Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3244 insertions, 0 deletions

diff --git a/drivers/infiniband/hw/hfi1/rc.c b/drivers/infiniband/hw/hfi1/rc.c
new file mode 100644
index 000000000..acd2b273e
--- /dev/null
+++ b/drivers/infiniband/hw/hfi1/rc.c
@@ -0,0 +1,3244 @@
+// 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 */
+}