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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/infiniband/hw/hfi1/ruc.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r--drivers/infiniband/hw/hfi1/ruc.c575
1 files changed, 575 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..b0151b729
--- /dev/null
+++ b/drivers/infiniband/hw/hfi1/ruc.c
@@ -0,0 +1,575 @@
+// 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);
+}