ipath_qp.c

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/*
 * Copyright (c) 2006, 2007, 2008 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/sched.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>

#include "ipath_verbs.h"
#include "ipath_kernel.h"

#define BITS_PER_PAGE       (PAGE_SIZE*BITS_PER_BYTE)
#define BITS_PER_PAGE_MASK  (BITS_PER_PAGE-1)
#define mk_qpn(qpt, map, off)   (((map) - (qpt)->map) * BITS_PER_PAGE + \
                 (off))
#define find_next_offset(map, off) find_next_zero_bit((map)->page, \
                              BITS_PER_PAGE, 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 ipath_qp_table *qpt, struct qpn_map *map)
{
    unsigned long page = get_zeroed_page(GFP_KERNEL);
    unsigned long flags;

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

    spin_lock_irqsave(&qpt->lock, flags);
    if (map->page)
        free_page(page);
    else
        map->page = (void *)page;
    spin_unlock_irqrestore(&qpt->lock, flags);
}


static int alloc_qpn(struct ipath_qp_table *qpt, enum ib_qp_type type)
{
    u32 i, offset, max_scan, qpn;
    struct qpn_map *map;
    u32 ret = -1;

    if (type == IB_QPT_SMI)
        ret = 0;
    else if (type == IB_QPT_GSI)
        ret = 1;

    if (ret != -1) {
        map = &qpt->map[0];
        if (unlikely(!map->page)) {
            get_map_page(qpt, map);
            if (unlikely(!map->page)) {
                ret = -ENOMEM;
                goto bail;
            }
        }
        if (!test_and_set_bit(ret, map->page))
            atomic_dec(&map->n_free);
        else
            ret = -EBUSY;
        goto bail;
    }

    qpn = qpt->last + 1;
    if (qpn >= QPN_MAX)
        qpn = 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;
        }
        if (likely(atomic_read(&map->n_free))) {
            do {
                if (!test_and_set_bit(offset, map->page)) {
                    atomic_dec(&map->n_free);
                    qpt->last = qpn;
                    ret = qpn;
                    goto bail;
                }
                offset = find_next_offset(map, offset);
                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 ipath_qp_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);
    atomic_inc(&map->n_free);
}

static int ipath_alloc_qpn(struct ipath_qp_table *qpt, struct ipath_qp *qp,
               enum ib_qp_type type)
{
    unsigned long flags;
    int ret;

    ret = alloc_qpn(qpt, type);
    if (ret < 0)
        goto bail;
    qp->ibqp.qp_num = ret;

    /* Add the QP to the hash table. */
    spin_lock_irqsave(&qpt->lock, flags);

    ret %= qpt->max;
    qp->next = qpt->table[ret];
    qpt->table[ret] = qp;
    atomic_inc(&qp->refcount);

    spin_unlock_irqrestore(&qpt->lock, flags);
    ret = 0;

bail:
    return ret;
}

static void ipath_free_qp(struct ipath_qp_table *qpt, struct ipath_qp *qp)
{
    struct ipath_qp *q, **qpp;
    unsigned long flags;

    spin_lock_irqsave(&qpt->lock, flags);

    /* Remove QP from the hash table. */
    qpp = &qpt->table[qp->ibqp.qp_num % qpt->max];
    for (; (q = *qpp) != NULL; qpp = &q->next) {
        if (q == qp) {
            *qpp = qp->next;
            qp->next = NULL;
            atomic_dec(&qp->refcount);
            break;
        }
    }

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

unsigned ipath_free_all_qps(struct ipath_qp_table *qpt)
{
    unsigned long flags;
    struct ipath_qp *qp;
    u32 n, qp_inuse = 0;

    spin_lock_irqsave(&qpt->lock, flags);
    for (n = 0; n < qpt->max; n++) {
        qp = qpt->table[n];
        qpt->table[n] = NULL;

        for (; qp; qp = qp->next)
            qp_inuse++;
    }
    spin_unlock_irqrestore(&qpt->lock, flags);

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

struct ipath_qp *ipath_lookup_qpn(struct ipath_qp_table *qpt, u32 qpn)
{
    unsigned long flags;
    struct ipath_qp *qp;

    spin_lock_irqsave(&qpt->lock, flags);

    for (qp = qpt->table[qpn % qpt->max]; qp; qp = qp->next) {
        if (qp->ibqp.qp_num == qpn) {
            atomic_inc(&qp->refcount);
            break;
        }
    }

    spin_unlock_irqrestore(&qpt->lock, flags);
    return qp;
}

static void ipath_reset_qp(struct ipath_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 &= IPATH_S_SIGNAL_REQ_WR;
    qp->s_hdrwords = 0;
    qp->s_wqe = NULL;
    qp->s_pkt_delay = 0;
    qp->s_draining = 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_rnr_timeout = 0;
    qp->s_head = 0;
    qp->s_tail = 0;
    qp->s_cur = 0;
    qp->s_last = 0;
    qp->s_ssn = 1;
    qp->s_lsn = 0;
    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;
    }
}

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

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

    qp->state = IB_QPS_ERR;

    spin_lock(&dev->pending_lock);
    if (!list_empty(&qp->timerwait))
        list_del_init(&qp->timerwait);
    if (!list_empty(&qp->piowait))
        list_del_init(&qp->piowait);
    spin_unlock(&dev->pending_lock);

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

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

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

    if (qp->r_rq.wq) {
        struct ipath_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;
            ipath_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 ipath_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
            int attr_mask, struct ib_udata *udata)
{
    struct ipath_ibdev *dev = to_idev(ibqp->device);
    struct ipath_qp *qp = to_iqp(ibqp);
    enum ib_qp_state cur_state, new_state;
    int lastwqe = 0;
    int ret;

    spin_lock_irq(&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 == 0 ||
            attr->ah_attr.dlid >= IPATH_MULTICAST_LID_BASE)
            goto inval;

        if ((attr->ah_attr.ah_flags & IB_AH_GRH) &&
            (attr->ah_attr.grh.sgid_index > 1))
            goto inval;
    }

    if (attr_mask & IB_QP_PKEY_INDEX)
        if (attr->pkey_index >= ipath_get_npkeys(dev->dd))
            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 (attr->port_num == 0 ||
            attr->port_num > ibqp->device->phys_port_cnt)
            goto inval;

    /*
     * don't allow invalid Path MTU values or greater than 2048
     * unless we are configured for a 4KB MTU
     */
    if ((attr_mask & IB_QP_PATH_MTU) &&
        (ib_mtu_enum_to_int(attr->path_mtu) == -1 ||
        (attr->path_mtu > IB_MTU_2048 && !ipath_mtu4096)))
        goto inval;

    if (attr_mask & IB_QP_PATH_MIG_STATE)
        if (attr->path_mig_state != IB_MIG_MIGRATED &&
            attr->path_mig_state != IB_MIG_REARM)
            goto inval;

    if (attr_mask & IB_QP_MAX_DEST_RD_ATOMIC)
        if (attr->max_dest_rd_atomic > IPATH_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->timerwait))
                list_del_init(&qp->timerwait);
            if (!list_empty(&qp->piowait))
                list_del_init(&qp->piowait);
            spin_unlock(&dev->pending_lock);
            qp->s_flags &= ~IPATH_S_ANY_WAIT;
            spin_unlock_irq(&qp->s_lock);
            /* Stop the sending tasklet */
            tasklet_kill(&qp->s_task);
            wait_event(qp->wait_dma, !atomic_read(&qp->s_dma_busy));
            spin_lock_irq(&qp->s_lock);
        }
        ipath_reset_qp(qp, ibqp->qp_type);
        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 = ipath_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_DEST_QPN)
        qp->remote_qpn = attr->dest_qp_num;

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

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

    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_dmult = ipath_ib_rate_to_mult(attr->ah_attr.static_rate);
    }

    if (attr_mask & IB_QP_PATH_MTU)
        qp->path_mtu = attr->path_mtu;

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

    if (attr_mask & IB_QP_RNR_RETRY) {
        qp->s_rnr_retry = attr->rnr_retry;
        if (qp->s_rnr_retry > 7)
            qp->s_rnr_retry = 7;
        qp->s_rnr_retry_cnt = qp->s_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;

    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_irq(&qp->s_lock);

    if (lastwqe) {
        struct ib_event ev;

        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);
    }
    ret = 0;
    goto bail;

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

bail:
    return ret;
}

int ipath_query_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
           int attr_mask, struct ib_qp_init_attr *init_attr)
{
    struct ipath_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 = 0;
    attr->qkey = qp->qkey;
    attr->rq_psn = qp->r_psn;
    attr->sq_psn = qp->s_next_psn;
    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;
    memset(&attr->alt_ah_attr, 0, sizeof(attr->alt_ah_attr));
    attr->pkey_index = qp->s_pkey_index;
    attr->alt_pkey_index = 0;
    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 = 1;
    attr->timeout = qp->timeout;
    attr->retry_cnt = qp->s_retry_cnt;
    attr->rnr_retry = qp->s_rnr_retry_cnt;
    attr->alt_port_num = 0;
    attr->alt_timeout = 0;

    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 & IPATH_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 = 1;
    return 0;
}

__be32 ipath_compute_aeth(struct ipath_qp *qp)
{
    u32 aeth = qp->r_msn & IPATH_MSN_MASK;

    if (qp->ibqp.srq) {
        /*
         * Shared receive queues don't generate credits.
         * Set the credit field to the invalid value.
         */
        aeth |= IPATH_AETH_CREDIT_INVAL << IPATH_AETH_CREDIT_SHIFT;
    } else {
        u32 min, max, x;
        u32 credits;
        struct ipath_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 << IPATH_AETH_CREDIT_SHIFT;
    }
    return cpu_to_be32(aeth);
}

struct ib_qp *ipath_create_qp(struct ib_pd *ibpd,
                  struct ib_qp_init_attr *init_attr,
                  struct ib_udata *udata)
{
    struct ipath_qp *qp;
    int err;
    struct ipath_swqe *swq = NULL;
    struct ipath_ibdev *dev;
    size_t sz;
    size_t sg_list_sz;
    struct ib_qp *ret;

    if (init_attr->create_flags) {
        ret = ERR_PTR(-EINVAL);
        goto bail;
    }

    if (init_attr->cap.max_send_sge > ib_ipath_max_sges ||
        init_attr->cap.max_send_wr > ib_ipath_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_ipath_max_sges ||
            init_attr->cap.max_recv_wr > ib_ipath_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_UC:
    case IB_QPT_RC:
    case IB_QPT_UD:
    case IB_QPT_SMI:
    case IB_QPT_GSI:
        sz = sizeof(struct ipath_sge) *
            init_attr->cap.max_send_sge +
            sizeof(struct ipath_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 ipath_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 = kmalloc(sz + sg_list_sz, GFP_KERNEL);
        if (!qp) {
            ret = ERR_PTR(-ENOMEM);
            goto bail_swq;
        }
        if (sg_list_sz && (init_attr->qp_type == IB_QPT_UD ||
            init_attr->qp_type == IB_QPT_SMI ||
            init_attr->qp_type == IB_QPT_GSI)) {
            qp->r_ud_sg_list = kmalloc(sg_list_sz, GFP_KERNEL);
            if (!qp->r_ud_sg_list) {
                ret = ERR_PTR(-ENOMEM);
                goto bail_qp;
            }
        } else
            qp->r_ud_sg_list = NULL;
        if (init_attr->srq) {
            sz = 0;
            qp->r_rq.size = 0;
            qp->r_rq.max_sge = 0;
            qp->r_rq.wq = NULL;
            init_attr->cap.max_recv_wr = 0;
            init_attr->cap.max_recv_sge = 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 ipath_rwqe);
            qp->r_rq.wq = vmalloc_user(sizeof(struct ipath_rwq) +
                          qp->r_rq.size * sz);
            if (!qp->r_rq.wq) {
                ret = ERR_PTR(-ENOMEM);
                goto bail_sg_list;
            }
        }

        /*
         * ib_create_qp() will initialize qp->ibqp
         * except for qp->ibqp.qp_num.
         */
        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);
        tasklet_init(&qp->s_task, ipath_do_send, (unsigned long)qp);
        INIT_LIST_HEAD(&qp->piowait);
        INIT_LIST_HEAD(&qp->timerwait);
        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 = IPATH_S_SIGNAL_REQ_WR;
        else
            qp->s_flags = 0;
        dev = to_idev(ibpd->device);
        err = ipath_alloc_qpn(&dev->qp_table, qp,
                      init_attr->qp_type);
        if (err) {
            ret = ERR_PTR(err);
            vfree(qp->r_rq.wq);
            goto bail_sg_list;
        }
        qp->ip = NULL;
        qp->s_tx = NULL;
        ipath_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 ipath_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 ipath_rwq) +
                qp->r_rq.size * sz;

            qp->ip =
                ipath_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_ipath_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, ipath_release_mmap_info);
    else
        vfree(qp->r_rq.wq);
    ipath_free_qp(&dev->qp_table, qp);
    free_qpn(&dev->qp_table, qp->ibqp.qp_num);
bail_sg_list:
    kfree(qp->r_ud_sg_list);
bail_qp:
    kfree(qp);
bail_swq:
    vfree(swq);
bail:
    return ret;
}

int ipath_destroy_qp(struct ib_qp *ibqp)
{
    struct ipath_qp *qp = to_iqp(ibqp);
    struct ipath_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->timerwait))
            list_del_init(&qp->timerwait);
        if (!list_empty(&qp->piowait))
            list_del_init(&qp->piowait);
        spin_unlock(&dev->pending_lock);
        qp->s_flags &= ~IPATH_S_ANY_WAIT;
        spin_unlock_irq(&qp->s_lock);
        /* Stop the sending tasklet */
        tasklet_kill(&qp->s_task);
        wait_event(qp->wait_dma, !atomic_read(&qp->s_dma_busy));
    } else
        spin_unlock_irq(&qp->s_lock);

    ipath_free_qp(&dev->qp_table, qp);

    if (qp->s_tx) {
        atomic_dec(&qp->refcount);
        if (qp->s_tx->txreq.flags & IPATH_SDMA_TXREQ_F_FREEBUF)
            kfree(qp->s_tx->txreq.map_addr);
        spin_lock_irq(&dev->pending_lock);
        list_add(&qp->s_tx->txreq.list, &dev->txreq_free);
        spin_unlock_irq(&dev->pending_lock);
        qp->s_tx = NULL;
    }

    wait_event(qp->wait, !atomic_read(&qp->refcount));

    /* all user's cleaned up, mark it available */
    free_qpn(&dev->qp_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, ipath_release_mmap_info);
    else
        vfree(qp->r_rq.wq);
    kfree(qp->r_ud_sg_list);
    vfree(qp->s_wq);
    kfree(qp);
    return 0;
}

int ipath_init_qp_table(struct ipath_ibdev *idev, int size)
{
    int i;
    int ret;

    idev->qp_table.last = 1;    /* QPN 0 and 1 are special. */
    idev->qp_table.max = size;
    idev->qp_table.nmaps = 1;
    idev->qp_table.table = kzalloc(size * sizeof(*idev->qp_table.table),
                       GFP_KERNEL);
    if (idev->qp_table.table == NULL) {
        ret = -ENOMEM;
        goto bail;
    }

    for (i = 0; i < ARRAY_SIZE(idev->qp_table.map); i++) {
        atomic_set(&idev->qp_table.map[i].n_free, BITS_PER_PAGE);
        idev->qp_table.map[i].page = NULL;
    }

    ret = 0;

bail:
    return ret;
}

void ipath_get_credit(struct ipath_qp *qp, u32 aeth)
{
    u32 credit = (aeth >> IPATH_AETH_CREDIT_SHIFT) & IPATH_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 == IPATH_AETH_CREDIT_INVAL)
        qp->s_lsn = (u32) -1;
    else if (qp->s_lsn != (u32) -1) {
        /* Compute new LSN (i.e., MSN + credit) */
        credit = (aeth + credit_table[credit]) & IPATH_MSN_MASK;
        if (ipath_cmp24(credit, qp->s_lsn) > 0)
            qp->s_lsn = credit;
    }

    /* Restart sending if it was blocked due to lack of credits. */
    if ((qp->s_flags & IPATH_S_WAIT_SSN_CREDIT) &&
        qp->s_cur != qp->s_head &&
        (qp->s_lsn == (u32) -1 ||
         ipath_cmp24(get_swqe_ptr(qp, qp->s_cur)->ssn,
             qp->s_lsn + 1) <= 0))
        ipath_schedule_send(qp);
}