xref: /openbmc/linux/drivers/infiniband/hw/hfi1/ruc.c (revision 7ce05074)
1 /*
2  * Copyright(c) 2015 - 2018 Intel Corporation.
3  *
4  * This file is provided under a dual BSD/GPLv2 license.  When using or
5  * redistributing this file, you may do so under either license.
6  *
7  * GPL LICENSE SUMMARY
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of version 2 of the GNU General Public License as
11  * published by the Free Software Foundation.
12  *
13  * This program is distributed in the hope that it will be useful, but
14  * WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16  * General Public License for more details.
17  *
18  * BSD LICENSE
19  *
20  * Redistribution and use in source and binary forms, with or without
21  * modification, are permitted provided that the following conditions
22  * are met:
23  *
24  *  - Redistributions of source code must retain the above copyright
25  *    notice, this list of conditions and the following disclaimer.
26  *  - Redistributions in binary form must reproduce the above copyright
27  *    notice, this list of conditions and the following disclaimer in
28  *    the documentation and/or other materials provided with the
29  *    distribution.
30  *  - Neither the name of Intel Corporation nor the names of its
31  *    contributors may be used to endorse or promote products derived
32  *    from this software without specific prior written permission.
33  *
34  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
35  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
36  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
37  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
38  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
39  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
40  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
41  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
42  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
43  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
44  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
45  *
46  */
47 
48 #include <linux/spinlock.h>
49 
50 #include "hfi.h"
51 #include "mad.h"
52 #include "qp.h"
53 #include "verbs_txreq.h"
54 #include "trace.h"
55 
56 static int gid_ok(union ib_gid *gid, __be64 gid_prefix, __be64 id)
57 {
58 	return (gid->global.interface_id == id &&
59 		(gid->global.subnet_prefix == gid_prefix ||
60 		 gid->global.subnet_prefix == IB_DEFAULT_GID_PREFIX));
61 }
62 
63 /*
64  *
65  * This should be called with the QP r_lock held.
66  *
67  * The s_lock will be acquired around the hfi1_migrate_qp() call.
68  */
69 int hfi1_ruc_check_hdr(struct hfi1_ibport *ibp, struct hfi1_packet *packet)
70 {
71 	__be64 guid;
72 	unsigned long flags;
73 	struct rvt_qp *qp = packet->qp;
74 	u8 sc5 = ibp->sl_to_sc[rdma_ah_get_sl(&qp->remote_ah_attr)];
75 	u32 dlid = packet->dlid;
76 	u32 slid = packet->slid;
77 	u32 sl = packet->sl;
78 	bool migrated = packet->migrated;
79 	u16 pkey = packet->pkey;
80 
81 	if (qp->s_mig_state == IB_MIG_ARMED && migrated) {
82 		if (!packet->grh) {
83 			if ((rdma_ah_get_ah_flags(&qp->alt_ah_attr) &
84 			     IB_AH_GRH) &&
85 			    (packet->etype != RHF_RCV_TYPE_BYPASS))
86 				return 1;
87 		} else {
88 			const struct ib_global_route *grh;
89 
90 			if (!(rdma_ah_get_ah_flags(&qp->alt_ah_attr) &
91 			      IB_AH_GRH))
92 				return 1;
93 			grh = rdma_ah_read_grh(&qp->alt_ah_attr);
94 			guid = get_sguid(ibp, grh->sgid_index);
95 			if (!gid_ok(&packet->grh->dgid, ibp->rvp.gid_prefix,
96 				    guid))
97 				return 1;
98 			if (!gid_ok(
99 				&packet->grh->sgid,
100 				grh->dgid.global.subnet_prefix,
101 				grh->dgid.global.interface_id))
102 				return 1;
103 		}
104 		if (unlikely(rcv_pkey_check(ppd_from_ibp(ibp), pkey,
105 					    sc5, slid))) {
106 			hfi1_bad_pkey(ibp, pkey, sl, 0, qp->ibqp.qp_num,
107 				      slid, dlid);
108 			return 1;
109 		}
110 		/* Validate the SLID. See Ch. 9.6.1.5 and 17.2.8 */
111 		if (slid != rdma_ah_get_dlid(&qp->alt_ah_attr) ||
112 		    ppd_from_ibp(ibp)->port !=
113 			rdma_ah_get_port_num(&qp->alt_ah_attr))
114 			return 1;
115 		spin_lock_irqsave(&qp->s_lock, flags);
116 		hfi1_migrate_qp(qp);
117 		spin_unlock_irqrestore(&qp->s_lock, flags);
118 	} else {
119 		if (!packet->grh) {
120 			if ((rdma_ah_get_ah_flags(&qp->remote_ah_attr) &
121 			     IB_AH_GRH) &&
122 			    (packet->etype != RHF_RCV_TYPE_BYPASS))
123 				return 1;
124 		} else {
125 			const struct ib_global_route *grh;
126 
127 			if (!(rdma_ah_get_ah_flags(&qp->remote_ah_attr) &
128 						   IB_AH_GRH))
129 				return 1;
130 			grh = rdma_ah_read_grh(&qp->remote_ah_attr);
131 			guid = get_sguid(ibp, grh->sgid_index);
132 			if (!gid_ok(&packet->grh->dgid, ibp->rvp.gid_prefix,
133 				    guid))
134 				return 1;
135 			if (!gid_ok(
136 			     &packet->grh->sgid,
137 			     grh->dgid.global.subnet_prefix,
138 			     grh->dgid.global.interface_id))
139 				return 1;
140 		}
141 		if (unlikely(rcv_pkey_check(ppd_from_ibp(ibp), pkey,
142 					    sc5, slid))) {
143 			hfi1_bad_pkey(ibp, pkey, sl, 0, qp->ibqp.qp_num,
144 				      slid, dlid);
145 			return 1;
146 		}
147 		/* Validate the SLID. See Ch. 9.6.1.5 */
148 		if ((slid != rdma_ah_get_dlid(&qp->remote_ah_attr)) ||
149 		    ppd_from_ibp(ibp)->port != qp->port_num)
150 			return 1;
151 		if (qp->s_mig_state == IB_MIG_REARM && !migrated)
152 			qp->s_mig_state = IB_MIG_ARMED;
153 	}
154 
155 	return 0;
156 }
157 
158 /**
159  * hfi1_make_grh - construct a GRH header
160  * @ibp: a pointer to the IB port
161  * @hdr: a pointer to the GRH header being constructed
162  * @grh: the global route address to send to
163  * @hwords: size of header after grh being sent in dwords
164  * @nwords: the number of 32 bit words of data being sent
165  *
166  * Return the size of the header in 32 bit words.
167  */
168 u32 hfi1_make_grh(struct hfi1_ibport *ibp, struct ib_grh *hdr,
169 		  const struct ib_global_route *grh, u32 hwords, u32 nwords)
170 {
171 	hdr->version_tclass_flow =
172 		cpu_to_be32((IB_GRH_VERSION << IB_GRH_VERSION_SHIFT) |
173 			    (grh->traffic_class << IB_GRH_TCLASS_SHIFT) |
174 			    (grh->flow_label << IB_GRH_FLOW_SHIFT));
175 	hdr->paylen = cpu_to_be16((hwords + nwords) << 2);
176 	/* next_hdr is defined by C8-7 in ch. 8.4.1 */
177 	hdr->next_hdr = IB_GRH_NEXT_HDR;
178 	hdr->hop_limit = grh->hop_limit;
179 	/* The SGID is 32-bit aligned. */
180 	hdr->sgid.global.subnet_prefix = ibp->rvp.gid_prefix;
181 	hdr->sgid.global.interface_id =
182 		grh->sgid_index < HFI1_GUIDS_PER_PORT ?
183 		get_sguid(ibp, grh->sgid_index) :
184 		get_sguid(ibp, HFI1_PORT_GUID_INDEX);
185 	hdr->dgid = grh->dgid;
186 
187 	/* GRH header size in 32-bit words. */
188 	return sizeof(struct ib_grh) / sizeof(u32);
189 }
190 
191 #define BTH2_OFFSET (offsetof(struct hfi1_sdma_header, \
192 			      hdr.ibh.u.oth.bth[2]) / 4)
193 
194 /**
195  * build_ahg - create ahg in s_ahg
196  * @qp: a pointer to QP
197  * @npsn: the next PSN for the request/response
198  *
199  * This routine handles the AHG by allocating an ahg entry and causing the
200  * copy of the first middle.
201  *
202  * Subsequent middles use the copied entry, editing the
203  * PSN with 1 or 2 edits.
204  */
205 static inline void build_ahg(struct rvt_qp *qp, u32 npsn)
206 {
207 	struct hfi1_qp_priv *priv = qp->priv;
208 
209 	if (unlikely(qp->s_flags & HFI1_S_AHG_CLEAR))
210 		clear_ahg(qp);
211 	if (!(qp->s_flags & HFI1_S_AHG_VALID)) {
212 		/* first middle that needs copy  */
213 		if (qp->s_ahgidx < 0)
214 			qp->s_ahgidx = sdma_ahg_alloc(priv->s_sde);
215 		if (qp->s_ahgidx >= 0) {
216 			qp->s_ahgpsn = npsn;
217 			priv->s_ahg->tx_flags |= SDMA_TXREQ_F_AHG_COPY;
218 			/* save to protect a change in another thread */
219 			priv->s_ahg->ahgidx = qp->s_ahgidx;
220 			qp->s_flags |= HFI1_S_AHG_VALID;
221 		}
222 	} else {
223 		/* subsequent middle after valid */
224 		if (qp->s_ahgidx >= 0) {
225 			priv->s_ahg->tx_flags |= SDMA_TXREQ_F_USE_AHG;
226 			priv->s_ahg->ahgidx = qp->s_ahgidx;
227 			priv->s_ahg->ahgcount++;
228 			priv->s_ahg->ahgdesc[0] =
229 				sdma_build_ahg_descriptor(
230 					(__force u16)cpu_to_be16((u16)npsn),
231 					BTH2_OFFSET,
232 					16,
233 					16);
234 			if ((npsn & 0xffff0000) !=
235 					(qp->s_ahgpsn & 0xffff0000)) {
236 				priv->s_ahg->ahgcount++;
237 				priv->s_ahg->ahgdesc[1] =
238 					sdma_build_ahg_descriptor(
239 						(__force u16)cpu_to_be16(
240 							(u16)(npsn >> 16)),
241 						BTH2_OFFSET,
242 						0,
243 						16);
244 			}
245 		}
246 	}
247 }
248 
249 static inline void hfi1_make_ruc_bth(struct rvt_qp *qp,
250 				     struct ib_other_headers *ohdr,
251 				     u32 bth0, u32 bth1, u32 bth2)
252 {
253 	ohdr->bth[0] = cpu_to_be32(bth0);
254 	ohdr->bth[1] = cpu_to_be32(bth1);
255 	ohdr->bth[2] = cpu_to_be32(bth2);
256 }
257 
258 /**
259  * hfi1_make_ruc_header_16B - build a 16B header
260  * @qp: the queue pair
261  * @ohdr: a pointer to the destination header memory
262  * @bth0: bth0 passed in from the RC/UC builder
263  * @bth1: bth1 passed in from the RC/UC builder
264  * @bth2: bth2 passed in from the RC/UC builder
265  * @middle: non zero implies indicates ahg "could" be used
266  * @ps: the current packet state
267  *
268  * This routine may disarm ahg under these situations:
269  * - packet needs a GRH
270  * - BECN needed
271  * - migration state not IB_MIG_MIGRATED
272  */
273 static inline void hfi1_make_ruc_header_16B(struct rvt_qp *qp,
274 					    struct ib_other_headers *ohdr,
275 					    u32 bth0, u32 bth1, u32 bth2,
276 					    int middle,
277 					    struct hfi1_pkt_state *ps)
278 {
279 	struct hfi1_qp_priv *priv = qp->priv;
280 	struct hfi1_ibport *ibp = ps->ibp;
281 	struct hfi1_pportdata *ppd = ppd_from_ibp(ibp);
282 	u32 slid;
283 	u16 pkey = hfi1_get_pkey(ibp, qp->s_pkey_index);
284 	u8 l4 = OPA_16B_L4_IB_LOCAL;
285 	u8 extra_bytes = hfi1_get_16b_padding(
286 				(ps->s_txreq->hdr_dwords << 2),
287 				ps->s_txreq->s_cur_size);
288 	u32 nwords = SIZE_OF_CRC + ((ps->s_txreq->s_cur_size +
289 				 extra_bytes + SIZE_OF_LT) >> 2);
290 	bool becn = false;
291 
292 	if (unlikely(rdma_ah_get_ah_flags(&qp->remote_ah_attr) & IB_AH_GRH) &&
293 	    hfi1_check_mcast(rdma_ah_get_dlid(&qp->remote_ah_attr))) {
294 		struct ib_grh *grh;
295 		struct ib_global_route *grd =
296 			rdma_ah_retrieve_grh(&qp->remote_ah_attr);
297 		/*
298 		 * Ensure OPA GIDs are transformed to IB gids
299 		 * before creating the GRH.
300 		 */
301 		if (grd->sgid_index == OPA_GID_INDEX)
302 			grd->sgid_index = 0;
303 		grh = &ps->s_txreq->phdr.hdr.opah.u.l.grh;
304 		l4 = OPA_16B_L4_IB_GLOBAL;
305 		ps->s_txreq->hdr_dwords +=
306 			hfi1_make_grh(ibp, grh, grd,
307 				      ps->s_txreq->hdr_dwords - LRH_16B_DWORDS,
308 				      nwords);
309 		middle = 0;
310 	}
311 
312 	if (qp->s_mig_state == IB_MIG_MIGRATED)
313 		bth1 |= OPA_BTH_MIG_REQ;
314 	else
315 		middle = 0;
316 
317 	if (qp->s_flags & RVT_S_ECN) {
318 		qp->s_flags &= ~RVT_S_ECN;
319 		/* we recently received a FECN, so return a BECN */
320 		becn = true;
321 		middle = 0;
322 	}
323 	if (middle)
324 		build_ahg(qp, bth2);
325 	else
326 		qp->s_flags &= ~HFI1_S_AHG_VALID;
327 
328 	bth0 |= pkey;
329 	bth0 |= extra_bytes << 20;
330 	hfi1_make_ruc_bth(qp, ohdr, bth0, bth1, bth2);
331 
332 	if (!ppd->lid)
333 		slid = be32_to_cpu(OPA_LID_PERMISSIVE);
334 	else
335 		slid = ppd->lid |
336 			(rdma_ah_get_path_bits(&qp->remote_ah_attr) &
337 			((1 << ppd->lmc) - 1));
338 
339 	hfi1_make_16b_hdr(&ps->s_txreq->phdr.hdr.opah,
340 			  slid,
341 			  opa_get_lid(rdma_ah_get_dlid(&qp->remote_ah_attr),
342 				      16B),
343 			  (ps->s_txreq->hdr_dwords + nwords) >> 1,
344 			  pkey, becn, 0, l4, priv->s_sc);
345 }
346 
347 /**
348  * hfi1_make_ruc_header_9B - build a 9B header
349  * @qp: the queue pair
350  * @ohdr: a pointer to the destination header memory
351  * @bth0: bth0 passed in from the RC/UC builder
352  * @bth1: bth1 passed in from the RC/UC builder
353  * @bth2: bth2 passed in from the RC/UC builder
354  * @middle: non zero implies indicates ahg "could" be used
355  * @ps: the current packet state
356  *
357  * This routine may disarm ahg under these situations:
358  * - packet needs a GRH
359  * - BECN needed
360  * - migration state not IB_MIG_MIGRATED
361  */
362 static inline void hfi1_make_ruc_header_9B(struct rvt_qp *qp,
363 					   struct ib_other_headers *ohdr,
364 					   u32 bth0, u32 bth1, u32 bth2,
365 					   int middle,
366 					   struct hfi1_pkt_state *ps)
367 {
368 	struct hfi1_qp_priv *priv = qp->priv;
369 	struct hfi1_ibport *ibp = ps->ibp;
370 	u16 pkey = hfi1_get_pkey(ibp, qp->s_pkey_index);
371 	u16 lrh0 = HFI1_LRH_BTH;
372 	u8 extra_bytes = -ps->s_txreq->s_cur_size & 3;
373 	u32 nwords = SIZE_OF_CRC + ((ps->s_txreq->s_cur_size +
374 					 extra_bytes) >> 2);
375 
376 	if (unlikely(rdma_ah_get_ah_flags(&qp->remote_ah_attr) & IB_AH_GRH)) {
377 		struct ib_grh *grh = &ps->s_txreq->phdr.hdr.ibh.u.l.grh;
378 
379 		lrh0 = HFI1_LRH_GRH;
380 		ps->s_txreq->hdr_dwords +=
381 			hfi1_make_grh(ibp, grh,
382 				      rdma_ah_read_grh(&qp->remote_ah_attr),
383 				      ps->s_txreq->hdr_dwords - LRH_9B_DWORDS,
384 				      nwords);
385 		middle = 0;
386 	}
387 	lrh0 |= (priv->s_sc & 0xf) << 12 |
388 		(rdma_ah_get_sl(&qp->remote_ah_attr) & 0xf) << 4;
389 
390 	if (qp->s_mig_state == IB_MIG_MIGRATED)
391 		bth0 |= IB_BTH_MIG_REQ;
392 	else
393 		middle = 0;
394 
395 	if (qp->s_flags & RVT_S_ECN) {
396 		qp->s_flags &= ~RVT_S_ECN;
397 		/* we recently received a FECN, so return a BECN */
398 		bth1 |= (IB_BECN_MASK << IB_BECN_SHIFT);
399 		middle = 0;
400 	}
401 	if (middle)
402 		build_ahg(qp, bth2);
403 	else
404 		qp->s_flags &= ~HFI1_S_AHG_VALID;
405 
406 	bth0 |= pkey;
407 	bth0 |= extra_bytes << 20;
408 	hfi1_make_ruc_bth(qp, ohdr, bth0, bth1, bth2);
409 	hfi1_make_ib_hdr(&ps->s_txreq->phdr.hdr.ibh,
410 			 lrh0,
411 			 ps->s_txreq->hdr_dwords + nwords,
412 			 opa_get_lid(rdma_ah_get_dlid(&qp->remote_ah_attr), 9B),
413 			 ppd_from_ibp(ibp)->lid |
414 				rdma_ah_get_path_bits(&qp->remote_ah_attr));
415 }
416 
417 typedef void (*hfi1_make_ruc_hdr)(struct rvt_qp *qp,
418 				  struct ib_other_headers *ohdr,
419 				  u32 bth0, u32 bth1, u32 bth2, int middle,
420 				  struct hfi1_pkt_state *ps);
421 
422 /* We support only two types - 9B and 16B for now */
423 static const hfi1_make_ruc_hdr hfi1_ruc_header_tbl[2] = {
424 	[HFI1_PKT_TYPE_9B] = &hfi1_make_ruc_header_9B,
425 	[HFI1_PKT_TYPE_16B] = &hfi1_make_ruc_header_16B
426 };
427 
428 void hfi1_make_ruc_header(struct rvt_qp *qp, struct ib_other_headers *ohdr,
429 			  u32 bth0, u32 bth1, u32 bth2, int middle,
430 			  struct hfi1_pkt_state *ps)
431 {
432 	struct hfi1_qp_priv *priv = qp->priv;
433 
434 	/*
435 	 * reset s_ahg/AHG fields
436 	 *
437 	 * This insures that the ahgentry/ahgcount
438 	 * are at a non-AHG default to protect
439 	 * build_verbs_tx_desc() from using
440 	 * an include ahgidx.
441 	 *
442 	 * build_ahg() will modify as appropriate
443 	 * to use the AHG feature.
444 	 */
445 	priv->s_ahg->tx_flags = 0;
446 	priv->s_ahg->ahgcount = 0;
447 	priv->s_ahg->ahgidx = 0;
448 
449 	/* Make the appropriate header */
450 	hfi1_ruc_header_tbl[priv->hdr_type](qp, ohdr, bth0, bth1, bth2, middle,
451 					    ps);
452 }
453 
454 /* when sending, force a reschedule every one of these periods */
455 #define SEND_RESCHED_TIMEOUT (5 * HZ)  /* 5s in jiffies */
456 
457 /**
458  * hfi1_schedule_send_yield - test for a yield required for QP
459  * send engine
460  * @qp: a pointer to QP
461  * @ps: a pointer to a structure with commonly lookup values for
462  *      the the send engine progress
463  * @tid: true if it is the tid leg
464  *
465  * This routine checks if the time slice for the QP has expired
466  * for RC QPs, if so an additional work entry is queued. At this
467  * point, other QPs have an opportunity to be scheduled. It
468  * returns true if a yield is required, otherwise, false
469  * is returned.
470  */
471 bool hfi1_schedule_send_yield(struct rvt_qp *qp, struct hfi1_pkt_state *ps,
472 			      bool tid)
473 {
474 	ps->pkts_sent = true;
475 
476 	if (unlikely(time_after(jiffies, ps->timeout))) {
477 		if (!ps->in_thread ||
478 		    workqueue_congested(ps->cpu, ps->ppd->hfi1_wq)) {
479 			spin_lock_irqsave(&qp->s_lock, ps->flags);
480 			if (!tid) {
481 				qp->s_flags &= ~RVT_S_BUSY;
482 				hfi1_schedule_send(qp);
483 			} else {
484 				struct hfi1_qp_priv *priv = qp->priv;
485 
486 				if (priv->s_flags &
487 				    HFI1_S_TID_BUSY_SET) {
488 					qp->s_flags &= ~RVT_S_BUSY;
489 					priv->s_flags &=
490 						~(HFI1_S_TID_BUSY_SET |
491 						  RVT_S_BUSY);
492 				} else {
493 					priv->s_flags &= ~RVT_S_BUSY;
494 				}
495 				hfi1_schedule_tid_send(qp);
496 			}
497 
498 			spin_unlock_irqrestore(&qp->s_lock, ps->flags);
499 			this_cpu_inc(*ps->ppd->dd->send_schedule);
500 			trace_hfi1_rc_expired_time_slice(qp, true);
501 			return true;
502 		}
503 
504 		cond_resched();
505 		this_cpu_inc(*ps->ppd->dd->send_schedule);
506 		ps->timeout = jiffies + ps->timeout_int;
507 	}
508 
509 	trace_hfi1_rc_expired_time_slice(qp, false);
510 	return false;
511 }
512 
513 void hfi1_do_send_from_rvt(struct rvt_qp *qp)
514 {
515 	hfi1_do_send(qp, false);
516 }
517 
518 void _hfi1_do_send(struct work_struct *work)
519 {
520 	struct iowait_work *w = container_of(work, struct iowait_work, iowork);
521 	struct rvt_qp *qp = iowait_to_qp(w->iow);
522 
523 	hfi1_do_send(qp, true);
524 }
525 
526 /**
527  * hfi1_do_send - perform a send on a QP
528  * @qp: a pointer to the QP
529  * @in_thread: true if in a workqueue thread
530  *
531  * Process entries in the send work queue until credit or queue is
532  * exhausted.  Only allow one CPU to send a packet per QP.
533  * Otherwise, two threads could send packets out of order.
534  */
535 void hfi1_do_send(struct rvt_qp *qp, bool in_thread)
536 {
537 	struct hfi1_pkt_state ps;
538 	struct hfi1_qp_priv *priv = qp->priv;
539 	int (*make_req)(struct rvt_qp *qp, struct hfi1_pkt_state *ps);
540 
541 	ps.dev = to_idev(qp->ibqp.device);
542 	ps.ibp = to_iport(qp->ibqp.device, qp->port_num);
543 	ps.ppd = ppd_from_ibp(ps.ibp);
544 	ps.in_thread = in_thread;
545 	ps.wait = iowait_get_ib_work(&priv->s_iowait);
546 
547 	trace_hfi1_rc_do_send(qp, in_thread);
548 
549 	switch (qp->ibqp.qp_type) {
550 	case IB_QPT_RC:
551 		if (!loopback && ((rdma_ah_get_dlid(&qp->remote_ah_attr) &
552 				   ~((1 << ps.ppd->lmc) - 1)) ==
553 				  ps.ppd->lid)) {
554 			rvt_ruc_loopback(qp);
555 			return;
556 		}
557 		make_req = hfi1_make_rc_req;
558 		ps.timeout_int = qp->timeout_jiffies;
559 		break;
560 	case IB_QPT_UC:
561 		if (!loopback && ((rdma_ah_get_dlid(&qp->remote_ah_attr) &
562 				   ~((1 << ps.ppd->lmc) - 1)) ==
563 				  ps.ppd->lid)) {
564 			rvt_ruc_loopback(qp);
565 			return;
566 		}
567 		make_req = hfi1_make_uc_req;
568 		ps.timeout_int = SEND_RESCHED_TIMEOUT;
569 		break;
570 	default:
571 		make_req = hfi1_make_ud_req;
572 		ps.timeout_int = SEND_RESCHED_TIMEOUT;
573 	}
574 
575 	spin_lock_irqsave(&qp->s_lock, ps.flags);
576 
577 	/* Return if we are already busy processing a work request. */
578 	if (!hfi1_send_ok(qp)) {
579 		if (qp->s_flags & HFI1_S_ANY_WAIT_IO)
580 			iowait_set_flag(&priv->s_iowait, IOWAIT_PENDING_IB);
581 		spin_unlock_irqrestore(&qp->s_lock, ps.flags);
582 		return;
583 	}
584 
585 	qp->s_flags |= RVT_S_BUSY;
586 
587 	ps.timeout_int = ps.timeout_int / 8;
588 	ps.timeout = jiffies + ps.timeout_int;
589 	ps.cpu = priv->s_sde ? priv->s_sde->cpu :
590 			cpumask_first(cpumask_of_node(ps.ppd->dd->node));
591 	ps.pkts_sent = false;
592 
593 	/* insure a pre-built packet is handled  */
594 	ps.s_txreq = get_waiting_verbs_txreq(ps.wait);
595 	do {
596 		/* Check for a constructed packet to be sent. */
597 		if (ps.s_txreq) {
598 			if (priv->s_flags & HFI1_S_TID_BUSY_SET)
599 				qp->s_flags |= RVT_S_BUSY;
600 			spin_unlock_irqrestore(&qp->s_lock, ps.flags);
601 			/*
602 			 * If the packet cannot be sent now, return and
603 			 * the send engine will be woken up later.
604 			 */
605 			if (hfi1_verbs_send(qp, &ps))
606 				return;
607 
608 			/* allow other tasks to run */
609 			if (hfi1_schedule_send_yield(qp, &ps, false))
610 				return;
611 
612 			spin_lock_irqsave(&qp->s_lock, ps.flags);
613 		}
614 	} while (make_req(qp, &ps));
615 	iowait_starve_clear(ps.pkts_sent, &priv->s_iowait);
616 	spin_unlock_irqrestore(&qp->s_lock, ps.flags);
617 }
618