Linux 4.19.133

[linux/fpc-iii.git] / drivers / infiniband / sw / rxe / rxe_req.c

/*
 * Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
 * Copyright (c) 2015 System Fabric Works, 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/skbuff.h>
#include <crypto/hash.h>

#include "rxe.h"
#include "rxe_loc.h"
#include "rxe_queue.h"

static int next_opcode(struct rxe_qp *qp, struct rxe_send_wqe *wqe,
                       u32 opcode);

static inline void retry_first_write_send(struct rxe_qp *qp,
                                          struct rxe_send_wqe *wqe,
                                          unsigned int mask, int npsn)
{
        int i;

        for (i = 0; i < npsn; i++) {
                int to_send = (wqe->dma.resid > qp->mtu) ?
                                qp->mtu : wqe->dma.resid;

                qp->req.opcode = next_opcode(qp, wqe,
                                             wqe->wr.opcode);

                if (wqe->wr.send_flags & IB_SEND_INLINE) {
                        wqe->dma.resid -= to_send;
                        wqe->dma.sge_offset += to_send;
                } else {
                        advance_dma_data(&wqe->dma, to_send);
                }
                if (mask & WR_WRITE_MASK)
                        wqe->iova += qp->mtu;
        }
}

static void req_retry(struct rxe_qp *qp)
{
        struct rxe_send_wqe *wqe;
        unsigned int wqe_index;
        unsigned int mask;
        int npsn;
        int first = 1;

        qp->req.wqe_index       = consumer_index(qp->sq.queue);
        qp->req.psn             = qp->comp.psn;
        qp->req.opcode          = -1;

        for (wqe_index = consumer_index(qp->sq.queue);
                wqe_index != producer_index(qp->sq.queue);
                wqe_index = next_index(qp->sq.queue, wqe_index)) {
                wqe = addr_from_index(qp->sq.queue, wqe_index);
                mask = wr_opcode_mask(wqe->wr.opcode, qp);

                if (wqe->state == wqe_state_posted)
                        break;

                if (wqe->state == wqe_state_done)
                        continue;

                wqe->iova = (mask & WR_ATOMIC_MASK) ?
                             wqe->wr.wr.atomic.remote_addr :
                             (mask & WR_READ_OR_WRITE_MASK) ?
                             wqe->wr.wr.rdma.remote_addr :
                             0;

                if (!first || (mask & WR_READ_MASK) == 0) {
                        wqe->dma.resid = wqe->dma.length;
                        wqe->dma.cur_sge = 0;
                        wqe->dma.sge_offset = 0;
                }

                if (first) {
                        first = 0;

                        if (mask & WR_WRITE_OR_SEND_MASK) {
                                npsn = (qp->comp.psn - wqe->first_psn) &
                                        BTH_PSN_MASK;
                                retry_first_write_send(qp, wqe, mask, npsn);
                        }

                        if (mask & WR_READ_MASK) {
                                npsn = (wqe->dma.length - wqe->dma.resid) /
                                        qp->mtu;
                                wqe->iova += npsn * qp->mtu;
                        }
                }

                wqe->state = wqe_state_posted;
        }
}

void rnr_nak_timer(struct timer_list *t)
{
        struct rxe_qp *qp = from_timer(qp, t, rnr_nak_timer);

        pr_debug("qp#%d rnr nak timer fired\n", qp_num(qp));
        rxe_run_task(&qp->req.task, 1);
}

static struct rxe_send_wqe *req_next_wqe(struct rxe_qp *qp)
{
        struct rxe_send_wqe *wqe = queue_head(qp->sq.queue);
        unsigned long flags;

        if (unlikely(qp->req.state == QP_STATE_DRAIN)) {
                /* check to see if we are drained;
                 * state_lock used by requester and completer
                 */
                spin_lock_irqsave(&qp->state_lock, flags);
                do {
                        if (qp->req.state != QP_STATE_DRAIN) {
                                /* comp just finished */
                                spin_unlock_irqrestore(&qp->state_lock,
                                                       flags);
                                break;
                        }

                        if (wqe && ((qp->req.wqe_index !=
                                consumer_index(qp->sq.queue)) ||
                                (wqe->state != wqe_state_posted))) {
                                /* comp not done yet */
                                spin_unlock_irqrestore(&qp->state_lock,
                                                       flags);
                                break;
                        }

                        qp->req.state = QP_STATE_DRAINED;
                        spin_unlock_irqrestore(&qp->state_lock, flags);

                        if (qp->ibqp.event_handler) {
                                struct ib_event ev;

                                ev.device = qp->ibqp.device;
                                ev.element.qp = &qp->ibqp;
                                ev.event = IB_EVENT_SQ_DRAINED;
                                qp->ibqp.event_handler(&ev,
                                        qp->ibqp.qp_context);
                        }
                } while (0);
        }

        if (qp->req.wqe_index == producer_index(qp->sq.queue))
                return NULL;

        wqe = addr_from_index(qp->sq.queue, qp->req.wqe_index);

        if (unlikely((qp->req.state == QP_STATE_DRAIN ||
                      qp->req.state == QP_STATE_DRAINED) &&
                     (wqe->state != wqe_state_processing)))
                return NULL;

        if (unlikely((wqe->wr.send_flags & IB_SEND_FENCE) &&
                     (qp->req.wqe_index != consumer_index(qp->sq.queue)))) {
                qp->req.wait_fence = 1;
                return NULL;
        }

        wqe->mask = wr_opcode_mask(wqe->wr.opcode, qp);
        return wqe;
}

static int next_opcode_rc(struct rxe_qp *qp, u32 opcode, int fits)
{
        switch (opcode) {
        case IB_WR_RDMA_WRITE:
                if (qp->req.opcode == IB_OPCODE_RC_RDMA_WRITE_FIRST ||
                    qp->req.opcode == IB_OPCODE_RC_RDMA_WRITE_MIDDLE)
                        return fits ?
                                IB_OPCODE_RC_RDMA_WRITE_LAST :
                                IB_OPCODE_RC_RDMA_WRITE_MIDDLE;
                else
                        return fits ?
                                IB_OPCODE_RC_RDMA_WRITE_ONLY :
                                IB_OPCODE_RC_RDMA_WRITE_FIRST;

        case IB_WR_RDMA_WRITE_WITH_IMM:
                if (qp->req.opcode == IB_OPCODE_RC_RDMA_WRITE_FIRST ||
                    qp->req.opcode == IB_OPCODE_RC_RDMA_WRITE_MIDDLE)
                        return fits ?
                                IB_OPCODE_RC_RDMA_WRITE_LAST_WITH_IMMEDIATE :
                                IB_OPCODE_RC_RDMA_WRITE_MIDDLE;
                else
                        return fits ?
                                IB_OPCODE_RC_RDMA_WRITE_ONLY_WITH_IMMEDIATE :
                                IB_OPCODE_RC_RDMA_WRITE_FIRST;

        case IB_WR_SEND:
                if (qp->req.opcode == IB_OPCODE_RC_SEND_FIRST ||
                    qp->req.opcode == IB_OPCODE_RC_SEND_MIDDLE)
                        return fits ?
                                IB_OPCODE_RC_SEND_LAST :
                                IB_OPCODE_RC_SEND_MIDDLE;
                else
                        return fits ?
                                IB_OPCODE_RC_SEND_ONLY :
                                IB_OPCODE_RC_SEND_FIRST;

        case IB_WR_SEND_WITH_IMM:
                if (qp->req.opcode == IB_OPCODE_RC_SEND_FIRST ||
                    qp->req.opcode == IB_OPCODE_RC_SEND_MIDDLE)
                        return fits ?
                                IB_OPCODE_RC_SEND_LAST_WITH_IMMEDIATE :
                                IB_OPCODE_RC_SEND_MIDDLE;
                else
                        return fits ?
                                IB_OPCODE_RC_SEND_ONLY_WITH_IMMEDIATE :
                                IB_OPCODE_RC_SEND_FIRST;

        case IB_WR_RDMA_READ:
                return IB_OPCODE_RC_RDMA_READ_REQUEST;

        case IB_WR_ATOMIC_CMP_AND_SWP:
                return IB_OPCODE_RC_COMPARE_SWAP;

        case IB_WR_ATOMIC_FETCH_AND_ADD:
                return IB_OPCODE_RC_FETCH_ADD;

        case IB_WR_SEND_WITH_INV:
                if (qp->req.opcode == IB_OPCODE_RC_SEND_FIRST ||
                    qp->req.opcode == IB_OPCODE_RC_SEND_MIDDLE)
                        return fits ? IB_OPCODE_RC_SEND_LAST_WITH_INVALIDATE :
                                IB_OPCODE_RC_SEND_MIDDLE;
                else
                        return fits ? IB_OPCODE_RC_SEND_ONLY_WITH_INVALIDATE :
                                IB_OPCODE_RC_SEND_FIRST;
        case IB_WR_REG_MR:
        case IB_WR_LOCAL_INV:
                return opcode;
        }

        return -EINVAL;
}

static int next_opcode_uc(struct rxe_qp *qp, u32 opcode, int fits)
{
        switch (opcode) {
        case IB_WR_RDMA_WRITE:
                if (qp->req.opcode == IB_OPCODE_UC_RDMA_WRITE_FIRST ||
                    qp->req.opcode == IB_OPCODE_UC_RDMA_WRITE_MIDDLE)
                        return fits ?
                                IB_OPCODE_UC_RDMA_WRITE_LAST :
                                IB_OPCODE_UC_RDMA_WRITE_MIDDLE;
                else
                        return fits ?
                                IB_OPCODE_UC_RDMA_WRITE_ONLY :
                                IB_OPCODE_UC_RDMA_WRITE_FIRST;

        case IB_WR_RDMA_WRITE_WITH_IMM:
                if (qp->req.opcode == IB_OPCODE_UC_RDMA_WRITE_FIRST ||
                    qp->req.opcode == IB_OPCODE_UC_RDMA_WRITE_MIDDLE)
                        return fits ?
                                IB_OPCODE_UC_RDMA_WRITE_LAST_WITH_IMMEDIATE :
                                IB_OPCODE_UC_RDMA_WRITE_MIDDLE;
                else
                        return fits ?
                                IB_OPCODE_UC_RDMA_WRITE_ONLY_WITH_IMMEDIATE :
                                IB_OPCODE_UC_RDMA_WRITE_FIRST;

        case IB_WR_SEND:
                if (qp->req.opcode == IB_OPCODE_UC_SEND_FIRST ||
                    qp->req.opcode == IB_OPCODE_UC_SEND_MIDDLE)
                        return fits ?
                                IB_OPCODE_UC_SEND_LAST :
                                IB_OPCODE_UC_SEND_MIDDLE;
                else
                        return fits ?
                                IB_OPCODE_UC_SEND_ONLY :
                                IB_OPCODE_UC_SEND_FIRST;

        case IB_WR_SEND_WITH_IMM:
                if (qp->req.opcode == IB_OPCODE_UC_SEND_FIRST ||
                    qp->req.opcode == IB_OPCODE_UC_SEND_MIDDLE)
                        return fits ?
                                IB_OPCODE_UC_SEND_LAST_WITH_IMMEDIATE :
                                IB_OPCODE_UC_SEND_MIDDLE;
                else
                        return fits ?
                                IB_OPCODE_UC_SEND_ONLY_WITH_IMMEDIATE :
                                IB_OPCODE_UC_SEND_FIRST;
        }

        return -EINVAL;
}

static int next_opcode(struct rxe_qp *qp, struct rxe_send_wqe *wqe,
                       u32 opcode)
{
        int fits = (wqe->dma.resid <= qp->mtu);

        switch (qp_type(qp)) {
        case IB_QPT_RC:
                return next_opcode_rc(qp, opcode, fits);

        case IB_QPT_UC:
                return next_opcode_uc(qp, opcode, fits);

        case IB_QPT_SMI:
        case IB_QPT_UD:
        case IB_QPT_GSI:
                switch (opcode) {
                case IB_WR_SEND:
                        return IB_OPCODE_UD_SEND_ONLY;

                case IB_WR_SEND_WITH_IMM:
                        return IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE;
                }
                break;

        default:
                break;
        }

        return -EINVAL;
}

static inline int check_init_depth(struct rxe_qp *qp, struct rxe_send_wqe *wqe)
{
        int depth;

        if (wqe->has_rd_atomic)
                return 0;

        qp->req.need_rd_atomic = 1;
        depth = atomic_dec_return(&qp->req.rd_atomic);

        if (depth >= 0) {
                qp->req.need_rd_atomic = 0;
                wqe->has_rd_atomic = 1;
                return 0;
        }

        atomic_inc(&qp->req.rd_atomic);
        return -EAGAIN;
}

static inline int get_mtu(struct rxe_qp *qp)
{
        struct rxe_dev *rxe = to_rdev(qp->ibqp.device);

        if ((qp_type(qp) == IB_QPT_RC) || (qp_type(qp) == IB_QPT_UC))
                return qp->mtu;

        return rxe->port.mtu_cap;
}

static struct sk_buff *init_req_packet(struct rxe_qp *qp,
                                       struct rxe_send_wqe *wqe,
                                       int opcode, int payload,
                                       struct rxe_pkt_info *pkt)
{
        struct rxe_dev          *rxe = to_rdev(qp->ibqp.device);
        struct rxe_port         *port = &rxe->port;
        struct sk_buff          *skb;
        struct rxe_send_wr      *ibwr = &wqe->wr;
        struct rxe_av           *av;
        int                     pad = (-payload) & 0x3;
        int                     paylen;
        int                     solicited;
        u16                     pkey;
        u32                     qp_num;
        int                     ack_req;

        /* length from start of bth to end of icrc */
        paylen = rxe_opcode[opcode].length + payload + pad + RXE_ICRC_SIZE;

        /* pkt->hdr, rxe, port_num and mask are initialized in ifc
         * layer
         */
        pkt->opcode     = opcode;
        pkt->qp         = qp;
        pkt->psn        = qp->req.psn;
        pkt->mask       = rxe_opcode[opcode].mask;
        pkt->paylen     = paylen;
        pkt->offset     = 0;
        pkt->wqe        = wqe;

        /* init skb */
        av = rxe_get_av(pkt);
        skb = rxe_init_packet(rxe, av, paylen, pkt);
        if (unlikely(!skb))
                return NULL;

        /* init bth */
        solicited = (ibwr->send_flags & IB_SEND_SOLICITED) &&
                        (pkt->mask & RXE_END_MASK) &&
                        ((pkt->mask & (RXE_SEND_MASK)) ||
                        (pkt->mask & (RXE_WRITE_MASK | RXE_IMMDT_MASK)) ==
                        (RXE_WRITE_MASK | RXE_IMMDT_MASK));

        pkey = (qp_type(qp) == IB_QPT_GSI) ?
                 port->pkey_tbl[ibwr->wr.ud.pkey_index] :
                 port->pkey_tbl[qp->attr.pkey_index];

        qp_num = (pkt->mask & RXE_DETH_MASK) ? ibwr->wr.ud.remote_qpn :
                                         qp->attr.dest_qp_num;

        ack_req = ((pkt->mask & RXE_END_MASK) ||
                (qp->req.noack_pkts++ > RXE_MAX_PKT_PER_ACK));
        if (ack_req)
                qp->req.noack_pkts = 0;

        bth_init(pkt, pkt->opcode, solicited, 0, pad, pkey, qp_num,
                 ack_req, pkt->psn);

        /* init optional headers */
        if (pkt->mask & RXE_RETH_MASK) {
                reth_set_rkey(pkt, ibwr->wr.rdma.rkey);
                reth_set_va(pkt, wqe->iova);
                reth_set_len(pkt, wqe->dma.resid);
        }

        if (pkt->mask & RXE_IMMDT_MASK)
                immdt_set_imm(pkt, ibwr->ex.imm_data);

        if (pkt->mask & RXE_IETH_MASK)
                ieth_set_rkey(pkt, ibwr->ex.invalidate_rkey);

        if (pkt->mask & RXE_ATMETH_MASK) {
                atmeth_set_va(pkt, wqe->iova);
                if (opcode == IB_OPCODE_RC_COMPARE_SWAP ||
                    opcode == IB_OPCODE_RD_COMPARE_SWAP) {
                        atmeth_set_swap_add(pkt, ibwr->wr.atomic.swap);
                        atmeth_set_comp(pkt, ibwr->wr.atomic.compare_add);
                } else {
                        atmeth_set_swap_add(pkt, ibwr->wr.atomic.compare_add);
                }
                atmeth_set_rkey(pkt, ibwr->wr.atomic.rkey);
        }

        if (pkt->mask & RXE_DETH_MASK) {
                if (qp->ibqp.qp_num == 1)
                        deth_set_qkey(pkt, GSI_QKEY);
                else
                        deth_set_qkey(pkt, ibwr->wr.ud.remote_qkey);
                deth_set_sqp(pkt, qp->ibqp.qp_num);
        }

        return skb;
}

static int fill_packet(struct rxe_qp *qp, struct rxe_send_wqe *wqe,
                       struct rxe_pkt_info *pkt, struct sk_buff *skb,
                       int paylen)
{
        struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
        u32 crc = 0;
        u32 *p;
        int err;

        err = rxe_prepare(rxe, pkt, skb, &crc);
        if (err)
                return err;

        if (pkt->mask & RXE_WRITE_OR_SEND) {
                if (wqe->wr.send_flags & IB_SEND_INLINE) {
                        u8 *tmp = &wqe->dma.inline_data[wqe->dma.sge_offset];

                        crc = rxe_crc32(rxe, crc, tmp, paylen);
                        memcpy(payload_addr(pkt), tmp, paylen);

                        wqe->dma.resid -= paylen;
                        wqe->dma.sge_offset += paylen;
                } else {
                        err = copy_data(qp->pd, 0, &wqe->dma,
                                        payload_addr(pkt), paylen,
                                        from_mem_obj,
                                        &crc);
                        if (err)
                                return err;
                }
                if (bth_pad(pkt)) {
                        u8 *pad = payload_addr(pkt) + paylen;

                        memset(pad, 0, bth_pad(pkt));
                        crc = rxe_crc32(rxe, crc, pad, bth_pad(pkt));
                }
        }
        p = payload_addr(pkt) + paylen + bth_pad(pkt);

        *p = ~crc;

        return 0;
}

static void update_wqe_state(struct rxe_qp *qp,
                struct rxe_send_wqe *wqe,
                struct rxe_pkt_info *pkt)
{
        if (pkt->mask & RXE_END_MASK) {
                if (qp_type(qp) == IB_QPT_RC)
                        wqe->state = wqe_state_pending;
        } else {
                wqe->state = wqe_state_processing;
        }
}

static void update_wqe_psn(struct rxe_qp *qp,
                           struct rxe_send_wqe *wqe,
                           struct rxe_pkt_info *pkt,
                           int payload)
{
        /* number of packets left to send including current one */
        int num_pkt = (wqe->dma.resid + payload + qp->mtu - 1) / qp->mtu;

        /* handle zero length packet case */
        if (num_pkt == 0)
                num_pkt = 1;

        if (pkt->mask & RXE_START_MASK) {
                wqe->first_psn = qp->req.psn;
                wqe->last_psn = (qp->req.psn + num_pkt - 1) & BTH_PSN_MASK;
        }

        if (pkt->mask & RXE_READ_MASK)
                qp->req.psn = (wqe->first_psn + num_pkt) & BTH_PSN_MASK;
        else
                qp->req.psn = (qp->req.psn + 1) & BTH_PSN_MASK;
}

static void save_state(struct rxe_send_wqe *wqe,
                       struct rxe_qp *qp,
                       struct rxe_send_wqe *rollback_wqe,
                       u32 *rollback_psn)
{
        rollback_wqe->state     = wqe->state;
        rollback_wqe->first_psn = wqe->first_psn;
        rollback_wqe->last_psn  = wqe->last_psn;
        *rollback_psn           = qp->req.psn;
}

static void rollback_state(struct rxe_send_wqe *wqe,
                           struct rxe_qp *qp,
                           struct rxe_send_wqe *rollback_wqe,
                           u32 rollback_psn)
{
        wqe->state     = rollback_wqe->state;
        wqe->first_psn = rollback_wqe->first_psn;
        wqe->last_psn  = rollback_wqe->last_psn;
        qp->req.psn    = rollback_psn;
}

static void update_state(struct rxe_qp *qp, struct rxe_send_wqe *wqe,
                         struct rxe_pkt_info *pkt, int payload)
{
        qp->req.opcode = pkt->opcode;

        if (pkt->mask & RXE_END_MASK)
                qp->req.wqe_index = next_index(qp->sq.queue, qp->req.wqe_index);

        qp->need_req_skb = 0;

        if (qp->qp_timeout_jiffies && !timer_pending(&qp->retrans_timer))
                mod_timer(&qp->retrans_timer,
                          jiffies + qp->qp_timeout_jiffies);
}

int rxe_requester(void *arg)
{
        struct rxe_qp *qp = (struct rxe_qp *)arg;
        struct rxe_pkt_info pkt;
        struct sk_buff *skb;
        struct rxe_send_wqe *wqe;
        enum rxe_hdr_mask mask;
        int payload;
        int mtu;
        int opcode;
        int ret;
        struct rxe_send_wqe rollback_wqe;
        u32 rollback_psn;

        rxe_add_ref(qp);

next_wqe:
        if (unlikely(!qp->valid || qp->req.state == QP_STATE_ERROR))
                goto exit;

        if (unlikely(qp->req.state == QP_STATE_RESET)) {
                qp->req.wqe_index = consumer_index(qp->sq.queue);
                qp->req.opcode = -1;
                qp->req.need_rd_atomic = 0;
                qp->req.wait_psn = 0;
                qp->req.need_retry = 0;
                goto exit;
        }

        if (unlikely(qp->req.need_retry)) {
                req_retry(qp);
                qp->req.need_retry = 0;
        }

        wqe = req_next_wqe(qp);
        if (unlikely(!wqe))
                goto exit;

        if (wqe->mask & WR_REG_MASK) {
                if (wqe->wr.opcode == IB_WR_LOCAL_INV) {
                        struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
                        struct rxe_mem *rmr;

                        rmr = rxe_pool_get_index(&rxe->mr_pool,
                                                 wqe->wr.ex.invalidate_rkey >> 8);
                        if (!rmr) {
                                pr_err("No mr for key %#x\n",
                                       wqe->wr.ex.invalidate_rkey);
                                wqe->state = wqe_state_error;
                                wqe->status = IB_WC_MW_BIND_ERR;
                                goto exit;
                        }
                        rmr->state = RXE_MEM_STATE_FREE;
                        rxe_drop_ref(rmr);
                        wqe->state = wqe_state_done;
                        wqe->status = IB_WC_SUCCESS;
                } else if (wqe->wr.opcode == IB_WR_REG_MR) {
                        struct rxe_mem *rmr = to_rmr(wqe->wr.wr.reg.mr);

                        rmr->state = RXE_MEM_STATE_VALID;
                        rmr->access = wqe->wr.wr.reg.access;
                        rmr->lkey = wqe->wr.wr.reg.key;
                        rmr->rkey = wqe->wr.wr.reg.key;
                        rmr->iova = wqe->wr.wr.reg.mr->iova;
                        wqe->state = wqe_state_done;
                        wqe->status = IB_WC_SUCCESS;
                } else {
                        goto exit;
                }
                if ((wqe->wr.send_flags & IB_SEND_SIGNALED) ||
                    qp->sq_sig_type == IB_SIGNAL_ALL_WR)
                        rxe_run_task(&qp->comp.task, 1);
                qp->req.wqe_index = next_index(qp->sq.queue,
                                                qp->req.wqe_index);
                goto next_wqe;
        }

        if (unlikely(qp_type(qp) == IB_QPT_RC &&
                     qp->req.psn > (qp->comp.psn + RXE_MAX_UNACKED_PSNS))) {
                qp->req.wait_psn = 1;
                goto exit;
        }

        /* Limit the number of inflight SKBs per QP */
        if (unlikely(atomic_read(&qp->skb_out) >
                     RXE_INFLIGHT_SKBS_PER_QP_HIGH)) {
                qp->need_req_skb = 1;
                goto exit;
        }

        opcode = next_opcode(qp, wqe, wqe->wr.opcode);
        if (unlikely(opcode < 0)) {
                wqe->status = IB_WC_LOC_QP_OP_ERR;
                goto exit;
        }

        mask = rxe_opcode[opcode].mask;
        if (unlikely(mask & RXE_READ_OR_ATOMIC)) {
                if (check_init_depth(qp, wqe))
                        goto exit;
        }

        mtu = get_mtu(qp);
        payload = (mask & RXE_WRITE_OR_SEND) ? wqe->dma.resid : 0;
        if (payload > mtu) {
                if (qp_type(qp) == IB_QPT_UD) {
                        /* C10-93.1.1: If the total sum of all the buffer lengths specified for a
                         * UD message exceeds the MTU of the port as returned by QueryHCA, the CI
                         * shall not emit any packets for this message. Further, the CI shall not
                         * generate an error due to this condition.
                         */

                        /* fake a successful UD send */
                        wqe->first_psn = qp->req.psn;
                        wqe->last_psn = qp->req.psn;
                        qp->req.psn = (qp->req.psn + 1) & BTH_PSN_MASK;
                        qp->req.opcode = IB_OPCODE_UD_SEND_ONLY;
                        qp->req.wqe_index = next_index(qp->sq.queue,
                                                       qp->req.wqe_index);
                        wqe->state = wqe_state_done;
                        wqe->status = IB_WC_SUCCESS;
                        __rxe_do_task(&qp->comp.task);
                        rxe_drop_ref(qp);
                        return 0;
                }
                payload = mtu;
        }

        skb = init_req_packet(qp, wqe, opcode, payload, &pkt);
        if (unlikely(!skb)) {
                pr_err("qp#%d Failed allocating skb\n", qp_num(qp));
                goto err;
        }

        if (fill_packet(qp, wqe, &pkt, skb, payload)) {
                pr_debug("qp#%d Error during fill packet\n", qp_num(qp));
                kfree_skb(skb);
                goto err;
        }

        /*
         * To prevent a race on wqe access between requester and completer,
         * wqe members state and psn need to be set before calling
         * rxe_xmit_packet().
         * Otherwise, completer might initiate an unjustified retry flow.
         */
        save_state(wqe, qp, &rollback_wqe, &rollback_psn);
        update_wqe_state(qp, wqe, &pkt);
        update_wqe_psn(qp, wqe, &pkt, payload);
        ret = rxe_xmit_packet(to_rdev(qp->ibqp.device), qp, &pkt, skb);
        if (ret) {
                qp->need_req_skb = 1;

                rollback_state(wqe, qp, &rollback_wqe, rollback_psn);

                if (ret == -EAGAIN) {
                        rxe_run_task(&qp->req.task, 1);
                        goto exit;
                }

                goto err;
        }

        update_state(qp, wqe, &pkt, payload);

        goto next_wqe;

err:
        wqe->status = IB_WC_LOC_PROT_ERR;
        wqe->state = wqe_state_error;
        __rxe_do_task(&qp->comp.task);

exit:
        rxe_drop_ref(qp);
        return -EAGAIN;
}