diff mbox

[for-next,20/24] IB/hfi1: Add TID RDMA WRITE functions

Message ID 20180702152525.16400.47200.stgit@scvm10.sc.intel.com (mailing list archive)
State Changes Requested
Headers show

Commit Message

Dennis Dalessandro July 2, 2018, 3:25 p.m. UTC
From: Kaike Wan <kaike.wan@intel.com>

This patch adds the helper functions for the TID RDMA WRITE protocol.
These routines perform the following functions:
(1) build the TID RDMA WRITE request
(2) receive the TID RDMA WRITE request
(3) build the TID RDMA WRITE response
(4) receive the TID RDMA WRITE response
(5) build the TID RDMA WRITE DATA packet
(6) receive the TID RDMA WRITE DATA packet
(7) build the TID RDMA ACK packet
(8) receive the TID RDMA ACK packet
(9) build the TID RDMA RESYNC packet
(10) receive the TID RDMA RESYNC packet
(11) handle TID resource timer
(12) handle TID retry timer

Many of the routines are called by the RC send engine or the receive
context to handle TID RDMA WRITE request.

Signed-off-by: Mitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Kaike Wan <kaike.wan@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
---
 drivers/infiniband/hw/hfi1/tid_rdma.c | 2160 ++++++++++++++++++++++++++++++++-
 drivers/infiniband/hw/hfi1/verbs.h    |    3 
 2 files changed, 2125 insertions(+), 38 deletions(-)


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diff mbox

Patch

diff --git a/drivers/infiniband/hw/hfi1/tid_rdma.c b/drivers/infiniband/hw/hfi1/tid_rdma.c
index 8887025..9e404e3 100644
--- a/drivers/infiniband/hw/hfi1/tid_rdma.c
+++ b/drivers/infiniband/hw/hfi1/tid_rdma.c
@@ -164,9 +164,12 @@  static u32 mask_generation(u32 a)
  * C - Capcode
  */
 
+#define KDETH_INVALID_PSN  0x80000000
+
 static u32 tid_rdma_flow_wt;
 
 static void hfi1_do_tid_send(struct rvt_qp *qp);
+static void hfi1_tid_write_alloc_resources(struct rvt_qp *qp, bool intr_ctx);
 
 static struct tid_rdma_flow *find_flow_ib(struct tid_rdma_request *req,
 					  u32 psn, u16 *fidx)
@@ -189,6 +192,27 @@  static u32 mask_generation(u32 a)
 	return NULL;
 }
 
+static struct tid_rdma_flow *
+__find_flow_ranged(struct tid_rdma_request *req, u16 head, u16 tail,
+		   u32 psn, u16 *fidx)
+{
+	for ( ; CIRC_CNT(head, tail, req->n_max_flows);
+	      tail = CIRC_NEXT(tail, req->n_max_flows)) {
+		struct tid_rdma_flow *flow = &req->flows[tail];
+		u32 spsn, lpsn;
+
+		spsn = full_flow_psn(flow, flow->flow_state.spsn);
+		lpsn = full_flow_psn(flow, flow->flow_state.lpsn);
+
+		if (cmp_psn(psn, spsn) >= 0 && cmp_psn(psn, lpsn) <= 0) {
+			if (fidx)
+				*fidx = tail;
+			return flow;
+		}
+	}
+	return NULL;
+}
+
 static u8 trdma_pset_order(struct tid_rdma_pageset *s)
 {
 	u8 count = s->count;
@@ -207,16 +231,126 @@  static int hfi1_send_tid_ok(struct rvt_qp *qp)
 		 !(qp->s_flags & HFI1_S_ANY_TID_WAIT_SEND));
 }
 
+/*
+ * @qp: points to rvt_qp context.
+ * @to_seg: desired RNR timeout in segments.
+ * Return: index of the next highest timeout in the ib_hfi1_rnr_table[]
+ */
+static u32 hfi1_compute_tid_rnr_timeout(struct rvt_qp *qp, u32 to_seg)
+{
+	struct hfi1_qp_priv *qpriv = qp->priv;
+	u64 timeout;
+	u32 bytes_per_us;
+	u8 i;
+
+	bytes_per_us = active_egress_rate(qpriv->rcd->ppd) / 8;
+	timeout = (to_seg * TID_RDMA_MAX_SEGMENT_SIZE) / bytes_per_us;
+	/*
+	 * Find the next highest value in the RNR table to the required
+	 * timeout. This gives the responder some padding.
+	 */
+	for (i = 1; i <= IB_AETH_CREDIT_MASK; i++)
+		if (rvt_rnr_tbl_to_usec(i) >= timeout)
+			return i;
+	return 0;
+}
+
+static void hfi1_add_tid_reap_timer(struct rvt_qp *qp)
+{
+	struct hfi1_qp_priv *qpriv = qp->priv;
+
+	lockdep_assert_held(&qp->s_lock);
+	if (!(qpriv->s_flags & HFI1_R_TID_RSC_TIMER)) {
+		qpriv->s_flags |= HFI1_R_TID_RSC_TIMER;
+		qpriv->s_tid_timer.expires = jiffies +
+			qpriv->tid_timer_timeout_jiffies;
+		add_timer(&qpriv->s_tid_timer);
+	}
+}
+
+static void hfi1_mod_tid_reap_timer(struct rvt_qp *qp)
+{
+	struct hfi1_qp_priv *qpriv = qp->priv;
+
+	lockdep_assert_held(&qp->s_lock);
+	qpriv->s_flags |= HFI1_R_TID_RSC_TIMER;
+	mod_timer(&qpriv->s_tid_timer, jiffies +
+		  qpriv->tid_timer_timeout_jiffies);
+}
+
+static int hfi1_stop_tid_reap_timer(struct rvt_qp *qp)
+{
+	struct hfi1_qp_priv *qpriv = qp->priv;
+	int rval = 0;
+
+	lockdep_assert_held(&qp->s_lock);
+	if (qpriv->s_flags & HFI1_R_TID_RSC_TIMER) {
+		rval = del_timer(&qpriv->s_tid_timer);
+		qpriv->s_flags &= ~HFI1_R_TID_RSC_TIMER;
+	}
+	return rval;
+}
+
 void hfi1_del_tid_reap_timer(struct rvt_qp *qp)
 {
+	struct hfi1_qp_priv *qpriv = qp->priv;
+
+	del_timer_sync(&qpriv->s_tid_timer);
+	qpriv->s_flags &= ~HFI1_R_TID_RSC_TIMER;
 }
 
 void hfi1_add_tid_retry_timer(struct rvt_qp *qp)
 {
+	struct hfi1_qp_priv *priv = qp->priv;
+	struct ib_qp *ibqp = &qp->ibqp;
+	struct rvt_dev_info *rdi = ib_to_rvt(ibqp->device);
+
+	lockdep_assert_held(&qp->s_lock);
+	if (!(priv->s_flags & HFI1_S_TID_RETRY_TIMER)) {
+		priv->s_flags |= HFI1_S_TID_RETRY_TIMER;
+		priv->s_tid_retry_timer.expires = jiffies +
+			priv->tid_retry_timeout_jiffies + rdi->busy_jiffies;
+		add_timer(&priv->s_tid_retry_timer);
+	}
+}
+
+static void hfi1_mod_tid_retry_timer(struct rvt_qp *qp)
+{
+	struct hfi1_qp_priv *priv = qp->priv;
+	struct ib_qp *ibqp = &qp->ibqp;
+	struct rvt_dev_info *rdi = ib_to_rvt(ibqp->device);
+
+	lockdep_assert_held(&qp->s_lock);
+	priv->s_flags |= HFI1_S_TID_RETRY_TIMER;
+	mod_timer(&priv->s_tid_retry_timer, jiffies +
+		  priv->tid_retry_timeout_jiffies + rdi->busy_jiffies);
+}
+
+static int hfi1_stop_tid_retry_timer(struct rvt_qp *qp)
+{
+	struct hfi1_qp_priv *priv = qp->priv;
+	int rval = 0;
+
+	lockdep_assert_held(&qp->s_lock);
+	if (priv->s_flags & HFI1_S_TID_RETRY_TIMER) {
+		rval = del_timer(&priv->s_tid_retry_timer);
+		priv->s_flags &= ~HFI1_S_TID_RETRY_TIMER;
+	}
+	return rval;
 }
 
 void hfi1_del_tid_retry_timer(struct rvt_qp *qp)
 {
+	struct hfi1_qp_priv *priv = qp->priv;
+
+	del_timer_sync(&priv->s_tid_retry_timer);
+	priv->s_flags &= ~HFI1_S_TID_RETRY_TIMER;
+}
+
+static bool hfi1_tid_rdma_is_resync_psn(u32 psn)
+{
+	return (bool)((psn & HFI1_KDETH_BTH_SEQ_MASK) ==
+		      HFI1_KDETH_BTH_SEQ_MASK);
 }
 
 static u64 tid_rdma_opfn_encode(struct tid_rdma_params *p)
@@ -1698,6 +1832,8 @@  static int tid_rdma_rcv_error(struct hfi1_packet *packet,
 {
 	struct hfi1_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
 	struct hfi1_ctxtdata *rcd = ((struct hfi1_qp_priv *)qp->priv)->rcd;
+	struct hfi1_ibdev *dev = to_idev(qp->ibqp.device);
+	struct hfi1_qp_priv *qpriv = qp->priv;
 	struct rvt_ack_entry *e;
 	struct tid_rdma_request *req;
 	unsigned long flags;
@@ -1726,6 +1862,113 @@  static int tid_rdma_rcv_error(struct hfi1_packet *packet,
 	req = ack_to_tid_req(e);
 	req->r_flow_psn = psn;
 	if (e->opcode == TID_OP(WRITE_REQ)) {
+		struct flow_state *fstate;
+		bool schedule = false;
+		u8 i;
+
+		if (req->state == TID_REQUEST_RESEND) {
+			req->state = TID_REQUEST_RESEND_ACTIVE;
+		} else if (req->state == TID_REQUEST_INIT_RESEND) {
+			req->state = TID_REQUEST_INIT;
+			schedule = true;
+		}
+
+		/*
+		 * True if the request is already scheduled (between
+		 * qp->s_tail_ack_queue and qp->r_head_ack_queue).
+		 * Also, don't change requests, which are at the SYNC
+		 * point and haven't generated any responses yet.
+		 * There is nothing to retransmit for them yet.
+		 */
+		if (old_req || req->state == TID_REQUEST_INIT ||
+		    (req->state == TID_REQUEST_SYNC && !req->cur_seg)) {
+			for (i = prev + 1; ; i++) {
+				if (i > rvt_size_atomic(&dev->rdi))
+					i = 0;
+				if (i == qp->r_head_ack_queue)
+					break;
+				e = &qp->s_ack_queue[i];
+				req = ack_to_tid_req(e);
+				if (e->opcode == TID_OP(WRITE_REQ) &&
+				    req->state == TID_REQUEST_INIT)
+					req->state = TID_REQUEST_INIT_RESEND;
+			}
+			/*
+			 * If the state of the request has been changed,
+			 * the first leg needs to get scheduled in order to
+			 * pick up the change. Otherwise, normal response
+			 * processing should take care of it.
+			 */
+			if (!schedule)
+				goto unlock;
+		}
+
+		/*
+		 * If there is no more allocated segment, just schedule the qp
+		 * without changing any state.
+		 */
+		if (req->clear_tail == req->setup_head)
+			goto schedule;
+		/*
+		 * If this request has sent responses for segments, which have
+		 * not received data yet (flow_idx != clear_tail), the flow_idx
+		 * pointer needs to be adjusted so the same responses can be
+		 * re-sent.
+		 */
+		if (CIRC_CNT(req->flow_idx, req->clear_tail,
+			     req->n_max_flows)) {
+			fstate = &req->flows[req->clear_tail].flow_state;
+			qpriv->pending_tid_w_segs -=
+				CIRC_CNT(req->flow_idx, req->clear_tail,
+					 req->n_max_flows);
+			req->flow_idx =
+				CIRC_ADD(req->clear_tail,
+					 delta_psn(psn, fstate->resp_ib_psn),
+					 req->n_max_flows);
+			qpriv->pending_tid_w_segs +=
+				delta_psn(psn, fstate->resp_ib_psn);
+			/*
+			 * When flow_idx == setup_head, we've gotten a duplicate
+			 * request for a segment, which has not been allocated
+			 * yet. In that case, don't adjust this request.
+			 * However, we still want to go through the loop below
+			 * to adjust all subsequent requests.
+			 */
+			if (CIRC_CNT(req->setup_head, req->flow_idx,
+				     req->n_max_flows)) {
+				req->cur_seg = delta_psn(psn, e->psn);
+				req->state = TID_REQUEST_RESEND_ACTIVE;
+			}
+		}
+
+		for (i = prev + 1; ; i++) {
+			/*
+			 * Look at everything up to and including
+			 * s_tail_ack_queue
+			 */
+			if (i > rvt_size_atomic(&dev->rdi))
+				i = 0;
+			if (i == qp->r_head_ack_queue)
+				break;
+			e = &qp->s_ack_queue[i];
+			req = ack_to_tid_req(e);
+			if (e->opcode != TID_OP(WRITE_REQ) ||
+			    req->cur_seg == req->comp_seg ||
+			    req->state == TID_REQUEST_INIT ||
+			    req->state == TID_REQUEST_INIT_RESEND) {
+				if (req->state == TID_REQUEST_INIT)
+					req->state = TID_REQUEST_INIT_RESEND;
+				continue;
+			}
+			qpriv->pending_tid_w_segs -=
+				CIRC_CNT(req->flow_idx,
+					 req->clear_tail,
+					 req->n_max_flows);
+			req->flow_idx = req->clear_tail;
+			req->state = TID_REQUEST_RESEND;
+			req->cur_seg = req->comp_seg;
+		}
+		qpriv->s_flags &= ~HFI1_R_TID_WAIT_INTERLCK;
 	} else {
 		struct ib_reth *reth;
 		u32 offset;
@@ -1775,26 +2018,12 @@  static int tid_rdma_rcv_error(struct hfi1_packet *packet,
 			goto unlock;
 
 		/*
-		 * If all the response packets for the current request have
-		 * been sent out and this request is complete (old_request
-		 * == false) and the TID flow may be unusable (the
-		 * req->clear_tail is advanced). However, when an earlier
-		 * request is received, this request will not be complete any
-		 * more (qp->s_tail_ack_queue is moved back, see below).
-		 * Consequently, we need to update the TID flow info everytime
-		 * a duplicate request is received.
-		 */
-		bth0 = be32_to_cpu(ohdr->bth[0]);
-		if (tid_rdma_rcv_read_request(qp, e, packet, ohdr, bth0, psn,
-					      vaddr, len))
-			goto unlock;
-
-		/*
 		 * True if the request is already scheduled (between
 		 * qp->s_tail_ack_queue and qp->r_head_ack_queue);
 		 */
 		if (old_req)
 			goto unlock;
+
 	}
 	/* Re-process old requests.*/
 	if (qp->s_acked_ack_queue == qp->s_tail_ack_queue)
@@ -1807,6 +2036,18 @@  static int tid_rdma_rcv_error(struct hfi1_packet *packet,
 	 * wrong memory region.
 	 */
 	qp->s_ack_state = OP(ACKNOWLEDGE);
+schedule:
+	/*
+	 * It's possible to receive a retry psn that is earlier than an RNRNAK
+	 * psn. In this case, the rnrnak state should be cleared.
+	 */
+	if (qpriv->rnr_nak_state) {
+		qp->s_nak_state = 0;
+		qpriv->rnr_nak_state = TID_RNR_NAK_INIT;
+		qp->r_psn = e->lpsn + 1;
+		hfi1_tid_write_alloc_resources(qp, true);
+	}
+
 	qp->r_state = e->opcode;
 	qp->r_nak_state = 0;
 	qp->s_flags |= RVT_S_RESP_PENDING;
@@ -1817,16 +2058,678 @@  static int tid_rdma_rcv_error(struct hfi1_packet *packet,
 	return 1;
 }
 
+static u32 position_in_queue(struct hfi1_qp_priv *qpriv,
+			     struct tid_queue *queue)
+{
+	return qpriv->tid_enqueue - queue->dequeue;
+}
+
+/**
+ * Central place for resource allocation at TID write responder, is called from
+ * write_req and write_data interrupt handlers as well as the send thread when a
+ * queued QP is scheduled for resource allocation.
+ *
+ * Iterates over (a) segments of a request and then (b) queued requests
+ * themselves to allocate resources for upto local->max_write segments across
+ * multiple requests. Stop allocating when we hit a sync point, resume
+ * allocating after data packets at sync point have been received.
+ *
+ * Resource allocation and sending of responses is decoupled. The
+ * request/segment which are being allocated and sent are as follows.
+ * Resources are allocated for:
+ *     [request: qpriv->r_tid_alloc, segment: req->alloc_seg]
+ * The send thread sends:
+ *     [request: qp->s_tail_ack_queue, segment:req->cur_seg]
+ */
+static void hfi1_tid_write_alloc_resources(struct rvt_qp *qp, bool intr_ctx)
+{
+	struct tid_rdma_request *req;
+	struct hfi1_qp_priv *qpriv = qp->priv;
+	struct hfi1_ctxtdata *rcd = qpriv->rcd;
+	struct tid_rdma_params *local = &qpriv->tid_rdma.local;
+	struct rvt_ack_entry *e;
+	u32 npkts, to_seg;
+	bool last;
+	int ret = 0;
+
+	lockdep_assert_held(&qp->s_lock);
+
+	while (1) {
+		/*
+		 * Don't allocate more segments if a RNR NAK has already been
+		 * scheduled to avoid messing up qp->r_psn: the RNR NAK will
+		 * be sent only when all allocated segments have been sent.
+		 * However, if more segments are allocated before that, TID RDMA
+		 * WRITE RESP packets will be sent out for these new segments
+		 * before the RNR NAK packet. When the requester receives the
+		 * RNR NAK packet, it will restart with qp->s_last_psn + 1,
+		 * which does not match qp->r_psn and will be dropped.
+		 * Consequently, the requester will exhaust its retries and
+		 * put the qp into error state.
+		 */
+		if (qpriv->rnr_nak_state == TID_RNR_NAK_SEND)
+			break;
+
+		/* No requests left to process */
+		if (qpriv->r_tid_alloc == qpriv->r_tid_head) {
+			/* If all data has been received, clear the flow */
+			if (qpriv->flow_state.index < RXE_NUM_TID_FLOWS &&
+			    !qpriv->alloc_w_segs)
+				hfi1_kern_clear_hw_flow(rcd, qp);
+			break;
+		}
+
+		e = &qp->s_ack_queue[qpriv->r_tid_alloc];
+		if (e->opcode != TID_OP(WRITE_REQ))
+			goto next_req;
+		req = ack_to_tid_req(e);
+		/* Finished allocating for all segments of this request */
+		if (req->alloc_seg >= req->total_segs)
+			goto next_req;
+
+		/* Can allocate only a maximum of local->max_write for a QP */
+		if (qpriv->alloc_w_segs >= local->max_write)
+			break;
+
+		/* Don't allocate at a sync point with data packets pending */
+		if (qpriv->sync_pt && qpriv->alloc_w_segs)
+			break;
+
+		/* All data received at the sync point, continue */
+		if (qpriv->sync_pt && !qpriv->alloc_w_segs) {
+			hfi1_kern_clear_hw_flow(rcd, qp);
+			qpriv->sync_pt = false;
+			if (qpriv->s_flags & HFI1_R_TID_SW_PSN)
+				qpriv->s_flags &= ~HFI1_R_TID_SW_PSN;
+		}
+
+		/* Allocate flow if we don't have one */
+		if (qpriv->flow_state.index >= RXE_NUM_TID_FLOWS) {
+			ret = hfi1_kern_setup_hw_flow(qpriv->rcd, qp);
+			if (ret) {
+				to_seg = tid_rdma_flow_wt *
+					position_in_queue(qpriv,
+							  &rcd->flow_queue);
+				break;
+			}
+		}
+
+		npkts = rvt_div_round_up_mtu(qp, req->seg_len);
+
+		/*
+		 * We are at a sync point if we run out of KDETH PSN space.
+		 * Last PSN of every generation is reserved for RESYNC.
+		 */
+		if (qpriv->flow_state.psn + npkts > MAX_TID_FLOW_PSN - 1) {
+			qpriv->sync_pt = true;
+			break;
+		}
+
+		/*
+		 * If overtaking req->acked_tail, send an RNR NAK. Because the
+		 * QP is not queued in this case, and the issue can only be
+		 * caused due a delay in scheduling the second leg which we
+		 * cannot estimate, we use a rather arbitrary RNR timeout of
+		 * (req->n_max_flows / 2) segments
+		 */
+		if (!CIRC_SPACE(req->setup_head, req->acked_tail,
+				req->n_max_flows)) {
+			ret = -EAGAIN;
+			to_seg = req->n_max_flows >> 1;
+			qpriv->s_flags |= RVT_S_ACK_PENDING;
+			hfi1_schedule_tid_send(qp);
+			break;
+		}
+
+		/* Try to allocate rcv array / TID entries */
+		ret = hfi1_kern_exp_rcv_setup(req, &req->ss, &last);
+		if (ret == -EAGAIN)
+			to_seg = position_in_queue(qpriv, &rcd->rarr_queue);
+		if (ret)
+			break;
+
+		qpriv->alloc_w_segs++;
+		req->alloc_seg++;
+		continue;
+next_req:
+		/* Begin processing the next request */
+		if (++qpriv->r_tid_alloc >
+		    rvt_size_atomic(ib_to_rvt(qp->ibqp.device)))
+			qpriv->r_tid_alloc = 0;
+	}
+
+	/*
+	 * Schedule an RNR NAK to be sent if (a) flow or rcv array allocation
+	 * has failed (b) we are called from the rcv handler interrupt context
+	 * (c) an RNR NAK has not already been scheduled
+	 */
+	if (ret == -EAGAIN && intr_ctx && !qp->r_nak_state)
+		goto send_rnr_nak;
+
+	return;
+
+send_rnr_nak:
+	/*
+	 * NO_RNR_NAK turns off sending RNR NAK's. RNR NAK's will not be sent
+	 * but everything else will work as expected. The remote QP might time
+	 * out and resend the request if it doesn't receive a response. The
+	 * resent request will be discarded as duplicate. This works as long as
+	 * the remote QP does not run out of retries
+	 */
+#ifdef NO_RNR_NAK
+	return;
+#endif
+	lockdep_assert_held(&qp->r_lock);
+
+	/* Set r_nak_state to prevent unrelated events from generating NAK's */
+	qp->r_nak_state = hfi1_compute_tid_rnr_timeout(qp, to_seg) | IB_RNR_NAK;
+
+	/* Pull back r_psn to the segment being RNR NAK'd */
+	qp->r_psn = e->psn + req->alloc_seg;
+	qp->r_ack_psn = qp->r_psn;
+	/*
+	 * Pull back r_head_ack_queue to the ack entry following the request
+	 * being RNR NAK'd. This allows resources to be allocated to the request
+	 * if the queued QP is scheduled.
+	 */
+	qp->r_head_ack_queue = qpriv->r_tid_alloc + 1;
+	if (qp->r_head_ack_queue > rvt_size_atomic(ib_to_rvt(qp->ibqp.device)))
+		qp->r_head_ack_queue = 0;
+	qpriv->r_tid_head = qp->r_head_ack_queue;
+	/*
+	 * These send side fields are used in make_rc_ack(). They are set in
+	 * hfi1_send_rc_ack() but must be set here before dropping qp->s_lock
+	 * for consistency
+	 */
+	qp->s_nak_state = qp->r_nak_state;
+	qp->s_ack_psn = qp->r_ack_psn;
+	/*
+	 * Clear the ACK PENDING flag to prevent unwanted ACK because we
+	 * have modified qp->s_ack_psn here.
+	 */
+	qp->s_flags &= ~(RVT_S_ACK_PENDING);
+	/*
+	 * qpriv->rnr_nak_state is used to determine when the scheduled RNR NAK
+	 * has actually been sent. qp->s_flags RVT_S_ACK_PENDING bit cannot be
+	 * used for this because qp->s_lock is dropped before calling
+	 * hfi1_send_rc_ack() leading to inconsistency between the receive
+	 * interrupt handlers and the send thread in make_rc_ack()
+	 */
+	qpriv->rnr_nak_state = TID_RNR_NAK_SEND;
+
+	/*
+	 * Schedule RNR NAK to be sent. RNR NAK's are scheduled from the receive
+	 * interrupt handlers but will be sent from the send engine behind any
+	 * previous responses that may have been scheduled
+	 */
+	rc_defered_ack(rcd, qp);
+}
+
 void hfi1_rc_rcv_tid_rdma_write_req(struct hfi1_packet *packet)
 {
+	/* HANDLER FOR TID RDMA WRITE REQUEST packet (Responder side)*/
+
+	/*
+	 * 1. Verify TID RDMA WRITE REQ as per IB_OPCODE_RC_RDMA_WRITE_FIRST
+	 *    (see hfi1_rc_rcv())
+	 *     - Don't allow 0-length requests.
+	 * 2. Put TID RDMA WRITE REQ into the response queueu (s_ack_queue)
+	 *     - Setup struct tid_rdma_req with request info
+	 *     - Prepare struct tid_rdma_flow array?
+	 * 3. Set the qp->s_ack_state as state diagram in design doc.
+	 * 4. Set RVT_S_RESP_PENDING in s_flags.
+	 * 5. Kick the send engine (hfi1_schedule_send())
+	 */
+	struct hfi1_ctxtdata *rcd = packet->rcd;
+	struct rvt_qp *qp = packet->qp;
+	struct hfi1_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
+	struct ib_other_headers *ohdr = packet->ohdr;
+	struct rvt_ack_entry *e;
+	unsigned long flags;
+	struct ib_reth *reth;
+	struct hfi1_qp_priv *qpriv = qp->priv;
+	struct tid_rdma_request *req;
+	u32 bth0, psn, len, rkey, num_segs;
+	bool is_fecn;
+	u8 next;
+	u64 vaddr;
+	int diff;
+
+	bth0 = be32_to_cpu(ohdr->bth[0]);
+	if (hfi1_ruc_check_hdr(ibp, packet))
+		return;
+
+	is_fecn = process_ecn(qp, packet, false);
+	psn = mask_psn(be32_to_cpu(ohdr->bth[2]));
+
+	if (qp->state == IB_QPS_RTR && !(qp->r_flags & RVT_R_COMM_EST))
+		rvt_comm_est(qp);
+
+	if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_WRITE)))
+		goto nack_inv;
+
+	reth = &ohdr->u.tid_rdma.w_req.reth;
+	vaddr = be64_to_cpu(reth->vaddr);
+	len = be32_to_cpu(reth->length);
+
+	num_segs = DIV_ROUND_UP(len, qpriv->tid_rdma.local.max_len);
+	diff = delta_psn(psn, qp->r_psn);
+	if (unlikely(diff)) {
+		if (tid_rdma_rcv_error(packet, ohdr, qp, psn, diff))
+			return;
+		goto send_ack;
+	}
+
+	/*
+	 * The resent request which was previously RNR NAK'd is inserted at the
+	 * location of the original request, which is one entry behind
+	 * r_head_ack_queue
+	 */
+	if (qpriv->rnr_nak_state)
+		qp->r_head_ack_queue = qp->r_head_ack_queue ?
+			qp->r_head_ack_queue - 1 :
+			rvt_size_atomic(ib_to_rvt(qp->ibqp.device));
+
+	/* We've verified the request, insert it into the ack queue. */
+	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_unlock;
+		update_ack_queue(qp, next);
+	}
+	e = &qp->s_ack_queue[qp->r_head_ack_queue];
+	req = ack_to_tid_req(e);
+
+	/* Bring previously RNR NAK'd request back to life */
+	if (qpriv->rnr_nak_state) {
+		qp->r_nak_state = 0;
+		qp->s_nak_state = 0;
+		qpriv->rnr_nak_state = TID_RNR_NAK_INIT;
+		qp->r_psn = e->lpsn + 1;
+		req->state = TID_REQUEST_INIT;
+		goto update_head;
+	}
+
+	if (e->rdma_sge.mr) {
+		rvt_put_mr(e->rdma_sge.mr);
+		e->rdma_sge.mr = NULL;
+	}
+
+	/* The length needs to be in multiples of PAGE_SIZE */
+	if (!len || len & ~PAGE_MASK)
+		goto nack_inv_unlock;
+
+	rkey = be32_to_cpu(reth->rkey);
+	qp->r_len = len;
+
+	if (e->opcode == TID_OP(WRITE_REQ) &&
+	    (req->setup_head != req->clear_tail ||
+	     req->clear_tail != req->acked_tail))
+		goto nack_inv_unlock;
+
+	if (unlikely(!rvt_rkey_ok(qp, &e->rdma_sge, qp->r_len, vaddr,
+				  rkey, IB_ACCESS_REMOTE_WRITE)))
+		goto nack_acc;
+
+	qp->r_psn += num_segs - 1;
+
+	e->opcode = (bth0 >> 24) & 0xff;
+	e->psn = psn;
+	e->lpsn = qp->r_psn;
+	e->sent = 0;
+
+	req->n_flows = min_t(u16, num_segs, qpriv->tid_rdma.local.max_write);
+	req->state = TID_REQUEST_INIT;
+	req->cur_seg = 0;
+	req->comp_seg = 0;
+	req->ack_seg = 0;
+	req->alloc_seg = 0;
+	req->isge = 0;
+	req->seg_len = qpriv->tid_rdma.local.max_len;
+	req->total_len = len;
+	req->total_segs = num_segs;
+	req->r_flow_psn = e->psn;
+	req->ss.sge = e->rdma_sge;
+	req->ss.num_sge = 1;
+
+	req->flow_idx = req->setup_head;
+	req->clear_tail = req->setup_head;
+	req->acked_tail = req->setup_head;
+
+	qp->r_state = e->opcode;
+	qp->r_nak_state = 0;
+	/*
+	 * 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++;
+
+	if (qpriv->r_tid_tail == HFI1_QP_WQE_INVALID) {
+		qpriv->r_tid_tail = qp->r_head_ack_queue;
+	} else if (qpriv->r_tid_tail == qpriv->r_tid_head) {
+		struct tid_rdma_request *ptr;
+
+		e = &qp->s_ack_queue[qpriv->r_tid_tail];
+		ptr = ack_to_tid_req(e);
+
+		if (e->opcode != TID_OP(WRITE_REQ) ||
+		    ptr->comp_seg == ptr->total_segs) {
+			if (qpriv->r_tid_tail == qpriv->r_tid_ack)
+				qpriv->r_tid_ack = qp->r_head_ack_queue;
+			qpriv->r_tid_tail = qp->r_head_ack_queue;
+		}
+	}
+update_head:
+	qp->r_head_ack_queue = next;
+	qpriv->r_tid_head = qp->r_head_ack_queue;
+
+	hfi1_tid_write_alloc_resources(qp, true);
+
+	/* Schedule the send tasklet. */
+	qp->s_flags |= RVT_S_RESP_PENDING;
+	hfi1_schedule_send(qp);
+
+	spin_unlock_irqrestore(&qp->s_lock, flags);
+	if (is_fecn)
+		goto send_ack;
+	return;
+
+nack_inv_unlock:
+	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:
+	spin_unlock_irqrestore(&qp->s_lock, flags);
+	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, is_fecn);
 }
 
 void hfi1_rc_rcv_tid_rdma_write_data(struct hfi1_packet *packet)
 {
+	struct rvt_qp *qp = packet->qp;
+	struct hfi1_qp_priv *priv = qp->priv;
+	struct hfi1_ctxtdata *rcd = priv->rcd;
+	struct ib_other_headers *ohdr = packet->ohdr;
+	struct rvt_ack_entry *e;
+	struct tid_rdma_request *req;
+	struct tid_rdma_flow *flow;
+	struct hfi1_ibdev *dev = to_idev(qp->ibqp.device);
+	unsigned long flags;
+	u32 psn, next;
+	u8 opcode;
+
+	psn = mask_psn(be32_to_cpu(ohdr->bth[2]));
+	opcode = (be32_to_cpu(ohdr->bth[0]) >> 24) & 0xff;
+
+	/*
+	 * All error handling should be done by now. If we are here, the packet
+	 * is either good or been accepted by the error handler.
+	 */
+	spin_lock_irqsave(&qp->s_lock, flags);
+	e = &qp->s_ack_queue[priv->r_tid_tail];
+	req = ack_to_tid_req(e);
+	flow = &req->flows[req->clear_tail];
+	if (cmp_psn(psn, full_flow_psn(flow, flow->flow_state.lpsn))) {
+		if (cmp_psn(psn, flow->flow_state.r_next_psn))
+			goto send_nak;
+		flow->flow_state.r_next_psn++;
+		goto exit;
+	}
+	flow->flow_state.r_next_psn = mask_psn(psn + 1);
+	hfi1_kern_exp_rcv_clear(req);
+	priv->alloc_w_segs--;
+	rcd->flows[flow->idx].psn = psn & HFI1_KDETH_BTH_SEQ_MASK;
+	req->comp_seg++;
+	priv->s_nak_state = 0;
+
+	/*
+	 * Release the flow if one of the following conditions has been met:
+	 *  - The request has reached a sync point AND all outstanding
+	 *    segments have been completed, or
+	 *  - The entire request is complete and there are no more requests
+	 *    (of any kind) in the queue.
+	 */
+
+	if (priv->r_tid_ack == HFI1_QP_WQE_INVALID)
+		priv->r_tid_ack = priv->r_tid_tail;
+
+	if (opcode == TID_OP(WRITE_DATA_LAST)) {
+		for (next = priv->r_tid_tail + 1; ; next++) {
+			if (next > rvt_size_atomic(&dev->rdi))
+				next = 0;
+			if (next == priv->r_tid_head)
+				break;
+			e = &qp->s_ack_queue[next];
+			if (e->opcode == TID_OP(WRITE_REQ))
+				break;
+		}
+		priv->r_tid_tail = next;
+		if (++qp->s_acked_ack_queue > rvt_size_atomic(&dev->rdi))
+			qp->s_acked_ack_queue = 0;
+	}
+
+	hfi1_tid_write_alloc_resources(qp, true);
+
+	/*
+	 * If we need to generate more responses, schedule the
+	 * send engine.
+	 */
+	if (req->cur_seg < req->total_segs ||
+	    qp->s_tail_ack_queue != qp->r_head_ack_queue) {
+		qp->s_flags |= RVT_S_RESP_PENDING;
+		hfi1_schedule_send(qp);
+	}
+
+	priv->pending_tid_w_segs--;
+	if (priv->s_flags & HFI1_R_TID_RSC_TIMER) {
+		if (priv->pending_tid_w_segs)
+			hfi1_mod_tid_reap_timer(req->qp);
+		else
+			hfi1_stop_tid_reap_timer(req->qp);
+	}
+
+done:
+	priv->s_flags |= RVT_S_ACK_PENDING;
+	hfi1_schedule_tid_send(qp);
+exit:
+	priv->r_next_psn_kdeth = flow->flow_state.r_next_psn;
+	spin_unlock_irqrestore(&qp->s_lock, flags);
+	return;
+
+send_nak:
+	if (!priv->s_nak_state) {
+		priv->s_nak_state = IB_NAK_PSN_ERROR;
+		priv->s_nak_psn = flow->flow_state.r_next_psn;
+		priv->s_flags |= RVT_S_ACK_PENDING;
+		if (priv->r_tid_ack == HFI1_QP_WQE_INVALID)
+			priv->r_tid_ack = priv->r_tid_tail;
+		hfi1_schedule_tid_send(qp);
+	}
+	goto done;
 }
 
 void hfi1_rc_rcv_tid_rdma_write_resp(struct hfi1_packet *packet)
 {
+	/* HANDLER FOR TID RDMA WRITE RESPONSE packet (Requestor side */
+
+	/*
+	 * 1. Find matching SWQE
+	 * 2. Check that TIDENTRY array has enough space for a complete
+	 *    segment. If not, put QP in error state.
+	 * 3. Save response data in struct tid_rdma_req and struct tid_rdma_flow
+	 * 4. Remove HFI1_S_WAIT_TID_RESP from s_flags.
+	 * 5. Set qp->s_state as per state diagram in design doc
+	 * 6. Kick the send engine (hfi1_schedule_send())
+	 */
+	struct ib_other_headers *ohdr = packet->ohdr;
+	struct rvt_qp *qp = packet->qp;
+	struct hfi1_qp_priv *qpriv = qp->priv;
+	struct hfi1_ctxtdata *rcd = packet->rcd;
+	struct rvt_swqe *wqe;
+	struct tid_rdma_request *req;
+	struct tid_rdma_flow *flow;
+	enum ib_wc_status status;
+	u32 opcode, aeth, psn, flow_psn, i, tidlen = 0, pktlen;
+	bool is_fecn;
+	unsigned long flags;
+
+	is_fecn = process_ecn(qp, packet, false);
+	psn = mask_psn(be32_to_cpu(ohdr->bth[2]));
+	aeth = be32_to_cpu(ohdr->u.tid_rdma.w_rsp.aeth);
+	opcode = (be32_to_cpu(ohdr->bth[0]) >> 24) & 0xff;
+
+	spin_lock_irqsave(&qp->s_lock, flags);
+
+	/* Ignore invalid responses */
+	if (cmp_psn(psn, qp->s_next_psn) >= 0)
+		goto ack_done;
+
+	/* Ignore duplicate responses. */
+	/* XXX Check with TID RDMA spec if this is possible */
+	if (unlikely(cmp_psn(psn, qp->s_last_psn) <= 0))
+		goto ack_done;
+
+	if (unlikely(qp->s_acked == qp->s_tail))
+		goto ack_done;
+
+	/*
+	 * If we are waiting for a particular packet sequence number
+	 * due to a request being resent, check for it. Otherwise,
+	 * ensure that we haven't missed anything.
+	 */
+	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;
+	}
+
+	wqe = rvt_get_swqe_ptr(qp, qpriv->s_tid_cur);
+	if (unlikely(wqe->wr.opcode != IB_WR_TID_RDMA_WRITE))
+		goto ack_op_err;
+
+	req = wqe_to_tid_req(wqe);
+	/*
+	 * If we've lost ACKs and our acked_tail pointer is too far
+	 * behind, don't overwrite segments. Just drop the packet and
+	 * let the reliability protocol take care of it.
+	 */
+	if (!CIRC_SPACE(req->setup_head, req->acked_tail,
+			req->n_max_flows))
+		goto ack_done;
+
+	/*
+	 * The call to do_rc_ack() should be last in the chain of
+	 * packet checks because it will end up updating the QP state.
+	 * Therefore, anything that would prevent the packet from
+	 * being accepted as a successful response should be prior
+	 * to it.
+	 */
+	if (!do_rc_ack(qp, aeth, psn, opcode, 0, rcd))
+		goto ack_done;
+
+	trace_hfi1_ack(qp, psn);
+
+	flow = &req->flows[req->setup_head];
+	flow->req = req;
+	flow->pkt = 0;
+	flow->tid_idx = 0;
+	flow->sent = 0;
+	flow->resync_npkts = 0;
+	flow->tid_qpn = be32_to_cpu(ohdr->u.tid_rdma.w_rsp.tid_flow_qp);
+	flow->idx = (flow->tid_qpn >> TID_RDMA_DESTQP_FLOW_SHIFT) &
+		TID_RDMA_DESTQP_FLOW_MASK;
+	flow_psn = mask_psn(be32_to_cpu(ohdr->u.tid_rdma.w_rsp.tid_flow_psn));
+	flow->flow_state.generation = flow_psn >> HFI1_KDETH_BTH_SEQ_SHIFT;
+	flow->flow_state.spsn = flow_psn & HFI1_KDETH_BTH_SEQ_MASK;
+	flow->flow_state.resp_ib_psn = psn;
+	flow->length = min_t(u32, req->seg_len,
+			     (wqe->length - (req->comp_seg * req->seg_len)));
+
+	flow->npkts = rvt_div_round_up_mtu(qp, flow->length);
+	flow->flow_state.lpsn = flow->flow_state.spsn +
+		flow->npkts - 1;
+	/* payload length = packet length - (header length + ICRC length) */
+	pktlen = packet->tlen - (packet->hlen + 4);
+	memcpy(flow->fstate->tid_entry, packet->ebuf, pktlen);
+	flow->tidcnt = pktlen / sizeof(*flow->fstate->tid_entry);
+
+	req->comp_seg++;
+	/*
+	 * Walk the TID_ENTRY list to make sure we have enough space for a
+	 * complete segment.
+	 */
+	for (i = 0; i < flow->tidcnt; i++) {
+		if (!EXP_TID_GET(flow->fstate->tid_entry[i], LEN)) {
+			status = IB_WC_LOC_LEN_ERR;
+			goto ack_err;
+		}
+		tidlen += EXP_TID_GET(flow->fstate->tid_entry[i], LEN);
+	}
+	if (tidlen * PAGE_SIZE < flow->length) {
+		status = IB_WC_LOC_LEN_ERR;
+		goto ack_err;
+	}
+
+	/*
+	 * If this is the first response for this request, set the initial
+	 * flow index to the current flow.
+	 */
+	if (!cmp_psn(psn, wqe->psn)) {
+		req->r_last_acked = mask_psn(wqe->psn - 1);
+		/* Set acked flow index to head index */
+		req->acked_tail = req->setup_head;
+	}
+
+	/* advance circular buffer head */
+	req->setup_head = CIRC_NEXT(req->setup_head, req->n_max_flows);
+	req->state = TID_REQUEST_ACTIVE;
+
+	/*
+	 * If all responses for this TID RDMA WRITE request have been received
+	 * advance the pointer to the next one.
+	 * Since TID RDMA requests could be mixed in with regular IB requests,
+	 * they might not appear sequentially in the queue. Therefore, the
+	 * next request needs to be "found".
+	 */
+	if (qpriv->s_tid_cur != qpriv->s_tid_head &&
+	    req->comp_seg == req->total_segs) {
+		for (i = qpriv->s_tid_cur + 1; ; i++) {
+			if (i == qp->s_size)
+				i = 0;
+			wqe = rvt_get_swqe_ptr(qp, i);
+			if (i == qpriv->s_tid_head)
+				break;
+			if (wqe->wr.opcode == IB_WR_TID_RDMA_WRITE)
+				break;
+		}
+		qpriv->s_tid_cur = i;
+	}
+	qp->s_flags &= ~HFI1_S_WAIT_TID_RESP;
+
+	hfi1_schedule_tid_send(qp);
+	goto ack_done;
+
+ack_op_err:
+	status = IB_WC_LOC_QP_OP_ERR;
+ack_err:
+	rvt_error_qp(qp, status);
+ack_done:
+	spin_unlock_irqrestore(&qp->s_lock, flags);
+	if (is_fecn)
+		hfi1_send_rc_ack(packet, is_fecn);
 }
 
 void hfi1_rc_rcv_tid_rdma_read_req(struct hfi1_packet *packet)
@@ -1928,6 +2831,14 @@  void hfi1_rc_rcv_tid_rdma_read_req(struct hfi1_packet *packet)
 
 	qp->r_head_ack_queue = next;
 
+	/*
+	 * For all requests other than TID WRITE which are added to the ack
+	 * queue, qpriv->r_tid_alloc follows qp->r_head_ack_queue. It is ok to
+	 * do this because of interlocks between these and TID WRITE
+	 * requests. The same change has also been made in hfi1_rc_rcv().
+	 */
+	qpriv->r_tid_alloc = qp->r_head_ack_queue;
+
 	/* Schedule the send tasklet. */
 	qp->s_flags |= RVT_S_RESP_PENDING;
 	hfi1_schedule_send(qp);
@@ -1988,7 +2899,7 @@  void hfi1_rc_rcv_tid_rdma_read_resp(struct hfi1_packet *packet)
 	/*
 	 * 1. Find matching SWQE
 	 * 2. Check that the entire segment has been read.
-	 * 3. Remove RVT_S_WAIT_TID_RESP from s_flags.
+	 * 3. Remove HFI1_S_WAIT_TID_RESP from s_flags.
 	 * 4. Free the TID flow resources.
 	 * 5. Kick the send engine (hfi1_schedule_send())
 	 */
@@ -2082,10 +2993,420 @@  void hfi1_rc_rcv_tid_rdma_read_resp(struct hfi1_packet *packet)
 
 void hfi1_rc_rcv_tid_rdma_resync(struct hfi1_packet *packet)
 {
+	struct ib_other_headers *ohdr = packet->ohdr;
+	struct rvt_qp *qp = packet->qp;
+	struct hfi1_qp_priv *qpriv = qp->priv;
+	struct hfi1_ctxtdata *rcd = qpriv->rcd;
+	struct hfi1_ibdev *dev = to_idev(qp->ibqp.device);
+	struct rvt_ack_entry *e;
+	struct tid_rdma_request *req;
+	struct tid_rdma_flow *flow;
+	struct tid_flow_state *fs = &qpriv->flow_state;
+	u32 psn, generation, idx, gen_next;
+	bool is_fecn;
+	unsigned long flags;
+
+	is_fecn = process_ecn(qp, packet, false);
+	psn = mask_psn(be32_to_cpu(ohdr->bth[2]));
+
+	generation = mask_psn(psn + 1) >> HFI1_KDETH_BTH_SEQ_SHIFT;
+	spin_lock_irqsave(&qp->s_lock, flags);
+
+	gen_next = (fs->generation == KERN_GENERATION_RESERVED) ?
+		generation : kern_flow_generation_next(fs->generation);
+	/*
+	 * RESYNC packet contains the "next" generation and can only be
+	 * from the current or previous generations
+	 */
+	if (generation != mask_generation(gen_next - 1) &&
+	    generation != gen_next)
+		goto bail;
+	/* Already processing a resync */
+	if (qpriv->resync)
+		goto bail;
+
+	spin_lock(&rcd->exp_lock);
+	if (fs->index >= RXE_NUM_TID_FLOWS) {
+		/*
+		 * If we don't have a flow, save the generation so it can be
+		 * applied when a new flow is allocated
+		 */
+		fs->generation = generation;
+	} else {
+		/* Reprogram the QP flow with new generation */
+		rcd->flows[fs->index].generation = generation;
+		fs->generation = kern_setup_hw_flow(rcd, fs->index);
+	}
+	fs->psn = 0;
+	/*
+	 * Disable SW PSN checking since a RESYNC is equivalent to a
+	 * sync point and the flow has/will be reprogrammed
+	 */
+	qpriv->s_flags &= ~HFI1_R_TID_SW_PSN;
+	/*
+	 * Reset all TID flow information with the new generation.
+	 * This is done for all requests and segments after the
+	 * last received segment
+	 */
+	for (idx = qpriv->r_tid_tail; ; idx++) {
+		u16 flow_idx;
+
+		if (idx > rvt_size_atomic(&dev->rdi))
+			idx = 0;
+		e = &qp->s_ack_queue[idx];
+		if (e->opcode == TID_OP(WRITE_REQ)) {
+			req = ack_to_tid_req(e);
+			/* start from last unacked segment */
+			for (flow_idx = req->clear_tail;
+			     CIRC_CNT(req->setup_head, flow_idx,
+				      req->n_max_flows);
+			     flow_idx = CIRC_NEXT(flow_idx, req->n_max_flows)) {
+				u32 lpsn;
+				u32 next;
+
+				flow = &req->flows[flow_idx];
+				lpsn = full_flow_psn(flow,
+						     flow->flow_state.lpsn);
+				next = flow->flow_state.r_next_psn;
+				flow->npkts = delta_psn(lpsn, next - 1);
+				flow->flow_state.generation = fs->generation;
+				flow->flow_state.spsn = fs->psn;
+				flow->flow_state.lpsn =
+					flow->flow_state.spsn + flow->npkts - 1;
+				flow->flow_state.r_next_psn =
+					full_flow_psn(flow,
+						      flow->flow_state.spsn);
+				fs->psn += flow->npkts;
+			}
+		}
+		if (idx == qp->s_tail_ack_queue)
+			break;
+	}
+
+	spin_unlock(&rcd->exp_lock);
+	qpriv->resync = true;
+	/* RESYNC request always gets a TID RDMA ACK. */
+	qpriv->s_nak_state = 0;
+	qpriv->s_flags |= RVT_S_ACK_PENDING;
+	hfi1_schedule_tid_send(qp);
+bail:
+	spin_unlock_irqrestore(&qp->s_lock, flags);
 }
 
 void hfi1_rc_rcv_tid_rdma_ack(struct hfi1_packet *packet)
 {
+	struct ib_other_headers *ohdr = packet->ohdr;
+	struct rvt_qp *qp = packet->qp;
+	struct hfi1_qp_priv *qpriv = qp->priv;
+	struct rvt_swqe *wqe;
+	struct tid_rdma_request *req;
+	struct tid_rdma_flow *flow;
+	u32 aeth, psn, req_psn, ack_psn, fspsn, resync_psn, ack_kpsn;
+	bool is_fecn;
+	unsigned long flags;
+	u16 fidx;
+
+	is_fecn = process_ecn(qp, packet, false);
+	psn = mask_psn(be32_to_cpu(ohdr->bth[2]));
+	aeth = be32_to_cpu(ohdr->u.tid_rdma.ack.aeth);
+	req_psn = mask_psn(be32_to_cpu(ohdr->u.tid_rdma.ack.verbs_psn));
+	resync_psn = mask_psn(be32_to_cpu(ohdr->u.tid_rdma.ack.tid_flow_psn));
+
+	spin_lock_irqsave(&qp->s_lock, flags);
+	/* If we are waiting for an ACK to RESYNC, drop any other packets */
+	if ((qp->s_flags & HFI1_S_WAIT_HALT) &&
+	    cmp_psn(psn, qpriv->s_resync_psn))
+		goto ack_op_err;
+
+	ack_psn = req_psn;
+	if (hfi1_tid_rdma_is_resync_psn(psn))
+		ack_kpsn = resync_psn;
+	else
+		ack_kpsn = psn;
+	if (aeth >> 29) {
+		ack_psn--;
+		ack_kpsn--;
+	}
+
+	wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
+
+	if (wqe->wr.opcode != IB_WR_TID_RDMA_WRITE)
+		goto ack_op_err;
+
+	req = wqe_to_tid_req(wqe);
+	flow = &req->flows[req->acked_tail];
+
+	/* Drop stale ACK/NAK */
+	if (cmp_psn(psn, full_flow_psn(flow, flow->flow_state.spsn)) < 0)
+		goto ack_op_err;
+
+	while (cmp_psn(ack_kpsn,
+		       full_flow_psn(flow, flow->flow_state.lpsn)) >= 0 &&
+	       req->ack_seg < req->cur_seg) {
+		req->ack_seg++;
+		/* advance acked segment pointer */
+		req->acked_tail = CIRC_NEXT(req->acked_tail, req->n_max_flows);
+		req->r_last_acked = flow->flow_state.resp_ib_psn;
+		if (req->ack_seg == req->total_segs) {
+			req->state = TID_REQUEST_COMPLETE;
+			wqe = do_rc_completion(qp, wqe,
+					       to_iport(qp->ibqp.device,
+							qp->port_num));
+			atomic_dec(&qpriv->n_tid_requests);
+			if (qp->s_acked == qp->s_tail)
+				break;
+			if (wqe->wr.opcode != IB_WR_TID_RDMA_WRITE)
+				break;
+			req = wqe_to_tid_req(wqe);
+		}
+		flow = &req->flows[req->acked_tail];
+	}
+
+	switch (aeth >> 29) {
+	case 0:         /* ACK */
+		if (qpriv->s_flags & RVT_S_WAIT_ACK)
+			qpriv->s_flags &= ~RVT_S_WAIT_ACK;
+		if (!hfi1_tid_rdma_is_resync_psn(psn)) {
+			/* Check if there is any pending TID ACK */
+			if (wqe->wr.opcode == IB_WR_TID_RDMA_WRITE &&
+			    req->ack_seg < req->cur_seg)
+				hfi1_mod_tid_retry_timer(qp);
+			else
+				hfi1_stop_tid_retry_timer(qp);
+			hfi1_schedule_send(qp);
+		} else {
+			u32 spsn, fpsn, last_acked, generation;
+			struct tid_rdma_request *rptr;
+
+			/* ACK(RESYNC) */
+			hfi1_stop_tid_retry_timer(qp);
+			/* Allow new requests (see hfi1_make_tid_rdma_pkt) */
+			qp->s_flags &= ~HFI1_S_WAIT_HALT;
+			/*
+			 * Clear RVT_S_SEND_ONE flag in case that the TID RDMA
+			 * ACK is received after the TID retry timer is fired
+			 * again. In this case, do not send any more TID
+			 * RESYNC request or wait for any more TID ACK packet.
+			 */
+			qpriv->s_flags &= ~RVT_S_SEND_ONE;
+			hfi1_schedule_send(qp);
+
+			if ((qp->s_acked == qpriv->s_tid_tail &&
+			     req->ack_seg == req->total_segs) ||
+			    qp->s_acked == qp->s_tail) {
+				qpriv->s_state = TID_OP(WRITE_DATA_LAST);
+				goto done;
+			}
+
+			if (req->ack_seg == req->comp_seg) {
+				qpriv->s_state = TID_OP(WRITE_DATA);
+				goto done;
+			}
+
+			/*
+			 * The PSN to start with is the next PSN after the
+			 * RESYNC PSN.
+			 */
+			psn = mask_psn(psn + 1);
+			generation = psn >> HFI1_KDETH_BTH_SEQ_SHIFT;
+			spsn = 0;
+
+			/*
+			 * Update to the correct WQE when we get an ACK(RESYNC)
+			 * in the middle of a request.
+			 */
+			if (delta_psn(ack_psn, wqe->lpsn))
+				wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
+			req = wqe_to_tid_req(wqe);
+			flow = &req->flows[req->acked_tail];
+			/*
+			 * RESYNC re-numbers the PSN ranges of all remaining
+			 * segments. Also, PSN's start from 0 in the middle of a
+			 * segment and the first segment size is less than the
+			 * default number of packets. flow->resync_npkts is used
+			 * to track the number of packets from the start of the
+			 * real segment to the point of 0 PSN after the RESYNC
+			 * in order to later correctly rewind the SGE.
+			 */
+			fpsn = full_flow_psn(flow, flow->flow_state.spsn);
+			req->r_ack_psn = psn;
+			flow->resync_npkts +=
+				delta_psn(mask_psn(resync_psn + 1), fpsn);
+			/*
+			 * Renumber all packet sequence number ranges
+			 * based on the new generation.
+			 */
+			last_acked = qp->s_acked;
+			rptr = req;
+			while (1) {
+				/* start from last acked segment */
+				for (fidx = rptr->acked_tail;
+				     CIRC_CNT(rptr->setup_head, fidx,
+					      rptr->n_max_flows);
+				     fidx = CIRC_NEXT(fidx,
+						      rptr->n_max_flows)) {
+					u32 lpsn;
+					u32 gen;
+
+					flow = &rptr->flows[fidx];
+					gen = flow->flow_state.generation;
+					if (WARN_ON(gen == generation &&
+						    flow->flow_state.spsn !=
+						     spsn))
+						continue;
+					lpsn = flow->flow_state.lpsn;
+					lpsn = full_flow_psn(flow, lpsn);
+					flow->npkts =
+						delta_psn(lpsn,
+							  mask_psn(resync_psn)
+							  );
+					flow->flow_state.generation =
+						generation;
+					flow->flow_state.spsn = spsn;
+					flow->flow_state.lpsn =
+						flow->flow_state.spsn +
+						flow->npkts - 1;
+					flow->pkt = 0;
+					spsn += flow->npkts;
+					resync_psn += flow->npkts;
+				}
+				if (++last_acked == qpriv->s_tid_cur + 1)
+					break;
+				if (last_acked == qp->s_size)
+					last_acked = 0;
+				wqe = rvt_get_swqe_ptr(qp, last_acked);
+				rptr = wqe_to_tid_req(wqe);
+			}
+			req->cur_seg = req->ack_seg;
+			qpriv->s_tid_tail = qp->s_acked;
+			qpriv->s_state = TID_OP(WRITE_REQ);
+			hfi1_schedule_tid_send(qp);
+		}
+done:
+		qpriv->s_retry = qp->s_retry_cnt;
+		break;
+
+	case 3:         /* NAK */
+		hfi1_stop_tid_retry_timer(qp);
+		switch ((aeth >> IB_AETH_CREDIT_SHIFT) &
+			IB_AETH_CREDIT_MASK) {
+		case 0: /* PSN sequence error */
+			flow = &req->flows[req->acked_tail];
+			fspsn = full_flow_psn(flow, flow->flow_state.spsn);
+			req->r_ack_psn = mask_psn(be32_to_cpu(ohdr->bth[2]));
+			req->cur_seg = req->ack_seg;
+			qpriv->s_tid_tail = qp->s_acked;
+			qpriv->s_state = TID_OP(WRITE_REQ);
+			qpriv->s_retry = qp->s_retry_cnt;
+			hfi1_schedule_tid_send(qp);
+			break;
+
+		default:
+			break;
+		}
+		break;
+
+	default:
+		break;
+	}
+
+ack_op_err:
+	spin_unlock_irqrestore(&qp->s_lock, flags);
+}
+
+static void hfi1_tid_timeout(struct timer_list *t)
+{
+	struct hfi1_qp_priv *qpriv = from_timer(qpriv, t, s_tid_timer);
+	struct rvt_qp *qp = qpriv->owner;
+	struct rvt_dev_info *rdi = ib_to_rvt(qp->ibqp.device);
+	unsigned long flags;
+	u32 i;
+
+	spin_lock_irqsave(&qp->r_lock, flags);
+	spin_lock(&qp->s_lock);
+	if (qpriv->s_flags & HFI1_R_TID_RSC_TIMER) {
+		dd_dev_warn(dd_from_ibdev(qp->ibqp.device), "[QP%u] %s %d\n",
+			    qp->ibqp.qp_num, __func__, __LINE__);
+		hfi1_stop_tid_reap_timer(qp);
+		/*
+		 * Go though the entire ack queue and clear any outstanding
+		 * HW flow and RcvArray resources.
+		 */
+		hfi1_kern_clear_hw_flow(qpriv->rcd, qp);
+		for (i = 0; i < rvt_max_atomic(rdi); i++) {
+			struct tid_rdma_request *req =
+				ack_to_tid_req(&qp->s_ack_queue[i]);
+
+			hfi1_kern_exp_rcv_clear_all(req);
+		}
+		spin_unlock(&qp->s_lock);
+		if (qp->ibqp.event_handler) {
+			struct ib_event ev;
+
+			ev.device = qp->ibqp.device;
+			ev.element.qp = &qp->ibqp;
+			ev.event = IB_EVENT_QP_FATAL;
+			qp->ibqp.event_handler(&ev, qp->ibqp.qp_context);
+		}
+		rvt_rc_error(qp, IB_WC_RESP_TIMEOUT_ERR);
+		goto unlock_r_lock;
+	}
+	spin_unlock(&qp->s_lock);
+unlock_r_lock:
+	spin_unlock_irqrestore(&qp->r_lock, flags);
+}
+
+static inline struct rvt_ack_entry *
+find_prev_entry_kdeth(struct rvt_qp *qp, u32 psn, u8 *prev, u8 *prev_ack,
+		      bool *scheduled, u16 *fidx)
+	__must_hold(&qp->s_lock)
+{
+	struct rvt_ack_entry *e = NULL;
+	struct tid_rdma_request *req;
+	struct tid_rdma_flow *flow;
+	u32 ibpsn = KDETH_INVALID_PSN;
+	u16 idx = 0;
+	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;
+		}
+		req = ack_to_tid_req(e);
+		flow = __find_flow_ranged(req, req->n_max_flows - 1, 0,
+					  psn, &idx);
+		if (flow) {
+			ibpsn = flow->flow_state.resp_ib_psn;
+			if (cmp_psn(ibpsn, e->psn) >= 0) {
+				if (p == qp->s_tail_ack_queue &&
+				    cmp_psn(ibpsn, e->lpsn) <= 0)
+					s = false;
+				break;
+			}
+		}
+	}
+	if (prev)
+		*prev = p;
+	if (prev_ack)
+		*prev_ack = i;
+	if (scheduled)
+		*scheduled = s;
+	if (fidx)
+		*fidx = idx;
+	return e;
 }
 
 void hfi1_kern_read_tid_flow_free(struct rvt_qp *qp)
@@ -2100,6 +3421,44 @@  bool hfi1_handle_kdeth_eflags(struct hfi1_ctxtdata *rcd,
 	return true;
 }
 
+static void hfi1_tid_retry_timeout(struct timer_list *t)
+{
+	struct hfi1_qp_priv *priv = from_timer(priv, t, s_tid_retry_timer);
+	struct rvt_qp *qp = priv->owner;
+	struct rvt_swqe *wqe;
+	unsigned long flags;
+	struct tid_rdma_request *req;
+
+	spin_lock_irqsave(&qp->r_lock, flags);
+	spin_lock(&qp->s_lock);
+	if (priv->s_flags & HFI1_S_TID_RETRY_TIMER) {
+		hfi1_stop_tid_retry_timer(qp);
+		if (!priv->s_retry) {
+			wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
+			hfi1_send_complete(qp, wqe,
+					   IB_WC_RETRY_EXC_ERR);
+			rvt_error_qp(qp, IB_WC_WR_FLUSH_ERR);
+		} else {
+			wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
+			req = wqe_to_tid_req(wqe);
+
+			priv->s_flags &= ~RVT_S_WAIT_ACK;
+			/* Only send one packet (the RESYNC) */
+			priv->s_flags |= RVT_S_SEND_ONE;
+			/*
+			 * No additional request shall be made by this QP until
+			 * the RESYNC has been complete.
+			 */
+			qp->s_flags |= HFI1_S_WAIT_HALT;
+			priv->s_state = TID_OP(RESYNC);
+			priv->s_retry--;
+			hfi1_schedule_tid_send(qp);
+		}
+	}
+	spin_unlock(&qp->s_lock);
+	spin_unlock_irqrestore(&qp->r_lock, flags);
+}
+
 static bool _hfi1_schedule_tid_send(struct rvt_qp *qp)
 {
 	struct hfi1_qp_priv *priv = qp->priv;
@@ -2131,12 +3490,12 @@  bool hfi1_schedule_tid_send(struct rvt_qp *qp)
 {
 	lockdep_assert_held(&qp->s_lock);
 	if (hfi1_send_tid_ok(qp)) {
-	/*
-	 * The following call returns true if the qp is not on the
-	 * queue and false if the qp is already on the queue before
-	 * this call. Either way, the qp will be on the queue when the
-	 * call returns.
-	 */
+		/*
+		 * The following call returns true if the qp is not on the
+		 * queue and false if the qp is already on the queue before
+		 * this call. Either way, the qp will be on the queue when the
+		 * call returns.
+		 */
 		_hfi1_schedule_tid_send(qp);
 		return true;
 	}
@@ -2186,10 +3545,21 @@  int hfi1_qp_priv_init(struct rvt_dev_info *rdi, struct rvt_qp *qp,
 	spin_lock_init(&qpriv->opfn.lock);
 	INIT_WORK(&qpriv->opfn.opfn_work, opfn_send_conn_request);
 	INIT_WORK(&qpriv->tid_rdma.trigger_work, tid_rdma_trigger_resume);
+	qpriv->r_tid_tail = qp->s_tail_ack_queue;
 	qpriv->flow_state.psn = 0;
 	qpriv->flow_state.index = RXE_NUM_TID_FLOWS;
 	qpriv->flow_state.last_index = RXE_NUM_TID_FLOWS;
 	qpriv->flow_state.generation = KERN_GENERATION_RESERVED;
+	qpriv->s_state = TID_OP(WRITE_RESP);
+	qpriv->s_tid_cur = HFI1_QP_WQE_INVALID;
+	qpriv->s_tid_tail = HFI1_QP_WQE_INVALID;
+	qpriv->r_tid_tail = HFI1_QP_WQE_INVALID;
+	qpriv->r_tid_ack = HFI1_QP_WQE_INVALID;
+	atomic_set(&qpriv->n_requests, 0);
+	atomic_set(&qpriv->n_tid_requests, 0);
+	timer_setup(&qpriv->s_tid_timer, hfi1_tid_timeout, 0);
+	timer_setup(&qpriv->s_tid_retry_timer, hfi1_tid_retry_timeout, 0);
+	INIT_LIST_HEAD(&qpriv->tid_wait);
 
 	if (init_attr->qp_type == IB_QPT_RC && HFI1_CAP_IS_KSET(TID_RDMA)) {
 		struct hfi1_devdata *dd = qpriv->rcd->dd;
@@ -2199,7 +3569,6 @@  int hfi1_qp_priv_init(struct rvt_dev_info *rdi, struct rvt_qp *qp,
 					    GFP_KERNEL, dd->node);
 		if (!qpriv->pages)
 			return -ENOMEM;
-
 		for (i = 0; i < qp->s_size; i++) {
 			struct hfi1_swqe_priv *priv;
 			struct rvt_swqe *wqe = rvt_get_swqe_ptr(qp, i);
@@ -2285,6 +3654,49 @@  void hfi1_qp_priv_tid_free(struct rvt_dev_info *rdi, struct rvt_qp *qp)
 
 void hfi1_qp_kern_exp_rcv_clear_all(struct rvt_qp *qp)
 {
+	int i, ret;
+	struct hfi1_qp_priv *qpriv = qp->priv;
+	struct tid_flow_state *fs;
+
+	if (qp->ibqp.qp_type != IB_QPT_RC || !HFI1_CAP_IS_KSET(TID_RDMA))
+		return;
+
+	/*
+	 * First, clear the flow to help prevent any delayed packets from
+	 * being delivered.
+	 */
+	fs = &qpriv->flow_state;
+	if (fs->index != RXE_NUM_TID_FLOWS)
+		hfi1_kern_clear_hw_flow(qpriv->rcd, qp);
+
+	for (i = qp->s_acked; i != qp->s_head;) {
+		struct rvt_swqe *wqe = rvt_get_swqe_ptr(qp, i);
+
+		if (++i == qp->s_size)
+			i = 0;
+		/* Free only locally allocated TID entries */
+		if (wqe->wr.opcode != IB_WR_TID_RDMA_READ)
+			continue;
+		do {
+			struct hfi1_swqe_priv *priv = wqe->priv;
+
+			ret = hfi1_kern_exp_rcv_clear(&priv->tid_req);
+		} while (!ret);
+	}
+	for (i = qp->s_acked_ack_queue; i != qp->r_head_ack_queue;) {
+		struct rvt_ack_entry *e = &qp->s_ack_queue[i];
+
+		if (++i == rvt_max_atomic(ib_to_rvt(qp->ibqp.device)))
+			i = 0;
+		/* Free only locally allocated TID entries */
+		if (e->opcode != TID_OP(WRITE_REQ))
+			continue;
+		do {
+			struct hfi1_ack_priv *priv = e->priv;
+
+			ret = hfi1_kern_exp_rcv_clear(&priv->tid_req);
+		} while (!ret);
+	}
 }
 
 u64 hfi1_access_sw_tid_wait(const struct cntr_entry *entry,
@@ -2295,25 +3707,527 @@  u64 hfi1_access_sw_tid_wait(const struct cntr_entry *entry,
 	return dd->verbs_dev.n_tidwait;
 }
 
+static bool build_tid_rdma_packet(struct rvt_swqe *wqe,
+				  struct ib_other_headers *ohdr,
+				  u32 *bth1, u32 *bth2, u32 *len)
+{
+	struct tid_rdma_request *req = wqe_to_tid_req(wqe);
+	struct tid_rdma_flow *flow = &req->flows[req->clear_tail];
+	struct tid_rdma_params *remote;
+	struct rvt_qp *qp = req->qp;
+	struct hfi1_qp_priv *qpriv = qp->priv;
+	u32 tidentry = flow->fstate->tid_entry[flow->tid_idx];
+	u32 tidlen = EXP_TID_GET(tidentry, LEN) << PAGE_SHIFT;
+	struct tid_rdma_write_data *wd = &ohdr->u.tid_rdma.w_data;
+	u32 next_offset, om = KDETH_OM_LARGE;
+	bool last_pkt;
+
+	if (!tidlen) {
+		hfi1_send_complete(qp, wqe, IB_WC_REM_INV_RD_REQ_ERR);
+		rvt_error_qp(qp, IB_WC_REM_INV_RD_REQ_ERR);
+	}
+
+	*len = min_t(u32, qp->pmtu, tidlen - flow->tid_offset);
+	flow->sent += *len;
+	next_offset = flow->tid_offset + *len;
+	last_pkt = (flow->tid_idx == (flow->tidcnt - 1) &&
+		    next_offset >= tidlen) || (flow->sent >= flow->length);
+
+	rcu_read_lock();
+	remote = rcu_dereference(qpriv->tid_rdma.remote);
+	KDETH_RESET(wd->kdeth0, KVER, 0x1);
+	KDETH_SET(wd->kdeth0, SH, !last_pkt);
+	KDETH_SET(wd->kdeth0, INTR, !!(!last_pkt && remote->urg));
+	KDETH_SET(wd->kdeth0, TIDCTRL, EXP_TID_GET(tidentry, CTRL));
+	KDETH_SET(wd->kdeth0, TID, EXP_TID_GET(tidentry, IDX));
+	KDETH_SET(wd->kdeth0, OM, om == KDETH_OM_LARGE);
+	KDETH_SET(wd->kdeth0, OFFSET, flow->tid_offset / om);
+	KDETH_RESET(wd->kdeth1, JKEY, remote->jkey);
+	wd->verbs_qp = cpu_to_be32(qp->remote_qpn);
+	rcu_read_unlock();
+
+	*bth1 = flow->tid_qpn;
+	*bth2 = mask_psn(((flow->flow_state.spsn + flow->pkt++) &
+			 HFI1_KDETH_BTH_SEQ_MASK) |
+			 (flow->flow_state.generation <<
+			  HFI1_KDETH_BTH_SEQ_SHIFT));
+	if (last_pkt) {
+		/* PSNs are zero-based, so +1 to count number of packets */
+		if (flow->flow_state.lpsn + 1 +
+		    rvt_div_round_up_mtu(qp, req->seg_len) >
+		    MAX_TID_FLOW_PSN)
+			req->state = TID_REQUEST_SYNC;
+		*bth2 |= IB_BTH_REQ_ACK;
+	}
+
+	if (next_offset >= tidlen) {
+		flow->tid_offset = 0;
+		flow->tid_idx++;
+	} else {
+		flow->tid_offset = next_offset;
+	}
+	return last_pkt;
+}
+
+static u32 build_tid_rdma_write_ack(struct rvt_qp *qp, struct rvt_ack_entry *e,
+				    struct ib_other_headers *ohdr, u16 iflow,
+				    u32 *bth1, u32 *bth2)
+{
+	struct hfi1_qp_priv *qpriv = qp->priv;
+	struct tid_flow_state *fs = &qpriv->flow_state;
+	struct tid_rdma_request *req = ack_to_tid_req(e);
+	struct tid_rdma_flow *flow = &req->flows[iflow];
+	struct tid_rdma_params *remote;
+
+	rcu_read_lock();
+	remote = rcu_dereference(qpriv->tid_rdma.remote);
+	KDETH_RESET(ohdr->u.tid_rdma.ack.kdeth1, JKEY, remote->jkey);
+	ohdr->u.tid_rdma.ack.verbs_qp = cpu_to_be32(qp->remote_qpn);
+	*bth1 = remote->qp;
+	rcu_read_unlock();
+
+	if (qpriv->resync) {
+		*bth2 = mask_psn((fs->generation <<
+				  HFI1_KDETH_BTH_SEQ_SHIFT) - 1);
+		ohdr->u.tid_rdma.ack.aeth = rvt_compute_aeth(qp);
+	} else if (qpriv->s_nak_state) {
+		*bth2 = mask_psn(qpriv->s_nak_psn);
+		ohdr->u.tid_rdma.ack.aeth =
+			cpu_to_be32((qp->r_msn & IB_MSN_MASK) |
+				    (qpriv->s_nak_state <<
+				     IB_AETH_CREDIT_SHIFT));
+	} else {
+		*bth2 = full_flow_psn(flow, flow->flow_state.lpsn);
+		ohdr->u.tid_rdma.ack.aeth = rvt_compute_aeth(qp);
+	}
+	KDETH_RESET(ohdr->u.tid_rdma.ack.kdeth0, KVER, 0x1);
+	ohdr->u.tid_rdma.ack.tid_flow_qp =
+		cpu_to_be32(qpriv->tid_rdma.local.qp |
+			    ((flow->idx & TID_RDMA_DESTQP_FLOW_MASK) <<
+			     TID_RDMA_DESTQP_FLOW_SHIFT) |
+			    qpriv->rcd->ctxt);
+
+	ohdr->u.tid_rdma.ack.tid_flow_psn = 0;
+	ohdr->u.tid_rdma.ack.verbs_psn =
+		cpu_to_be32(flow->flow_state.resp_ib_psn);
+
+	if (qpriv->resync) {
+		/*
+		 * If the PSN before the current expect KDETH PSN is the
+		 * RESYNC PSN, then we never received a good TID RDMA WRITE
+		 * DATA packet after a previous RESYNC.
+		 * In this case, the next expected KDETH PSN stays the same.
+		 */
+		if (hfi1_tid_rdma_is_resync_psn(qpriv->r_next_psn_kdeth - 1)) {
+			ohdr->u.tid_rdma.ack.tid_flow_psn =
+				cpu_to_be32(qpriv->r_next_psn_kdeth_save);
+		} else {
+			/*
+			 * Because the KDETH PSNs jump during a RESYNC, it's
+			 * not possible to infer (or compute) the previous value
+			 * of r_next_psn_kdeth in the case of back-to-back
+			 * RESYNC packets. Therefore, we save it.
+			 */
+			qpriv->r_next_psn_kdeth_save =
+				qpriv->r_next_psn_kdeth - 1;
+			ohdr->u.tid_rdma.ack.tid_flow_psn =
+				cpu_to_be32(qpriv->r_next_psn_kdeth_save);
+			qpriv->r_next_psn_kdeth = mask_psn(*bth2 + 1);
+		}
+		qpriv->resync = false;
+	}
+
+	return sizeof(ohdr->u.tid_rdma.ack) / sizeof(u32);
+}
+
+static int make_tid_rdma_ack(struct rvt_qp *qp,
+			     struct ib_other_headers *ohdr,
+			     struct hfi1_pkt_state *ps)
+{
+	struct rvt_ack_entry *e;
+	struct hfi1_qp_priv *qpriv = qp->priv;
+	struct hfi1_ibdev *dev = to_idev(qp->ibqp.device);
+	u32 hwords, next;
+	u32 len = 0;
+	u32 bth1 = 0, bth2 = 0;
+	int middle = 0;
+	u16 flow;
+	struct tid_rdma_request *req, *nreq;
+
+	/* Don't send an ACK if we aren't supposed to. */
+	if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK))
+		goto bail;
+
+	/* header size in 32-bit words LRH+BTH = (8+12)/4. */
+	hwords = 5;
+
+	e = &qp->s_ack_queue[qpriv->r_tid_ack];
+	req = ack_to_tid_req(e);
+	/*
+	 * In the RESYNC case, we are exactly one segment past the
+	 * previously sent ack or at the previously sent NAK. So to send
+	 * the resync ack, we go back one segment (which might be part of
+	 * the previous request) and let the do-while loop execute again.
+	 * The advantage of executing the do-while loop is that any data
+	 * received after the previous ack is automatically acked in the
+	 * RESYNC ack. It turns out that for the do-while loop we only need
+	 * to pull back qpriv->r_tid_ack, not the segment
+	 * indices/counters. The scheme works even if the previous request
+	 * was not a TID WRITE request.
+	 */
+	if (qpriv->resync) {
+		if (!req->ack_seg || req->ack_seg == req->total_segs)
+			qpriv->r_tid_ack = !qpriv->r_tid_ack ?
+				rvt_size_atomic(&dev->rdi) :
+				qpriv->r_tid_ack - 1;
+		e = &qp->s_ack_queue[qpriv->r_tid_ack];
+		req = ack_to_tid_req(e);
+	}
+
+	/*
+	 * If we've sent all the ACKs that we can, we are done
+	 * until we get more segments...
+	 */
+	if (!qpriv->s_nak_state && !qpriv->resync &&
+	    req->ack_seg == req->comp_seg)
+		goto bail;
+
+	do {
+		/*
+		 * To deal with coalesced ACKs, the acked_tail pointer
+		 * into the flow array is used. The distance between it
+		 * and the clear_tail is the number of flows that are
+		 * being ACK'ed.
+		 */
+		req->ack_seg +=
+			/* Get up-to-date value */
+			CIRC_CNT(req->clear_tail, req->acked_tail,
+				 req->n_max_flows);
+		/* Advance acked index */
+		req->acked_tail = req->clear_tail;
+
+		/*
+		 * req->clear_tail points to the segment currently being
+		 * received. So, when sending an ACK, the previous
+		 * segment is being ACK'ed.
+		 */
+		flow = CIRC_PREV(req->acked_tail, req->n_max_flows);
+		if (req->ack_seg != req->total_segs)
+			break;
+		req->state = TID_REQUEST_COMPLETE;
+
+		next = qpriv->r_tid_ack + 1;
+		if (next > rvt_size_atomic(&dev->rdi))
+			next = 0;
+		qpriv->r_tid_ack = next;
+		if (qp->s_ack_queue[next].opcode != TID_OP(WRITE_REQ))
+			break;
+		nreq = ack_to_tid_req(&qp->s_ack_queue[next]);
+		if (!nreq->comp_seg || nreq->ack_seg == nreq->comp_seg)
+			break;
+
+		/* Move to the next ack entry now */
+		e = &qp->s_ack_queue[qpriv->r_tid_ack];
+		req = ack_to_tid_req(e);
+	} while (1);
+
+	/*
+	 * At this point qpriv->r_tid_ack == qpriv->r_tid_tail but e and
+	 * req could be pointing at the previous ack queue entry
+	 */
+	if (qpriv->s_nak_state ||
+	    (qpriv->resync &&
+	     !hfi1_tid_rdma_is_resync_psn(qpriv->r_next_psn_kdeth - 1) &&
+	     (cmp_psn(qpriv->r_next_psn_kdeth - 1,
+		      full_flow_psn(&req->flows[flow],
+				    req->flows[flow].flow_state.lpsn)) > 0))) {
+		/*
+		 * A NAK will implicitly acknowledge all previous TID RDMA
+		 * requests. Therefore, we NAK with the req->acked_tail
+		 * segment for the request at qpriv->r_tid_ack (same at
+		 * this point as the req->clear_tail segment for the
+		 * qpriv->r_tid_tail request)
+		 */
+		e = &qp->s_ack_queue[qpriv->r_tid_ack];
+		req = ack_to_tid_req(e);
+		flow = req->acked_tail;
+	} else if (req->ack_seg == req->total_segs &&
+		   qpriv->s_flags & HFI1_R_TID_WAIT_INTERLCK)
+		qpriv->s_flags &= ~HFI1_R_TID_WAIT_INTERLCK;
+
+	hwords += build_tid_rdma_write_ack(qp, e, ohdr, flow, &bth1,
+					   &bth2);
+	len = 0;
+	qpriv->s_flags &= ~RVT_S_ACK_PENDING;
+	ps->s_txreq->hdr_dwords = hwords;
+	ps->s_txreq->sde = qpriv->s_sde;
+	ps->s_txreq->s_cur_size = len;
+	ps->s_txreq->ss = NULL;
+	hfi1_make_ruc_header(qp, ohdr, (TID_OP(ACK) << 24), bth1, bth2, middle,
+			     ps);
+	return 1;
+bail:
+	/*
+	 * Ensure s_rdma_ack_cnt changes are committed prior to resetting
+	 * RVT_S_RESP_PENDING
+	 */
+	smp_wmb();
+	qpriv->s_flags &= ~RVT_S_ACK_PENDING;
+	return 0;
+}
+
+/*
+ * Call this function when the last TID RDMA WRITE DATA packet for a request
+ * is built.
+ */
+static void update_tid_tail(struct rvt_qp *qp)
+	__must_hold(&qp->s_lock)
+{
+	struct hfi1_qp_priv *priv = qp->priv;
+	u32 i;
+	struct rvt_swqe *wqe;
+
+	lockdep_assert_held(&qp->s_lock);
+	/* Can't move beyond s_tid_cur */
+	if (priv->s_tid_tail == priv->s_tid_cur)
+		return;
+	for (i = priv->s_tid_tail + 1; ; i++) {
+		if (i == qp->s_size)
+			i = 0;
+
+		if (i == priv->s_tid_cur)
+			break;
+		wqe = rvt_get_swqe_ptr(qp, i);
+		if (wqe->wr.opcode == IB_WR_TID_RDMA_WRITE)
+			break;
+	}
+	priv->s_tid_tail = i;
+	priv->s_state = TID_OP(WRITE_RESP);
+}
+
+static u32 build_tid_rdma_resync(struct rvt_qp *qp, struct rvt_swqe *wqe,
+				 struct ib_other_headers *ohdr, u32 *bth1,
+				 u32 *bth2, u16 fidx)
+{
+	struct hfi1_qp_priv *qpriv = qp->priv;
+	struct tid_rdma_params *remote;
+	struct tid_rdma_request *req = wqe_to_tid_req(wqe);
+	struct tid_rdma_flow *flow = &req->flows[fidx];
+	u32 generation;
+
+	rcu_read_lock();
+	remote = rcu_dereference(qpriv->tid_rdma.remote);
+	KDETH_RESET(ohdr->u.tid_rdma.ack.kdeth1, JKEY, remote->jkey);
+	ohdr->u.tid_rdma.ack.verbs_qp = cpu_to_be32(qp->remote_qpn);
+	*bth1 = remote->qp;
+	rcu_read_unlock();
+
+	generation = kern_flow_generation_next(flow->flow_state.generation);
+	*bth2 = mask_psn((generation << HFI1_KDETH_BTH_SEQ_SHIFT) - 1);
+	qpriv->s_resync_psn = *bth2;
+	*bth2 |= IB_BTH_REQ_ACK;
+	KDETH_RESET(ohdr->u.tid_rdma.ack.kdeth0, KVER, 0x1);
+
+	return sizeof(ohdr->u.tid_rdma.resync) / sizeof(u32);
+}
+
 static int hfi1_make_tid_rdma_pkt(struct rvt_qp *qp, struct hfi1_pkt_state *ps)
 	__must_hold(&qp->s_lock)
 {
+	struct hfi1_qp_priv *priv = qp->priv;
+	struct rvt_swqe *wqe;
+	u32 bth1 = 0, bth2 = 0, hwords = 5, len, middle = 0;
+	struct ib_other_headers *ohdr;
+	struct rvt_sge_state *ss = &qp->s_sge;
+	struct rvt_ack_entry *e = &qp->s_ack_queue[qp->s_tail_ack_queue];
+	struct tid_rdma_request *req = ack_to_tid_req(e);
+	bool last = false;
+	u8 opcode = TID_OP(WRITE_DATA);
+
+	lockdep_assert_held(&qp->s_lock);
+	/*
+	 * Prioritize the sending of the requests and responses over the
+	 * sending of the TID RDMA data packets.
+	 */
+	if (((atomic_read(&priv->n_tid_requests) < HFI1_TID_RDMA_WRITE_CNT) &&
+	     atomic_read(&priv->n_requests) &&
+	     !(qp->s_flags & (RVT_S_BUSY | RVT_S_WAIT_ACK |
+			     HFI1_S_ANY_WAIT_IO))) ||
+	    (e->opcode == TID_OP(WRITE_REQ) && req->cur_seg < req->alloc_seg &&
+	     !(qp->s_flags & (RVT_S_BUSY | HFI1_S_ANY_WAIT_IO)))) {
+		struct iowait_work *iowork;
+
+		iowork = iowait_get_ib_work(&priv->s_iowait);
+		ps->s_txreq = get_waiting_verbs_txreq(iowork);
+		if (ps->s_txreq || hfi1_make_rc_req(qp, ps)) {
+			priv->s_flags |= HFI1_S_TID_BUSY_SET;
+			return 1;
+		}
+	}
+
+	ps->s_txreq = get_txreq(ps->dev, qp);
+	if (!ps->s_txreq)
+		goto bail_no_tx;
+
+	ohdr = &ps->s_txreq->phdr.hdr.ibh.u.oth;
+
+	if ((priv->s_flags & RVT_S_ACK_PENDING) &&
+	    make_tid_rdma_ack(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_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 (priv->s_flags & RVT_S_WAIT_ACK)
+		goto bail;
+
+	/* Check whether there is anything to do. */
+	if (priv->s_tid_tail == HFI1_QP_WQE_INVALID)
+		goto bail;
+	wqe = rvt_get_swqe_ptr(qp, priv->s_tid_tail);
+	req = wqe_to_tid_req(wqe);
+	switch (priv->s_state) {
+	case TID_OP(WRITE_REQ):
+	case TID_OP(WRITE_RESP):
+		priv->tid_ss.sge = wqe->sg_list[0];
+		priv->tid_ss.sg_list = wqe->sg_list + 1;
+		priv->tid_ss.num_sge = wqe->wr.num_sge;
+		priv->tid_ss.total_len = wqe->length;
+
+		if (priv->s_state == TID_OP(WRITE_REQ))
+			hfi1_tid_rdma_restart_req(qp, wqe, &bth2);
+		priv->s_state = TID_OP(WRITE_DATA);
+		/* fall through */
+
+	case TID_OP(WRITE_DATA):
+		/*
+		 * 1. Check whether TID RDMA WRITE RESP available.
+		 * 2. If no:
+		 *    2.1 If have more segments and no TID RDMA WRITE RESP,
+		 *        set HFI1_S_WAIT_TID_RESP
+		 *    2.2 Return indicating no progress made.
+		 * 3. If yes:
+		 *    3.1 Build TID RDMA WRITE DATA packet.
+		 *    3.2 If last packet in segment:
+		 *        3.2.1 Change KDETH header bits
+		 *        3.2.2 Advance RESP pointers.
+		 *    3.3 Return indicating progress made.
+		 */
+		wqe = rvt_get_swqe_ptr(qp, priv->s_tid_tail);
+		req = wqe_to_tid_req(wqe);
+		len = wqe->length;
+
+		if (!req->comp_seg || req->cur_seg == req->comp_seg)
+			goto bail;
+
+		last = build_tid_rdma_packet(wqe, ohdr, &bth1, &bth2, &len);
+
+		if (last) {
+			/* move pointer to next flow */
+			req->clear_tail = CIRC_NEXT(req->clear_tail,
+						    req->n_max_flows);
+			if (++req->cur_seg < req->total_segs) {
+				if (!CIRC_CNT(req->setup_head, req->clear_tail,
+					      req->n_max_flows))
+					qp->s_flags |= HFI1_S_WAIT_TID_RESP;
+			} else {
+				priv->s_state = TID_OP(WRITE_DATA_LAST);
+				opcode = TID_OP(WRITE_DATA_LAST);
+
+				/* Advance the s_tid_tail now */
+				update_tid_tail(qp);
+			}
+		}
+		hwords += sizeof(ohdr->u.tid_rdma.w_data) / sizeof(u32);
+		ss = &priv->tid_ss;
+		break;
+
+	case TID_OP(RESYNC):
+		/* Use generation from the most recently received response */
+		wqe = rvt_get_swqe_ptr(qp, priv->s_tid_cur);
+		req = wqe_to_tid_req(wqe);
+		/* If no responses for this WQE look at the previous one */
+		if (!req->comp_seg) {
+			wqe = rvt_get_swqe_ptr(qp,
+					       (!priv->s_tid_cur ? qp->s_size :
+						priv->s_tid_cur) - 1);
+			req = wqe_to_tid_req(wqe);
+		}
+		hwords += build_tid_rdma_resync(qp, wqe, ohdr, &bth1, &bth2,
+						CIRC_PREV(req->setup_head,
+							  req->n_max_flows));
+		ss = NULL;
+		len = 0;
+		opcode = TID_OP(RESYNC);
+		break;
+
+	default:
+		goto bail;
+	}
+	if (priv->s_flags & RVT_S_SEND_ONE) {
+		priv->s_flags &= ~RVT_S_SEND_ONE;
+		priv->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, (opcode << 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;
+	priv->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 the the wake up which work item to wake
+	 * up.
+	 * (A better algorithm should be found to do this and generalize the
+	 * sleep/wakeup flags.)
+	 */
+	iowait_set_flag(&priv->s_iowait, IOWAIT_PENDING_TID);
 	return 0;
 }
 
 /*
- *  "Rewind" the TID request information.
- *  This means that we reset the state back to ACTIVE,
- *  find the proper flow, set the flow index to that flow,
- *  and reset the flow information.
+ * "Rewind" the TID request information.
+ * This means that we reset the state back to ACTIVE,
+ * find the proper flow, set the flow index to that flow,
+ * and reset the flow information.
  */
 void hfi1_tid_rdma_restart_req(struct rvt_qp *qp, struct rvt_swqe *wqe,
 			       u32 *bth2)
 {
 	struct tid_rdma_request *req = wqe_to_tid_req(wqe);
 	struct tid_rdma_flow *flow;
-	int diff;
-	u32 tididx = 0;
+	struct hfi1_qp_priv *qpriv = qp->priv;
+	int diff, delta_pkts;
+	u32 tididx = 0, i;
 	u16 fidx;
 
 	if (wqe->wr.opcode == IB_WR_TID_RDMA_READ) {
@@ -2322,10 +4236,19 @@  void hfi1_tid_rdma_restart_req(struct rvt_qp *qp, struct rvt_swqe *wqe,
 		if (!flow)
 			return;
 	} else {
-		return;
+		fidx = req->acked_tail;
+		flow = &req->flows[fidx];
+		*bth2 = mask_psn(req->r_ack_psn);
 	}
 
-	diff = delta_psn(*bth2, flow->flow_state.ib_spsn);
+	if (wqe->wr.opcode == IB_WR_TID_RDMA_READ)
+		delta_pkts = delta_psn(*bth2, flow->flow_state.ib_spsn);
+	else
+		delta_pkts = delta_psn(*bth2,
+				       full_flow_psn(flow,
+						     flow->flow_state.spsn));
+
+	diff = delta_pkts + flow->resync_npkts;
 
 	flow->sent = 0;
 	flow->pkt = 0;
@@ -2334,7 +4257,7 @@  void hfi1_tid_rdma_restart_req(struct rvt_qp *qp, struct rvt_swqe *wqe,
 	if (diff) {
 		for (tididx = 0; tididx < flow->tidcnt; tididx++) {
 			u32 tidentry = flow->fstate->tid_entry[tididx], tidlen,
-			tidnpkts, npkts;
+				tidnpkts, npkts;
 
 			flow->tid_offset = 0;
 			tidlen = EXP_TID_GET(tidentry, LEN) * PAGE_SIZE;
@@ -2349,17 +4272,59 @@  void hfi1_tid_rdma_restart_req(struct rvt_qp *qp, struct rvt_swqe *wqe,
 				break;
 		}
 	}
+	if (wqe->wr.opcode == IB_WR_TID_RDMA_WRITE) {
+		rvt_skip_sge(&qpriv->tid_ss, (req->cur_seg * req->seg_len) +
+			     flow->sent, 0);
+		/*
+		 * Packet PSN is based on flow_state.spsn + flow->pkt. However,
+		 * during a RESYNC, the generation is incremented and the
+		 * sequence is reset to 0. Since we've adjusted the npkts in the
+		 * flow and the SGE has been sufficiently advanced, we have to
+		 * adjust flow->pkt in order to calculate the correct PSN.
+		 */
+		flow->pkt -= flow->resync_npkts;
+	}
 
 	if (flow->tid_offset ==
-		EXP_TID_GET(flow->fstate->tid_entry[tididx], LEN) * PAGE_SIZE) {
+	    EXP_TID_GET(flow->fstate->tid_entry[tididx], LEN) * PAGE_SIZE) {
 		tididx++;
 		flow->tid_offset = 0;
 	}
 	flow->tid_idx = tididx;
-	/* Move flow_idx to correct index */
-	req->flow_idx = fidx;
+	if (wqe->wr.opcode == IB_WR_TID_RDMA_READ)
+		/* Move flow_idx to correct index */
+		req->flow_idx = fidx;
+	else
+		req->clear_tail = fidx;
 
 	req->state = TID_REQUEST_ACTIVE;
+	if (wqe->wr.opcode == IB_WR_TID_RDMA_WRITE) {
+		/* Reset all the flows that we are going to resend */
+		fidx = CIRC_NEXT(fidx, req->n_max_flows);
+		i = qpriv->s_tid_tail;
+		do {
+			for (;
+			      CIRC_CNT(req->setup_head, fidx, req->n_max_flows);
+			      fidx = CIRC_NEXT(fidx, req->n_max_flows)) {
+				req->flows[fidx].sent = 0;
+				req->flows[fidx].pkt = 0;
+				req->flows[fidx].tid_idx = 0;
+				req->flows[fidx].tid_offset = 0;
+				req->flows[fidx].resync_npkts = 0;
+			}
+			if (i == qpriv->s_tid_cur)
+				break;
+			do {
+				i = (++i == qp->s_size ? 0 : i);
+				wqe = rvt_get_swqe_ptr(qp, i);
+			} while (wqe->wr.opcode != IB_WR_TID_RDMA_WRITE);
+			req = wqe_to_tid_req(wqe);
+			req->cur_seg = req->ack_seg;
+			fidx = req->acked_tail;
+			/* Pull req->clear_tail back */
+			req->clear_tail = fidx;
+		} while (1);
+	}
 }
 
 void _hfi1_do_tid_send(struct work_struct *work)
@@ -2442,7 +4407,36 @@  u32 hfi1_build_tid_rdma_write_req(struct rvt_qp *qp, struct rvt_swqe *wqe,
 				  struct ib_other_headers *ohdr,
 				  u32 *bth1, u32 *bth2, u32 *len)
 {
-	return 0;
+	struct hfi1_qp_priv *qpriv = qp->priv;
+	struct tid_rdma_request *req = wqe_to_tid_req(wqe);
+	struct tid_rdma_params *remote;
+
+	rcu_read_lock();
+	remote = rcu_dereference(qpriv->tid_rdma.remote);
+	/*
+	 * Set the number of flow to be used based on negotiated
+	 * parameters.
+	 */
+	req->n_flows = remote->max_write;
+	req->state = TID_REQUEST_ACTIVE;
+
+	KDETH_RESET(ohdr->u.tid_rdma.w_req.kdeth0, KVER, 0x1);
+	KDETH_RESET(ohdr->u.tid_rdma.w_req.kdeth1, JKEY, remote->jkey);
+	ohdr->u.tid_rdma.w_req.reth.vaddr =
+		cpu_to_be64(wqe->rdma_wr.remote_addr + (wqe->length - *len));
+	ohdr->u.tid_rdma.w_req.reth.rkey =
+		cpu_to_be32(wqe->rdma_wr.rkey);
+	ohdr->u.tid_rdma.w_req.reth.length = cpu_to_be32(*len);
+	ohdr->u.tid_rdma.w_req.verbs_qp = cpu_to_be32(qp->remote_qpn);
+	*bth1 &= ~RVT_QPN_MASK;
+	*bth1 |= remote->qp;
+	qp->s_state = TID_OP(WRITE_REQ);
+	qp->s_flags |= HFI1_S_WAIT_TID_RESP;
+	*bth2 |= IB_BTH_REQ_ACK;
+	*len = 0;
+
+	rcu_read_unlock();
+	return sizeof(ohdr->u.tid_rdma.w_req) / sizeof(u32);
 }
 
 u32 hfi1_build_tid_rdma_write_resp(struct rvt_qp *qp, struct rvt_ack_entry *e,
@@ -2450,7 +4444,97 @@  u32 hfi1_build_tid_rdma_write_resp(struct rvt_qp *qp, struct rvt_ack_entry *e,
 				   u32 bth2, u32 *len,
 				   struct rvt_sge_state **ss)
 {
-	return 0;
+	struct hfi1_ack_priv *epriv = e->priv;
+	struct tid_rdma_request *req = &epriv->tid_req;
+	struct hfi1_qp_priv *qpriv = qp->priv;
+	struct tid_rdma_flow *flow = NULL;
+	u32 resp_len = 0, hdwords = 0;
+	void *resp_addr = NULL;
+	struct tid_rdma_params *remote;
+
+	flow = &req->flows[req->flow_idx];
+	switch (req->state) {
+	default:
+		/*
+		 * Try to allocate resources here in case QP was queued and was
+		 * later scheduled when resources became available
+		 */
+		hfi1_tid_write_alloc_resources(qp, false);
+
+		/* We've already sent everything which is ready */
+		if (req->cur_seg >= req->alloc_seg)
+			goto done;
+
+		/*
+		 * Resources can be assigned but responses cannot be sent in
+		 * rnr_nak state, till the resent request is received
+		 */
+		if (qpriv->rnr_nak_state == TID_RNR_NAK_SENT)
+			goto done;
+
+		req->state = TID_REQUEST_ACTIVE;
+		req->flow_idx = CIRC_NEXT(req->flow_idx, req->n_max_flows);
+		hfi1_add_tid_reap_timer(qp);
+		break;
+
+	case TID_REQUEST_RESEND_ACTIVE:
+	case TID_REQUEST_RESEND:
+		req->flow_idx = CIRC_NEXT(req->flow_idx, req->n_max_flows);
+		if (!CIRC_CNT(req->setup_head, req->flow_idx,
+			      req->n_max_flows))
+			req->state = TID_REQUEST_ACTIVE;
+
+		hfi1_mod_tid_reap_timer(qp);
+		break;
+	}
+	flow->flow_state.resp_ib_psn = bth2;
+	resp_addr = (void *)flow->fstate->tid_entry;
+	resp_len = sizeof(*flow->fstate->tid_entry) * flow->tidcnt;
+	req->cur_seg++;
+
+	memset(&ohdr->u.tid_rdma.w_rsp, 0, sizeof(ohdr->u.tid_rdma.w_rsp));
+	epriv->ss.sge.vaddr = resp_addr;
+	epriv->ss.sge.sge_length = resp_len;
+	epriv->ss.sge.length = epriv->ss.sge.sge_length;
+	/*
+	 * We can safely zero these out. Since the first SGE covers the
+	 * entire packet, nothing else should even look at the MR.
+	 */
+	epriv->ss.sge.mr = NULL;
+	epriv->ss.sge.m = 0;
+	epriv->ss.sge.n = 0;
+
+	epriv->ss.sg_list = NULL;
+	epriv->ss.total_len = epriv->ss.sge.sge_length;
+	epriv->ss.num_sge = 1;
+
+	*ss = &epriv->ss;
+	*len = epriv->ss.total_len;
+
+	/* Construct the TID RDMA WRITE RESP packet header */
+	rcu_read_lock();
+	remote = rcu_dereference(qpriv->tid_rdma.remote);
+
+	KDETH_RESET(ohdr->u.tid_rdma.w_rsp.kdeth0, KVER, 0x1);
+	KDETH_RESET(ohdr->u.tid_rdma.w_rsp.kdeth1, JKEY, remote->jkey);
+	ohdr->u.tid_rdma.w_rsp.aeth = rvt_compute_aeth(qp);
+	ohdr->u.tid_rdma.w_rsp.tid_flow_psn =
+		cpu_to_be32((flow->flow_state.generation <<
+			     HFI1_KDETH_BTH_SEQ_SHIFT) |
+			    (flow->flow_state.spsn &
+			     HFI1_KDETH_BTH_SEQ_MASK));
+	ohdr->u.tid_rdma.w_rsp.tid_flow_qp =
+		cpu_to_be32(qpriv->tid_rdma.local.qp |
+			    ((flow->idx & TID_RDMA_DESTQP_FLOW_MASK) <<
+			     TID_RDMA_DESTQP_FLOW_SHIFT) |
+			    qpriv->rcd->ctxt);
+	ohdr->u.tid_rdma.w_rsp.verbs_qp = cpu_to_be32(qp->remote_qpn);
+	*bth1 = remote->qp;
+	rcu_read_unlock();
+	hdwords = sizeof(ohdr->u.tid_rdma.w_rsp) / sizeof(u32);
+	qpriv->pending_tid_w_segs++;
+done:
+	return hdwords;
 }
 
 u32 hfi1_build_tid_rdma_read_packet(struct rvt_swqe *wqe,
@@ -2539,7 +4623,7 @@  u32 hfi1_build_tid_rdma_read_packet(struct rvt_swqe *wqe,
 u32 hfi1_build_tid_rdma_read_req(struct rvt_qp *qp, struct rvt_swqe *wqe,
 				 struct ib_other_headers *ohdr, u32 *bth1,
 				 u32 *bth2, u32 *len)
-	 __must_hold(&qp->s_lock)
+	__must_hold(&qp->s_lock)
 {
 	struct hfi1_qp_priv *qpriv = qp->priv;
 	struct tid_rdma_request *req = wqe_to_tid_req(wqe);
diff --git a/drivers/infiniband/hw/hfi1/verbs.h b/drivers/infiniband/hw/hfi1/verbs.h
index 6d11e5c..8ef9ae6 100644
--- a/drivers/infiniband/hw/hfi1/verbs.h
+++ b/drivers/infiniband/hw/hfi1/verbs.h
@@ -182,6 +182,7 @@  struct hfi1_qp_priv {
 	u8 s_state;
 	u8 s_nak_state;
 	u8 s_retry;
+	u32 s_nak_psn;
 	u32 s_flags;
 	u32 s_tid_cur;
 	u32 s_tid_head;
@@ -203,6 +204,8 @@  struct hfi1_qp_priv {
 	u8 rnr_nak_state;       /* RNR NAK state */
 	u32 r_next_psn_ib;
 	u32 r_next_psn_kdeth;
+	u32 r_next_psn_kdeth_save;
+	u32 s_resync_psn;
 	bool sync_pt;           /* Set when QP reaches sync point */
 	bool resync;
 };