Adding upstream version 5.10.209.upstream/5.10.209

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

1 files changed, 616 insertions, 0 deletions

diff --git a/drivers/infiniband/hw/hfi1/ruc.c b/drivers/infiniband/hw/hfi1/ruc.c
new file mode 100644
index 000000000..23ac6057b
--- /dev/null
+++ b/drivers/infiniband/hw/hfi1/ruc.c
@@ -0,0 +1,616 @@
+/*
+ * Copyright(c) 2015 - 2018 Intel Corporation.
+ *
+ * This file is provided under a dual BSD/GPLv2 license.  When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * GPL LICENSE SUMMARY
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * BSD LICENSE
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *  - Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  - Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *  - Neither the name of Intel Corporation nor the names of its
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <linux/spinlock.h>
+
+#include "hfi.h"
+#include "mad.h"
+#include "qp.h"
+#include "verbs_txreq.h"
+#include "trace.h"
+
+static int gid_ok(union ib_gid *gid, __be64 gid_prefix, __be64 id)
+{
+	return (gid->global.interface_id == id &&
+		(gid->global.subnet_prefix == gid_prefix ||
+		 gid->global.subnet_prefix == IB_DEFAULT_GID_PREFIX));
+}
+
+/*
+ *
+ * This should be called with the QP r_lock held.
+ *
+ * The s_lock will be acquired around the hfi1_migrate_qp() call.
+ */
+int hfi1_ruc_check_hdr(struct hfi1_ibport *ibp, struct hfi1_packet *packet)
+{
+	__be64 guid;
+	unsigned long flags;
+	struct rvt_qp *qp = packet->qp;
+	u8 sc5 = ibp->sl_to_sc[rdma_ah_get_sl(&qp->remote_ah_attr)];
+	u32 dlid = packet->dlid;
+	u32 slid = packet->slid;
+	u32 sl = packet->sl;
+	bool migrated = packet->migrated;
+	u16 pkey = packet->pkey;
+
+	if (qp->s_mig_state == IB_MIG_ARMED && migrated) {
+		if (!packet->grh) {
+			if ((rdma_ah_get_ah_flags(&qp->alt_ah_attr) &
+			     IB_AH_GRH) &&
+			    (packet->etype != RHF_RCV_TYPE_BYPASS))
+				return 1;
+		} else {
+			const struct ib_global_route *grh;
+
+			if (!(rdma_ah_get_ah_flags(&qp->alt_ah_attr) &
+			      IB_AH_GRH))
+				return 1;
+			grh = rdma_ah_read_grh(&qp->alt_ah_attr);
+			guid = get_sguid(ibp, grh->sgid_index);
+			if (!gid_ok(&packet->grh->dgid, ibp->rvp.gid_prefix,
+				    guid))
+				return 1;
+			if (!gid_ok(
+				&packet->grh->sgid,
+				grh->dgid.global.subnet_prefix,
+				grh->dgid.global.interface_id))
+				return 1;
+		}
+		if (unlikely(rcv_pkey_check(ppd_from_ibp(ibp), pkey,
+					    sc5, slid))) {
+			hfi1_bad_pkey(ibp, pkey, sl, 0, qp->ibqp.qp_num,
+				      slid, dlid);
+			return 1;
+		}
+		/* Validate the SLID. See Ch. 9.6.1.5 and 17.2.8 */
+		if (slid != rdma_ah_get_dlid(&qp->alt_ah_attr) ||
+		    ppd_from_ibp(ibp)->port !=
+			rdma_ah_get_port_num(&qp->alt_ah_attr))
+			return 1;
+		spin_lock_irqsave(&qp->s_lock, flags);
+		hfi1_migrate_qp(qp);
+		spin_unlock_irqrestore(&qp->s_lock, flags);
+	} else {
+		if (!packet->grh) {
+			if ((rdma_ah_get_ah_flags(&qp->remote_ah_attr) &
+			     IB_AH_GRH) &&
+			    (packet->etype != RHF_RCV_TYPE_BYPASS))
+				return 1;
+		} else {
+			const struct ib_global_route *grh;
+
+			if (!(rdma_ah_get_ah_flags(&qp->remote_ah_attr) &
+						   IB_AH_GRH))
+				return 1;
+			grh = rdma_ah_read_grh(&qp->remote_ah_attr);
+			guid = get_sguid(ibp, grh->sgid_index);
+			if (!gid_ok(&packet->grh->dgid, ibp->rvp.gid_prefix,
+				    guid))
+				return 1;
+			if (!gid_ok(
+			     &packet->grh->sgid,
+			     grh->dgid.global.subnet_prefix,
+			     grh->dgid.global.interface_id))
+				return 1;
+		}
+		if (unlikely(rcv_pkey_check(ppd_from_ibp(ibp), pkey,
+					    sc5, slid))) {
+			hfi1_bad_pkey(ibp, pkey, sl, 0, qp->ibqp.qp_num,
+				      slid, dlid);
+			return 1;
+		}
+		/* Validate the SLID. See Ch. 9.6.1.5 */
+		if ((slid != rdma_ah_get_dlid(&qp->remote_ah_attr)) ||
+		    ppd_from_ibp(ibp)->port != qp->port_num)
+			return 1;
+		if (qp->s_mig_state == IB_MIG_REARM && !migrated)
+			qp->s_mig_state = IB_MIG_ARMED;
+	}
+
+	return 0;
+}
+
+/**
+ * hfi1_make_grh - construct a GRH header
+ * @ibp: a pointer to the IB port
+ * @hdr: a pointer to the GRH header being constructed
+ * @grh: the global route address to send to
+ * @hwords: size of header after grh being sent in dwords
+ * @nwords: the number of 32 bit words of data being sent
+ *
+ * Return the size of the header in 32 bit words.
+ */
+u32 hfi1_make_grh(struct hfi1_ibport *ibp, struct ib_grh *hdr,
+		  const struct ib_global_route *grh, u32 hwords, u32 nwords)
+{
+	hdr->version_tclass_flow =
+		cpu_to_be32((IB_GRH_VERSION << IB_GRH_VERSION_SHIFT) |
+			    (grh->traffic_class << IB_GRH_TCLASS_SHIFT) |
+			    (grh->flow_label << IB_GRH_FLOW_SHIFT));
+	hdr->paylen = cpu_to_be16((hwords + nwords) << 2);
+	/* next_hdr is defined by C8-7 in ch. 8.4.1 */
+	hdr->next_hdr = IB_GRH_NEXT_HDR;
+	hdr->hop_limit = grh->hop_limit;
+	/* The SGID is 32-bit aligned. */
+	hdr->sgid.global.subnet_prefix = ibp->rvp.gid_prefix;
+	hdr->sgid.global.interface_id =
+		grh->sgid_index < HFI1_GUIDS_PER_PORT ?
+		get_sguid(ibp, grh->sgid_index) :
+		get_sguid(ibp, HFI1_PORT_GUID_INDEX);
+	hdr->dgid = grh->dgid;
+
+	/* GRH header size in 32-bit words. */
+	return sizeof(struct ib_grh) / sizeof(u32);
+}
+
+#define BTH2_OFFSET (offsetof(struct hfi1_sdma_header, \
+			      hdr.ibh.u.oth.bth[2]) / 4)
+
+/**
+ * build_ahg - create ahg in s_ahg
+ * @qp: a pointer to QP
+ * @npsn: the next PSN for the request/response
+ *
+ * This routine handles the AHG by allocating an ahg entry and causing the
+ * copy of the first middle.
+ *
+ * Subsequent middles use the copied entry, editing the
+ * PSN with 1 or 2 edits.
+ */
+static inline void build_ahg(struct rvt_qp *qp, u32 npsn)
+{
+	struct hfi1_qp_priv *priv = qp->priv;
+
+	if (unlikely(qp->s_flags & HFI1_S_AHG_CLEAR))
+		clear_ahg(qp);
+	if (!(qp->s_flags & HFI1_S_AHG_VALID)) {
+		/* first middle that needs copy  */
+		if (qp->s_ahgidx < 0)
+			qp->s_ahgidx = sdma_ahg_alloc(priv->s_sde);
+		if (qp->s_ahgidx >= 0) {
+			qp->s_ahgpsn = npsn;
+			priv->s_ahg->tx_flags |= SDMA_TXREQ_F_AHG_COPY;
+			/* save to protect a change in another thread */
+			priv->s_ahg->ahgidx = qp->s_ahgidx;
+			qp->s_flags |= HFI1_S_AHG_VALID;
+		}
+	} else {
+		/* subsequent middle after valid */
+		if (qp->s_ahgidx >= 0) {
+			priv->s_ahg->tx_flags |= SDMA_TXREQ_F_USE_AHG;
+			priv->s_ahg->ahgidx = qp->s_ahgidx;
+			priv->s_ahg->ahgcount++;
+			priv->s_ahg->ahgdesc[0] =
+				sdma_build_ahg_descriptor(
+					(__force u16)cpu_to_be16((u16)npsn),
+					BTH2_OFFSET,
+					16,
+					16);
+			if ((npsn & 0xffff0000) !=
+					(qp->s_ahgpsn & 0xffff0000)) {
+				priv->s_ahg->ahgcount++;
+				priv->s_ahg->ahgdesc[1] =
+					sdma_build_ahg_descriptor(
+						(__force u16)cpu_to_be16(
+							(u16)(npsn >> 16)),
+						BTH2_OFFSET,
+						0,
+						16);
+			}
+		}
+	}
+}
+
+static inline void hfi1_make_ruc_bth(struct rvt_qp *qp,
+				     struct ib_other_headers *ohdr,
+				     u32 bth0, u32 bth1, u32 bth2)
+{
+	ohdr->bth[0] = cpu_to_be32(bth0);
+	ohdr->bth[1] = cpu_to_be32(bth1);
+	ohdr->bth[2] = cpu_to_be32(bth2);
+}
+
+/**
+ * hfi1_make_ruc_header_16B - build a 16B header
+ * @qp: the queue pair
+ * @ohdr: a pointer to the destination header memory
+ * @bth0: bth0 passed in from the RC/UC builder
+ * @bth2: bth2 passed in from the RC/UC builder
+ * @middle: non zero implies indicates ahg "could" be used
+ * @ps: the current packet state
+ *
+ * This routine may disarm ahg under these situations:
+ * - packet needs a GRH
+ * - BECN needed
+ * - migration state not IB_MIG_MIGRATED
+ */
+static inline void hfi1_make_ruc_header_16B(struct rvt_qp *qp,
+					    struct ib_other_headers *ohdr,
+					    u32 bth0, u32 bth1, u32 bth2,
+					    int middle,
+					    struct hfi1_pkt_state *ps)
+{
+	struct hfi1_qp_priv *priv = qp->priv;
+	struct hfi1_ibport *ibp = ps->ibp;
+	struct hfi1_pportdata *ppd = ppd_from_ibp(ibp);
+	u32 slid;
+	u16 pkey = hfi1_get_pkey(ibp, qp->s_pkey_index);
+	u8 l4 = OPA_16B_L4_IB_LOCAL;
+	u8 extra_bytes = hfi1_get_16b_padding(
+				(ps->s_txreq->hdr_dwords << 2),
+				ps->s_txreq->s_cur_size);
+	u32 nwords = SIZE_OF_CRC + ((ps->s_txreq->s_cur_size +
+				 extra_bytes + SIZE_OF_LT) >> 2);
+	bool becn = false;
+
+	if (unlikely(rdma_ah_get_ah_flags(&qp->remote_ah_attr) & IB_AH_GRH) &&
+	    hfi1_check_mcast(rdma_ah_get_dlid(&qp->remote_ah_attr))) {
+		struct ib_grh *grh;
+		struct ib_global_route *grd =
+			rdma_ah_retrieve_grh(&qp->remote_ah_attr);
+		/*
+		 * Ensure OPA GIDs are transformed to IB gids
+		 * before creating the GRH.
+		 */
+		if (grd->sgid_index == OPA_GID_INDEX)
+			grd->sgid_index = 0;
+		grh = &ps->s_txreq->phdr.hdr.opah.u.l.grh;
+		l4 = OPA_16B_L4_IB_GLOBAL;
+		ps->s_txreq->hdr_dwords +=
+			hfi1_make_grh(ibp, grh, grd,
+				      ps->s_txreq->hdr_dwords - LRH_16B_DWORDS,
+				      nwords);
+		middle = 0;
+	}
+
+	if (qp->s_mig_state == IB_MIG_MIGRATED)
+		bth1 |= OPA_BTH_MIG_REQ;
+	else
+		middle = 0;
+
+	if (qp->s_flags & RVT_S_ECN) {
+		qp->s_flags &= ~RVT_S_ECN;
+		/* we recently received a FECN, so return a BECN */
+		becn = true;
+		middle = 0;
+	}
+	if (middle)
+		build_ahg(qp, bth2);
+	else
+		qp->s_flags &= ~HFI1_S_AHG_VALID;
+
+	bth0 |= pkey;
+	bth0 |= extra_bytes << 20;
+	hfi1_make_ruc_bth(qp, ohdr, bth0, bth1, bth2);
+
+	if (!ppd->lid)
+		slid = be32_to_cpu(OPA_LID_PERMISSIVE);
+	else
+		slid = ppd->lid |
+			(rdma_ah_get_path_bits(&qp->remote_ah_attr) &
+			((1 << ppd->lmc) - 1));
+
+	hfi1_make_16b_hdr(&ps->s_txreq->phdr.hdr.opah,
+			  slid,
+			  opa_get_lid(rdma_ah_get_dlid(&qp->remote_ah_attr),
+				      16B),
+			  (ps->s_txreq->hdr_dwords + nwords) >> 1,
+			  pkey, becn, 0, l4, priv->s_sc);
+}
+
+/**
+ * hfi1_make_ruc_header_9B - build a 9B header
+ * @qp: the queue pair
+ * @ohdr: a pointer to the destination header memory
+ * @bth0: bth0 passed in from the RC/UC builder
+ * @bth2: bth2 passed in from the RC/UC builder
+ * @middle: non zero implies indicates ahg "could" be used
+ * @ps: the current packet state
+ *
+ * This routine may disarm ahg under these situations:
+ * - packet needs a GRH
+ * - BECN needed
+ * - migration state not IB_MIG_MIGRATED
+ */
+static inline void hfi1_make_ruc_header_9B(struct rvt_qp *qp,
+					   struct ib_other_headers *ohdr,
+					   u32 bth0, u32 bth1, u32 bth2,
+					   int middle,
+					   struct hfi1_pkt_state *ps)
+{
+	struct hfi1_qp_priv *priv = qp->priv;
+	struct hfi1_ibport *ibp = ps->ibp;
+	u16 pkey = hfi1_get_pkey(ibp, qp->s_pkey_index);
+	u16 lrh0 = HFI1_LRH_BTH;
+	u8 extra_bytes = -ps->s_txreq->s_cur_size & 3;
+	u32 nwords = SIZE_OF_CRC + ((ps->s_txreq->s_cur_size +
+					 extra_bytes) >> 2);
+
+	if (unlikely(rdma_ah_get_ah_flags(&qp->remote_ah_attr) & IB_AH_GRH)) {
+		struct ib_grh *grh = &ps->s_txreq->phdr.hdr.ibh.u.l.grh;
+
+		lrh0 = HFI1_LRH_GRH;
+		ps->s_txreq->hdr_dwords +=
+			hfi1_make_grh(ibp, grh,
+				      rdma_ah_read_grh(&qp->remote_ah_attr),
+				      ps->s_txreq->hdr_dwords - LRH_9B_DWORDS,
+				      nwords);
+		middle = 0;
+	}
+	lrh0 |= (priv->s_sc & 0xf) << 12 |
+		(rdma_ah_get_sl(&qp->remote_ah_attr) & 0xf) << 4;
+
+	if (qp->s_mig_state == IB_MIG_MIGRATED)
+		bth0 |= IB_BTH_MIG_REQ;
+	else
+		middle = 0;
+
+	if (qp->s_flags & RVT_S_ECN) {
+		qp->s_flags &= ~RVT_S_ECN;
+		/* we recently received a FECN, so return a BECN */
+		bth1 |= (IB_BECN_MASK << IB_BECN_SHIFT);
+		middle = 0;
+	}
+	if (middle)
+		build_ahg(qp, bth2);
+	else
+		qp->s_flags &= ~HFI1_S_AHG_VALID;
+
+	bth0 |= pkey;
+	bth0 |= extra_bytes << 20;
+	hfi1_make_ruc_bth(qp, ohdr, bth0, bth1, bth2);
+	hfi1_make_ib_hdr(&ps->s_txreq->phdr.hdr.ibh,
+			 lrh0,
+			 ps->s_txreq->hdr_dwords + nwords,
+			 opa_get_lid(rdma_ah_get_dlid(&qp->remote_ah_attr), 9B),
+			 ppd_from_ibp(ibp)->lid |
+				rdma_ah_get_path_bits(&qp->remote_ah_attr));
+}
+
+typedef void (*hfi1_make_ruc_hdr)(struct rvt_qp *qp,
+				  struct ib_other_headers *ohdr,
+				  u32 bth0, u32 bth1, u32 bth2, int middle,
+				  struct hfi1_pkt_state *ps);
+
+/* We support only two types - 9B and 16B for now */
+static const hfi1_make_ruc_hdr hfi1_ruc_header_tbl[2] = {
+	[HFI1_PKT_TYPE_9B] = &hfi1_make_ruc_header_9B,
+	[HFI1_PKT_TYPE_16B] = &hfi1_make_ruc_header_16B
+};
+
+void hfi1_make_ruc_header(struct rvt_qp *qp, struct ib_other_headers *ohdr,
+			  u32 bth0, u32 bth1, u32 bth2, int middle,
+			  struct hfi1_pkt_state *ps)
+{
+	struct hfi1_qp_priv *priv = qp->priv;
+
+	/*
+	 * reset s_ahg/AHG fields
+	 *
+	 * This insures that the ahgentry/ahgcount
+	 * are at a non-AHG default to protect
+	 * build_verbs_tx_desc() from using
+	 * an include ahgidx.
+	 *
+	 * build_ahg() will modify as appropriate
+	 * to use the AHG feature.
+	 */
+	priv->s_ahg->tx_flags = 0;
+	priv->s_ahg->ahgcount = 0;
+	priv->s_ahg->ahgidx = 0;
+
+	/* Make the appropriate header */
+	hfi1_ruc_header_tbl[priv->hdr_type](qp, ohdr, bth0, bth1, bth2, middle,
+					    ps);
+}
+
+/* when sending, force a reschedule every one of these periods */
+#define SEND_RESCHED_TIMEOUT (5 * HZ)  /* 5s in jiffies */
+
+/**
+ * hfi1_schedule_send_yield - test for a yield required for QP
+ * send engine
+ * @timeout: Final time for timeout slice for jiffies
+ * @qp: a pointer to QP
+ * @ps: a pointer to a structure with commonly lookup values for
+ *      the the send engine progress
+ * @tid - true if it is the tid leg
+ *
+ * This routine checks if the time slice for the QP has expired
+ * for RC QPs, if so an additional work entry is queued. At this
+ * point, other QPs have an opportunity to be scheduled. It
+ * returns true if a yield is required, otherwise, false
+ * is returned.
+ */
+bool hfi1_schedule_send_yield(struct rvt_qp *qp, struct hfi1_pkt_state *ps,
+			      bool tid)
+{
+	ps->pkts_sent = true;
+
+	if (unlikely(time_after(jiffies, ps->timeout))) {
+		if (!ps->in_thread ||
+		    workqueue_congested(ps->cpu, ps->ppd->hfi1_wq)) {
+			spin_lock_irqsave(&qp->s_lock, ps->flags);
+			if (!tid) {
+				qp->s_flags &= ~RVT_S_BUSY;
+				hfi1_schedule_send(qp);
+			} else {
+				struct hfi1_qp_priv *priv = qp->priv;
+
+				if (priv->s_flags &
+				    HFI1_S_TID_BUSY_SET) {
+					qp->s_flags &= ~RVT_S_BUSY;
+					priv->s_flags &=
+						~(HFI1_S_TID_BUSY_SET |
+						  RVT_S_BUSY);
+				} else {
+					priv->s_flags &= ~RVT_S_BUSY;
+				}
+				hfi1_schedule_tid_send(qp);
+			}
+
+			spin_unlock_irqrestore(&qp->s_lock, ps->flags);
+			this_cpu_inc(*ps->ppd->dd->send_schedule);
+			trace_hfi1_rc_expired_time_slice(qp, true);
+			return true;
+		}
+
+		cond_resched();
+		this_cpu_inc(*ps->ppd->dd->send_schedule);
+		ps->timeout = jiffies + ps->timeout_int;
+	}
+
+	trace_hfi1_rc_expired_time_slice(qp, false);
+	return false;
+}
+
+void hfi1_do_send_from_rvt(struct rvt_qp *qp)
+{
+	hfi1_do_send(qp, false);
+}
+
+void _hfi1_do_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_send(qp, true);
+}
+
+/**
+ * hfi1_do_send - perform a send on a QP
+ * @qp: a pointer to the QP
+ * @in_thread: true if in a workqueue thread
+ *
+ * Process entries in the send work queue until credit or queue is
+ * exhausted.  Only allow one CPU to send a packet per QP.
+ * Otherwise, two threads could send packets out of order.
+ */
+void hfi1_do_send(struct rvt_qp *qp, bool in_thread)
+{
+	struct hfi1_pkt_state ps;
+	struct hfi1_qp_priv *priv = qp->priv;
+	int (*make_req)(struct rvt_qp *qp, struct hfi1_pkt_state *ps);
+
+	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.in_thread = in_thread;
+	ps.wait = iowait_get_ib_work(&priv->s_iowait);
+
+	trace_hfi1_rc_do_send(qp, in_thread);
+
+	switch (qp->ibqp.qp_type) {
+	case IB_QPT_RC:
+		if (!loopback && ((rdma_ah_get_dlid(&qp->remote_ah_attr) &
+				   ~((1 << ps.ppd->lmc) - 1)) ==
+				  ps.ppd->lid)) {
+			rvt_ruc_loopback(qp);
+			return;
+		}
+		make_req = hfi1_make_rc_req;
+		ps.timeout_int = qp->timeout_jiffies;
+		break;
+	case IB_QPT_UC:
+		if (!loopback && ((rdma_ah_get_dlid(&qp->remote_ah_attr) &
+				   ~((1 << ps.ppd->lmc) - 1)) ==
+				  ps.ppd->lid)) {
+			rvt_ruc_loopback(qp);
+			return;
+		}
+		make_req = hfi1_make_uc_req;
+		ps.timeout_int = SEND_RESCHED_TIMEOUT;
+		break;
+	default:
+		make_req = hfi1_make_ud_req;
+		ps.timeout_int = SEND_RESCHED_TIMEOUT;
+	}
+
+	spin_lock_irqsave(&qp->s_lock, ps.flags);
+
+	/* Return if we are already busy processing a work request. */
+	if (!hfi1_send_ok(qp)) {
+		if (qp->s_flags & HFI1_S_ANY_WAIT_IO)
+			iowait_set_flag(&priv->s_iowait, IOWAIT_PENDING_IB);
+		spin_unlock_irqrestore(&qp->s_lock, ps.flags);
+		return;
+	}
+
+	qp->s_flags |= RVT_S_BUSY;
+
+	ps.timeout_int = ps.timeout_int / 8;
+	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;
+			spin_unlock_irqrestore(&qp->s_lock, ps.flags);
+			/*
+			 * If the packet cannot be sent now, return and
+			 * the send engine will be woken up later.
+			 */
+			if (hfi1_verbs_send(qp, &ps))
+				return;
+
+			/* allow other tasks to run */
+			if (hfi1_schedule_send_yield(qp, &ps, false))
+				return;
+
+			spin_lock_irqsave(&qp->s_lock, ps.flags);
+		}
+	} while (make_req(qp, &ps));
+	iowait_starve_clear(ps.pkts_sent, &priv->s_iowait);
+	spin_unlock_irqrestore(&qp->s_lock, ps.flags);
+}