ehca_reqs.c

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/*
 *  IBM eServer eHCA Infiniband device driver for Linux on POWER
 *
 *  post_send/recv, poll_cq, req_notify
 *
 *  Authors: Hoang-Nam Nguyen <[email protected]>
 *           Waleri Fomin <[email protected]>
 *           Joachim Fenkes <[email protected]>
 *           Reinhard Ernst <[email protected]>
 *
 *  Copyright (c) 2005 IBM Corporation
 *
 *  All rights reserved.
 *
 *  This source code is distributed under a dual license of GPL v2.0 and OpenIB
 *  BSD.
 *
 * OpenIB BSD License
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
 * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */


#include "ehca_classes.h"
#include "ehca_tools.h"
#include "ehca_qes.h"
#include "ehca_iverbs.h"
#include "hcp_if.h"
#include "hipz_fns.h"

/* in RC traffic, insert an empty RDMA READ every this many packets */
#define ACK_CIRC_THRESHOLD 2000000

static u64 replace_wr_id(u64 wr_id, u16 idx)
{
    u64 ret;

    ret = wr_id & ~QMAP_IDX_MASK;
    ret |= idx & QMAP_IDX_MASK;

    return ret;
}

static u16 get_app_wr_id(u64 wr_id)
{
    return wr_id & QMAP_IDX_MASK;
}

static inline int ehca_write_rwqe(struct ipz_queue *ipz_rqueue,
                  struct ehca_wqe *wqe_p,
                  struct ib_recv_wr *recv_wr,
                  u32 rq_map_idx)
{
    u8 cnt_ds;
    if (unlikely((recv_wr->num_sge < 0) ||
             (recv_wr->num_sge > ipz_rqueue->act_nr_of_sg))) {
        ehca_gen_err("Invalid number of WQE SGE. "
             "num_sqe=%x max_nr_of_sg=%x",
             recv_wr->num_sge, ipz_rqueue->act_nr_of_sg);
        return -EINVAL; /* invalid SG list length */
    }

    /* clear wqe header until sglist */
    memset(wqe_p, 0, offsetof(struct ehca_wqe, u.ud_av.sg_list));

    wqe_p->work_request_id = replace_wr_id(recv_wr->wr_id, rq_map_idx);
    wqe_p->nr_of_data_seg = recv_wr->num_sge;

    for (cnt_ds = 0; cnt_ds < recv_wr->num_sge; cnt_ds++) {
        wqe_p->u.all_rcv.sg_list[cnt_ds].vaddr =
            recv_wr->sg_list[cnt_ds].addr;
        wqe_p->u.all_rcv.sg_list[cnt_ds].lkey =
            recv_wr->sg_list[cnt_ds].lkey;
        wqe_p->u.all_rcv.sg_list[cnt_ds].length =
            recv_wr->sg_list[cnt_ds].length;
    }

    if (ehca_debug_level >= 3) {
        ehca_gen_dbg("RECEIVE WQE written into ipz_rqueue=%p",
                 ipz_rqueue);
        ehca_dmp(wqe_p, 16*(6 + wqe_p->nr_of_data_seg), "recv wqe");
    }

    return 0;
}

#if defined(DEBUG_GSI_SEND_WR)

/* need ib_mad struct */
#include <rdma/ib_mad.h>

static void trace_send_wr_ud(const struct ib_send_wr *send_wr)
{
    int idx;
    int j;
    while (send_wr) {
        struct ib_mad_hdr *mad_hdr = send_wr->wr.ud.mad_hdr;
        struct ib_sge *sge = send_wr->sg_list;
        ehca_gen_dbg("send_wr#%x wr_id=%lx num_sge=%x "
                 "send_flags=%x opcode=%x", idx, send_wr->wr_id,
                 send_wr->num_sge, send_wr->send_flags,
                 send_wr->opcode);
        if (mad_hdr) {
            ehca_gen_dbg("send_wr#%x mad_hdr base_version=%x "
                     "mgmt_class=%x class_version=%x method=%x "
                     "status=%x class_specific=%x tid=%lx "
                     "attr_id=%x resv=%x attr_mod=%x",
                     idx, mad_hdr->base_version,
                     mad_hdr->mgmt_class,
                     mad_hdr->class_version, mad_hdr->method,
                     mad_hdr->status, mad_hdr->class_specific,
                     mad_hdr->tid, mad_hdr->attr_id,
                     mad_hdr->resv,
                     mad_hdr->attr_mod);
        }
        for (j = 0; j < send_wr->num_sge; j++) {
            u8 *data = __va(sge->addr);
            ehca_gen_dbg("send_wr#%x sge#%x addr=%p length=%x "
                     "lkey=%x",
                     idx, j, data, sge->length, sge->lkey);
            /* assume length is n*16 */
            ehca_dmp(data, sge->length, "send_wr#%x sge#%x",
                 idx, j);
            sge++;
        } /* eof for j */
        idx++;
        send_wr = send_wr->next;
    } /* eof while send_wr */
}

#endif /* DEBUG_GSI_SEND_WR */

static inline int ehca_write_swqe(struct ehca_qp *qp,
                  struct ehca_wqe *wqe_p,
                  const struct ib_send_wr *send_wr,
                  u32 sq_map_idx,
                  int hidden)
{
    u32 idx;
    u64 dma_length;
    struct ehca_av *my_av;
    u32 remote_qkey = send_wr->wr.ud.remote_qkey;
    struct ehca_qmap_entry *qmap_entry = &qp->sq_map.map[sq_map_idx];

    if (unlikely((send_wr->num_sge < 0) ||
             (send_wr->num_sge > qp->ipz_squeue.act_nr_of_sg))) {
        ehca_gen_err("Invalid number of WQE SGE. "
             "num_sqe=%x max_nr_of_sg=%x",
             send_wr->num_sge, qp->ipz_squeue.act_nr_of_sg);
        return -EINVAL; /* invalid SG list length */
    }

    /* clear wqe header until sglist */
    memset(wqe_p, 0, offsetof(struct ehca_wqe, u.ud_av.sg_list));

    wqe_p->work_request_id = replace_wr_id(send_wr->wr_id, sq_map_idx);

    qmap_entry->app_wr_id = get_app_wr_id(send_wr->wr_id);
    qmap_entry->reported = 0;
    qmap_entry->cqe_req = 0;

    switch (send_wr->opcode) {
    case IB_WR_SEND:
    case IB_WR_SEND_WITH_IMM:
        wqe_p->optype = WQE_OPTYPE_SEND;
        break;
    case IB_WR_RDMA_WRITE:
    case IB_WR_RDMA_WRITE_WITH_IMM:
        wqe_p->optype = WQE_OPTYPE_RDMAWRITE;
        break;
    case IB_WR_RDMA_READ:
        wqe_p->optype = WQE_OPTYPE_RDMAREAD;
        break;
    default:
        ehca_gen_err("Invalid opcode=%x", send_wr->opcode);
        return -EINVAL; /* invalid opcode */
    }

    wqe_p->wqef = (send_wr->opcode) & WQEF_HIGH_NIBBLE;

    wqe_p->wr_flag = 0;

    if ((send_wr->send_flags & IB_SEND_SIGNALED ||
        qp->init_attr.sq_sig_type == IB_SIGNAL_ALL_WR)
        && !hidden) {
        wqe_p->wr_flag |= WQE_WRFLAG_REQ_SIGNAL_COM;
        qmap_entry->cqe_req = 1;
    }

    if (send_wr->opcode == IB_WR_SEND_WITH_IMM ||
        send_wr->opcode == IB_WR_RDMA_WRITE_WITH_IMM) {
        /* this might not work as long as HW does not support it */
        wqe_p->immediate_data = be32_to_cpu(send_wr->ex.imm_data);
        wqe_p->wr_flag |= WQE_WRFLAG_IMM_DATA_PRESENT;
    }

    wqe_p->nr_of_data_seg = send_wr->num_sge;

    switch (qp->qp_type) {
    case IB_QPT_SMI:
    case IB_QPT_GSI:
        /* no break is intential here */
    case IB_QPT_UD:
        /* IB 1.2 spec C10-15 compliance */
        if (send_wr->wr.ud.remote_qkey & 0x80000000)
            remote_qkey = qp->qkey;

        wqe_p->destination_qp_number = send_wr->wr.ud.remote_qpn << 8;
        wqe_p->local_ee_context_qkey = remote_qkey;
        if (unlikely(!send_wr->wr.ud.ah)) {
            ehca_gen_err("wr.ud.ah is NULL. qp=%p", qp);
            return -EINVAL;
        }
        if (unlikely(send_wr->wr.ud.remote_qpn == 0)) {
            ehca_gen_err("dest QP# is 0. qp=%x", qp->real_qp_num);
            return -EINVAL;
        }
        my_av = container_of(send_wr->wr.ud.ah, struct ehca_av, ib_ah);
        wqe_p->u.ud_av.ud_av = my_av->av;

        /*
         * omitted check of IB_SEND_INLINE
         * since HW does not support it
         */
        for (idx = 0; idx < send_wr->num_sge; idx++) {
            wqe_p->u.ud_av.sg_list[idx].vaddr =
                send_wr->sg_list[idx].addr;
            wqe_p->u.ud_av.sg_list[idx].lkey =
                send_wr->sg_list[idx].lkey;
            wqe_p->u.ud_av.sg_list[idx].length =
                send_wr->sg_list[idx].length;
        } /* eof for idx */
        if (qp->qp_type == IB_QPT_SMI ||
            qp->qp_type == IB_QPT_GSI)
            wqe_p->u.ud_av.ud_av.pmtu = 1;
        if (qp->qp_type == IB_QPT_GSI) {
            wqe_p->pkeyi = send_wr->wr.ud.pkey_index;
#ifdef DEBUG_GSI_SEND_WR
            trace_send_wr_ud(send_wr);
#endif /* DEBUG_GSI_SEND_WR */
        }
        break;

    case IB_QPT_UC:
        if (send_wr->send_flags & IB_SEND_FENCE)
            wqe_p->wr_flag |= WQE_WRFLAG_FENCE;
        /* no break is intentional here */
    case IB_QPT_RC:
        /* TODO: atomic not implemented */
        wqe_p->u.nud.remote_virtual_address =
            send_wr->wr.rdma.remote_addr;
        wqe_p->u.nud.rkey = send_wr->wr.rdma.rkey;

        /*
         * omitted checking of IB_SEND_INLINE
         * since HW does not support it
         */
        dma_length = 0;
        for (idx = 0; idx < send_wr->num_sge; idx++) {
            wqe_p->u.nud.sg_list[idx].vaddr =
                send_wr->sg_list[idx].addr;
            wqe_p->u.nud.sg_list[idx].lkey =
                send_wr->sg_list[idx].lkey;
            wqe_p->u.nud.sg_list[idx].length =
                send_wr->sg_list[idx].length;
            dma_length += send_wr->sg_list[idx].length;
        } /* eof idx */
        wqe_p->u.nud.atomic_1st_op_dma_len = dma_length;

        /* unsolicited ack circumvention */
        if (send_wr->opcode == IB_WR_RDMA_READ) {
            /* on RDMA read, switch on and reset counters */
            qp->message_count = qp->packet_count = 0;
            qp->unsol_ack_circ = 1;
        } else
            /* else estimate #packets */
            qp->packet_count += (dma_length >> qp->mtu_shift) + 1;

        break;

    default:
        ehca_gen_err("Invalid qptype=%x", qp->qp_type);
        return -EINVAL;
    }

    if (ehca_debug_level >= 3) {
        ehca_gen_dbg("SEND WQE written into queue qp=%p ", qp);
        ehca_dmp( wqe_p, 16*(6 + wqe_p->nr_of_data_seg), "send wqe");
    }
    return 0;
}

/* map_ib_wc_status converts raw cqe_status to ib_wc_status */
static inline void map_ib_wc_status(u32 cqe_status,
                    enum ib_wc_status *wc_status)
{
    if (unlikely(cqe_status & WC_STATUS_ERROR_BIT)) {
        switch (cqe_status & 0x3F) {
        case 0x01:
        case 0x21:
            *wc_status = IB_WC_LOC_LEN_ERR;
            break;
        case 0x02:
        case 0x22:
            *wc_status = IB_WC_LOC_QP_OP_ERR;
            break;
        case 0x03:
        case 0x23:
            *wc_status = IB_WC_LOC_EEC_OP_ERR;
            break;
        case 0x04:
        case 0x24:
            *wc_status = IB_WC_LOC_PROT_ERR;
            break;
        case 0x05:
        case 0x25:
            *wc_status = IB_WC_WR_FLUSH_ERR;
            break;
        case 0x06:
            *wc_status = IB_WC_MW_BIND_ERR;
            break;
        case 0x07: /* remote error - look into bits 20:24 */
            switch ((cqe_status
                 & WC_STATUS_REMOTE_ERROR_FLAGS) >> 11) {
            case 0x0:
                /*
                 * PSN Sequence Error!
                 * couldn't find a matching status!
                 */
                *wc_status = IB_WC_GENERAL_ERR;
                break;
            case 0x1:
                *wc_status = IB_WC_REM_INV_REQ_ERR;
                break;
            case 0x2:
                *wc_status = IB_WC_REM_ACCESS_ERR;
                break;
            case 0x3:
                *wc_status = IB_WC_REM_OP_ERR;
                break;
            case 0x4:
                *wc_status = IB_WC_REM_INV_RD_REQ_ERR;
                break;
            }
            break;
        case 0x08:
            *wc_status = IB_WC_RETRY_EXC_ERR;
            break;
        case 0x09:
            *wc_status = IB_WC_RNR_RETRY_EXC_ERR;
            break;
        case 0x0A:
        case 0x2D:
            *wc_status = IB_WC_REM_ABORT_ERR;
            break;
        case 0x0B:
        case 0x2E:
            *wc_status = IB_WC_INV_EECN_ERR;
            break;
        case 0x0C:
        case 0x2F:
            *wc_status = IB_WC_INV_EEC_STATE_ERR;
            break;
        case 0x0D:
            *wc_status = IB_WC_BAD_RESP_ERR;
            break;
        case 0x10:
            /* WQE purged */
            *wc_status = IB_WC_WR_FLUSH_ERR;
            break;
        default:
            *wc_status = IB_WC_FATAL_ERR;

        }
    } else
        *wc_status = IB_WC_SUCCESS;
}

static inline int post_one_send(struct ehca_qp *my_qp,
             struct ib_send_wr *cur_send_wr,
             int hidden)
{
    struct ehca_wqe *wqe_p;
    int ret;
    u32 sq_map_idx;
    u64 start_offset = my_qp->ipz_squeue.current_q_offset;

    /* get pointer next to free WQE */
    wqe_p = ipz_qeit_get_inc(&my_qp->ipz_squeue);
    if (unlikely(!wqe_p)) {
        /* too many posted work requests: queue overflow */
        ehca_err(my_qp->ib_qp.device, "Too many posted WQEs "
             "qp_num=%x", my_qp->ib_qp.qp_num);
        return -ENOMEM;
    }

    /*
     * Get the index of the WQE in the send queue. The same index is used
     * for writing into the sq_map.
     */
    sq_map_idx = start_offset / my_qp->ipz_squeue.qe_size;

    /* write a SEND WQE into the QUEUE */
    ret = ehca_write_swqe(my_qp, wqe_p, cur_send_wr, sq_map_idx, hidden);
    /*
     * if something failed,
     * reset the free entry pointer to the start value
     */
    if (unlikely(ret)) {
        my_qp->ipz_squeue.current_q_offset = start_offset;
        ehca_err(my_qp->ib_qp.device, "Could not write WQE "
             "qp_num=%x", my_qp->ib_qp.qp_num);
        return -EINVAL;
    }

    return 0;
}

int ehca_post_send(struct ib_qp *qp,
           struct ib_send_wr *send_wr,
           struct ib_send_wr **bad_send_wr)
{
    struct ehca_qp *my_qp = container_of(qp, struct ehca_qp, ib_qp);
    int wqe_cnt = 0;
    int ret = 0;
    unsigned long flags;

    /* Reject WR if QP is in RESET, INIT or RTR state */
    if (unlikely(my_qp->state < IB_QPS_RTS)) {
        ehca_err(qp->device, "Invalid QP state  qp_state=%d qpn=%x",
             my_qp->state, qp->qp_num);
        ret = -EINVAL;
        goto out;
    }

    /* LOCK the QUEUE */
    spin_lock_irqsave(&my_qp->spinlock_s, flags);

    /* Send an empty extra RDMA read if:
     *  1) there has been an RDMA read on this connection before
     *  2) no RDMA read occurred for ACK_CIRC_THRESHOLD link packets
     *  3) we can be sure that any previous extra RDMA read has been
     *     processed so we don't overflow the SQ
     */
    if (unlikely(my_qp->unsol_ack_circ &&
             my_qp->packet_count > ACK_CIRC_THRESHOLD &&
             my_qp->message_count > my_qp->init_attr.cap.max_send_wr)) {
        /* insert an empty RDMA READ to fix up the remote QP state */
        struct ib_send_wr circ_wr;
        memset(&circ_wr, 0, sizeof(circ_wr));
        circ_wr.opcode = IB_WR_RDMA_READ;
        post_one_send(my_qp, &circ_wr, 1); /* ignore retcode */
        wqe_cnt++;
        ehca_dbg(qp->device, "posted circ wr  qp_num=%x", qp->qp_num);
        my_qp->message_count = my_qp->packet_count = 0;
    }

    /* loop processes list of send reqs */
    while (send_wr) {
        ret = post_one_send(my_qp, send_wr, 0);
        if (unlikely(ret)) {
            goto post_send_exit0;
        }
        wqe_cnt++;
        send_wr = send_wr->next;
    }

post_send_exit0:
    iosync(); /* serialize GAL register access */
    hipz_update_sqa(my_qp, wqe_cnt);
    if (unlikely(ret || ehca_debug_level >= 2))
        ehca_dbg(qp->device, "ehca_qp=%p qp_num=%x wqe_cnt=%d ret=%i",
             my_qp, qp->qp_num, wqe_cnt, ret);
    my_qp->message_count += wqe_cnt;
    spin_unlock_irqrestore(&my_qp->spinlock_s, flags);

out:
    if (ret)
        *bad_send_wr = send_wr;
    return ret;
}

static int internal_post_recv(struct ehca_qp *my_qp,
                  struct ib_device *dev,
                  struct ib_recv_wr *recv_wr,
                  struct ib_recv_wr **bad_recv_wr)
{
    struct ehca_wqe *wqe_p;
    int wqe_cnt = 0;
    int ret = 0;
    u32 rq_map_idx;
    unsigned long flags;
    struct ehca_qmap_entry *qmap_entry;

    if (unlikely(!HAS_RQ(my_qp))) {
        ehca_err(dev, "QP has no RQ  ehca_qp=%p qp_num=%x ext_type=%d",
             my_qp, my_qp->real_qp_num, my_qp->ext_type);
        ret = -ENODEV;
        goto out;
    }

    /* LOCK the QUEUE */
    spin_lock_irqsave(&my_qp->spinlock_r, flags);

    /* loop processes list of recv reqs */
    while (recv_wr) {
        u64 start_offset = my_qp->ipz_rqueue.current_q_offset;
        /* get pointer next to free WQE */
        wqe_p = ipz_qeit_get_inc(&my_qp->ipz_rqueue);
        if (unlikely(!wqe_p)) {
            /* too many posted work requests: queue overflow */
            ret = -ENOMEM;
            ehca_err(dev, "Too many posted WQEs "
                "qp_num=%x", my_qp->real_qp_num);
            goto post_recv_exit0;
        }
        /*
         * Get the index of the WQE in the recv queue. The same index
         * is used for writing into the rq_map.
         */
        rq_map_idx = start_offset / my_qp->ipz_rqueue.qe_size;

        /* write a RECV WQE into the QUEUE */
        ret = ehca_write_rwqe(&my_qp->ipz_rqueue, wqe_p, recv_wr,
                rq_map_idx);
        /*
         * if something failed,
         * reset the free entry pointer to the start value
         */
        if (unlikely(ret)) {
            my_qp->ipz_rqueue.current_q_offset = start_offset;
            ret = -EINVAL;
            ehca_err(dev, "Could not write WQE "
                "qp_num=%x", my_qp->real_qp_num);
            goto post_recv_exit0;
        }

        qmap_entry = &my_qp->rq_map.map[rq_map_idx];
        qmap_entry->app_wr_id = get_app_wr_id(recv_wr->wr_id);
        qmap_entry->reported = 0;
        qmap_entry->cqe_req = 1;

        wqe_cnt++;
        recv_wr = recv_wr->next;
    } /* eof for recv_wr */

post_recv_exit0:
    iosync(); /* serialize GAL register access */
    hipz_update_rqa(my_qp, wqe_cnt);
    if (unlikely(ret || ehca_debug_level >= 2))
        ehca_dbg(dev, "ehca_qp=%p qp_num=%x wqe_cnt=%d ret=%i",
             my_qp, my_qp->real_qp_num, wqe_cnt, ret);
    spin_unlock_irqrestore(&my_qp->spinlock_r, flags);

out:
    if (ret)
        *bad_recv_wr = recv_wr;

    return ret;
}

int ehca_post_recv(struct ib_qp *qp,
           struct ib_recv_wr *recv_wr,
           struct ib_recv_wr **bad_recv_wr)
{
    struct ehca_qp *my_qp = container_of(qp, struct ehca_qp, ib_qp);

    /* Reject WR if QP is in RESET state */
    if (unlikely(my_qp->state == IB_QPS_RESET)) {
        ehca_err(qp->device, "Invalid QP state  qp_state=%d qpn=%x",
             my_qp->state, qp->qp_num);
        *bad_recv_wr = recv_wr;
        return -EINVAL;
    }

    return internal_post_recv(my_qp, qp->device, recv_wr, bad_recv_wr);
}

int ehca_post_srq_recv(struct ib_srq *srq,
               struct ib_recv_wr *recv_wr,
               struct ib_recv_wr **bad_recv_wr)
{
    return internal_post_recv(container_of(srq, struct ehca_qp, ib_srq),
                  srq->device, recv_wr, bad_recv_wr);
}

/*
 * ib_wc_opcode table converts ehca wc opcode to ib
 * Since we use zero to indicate invalid opcode, the actual ib opcode must
 * be decremented!!!
 */
static const u8 ib_wc_opcode[255] = {
    [0x01] = IB_WC_RECV+1,
    [0x02] = IB_WC_RECV_RDMA_WITH_IMM+1,
    [0x04] = IB_WC_BIND_MW+1,
    [0x08] = IB_WC_FETCH_ADD+1,
    [0x10] = IB_WC_COMP_SWAP+1,
    [0x20] = IB_WC_RDMA_WRITE+1,
    [0x40] = IB_WC_RDMA_READ+1,
    [0x80] = IB_WC_SEND+1
};

/* internal function to poll one entry of cq */
static inline int ehca_poll_cq_one(struct ib_cq *cq, struct ib_wc *wc)
{
    int ret = 0, qmap_tail_idx;
    struct ehca_cq *my_cq = container_of(cq, struct ehca_cq, ib_cq);
    struct ehca_cqe *cqe;
    struct ehca_qp *my_qp;
    struct ehca_qmap_entry *qmap_entry;
    struct ehca_queue_map *qmap;
    int cqe_count = 0, is_error;

repoll:
    cqe = (struct ehca_cqe *)
        ipz_qeit_get_inc_valid(&my_cq->ipz_queue);
    if (!cqe) {
        ret = -EAGAIN;
        if (ehca_debug_level >= 3)
            ehca_dbg(cq->device, "Completion queue is empty  "
                 "my_cq=%p cq_num=%x", my_cq, my_cq->cq_number);
        goto poll_cq_one_exit0;
    }

    /* prevents loads being reordered across this point */
    rmb();

    cqe_count++;
    if (unlikely(cqe->status & WC_STATUS_PURGE_BIT)) {
        struct ehca_qp *qp;
        int purgeflag;
        unsigned long flags;

        qp = ehca_cq_get_qp(my_cq, cqe->local_qp_number);
        if (!qp) {
            ehca_err(cq->device, "cq_num=%x qp_num=%x "
                 "could not find qp -> ignore cqe",
                 my_cq->cq_number, cqe->local_qp_number);
            ehca_dmp(cqe, 64, "cq_num=%x qp_num=%x",
                 my_cq->cq_number, cqe->local_qp_number);
            /* ignore this purged cqe */
            goto repoll;
        }
        spin_lock_irqsave(&qp->spinlock_s, flags);
        purgeflag = qp->sqerr_purgeflag;
        spin_unlock_irqrestore(&qp->spinlock_s, flags);

        if (purgeflag) {
            ehca_dbg(cq->device,
                 "Got CQE with purged bit qp_num=%x src_qp=%x",
                 cqe->local_qp_number, cqe->remote_qp_number);
            if (ehca_debug_level >= 2)
                ehca_dmp(cqe, 64, "qp_num=%x src_qp=%x",
                     cqe->local_qp_number,
                     cqe->remote_qp_number);
            /*
             * ignore this to avoid double cqes of bad wqe
             * that caused sqe and turn off purge flag
             */
            qp->sqerr_purgeflag = 0;
            goto repoll;
        }
    }

    is_error = cqe->status & WC_STATUS_ERROR_BIT;

    /* trace error CQEs if debug_level >= 1, trace all CQEs if >= 3 */
    if (unlikely(ehca_debug_level >= 3 || (ehca_debug_level && is_error))) {
        ehca_dbg(cq->device,
             "Received %sCOMPLETION ehca_cq=%p cq_num=%x -----",
             is_error ? "ERROR " : "", my_cq, my_cq->cq_number);
        ehca_dmp(cqe, 64, "ehca_cq=%p cq_num=%x",
             my_cq, my_cq->cq_number);
        ehca_dbg(cq->device,
             "ehca_cq=%p cq_num=%x -------------------------",
             my_cq, my_cq->cq_number);
    }

    read_lock(&ehca_qp_idr_lock);
    my_qp = idr_find(&ehca_qp_idr, cqe->qp_token);
    read_unlock(&ehca_qp_idr_lock);
    if (!my_qp)
        goto repoll;
    wc->qp = &my_qp->ib_qp;

    qmap_tail_idx = get_app_wr_id(cqe->work_request_id);
    if (!(cqe->w_completion_flags & WC_SEND_RECEIVE_BIT))
        /* We got a send completion. */
        qmap = &my_qp->sq_map;
    else
        /* We got a receive completion. */
        qmap = &my_qp->rq_map;

    /* advance the tail pointer */
    qmap->tail = qmap_tail_idx;

    if (is_error) {
        /*
         * set left_to_poll to 0 because in error state, we will not
         * get any additional CQEs
         */
        my_qp->sq_map.next_wqe_idx = next_index(my_qp->sq_map.tail,
                            my_qp->sq_map.entries);
        my_qp->sq_map.left_to_poll = 0;
        ehca_add_to_err_list(my_qp, 1);

        my_qp->rq_map.next_wqe_idx = next_index(my_qp->rq_map.tail,
                            my_qp->rq_map.entries);
        my_qp->rq_map.left_to_poll = 0;
        if (HAS_RQ(my_qp))
            ehca_add_to_err_list(my_qp, 0);
    }

    qmap_entry = &qmap->map[qmap_tail_idx];
    if (qmap_entry->reported) {
        ehca_warn(cq->device, "Double cqe on qp_num=%#x",
                my_qp->real_qp_num);
        /* found a double cqe, discard it and read next one */
        goto repoll;
    }

    wc->wr_id = replace_wr_id(cqe->work_request_id, qmap_entry->app_wr_id);
    qmap_entry->reported = 1;

    /* if left_to_poll is decremented to 0, add the QP to the error list */
    if (qmap->left_to_poll > 0) {
        qmap->left_to_poll--;
        if ((my_qp->sq_map.left_to_poll == 0) &&
                (my_qp->rq_map.left_to_poll == 0)) {
            ehca_add_to_err_list(my_qp, 1);
            if (HAS_RQ(my_qp))
                ehca_add_to_err_list(my_qp, 0);
        }
    }

    /* eval ib_wc_opcode */
    wc->opcode = ib_wc_opcode[cqe->optype]-1;
    if (unlikely(wc->opcode == -1)) {
        ehca_err(cq->device, "Invalid cqe->OPType=%x cqe->status=%x "
             "ehca_cq=%p cq_num=%x",
             cqe->optype, cqe->status, my_cq, my_cq->cq_number);
        /* dump cqe for other infos */
        ehca_dmp(cqe, 64, "ehca_cq=%p cq_num=%x",
             my_cq, my_cq->cq_number);
        /* update also queue adder to throw away this entry!!! */
        goto repoll;
    }

    /* eval ib_wc_status */
    if (unlikely(is_error)) {
        /* complete with errors */
        map_ib_wc_status(cqe->status, &wc->status);
        wc->vendor_err = wc->status;
    } else
        wc->status = IB_WC_SUCCESS;

    wc->byte_len = cqe->nr_bytes_transferred;
    wc->pkey_index = cqe->pkey_index;
    wc->slid = cqe->rlid;
    wc->dlid_path_bits = cqe->dlid;
    wc->src_qp = cqe->remote_qp_number;
    /*
     * HW has "Immed data present" and "GRH present" in bits 6 and 5.
     * SW defines those in bits 1 and 0, so we can just shift and mask.
     */
    wc->wc_flags = (cqe->w_completion_flags >> 5) & 3;
    wc->ex.imm_data = cpu_to_be32(cqe->immediate_data);
    wc->sl = cqe->service_level;

poll_cq_one_exit0:
    if (cqe_count > 0)
        hipz_update_feca(my_cq, cqe_count);

    return ret;
}

static int generate_flush_cqes(struct ehca_qp *my_qp, struct ib_cq *cq,
                   struct ib_wc *wc, int num_entries,
                   struct ipz_queue *ipz_queue, int on_sq)
{
    int nr = 0;
    struct ehca_wqe *wqe;
    u64 offset;
    struct ehca_queue_map *qmap;
    struct ehca_qmap_entry *qmap_entry;

    if (on_sq)
        qmap = &my_qp->sq_map;
    else
        qmap = &my_qp->rq_map;

    qmap_entry = &qmap->map[qmap->next_wqe_idx];

    while ((nr < num_entries) && (qmap_entry->reported == 0)) {
        /* generate flush CQE */

        memset(wc, 0, sizeof(*wc));

        offset = qmap->next_wqe_idx * ipz_queue->qe_size;
        wqe = (struct ehca_wqe *)ipz_qeit_calc(ipz_queue, offset);
        if (!wqe) {
            ehca_err(cq->device, "Invalid wqe offset=%#llx on "
                 "qp_num=%#x", offset, my_qp->real_qp_num);
            return nr;
        }

        wc->wr_id = replace_wr_id(wqe->work_request_id,
                      qmap_entry->app_wr_id);

        if (on_sq) {
            switch (wqe->optype) {
            case WQE_OPTYPE_SEND:
                wc->opcode = IB_WC_SEND;
                break;
            case WQE_OPTYPE_RDMAWRITE:
                wc->opcode = IB_WC_RDMA_WRITE;
                break;
            case WQE_OPTYPE_RDMAREAD:
                wc->opcode = IB_WC_RDMA_READ;
                break;
            default:
                ehca_err(cq->device, "Invalid optype=%x",
                        wqe->optype);
                return nr;
            }
        } else
            wc->opcode = IB_WC_RECV;

        if (wqe->wr_flag & WQE_WRFLAG_IMM_DATA_PRESENT) {
            wc->ex.imm_data = wqe->immediate_data;
            wc->wc_flags |= IB_WC_WITH_IMM;
        }

        wc->status = IB_WC_WR_FLUSH_ERR;

        wc->qp = &my_qp->ib_qp;

        /* mark as reported and advance next_wqe pointer */
        qmap_entry->reported = 1;
        qmap->next_wqe_idx = next_index(qmap->next_wqe_idx,
                        qmap->entries);
        qmap_entry = &qmap->map[qmap->next_wqe_idx];

        wc++; nr++;
    }

    return nr;

}

int ehca_poll_cq(struct ib_cq *cq, int num_entries, struct ib_wc *wc)
{
    struct ehca_cq *my_cq = container_of(cq, struct ehca_cq, ib_cq);
    int nr;
    struct ehca_qp *err_qp;
    struct ib_wc *current_wc = wc;
    int ret = 0;
    unsigned long flags;
    int entries_left = num_entries;

    if (num_entries < 1) {
        ehca_err(cq->device, "Invalid num_entries=%d ehca_cq=%p "
             "cq_num=%x", num_entries, my_cq, my_cq->cq_number);
        ret = -EINVAL;
        goto poll_cq_exit0;
    }

    spin_lock_irqsave(&my_cq->spinlock, flags);

    /* generate flush cqes for send queues */
    list_for_each_entry(err_qp, &my_cq->sqp_err_list, sq_err_node) {
        nr = generate_flush_cqes(err_qp, cq, current_wc, entries_left,
                &err_qp->ipz_squeue, 1);
        entries_left -= nr;
        current_wc += nr;

        if (entries_left == 0)
            break;
    }

    /* generate flush cqes for receive queues */
    list_for_each_entry(err_qp, &my_cq->rqp_err_list, rq_err_node) {
        nr = generate_flush_cqes(err_qp, cq, current_wc, entries_left,
                &err_qp->ipz_rqueue, 0);
        entries_left -= nr;
        current_wc += nr;

        if (entries_left == 0)
            break;
    }

    for (nr = 0; nr < entries_left; nr++) {
        ret = ehca_poll_cq_one(cq, current_wc);
        if (ret)
            break;
        current_wc++;
    } /* eof for nr */
    entries_left -= nr;

    spin_unlock_irqrestore(&my_cq->spinlock, flags);
    if (ret == -EAGAIN  || !ret)
        ret = num_entries - entries_left;

poll_cq_exit0:
    return ret;
}

int ehca_req_notify_cq(struct ib_cq *cq, enum ib_cq_notify_flags notify_flags)
{
    struct ehca_cq *my_cq = container_of(cq, struct ehca_cq, ib_cq);
    int ret = 0;

    switch (notify_flags & IB_CQ_SOLICITED_MASK) {
    case IB_CQ_SOLICITED:
        hipz_set_cqx_n0(my_cq, 1);
        break;
    case IB_CQ_NEXT_COMP:
        hipz_set_cqx_n1(my_cq, 1);
        break;
    default:
        return -EINVAL;
    }

    if (notify_flags & IB_CQ_REPORT_MISSED_EVENTS) {
        unsigned long spl_flags;
        spin_lock_irqsave(&my_cq->spinlock, spl_flags);
        ret = ipz_qeit_is_valid(&my_cq->ipz_queue);
        spin_unlock_irqrestore(&my_cq->spinlock, spl_flags);
    }

    return ret;
}