tx *tx)
{
        struct ib_qp_init_attr attr = {
                .send_cq                = priv->send_cq,
                .recv_cq                = priv->recv_cq,
                .srq                    = priv->cm.srq,
                .cap.max_send_wr        = ipoib_sendq_size,
                .cap.max_send_sge       = priv->cm.num_frags,
                .sq_sig_type            = IB_SIGNAL_ALL_WR,
                .qp_type                = IB_QPT_RC,
                .qp_context             = tx
        };

        return ib_create_qp(priv->pd, &attr);
}

static int ipoib_cm_send_req(struct ipoib_dev_priv *priv,
                             struct ib_cm_id *id, struct ib_qp *qp,
                             u32 qpn,
                             struct ib_sa_path_rec *pathrec)
{
        struct ipoib_cm_data data = {};
        struct ib_cm_req_param req = {};

        ipoib_dbg(priv, "cm send req\n");

        data.qpn = cpu_to_be32(priv->qp->qp_num);
        data.mtu = cpu_to_be32(priv->cm.max_cm_mtu);

        req.primary_path                = pathrec;
        req.alternate_path              = NULL;
        req.service_id                  = cpu_to_be64(IPOIB_CM_IETF_ID | qpn);
        req.qp_num                      = qp->qp_num;
        req.qp_type                     = qp->qp_type;
        req.private_data                = &data;
        req.private_data_len            = sizeof data;
        req.flow_control                = 0;

        req.starting_psn                = 0; /* FIXME */

        /*
         * Pick some arbitrary defaults here; we could make these
         * module parameters if anyone cared about setting them.
         */
        req.responder_resources         = 4;
        req.remote_cm_response_timeout  = 20;
        req.local_cm_response_timeout   = 20;
        req.retry_count                 = 0; /* RFC draft warns against retries */
        req.rnr_retry_count             = 0; /* RFC draft warns against retries */
        req.max_cm_retries              = 15;
        req.srq                         = ipoib_cm_has_srq(priv);
        return ib_send_cm_req(id, &req);
}

static int ipoib_cm_modify_tx_init(struct ipoib_dev_priv *priv,
                                  struct ib_cm_id *cm_id, struct ib_qp *qp)
{
        struct ib_qp_attr qp_attr;
        int qp_attr_mask, ret;
        ret = ib_find_pkey(priv->ca, priv->port, priv->pkey, &qp_attr.pkey_index);
        if (ret) {
                ipoib_warn(priv, "pkey 0x%x not found: %d\n", priv->pkey, ret);
                return ret;
        }

        qp_attr.qp_state = IB_QPS_INIT;
        qp_attr.qp_access_flags = IB_ACCESS_LOCAL_WRITE;
        qp_attr.port_num = priv->port;
        qp_attr_mask = IB_QP_STATE | IB_QP_ACCESS_FLAGS | IB_QP_PKEY_INDEX | IB_QP_PORT;

        ret = ib_modify_qp(qp, &qp_attr, qp_attr_mask);
        if (ret) {
                ipoib_warn(priv, "failed to modify tx QP to INIT: %d\n", ret);
                return ret;
        }
        return 0;
}

static int ipoib_cm_tx_init(struct ipoib_cm_tx *p, u32 qpn,
                            struct ib_sa_path_rec *pathrec)
{
        struct ipoib_dev_priv *priv = p->priv;
        int ret;

        p->tx_ring = kzalloc(ipoib_sendq_size * sizeof *p->tx_ring, GFP_KERNEL);
        if (!p->tx_ring) {
                ipoib_warn(priv, "failed to allocate tx ring\n");
                ret = -ENOMEM;
                goto err_tx;
        }
        memset(p->tx_ring, 0, ipoib_sendq_size * sizeof *p->tx_ring);

        p->qp = ipoib_cm_create_tx_qp(p->priv, p);
        if (IS_ERR(p->qp)) {
                ret = PTR_ERR(p->qp);
                ipoib_warn(priv, "failed to allocate tx qp: %d\n", ret);
                goto err_qp;
        }

        p->id = ib_create_cm_id(priv->ca, ipoib_cm_tx_handler, p);
        if (IS_ERR(p->id)) {
                ret = PTR_ERR(p->id);
                ipoib_warn(priv, "failed to create tx cm id: %d\n", ret);
                goto err_id;
        }

        ret = ipoib_cm_modify_tx_init(p->priv, p->id,  p->qp);
        if (ret) {
                ipoib_warn(priv, "failed to modify tx qp to rtr: %d\n", ret);
                goto err_modify;
        }

        ret = ipoib_cm_send_req(p->priv, p->id, p->qp, qpn, pathrec);
        if (ret) {
                ipoib_warn(priv, "failed to send cm req: %d\n", ret);
                goto err_send_cm;
        }

        ipoib_dbg(priv, "Request connection 0x%x for gid %pI6 qpn 0x%x\n",
                  p->qp->qp_num, pathrec->dgid.raw, qpn);

        return 0;

err_send_cm:
err_modify:
        ib_destroy_cm_id(p->id);
err_id:
        p->id = NULL;
        ib_destroy_qp(p->qp);
err_qp:
        p->qp = NULL;
        kfree(p->tx_ring);
err_tx:
        return ret;
}

static void ipoib_cm_tx_destroy(struct ipoib_cm_tx *p)
{
        struct ipoib_dev_priv *priv = p->priv;
        if_t dev = priv->dev;
        struct ipoib_cm_tx_buf *tx_req;
        unsigned long begin;

        ipoib_dbg(priv, "Destroy active connection 0x%x head 0x%x tail 0x%x\n",
                  p->qp ? p->qp->qp_num : 0, p->tx_head, p->tx_tail);

        if (p->path)
                ipoib_path_free(priv, p->path);

        if (p->id)
                ib_destroy_cm_id(p->id);

        if (p->tx_ring) {
                /* Wait for all sends to complete */
                begin = jiffies;
                while ((int) p->tx_tail - (int) p->tx_head < 0) {
                        if (time_after(jiffies, begin + 5 * HZ)) {
                                ipoib_warn(priv, "timing out; %d sends not completed\n",
                                           p->tx_head - p->tx_tail);
                                goto timeout;
                        }

                        msleep(1);
                }
        }

timeout:

        while ((int) p->tx_tail - (int) p->tx_head < 0) {
                tx_req = &p->tx_ring[p->tx_tail & (ipoib_sendq_size - 1)];
                ipoib_dma_unmap_tx(priv->ca, (struct ipoib_tx_buf *)tx_req);
                m_freem(tx_req->mb);
                ++p->tx_tail;
                if (unlikely(--priv->tx_outstanding == ipoib_sendq_size >> 1) &&
                    (if_getdrvflags(dev) & IFF_DRV_OACTIVE) != 0 &&
                    test_bit(IPOIB_FLAG_ADMIN_UP, &priv->flags))
                        if_setdrvflagbits(dev, 0, IFF_DRV_OACTIVE);
        }

        if (p->qp)
                ib_destroy_qp(p->qp);

        kfree(p->tx_ring);
        kfree(p);
}

static int ipoib_cm_tx_handler(struct ib_cm_id *cm_id,
                               struct ib_cm_event *event)
{
        struct ipoib_cm_tx *tx = cm_id->context;
        struct ipoib_dev_priv *priv = tx->priv;
        struct ipoib_path *path;
        unsigned long flags;
        int ret;

        switch (event->event) {
        case IB_CM_DREQ_RECEIVED:
                ipoib_dbg(priv, "DREQ received.\n");
                ib_send_cm_drep(cm_id, NULL, 0);
                break;
        case IB_CM_REP_RECEIVED:
                ipoib_dbg(priv, "REP received.\n");
                ret = ipoib_cm_rep_handler(cm_id, event);
                if (ret)
                        ib_send_cm_rej(cm_id, IB_CM_REJ_CONSUMER_DEFINED,
                                       NULL, 0, NULL, 0);
                break;
        case IB_CM_REQ_ERROR:
        case IB_CM_REJ_RECEIVED:
        case IB_CM_TIMEWAIT_EXIT:
                ipoib_dbg(priv, "CM error %d.\n", event->event);
                spin_lock_irqsave(&priv->lock, flags);
                path = tx->path;

                if (path) {
                        path->cm = NULL;
                        tx->path = NULL;
                        rb_erase(&path->rb_node, &priv->path_tree);
                        list_del(&path->list);
                }

                if (test_and_clear_bit(IPOIB_FLAG_INITIALIZED, &tx->flags)) {
                        list_move(&tx->list, &priv->cm.reap_list);
                        queue_work(ipoib_workqueue, &priv->cm.reap_task);
                }

                spin_unlock_irqrestore(&priv->lock, flags);
                if (path)
                        ipoib_path_free(tx->priv, path);
                break;
        default:
                break;
        }

        return 0;
}

struct ipoib_cm_tx *ipoib_cm_create_tx(struct ipoib_dev_priv *priv,
    struct ipoib_path *path)
{
        struct ipoib_cm_tx *tx;

        tx = kzalloc(sizeof *tx, GFP_ATOMIC);
        if (!tx)
                return NULL;

        ipoib_dbg(priv, "Creating cm tx\n");
        path->cm = tx;
        tx->path = path;
        tx->priv = priv;
        list_add(&tx->list, &priv->cm.start_list);
        set_bit(IPOIB_FLAG_INITIALIZED, &tx->flags);
        queue_work(ipoib_workqueue, &priv->cm.start_task);
        return tx;
}

void ipoib_cm_destroy_tx(struct ipoib_cm_tx *tx)
{
        struct ipoib_dev_priv *priv = tx->priv;
        if (test_and_clear_bit(IPOIB_FLAG_INITIALIZED, &tx->flags)) {
                spin_lock(&priv->lock);
                list_move(&tx->list, &priv->cm.reap_list);
                spin_unlock(&priv->lock);
                queue_work(ipoib_workqueue, &priv->cm.reap_task);
                ipoib_dbg(priv, "Reap connection for gid %pI6\n",
                          tx->path->pathrec.dgid.raw);
                tx->path = NULL;
        }
}

static void ipoib_cm_tx_start(struct work_struct *work)
{
        struct ipoib_dev_priv *priv = container_of(work, struct ipoib_dev_priv,
                                                   cm.start_task);
        struct ipoib_path *path;
        struct ipoib_cm_tx *p;
        unsigned long flags;
        int ret;

        struct ib_sa_path_rec pathrec;
        u32 qpn;

        ipoib_dbg(priv, "cm start task\n");
        spin_lock_irqsave(&priv->lock, flags);

        while (!list_empty(&priv->cm.start_list)) {
                p = list_entry(priv->cm.start_list.next, typeof(*p), list);
                list_del_init(&p->list);
                path = p->path;
                qpn = IPOIB_QPN(path->hwaddr);
                memcpy(&pathrec, &p->path->pathrec, sizeof pathrec);

                spin_unlock_irqrestore(&priv->lock, flags);

                ret = ipoib_cm_tx_init(p, qpn, &pathrec);

                spin_lock_irqsave(&priv->lock, flags);

                if (ret) {
                        path = p->path;
                        if (path) {
                                path->cm = NULL;
                                rb_erase(&path->rb_node, &priv->path_tree);
                                list_del(&path->list);
                                ipoib_path_free(priv, path);
                        }
                        list_del(&p->list);
                        kfree(p);
                }
        }

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

static void ipoib_cm_tx_reap(struct work_struct *work)
{
        struct ipoib_dev_priv *priv = container_of(work, struct ipoib_dev_priv,
                                                   cm.reap_task);
        struct ipoib_cm_tx *p;
        unsigned long flags;

        spin_lock_irqsave(&priv->lock, flags);

        while (!list_empty(&priv->cm.reap_list)) {
                p = list_entry(priv->cm.reap_list.next, typeof(*p), list);
                list_del(&p->list);
                spin_unlock_irqrestore(&priv->lock, flags);
                ipoib_cm_tx_destroy(p);
                spin_lock_irqsave(&priv->lock, flags);
        }

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

static void ipoib_cm_mb_reap(struct work_struct *work)
{
        struct ipoib_dev_priv *priv = container_of(work, struct ipoib_dev_priv,
                                                   cm.mb_task);
        struct mbuf *mb;
        unsigned long flags;
#if defined(INET) || defined(INET6)
        unsigned mtu = priv->mcast_mtu;
#endif
        uint16_t proto;

        spin_lock_irqsave(&priv->lock, flags);

        CURVNET_SET_QUIET(if_getvnet(priv->dev));

        for (;;) {
                IF_DEQUEUE(&priv->cm.mb_queue, mb);
                if (mb == NULL)
                        break;
                spin_unlock_irqrestore(&priv->lock, flags);

                proto = htons(*mtod(mb, uint16_t *));
                m_adj(mb, IPOIB_ENCAP_LEN);
                switch (proto) {
#if defined(INET)
                case ETHERTYPE_IP:
                        icmp_error(mb, ICMP_UNREACH, ICMP_UNREACH_NEEDFRAG, 0, mtu);
                        break;
#endif
#if defined(INET6)
                case ETHERTYPE_IPV6:
                        icmp6_error(mb, ICMP6_PACKET_TOO_BIG, 0, mtu);
                        break;
#endif
                default:
                        m_freem(mb);
                }

                spin_lock_irqsave(&priv->lock, flags);
        }

        CURVNET_RESTORE();

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

void
ipoib_cm_mb_too_long(struct ipoib_dev_priv *priv, struct mbuf *mb, unsigned int mtu)
{
        int e = priv->cm.mb_queue.ifq_len; 

        IF_ENQUEUE(&priv->cm.mb_queue, mb);
        if (e == 0)
                queue_work(ipoib_workqueue, &priv->cm.mb_task);
}

static void ipoib_cm_rx_reap(struct work_struct *work)
{
        ipoib_cm_free_rx_reap_list(container_of(work, struct ipoib_dev_priv,
                                                cm.rx_reap_task));
}

static void ipoib_cm_stale_task(struct work_struct *work)
{
        struct ipoib_dev_priv *priv = container_of(work, struct ipoib_dev_priv,
                                                   cm.stale_task.work);
        struct ipoib_cm_rx *p;
        int ret;

        spin_lock_irq(&priv->lock);
        while (!list_empty(&priv->cm.passive_ids)) {
                /* List is sorted by LRU, start from tail,
                 * stop when we see a recently used entry */
                p = list_entry(priv->cm.passive_ids.prev, typeof(*p), list);
                if (time_before_eq(jiffies, p->jiffies + IPOIB_CM_RX_TIMEOUT))
                        break;
                list_move(&p->list, &priv->cm.rx_error_list);
                p->state = IPOIB_CM_RX_ERROR;
                spin_unlock_irq(&priv->lock);
                ret = ib_modify_qp(p->qp, &ipoib_cm_err_attr, IB_QP_STATE);
                if (ret)
                        ipoib_warn(priv, "unable to move qp to error state: %d\n", ret);
                spin_lock_irq(&priv->lock);
        }

        if (!list_empty(&priv->cm.passive_ids))
                queue_delayed_work(ipoib_workqueue,
                                   &priv->cm.stale_task, IPOIB_CM_RX_DELAY);
        spin_unlock_irq(&priv->lock);
}


static void ipoib_cm_create_srq(struct ipoib_dev_priv *priv, int max_sge)
{
        struct ib_srq_init_attr srq_init_attr = {
                .attr = {
                        .max_wr  = ipoib_recvq_size,
                        .max_sge = max_sge
                }
        };

        priv->cm.srq = ib_create_srq(priv->pd, &srq_init_attr);
        if (IS_ERR(priv->cm.srq)) {
                if (PTR_ERR(priv->cm.srq) != -ENOSYS)
                        printk(KERN_WARNING "%s: failed to allocate SRQ, error %ld\n",
                               priv->ca->name, PTR_ERR(priv->cm.srq));
                priv->cm.srq = NULL;
                return;
        }

        priv->cm.srq_ring = kzalloc(ipoib_recvq_size * sizeof *priv->cm.srq_ring, GFP_KERNEL);
        if (!priv->cm.srq_ring) {
                printk(KERN_WARNING "%s: failed to allocate CM SRQ ring (%d entries)\n",
                       priv->ca->name, ipoib_recvq_size);
                ib_destroy_srq(priv->cm.srq);
                priv->cm.srq = NULL;
                return;
        }

        memset(priv->cm.srq_ring, 0, ipoib_recvq_size * sizeof *priv->cm.srq_ring);
}

int ipoib_cm_dev_init(struct ipoib_dev_priv *priv)
{
        if_t dev = priv->dev;
        int i;
        int max_srq_sge;

        INIT_LIST_HEAD(&priv->cm.passive_ids);
        INIT_LIST_HEAD(&priv->cm.reap_list);
        INIT_LIST_HEAD(&priv->cm.start_list);
        INIT_LIST_HEAD(&priv->cm.rx_error_list);
        INIT_LIST_HEAD(&priv->cm.rx_flush_list);
        INIT_LIST_HEAD(&priv->cm.rx_drain_list);
        INIT_LIST_HEAD(&priv->cm.rx_reap_list);
        INIT_WORK(&priv->cm.start_task, ipoib_cm_tx_start);
        INIT_WORK(&priv->cm.reap_task, ipoib_cm_tx_reap);
        INIT_WORK(&priv->cm.mb_task, ipoib_cm_mb_reap);
        INIT_WORK(&priv->cm.rx_reap_task, ipoib_cm_rx_reap);
        INIT_DELAYED_WORK(&priv->cm.stale_task, ipoib_cm_stale_task);

        bzero(&priv->cm.mb_queue, sizeof(priv->cm.mb_queue));
        mtx_init(&priv->cm.mb_queue.ifq_mtx,
            if_name(dev), "if send queue", MTX_DEF);

        max_srq_sge = priv->ca->attrs.max_srq_sge;

        ipoib_dbg(priv, "max_srq_sge=%d\n", max_srq_sge);

        max_srq_sge = min_t(int, IPOIB_CM_RX_SG, max_srq_sge);
        ipoib_cm_create_srq(priv, max_srq_sge);
        if (ipoib_cm_has_srq(priv)) {
                priv->cm.max_cm_mtu = max_srq_sge * MJUMPAGESIZE;
                priv->cm.num_frags  = max_srq_sge;
                ipoib_dbg(priv, "max_cm_mtu = 0x%x, num_frags=%d\n",
                          priv->cm.max_cm_mtu, priv->cm.num_frags);
        } else {
                priv->cm.max_cm_mtu = IPOIB_CM_MAX_MTU;
                priv->cm.num_frags  = IPOIB_CM_RX_SG;
        }

        ipoib_cm_init_rx_wr(priv, &priv->cm.rx_wr, priv->cm.rx_sge);

        if (ipoib_cm_has_srq(priv)) {
                for (i = 0; i < ipoib_recvq_size; ++i) {
                        if (!ipoib_cm_alloc_rx_mb(priv, &priv->cm.srq_ring[i])) {
                                ipoib_warn(priv, "failed to allocate "
                                           "receive buffer %d\n", i);
                                ipoib_cm_dev_cleanup(priv);
                                return -ENOMEM;
                        }

                        if (ipoib_cm_post_receive_srq(priv, i)) {
                                ipoib_warn(priv, "ipoib_cm_post_receive_srq "
                                           "failed for buf %d\n", i);
                                ipoib_cm_dev_cleanup(priv);
                                return -EIO;
                        }
                }
        }

        if_getlladdr(priv->dev)[0] = IPOIB_FLAGS_RC;
        return 0;
}

void ipoib_cm_dev_cleanup(struct ipoib_dev_priv *priv)
{
        int ret;

        if (!priv->cm.srq)
                return;

        ipoib_dbg(priv, "Cleanup ipoib connected mode.\n");

        ret = ib_destroy_srq(priv->cm.srq);
        if (ret)
                ipoib_warn(priv, "ib_destroy_srq failed: %d\n", ret);

        priv->cm.srq = NULL;
        if (!priv->cm.srq_ring)
                return;

        ipoib_cm_free_rx_ring(priv, priv->cm.srq_ring);
        priv->cm.srq_ring = NULL;

        mtx_destroy(&priv->cm.mb_queue.ifq_mtx);
}

#endif /* CONFIG_INFINIBAND_IPOIB_CM */