// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
/*
 * Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
 * Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
 */

#include <linux/skbuff.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, 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);
                }
        }
}

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;
        struct rxe_queue *q = qp->sq.queue;
        unsigned int cons;
        unsigned int prod;

        cons = queue_get_consumer(q, QUEUE_TYPE_FROM_CLIENT);
        prod = queue_get_producer(q, QUEUE_TYPE_FROM_CLIENT);

        qp->req.wqe_index       = cons;
        qp->req.psn             = qp->comp.psn;
        qp->req.opcode          = -1;

        for (wqe_index = cons; wqe_index != prod;
                        wqe_index = queue_next_index(q, wqe_index)) {
                wqe = queue_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, 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 = timer_container_of(qp, t, rnr_nak_timer);
        unsigned long flags;

        rxe_dbg_qp(qp, "nak timer fired\n");

        if (!rxe_get(qp))
                return;
        spin_lock_irqsave(&qp->state_lock, flags);
        if (qp->valid) {
                /* request a send queue retry */
                qp->req.need_retry = 1;
                qp->req.wait_for_rnr_timer = 0;
                rxe_sched_task(&qp->send_task);
        }
        spin_unlock_irqrestore(&qp->state_lock, flags);
        rxe_put(qp);
}

static void req_check_sq_drain_done(struct rxe_qp *qp)
{
        struct rxe_queue *q;
        unsigned int index;
        unsigned int cons;
        struct rxe_send_wqe *wqe;
        unsigned long flags;

        spin_lock_irqsave(&qp->state_lock, flags);
        if (qp_state(qp) == IB_QPS_SQD) {
                q = qp->sq.queue;
                index = qp->req.wqe_index;
                cons = queue_get_consumer(q, QUEUE_TYPE_FROM_CLIENT);
                wqe = queue_addr_from_index(q, cons);

                /* check to see if we are drained;
                 * state_lock used by requester and completer
                 */
                do {
                        if (!qp->attr.sq_draining)
                                /* comp just finished */
                                break;

                        if (wqe && ((index != cons) ||
                                (wqe->state != wqe_state_posted)))
                                /* comp not done yet */
                                break;

                        qp->attr.sq_draining = 0;
                        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);
                        }
                        return;
                } while (0);
        }
        spin_unlock_irqrestore(&qp->state_lock, flags);
}

static struct rxe_send_wqe *__req_next_wqe(struct rxe_qp *qp)
{
        struct rxe_queue *q = qp->sq.queue;
        unsigned int index = qp->req.wqe_index;
        unsigned int prod;

        prod = queue_get_producer(q, QUEUE_TYPE_FROM_CLIENT);
        if (index == prod)
                return NULL;
        else
                return queue_addr_from_index(q, index);
}

static struct rxe_send_wqe *req_next_wqe(struct rxe_qp *qp)
{
        struct rxe_send_wqe *wqe;
        unsigned long flags;

        req_check_sq_drain_done(qp);

        wqe = __req_next_wqe(qp);
        if (wqe == NULL)
                return NULL;

        spin_lock_irqsave(&qp->state_lock, flags);
        if (unlikely((qp_state(qp) == IB_QPS_SQD) &&
                     (wqe->state != wqe_state_processing))) {
                spin_unlock_irqrestore(&qp->state_lock, flags);
                return NULL;
        }
        spin_unlock_irqrestore(&qp->state_lock, flags);

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

/**
 * rxe_wqe_is_fenced - check if next wqe is fenced
 * @qp: the queue pair
 * @wqe: the next wqe
 *
 * Returns: 1 if wqe needs to wait
 *          0 if wqe is ready to go
 */
static int rxe_wqe_is_fenced(struct rxe_qp *qp, struct rxe_send_wqe *wqe)
{
        /* Local invalidate fence (LIF) see IBA 10.6.5.1
         * Requires ALL previous operations on the send queue
         * are complete. Make mandatory for the rxe driver.
         */
        if (wqe->wr.opcode == IB_WR_LOCAL_INV)
                return qp->req.wqe_index != queue_get_consumer(qp->sq.queue,
                                                QUEUE_TYPE_FROM_CLIENT);

        /* Fence see IBA 10.8.3.3
         * Requires that all previous read and atomic operations
         * are complete.
         */
        return (wqe->wr.send_flags & IB_SEND_FENCE) &&
                atomic_read(&qp->req.rd_atomic) != qp->attr.max_rd_atomic;
}

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_FLUSH:
                return IB_OPCODE_RC_FLUSH;

        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_ATOMIC_WRITE:
                return IB_OPCODE_RC_ATOMIC_WRITE;

        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_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_av *av,
                                       struct rxe_send_wqe *wqe,
                                       int opcode, u32 payload,
                                       struct rxe_pkt_info *pkt)
{
        struct rxe_dev          *rxe = to_rdev(qp->ibqp.device);
        struct sk_buff          *skb;
        struct rxe_send_wr      *ibwr = &wqe->wr;
        int                     pad = (-payload) & 0x3;
        int                     paylen;
        int                     solicited;
        u32                     qp_num;
        int                     ack_req = 0;

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

        /* init skb */
        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));

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

        if (qp_type(qp) != IB_QPT_UD && qp_type(qp) != IB_QPT_UC)
                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, IB_DEFAULT_PKEY_FULL, qp_num,
                 ack_req, pkt->psn);

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

        /* Fill Flush Extension Transport Header */
        if (pkt->mask & RXE_FETH_MASK)
                feth_init(pkt, ibwr->wr.flush.type, ibwr->wr.flush.level);

        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) {
                        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 finish_packet(struct rxe_qp *qp, struct rxe_av *av,
                         struct rxe_send_wqe *wqe, struct rxe_pkt_info *pkt,
                         struct sk_buff *skb, u32 payload)
{
        int err;

        err = rxe_prepare(av, pkt, skb);
        if (err)
                return err;

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

                        memcpy(payload_addr(pkt), tmp, payload);

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

                        memset(pad, 0, bth_pad(pkt));
                }
        } else if (pkt->mask & RXE_FLUSH_MASK) {
                /* oA19-2: shall have no payload. */
                wqe->dma.resid = 0;
        }

        if (pkt->mask & RXE_ATOMIC_WRITE_MASK) {
                memcpy(payload_addr(pkt), wqe->dma.atomic_wr, payload);
                wqe->dma.resid -= payload;
        }

        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_done;
        } 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,
                           u32 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 update_state(struct rxe_qp *qp, struct rxe_pkt_info *pkt)
{
        qp->req.opcode = pkt->opcode;

        if (pkt->mask & RXE_END_MASK)
                qp->req.wqe_index = queue_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);
}

static int rxe_do_local_ops(struct rxe_qp *qp, struct rxe_send_wqe *wqe)
{
        u8 opcode = wqe->wr.opcode;
        u32 rkey;
        int ret;

        switch (opcode) {
        case IB_WR_LOCAL_INV:
                rkey = wqe->wr.ex.invalidate_rkey;
                if (rkey_is_mw(rkey))
                        ret = rxe_invalidate_mw(qp, rkey);
                else
                        ret = rxe_invalidate_mr(qp, rkey);

                if (unlikely(ret)) {
                        wqe->status = IB_WC_LOC_QP_OP_ERR;
                        return ret;
                }
                break;
        case IB_WR_REG_MR:
                ret = rxe_reg_fast_mr(qp, wqe);
                if (unlikely(ret)) {
                        wqe->status = IB_WC_LOC_QP_OP_ERR;
                        return ret;
                }
                break;
        case IB_WR_BIND_MW:
                ret = rxe_bind_mw(qp, wqe);
                if (unlikely(ret)) {
                        wqe->status = IB_WC_MW_BIND_ERR;
                        return ret;
                }
                break;
        default:
                rxe_dbg_qp(qp, "Unexpected send wqe opcode %d\n", opcode);
                wqe->status = IB_WC_LOC_QP_OP_ERR;
                return -EINVAL;
        }

        wqe->state = wqe_state_done;
        wqe->status = IB_WC_SUCCESS;
        qp->req.wqe_index = queue_next_index(qp->sq.queue, qp->req.wqe_index);

        return 0;
}

int rxe_requester(struct rxe_qp *qp)
{
        struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
        struct rxe_pkt_info pkt;
        struct sk_buff *skb;
        struct rxe_send_wqe *wqe;
        enum rxe_hdr_mask mask;
        u32 payload;
        int mtu;
        int opcode;
        int err;
        int ret;
        struct rxe_queue *q = qp->sq.queue;
        struct rxe_ah *ah;
        struct rxe_av *av;
        unsigned long flags;

        spin_lock_irqsave(&qp->state_lock, flags);
        if (unlikely(!qp->valid)) {
                spin_unlock_irqrestore(&qp->state_lock, flags);
                goto exit;
        }

        if (unlikely(qp_state(qp) == IB_QPS_ERR)) {
                wqe = __req_next_wqe(qp);
                spin_unlock_irqrestore(&qp->state_lock, flags);
                if (wqe) {
                        wqe->status = IB_WC_WR_FLUSH_ERR;
                        goto err;
                } else {
                        goto exit;
                }
        }

        if (unlikely(qp_state(qp) == IB_QPS_RESET)) {
                qp->req.wqe_index = queue_get_consumer(q,
                                                QUEUE_TYPE_FROM_CLIENT);
                qp->req.opcode = -1;
                qp->req.need_rd_atomic = 0;
                qp->req.wait_psn = 0;
                qp->req.need_retry = 0;
                qp->req.wait_for_rnr_timer = 0;
                spin_unlock_irqrestore(&qp->state_lock, flags);
                goto exit;
        }
        spin_unlock_irqrestore(&qp->state_lock, flags);

        /* we come here if the retransmit timer has fired
         * or if the rnr timer has fired. If the retransmit
         * timer fires while we are processing an RNR NAK wait
         * until the rnr timer has fired before starting the
         * retry flow
         */
        if (unlikely(qp->req.need_retry && !qp->req.wait_for_rnr_timer)) {
                req_retry(qp);
                qp->req.need_retry = 0;
        }

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

        if (rxe_wqe_is_fenced(qp, wqe)) {
                qp->req.wait_fence = 1;
                goto exit;
        }

        if (wqe->mask & WR_LOCAL_OP_MASK) {
                err = rxe_do_local_ops(qp, wqe);
                if (unlikely(err))
                        goto err;
                else
                        goto done;
        }

        if (unlikely(qp_type(qp) == IB_QPT_RC &&
                psn_compare(qp->req.psn, (qp->comp.psn +
                                RXE_MAX_UNACKED_PSNS)) > 0)) {
                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 err;
        }

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

        mtu = get_mtu(qp);
        payload = (mask & (RXE_WRITE_OR_SEND_MASK | RXE_ATOMIC_WRITE_MASK)) ?
                        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 = queue_next_index(qp->sq.queue,
                                                       qp->req.wqe_index);
                        wqe->state = wqe_state_done;
                        wqe->status = IB_WC_SUCCESS;
                        goto done;
                }
                payload = mtu;
        }

        pkt.rxe = rxe;
        pkt.opcode = opcode;
        pkt.qp = qp;
        pkt.psn = qp->req.psn;
        pkt.mask = rxe_opcode[opcode].mask;
        pkt.wqe = wqe;

        av = rxe_get_av(&pkt, &ah);
        if (unlikely(!av)) {
                rxe_dbg_qp(qp, "Failed no address vector\n");
                wqe->status = IB_WC_LOC_QP_OP_ERR;
                goto err;
        }

        skb = init_req_packet(qp, av, wqe, opcode, payload, &pkt);
        if (unlikely(!skb)) {
                rxe_dbg_qp(qp, "Failed allocating skb\n");
                wqe->status = IB_WC_LOC_QP_OP_ERR;
                if (ah)
                        rxe_put(ah);
                goto err;
        }

        err = finish_packet(qp, av, wqe, &pkt, skb, payload);
        if (unlikely(err)) {
                rxe_dbg_qp(qp, "Error during finish packet\n");
                if (err == -EFAULT)
                        wqe->status = IB_WC_LOC_PROT_ERR;
                else
                        wqe->status = IB_WC_LOC_QP_OP_ERR;
                kfree_skb(skb);
                if (ah)
                        rxe_put(ah);
                goto err;
        }

        if (ah)
                rxe_put(ah);

        err = rxe_xmit_packet(qp, &pkt, skb);
        if (err) {
                wqe->status = IB_WC_LOC_QP_OP_ERR;
                goto err;
        }

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

        /* A non-zero return value will cause rxe_do_task to
         * exit its loop and end the work item. A zero return
         * will continue looping and return to rxe_requester
         */
done:
        ret = 0;
        goto out;
err:
        /* update wqe_index for each wqe completion */
        qp->req.wqe_index = queue_next_index(qp->sq.queue, qp->req.wqe_index);
        wqe->state = wqe_state_error;
        rxe_qp_error(qp);
exit:
        ret = -EAGAIN;
out:
        return ret;
}

int rxe_sender(struct rxe_qp *qp)
{
        int req_ret;
        int comp_ret;

        /* process the send queue */
        req_ret = rxe_requester(qp);

        /* process the response queue */
        comp_ret = rxe_completer(qp);

        /* exit the task loop if both requester and completer
         * are ready
         */
        return (req_ret && comp_ret) ? -EAGAIN : 0;
}