qib_qp.c

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/*
 * Copyright (c) 2012 Intel Corporation.  All rights reserved.
 * Copyright (c) 2006 - 2012 QLogic Corporation.  * All rights reserved.
 * Copyright (c) 2005, 2006 PathScale, 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/err.h>
#include <linux/vmalloc.h>
#include <linux/jhash.h>

#include "qib.h"

#define BITS_PER_PAGE           (PAGE_SIZE*BITS_PER_BYTE)
#define BITS_PER_PAGE_MASK      (BITS_PER_PAGE-1)

static inline unsigned mk_qpn(struct qib_qpn_table *qpt,
                  struct qpn_map *map, unsigned off)
{
    return (map - qpt->map) * BITS_PER_PAGE + off;
}

static inline unsigned find_next_offset(struct qib_qpn_table *qpt,
                    struct qpn_map *map, unsigned off,
                    unsigned n)
{
    if (qpt->mask) {
        off++;
        if (((off & qpt->mask) >> 1) >= n)
            off = (off | qpt->mask) + 2;
    } else
        off = find_next_zero_bit(map->page, BITS_PER_PAGE, off);
    return off;
}

/*
 * Convert the AETH credit code into the number of credits.
 */
static u32 credit_table[31] = {
    0,                      /* 0 */
    1,                      /* 1 */
    2,                      /* 2 */
    3,                      /* 3 */
    4,                      /* 4 */
    6,                      /* 5 */
    8,                      /* 6 */
    12,                     /* 7 */
    16,                     /* 8 */
    24,                     /* 9 */
    32,                     /* A */
    48,                     /* B */
    64,                     /* C */
    96,                     /* D */
    128,                    /* E */
    192,                    /* F */
    256,                    /* 10 */
    384,                    /* 11 */
    512,                    /* 12 */
    768,                    /* 13 */
    1024,                   /* 14 */
    1536,                   /* 15 */
    2048,                   /* 16 */
    3072,                   /* 17 */
    4096,                   /* 18 */
    6144,                   /* 19 */
    8192,                   /* 1A */
    12288,                  /* 1B */
    16384,                  /* 1C */
    24576,                  /* 1D */
    32768                   /* 1E */
};

static void get_map_page(struct qib_qpn_table *qpt, struct qpn_map *map)
{
    unsigned long page = get_zeroed_page(GFP_KERNEL);

    /*
     * Free the page if someone raced with us installing it.
     */

    spin_lock(&qpt->lock);
    if (map->page)
        free_page(page);
    else
        map->page = (void *)page;
    spin_unlock(&qpt->lock);
}

/*
 * Allocate the next available QPN or
 * zero/one for QP type IB_QPT_SMI/IB_QPT_GSI.
 */
static int alloc_qpn(struct qib_devdata *dd, struct qib_qpn_table *qpt,
             enum ib_qp_type type, u8 port)
{
    u32 i, offset, max_scan, qpn;
    struct qpn_map *map;
    u32 ret;

    if (type == IB_QPT_SMI || type == IB_QPT_GSI) {
        unsigned n;

        ret = type == IB_QPT_GSI;
        n = 1 << (ret + 2 * (port - 1));
        spin_lock(&qpt->lock);
        if (qpt->flags & n)
            ret = -EINVAL;
        else
            qpt->flags |= n;
        spin_unlock(&qpt->lock);
        goto bail;
    }

    qpn = qpt->last + 2;
    if (qpn >= QPN_MAX)
        qpn = 2;
    if (qpt->mask && ((qpn & qpt->mask) >> 1) >= dd->n_krcv_queues)
        qpn = (qpn | qpt->mask) + 2;
    offset = qpn & BITS_PER_PAGE_MASK;
    map = &qpt->map[qpn / BITS_PER_PAGE];
    max_scan = qpt->nmaps - !offset;
    for (i = 0;;) {
        if (unlikely(!map->page)) {
            get_map_page(qpt, map);
            if (unlikely(!map->page))
                break;
        }
        do {
            if (!test_and_set_bit(offset, map->page)) {
                qpt->last = qpn;
                ret = qpn;
                goto bail;
            }
            offset = find_next_offset(qpt, map, offset,
                dd->n_krcv_queues);
            qpn = mk_qpn(qpt, map, offset);
            /*
             * This test differs from alloc_pidmap().
             * If find_next_offset() does find a zero
             * bit, we don't need to check for QPN
             * wrapping around past our starting QPN.
             * We just need to be sure we don't loop
             * forever.
             */
        } while (offset < BITS_PER_PAGE && qpn < QPN_MAX);
        /*
         * In order to keep the number of pages allocated to a
         * minimum, we scan the all existing pages before increasing
         * the size of the bitmap table.
         */
        if (++i > max_scan) {
            if (qpt->nmaps == QPNMAP_ENTRIES)
                break;
            map = &qpt->map[qpt->nmaps++];
            offset = 0;
        } else if (map < &qpt->map[qpt->nmaps]) {
            ++map;
            offset = 0;
        } else {
            map = &qpt->map[0];
            offset = 2;
        }
        qpn = mk_qpn(qpt, map, offset);
    }

    ret = -ENOMEM;

bail:
    return ret;
}

static void free_qpn(struct qib_qpn_table *qpt, u32 qpn)
{
    struct qpn_map *map;

    map = qpt->map + qpn / BITS_PER_PAGE;
    if (map->page)
        clear_bit(qpn & BITS_PER_PAGE_MASK, map->page);
}

static inline unsigned qpn_hash(struct qib_ibdev *dev, u32 qpn)
{
    return jhash_1word(qpn, dev->qp_rnd) &
        (dev->qp_table_size - 1);
}


/*
 * Put the QP into the hash table.
 * The hash table holds a reference to the QP.
 */
static void insert_qp(struct qib_ibdev *dev, struct qib_qp *qp)
{
    struct qib_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
    unsigned long flags;
    unsigned n = qpn_hash(dev, qp->ibqp.qp_num);

    spin_lock_irqsave(&dev->qpt_lock, flags);
    atomic_inc(&qp->refcount);

    if (qp->ibqp.qp_num == 0)
        rcu_assign_pointer(ibp->qp0, qp);
    else if (qp->ibqp.qp_num == 1)
        rcu_assign_pointer(ibp->qp1, qp);
    else {
        qp->next = dev->qp_table[n];
        rcu_assign_pointer(dev->qp_table[n], qp);
    }

    spin_unlock_irqrestore(&dev->qpt_lock, flags);
    synchronize_rcu();
}

/*
 * Remove the QP from the table so it can't be found asynchronously by
 * the receive interrupt routine.
 */
static void remove_qp(struct qib_ibdev *dev, struct qib_qp *qp)
{
    struct qib_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
    unsigned n = qpn_hash(dev, qp->ibqp.qp_num);
    unsigned long flags;

    spin_lock_irqsave(&dev->qpt_lock, flags);

    if (rcu_dereference_protected(ibp->qp0,
            lockdep_is_held(&dev->qpt_lock)) == qp) {
        atomic_dec(&qp->refcount);
        rcu_assign_pointer(ibp->qp0, NULL);
    } else if (rcu_dereference_protected(ibp->qp1,
            lockdep_is_held(&dev->qpt_lock)) == qp) {
        atomic_dec(&qp->refcount);
        rcu_assign_pointer(ibp->qp1, NULL);
    } else {
        struct qib_qp *q;
        struct qib_qp __rcu **qpp;

        qpp = &dev->qp_table[n];
        q = rcu_dereference_protected(*qpp,
            lockdep_is_held(&dev->qpt_lock));
        for (; q; qpp = &q->next) {
            if (q == qp) {
                atomic_dec(&qp->refcount);
                *qpp = qp->next;
                rcu_assign_pointer(qp->next, NULL);
                q = rcu_dereference_protected(*qpp,
                    lockdep_is_held(&dev->qpt_lock));
                break;
            }
            q = rcu_dereference_protected(*qpp,
                lockdep_is_held(&dev->qpt_lock));
        }
    }

    spin_unlock_irqrestore(&dev->qpt_lock, flags);
    synchronize_rcu();
}

unsigned qib_free_all_qps(struct qib_devdata *dd)
{
    struct qib_ibdev *dev = &dd->verbs_dev;
    unsigned long flags;
    struct qib_qp *qp;
    unsigned n, qp_inuse = 0;

    for (n = 0; n < dd->num_pports; n++) {
        struct qib_ibport *ibp = &dd->pport[n].ibport_data;

        if (!qib_mcast_tree_empty(ibp))
            qp_inuse++;
        rcu_read_lock();
        if (rcu_dereference(ibp->qp0))
            qp_inuse++;
        if (rcu_dereference(ibp->qp1))
            qp_inuse++;
        rcu_read_unlock();
    }

    spin_lock_irqsave(&dev->qpt_lock, flags);
    for (n = 0; n < dev->qp_table_size; n++) {
        qp = rcu_dereference_protected(dev->qp_table[n],
            lockdep_is_held(&dev->qpt_lock));
        rcu_assign_pointer(dev->qp_table[n], NULL);

        for (; qp; qp = rcu_dereference_protected(qp->next,
                    lockdep_is_held(&dev->qpt_lock)))
            qp_inuse++;
    }
    spin_unlock_irqrestore(&dev->qpt_lock, flags);
    synchronize_rcu();

    return qp_inuse;
}

struct qib_qp *qib_lookup_qpn(struct qib_ibport *ibp, u32 qpn)
{
    struct qib_qp *qp = NULL;

    if (unlikely(qpn <= 1)) {
        rcu_read_lock();
        if (qpn == 0)
            qp = rcu_dereference(ibp->qp0);
        else
            qp = rcu_dereference(ibp->qp1);
    } else {
        struct qib_ibdev *dev = &ppd_from_ibp(ibp)->dd->verbs_dev;
        unsigned n = qpn_hash(dev, qpn);

        rcu_read_lock();
        for (qp = rcu_dereference(dev->qp_table[n]); qp;
            qp = rcu_dereference(qp->next))
            if (qp->ibqp.qp_num == qpn)
                break;
    }
    if (qp)
        if (unlikely(!atomic_inc_not_zero(&qp->refcount)))
            qp = NULL;

    rcu_read_unlock();
    return qp;
}

static void qib_reset_qp(struct qib_qp *qp, enum ib_qp_type type)
{
    qp->remote_qpn = 0;
    qp->qkey = 0;
    qp->qp_access_flags = 0;
    atomic_set(&qp->s_dma_busy, 0);
    qp->s_flags &= QIB_S_SIGNAL_REQ_WR;
    qp->s_hdrwords = 0;
    qp->s_wqe = NULL;
    qp->s_draining = 0;
    qp->s_next_psn = 0;
    qp->s_last_psn = 0;
    qp->s_sending_psn = 0;
    qp->s_sending_hpsn = 0;
    qp->s_psn = 0;
    qp->r_psn = 0;
    qp->r_msn = 0;
    if (type == IB_QPT_RC) {
        qp->s_state = IB_OPCODE_RC_SEND_LAST;
        qp->r_state = IB_OPCODE_RC_SEND_LAST;
    } else {
        qp->s_state = IB_OPCODE_UC_SEND_LAST;
        qp->r_state = IB_OPCODE_UC_SEND_LAST;
    }
    qp->s_ack_state = IB_OPCODE_RC_ACKNOWLEDGE;
    qp->r_nak_state = 0;
    qp->r_aflags = 0;
    qp->r_flags = 0;
    qp->s_head = 0;
    qp->s_tail = 0;
    qp->s_cur = 0;
    qp->s_acked = 0;
    qp->s_last = 0;
    qp->s_ssn = 1;
    qp->s_lsn = 0;
    qp->s_mig_state = IB_MIG_MIGRATED;
    memset(qp->s_ack_queue, 0, sizeof(qp->s_ack_queue));
    qp->r_head_ack_queue = 0;
    qp->s_tail_ack_queue = 0;
    qp->s_num_rd_atomic = 0;
    if (qp->r_rq.wq) {
        qp->r_rq.wq->head = 0;
        qp->r_rq.wq->tail = 0;
    }
    qp->r_sge.num_sge = 0;
}

static void clear_mr_refs(struct qib_qp *qp, int clr_sends)
{
    unsigned n;

    if (test_and_clear_bit(QIB_R_REWIND_SGE, &qp->r_aflags))
        qib_put_ss(&qp->s_rdma_read_sge);

    qib_put_ss(&qp->r_sge);

    if (clr_sends) {
        while (qp->s_last != qp->s_head) {
            struct qib_swqe *wqe = get_swqe_ptr(qp, qp->s_last);
            unsigned i;

            for (i = 0; i < wqe->wr.num_sge; i++) {
                struct qib_sge *sge = &wqe->sg_list[i];

                qib_put_mr(sge->mr);
            }
            if (qp->ibqp.qp_type == IB_QPT_UD ||
                qp->ibqp.qp_type == IB_QPT_SMI ||
                qp->ibqp.qp_type == IB_QPT_GSI)
                atomic_dec(&to_iah(wqe->wr.wr.ud.ah)->refcount);
            if (++qp->s_last >= qp->s_size)
                qp->s_last = 0;
        }
        if (qp->s_rdma_mr) {
            qib_put_mr(qp->s_rdma_mr);
            qp->s_rdma_mr = NULL;
        }
    }

    if (qp->ibqp.qp_type != IB_QPT_RC)
        return;

    for (n = 0; n < ARRAY_SIZE(qp->s_ack_queue); n++) {
        struct qib_ack_entry *e = &qp->s_ack_queue[n];

        if (e->opcode == IB_OPCODE_RC_RDMA_READ_REQUEST &&
            e->rdma_sge.mr) {
            qib_put_mr(e->rdma_sge.mr);
            e->rdma_sge.mr = NULL;
        }
    }
}

int qib_error_qp(struct qib_qp *qp, enum ib_wc_status err)
{
    struct qib_ibdev *dev = to_idev(qp->ibqp.device);
    struct ib_wc wc;
    int ret = 0;

    if (qp->state == IB_QPS_ERR || qp->state == IB_QPS_RESET)
        goto bail;

    qp->state = IB_QPS_ERR;

    if (qp->s_flags & (QIB_S_TIMER | QIB_S_WAIT_RNR)) {
        qp->s_flags &= ~(QIB_S_TIMER | QIB_S_WAIT_RNR);
        del_timer(&qp->s_timer);
    }

    if (qp->s_flags & QIB_S_ANY_WAIT_SEND)
        qp->s_flags &= ~QIB_S_ANY_WAIT_SEND;

    spin_lock(&dev->pending_lock);
    if (!list_empty(&qp->iowait) && !(qp->s_flags & QIB_S_BUSY)) {
        qp->s_flags &= ~QIB_S_ANY_WAIT_IO;
        list_del_init(&qp->iowait);
    }
    spin_unlock(&dev->pending_lock);

    if (!(qp->s_flags & QIB_S_BUSY)) {
        qp->s_hdrwords = 0;
        if (qp->s_rdma_mr) {
            qib_put_mr(qp->s_rdma_mr);
            qp->s_rdma_mr = NULL;
        }
        if (qp->s_tx) {
            qib_put_txreq(qp->s_tx);
            qp->s_tx = NULL;
        }
    }

    /* Schedule the sending tasklet to drain the send work queue. */
    if (qp->s_last != qp->s_head)
        qib_schedule_send(qp);

    clear_mr_refs(qp, 0);

    memset(&wc, 0, sizeof(wc));
    wc.qp = &qp->ibqp;
    wc.opcode = IB_WC_RECV;

    if (test_and_clear_bit(QIB_R_WRID_VALID, &qp->r_aflags)) {
        wc.wr_id = qp->r_wr_id;
        wc.status = err;
        qib_cq_enter(to_icq(qp->ibqp.recv_cq), &wc, 1);
    }
    wc.status = IB_WC_WR_FLUSH_ERR;

    if (qp->r_rq.wq) {
        struct qib_rwq *wq;
        u32 head;
        u32 tail;

        spin_lock(&qp->r_rq.lock);

        /* sanity check pointers before trusting them */
        wq = qp->r_rq.wq;
        head = wq->head;
        if (head >= qp->r_rq.size)
            head = 0;
        tail = wq->tail;
        if (tail >= qp->r_rq.size)
            tail = 0;
        while (tail != head) {
            wc.wr_id = get_rwqe_ptr(&qp->r_rq, tail)->wr_id;
            if (++tail >= qp->r_rq.size)
                tail = 0;
            qib_cq_enter(to_icq(qp->ibqp.recv_cq), &wc, 1);
        }
        wq->tail = tail;

        spin_unlock(&qp->r_rq.lock);
    } else if (qp->ibqp.event_handler)
        ret = 1;

bail:
    return ret;
}

int qib_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
          int attr_mask, struct ib_udata *udata)
{
    struct qib_ibdev *dev = to_idev(ibqp->device);
    struct qib_qp *qp = to_iqp(ibqp);
    enum ib_qp_state cur_state, new_state;
    struct ib_event ev;
    int lastwqe = 0;
    int mig = 0;
    int ret;
    u32 pmtu = 0; /* for gcc warning only */

    spin_lock_irq(&qp->r_lock);
    spin_lock(&qp->s_lock);

    cur_state = attr_mask & IB_QP_CUR_STATE ?
        attr->cur_qp_state : qp->state;
    new_state = attr_mask & IB_QP_STATE ? attr->qp_state : cur_state;

    if (!ib_modify_qp_is_ok(cur_state, new_state, ibqp->qp_type,
                attr_mask))
        goto inval;

    if (attr_mask & IB_QP_AV) {
        if (attr->ah_attr.dlid >= QIB_MULTICAST_LID_BASE)
            goto inval;
        if (qib_check_ah(qp->ibqp.device, &attr->ah_attr))
            goto inval;
    }

    if (attr_mask & IB_QP_ALT_PATH) {
        if (attr->alt_ah_attr.dlid >= QIB_MULTICAST_LID_BASE)
            goto inval;
        if (qib_check_ah(qp->ibqp.device, &attr->alt_ah_attr))
            goto inval;
        if (attr->alt_pkey_index >= qib_get_npkeys(dd_from_dev(dev)))
            goto inval;
    }

    if (attr_mask & IB_QP_PKEY_INDEX)
        if (attr->pkey_index >= qib_get_npkeys(dd_from_dev(dev)))
            goto inval;

    if (attr_mask & IB_QP_MIN_RNR_TIMER)
        if (attr->min_rnr_timer > 31)
            goto inval;

    if (attr_mask & IB_QP_PORT)
        if (qp->ibqp.qp_type == IB_QPT_SMI ||
            qp->ibqp.qp_type == IB_QPT_GSI ||
            attr->port_num == 0 ||
            attr->port_num > ibqp->device->phys_port_cnt)
            goto inval;

    if (attr_mask & IB_QP_DEST_QPN)
        if (attr->dest_qp_num > QIB_QPN_MASK)
            goto inval;

    if (attr_mask & IB_QP_RETRY_CNT)
        if (attr->retry_cnt > 7)
            goto inval;

    if (attr_mask & IB_QP_RNR_RETRY)
        if (attr->rnr_retry > 7)
            goto inval;

    /*
     * Don't allow invalid path_mtu values.  OK to set greater
     * than the active mtu (or even the max_cap, if we have tuned
     * that to a small mtu.  We'll set qp->path_mtu
     * to the lesser of requested attribute mtu and active,
     * for packetizing messages.
     * Note that the QP port has to be set in INIT and MTU in RTR.
     */
    if (attr_mask & IB_QP_PATH_MTU) {
        struct qib_devdata *dd = dd_from_dev(dev);
        int mtu, pidx = qp->port_num - 1;

        mtu = ib_mtu_enum_to_int(attr->path_mtu);
        if (mtu == -1)
            goto inval;
        if (mtu > dd->pport[pidx].ibmtu) {
            switch (dd->pport[pidx].ibmtu) {
            case 4096:
                pmtu = IB_MTU_4096;
                break;
            case 2048:
                pmtu = IB_MTU_2048;
                break;
            case 1024:
                pmtu = IB_MTU_1024;
                break;
            case 512:
                pmtu = IB_MTU_512;
                break;
            case 256:
                pmtu = IB_MTU_256;
                break;
            default:
                pmtu = IB_MTU_2048;
            }
        } else
            pmtu = attr->path_mtu;
    }

    if (attr_mask & IB_QP_PATH_MIG_STATE) {
        if (attr->path_mig_state == IB_MIG_REARM) {
            if (qp->s_mig_state == IB_MIG_ARMED)
                goto inval;
            if (new_state != IB_QPS_RTS)
                goto inval;
        } else if (attr->path_mig_state == IB_MIG_MIGRATED) {
            if (qp->s_mig_state == IB_MIG_REARM)
                goto inval;
            if (new_state != IB_QPS_RTS && new_state != IB_QPS_SQD)
                goto inval;
            if (qp->s_mig_state == IB_MIG_ARMED)
                mig = 1;
        } else
            goto inval;
    }

    if (attr_mask & IB_QP_MAX_DEST_RD_ATOMIC)
        if (attr->max_dest_rd_atomic > QIB_MAX_RDMA_ATOMIC)
            goto inval;

    switch (new_state) {
    case IB_QPS_RESET:
        if (qp->state != IB_QPS_RESET) {
            qp->state = IB_QPS_RESET;
            spin_lock(&dev->pending_lock);
            if (!list_empty(&qp->iowait))
                list_del_init(&qp->iowait);
            spin_unlock(&dev->pending_lock);
            qp->s_flags &= ~(QIB_S_TIMER | QIB_S_ANY_WAIT);
            spin_unlock(&qp->s_lock);
            spin_unlock_irq(&qp->r_lock);
            /* Stop the sending work queue and retry timer */
            cancel_work_sync(&qp->s_work);
            del_timer_sync(&qp->s_timer);
            wait_event(qp->wait_dma, !atomic_read(&qp->s_dma_busy));
            if (qp->s_tx) {
                qib_put_txreq(qp->s_tx);
                qp->s_tx = NULL;
            }
            remove_qp(dev, qp);
            wait_event(qp->wait, !atomic_read(&qp->refcount));
            spin_lock_irq(&qp->r_lock);
            spin_lock(&qp->s_lock);
            clear_mr_refs(qp, 1);
            qib_reset_qp(qp, ibqp->qp_type);
        }
        break;

    case IB_QPS_RTR:
        /* Allow event to retrigger if QP set to RTR more than once */
        qp->r_flags &= ~QIB_R_COMM_EST;
        qp->state = new_state;
        break;

    case IB_QPS_SQD:
        qp->s_draining = qp->s_last != qp->s_cur;
        qp->state = new_state;
        break;

    case IB_QPS_SQE:
        if (qp->ibqp.qp_type == IB_QPT_RC)
            goto inval;
        qp->state = new_state;
        break;

    case IB_QPS_ERR:
        lastwqe = qib_error_qp(qp, IB_WC_WR_FLUSH_ERR);
        break;

    default:
        qp->state = new_state;
        break;
    }

    if (attr_mask & IB_QP_PKEY_INDEX)
        qp->s_pkey_index = attr->pkey_index;

    if (attr_mask & IB_QP_PORT)
        qp->port_num = attr->port_num;

    if (attr_mask & IB_QP_DEST_QPN)
        qp->remote_qpn = attr->dest_qp_num;

    if (attr_mask & IB_QP_SQ_PSN) {
        qp->s_next_psn = attr->sq_psn & QIB_PSN_MASK;
        qp->s_psn = qp->s_next_psn;
        qp->s_sending_psn = qp->s_next_psn;
        qp->s_last_psn = qp->s_next_psn - 1;
        qp->s_sending_hpsn = qp->s_last_psn;
    }

    if (attr_mask & IB_QP_RQ_PSN)
        qp->r_psn = attr->rq_psn & QIB_PSN_MASK;

    if (attr_mask & IB_QP_ACCESS_FLAGS)
        qp->qp_access_flags = attr->qp_access_flags;

    if (attr_mask & IB_QP_AV) {
        qp->remote_ah_attr = attr->ah_attr;
        qp->s_srate = attr->ah_attr.static_rate;
    }

    if (attr_mask & IB_QP_ALT_PATH) {
        qp->alt_ah_attr = attr->alt_ah_attr;
        qp->s_alt_pkey_index = attr->alt_pkey_index;
    }

    if (attr_mask & IB_QP_PATH_MIG_STATE) {
        qp->s_mig_state = attr->path_mig_state;
        if (mig) {
            qp->remote_ah_attr = qp->alt_ah_attr;
            qp->port_num = qp->alt_ah_attr.port_num;
            qp->s_pkey_index = qp->s_alt_pkey_index;
        }
    }

    if (attr_mask & IB_QP_PATH_MTU) {
        qp->path_mtu = pmtu;
        qp->pmtu = ib_mtu_enum_to_int(pmtu);
    }

    if (attr_mask & IB_QP_RETRY_CNT) {
        qp->s_retry_cnt = attr->retry_cnt;
        qp->s_retry = attr->retry_cnt;
    }

    if (attr_mask & IB_QP_RNR_RETRY) {
        qp->s_rnr_retry_cnt = attr->rnr_retry;
        qp->s_rnr_retry = attr->rnr_retry;
    }

    if (attr_mask & IB_QP_MIN_RNR_TIMER)
        qp->r_min_rnr_timer = attr->min_rnr_timer;

    if (attr_mask & IB_QP_TIMEOUT) {
        qp->timeout = attr->timeout;
        qp->timeout_jiffies =
            usecs_to_jiffies((4096UL * (1UL << qp->timeout)) /
                1000UL);
    }

    if (attr_mask & IB_QP_QKEY)
        qp->qkey = attr->qkey;

    if (attr_mask & IB_QP_MAX_DEST_RD_ATOMIC)
        qp->r_max_rd_atomic = attr->max_dest_rd_atomic;

    if (attr_mask & IB_QP_MAX_QP_RD_ATOMIC)
        qp->s_max_rd_atomic = attr->max_rd_atomic;

    spin_unlock(&qp->s_lock);
    spin_unlock_irq(&qp->r_lock);

    if (cur_state == IB_QPS_RESET && new_state == IB_QPS_INIT)
        insert_qp(dev, qp);

    if (lastwqe) {
        ev.device = qp->ibqp.device;
        ev.element.qp = &qp->ibqp;
        ev.event = IB_EVENT_QP_LAST_WQE_REACHED;
        qp->ibqp.event_handler(&ev, qp->ibqp.qp_context);
    }
    if (mig) {
        ev.device = qp->ibqp.device;
        ev.element.qp = &qp->ibqp;
        ev.event = IB_EVENT_PATH_MIG;
        qp->ibqp.event_handler(&ev, qp->ibqp.qp_context);
    }
    ret = 0;
    goto bail;

inval:
    spin_unlock(&qp->s_lock);
    spin_unlock_irq(&qp->r_lock);
    ret = -EINVAL;

bail:
    return ret;
}

int qib_query_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
         int attr_mask, struct ib_qp_init_attr *init_attr)
{
    struct qib_qp *qp = to_iqp(ibqp);

    attr->qp_state = qp->state;
    attr->cur_qp_state = attr->qp_state;
    attr->path_mtu = qp->path_mtu;
    attr->path_mig_state = qp->s_mig_state;
    attr->qkey = qp->qkey;
    attr->rq_psn = qp->r_psn & QIB_PSN_MASK;
    attr->sq_psn = qp->s_next_psn & QIB_PSN_MASK;
    attr->dest_qp_num = qp->remote_qpn;
    attr->qp_access_flags = qp->qp_access_flags;
    attr->cap.max_send_wr = qp->s_size - 1;
    attr->cap.max_recv_wr = qp->ibqp.srq ? 0 : qp->r_rq.size - 1;
    attr->cap.max_send_sge = qp->s_max_sge;
    attr->cap.max_recv_sge = qp->r_rq.max_sge;
    attr->cap.max_inline_data = 0;
    attr->ah_attr = qp->remote_ah_attr;
    attr->alt_ah_attr = qp->alt_ah_attr;
    attr->pkey_index = qp->s_pkey_index;
    attr->alt_pkey_index = qp->s_alt_pkey_index;
    attr->en_sqd_async_notify = 0;
    attr->sq_draining = qp->s_draining;
    attr->max_rd_atomic = qp->s_max_rd_atomic;
    attr->max_dest_rd_atomic = qp->r_max_rd_atomic;
    attr->min_rnr_timer = qp->r_min_rnr_timer;
    attr->port_num = qp->port_num;
    attr->timeout = qp->timeout;
    attr->retry_cnt = qp->s_retry_cnt;
    attr->rnr_retry = qp->s_rnr_retry_cnt;
    attr->alt_port_num = qp->alt_ah_attr.port_num;
    attr->alt_timeout = qp->alt_timeout;

    init_attr->event_handler = qp->ibqp.event_handler;
    init_attr->qp_context = qp->ibqp.qp_context;
    init_attr->send_cq = qp->ibqp.send_cq;
    init_attr->recv_cq = qp->ibqp.recv_cq;
    init_attr->srq = qp->ibqp.srq;
    init_attr->cap = attr->cap;
    if (qp->s_flags & QIB_S_SIGNAL_REQ_WR)
        init_attr->sq_sig_type = IB_SIGNAL_REQ_WR;
    else
        init_attr->sq_sig_type = IB_SIGNAL_ALL_WR;
    init_attr->qp_type = qp->ibqp.qp_type;
    init_attr->port_num = qp->port_num;
    return 0;
}

__be32 qib_compute_aeth(struct qib_qp *qp)
{
    u32 aeth = qp->r_msn & QIB_MSN_MASK;

    if (qp->ibqp.srq) {
        /*
         * Shared receive queues don't generate credits.
         * Set the credit field to the invalid value.
         */
        aeth |= QIB_AETH_CREDIT_INVAL << QIB_AETH_CREDIT_SHIFT;
    } else {
        u32 min, max, x;
        u32 credits;
        struct qib_rwq *wq = qp->r_rq.wq;
        u32 head;
        u32 tail;

        /* sanity check pointers before trusting them */
        head = wq->head;
        if (head >= qp->r_rq.size)
            head = 0;
        tail = wq->tail;
        if (tail >= qp->r_rq.size)
            tail = 0;
        /*
         * Compute the number of credits available (RWQEs).
         * XXX Not holding the r_rq.lock here so there is a small
         * chance that the pair of reads are not atomic.
         */
        credits = head - tail;
        if ((int)credits < 0)
            credits += qp->r_rq.size;
        /*
         * Binary search the credit table to find the code to
         * use.
         */
        min = 0;
        max = 31;
        for (;;) {
            x = (min + max) / 2;
            if (credit_table[x] == credits)
                break;
            if (credit_table[x] > credits)
                max = x;
            else if (min == x)
                break;
            else
                min = x;
        }
        aeth |= x << QIB_AETH_CREDIT_SHIFT;
    }
    return cpu_to_be32(aeth);
}

struct ib_qp *qib_create_qp(struct ib_pd *ibpd,
                struct ib_qp_init_attr *init_attr,
                struct ib_udata *udata)
{
    struct qib_qp *qp;
    int err;
    struct qib_swqe *swq = NULL;
    struct qib_ibdev *dev;
    struct qib_devdata *dd;
    size_t sz;
    size_t sg_list_sz;
    struct ib_qp *ret;

    if (init_attr->cap.max_send_sge > ib_qib_max_sges ||
        init_attr->cap.max_send_wr > ib_qib_max_qp_wrs) {
        ret = ERR_PTR(-EINVAL);
        goto bail;
    }

    /* Check receive queue parameters if no SRQ is specified. */
    if (!init_attr->srq) {
        if (init_attr->cap.max_recv_sge > ib_qib_max_sges ||
            init_attr->cap.max_recv_wr > ib_qib_max_qp_wrs) {
            ret = ERR_PTR(-EINVAL);
            goto bail;
        }
        if (init_attr->cap.max_send_sge +
            init_attr->cap.max_send_wr +
            init_attr->cap.max_recv_sge +
            init_attr->cap.max_recv_wr == 0) {
            ret = ERR_PTR(-EINVAL);
            goto bail;
        }
    }

    switch (init_attr->qp_type) {
    case IB_QPT_SMI:
    case IB_QPT_GSI:
        if (init_attr->port_num == 0 ||
            init_attr->port_num > ibpd->device->phys_port_cnt) {
            ret = ERR_PTR(-EINVAL);
            goto bail;
        }
    case IB_QPT_UC:
    case IB_QPT_RC:
    case IB_QPT_UD:
        sz = sizeof(struct qib_sge) *
            init_attr->cap.max_send_sge +
            sizeof(struct qib_swqe);
        swq = vmalloc((init_attr->cap.max_send_wr + 1) * sz);
        if (swq == NULL) {
            ret = ERR_PTR(-ENOMEM);
            goto bail;
        }
        sz = sizeof(*qp);
        sg_list_sz = 0;
        if (init_attr->srq) {
            struct qib_srq *srq = to_isrq(init_attr->srq);

            if (srq->rq.max_sge > 1)
                sg_list_sz = sizeof(*qp->r_sg_list) *
                    (srq->rq.max_sge - 1);
        } else if (init_attr->cap.max_recv_sge > 1)
            sg_list_sz = sizeof(*qp->r_sg_list) *
                (init_attr->cap.max_recv_sge - 1);
        qp = kzalloc(sz + sg_list_sz, GFP_KERNEL);
        if (!qp) {
            ret = ERR_PTR(-ENOMEM);
            goto bail_swq;
        }
        RCU_INIT_POINTER(qp->next, NULL);
        qp->s_hdr = kzalloc(sizeof(*qp->s_hdr), GFP_KERNEL);
        if (!qp->s_hdr) {
            ret = ERR_PTR(-ENOMEM);
            goto bail_qp;
        }
        qp->timeout_jiffies =
            usecs_to_jiffies((4096UL * (1UL << qp->timeout)) /
                1000UL);
        if (init_attr->srq)
            sz = 0;
        else {
            qp->r_rq.size = init_attr->cap.max_recv_wr + 1;
            qp->r_rq.max_sge = init_attr->cap.max_recv_sge;
            sz = (sizeof(struct ib_sge) * qp->r_rq.max_sge) +
                sizeof(struct qib_rwqe);
            qp->r_rq.wq = vmalloc_user(sizeof(struct qib_rwq) +
                           qp->r_rq.size * sz);
            if (!qp->r_rq.wq) {
                ret = ERR_PTR(-ENOMEM);
                goto bail_qp;
            }
        }

        /*
         * ib_create_qp() will initialize qp->ibqp
         * except for qp->ibqp.qp_num.
         */
        spin_lock_init(&qp->r_lock);
        spin_lock_init(&qp->s_lock);
        spin_lock_init(&qp->r_rq.lock);
        atomic_set(&qp->refcount, 0);
        init_waitqueue_head(&qp->wait);
        init_waitqueue_head(&qp->wait_dma);
        init_timer(&qp->s_timer);
        qp->s_timer.data = (unsigned long)qp;
        INIT_WORK(&qp->s_work, qib_do_send);
        INIT_LIST_HEAD(&qp->iowait);
        INIT_LIST_HEAD(&qp->rspwait);
        qp->state = IB_QPS_RESET;
        qp->s_wq = swq;
        qp->s_size = init_attr->cap.max_send_wr + 1;
        qp->s_max_sge = init_attr->cap.max_send_sge;
        if (init_attr->sq_sig_type == IB_SIGNAL_REQ_WR)
            qp->s_flags = QIB_S_SIGNAL_REQ_WR;
        dev = to_idev(ibpd->device);
        dd = dd_from_dev(dev);
        err = alloc_qpn(dd, &dev->qpn_table, init_attr->qp_type,
                init_attr->port_num);
        if (err < 0) {
            ret = ERR_PTR(err);
            vfree(qp->r_rq.wq);
            goto bail_qp;
        }
        qp->ibqp.qp_num = err;
        qp->port_num = init_attr->port_num;
        qib_reset_qp(qp, init_attr->qp_type);
        break;

    default:
        /* Don't support raw QPs */
        ret = ERR_PTR(-ENOSYS);
        goto bail;
    }

    init_attr->cap.max_inline_data = 0;

    /*
     * Return the address of the RWQ as the offset to mmap.
     * See qib_mmap() for details.
     */
    if (udata && udata->outlen >= sizeof(__u64)) {
        if (!qp->r_rq.wq) {
            __u64 offset = 0;

            err = ib_copy_to_udata(udata, &offset,
                           sizeof(offset));
            if (err) {
                ret = ERR_PTR(err);
                goto bail_ip;
            }
        } else {
            u32 s = sizeof(struct qib_rwq) + qp->r_rq.size * sz;

            qp->ip = qib_create_mmap_info(dev, s,
                              ibpd->uobject->context,
                              qp->r_rq.wq);
            if (!qp->ip) {
                ret = ERR_PTR(-ENOMEM);
                goto bail_ip;
            }

            err = ib_copy_to_udata(udata, &(qp->ip->offset),
                           sizeof(qp->ip->offset));
            if (err) {
                ret = ERR_PTR(err);
                goto bail_ip;
            }
        }
    }

    spin_lock(&dev->n_qps_lock);
    if (dev->n_qps_allocated == ib_qib_max_qps) {
        spin_unlock(&dev->n_qps_lock);
        ret = ERR_PTR(-ENOMEM);
        goto bail_ip;
    }

    dev->n_qps_allocated++;
    spin_unlock(&dev->n_qps_lock);

    if (qp->ip) {
        spin_lock_irq(&dev->pending_lock);
        list_add(&qp->ip->pending_mmaps, &dev->pending_mmaps);
        spin_unlock_irq(&dev->pending_lock);
    }

    ret = &qp->ibqp;
    goto bail;

bail_ip:
    if (qp->ip)
        kref_put(&qp->ip->ref, qib_release_mmap_info);
    else
        vfree(qp->r_rq.wq);
    free_qpn(&dev->qpn_table, qp->ibqp.qp_num);
bail_qp:
    kfree(qp->s_hdr);
    kfree(qp);
bail_swq:
    vfree(swq);
bail:
    return ret;
}

int qib_destroy_qp(struct ib_qp *ibqp)
{
    struct qib_qp *qp = to_iqp(ibqp);
    struct qib_ibdev *dev = to_idev(ibqp->device);

    /* Make sure HW and driver activity is stopped. */
    spin_lock_irq(&qp->s_lock);
    if (qp->state != IB_QPS_RESET) {
        qp->state = IB_QPS_RESET;
        spin_lock(&dev->pending_lock);
        if (!list_empty(&qp->iowait))
            list_del_init(&qp->iowait);
        spin_unlock(&dev->pending_lock);
        qp->s_flags &= ~(QIB_S_TIMER | QIB_S_ANY_WAIT);
        spin_unlock_irq(&qp->s_lock);
        cancel_work_sync(&qp->s_work);
        del_timer_sync(&qp->s_timer);
        wait_event(qp->wait_dma, !atomic_read(&qp->s_dma_busy));
        if (qp->s_tx) {
            qib_put_txreq(qp->s_tx);
            qp->s_tx = NULL;
        }
        remove_qp(dev, qp);
        wait_event(qp->wait, !atomic_read(&qp->refcount));
        clear_mr_refs(qp, 1);
    } else
        spin_unlock_irq(&qp->s_lock);

    /* all user's cleaned up, mark it available */
    free_qpn(&dev->qpn_table, qp->ibqp.qp_num);
    spin_lock(&dev->n_qps_lock);
    dev->n_qps_allocated--;
    spin_unlock(&dev->n_qps_lock);

    if (qp->ip)
        kref_put(&qp->ip->ref, qib_release_mmap_info);
    else
        vfree(qp->r_rq.wq);
    vfree(qp->s_wq);
    kfree(qp->s_hdr);
    kfree(qp);
    return 0;
}

void qib_init_qpn_table(struct qib_devdata *dd, struct qib_qpn_table *qpt)
{
    spin_lock_init(&qpt->lock);
    qpt->last = 1;          /* start with QPN 2 */
    qpt->nmaps = 1;
    qpt->mask = dd->qpn_mask;
}

void qib_free_qpn_table(struct qib_qpn_table *qpt)
{
    int i;

    for (i = 0; i < ARRAY_SIZE(qpt->map); i++)
        if (qpt->map[i].page)
            free_page((unsigned long) qpt->map[i].page);
}

void qib_get_credit(struct qib_qp *qp, u32 aeth)
{
    u32 credit = (aeth >> QIB_AETH_CREDIT_SHIFT) & QIB_AETH_CREDIT_MASK;

    /*
     * If the credit is invalid, we can send
     * as many packets as we like.  Otherwise, we have to
     * honor the credit field.
     */
    if (credit == QIB_AETH_CREDIT_INVAL) {
        if (!(qp->s_flags & QIB_S_UNLIMITED_CREDIT)) {
            qp->s_flags |= QIB_S_UNLIMITED_CREDIT;
            if (qp->s_flags & QIB_S_WAIT_SSN_CREDIT) {
                qp->s_flags &= ~QIB_S_WAIT_SSN_CREDIT;
                qib_schedule_send(qp);
            }
        }
    } else if (!(qp->s_flags & QIB_S_UNLIMITED_CREDIT)) {
        /* Compute new LSN (i.e., MSN + credit) */
        credit = (aeth + credit_table[credit]) & QIB_MSN_MASK;
        if (qib_cmp24(credit, qp->s_lsn) > 0) {
            qp->s_lsn = credit;
            if (qp->s_flags & QIB_S_WAIT_SSN_CREDIT) {
                qp->s_flags &= ~QIB_S_WAIT_SSN_CREDIT;
                qib_schedule_send(qp);
            }
        }
    }
}