Adding upstream version 6.6.15.upstream/6.6.15

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

1 files changed, 5532 insertions, 0 deletions

diff --git a/drivers/infiniband/hw/hfi1/tid_rdma.c b/drivers/infiniband/hw/hfi1/tid_rdma.c
new file mode 100644
index 0000000000..18b05ffb41
--- /dev/null
+++ b/drivers/infiniband/hw/hfi1/tid_rdma.c
@@ -0,0 +1,5532 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+/*
+ * Copyright(c) 2018 - 2020 Intel Corporation.
+ *
+ */
+
+#include "hfi.h"
+#include "qp.h"
+#include "rc.h"
+#include "verbs.h"
+#include "tid_rdma.h"
+#include "exp_rcv.h"
+#include "trace.h"
+
+/**
+ * DOC: TID RDMA READ protocol
+ *
+ * This is an end-to-end protocol at the hfi1 level between two nodes that
+ * improves performance by avoiding data copy on the requester side. It
+ * converts a qualified RDMA READ request into a TID RDMA READ request on
+ * the requester side and thereafter handles the request and response
+ * differently. To be qualified, the RDMA READ request should meet the
+ * following:
+ * -- The total data length should be greater than 256K;
+ * -- The total data length should be a multiple of 4K page size;
+ * -- Each local scatter-gather entry should be 4K page aligned;
+ * -- Each local scatter-gather entry should be a multiple of 4K page size;
+ */
+
+#define RCV_TID_FLOW_TABLE_CTRL_FLOW_VALID_SMASK BIT_ULL(32)
+#define RCV_TID_FLOW_TABLE_CTRL_HDR_SUPP_EN_SMASK BIT_ULL(33)
+#define RCV_TID_FLOW_TABLE_CTRL_KEEP_AFTER_SEQ_ERR_SMASK BIT_ULL(34)
+#define RCV_TID_FLOW_TABLE_CTRL_KEEP_ON_GEN_ERR_SMASK BIT_ULL(35)
+#define RCV_TID_FLOW_TABLE_STATUS_SEQ_MISMATCH_SMASK BIT_ULL(37)
+#define RCV_TID_FLOW_TABLE_STATUS_GEN_MISMATCH_SMASK BIT_ULL(38)
+
+/* Maximum number of packets within a flow generation. */
+#define MAX_TID_FLOW_PSN BIT(HFI1_KDETH_BTH_SEQ_SHIFT)
+
+#define GENERATION_MASK 0xFFFFF
+
+static u32 mask_generation(u32 a)
+{
+	return a & GENERATION_MASK;
+}
+
+/* Reserved generation value to set to unused flows for kernel contexts */
+#define KERN_GENERATION_RESERVED mask_generation(U32_MAX)
+
+/*
+ * J_KEY for kernel contexts when TID RDMA is used.
+ * See generate_jkey() in hfi.h for more information.
+ */
+#define TID_RDMA_JKEY                   32
+#define HFI1_KERNEL_MIN_JKEY HFI1_ADMIN_JKEY_RANGE
+#define HFI1_KERNEL_MAX_JKEY (2 * HFI1_ADMIN_JKEY_RANGE - 1)
+
+/* Maximum number of segments in flight per QP request. */
+#define TID_RDMA_MAX_READ_SEGS_PER_REQ  6
+#define TID_RDMA_MAX_WRITE_SEGS_PER_REQ 4
+#define MAX_REQ max_t(u16, TID_RDMA_MAX_READ_SEGS_PER_REQ, \
+			TID_RDMA_MAX_WRITE_SEGS_PER_REQ)
+#define MAX_FLOWS roundup_pow_of_two(MAX_REQ + 1)
+
+#define MAX_EXPECTED_PAGES     (MAX_EXPECTED_BUFFER / PAGE_SIZE)
+
+#define TID_RDMA_DESTQP_FLOW_SHIFT      11
+#define TID_RDMA_DESTQP_FLOW_MASK       0x1f
+
+#define TID_OPFN_QP_CTXT_MASK 0xff
+#define TID_OPFN_QP_CTXT_SHIFT 56
+#define TID_OPFN_QP_KDETH_MASK 0xff
+#define TID_OPFN_QP_KDETH_SHIFT 48
+#define TID_OPFN_MAX_LEN_MASK 0x7ff
+#define TID_OPFN_MAX_LEN_SHIFT 37
+#define TID_OPFN_TIMEOUT_MASK 0x1f
+#define TID_OPFN_TIMEOUT_SHIFT 32
+#define TID_OPFN_RESERVED_MASK 0x3f
+#define TID_OPFN_RESERVED_SHIFT 26
+#define TID_OPFN_URG_MASK 0x1
+#define TID_OPFN_URG_SHIFT 25
+#define TID_OPFN_VER_MASK 0x7
+#define TID_OPFN_VER_SHIFT 22
+#define TID_OPFN_JKEY_MASK 0x3f
+#define TID_OPFN_JKEY_SHIFT 16
+#define TID_OPFN_MAX_READ_MASK 0x3f
+#define TID_OPFN_MAX_READ_SHIFT 10
+#define TID_OPFN_MAX_WRITE_MASK 0x3f
+#define TID_OPFN_MAX_WRITE_SHIFT 4
+
+/*
+ * OPFN TID layout
+ *
+ * 63               47               31               15
+ * NNNNNNNNKKKKKKKK MMMMMMMMMMMTTTTT DDDDDDUVVVJJJJJJ RRRRRRWWWWWWCCCC
+ * 3210987654321098 7654321098765432 1098765432109876 5432109876543210
+ * N - the context Number
+ * K - the Kdeth_qp
+ * M - Max_len
+ * T - Timeout
+ * D - reserveD
+ * V - version
+ * U - Urg capable
+ * J - Jkey
+ * R - max_Read
+ * W - max_Write
+ * C - Capcode
+ */
+
+static void tid_rdma_trigger_resume(struct work_struct *work);
+static void hfi1_kern_exp_rcv_free_flows(struct tid_rdma_request *req);
+static int hfi1_kern_exp_rcv_alloc_flows(struct tid_rdma_request *req,
+					 gfp_t gfp);
+static void hfi1_init_trdma_req(struct rvt_qp *qp,
+				struct tid_rdma_request *req);
+static void hfi1_tid_write_alloc_resources(struct rvt_qp *qp, bool intr_ctx);
+static void hfi1_tid_timeout(struct timer_list *t);
+static void hfi1_add_tid_reap_timer(struct rvt_qp *qp);
+static void hfi1_mod_tid_reap_timer(struct rvt_qp *qp);
+static void hfi1_mod_tid_retry_timer(struct rvt_qp *qp);
+static int hfi1_stop_tid_retry_timer(struct rvt_qp *qp);
+static void hfi1_tid_retry_timeout(struct timer_list *t);
+static int make_tid_rdma_ack(struct rvt_qp *qp,
+			     struct ib_other_headers *ohdr,
+			     struct hfi1_pkt_state *ps);
+static void hfi1_do_tid_send(struct rvt_qp *qp);
+static u32 read_r_next_psn(struct hfi1_devdata *dd, u8 ctxt, u8 fidx);
+static void tid_rdma_rcv_err(struct hfi1_packet *packet,
+			     struct ib_other_headers *ohdr,
+			     struct rvt_qp *qp, u32 psn, int diff, bool fecn);
+static void update_r_next_psn_fecn(struct hfi1_packet *packet,
+				   struct hfi1_qp_priv *priv,
+				   struct hfi1_ctxtdata *rcd,
+				   struct tid_rdma_flow *flow,
+				   bool fecn);
+
+static void validate_r_tid_ack(struct hfi1_qp_priv *priv)
+{
+	if (priv->r_tid_ack == HFI1_QP_WQE_INVALID)
+		priv->r_tid_ack = priv->r_tid_tail;
+}
+
+static void tid_rdma_schedule_ack(struct rvt_qp *qp)
+{
+	struct hfi1_qp_priv *priv = qp->priv;
+
+	priv->s_flags |= RVT_S_ACK_PENDING;
+	hfi1_schedule_tid_send(qp);
+}
+
+static void tid_rdma_trigger_ack(struct rvt_qp *qp)
+{
+	validate_r_tid_ack(qp->priv);
+	tid_rdma_schedule_ack(qp);
+}
+
+static u64 tid_rdma_opfn_encode(struct tid_rdma_params *p)
+{
+	return
+		(((u64)p->qp & TID_OPFN_QP_CTXT_MASK) <<
+			TID_OPFN_QP_CTXT_SHIFT) |
+		((((u64)p->qp >> 16) & TID_OPFN_QP_KDETH_MASK) <<
+			TID_OPFN_QP_KDETH_SHIFT) |
+		(((u64)((p->max_len >> PAGE_SHIFT) - 1) &
+			TID_OPFN_MAX_LEN_MASK) << TID_OPFN_MAX_LEN_SHIFT) |
+		(((u64)p->timeout & TID_OPFN_TIMEOUT_MASK) <<
+			TID_OPFN_TIMEOUT_SHIFT) |
+		(((u64)p->urg & TID_OPFN_URG_MASK) << TID_OPFN_URG_SHIFT) |
+		(((u64)p->jkey & TID_OPFN_JKEY_MASK) << TID_OPFN_JKEY_SHIFT) |
+		(((u64)p->max_read & TID_OPFN_MAX_READ_MASK) <<
+			TID_OPFN_MAX_READ_SHIFT) |
+		(((u64)p->max_write & TID_OPFN_MAX_WRITE_MASK) <<
+			TID_OPFN_MAX_WRITE_SHIFT);
+}
+
+static void tid_rdma_opfn_decode(struct tid_rdma_params *p, u64 data)
+{
+	p->max_len = (((data >> TID_OPFN_MAX_LEN_SHIFT) &
+		TID_OPFN_MAX_LEN_MASK) + 1) << PAGE_SHIFT;
+	p->jkey = (data >> TID_OPFN_JKEY_SHIFT) & TID_OPFN_JKEY_MASK;
+	p->max_write = (data >> TID_OPFN_MAX_WRITE_SHIFT) &
+		TID_OPFN_MAX_WRITE_MASK;
+	p->max_read = (data >> TID_OPFN_MAX_READ_SHIFT) &
+		TID_OPFN_MAX_READ_MASK;
+	p->qp =
+		((((data >> TID_OPFN_QP_KDETH_SHIFT) & TID_OPFN_QP_KDETH_MASK)
+			<< 16) |
+		((data >> TID_OPFN_QP_CTXT_SHIFT) & TID_OPFN_QP_CTXT_MASK));
+	p->urg = (data >> TID_OPFN_URG_SHIFT) & TID_OPFN_URG_MASK;
+	p->timeout = (data >> TID_OPFN_TIMEOUT_SHIFT) & TID_OPFN_TIMEOUT_MASK;
+}
+
+void tid_rdma_opfn_init(struct rvt_qp *qp, struct tid_rdma_params *p)
+{
+	struct hfi1_qp_priv *priv = qp->priv;
+
+	p->qp = (RVT_KDETH_QP_PREFIX << 16) | priv->rcd->ctxt;
+	p->max_len = TID_RDMA_MAX_SEGMENT_SIZE;
+	p->jkey = priv->rcd->jkey;
+	p->max_read = TID_RDMA_MAX_READ_SEGS_PER_REQ;
+	p->max_write = TID_RDMA_MAX_WRITE_SEGS_PER_REQ;
+	p->timeout = qp->timeout;
+	p->urg = is_urg_masked(priv->rcd);
+}
+
+bool tid_rdma_conn_req(struct rvt_qp *qp, u64 *data)
+{
+	struct hfi1_qp_priv *priv = qp->priv;
+
+	*data = tid_rdma_opfn_encode(&priv->tid_rdma.local);
+	return true;
+}
+
+bool tid_rdma_conn_reply(struct rvt_qp *qp, u64 data)
+{
+	struct hfi1_qp_priv *priv = qp->priv;
+	struct tid_rdma_params *remote, *old;
+	bool ret = true;
+
+	old = rcu_dereference_protected(priv->tid_rdma.remote,
+					lockdep_is_held(&priv->opfn.lock));
+	data &= ~0xfULL;
+	/*
+	 * If data passed in is zero, return true so as not to continue the
+	 * negotiation process
+	 */
+	if (!data || !HFI1_CAP_IS_KSET(TID_RDMA))
+		goto null;
+	/*
+	 * If kzalloc fails, return false. This will result in:
+	 * * at the requester a new OPFN request being generated to retry
+	 *   the negotiation
+	 * * at the responder, 0 being returned to the requester so as to
+	 *   disable TID RDMA at both the requester and the responder
+	 */
+	remote = kzalloc(sizeof(*remote), GFP_ATOMIC);
+	if (!remote) {
+		ret = false;
+		goto null;
+	}
+
+	tid_rdma_opfn_decode(remote, data);
+	priv->tid_timer_timeout_jiffies =
+		usecs_to_jiffies((((4096UL * (1UL << remote->timeout)) /
+				   1000UL) << 3) * 7);
+	trace_hfi1_opfn_param(qp, 0, &priv->tid_rdma.local);
+	trace_hfi1_opfn_param(qp, 1, remote);
+	rcu_assign_pointer(priv->tid_rdma.remote, remote);
+	/*
+	 * A TID RDMA READ request's segment size is not equal to
+	 * remote->max_len only when the request's data length is smaller
+	 * than remote->max_len. In that case, there will be only one segment.
+	 * Therefore, when priv->pkts_ps is used to calculate req->cur_seg
+	 * during retry, it will lead to req->cur_seg = 0, which is exactly
+	 * what is expected.
+	 */
+	priv->pkts_ps = (u16)rvt_div_mtu(qp, remote->max_len);
+	priv->timeout_shift = ilog2(priv->pkts_ps - 1) + 1;
+	goto free;
+null:
+	RCU_INIT_POINTER(priv->tid_rdma.remote, NULL);
+	priv->timeout_shift = 0;
+free:
+	if (old)
+		kfree_rcu(old, rcu_head);
+	return ret;
+}
+
+bool tid_rdma_conn_resp(struct rvt_qp *qp, u64 *data)
+{
+	bool ret;
+
+	ret = tid_rdma_conn_reply(qp, *data);
+	*data = 0;
+	/*
+	 * If tid_rdma_conn_reply() returns error, set *data as 0 to indicate
+	 * TID RDMA could not be enabled. This will result in TID RDMA being
+	 * disabled at the requester too.
+	 */
+	if (ret)
+		(void)tid_rdma_conn_req(qp, data);
+	return ret;
+}
+
+void tid_rdma_conn_error(struct rvt_qp *qp)
+{
+	struct hfi1_qp_priv *priv = qp->priv;
+	struct tid_rdma_params *old;
+
+	old = rcu_dereference_protected(priv->tid_rdma.remote,
+					lockdep_is_held(&priv->opfn.lock));
+	RCU_INIT_POINTER(priv->tid_rdma.remote, NULL);
+	if (old)
+		kfree_rcu(old, rcu_head);
+}
+
+/* This is called at context initialization time */
+int hfi1_kern_exp_rcv_init(struct hfi1_ctxtdata *rcd, int reinit)
+{
+	if (reinit)
+		return 0;
+
+	BUILD_BUG_ON(TID_RDMA_JKEY < HFI1_KERNEL_MIN_JKEY);
+	BUILD_BUG_ON(TID_RDMA_JKEY > HFI1_KERNEL_MAX_JKEY);
+	rcd->jkey = TID_RDMA_JKEY;
+	hfi1_set_ctxt_jkey(rcd->dd, rcd, rcd->jkey);
+	return hfi1_alloc_ctxt_rcv_groups(rcd);
+}
+
+/**
+ * qp_to_rcd - determine the receive context used by a qp
+ * @rdi: rvt dev struct
+ * @qp: the qp
+ *
+ * This routine returns the receive context associated
+ * with a a qp's qpn.
+ *
+ * Returns the context.
+ */
+static struct hfi1_ctxtdata *qp_to_rcd(struct rvt_dev_info *rdi,
+				       struct rvt_qp *qp)
+{
+	struct hfi1_ibdev *verbs_dev = container_of(rdi,
+						    struct hfi1_ibdev,
+						    rdi);
+	struct hfi1_devdata *dd = container_of(verbs_dev,
+					       struct hfi1_devdata,
+					       verbs_dev);
+	unsigned int ctxt;
+
+	if (qp->ibqp.qp_num == 0)
+		ctxt = 0;
+	else
+		ctxt = hfi1_get_qp_map(dd, qp->ibqp.qp_num >> dd->qos_shift);
+	return dd->rcd[ctxt];
+}
+
+int hfi1_qp_priv_init(struct rvt_dev_info *rdi, struct rvt_qp *qp,
+		      struct ib_qp_init_attr *init_attr)
+{
+	struct hfi1_qp_priv *qpriv = qp->priv;
+	int i, ret;
+
+	qpriv->rcd = qp_to_rcd(rdi, 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->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_head = HFI1_QP_WQE_INVALID;
+	qpriv->s_tid_tail = HFI1_QP_WQE_INVALID;
+	qpriv->rnr_nak_state = TID_RNR_NAK_INIT;
+	qpriv->r_tid_head = HFI1_QP_WQE_INVALID;
+	qpriv->r_tid_tail = HFI1_QP_WQE_INVALID;
+	qpriv->r_tid_ack = HFI1_QP_WQE_INVALID;
+	qpriv->r_tid_alloc = 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;
+
+		qpriv->pages = kzalloc_node(TID_RDMA_MAX_PAGES *
+						sizeof(*qpriv->pages),
+					    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);
+
+			priv = kzalloc_node(sizeof(*priv), GFP_KERNEL,
+					    dd->node);
+			if (!priv)
+				return -ENOMEM;
+
+			hfi1_init_trdma_req(qp, &priv->tid_req);
+			priv->tid_req.e.swqe = wqe;
+			wqe->priv = priv;
+		}
+		for (i = 0; i < rvt_max_atomic(rdi); i++) {
+			struct hfi1_ack_priv *priv;
+
+			priv = kzalloc_node(sizeof(*priv), GFP_KERNEL,
+					    dd->node);
+			if (!priv)
+				return -ENOMEM;
+
+			hfi1_init_trdma_req(qp, &priv->tid_req);
+			priv->tid_req.e.ack = &qp->s_ack_queue[i];
+
+			ret = hfi1_kern_exp_rcv_alloc_flows(&priv->tid_req,
+							    GFP_KERNEL);
+			if (ret) {
+				kfree(priv);
+				return ret;
+			}
+			qp->s_ack_queue[i].priv = priv;
+		}
+	}
+
+	return 0;
+}
+
+void hfi1_qp_priv_tid_free(struct rvt_dev_info *rdi, struct rvt_qp *qp)
+{
+	struct hfi1_qp_priv *qpriv = qp->priv;
+	struct rvt_swqe *wqe;
+	u32 i;
+
+	if (qp->ibqp.qp_type == IB_QPT_RC && HFI1_CAP_IS_KSET(TID_RDMA)) {
+		for (i = 0; i < qp->s_size; i++) {
+			wqe = rvt_get_swqe_ptr(qp, i);
+			kfree(wqe->priv);
+			wqe->priv = NULL;
+		}
+		for (i = 0; i < rvt_max_atomic(rdi); i++) {
+			struct hfi1_ack_priv *priv = qp->s_ack_queue[i].priv;
+
+			if (priv)
+				hfi1_kern_exp_rcv_free_flows(&priv->tid_req);
+			kfree(priv);
+			qp->s_ack_queue[i].priv = NULL;
+		}
+		cancel_work_sync(&qpriv->opfn.opfn_work);
+		kfree(qpriv->pages);
+		qpriv->pages = NULL;
+	}
+}
+
+/* Flow and tid waiter functions */
+/**
+ * DOC: lock ordering
+ *
+ * There are two locks involved with the queuing
+ * routines: the qp s_lock and the exp_lock.
+ *
+ * Since the tid space allocation is called from
+ * the send engine, the qp s_lock is already held.
+ *
+ * The allocation routines will get the exp_lock.
+ *
+ * The first_qp() call is provided to allow the head of
+ * the rcd wait queue to be fetched under the exp_lock and
+ * followed by a drop of the exp_lock.
+ *
+ * Any qp in the wait list will have the qp reference count held
+ * to hold the qp in memory.
+ */
+
+/*
+ * return head of rcd wait list
+ *
+ * Must hold the exp_lock.
+ *
+ * Get a reference to the QP to hold the QP in memory.
+ *
+ * The caller must release the reference when the local
+ * is no longer being used.
+ */
+static struct rvt_qp *first_qp(struct hfi1_ctxtdata *rcd,
+			       struct tid_queue *queue)
+	__must_hold(&rcd->exp_lock)
+{
+	struct hfi1_qp_priv *priv;
+
+	lockdep_assert_held(&rcd->exp_lock);
+	priv = list_first_entry_or_null(&queue->queue_head,
+					struct hfi1_qp_priv,
+					tid_wait);
+	if (!priv)
+		return NULL;
+	rvt_get_qp(priv->owner);
+	return priv->owner;
+}
+
+/**
+ * kernel_tid_waiters - determine rcd wait
+ * @rcd: the receive context
+ * @queue: the queue to operate on
+ * @qp: the head of the qp being processed
+ *
+ * This routine will return false IFF
+ * the list is NULL or the head of the
+ * list is the indicated qp.
+ *
+ * Must hold the qp s_lock and the exp_lock.
+ *
+ * Return:
+ * false if either of the conditions below are satisfied:
+ * 1. The list is empty or
+ * 2. The indicated qp is at the head of the list and the
+ *    HFI1_S_WAIT_TID_SPACE bit is set in qp->s_flags.
+ * true is returned otherwise.
+ */
+static bool kernel_tid_waiters(struct hfi1_ctxtdata *rcd,
+			       struct tid_queue *queue, struct rvt_qp *qp)
+	__must_hold(&rcd->exp_lock) __must_hold(&qp->s_lock)
+{
+	struct rvt_qp *fqp;
+	bool ret = true;
+
+	lockdep_assert_held(&qp->s_lock);
+	lockdep_assert_held(&rcd->exp_lock);
+	fqp = first_qp(rcd, queue);
+	if (!fqp || (fqp == qp && (qp->s_flags & HFI1_S_WAIT_TID_SPACE)))
+		ret = false;
+	rvt_put_qp(fqp);
+	return ret;
+}
+
+/**
+ * dequeue_tid_waiter - dequeue the qp from the list
+ * @rcd: the receive context
+ * @queue: the queue to operate on
+ * @qp: the qp to remove the wait list
+ *
+ * This routine removes the indicated qp from the
+ * wait list if it is there.
+ *
+ * This should be done after the hardware flow and
+ * tid array resources have been allocated.
+ *
+ * Must hold the qp s_lock and the rcd exp_lock.
+ *
+ * It assumes the s_lock to protect the s_flags
+ * field and to reliably test the HFI1_S_WAIT_TID_SPACE flag.
+ */
+static void dequeue_tid_waiter(struct hfi1_ctxtdata *rcd,
+			       struct tid_queue *queue, struct rvt_qp *qp)
+	__must_hold(&rcd->exp_lock) __must_hold(&qp->s_lock)
+{
+	struct hfi1_qp_priv *priv = qp->priv;
+
+	lockdep_assert_held(&qp->s_lock);
+	lockdep_assert_held(&rcd->exp_lock);
+	if (list_empty(&priv->tid_wait))
+		return;
+	list_del_init(&priv->tid_wait);
+	qp->s_flags &= ~HFI1_S_WAIT_TID_SPACE;
+	queue->dequeue++;
+	rvt_put_qp(qp);
+}
+
+/**
+ * queue_qp_for_tid_wait - suspend QP on tid space
+ * @rcd: the receive context
+ * @queue: the queue to operate on
+ * @qp: the qp
+ *
+ * The qp is inserted at the tail of the rcd
+ * wait queue and the HFI1_S_WAIT_TID_SPACE s_flag is set.
+ *
+ * Must hold the qp s_lock and the exp_lock.
+ */
+static void queue_qp_for_tid_wait(struct hfi1_ctxtdata *rcd,
+				  struct tid_queue *queue, struct rvt_qp *qp)
+	__must_hold(&rcd->exp_lock) __must_hold(&qp->s_lock)
+{
+	struct hfi1_qp_priv *priv = qp->priv;
+
+	lockdep_assert_held(&qp->s_lock);
+	lockdep_assert_held(&rcd->exp_lock);
+	if (list_empty(&priv->tid_wait)) {
+		qp->s_flags |= HFI1_S_WAIT_TID_SPACE;
+		list_add_tail(&priv->tid_wait, &queue->queue_head);
+		priv->tid_enqueue = ++queue->enqueue;
+		rcd->dd->verbs_dev.n_tidwait++;
+		trace_hfi1_qpsleep(qp, HFI1_S_WAIT_TID_SPACE);
+		rvt_get_qp(qp);
+	}
+}
+
+/**
+ * __trigger_tid_waiter - trigger tid waiter
+ * @qp: the qp
+ *
+ * This is a private entrance to schedule the qp
+ * assuming the caller is holding the qp->s_lock.
+ */
+static void __trigger_tid_waiter(struct rvt_qp *qp)
+	__must_hold(&qp->s_lock)
+{
+	lockdep_assert_held(&qp->s_lock);
+	if (!(qp->s_flags & HFI1_S_WAIT_TID_SPACE))
+		return;
+	trace_hfi1_qpwakeup(qp, HFI1_S_WAIT_TID_SPACE);
+	hfi1_schedule_send(qp);
+}
+
+/**
+ * tid_rdma_schedule_tid_wakeup - schedule wakeup for a qp
+ * @qp: the qp
+ *
+ * trigger a schedule or a waiting qp in a deadlock
+ * safe manner.  The qp reference is held prior
+ * to this call via first_qp().
+ *
+ * If the qp trigger was already scheduled (!rval)
+ * the reference is dropped, otherwise the resume
+ * or the destroy cancel will dispatch the reference.
+ */
+static void tid_rdma_schedule_tid_wakeup(struct rvt_qp *qp)
+{
+	struct hfi1_qp_priv *priv;
+	struct hfi1_ibport *ibp;
+	struct hfi1_pportdata *ppd;
+	struct hfi1_devdata *dd;
+	bool rval;
+
+	if (!qp)
+		return;
+
+	priv = qp->priv;
+	ibp = to_iport(qp->ibqp.device, qp->port_num);
+	ppd = ppd_from_ibp(ibp);
+	dd = dd_from_ibdev(qp->ibqp.device);
+
+	rval = queue_work_on(priv->s_sde ?
+			     priv->s_sde->cpu :
+			     cpumask_first(cpumask_of_node(dd->node)),
+			     ppd->hfi1_wq,
+			     &priv->tid_rdma.trigger_work);
+	if (!rval)
+		rvt_put_qp(qp);
+}
+
+/**
+ * tid_rdma_trigger_resume - field a trigger work request
+ * @work: the work item
+ *
+ * Complete the off qp trigger processing by directly
+ * calling the progress routine.
+ */
+static void tid_rdma_trigger_resume(struct work_struct *work)
+{
+	struct tid_rdma_qp_params *tr;
+	struct hfi1_qp_priv *priv;
+	struct rvt_qp *qp;
+
+	tr = container_of(work, struct tid_rdma_qp_params, trigger_work);
+	priv = container_of(tr, struct hfi1_qp_priv, tid_rdma);
+	qp = priv->owner;
+	spin_lock_irq(&qp->s_lock);
+	if (qp->s_flags & HFI1_S_WAIT_TID_SPACE) {
+		spin_unlock_irq(&qp->s_lock);
+		hfi1_do_send(priv->owner, true);
+	} else {
+		spin_unlock_irq(&qp->s_lock);
+	}
+	rvt_put_qp(qp);
+}
+
+/*
+ * tid_rdma_flush_wait - unwind any tid space wait
+ *
+ * This is called when resetting a qp to
+ * allow a destroy or reset to get rid
+ * of any tid space linkage and reference counts.
+ */
+static void _tid_rdma_flush_wait(struct rvt_qp *qp, struct tid_queue *queue)
+	__must_hold(&qp->s_lock)
+{
+	struct hfi1_qp_priv *priv;
+
+	if (!qp)
+		return;
+	lockdep_assert_held(&qp->s_lock);
+	priv = qp->priv;
+	qp->s_flags &= ~HFI1_S_WAIT_TID_SPACE;
+	spin_lock(&priv->rcd->exp_lock);
+	if (!list_empty(&priv->tid_wait)) {
+		list_del_init(&priv->tid_wait);
+		qp->s_flags &= ~HFI1_S_WAIT_TID_SPACE;
+		queue->dequeue++;
+		rvt_put_qp(qp);
+	}
+	spin_unlock(&priv->rcd->exp_lock);
+}
+
+void hfi1_tid_rdma_flush_wait(struct rvt_qp *qp)
+	__must_hold(&qp->s_lock)
+{
+	struct hfi1_qp_priv *priv = qp->priv;
+
+	_tid_rdma_flush_wait(qp, &priv->rcd->flow_queue);
+	_tid_rdma_flush_wait(qp, &priv->rcd->rarr_queue);
+}
+
+/* Flow functions */
+/**
+ * kern_reserve_flow - allocate a hardware flow
+ * @rcd: the context to use for allocation
+ * @last: the index of the preferred flow. Use RXE_NUM_TID_FLOWS to
+ *         signify "don't care".
+ *
+ * Use a bit mask based allocation to reserve a hardware
+ * flow for use in receiving KDETH data packets. If a preferred flow is
+ * specified the function will attempt to reserve that flow again, if
+ * available.
+ *
+ * The exp_lock must be held.
+ *
+ * Return:
+ * On success: a value postive value between 0 and RXE_NUM_TID_FLOWS - 1
+ * On failure: -EAGAIN
+ */
+static int kern_reserve_flow(struct hfi1_ctxtdata *rcd, int last)
+	__must_hold(&rcd->exp_lock)
+{
+	int nr;
+
+	/* Attempt to reserve the preferred flow index */
+	if (last >= 0 && last < RXE_NUM_TID_FLOWS &&
+	    !test_and_set_bit(last, &rcd->flow_mask))
+		return last;
+
+	nr = ffz(rcd->flow_mask);
+	BUILD_BUG_ON(RXE_NUM_TID_FLOWS >=
+		     (sizeof(rcd->flow_mask) * BITS_PER_BYTE));
+	if (nr > (RXE_NUM_TID_FLOWS - 1))
+		return -EAGAIN;
+	set_bit(nr, &rcd->flow_mask);
+	return nr;
+}
+
+static void kern_set_hw_flow(struct hfi1_ctxtdata *rcd, u32 generation,
+			     u32 flow_idx)
+{
+	u64 reg;
+
+	reg = ((u64)generation << HFI1_KDETH_BTH_SEQ_SHIFT) |
+		RCV_TID_FLOW_TABLE_CTRL_FLOW_VALID_SMASK |
+		RCV_TID_FLOW_TABLE_CTRL_KEEP_AFTER_SEQ_ERR_SMASK |
+		RCV_TID_FLOW_TABLE_CTRL_KEEP_ON_GEN_ERR_SMASK |
+		RCV_TID_FLOW_TABLE_STATUS_SEQ_MISMATCH_SMASK |
+		RCV_TID_FLOW_TABLE_STATUS_GEN_MISMATCH_SMASK;
+
+	if (generation != KERN_GENERATION_RESERVED)
+		reg |= RCV_TID_FLOW_TABLE_CTRL_HDR_SUPP_EN_SMASK;
+
+	write_uctxt_csr(rcd->dd, rcd->ctxt,
+			RCV_TID_FLOW_TABLE + 8 * flow_idx, reg);
+}
+
+static u32 kern_setup_hw_flow(struct hfi1_ctxtdata *rcd, u32 flow_idx)
+	__must_hold(&rcd->exp_lock)
+{
+	u32 generation = rcd->flows[flow_idx].generation;
+
+	kern_set_hw_flow(rcd, generation, flow_idx);
+	return generation;
+}
+
+static u32 kern_flow_generation_next(u32 gen)
+{
+	u32 generation = mask_generation(gen + 1);
+
+	if (generation == KERN_GENERATION_RESERVED)
+		generation = mask_generation(generation + 1);
+	return generation;
+}
+
+static void kern_clear_hw_flow(struct hfi1_ctxtdata *rcd, u32 flow_idx)
+	__must_hold(&rcd->exp_lock)
+{
+	rcd->flows[flow_idx].generation =
+		kern_flow_generation_next(rcd->flows[flow_idx].generation);
+	kern_set_hw_flow(rcd, KERN_GENERATION_RESERVED, flow_idx);
+}
+
+int hfi1_kern_setup_hw_flow(struct hfi1_ctxtdata *rcd, struct rvt_qp *qp)
+{
+	struct hfi1_qp_priv *qpriv = (struct hfi1_qp_priv *)qp->priv;
+	struct tid_flow_state *fs = &qpriv->flow_state;
+	struct rvt_qp *fqp;
+	unsigned long flags;
+	int ret = 0;
+
+	/* The QP already has an allocated flow */
+	if (fs->index != RXE_NUM_TID_FLOWS)
+		return ret;
+
+	spin_lock_irqsave(&rcd->exp_lock, flags);
+	if (kernel_tid_waiters(rcd, &rcd->flow_queue, qp))
+		goto queue;
+
+	ret = kern_reserve_flow(rcd, fs->last_index);
+	if (ret < 0)
+		goto queue;
+	fs->index = ret;
+	fs->last_index = fs->index;
+
+	/* Generation received in a RESYNC overrides default flow generation */
+	if (fs->generation != KERN_GENERATION_RESERVED)
+		rcd->flows[fs->index].generation = fs->generation;
+	fs->generation = kern_setup_hw_flow(rcd, fs->index);
+	fs->psn = 0;
+	dequeue_tid_waiter(rcd, &rcd->flow_queue, qp);
+	/* get head before dropping lock */
+	fqp = first_qp(rcd, &rcd->flow_queue);
+	spin_unlock_irqrestore(&rcd->exp_lock, flags);
+
+	tid_rdma_schedule_tid_wakeup(fqp);
+	return 0;
+queue:
+	queue_qp_for_tid_wait(rcd, &rcd->flow_queue, qp);
+	spin_unlock_irqrestore(&rcd->exp_lock, flags);
+	return -EAGAIN;
+}
+
+void hfi1_kern_clear_hw_flow(struct hfi1_ctxtdata *rcd, struct rvt_qp *qp)
+{
+	struct hfi1_qp_priv *qpriv = (struct hfi1_qp_priv *)qp->priv;
+	struct tid_flow_state *fs = &qpriv->flow_state;
+	struct rvt_qp *fqp;
+	unsigned long flags;
+
+	if (fs->index >= RXE_NUM_TID_FLOWS)
+		return;
+	spin_lock_irqsave(&rcd->exp_lock, flags);
+	kern_clear_hw_flow(rcd, fs->index);
+	clear_bit(fs->index, &rcd->flow_mask);
+	fs->index = RXE_NUM_TID_FLOWS;
+	fs->psn = 0;
+	fs->generation = KERN_GENERATION_RESERVED;
+
+	/* get head before dropping lock */
+	fqp = first_qp(rcd, &rcd->flow_queue);
+	spin_unlock_irqrestore(&rcd->exp_lock, flags);
+
+	if (fqp == qp) {
+		__trigger_tid_waiter(fqp);
+		rvt_put_qp(fqp);
+	} else {
+		tid_rdma_schedule_tid_wakeup(fqp);
+	}
+}
+
+void hfi1_kern_init_ctxt_generations(struct hfi1_ctxtdata *rcd)
+{
+	int i;
+
+	for (i = 0; i < RXE_NUM_TID_FLOWS; i++) {
+		rcd->flows[i].generation = mask_generation(get_random_u32());
+		kern_set_hw_flow(rcd, KERN_GENERATION_RESERVED, i);
+	}
+}
+
+/* TID allocation functions */
+static u8 trdma_pset_order(struct tid_rdma_pageset *s)
+{
+	u8 count = s->count;
+
+	return ilog2(count) + 1;
+}
+
+/**
+ * tid_rdma_find_phys_blocks_4k - get groups base on mr info
+ * @flow: overall info for a TID RDMA segment
+ * @pages: pointer to an array of page structs
+ * @npages: number of pages
+ * @list: page set array to return
+ *
+ * This routine returns the number of groups associated with
+ * the current sge information.  This implementation is based
+ * on the expected receive find_phys_blocks() adjusted to
+ * use the MR information vs. the pfn.
+ *
+ * Return:
+ * the number of RcvArray entries
+ */
+static u32 tid_rdma_find_phys_blocks_4k(struct tid_rdma_flow *flow,
+					struct page **pages,
+					u32 npages,
+					struct tid_rdma_pageset *list)
+{
+	u32 pagecount, pageidx, setcount = 0, i;
+	void *vaddr, *this_vaddr;
+
+	if (!npages)
+		return 0;
+
+	/*
+	 * Look for sets of physically contiguous pages in the user buffer.
+	 * This will allow us to optimize Expected RcvArray entry usage by
+	 * using the bigger supported sizes.
+	 */
+	vaddr = page_address(pages[0]);
+	trace_hfi1_tid_flow_page(flow->req->qp, flow, 0, 0, 0, vaddr);
+	for (pageidx = 0, pagecount = 1, i = 1; i <= npages; i++) {
+		this_vaddr = i < npages ? page_address(pages[i]) : NULL;
+		trace_hfi1_tid_flow_page(flow->req->qp, flow, i, 0, 0,
+					 this_vaddr);
+		/*
+		 * If the vaddr's are not sequential, pages are not physically
+		 * contiguous.
+		 */
+		if (this_vaddr != (vaddr + PAGE_SIZE)) {
+			/*
+			 * At this point we have to loop over the set of
+			 * physically contiguous pages and break them down it
+			 * sizes supported by the HW.
+			 * There are two main constraints:
+			 *     1. The max buffer size is MAX_EXPECTED_BUFFER.
+			 *        If the total set size is bigger than that
+			 *        program only a MAX_EXPECTED_BUFFER chunk.
+			 *     2. The buffer size has to be a power of two. If
+			 *        it is not, round down to the closes power of
+			 *        2 and program that size.
+			 */
+			while (pagecount) {
+				int maxpages = pagecount;
+				u32 bufsize = pagecount * PAGE_SIZE;
+
+				if (bufsize > MAX_EXPECTED_BUFFER)
+					maxpages =
+						MAX_EXPECTED_BUFFER >>
+						PAGE_SHIFT;
+				else if (!is_power_of_2(bufsize))
+					maxpages =
+						rounddown_pow_of_two(bufsize) >>
+						PAGE_SHIFT;
+
+				list[setcount].idx = pageidx;
+				list[setcount].count = maxpages;
+				trace_hfi1_tid_pageset(flow->req->qp, setcount,
+						       list[setcount].idx,
+						       list[setcount].count);
+				pagecount -= maxpages;
+				pageidx += maxpages;
+				setcount++;
+			}
+			pageidx = i;
+			pagecount = 1;
+			vaddr = this_vaddr;
+		} else {
+			vaddr += PAGE_SIZE;
+			pagecount++;
+		}
+	}
+	/* insure we always return an even number of sets */
+	if (setcount & 1)
+		list[setcount++].count = 0;
+	return setcount;
+}
+
+/**
+ * tid_flush_pages - dump out pages into pagesets
+ * @list: list of pagesets
+ * @idx: pointer to current page index
+ * @pages: number of pages to dump
+ * @sets: current number of pagesset
+ *
+ * This routine flushes out accumuated pages.
+ *
+ * To insure an even number of sets the
+ * code may add a filler.
+ *
+ * This can happen with when pages is not
+ * a power of 2 or pages is a power of 2
+ * less than the maximum pages.
+ *
+ * Return:
+ * The new number of sets
+ */
+
+static u32 tid_flush_pages(struct tid_rdma_pageset *list,
+			   u32 *idx, u32 pages, u32 sets)
+{
+	while (pages) {
+		u32 maxpages = pages;
+
+		if (maxpages > MAX_EXPECTED_PAGES)
+			maxpages = MAX_EXPECTED_PAGES;
+		else if (!is_power_of_2(maxpages))
+			maxpages = rounddown_pow_of_two(maxpages);
+		list[sets].idx = *idx;
+		list[sets++].count = maxpages;
+		*idx += maxpages;
+		pages -= maxpages;
+	}
+	/* might need a filler */
+	if (sets & 1)
+		list[sets++].count = 0;
+	return sets;
+}
+
+/**
+ * tid_rdma_find_phys_blocks_8k - get groups base on mr info
+ * @flow: overall info for a TID RDMA segment
+ * @pages: pointer to an array of page structs
+ * @npages: number of pages
+ * @list: page set array to return
+ *
+ * This routine parses an array of pages to compute pagesets
+ * in an 8k compatible way.
+ *
+ * pages are tested two at a time, i, i + 1 for contiguous
+ * pages and i - 1 and i contiguous pages.
+ *
+ * If any condition is false, any accumlated pages are flushed and
+ * v0,v1 are emitted as separate PAGE_SIZE pagesets
+ *
+ * Otherwise, the current 8k is totaled for a future flush.
+ *
+ * Return:
+ * The number of pagesets
+ * list set with the returned number of pagesets
+ *
+ */
+static u32 tid_rdma_find_phys_blocks_8k(struct tid_rdma_flow *flow,
+					struct page **pages,
+					u32 npages,
+					struct tid_rdma_pageset *list)
+{
+	u32 idx, sets = 0, i;
+	u32 pagecnt = 0;
+	void *v0, *v1, *vm1;
+
+	if (!npages)
+		return 0;
+	for (idx = 0, i = 0, vm1 = NULL; i < npages; i += 2) {
+		/* get a new v0 */
+		v0 = page_address(pages[i]);
+		trace_hfi1_tid_flow_page(flow->req->qp, flow, i, 1, 0, v0);
+		v1 = i + 1 < npages ?
+				page_address(pages[i + 1]) : NULL;
+		trace_hfi1_tid_flow_page(flow->req->qp, flow, i, 1, 1, v1);
+		/* compare i, i + 1 vaddr */
+		if (v1 != (v0 + PAGE_SIZE)) {
+			/* flush out pages */
+			sets = tid_flush_pages(list, &idx, pagecnt, sets);
+			/* output v0,v1 as two pagesets */
+			list[sets].idx = idx++;
+			list[sets++].count = 1;
+			if (v1) {
+				list[sets].count = 1;
+				list[sets++].idx = idx++;
+			} else {
+				list[sets++].count = 0;
+			}
+			vm1 = NULL;
+			pagecnt = 0;
+			continue;
+		}
+		/* i,i+1 consecutive, look at i-1,i */
+		if (vm1 && v0 != (vm1 + PAGE_SIZE)) {
+			/* flush out pages */
+			sets = tid_flush_pages(list, &idx, pagecnt, sets);
+			pagecnt = 0;
+		}
+		/* pages will always be a multiple of 8k */
+		pagecnt += 2;
+		/* save i-1 */
+		vm1 = v1;
+		/* move to next pair */
+	}
+	/* dump residual pages at end */
+	sets = tid_flush_pages(list, &idx, npages - idx, sets);
+	/* by design cannot be odd sets */
+	WARN_ON(sets & 1);
+	return sets;
+}
+
+/*
+ * Find pages for one segment of a sge array represented by @ss. The function
+ * does not check the sge, the sge must have been checked for alignment with a
+ * prior call to hfi1_kern_trdma_ok. Other sge checking is done as part of
+ * rvt_lkey_ok and rvt_rkey_ok. Also, the function only modifies the local sge
+ * copy maintained in @ss->sge, the original sge is not modified.
+ *
+ * Unlike IB RDMA WRITE, we can't decrement ss->num_sge here because we are not
+ * releasing the MR reference count at the same time. Otherwise, we'll "leak"
+ * references to the MR. This difference requires that we keep track of progress
+ * into the sg_list. This is done by the cur_seg cursor in the tid_rdma_request
+ * structure.
+ */
+static u32 kern_find_pages(struct tid_rdma_flow *flow,
+			   struct page **pages,
+			   struct rvt_sge_state *ss, bool *last)
+{
+	struct tid_rdma_request *req = flow->req;
+	struct rvt_sge *sge = &ss->sge;
+	u32 length = flow->req->seg_len;
+	u32 len = PAGE_SIZE;
+	u32 i = 0;
+
+	while (length && req->isge < ss->num_sge) {
+		pages[i++] = virt_to_page(sge->vaddr);
+
+		sge->vaddr += len;
+		sge->length -= len;
+		sge->sge_length -= len;
+		if (!sge->sge_length) {
+			if (++req->isge < ss->num_sge)
+				*sge = ss->sg_list[req->isge - 1];
+		} else if (sge->length == 0 && sge->mr->lkey) {
+			if (++sge->n >= RVT_SEGSZ) {
+				++sge->m;
+				sge->n = 0;
+			}
+			sge->vaddr = sge->mr->map[sge->m]->segs[sge->n].vaddr;
+			sge->length = sge->mr->map[sge->m]->segs[sge->n].length;
+		}
+		length -= len;
+	}
+
+	flow->length = flow->req->seg_len - length;
+	*last = req->isge != ss->num_sge;
+	return i;
+}
+
+static void dma_unmap_flow(struct tid_rdma_flow *flow)
+{
+	struct hfi1_devdata *dd;
+	int i;
+	struct tid_rdma_pageset *pset;
+
+	dd = flow->req->rcd->dd;
+	for (i = 0, pset = &flow->pagesets[0]; i < flow->npagesets;
+			i++, pset++) {
+		if (pset->count && pset->addr) {
+			dma_unmap_page(&dd->pcidev->dev,
+				       pset->addr,
+				       PAGE_SIZE * pset->count,
+				       DMA_FROM_DEVICE);
+			pset->mapped = 0;
+		}
+	}
+}
+
+static int dma_map_flow(struct tid_rdma_flow *flow, struct page **pages)
+{
+	int i;
+	struct hfi1_devdata *dd = flow->req->rcd->dd;
+	struct tid_rdma_pageset *pset;
+
+	for (i = 0, pset = &flow->pagesets[0]; i < flow->npagesets;
+			i++, pset++) {
+		if (pset->count) {
+			pset->addr = dma_map_page(&dd->pcidev->dev,
+						  pages[pset->idx],
+						  0,
+						  PAGE_SIZE * pset->count,
+						  DMA_FROM_DEVICE);
+
+			if (dma_mapping_error(&dd->pcidev->dev, pset->addr)) {
+				dma_unmap_flow(flow);
+				return -ENOMEM;
+			}
+			pset->mapped = 1;
+		}
+	}
+	return 0;
+}
+
+static inline bool dma_mapped(struct tid_rdma_flow *flow)
+{
+	return !!flow->pagesets[0].mapped;
+}
+
+/*
+ * Get pages pointers and identify contiguous physical memory chunks for a
+ * segment. All segments are of length flow->req->seg_len.
+ */
+static int kern_get_phys_blocks(struct tid_rdma_flow *flow,
+				struct page **pages,
+				struct rvt_sge_state *ss, bool *last)
+{
+	u8 npages;
+
+	/* Reuse previously computed pagesets, if any */
+	if (flow->npagesets) {
+		trace_hfi1_tid_flow_alloc(flow->req->qp, flow->req->setup_head,
+					  flow);
+		if (!dma_mapped(flow))
+			return dma_map_flow(flow, pages);
+		return 0;
+	}
+
+	npages = kern_find_pages(flow, pages, ss, last);
+
+	if (flow->req->qp->pmtu == enum_to_mtu(OPA_MTU_4096))
+		flow->npagesets =
+			tid_rdma_find_phys_blocks_4k(flow, pages, npages,
+						     flow->pagesets);
+	else
+		flow->npagesets =
+			tid_rdma_find_phys_blocks_8k(flow, pages, npages,
+						     flow->pagesets);
+
+	return dma_map_flow(flow, pages);
+}
+
+static inline void kern_add_tid_node(struct tid_rdma_flow *flow,
+				     struct hfi1_ctxtdata *rcd, char *s,
+				     struct tid_group *grp, u8 cnt)
+{
+	struct kern_tid_node *node = &flow->tnode[flow->tnode_cnt++];
+
+	WARN_ON_ONCE(flow->tnode_cnt >=
+		     (TID_RDMA_MAX_SEGMENT_SIZE >> PAGE_SHIFT));
+	if (WARN_ON_ONCE(cnt & 1))
+		dd_dev_err(rcd->dd,
+			   "unexpected odd allocation cnt %u map 0x%x used %u",
+			   cnt, grp->map, grp->used);
+
+	node->grp = grp;
+	node->map = grp->map;
+	node->cnt = cnt;
+	trace_hfi1_tid_node_add(flow->req->qp, s, flow->tnode_cnt - 1,
+				grp->base, grp->map, grp->used, cnt);
+}
+
+/*
+ * Try to allocate pageset_count TID's from TID groups for a context
+ *
+ * This function allocates TID's without moving groups between lists or
+ * modifying grp->map. This is done as follows, being cogizant of the lists
+ * between which the TID groups will move:
+ * 1. First allocate complete groups of 8 TID's since this is more efficient,
+ *    these groups will move from group->full without affecting used
+ * 2. If more TID's are needed allocate from used (will move from used->full or
+ *    stay in used)
+ * 3. If we still don't have the required number of TID's go back and look again
+ *    at a complete group (will move from group->used)
+ */
+static int kern_alloc_tids(struct tid_rdma_flow *flow)
+{
+	struct hfi1_ctxtdata *rcd = flow->req->rcd;
+	struct hfi1_devdata *dd = rcd->dd;
+	u32 ngroups, pageidx = 0;
+	struct tid_group *group = NULL, *used;
+	u8 use;
+
+	flow->tnode_cnt = 0;
+	ngroups = flow->npagesets / dd->rcv_entries.group_size;
+	if (!ngroups)
+		goto used_list;
+
+	/* First look at complete groups */
+	list_for_each_entry(group,  &rcd->tid_group_list.list, list) {
+		kern_add_tid_node(flow, rcd, "complete groups", group,
+				  group->size);
+
+		pageidx += group->size;
+		if (!--ngroups)
+			break;
+	}
+
+	if (pageidx >= flow->npagesets)
+		goto ok;
+
+used_list:
+	/* Now look at partially used groups */
+	list_for_each_entry(used, &rcd->tid_used_list.list, list) {
+		use = min_t(u32, flow->npagesets - pageidx,
+			    used->size - used->used);
+		kern_add_tid_node(flow, rcd, "used groups", used, use);
+
+		pageidx += use;
+		if (pageidx >= flow->npagesets)
+			goto ok;
+	}
+
+	/*
+	 * Look again at a complete group, continuing from where we left.
+	 * However, if we are at the head, we have reached the end of the
+	 * complete groups list from the first loop above
+	 */
+	if (group && &group->list == &rcd->tid_group_list.list)
+		goto bail_eagain;
+	group = list_prepare_entry(group, &rcd->tid_group_list.list,
+				   list);
+	if (list_is_last(&group->list, &rcd->tid_group_list.list))
+		goto bail_eagain;
+	group = list_next_entry(group, list);
+	use = min_t(u32, flow->npagesets - pageidx, group->size);
+	kern_add_tid_node(flow, rcd, "complete continue", group, use);
+	pageidx += use;
+	if (pageidx >= flow->npagesets)
+		goto ok;
+bail_eagain:
+	trace_hfi1_msg_alloc_tids(flow->req->qp, " insufficient tids: needed ",
+				  (u64)flow->npagesets);
+	return -EAGAIN;
+ok:
+	return 0;
+}
+
+static void kern_program_rcv_group(struct tid_rdma_flow *flow, int grp_num,
+				   u32 *pset_idx)
+{
+	struct hfi1_ctxtdata *rcd = flow->req->rcd;
+	struct hfi1_devdata *dd = rcd->dd;
+	struct kern_tid_node *node = &flow->tnode[grp_num];
+	struct tid_group *grp = node->grp;
+	struct tid_rdma_pageset *pset;
+	u32 pmtu_pg = flow->req->qp->pmtu >> PAGE_SHIFT;
+	u32 rcventry, npages = 0, pair = 0, tidctrl;
+	u8 i, cnt = 0;
+
+	for (i = 0; i < grp->size; i++) {
+		rcventry = grp->base + i;
+
+		if (node->map & BIT(i) || cnt >= node->cnt) {
+			rcv_array_wc_fill(dd, rcventry);
+			continue;
+		}
+		pset = &flow->pagesets[(*pset_idx)++];
+		if (pset->count) {
+			hfi1_put_tid(dd, rcventry, PT_EXPECTED,
+				     pset->addr, trdma_pset_order(pset));
+		} else {
+			hfi1_put_tid(dd, rcventry, PT_INVALID, 0, 0);
+		}
+		npages += pset->count;
+
+		rcventry -= rcd->expected_base;
+		tidctrl = pair ? 0x3 : rcventry & 0x1 ? 0x2 : 0x1;
+		/*
+		 * A single TID entry will be used to use a rcvarr pair (with
+		 * tidctrl 0x3), if ALL these are true (a) the bit pos is even
+		 * (b) the group map shows current and the next bits as free
+		 * indicating two consecutive rcvarry entries are available (c)
+		 * we actually need 2 more entries
+		 */
+		pair = !(i & 0x1) && !((node->map >> i) & 0x3) &&
+			node->cnt >= cnt + 2;
+		if (!pair) {
+			if (!pset->count)
+				tidctrl = 0x1;
+			flow->tid_entry[flow->tidcnt++] =
+				EXP_TID_SET(IDX, rcventry >> 1) |
+				EXP_TID_SET(CTRL, tidctrl) |
+				EXP_TID_SET(LEN, npages);
+			trace_hfi1_tid_entry_alloc(/* entry */
+			   flow->req->qp, flow->tidcnt - 1,
+			   flow->tid_entry[flow->tidcnt - 1]);
+
+			/* Efficient DIV_ROUND_UP(npages, pmtu_pg) */
+			flow->npkts += (npages + pmtu_pg - 1) >> ilog2(pmtu_pg);
+			npages = 0;
+		}
+
+		if (grp->used == grp->size - 1)
+			tid_group_move(grp, &rcd->tid_used_list,
+				       &rcd->tid_full_list);
+		else if (!grp->used)
+			tid_group_move(grp, &rcd->tid_group_list,
+				       &rcd->tid_used_list);
+
+		grp->used++;
+		grp->map |= BIT(i);
+		cnt++;
+	}
+}
+
+static void kern_unprogram_rcv_group(struct tid_rdma_flow *flow, int grp_num)
+{
+	struct hfi1_ctxtdata *rcd = flow->req->rcd;
+	struct hfi1_devdata *dd = rcd->dd;
+	struct kern_tid_node *node = &flow->tnode[grp_num];
+	struct tid_group *grp = node->grp;
+	u32 rcventry;
+	u8 i, cnt = 0;
+
+	for (i = 0; i < grp->size; i++) {
+		rcventry = grp->base + i;
+
+		if (node->map & BIT(i) || cnt >= node->cnt) {
+			rcv_array_wc_fill(dd, rcventry);
+			continue;
+		}
+
+		hfi1_put_tid(dd, rcventry, PT_INVALID, 0, 0);
+
+		grp->used--;
+		grp->map &= ~BIT(i);
+		cnt++;
+
+		if (grp->used == grp->size - 1)
+			tid_group_move(grp, &rcd->tid_full_list,
+				       &rcd->tid_used_list);
+		else if (!grp->used)
+			tid_group_move(grp, &rcd->tid_used_list,
+				       &rcd->tid_group_list);
+	}
+	if (WARN_ON_ONCE(cnt & 1)) {
+		struct hfi1_ctxtdata *rcd = flow->req->rcd;
+		struct hfi1_devdata *dd = rcd->dd;
+
+		dd_dev_err(dd, "unexpected odd free cnt %u map 0x%x used %u",
+			   cnt, grp->map, grp->used);
+	}
+}
+
+static void kern_program_rcvarray(struct tid_rdma_flow *flow)
+{
+	u32 pset_idx = 0;
+	int i;
+
+	flow->npkts = 0;
+	flow->tidcnt = 0;
+	for (i = 0; i < flow->tnode_cnt; i++)
+		kern_program_rcv_group(flow, i, &pset_idx);
+	trace_hfi1_tid_flow_alloc(flow->req->qp, flow->req->setup_head, flow);
+}
+
+/**
+ * hfi1_kern_exp_rcv_setup() - setup TID's and flow for one segment of a
+ * TID RDMA request
+ *
+ * @req: TID RDMA request for which the segment/flow is being set up
+ * @ss: sge state, maintains state across successive segments of a sge
+ * @last: set to true after the last sge segment has been processed
+ *
+ * This function
+ * (1) finds a free flow entry in the flow circular buffer
+ * (2) finds pages and continuous physical chunks constituing one segment
+ *     of an sge
+ * (3) allocates TID group entries for those chunks
+ * (4) programs rcvarray entries in the hardware corresponding to those
+ *     TID's
+ * (5) computes a tidarray with formatted TID entries which can be sent
+ *     to the sender
+ * (6) Reserves and programs HW flows.
+ * (7) It also manages queing the QP when TID/flow resources are not
+ *     available.
+ *
+ * @req points to struct tid_rdma_request of which the segments are a part. The
+ * function uses qp, rcd and seg_len members of @req. In the absence of errors,
+ * req->flow_idx is the index of the flow which has been prepared in this
+ * invocation of function call. With flow = &req->flows[req->flow_idx],
+ * flow->tid_entry contains the TID array which the sender can use for TID RDMA
+ * sends and flow->npkts contains number of packets required to send the
+ * segment.
+ *
+ * hfi1_check_sge_align should be called prior to calling this function and if
+ * it signals error TID RDMA cannot be used for this sge and this function
+ * should not be called.
+ *
+ * For the queuing, caller must hold the flow->req->qp s_lock from the send
+ * engine and the function will procure the exp_lock.
+ *
+ * Return:
+ * The function returns -EAGAIN if sufficient number of TID/flow resources to
+ * map the segment could not be allocated. In this case the function should be
+ * called again with previous arguments to retry the TID allocation. There are
+ * no other error returns. The function returns 0 on success.
+ */
+int hfi1_kern_exp_rcv_setup(struct tid_rdma_request *req,
+			    struct rvt_sge_state *ss, bool *last)
+	__must_hold(&req->qp->s_lock)
+{
+	struct tid_rdma_flow *flow = &req->flows[req->setup_head];
+	struct hfi1_ctxtdata *rcd = req->rcd;
+	struct hfi1_qp_priv *qpriv = req->qp->priv;
+	unsigned long flags;
+	struct rvt_qp *fqp;
+	u16 clear_tail = req->clear_tail;
+
+	lockdep_assert_held(&req->qp->s_lock);
+	/*
+	 * We return error if either (a) we don't have space in the flow
+	 * circular buffer, or (b) we already have max entries in the buffer.
+	 * Max entries depend on the type of request we are processing and the
+	 * negotiated TID RDMA parameters.
+	 */
+	if (!CIRC_SPACE(req->setup_head, clear_tail, MAX_FLOWS) ||
+	    CIRC_CNT(req->setup_head, clear_tail, MAX_FLOWS) >=
+	    req->n_flows)
+		return -EINVAL;
+
+	/*
+	 * Get pages, identify contiguous physical memory chunks for the segment
+	 * If we can not determine a DMA address mapping we will treat it just
+	 * like if we ran out of space above.
+	 */
+	if (kern_get_phys_blocks(flow, qpriv->pages, ss, last)) {
+		hfi1_wait_kmem(flow->req->qp);
+		return -ENOMEM;
+	}
+
+	spin_lock_irqsave(&rcd->exp_lock, flags);
+	if (kernel_tid_waiters(rcd, &rcd->rarr_queue, flow->req->qp))
+		goto queue;
+
+	/*
+	 * At this point we know the number of pagesets and hence the number of
+	 * TID's to map the segment. Allocate the TID's from the TID groups. If
+	 * we cannot allocate the required number we exit and try again later
+	 */
+	if (kern_alloc_tids(flow))
+		goto queue;
+	/*
+	 * Finally program the TID entries with the pagesets, compute the
+	 * tidarray and enable the HW flow
+	 */
+	kern_program_rcvarray(flow);
+
+	/*
+	 * Setup the flow state with relevant information.
+	 * This information is used for tracking the sequence of data packets
+	 * for the segment.
+	 * The flow is setup here as this is the most accurate time and place
+	 * to do so. Doing at a later time runs the risk of the flow data in
+	 * qpriv getting out of sync.
+	 */
+	memset(&flow->flow_state, 0x0, sizeof(flow->flow_state));
+	flow->idx = qpriv->flow_state.index;
+	flow->flow_state.generation = qpriv->flow_state.generation;
+	flow->flow_state.spsn = qpriv->flow_state.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);
+	qpriv->flow_state.psn += flow->npkts;
+
+	dequeue_tid_waiter(rcd, &rcd->rarr_queue, flow->req->qp);
+	/* get head before dropping lock */
+	fqp = first_qp(rcd, &rcd->rarr_queue);
+	spin_unlock_irqrestore(&rcd->exp_lock, flags);
+	tid_rdma_schedule_tid_wakeup(fqp);
+
+	req->setup_head = (req->setup_head + 1) & (MAX_FLOWS - 1);
+	return 0;
+queue:
+	queue_qp_for_tid_wait(rcd, &rcd->rarr_queue, flow->req->qp);
+	spin_unlock_irqrestore(&rcd->exp_lock, flags);
+	return -EAGAIN;
+}
+
+static void hfi1_tid_rdma_reset_flow(struct tid_rdma_flow *flow)
+{
+	flow->npagesets = 0;
+}
+
+/*
+ * This function is called after one segment has been successfully sent to
+ * release the flow and TID HW/SW resources for that segment. The segments for a
+ * TID RDMA request are setup and cleared in FIFO order which is managed using a
+ * circular buffer.
+ */
+int hfi1_kern_exp_rcv_clear(struct tid_rdma_request *req)
+	__must_hold(&req->qp->s_lock)
+{
+	struct tid_rdma_flow *flow = &req->flows[req->clear_tail];
+	struct hfi1_ctxtdata *rcd = req->rcd;
+	unsigned long flags;
+	int i;
+	struct rvt_qp *fqp;
+
+	lockdep_assert_held(&req->qp->s_lock);
+	/* Exit if we have nothing in the flow circular buffer */
+	if (!CIRC_CNT(req->setup_head, req->clear_tail, MAX_FLOWS))
+		return -EINVAL;
+
+	spin_lock_irqsave(&rcd->exp_lock, flags);
+
+	for (i = 0; i < flow->tnode_cnt; i++)
+		kern_unprogram_rcv_group(flow, i);
+	/* To prevent double unprogramming */
+	flow->tnode_cnt = 0;
+	/* get head before dropping lock */
+	fqp = first_qp(rcd, &rcd->rarr_queue);
+	spin_unlock_irqrestore(&rcd->exp_lock, flags);
+
+	dma_unmap_flow(flow);
+
+	hfi1_tid_rdma_reset_flow(flow);
+	req->clear_tail = (req->clear_tail + 1) & (MAX_FLOWS - 1);
+
+	if (fqp == req->qp) {
+		__trigger_tid_waiter(fqp);
+		rvt_put_qp(fqp);
+	} else {
+		tid_rdma_schedule_tid_wakeup(fqp);
+	}
+
+	return 0;
+}
+
+/*
+ * This function is called to release all the tid entries for
+ * a request.
+ */
+void hfi1_kern_exp_rcv_clear_all(struct tid_rdma_request *req)
+	__must_hold(&req->qp->s_lock)
+{
+	/* Use memory barrier for proper ordering */
+	while (CIRC_CNT(req->setup_head, req->clear_tail, MAX_FLOWS)) {
+		if (hfi1_kern_exp_rcv_clear(req))
+			break;
+	}
+}
+
+/**
+ * hfi1_kern_exp_rcv_free_flows - free priviously allocated flow information
+ * @req: the tid rdma request to be cleaned
+ */
+static void hfi1_kern_exp_rcv_free_flows(struct tid_rdma_request *req)
+{
+	kfree(req->flows);
+	req->flows = NULL;
+}
+
+/**
+ * __trdma_clean_swqe - clean up for large sized QPs
+ * @qp: the queue patch
+ * @wqe: the send wqe
+ */
+void __trdma_clean_swqe(struct rvt_qp *qp, struct rvt_swqe *wqe)
+{
+	struct hfi1_swqe_priv *p = wqe->priv;
+
+	hfi1_kern_exp_rcv_free_flows(&p->tid_req);
+}
+
+/*
+ * This can be called at QP create time or in the data path.
+ */
+static int hfi1_kern_exp_rcv_alloc_flows(struct tid_rdma_request *req,
+					 gfp_t gfp)
+{
+	struct tid_rdma_flow *flows;
+	int i;
+
+	if (likely(req->flows))
+		return 0;
+	flows = kmalloc_node(MAX_FLOWS * sizeof(*flows), gfp,
+			     req->rcd->numa_id);
+	if (!flows)
+		return -ENOMEM;
+	/* mini init */
+	for (i = 0; i < MAX_FLOWS; i++) {
+		flows[i].req = req;
+		flows[i].npagesets = 0;
+		flows[i].pagesets[0].mapped =  0;
+		flows[i].resync_npkts = 0;
+	}
+	req->flows = flows;
+	return 0;
+}
+
+static void hfi1_init_trdma_req(struct rvt_qp *qp,
+				struct tid_rdma_request *req)
+{
+	struct hfi1_qp_priv *qpriv = qp->priv;
+
+	/*
+	 * Initialize various TID RDMA request variables.
+	 * These variables are "static", which is why they
+	 * can be pre-initialized here before the WRs has
+	 * even been submitted.
+	 * However, non-NULL values for these variables do not
+	 * imply that this WQE has been enabled for TID RDMA.
+	 * Drivers should check the WQE's opcode to determine
+	 * if a request is a TID RDMA one or not.
+	 */
+	req->qp = qp;
+	req->rcd = qpriv->rcd;
+}
+
+u64 hfi1_access_sw_tid_wait(const struct cntr_entry *entry,
+			    void *context, int vl, int mode, u64 data)
+{
+	struct hfi1_devdata *dd = context;
+
+	return dd->verbs_dev.n_tidwait;
+}
+
+static struct tid_rdma_flow *find_flow_ib(struct tid_rdma_request *req,
+					  u32 psn, u16 *fidx)
+{
+	u16 head, tail;
+	struct tid_rdma_flow *flow;
+
+	head = req->setup_head;
+	tail = req->clear_tail;
+	for ( ; CIRC_CNT(head, tail, MAX_FLOWS);
+	     tail = CIRC_NEXT(tail, MAX_FLOWS)) {
+		flow = &req->flows[tail];
+		if (cmp_psn(psn, flow->flow_state.ib_spsn) >= 0 &&
+		    cmp_psn(psn, flow->flow_state.ib_lpsn) <= 0) {
+			if (fidx)
+				*fidx = tail;
+			return flow;
+		}
+	}
+	return NULL;
+}
+
+/* TID RDMA READ functions */
+u32 hfi1_build_tid_rdma_read_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->flow_idx];
+	struct rvt_qp *qp = req->qp;
+	struct hfi1_qp_priv *qpriv = qp->priv;
+	struct hfi1_swqe_priv *wpriv = wqe->priv;
+	struct tid_rdma_read_req *rreq = &ohdr->u.tid_rdma.r_req;
+	struct tid_rdma_params *remote;
+	u32 req_len = 0;
+	void *req_addr = NULL;
+
+	/* This is the IB psn used to send the request */
+	*bth2 = mask_psn(flow->flow_state.ib_spsn + flow->pkt);
+	trace_hfi1_tid_flow_build_read_pkt(qp, req->flow_idx, flow);
+
+	/* TID Entries for TID RDMA READ payload */
+	req_addr = &flow->tid_entry[flow->tid_idx];
+	req_len = sizeof(*flow->tid_entry) *
+			(flow->tidcnt - flow->tid_idx);
+
+	memset(&ohdr->u.tid_rdma.r_req, 0, sizeof(ohdr->u.tid_rdma.r_req));
+	wpriv->ss.sge.vaddr = req_addr;
+	wpriv->ss.sge.sge_length = req_len;
+	wpriv->ss.sge.length = wpriv->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.
+	 */
+	wpriv->ss.sge.mr = NULL;
+	wpriv->ss.sge.m = 0;
+	wpriv->ss.sge.n = 0;
+
+	wpriv->ss.sg_list = NULL;
+	wpriv->ss.total_len = wpriv->ss.sge.sge_length;
+	wpriv->ss.num_sge = 1;
+
+	/* Construct the TID RDMA READ REQ packet header */
+	rcu_read_lock();
+	remote = rcu_dereference(qpriv->tid_rdma.remote);
+
+	KDETH_RESET(rreq->kdeth0, KVER, 0x1);
+	KDETH_RESET(rreq->kdeth1, JKEY, remote->jkey);
+	rreq->reth.vaddr = cpu_to_be64(wqe->rdma_wr.remote_addr +
+			   req->cur_seg * req->seg_len + flow->sent);
+	rreq->reth.rkey = cpu_to_be32(wqe->rdma_wr.rkey);
+	rreq->reth.length = cpu_to_be32(*len);
+	rreq->tid_flow_psn =
+		cpu_to_be32((flow->flow_state.generation <<
+			     HFI1_KDETH_BTH_SEQ_SHIFT) |
+			    ((flow->flow_state.spsn + flow->pkt) &
+			     HFI1_KDETH_BTH_SEQ_MASK));
+	rreq->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);
+	rreq->verbs_qp = cpu_to_be32(qp->remote_qpn);
+	*bth1 &= ~RVT_QPN_MASK;
+	*bth1 |= remote->qp;
+	*bth2 |= IB_BTH_REQ_ACK;
+	rcu_read_unlock();
+
+	/* We are done with this segment */
+	flow->sent += *len;
+	req->cur_seg++;
+	qp->s_state = TID_OP(READ_REQ);
+	req->ack_pending++;
+	req->flow_idx = (req->flow_idx + 1) & (MAX_FLOWS - 1);
+	qpriv->pending_tid_r_segs++;
+	qp->s_num_rd_atomic++;
+
+	/* Set the TID RDMA READ request payload size */
+	*len = req_len;
+
+	return sizeof(ohdr->u.tid_rdma.r_req) / sizeof(u32);
+}
+
+/*
+ * @len: contains the data length to read upon entry and the read request
+ *       payload length upon exit.
+ */
+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)
+{
+	struct hfi1_qp_priv *qpriv = qp->priv;
+	struct tid_rdma_request *req = wqe_to_tid_req(wqe);
+	struct tid_rdma_flow *flow = NULL;
+	u32 hdwords = 0;
+	bool last;
+	bool retry = true;
+	u32 npkts = rvt_div_round_up_mtu(qp, *len);
+
+	trace_hfi1_tid_req_build_read_req(qp, 0, wqe->wr.opcode, wqe->psn,
+					  wqe->lpsn, req);
+	/*
+	 * Check sync conditions. Make sure that there are no pending
+	 * segments before freeing the flow.
+	 */
+sync_check:
+	if (req->state == TID_REQUEST_SYNC) {
+		if (qpriv->pending_tid_r_segs)
+			goto done;
+
+		hfi1_kern_clear_hw_flow(req->rcd, qp);
+		qpriv->s_flags &= ~HFI1_R_TID_SW_PSN;
+		req->state = TID_REQUEST_ACTIVE;
+	}
+
+	/*
+	 * If the request for this segment is resent, the tid resources should
+	 * have been allocated before. In this case, req->flow_idx should
+	 * fall behind req->setup_head.
+	 */
+	if (req->flow_idx == req->setup_head) {
+		retry = false;
+		if (req->state == TID_REQUEST_RESEND) {
+			/*
+			 * This is the first new segment for a request whose
+			 * earlier segments have been re-sent. We need to
+			 * set up the sge pointer correctly.
+			 */
+			restart_sge(&qp->s_sge, wqe, req->s_next_psn,
+				    qp->pmtu);
+			req->isge = 0;
+			req->state = TID_REQUEST_ACTIVE;
+		}
+
+		/*
+		 * Check sync. The last PSN of each generation is reserved for
+		 * RESYNC.
+		 */
+		if ((qpriv->flow_state.psn + npkts) > MAX_TID_FLOW_PSN - 1) {
+			req->state = TID_REQUEST_SYNC;
+			goto sync_check;
+		}
+
+		/* Allocate the flow if not yet */
+		if (hfi1_kern_setup_hw_flow(qpriv->rcd, qp))
+			goto done;
+
+		/*
+		 * The following call will advance req->setup_head after
+		 * allocating the tid entries.
+		 */
+		if (hfi1_kern_exp_rcv_setup(req, &qp->s_sge, &last)) {
+			req->state = TID_REQUEST_QUEUED;
+
+			/*
+			 * We don't have resources for this segment. The QP has
+			 * already been queued.
+			 */
+			goto done;
+		}
+	}
+
+	/* req->flow_idx should only be one slot behind req->setup_head */
+	flow = &req->flows[req->flow_idx];
+	flow->pkt = 0;
+	flow->tid_idx = 0;
+	flow->sent = 0;
+	if (!retry) {
+		/* Set the first and last IB PSN for the flow in use.*/
+		flow->flow_state.ib_spsn = req->s_next_psn;
+		flow->flow_state.ib_lpsn =
+			flow->flow_state.ib_spsn + flow->npkts - 1;
+	}
+
+	/* Calculate the next segment start psn.*/
+	req->s_next_psn += flow->npkts;
+
+	/* Build the packet header */
+	hdwords = hfi1_build_tid_rdma_read_packet(wqe, ohdr, bth1, bth2, len);
+done:
+	return hdwords;
+}
+
+/*
+ * Validate and accept the TID RDMA READ request parameters.
+ * Return 0 if the request is accepted successfully;
+ * Return 1 otherwise.
+ */
+static int tid_rdma_rcv_read_request(struct rvt_qp *qp,
+				     struct rvt_ack_entry *e,
+				     struct hfi1_packet *packet,
+				     struct ib_other_headers *ohdr,
+				     u32 bth0, u32 psn, u64 vaddr, u32 len)
+{
+	struct hfi1_qp_priv *qpriv = qp->priv;
+	struct tid_rdma_request *req;
+	struct tid_rdma_flow *flow;
+	u32 flow_psn, i, tidlen = 0, pktlen, tlen;
+
+	req = ack_to_tid_req(e);
+
+	/* Validate the payload first */
+	flow = &req->flows[req->setup_head];
+
+	/* payload length = packet length - (header length + ICRC length) */
+	pktlen = packet->tlen - (packet->hlen + 4);
+	if (pktlen > sizeof(flow->tid_entry))
+		return 1;
+	memcpy(flow->tid_entry, packet->ebuf, pktlen);
+	flow->tidcnt = pktlen / sizeof(*flow->tid_entry);
+
+	/*
+	 * Walk the TID_ENTRY list to make sure we have enough space for a
+	 * complete segment. Also calculate the number of required packets.
+	 */
+	flow->npkts = rvt_div_round_up_mtu(qp, len);
+	for (i = 0; i < flow->tidcnt; i++) {
+		trace_hfi1_tid_entry_rcv_read_req(qp, i,
+						  flow->tid_entry[i]);
+		tlen = EXP_TID_GET(flow->tid_entry[i], LEN);
+		if (!tlen)
+			return 1;
+
+		/*
+		 * For tid pair (tidctr == 3), the buffer size of the pair
+		 * should be the sum of the buffer size described by each
+		 * tid entry. However, only the first entry needs to be
+		 * specified in the request (see WFR HAS Section 8.5.7.1).
+		 */
+		tidlen += tlen;
+	}
+	if (tidlen * PAGE_SIZE < len)
+		return 1;
+
+	/* Empty the flow array */
+	req->clear_tail = req->setup_head;
+	flow->pkt = 0;
+	flow->tid_idx = 0;
+	flow->tid_offset = 0;
+	flow->sent = 0;
+	flow->tid_qpn = be32_to_cpu(ohdr->u.tid_rdma.r_req.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.r_req.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->length = len;
+
+	flow->flow_state.lpsn = flow->flow_state.spsn +
+		flow->npkts - 1;
+	flow->flow_state.ib_spsn = psn;
+	flow->flow_state.ib_lpsn = flow->flow_state.ib_spsn + flow->npkts - 1;
+
+	trace_hfi1_tid_flow_rcv_read_req(qp, req->setup_head, flow);
+	/* Set the initial flow index to the current flow. */
+	req->flow_idx = req->setup_head;
+
+	/* advance circular buffer head */
+	req->setup_head = (req->setup_head + 1) & (MAX_FLOWS - 1);
+
+	/*
+	 * Compute last PSN for request.
+	 */
+	e->opcode = (bth0 >> 24) & 0xff;
+	e->psn = psn;
+	e->lpsn = psn + flow->npkts - 1;
+	e->sent = 0;
+
+	req->n_flows = qpriv->tid_rdma.local.max_read;
+	req->state = TID_REQUEST_ACTIVE;
+	req->cur_seg = 0;
+	req->comp_seg = 0;
+	req->ack_seg = 0;
+	req->isge = 0;
+	req->seg_len = qpriv->tid_rdma.local.max_len;
+	req->total_len = len;
+	req->total_segs = 1;
+	req->r_flow_psn = e->psn;
+
+	trace_hfi1_tid_req_rcv_read_req(qp, 0, e->opcode, e->psn, e->lpsn,
+					req);
+	return 0;
+}
+
+static int tid_rdma_rcv_error(struct hfi1_packet *packet,
+			      struct ib_other_headers *ohdr,
+			      struct rvt_qp *qp, u32 psn, int diff)
+{
+	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;
+	u8 prev;
+	bool old_req;
+
+	trace_hfi1_rsp_tid_rcv_error(qp, psn);
+	trace_hfi1_tid_rdma_rcv_err(qp, 0, psn, diff);
+	if (diff > 0) {
+		/* sequence error */
+		if (!qp->r_nak_state) {
+			ibp->rvp.n_rc_seqnak++;
+			qp->r_nak_state = IB_NAK_PSN_ERROR;
+			qp->r_ack_psn = qp->r_psn;
+			rc_defered_ack(rcd, qp);
+		}
+		goto done;
+	}
+
+	ibp->rvp.n_rc_dupreq++;
+
+	spin_lock_irqsave(&qp->s_lock, flags);
+	e = find_prev_entry(qp, psn, &prev, NULL, &old_req);
+	if (!e || (e->opcode != TID_OP(READ_REQ) &&
+		   e->opcode != TID_OP(WRITE_REQ)))
+		goto unlock;
+
+	req = ack_to_tid_req(e);
+	req->r_flow_psn = psn;
+	trace_hfi1_tid_req_rcv_err(qp, 0, e->opcode, e->psn, e->lpsn, req);
+	if (e->opcode == TID_OP(READ_REQ)) {
+		struct ib_reth *reth;
+		u32 len;
+		u32 rkey;
+		u64 vaddr;
+		int ok;
+		u32 bth0;
+
+		reth = &ohdr->u.tid_rdma.r_req.reth;
+		/*
+		 * The requester always restarts from the start of the original
+		 * request.
+		 */
+		len = be32_to_cpu(reth->length);
+		if (psn != e->psn || len != req->total_len)
+			goto unlock;
+
+		release_rdma_sge_mr(e);
+
+		rkey = be32_to_cpu(reth->rkey);
+		vaddr = get_ib_reth_vaddr(reth);
+
+		qp->r_len = len;
+		ok = rvt_rkey_ok(qp, &e->rdma_sge, len, vaddr, rkey,
+				 IB_ACCESS_REMOTE_READ);
+		if (unlikely(!ok))
+			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;
+	} else {
+		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, MAX_FLOWS)) {
+			fstate = &req->flows[req->clear_tail].flow_state;
+			qpriv->pending_tid_w_segs -=
+				CIRC_CNT(req->flow_idx, req->clear_tail,
+					 MAX_FLOWS);
+			req->flow_idx =
+				CIRC_ADD(req->clear_tail,
+					 delta_psn(psn, fstate->resp_ib_psn),
+					 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,
+				     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);
+			trace_hfi1_tid_req_rcv_err(qp, 0, e->opcode, e->psn,
+						   e->lpsn, req);
+			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,
+					 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;
+	}
+	/* Re-process old requests.*/
+	if (qp->s_acked_ack_queue == qp->s_tail_ack_queue)
+		qp->s_acked_ack_queue = prev;
+	qp->s_tail_ack_queue = prev;
+	/*
+	 * Since the qp->s_tail_ack_queue is modified, the
+	 * qp->s_ack_state must be changed to re-initialize
+	 * qp->s_ack_rdma_sge; Otherwise, we will end up in
+	 * 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;
+	hfi1_schedule_send(qp);
+unlock:
+	spin_unlock_irqrestore(&qp->s_lock, flags);
+done:
+	return 1;
+}
+
+void hfi1_rc_rcv_tid_rdma_read_req(struct hfi1_packet *packet)
+{
+	/* HANDLER FOR TID RDMA READ REQUEST packet (Responder side)*/
+
+	/*
+	 * 1. Verify TID RDMA READ REQ as per IB_OPCODE_RC_RDMA_READ
+	 *    (see hfi1_rc_rcv())
+	 * 2. Put TID RDMA READ REQ into the response queueu (s_ack_queue)
+	 *     - Setup struct tid_rdma_req with request info
+	 *     - Initialize struct tid_rdma_flow info;
+	 *     - Copy TID entries;
+	 * 3. Set the qp->s_ack_state.
+	 * 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;
+	u32 bth0, psn, len, rkey;
+	bool fecn;
+	u8 next;
+	u64 vaddr;
+	int diff;
+	u8 nack_state = IB_NAK_INVALID_REQUEST;
+
+	bth0 = be32_to_cpu(ohdr->bth[0]);
+	if (hfi1_ruc_check_hdr(ibp, packet))
+		return;
+
+	fecn = process_ecn(qp, packet);
+	psn = mask_psn(be32_to_cpu(ohdr->bth[2]));
+	trace_hfi1_rsp_rcv_tid_read_req(qp, psn);
+
+	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_READ)))
+		goto nack_inv;
+
+	reth = &ohdr->u.tid_rdma.r_req.reth;
+	vaddr = be64_to_cpu(reth->vaddr);
+	len = be32_to_cpu(reth->length);
+	/* The length needs to be in multiples of PAGE_SIZE */
+	if (!len || len & ~PAGE_MASK || len > qpriv->tid_rdma.local.max_len)
+		goto nack_inv;
+
+	diff = delta_psn(psn, qp->r_psn);
+	if (unlikely(diff)) {
+		tid_rdma_rcv_err(packet, ohdr, qp, psn, diff, fecn);
+		return;
+	}
+
+	/* 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_tail_ack_queue)) {
+		if (!qp->s_ack_queue[next].sent) {
+			nack_state = IB_NAK_REMOTE_OPERATIONAL_ERROR;
+			goto nack_inv_unlock;
+		}
+		update_ack_queue(qp, next);
+	}
+	e = &qp->s_ack_queue[qp->r_head_ack_queue];
+	release_rdma_sge_mr(e);
+
+	rkey = be32_to_cpu(reth->rkey);
+	qp->r_len = len;
+
+	if (unlikely(!rvt_rkey_ok(qp, &e->rdma_sge, qp->r_len, vaddr,
+				  rkey, IB_ACCESS_REMOTE_READ)))
+		goto nack_acc;
+
+	/* Accept the request parameters */
+	if (tid_rdma_rcv_read_request(qp, e, packet, ohdr, bth0, psn, vaddr,
+				      len))
+		goto nack_inv_unlock;
+
+	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 += e->lpsn - e->psn + 1;
+
+	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;
+	if (fecn)
+		qp->s_flags |= RVT_S_ECN;
+	hfi1_schedule_send(qp);
+
+	spin_unlock_irqrestore(&qp->s_lock, flags);
+	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 = nack_state;
+	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;
+}
+
+u32 hfi1_build_tid_rdma_read_resp(struct rvt_qp *qp, struct rvt_ack_entry *e,
+				  struct ib_other_headers *ohdr, u32 *bth0,
+				  u32 *bth1, u32 *bth2, u32 *len, bool *last)
+{
+	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 = &req->flows[req->clear_tail];
+	u32 tidentry = flow->tid_entry[flow->tid_idx];
+	u32 tidlen = EXP_TID_GET(tidentry, LEN) << PAGE_SHIFT;
+	struct tid_rdma_read_resp *resp = &ohdr->u.tid_rdma.r_rsp;
+	u32 next_offset, om = KDETH_OM_LARGE;
+	bool last_pkt;
+	u32 hdwords = 0;
+	struct tid_rdma_params *remote;
+
+	*len = min_t(u32, qp->pmtu, tidlen - flow->tid_offset);
+	flow->sent += *len;
+	next_offset = flow->tid_offset + *len;
+	last_pkt = (flow->sent >= flow->length);
+
+	trace_hfi1_tid_entry_build_read_resp(qp, flow->tid_idx, tidentry);
+	trace_hfi1_tid_flow_build_read_resp(qp, req->clear_tail, flow);
+
+	rcu_read_lock();
+	remote = rcu_dereference(qpriv->tid_rdma.remote);
+	if (!remote) {
+		rcu_read_unlock();
+		goto done;
+	}
+	KDETH_RESET(resp->kdeth0, KVER, 0x1);
+	KDETH_SET(resp->kdeth0, SH, !last_pkt);
+	KDETH_SET(resp->kdeth0, INTR, !!(!last_pkt && remote->urg));
+	KDETH_SET(resp->kdeth0, TIDCTRL, EXP_TID_GET(tidentry, CTRL));
+	KDETH_SET(resp->kdeth0, TID, EXP_TID_GET(tidentry, IDX));
+	KDETH_SET(resp->kdeth0, OM, om == KDETH_OM_LARGE);
+	KDETH_SET(resp->kdeth0, OFFSET, flow->tid_offset / om);
+	KDETH_RESET(resp->kdeth1, JKEY, remote->jkey);
+	resp->verbs_qp = cpu_to_be32(qp->remote_qpn);
+	rcu_read_unlock();
+
+	resp->aeth = rvt_compute_aeth(qp);
+	resp->verbs_psn = cpu_to_be32(mask_psn(flow->flow_state.ib_spsn +
+					       flow->pkt));
+
+	*bth0 = TID_OP(READ_RESP) << 24;
+	*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));
+	*last = last_pkt;
+	if (last_pkt)
+		/* Advance to next flow */
+		req->clear_tail = (req->clear_tail + 1) &
+				  (MAX_FLOWS - 1);
+
+	if (next_offset >= tidlen) {
+		flow->tid_offset = 0;
+		flow->tid_idx++;
+	} else {
+		flow->tid_offset = next_offset;
+	}
+
+	hdwords = sizeof(ohdr->u.tid_rdma.r_rsp) / sizeof(u32);
+
+done:
+	return hdwords;
+}
+
+static inline struct tid_rdma_request *
+find_tid_request(struct rvt_qp *qp, u32 psn, enum ib_wr_opcode opcode)
+	__must_hold(&qp->s_lock)
+{
+	struct rvt_swqe *wqe;
+	struct tid_rdma_request *req = NULL;
+	u32 i, end;
+
+	end = qp->s_cur + 1;
+	if (end == qp->s_size)
+		end = 0;
+	for (i = qp->s_acked; i != end;) {
+		wqe = rvt_get_swqe_ptr(qp, i);
+		if (cmp_psn(psn, wqe->psn) >= 0 &&
+		    cmp_psn(psn, wqe->lpsn) <= 0) {
+			if (wqe->wr.opcode == opcode)
+				req = wqe_to_tid_req(wqe);
+			break;
+		}
+		if (++i == qp->s_size)
+			i = 0;
+	}
+
+	return req;
+}
+
+void hfi1_rc_rcv_tid_rdma_read_resp(struct hfi1_packet *packet)
+{
+	/* HANDLER FOR TID RDMA READ RESPONSE packet (Requestor side */
+
+	/*
+	 * 1. Find matching SWQE
+	 * 2. Check that the entire segment has been read.
+	 * 3. Remove HFI1_S_WAIT_TID_RESP from s_flags.
+	 * 4. Free the TID flow resources.
+	 * 5. Kick the send engine (hfi1_schedule_send())
+	 */
+	struct ib_other_headers *ohdr = packet->ohdr;
+	struct rvt_qp *qp = packet->qp;
+	struct hfi1_qp_priv *priv = qp->priv;
+	struct hfi1_ctxtdata *rcd = packet->rcd;
+	struct tid_rdma_request *req;
+	struct tid_rdma_flow *flow;
+	u32 opcode, aeth;
+	bool fecn;
+	unsigned long flags;
+	u32 kpsn, ipsn;
+
+	trace_hfi1_sender_rcv_tid_read_resp(qp);
+	fecn = process_ecn(qp, packet);
+	kpsn = mask_psn(be32_to_cpu(ohdr->bth[2]));
+	aeth = be32_to_cpu(ohdr->u.tid_rdma.r_rsp.aeth);
+	opcode = (be32_to_cpu(ohdr->bth[0]) >> 24) & 0xff;
+
+	spin_lock_irqsave(&qp->s_lock, flags);
+	ipsn = mask_psn(be32_to_cpu(ohdr->u.tid_rdma.r_rsp.verbs_psn));
+	req = find_tid_request(qp, ipsn, IB_WR_TID_RDMA_READ);
+	if (unlikely(!req))
+		goto ack_op_err;
+
+	flow = &req->flows[req->clear_tail];
+	/* When header suppression is disabled */
+	if (cmp_psn(ipsn, flow->flow_state.ib_lpsn)) {
+		update_r_next_psn_fecn(packet, priv, rcd, flow, fecn);
+
+		if (cmp_psn(kpsn, flow->flow_state.r_next_psn))
+			goto ack_done;
+		flow->flow_state.r_next_psn = mask_psn(kpsn + 1);
+		/*
+		 * Copy the payload to destination buffer if this packet is
+		 * delivered as an eager packet due to RSM rule and FECN.
+		 * The RSM rule selects FECN bit in BTH and SH bit in
+		 * KDETH header and therefore will not match the last
+		 * packet of each segment that has SH bit cleared.
+		 */
+		if (fecn && packet->etype == RHF_RCV_TYPE_EAGER) {
+			struct rvt_sge_state ss;
+			u32 len;
+			u32 tlen = packet->tlen;
+			u16 hdrsize = packet->hlen;
+			u8 pad = packet->pad;
+			u8 extra_bytes = pad + packet->extra_byte +
+				(SIZE_OF_CRC << 2);
+			u32 pmtu = qp->pmtu;
+
+			if (unlikely(tlen != (hdrsize + pmtu + extra_bytes)))
+				goto ack_op_err;
+			len = restart_sge(&ss, req->e.swqe, ipsn, pmtu);
+			if (unlikely(len < pmtu))
+				goto ack_op_err;
+			rvt_copy_sge(qp, &ss, packet->payload, pmtu, false,
+				     false);
+			/* Raise the sw sequence check flag for next packet */
+			priv->s_flags |= HFI1_R_TID_SW_PSN;
+		}
+
+		goto ack_done;
+	}
+	flow->flow_state.r_next_psn = mask_psn(kpsn + 1);
+	req->ack_pending--;
+	priv->pending_tid_r_segs--;
+	qp->s_num_rd_atomic--;
+	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);
+	}
+	if (qp->s_flags & RVT_S_WAIT_RDMAR) {
+		qp->s_flags &= ~(RVT_S_WAIT_RDMAR | RVT_S_WAIT_ACK);
+		hfi1_schedule_send(qp);
+	}
+
+	trace_hfi1_ack(qp, ipsn);
+	trace_hfi1_tid_req_rcv_read_resp(qp, 0, req->e.swqe->wr.opcode,
+					 req->e.swqe->psn, req->e.swqe->lpsn,
+					 req);
+	trace_hfi1_tid_flow_rcv_read_resp(qp, req->clear_tail, flow);
+
+	/* Release the tid resources */
+	hfi1_kern_exp_rcv_clear(req);
+
+	if (!do_rc_ack(qp, aeth, ipsn, opcode, 0, rcd))
+		goto ack_done;
+
+	/* If not done yet, build next read request */
+	if (++req->comp_seg >= req->total_segs) {
+		priv->tid_r_comp++;
+		req->state = TID_REQUEST_COMPLETE;
+	}
+
+	/*
+	 * Clear the hw flow under two conditions:
+	 * 1. This request is a sync point and it is complete;
+	 * 2. Current request is completed and there are no more requests.
+	 */
+	if ((req->state == TID_REQUEST_SYNC &&
+	     req->comp_seg == req->cur_seg) ||
+	    priv->tid_r_comp == priv->tid_r_reqs) {
+		hfi1_kern_clear_hw_flow(priv->rcd, qp);
+		priv->s_flags &= ~HFI1_R_TID_SW_PSN;
+		if (req->state == TID_REQUEST_SYNC)
+			req->state = TID_REQUEST_ACTIVE;
+	}
+
+	hfi1_schedule_send(qp);
+	goto ack_done;
+
+ack_op_err:
+	/*
+	 * The test indicates that the send engine has finished its cleanup
+	 * after sending the request and it's now safe to put the QP into error
+	 * state. However, if the wqe queue is empty (qp->s_acked == qp->s_tail
+	 * == qp->s_head), it would be unsafe to complete the wqe pointed by
+	 * qp->s_acked here. Putting the qp into error state will safely flush
+	 * all remaining requests.
+	 */
+	if (qp->s_last == qp->s_acked)
+		rvt_error_qp(qp, IB_WC_WR_FLUSH_ERR);
+
+ack_done:
+	spin_unlock_irqrestore(&qp->s_lock, flags);
+}
+
+void hfi1_kern_read_tid_flow_free(struct rvt_qp *qp)
+	__must_hold(&qp->s_lock)
+{
+	u32 n = qp->s_acked;
+	struct rvt_swqe *wqe;
+	struct tid_rdma_request *req;
+	struct hfi1_qp_priv *priv = qp->priv;
+
+	lockdep_assert_held(&qp->s_lock);
+	/* Free any TID entries */
+	while (n != qp->s_tail) {
+		wqe = rvt_get_swqe_ptr(qp, n);
+		if (wqe->wr.opcode == IB_WR_TID_RDMA_READ) {
+			req = wqe_to_tid_req(wqe);
+			hfi1_kern_exp_rcv_clear_all(req);
+		}
+
+		if (++n == qp->s_size)
+			n = 0;
+	}
+	/* Free flow */
+	hfi1_kern_clear_hw_flow(priv->rcd, qp);
+}
+
+static bool tid_rdma_tid_err(struct hfi1_packet *packet, u8 rcv_type)
+{
+	struct rvt_qp *qp = packet->qp;
+
+	if (rcv_type >= RHF_RCV_TYPE_IB)
+		goto done;
+
+	spin_lock(&qp->s_lock);
+
+	/*
+	 * We've ran out of space in the eager buffer.
+	 * Eagerly received KDETH packets which require space in the
+	 * Eager buffer (packet that have payload) are TID RDMA WRITE
+	 * response packets. In this case, we have to re-transmit the
+	 * TID RDMA WRITE request.
+	 */
+	if (rcv_type == RHF_RCV_TYPE_EAGER) {
+		hfi1_restart_rc(qp, qp->s_last_psn + 1, 1);
+		hfi1_schedule_send(qp);
+	}
+
+	/* Since no payload is delivered, just drop the packet */
+	spin_unlock(&qp->s_lock);
+done:
+	return true;
+}
+
+static void restart_tid_rdma_read_req(struct hfi1_ctxtdata *rcd,
+				      struct rvt_qp *qp, struct rvt_swqe *wqe)
+{
+	struct tid_rdma_request *req;
+	struct tid_rdma_flow *flow;
+
+	/* Start from the right segment */
+	qp->r_flags |= RVT_R_RDMAR_SEQ;
+	req = wqe_to_tid_req(wqe);
+	flow = &req->flows[req->clear_tail];
+	hfi1_restart_rc(qp, flow->flow_state.ib_spsn, 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);
+	}
+}
+
+/*
+ * Handle the KDETH eflags for TID RDMA READ response.
+ *
+ * Return true if the last packet for a segment has been received and it is
+ * time to process the response normally; otherwise, return true.
+ *
+ * The caller must hold the packet->qp->r_lock and the rcu_read_lock.
+ */
+static bool handle_read_kdeth_eflags(struct hfi1_ctxtdata *rcd,
+				     struct hfi1_packet *packet, u8 rcv_type,
+				     u8 rte, u32 psn, u32 ibpsn)
+	__must_hold(&packet->qp->r_lock) __must_hold(RCU)
+{
+	struct hfi1_pportdata *ppd = rcd->ppd;
+	struct hfi1_devdata *dd = ppd->dd;
+	struct hfi1_ibport *ibp;
+	struct rvt_swqe *wqe;
+	struct tid_rdma_request *req;
+	struct tid_rdma_flow *flow;
+	u32 ack_psn;
+	struct rvt_qp *qp = packet->qp;
+	struct hfi1_qp_priv *priv = qp->priv;
+	bool ret = true;
+	int diff = 0;
+	u32 fpsn;
+
+	lockdep_assert_held(&qp->r_lock);
+	trace_hfi1_rsp_read_kdeth_eflags(qp, ibpsn);
+	trace_hfi1_sender_read_kdeth_eflags(qp);
+	trace_hfi1_tid_read_sender_kdeth_eflags(qp, 0);
+	spin_lock(&qp->s_lock);
+	/* If the psn is out of valid range, drop the packet */
+	if (cmp_psn(ibpsn, qp->s_last_psn) < 0 ||
+	    cmp_psn(ibpsn, qp->s_psn) > 0)
+		goto s_unlock;
+
+	/*
+	 * 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.
+	 */
+	ack_psn = ibpsn - 1;
+	wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
+	ibp = to_iport(qp->ibqp.device, qp->port_num);
+
+	/* Complete WQEs that the PSN finishes. */
+	while ((int)delta_psn(ack_psn, wqe->lpsn) >= 0) {
+		/*
+		 * If this request is a RDMA read or atomic, and the NACK is
+		 * for a later operation, this NACK NAKs the RDMA read or
+		 * atomic.
+		 */
+		if (wqe->wr.opcode == IB_WR_RDMA_READ ||
+		    wqe->wr.opcode == IB_WR_TID_RDMA_READ ||
+		    wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
+		    wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) {
+			/* Retry this request. */
+			if (!(qp->r_flags & RVT_R_RDMAR_SEQ)) {
+				qp->r_flags |= RVT_R_RDMAR_SEQ;
+				if (wqe->wr.opcode == IB_WR_TID_RDMA_READ) {
+					restart_tid_rdma_read_req(rcd, qp,
+								  wqe);
+				} else {
+					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(/* wait */
+						   &qp->rspwait,
+						   &rcd->qp_wait_list);
+					}
+				}
+			}
+			/*
+			 * No need to process the NAK since we are
+			 * restarting an earlier request.
+			 */
+			break;
+		}
+
+		wqe = do_rc_completion(qp, wqe, ibp);
+		if (qp->s_acked == qp->s_tail)
+			goto s_unlock;
+	}
+
+	if (qp->s_acked == qp->s_tail)
+		goto s_unlock;
+
+	/* Handle the eflags for the request */
+	if (wqe->wr.opcode != IB_WR_TID_RDMA_READ)
+		goto s_unlock;
+
+	req = wqe_to_tid_req(wqe);
+	trace_hfi1_tid_req_read_kdeth_eflags(qp, 0, wqe->wr.opcode, wqe->psn,
+					     wqe->lpsn, req);
+	switch (rcv_type) {
+	case RHF_RCV_TYPE_EXPECTED:
+		switch (rte) {
+		case RHF_RTE_EXPECTED_FLOW_SEQ_ERR:
+			/*
+			 * On the first occurrence of a Flow Sequence error,
+			 * the flag TID_FLOW_SW_PSN is set.
+			 *
+			 * After that, the flow is *not* reprogrammed and the
+			 * protocol falls back to SW PSN checking. This is done
+			 * to prevent continuous Flow Sequence errors for any
+			 * packets that could be still in the fabric.
+			 */
+			flow = &req->flows[req->clear_tail];
+			trace_hfi1_tid_flow_read_kdeth_eflags(qp,
+							      req->clear_tail,
+							      flow);
+			if (priv->s_flags & HFI1_R_TID_SW_PSN) {
+				diff = cmp_psn(psn,
+					       flow->flow_state.r_next_psn);
+				if (diff > 0) {
+					/* Drop the packet.*/
+					goto s_unlock;
+				} else if (diff < 0) {
+					/*
+					 * If a response packet for a restarted
+					 * request has come back, reset the
+					 * restart flag.
+					 */
+					if (qp->r_flags & RVT_R_RDMAR_SEQ)
+						qp->r_flags &=
+							~RVT_R_RDMAR_SEQ;
+
+					/* Drop the packet.*/
+					goto s_unlock;
+				}
+
+				/*
+				 * If SW PSN verification is successful and
+				 * this is the last packet in the segment, tell
+				 * the caller to process it as a normal packet.
+				 */
+				fpsn = full_flow_psn(flow,
+						     flow->flow_state.lpsn);
+				if (cmp_psn(fpsn, psn) == 0) {
+					ret = false;
+					if (qp->r_flags & RVT_R_RDMAR_SEQ)
+						qp->r_flags &=
+							~RVT_R_RDMAR_SEQ;
+				}
+				flow->flow_state.r_next_psn =
+					mask_psn(psn + 1);
+			} else {
+				u32 last_psn;
+
+				last_psn = read_r_next_psn(dd, rcd->ctxt,
+							   flow->idx);
+				flow->flow_state.r_next_psn = last_psn;
+				priv->s_flags |= HFI1_R_TID_SW_PSN;
+				/*
+				 * If no request has been restarted yet,
+				 * restart the current one.
+				 */
+				if (!(qp->r_flags & RVT_R_RDMAR_SEQ))
+					restart_tid_rdma_read_req(rcd, qp,
+								  wqe);
+			}
+
+			break;
+
+		case RHF_RTE_EXPECTED_FLOW_GEN_ERR:
+			/*
+			 * Since the TID flow is able to ride through
+			 * generation mismatch, drop this stale packet.
+			 */
+			break;
+
+		default:
+			break;
+		}
+		break;
+
+	case RHF_RCV_TYPE_ERROR:
+		switch (rte) {
+		case RHF_RTE_ERROR_OP_CODE_ERR:
+		case RHF_RTE_ERROR_KHDR_MIN_LEN_ERR:
+		case RHF_RTE_ERROR_KHDR_HCRC_ERR:
+		case RHF_RTE_ERROR_KHDR_KVER_ERR:
+		case RHF_RTE_ERROR_CONTEXT_ERR:
+		case RHF_RTE_ERROR_KHDR_TID_ERR:
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+s_unlock:
+	spin_unlock(&qp->s_lock);
+	return ret;
+}
+
+bool hfi1_handle_kdeth_eflags(struct hfi1_ctxtdata *rcd,
+			      struct hfi1_pportdata *ppd,
+			      struct hfi1_packet *packet)
+{
+	struct hfi1_ibport *ibp = &ppd->ibport_data;
+	struct hfi1_devdata *dd = ppd->dd;
+	struct rvt_dev_info *rdi = &dd->verbs_dev.rdi;
+	u8 rcv_type = rhf_rcv_type(packet->rhf);
+	u8 rte = rhf_rcv_type_err(packet->rhf);
+	struct ib_header *hdr = packet->hdr;
+	struct ib_other_headers *ohdr = NULL;
+	int lnh = be16_to_cpu(hdr->lrh[0]) & 3;
+	u16 lid  = be16_to_cpu(hdr->lrh[1]);
+	u8 opcode;
+	u32 qp_num, psn, ibpsn;
+	struct rvt_qp *qp;
+	struct hfi1_qp_priv *qpriv;
+	unsigned long flags;
+	bool ret = true;
+	struct rvt_ack_entry *e;
+	struct tid_rdma_request *req;
+	struct tid_rdma_flow *flow;
+	int diff = 0;
+
+	trace_hfi1_msg_handle_kdeth_eflags(NULL, "Kdeth error: rhf ",
+					   packet->rhf);
+	if (packet->rhf & RHF_ICRC_ERR)
+		return ret;
+
+	packet->ohdr = &hdr->u.oth;
+	ohdr = packet->ohdr;
+	trace_input_ibhdr(rcd->dd, packet, !!(rhf_dc_info(packet->rhf)));
+
+	/* Get the destination QP number. */
+	qp_num = be32_to_cpu(ohdr->u.tid_rdma.r_rsp.verbs_qp) &
+		RVT_QPN_MASK;
+	if (lid >= be16_to_cpu(IB_MULTICAST_LID_BASE))
+		goto drop;
+
+	psn = mask_psn(be32_to_cpu(ohdr->bth[2]));
+	opcode = (be32_to_cpu(ohdr->bth[0]) >> 24) & 0xff;
+
+	rcu_read_lock();
+	qp = rvt_lookup_qpn(rdi, &ibp->rvp, qp_num);
+	if (!qp)
+		goto rcu_unlock;
+
+	packet->qp = qp;
+
+	/* Check for valid receive state. */
+	spin_lock_irqsave(&qp->r_lock, flags);
+	if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK)) {
+		ibp->rvp.n_pkt_drops++;
+		goto r_unlock;
+	}
+
+	if (packet->rhf & RHF_TID_ERR) {
+		/* For TIDERR and RC QPs preemptively schedule a NAK */
+		u32 tlen = rhf_pkt_len(packet->rhf); /* in bytes */
+
+		/* Sanity check packet */
+		if (tlen < 24)
+			goto r_unlock;
+
+		/*
+		 * Check for GRH. We should never get packets with GRH in this
+		 * path.
+		 */
+		if (lnh == HFI1_LRH_GRH)
+			goto r_unlock;
+
+		if (tid_rdma_tid_err(packet, rcv_type))
+			goto r_unlock;
+	}
+
+	/* handle TID RDMA READ */
+	if (opcode == TID_OP(READ_RESP)) {
+		ibpsn = be32_to_cpu(ohdr->u.tid_rdma.r_rsp.verbs_psn);
+		ibpsn = mask_psn(ibpsn);
+		ret = handle_read_kdeth_eflags(rcd, packet, rcv_type, rte, psn,
+					       ibpsn);
+		goto r_unlock;
+	}
+
+	/*
+	 * qp->s_tail_ack_queue points to the rvt_ack_entry currently being
+	 * processed. These a completed sequentially so we can be sure that
+	 * the pointer will not change until the entire request has completed.
+	 */
+	spin_lock(&qp->s_lock);
+	qpriv = qp->priv;
+	if (qpriv->r_tid_tail == HFI1_QP_WQE_INVALID ||
+	    qpriv->r_tid_tail == qpriv->r_tid_head)
+		goto unlock;
+	e = &qp->s_ack_queue[qpriv->r_tid_tail];
+	if (e->opcode != TID_OP(WRITE_REQ))
+		goto unlock;
+	req = ack_to_tid_req(e);
+	if (req->comp_seg == req->cur_seg)
+		goto unlock;
+	flow = &req->flows[req->clear_tail];
+	trace_hfi1_eflags_err_write(qp, rcv_type, rte, psn);
+	trace_hfi1_rsp_handle_kdeth_eflags(qp, psn);
+	trace_hfi1_tid_write_rsp_handle_kdeth_eflags(qp);
+	trace_hfi1_tid_req_handle_kdeth_eflags(qp, 0, e->opcode, e->psn,
+					       e->lpsn, req);
+	trace_hfi1_tid_flow_handle_kdeth_eflags(qp, req->clear_tail, flow);
+
+	switch (rcv_type) {
+	case RHF_RCV_TYPE_EXPECTED:
+		switch (rte) {
+		case RHF_RTE_EXPECTED_FLOW_SEQ_ERR:
+			if (!(qpriv->s_flags & HFI1_R_TID_SW_PSN)) {
+				qpriv->s_flags |= HFI1_R_TID_SW_PSN;
+				flow->flow_state.r_next_psn =
+					read_r_next_psn(dd, rcd->ctxt,
+							flow->idx);
+				qpriv->r_next_psn_kdeth =
+					flow->flow_state.r_next_psn;
+				goto nak_psn;
+			} else {
+				/*
+				 * If the received PSN does not match the next
+				 * expected PSN, NAK the packet.
+				 * However, only do that if we know that the a
+				 * NAK has already been sent. Otherwise, this
+				 * mismatch could be due to packets that were
+				 * already in flight.
+				 */
+				diff = cmp_psn(psn,
+					       flow->flow_state.r_next_psn);
+				if (diff > 0)
+					goto nak_psn;
+				else if (diff < 0)
+					break;
+
+				qpriv->s_nak_state = 0;
+				/*
+				 * If SW PSN verification is successful and this
+				 * is the last packet in the segment, tell the
+				 * caller to process it as a normal packet.
+				 */
+				if (psn == full_flow_psn(flow,
+							 flow->flow_state.lpsn))
+					ret = false;
+				flow->flow_state.r_next_psn =
+					mask_psn(psn + 1);
+				qpriv->r_next_psn_kdeth =
+					flow->flow_state.r_next_psn;
+			}
+			break;
+
+		case RHF_RTE_EXPECTED_FLOW_GEN_ERR:
+			goto nak_psn;
+
+		default:
+			break;
+		}
+		break;
+
+	case RHF_RCV_TYPE_ERROR:
+		switch (rte) {
+		case RHF_RTE_ERROR_OP_CODE_ERR:
+		case RHF_RTE_ERROR_KHDR_MIN_LEN_ERR:
+		case RHF_RTE_ERROR_KHDR_HCRC_ERR:
+		case RHF_RTE_ERROR_KHDR_KVER_ERR:
+		case RHF_RTE_ERROR_CONTEXT_ERR:
+		case RHF_RTE_ERROR_KHDR_TID_ERR:
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+
+unlock:
+	spin_unlock(&qp->s_lock);
+r_unlock:
+	spin_unlock_irqrestore(&qp->r_lock, flags);
+rcu_unlock:
+	rcu_read_unlock();
+drop:
+	return ret;
+nak_psn:
+	ibp->rvp.n_rc_seqnak++;
+	if (!qpriv->s_nak_state) {
+		qpriv->s_nak_state = IB_NAK_PSN_ERROR;
+		/* We are NAK'ing the next expected PSN */
+		qpriv->s_nak_psn = mask_psn(flow->flow_state.r_next_psn);
+		tid_rdma_trigger_ack(qp);
+	}
+	goto unlock;
+}
+
+/*
+ * "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;
+	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) {
+		*bth2 = mask_psn(qp->s_psn);
+		flow = find_flow_ib(req, *bth2, &fidx);
+		if (!flow) {
+			trace_hfi1_msg_tid_restart_req(/* msg */
+			   qp, "!!!!!! Could not find flow to restart: bth2 ",
+			   (u64)*bth2);
+			trace_hfi1_tid_req_restart_req(qp, 0, wqe->wr.opcode,
+						       wqe->psn, wqe->lpsn,
+						       req);
+			return;
+		}
+	} else {
+		fidx = req->acked_tail;
+		flow = &req->flows[fidx];
+		*bth2 = mask_psn(req->r_ack_psn);
+	}
+
+	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));
+
+	trace_hfi1_tid_flow_restart_req(qp, fidx, flow);
+	diff = delta_pkts + flow->resync_npkts;
+
+	flow->sent = 0;
+	flow->pkt = 0;
+	flow->tid_idx = 0;
+	flow->tid_offset = 0;
+	if (diff) {
+		for (tididx = 0; tididx < flow->tidcnt; tididx++) {
+			u32 tidentry = flow->tid_entry[tididx], tidlen,
+				tidnpkts, npkts;
+
+			flow->tid_offset = 0;
+			tidlen = EXP_TID_GET(tidentry, LEN) * PAGE_SIZE;
+			tidnpkts = rvt_div_round_up_mtu(qp, tidlen);
+			npkts = min_t(u32, diff, tidnpkts);
+			flow->pkt += npkts;
+			flow->sent += (npkts == tidnpkts ? tidlen :
+				       npkts * qp->pmtu);
+			flow->tid_offset += npkts * qp->pmtu;
+			diff -= npkts;
+			if (!diff)
+				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->tid_entry[tididx], LEN) * PAGE_SIZE) {
+		tididx++;
+		flow->tid_offset = 0;
+	}
+	flow->tid_idx = tididx;
+	if (wqe->wr.opcode == IB_WR_TID_RDMA_READ)
+		/* Move flow_idx to correct index */
+		req->flow_idx = fidx;
+	else
+		req->clear_tail = fidx;
+
+	trace_hfi1_tid_flow_restart_req(qp, fidx, flow);
+	trace_hfi1_tid_req_restart_req(qp, 0, wqe->wr.opcode, wqe->psn,
+				       wqe->lpsn, req);
+	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, MAX_FLOWS);
+		i = qpriv->s_tid_tail;
+		do {
+			for (; CIRC_CNT(req->setup_head, fidx, MAX_FLOWS);
+			      fidx = CIRC_NEXT(fidx, 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_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);
+	}
+}
+
+bool hfi1_tid_rdma_wqe_interlock(struct rvt_qp *qp, struct rvt_swqe *wqe)
+{
+	struct rvt_swqe *prev;
+	struct hfi1_qp_priv *priv = qp->priv;
+	u32 s_prev;
+	struct tid_rdma_request *req;
+
+	s_prev = (qp->s_cur == 0 ? qp->s_size : qp->s_cur) - 1;
+	prev = rvt_get_swqe_ptr(qp, s_prev);
+
+	switch (wqe->wr.opcode) {
+	case IB_WR_SEND:
+	case IB_WR_SEND_WITH_IMM:
+	case IB_WR_SEND_WITH_INV:
+	case IB_WR_ATOMIC_CMP_AND_SWP:
+	case IB_WR_ATOMIC_FETCH_AND_ADD:
+	case IB_WR_RDMA_WRITE:
+	case IB_WR_RDMA_WRITE_WITH_IMM:
+		switch (prev->wr.opcode) {
+		case IB_WR_TID_RDMA_WRITE:
+			req = wqe_to_tid_req(prev);
+			if (req->ack_seg != req->total_segs)
+				goto interlock;
+			break;
+		default:
+			break;
+		}
+		break;
+	case IB_WR_RDMA_READ:
+		if (prev->wr.opcode != IB_WR_TID_RDMA_WRITE)
+			break;
+		fallthrough;
+	case IB_WR_TID_RDMA_READ:
+		switch (prev->wr.opcode) {
+		case IB_WR_RDMA_READ:
+			if (qp->s_acked != qp->s_cur)
+				goto interlock;
+			break;
+		case IB_WR_TID_RDMA_WRITE:
+			req = wqe_to_tid_req(prev);
+			if (req->ack_seg != req->total_segs)
+				goto interlock;
+			break;
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+	return false;
+
+interlock:
+	priv->s_flags |= HFI1_S_TID_WAIT_INTERLCK;
+	return true;
+}
+
+/* Does @sge meet the alignment requirements for tid rdma? */
+static inline bool hfi1_check_sge_align(struct rvt_qp *qp,
+					struct rvt_sge *sge, int num_sge)
+{
+	int i;
+
+	for (i = 0; i < num_sge; i++, sge++) {
+		trace_hfi1_sge_check_align(qp, i, sge);
+		if ((u64)sge->vaddr & ~PAGE_MASK ||
+		    sge->sge_length & ~PAGE_MASK)
+			return false;
+	}
+	return true;
+}
+
+void setup_tid_rdma_wqe(struct rvt_qp *qp, struct rvt_swqe *wqe)
+{
+	struct hfi1_qp_priv *qpriv = (struct hfi1_qp_priv *)qp->priv;
+	struct hfi1_swqe_priv *priv = wqe->priv;
+	struct tid_rdma_params *remote;
+	enum ib_wr_opcode new_opcode;
+	bool do_tid_rdma = false;
+	struct hfi1_pportdata *ppd = qpriv->rcd->ppd;
+
+	if ((rdma_ah_get_dlid(&qp->remote_ah_attr) & ~((1 << ppd->lmc) - 1)) ==
+				ppd->lid)
+		return;
+	if (qpriv->hdr_type != HFI1_PKT_TYPE_9B)
+		return;
+
+	rcu_read_lock();
+	remote = rcu_dereference(qpriv->tid_rdma.remote);
+	/*
+	 * If TID RDMA is disabled by the negotiation, don't
+	 * use it.
+	 */
+	if (!remote)
+		goto exit;
+
+	if (wqe->wr.opcode == IB_WR_RDMA_READ) {
+		if (hfi1_check_sge_align(qp, &wqe->sg_list[0],
+					 wqe->wr.num_sge)) {
+			new_opcode = IB_WR_TID_RDMA_READ;
+			do_tid_rdma = true;
+		}
+	} else if (wqe->wr.opcode == IB_WR_RDMA_WRITE) {
+		/*
+		 * TID RDMA is enabled for this RDMA WRITE request iff:
+		 *   1. The remote address is page-aligned,
+		 *   2. The length is larger than the minimum segment size,
+		 *   3. The length is page-multiple.
+		 */
+		if (!(wqe->rdma_wr.remote_addr & ~PAGE_MASK) &&
+		    !(wqe->length & ~PAGE_MASK)) {
+			new_opcode = IB_WR_TID_RDMA_WRITE;
+			do_tid_rdma = true;
+		}
+	}
+
+	if (do_tid_rdma) {
+		if (hfi1_kern_exp_rcv_alloc_flows(&priv->tid_req, GFP_ATOMIC))
+			goto exit;
+		wqe->wr.opcode = new_opcode;
+		priv->tid_req.seg_len =
+			min_t(u32, remote->max_len, wqe->length);
+		priv->tid_req.total_segs =
+			DIV_ROUND_UP(wqe->length, priv->tid_req.seg_len);
+		/* Compute the last PSN of the request */
+		wqe->lpsn = wqe->psn;
+		if (wqe->wr.opcode == IB_WR_TID_RDMA_READ) {
+			priv->tid_req.n_flows = remote->max_read;
+			qpriv->tid_r_reqs++;
+			wqe->lpsn += rvt_div_round_up_mtu(qp, wqe->length) - 1;
+		} else {
+			wqe->lpsn += priv->tid_req.total_segs - 1;
+			atomic_inc(&qpriv->n_requests);
+		}
+
+		priv->tid_req.cur_seg = 0;
+		priv->tid_req.comp_seg = 0;
+		priv->tid_req.ack_seg = 0;
+		priv->tid_req.state = TID_REQUEST_INACTIVE;
+		/*
+		 * Reset acked_tail.
+		 * TID RDMA READ does not have ACKs so it does not
+		 * update the pointer. We have to reset it so TID RDMA
+		 * WRITE does not get confused.
+		 */
+		priv->tid_req.acked_tail = priv->tid_req.setup_head;
+		trace_hfi1_tid_req_setup_tid_wqe(qp, 1, wqe->wr.opcode,
+						 wqe->psn, wqe->lpsn,
+						 &priv->tid_req);
+	}
+exit:
+	rcu_read_unlock();
+}
+
+/* TID RDMA WRITE functions */
+
+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)
+{
+	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);
+}
+
+static u32 hfi1_compute_tid_rdma_flow_wt(struct rvt_qp *qp)
+{
+	/*
+	 * Heuristic for computing the RNR timeout when waiting on the flow
+	 * queue. Rather than a computationaly expensive exact estimate of when
+	 * a flow will be available, we assume that if a QP is at position N in
+	 * the flow queue it has to wait approximately (N + 1) * (number of
+	 * segments between two sync points). The rationale for this is that
+	 * flows are released and recycled at each sync point.
+	 */
+	return (MAX_TID_FLOW_PSN * qp->pmtu) >> TID_RDMA_SEGMENT_SHIFT;
+}
+
+static u32 position_in_queue(struct hfi1_qp_priv *qpriv,
+			     struct tid_queue *queue)
+{
+	return qpriv->tid_enqueue - queue->dequeue;
+}
+
+/*
+ * @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;
+}
+
+/*
+ * 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 up to 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) {
+		trace_hfi1_rsp_tid_write_alloc_res(qp, 0);
+		trace_hfi1_tid_write_rsp_alloc_res(qp);
+		/*
+		 * 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);
+				qpriv->s_flags &= ~HFI1_R_TID_SW_PSN;
+			}
+			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);
+		trace_hfi1_tid_req_write_alloc_res(qp, 0, e->opcode, e->psn,
+						   e->lpsn, req);
+		/* 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;
+			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 = hfi1_compute_tid_rdma_flow_wt(qp) *
+					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 by a delay in scheduling the second leg which we
+		 * cannot estimate, we use a rather arbitrary RNR timeout of
+		 * (MAX_FLOWS / 2) segments
+		 */
+		if (!CIRC_SPACE(req->setup_head, req->acked_tail,
+				MAX_FLOWS)) {
+			ret = -EAGAIN;
+			to_seg = MAX_FLOWS >> 1;
+			tid_rdma_trigger_ack(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:
+	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);
+
+	trace_hfi1_rsp_tid_write_alloc_res(qp, qp->r_psn);
+	/*
+	 * 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 fecn;
+	u8 next;
+	u64 vaddr;
+	int diff;
+
+	bth0 = be32_to_cpu(ohdr->bth[0]);
+	if (hfi1_ruc_check_hdr(ibp, packet))
+		return;
+
+	fecn = process_ecn(qp, packet);
+	psn = mask_psn(be32_to_cpu(ohdr->bth[2]));
+	trace_hfi1_rsp_rcv_tid_write_req(qp, psn);
+
+	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)) {
+		tid_rdma_rcv_err(packet, ohdr, qp, psn, diff, fecn);
+		return;
+	}
+
+	/*
+	 * 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;
+	}
+
+	release_rdma_sge_mr(e);
+
+	/* 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++;
+
+	trace_hfi1_tid_req_rcv_write_req(qp, 0, e->opcode, e->psn, e->lpsn,
+					 req);
+
+	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);
+	trace_hfi1_tid_write_rsp_rcv_req(qp);
+
+	/* Schedule the send tasklet. */
+	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;
+
+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;
+}
+
+u32 hfi1_build_tid_rdma_write_resp(struct rvt_qp *qp, struct rvt_ack_entry *e,
+				   struct ib_other_headers *ohdr, u32 *bth1,
+				   u32 bth2, u32 *len,
+				   struct rvt_sge_state **ss)
+{
+	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;
+
+	trace_hfi1_tid_req_build_write_resp(qp, 0, e->opcode, e->psn, e->lpsn,
+					    req);
+	trace_hfi1_tid_write_rsp_build_resp(qp);
+	trace_hfi1_rsp_build_tid_write_resp(qp, bth2);
+	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;
+		trace_hfi1_tid_flow_build_write_resp(qp, req->flow_idx, flow);
+		req->flow_idx = CIRC_NEXT(req->flow_idx, MAX_FLOWS);
+		hfi1_add_tid_reap_timer(qp);
+		break;
+
+	case TID_REQUEST_RESEND_ACTIVE:
+	case TID_REQUEST_RESEND:
+		trace_hfi1_tid_flow_build_write_resp(qp, req->flow_idx, flow);
+		req->flow_idx = CIRC_NEXT(req->flow_idx, MAX_FLOWS);
+		if (!CIRC_CNT(req->setup_head, req->flow_idx, 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->tid_entry;
+	resp_len = sizeof(*flow->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;
+}
+
+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;
+}
+
+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__);
+		trace_hfi1_msg_tid_timeout(/* msg */
+			qp, "resource timeout = ",
+			(u64)qpriv->tid_timer_timeout_jiffies);
+		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);
+}
+
+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
+	 * 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 fecn;
+	unsigned long flags;
+
+	fecn = process_ecn(qp, packet);
+	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. */
+	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, 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->pkt = 0;
+	flow->tid_idx = 0;
+	flow->tid_offset = 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);
+	if (pktlen > sizeof(flow->tid_entry)) {
+		status = IB_WC_LOC_LEN_ERR;
+		goto ack_err;
+	}
+	memcpy(flow->tid_entry, packet->ebuf, pktlen);
+	flow->tidcnt = pktlen / sizeof(*flow->tid_entry);
+	trace_hfi1_tid_flow_rcv_write_resp(qp, req->setup_head, flow);
+
+	req->comp_seg++;
+	trace_hfi1_tid_write_sender_rcv_resp(qp, 0);
+	/*
+	 * Walk the TID_ENTRY list to make sure we have enough space for a
+	 * complete segment.
+	 */
+	for (i = 0; i < flow->tidcnt; i++) {
+		trace_hfi1_tid_entry_rcv_write_resp(/* entry */
+			qp, i, flow->tid_entry[i]);
+		if (!EXP_TID_GET(flow->tid_entry[i], LEN)) {
+			status = IB_WC_LOC_LEN_ERR;
+			goto ack_err;
+		}
+		tidlen += EXP_TID_GET(flow->tid_entry[i], LEN);
+	}
+	if (tidlen * PAGE_SIZE < flow->length) {
+		status = IB_WC_LOC_LEN_ERR;
+		goto ack_err;
+	}
+
+	trace_hfi1_tid_req_rcv_write_resp(qp, 0, wqe->wr.opcode, wqe->psn,
+					  wqe->lpsn, req);
+	/*
+	 * 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, 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:
+	if (fecn)
+		qp->s_flags |= RVT_S_ECN;
+	spin_unlock_irqrestore(&qp->s_lock, flags);
+}
+
+bool hfi1_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->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_trdma_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);
+	trace_hfi1_tid_entry_build_write_data(qp, flow->tid_idx, tidentry);
+	trace_hfi1_tid_flow_build_write_data(qp, req->clear_tail, flow);
+
+	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;
+}
+
+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;
+	bool fecn;
+
+	fecn = process_ecn(qp, packet);
+	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))) {
+		update_r_next_psn_fecn(packet, priv, rcd, flow, fecn);
+
+		if (cmp_psn(psn, flow->flow_state.r_next_psn))
+			goto send_nak;
+
+		flow->flow_state.r_next_psn = mask_psn(psn + 1);
+		/*
+		 * Copy the payload to destination buffer if this packet is
+		 * delivered as an eager packet due to RSM rule and FECN.
+		 * The RSM rule selects FECN bit in BTH and SH bit in
+		 * KDETH header and therefore will not match the last
+		 * packet of each segment that has SH bit cleared.
+		 */
+		if (fecn && packet->etype == RHF_RCV_TYPE_EAGER) {
+			struct rvt_sge_state ss;
+			u32 len;
+			u32 tlen = packet->tlen;
+			u16 hdrsize = packet->hlen;
+			u8 pad = packet->pad;
+			u8 extra_bytes = pad + packet->extra_byte +
+				(SIZE_OF_CRC << 2);
+			u32 pmtu = qp->pmtu;
+
+			if (unlikely(tlen != (hdrsize + pmtu + extra_bytes)))
+				goto send_nak;
+			len = req->comp_seg * req->seg_len;
+			len += delta_psn(psn,
+				full_flow_psn(flow, flow->flow_state.spsn)) *
+				pmtu;
+			if (unlikely(req->total_len - len < pmtu))
+				goto send_nak;
+
+			/*
+			 * The e->rdma_sge field is set when TID RDMA WRITE REQ
+			 * is first received and is never modified thereafter.
+			 */
+			ss.sge = e->rdma_sge;
+			ss.sg_list = NULL;
+			ss.num_sge = 1;
+			ss.total_len = req->total_len;
+			rvt_skip_sge(&ss, len, false);
+			rvt_copy_sge(qp, &ss, packet->payload, pmtu, false,
+				     false);
+			/* Raise the sw sequence check flag for next packet */
+			priv->r_next_psn_kdeth = mask_psn(psn + 1);
+			priv->s_flags |= HFI1_R_TID_SW_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.
+	 */
+	trace_hfi1_rsp_rcv_tid_write_data(qp, psn);
+	trace_hfi1_tid_req_rcv_write_data(qp, 0, e->opcode, e->psn, e->lpsn,
+					  req);
+	trace_hfi1_tid_write_rsp_rcv_data(qp);
+	validate_r_tid_ack(priv);
+
+	if (opcode == TID_OP(WRITE_DATA_LAST)) {
+		release_rdma_sge_mr(e);
+		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:
+	tid_rdma_schedule_ack(qp);
+exit:
+	priv->r_next_psn_kdeth = flow->flow_state.r_next_psn;
+	if (fecn)
+		qp->s_flags |= RVT_S_ECN;
+	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;
+		tid_rdma_trigger_ack(qp);
+	}
+	goto done;
+}
+
+static bool hfi1_tid_rdma_is_resync_psn(u32 psn)
+{
+	return (bool)((psn & HFI1_KDETH_BTH_SEQ_MASK) ==
+		      HFI1_KDETH_BTH_SEQ_MASK);
+}
+
+u32 hfi1_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);
+}
+
+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, flpsn, resync_psn, ack_kpsn;
+	unsigned long flags;
+	u16 fidx;
+
+	trace_hfi1_tid_write_sender_rcv_tid_ack(qp, 0);
+	process_ecn(qp, packet);
+	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);
+	trace_hfi1_rcv_tid_ack(qp, aeth, psn, req_psn, resync_psn);
+
+	/* 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--;
+	}
+
+	if (unlikely(qp->s_acked == qp->s_tail))
+		goto ack_op_err;
+
+	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);
+	trace_hfi1_tid_req_rcv_tid_ack(qp, 0, wqe->wr.opcode, wqe->psn,
+				       wqe->lpsn, req);
+	flow = &req->flows[req->acked_tail];
+	trace_hfi1_tid_flow_rcv_tid_ack(qp, req->acked_tail, flow);
+
+	/* Drop stale ACK/NAK */
+	if (cmp_psn(psn, full_flow_psn(flow, flow->flow_state.spsn)) < 0 ||
+	    cmp_psn(req_psn, flow->flow_state.resp_ib_psn) < 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, MAX_FLOWS);
+		req->r_last_acked = flow->flow_state.resp_ib_psn;
+		trace_hfi1_tid_req_rcv_tid_ack(qp, 0, wqe->wr.opcode, wqe->psn,
+					       wqe->lpsn, req);
+		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));
+			trace_hfi1_sender_rcv_tid_ack(qp);
+			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];
+		trace_hfi1_tid_flow_rcv_tid_ack(qp, req->acked_tail, flow);
+	}
+
+	trace_hfi1_tid_req_rcv_tid_ack(qp, 0, wqe->wr.opcode, wqe->psn,
+				       wqe->lpsn, req);
+	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;
+			/*
+			 * If resync_psn points to the last flow PSN for a
+			 * segment and the new segment (likely from a new
+			 * request) starts with a new generation number, we
+			 * need to adjust resync_psn accordingly.
+			 */
+			if (flow->flow_state.generation !=
+			    (resync_psn >> HFI1_KDETH_BTH_SEQ_SHIFT))
+				resync_psn = mask_psn(fpsn - 1);
+			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,
+					      MAX_FLOWS);
+				     fidx = CIRC_NEXT(fidx, 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;
+					trace_hfi1_tid_flow_rcv_tid_ack(qp,
+									fidx,
+									flow);
+				}
+				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 */
+			if (!req->flows)
+				break;
+			flow = &req->flows[req->acked_tail];
+			flpsn = full_flow_psn(flow, flow->flow_state.lpsn);
+			if (cmp_psn(psn, flpsn) > 0)
+				break;
+			trace_hfi1_tid_flow_rcv_tid_ack(qp, req->acked_tail,
+							flow);
+			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);
+}
+
+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 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);
+	trace_hfi1_tid_write_sender_retry_timeout(qp, 0);
+	if (priv->s_flags & HFI1_S_TID_RETRY_TIMER) {
+		hfi1_stop_tid_retry_timer(qp);
+		if (!priv->s_retry) {
+			trace_hfi1_msg_tid_retry_timeout(/* msg */
+				qp,
+				"Exhausted retries. Tid retry timeout = ",
+				(u64)priv->tid_retry_timeout_jiffies);
+
+			wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
+			hfi1_trdma_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);
+			trace_hfi1_tid_req_tid_retry_timeout(/* req */
+			   qp, 0, wqe->wr.opcode, wqe->psn, wqe->lpsn, req);
+
+			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);
+}
+
+u32 hfi1_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);
+}
+
+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 fecn;
+	unsigned long flags;
+
+	fecn = process_ecn(qp, packet);
+	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;
+	trace_hfi1_tid_write_rsp_rcv_resync(qp);
+
+	/*
+	 * 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);
+			trace_hfi1_tid_req_rcv_resync(qp, 0, e->opcode, e->psn,
+						      e->lpsn, req);
+
+			/* start from last unacked segment */
+			for (flow_idx = req->clear_tail;
+			     CIRC_CNT(req->setup_head, flow_idx,
+				      MAX_FLOWS);
+			     flow_idx = CIRC_NEXT(flow_idx, 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;
+				trace_hfi1_tid_flow_rcv_resync(qp, flow_idx,
+							       flow);
+			}
+		}
+		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;
+	tid_rdma_trigger_ack(qp);
+bail:
+	if (fecn)
+		qp->s_flags |= RVT_S_ECN;
+	spin_unlock_irqrestore(&qp->s_lock, flags);
+}
+
+/*
+ * 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);
+}
+
+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);
+	trace_hfi1_tid_write_sender_make_tid_pkt(qp, 0);
+	/*
+	 * 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;
+
+	/*
+	 * Bail out if we can't send data.
+	 * Be reminded that this check must been done after the call to
+	 * make_tid_rdma_ack() because the responding QP could be in
+	 * RTR state where it can send TID RDMA ACK, not TID RDMA WRITE DATA.
+	 */
+	if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_SEND_OK))
+		goto bail;
+
+	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);
+	trace_hfi1_tid_req_make_tid_pkt(qp, 0, wqe->wr.opcode, wqe->psn,
+					wqe->lpsn, req);
+	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);
+		fallthrough;
+
+	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.
+		 */
+		trace_hfi1_sender_make_tid_pkt(qp);
+		trace_hfi1_tid_write_sender_make_tid_pkt(qp, 0);
+		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;
+
+		trace_hfi1_tid_req_make_tid_pkt(qp, 0, wqe->wr.opcode,
+						wqe->psn, wqe->lpsn, req);
+		last = hfi1_build_tid_rdma_packet(wqe, ohdr, &bth1, &bth2,
+						  &len);
+
+		if (last) {
+			/* move pointer to next flow */
+			req->clear_tail = CIRC_NEXT(req->clear_tail,
+						    MAX_FLOWS);
+			if (++req->cur_seg < req->total_segs) {
+				if (!CIRC_CNT(req->setup_head, req->clear_tail,
+					      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):
+		trace_hfi1_sender_make_tid_pkt(qp);
+		/* 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 += hfi1_build_tid_rdma_resync(qp, wqe, ohdr, &bth1,
+						     &bth2,
+						     CIRC_PREV(req->setup_head,
+							       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;
+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 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;
+}
+
+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;
+
+	trace_hfi1_tid_write_rsp_make_tid_ack(qp);
+	/* 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);
+	}
+
+	trace_hfi1_rsp_make_tid_ack(qp, e->psn);
+	trace_hfi1_tid_req_make_tid_ack(qp, 0, e->opcode, e->psn, e->lpsn,
+					req);
+	/*
+	 * 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,
+				 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, 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;
+
+	trace_hfi1_tid_write_rsp_make_tid_ack(qp);
+	trace_hfi1_tid_req_make_tid_ack(qp, 0, e->opcode, e->psn, e->lpsn,
+					req);
+	hwords += hfi1_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);
+	ps->s_txreq->txreq.flags |= SDMA_TXREQ_F_VIP;
+	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;
+}
+
+static int hfi1_send_tid_ok(struct rvt_qp *qp)
+{
+	struct hfi1_qp_priv *priv = qp->priv;
+
+	return !(priv->s_flags & RVT_S_BUSY ||
+		 qp->s_flags & HFI1_S_ANY_WAIT_IO) &&
+		(verbs_txreq_queued(iowait_get_tid_work(&priv->s_iowait)) ||
+		 (priv->s_flags & RVT_S_RESP_PENDING) ||
+		 !(qp->s_flags & HFI1_S_ANY_TID_WAIT_SEND));
+}
+
+void _hfi1_do_tid_send(struct work_struct *work)
+{
+	struct iowait_work *w = container_of(work, struct iowait_work, iowork);
+	struct rvt_qp *qp = iowait_to_qp(w->iow);
+
+	hfi1_do_tid_send(qp);
+}
+
+static void hfi1_do_tid_send(struct rvt_qp *qp)
+{
+	struct hfi1_pkt_state ps;
+	struct hfi1_qp_priv *priv = qp->priv;
+
+	ps.dev = to_idev(qp->ibqp.device);
+	ps.ibp = to_iport(qp->ibqp.device, qp->port_num);
+	ps.ppd = ppd_from_ibp(ps.ibp);
+	ps.wait = iowait_get_tid_work(&priv->s_iowait);
+	ps.in_thread = false;
+	ps.timeout_int = qp->timeout_jiffies / 8;
+
+	trace_hfi1_rc_do_tid_send(qp, false);
+	spin_lock_irqsave(&qp->s_lock, ps.flags);
+
+	/* Return if we are already busy processing a work request. */
+	if (!hfi1_send_tid_ok(qp)) {
+		if (qp->s_flags & HFI1_S_ANY_WAIT_IO)
+			iowait_set_flag(&priv->s_iowait, IOWAIT_PENDING_TID);
+		spin_unlock_irqrestore(&qp->s_lock, ps.flags);
+		return;
+	}
+
+	priv->s_flags |= RVT_S_BUSY;
+
+	ps.timeout = jiffies + ps.timeout_int;
+	ps.cpu = priv->s_sde ? priv->s_sde->cpu :
+		cpumask_first(cpumask_of_node(ps.ppd->dd->node));
+	ps.pkts_sent = false;
+
+	/* insure a pre-built packet is handled  */
+	ps.s_txreq = get_waiting_verbs_txreq(ps.wait);
+	do {
+		/* Check for a constructed packet to be sent. */
+		if (ps.s_txreq) {
+			if (priv->s_flags & HFI1_S_TID_BUSY_SET) {
+				qp->s_flags |= RVT_S_BUSY;
+				ps.wait = iowait_get_ib_work(&priv->s_iowait);
+			}
+			spin_unlock_irqrestore(&qp->s_lock, ps.flags);
+
+			/*
+			 * If the packet cannot be sent now, return and
+			 * the send tasklet will be woken up later.
+			 */
+			if (hfi1_verbs_send(qp, &ps))
+				return;
+
+			/* allow other tasks to run */
+			if (hfi1_schedule_send_yield(qp, &ps, true))
+				return;
+
+			spin_lock_irqsave(&qp->s_lock, ps.flags);
+			if (priv->s_flags & HFI1_S_TID_BUSY_SET) {
+				qp->s_flags &= ~RVT_S_BUSY;
+				priv->s_flags &= ~HFI1_S_TID_BUSY_SET;
+				ps.wait = iowait_get_tid_work(&priv->s_iowait);
+				if (iowait_flag_set(&priv->s_iowait,
+						    IOWAIT_PENDING_IB))
+					hfi1_schedule_send(qp);
+			}
+		}
+	} while (hfi1_make_tid_rdma_pkt(qp, &ps));
+	iowait_starve_clear(ps.pkts_sent, &priv->s_iowait);
+	spin_unlock_irqrestore(&qp->s_lock, ps.flags);
+}
+
+static bool _hfi1_schedule_tid_send(struct rvt_qp *qp)
+{
+	struct hfi1_qp_priv *priv = qp->priv;
+	struct hfi1_ibport *ibp =
+		to_iport(qp->ibqp.device, qp->port_num);
+	struct hfi1_pportdata *ppd = ppd_from_ibp(ibp);
+	struct hfi1_devdata *dd = ppd->dd;
+
+	if ((dd->flags & HFI1_SHUTDOWN))
+		return true;
+
+	return iowait_tid_schedule(&priv->s_iowait, ppd->hfi1_wq,
+				   priv->s_sde ?
+				   priv->s_sde->cpu :
+				   cpumask_first(cpumask_of_node(dd->node)));
+}
+
+/**
+ * hfi1_schedule_tid_send - schedule progress on TID RDMA state machine
+ * @qp: the QP
+ *
+ * This schedules qp progress on the TID RDMA state machine. Caller
+ * should hold the s_lock.
+ * Unlike hfi1_schedule_send(), this cannot use hfi1_send_ok() because
+ * the two state machines can step on each other with respect to the
+ * RVT_S_BUSY flag.
+ * Therefore, a modified test is used.
+ * @return true if the second leg is scheduled;
+ *  false if the second leg is not scheduled.
+ */
+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.
+		 */
+		_hfi1_schedule_tid_send(qp);
+		return true;
+	}
+	if (qp->s_flags & HFI1_S_ANY_WAIT_IO)
+		iowait_set_flag(&((struct hfi1_qp_priv *)qp->priv)->s_iowait,
+				IOWAIT_PENDING_TID);
+	return false;
+}
+
+bool hfi1_tid_rdma_ack_interlock(struct rvt_qp *qp, struct rvt_ack_entry *e)
+{
+	struct rvt_ack_entry *prev;
+	struct tid_rdma_request *req;
+	struct hfi1_ibdev *dev = to_idev(qp->ibqp.device);
+	struct hfi1_qp_priv *priv = qp->priv;
+	u32 s_prev;
+
+	s_prev = qp->s_tail_ack_queue == 0 ? rvt_size_atomic(&dev->rdi) :
+		(qp->s_tail_ack_queue - 1);
+	prev = &qp->s_ack_queue[s_prev];
+
+	if ((e->opcode == TID_OP(READ_REQ) ||
+	     e->opcode == OP(RDMA_READ_REQUEST)) &&
+	    prev->opcode == TID_OP(WRITE_REQ)) {
+		req = ack_to_tid_req(prev);
+		if (req->ack_seg != req->total_segs) {
+			priv->s_flags |= HFI1_R_TID_WAIT_INTERLCK;
+			return true;
+		}
+	}
+	return false;
+}
+
+static u32 read_r_next_psn(struct hfi1_devdata *dd, u8 ctxt, u8 fidx)
+{
+	u64 reg;
+
+	/*
+	 * The only sane way to get the amount of
+	 * progress is to read the HW flow state.
+	 */
+	reg = read_uctxt_csr(dd, ctxt, RCV_TID_FLOW_TABLE + (8 * fidx));
+	return mask_psn(reg);
+}
+
+static void tid_rdma_rcv_err(struct hfi1_packet *packet,
+			     struct ib_other_headers *ohdr,
+			     struct rvt_qp *qp, u32 psn, int diff, bool fecn)
+{
+	unsigned long flags;
+
+	tid_rdma_rcv_error(packet, ohdr, qp, psn, diff);
+	if (fecn) {
+		spin_lock_irqsave(&qp->s_lock, flags);
+		qp->s_flags |= RVT_S_ECN;
+		spin_unlock_irqrestore(&qp->s_lock, flags);
+	}
+}
+
+static void update_r_next_psn_fecn(struct hfi1_packet *packet,
+				   struct hfi1_qp_priv *priv,
+				   struct hfi1_ctxtdata *rcd,
+				   struct tid_rdma_flow *flow,
+				   bool fecn)
+{
+	/*
+	 * If a start/middle packet is delivered here due to
+	 * RSM rule and FECN, we need to update the r_next_psn.
+	 */
+	if (fecn && packet->etype == RHF_RCV_TYPE_EAGER &&
+	    !(priv->s_flags & HFI1_R_TID_SW_PSN)) {
+		struct hfi1_devdata *dd = rcd->dd;
+
+		flow->flow_state.r_next_psn =
+			read_r_next_psn(dd, rcd->ctxt, flow->idx);
+	}
+}