Adding upstream version 6.1.76.upstream/6.1.76

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

1 files changed, 832 insertions, 0 deletions

diff --git a/drivers/infiniband/sw/rxe/rxe_req.c b/drivers/infiniband/sw/rxe/rxe_req.c
new file mode 100644
index 000000000..2ace1007a
--- /dev/null
+++ b/drivers/infiniband/sw/rxe/rxe_req.c
@@ -0,0 +1,832 @@
+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+/*
+ * Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
+ * Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
+ */
+
+#include <linux/skbuff.h>
+#include <crypto/hash.h>
+
+#include "rxe.h"
+#include "rxe_loc.h"
+#include "rxe_queue.h"
+
+static int next_opcode(struct rxe_qp *qp, struct rxe_send_wqe *wqe,
+		       u32 opcode);
+
+static inline void retry_first_write_send(struct rxe_qp *qp,
+					  struct rxe_send_wqe *wqe, int npsn)
+{
+	int i;
+
+	for (i = 0; i < npsn; i++) {
+		int to_send = (wqe->dma.resid > qp->mtu) ?
+				qp->mtu : wqe->dma.resid;
+
+		qp->req.opcode = next_opcode(qp, wqe,
+					     wqe->wr.opcode);
+
+		if (wqe->wr.send_flags & IB_SEND_INLINE) {
+			wqe->dma.resid -= to_send;
+			wqe->dma.sge_offset += to_send;
+		} else {
+			advance_dma_data(&wqe->dma, to_send);
+		}
+	}
+}
+
+static void req_retry(struct rxe_qp *qp)
+{
+	struct rxe_send_wqe *wqe;
+	unsigned int wqe_index;
+	unsigned int mask;
+	int npsn;
+	int first = 1;
+	struct rxe_queue *q = qp->sq.queue;
+	unsigned int cons;
+	unsigned int prod;
+
+	cons = queue_get_consumer(q, QUEUE_TYPE_FROM_CLIENT);
+	prod = queue_get_producer(q, QUEUE_TYPE_FROM_CLIENT);
+
+	qp->req.wqe_index	= cons;
+	qp->req.psn		= qp->comp.psn;
+	qp->req.opcode		= -1;
+
+	for (wqe_index = cons; wqe_index != prod;
+			wqe_index = queue_next_index(q, wqe_index)) {
+		wqe = queue_addr_from_index(qp->sq.queue, wqe_index);
+		mask = wr_opcode_mask(wqe->wr.opcode, qp);
+
+		if (wqe->state == wqe_state_posted)
+			break;
+
+		if (wqe->state == wqe_state_done)
+			continue;
+
+		wqe->iova = (mask & WR_ATOMIC_MASK) ?
+			     wqe->wr.wr.atomic.remote_addr :
+			     (mask & WR_READ_OR_WRITE_MASK) ?
+			     wqe->wr.wr.rdma.remote_addr :
+			     0;
+
+		if (!first || (mask & WR_READ_MASK) == 0) {
+			wqe->dma.resid = wqe->dma.length;
+			wqe->dma.cur_sge = 0;
+			wqe->dma.sge_offset = 0;
+		}
+
+		if (first) {
+			first = 0;
+
+			if (mask & WR_WRITE_OR_SEND_MASK) {
+				npsn = (qp->comp.psn - wqe->first_psn) &
+					BTH_PSN_MASK;
+				retry_first_write_send(qp, wqe, npsn);
+			}
+
+			if (mask & WR_READ_MASK) {
+				npsn = (wqe->dma.length - wqe->dma.resid) /
+					qp->mtu;
+				wqe->iova += npsn * qp->mtu;
+			}
+		}
+
+		wqe->state = wqe_state_posted;
+	}
+}
+
+void rnr_nak_timer(struct timer_list *t)
+{
+	struct rxe_qp *qp = from_timer(qp, t, rnr_nak_timer);
+
+	pr_debug("%s: fired for qp#%d\n", __func__, qp_num(qp));
+
+	/* request a send queue retry */
+	qp->req.need_retry = 1;
+	qp->req.wait_for_rnr_timer = 0;
+	rxe_sched_task(&qp->req.task);
+}
+
+static struct rxe_send_wqe *req_next_wqe(struct rxe_qp *qp)
+{
+	struct rxe_send_wqe *wqe;
+	struct rxe_queue *q = qp->sq.queue;
+	unsigned int index = qp->req.wqe_index;
+	unsigned int cons;
+	unsigned int prod;
+
+	wqe = queue_head(q, QUEUE_TYPE_FROM_CLIENT);
+	cons = queue_get_consumer(q, QUEUE_TYPE_FROM_CLIENT);
+	prod = queue_get_producer(q, QUEUE_TYPE_FROM_CLIENT);
+
+	if (unlikely(qp->req.state == QP_STATE_DRAIN)) {
+		/* check to see if we are drained;
+		 * state_lock used by requester and completer
+		 */
+		spin_lock_bh(&qp->state_lock);
+		do {
+			if (qp->req.state != QP_STATE_DRAIN) {
+				/* comp just finished */
+				spin_unlock_bh(&qp->state_lock);
+				break;
+			}
+
+			if (wqe && ((index != cons) ||
+				(wqe->state != wqe_state_posted))) {
+				/* comp not done yet */
+				spin_unlock_bh(&qp->state_lock);
+				break;
+			}
+
+			qp->req.state = QP_STATE_DRAINED;
+			spin_unlock_bh(&qp->state_lock);
+
+			if (qp->ibqp.event_handler) {
+				struct ib_event ev;
+
+				ev.device = qp->ibqp.device;
+				ev.element.qp = &qp->ibqp;
+				ev.event = IB_EVENT_SQ_DRAINED;
+				qp->ibqp.event_handler(&ev,
+					qp->ibqp.qp_context);
+			}
+		} while (0);
+	}
+
+	if (index == prod)
+		return NULL;
+
+	wqe = queue_addr_from_index(q, index);
+
+	if (unlikely((qp->req.state == QP_STATE_DRAIN ||
+		      qp->req.state == QP_STATE_DRAINED) &&
+		     (wqe->state != wqe_state_processing)))
+		return NULL;
+
+	wqe->mask = wr_opcode_mask(wqe->wr.opcode, qp);
+	return wqe;
+}
+
+/**
+ * rxe_wqe_is_fenced - check if next wqe is fenced
+ * @qp: the queue pair
+ * @wqe: the next wqe
+ *
+ * Returns: 1 if wqe needs to wait
+ *	    0 if wqe is ready to go
+ */
+static int rxe_wqe_is_fenced(struct rxe_qp *qp, struct rxe_send_wqe *wqe)
+{
+	/* Local invalidate fence (LIF) see IBA 10.6.5.1
+	 * Requires ALL previous operations on the send queue
+	 * are complete. Make mandatory for the rxe driver.
+	 */
+	if (wqe->wr.opcode == IB_WR_LOCAL_INV)
+		return qp->req.wqe_index != queue_get_consumer(qp->sq.queue,
+						QUEUE_TYPE_FROM_CLIENT);
+
+	/* Fence see IBA 10.8.3.3
+	 * Requires that all previous read and atomic operations
+	 * are complete.
+	 */
+	return (wqe->wr.send_flags & IB_SEND_FENCE) &&
+		atomic_read(&qp->req.rd_atomic) != qp->attr.max_rd_atomic;
+}
+
+static int next_opcode_rc(struct rxe_qp *qp, u32 opcode, int fits)
+{
+	switch (opcode) {
+	case IB_WR_RDMA_WRITE:
+		if (qp->req.opcode == IB_OPCODE_RC_RDMA_WRITE_FIRST ||
+		    qp->req.opcode == IB_OPCODE_RC_RDMA_WRITE_MIDDLE)
+			return fits ?
+				IB_OPCODE_RC_RDMA_WRITE_LAST :
+				IB_OPCODE_RC_RDMA_WRITE_MIDDLE;
+		else
+			return fits ?
+				IB_OPCODE_RC_RDMA_WRITE_ONLY :
+				IB_OPCODE_RC_RDMA_WRITE_FIRST;
+
+	case IB_WR_RDMA_WRITE_WITH_IMM:
+		if (qp->req.opcode == IB_OPCODE_RC_RDMA_WRITE_FIRST ||
+		    qp->req.opcode == IB_OPCODE_RC_RDMA_WRITE_MIDDLE)
+			return fits ?
+				IB_OPCODE_RC_RDMA_WRITE_LAST_WITH_IMMEDIATE :
+				IB_OPCODE_RC_RDMA_WRITE_MIDDLE;
+		else
+			return fits ?
+				IB_OPCODE_RC_RDMA_WRITE_ONLY_WITH_IMMEDIATE :
+				IB_OPCODE_RC_RDMA_WRITE_FIRST;
+
+	case IB_WR_SEND:
+		if (qp->req.opcode == IB_OPCODE_RC_SEND_FIRST ||
+		    qp->req.opcode == IB_OPCODE_RC_SEND_MIDDLE)
+			return fits ?
+				IB_OPCODE_RC_SEND_LAST :
+				IB_OPCODE_RC_SEND_MIDDLE;
+		else
+			return fits ?
+				IB_OPCODE_RC_SEND_ONLY :
+				IB_OPCODE_RC_SEND_FIRST;
+
+	case IB_WR_SEND_WITH_IMM:
+		if (qp->req.opcode == IB_OPCODE_RC_SEND_FIRST ||
+		    qp->req.opcode == IB_OPCODE_RC_SEND_MIDDLE)
+			return fits ?
+				IB_OPCODE_RC_SEND_LAST_WITH_IMMEDIATE :
+				IB_OPCODE_RC_SEND_MIDDLE;
+		else
+			return fits ?
+				IB_OPCODE_RC_SEND_ONLY_WITH_IMMEDIATE :
+				IB_OPCODE_RC_SEND_FIRST;
+
+	case IB_WR_RDMA_READ:
+		return IB_OPCODE_RC_RDMA_READ_REQUEST;
+
+	case IB_WR_ATOMIC_CMP_AND_SWP:
+		return IB_OPCODE_RC_COMPARE_SWAP;
+
+	case IB_WR_ATOMIC_FETCH_AND_ADD:
+		return IB_OPCODE_RC_FETCH_ADD;
+
+	case IB_WR_SEND_WITH_INV:
+		if (qp->req.opcode == IB_OPCODE_RC_SEND_FIRST ||
+		    qp->req.opcode == IB_OPCODE_RC_SEND_MIDDLE)
+			return fits ? IB_OPCODE_RC_SEND_LAST_WITH_INVALIDATE :
+				IB_OPCODE_RC_SEND_MIDDLE;
+		else
+			return fits ? IB_OPCODE_RC_SEND_ONLY_WITH_INVALIDATE :
+				IB_OPCODE_RC_SEND_FIRST;
+	case IB_WR_REG_MR:
+	case IB_WR_LOCAL_INV:
+		return opcode;
+	}
+
+	return -EINVAL;
+}
+
+static int next_opcode_uc(struct rxe_qp *qp, u32 opcode, int fits)
+{
+	switch (opcode) {
+	case IB_WR_RDMA_WRITE:
+		if (qp->req.opcode == IB_OPCODE_UC_RDMA_WRITE_FIRST ||
+		    qp->req.opcode == IB_OPCODE_UC_RDMA_WRITE_MIDDLE)
+			return fits ?
+				IB_OPCODE_UC_RDMA_WRITE_LAST :
+				IB_OPCODE_UC_RDMA_WRITE_MIDDLE;
+		else
+			return fits ?
+				IB_OPCODE_UC_RDMA_WRITE_ONLY :
+				IB_OPCODE_UC_RDMA_WRITE_FIRST;
+
+	case IB_WR_RDMA_WRITE_WITH_IMM:
+		if (qp->req.opcode == IB_OPCODE_UC_RDMA_WRITE_FIRST ||
+		    qp->req.opcode == IB_OPCODE_UC_RDMA_WRITE_MIDDLE)
+			return fits ?
+				IB_OPCODE_UC_RDMA_WRITE_LAST_WITH_IMMEDIATE :
+				IB_OPCODE_UC_RDMA_WRITE_MIDDLE;
+		else
+			return fits ?
+				IB_OPCODE_UC_RDMA_WRITE_ONLY_WITH_IMMEDIATE :
+				IB_OPCODE_UC_RDMA_WRITE_FIRST;
+
+	case IB_WR_SEND:
+		if (qp->req.opcode == IB_OPCODE_UC_SEND_FIRST ||
+		    qp->req.opcode == IB_OPCODE_UC_SEND_MIDDLE)
+			return fits ?
+				IB_OPCODE_UC_SEND_LAST :
+				IB_OPCODE_UC_SEND_MIDDLE;
+		else
+			return fits ?
+				IB_OPCODE_UC_SEND_ONLY :
+				IB_OPCODE_UC_SEND_FIRST;
+
+	case IB_WR_SEND_WITH_IMM:
+		if (qp->req.opcode == IB_OPCODE_UC_SEND_FIRST ||
+		    qp->req.opcode == IB_OPCODE_UC_SEND_MIDDLE)
+			return fits ?
+				IB_OPCODE_UC_SEND_LAST_WITH_IMMEDIATE :
+				IB_OPCODE_UC_SEND_MIDDLE;
+		else
+			return fits ?
+				IB_OPCODE_UC_SEND_ONLY_WITH_IMMEDIATE :
+				IB_OPCODE_UC_SEND_FIRST;
+	}
+
+	return -EINVAL;
+}
+
+static int next_opcode(struct rxe_qp *qp, struct rxe_send_wqe *wqe,
+		       u32 opcode)
+{
+	int fits = (wqe->dma.resid <= qp->mtu);
+
+	switch (qp_type(qp)) {
+	case IB_QPT_RC:
+		return next_opcode_rc(qp, opcode, fits);
+
+	case IB_QPT_UC:
+		return next_opcode_uc(qp, opcode, fits);
+
+	case IB_QPT_UD:
+	case IB_QPT_GSI:
+		switch (opcode) {
+		case IB_WR_SEND:
+			return IB_OPCODE_UD_SEND_ONLY;
+
+		case IB_WR_SEND_WITH_IMM:
+			return IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE;
+		}
+		break;
+
+	default:
+		break;
+	}
+
+	return -EINVAL;
+}
+
+static inline int check_init_depth(struct rxe_qp *qp, struct rxe_send_wqe *wqe)
+{
+	int depth;
+
+	if (wqe->has_rd_atomic)
+		return 0;
+
+	qp->req.need_rd_atomic = 1;
+	depth = atomic_dec_return(&qp->req.rd_atomic);
+
+	if (depth >= 0) {
+		qp->req.need_rd_atomic = 0;
+		wqe->has_rd_atomic = 1;
+		return 0;
+	}
+
+	atomic_inc(&qp->req.rd_atomic);
+	return -EAGAIN;
+}
+
+static inline int get_mtu(struct rxe_qp *qp)
+{
+	struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
+
+	if ((qp_type(qp) == IB_QPT_RC) || (qp_type(qp) == IB_QPT_UC))
+		return qp->mtu;
+
+	return rxe->port.mtu_cap;
+}
+
+static struct sk_buff *init_req_packet(struct rxe_qp *qp,
+				       struct rxe_av *av,
+				       struct rxe_send_wqe *wqe,
+				       int opcode, u32 payload,
+				       struct rxe_pkt_info *pkt)
+{
+	struct rxe_dev		*rxe = to_rdev(qp->ibqp.device);
+	struct sk_buff		*skb;
+	struct rxe_send_wr	*ibwr = &wqe->wr;
+	int			pad = (-payload) & 0x3;
+	int			paylen;
+	int			solicited;
+	u32			qp_num;
+	int			ack_req;
+
+	/* length from start of bth to end of icrc */
+	paylen = rxe_opcode[opcode].length + payload + pad + RXE_ICRC_SIZE;
+	pkt->paylen = paylen;
+
+	/* init skb */
+	skb = rxe_init_packet(rxe, av, paylen, pkt);
+	if (unlikely(!skb))
+		return NULL;
+
+	/* init bth */
+	solicited = (ibwr->send_flags & IB_SEND_SOLICITED) &&
+			(pkt->mask & RXE_END_MASK) &&
+			((pkt->mask & (RXE_SEND_MASK)) ||
+			(pkt->mask & (RXE_WRITE_MASK | RXE_IMMDT_MASK)) ==
+			(RXE_WRITE_MASK | RXE_IMMDT_MASK));
+
+	qp_num = (pkt->mask & RXE_DETH_MASK) ? ibwr->wr.ud.remote_qpn :
+					 qp->attr.dest_qp_num;
+
+	ack_req = ((pkt->mask & RXE_END_MASK) ||
+		(qp->req.noack_pkts++ > RXE_MAX_PKT_PER_ACK));
+	if (ack_req)
+		qp->req.noack_pkts = 0;
+
+	bth_init(pkt, pkt->opcode, solicited, 0, pad, IB_DEFAULT_PKEY_FULL, qp_num,
+		 ack_req, pkt->psn);
+
+	/* init optional headers */
+	if (pkt->mask & RXE_RETH_MASK) {
+		reth_set_rkey(pkt, ibwr->wr.rdma.rkey);
+		reth_set_va(pkt, wqe->iova);
+		reth_set_len(pkt, wqe->dma.resid);
+	}
+
+	if (pkt->mask & RXE_IMMDT_MASK)
+		immdt_set_imm(pkt, ibwr->ex.imm_data);
+
+	if (pkt->mask & RXE_IETH_MASK)
+		ieth_set_rkey(pkt, ibwr->ex.invalidate_rkey);
+
+	if (pkt->mask & RXE_ATMETH_MASK) {
+		atmeth_set_va(pkt, wqe->iova);
+		if (opcode == IB_OPCODE_RC_COMPARE_SWAP) {
+			atmeth_set_swap_add(pkt, ibwr->wr.atomic.swap);
+			atmeth_set_comp(pkt, ibwr->wr.atomic.compare_add);
+		} else {
+			atmeth_set_swap_add(pkt, ibwr->wr.atomic.compare_add);
+		}
+		atmeth_set_rkey(pkt, ibwr->wr.atomic.rkey);
+	}
+
+	if (pkt->mask & RXE_DETH_MASK) {
+		if (qp->ibqp.qp_num == 1)
+			deth_set_qkey(pkt, GSI_QKEY);
+		else
+			deth_set_qkey(pkt, ibwr->wr.ud.remote_qkey);
+		deth_set_sqp(pkt, qp->ibqp.qp_num);
+	}
+
+	return skb;
+}
+
+static int finish_packet(struct rxe_qp *qp, struct rxe_av *av,
+			 struct rxe_send_wqe *wqe, struct rxe_pkt_info *pkt,
+			 struct sk_buff *skb, u32 payload)
+{
+	int err;
+
+	err = rxe_prepare(av, pkt, skb);
+	if (err)
+		return err;
+
+	if (pkt->mask & RXE_WRITE_OR_SEND_MASK) {
+		if (wqe->wr.send_flags & IB_SEND_INLINE) {
+			u8 *tmp = &wqe->dma.inline_data[wqe->dma.sge_offset];
+
+			memcpy(payload_addr(pkt), tmp, payload);
+
+			wqe->dma.resid -= payload;
+			wqe->dma.sge_offset += payload;
+		} else {
+			err = copy_data(qp->pd, 0, &wqe->dma,
+					payload_addr(pkt), payload,
+					RXE_FROM_MR_OBJ);
+			if (err)
+				return err;
+		}
+		if (bth_pad(pkt)) {
+			u8 *pad = payload_addr(pkt) + payload;
+
+			memset(pad, 0, bth_pad(pkt));
+		}
+	}
+
+	return 0;
+}
+
+static void update_wqe_state(struct rxe_qp *qp,
+		struct rxe_send_wqe *wqe,
+		struct rxe_pkt_info *pkt)
+{
+	if (pkt->mask & RXE_END_MASK) {
+		if (qp_type(qp) == IB_QPT_RC)
+			wqe->state = wqe_state_pending;
+	} else {
+		wqe->state = wqe_state_processing;
+	}
+}
+
+static void update_wqe_psn(struct rxe_qp *qp,
+			   struct rxe_send_wqe *wqe,
+			   struct rxe_pkt_info *pkt,
+			   u32 payload)
+{
+	/* number of packets left to send including current one */
+	int num_pkt = (wqe->dma.resid + payload + qp->mtu - 1) / qp->mtu;
+
+	/* handle zero length packet case */
+	if (num_pkt == 0)
+		num_pkt = 1;
+
+	if (pkt->mask & RXE_START_MASK) {
+		wqe->first_psn = qp->req.psn;
+		wqe->last_psn = (qp->req.psn + num_pkt - 1) & BTH_PSN_MASK;
+	}
+
+	if (pkt->mask & RXE_READ_MASK)
+		qp->req.psn = (wqe->first_psn + num_pkt) & BTH_PSN_MASK;
+	else
+		qp->req.psn = (qp->req.psn + 1) & BTH_PSN_MASK;
+}
+
+static void save_state(struct rxe_send_wqe *wqe,
+		       struct rxe_qp *qp,
+		       struct rxe_send_wqe *rollback_wqe,
+		       u32 *rollback_psn)
+{
+	rollback_wqe->state = wqe->state;
+	rollback_wqe->first_psn = wqe->first_psn;
+	rollback_wqe->last_psn = wqe->last_psn;
+	rollback_wqe->dma = wqe->dma;
+	*rollback_psn = qp->req.psn;
+}
+
+static void rollback_state(struct rxe_send_wqe *wqe,
+			   struct rxe_qp *qp,
+			   struct rxe_send_wqe *rollback_wqe,
+			   u32 rollback_psn)
+{
+	wqe->state = rollback_wqe->state;
+	wqe->first_psn = rollback_wqe->first_psn;
+	wqe->last_psn = rollback_wqe->last_psn;
+	wqe->dma = rollback_wqe->dma;
+	qp->req.psn = rollback_psn;
+}
+
+static void update_state(struct rxe_qp *qp, struct rxe_pkt_info *pkt)
+{
+	qp->req.opcode = pkt->opcode;
+
+	if (pkt->mask & RXE_END_MASK)
+		qp->req.wqe_index = queue_next_index(qp->sq.queue,
+						     qp->req.wqe_index);
+
+	qp->need_req_skb = 0;
+
+	if (qp->qp_timeout_jiffies && !timer_pending(&qp->retrans_timer))
+		mod_timer(&qp->retrans_timer,
+			  jiffies + qp->qp_timeout_jiffies);
+}
+
+static int rxe_do_local_ops(struct rxe_qp *qp, struct rxe_send_wqe *wqe)
+{
+	u8 opcode = wqe->wr.opcode;
+	u32 rkey;
+	int ret;
+
+	switch (opcode) {
+	case IB_WR_LOCAL_INV:
+		rkey = wqe->wr.ex.invalidate_rkey;
+		if (rkey_is_mw(rkey))
+			ret = rxe_invalidate_mw(qp, rkey);
+		else
+			ret = rxe_invalidate_mr(qp, rkey);
+
+		if (unlikely(ret)) {
+			wqe->status = IB_WC_LOC_QP_OP_ERR;
+			return ret;
+		}
+		break;
+	case IB_WR_REG_MR:
+		ret = rxe_reg_fast_mr(qp, wqe);
+		if (unlikely(ret)) {
+			wqe->status = IB_WC_LOC_QP_OP_ERR;
+			return ret;
+		}
+		break;
+	case IB_WR_BIND_MW:
+		ret = rxe_bind_mw(qp, wqe);
+		if (unlikely(ret)) {
+			wqe->status = IB_WC_MW_BIND_ERR;
+			return ret;
+		}
+		break;
+	default:
+		pr_err("Unexpected send wqe opcode %d\n", opcode);
+		wqe->status = IB_WC_LOC_QP_OP_ERR;
+		return -EINVAL;
+	}
+
+	wqe->state = wqe_state_done;
+	wqe->status = IB_WC_SUCCESS;
+	qp->req.wqe_index = queue_next_index(qp->sq.queue, qp->req.wqe_index);
+
+	/* There is no ack coming for local work requests
+	 * which can lead to a deadlock. So go ahead and complete
+	 * it now.
+	 */
+	rxe_sched_task(&qp->comp.task);
+
+	return 0;
+}
+
+int rxe_requester(void *arg)
+{
+	struct rxe_qp *qp = (struct rxe_qp *)arg;
+	struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
+	struct rxe_pkt_info pkt;
+	struct sk_buff *skb;
+	struct rxe_send_wqe *wqe;
+	enum rxe_hdr_mask mask;
+	u32 payload;
+	int mtu;
+	int opcode;
+	int err;
+	int ret;
+	struct rxe_send_wqe rollback_wqe;
+	u32 rollback_psn;
+	struct rxe_queue *q = qp->sq.queue;
+	struct rxe_ah *ah;
+	struct rxe_av *av;
+
+	if (!rxe_get(qp))
+		return -EAGAIN;
+
+	if (unlikely(!qp->valid))
+		goto exit;
+
+	if (unlikely(qp->req.state == QP_STATE_ERROR)) {
+		wqe = req_next_wqe(qp);
+		if (wqe)
+			/*
+			 * Generate an error completion for error qp state
+			 */
+			goto err;
+		else
+			goto exit;
+	}
+
+	if (unlikely(qp->req.state == QP_STATE_RESET)) {
+		qp->req.wqe_index = queue_get_consumer(q,
+						QUEUE_TYPE_FROM_CLIENT);
+		qp->req.opcode = -1;
+		qp->req.need_rd_atomic = 0;
+		qp->req.wait_psn = 0;
+		qp->req.need_retry = 0;
+		qp->req.wait_for_rnr_timer = 0;
+		goto exit;
+	}
+
+	/* we come here if the retransmit timer has fired
+	 * or if the rnr timer has fired. If the retransmit
+	 * timer fires while we are processing an RNR NAK wait
+	 * until the rnr timer has fired before starting the
+	 * retry flow
+	 */
+	if (unlikely(qp->req.need_retry && !qp->req.wait_for_rnr_timer)) {
+		req_retry(qp);
+		qp->req.need_retry = 0;
+	}
+
+	wqe = req_next_wqe(qp);
+	if (unlikely(!wqe))
+		goto exit;
+
+	if (rxe_wqe_is_fenced(qp, wqe)) {
+		qp->req.wait_fence = 1;
+		goto exit;
+	}
+
+	if (wqe->mask & WR_LOCAL_OP_MASK) {
+		err = rxe_do_local_ops(qp, wqe);
+		if (unlikely(err))
+			goto err;
+		else
+			goto done;
+	}
+
+	if (unlikely(qp_type(qp) == IB_QPT_RC &&
+		psn_compare(qp->req.psn, (qp->comp.psn +
+				RXE_MAX_UNACKED_PSNS)) > 0)) {
+		qp->req.wait_psn = 1;
+		goto exit;
+	}
+
+	/* Limit the number of inflight SKBs per QP */
+	if (unlikely(atomic_read(&qp->skb_out) >
+		     RXE_INFLIGHT_SKBS_PER_QP_HIGH)) {
+		qp->need_req_skb = 1;
+		goto exit;
+	}
+
+	opcode = next_opcode(qp, wqe, wqe->wr.opcode);
+	if (unlikely(opcode < 0)) {
+		wqe->status = IB_WC_LOC_QP_OP_ERR;
+		goto err;
+	}
+
+	mask = rxe_opcode[opcode].mask;
+	if (unlikely(mask & RXE_READ_OR_ATOMIC_MASK)) {
+		if (check_init_depth(qp, wqe))
+			goto exit;
+	}
+
+	mtu = get_mtu(qp);
+	payload = (mask & RXE_WRITE_OR_SEND_MASK) ? wqe->dma.resid : 0;
+	if (payload > mtu) {
+		if (qp_type(qp) == IB_QPT_UD) {
+			/* C10-93.1.1: If the total sum of all the buffer lengths specified for a
+			 * UD message exceeds the MTU of the port as returned by QueryHCA, the CI
+			 * shall not emit any packets for this message. Further, the CI shall not
+			 * generate an error due to this condition.
+			 */
+
+			/* fake a successful UD send */
+			wqe->first_psn = qp->req.psn;
+			wqe->last_psn = qp->req.psn;
+			qp->req.psn = (qp->req.psn + 1) & BTH_PSN_MASK;
+			qp->req.opcode = IB_OPCODE_UD_SEND_ONLY;
+			qp->req.wqe_index = queue_next_index(qp->sq.queue,
+						       qp->req.wqe_index);
+			wqe->state = wqe_state_done;
+			wqe->status = IB_WC_SUCCESS;
+			rxe_run_task(&qp->comp.task);
+			goto done;
+		}
+		payload = mtu;
+	}
+
+	pkt.rxe = rxe;
+	pkt.opcode = opcode;
+	pkt.qp = qp;
+	pkt.psn = qp->req.psn;
+	pkt.mask = rxe_opcode[opcode].mask;
+	pkt.wqe = wqe;
+
+	/* save wqe state before we build and send packet */
+	save_state(wqe, qp, &rollback_wqe, &rollback_psn);
+
+	av = rxe_get_av(&pkt, &ah);
+	if (unlikely(!av)) {
+		pr_err("qp#%d Failed no address vector\n", qp_num(qp));
+		wqe->status = IB_WC_LOC_QP_OP_ERR;
+		goto err;
+	}
+
+	skb = init_req_packet(qp, av, wqe, opcode, payload, &pkt);
+	if (unlikely(!skb)) {
+		pr_err("qp#%d Failed allocating skb\n", qp_num(qp));
+		wqe->status = IB_WC_LOC_QP_OP_ERR;
+		if (ah)
+			rxe_put(ah);
+		goto err;
+	}
+
+	err = finish_packet(qp, av, wqe, &pkt, skb, payload);
+	if (unlikely(err)) {
+		pr_debug("qp#%d Error during finish packet\n", qp_num(qp));
+		if (err == -EFAULT)
+			wqe->status = IB_WC_LOC_PROT_ERR;
+		else
+			wqe->status = IB_WC_LOC_QP_OP_ERR;
+		kfree_skb(skb);
+		if (ah)
+			rxe_put(ah);
+		goto err;
+	}
+
+	if (ah)
+		rxe_put(ah);
+
+	/* update wqe state as though we had sent it */
+	update_wqe_state(qp, wqe, &pkt);
+	update_wqe_psn(qp, wqe, &pkt, payload);
+
+	err = rxe_xmit_packet(qp, &pkt, skb);
+	if (err) {
+		if (err != -EAGAIN) {
+			wqe->status = IB_WC_LOC_QP_OP_ERR;
+			goto err;
+		}
+
+		/* the packet was dropped so reset wqe to the state
+		 * before we sent it so we can try to resend
+		 */
+		rollback_state(wqe, qp, &rollback_wqe, rollback_psn);
+
+		/* force a delay until the dropped packet is freed and
+		 * the send queue is drained below the low water mark
+		 */
+		qp->need_req_skb = 1;
+
+		rxe_sched_task(&qp->req.task);
+		goto exit;
+	}
+
+	update_state(qp, &pkt);
+
+	/* A non-zero return value will cause rxe_do_task to
+	 * exit its loop and end the tasklet. A zero return
+	 * will continue looping and return to rxe_requester
+	 */
+done:
+	ret = 0;
+	goto out;
+err:
+	/* update wqe_index for each wqe completion */
+	qp->req.wqe_index = queue_next_index(qp->sq.queue, qp->req.wqe_index);
+	wqe->state = wqe_state_error;
+	qp->req.state = QP_STATE_ERROR;
+	rxe_run_task(&qp->comp.task);
+exit:
+	ret = -EAGAIN;
+out:
+	rxe_put(qp);
+
+	return ret;
+}