drivers/infiniband/hw/hfi1/ruc.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
 /*
  * Copyright(c) 2015 - 2018 Intel Corporation.
  */

 #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
  * @bth1: bth1 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
  * @bth1: bth1 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
  * @qp: a pointer to QP
  * @ps: a pointer to a structure with commonly lookup values for
  *      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);
 }
	// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
	/*
	* Copyright(c) 2015 - 2018 Intel Corporation.
	*/

	#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
	* @bth1: bth1 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
	* @bth1: bth1 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
	* @qp: a pointer to QP
	* @ps: a pointer to a structure with commonly lookup values for
	* 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);
	}