networking: make skb_put & friends return void pointers

[mirror_ubuntu-artful-kernel.git] / drivers / infiniband / hw / cxgb4 / cq.c

/*
 * Copyright (c) 2009-2010 Chelsio, 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 "iw_cxgb4.h"

static int destroy_cq(struct c4iw_rdev *rdev, struct t4_cq *cq,
                      struct c4iw_dev_ucontext *uctx, struct sk_buff *skb)
{
        struct fw_ri_res_wr *res_wr;
        struct fw_ri_res *res;
        int wr_len;
        struct c4iw_wr_wait wr_wait;
        int ret;

        wr_len = sizeof *res_wr + sizeof *res;
        set_wr_txq(skb, CPL_PRIORITY_CONTROL, 0);

        res_wr = __skb_put(skb, wr_len);
        memset(res_wr, 0, wr_len);
        res_wr->op_nres = cpu_to_be32(
                        FW_WR_OP_V(FW_RI_RES_WR) |
                        FW_RI_RES_WR_NRES_V(1) |
                        FW_WR_COMPL_F);
        res_wr->len16_pkd = cpu_to_be32(DIV_ROUND_UP(wr_len, 16));
        res_wr->cookie = (uintptr_t)&wr_wait;
        res = res_wr->res;
        res->u.cq.restype = FW_RI_RES_TYPE_CQ;
        res->u.cq.op = FW_RI_RES_OP_RESET;
        res->u.cq.iqid = cpu_to_be32(cq->cqid);

        c4iw_init_wr_wait(&wr_wait);
        ret = c4iw_ofld_send(rdev, skb);
        if (!ret) {
                ret = c4iw_wait_for_reply(rdev, &wr_wait, 0, 0, __func__);
        }

        kfree(cq->sw_queue);
        dma_free_coherent(&(rdev->lldi.pdev->dev),
                          cq->memsize, cq->queue,
                          dma_unmap_addr(cq, mapping));
        c4iw_put_cqid(rdev, cq->cqid, uctx);
        return ret;
}

static int create_cq(struct c4iw_rdev *rdev, struct t4_cq *cq,
                     struct c4iw_dev_ucontext *uctx)
{
        struct fw_ri_res_wr *res_wr;
        struct fw_ri_res *res;
        int wr_len;
        int user = (uctx != &rdev->uctx);
        struct c4iw_wr_wait wr_wait;
        int ret;
        struct sk_buff *skb;

        cq->cqid = c4iw_get_cqid(rdev, uctx);
        if (!cq->cqid) {
                ret = -ENOMEM;
                goto err1;
        }

        if (!user) {
                cq->sw_queue = kzalloc(cq->memsize, GFP_KERNEL);
                if (!cq->sw_queue) {
                        ret = -ENOMEM;
                        goto err2;
                }
        }
        cq->queue = dma_alloc_coherent(&rdev->lldi.pdev->dev, cq->memsize,
                                       &cq->dma_addr, GFP_KERNEL);
        if (!cq->queue) {
                ret = -ENOMEM;
                goto err3;
        }
        dma_unmap_addr_set(cq, mapping, cq->dma_addr);
        memset(cq->queue, 0, cq->memsize);

        /* build fw_ri_res_wr */
        wr_len = sizeof *res_wr + sizeof *res;

        skb = alloc_skb(wr_len, GFP_KERNEL);
        if (!skb) {
                ret = -ENOMEM;
                goto err4;
        }
        set_wr_txq(skb, CPL_PRIORITY_CONTROL, 0);

        res_wr = __skb_put(skb, wr_len);
        memset(res_wr, 0, wr_len);
        res_wr->op_nres = cpu_to_be32(
                        FW_WR_OP_V(FW_RI_RES_WR) |
                        FW_RI_RES_WR_NRES_V(1) |
                        FW_WR_COMPL_F);
        res_wr->len16_pkd = cpu_to_be32(DIV_ROUND_UP(wr_len, 16));
        res_wr->cookie = (uintptr_t)&wr_wait;
        res = res_wr->res;
        res->u.cq.restype = FW_RI_RES_TYPE_CQ;
        res->u.cq.op = FW_RI_RES_OP_WRITE;
        res->u.cq.iqid = cpu_to_be32(cq->cqid);
        res->u.cq.iqandst_to_iqandstindex = cpu_to_be32(
                        FW_RI_RES_WR_IQANUS_V(0) |
                        FW_RI_RES_WR_IQANUD_V(1) |
                        FW_RI_RES_WR_IQANDST_F |
                        FW_RI_RES_WR_IQANDSTINDEX_V(
                                rdev->lldi.ciq_ids[cq->vector]));
        res->u.cq.iqdroprss_to_iqesize = cpu_to_be16(
                        FW_RI_RES_WR_IQDROPRSS_F |
                        FW_RI_RES_WR_IQPCIECH_V(2) |
                        FW_RI_RES_WR_IQINTCNTTHRESH_V(0) |
                        FW_RI_RES_WR_IQO_F |
                        FW_RI_RES_WR_IQESIZE_V(1));
        res->u.cq.iqsize = cpu_to_be16(cq->size);
        res->u.cq.iqaddr = cpu_to_be64(cq->dma_addr);

        c4iw_init_wr_wait(&wr_wait);

        ret = c4iw_ofld_send(rdev, skb);
        if (ret)
                goto err4;
        pr_debug("%s wait_event wr_wait %p\n", __func__, &wr_wait);
        ret = c4iw_wait_for_reply(rdev, &wr_wait, 0, 0, __func__);
        if (ret)
                goto err4;

        cq->gen = 1;
        cq->gts = rdev->lldi.gts_reg;
        cq->rdev = rdev;

        cq->bar2_va = c4iw_bar2_addrs(rdev, cq->cqid, T4_BAR2_QTYPE_INGRESS,
                                      &cq->bar2_qid,
                                      user ? &cq->bar2_pa : NULL);
        if (user && !cq->bar2_pa) {
                pr_warn("%s: cqid %u not in BAR2 range\n",
                        pci_name(rdev->lldi.pdev), cq->cqid);
                ret = -EINVAL;
                goto err4;
        }
        return 0;
err4:
        dma_free_coherent(&rdev->lldi.pdev->dev, cq->memsize, cq->queue,
                          dma_unmap_addr(cq, mapping));
err3:
        kfree(cq->sw_queue);
err2:
        c4iw_put_cqid(rdev, cq->cqid, uctx);
err1:
        return ret;
}

static void insert_recv_cqe(struct t4_wq *wq, struct t4_cq *cq)
{
        struct t4_cqe cqe;

        pr_debug("%s wq %p cq %p sw_cidx %u sw_pidx %u\n", __func__,
                 wq, cq, cq->sw_cidx, cq->sw_pidx);
        memset(&cqe, 0, sizeof(cqe));
        cqe.header = cpu_to_be32(CQE_STATUS_V(T4_ERR_SWFLUSH) |
                                 CQE_OPCODE_V(FW_RI_SEND) |
                                 CQE_TYPE_V(0) |
                                 CQE_SWCQE_V(1) |
                                 CQE_QPID_V(wq->sq.qid));
        cqe.bits_type_ts = cpu_to_be64(CQE_GENBIT_V((u64)cq->gen));
        cq->sw_queue[cq->sw_pidx] = cqe;
        t4_swcq_produce(cq);
}

int c4iw_flush_rq(struct t4_wq *wq, struct t4_cq *cq, int count)
{
        int flushed = 0;
        int in_use = wq->rq.in_use - count;

        BUG_ON(in_use < 0);
        pr_debug("%s wq %p cq %p rq.in_use %u skip count %u\n", __func__,
                 wq, cq, wq->rq.in_use, count);
        while (in_use--) {
                insert_recv_cqe(wq, cq);
                flushed++;
        }
        return flushed;
}

static void insert_sq_cqe(struct t4_wq *wq, struct t4_cq *cq,
                          struct t4_swsqe *swcqe)
{
        struct t4_cqe cqe;

        pr_debug("%s wq %p cq %p sw_cidx %u sw_pidx %u\n", __func__,
                 wq, cq, cq->sw_cidx, cq->sw_pidx);
        memset(&cqe, 0, sizeof(cqe));
        cqe.header = cpu_to_be32(CQE_STATUS_V(T4_ERR_SWFLUSH) |
                                 CQE_OPCODE_V(swcqe->opcode) |
                                 CQE_TYPE_V(1) |
                                 CQE_SWCQE_V(1) |
                                 CQE_QPID_V(wq->sq.qid));
        CQE_WRID_SQ_IDX(&cqe) = swcqe->idx;
        cqe.bits_type_ts = cpu_to_be64(CQE_GENBIT_V((u64)cq->gen));
        cq->sw_queue[cq->sw_pidx] = cqe;
        t4_swcq_produce(cq);
}

static void advance_oldest_read(struct t4_wq *wq);

int c4iw_flush_sq(struct c4iw_qp *qhp)
{
        int flushed = 0;
        struct t4_wq *wq = &qhp->wq;
        struct c4iw_cq *chp = to_c4iw_cq(qhp->ibqp.send_cq);
        struct t4_cq *cq = &chp->cq;
        int idx;
        struct t4_swsqe *swsqe;

        if (wq->sq.flush_cidx == -1)
                wq->sq.flush_cidx = wq->sq.cidx;
        idx = wq->sq.flush_cidx;
        BUG_ON(idx >= wq->sq.size);
        while (idx != wq->sq.pidx) {
                swsqe = &wq->sq.sw_sq[idx];
                BUG_ON(swsqe->flushed);
                swsqe->flushed = 1;
                insert_sq_cqe(wq, cq, swsqe);
                if (wq->sq.oldest_read == swsqe) {
                        BUG_ON(swsqe->opcode != FW_RI_READ_REQ);
                        advance_oldest_read(wq);
                }
                flushed++;
                if (++idx == wq->sq.size)
                        idx = 0;
        }
        wq->sq.flush_cidx += flushed;
        if (wq->sq.flush_cidx >= wq->sq.size)
                wq->sq.flush_cidx -= wq->sq.size;
        return flushed;
}

static void flush_completed_wrs(struct t4_wq *wq, struct t4_cq *cq)
{
        struct t4_swsqe *swsqe;
        int cidx;

        if (wq->sq.flush_cidx == -1)
                wq->sq.flush_cidx = wq->sq.cidx;
        cidx = wq->sq.flush_cidx;
        BUG_ON(cidx > wq->sq.size);

        while (cidx != wq->sq.pidx) {
                swsqe = &wq->sq.sw_sq[cidx];
                if (!swsqe->signaled) {
                        if (++cidx == wq->sq.size)
                                cidx = 0;
                } else if (swsqe->complete) {

                        BUG_ON(swsqe->flushed);

                        /*
                         * Insert this completed cqe into the swcq.
                         */
                        pr_debug("%s moving cqe into swcq sq idx %u cq idx %u\n",
                                 __func__, cidx, cq->sw_pidx);
                        swsqe->cqe.header |= htonl(CQE_SWCQE_V(1));
                        cq->sw_queue[cq->sw_pidx] = swsqe->cqe;
                        t4_swcq_produce(cq);
                        swsqe->flushed = 1;
                        if (++cidx == wq->sq.size)
                                cidx = 0;
                        wq->sq.flush_cidx = cidx;
                } else
                        break;
        }
}

static void create_read_req_cqe(struct t4_wq *wq, struct t4_cqe *hw_cqe,
                struct t4_cqe *read_cqe)
{
        read_cqe->u.scqe.cidx = wq->sq.oldest_read->idx;
        read_cqe->len = htonl(wq->sq.oldest_read->read_len);
        read_cqe->header = htonl(CQE_QPID_V(CQE_QPID(hw_cqe)) |
                        CQE_SWCQE_V(SW_CQE(hw_cqe)) |
                        CQE_OPCODE_V(FW_RI_READ_REQ) |
                        CQE_TYPE_V(1));
        read_cqe->bits_type_ts = hw_cqe->bits_type_ts;
}

static void advance_oldest_read(struct t4_wq *wq)
{

        u32 rptr = wq->sq.oldest_read - wq->sq.sw_sq + 1;

        if (rptr == wq->sq.size)
                rptr = 0;
        while (rptr != wq->sq.pidx) {
                wq->sq.oldest_read = &wq->sq.sw_sq[rptr];

                if (wq->sq.oldest_read->opcode == FW_RI_READ_REQ)
                        return;
                if (++rptr == wq->sq.size)
                        rptr = 0;
        }
        wq->sq.oldest_read = NULL;
}

/*
 * Move all CQEs from the HWCQ into the SWCQ.
 * Deal with out-of-order and/or completions that complete
 * prior unsignalled WRs.
 */
void c4iw_flush_hw_cq(struct c4iw_cq *chp)
{
        struct t4_cqe *hw_cqe, *swcqe, read_cqe;
        struct c4iw_qp *qhp;
        struct t4_swsqe *swsqe;
        int ret;

        pr_debug("%s  cqid 0x%x\n", __func__, chp->cq.cqid);
        ret = t4_next_hw_cqe(&chp->cq, &hw_cqe);

        /*
         * This logic is similar to poll_cq(), but not quite the same
         * unfortunately.  Need to move pertinent HW CQEs to the SW CQ but
         * also do any translation magic that poll_cq() normally does.
         */
        while (!ret) {
                qhp = get_qhp(chp->rhp, CQE_QPID(hw_cqe));

                /*
                 * drop CQEs with no associated QP
                 */
                if (qhp == NULL)
                        goto next_cqe;

                if (CQE_OPCODE(hw_cqe) == FW_RI_TERMINATE)
                        goto next_cqe;

                if (CQE_OPCODE(hw_cqe) == FW_RI_READ_RESP) {

                        /* If we have reached here because of async
                         * event or other error, and have egress error
                         * then drop
                         */
                        if (CQE_TYPE(hw_cqe) == 1)
                                goto next_cqe;

                        /* drop peer2peer RTR reads.
                         */
                        if (CQE_WRID_STAG(hw_cqe) == 1)
                                goto next_cqe;

                        /*
                         * Eat completions for unsignaled read WRs.
                         */
                        if (!qhp->wq.sq.oldest_read->signaled) {
                                advance_oldest_read(&qhp->wq);
                                goto next_cqe;
                        }

                        /*
                         * Don't write to the HWCQ, create a new read req CQE
                         * in local memory and move it into the swcq.
                         */
                        create_read_req_cqe(&qhp->wq, hw_cqe, &read_cqe);
                        hw_cqe = &read_cqe;
                        advance_oldest_read(&qhp->wq);
                }

                /* if its a SQ completion, then do the magic to move all the
                 * unsignaled and now in-order completions into the swcq.
                 */
                if (SQ_TYPE(hw_cqe)) {
                        swsqe = &qhp->wq.sq.sw_sq[CQE_WRID_SQ_IDX(hw_cqe)];
                        swsqe->cqe = *hw_cqe;
                        swsqe->complete = 1;
                        flush_completed_wrs(&qhp->wq, &chp->cq);
                } else {
                        swcqe = &chp->cq.sw_queue[chp->cq.sw_pidx];
                        *swcqe = *hw_cqe;
                        swcqe->header |= cpu_to_be32(CQE_SWCQE_V(1));
                        t4_swcq_produce(&chp->cq);
                }
next_cqe:
                t4_hwcq_consume(&chp->cq);
                ret = t4_next_hw_cqe(&chp->cq, &hw_cqe);
        }
}

static int cqe_completes_wr(struct t4_cqe *cqe, struct t4_wq *wq)
{
        if (CQE_OPCODE(cqe) == FW_RI_TERMINATE)
                return 0;

        if ((CQE_OPCODE(cqe) == FW_RI_RDMA_WRITE) && RQ_TYPE(cqe))
                return 0;

        if ((CQE_OPCODE(cqe) == FW_RI_READ_RESP) && SQ_TYPE(cqe))
                return 0;

        if (CQE_SEND_OPCODE(cqe) && RQ_TYPE(cqe) && t4_rq_empty(wq))
                return 0;
        return 1;
}

void c4iw_count_rcqes(struct t4_cq *cq, struct t4_wq *wq, int *count)
{
        struct t4_cqe *cqe;
        u32 ptr;

        *count = 0;
        pr_debug("%s count zero %d\n", __func__, *count);
        ptr = cq->sw_cidx;
        while (ptr != cq->sw_pidx) {
                cqe = &cq->sw_queue[ptr];
                if (RQ_TYPE(cqe) && (CQE_OPCODE(cqe) != FW_RI_READ_RESP) &&
                    (CQE_QPID(cqe) == wq->sq.qid) && cqe_completes_wr(cqe, wq))
                        (*count)++;
                if (++ptr == cq->size)
                        ptr = 0;
        }
        pr_debug("%s cq %p count %d\n", __func__, cq, *count);
}

/*
 * poll_cq
 *
 * Caller must:
 *     check the validity of the first CQE,
 *     supply the wq assicated with the qpid.
 *
 * credit: cq credit to return to sge.
 * cqe_flushed: 1 iff the CQE is flushed.
 * cqe: copy of the polled CQE.
 *
 * return value:
 *    0             CQE returned ok.
 *    -EAGAIN       CQE skipped, try again.
 *    -EOVERFLOW    CQ overflow detected.
 */
static int poll_cq(struct t4_wq *wq, struct t4_cq *cq, struct t4_cqe *cqe,
                   u8 *cqe_flushed, u64 *cookie, u32 *credit)
{
        int ret = 0;
        struct t4_cqe *hw_cqe, read_cqe;

        *cqe_flushed = 0;
        *credit = 0;
        ret = t4_next_cqe(cq, &hw_cqe);
        if (ret)
                return ret;

        pr_debug("%s CQE OVF %u qpid 0x%0x genbit %u type %u status 0x%0x opcode 0x%0x len 0x%0x wrid_hi_stag 0x%x wrid_low_msn 0x%x\n",
                 __func__, CQE_OVFBIT(hw_cqe), CQE_QPID(hw_cqe),
                 CQE_GENBIT(hw_cqe), CQE_TYPE(hw_cqe), CQE_STATUS(hw_cqe),
                 CQE_OPCODE(hw_cqe), CQE_LEN(hw_cqe), CQE_WRID_HI(hw_cqe),
                 CQE_WRID_LOW(hw_cqe));

        /*
         * skip cqe's not affiliated with a QP.
         */
        if (wq == NULL) {
                ret = -EAGAIN;
                goto skip_cqe;
        }

        /*
        * skip hw cqe's if the wq is flushed.
        */
        if (wq->flushed && !SW_CQE(hw_cqe)) {
                ret = -EAGAIN;
                goto skip_cqe;
        }

        /*
         * skip TERMINATE cqes...
         */
        if (CQE_OPCODE(hw_cqe) == FW_RI_TERMINATE) {
                ret = -EAGAIN;
                goto skip_cqe;
        }

        /*
         * Special cqe for drain WR completions...
         */
        if (CQE_OPCODE(hw_cqe) == C4IW_DRAIN_OPCODE) {
                *cookie = CQE_DRAIN_COOKIE(hw_cqe);
                *cqe = *hw_cqe;
                goto skip_cqe;
        }

        /*
         * Gotta tweak READ completions:
         *      1) the cqe doesn't contain the sq_wptr from the wr.
         *      2) opcode not reflected from the wr.
         *      3) read_len not reflected from the wr.
         *      4) cq_type is RQ_TYPE not SQ_TYPE.
         */
        if (RQ_TYPE(hw_cqe) && (CQE_OPCODE(hw_cqe) == FW_RI_READ_RESP)) {

                /* If we have reached here because of async
                 * event or other error, and have egress error
                 * then drop
                 */
                if (CQE_TYPE(hw_cqe) == 1) {
                        if (CQE_STATUS(hw_cqe))
                                t4_set_wq_in_error(wq);
                        ret = -EAGAIN;
                        goto skip_cqe;
                }

                /* If this is an unsolicited read response, then the read
                 * was generated by the kernel driver as part of peer-2-peer
                 * connection setup.  So ignore the completion.
                 */
                if (CQE_WRID_STAG(hw_cqe) == 1) {
                        if (CQE_STATUS(hw_cqe))
                                t4_set_wq_in_error(wq);
                        ret = -EAGAIN;
                        goto skip_cqe;
                }

                /*
                 * Eat completions for unsignaled read WRs.
                 */
                if (!wq->sq.oldest_read->signaled) {
                        advance_oldest_read(wq);
                        ret = -EAGAIN;
                        goto skip_cqe;
                }

                /*
                 * Don't write to the HWCQ, so create a new read req CQE
                 * in local memory.
                 */
                create_read_req_cqe(wq, hw_cqe, &read_cqe);
                hw_cqe = &read_cqe;
                advance_oldest_read(wq);
        }

        if (CQE_STATUS(hw_cqe) || t4_wq_in_error(wq)) {
                *cqe_flushed = (CQE_STATUS(hw_cqe) == T4_ERR_SWFLUSH);
                t4_set_wq_in_error(wq);
        }

        /*
         * RECV completion.
         */
        if (RQ_TYPE(hw_cqe)) {

                /*
                 * HW only validates 4 bits of MSN.  So we must validate that
                 * the MSN in the SEND is the next expected MSN.  If its not,
                 * then we complete this with T4_ERR_MSN and mark the wq in
                 * error.
                 */

                if (t4_rq_empty(wq)) {
                        t4_set_wq_in_error(wq);
                        ret = -EAGAIN;
                        goto skip_cqe;
                }
                if (unlikely((CQE_WRID_MSN(hw_cqe) != (wq->rq.msn)))) {
                        t4_set_wq_in_error(wq);
                        hw_cqe->header |= htonl(CQE_STATUS_V(T4_ERR_MSN));
                        goto proc_cqe;
                }
                goto proc_cqe;
        }

        /*
         * If we get here its a send completion.
         *
         * Handle out of order completion. These get stuffed
         * in the SW SQ. Then the SW SQ is walked to move any
         * now in-order completions into the SW CQ.  This handles
         * 2 cases:
         *      1) reaping unsignaled WRs when the first subsequent
         *         signaled WR is completed.
         *      2) out of order read completions.
         */
        if (!SW_CQE(hw_cqe) && (CQE_WRID_SQ_IDX(hw_cqe) != wq->sq.cidx)) {
                struct t4_swsqe *swsqe;

                pr_debug("%s out of order completion going in sw_sq at idx %u\n",
                         __func__, CQE_WRID_SQ_IDX(hw_cqe));
                swsqe = &wq->sq.sw_sq[CQE_WRID_SQ_IDX(hw_cqe)];
                swsqe->cqe = *hw_cqe;
                swsqe->complete = 1;
                ret = -EAGAIN;
                goto flush_wq;
        }

proc_cqe:
        *cqe = *hw_cqe;

        /*
         * Reap the associated WR(s) that are freed up with this
         * completion.
         */
        if (SQ_TYPE(hw_cqe)) {
                int idx = CQE_WRID_SQ_IDX(hw_cqe);
                BUG_ON(idx >= wq->sq.size);

                /*
                * Account for any unsignaled completions completed by
                * this signaled completion.  In this case, cidx points
                * to the first unsignaled one, and idx points to the
                * signaled one.  So adjust in_use based on this delta.
                * if this is not completing any unsigned wrs, then the
                * delta will be 0. Handle wrapping also!
                */
                if (idx < wq->sq.cidx)
                        wq->sq.in_use -= wq->sq.size + idx - wq->sq.cidx;
                else
                        wq->sq.in_use -= idx - wq->sq.cidx;
                BUG_ON(wq->sq.in_use <= 0 && wq->sq.in_use >= wq->sq.size);

                wq->sq.cidx = (uint16_t)idx;
                pr_debug("%s completing sq idx %u\n", __func__, wq->sq.cidx);
                *cookie = wq->sq.sw_sq[wq->sq.cidx].wr_id;
                if (c4iw_wr_log)
                        c4iw_log_wr_stats(wq, hw_cqe);
                t4_sq_consume(wq);
        } else {
                pr_debug("%s completing rq idx %u\n", __func__, wq->rq.cidx);
                *cookie = wq->rq.sw_rq[wq->rq.cidx].wr_id;
                BUG_ON(t4_rq_empty(wq));
                if (c4iw_wr_log)
                        c4iw_log_wr_stats(wq, hw_cqe);
                t4_rq_consume(wq);
                goto skip_cqe;
        }

flush_wq:
        /*
         * Flush any completed cqes that are now in-order.
         */
        flush_completed_wrs(wq, cq);

skip_cqe:
        if (SW_CQE(hw_cqe)) {
                pr_debug("%s cq %p cqid 0x%x skip sw cqe cidx %u\n",
                         __func__, cq, cq->cqid, cq->sw_cidx);
                t4_swcq_consume(cq);
        } else {
                pr_debug("%s cq %p cqid 0x%x skip hw cqe cidx %u\n",
                         __func__, cq, cq->cqid, cq->cidx);
                t4_hwcq_consume(cq);
        }
        return ret;
}

/*
 * Get one cq entry from c4iw and map it to openib.
 *
 * Returns:
 *      0                       cqe returned
 *      -ENODATA                EMPTY;
 *      -EAGAIN                 caller must try again
 *      any other -errno        fatal error
 */
static int c4iw_poll_cq_one(struct c4iw_cq *chp, struct ib_wc *wc)
{
        struct c4iw_qp *qhp = NULL;
        struct t4_cqe uninitialized_var(cqe), *rd_cqe;
        struct t4_wq *wq;
        u32 credit = 0;
        u8 cqe_flushed;
        u64 cookie = 0;
        int ret;

        ret = t4_next_cqe(&chp->cq, &rd_cqe);

        if (ret)
                return ret;

        qhp = get_qhp(chp->rhp, CQE_QPID(rd_cqe));
        if (!qhp)
                wq = NULL;
        else {
                spin_lock(&qhp->lock);
                wq = &(qhp->wq);
        }
        ret = poll_cq(wq, &(chp->cq), &cqe, &cqe_flushed, &cookie, &credit);
        if (ret)
                goto out;

        wc->wr_id = cookie;
        wc->qp = &qhp->ibqp;
        wc->vendor_err = CQE_STATUS(&cqe);
        wc->wc_flags = 0;

        pr_debug("%s qpid 0x%x type %d opcode %d status 0x%x len %u wrid hi 0x%x lo 0x%x cookie 0x%llx\n",
                 __func__, CQE_QPID(&cqe),
                 CQE_TYPE(&cqe), CQE_OPCODE(&cqe),
                 CQE_STATUS(&cqe), CQE_LEN(&cqe),
                 CQE_WRID_HI(&cqe), CQE_WRID_LOW(&cqe),
                 (unsigned long long)cookie);

        if (CQE_TYPE(&cqe) == 0) {
                if (!CQE_STATUS(&cqe))
                        wc->byte_len = CQE_LEN(&cqe);
                else
                        wc->byte_len = 0;
                wc->opcode = IB_WC_RECV;
                if (CQE_OPCODE(&cqe) == FW_RI_SEND_WITH_INV ||
                    CQE_OPCODE(&cqe) == FW_RI_SEND_WITH_SE_INV) {
                        wc->ex.invalidate_rkey = CQE_WRID_STAG(&cqe);
                        wc->wc_flags |= IB_WC_WITH_INVALIDATE;
                        c4iw_invalidate_mr(qhp->rhp, wc->ex.invalidate_rkey);
                }
        } else {
                switch (CQE_OPCODE(&cqe)) {
                case FW_RI_RDMA_WRITE:
                        wc->opcode = IB_WC_RDMA_WRITE;
                        break;
                case FW_RI_READ_REQ:
                        wc->opcode = IB_WC_RDMA_READ;
                        wc->byte_len = CQE_LEN(&cqe);
                        break;
                case FW_RI_SEND_WITH_INV:
                case FW_RI_SEND_WITH_SE_INV:
                        wc->opcode = IB_WC_SEND;
                        wc->wc_flags |= IB_WC_WITH_INVALIDATE;
                        break;
                case FW_RI_SEND:
                case FW_RI_SEND_WITH_SE:
                        wc->opcode = IB_WC_SEND;
                        break;

                case FW_RI_LOCAL_INV:
                        wc->opcode = IB_WC_LOCAL_INV;
                        break;
                case FW_RI_FAST_REGISTER:
                        wc->opcode = IB_WC_REG_MR;

                        /* Invalidate the MR if the fastreg failed */
                        if (CQE_STATUS(&cqe) != T4_ERR_SUCCESS)
                                c4iw_invalidate_mr(qhp->rhp,
                                                   CQE_WRID_FR_STAG(&cqe));
                        break;
                case C4IW_DRAIN_OPCODE:
                        wc->opcode = IB_WC_SEND;
                        break;
                default:
                        pr_err("Unexpected opcode %d in the CQE received for QPID=0x%0x\n",
                               CQE_OPCODE(&cqe), CQE_QPID(&cqe));
                        ret = -EINVAL;
                        goto out;
                }
        }

        if (cqe_flushed)
                wc->status = IB_WC_WR_FLUSH_ERR;
        else {

                switch (CQE_STATUS(&cqe)) {
                case T4_ERR_SUCCESS:
                        wc->status = IB_WC_SUCCESS;
                        break;
                case T4_ERR_STAG:
                        wc->status = IB_WC_LOC_ACCESS_ERR;
                        break;
                case T4_ERR_PDID:
                        wc->status = IB_WC_LOC_PROT_ERR;
                        break;
                case T4_ERR_QPID:
                case T4_ERR_ACCESS:
                        wc->status = IB_WC_LOC_ACCESS_ERR;
                        break;
                case T4_ERR_WRAP:
                        wc->status = IB_WC_GENERAL_ERR;
                        break;
                case T4_ERR_BOUND:
                        wc->status = IB_WC_LOC_LEN_ERR;
                        break;
                case T4_ERR_INVALIDATE_SHARED_MR:
                case T4_ERR_INVALIDATE_MR_WITH_MW_BOUND:
                        wc->status = IB_WC_MW_BIND_ERR;
                        break;
                case T4_ERR_CRC:
                case T4_ERR_MARKER:
                case T4_ERR_PDU_LEN_ERR:
                case T4_ERR_OUT_OF_RQE:
                case T4_ERR_DDP_VERSION:
                case T4_ERR_RDMA_VERSION:
                case T4_ERR_DDP_QUEUE_NUM:
                case T4_ERR_MSN:
                case T4_ERR_TBIT:
                case T4_ERR_MO:
                case T4_ERR_MSN_RANGE:
                case T4_ERR_IRD_OVERFLOW:
                case T4_ERR_OPCODE:
                case T4_ERR_INTERNAL_ERR:
                        wc->status = IB_WC_FATAL_ERR;
                        break;
                case T4_ERR_SWFLUSH:
                        wc->status = IB_WC_WR_FLUSH_ERR;
                        break;
                default:
                        pr_err("Unexpected cqe_status 0x%x for QPID=0x%0x\n",
                               CQE_STATUS(&cqe), CQE_QPID(&cqe));
                        wc->status = IB_WC_FATAL_ERR;
                }
        }
out:
        if (wq)
                spin_unlock(&qhp->lock);
        return ret;
}

int c4iw_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *wc)
{
        struct c4iw_cq *chp;
        unsigned long flags;
        int npolled;
        int err = 0;

        chp = to_c4iw_cq(ibcq);

        spin_lock_irqsave(&chp->lock, flags);
        for (npolled = 0; npolled < num_entries; ++npolled) {
                do {
                        err = c4iw_poll_cq_one(chp, wc + npolled);
                } while (err == -EAGAIN);
                if (err)
                        break;
        }
        spin_unlock_irqrestore(&chp->lock, flags);
        return !err || err == -ENODATA ? npolled : err;
}

int c4iw_destroy_cq(struct ib_cq *ib_cq)
{
        struct c4iw_cq *chp;
        struct c4iw_ucontext *ucontext;

        pr_debug("%s ib_cq %p\n", __func__, ib_cq);
        chp = to_c4iw_cq(ib_cq);

        remove_handle(chp->rhp, &chp->rhp->cqidr, chp->cq.cqid);
        atomic_dec(&chp->refcnt);
        wait_event(chp->wait, !atomic_read(&chp->refcnt));

        ucontext = ib_cq->uobject ? to_c4iw_ucontext(ib_cq->uobject->context)
                                  : NULL;
        destroy_cq(&chp->rhp->rdev, &chp->cq,
                   ucontext ? &ucontext->uctx : &chp->cq.rdev->uctx,
                   chp->destroy_skb);
        chp->destroy_skb = NULL;
        kfree(chp);
        return 0;
}

struct ib_cq *c4iw_create_cq(struct ib_device *ibdev,
                             const struct ib_cq_init_attr *attr,
                             struct ib_ucontext *ib_context,
                             struct ib_udata *udata)
{
        int entries = attr->cqe;
        int vector = attr->comp_vector;
        struct c4iw_dev *rhp;
        struct c4iw_cq *chp;
        struct c4iw_create_cq_resp uresp;
        struct c4iw_ucontext *ucontext = NULL;
        int ret, wr_len;
        size_t memsize, hwentries;
        struct c4iw_mm_entry *mm, *mm2;

        pr_debug("%s ib_dev %p entries %d\n", __func__, ibdev, entries);
        if (attr->flags)
                return ERR_PTR(-EINVAL);

        rhp = to_c4iw_dev(ibdev);

        if (vector >= rhp->rdev.lldi.nciq)
                return ERR_PTR(-EINVAL);

        chp = kzalloc(sizeof(*chp), GFP_KERNEL);
        if (!chp)
                return ERR_PTR(-ENOMEM);

        wr_len = sizeof(struct fw_ri_res_wr) + sizeof(struct fw_ri_res);
        chp->destroy_skb = alloc_skb(wr_len, GFP_KERNEL);
        if (!chp->destroy_skb) {
                ret = -ENOMEM;
                goto err1;
        }

        if (ib_context)
                ucontext = to_c4iw_ucontext(ib_context);

        /* account for the status page. */
        entries++;

        /* IQ needs one extra entry to differentiate full vs empty. */
        entries++;

        /*
         * entries must be multiple of 16 for HW.
         */
        entries = roundup(entries, 16);

        /*
         * Make actual HW queue 2x to avoid cdix_inc overflows.
         */
        hwentries = min(entries * 2, rhp->rdev.hw_queue.t4_max_iq_size);

        /*
         * Make HW queue at least 64 entries so GTS updates aren't too
         * frequent.
         */
        if (hwentries < 64)
                hwentries = 64;

        memsize = hwentries * sizeof *chp->cq.queue;

        /*
         * memsize must be a multiple of the page size if its a user cq.
         */
        if (ucontext)
                memsize = roundup(memsize, PAGE_SIZE);
        chp->cq.size = hwentries;
        chp->cq.memsize = memsize;
        chp->cq.vector = vector;

        ret = create_cq(&rhp->rdev, &chp->cq,
                        ucontext ? &ucontext->uctx : &rhp->rdev.uctx);
        if (ret)
                goto err2;

        chp->rhp = rhp;
        chp->cq.size--;                         /* status page */
        chp->ibcq.cqe = entries - 2;
        spin_lock_init(&chp->lock);
        spin_lock_init(&chp->comp_handler_lock);
        atomic_set(&chp->refcnt, 1);
        init_waitqueue_head(&chp->wait);
        ret = insert_handle(rhp, &rhp->cqidr, chp, chp->cq.cqid);
        if (ret)
                goto err3;

        if (ucontext) {
                mm = kmalloc(sizeof *mm, GFP_KERNEL);
                if (!mm)
                        goto err4;
                mm2 = kmalloc(sizeof *mm2, GFP_KERNEL);
                if (!mm2)
                        goto err5;

                uresp.qid_mask = rhp->rdev.cqmask;
                uresp.cqid = chp->cq.cqid;
                uresp.size = chp->cq.size;
                uresp.memsize = chp->cq.memsize;
                spin_lock(&ucontext->mmap_lock);
                uresp.key = ucontext->key;
                ucontext->key += PAGE_SIZE;
                uresp.gts_key = ucontext->key;
                ucontext->key += PAGE_SIZE;
                spin_unlock(&ucontext->mmap_lock);
                ret = ib_copy_to_udata(udata, &uresp,
                                       sizeof(uresp) - sizeof(uresp.reserved));
                if (ret)
                        goto err6;

                mm->key = uresp.key;
                mm->addr = virt_to_phys(chp->cq.queue);
                mm->len = chp->cq.memsize;
                insert_mmap(ucontext, mm);

                mm2->key = uresp.gts_key;
                mm2->addr = chp->cq.bar2_pa;
                mm2->len = PAGE_SIZE;
                insert_mmap(ucontext, mm2);
        }
        pr_debug("%s cqid 0x%0x chp %p size %u memsize %zu, dma_addr 0x%0llx\n",
                 __func__, chp->cq.cqid, chp, chp->cq.size,
                 chp->cq.memsize, (unsigned long long)chp->cq.dma_addr);
        return &chp->ibcq;
err6:
        kfree(mm2);
err5:
        kfree(mm);
err4:
        remove_handle(rhp, &rhp->cqidr, chp->cq.cqid);
err3:
        destroy_cq(&chp->rhp->rdev, &chp->cq,
                   ucontext ? &ucontext->uctx : &rhp->rdev.uctx,
                   chp->destroy_skb);
err2:
        kfree_skb(chp->destroy_skb);
err1:
        kfree(chp);
        return ERR_PTR(ret);
}

int c4iw_resize_cq(struct ib_cq *cq, int cqe, struct ib_udata *udata)
{
        return -ENOSYS;
}

int c4iw_arm_cq(struct ib_cq *ibcq, enum ib_cq_notify_flags flags)
{
        struct c4iw_cq *chp;
        int ret = 0;
        unsigned long flag;

        chp = to_c4iw_cq(ibcq);
        spin_lock_irqsave(&chp->lock, flag);
        t4_arm_cq(&chp->cq,
                  (flags & IB_CQ_SOLICITED_MASK) == IB_CQ_SOLICITED);
        if (flags & IB_CQ_REPORT_MISSED_EVENTS)
                ret = t4_cq_notempty(&chp->cq);
        spin_unlock_irqrestore(&chp->lock, flag);
        return ret;
}