OSCL-LXR linux-6.0.1/​drivers/​infiniband/​hw/​hfi1/​rc.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0 or BSD-3-Clause
 /*
  * Copyright(c) 2015 - 2018 Intel Corporation.
  */
 
 #include <linux/io.h>
 #include <rdma/rdma_vt.h>
 #include <rdma/rdmavt_qp.h>
 
 #include "hfi.h"
 #include "qp.h"
 #include "rc.h"
 #include "verbs_txreq.h"
 #include "trace.h"
 
 struct rvt_ack_entry *find_prev_entry(struct rvt_qp *qp, u32 psn, u8 *prev,
                       u8 *prev_ack, bool *scheduled)
     __must_hold(&qp->s_lock)
 {
     struct rvt_ack_entry *e = NULL;
     u8 i, p;
     bool s = true;
 
     for (i = qp->r_head_ack_queue; ; i = p) {
         if (i == qp->s_tail_ack_queue)
             s = false;
         if (i)
             p = i - 1;
         else
             p = rvt_size_atomic(ib_to_rvt(qp->ibqp.device));
         if (p == qp->r_head_ack_queue) {
             e = NULL;
             break;
         }
         e = &qp->s_ack_queue[p];
         if (!e->opcode) {
             e = NULL;
             break;
         }
         if (cmp_psn(psn, e->psn) >= 0) {
             if (p == qp->s_tail_ack_queue &&
                 cmp_psn(psn, e->lpsn) <= 0)
                 s = false;
             break;
         }
     }
     if (prev)
         *prev = p;
     if (prev_ack)
         *prev_ack = i;
     if (scheduled)
         *scheduled = s;
     return e;
 }
 
 /**
  * make_rc_ack - construct a response packet (ACK, NAK, or RDMA read)
  * @dev: the device for this QP
  * @qp: a pointer to the QP
  * @ohdr: a pointer to the IB header being constructed
  * @ps: the xmit packet state
  *
  * Return 1 if constructed; otherwise, return 0.
  * Note that we are in the responder's side of the QP context.
  * Note the QP s_lock must be held.
  */
 static int make_rc_ack(struct hfi1_ibdev *dev, struct rvt_qp *qp,
                struct ib_other_headers *ohdr,
                struct hfi1_pkt_state *ps)
 {
     struct rvt_ack_entry *e;
     u32 hwords, hdrlen;
     u32 len = 0;
     u32 bth0 = 0, bth2 = 0;
     u32 bth1 = qp->remote_qpn | (HFI1_CAP_IS_KSET(OPFN) << IB_BTHE_E_SHIFT);
     int middle = 0;
     u32 pmtu = qp->pmtu;
     struct hfi1_qp_priv *qpriv = qp->priv;
     bool last_pkt;
     u32 delta;
     u8 next = qp->s_tail_ack_queue;
     struct tid_rdma_request *req;
 
     trace_hfi1_rsp_make_rc_ack(qp, 0);
     lockdep_assert_held(&qp->s_lock);
     /* Don't send an ACK if we aren't supposed to. */
     if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK))
         goto bail;
 
     if (qpriv->hdr_type == HFI1_PKT_TYPE_9B)
         /* header size in 32-bit words LRH+BTH = (8+12)/4. */
         hwords = 5;
     else
         /* header size in 32-bit words 16B LRH+BTH = (16+12)/4. */
         hwords = 7;
 
     switch (qp->s_ack_state) {
     case OP(RDMA_READ_RESPONSE_LAST):
     case OP(RDMA_READ_RESPONSE_ONLY):
         e = &qp->s_ack_queue[qp->s_tail_ack_queue];
         release_rdma_sge_mr(e);
         fallthrough;
     case OP(ATOMIC_ACKNOWLEDGE):
         /*
          * We can increment the tail pointer now that the last
          * response has been sent instead of only being
          * constructed.
          */
         if (++next > rvt_size_atomic(&dev->rdi))
             next = 0;
         /*
          * Only advance the s_acked_ack_queue pointer if there
          * have been no TID RDMA requests.
          */
         e = &qp->s_ack_queue[qp->s_tail_ack_queue];
         if (e->opcode != TID_OP(WRITE_REQ) &&
             qp->s_acked_ack_queue == qp->s_tail_ack_queue)
             qp->s_acked_ack_queue = next;
         qp->s_tail_ack_queue = next;
         trace_hfi1_rsp_make_rc_ack(qp, e->psn);
         fallthrough;
     case OP(SEND_ONLY):
     case OP(ACKNOWLEDGE):
         /* Check for no next entry in the queue. */
         if (qp->r_head_ack_queue == qp->s_tail_ack_queue) {
             if (qp->s_flags & RVT_S_ACK_PENDING)
                 goto normal;
             goto bail;
         }
 
         e = &qp->s_ack_queue[qp->s_tail_ack_queue];
         /* Check for tid write fence */
         if ((qpriv->s_flags & HFI1_R_TID_WAIT_INTERLCK) ||
             hfi1_tid_rdma_ack_interlock(qp, e)) {
             iowait_set_flag(&qpriv->s_iowait, IOWAIT_PENDING_IB);
             goto bail;
         }
         if (e->opcode == OP(RDMA_READ_REQUEST)) {
             /*
              * If a RDMA read response is being resent and
              * we haven't seen the duplicate request yet,
              * then stop sending the remaining responses the
              * responder has seen until the requester re-sends it.
              */
             len = e->rdma_sge.sge_length;
             if (len && !e->rdma_sge.mr) {
                 if (qp->s_acked_ack_queue ==
                     qp->s_tail_ack_queue)
                     qp->s_acked_ack_queue =
                         qp->r_head_ack_queue;
                 qp->s_tail_ack_queue = qp->r_head_ack_queue;
                 goto bail;
             }
             /* Copy SGE state in case we need to resend */
             ps->s_txreq->mr = e->rdma_sge.mr;
             if (ps->s_txreq->mr)
                 rvt_get_mr(ps->s_txreq->mr);
             qp->s_ack_rdma_sge.sge = e->rdma_sge;
             qp->s_ack_rdma_sge.num_sge = 1;
             ps->s_txreq->ss = &qp->s_ack_rdma_sge;
             if (len > pmtu) {
                 len = pmtu;
                 qp->s_ack_state = OP(RDMA_READ_RESPONSE_FIRST);
             } else {
                 qp->s_ack_state = OP(RDMA_READ_RESPONSE_ONLY);
                 e->sent = 1;
             }
             ohdr->u.aeth = rvt_compute_aeth(qp);
             hwords++;
             qp->s_ack_rdma_psn = e->psn;
             bth2 = mask_psn(qp->s_ack_rdma_psn++);
         } else if (e->opcode == TID_OP(WRITE_REQ)) {
             /*
              * If a TID RDMA WRITE RESP is being resent, we have to
              * wait for the actual request. All requests that are to
              * be resent will have their state set to
              * TID_REQUEST_RESEND. When the new request arrives, the
              * state will be changed to TID_REQUEST_RESEND_ACTIVE.
              */
             req = ack_to_tid_req(e);
             if (req->state == TID_REQUEST_RESEND ||
                 req->state == TID_REQUEST_INIT_RESEND)
                 goto bail;
             qp->s_ack_state = TID_OP(WRITE_RESP);
             qp->s_ack_rdma_psn = mask_psn(e->psn + req->cur_seg);
             goto write_resp;
         } else if (e->opcode == TID_OP(READ_REQ)) {
             /*
              * If a TID RDMA read response is being resent and
              * we haven't seen the duplicate request yet,
              * then stop sending the remaining responses the
              * responder has seen until the requester re-sends it.
              */
             len = e->rdma_sge.sge_length;
             if (len && !e->rdma_sge.mr) {
                 if (qp->s_acked_ack_queue ==
                     qp->s_tail_ack_queue)
                     qp->s_acked_ack_queue =
                         qp->r_head_ack_queue;
                 qp->s_tail_ack_queue = qp->r_head_ack_queue;
                 goto bail;
             }
             /* Copy SGE state in case we need to resend */
             ps->s_txreq->mr = e->rdma_sge.mr;
             if (ps->s_txreq->mr)
                 rvt_get_mr(ps->s_txreq->mr);
             qp->s_ack_rdma_sge.sge = e->rdma_sge;
             qp->s_ack_rdma_sge.num_sge = 1;
             qp->s_ack_state = TID_OP(READ_RESP);
             goto read_resp;
         } else {
             /* COMPARE_SWAP or FETCH_ADD */
             ps->s_txreq->ss = NULL;
             len = 0;
             qp->s_ack_state = OP(ATOMIC_ACKNOWLEDGE);
             ohdr->u.at.aeth = rvt_compute_aeth(qp);
             ib_u64_put(e->atomic_data, &ohdr->u.at.atomic_ack_eth);
             hwords += sizeof(ohdr->u.at) / sizeof(u32);
             bth2 = mask_psn(e->psn);
             e->sent = 1;
         }
         trace_hfi1_tid_write_rsp_make_rc_ack(qp);
         bth0 = qp->s_ack_state << 24;
         break;
 
     case OP(RDMA_READ_RESPONSE_FIRST):
         qp->s_ack_state = OP(RDMA_READ_RESPONSE_MIDDLE);
         fallthrough;
     case OP(RDMA_READ_RESPONSE_MIDDLE):
         ps->s_txreq->ss = &qp->s_ack_rdma_sge;
         ps->s_txreq->mr = qp->s_ack_rdma_sge.sge.mr;
         if (ps->s_txreq->mr)
             rvt_get_mr(ps->s_txreq->mr);
         len = qp->s_ack_rdma_sge.sge.sge_length;
         if (len > pmtu) {
             len = pmtu;
             middle = HFI1_CAP_IS_KSET(SDMA_AHG);
         } else {
             ohdr->u.aeth = rvt_compute_aeth(qp);
             hwords++;
             qp->s_ack_state = OP(RDMA_READ_RESPONSE_LAST);
             e = &qp->s_ack_queue[qp->s_tail_ack_queue];
             e->sent = 1;
         }
         bth0 = qp->s_ack_state << 24;
         bth2 = mask_psn(qp->s_ack_rdma_psn++);
         break;
 
     case TID_OP(WRITE_RESP):
 write_resp:
         /*
          * 1. Check if RVT_S_ACK_PENDING is set. If yes,
          *    goto normal.
          * 2. Attempt to allocate TID resources.
          * 3. Remove RVT_S_RESP_PENDING flags from s_flags
          * 4. If resources not available:
          *    4.1 Set RVT_S_WAIT_TID_SPACE
          *    4.2 Queue QP on RCD TID queue
          *    4.3 Put QP on iowait list.
          *    4.4 Build IB RNR NAK with appropriate timeout value
          *    4.5 Return indication progress made.
          * 5. If resources are available:
          *    5.1 Program HW flow CSRs
          *    5.2 Build TID RDMA WRITE RESP packet
          *    5.3 If more resources needed, do 2.1 - 2.3.
          *    5.4 Wake up next QP on RCD TID queue.
          *    5.5 Return indication progress made.
          */
 
         e = &qp->s_ack_queue[qp->s_tail_ack_queue];
         req = ack_to_tid_req(e);
 
         /*
          * Send scheduled RNR NAK's. RNR NAK's need to be sent at
          * segment boundaries, not at request boundaries. Don't change
          * s_ack_state because we are still in the middle of a request
          */
         if (qpriv->rnr_nak_state == TID_RNR_NAK_SEND &&
             qp->s_tail_ack_queue == qpriv->r_tid_alloc &&
             req->cur_seg == req->alloc_seg) {
             qpriv->rnr_nak_state = TID_RNR_NAK_SENT;
             goto normal_no_state;
         }
 
         bth2 = mask_psn(qp->s_ack_rdma_psn);
         hdrlen = hfi1_build_tid_rdma_write_resp(qp, e, ohdr, &bth1,
                             bth2, &len,
                             &ps->s_txreq->ss);
         if (!hdrlen)
             return 0;
 
         hwords += hdrlen;
         bth0 = qp->s_ack_state << 24;
         qp->s_ack_rdma_psn++;
         trace_hfi1_tid_req_make_rc_ack_write(qp, 0, e->opcode, e->psn,
                              e->lpsn, req);
         if (req->cur_seg != req->total_segs)
             break;
 
         e->sent = 1;
         /* Do not free e->rdma_sge until all data are received */
         qp->s_ack_state = OP(ATOMIC_ACKNOWLEDGE);
         break;
 
     case TID_OP(READ_RESP):
 read_resp:
         e = &qp->s_ack_queue[qp->s_tail_ack_queue];
         ps->s_txreq->ss = &qp->s_ack_rdma_sge;
         delta = hfi1_build_tid_rdma_read_resp(qp, e, ohdr, &bth0,
                               &bth1, &bth2, &len,
                               &last_pkt);
         if (delta == 0)
             goto error_qp;
         hwords += delta;
         if (last_pkt) {
             e->sent = 1;
             /*
              * Increment qp->s_tail_ack_queue through s_ack_state
              * transition.
              */
             qp->s_ack_state = OP(RDMA_READ_RESPONSE_LAST);
         }
         break;
     case TID_OP(READ_REQ):
         goto bail;
 
     default:
 normal:
         /*
          * Send a regular ACK.
          * Set the s_ack_state so we wait until after sending
          * the ACK before setting s_ack_state to ACKNOWLEDGE
          * (see above).
          */
         qp->s_ack_state = OP(SEND_ONLY);
 normal_no_state:
         if (qp->s_nak_state)
             ohdr->u.aeth =
                 cpu_to_be32((qp->r_msn & IB_MSN_MASK) |
                         (qp->s_nak_state <<
                          IB_AETH_CREDIT_SHIFT));
         else
             ohdr->u.aeth = rvt_compute_aeth(qp);
         hwords++;
         len = 0;
         bth0 = OP(ACKNOWLEDGE) << 24;
         bth2 = mask_psn(qp->s_ack_psn);
         qp->s_flags &= ~RVT_S_ACK_PENDING;
         ps->s_txreq->txreq.flags |= SDMA_TXREQ_F_VIP;
         ps->s_txreq->ss = NULL;
     }
     qp->s_rdma_ack_cnt++;
     ps->s_txreq->sde = qpriv->s_sde;
     ps->s_txreq->s_cur_size = len;
     ps->s_txreq->hdr_dwords = hwords;
     hfi1_make_ruc_header(qp, ohdr, bth0, bth1, bth2, middle, ps);
     return 1;
 error_qp:
     spin_unlock_irqrestore(&qp->s_lock, ps->flags);
     spin_lock_irqsave(&qp->r_lock, ps->flags);
     spin_lock(&qp->s_lock);
     rvt_error_qp(qp, IB_WC_WR_FLUSH_ERR);
     spin_unlock(&qp->s_lock);
     spin_unlock_irqrestore(&qp->r_lock, ps->flags);
     spin_lock_irqsave(&qp->s_lock, ps->flags);
 bail:
     qp->s_ack_state = OP(ACKNOWLEDGE);
     /*
      * Ensure s_rdma_ack_cnt changes are committed prior to resetting
      * RVT_S_RESP_PENDING
      */
     smp_wmb();
     qp->s_flags &= ~(RVT_S_RESP_PENDING
                 | RVT_S_ACK_PENDING
                 | HFI1_S_AHG_VALID);
     return 0;
 }
 
 /**
  * hfi1_make_rc_req - construct a request packet (SEND, RDMA r/w, ATOMIC)
  * @qp: a pointer to the QP
  * @ps: the current packet state
  *
  * Assumes s_lock is held.
  *
  * Return 1 if constructed; otherwise, return 0.
  */
 int hfi1_make_rc_req(struct rvt_qp *qp, struct hfi1_pkt_state *ps)
 {
     struct hfi1_qp_priv *priv = qp->priv;
     struct hfi1_ibdev *dev = to_idev(qp->ibqp.device);
     struct ib_other_headers *ohdr;
     struct rvt_sge_state *ss = NULL;
     struct rvt_swqe *wqe;
     struct hfi1_swqe_priv *wpriv;
     struct tid_rdma_request *req = NULL;
     /* header size in 32-bit words LRH+BTH = (8+12)/4. */
     u32 hwords = 5;
     u32 len = 0;
     u32 bth0 = 0, bth2 = 0;
     u32 bth1 = qp->remote_qpn | (HFI1_CAP_IS_KSET(OPFN) << IB_BTHE_E_SHIFT);
     u32 pmtu = qp->pmtu;
     char newreq;
     int middle = 0;
     int delta;
     struct tid_rdma_flow *flow = NULL;
     struct tid_rdma_params *remote;
 
     trace_hfi1_sender_make_rc_req(qp);
     lockdep_assert_held(&qp->s_lock);
     ps->s_txreq = get_txreq(ps->dev, qp);
     if (!ps->s_txreq)
         goto bail_no_tx;
 
     if (priv->hdr_type == HFI1_PKT_TYPE_9B) {
         /* header size in 32-bit words LRH+BTH = (8+12)/4. */
         hwords = 5;
         if (rdma_ah_get_ah_flags(&qp->remote_ah_attr) & IB_AH_GRH)
             ohdr = &ps->s_txreq->phdr.hdr.ibh.u.l.oth;
         else
             ohdr = &ps->s_txreq->phdr.hdr.ibh.u.oth;
     } else {
         /* header size in 32-bit words 16B LRH+BTH = (16+12)/4. */
         hwords = 7;
         if ((rdma_ah_get_ah_flags(&qp->remote_ah_attr) & IB_AH_GRH) &&
             (hfi1_check_mcast(rdma_ah_get_dlid(&qp->remote_ah_attr))))
             ohdr = &ps->s_txreq->phdr.hdr.opah.u.l.oth;
         else
             ohdr = &ps->s_txreq->phdr.hdr.opah.u.oth;
     }
 
     /* Sending responses has higher priority over sending requests. */
     if ((qp->s_flags & RVT_S_RESP_PENDING) &&
         make_rc_ack(dev, qp, ohdr, ps))
         return 1;
 
     if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_SEND_OK)) {
         if (!(ib_rvt_state_ops[qp->state] & RVT_FLUSH_SEND))
             goto bail;
         /* We are in the error state, flush the work request. */
         if (qp->s_last == READ_ONCE(qp->s_head))
             goto bail;
         /* If DMAs are in progress, we can't flush immediately. */
         if (iowait_sdma_pending(&priv->s_iowait)) {
             qp->s_flags |= RVT_S_WAIT_DMA;
             goto bail;
         }
         clear_ahg(qp);
         wqe = rvt_get_swqe_ptr(qp, qp->s_last);
         hfi1_trdma_send_complete(qp, wqe, qp->s_last != qp->s_acked ?
                      IB_WC_SUCCESS : IB_WC_WR_FLUSH_ERR);
         /* will get called again */
         goto done_free_tx;
     }
 
     if (qp->s_flags & (RVT_S_WAIT_RNR | RVT_S_WAIT_ACK | HFI1_S_WAIT_HALT))
         goto bail;
 
     if (cmp_psn(qp->s_psn, qp->s_sending_hpsn) <= 0) {
         if (cmp_psn(qp->s_sending_psn, qp->s_sending_hpsn) <= 0) {
             qp->s_flags |= RVT_S_WAIT_PSN;
             goto bail;
         }
         qp->s_sending_psn = qp->s_psn;
         qp->s_sending_hpsn = qp->s_psn - 1;
     }
 
     /* Send a request. */
     wqe = rvt_get_swqe_ptr(qp, qp->s_cur);
 check_s_state:
     switch (qp->s_state) {
     default:
         if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_NEXT_SEND_OK))
             goto bail;
         /*
          * Resend an old request or start a new one.
          *
          * We keep track of the current SWQE so that
          * we don't reset the "furthest progress" state
          * if we need to back up.
          */
         newreq = 0;
         if (qp->s_cur == qp->s_tail) {
             /* Check if send work queue is empty. */
             if (qp->s_tail == READ_ONCE(qp->s_head)) {
                 clear_ahg(qp);
                 goto bail;
             }
             /*
              * If a fence is requested, wait for previous
              * RDMA read and atomic operations to finish.
              * However, there is no need to guard against
              * TID RDMA READ after TID RDMA READ.
              */
             if ((wqe->wr.send_flags & IB_SEND_FENCE) &&
                 qp->s_num_rd_atomic &&
                 (wqe->wr.opcode != IB_WR_TID_RDMA_READ ||
                  priv->pending_tid_r_segs < qp->s_num_rd_atomic)) {
                 qp->s_flags |= RVT_S_WAIT_FENCE;
                 goto bail;
             }
             /*
              * Local operations are processed immediately
              * after all prior requests have completed
              */
             if (wqe->wr.opcode == IB_WR_REG_MR ||
                 wqe->wr.opcode == IB_WR_LOCAL_INV) {
                 int local_ops = 0;
                 int err = 0;
 
                 if (qp->s_last != qp->s_cur)
                     goto bail;
                 if (++qp->s_cur == qp->s_size)
                     qp->s_cur = 0;
                 if (++qp->s_tail == qp->s_size)
                     qp->s_tail = 0;
                 if (!(wqe->wr.send_flags &
                       RVT_SEND_COMPLETION_ONLY)) {
                     err = rvt_invalidate_rkey(
                         qp,
                         wqe->wr.ex.invalidate_rkey);
                     local_ops = 1;
                 }
                 rvt_send_complete(qp, wqe,
                           err ? IB_WC_LOC_PROT_ERR
                               : IB_WC_SUCCESS);
                 if (local_ops)
                     atomic_dec(&qp->local_ops_pending);
                 goto done_free_tx;
             }
 
             newreq = 1;
             qp->s_psn = wqe->psn;
         }
         /*
          * Note that we have to be careful not to modify the
          * original work request since we may need to resend
          * it.
          */
         len = wqe->length;
         ss = &qp->s_sge;
         bth2 = mask_psn(qp->s_psn);
 
         /*
          * Interlock between various IB requests and TID RDMA
          * if necessary.
          */
         if ((priv->s_flags & HFI1_S_TID_WAIT_INTERLCK) ||
             hfi1_tid_rdma_wqe_interlock(qp, wqe))
             goto bail;
 
         switch (wqe->wr.opcode) {
         case IB_WR_SEND:
         case IB_WR_SEND_WITH_IMM:
         case IB_WR_SEND_WITH_INV:
             /* If no credit, return. */
             if (!rvt_rc_credit_avail(qp, wqe))
                 goto bail;
             if (len > pmtu) {
                 qp->s_state = OP(SEND_FIRST);
                 len = pmtu;
                 break;
             }
             if (wqe->wr.opcode == IB_WR_SEND) {
                 qp->s_state = OP(SEND_ONLY);
             } else if (wqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
                 qp->s_state = OP(SEND_ONLY_WITH_IMMEDIATE);
                 /* Immediate data comes after the BTH */
                 ohdr->u.imm_data = wqe->wr.ex.imm_data;
                 hwords += 1;
             } else {
                 qp->s_state = OP(SEND_ONLY_WITH_INVALIDATE);
                 /* Invalidate rkey comes after the BTH */
                 ohdr->u.ieth = cpu_to_be32(
                         wqe->wr.ex.invalidate_rkey);
                 hwords += 1;
             }
             if (wqe->wr.send_flags & IB_SEND_SOLICITED)
                 bth0 |= IB_BTH_SOLICITED;
             bth2 |= IB_BTH_REQ_ACK;
             if (++qp->s_cur == qp->s_size)
                 qp->s_cur = 0;
             break;
 
         case IB_WR_RDMA_WRITE:
             if (newreq && !(qp->s_flags & RVT_S_UNLIMITED_CREDIT))
                 qp->s_lsn++;
             goto no_flow_control;
         case IB_WR_RDMA_WRITE_WITH_IMM:
             /* If no credit, return. */
             if (!rvt_rc_credit_avail(qp, wqe))
                 goto bail;
 no_flow_control:
             put_ib_reth_vaddr(
                 wqe->rdma_wr.remote_addr,
                 &ohdr->u.rc.reth);
             ohdr->u.rc.reth.rkey =
                 cpu_to_be32(wqe->rdma_wr.rkey);
             ohdr->u.rc.reth.length = cpu_to_be32(len);
             hwords += sizeof(struct ib_reth) / sizeof(u32);
             if (len > pmtu) {
                 qp->s_state = OP(RDMA_WRITE_FIRST);
                 len = pmtu;
                 break;
             }
             if (wqe->wr.opcode == IB_WR_RDMA_WRITE) {
                 qp->s_state = OP(RDMA_WRITE_ONLY);
             } else {
                 qp->s_state =
                     OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE);
                 /* Immediate data comes after RETH */
                 ohdr->u.rc.imm_data = wqe->wr.ex.imm_data;
                 hwords += 1;
                 if (wqe->wr.send_flags & IB_SEND_SOLICITED)
                     bth0 |= IB_BTH_SOLICITED;
             }
             bth2 |= IB_BTH_REQ_ACK;
             if (++qp->s_cur == qp->s_size)
                 qp->s_cur = 0;
             break;
 
         case IB_WR_TID_RDMA_WRITE:
             if (newreq) {
                 /*
                  * Limit the number of TID RDMA WRITE requests.
                  */
                 if (atomic_read(&priv->n_tid_requests) >=
                     HFI1_TID_RDMA_WRITE_CNT)
                     goto bail;
 
                 if (!(qp->s_flags & RVT_S_UNLIMITED_CREDIT))
                     qp->s_lsn++;
             }
 
             hwords += hfi1_build_tid_rdma_write_req(qp, wqe, ohdr,
                                 &bth1, &bth2,
                                 &len);
             ss = NULL;
             if (priv->s_tid_cur == HFI1_QP_WQE_INVALID) {
                 priv->s_tid_cur = qp->s_cur;
                 if (priv->s_tid_tail == HFI1_QP_WQE_INVALID) {
                     priv->s_tid_tail = qp->s_cur;
                     priv->s_state = TID_OP(WRITE_RESP);
                 }
             } else if (priv->s_tid_cur == priv->s_tid_head) {
                 struct rvt_swqe *__w;
                 struct tid_rdma_request *__r;
 
                 __w = rvt_get_swqe_ptr(qp, priv->s_tid_cur);
                 __r = wqe_to_tid_req(__w);
 
                 /*
                  * The s_tid_cur pointer is advanced to s_cur if
                  * any of the following conditions about the WQE
                  * to which s_ti_cur currently points to are
                  * satisfied:
                  *   1. The request is not a TID RDMA WRITE
                  *      request,
                  *   2. The request is in the INACTIVE or
                  *      COMPLETE states (TID RDMA READ requests
                  *      stay at INACTIVE and TID RDMA WRITE
                  *      transition to COMPLETE when done),
                  *   3. The request is in the ACTIVE or SYNC
                  *      state and the number of completed
                  *      segments is equal to the total segment
                  *      count.
                  *      (If ACTIVE, the request is waiting for
                  *       ACKs. If SYNC, the request has not
                  *       received any responses because it's
                  *       waiting on a sync point.)
                  */
                 if (__w->wr.opcode != IB_WR_TID_RDMA_WRITE ||
                     __r->state == TID_REQUEST_INACTIVE ||
                     __r->state == TID_REQUEST_COMPLETE ||
                     ((__r->state == TID_REQUEST_ACTIVE ||
                       __r->state == TID_REQUEST_SYNC) &&
                      __r->comp_seg == __r->total_segs)) {
                     if (priv->s_tid_tail ==
                         priv->s_tid_cur &&
                         priv->s_state ==
                         TID_OP(WRITE_DATA_LAST)) {
                         priv->s_tid_tail = qp->s_cur;
                         priv->s_state =
                             TID_OP(WRITE_RESP);
                     }
                     priv->s_tid_cur = qp->s_cur;
                 }
                 /*
                  * A corner case: when the last TID RDMA WRITE
                  * request was completed, s_tid_head,
                  * s_tid_cur, and s_tid_tail all point to the
                  * same location. Other requests are posted and
                  * s_cur wraps around to the same location,
                  * where a new TID RDMA WRITE is posted. In
                  * this case, none of the indices need to be
                  * updated. However, the priv->s_state should.
                  */
                 if (priv->s_tid_tail == qp->s_cur &&
                     priv->s_state == TID_OP(WRITE_DATA_LAST))
                     priv->s_state = TID_OP(WRITE_RESP);
             }
             req = wqe_to_tid_req(wqe);
             if (newreq) {
                 priv->s_tid_head = qp->s_cur;
                 priv->pending_tid_w_resp += req->total_segs;
                 atomic_inc(&priv->n_tid_requests);
                 atomic_dec(&priv->n_requests);
             } else {
                 req->state = TID_REQUEST_RESEND;
                 req->comp_seg = delta_psn(bth2, wqe->psn);
                 /*
                  * Pull back any segments since we are going
                  * to re-receive them.
                  */
                 req->setup_head = req->clear_tail;
                 priv->pending_tid_w_resp +=
                     delta_psn(wqe->lpsn, bth2) + 1;
             }
 
             trace_hfi1_tid_write_sender_make_req(qp, newreq);
             trace_hfi1_tid_req_make_req_write(qp, newreq,
                               wqe->wr.opcode,
                               wqe->psn, wqe->lpsn,
                               req);
             if (++qp->s_cur == qp->s_size)
                 qp->s_cur = 0;
             break;
 
         case IB_WR_RDMA_READ:
             /*
              * Don't allow more operations to be started
              * than the QP limits allow.
              */
             if (qp->s_num_rd_atomic >=
                 qp->s_max_rd_atomic) {
                 qp->s_flags |= RVT_S_WAIT_RDMAR;
                 goto bail;
             }
             qp->s_num_rd_atomic++;
             if (newreq && !(qp->s_flags & RVT_S_UNLIMITED_CREDIT))
                 qp->s_lsn++;
             put_ib_reth_vaddr(
                 wqe->rdma_wr.remote_addr,
                 &ohdr->u.rc.reth);
             ohdr->u.rc.reth.rkey =
                 cpu_to_be32(wqe->rdma_wr.rkey);
             ohdr->u.rc.reth.length = cpu_to_be32(len);
             qp->s_state = OP(RDMA_READ_REQUEST);
             hwords += sizeof(ohdr->u.rc.reth) / sizeof(u32);
             ss = NULL;
             len = 0;
             bth2 |= IB_BTH_REQ_ACK;
             if (++qp->s_cur == qp->s_size)
                 qp->s_cur = 0;
             break;
 
         case IB_WR_TID_RDMA_READ:
             trace_hfi1_tid_read_sender_make_req(qp, newreq);
             wpriv = wqe->priv;
             req = wqe_to_tid_req(wqe);
             trace_hfi1_tid_req_make_req_read(qp, newreq,
                              wqe->wr.opcode,
                              wqe->psn, wqe->lpsn,
                              req);
             delta = cmp_psn(qp->s_psn, wqe->psn);
 
             /*
              * Don't allow more operations to be started
              * than the QP limits allow. We could get here under
              * three conditions; (1) It's a new request; (2) We are
              * sending the second or later segment of a request,
              * but the qp->s_state is set to OP(RDMA_READ_REQUEST)
              * when the last segment of a previous request is
              * received just before this; (3) We are re-sending a
              * request.
              */
             if (qp->s_num_rd_atomic >= qp->s_max_rd_atomic) {
                 qp->s_flags |= RVT_S_WAIT_RDMAR;
                 goto bail;
             }
             if (newreq) {
                 struct tid_rdma_flow *flow =
                     &req->flows[req->setup_head];
 
                 /*
                  * Set up s_sge as it is needed for TID
                  * allocation. However, if the pages have been
                  * walked and mapped, skip it. An earlier try
                  * has failed to allocate the TID entries.
                  */
                 if (!flow->npagesets) {
                     qp->s_sge.sge = wqe->sg_list[0];
                     qp->s_sge.sg_list = wqe->sg_list + 1;
                     qp->s_sge.num_sge = wqe->wr.num_sge;
                     qp->s_sge.total_len = wqe->length;
                     qp->s_len = wqe->length;
                     req->isge = 0;
                     req->clear_tail = req->setup_head;
                     req->flow_idx = req->setup_head;
                     req->state = TID_REQUEST_ACTIVE;
                 }
             } else if (delta == 0) {
                 /* Re-send a request */
                 req->cur_seg = 0;
                 req->comp_seg = 0;
                 req->ack_pending = 0;
                 req->flow_idx = req->clear_tail;
                 req->state = TID_REQUEST_RESEND;
             }
             req->s_next_psn = qp->s_psn;
             /* Read one segment at a time */
             len = min_t(u32, req->seg_len,
                     wqe->length - req->seg_len * req->cur_seg);
             delta = hfi1_build_tid_rdma_read_req(qp, wqe, ohdr,
                                  &bth1, &bth2,
                                  &len);
             if (delta <= 0) {
                 /* Wait for TID space */
                 goto bail;
             }
             if (newreq && !(qp->s_flags & RVT_S_UNLIMITED_CREDIT))
                 qp->s_lsn++;
             hwords += delta;
             ss = &wpriv->ss;
             /* Check if this is the last segment */
             if (req->cur_seg >= req->total_segs &&
                 ++qp->s_cur == qp->s_size)
                 qp->s_cur = 0;
             break;
 
         case IB_WR_ATOMIC_CMP_AND_SWP:
         case IB_WR_ATOMIC_FETCH_AND_ADD:
             /*
              * Don't allow more operations to be started
              * than the QP limits allow.
              */
             if (qp->s_num_rd_atomic >=
                 qp->s_max_rd_atomic) {
                 qp->s_flags |= RVT_S_WAIT_RDMAR;
                 goto bail;
             }
             qp->s_num_rd_atomic++;
             fallthrough;
         case IB_WR_OPFN:
             if (newreq && !(qp->s_flags & RVT_S_UNLIMITED_CREDIT))
                 qp->s_lsn++;
             if (wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
                 wqe->wr.opcode == IB_WR_OPFN) {
                 qp->s_state = OP(COMPARE_SWAP);
                 put_ib_ateth_swap(wqe->atomic_wr.swap,
                           &ohdr->u.atomic_eth);
                 put_ib_ateth_compare(wqe->atomic_wr.compare_add,
                              &ohdr->u.atomic_eth);
             } else {
                 qp->s_state = OP(FETCH_ADD);
                 put_ib_ateth_swap(wqe->atomic_wr.compare_add,
                           &ohdr->u.atomic_eth);
                 put_ib_ateth_compare(0, &ohdr->u.atomic_eth);
             }
             put_ib_ateth_vaddr(wqe->atomic_wr.remote_addr,
                        &ohdr->u.atomic_eth);
             ohdr->u.atomic_eth.rkey = cpu_to_be32(
                 wqe->atomic_wr.rkey);
             hwords += sizeof(struct ib_atomic_eth) / sizeof(u32);
             ss = NULL;
             len = 0;
             bth2 |= IB_BTH_REQ_ACK;
             if (++qp->s_cur == qp->s_size)
                 qp->s_cur = 0;
             break;
 
         default:
             goto bail;
         }
         if (wqe->wr.opcode != IB_WR_TID_RDMA_READ) {
             qp->s_sge.sge = wqe->sg_list[0];
             qp->s_sge.sg_list = wqe->sg_list + 1;
             qp->s_sge.num_sge = wqe->wr.num_sge;
             qp->s_sge.total_len = wqe->length;
             qp->s_len = wqe->length;
         }
         if (newreq) {
             qp->s_tail++;
             if (qp->s_tail >= qp->s_size)
                 qp->s_tail = 0;
         }
         if (wqe->wr.opcode == IB_WR_RDMA_READ ||
             wqe->wr.opcode == IB_WR_TID_RDMA_WRITE)
             qp->s_psn = wqe->lpsn + 1;
         else if (wqe->wr.opcode == IB_WR_TID_RDMA_READ)
             qp->s_psn = req->s_next_psn;
         else
             qp->s_psn++;
         break;
 
     case OP(RDMA_READ_RESPONSE_FIRST):
         /*
          * qp->s_state is normally set to the opcode of the
          * last packet constructed for new requests and therefore
          * is never set to RDMA read response.
          * RDMA_READ_RESPONSE_FIRST is used by the ACK processing
          * thread to indicate a SEND needs to be restarted from an
          * earlier PSN without interfering with the sending thread.
          * See restart_rc().
          */
         qp->s_len = restart_sge(&qp->s_sge, wqe, qp->s_psn, pmtu);
         fallthrough;
     case OP(SEND_FIRST):
         qp->s_state = OP(SEND_MIDDLE);
         fallthrough;
     case OP(SEND_MIDDLE):
         bth2 = mask_psn(qp->s_psn++);
         ss = &qp->s_sge;
         len = qp->s_len;
         if (len > pmtu) {
             len = pmtu;
             middle = HFI1_CAP_IS_KSET(SDMA_AHG);
             break;
         }
         if (wqe->wr.opcode == IB_WR_SEND) {
             qp->s_state = OP(SEND_LAST);
         } else if (wqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
             qp->s_state = OP(SEND_LAST_WITH_IMMEDIATE);
             /* Immediate data comes after the BTH */
             ohdr->u.imm_data = wqe->wr.ex.imm_data;
             hwords += 1;
         } else {
             qp->s_state = OP(SEND_LAST_WITH_INVALIDATE);
             /* invalidate data comes after the BTH */
             ohdr->u.ieth = cpu_to_be32(wqe->wr.ex.invalidate_rkey);
             hwords += 1;
         }
         if (wqe->wr.send_flags & IB_SEND_SOLICITED)
             bth0 |= IB_BTH_SOLICITED;
         bth2 |= IB_BTH_REQ_ACK;
         qp->s_cur++;
         if (qp->s_cur >= qp->s_size)
             qp->s_cur = 0;
         break;
 
     case OP(RDMA_READ_RESPONSE_LAST):
         /*
          * qp->s_state is normally set to the opcode of the
          * last packet constructed for new requests and therefore
          * is never set to RDMA read response.
          * RDMA_READ_RESPONSE_LAST is used by the ACK processing
          * thread to indicate a RDMA write needs to be restarted from
          * an earlier PSN without interfering with the sending thread.
          * See restart_rc().
          */
         qp->s_len = restart_sge(&qp->s_sge, wqe, qp->s_psn, pmtu);
         fallthrough;
     case OP(RDMA_WRITE_FIRST):
         qp->s_state = OP(RDMA_WRITE_MIDDLE);
         fallthrough;
     case OP(RDMA_WRITE_MIDDLE):
         bth2 = mask_psn(qp->s_psn++);
         ss = &qp->s_sge;
         len = qp->s_len;
         if (len > pmtu) {
             len = pmtu;
             middle = HFI1_CAP_IS_KSET(SDMA_AHG);
             break;
         }
         if (wqe->wr.opcode == IB_WR_RDMA_WRITE) {
             qp->s_state = OP(RDMA_WRITE_LAST);
         } else {
             qp->s_state = OP(RDMA_WRITE_LAST_WITH_IMMEDIATE);
             /* Immediate data comes after the BTH */
             ohdr->u.imm_data = wqe->wr.ex.imm_data;
             hwords += 1;
             if (wqe->wr.send_flags & IB_SEND_SOLICITED)
                 bth0 |= IB_BTH_SOLICITED;
         }
         bth2 |= IB_BTH_REQ_ACK;
         qp->s_cur++;
         if (qp->s_cur >= qp->s_size)
             qp->s_cur = 0;
         break;
 
     case OP(RDMA_READ_RESPONSE_MIDDLE):
         /*
          * qp->s_state is normally set to the opcode of the
          * last packet constructed for new requests and therefore
          * is never set to RDMA read response.
          * RDMA_READ_RESPONSE_MIDDLE is used by the ACK processing
          * thread to indicate a RDMA read needs to be restarted from
          * an earlier PSN without interfering with the sending thread.
          * See restart_rc().
          */
         len = (delta_psn(qp->s_psn, wqe->psn)) * pmtu;
         put_ib_reth_vaddr(
             wqe->rdma_wr.remote_addr + len,
             &ohdr->u.rc.reth);
         ohdr->u.rc.reth.rkey =
             cpu_to_be32(wqe->rdma_wr.rkey);
         ohdr->u.rc.reth.length = cpu_to_be32(wqe->length - len);
         qp->s_state = OP(RDMA_READ_REQUEST);
         hwords += sizeof(ohdr->u.rc.reth) / sizeof(u32);
         bth2 = mask_psn(qp->s_psn) | IB_BTH_REQ_ACK;
         qp->s_psn = wqe->lpsn + 1;
         ss = NULL;
         len = 0;
         qp->s_cur++;
         if (qp->s_cur == qp->s_size)
             qp->s_cur = 0;
         break;
 
     case TID_OP(WRITE_RESP):
         /*
          * This value for s_state is used for restarting a TID RDMA
          * WRITE request. See comment in OP(RDMA_READ_RESPONSE_MIDDLE
          * for more).
          */
         req = wqe_to_tid_req(wqe);
         req->state = TID_REQUEST_RESEND;
         rcu_read_lock();
         remote = rcu_dereference(priv->tid_rdma.remote);
         req->comp_seg = delta_psn(qp->s_psn, wqe->psn);
         len = wqe->length - (req->comp_seg * remote->max_len);
         rcu_read_unlock();
 
         bth2 = mask_psn(qp->s_psn);
         hwords += hfi1_build_tid_rdma_write_req(qp, wqe, ohdr, &bth1,
                             &bth2, &len);
         qp->s_psn = wqe->lpsn + 1;
         ss = NULL;
         qp->s_state = TID_OP(WRITE_REQ);
         priv->pending_tid_w_resp += delta_psn(wqe->lpsn, bth2) + 1;
         priv->s_tid_cur = qp->s_cur;
         if (++qp->s_cur == qp->s_size)
             qp->s_cur = 0;
         trace_hfi1_tid_req_make_req_write(qp, 0, wqe->wr.opcode,
                           wqe->psn, wqe->lpsn, req);
         break;
 
     case TID_OP(READ_RESP):
         if (wqe->wr.opcode != IB_WR_TID_RDMA_READ)
             goto bail;
         /* This is used to restart a TID read request */
         req = wqe_to_tid_req(wqe);
         wpriv = wqe->priv;
         /*
          * Back down. The field qp->s_psn has been set to the psn with
          * which the request should be restart. It's OK to use division
          * as this is on the retry path.
          */
         req->cur_seg = delta_psn(qp->s_psn, wqe->psn) / priv->pkts_ps;
 
         /*
          * The following function need to be redefined to return the
          * status to make sure that we find the flow. At the same
          * time, we can use the req->state change to check if the
          * call succeeds or not.
          */
         req->state = TID_REQUEST_RESEND;
         hfi1_tid_rdma_restart_req(qp, wqe, &bth2);
         if (req->state != TID_REQUEST_ACTIVE) {
             /*
              * Failed to find the flow. Release all allocated tid
              * resources.
              */
             hfi1_kern_exp_rcv_clear_all(req);
             hfi1_kern_clear_hw_flow(priv->rcd, qp);
 
             hfi1_trdma_send_complete(qp, wqe, IB_WC_LOC_QP_OP_ERR);
             goto bail;
         }
         req->state = TID_REQUEST_RESEND;
         len = min_t(u32, req->seg_len,
                 wqe->length - req->seg_len * req->cur_seg);
         flow = &req->flows[req->flow_idx];
         len -= flow->sent;
         req->s_next_psn = flow->flow_state.ib_lpsn + 1;
         delta = hfi1_build_tid_rdma_read_packet(wqe, ohdr, &bth1,
                             &bth2, &len);
         if (delta <= 0) {
             /* Wait for TID space */
             goto bail;
         }
         hwords += delta;
         ss = &wpriv->ss;
         /* Check if this is the last segment */
         if (req->cur_seg >= req->total_segs &&
             ++qp->s_cur == qp->s_size)
             qp->s_cur = 0;
         qp->s_psn = req->s_next_psn;
         trace_hfi1_tid_req_make_req_read(qp, 0, wqe->wr.opcode,
                          wqe->psn, wqe->lpsn, req);
         break;
     case TID_OP(READ_REQ):
         req = wqe_to_tid_req(wqe);
         delta = cmp_psn(qp->s_psn, wqe->psn);
         /*
          * If the current WR is not TID RDMA READ, or this is the start
          * of a new request, we need to change the qp->s_state so that
          * the request can be set up properly.
          */
         if (wqe->wr.opcode != IB_WR_TID_RDMA_READ || delta == 0 ||
             qp->s_cur == qp->s_tail) {
             qp->s_state = OP(RDMA_READ_REQUEST);
             if (delta == 0 || qp->s_cur == qp->s_tail)
                 goto check_s_state;
             else
                 goto bail;
         }
 
         /* Rate limiting */
         if (qp->s_num_rd_atomic >= qp->s_max_rd_atomic) {
             qp->s_flags |= RVT_S_WAIT_RDMAR;
             goto bail;
         }
 
         wpriv = wqe->priv;
         /* Read one segment at a time */
         len = min_t(u32, req->seg_len,
                 wqe->length - req->seg_len * req->cur_seg);
         delta = hfi1_build_tid_rdma_read_req(qp, wqe, ohdr, &bth1,
                              &bth2, &len);
         if (delta <= 0) {
             /* Wait for TID space */
             goto bail;
         }
         hwords += delta;
         ss = &wpriv->ss;
         /* Check if this is the last segment */
         if (req->cur_seg >= req->total_segs &&
             ++qp->s_cur == qp->s_size)
             qp->s_cur = 0;
         qp->s_psn = req->s_next_psn;
         trace_hfi1_tid_req_make_req_read(qp, 0, wqe->wr.opcode,
                          wqe->psn, wqe->lpsn, req);
         break;
     }
     qp->s_sending_hpsn = bth2;
     delta = delta_psn(bth2, wqe->psn);
     if (delta && delta % HFI1_PSN_CREDIT == 0 &&
         wqe->wr.opcode != IB_WR_TID_RDMA_WRITE)
         bth2 |= IB_BTH_REQ_ACK;
     if (qp->s_flags & RVT_S_SEND_ONE) {
         qp->s_flags &= ~RVT_S_SEND_ONE;
         qp->s_flags |= RVT_S_WAIT_ACK;
         bth2 |= IB_BTH_REQ_ACK;
     }
     qp->s_len -= len;
     ps->s_txreq->hdr_dwords = hwords;
     ps->s_txreq->sde = priv->s_sde;
     ps->s_txreq->ss = ss;
     ps->s_txreq->s_cur_size = len;
     hfi1_make_ruc_header(
         qp,
         ohdr,
         bth0 | (qp->s_state << 24),
         bth1,
         bth2,
         middle,
         ps);
     return 1;
 
 done_free_tx:
     hfi1_put_txreq(ps->s_txreq);
     ps->s_txreq = NULL;
     return 1;
 
 bail:
     hfi1_put_txreq(ps->s_txreq);
 
 bail_no_tx:
     ps->s_txreq = NULL;
     qp->s_flags &= ~RVT_S_BUSY;
     /*
      * If we didn't get a txreq, the QP will be woken up later to try
      * again. Set the flags to indicate which work item to wake
      * up.
      */
     iowait_set_flag(&priv->s_iowait, IOWAIT_PENDING_IB);
     return 0;
 }
 
 static inline void hfi1_make_bth_aeth(struct rvt_qp *qp,
                       struct ib_other_headers *ohdr,
                       u32 bth0, u32 bth1)
 {
     if (qp->r_nak_state)
         ohdr->u.aeth = cpu_to_be32((qp->r_msn & IB_MSN_MASK) |
                         (qp->r_nak_state <<
                          IB_AETH_CREDIT_SHIFT));
     else
         ohdr->u.aeth = rvt_compute_aeth(qp);
 
     ohdr->bth[0] = cpu_to_be32(bth0);
     ohdr->bth[1] = cpu_to_be32(bth1 | qp->remote_qpn);
     ohdr->bth[2] = cpu_to_be32(mask_psn(qp->r_ack_psn));
 }
 
 static inline void hfi1_queue_rc_ack(struct hfi1_packet *packet, bool is_fecn)
 {
     struct rvt_qp *qp = packet->qp;
     struct hfi1_ibport *ibp;
     unsigned long flags;
 
     spin_lock_irqsave(&qp->s_lock, flags);
     if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK))
         goto unlock;
     ibp = rcd_to_iport(packet->rcd);
     this_cpu_inc(*ibp->rvp.rc_qacks);
     qp->s_flags |= RVT_S_ACK_PENDING | RVT_S_RESP_PENDING;
     qp->s_nak_state = qp->r_nak_state;
     qp->s_ack_psn = qp->r_ack_psn;
     if (is_fecn)
         qp->s_flags |= RVT_S_ECN;
 
     /* Schedule the send tasklet. */
     hfi1_schedule_send(qp);
 unlock:
     spin_unlock_irqrestore(&qp->s_lock, flags);
 }
 
 static inline void hfi1_make_rc_ack_9B(struct hfi1_packet *packet,
                        struct hfi1_opa_header *opa_hdr,
                        u8 sc5, bool is_fecn,
                        u64 *pbc_flags, u32 *hwords,
                        u32 *nwords)
 {
     struct rvt_qp *qp = packet->qp;
     struct hfi1_ibport *ibp = rcd_to_iport(packet->rcd);
     struct hfi1_pportdata *ppd = ppd_from_ibp(ibp);
     struct ib_header *hdr = &opa_hdr->ibh;
     struct ib_other_headers *ohdr;
     u16 lrh0 = HFI1_LRH_BTH;
     u16 pkey;
     u32 bth0, bth1;
 
     opa_hdr->hdr_type = HFI1_PKT_TYPE_9B;
     ohdr = &hdr->u.oth;
     /* header size in 32-bit words LRH+BTH+AETH = (8+12+4)/4 */
     *hwords = 6;
 
     if (unlikely(rdma_ah_get_ah_flags(&qp->remote_ah_attr) & IB_AH_GRH)) {
         *hwords += hfi1_make_grh(ibp, &hdr->u.l.grh,
                      rdma_ah_read_grh(&qp->remote_ah_attr),
                      *hwords - 2, SIZE_OF_CRC);
         ohdr = &hdr->u.l.oth;
         lrh0 = HFI1_LRH_GRH;
     }
     /* set PBC_DC_INFO bit (aka SC[4]) in pbc_flags */
     *pbc_flags |= ((!!(sc5 & 0x10)) << PBC_DC_INFO_SHIFT);
 
     /* read pkey_index w/o lock (its atomic) */
     pkey = hfi1_get_pkey(ibp, qp->s_pkey_index);
 
     lrh0 |= (sc5 & IB_SC_MASK) << IB_SC_SHIFT |
         (rdma_ah_get_sl(&qp->remote_ah_attr) & IB_SL_MASK) <<
             IB_SL_SHIFT;
 
     hfi1_make_ib_hdr(hdr, lrh0, *hwords + SIZE_OF_CRC,
              opa_get_lid(rdma_ah_get_dlid(&qp->remote_ah_attr), 9B),
              ppd->lid | rdma_ah_get_path_bits(&qp->remote_ah_attr));
 
     bth0 = pkey | (OP(ACKNOWLEDGE) << 24);
     if (qp->s_mig_state == IB_MIG_MIGRATED)
         bth0 |= IB_BTH_MIG_REQ;
     bth1 = (!!is_fecn) << IB_BECN_SHIFT;
     /*
      * Inline ACKs go out without the use of the Verbs send engine, so
      * we need to set the STL Verbs Extended bit here
      */
     bth1 |= HFI1_CAP_IS_KSET(OPFN) << IB_BTHE_E_SHIFT;
     hfi1_make_bth_aeth(qp, ohdr, bth0, bth1);
 }
 
 static inline void hfi1_make_rc_ack_16B(struct hfi1_packet *packet,
                     struct hfi1_opa_header *opa_hdr,
                     u8 sc5, bool is_fecn,
                     u64 *pbc_flags, u32 *hwords,
                     u32 *nwords)
 {
     struct rvt_qp *qp = packet->qp;
     struct hfi1_ibport *ibp = rcd_to_iport(packet->rcd);
     struct hfi1_pportdata *ppd = ppd_from_ibp(ibp);
     struct hfi1_16b_header *hdr = &opa_hdr->opah;
     struct ib_other_headers *ohdr;
     u32 bth0, bth1 = 0;
     u16 len, pkey;
     bool becn = is_fecn;
     u8 l4 = OPA_16B_L4_IB_LOCAL;
     u8 extra_bytes;
 
     opa_hdr->hdr_type = HFI1_PKT_TYPE_16B;
     ohdr = &hdr->u.oth;
     /* header size in 32-bit words 16B LRH+BTH+AETH = (16+12+4)/4 */
     *hwords = 8;
     extra_bytes = hfi1_get_16b_padding(*hwords << 2, 0);
     *nwords = SIZE_OF_CRC + ((extra_bytes + SIZE_OF_LT) >> 2);
 
     if (unlikely(rdma_ah_get_ah_flags(&qp->remote_ah_attr) & IB_AH_GRH) &&
         hfi1_check_mcast(rdma_ah_get_dlid(&qp->remote_ah_attr))) {
         *hwords += hfi1_make_grh(ibp, &hdr->u.l.grh,
                      rdma_ah_read_grh(&qp->remote_ah_attr),
                      *hwords - 4, *nwords);
         ohdr = &hdr->u.l.oth;
         l4 = OPA_16B_L4_IB_GLOBAL;
     }
     *pbc_flags |= PBC_PACKET_BYPASS | PBC_INSERT_BYPASS_ICRC;
 
     /* read pkey_index w/o lock (its atomic) */
     pkey = hfi1_get_pkey(ibp, qp->s_pkey_index);
 
     /* Convert dwords to flits */
     len = (*hwords + *nwords) >> 1;
 
     hfi1_make_16b_hdr(hdr, ppd->lid |
               (rdma_ah_get_path_bits(&qp->remote_ah_attr) &
               ((1 << ppd->lmc) - 1)),
               opa_get_lid(rdma_ah_get_dlid(&qp->remote_ah_attr),
                       16B), len, pkey, becn, 0, l4, sc5);
 
     bth0 = pkey | (OP(ACKNOWLEDGE) << 24);
     bth0 |= extra_bytes << 20;
     if (qp->s_mig_state == IB_MIG_MIGRATED)
         bth1 = OPA_BTH_MIG_REQ;
     hfi1_make_bth_aeth(qp, ohdr, bth0, bth1);
 }
 
 typedef void (*hfi1_make_rc_ack)(struct hfi1_packet *packet,
                  struct hfi1_opa_header *opa_hdr,
                  u8 sc5, bool is_fecn,
                  u64 *pbc_flags, u32 *hwords,
                  u32 *nwords);
 
 /* We support only two types - 9B and 16B for now */
 static const hfi1_make_rc_ack hfi1_make_rc_ack_tbl[2] = {
     [HFI1_PKT_TYPE_9B] = &hfi1_make_rc_ack_9B,
     [HFI1_PKT_TYPE_16B] = &hfi1_make_rc_ack_16B
 };
 
 /*
  * hfi1_send_rc_ack - Construct an ACK packet and send it
  *
  * This is called from hfi1_rc_rcv() and handle_receive_interrupt().
  * Note that RDMA reads and atomics are handled in the
  * send side QP state and send engine.
  */
 void hfi1_send_rc_ack(struct hfi1_packet *packet, bool is_fecn)
 {
     struct hfi1_ctxtdata *rcd = packet->rcd;
     struct rvt_qp *qp = packet->qp;
     struct hfi1_ibport *ibp = rcd_to_iport(rcd);
     struct hfi1_qp_priv *priv = qp->priv;
     struct hfi1_pportdata *ppd = ppd_from_ibp(ibp);
     u8 sc5 = ibp->sl_to_sc[rdma_ah_get_sl(&qp->remote_ah_attr)];
     u64 pbc, pbc_flags = 0;
     u32 hwords = 0;
     u32 nwords = 0;
     u32 plen;
     struct pio_buf *pbuf;
     struct hfi1_opa_header opa_hdr;
 
     /* clear the defer count */
     qp->r_adefered = 0;
 
     /* Don't send ACK or NAK if a RDMA read or atomic is pending. */
     if (qp->s_flags & RVT_S_RESP_PENDING) {
         hfi1_queue_rc_ack(packet, is_fecn);
         return;
     }
 
     /* Ensure s_rdma_ack_cnt changes are committed */
     if (qp->s_rdma_ack_cnt) {
         hfi1_queue_rc_ack(packet, is_fecn);
         return;
     }
 
     /* Don't try to send ACKs if the link isn't ACTIVE */
     if (driver_lstate(ppd) != IB_PORT_ACTIVE)
         return;
 
     /* Make the appropriate header */
     hfi1_make_rc_ack_tbl[priv->hdr_type](packet, &opa_hdr, sc5, is_fecn,
                          &pbc_flags, &hwords, &nwords);
 
     plen = 2 /* PBC */ + hwords + nwords;
     pbc = create_pbc(ppd, pbc_flags, qp->srate_mbps,
              sc_to_vlt(ppd->dd, sc5), plen);
     pbuf = sc_buffer_alloc(rcd->sc, plen, NULL, NULL);
     if (IS_ERR_OR_NULL(pbuf)) {
         /*
          * We have no room to send at the moment.  Pass
          * responsibility for sending the ACK to the send engine
          * so that when enough buffer space becomes available,
          * the ACK is sent ahead of other outgoing packets.
          */
         hfi1_queue_rc_ack(packet, is_fecn);
         return;
     }
     trace_ack_output_ibhdr(dd_from_ibdev(qp->ibqp.device),
                    &opa_hdr, ib_is_sc5(sc5));
 
     /* write the pbc and data */
     ppd->dd->pio_inline_send(ppd->dd, pbuf, pbc,
                  (priv->hdr_type == HFI1_PKT_TYPE_9B ?
                  (void *)&opa_hdr.ibh :
                  (void *)&opa_hdr.opah), hwords);
     return;
 }
 
 /**
  * update_num_rd_atomic - update the qp->s_num_rd_atomic
  * @qp: the QP
  * @psn: the packet sequence number to restart at
  * @wqe: the wqe
  *
  * This is called from reset_psn() to update qp->s_num_rd_atomic
  * for the current wqe.
  * Called at interrupt level with the QP s_lock held.
  */
 static void update_num_rd_atomic(struct rvt_qp *qp, u32 psn,
                  struct rvt_swqe *wqe)
 {
     u32 opcode = wqe->wr.opcode;
 
     if (opcode == IB_WR_RDMA_READ ||
         opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
         opcode == IB_WR_ATOMIC_FETCH_AND_ADD) {
         qp->s_num_rd_atomic++;
     } else if (opcode == IB_WR_TID_RDMA_READ) {
         struct tid_rdma_request *req = wqe_to_tid_req(wqe);
         struct hfi1_qp_priv *priv = qp->priv;
 
         if (cmp_psn(psn, wqe->lpsn) <= 0) {
             u32 cur_seg;
 
             cur_seg = (psn - wqe->psn) / priv->pkts_ps;
             req->ack_pending = cur_seg - req->comp_seg;
             priv->pending_tid_r_segs += req->ack_pending;
             qp->s_num_rd_atomic += req->ack_pending;
             trace_hfi1_tid_req_update_num_rd_atomic(qp, 0,
                                 wqe->wr.opcode,
                                 wqe->psn,
                                 wqe->lpsn,
                                 req);
         } else {
             priv->pending_tid_r_segs += req->total_segs;
             qp->s_num_rd_atomic += req->total_segs;
         }
     }
 }
 
 /**
  * reset_psn - reset the QP state to send starting from PSN
  * @qp: the QP
  * @psn: the packet sequence number to restart at
  *
  * This is called from hfi1_rc_rcv() to process an incoming RC ACK
  * for the given QP.
  * Called at interrupt level with the QP s_lock held.
  */
 static void reset_psn(struct rvt_qp *qp, u32 psn)
 {
     u32 n = qp->s_acked;
     struct rvt_swqe *wqe = rvt_get_swqe_ptr(qp, n);
     u32 opcode;
     struct hfi1_qp_priv *priv = qp->priv;
 
     lockdep_assert_held(&qp->s_lock);
     qp->s_cur = n;
     priv->pending_tid_r_segs = 0;
     priv->pending_tid_w_resp = 0;
     qp->s_num_rd_atomic = 0;
 
     /*
      * If we are starting the request from the beginning,
      * let the normal send code handle initialization.
      */
     if (cmp_psn(psn, wqe->psn) <= 0) {
         qp->s_state = OP(SEND_LAST);
         goto done;
     }
     update_num_rd_atomic(qp, psn, wqe);
 
     /* Find the work request opcode corresponding to the given PSN. */
     for (;;) {
         int diff;
 
         if (++n == qp->s_size)
             n = 0;
         if (n == qp->s_tail)
             break;
         wqe = rvt_get_swqe_ptr(qp, n);
         diff = cmp_psn(psn, wqe->psn);
         if (diff < 0) {
             /* Point wqe back to the previous one*/
             wqe = rvt_get_swqe_ptr(qp, qp->s_cur);
             break;
         }
         qp->s_cur = n;
         /*
          * If we are starting the request from the beginning,
          * let the normal send code handle initialization.
          */
         if (diff == 0) {
             qp->s_state = OP(SEND_LAST);
             goto done;
         }
 
         update_num_rd_atomic(qp, psn, wqe);
     }
     opcode = wqe->wr.opcode;
 
     /*
      * Set the state to restart in the middle of a request.
      * Don't change the s_sge, s_cur_sge, or s_cur_size.
      * See hfi1_make_rc_req().
      */
     switch (opcode) {
     case IB_WR_SEND:
     case IB_WR_SEND_WITH_IMM:
         qp->s_state = OP(RDMA_READ_RESPONSE_FIRST);
         break;
 
     case IB_WR_RDMA_WRITE:
     case IB_WR_RDMA_WRITE_WITH_IMM:
         qp->s_state = OP(RDMA_READ_RESPONSE_LAST);
         break;
 
     case IB_WR_TID_RDMA_WRITE:
         qp->s_state = TID_OP(WRITE_RESP);
         break;
 
     case IB_WR_RDMA_READ:
         qp->s_state = OP(RDMA_READ_RESPONSE_MIDDLE);
         break;
 
     case IB_WR_TID_RDMA_READ:
         qp->s_state = TID_OP(READ_RESP);
         break;
 
     default:
         /*
          * This case shouldn't happen since its only
          * one PSN per req.
          */
         qp->s_state = OP(SEND_LAST);
     }
 done:
     priv->s_flags &= ~HFI1_S_TID_WAIT_INTERLCK;
     qp->s_psn = psn;
     /*
      * Set RVT_S_WAIT_PSN as rc_complete() may start the timer
      * asynchronously before the send engine can get scheduled.
      * Doing it in hfi1_make_rc_req() is too late.
      */
     if ((cmp_psn(qp->s_psn, qp->s_sending_hpsn) <= 0) &&
         (cmp_psn(qp->s_sending_psn, qp->s_sending_hpsn) <= 0))
         qp->s_flags |= RVT_S_WAIT_PSN;
     qp->s_flags &= ~HFI1_S_AHG_VALID;
     trace_hfi1_sender_reset_psn(qp);
 }
 
 /*
  * Back up requester to resend the last un-ACKed request.
  * The QP r_lock and s_lock should be held and interrupts disabled.
  */
 void hfi1_restart_rc(struct rvt_qp *qp, u32 psn, int wait)
 {
     struct hfi1_qp_priv *priv = qp->priv;
     struct rvt_swqe *wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
     struct hfi1_ibport *ibp;
 
     lockdep_assert_held(&qp->r_lock);
     lockdep_assert_held(&qp->s_lock);
     trace_hfi1_sender_restart_rc(qp);
     if (qp->s_retry == 0) {
         if (qp->s_mig_state == IB_MIG_ARMED) {
             hfi1_migrate_qp(qp);
             qp->s_retry = qp->s_retry_cnt;
         } else if (qp->s_last == qp->s_acked) {
             /*
              * We need special handling for the OPFN request WQEs as
              * they are not allowed to generate real user errors
              */
             if (wqe->wr.opcode == IB_WR_OPFN) {
                 struct hfi1_ibport *ibp =
                     to_iport(qp->ibqp.device, qp->port_num);
                 /*
                  * Call opfn_conn_reply() with capcode and
                  * remaining data as 0 to close out the
                  * current request
                  */
                 opfn_conn_reply(qp, priv->opfn.curr);
                 wqe = do_rc_completion(qp, wqe, ibp);
                 qp->s_flags &= ~RVT_S_WAIT_ACK;
             } else {
                 trace_hfi1_tid_write_sender_restart_rc(qp, 0);
                 if (wqe->wr.opcode == IB_WR_TID_RDMA_READ) {
                     struct tid_rdma_request *req;
 
                     req = wqe_to_tid_req(wqe);
                     hfi1_kern_exp_rcv_clear_all(req);
                     hfi1_kern_clear_hw_flow(priv->rcd, qp);
                 }
 
                 hfi1_trdma_send_complete(qp, wqe,
                              IB_WC_RETRY_EXC_ERR);
                 rvt_error_qp(qp, IB_WC_WR_FLUSH_ERR);
             }
             return;
         } else { /* need to handle delayed completion */
             return;
         }
     } else {
         qp->s_retry--;
     }
 
     ibp = to_iport(qp->ibqp.device, qp->port_num);
     if (wqe->wr.opcode == IB_WR_RDMA_READ ||
         wqe->wr.opcode == IB_WR_TID_RDMA_READ)
         ibp->rvp.n_rc_resends++;
     else
         ibp->rvp.n_rc_resends += delta_psn(qp->s_psn, psn);
 
     qp->s_flags &= ~(RVT_S_WAIT_FENCE | RVT_S_WAIT_RDMAR |
              RVT_S_WAIT_SSN_CREDIT | RVT_S_WAIT_PSN |
              RVT_S_WAIT_ACK | HFI1_S_WAIT_TID_RESP);
     if (wait)
         qp->s_flags |= RVT_S_SEND_ONE;
     reset_psn(qp, psn);
 }
 
 /*
  * Set qp->s_sending_psn to the next PSN after the given one.
  * This would be psn+1 except when RDMA reads or TID RDMA ops
  * are present.
  */
 static void reset_sending_psn(struct rvt_qp *qp, u32 psn)
 {
     struct rvt_swqe *wqe;
     u32 n = qp->s_last;
 
     lockdep_assert_held(&qp->s_lock);
     /* Find the work request corresponding to the given PSN. */
     for (;;) {
         wqe = rvt_get_swqe_ptr(qp, n);
         if (cmp_psn(psn, wqe->lpsn) <= 0) {
             if (wqe->wr.opcode == IB_WR_RDMA_READ ||
                 wqe->wr.opcode == IB_WR_TID_RDMA_READ ||
                 wqe->wr.opcode == IB_WR_TID_RDMA_WRITE)
                 qp->s_sending_psn = wqe->lpsn + 1;
             else
                 qp->s_sending_psn = psn + 1;
             break;
         }
         if (++n == qp->s_size)
             n = 0;
         if (n == qp->s_tail)
             break;
     }
 }
 
 /**
  * hfi1_rc_verbs_aborted - handle abort status
  * @qp: the QP
  * @opah: the opa header
  *
  * This code modifies both ACK bit in BTH[2]
  * and the s_flags to go into send one mode.
  *
  * This serves to throttle the send engine to only
  * send a single packet in the likely case the
  * a link has gone down.
  */
 void hfi1_rc_verbs_aborted(struct rvt_qp *qp, struct hfi1_opa_header *opah)
 {
     struct ib_other_headers *ohdr = hfi1_get_rc_ohdr(opah);
     u8 opcode = ib_bth_get_opcode(ohdr);
     u32 psn;
 
     /* ignore responses */
     if ((opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
          opcode <= OP(ATOMIC_ACKNOWLEDGE)) ||
         opcode == TID_OP(READ_RESP) ||
         opcode == TID_OP(WRITE_RESP))
         return;
 
     psn = ib_bth_get_psn(ohdr) | IB_BTH_REQ_ACK;
     ohdr->bth[2] = cpu_to_be32(psn);
     qp->s_flags |= RVT_S_SEND_ONE;
 }
 
 /*
  * This should be called with the QP s_lock held and interrupts disabled.
  */
 void hfi1_rc_send_complete(struct rvt_qp *qp, struct hfi1_opa_header *opah)
 {
     struct ib_other_headers *ohdr;
     struct hfi1_qp_priv *priv = qp->priv;
     struct rvt_swqe *wqe;
     u32 opcode, head, tail;
     u32 psn;
     struct tid_rdma_request *req;
 
     lockdep_assert_held(&qp->s_lock);
     if (!(ib_rvt_state_ops[qp->state] & RVT_SEND_OR_FLUSH_OR_RECV_OK))
         return;
 
     ohdr = hfi1_get_rc_ohdr(opah);
     opcode = ib_bth_get_opcode(ohdr);
     if ((opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
          opcode <= OP(ATOMIC_ACKNOWLEDGE)) ||
         opcode == TID_OP(READ_RESP) ||
         opcode == TID_OP(WRITE_RESP)) {
         WARN_ON(!qp->s_rdma_ack_cnt);
         qp->s_rdma_ack_cnt--;
         return;
     }
 
     psn = ib_bth_get_psn(ohdr);
     /*
      * Don't attempt to reset the sending PSN for packets in the
      * KDETH PSN space since the PSN does not match anything.
      */
     if (opcode != TID_OP(WRITE_DATA) &&
         opcode != TID_OP(WRITE_DATA_LAST) &&
         opcode != TID_OP(ACK) && opcode != TID_OP(RESYNC))
         reset_sending_psn(qp, psn);
 
     /* Handle TID RDMA WRITE packets differently */
     if (opcode >= TID_OP(WRITE_REQ) &&
         opcode <= TID_OP(WRITE_DATA_LAST)) {
         head = priv->s_tid_head;
         tail = priv->s_tid_cur;
         /*
          * s_tid_cur is set to s_tid_head in the case, where
          * a new TID RDMA request is being started and all
          * previous ones have been completed.
          * Therefore, we need to do a secondary check in order
          * to properly determine whether we should start the
          * RC timer.
          */
         wqe = rvt_get_swqe_ptr(qp, tail);
         req = wqe_to_tid_req(wqe);
         if (head == tail && req->comp_seg < req->total_segs) {
             if (tail == 0)
                 tail = qp->s_size - 1;
             else
                 tail -= 1;
         }
     } else {
         head = qp->s_tail;
         tail = qp->s_acked;
     }
 
     /*
      * Start timer after a packet requesting an ACK has been sent and
      * there are still requests that haven't been acked.
      */
     if ((psn & IB_BTH_REQ_ACK) && tail != head &&
         opcode != TID_OP(WRITE_DATA) && opcode != TID_OP(WRITE_DATA_LAST) &&
         opcode != TID_OP(RESYNC) &&
         !(qp->s_flags &
           (RVT_S_TIMER | RVT_S_WAIT_RNR | RVT_S_WAIT_PSN)) &&
         (ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK)) {
         if (opcode == TID_OP(READ_REQ))
             rvt_add_retry_timer_ext(qp, priv->timeout_shift);
         else
             rvt_add_retry_timer(qp);
     }
 
     /* Start TID RDMA ACK timer */
     if ((opcode == TID_OP(WRITE_DATA) ||
          opcode == TID_OP(WRITE_DATA_LAST) ||
          opcode == TID_OP(RESYNC)) &&
         (psn & IB_BTH_REQ_ACK) &&
         !(priv->s_flags & HFI1_S_TID_RETRY_TIMER) &&
         (ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK)) {
         /*
          * The TID RDMA ACK packet could be received before this
          * function is called. Therefore, add the timer only if TID
          * RDMA ACK packets are actually pending.
          */
         wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
         req = wqe_to_tid_req(wqe);
         if (wqe->wr.opcode == IB_WR_TID_RDMA_WRITE &&
             req->ack_seg < req->cur_seg)
             hfi1_add_tid_retry_timer(qp);
     }
 
     while (qp->s_last != qp->s_acked) {
         wqe = rvt_get_swqe_ptr(qp, qp->s_last);
         if (cmp_psn(wqe->lpsn, qp->s_sending_psn) >= 0 &&
             cmp_psn(qp->s_sending_psn, qp->s_sending_hpsn) <= 0)
             break;
         trdma_clean_swqe(qp, wqe);
         trace_hfi1_qp_send_completion(qp, wqe, qp->s_last);
         rvt_qp_complete_swqe(qp,
                      wqe,
                      ib_hfi1_wc_opcode[wqe->wr.opcode],
                      IB_WC_SUCCESS);
     }
     /*
      * If we were waiting for sends to complete before re-sending,
      * and they are now complete, restart sending.
      */
     trace_hfi1_sendcomplete(qp, psn);
     if (qp->s_flags & RVT_S_WAIT_PSN &&
         cmp_psn(qp->s_sending_psn, qp->s_sending_hpsn) > 0) {
         qp->s_flags &= ~RVT_S_WAIT_PSN;
         qp->s_sending_psn = qp->s_psn;
         qp->s_sending_hpsn = qp->s_psn - 1;
         hfi1_schedule_send(qp);
     }
 }
 
 static inline void update_last_psn(struct rvt_qp *qp, u32 psn)
 {
     qp->s_last_psn = psn;
 }
 
 /*
  * Generate a SWQE completion.
  * This is similar to hfi1_send_complete but has to check to be sure
  * that the SGEs are not being referenced if the SWQE is being resent.
  */
 struct rvt_swqe *do_rc_completion(struct rvt_qp *qp,
                   struct rvt_swqe *wqe,
                   struct hfi1_ibport *ibp)
 {
     struct hfi1_qp_priv *priv = qp->priv;
 
     lockdep_assert_held(&qp->s_lock);
     /*
      * Don't decrement refcount and don't generate a
      * completion if the SWQE is being resent until the send
      * is finished.
      */
     trace_hfi1_rc_completion(qp, wqe->lpsn);
     if (cmp_psn(wqe->lpsn, qp->s_sending_psn) < 0 ||
         cmp_psn(qp->s_sending_psn, qp->s_sending_hpsn) > 0) {
         trdma_clean_swqe(qp, wqe);
         trace_hfi1_qp_send_completion(qp, wqe, qp->s_last);
         rvt_qp_complete_swqe(qp,
                      wqe,
                      ib_hfi1_wc_opcode[wqe->wr.opcode],
                      IB_WC_SUCCESS);
     } else {
         struct hfi1_pportdata *ppd = ppd_from_ibp(ibp);
 
         this_cpu_inc(*ibp->rvp.rc_delayed_comp);
         /*
          * If send progress not running attempt to progress
          * SDMA queue.
          */
         if (ppd->dd->flags & HFI1_HAS_SEND_DMA) {
             struct sdma_engine *engine;
             u8 sl = rdma_ah_get_sl(&qp->remote_ah_attr);
             u8 sc5;
 
             /* For now use sc to find engine */
             sc5 = ibp->sl_to_sc[sl];
             engine = qp_to_sdma_engine(qp, sc5);
             sdma_engine_progress_schedule(engine);
         }
     }
 
     qp->s_retry = qp->s_retry_cnt;
     /*
      * Don't update the last PSN if the request being completed is
      * a TID RDMA WRITE request.
      * Completion of the TID RDMA WRITE requests are done by the
      * TID RDMA ACKs and as such could be for a request that has
      * already been ACKed as far as the IB state machine is
      * concerned.
      */
     if (wqe->wr.opcode != IB_WR_TID_RDMA_WRITE)
         update_last_psn(qp, wqe->lpsn);
 
     /*
      * If we are completing a request which is in the process of
      * being resent, we can stop re-sending it since we know the
      * responder has already seen it.
      */
     if (qp->s_acked == qp->s_cur) {
         if (++qp->s_cur >= qp->s_size)
             qp->s_cur = 0;
         qp->s_acked = qp->s_cur;
         wqe = rvt_get_swqe_ptr(qp, qp->s_cur);
         if (qp->s_acked != qp->s_tail) {
             qp->s_state = OP(SEND_LAST);
             qp->s_psn = wqe->psn;
         }
     } else {
         if (++qp->s_acked >= qp->s_size)
             qp->s_acked = 0;
         if (qp->state == IB_QPS_SQD && qp->s_acked == qp->s_cur)
             qp->s_draining = 0;
         wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
     }
     if (priv->s_flags & HFI1_S_TID_WAIT_INTERLCK) {
         priv->s_flags &= ~HFI1_S_TID_WAIT_INTERLCK;
         hfi1_schedule_send(qp);
     }
     return wqe;
 }
 
 static void set_restart_qp(struct rvt_qp *qp, struct hfi1_ctxtdata *rcd)
 {
     /* Retry this request. */
     if (!(qp->r_flags & RVT_R_RDMAR_SEQ)) {
         qp->r_flags |= RVT_R_RDMAR_SEQ;
         hfi1_restart_rc(qp, qp->s_last_psn + 1, 0);
         if (list_empty(&qp->rspwait)) {
             qp->r_flags |= RVT_R_RSP_SEND;
             rvt_get_qp(qp);
             list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
         }
     }
 }
 
 /**
  * update_qp_retry_state - Update qp retry state.
  * @qp: the QP
  * @psn: the packet sequence number of the TID RDMA WRITE RESP.
  * @spsn:  The start psn for the given TID RDMA WRITE swqe.
  * @lpsn:  The last psn for the given TID RDMA WRITE swqe.
  *
  * This function is called to update the qp retry state upon
  * receiving a TID WRITE RESP after the qp is scheduled to retry
  * a request.
  */
 static void update_qp_retry_state(struct rvt_qp *qp, u32 psn, u32 spsn,
                   u32 lpsn)
 {
     struct hfi1_qp_priv *qpriv = qp->priv;
 
     qp->s_psn = psn + 1;
     /*
      * If this is the first TID RDMA WRITE RESP packet for the current
      * request, change the s_state so that the retry will be processed
      * correctly. Similarly, if this is the last TID RDMA WRITE RESP
      * packet, change the s_state and advance the s_cur.
      */
     if (cmp_psn(psn, lpsn) >= 0) {
         qp->s_cur = qpriv->s_tid_cur + 1;
         if (qp->s_cur >= qp->s_size)
             qp->s_cur = 0;
         qp->s_state = TID_OP(WRITE_REQ);
     } else  if (!cmp_psn(psn, spsn)) {
         qp->s_cur = qpriv->s_tid_cur;
         qp->s_state = TID_OP(WRITE_RESP);
     }
 }
 
 /*
  * do_rc_ack - process an incoming RC ACK
  * @qp: the QP the ACK came in on
  * @psn: the packet sequence number of the ACK
  * @opcode: the opcode of the request that resulted in the ACK
  *
  * This is called from rc_rcv_resp() to process an incoming RC ACK
  * for the given QP.
  * May be called at interrupt level, with the QP s_lock held.
  * Returns 1 if OK, 0 if current operation should be aborted (NAK).
  */
 int do_rc_ack(struct rvt_qp *qp, u32 aeth, u32 psn, int opcode,
           u64 val, struct hfi1_ctxtdata *rcd)
 {
     struct hfi1_ibport *ibp;
     enum ib_wc_status status;
     struct hfi1_qp_priv *qpriv = qp->priv;
     struct rvt_swqe *wqe;
     int ret = 0;
     u32 ack_psn;
     int diff;
     struct rvt_dev_info *rdi;
 
     lockdep_assert_held(&qp->s_lock);
     /*
      * Note that NAKs implicitly ACK outstanding SEND and RDMA write
      * requests and implicitly NAK RDMA read and atomic requests issued
      * before the NAK'ed request.  The MSN won't include the NAK'ed
      * request but will include an ACK'ed request(s).
      */
     ack_psn = psn;
     if (aeth >> IB_AETH_NAK_SHIFT)
         ack_psn--;
     wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
     ibp = rcd_to_iport(rcd);
 
     /*
      * The MSN might be for a later WQE than the PSN indicates so
      * only complete WQEs that the PSN finishes.
      */
     while ((diff = delta_psn(ack_psn, wqe->lpsn)) >= 0) {
         /*
          * RDMA_READ_RESPONSE_ONLY is a special case since
          * we want to generate completion events for everything
          * before the RDMA read, copy the data, then generate
          * the completion for the read.
          */
         if (wqe->wr.opcode == IB_WR_RDMA_READ &&
             opcode == OP(RDMA_READ_RESPONSE_ONLY) &&
             diff == 0) {
             ret = 1;
             goto bail_stop;
         }
         /*
          * If this request is a RDMA read or atomic, and the ACK is
          * for a later operation, this ACK NAKs the RDMA read or
          * atomic.  In other words, only a RDMA_READ_LAST or ONLY
          * can ACK a RDMA read and likewise for atomic ops.  Note
          * that the NAK case can only happen if relaxed ordering is
          * used and requests are sent after an RDMA read or atomic
          * is sent but before the response is received.
          */
         if ((wqe->wr.opcode == IB_WR_RDMA_READ &&
              (opcode != OP(RDMA_READ_RESPONSE_LAST) || diff != 0)) ||
             (wqe->wr.opcode == IB_WR_TID_RDMA_READ &&
              (opcode != TID_OP(READ_RESP) || diff != 0)) ||
             ((wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
               wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) &&
              (opcode != OP(ATOMIC_ACKNOWLEDGE) || diff != 0)) ||
             (wqe->wr.opcode == IB_WR_TID_RDMA_WRITE &&
              (delta_psn(psn, qp->s_last_psn) != 1))) {
             set_restart_qp(qp, rcd);
             /*
              * No need to process the ACK/NAK since we are
              * restarting an earlier request.
              */
             goto bail_stop;
         }
         if (wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
             wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) {
             u64 *vaddr = wqe->sg_list[0].vaddr;
             *vaddr = val;
         }
         if (wqe->wr.opcode == IB_WR_OPFN)
             opfn_conn_reply(qp, val);
 
         if (qp->s_num_rd_atomic &&
             (wqe->wr.opcode == IB_WR_RDMA_READ ||
              wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
              wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)) {
             qp->s_num_rd_atomic--;
             /* Restart sending task if fence is complete */
             if ((qp->s_flags & RVT_S_WAIT_FENCE) &&
                 !qp->s_num_rd_atomic) {
                 qp->s_flags &= ~(RVT_S_WAIT_FENCE |
                          RVT_S_WAIT_ACK);
                 hfi1_schedule_send(qp);
             } else if (qp->s_flags & RVT_S_WAIT_RDMAR) {
                 qp->s_flags &= ~(RVT_S_WAIT_RDMAR |
                          RVT_S_WAIT_ACK);
                 hfi1_schedule_send(qp);
             }
         }
 
         /*
          * TID RDMA WRITE requests will be completed by the TID RDMA
          * ACK packet handler (see tid_rdma.c).
          */
         if (wqe->wr.opcode == IB_WR_TID_RDMA_WRITE)
             break;
 
         wqe = do_rc_completion(qp, wqe, ibp);
         if (qp->s_acked == qp->s_tail)
             break;
     }
 
     trace_hfi1_rc_ack_do(qp, aeth, psn, wqe);
     trace_hfi1_sender_do_rc_ack(qp);
     switch (aeth >> IB_AETH_NAK_SHIFT) {
     case 0:         /* ACK */
         this_cpu_inc(*ibp->rvp.rc_acks);
         if (wqe->wr.opcode == IB_WR_TID_RDMA_READ) {
             if (wqe_to_tid_req(wqe)->ack_pending)
                 rvt_mod_retry_timer_ext(qp,
                             qpriv->timeout_shift);
             else
                 rvt_stop_rc_timers(qp);
         } else if (qp->s_acked != qp->s_tail) {
             struct rvt_swqe *__w = NULL;
 
             if (qpriv->s_tid_cur != HFI1_QP_WQE_INVALID)
                 __w = rvt_get_swqe_ptr(qp, qpriv->s_tid_cur);
 
             /*
              * Stop timers if we've received all of the TID RDMA
              * WRITE * responses.
              */
             if (__w && __w->wr.opcode == IB_WR_TID_RDMA_WRITE &&
                 opcode == TID_OP(WRITE_RESP)) {
                 /*
                  * Normally, the loop above would correctly
                  * process all WQEs from s_acked onward and
                  * either complete them or check for correct
                  * PSN sequencing.
                  * However, for TID RDMA, due to pipelining,
                  * the response may not be for the request at
                  * s_acked so the above look would just be
                  * skipped. This does not allow for checking
                  * the PSN sequencing. It has to be done
                  * separately.
                  */
                 if (cmp_psn(psn, qp->s_last_psn + 1)) {
                     set_restart_qp(qp, rcd);
                     goto bail_stop;
                 }
                 /*
                  * If the psn is being resent, stop the
                  * resending.
                  */
                 if (qp->s_cur != qp->s_tail &&
                     cmp_psn(qp->s_psn, psn) <= 0)
                     update_qp_retry_state(qp, psn,
                                   __w->psn,
                                   __w->lpsn);
                 else if (--qpriv->pending_tid_w_resp)
                     rvt_mod_retry_timer(qp);
                 else
                     rvt_stop_rc_timers(qp);
             } else {
                 /*
                  * We are expecting more ACKs so
                  * mod the retry timer.
                  */
                 rvt_mod_retry_timer(qp);
                 /*
                  * We can stop re-sending the earlier packets
                  * and continue with the next packet the
                  * receiver wants.
                  */
                 if (cmp_psn(qp->s_psn, psn) <= 0)
                     reset_psn(qp, psn + 1);
             }
         } else {
             /* No more acks - kill all timers */
             rvt_stop_rc_timers(qp);
             if (cmp_psn(qp->s_psn, psn) <= 0) {
                 qp->s_state = OP(SEND_LAST);
                 qp->s_psn = psn + 1;
             }
         }
         if (qp->s_flags & RVT_S_WAIT_ACK) {
             qp->s_flags &= ~RVT_S_WAIT_ACK;
             hfi1_schedule_send(qp);
         }
         rvt_get_credit(qp, aeth);
         qp->s_rnr_retry = qp->s_rnr_retry_cnt;
         qp->s_retry = qp->s_retry_cnt;
         /*
          * If the current request is a TID RDMA WRITE request and the
          * response is not a TID RDMA WRITE RESP packet, s_last_psn
          * can't be advanced.
          */
         if (wqe->wr.opcode == IB_WR_TID_RDMA_WRITE &&
             opcode != TID_OP(WRITE_RESP) &&
             cmp_psn(psn, wqe->psn) >= 0)
             return 1;
         update_last_psn(qp, psn);
         return 1;
 
     case 1:         /* RNR NAK */
         ibp->rvp.n_rnr_naks++;
         if (qp->s_acked == qp->s_tail)
             goto bail_stop;
         if (qp->s_flags & RVT_S_WAIT_RNR)
             goto bail_stop;
         rdi = ib_to_rvt(qp->ibqp.device);
         if (!(rdi->post_parms[wqe->wr.opcode].flags &
                RVT_OPERATION_IGN_RNR_CNT)) {
             if (qp->s_rnr_retry == 0) {
                 status = IB_WC_RNR_RETRY_EXC_ERR;
                 goto class_b;
             }
             if (qp->s_rnr_retry_cnt < 7 && qp->s_rnr_retry_cnt > 0)
                 qp->s_rnr_retry--;
         }
 
         /*
          * The last valid PSN is the previous PSN. For TID RDMA WRITE
          * request, s_last_psn should be incremented only when a TID
          * RDMA WRITE RESP is received to avoid skipping lost TID RDMA
          * WRITE RESP packets.
          */
         if (wqe->wr.opcode == IB_WR_TID_RDMA_WRITE) {
             reset_psn(qp, qp->s_last_psn + 1);
         } else {
             update_last_psn(qp, psn - 1);
             reset_psn(qp, psn);
         }
 
         ibp->rvp.n_rc_resends += delta_psn(qp->s_psn, psn);
         qp->s_flags &= ~(RVT_S_WAIT_SSN_CREDIT | RVT_S_WAIT_ACK);
         rvt_stop_rc_timers(qp);
         rvt_add_rnr_timer(qp, aeth);
         return 0;
 
     case 3:         /* NAK */
         if (qp->s_acked == qp->s_tail)
             goto bail_stop;
         /* The last valid PSN is the previous PSN. */
         update_last_psn(qp, psn - 1);
         switch ((aeth >> IB_AETH_CREDIT_SHIFT) &
             IB_AETH_CREDIT_MASK) {
         case 0: /* PSN sequence error */
             ibp->rvp.n_seq_naks++;
             /*
              * Back up to the responder's expected PSN.
              * Note that we might get a NAK in the middle of an
              * RDMA READ response which terminates the RDMA
              * READ.
              */
             hfi1_restart_rc(qp, psn, 0);
             hfi1_schedule_send(qp);
             break;
 
         case 1: /* Invalid Request */
             status = IB_WC_REM_INV_REQ_ERR;
             ibp->rvp.n_other_naks++;
             goto class_b;
 
         case 2: /* Remote Access Error */
             status = IB_WC_REM_ACCESS_ERR;
             ibp->rvp.n_other_naks++;
             goto class_b;
 
         case 3: /* Remote Operation Error */
             status = IB_WC_REM_OP_ERR;
             ibp->rvp.n_other_naks++;
 class_b:
             if (qp->s_last == qp->s_acked) {
                 if (wqe->wr.opcode == IB_WR_TID_RDMA_READ)
                     hfi1_kern_read_tid_flow_free(qp);
 
                 hfi1_trdma_send_complete(qp, wqe, status);
                 rvt_error_qp(qp, IB_WC_WR_FLUSH_ERR);
             }
             break;
 
         default:
             /* Ignore other reserved NAK error codes */
             goto reserved;
         }
         qp->s_retry = qp->s_retry_cnt;
         qp->s_rnr_retry = qp->s_rnr_retry_cnt;
         goto bail_stop;
 
     default:                /* 2: reserved */
 reserved:
         /* Ignore reserved NAK codes. */
         goto bail_stop;
     }
     /* cannot be reached  */
 bail_stop:
     rvt_stop_rc_timers(qp);
     return ret;
 }
 
 /*
  * We have seen an out of sequence RDMA read middle or last packet.
  * This ACKs SENDs and RDMA writes up to the first RDMA read or atomic SWQE.
  */
 static void rdma_seq_err(struct rvt_qp *qp, struct hfi1_ibport *ibp, u32 psn,
              struct hfi1_ctxtdata *rcd)
 {
     struct rvt_swqe *wqe;
 
     lockdep_assert_held(&qp->s_lock);
     /* Remove QP from retry timer */
     rvt_stop_rc_timers(qp);
 
     wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
 
     while (cmp_psn(psn, wqe->lpsn) > 0) {
         if (wqe->wr.opcode == IB_WR_RDMA_READ ||
             wqe->wr.opcode == IB_WR_TID_RDMA_READ ||
             wqe->wr.opcode == IB_WR_TID_RDMA_WRITE ||
             wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
             wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)
             break;
         wqe = do_rc_completion(qp, wqe, ibp);
     }
 
     ibp->rvp.n_rdma_seq++;
     qp->r_flags |= RVT_R_RDMAR_SEQ;
     hfi1_restart_rc(qp, qp->s_last_psn + 1, 0);
     if (list_empty(&qp->rspwait)) {
         qp->r_flags |= RVT_R_RSP_SEND;
         rvt_get_qp(qp);
         list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
     }
 }
 
 /**
  * rc_rcv_resp - process an incoming RC response packet
  * @packet: data packet information
  *
  * This is called from hfi1_rc_rcv() to process an incoming RC response
  * packet for the given QP.
  * Called at interrupt level.
  */
 static void rc_rcv_resp(struct hfi1_packet *packet)
 {
     struct hfi1_ctxtdata *rcd = packet->rcd;
     void *data = packet->payload;
     u32 tlen = packet->tlen;
     struct rvt_qp *qp = packet->qp;
     struct hfi1_ibport *ibp;
     struct ib_other_headers *ohdr = packet->ohdr;
     struct rvt_swqe *wqe;
     enum ib_wc_status status;
     unsigned long flags;
     int diff;
     u64 val;
     u32 aeth;
     u32 psn = ib_bth_get_psn(packet->ohdr);
     u32 pmtu = qp->pmtu;
     u16 hdrsize = packet->hlen;
     u8 opcode = packet->opcode;
     u8 pad = packet->pad;
     u8 extra_bytes = pad + packet->extra_byte + (SIZE_OF_CRC << 2);
 
     spin_lock_irqsave(&qp->s_lock, flags);
     trace_hfi1_ack(qp, psn);
 
     /* Ignore invalid responses. */
     if (cmp_psn(psn, READ_ONCE(qp->s_next_psn)) >= 0)
         goto ack_done;
 
     /* Ignore duplicate responses. */
     diff = cmp_psn(psn, qp->s_last_psn);
     if (unlikely(diff <= 0)) {
         /* Update credits for "ghost" ACKs */
         if (diff == 0 && opcode == OP(ACKNOWLEDGE)) {
             aeth = be32_to_cpu(ohdr->u.aeth);
             if ((aeth >> IB_AETH_NAK_SHIFT) == 0)
                 rvt_get_credit(qp, aeth);
         }
         goto ack_done;
     }
 
     /*
      * Skip everything other than the PSN we expect, if we are waiting
      * for a reply to a restarted RDMA read or atomic op.
      */
     if (qp->r_flags & RVT_R_RDMAR_SEQ) {
         if (cmp_psn(psn, qp->s_last_psn + 1) != 0)
             goto ack_done;
         qp->r_flags &= ~RVT_R_RDMAR_SEQ;
     }
 
     if (unlikely(qp->s_acked == qp->s_tail))
         goto ack_done;
     wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
     status = IB_WC_SUCCESS;
 
     switch (opcode) {
     case OP(ACKNOWLEDGE):
     case OP(ATOMIC_ACKNOWLEDGE):
     case OP(RDMA_READ_RESPONSE_FIRST):
         aeth = be32_to_cpu(ohdr->u.aeth);
         if (opcode == OP(ATOMIC_ACKNOWLEDGE))
             val = ib_u64_get(&ohdr->u.at.atomic_ack_eth);
         else
             val = 0;
         if (!do_rc_ack(qp, aeth, psn, opcode, val, rcd) ||
             opcode != OP(RDMA_READ_RESPONSE_FIRST))
             goto ack_done;
         wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
         if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
             goto ack_op_err;
         /*
          * If this is a response to a resent RDMA read, we
          * have to be careful to copy the data to the right
          * location.
          */
         qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
                           wqe, psn, pmtu);
         goto read_middle;
 
     case OP(RDMA_READ_RESPONSE_MIDDLE):
         /* no AETH, no ACK */
         if (unlikely(cmp_psn(psn, qp->s_last_psn + 1)))
             goto ack_seq_err;
         if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
             goto ack_op_err;
 read_middle:
         if (unlikely(tlen != (hdrsize + pmtu + extra_bytes)))
             goto ack_len_err;
         if (unlikely(pmtu >= qp->s_rdma_read_len))
             goto ack_len_err;
 
         /*
          * We got a response so update the timeout.
          * 4.096 usec. * (1 << qp->timeout)
          */
         rvt_mod_retry_timer(qp);
         if (qp->s_flags & RVT_S_WAIT_ACK) {
             qp->s_flags &= ~RVT_S_WAIT_ACK;
             hfi1_schedule_send(qp);
         }
 
         if (opcode == OP(RDMA_READ_RESPONSE_MIDDLE))
             qp->s_retry = qp->s_retry_cnt;
 
         /*
          * Update the RDMA receive state but do the copy w/o
          * holding the locks and blocking interrupts.
          */
         qp->s_rdma_read_len -= pmtu;
         update_last_psn(qp, psn);
         spin_unlock_irqrestore(&qp->s_lock, flags);
         rvt_copy_sge(qp, &qp->s_rdma_read_sge,
                  data, pmtu, false, false);
         goto bail;
 
     case OP(RDMA_READ_RESPONSE_ONLY):
         aeth = be32_to_cpu(ohdr->u.aeth);
         if (!do_rc_ack(qp, aeth, psn, opcode, 0, rcd))
             goto ack_done;
         /*
          * Check that the data size is >= 0 && <= pmtu.
          * Remember to account for ICRC (4).
          */
         if (unlikely(tlen < (hdrsize + extra_bytes)))
             goto ack_len_err;
         /*
          * If this is a response to a resent RDMA read, we
          * have to be careful to copy the data to the right
          * location.
          */
         wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
         qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
                           wqe, psn, pmtu);
         goto read_last;
 
     case OP(RDMA_READ_RESPONSE_LAST):
         /* ACKs READ req. */
         if (unlikely(cmp_psn(psn, qp->s_last_psn + 1)))
             goto ack_seq_err;
         if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
             goto ack_op_err;
         /*
          * Check that the data size is >= 1 && <= pmtu.
          * Remember to account for ICRC (4).
          */
         if (unlikely(tlen <= (hdrsize + extra_bytes)))
             goto ack_len_err;
 read_last:
         tlen -= hdrsize + extra_bytes;
         if (unlikely(tlen != qp->s_rdma_read_len))
             goto ack_len_err;
         aeth = be32_to_cpu(ohdr->u.aeth);
         rvt_copy_sge(qp, &qp->s_rdma_read_sge,
                  data, tlen, false, false);
         WARN_ON(qp->s_rdma_read_sge.num_sge);
         (void)do_rc_ack(qp, aeth, psn,
                  OP(RDMA_READ_RESPONSE_LAST), 0, rcd);
         goto ack_done;
     }
 
 ack_op_err:
     status = IB_WC_LOC_QP_OP_ERR;
     goto ack_err;
 
 ack_seq_err:
     ibp = rcd_to_iport(rcd);
     rdma_seq_err(qp, ibp, psn, rcd);
     goto ack_done;
 
 ack_len_err:
     status = IB_WC_LOC_LEN_ERR;
 ack_err:
     if (qp->s_last == qp->s_acked) {
         rvt_send_complete(qp, wqe, status);
         rvt_error_qp(qp, IB_WC_WR_FLUSH_ERR);
     }
 ack_done:
     spin_unlock_irqrestore(&qp->s_lock, flags);
 bail:
     return;
 }
 
 static inline void rc_cancel_ack(struct rvt_qp *qp)
 {
     qp->r_adefered = 0;
     if (list_empty(&qp->rspwait))
         return;
     list_del_init(&qp->rspwait);
     qp->r_flags &= ~RVT_R_RSP_NAK;
     rvt_put_qp(qp);
 }
 
 /**
  * rc_rcv_error - process an incoming duplicate or error RC packet
  * @ohdr: the other headers for this packet
  * @data: the packet data
  * @qp: the QP for this packet
  * @opcode: the opcode for this packet
  * @psn: the packet sequence number for this packet
  * @diff: the difference between the PSN and the expected PSN
  * @rcd: the receive context
  *
  * This is called from hfi1_rc_rcv() to process an unexpected
  * incoming RC packet for the given QP.
  * Called at interrupt level.
  * Return 1 if no more processing is needed; otherwise return 0 to
  * schedule a response to be sent.
  */
 static noinline int rc_rcv_error(struct ib_other_headers *ohdr, void *data,
                  struct rvt_qp *qp, u32 opcode, u32 psn,
                  int diff, struct hfi1_ctxtdata *rcd)
 {
     struct hfi1_ibport *ibp = rcd_to_iport(rcd);
     struct rvt_ack_entry *e;
     unsigned long flags;
     u8 prev;
     u8 mra; /* most recent ACK */
     bool old_req;
 
     trace_hfi1_rcv_error(qp, psn);
     if (diff > 0) {
         /*
          * Packet sequence error.
          * A NAK will ACK earlier sends and RDMA writes.
          * Don't queue the NAK if we already sent one.
          */
         if (!qp->r_nak_state) {
             ibp->rvp.n_rc_seqnak++;
             qp->r_nak_state = IB_NAK_PSN_ERROR;
             /* Use the expected PSN. */
             qp->r_ack_psn = qp->r_psn;
             /*
              * Wait to send the sequence NAK until all packets
              * in the receive queue have been processed.
              * Otherwise, we end up propagating congestion.
              */
             rc_defered_ack(rcd, qp);
         }
         goto done;
     }
 
     /*
      * Handle a duplicate request.  Don't re-execute SEND, RDMA
      * write or atomic op.  Don't NAK errors, just silently drop
      * the duplicate request.  Note that r_sge, r_len, and
      * r_rcv_len may be in use so don't modify them.
      *
      * We are supposed to ACK the earliest duplicate PSN but we
      * can coalesce an outstanding duplicate ACK.  We have to
      * send the earliest so that RDMA reads can be restarted at
      * the requester's expected PSN.
      *
      * First, find where this duplicate PSN falls within the
      * ACKs previously sent.
      * old_req is true if there is an older response that is scheduled
      * to be sent before sending this one.
      */
     e = NULL;
     old_req = true;
     ibp->rvp.n_rc_dupreq++;
 
     spin_lock_irqsave(&qp->s_lock, flags);
 
     e = find_prev_entry(qp, psn, &prev, &mra, &old_req);
 
     switch (opcode) {
     case OP(RDMA_READ_REQUEST): {
         struct ib_reth *reth;
         u32 offset;
         u32 len;
 
         /*
          * If we didn't find the RDMA read request in the ack queue,
          * we can ignore this request.
          */
         if (!e || e->opcode != OP(RDMA_READ_REQUEST))
             goto unlock_done;
         /* RETH comes after BTH */
         reth = &ohdr->u.rc.reth;
         /*
          * Address range must be a subset of the original
          * request and start on pmtu boundaries.
          * We reuse the old ack_queue slot since the requester
          * should not back up and request an earlier PSN for the
          * same request.
          */
         offset = delta_psn(psn, e->psn) * qp->pmtu;
         len = be32_to_cpu(reth->length);
         if (unlikely(offset + len != e->rdma_sge.sge_length))
             goto unlock_done;
         release_rdma_sge_mr(e);
         if (len != 0) {
             u32 rkey = be32_to_cpu(reth->rkey);
             u64 vaddr = get_ib_reth_vaddr(reth);
             int ok;
 
             ok = rvt_rkey_ok(qp, &e->rdma_sge, len, vaddr, rkey,
                      IB_ACCESS_REMOTE_READ);
             if (unlikely(!ok))
                 goto unlock_done;
         } else {
             e->rdma_sge.vaddr = NULL;
             e->rdma_sge.length = 0;
             e->rdma_sge.sge_length = 0;
         }
         e->psn = psn;
         if (old_req)
             goto unlock_done;
         if (qp->s_acked_ack_queue == qp->s_tail_ack_queue)
             qp->s_acked_ack_queue = prev;
         qp->s_tail_ack_queue = prev;
         break;
     }
 
     case OP(COMPARE_SWAP):
     case OP(FETCH_ADD): {
         /*
          * If we didn't find the atomic request in the ack queue
          * or the send engine is already backed up to send an
          * earlier entry, we can ignore this request.
          */
         if (!e || e->opcode != (u8)opcode || old_req)
             goto unlock_done;
         if (qp->s_tail_ack_queue == qp->s_acked_ack_queue)
             qp->s_acked_ack_queue = prev;
         qp->s_tail_ack_queue = prev;
         break;
     }
 
     default:
         /*
          * Ignore this operation if it doesn't request an ACK
          * or an earlier RDMA read or atomic is going to be resent.
          */
         if (!(psn & IB_BTH_REQ_ACK) || old_req)
             goto unlock_done;
         /*
          * Resend the most recent ACK if this request is
          * after all the previous RDMA reads and atomics.
          */
         if (mra == qp->r_head_ack_queue) {
             spin_unlock_irqrestore(&qp->s_lock, flags);
             qp->r_nak_state = 0;
             qp->r_ack_psn = qp->r_psn - 1;
             goto send_ack;
         }
 
         /*
          * Resend the RDMA read or atomic op which
          * ACKs this duplicate request.
          */
         if (qp->s_tail_ack_queue == qp->s_acked_ack_queue)
             qp->s_acked_ack_queue = mra;
         qp->s_tail_ack_queue = mra;
         break;
     }
     qp->s_ack_state = OP(ACKNOWLEDGE);
     qp->s_flags |= RVT_S_RESP_PENDING;
     qp->r_nak_state = 0;
     hfi1_schedule_send(qp);
 
 unlock_done:
     spin_unlock_irqrestore(&qp->s_lock, flags);
 done:
     return 1;
 
 send_ack:
     return 0;
 }
 
 static void log_cca_event(struct hfi1_pportdata *ppd, u8 sl, u32 rlid,
               u32 lqpn, u32 rqpn, u8 svc_type)
 {
     struct opa_hfi1_cong_log_event_internal *cc_event;
     unsigned long flags;
 
     if (sl >= OPA_MAX_SLS)
         return;
 
     spin_lock_irqsave(&ppd->cc_log_lock, flags);
 
     ppd->threshold_cong_event_map[sl / 8] |= 1 << (sl % 8);
     ppd->threshold_event_counter++;
 
     cc_event = &ppd->cc_events[ppd->cc_log_idx++];
     if (ppd->cc_log_idx == OPA_CONG_LOG_ELEMS)
         ppd->cc_log_idx = 0;
     cc_event->lqpn = lqpn & RVT_QPN_MASK;
     cc_event->rqpn = rqpn & RVT_QPN_MASK;
     cc_event->sl = sl;
     cc_event->svc_type = svc_type;
     cc_event->rlid = rlid;
     /* keep timestamp in units of 1.024 usec */
     cc_event->timestamp = ktime_get_ns() / 1024;
 
     spin_unlock_irqrestore(&ppd->cc_log_lock, flags);
 }
 
 void process_becn(struct hfi1_pportdata *ppd, u8 sl, u32 rlid, u32 lqpn,
           u32 rqpn, u8 svc_type)
 {
     struct cca_timer *cca_timer;
     u16 ccti, ccti_incr, ccti_timer, ccti_limit;
     u8 trigger_threshold;
     struct cc_state *cc_state;
     unsigned long flags;
 
     if (sl >= OPA_MAX_SLS)
         return;
 
     cc_state = get_cc_state(ppd);
 
     if (!cc_state)
         return;
 
     /*
      * 1) increase CCTI (for this SL)
      * 2) select IPG (i.e., call set_link_ipg())
      * 3) start timer
      */
     ccti_limit = cc_state->cct.ccti_limit;
     ccti_incr = cc_state->cong_setting.entries[sl].ccti_increase;
     ccti_timer = cc_state->cong_setting.entries[sl].ccti_timer;
     trigger_threshold =
         cc_state->cong_setting.entries[sl].trigger_threshold;
 
     spin_lock_irqsave(&ppd->cca_timer_lock, flags);
 
     cca_timer = &ppd->cca_timer[sl];
     if (cca_timer->ccti < ccti_limit) {
         if (cca_timer->ccti + ccti_incr <= ccti_limit)
             cca_timer->ccti += ccti_incr;
         else
             cca_timer->ccti = ccti_limit;
         set_link_ipg(ppd);
     }
 
     ccti = cca_timer->ccti;
 
     if (!hrtimer_active(&cca_timer->hrtimer)) {
         /* ccti_timer is in units of 1.024 usec */
         unsigned long nsec = 1024 * ccti_timer;
 
         hrtimer_start(&cca_timer->hrtimer, ns_to_ktime(nsec),
                   HRTIMER_MODE_REL_PINNED);
     }
 
     spin_unlock_irqrestore(&ppd->cca_timer_lock, flags);
 
     if ((trigger_threshold != 0) && (ccti >= trigger_threshold))
         log_cca_event(ppd, sl, rlid, lqpn, rqpn, svc_type);
 }
 
 /**
  * hfi1_rc_rcv - process an incoming RC packet
  * @packet: data packet information
  *
  * This is called from qp_rcv() to process an incoming RC packet
  * for the given QP.
  * May be called at interrupt level.
  */
 void hfi1_rc_rcv(struct hfi1_packet *packet)
 {
     struct hfi1_ctxtdata *rcd = packet->rcd;
     void *data = packet->payload;
     u32 tlen = packet->tlen;
     struct rvt_qp *qp = packet->qp;
     struct hfi1_qp_priv *qpriv = qp->priv;
     struct hfi1_ibport *ibp = rcd_to_iport(rcd);
     struct ib_other_headers *ohdr = packet->ohdr;
     u32 opcode = packet->opcode;
     u32 hdrsize = packet->hlen;
     u32 psn = ib_bth_get_psn(packet->ohdr);
     u32 pad = packet->pad;
     struct ib_wc wc;
     u32 pmtu = qp->pmtu;
     int diff;
     struct ib_reth *reth;
     unsigned long flags;
     int ret;
     bool copy_last = false, fecn;
     u32 rkey;
     u8 extra_bytes = pad + packet->extra_byte + (SIZE_OF_CRC << 2);
 
     lockdep_assert_held(&qp->r_lock);
 
     if (hfi1_ruc_check_hdr(ibp, packet))
         return;
 
     fecn = process_ecn(qp, packet);
     opfn_trigger_conn_request(qp, be32_to_cpu(ohdr->bth[1]));
 
     /*
      * Process responses (ACKs) before anything else.  Note that the
      * packet sequence number will be for something in the send work
      * queue rather than the expected receive packet sequence number.
      * In other words, this QP is the requester.
      */
     if (opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
         opcode <= OP(ATOMIC_ACKNOWLEDGE)) {
         rc_rcv_resp(packet);
         return;
     }
 
     /* Compute 24 bits worth of difference. */
     diff = delta_psn(psn, qp->r_psn);
     if (unlikely(diff)) {
         if (rc_rcv_error(ohdr, data, qp, opcode, psn, diff, rcd))
             return;
         goto send_ack;
     }
 
     /* Check for opcode sequence errors. */
     switch (qp->r_state) {
     case OP(SEND_FIRST):
     case OP(SEND_MIDDLE):
         if (opcode == OP(SEND_MIDDLE) ||
             opcode == OP(SEND_LAST) ||
             opcode == OP(SEND_LAST_WITH_IMMEDIATE) ||
             opcode == OP(SEND_LAST_WITH_INVALIDATE))
             break;
         goto nack_inv;
 
     case OP(RDMA_WRITE_FIRST):
     case OP(RDMA_WRITE_MIDDLE):
         if (opcode == OP(RDMA_WRITE_MIDDLE) ||
             opcode == OP(RDMA_WRITE_LAST) ||
             opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
             break;
         goto nack_inv;
 
     default:
         if (opcode == OP(SEND_MIDDLE) ||
             opcode == OP(SEND_LAST) ||
             opcode == OP(SEND_LAST_WITH_IMMEDIATE) ||
             opcode == OP(SEND_LAST_WITH_INVALIDATE) ||
             opcode == OP(RDMA_WRITE_MIDDLE) ||
             opcode == OP(RDMA_WRITE_LAST) ||
             opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
             goto nack_inv;
         /*
          * Note that it is up to the requester to not send a new
          * RDMA read or atomic operation before receiving an ACK
          * for the previous operation.
          */
         break;
     }
 
     if (qp->state == IB_QPS_RTR && !(qp->r_flags & RVT_R_COMM_EST))
         rvt_comm_est(qp);
 
     /* OK, process the packet. */
     switch (opcode) {
     case OP(SEND_FIRST):
         ret = rvt_get_rwqe(qp, false);
         if (ret < 0)
             goto nack_op_err;
         if (!ret)
             goto rnr_nak;
         qp->r_rcv_len = 0;
         fallthrough;
     case OP(SEND_MIDDLE):
     case OP(RDMA_WRITE_MIDDLE):
 send_middle:
         /* Check for invalid length PMTU or posted rwqe len. */
         /*
          * There will be no padding for 9B packet but 16B packets
          * will come in with some padding since we always add
          * CRC and LT bytes which will need to be flit aligned
          */
         if (unlikely(tlen != (hdrsize + pmtu + extra_bytes)))
             goto nack_inv;
         qp->r_rcv_len += pmtu;
         if (unlikely(qp->r_rcv_len > qp->r_len))
             goto nack_inv;
         rvt_copy_sge(qp, &qp->r_sge, data, pmtu, true, false);
         break;
 
     case OP(RDMA_WRITE_LAST_WITH_IMMEDIATE):
         /* consume RWQE */
         ret = rvt_get_rwqe(qp, true);
         if (ret < 0)
             goto nack_op_err;
         if (!ret)
             goto rnr_nak;
         goto send_last_imm;
 
     case OP(SEND_ONLY):
     case OP(SEND_ONLY_WITH_IMMEDIATE):
     case OP(SEND_ONLY_WITH_INVALIDATE):
         ret = rvt_get_rwqe(qp, false);
         if (ret < 0)
             goto nack_op_err;
         if (!ret)
             goto rnr_nak;
         qp->r_rcv_len = 0;
         if (opcode == OP(SEND_ONLY))
             goto no_immediate_data;
         if (opcode == OP(SEND_ONLY_WITH_INVALIDATE))
             goto send_last_inv;
         fallthrough;    /* for SEND_ONLY_WITH_IMMEDIATE */
     case OP(SEND_LAST_WITH_IMMEDIATE):
 send_last_imm:
         wc.ex.imm_data = ohdr->u.imm_data;
         wc.wc_flags = IB_WC_WITH_IMM;
         goto send_last;
     case OP(SEND_LAST_WITH_INVALIDATE):
 send_last_inv:
         rkey = be32_to_cpu(ohdr->u.ieth);
         if (rvt_invalidate_rkey(qp, rkey))
             goto no_immediate_data;
         wc.ex.invalidate_rkey = rkey;
         wc.wc_flags = IB_WC_WITH_INVALIDATE;
         goto send_last;
     case OP(RDMA_WRITE_LAST):
         copy_last = rvt_is_user_qp(qp);
         fallthrough;
     case OP(SEND_LAST):
 no_immediate_data:
         wc.wc_flags = 0;
         wc.ex.imm_data = 0;
 send_last:
         /* Check for invalid length. */
         /* LAST len should be >= 1 */
         if (unlikely(tlen < (hdrsize + extra_bytes)))
             goto nack_inv;
         /* Don't count the CRC(and padding and LT byte for 16B). */
         tlen -= (hdrsize + extra_bytes);
         wc.byte_len = tlen + qp->r_rcv_len;
         if (unlikely(wc.byte_len > qp->r_len))
             goto nack_inv;
         rvt_copy_sge(qp, &qp->r_sge, data, tlen, true, copy_last);
         rvt_put_ss(&qp->r_sge);
         qp->r_msn++;
         if (!__test_and_clear_bit(RVT_R_WRID_VALID, &qp->r_aflags))
             break;
         wc.wr_id = qp->r_wr_id;
         wc.status = IB_WC_SUCCESS;
         if (opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE) ||
             opcode == OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE))
             wc.opcode = IB_WC_RECV_RDMA_WITH_IMM;
         else
             wc.opcode = IB_WC_RECV;
         wc.qp = &qp->ibqp;
         wc.src_qp = qp->remote_qpn;
         wc.slid = rdma_ah_get_dlid(&qp->remote_ah_attr) & U16_MAX;
         /*
          * It seems that IB mandates the presence of an SL in a
          * work completion only for the UD transport (see section
          * 11.4.2 of IBTA Vol. 1).
          *
          * However, the way the SL is chosen below is consistent
          * with the way that IB/qib works and is trying avoid
          * introducing incompatibilities.
          *
          * See also OPA Vol. 1, section 9.7.6, and table 9-17.
          */
         wc.sl = rdma_ah_get_sl(&qp->remote_ah_attr);
         /* zero fields that are N/A */
         wc.vendor_err = 0;
         wc.pkey_index = 0;
         wc.dlid_path_bits = 0;
         wc.port_num = 0;
         /* Signal completion event if the solicited bit is set. */
         rvt_recv_cq(qp, &wc, ib_bth_is_solicited(ohdr));
         break;
 
     case OP(RDMA_WRITE_ONLY):
         copy_last = rvt_is_user_qp(qp);
         fallthrough;
     case OP(RDMA_WRITE_FIRST):
     case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE):
         if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_WRITE)))
             goto nack_inv;
         /* consume RWQE */
         reth = &ohdr->u.rc.reth;
         qp->r_len = be32_to_cpu(reth->length);
         qp->r_rcv_len = 0;
         qp->r_sge.sg_list = NULL;
         if (qp->r_len != 0) {
             u32 rkey = be32_to_cpu(reth->rkey);
             u64 vaddr = get_ib_reth_vaddr(reth);
             int ok;
 
             /* Check rkey & NAK */
             ok = rvt_rkey_ok(qp, &qp->r_sge.sge, qp->r_len, vaddr,
                      rkey, IB_ACCESS_REMOTE_WRITE);
             if (unlikely(!ok))
                 goto nack_acc;
             qp->r_sge.num_sge = 1;
         } else {
             qp->r_sge.num_sge = 0;
             qp->r_sge.sge.mr = NULL;
             qp->r_sge.sge.vaddr = NULL;
             qp->r_sge.sge.length = 0;
             qp->r_sge.sge.sge_length = 0;
         }
         if (opcode == OP(RDMA_WRITE_FIRST))
             goto send_middle;
         else if (opcode == OP(RDMA_WRITE_ONLY))
             goto no_immediate_data;
         ret = rvt_get_rwqe(qp, true);
         if (ret < 0)
             goto nack_op_err;
         if (!ret) {
             /* peer will send again */
             rvt_put_ss(&qp->r_sge);
             goto rnr_nak;
         }
         wc.ex.imm_data = ohdr->u.rc.imm_data;
         wc.wc_flags = IB_WC_WITH_IMM;
         goto send_last;
 
     case OP(RDMA_READ_REQUEST): {
         struct rvt_ack_entry *e;
         u32 len;
         u8 next;
 
         if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_READ)))
             goto nack_inv;
         next = qp->r_head_ack_queue + 1;
         /* s_ack_queue is size rvt_size_atomic()+1 so use > not >= */
         if (next > rvt_size_atomic(ib_to_rvt(qp->ibqp.device)))
             next = 0;
         spin_lock_irqsave(&qp->s_lock, flags);
         if (unlikely(next == qp->s_acked_ack_queue)) {
             if (!qp->s_ack_queue[next].sent)
                 goto nack_inv_unlck;
             update_ack_queue(qp, next);
         }
         e = &qp->s_ack_queue[qp->r_head_ack_queue];
         release_rdma_sge_mr(e);
         reth = &ohdr->u.rc.reth;
         len = be32_to_cpu(reth->length);
         if (len) {
             u32 rkey = be32_to_cpu(reth->rkey);
             u64 vaddr = get_ib_reth_vaddr(reth);
             int ok;
 
             /* Check rkey & NAK */
             ok = rvt_rkey_ok(qp, &e->rdma_sge, len, vaddr,
                      rkey, IB_ACCESS_REMOTE_READ);
             if (unlikely(!ok))
                 goto nack_acc_unlck;
             /*
              * Update the next expected PSN.  We add 1 later
              * below, so only add the remainder here.
              */
             qp->r_psn += rvt_div_mtu(qp, len - 1);
         } else {
             e->rdma_sge.mr = NULL;
             e->rdma_sge.vaddr = NULL;
             e->rdma_sge.length = 0;
             e->rdma_sge.sge_length = 0;
         }
         e->opcode = opcode;
         e->sent = 0;
         e->psn = psn;
         e->lpsn = qp->r_psn;
         /*
          * We need to increment the MSN here instead of when we
          * finish sending the result since a duplicate request would
          * increment it more than once.
          */
         qp->r_msn++;
         qp->r_psn++;
         qp->r_state = opcode;
         qp->r_nak_state = 0;
         qp->r_head_ack_queue = next;
         qpriv->r_tid_alloc = qp->r_head_ack_queue;
 
         /* Schedule the send engine. */
         qp->s_flags |= RVT_S_RESP_PENDING;
         if (fecn)
             qp->s_flags |= RVT_S_ECN;
         hfi1_schedule_send(qp);
 
         spin_unlock_irqrestore(&qp->s_lock, flags);
         return;
     }
 
     case OP(COMPARE_SWAP):
     case OP(FETCH_ADD): {
         struct ib_atomic_eth *ateth = &ohdr->u.atomic_eth;
         u64 vaddr = get_ib_ateth_vaddr(ateth);
         bool opfn = opcode == OP(COMPARE_SWAP) &&
             vaddr == HFI1_VERBS_E_ATOMIC_VADDR;
         struct rvt_ack_entry *e;
         atomic64_t *maddr;
         u64 sdata;
         u32 rkey;
         u8 next;
 
         if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_ATOMIC) &&
                  !opfn))
             goto nack_inv;
         next = qp->r_head_ack_queue + 1;
         if (next > rvt_size_atomic(ib_to_rvt(qp->ibqp.device)))
             next = 0;
         spin_lock_irqsave(&qp->s_lock, flags);
         if (unlikely(next == qp->s_acked_ack_queue)) {
             if (!qp->s_ack_queue[next].sent)
                 goto nack_inv_unlck;
             update_ack_queue(qp, next);
         }
         e = &qp->s_ack_queue[qp->r_head_ack_queue];
         release_rdma_sge_mr(e);
         /* Process OPFN special virtual address */
         if (opfn) {
             opfn_conn_response(qp, e, ateth);
             goto ack;
         }
         if (unlikely(vaddr & (sizeof(u64) - 1)))
             goto nack_inv_unlck;
         rkey = be32_to_cpu(ateth->rkey);
         /* Check rkey & NAK */
         if (unlikely(!rvt_rkey_ok(qp, &qp->r_sge.sge, sizeof(u64),
                       vaddr, rkey,
                       IB_ACCESS_REMOTE_ATOMIC)))
             goto nack_acc_unlck;
         /* Perform atomic OP and save result. */
         maddr = (atomic64_t *)qp->r_sge.sge.vaddr;
         sdata = get_ib_ateth_swap(ateth);
         e->atomic_data = (opcode == OP(FETCH_ADD)) ?
             (u64)atomic64_add_return(sdata, maddr) - sdata :
             (u64)cmpxchg((u64 *)qp->r_sge.sge.vaddr,
                       get_ib_ateth_compare(ateth),
                       sdata);
         rvt_put_mr(qp->r_sge.sge.mr);
         qp->r_sge.num_sge = 0;
 ack:
         e->opcode = opcode;
         e->sent = 0;
         e->psn = psn;
         e->lpsn = psn;
         qp->r_msn++;
         qp->r_psn++;
         qp->r_state = opcode;
         qp->r_nak_state = 0;
         qp->r_head_ack_queue = next;
         qpriv->r_tid_alloc = qp->r_head_ack_queue;
 
         /* Schedule the send engine. */
         qp->s_flags |= RVT_S_RESP_PENDING;
         if (fecn)
             qp->s_flags |= RVT_S_ECN;
         hfi1_schedule_send(qp);
 
         spin_unlock_irqrestore(&qp->s_lock, flags);
         return;
     }
 
     default:
         /* NAK unknown opcodes. */
         goto nack_inv;
     }
     qp->r_psn++;
     qp->r_state = opcode;
     qp->r_ack_psn = psn;
     qp->r_nak_state = 0;
     /* Send an ACK if requested or required. */
     if (psn & IB_BTH_REQ_ACK || fecn) {
         if (packet->numpkt == 0 || fecn ||
             qp->r_adefered >= HFI1_PSN_CREDIT) {
             rc_cancel_ack(qp);
             goto send_ack;
         }
         qp->r_adefered++;
         rc_defered_ack(rcd, qp);
     }
     return;
 
 rnr_nak:
     qp->r_nak_state = qp->r_min_rnr_timer | IB_RNR_NAK;
     qp->r_ack_psn = qp->r_psn;
     /* Queue RNR NAK for later */
     rc_defered_ack(rcd, qp);
     return;
 
 nack_op_err:
     rvt_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
     qp->r_nak_state = IB_NAK_REMOTE_OPERATIONAL_ERROR;
     qp->r_ack_psn = qp->r_psn;
     /* Queue NAK for later */
     rc_defered_ack(rcd, qp);
     return;
 
 nack_inv_unlck:
     spin_unlock_irqrestore(&qp->s_lock, flags);
 nack_inv:
     rvt_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
     qp->r_nak_state = IB_NAK_INVALID_REQUEST;
     qp->r_ack_psn = qp->r_psn;
     /* Queue NAK for later */
     rc_defered_ack(rcd, qp);
     return;
 
 nack_acc_unlck:
     spin_unlock_irqrestore(&qp->s_lock, flags);
 nack_acc:
     rvt_rc_error(qp, IB_WC_LOC_PROT_ERR);
     qp->r_nak_state = IB_NAK_REMOTE_ACCESS_ERROR;
     qp->r_ack_psn = qp->r_psn;
 send_ack:
     hfi1_send_rc_ack(packet, fecn);
 }
 
 void hfi1_rc_hdrerr(
     struct hfi1_ctxtdata *rcd,
     struct hfi1_packet *packet,
     struct rvt_qp *qp)
 {
     struct hfi1_ibport *ibp = rcd_to_iport(rcd);
     int diff;
     u32 opcode;
     u32 psn;
 
     if (hfi1_ruc_check_hdr(ibp, packet))
         return;
 
     psn = ib_bth_get_psn(packet->ohdr);
     opcode = ib_bth_get_opcode(packet->ohdr);
 
     /* Only deal with RDMA Writes for now */
     if (opcode < IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST) {
         diff = delta_psn(psn, qp->r_psn);
         if (!qp->r_nak_state && diff >= 0) {
             ibp->rvp.n_rc_seqnak++;
             qp->r_nak_state = IB_NAK_PSN_ERROR;
             /* Use the expected PSN. */
             qp->r_ack_psn = qp->r_psn;
             /*
              * Wait to send the sequence
              * NAK until all packets
              * in the receive queue have
              * been processed.
              * Otherwise, we end up
              * propagating congestion.
              */
             rc_defered_ack(rcd, qp);
         } /* Out of sequence NAK */
     } /* QP Request NAKs */
 }