1 // SPDX-License-Identifier: GPL-2.0 or BSD-3-Clause
2 /*
3 * Copyright(c) 2015 - 2018 Intel Corporation.
4 */
5
6 #include <linux/spinlock.h>
7
8 #include "hfi.h"
9 #include "mad.h"
10 #include "qp.h"
11 #include "verbs_txreq.h"
12 #include "trace.h"
13
gid_ok(union ib_gid * gid,__be64 gid_prefix,__be64 id)14 static int gid_ok(union ib_gid *gid, __be64 gid_prefix, __be64 id)
15 {
16 return (gid->global.interface_id == id &&
17 (gid->global.subnet_prefix == gid_prefix ||
18 gid->global.subnet_prefix == IB_DEFAULT_GID_PREFIX));
19 }
20
21 /*
22 *
23 * This should be called with the QP r_lock held.
24 *
25 * The s_lock will be acquired around the hfi1_migrate_qp() call.
26 */
hfi1_ruc_check_hdr(struct hfi1_ibport * ibp,struct hfi1_packet * packet)27 int hfi1_ruc_check_hdr(struct hfi1_ibport *ibp, struct hfi1_packet *packet)
28 {
29 __be64 guid;
30 unsigned long flags;
31 struct rvt_qp *qp = packet->qp;
32 u8 sc5 = ibp->sl_to_sc[rdma_ah_get_sl(&qp->remote_ah_attr)];
33 u32 dlid = packet->dlid;
34 u32 slid = packet->slid;
35 u32 sl = packet->sl;
36 bool migrated = packet->migrated;
37 u16 pkey = packet->pkey;
38
39 if (qp->s_mig_state == IB_MIG_ARMED && migrated) {
40 if (!packet->grh) {
41 if ((rdma_ah_get_ah_flags(&qp->alt_ah_attr) &
42 IB_AH_GRH) &&
43 (packet->etype != RHF_RCV_TYPE_BYPASS))
44 return 1;
45 } else {
46 const struct ib_global_route *grh;
47
48 if (!(rdma_ah_get_ah_flags(&qp->alt_ah_attr) &
49 IB_AH_GRH))
50 return 1;
51 grh = rdma_ah_read_grh(&qp->alt_ah_attr);
52 guid = get_sguid(ibp, grh->sgid_index);
53 if (!gid_ok(&packet->grh->dgid, ibp->rvp.gid_prefix,
54 guid))
55 return 1;
56 if (!gid_ok(
57 &packet->grh->sgid,
58 grh->dgid.global.subnet_prefix,
59 grh->dgid.global.interface_id))
60 return 1;
61 }
62 if (unlikely(rcv_pkey_check(ppd_from_ibp(ibp), pkey,
63 sc5, slid))) {
64 hfi1_bad_pkey(ibp, pkey, sl, 0, qp->ibqp.qp_num,
65 slid, dlid);
66 return 1;
67 }
68 /* Validate the SLID. See Ch. 9.6.1.5 and 17.2.8 */
69 if (slid != rdma_ah_get_dlid(&qp->alt_ah_attr) ||
70 ppd_from_ibp(ibp)->port !=
71 rdma_ah_get_port_num(&qp->alt_ah_attr))
72 return 1;
73 spin_lock_irqsave(&qp->s_lock, flags);
74 hfi1_migrate_qp(qp);
75 spin_unlock_irqrestore(&qp->s_lock, flags);
76 } else {
77 if (!packet->grh) {
78 if ((rdma_ah_get_ah_flags(&qp->remote_ah_attr) &
79 IB_AH_GRH) &&
80 (packet->etype != RHF_RCV_TYPE_BYPASS))
81 return 1;
82 } else {
83 const struct ib_global_route *grh;
84
85 if (!(rdma_ah_get_ah_flags(&qp->remote_ah_attr) &
86 IB_AH_GRH))
87 return 1;
88 grh = rdma_ah_read_grh(&qp->remote_ah_attr);
89 guid = get_sguid(ibp, grh->sgid_index);
90 if (!gid_ok(&packet->grh->dgid, ibp->rvp.gid_prefix,
91 guid))
92 return 1;
93 if (!gid_ok(
94 &packet->grh->sgid,
95 grh->dgid.global.subnet_prefix,
96 grh->dgid.global.interface_id))
97 return 1;
98 }
99 if (unlikely(rcv_pkey_check(ppd_from_ibp(ibp), pkey,
100 sc5, slid))) {
101 hfi1_bad_pkey(ibp, pkey, sl, 0, qp->ibqp.qp_num,
102 slid, dlid);
103 return 1;
104 }
105 /* Validate the SLID. See Ch. 9.6.1.5 */
106 if ((slid != rdma_ah_get_dlid(&qp->remote_ah_attr)) ||
107 ppd_from_ibp(ibp)->port != qp->port_num)
108 return 1;
109 if (qp->s_mig_state == IB_MIG_REARM && !migrated)
110 qp->s_mig_state = IB_MIG_ARMED;
111 }
112
113 return 0;
114 }
115
116 /**
117 * hfi1_make_grh - construct a GRH header
118 * @ibp: a pointer to the IB port
119 * @hdr: a pointer to the GRH header being constructed
120 * @grh: the global route address to send to
121 * @hwords: size of header after grh being sent in dwords
122 * @nwords: the number of 32 bit words of data being sent
123 *
124 * Return the size of the header in 32 bit words.
125 */
hfi1_make_grh(struct hfi1_ibport * ibp,struct ib_grh * hdr,const struct ib_global_route * grh,u32 hwords,u32 nwords)126 u32 hfi1_make_grh(struct hfi1_ibport *ibp, struct ib_grh *hdr,
127 const struct ib_global_route *grh, u32 hwords, u32 nwords)
128 {
129 hdr->version_tclass_flow =
130 cpu_to_be32((IB_GRH_VERSION << IB_GRH_VERSION_SHIFT) |
131 (grh->traffic_class << IB_GRH_TCLASS_SHIFT) |
132 (grh->flow_label << IB_GRH_FLOW_SHIFT));
133 hdr->paylen = cpu_to_be16((hwords + nwords) << 2);
134 /* next_hdr is defined by C8-7 in ch. 8.4.1 */
135 hdr->next_hdr = IB_GRH_NEXT_HDR;
136 hdr->hop_limit = grh->hop_limit;
137 /* The SGID is 32-bit aligned. */
138 hdr->sgid.global.subnet_prefix = ibp->rvp.gid_prefix;
139 hdr->sgid.global.interface_id =
140 grh->sgid_index < HFI1_GUIDS_PER_PORT ?
141 get_sguid(ibp, grh->sgid_index) :
142 get_sguid(ibp, HFI1_PORT_GUID_INDEX);
143 hdr->dgid = grh->dgid;
144
145 /* GRH header size in 32-bit words. */
146 return sizeof(struct ib_grh) / sizeof(u32);
147 }
148
149 #define BTH2_OFFSET (offsetof(struct hfi1_sdma_header, \
150 hdr.ibh.u.oth.bth[2]) / 4)
151
152 /**
153 * build_ahg - create ahg in s_ahg
154 * @qp: a pointer to QP
155 * @npsn: the next PSN for the request/response
156 *
157 * This routine handles the AHG by allocating an ahg entry and causing the
158 * copy of the first middle.
159 *
160 * Subsequent middles use the copied entry, editing the
161 * PSN with 1 or 2 edits.
162 */
build_ahg(struct rvt_qp * qp,u32 npsn)163 static inline void build_ahg(struct rvt_qp *qp, u32 npsn)
164 {
165 struct hfi1_qp_priv *priv = qp->priv;
166
167 if (unlikely(qp->s_flags & HFI1_S_AHG_CLEAR))
168 clear_ahg(qp);
169 if (!(qp->s_flags & HFI1_S_AHG_VALID)) {
170 /* first middle that needs copy */
171 if (qp->s_ahgidx < 0)
172 qp->s_ahgidx = sdma_ahg_alloc(priv->s_sde);
173 if (qp->s_ahgidx >= 0) {
174 qp->s_ahgpsn = npsn;
175 priv->s_ahg->tx_flags |= SDMA_TXREQ_F_AHG_COPY;
176 /* save to protect a change in another thread */
177 priv->s_ahg->ahgidx = qp->s_ahgidx;
178 qp->s_flags |= HFI1_S_AHG_VALID;
179 }
180 } else {
181 /* subsequent middle after valid */
182 if (qp->s_ahgidx >= 0) {
183 priv->s_ahg->tx_flags |= SDMA_TXREQ_F_USE_AHG;
184 priv->s_ahg->ahgidx = qp->s_ahgidx;
185 priv->s_ahg->ahgcount++;
186 priv->s_ahg->ahgdesc[0] =
187 sdma_build_ahg_descriptor(
188 (__force u16)cpu_to_be16((u16)npsn),
189 BTH2_OFFSET,
190 16,
191 16);
192 if ((npsn & 0xffff0000) !=
193 (qp->s_ahgpsn & 0xffff0000)) {
194 priv->s_ahg->ahgcount++;
195 priv->s_ahg->ahgdesc[1] =
196 sdma_build_ahg_descriptor(
197 (__force u16)cpu_to_be16(
198 (u16)(npsn >> 16)),
199 BTH2_OFFSET,
200 0,
201 16);
202 }
203 }
204 }
205 }
206
hfi1_make_ruc_bth(struct rvt_qp * qp,struct ib_other_headers * ohdr,u32 bth0,u32 bth1,u32 bth2)207 static inline void hfi1_make_ruc_bth(struct rvt_qp *qp,
208 struct ib_other_headers *ohdr,
209 u32 bth0, u32 bth1, u32 bth2)
210 {
211 ohdr->bth[0] = cpu_to_be32(bth0);
212 ohdr->bth[1] = cpu_to_be32(bth1);
213 ohdr->bth[2] = cpu_to_be32(bth2);
214 }
215
216 /**
217 * hfi1_make_ruc_header_16B - build a 16B header
218 * @qp: the queue pair
219 * @ohdr: a pointer to the destination header memory
220 * @bth0: bth0 passed in from the RC/UC builder
221 * @bth1: bth1 passed in from the RC/UC builder
222 * @bth2: bth2 passed in from the RC/UC builder
223 * @middle: non zero implies indicates ahg "could" be used
224 * @ps: the current packet state
225 *
226 * This routine may disarm ahg under these situations:
227 * - packet needs a GRH
228 * - BECN needed
229 * - migration state not IB_MIG_MIGRATED
230 */
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)231 static inline void hfi1_make_ruc_header_16B(struct rvt_qp *qp,
232 struct ib_other_headers *ohdr,
233 u32 bth0, u32 bth1, u32 bth2,
234 int middle,
235 struct hfi1_pkt_state *ps)
236 {
237 struct hfi1_qp_priv *priv = qp->priv;
238 struct hfi1_ibport *ibp = ps->ibp;
239 struct hfi1_pportdata *ppd = ppd_from_ibp(ibp);
240 u32 slid;
241 u16 pkey = hfi1_get_pkey(ibp, qp->s_pkey_index);
242 u8 l4 = OPA_16B_L4_IB_LOCAL;
243 u8 extra_bytes = hfi1_get_16b_padding(
244 (ps->s_txreq->hdr_dwords << 2),
245 ps->s_txreq->s_cur_size);
246 u32 nwords = SIZE_OF_CRC + ((ps->s_txreq->s_cur_size +
247 extra_bytes + SIZE_OF_LT) >> 2);
248 bool becn = false;
249
250 if (unlikely(rdma_ah_get_ah_flags(&qp->remote_ah_attr) & IB_AH_GRH) &&
251 hfi1_check_mcast(rdma_ah_get_dlid(&qp->remote_ah_attr))) {
252 struct ib_grh *grh;
253 struct ib_global_route *grd =
254 rdma_ah_retrieve_grh(&qp->remote_ah_attr);
255 /*
256 * Ensure OPA GIDs are transformed to IB gids
257 * before creating the GRH.
258 */
259 if (grd->sgid_index == OPA_GID_INDEX)
260 grd->sgid_index = 0;
261 grh = &ps->s_txreq->phdr.hdr.opah.u.l.grh;
262 l4 = OPA_16B_L4_IB_GLOBAL;
263 ps->s_txreq->hdr_dwords +=
264 hfi1_make_grh(ibp, grh, grd,
265 ps->s_txreq->hdr_dwords - LRH_16B_DWORDS,
266 nwords);
267 middle = 0;
268 }
269
270 if (qp->s_mig_state == IB_MIG_MIGRATED)
271 bth1 |= OPA_BTH_MIG_REQ;
272 else
273 middle = 0;
274
275 if (qp->s_flags & RVT_S_ECN) {
276 qp->s_flags &= ~RVT_S_ECN;
277 /* we recently received a FECN, so return a BECN */
278 becn = true;
279 middle = 0;
280 }
281 if (middle)
282 build_ahg(qp, bth2);
283 else
284 qp->s_flags &= ~HFI1_S_AHG_VALID;
285
286 bth0 |= pkey;
287 bth0 |= extra_bytes << 20;
288 hfi1_make_ruc_bth(qp, ohdr, bth0, bth1, bth2);
289
290 if (!ppd->lid)
291 slid = be32_to_cpu(OPA_LID_PERMISSIVE);
292 else
293 slid = ppd->lid |
294 (rdma_ah_get_path_bits(&qp->remote_ah_attr) &
295 ((1 << ppd->lmc) - 1));
296
297 hfi1_make_16b_hdr(&ps->s_txreq->phdr.hdr.opah,
298 slid,
299 opa_get_lid(rdma_ah_get_dlid(&qp->remote_ah_attr),
300 16B),
301 (ps->s_txreq->hdr_dwords + nwords) >> 1,
302 pkey, becn, 0, l4, priv->s_sc);
303 }
304
305 /**
306 * hfi1_make_ruc_header_9B - build a 9B header
307 * @qp: the queue pair
308 * @ohdr: a pointer to the destination header memory
309 * @bth0: bth0 passed in from the RC/UC builder
310 * @bth1: bth1 passed in from the RC/UC builder
311 * @bth2: bth2 passed in from the RC/UC builder
312 * @middle: non zero implies indicates ahg "could" be used
313 * @ps: the current packet state
314 *
315 * This routine may disarm ahg under these situations:
316 * - packet needs a GRH
317 * - BECN needed
318 * - migration state not IB_MIG_MIGRATED
319 */
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)320 static inline void hfi1_make_ruc_header_9B(struct rvt_qp *qp,
321 struct ib_other_headers *ohdr,
322 u32 bth0, u32 bth1, u32 bth2,
323 int middle,
324 struct hfi1_pkt_state *ps)
325 {
326 struct hfi1_qp_priv *priv = qp->priv;
327 struct hfi1_ibport *ibp = ps->ibp;
328 u16 pkey = hfi1_get_pkey(ibp, qp->s_pkey_index);
329 u16 lrh0 = HFI1_LRH_BTH;
330 u8 extra_bytes = -ps->s_txreq->s_cur_size & 3;
331 u32 nwords = SIZE_OF_CRC + ((ps->s_txreq->s_cur_size +
332 extra_bytes) >> 2);
333
334 if (unlikely(rdma_ah_get_ah_flags(&qp->remote_ah_attr) & IB_AH_GRH)) {
335 struct ib_grh *grh = &ps->s_txreq->phdr.hdr.ibh.u.l.grh;
336
337 lrh0 = HFI1_LRH_GRH;
338 ps->s_txreq->hdr_dwords +=
339 hfi1_make_grh(ibp, grh,
340 rdma_ah_read_grh(&qp->remote_ah_attr),
341 ps->s_txreq->hdr_dwords - LRH_9B_DWORDS,
342 nwords);
343 middle = 0;
344 }
345 lrh0 |= (priv->s_sc & 0xf) << 12 |
346 (rdma_ah_get_sl(&qp->remote_ah_attr) & 0xf) << 4;
347
348 if (qp->s_mig_state == IB_MIG_MIGRATED)
349 bth0 |= IB_BTH_MIG_REQ;
350 else
351 middle = 0;
352
353 if (qp->s_flags & RVT_S_ECN) {
354 qp->s_flags &= ~RVT_S_ECN;
355 /* we recently received a FECN, so return a BECN */
356 bth1 |= (IB_BECN_MASK << IB_BECN_SHIFT);
357 middle = 0;
358 }
359 if (middle)
360 build_ahg(qp, bth2);
361 else
362 qp->s_flags &= ~HFI1_S_AHG_VALID;
363
364 bth0 |= pkey;
365 bth0 |= extra_bytes << 20;
366 hfi1_make_ruc_bth(qp, ohdr, bth0, bth1, bth2);
367 hfi1_make_ib_hdr(&ps->s_txreq->phdr.hdr.ibh,
368 lrh0,
369 ps->s_txreq->hdr_dwords + nwords,
370 opa_get_lid(rdma_ah_get_dlid(&qp->remote_ah_attr), 9B),
371 ppd_from_ibp(ibp)->lid |
372 rdma_ah_get_path_bits(&qp->remote_ah_attr));
373 }
374
375 typedef void (*hfi1_make_ruc_hdr)(struct rvt_qp *qp,
376 struct ib_other_headers *ohdr,
377 u32 bth0, u32 bth1, u32 bth2, int middle,
378 struct hfi1_pkt_state *ps);
379
380 /* We support only two types - 9B and 16B for now */
381 static const hfi1_make_ruc_hdr hfi1_ruc_header_tbl[2] = {
382 [HFI1_PKT_TYPE_9B] = &hfi1_make_ruc_header_9B,
383 [HFI1_PKT_TYPE_16B] = &hfi1_make_ruc_header_16B
384 };
385
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)386 void hfi1_make_ruc_header(struct rvt_qp *qp, struct ib_other_headers *ohdr,
387 u32 bth0, u32 bth1, u32 bth2, int middle,
388 struct hfi1_pkt_state *ps)
389 {
390 struct hfi1_qp_priv *priv = qp->priv;
391
392 /*
393 * reset s_ahg/AHG fields
394 *
395 * This insures that the ahgentry/ahgcount
396 * are at a non-AHG default to protect
397 * build_verbs_tx_desc() from using
398 * an include ahgidx.
399 *
400 * build_ahg() will modify as appropriate
401 * to use the AHG feature.
402 */
403 priv->s_ahg->tx_flags = 0;
404 priv->s_ahg->ahgcount = 0;
405 priv->s_ahg->ahgidx = 0;
406
407 /* Make the appropriate header */
408 hfi1_ruc_header_tbl[priv->hdr_type](qp, ohdr, bth0, bth1, bth2, middle,
409 ps);
410 }
411
412 /* when sending, force a reschedule every one of these periods */
413 #define SEND_RESCHED_TIMEOUT (5 * HZ) /* 5s in jiffies */
414
415 /**
416 * hfi1_schedule_send_yield - test for a yield required for QP
417 * send engine
418 * @qp: a pointer to QP
419 * @ps: a pointer to a structure with commonly lookup values for
420 * the send engine progress
421 * @tid: true if it is the tid leg
422 *
423 * This routine checks if the time slice for the QP has expired
424 * for RC QPs, if so an additional work entry is queued. At this
425 * point, other QPs have an opportunity to be scheduled. It
426 * returns true if a yield is required, otherwise, false
427 * is returned.
428 */
hfi1_schedule_send_yield(struct rvt_qp * qp,struct hfi1_pkt_state * ps,bool tid)429 bool hfi1_schedule_send_yield(struct rvt_qp *qp, struct hfi1_pkt_state *ps,
430 bool tid)
431 {
432 ps->pkts_sent = true;
433
434 if (unlikely(time_after(jiffies, ps->timeout))) {
435 if (!ps->in_thread ||
436 workqueue_congested(ps->cpu, ps->ppd->hfi1_wq)) {
437 spin_lock_irqsave(&qp->s_lock, ps->flags);
438 if (!tid) {
439 qp->s_flags &= ~RVT_S_BUSY;
440 hfi1_schedule_send(qp);
441 } else {
442 struct hfi1_qp_priv *priv = qp->priv;
443
444 if (priv->s_flags &
445 HFI1_S_TID_BUSY_SET) {
446 qp->s_flags &= ~RVT_S_BUSY;
447 priv->s_flags &=
448 ~(HFI1_S_TID_BUSY_SET |
449 RVT_S_BUSY);
450 } else {
451 priv->s_flags &= ~RVT_S_BUSY;
452 }
453 hfi1_schedule_tid_send(qp);
454 }
455
456 spin_unlock_irqrestore(&qp->s_lock, ps->flags);
457 this_cpu_inc(*ps->ppd->dd->send_schedule);
458 trace_hfi1_rc_expired_time_slice(qp, true);
459 return true;
460 }
461
462 cond_resched();
463 this_cpu_inc(*ps->ppd->dd->send_schedule);
464 ps->timeout = jiffies + ps->timeout_int;
465 }
466
467 trace_hfi1_rc_expired_time_slice(qp, false);
468 return false;
469 }
470
hfi1_do_send_from_rvt(struct rvt_qp * qp)471 void hfi1_do_send_from_rvt(struct rvt_qp *qp)
472 {
473 hfi1_do_send(qp, false);
474 }
475
_hfi1_do_send(struct work_struct * work)476 void _hfi1_do_send(struct work_struct *work)
477 {
478 struct iowait_work *w = container_of(work, struct iowait_work, iowork);
479 struct rvt_qp *qp = iowait_to_qp(w->iow);
480
481 hfi1_do_send(qp, true);
482 }
483
484 /**
485 * hfi1_do_send - perform a send on a QP
486 * @qp: a pointer to the QP
487 * @in_thread: true if in a workqueue thread
488 *
489 * Process entries in the send work queue until credit or queue is
490 * exhausted. Only allow one CPU to send a packet per QP.
491 * Otherwise, two threads could send packets out of order.
492 */
hfi1_do_send(struct rvt_qp * qp,bool in_thread)493 void hfi1_do_send(struct rvt_qp *qp, bool in_thread)
494 {
495 struct hfi1_pkt_state ps;
496 struct hfi1_qp_priv *priv = qp->priv;
497 int (*make_req)(struct rvt_qp *qp, struct hfi1_pkt_state *ps);
498
499 ps.dev = to_idev(qp->ibqp.device);
500 ps.ibp = to_iport(qp->ibqp.device, qp->port_num);
501 ps.ppd = ppd_from_ibp(ps.ibp);
502 ps.in_thread = in_thread;
503 ps.wait = iowait_get_ib_work(&priv->s_iowait);
504
505 trace_hfi1_rc_do_send(qp, in_thread);
506
507 switch (qp->ibqp.qp_type) {
508 case IB_QPT_RC:
509 if (!loopback && ((rdma_ah_get_dlid(&qp->remote_ah_attr) &
510 ~((1 << ps.ppd->lmc) - 1)) ==
511 ps.ppd->lid)) {
512 rvt_ruc_loopback(qp);
513 return;
514 }
515 make_req = hfi1_make_rc_req;
516 ps.timeout_int = qp->timeout_jiffies;
517 break;
518 case IB_QPT_UC:
519 if (!loopback && ((rdma_ah_get_dlid(&qp->remote_ah_attr) &
520 ~((1 << ps.ppd->lmc) - 1)) ==
521 ps.ppd->lid)) {
522 rvt_ruc_loopback(qp);
523 return;
524 }
525 make_req = hfi1_make_uc_req;
526 ps.timeout_int = SEND_RESCHED_TIMEOUT;
527 break;
528 default:
529 make_req = hfi1_make_ud_req;
530 ps.timeout_int = SEND_RESCHED_TIMEOUT;
531 }
532
533 spin_lock_irqsave(&qp->s_lock, ps.flags);
534
535 /* Return if we are already busy processing a work request. */
536 if (!hfi1_send_ok(qp)) {
537 if (qp->s_flags & HFI1_S_ANY_WAIT_IO)
538 iowait_set_flag(&priv->s_iowait, IOWAIT_PENDING_IB);
539 spin_unlock_irqrestore(&qp->s_lock, ps.flags);
540 return;
541 }
542
543 qp->s_flags |= RVT_S_BUSY;
544
545 ps.timeout_int = ps.timeout_int / 8;
546 ps.timeout = jiffies + ps.timeout_int;
547 ps.cpu = priv->s_sde ? priv->s_sde->cpu :
548 cpumask_first(cpumask_of_node(ps.ppd->dd->node));
549 ps.pkts_sent = false;
550
551 /* insure a pre-built packet is handled */
552 ps.s_txreq = get_waiting_verbs_txreq(ps.wait);
553 do {
554 /* Check for a constructed packet to be sent. */
555 if (ps.s_txreq) {
556 if (priv->s_flags & HFI1_S_TID_BUSY_SET)
557 qp->s_flags |= RVT_S_BUSY;
558 spin_unlock_irqrestore(&qp->s_lock, ps.flags);
559 /*
560 * If the packet cannot be sent now, return and
561 * the send engine will be woken up later.
562 */
563 if (hfi1_verbs_send(qp, &ps))
564 return;
565
566 /* allow other tasks to run */
567 if (hfi1_schedule_send_yield(qp, &ps, false))
568 return;
569
570 spin_lock_irqsave(&qp->s_lock, ps.flags);
571 }
572 } while (make_req(qp, &ps));
573 iowait_starve_clear(ps.pkts_sent, &priv->s_iowait);
574 spin_unlock_irqrestore(&qp->s_lock, ps.flags);
575 }
576