xref: /openbmc/linux/drivers/infiniband/hw/hfi1/rc.c (revision cbdf59ad)
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/io.h>
49 #include <rdma/rdma_vt.h>
50 #include <rdma/rdmavt_qp.h>
51 
52 #include "hfi.h"
53 #include "qp.h"
54 #include "rc.h"
55 #include "verbs_txreq.h"
56 #include "trace.h"
57 
58 struct rvt_ack_entry *find_prev_entry(struct rvt_qp *qp, u32 psn, u8 *prev,
59 				      u8 *prev_ack, bool *scheduled)
60 	__must_hold(&qp->s_lock)
61 {
62 	struct rvt_ack_entry *e = NULL;
63 	u8 i, p;
64 	bool s = true;
65 
66 	for (i = qp->r_head_ack_queue; ; i = p) {
67 		if (i == qp->s_tail_ack_queue)
68 			s = false;
69 		if (i)
70 			p = i - 1;
71 		else
72 			p = rvt_size_atomic(ib_to_rvt(qp->ibqp.device));
73 		if (p == qp->r_head_ack_queue) {
74 			e = NULL;
75 			break;
76 		}
77 		e = &qp->s_ack_queue[p];
78 		if (!e->opcode) {
79 			e = NULL;
80 			break;
81 		}
82 		if (cmp_psn(psn, e->psn) >= 0) {
83 			if (p == qp->s_tail_ack_queue &&
84 			    cmp_psn(psn, e->lpsn) <= 0)
85 				s = false;
86 			break;
87 		}
88 	}
89 	if (prev)
90 		*prev = p;
91 	if (prev_ack)
92 		*prev_ack = i;
93 	if (scheduled)
94 		*scheduled = s;
95 	return e;
96 }
97 
98 /**
99  * make_rc_ack - construct a response packet (ACK, NAK, or RDMA read)
100  * @dev: the device for this QP
101  * @qp: a pointer to the QP
102  * @ohdr: a pointer to the IB header being constructed
103  * @ps: the xmit packet state
104  *
105  * Return 1 if constructed; otherwise, return 0.
106  * Note that we are in the responder's side of the QP context.
107  * Note the QP s_lock must be held.
108  */
109 static int make_rc_ack(struct hfi1_ibdev *dev, struct rvt_qp *qp,
110 		       struct ib_other_headers *ohdr,
111 		       struct hfi1_pkt_state *ps)
112 {
113 	struct rvt_ack_entry *e;
114 	u32 hwords, hdrlen;
115 	u32 len = 0;
116 	u32 bth0 = 0, bth2 = 0;
117 	u32 bth1 = qp->remote_qpn | (HFI1_CAP_IS_KSET(OPFN) << IB_BTHE_E_SHIFT);
118 	int middle = 0;
119 	u32 pmtu = qp->pmtu;
120 	struct hfi1_qp_priv *qpriv = qp->priv;
121 	bool last_pkt;
122 	u32 delta;
123 	u8 next = qp->s_tail_ack_queue;
124 	struct tid_rdma_request *req;
125 
126 	trace_hfi1_rsp_make_rc_ack(qp, 0);
127 	lockdep_assert_held(&qp->s_lock);
128 	/* Don't send an ACK if we aren't supposed to. */
129 	if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK))
130 		goto bail;
131 
132 	if (qpriv->hdr_type == HFI1_PKT_TYPE_9B)
133 		/* header size in 32-bit words LRH+BTH = (8+12)/4. */
134 		hwords = 5;
135 	else
136 		/* header size in 32-bit words 16B LRH+BTH = (16+12)/4. */
137 		hwords = 7;
138 
139 	switch (qp->s_ack_state) {
140 	case OP(RDMA_READ_RESPONSE_LAST):
141 	case OP(RDMA_READ_RESPONSE_ONLY):
142 		e = &qp->s_ack_queue[qp->s_tail_ack_queue];
143 		release_rdma_sge_mr(e);
144 		/* FALLTHROUGH */
145 	case OP(ATOMIC_ACKNOWLEDGE):
146 		/*
147 		 * We can increment the tail pointer now that the last
148 		 * response has been sent instead of only being
149 		 * constructed.
150 		 */
151 		if (++next > rvt_size_atomic(&dev->rdi))
152 			next = 0;
153 		/*
154 		 * Only advance the s_acked_ack_queue pointer if there
155 		 * have been no TID RDMA requests.
156 		 */
157 		e = &qp->s_ack_queue[qp->s_tail_ack_queue];
158 		if (e->opcode != TID_OP(WRITE_REQ) &&
159 		    qp->s_acked_ack_queue == qp->s_tail_ack_queue)
160 			qp->s_acked_ack_queue = next;
161 		qp->s_tail_ack_queue = next;
162 		trace_hfi1_rsp_make_rc_ack(qp, e->psn);
163 		/* FALLTHROUGH */
164 	case OP(SEND_ONLY):
165 	case OP(ACKNOWLEDGE):
166 		/* Check for no next entry in the queue. */
167 		if (qp->r_head_ack_queue == qp->s_tail_ack_queue) {
168 			if (qp->s_flags & RVT_S_ACK_PENDING)
169 				goto normal;
170 			goto bail;
171 		}
172 
173 		e = &qp->s_ack_queue[qp->s_tail_ack_queue];
174 		/* Check for tid write fence */
175 		if ((qpriv->s_flags & HFI1_R_TID_WAIT_INTERLCK) ||
176 		    hfi1_tid_rdma_ack_interlock(qp, e)) {
177 			iowait_set_flag(&qpriv->s_iowait, IOWAIT_PENDING_IB);
178 			goto bail;
179 		}
180 		if (e->opcode == OP(RDMA_READ_REQUEST)) {
181 			/*
182 			 * If a RDMA read response is being resent and
183 			 * we haven't seen the duplicate request yet,
184 			 * then stop sending the remaining responses the
185 			 * responder has seen until the requester re-sends it.
186 			 */
187 			len = e->rdma_sge.sge_length;
188 			if (len && !e->rdma_sge.mr) {
189 				if (qp->s_acked_ack_queue ==
190 				    qp->s_tail_ack_queue)
191 					qp->s_acked_ack_queue =
192 						qp->r_head_ack_queue;
193 				qp->s_tail_ack_queue = qp->r_head_ack_queue;
194 				goto bail;
195 			}
196 			/* Copy SGE state in case we need to resend */
197 			ps->s_txreq->mr = e->rdma_sge.mr;
198 			if (ps->s_txreq->mr)
199 				rvt_get_mr(ps->s_txreq->mr);
200 			qp->s_ack_rdma_sge.sge = e->rdma_sge;
201 			qp->s_ack_rdma_sge.num_sge = 1;
202 			ps->s_txreq->ss = &qp->s_ack_rdma_sge;
203 			if (len > pmtu) {
204 				len = pmtu;
205 				qp->s_ack_state = OP(RDMA_READ_RESPONSE_FIRST);
206 			} else {
207 				qp->s_ack_state = OP(RDMA_READ_RESPONSE_ONLY);
208 				e->sent = 1;
209 			}
210 			ohdr->u.aeth = rvt_compute_aeth(qp);
211 			hwords++;
212 			qp->s_ack_rdma_psn = e->psn;
213 			bth2 = mask_psn(qp->s_ack_rdma_psn++);
214 		} else if (e->opcode == TID_OP(WRITE_REQ)) {
215 			/*
216 			 * If a TID RDMA WRITE RESP is being resent, we have to
217 			 * wait for the actual request. All requests that are to
218 			 * be resent will have their state set to
219 			 * TID_REQUEST_RESEND. When the new request arrives, the
220 			 * state will be changed to TID_REQUEST_RESEND_ACTIVE.
221 			 */
222 			req = ack_to_tid_req(e);
223 			if (req->state == TID_REQUEST_RESEND ||
224 			    req->state == TID_REQUEST_INIT_RESEND)
225 				goto bail;
226 			qp->s_ack_state = TID_OP(WRITE_RESP);
227 			qp->s_ack_rdma_psn = mask_psn(e->psn + req->cur_seg);
228 			goto write_resp;
229 		} else if (e->opcode == TID_OP(READ_REQ)) {
230 			/*
231 			 * If a TID RDMA read response is being resent and
232 			 * we haven't seen the duplicate request yet,
233 			 * then stop sending the remaining responses the
234 			 * responder has seen until the requester re-sends it.
235 			 */
236 			len = e->rdma_sge.sge_length;
237 			if (len && !e->rdma_sge.mr) {
238 				if (qp->s_acked_ack_queue ==
239 				    qp->s_tail_ack_queue)
240 					qp->s_acked_ack_queue =
241 						qp->r_head_ack_queue;
242 				qp->s_tail_ack_queue = qp->r_head_ack_queue;
243 				goto bail;
244 			}
245 			/* Copy SGE state in case we need to resend */
246 			ps->s_txreq->mr = e->rdma_sge.mr;
247 			if (ps->s_txreq->mr)
248 				rvt_get_mr(ps->s_txreq->mr);
249 			qp->s_ack_rdma_sge.sge = e->rdma_sge;
250 			qp->s_ack_rdma_sge.num_sge = 1;
251 			qp->s_ack_state = TID_OP(READ_RESP);
252 			goto read_resp;
253 		} else {
254 			/* COMPARE_SWAP or FETCH_ADD */
255 			ps->s_txreq->ss = NULL;
256 			len = 0;
257 			qp->s_ack_state = OP(ATOMIC_ACKNOWLEDGE);
258 			ohdr->u.at.aeth = rvt_compute_aeth(qp);
259 			ib_u64_put(e->atomic_data, &ohdr->u.at.atomic_ack_eth);
260 			hwords += sizeof(ohdr->u.at) / sizeof(u32);
261 			bth2 = mask_psn(e->psn);
262 			e->sent = 1;
263 		}
264 		trace_hfi1_tid_write_rsp_make_rc_ack(qp);
265 		bth0 = qp->s_ack_state << 24;
266 		break;
267 
268 	case OP(RDMA_READ_RESPONSE_FIRST):
269 		qp->s_ack_state = OP(RDMA_READ_RESPONSE_MIDDLE);
270 		/* FALLTHROUGH */
271 	case OP(RDMA_READ_RESPONSE_MIDDLE):
272 		ps->s_txreq->ss = &qp->s_ack_rdma_sge;
273 		ps->s_txreq->mr = qp->s_ack_rdma_sge.sge.mr;
274 		if (ps->s_txreq->mr)
275 			rvt_get_mr(ps->s_txreq->mr);
276 		len = qp->s_ack_rdma_sge.sge.sge_length;
277 		if (len > pmtu) {
278 			len = pmtu;
279 			middle = HFI1_CAP_IS_KSET(SDMA_AHG);
280 		} else {
281 			ohdr->u.aeth = rvt_compute_aeth(qp);
282 			hwords++;
283 			qp->s_ack_state = OP(RDMA_READ_RESPONSE_LAST);
284 			e = &qp->s_ack_queue[qp->s_tail_ack_queue];
285 			e->sent = 1;
286 		}
287 		bth0 = qp->s_ack_state << 24;
288 		bth2 = mask_psn(qp->s_ack_rdma_psn++);
289 		break;
290 
291 	case TID_OP(WRITE_RESP):
292 write_resp:
293 		/*
294 		 * 1. Check if RVT_S_ACK_PENDING is set. If yes,
295 		 *    goto normal.
296 		 * 2. Attempt to allocate TID resources.
297 		 * 3. Remove RVT_S_RESP_PENDING flags from s_flags
298 		 * 4. If resources not available:
299 		 *    4.1 Set RVT_S_WAIT_TID_SPACE
300 		 *    4.2 Queue QP on RCD TID queue
301 		 *    4.3 Put QP on iowait list.
302 		 *    4.4 Build IB RNR NAK with appropriate timeout value
303 		 *    4.5 Return indication progress made.
304 		 * 5. If resources are available:
305 		 *    5.1 Program HW flow CSRs
306 		 *    5.2 Build TID RDMA WRITE RESP packet
307 		 *    5.3 If more resources needed, do 2.1 - 2.3.
308 		 *    5.4 Wake up next QP on RCD TID queue.
309 		 *    5.5 Return indication progress made.
310 		 */
311 
312 		e = &qp->s_ack_queue[qp->s_tail_ack_queue];
313 		req = ack_to_tid_req(e);
314 
315 		/*
316 		 * Send scheduled RNR NAK's. RNR NAK's need to be sent at
317 		 * segment boundaries, not at request boundaries. Don't change
318 		 * s_ack_state because we are still in the middle of a request
319 		 */
320 		if (qpriv->rnr_nak_state == TID_RNR_NAK_SEND &&
321 		    qp->s_tail_ack_queue == qpriv->r_tid_alloc &&
322 		    req->cur_seg == req->alloc_seg) {
323 			qpriv->rnr_nak_state = TID_RNR_NAK_SENT;
324 			goto normal_no_state;
325 		}
326 
327 		bth2 = mask_psn(qp->s_ack_rdma_psn);
328 		hdrlen = hfi1_build_tid_rdma_write_resp(qp, e, ohdr, &bth1,
329 							bth2, &len,
330 							&ps->s_txreq->ss);
331 		if (!hdrlen)
332 			return 0;
333 
334 		hwords += hdrlen;
335 		bth0 = qp->s_ack_state << 24;
336 		qp->s_ack_rdma_psn++;
337 		trace_hfi1_tid_req_make_rc_ack_write(qp, 0, e->opcode, e->psn,
338 						     e->lpsn, req);
339 		if (req->cur_seg != req->total_segs)
340 			break;
341 
342 		e->sent = 1;
343 		/* Do not free e->rdma_sge until all data are received */
344 		qp->s_ack_state = OP(ATOMIC_ACKNOWLEDGE);
345 		break;
346 
347 	case TID_OP(READ_RESP):
348 read_resp:
349 		e = &qp->s_ack_queue[qp->s_tail_ack_queue];
350 		ps->s_txreq->ss = &qp->s_ack_rdma_sge;
351 		delta = hfi1_build_tid_rdma_read_resp(qp, e, ohdr, &bth0,
352 						      &bth1, &bth2, &len,
353 						      &last_pkt);
354 		if (delta == 0)
355 			goto error_qp;
356 		hwords += delta;
357 		if (last_pkt) {
358 			e->sent = 1;
359 			/*
360 			 * Increment qp->s_tail_ack_queue through s_ack_state
361 			 * transition.
362 			 */
363 			qp->s_ack_state = OP(RDMA_READ_RESPONSE_LAST);
364 		}
365 		break;
366 	case TID_OP(READ_REQ):
367 		goto bail;
368 
369 	default:
370 normal:
371 		/*
372 		 * Send a regular ACK.
373 		 * Set the s_ack_state so we wait until after sending
374 		 * the ACK before setting s_ack_state to ACKNOWLEDGE
375 		 * (see above).
376 		 */
377 		qp->s_ack_state = OP(SEND_ONLY);
378 normal_no_state:
379 		if (qp->s_nak_state)
380 			ohdr->u.aeth =
381 				cpu_to_be32((qp->r_msn & IB_MSN_MASK) |
382 					    (qp->s_nak_state <<
383 					     IB_AETH_CREDIT_SHIFT));
384 		else
385 			ohdr->u.aeth = rvt_compute_aeth(qp);
386 		hwords++;
387 		len = 0;
388 		bth0 = OP(ACKNOWLEDGE) << 24;
389 		bth2 = mask_psn(qp->s_ack_psn);
390 		qp->s_flags &= ~RVT_S_ACK_PENDING;
391 		ps->s_txreq->txreq.flags |= SDMA_TXREQ_F_VIP;
392 		ps->s_txreq->ss = NULL;
393 	}
394 	qp->s_rdma_ack_cnt++;
395 	ps->s_txreq->sde = qpriv->s_sde;
396 	ps->s_txreq->s_cur_size = len;
397 	ps->s_txreq->hdr_dwords = hwords;
398 	hfi1_make_ruc_header(qp, ohdr, bth0, bth1, bth2, middle, ps);
399 	return 1;
400 error_qp:
401 	spin_unlock_irqrestore(&qp->s_lock, ps->flags);
402 	spin_lock_irqsave(&qp->r_lock, ps->flags);
403 	spin_lock(&qp->s_lock);
404 	rvt_error_qp(qp, IB_WC_WR_FLUSH_ERR);
405 	spin_unlock(&qp->s_lock);
406 	spin_unlock_irqrestore(&qp->r_lock, ps->flags);
407 	spin_lock_irqsave(&qp->s_lock, ps->flags);
408 bail:
409 	qp->s_ack_state = OP(ACKNOWLEDGE);
410 	/*
411 	 * Ensure s_rdma_ack_cnt changes are committed prior to resetting
412 	 * RVT_S_RESP_PENDING
413 	 */
414 	smp_wmb();
415 	qp->s_flags &= ~(RVT_S_RESP_PENDING
416 				| RVT_S_ACK_PENDING
417 				| HFI1_S_AHG_VALID);
418 	return 0;
419 }
420 
421 /**
422  * hfi1_make_rc_req - construct a request packet (SEND, RDMA r/w, ATOMIC)
423  * @qp: a pointer to the QP
424  *
425  * Assumes s_lock is held.
426  *
427  * Return 1 if constructed; otherwise, return 0.
428  */
429 int hfi1_make_rc_req(struct rvt_qp *qp, struct hfi1_pkt_state *ps)
430 {
431 	struct hfi1_qp_priv *priv = qp->priv;
432 	struct hfi1_ibdev *dev = to_idev(qp->ibqp.device);
433 	struct ib_other_headers *ohdr;
434 	struct rvt_sge_state *ss = NULL;
435 	struct rvt_swqe *wqe;
436 	struct hfi1_swqe_priv *wpriv;
437 	struct tid_rdma_request *req = NULL;
438 	/* header size in 32-bit words LRH+BTH = (8+12)/4. */
439 	u32 hwords = 5;
440 	u32 len = 0;
441 	u32 bth0 = 0, bth2 = 0;
442 	u32 bth1 = qp->remote_qpn | (HFI1_CAP_IS_KSET(OPFN) << IB_BTHE_E_SHIFT);
443 	u32 pmtu = qp->pmtu;
444 	char newreq;
445 	int middle = 0;
446 	int delta;
447 	struct tid_rdma_flow *flow = NULL;
448 	struct tid_rdma_params *remote;
449 
450 	trace_hfi1_sender_make_rc_req(qp);
451 	lockdep_assert_held(&qp->s_lock);
452 	ps->s_txreq = get_txreq(ps->dev, qp);
453 	if (!ps->s_txreq)
454 		goto bail_no_tx;
455 
456 	if (priv->hdr_type == HFI1_PKT_TYPE_9B) {
457 		/* header size in 32-bit words LRH+BTH = (8+12)/4. */
458 		hwords = 5;
459 		if (rdma_ah_get_ah_flags(&qp->remote_ah_attr) & IB_AH_GRH)
460 			ohdr = &ps->s_txreq->phdr.hdr.ibh.u.l.oth;
461 		else
462 			ohdr = &ps->s_txreq->phdr.hdr.ibh.u.oth;
463 	} else {
464 		/* header size in 32-bit words 16B LRH+BTH = (16+12)/4. */
465 		hwords = 7;
466 		if ((rdma_ah_get_ah_flags(&qp->remote_ah_attr) & IB_AH_GRH) &&
467 		    (hfi1_check_mcast(rdma_ah_get_dlid(&qp->remote_ah_attr))))
468 			ohdr = &ps->s_txreq->phdr.hdr.opah.u.l.oth;
469 		else
470 			ohdr = &ps->s_txreq->phdr.hdr.opah.u.oth;
471 	}
472 
473 	/* Sending responses has higher priority over sending requests. */
474 	if ((qp->s_flags & RVT_S_RESP_PENDING) &&
475 	    make_rc_ack(dev, qp, ohdr, ps))
476 		return 1;
477 
478 	if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_SEND_OK)) {
479 		if (!(ib_rvt_state_ops[qp->state] & RVT_FLUSH_SEND))
480 			goto bail;
481 		/* We are in the error state, flush the work request. */
482 		if (qp->s_last == READ_ONCE(qp->s_head))
483 			goto bail;
484 		/* If DMAs are in progress, we can't flush immediately. */
485 		if (iowait_sdma_pending(&priv->s_iowait)) {
486 			qp->s_flags |= RVT_S_WAIT_DMA;
487 			goto bail;
488 		}
489 		clear_ahg(qp);
490 		wqe = rvt_get_swqe_ptr(qp, qp->s_last);
491 		hfi1_trdma_send_complete(qp, wqe, qp->s_last != qp->s_acked ?
492 					 IB_WC_SUCCESS : IB_WC_WR_FLUSH_ERR);
493 		/* will get called again */
494 		goto done_free_tx;
495 	}
496 
497 	if (qp->s_flags & (RVT_S_WAIT_RNR | RVT_S_WAIT_ACK | HFI1_S_WAIT_HALT))
498 		goto bail;
499 
500 	if (cmp_psn(qp->s_psn, qp->s_sending_hpsn) <= 0) {
501 		if (cmp_psn(qp->s_sending_psn, qp->s_sending_hpsn) <= 0) {
502 			qp->s_flags |= RVT_S_WAIT_PSN;
503 			goto bail;
504 		}
505 		qp->s_sending_psn = qp->s_psn;
506 		qp->s_sending_hpsn = qp->s_psn - 1;
507 	}
508 
509 	/* Send a request. */
510 	wqe = rvt_get_swqe_ptr(qp, qp->s_cur);
511 check_s_state:
512 	switch (qp->s_state) {
513 	default:
514 		if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_NEXT_SEND_OK))
515 			goto bail;
516 		/*
517 		 * Resend an old request or start a new one.
518 		 *
519 		 * We keep track of the current SWQE so that
520 		 * we don't reset the "furthest progress" state
521 		 * if we need to back up.
522 		 */
523 		newreq = 0;
524 		if (qp->s_cur == qp->s_tail) {
525 			/* Check if send work queue is empty. */
526 			if (qp->s_tail == READ_ONCE(qp->s_head)) {
527 				clear_ahg(qp);
528 				goto bail;
529 			}
530 			/*
531 			 * If a fence is requested, wait for previous
532 			 * RDMA read and atomic operations to finish.
533 			 * However, there is no need to guard against
534 			 * TID RDMA READ after TID RDMA READ.
535 			 */
536 			if ((wqe->wr.send_flags & IB_SEND_FENCE) &&
537 			    qp->s_num_rd_atomic &&
538 			    (wqe->wr.opcode != IB_WR_TID_RDMA_READ ||
539 			     priv->pending_tid_r_segs < qp->s_num_rd_atomic)) {
540 				qp->s_flags |= RVT_S_WAIT_FENCE;
541 				goto bail;
542 			}
543 			/*
544 			 * Local operations are processed immediately
545 			 * after all prior requests have completed
546 			 */
547 			if (wqe->wr.opcode == IB_WR_REG_MR ||
548 			    wqe->wr.opcode == IB_WR_LOCAL_INV) {
549 				int local_ops = 0;
550 				int err = 0;
551 
552 				if (qp->s_last != qp->s_cur)
553 					goto bail;
554 				if (++qp->s_cur == qp->s_size)
555 					qp->s_cur = 0;
556 				if (++qp->s_tail == qp->s_size)
557 					qp->s_tail = 0;
558 				if (!(wqe->wr.send_flags &
559 				      RVT_SEND_COMPLETION_ONLY)) {
560 					err = rvt_invalidate_rkey(
561 						qp,
562 						wqe->wr.ex.invalidate_rkey);
563 					local_ops = 1;
564 				}
565 				rvt_send_complete(qp, wqe,
566 						  err ? IB_WC_LOC_PROT_ERR
567 						      : IB_WC_SUCCESS);
568 				if (local_ops)
569 					atomic_dec(&qp->local_ops_pending);
570 				goto done_free_tx;
571 			}
572 
573 			newreq = 1;
574 			qp->s_psn = wqe->psn;
575 		}
576 		/*
577 		 * Note that we have to be careful not to modify the
578 		 * original work request since we may need to resend
579 		 * it.
580 		 */
581 		len = wqe->length;
582 		ss = &qp->s_sge;
583 		bth2 = mask_psn(qp->s_psn);
584 
585 		/*
586 		 * Interlock between various IB requests and TID RDMA
587 		 * if necessary.
588 		 */
589 		if ((priv->s_flags & HFI1_S_TID_WAIT_INTERLCK) ||
590 		    hfi1_tid_rdma_wqe_interlock(qp, wqe))
591 			goto bail;
592 
593 		switch (wqe->wr.opcode) {
594 		case IB_WR_SEND:
595 		case IB_WR_SEND_WITH_IMM:
596 		case IB_WR_SEND_WITH_INV:
597 			/* If no credit, return. */
598 			if (!(qp->s_flags & RVT_S_UNLIMITED_CREDIT) &&
599 			    rvt_cmp_msn(wqe->ssn, qp->s_lsn + 1) > 0) {
600 				qp->s_flags |= RVT_S_WAIT_SSN_CREDIT;
601 				goto bail;
602 			}
603 			if (len > pmtu) {
604 				qp->s_state = OP(SEND_FIRST);
605 				len = pmtu;
606 				break;
607 			}
608 			if (wqe->wr.opcode == IB_WR_SEND) {
609 				qp->s_state = OP(SEND_ONLY);
610 			} else if (wqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
611 				qp->s_state = OP(SEND_ONLY_WITH_IMMEDIATE);
612 				/* Immediate data comes after the BTH */
613 				ohdr->u.imm_data = wqe->wr.ex.imm_data;
614 				hwords += 1;
615 			} else {
616 				qp->s_state = OP(SEND_ONLY_WITH_INVALIDATE);
617 				/* Invalidate rkey comes after the BTH */
618 				ohdr->u.ieth = cpu_to_be32(
619 						wqe->wr.ex.invalidate_rkey);
620 				hwords += 1;
621 			}
622 			if (wqe->wr.send_flags & IB_SEND_SOLICITED)
623 				bth0 |= IB_BTH_SOLICITED;
624 			bth2 |= IB_BTH_REQ_ACK;
625 			if (++qp->s_cur == qp->s_size)
626 				qp->s_cur = 0;
627 			break;
628 
629 		case IB_WR_RDMA_WRITE:
630 			if (newreq && !(qp->s_flags & RVT_S_UNLIMITED_CREDIT))
631 				qp->s_lsn++;
632 			goto no_flow_control;
633 		case IB_WR_RDMA_WRITE_WITH_IMM:
634 			/* If no credit, return. */
635 			if (!(qp->s_flags & RVT_S_UNLIMITED_CREDIT) &&
636 			    rvt_cmp_msn(wqe->ssn, qp->s_lsn + 1) > 0) {
637 				qp->s_flags |= RVT_S_WAIT_SSN_CREDIT;
638 				goto bail;
639 			}
640 no_flow_control:
641 			put_ib_reth_vaddr(
642 				wqe->rdma_wr.remote_addr,
643 				&ohdr->u.rc.reth);
644 			ohdr->u.rc.reth.rkey =
645 				cpu_to_be32(wqe->rdma_wr.rkey);
646 			ohdr->u.rc.reth.length = cpu_to_be32(len);
647 			hwords += sizeof(struct ib_reth) / sizeof(u32);
648 			if (len > pmtu) {
649 				qp->s_state = OP(RDMA_WRITE_FIRST);
650 				len = pmtu;
651 				break;
652 			}
653 			if (wqe->wr.opcode == IB_WR_RDMA_WRITE) {
654 				qp->s_state = OP(RDMA_WRITE_ONLY);
655 			} else {
656 				qp->s_state =
657 					OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE);
658 				/* Immediate data comes after RETH */
659 				ohdr->u.rc.imm_data = wqe->wr.ex.imm_data;
660 				hwords += 1;
661 				if (wqe->wr.send_flags & IB_SEND_SOLICITED)
662 					bth0 |= IB_BTH_SOLICITED;
663 			}
664 			bth2 |= IB_BTH_REQ_ACK;
665 			if (++qp->s_cur == qp->s_size)
666 				qp->s_cur = 0;
667 			break;
668 
669 		case IB_WR_TID_RDMA_WRITE:
670 			if (newreq) {
671 				/*
672 				 * Limit the number of TID RDMA WRITE requests.
673 				 */
674 				if (atomic_read(&priv->n_tid_requests) >=
675 				    HFI1_TID_RDMA_WRITE_CNT)
676 					goto bail;
677 
678 				if (!(qp->s_flags & RVT_S_UNLIMITED_CREDIT))
679 					qp->s_lsn++;
680 			}
681 
682 			hwords += hfi1_build_tid_rdma_write_req(qp, wqe, ohdr,
683 								&bth1, &bth2,
684 								&len);
685 			ss = NULL;
686 			if (priv->s_tid_cur == HFI1_QP_WQE_INVALID) {
687 				priv->s_tid_cur = qp->s_cur;
688 				if (priv->s_tid_tail == HFI1_QP_WQE_INVALID) {
689 					priv->s_tid_tail = qp->s_cur;
690 					priv->s_state = TID_OP(WRITE_RESP);
691 				}
692 			} else if (priv->s_tid_cur == priv->s_tid_head) {
693 				struct rvt_swqe *__w;
694 				struct tid_rdma_request *__r;
695 
696 				__w = rvt_get_swqe_ptr(qp, priv->s_tid_cur);
697 				__r = wqe_to_tid_req(__w);
698 
699 				/*
700 				 * The s_tid_cur pointer is advanced to s_cur if
701 				 * any of the following conditions about the WQE
702 				 * to which s_ti_cur currently points to are
703 				 * satisfied:
704 				 *   1. The request is not a TID RDMA WRITE
705 				 *      request,
706 				 *   2. The request is in the INACTIVE or
707 				 *      COMPLETE states (TID RDMA READ requests
708 				 *      stay at INACTIVE and TID RDMA WRITE
709 				 *      transition to COMPLETE when done),
710 				 *   3. The request is in the ACTIVE or SYNC
711 				 *      state and the number of completed
712 				 *      segments is equal to the total segment
713 				 *      count.
714 				 *      (If ACTIVE, the request is waiting for
715 				 *       ACKs. If SYNC, the request has not
716 				 *       received any responses because it's
717 				 *       waiting on a sync point.)
718 				 */
719 				if (__w->wr.opcode != IB_WR_TID_RDMA_WRITE ||
720 				    __r->state == TID_REQUEST_INACTIVE ||
721 				    __r->state == TID_REQUEST_COMPLETE ||
722 				    ((__r->state == TID_REQUEST_ACTIVE ||
723 				      __r->state == TID_REQUEST_SYNC) &&
724 				     __r->comp_seg == __r->total_segs)) {
725 					if (priv->s_tid_tail ==
726 					    priv->s_tid_cur &&
727 					    priv->s_state ==
728 					    TID_OP(WRITE_DATA_LAST)) {
729 						priv->s_tid_tail = qp->s_cur;
730 						priv->s_state =
731 							TID_OP(WRITE_RESP);
732 					}
733 					priv->s_tid_cur = qp->s_cur;
734 				}
735 				/*
736 				 * A corner case: when the last TID RDMA WRITE
737 				 * request was completed, s_tid_head,
738 				 * s_tid_cur, and s_tid_tail all point to the
739 				 * same location. Other requests are posted and
740 				 * s_cur wraps around to the same location,
741 				 * where a new TID RDMA WRITE is posted. In
742 				 * this case, none of the indices need to be
743 				 * updated. However, the priv->s_state should.
744 				 */
745 				if (priv->s_tid_tail == qp->s_cur &&
746 				    priv->s_state == TID_OP(WRITE_DATA_LAST))
747 					priv->s_state = TID_OP(WRITE_RESP);
748 			}
749 			req = wqe_to_tid_req(wqe);
750 			if (newreq) {
751 				priv->s_tid_head = qp->s_cur;
752 				priv->pending_tid_w_resp += req->total_segs;
753 				atomic_inc(&priv->n_tid_requests);
754 				atomic_dec(&priv->n_requests);
755 			} else {
756 				req->state = TID_REQUEST_RESEND;
757 				req->comp_seg = delta_psn(bth2, wqe->psn);
758 				/*
759 				 * Pull back any segments since we are going
760 				 * to re-receive them.
761 				 */
762 				req->setup_head = req->clear_tail;
763 				priv->pending_tid_w_resp +=
764 					delta_psn(wqe->lpsn, bth2) + 1;
765 			}
766 
767 			trace_hfi1_tid_write_sender_make_req(qp, newreq);
768 			trace_hfi1_tid_req_make_req_write(qp, newreq,
769 							  wqe->wr.opcode,
770 							  wqe->psn, wqe->lpsn,
771 							  req);
772 			if (++qp->s_cur == qp->s_size)
773 				qp->s_cur = 0;
774 			break;
775 
776 		case IB_WR_RDMA_READ:
777 			/*
778 			 * Don't allow more operations to be started
779 			 * than the QP limits allow.
780 			 */
781 			if (qp->s_num_rd_atomic >=
782 			    qp->s_max_rd_atomic) {
783 				qp->s_flags |= RVT_S_WAIT_RDMAR;
784 				goto bail;
785 			}
786 			qp->s_num_rd_atomic++;
787 			if (newreq && !(qp->s_flags & RVT_S_UNLIMITED_CREDIT))
788 				qp->s_lsn++;
789 			put_ib_reth_vaddr(
790 				wqe->rdma_wr.remote_addr,
791 				&ohdr->u.rc.reth);
792 			ohdr->u.rc.reth.rkey =
793 				cpu_to_be32(wqe->rdma_wr.rkey);
794 			ohdr->u.rc.reth.length = cpu_to_be32(len);
795 			qp->s_state = OP(RDMA_READ_REQUEST);
796 			hwords += sizeof(ohdr->u.rc.reth) / sizeof(u32);
797 			ss = NULL;
798 			len = 0;
799 			bth2 |= IB_BTH_REQ_ACK;
800 			if (++qp->s_cur == qp->s_size)
801 				qp->s_cur = 0;
802 			break;
803 
804 		case IB_WR_TID_RDMA_READ:
805 			trace_hfi1_tid_read_sender_make_req(qp, newreq);
806 			wpriv = wqe->priv;
807 			req = wqe_to_tid_req(wqe);
808 			trace_hfi1_tid_req_make_req_read(qp, newreq,
809 							 wqe->wr.opcode,
810 							 wqe->psn, wqe->lpsn,
811 							 req);
812 			delta = cmp_psn(qp->s_psn, wqe->psn);
813 
814 			/*
815 			 * Don't allow more operations to be started
816 			 * than the QP limits allow. We could get here under
817 			 * three conditions; (1) It's a new request; (2) We are
818 			 * sending the second or later segment of a request,
819 			 * but the qp->s_state is set to OP(RDMA_READ_REQUEST)
820 			 * when the last segment of a previous request is
821 			 * received just before this; (3) We are re-sending a
822 			 * request.
823 			 */
824 			if (qp->s_num_rd_atomic >= qp->s_max_rd_atomic) {
825 				qp->s_flags |= RVT_S_WAIT_RDMAR;
826 				goto bail;
827 			}
828 			if (newreq) {
829 				struct tid_rdma_flow *flow =
830 					&req->flows[req->setup_head];
831 
832 				/*
833 				 * Set up s_sge as it is needed for TID
834 				 * allocation. However, if the pages have been
835 				 * walked and mapped, skip it. An earlier try
836 				 * has failed to allocate the TID entries.
837 				 */
838 				if (!flow->npagesets) {
839 					qp->s_sge.sge = wqe->sg_list[0];
840 					qp->s_sge.sg_list = wqe->sg_list + 1;
841 					qp->s_sge.num_sge = wqe->wr.num_sge;
842 					qp->s_sge.total_len = wqe->length;
843 					qp->s_len = wqe->length;
844 					req->isge = 0;
845 					req->clear_tail = req->setup_head;
846 					req->flow_idx = req->setup_head;
847 					req->state = TID_REQUEST_ACTIVE;
848 				}
849 			} else if (delta == 0) {
850 				/* Re-send a request */
851 				req->cur_seg = 0;
852 				req->comp_seg = 0;
853 				req->ack_pending = 0;
854 				req->flow_idx = req->clear_tail;
855 				req->state = TID_REQUEST_RESEND;
856 			}
857 			req->s_next_psn = qp->s_psn;
858 			/* Read one segment at a time */
859 			len = min_t(u32, req->seg_len,
860 				    wqe->length - req->seg_len * req->cur_seg);
861 			delta = hfi1_build_tid_rdma_read_req(qp, wqe, ohdr,
862 							     &bth1, &bth2,
863 							     &len);
864 			if (delta <= 0) {
865 				/* Wait for TID space */
866 				goto bail;
867 			}
868 			if (newreq && !(qp->s_flags & RVT_S_UNLIMITED_CREDIT))
869 				qp->s_lsn++;
870 			hwords += delta;
871 			ss = &wpriv->ss;
872 			/* Check if this is the last segment */
873 			if (req->cur_seg >= req->total_segs &&
874 			    ++qp->s_cur == qp->s_size)
875 				qp->s_cur = 0;
876 			break;
877 
878 		case IB_WR_ATOMIC_CMP_AND_SWP:
879 		case IB_WR_ATOMIC_FETCH_AND_ADD:
880 			/*
881 			 * Don't allow more operations to be started
882 			 * than the QP limits allow.
883 			 */
884 			if (qp->s_num_rd_atomic >=
885 			    qp->s_max_rd_atomic) {
886 				qp->s_flags |= RVT_S_WAIT_RDMAR;
887 				goto bail;
888 			}
889 			qp->s_num_rd_atomic++;
890 
891 			/* FALLTHROUGH */
892 		case IB_WR_OPFN:
893 			if (newreq && !(qp->s_flags & RVT_S_UNLIMITED_CREDIT))
894 				qp->s_lsn++;
895 			if (wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
896 			    wqe->wr.opcode == IB_WR_OPFN) {
897 				qp->s_state = OP(COMPARE_SWAP);
898 				put_ib_ateth_swap(wqe->atomic_wr.swap,
899 						  &ohdr->u.atomic_eth);
900 				put_ib_ateth_compare(wqe->atomic_wr.compare_add,
901 						     &ohdr->u.atomic_eth);
902 			} else {
903 				qp->s_state = OP(FETCH_ADD);
904 				put_ib_ateth_swap(wqe->atomic_wr.compare_add,
905 						  &ohdr->u.atomic_eth);
906 				put_ib_ateth_compare(0, &ohdr->u.atomic_eth);
907 			}
908 			put_ib_ateth_vaddr(wqe->atomic_wr.remote_addr,
909 					   &ohdr->u.atomic_eth);
910 			ohdr->u.atomic_eth.rkey = cpu_to_be32(
911 				wqe->atomic_wr.rkey);
912 			hwords += sizeof(struct ib_atomic_eth) / sizeof(u32);
913 			ss = NULL;
914 			len = 0;
915 			bth2 |= IB_BTH_REQ_ACK;
916 			if (++qp->s_cur == qp->s_size)
917 				qp->s_cur = 0;
918 			break;
919 
920 		default:
921 			goto bail;
922 		}
923 		if (wqe->wr.opcode != IB_WR_TID_RDMA_READ) {
924 			qp->s_sge.sge = wqe->sg_list[0];
925 			qp->s_sge.sg_list = wqe->sg_list + 1;
926 			qp->s_sge.num_sge = wqe->wr.num_sge;
927 			qp->s_sge.total_len = wqe->length;
928 			qp->s_len = wqe->length;
929 		}
930 		if (newreq) {
931 			qp->s_tail++;
932 			if (qp->s_tail >= qp->s_size)
933 				qp->s_tail = 0;
934 		}
935 		if (wqe->wr.opcode == IB_WR_RDMA_READ ||
936 		    wqe->wr.opcode == IB_WR_TID_RDMA_WRITE)
937 			qp->s_psn = wqe->lpsn + 1;
938 		else if (wqe->wr.opcode == IB_WR_TID_RDMA_READ)
939 			qp->s_psn = req->s_next_psn;
940 		else
941 			qp->s_psn++;
942 		break;
943 
944 	case OP(RDMA_READ_RESPONSE_FIRST):
945 		/*
946 		 * qp->s_state is normally set to the opcode of the
947 		 * last packet constructed for new requests and therefore
948 		 * is never set to RDMA read response.
949 		 * RDMA_READ_RESPONSE_FIRST is used by the ACK processing
950 		 * thread to indicate a SEND needs to be restarted from an
951 		 * earlier PSN without interfering with the sending thread.
952 		 * See restart_rc().
953 		 */
954 		qp->s_len = restart_sge(&qp->s_sge, wqe, qp->s_psn, pmtu);
955 		/* FALLTHROUGH */
956 	case OP(SEND_FIRST):
957 		qp->s_state = OP(SEND_MIDDLE);
958 		/* FALLTHROUGH */
959 	case OP(SEND_MIDDLE):
960 		bth2 = mask_psn(qp->s_psn++);
961 		ss = &qp->s_sge;
962 		len = qp->s_len;
963 		if (len > pmtu) {
964 			len = pmtu;
965 			middle = HFI1_CAP_IS_KSET(SDMA_AHG);
966 			break;
967 		}
968 		if (wqe->wr.opcode == IB_WR_SEND) {
969 			qp->s_state = OP(SEND_LAST);
970 		} else if (wqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
971 			qp->s_state = OP(SEND_LAST_WITH_IMMEDIATE);
972 			/* Immediate data comes after the BTH */
973 			ohdr->u.imm_data = wqe->wr.ex.imm_data;
974 			hwords += 1;
975 		} else {
976 			qp->s_state = OP(SEND_LAST_WITH_INVALIDATE);
977 			/* invalidate data comes after the BTH */
978 			ohdr->u.ieth = cpu_to_be32(wqe->wr.ex.invalidate_rkey);
979 			hwords += 1;
980 		}
981 		if (wqe->wr.send_flags & IB_SEND_SOLICITED)
982 			bth0 |= IB_BTH_SOLICITED;
983 		bth2 |= IB_BTH_REQ_ACK;
984 		qp->s_cur++;
985 		if (qp->s_cur >= qp->s_size)
986 			qp->s_cur = 0;
987 		break;
988 
989 	case OP(RDMA_READ_RESPONSE_LAST):
990 		/*
991 		 * qp->s_state is normally set to the opcode of the
992 		 * last packet constructed for new requests and therefore
993 		 * is never set to RDMA read response.
994 		 * RDMA_READ_RESPONSE_LAST is used by the ACK processing
995 		 * thread to indicate a RDMA write needs to be restarted from
996 		 * an earlier PSN without interfering with the sending thread.
997 		 * See restart_rc().
998 		 */
999 		qp->s_len = restart_sge(&qp->s_sge, wqe, qp->s_psn, pmtu);
1000 		/* FALLTHROUGH */
1001 	case OP(RDMA_WRITE_FIRST):
1002 		qp->s_state = OP(RDMA_WRITE_MIDDLE);
1003 		/* FALLTHROUGH */
1004 	case OP(RDMA_WRITE_MIDDLE):
1005 		bth2 = mask_psn(qp->s_psn++);
1006 		ss = &qp->s_sge;
1007 		len = qp->s_len;
1008 		if (len > pmtu) {
1009 			len = pmtu;
1010 			middle = HFI1_CAP_IS_KSET(SDMA_AHG);
1011 			break;
1012 		}
1013 		if (wqe->wr.opcode == IB_WR_RDMA_WRITE) {
1014 			qp->s_state = OP(RDMA_WRITE_LAST);
1015 		} else {
1016 			qp->s_state = OP(RDMA_WRITE_LAST_WITH_IMMEDIATE);
1017 			/* Immediate data comes after the BTH */
1018 			ohdr->u.imm_data = wqe->wr.ex.imm_data;
1019 			hwords += 1;
1020 			if (wqe->wr.send_flags & IB_SEND_SOLICITED)
1021 				bth0 |= IB_BTH_SOLICITED;
1022 		}
1023 		bth2 |= IB_BTH_REQ_ACK;
1024 		qp->s_cur++;
1025 		if (qp->s_cur >= qp->s_size)
1026 			qp->s_cur = 0;
1027 		break;
1028 
1029 	case OP(RDMA_READ_RESPONSE_MIDDLE):
1030 		/*
1031 		 * qp->s_state is normally set to the opcode of the
1032 		 * last packet constructed for new requests and therefore
1033 		 * is never set to RDMA read response.
1034 		 * RDMA_READ_RESPONSE_MIDDLE is used by the ACK processing
1035 		 * thread to indicate a RDMA read needs to be restarted from
1036 		 * an earlier PSN without interfering with the sending thread.
1037 		 * See restart_rc().
1038 		 */
1039 		len = (delta_psn(qp->s_psn, wqe->psn)) * pmtu;
1040 		put_ib_reth_vaddr(
1041 			wqe->rdma_wr.remote_addr + len,
1042 			&ohdr->u.rc.reth);
1043 		ohdr->u.rc.reth.rkey =
1044 			cpu_to_be32(wqe->rdma_wr.rkey);
1045 		ohdr->u.rc.reth.length = cpu_to_be32(wqe->length - len);
1046 		qp->s_state = OP(RDMA_READ_REQUEST);
1047 		hwords += sizeof(ohdr->u.rc.reth) / sizeof(u32);
1048 		bth2 = mask_psn(qp->s_psn) | IB_BTH_REQ_ACK;
1049 		qp->s_psn = wqe->lpsn + 1;
1050 		ss = NULL;
1051 		len = 0;
1052 		qp->s_cur++;
1053 		if (qp->s_cur == qp->s_size)
1054 			qp->s_cur = 0;
1055 		break;
1056 
1057 	case TID_OP(WRITE_RESP):
1058 		/*
1059 		 * This value for s_state is used for restarting a TID RDMA
1060 		 * WRITE request. See comment in OP(RDMA_READ_RESPONSE_MIDDLE
1061 		 * for more).
1062 		 */
1063 		req = wqe_to_tid_req(wqe);
1064 		req->state = TID_REQUEST_RESEND;
1065 		rcu_read_lock();
1066 		remote = rcu_dereference(priv->tid_rdma.remote);
1067 		req->comp_seg = delta_psn(qp->s_psn, wqe->psn);
1068 		len = wqe->length - (req->comp_seg * remote->max_len);
1069 		rcu_read_unlock();
1070 
1071 		bth2 = mask_psn(qp->s_psn);
1072 		hwords += hfi1_build_tid_rdma_write_req(qp, wqe, ohdr, &bth1,
1073 							&bth2, &len);
1074 		qp->s_psn = wqe->lpsn + 1;
1075 		ss = NULL;
1076 		qp->s_state = TID_OP(WRITE_REQ);
1077 		priv->pending_tid_w_resp += delta_psn(wqe->lpsn, bth2) + 1;
1078 		priv->s_tid_cur = qp->s_cur;
1079 		if (++qp->s_cur == qp->s_size)
1080 			qp->s_cur = 0;
1081 		trace_hfi1_tid_req_make_req_write(qp, 0, wqe->wr.opcode,
1082 						  wqe->psn, wqe->lpsn, req);
1083 		break;
1084 
1085 	case TID_OP(READ_RESP):
1086 		if (wqe->wr.opcode != IB_WR_TID_RDMA_READ)
1087 			goto bail;
1088 		/* This is used to restart a TID read request */
1089 		req = wqe_to_tid_req(wqe);
1090 		wpriv = wqe->priv;
1091 		/*
1092 		 * Back down. The field qp->s_psn has been set to the psn with
1093 		 * which the request should be restart. It's OK to use division
1094 		 * as this is on the retry path.
1095 		 */
1096 		req->cur_seg = delta_psn(qp->s_psn, wqe->psn) / priv->pkts_ps;
1097 
1098 		/*
1099 		 * The following function need to be redefined to return the
1100 		 * status to make sure that we find the flow. At the same
1101 		 * time, we can use the req->state change to check if the
1102 		 * call succeeds or not.
1103 		 */
1104 		req->state = TID_REQUEST_RESEND;
1105 		hfi1_tid_rdma_restart_req(qp, wqe, &bth2);
1106 		if (req->state != TID_REQUEST_ACTIVE) {
1107 			/*
1108 			 * Failed to find the flow. Release all allocated tid
1109 			 * resources.
1110 			 */
1111 			hfi1_kern_exp_rcv_clear_all(req);
1112 			hfi1_kern_clear_hw_flow(priv->rcd, qp);
1113 
1114 			hfi1_trdma_send_complete(qp, wqe, IB_WC_LOC_QP_OP_ERR);
1115 			goto bail;
1116 		}
1117 		req->state = TID_REQUEST_RESEND;
1118 		len = min_t(u32, req->seg_len,
1119 			    wqe->length - req->seg_len * req->cur_seg);
1120 		flow = &req->flows[req->flow_idx];
1121 		len -= flow->sent;
1122 		req->s_next_psn = flow->flow_state.ib_lpsn + 1;
1123 		delta = hfi1_build_tid_rdma_read_packet(wqe, ohdr, &bth1,
1124 							&bth2, &len);
1125 		if (delta <= 0) {
1126 			/* Wait for TID space */
1127 			goto bail;
1128 		}
1129 		hwords += delta;
1130 		ss = &wpriv->ss;
1131 		/* Check if this is the last segment */
1132 		if (req->cur_seg >= req->total_segs &&
1133 		    ++qp->s_cur == qp->s_size)
1134 			qp->s_cur = 0;
1135 		qp->s_psn = req->s_next_psn;
1136 		trace_hfi1_tid_req_make_req_read(qp, 0, wqe->wr.opcode,
1137 						 wqe->psn, wqe->lpsn, req);
1138 		break;
1139 	case TID_OP(READ_REQ):
1140 		req = wqe_to_tid_req(wqe);
1141 		delta = cmp_psn(qp->s_psn, wqe->psn);
1142 		/*
1143 		 * If the current WR is not TID RDMA READ, or this is the start
1144 		 * of a new request, we need to change the qp->s_state so that
1145 		 * the request can be set up properly.
1146 		 */
1147 		if (wqe->wr.opcode != IB_WR_TID_RDMA_READ || delta == 0 ||
1148 		    qp->s_cur == qp->s_tail) {
1149 			qp->s_state = OP(RDMA_READ_REQUEST);
1150 			if (delta == 0 || qp->s_cur == qp->s_tail)
1151 				goto check_s_state;
1152 			else
1153 				goto bail;
1154 		}
1155 
1156 		/* Rate limiting */
1157 		if (qp->s_num_rd_atomic >= qp->s_max_rd_atomic) {
1158 			qp->s_flags |= RVT_S_WAIT_RDMAR;
1159 			goto bail;
1160 		}
1161 
1162 		wpriv = wqe->priv;
1163 		/* Read one segment at a time */
1164 		len = min_t(u32, req->seg_len,
1165 			    wqe->length - req->seg_len * req->cur_seg);
1166 		delta = hfi1_build_tid_rdma_read_req(qp, wqe, ohdr, &bth1,
1167 						     &bth2, &len);
1168 		if (delta <= 0) {
1169 			/* Wait for TID space */
1170 			goto bail;
1171 		}
1172 		hwords += delta;
1173 		ss = &wpriv->ss;
1174 		/* Check if this is the last segment */
1175 		if (req->cur_seg >= req->total_segs &&
1176 		    ++qp->s_cur == qp->s_size)
1177 			qp->s_cur = 0;
1178 		qp->s_psn = req->s_next_psn;
1179 		trace_hfi1_tid_req_make_req_read(qp, 0, wqe->wr.opcode,
1180 						 wqe->psn, wqe->lpsn, req);
1181 		break;
1182 	}
1183 	qp->s_sending_hpsn = bth2;
1184 	delta = delta_psn(bth2, wqe->psn);
1185 	if (delta && delta % HFI1_PSN_CREDIT == 0 &&
1186 	    wqe->wr.opcode != IB_WR_TID_RDMA_WRITE)
1187 		bth2 |= IB_BTH_REQ_ACK;
1188 	if (qp->s_flags & RVT_S_SEND_ONE) {
1189 		qp->s_flags &= ~RVT_S_SEND_ONE;
1190 		qp->s_flags |= RVT_S_WAIT_ACK;
1191 		bth2 |= IB_BTH_REQ_ACK;
1192 	}
1193 	qp->s_len -= len;
1194 	ps->s_txreq->hdr_dwords = hwords;
1195 	ps->s_txreq->sde = priv->s_sde;
1196 	ps->s_txreq->ss = ss;
1197 	ps->s_txreq->s_cur_size = len;
1198 	hfi1_make_ruc_header(
1199 		qp,
1200 		ohdr,
1201 		bth0 | (qp->s_state << 24),
1202 		bth1,
1203 		bth2,
1204 		middle,
1205 		ps);
1206 	return 1;
1207 
1208 done_free_tx:
1209 	hfi1_put_txreq(ps->s_txreq);
1210 	ps->s_txreq = NULL;
1211 	return 1;
1212 
1213 bail:
1214 	hfi1_put_txreq(ps->s_txreq);
1215 
1216 bail_no_tx:
1217 	ps->s_txreq = NULL;
1218 	qp->s_flags &= ~RVT_S_BUSY;
1219 	/*
1220 	 * If we didn't get a txreq, the QP will be woken up later to try
1221 	 * again. Set the flags to indicate which work item to wake
1222 	 * up.
1223 	 */
1224 	iowait_set_flag(&priv->s_iowait, IOWAIT_PENDING_IB);
1225 	return 0;
1226 }
1227 
1228 static inline void hfi1_make_bth_aeth(struct rvt_qp *qp,
1229 				      struct ib_other_headers *ohdr,
1230 				      u32 bth0, u32 bth1)
1231 {
1232 	if (qp->r_nak_state)
1233 		ohdr->u.aeth = cpu_to_be32((qp->r_msn & IB_MSN_MASK) |
1234 					    (qp->r_nak_state <<
1235 					     IB_AETH_CREDIT_SHIFT));
1236 	else
1237 		ohdr->u.aeth = rvt_compute_aeth(qp);
1238 
1239 	ohdr->bth[0] = cpu_to_be32(bth0);
1240 	ohdr->bth[1] = cpu_to_be32(bth1 | qp->remote_qpn);
1241 	ohdr->bth[2] = cpu_to_be32(mask_psn(qp->r_ack_psn));
1242 }
1243 
1244 static inline void hfi1_queue_rc_ack(struct hfi1_packet *packet, bool is_fecn)
1245 {
1246 	struct rvt_qp *qp = packet->qp;
1247 	struct hfi1_ibport *ibp;
1248 	unsigned long flags;
1249 
1250 	spin_lock_irqsave(&qp->s_lock, flags);
1251 	if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK))
1252 		goto unlock;
1253 	ibp = rcd_to_iport(packet->rcd);
1254 	this_cpu_inc(*ibp->rvp.rc_qacks);
1255 	qp->s_flags |= RVT_S_ACK_PENDING | RVT_S_RESP_PENDING;
1256 	qp->s_nak_state = qp->r_nak_state;
1257 	qp->s_ack_psn = qp->r_ack_psn;
1258 	if (is_fecn)
1259 		qp->s_flags |= RVT_S_ECN;
1260 
1261 	/* Schedule the send tasklet. */
1262 	hfi1_schedule_send(qp);
1263 unlock:
1264 	spin_unlock_irqrestore(&qp->s_lock, flags);
1265 }
1266 
1267 static inline void hfi1_make_rc_ack_9B(struct hfi1_packet *packet,
1268 				       struct hfi1_opa_header *opa_hdr,
1269 				       u8 sc5, bool is_fecn,
1270 				       u64 *pbc_flags, u32 *hwords,
1271 				       u32 *nwords)
1272 {
1273 	struct rvt_qp *qp = packet->qp;
1274 	struct hfi1_ibport *ibp = rcd_to_iport(packet->rcd);
1275 	struct hfi1_pportdata *ppd = ppd_from_ibp(ibp);
1276 	struct ib_header *hdr = &opa_hdr->ibh;
1277 	struct ib_other_headers *ohdr;
1278 	u16 lrh0 = HFI1_LRH_BTH;
1279 	u16 pkey;
1280 	u32 bth0, bth1;
1281 
1282 	opa_hdr->hdr_type = HFI1_PKT_TYPE_9B;
1283 	ohdr = &hdr->u.oth;
1284 	/* header size in 32-bit words LRH+BTH+AETH = (8+12+4)/4 */
1285 	*hwords = 6;
1286 
1287 	if (unlikely(rdma_ah_get_ah_flags(&qp->remote_ah_attr) & IB_AH_GRH)) {
1288 		*hwords += hfi1_make_grh(ibp, &hdr->u.l.grh,
1289 					 rdma_ah_read_grh(&qp->remote_ah_attr),
1290 					 *hwords - 2, SIZE_OF_CRC);
1291 		ohdr = &hdr->u.l.oth;
1292 		lrh0 = HFI1_LRH_GRH;
1293 	}
1294 	/* set PBC_DC_INFO bit (aka SC[4]) in pbc_flags */
1295 	*pbc_flags |= ((!!(sc5 & 0x10)) << PBC_DC_INFO_SHIFT);
1296 
1297 	/* read pkey_index w/o lock (its atomic) */
1298 	pkey = hfi1_get_pkey(ibp, qp->s_pkey_index);
1299 
1300 	lrh0 |= (sc5 & IB_SC_MASK) << IB_SC_SHIFT |
1301 		(rdma_ah_get_sl(&qp->remote_ah_attr) & IB_SL_MASK) <<
1302 			IB_SL_SHIFT;
1303 
1304 	hfi1_make_ib_hdr(hdr, lrh0, *hwords + SIZE_OF_CRC,
1305 			 opa_get_lid(rdma_ah_get_dlid(&qp->remote_ah_attr), 9B),
1306 			 ppd->lid | rdma_ah_get_path_bits(&qp->remote_ah_attr));
1307 
1308 	bth0 = pkey | (OP(ACKNOWLEDGE) << 24);
1309 	if (qp->s_mig_state == IB_MIG_MIGRATED)
1310 		bth0 |= IB_BTH_MIG_REQ;
1311 	bth1 = (!!is_fecn) << IB_BECN_SHIFT;
1312 	/*
1313 	 * Inline ACKs go out without the use of the Verbs send engine, so
1314 	 * we need to set the STL Verbs Extended bit here
1315 	 */
1316 	bth1 |= HFI1_CAP_IS_KSET(OPFN) << IB_BTHE_E_SHIFT;
1317 	hfi1_make_bth_aeth(qp, ohdr, bth0, bth1);
1318 }
1319 
1320 static inline void hfi1_make_rc_ack_16B(struct hfi1_packet *packet,
1321 					struct hfi1_opa_header *opa_hdr,
1322 					u8 sc5, bool is_fecn,
1323 					u64 *pbc_flags, u32 *hwords,
1324 					u32 *nwords)
1325 {
1326 	struct rvt_qp *qp = packet->qp;
1327 	struct hfi1_ibport *ibp = rcd_to_iport(packet->rcd);
1328 	struct hfi1_pportdata *ppd = ppd_from_ibp(ibp);
1329 	struct hfi1_16b_header *hdr = &opa_hdr->opah;
1330 	struct ib_other_headers *ohdr;
1331 	u32 bth0, bth1 = 0;
1332 	u16 len, pkey;
1333 	bool becn = is_fecn;
1334 	u8 l4 = OPA_16B_L4_IB_LOCAL;
1335 	u8 extra_bytes;
1336 
1337 	opa_hdr->hdr_type = HFI1_PKT_TYPE_16B;
1338 	ohdr = &hdr->u.oth;
1339 	/* header size in 32-bit words 16B LRH+BTH+AETH = (16+12+4)/4 */
1340 	*hwords = 8;
1341 	extra_bytes = hfi1_get_16b_padding(*hwords << 2, 0);
1342 	*nwords = SIZE_OF_CRC + ((extra_bytes + SIZE_OF_LT) >> 2);
1343 
1344 	if (unlikely(rdma_ah_get_ah_flags(&qp->remote_ah_attr) & IB_AH_GRH) &&
1345 	    hfi1_check_mcast(rdma_ah_get_dlid(&qp->remote_ah_attr))) {
1346 		*hwords += hfi1_make_grh(ibp, &hdr->u.l.grh,
1347 					 rdma_ah_read_grh(&qp->remote_ah_attr),
1348 					 *hwords - 4, *nwords);
1349 		ohdr = &hdr->u.l.oth;
1350 		l4 = OPA_16B_L4_IB_GLOBAL;
1351 	}
1352 	*pbc_flags |= PBC_PACKET_BYPASS | PBC_INSERT_BYPASS_ICRC;
1353 
1354 	/* read pkey_index w/o lock (its atomic) */
1355 	pkey = hfi1_get_pkey(ibp, qp->s_pkey_index);
1356 
1357 	/* Convert dwords to flits */
1358 	len = (*hwords + *nwords) >> 1;
1359 
1360 	hfi1_make_16b_hdr(hdr, ppd->lid |
1361 			  (rdma_ah_get_path_bits(&qp->remote_ah_attr) &
1362 			  ((1 << ppd->lmc) - 1)),
1363 			  opa_get_lid(rdma_ah_get_dlid(&qp->remote_ah_attr),
1364 				      16B), len, pkey, becn, 0, l4, sc5);
1365 
1366 	bth0 = pkey | (OP(ACKNOWLEDGE) << 24);
1367 	bth0 |= extra_bytes << 20;
1368 	if (qp->s_mig_state == IB_MIG_MIGRATED)
1369 		bth1 = OPA_BTH_MIG_REQ;
1370 	hfi1_make_bth_aeth(qp, ohdr, bth0, bth1);
1371 }
1372 
1373 typedef void (*hfi1_make_rc_ack)(struct hfi1_packet *packet,
1374 				 struct hfi1_opa_header *opa_hdr,
1375 				 u8 sc5, bool is_fecn,
1376 				 u64 *pbc_flags, u32 *hwords,
1377 				 u32 *nwords);
1378 
1379 /* We support only two types - 9B and 16B for now */
1380 static const hfi1_make_rc_ack hfi1_make_rc_ack_tbl[2] = {
1381 	[HFI1_PKT_TYPE_9B] = &hfi1_make_rc_ack_9B,
1382 	[HFI1_PKT_TYPE_16B] = &hfi1_make_rc_ack_16B
1383 };
1384 
1385 /**
1386  * hfi1_send_rc_ack - Construct an ACK packet and send it
1387  * @qp: a pointer to the QP
1388  *
1389  * This is called from hfi1_rc_rcv() and handle_receive_interrupt().
1390  * Note that RDMA reads and atomics are handled in the
1391  * send side QP state and send engine.
1392  */
1393 void hfi1_send_rc_ack(struct hfi1_packet *packet, bool is_fecn)
1394 {
1395 	struct hfi1_ctxtdata *rcd = packet->rcd;
1396 	struct rvt_qp *qp = packet->qp;
1397 	struct hfi1_ibport *ibp = rcd_to_iport(rcd);
1398 	struct hfi1_qp_priv *priv = qp->priv;
1399 	struct hfi1_pportdata *ppd = ppd_from_ibp(ibp);
1400 	u8 sc5 = ibp->sl_to_sc[rdma_ah_get_sl(&qp->remote_ah_attr)];
1401 	u64 pbc, pbc_flags = 0;
1402 	u32 hwords = 0;
1403 	u32 nwords = 0;
1404 	u32 plen;
1405 	struct pio_buf *pbuf;
1406 	struct hfi1_opa_header opa_hdr;
1407 
1408 	/* clear the defer count */
1409 	qp->r_adefered = 0;
1410 
1411 	/* Don't send ACK or NAK if a RDMA read or atomic is pending. */
1412 	if (qp->s_flags & RVT_S_RESP_PENDING) {
1413 		hfi1_queue_rc_ack(packet, is_fecn);
1414 		return;
1415 	}
1416 
1417 	/* Ensure s_rdma_ack_cnt changes are committed */
1418 	if (qp->s_rdma_ack_cnt) {
1419 		hfi1_queue_rc_ack(packet, is_fecn);
1420 		return;
1421 	}
1422 
1423 	/* Don't try to send ACKs if the link isn't ACTIVE */
1424 	if (driver_lstate(ppd) != IB_PORT_ACTIVE)
1425 		return;
1426 
1427 	/* Make the appropriate header */
1428 	hfi1_make_rc_ack_tbl[priv->hdr_type](packet, &opa_hdr, sc5, is_fecn,
1429 					     &pbc_flags, &hwords, &nwords);
1430 
1431 	plen = 2 /* PBC */ + hwords + nwords;
1432 	pbc = create_pbc(ppd, pbc_flags, qp->srate_mbps,
1433 			 sc_to_vlt(ppd->dd, sc5), plen);
1434 	pbuf = sc_buffer_alloc(rcd->sc, plen, NULL, NULL);
1435 	if (IS_ERR_OR_NULL(pbuf)) {
1436 		/*
1437 		 * We have no room to send at the moment.  Pass
1438 		 * responsibility for sending the ACK to the send engine
1439 		 * so that when enough buffer space becomes available,
1440 		 * the ACK is sent ahead of other outgoing packets.
1441 		 */
1442 		hfi1_queue_rc_ack(packet, is_fecn);
1443 		return;
1444 	}
1445 	trace_ack_output_ibhdr(dd_from_ibdev(qp->ibqp.device),
1446 			       &opa_hdr, ib_is_sc5(sc5));
1447 
1448 	/* write the pbc and data */
1449 	ppd->dd->pio_inline_send(ppd->dd, pbuf, pbc,
1450 				 (priv->hdr_type == HFI1_PKT_TYPE_9B ?
1451 				 (void *)&opa_hdr.ibh :
1452 				 (void *)&opa_hdr.opah), hwords);
1453 	return;
1454 }
1455 
1456 /**
1457  * update_num_rd_atomic - update the qp->s_num_rd_atomic
1458  * @qp: the QP
1459  * @psn: the packet sequence number to restart at
1460  * @wqe: the wqe
1461  *
1462  * This is called from reset_psn() to update qp->s_num_rd_atomic
1463  * for the current wqe.
1464  * Called at interrupt level with the QP s_lock held.
1465  */
1466 static void update_num_rd_atomic(struct rvt_qp *qp, u32 psn,
1467 				 struct rvt_swqe *wqe)
1468 {
1469 	u32 opcode = wqe->wr.opcode;
1470 
1471 	if (opcode == IB_WR_RDMA_READ ||
1472 	    opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1473 	    opcode == IB_WR_ATOMIC_FETCH_AND_ADD) {
1474 		qp->s_num_rd_atomic++;
1475 	} else if (opcode == IB_WR_TID_RDMA_READ) {
1476 		struct tid_rdma_request *req = wqe_to_tid_req(wqe);
1477 		struct hfi1_qp_priv *priv = qp->priv;
1478 
1479 		if (cmp_psn(psn, wqe->lpsn) <= 0) {
1480 			u32 cur_seg;
1481 
1482 			cur_seg = (psn - wqe->psn) / priv->pkts_ps;
1483 			req->ack_pending = cur_seg - req->comp_seg;
1484 			priv->pending_tid_r_segs += req->ack_pending;
1485 			qp->s_num_rd_atomic += req->ack_pending;
1486 		} else {
1487 			priv->pending_tid_r_segs += req->total_segs;
1488 			qp->s_num_rd_atomic += req->total_segs;
1489 		}
1490 	}
1491 }
1492 
1493 /**
1494  * reset_psn - reset the QP state to send starting from PSN
1495  * @qp: the QP
1496  * @psn: the packet sequence number to restart at
1497  *
1498  * This is called from hfi1_rc_rcv() to process an incoming RC ACK
1499  * for the given QP.
1500  * Called at interrupt level with the QP s_lock held.
1501  */
1502 static void reset_psn(struct rvt_qp *qp, u32 psn)
1503 {
1504 	u32 n = qp->s_acked;
1505 	struct rvt_swqe *wqe = rvt_get_swqe_ptr(qp, n);
1506 	u32 opcode;
1507 	struct hfi1_qp_priv *priv = qp->priv;
1508 
1509 	lockdep_assert_held(&qp->s_lock);
1510 	qp->s_cur = n;
1511 	priv->pending_tid_r_segs = 0;
1512 	priv->pending_tid_w_resp = 0;
1513 	qp->s_num_rd_atomic = 0;
1514 
1515 	/*
1516 	 * If we are starting the request from the beginning,
1517 	 * let the normal send code handle initialization.
1518 	 */
1519 	if (cmp_psn(psn, wqe->psn) <= 0) {
1520 		qp->s_state = OP(SEND_LAST);
1521 		goto done;
1522 	}
1523 	update_num_rd_atomic(qp, psn, wqe);
1524 
1525 	/* Find the work request opcode corresponding to the given PSN. */
1526 	for (;;) {
1527 		int diff;
1528 
1529 		if (++n == qp->s_size)
1530 			n = 0;
1531 		if (n == qp->s_tail)
1532 			break;
1533 		wqe = rvt_get_swqe_ptr(qp, n);
1534 		diff = cmp_psn(psn, wqe->psn);
1535 		if (diff < 0) {
1536 			/* Point wqe back to the previous one*/
1537 			wqe = rvt_get_swqe_ptr(qp, qp->s_cur);
1538 			break;
1539 		}
1540 		qp->s_cur = n;
1541 		/*
1542 		 * If we are starting the request from the beginning,
1543 		 * let the normal send code handle initialization.
1544 		 */
1545 		if (diff == 0) {
1546 			qp->s_state = OP(SEND_LAST);
1547 			goto done;
1548 		}
1549 
1550 		update_num_rd_atomic(qp, psn, wqe);
1551 	}
1552 	opcode = wqe->wr.opcode;
1553 
1554 	/*
1555 	 * Set the state to restart in the middle of a request.
1556 	 * Don't change the s_sge, s_cur_sge, or s_cur_size.
1557 	 * See hfi1_make_rc_req().
1558 	 */
1559 	switch (opcode) {
1560 	case IB_WR_SEND:
1561 	case IB_WR_SEND_WITH_IMM:
1562 		qp->s_state = OP(RDMA_READ_RESPONSE_FIRST);
1563 		break;
1564 
1565 	case IB_WR_RDMA_WRITE:
1566 	case IB_WR_RDMA_WRITE_WITH_IMM:
1567 		qp->s_state = OP(RDMA_READ_RESPONSE_LAST);
1568 		break;
1569 
1570 	case IB_WR_TID_RDMA_WRITE:
1571 		qp->s_state = TID_OP(WRITE_RESP);
1572 		break;
1573 
1574 	case IB_WR_RDMA_READ:
1575 		qp->s_state = OP(RDMA_READ_RESPONSE_MIDDLE);
1576 		break;
1577 
1578 	case IB_WR_TID_RDMA_READ:
1579 		qp->s_state = TID_OP(READ_RESP);
1580 		break;
1581 
1582 	default:
1583 		/*
1584 		 * This case shouldn't happen since its only
1585 		 * one PSN per req.
1586 		 */
1587 		qp->s_state = OP(SEND_LAST);
1588 	}
1589 done:
1590 	priv->s_flags &= ~HFI1_S_TID_WAIT_INTERLCK;
1591 	qp->s_psn = psn;
1592 	/*
1593 	 * Set RVT_S_WAIT_PSN as rc_complete() may start the timer
1594 	 * asynchronously before the send engine can get scheduled.
1595 	 * Doing it in hfi1_make_rc_req() is too late.
1596 	 */
1597 	if ((cmp_psn(qp->s_psn, qp->s_sending_hpsn) <= 0) &&
1598 	    (cmp_psn(qp->s_sending_psn, qp->s_sending_hpsn) <= 0))
1599 		qp->s_flags |= RVT_S_WAIT_PSN;
1600 	qp->s_flags &= ~HFI1_S_AHG_VALID;
1601 	trace_hfi1_sender_reset_psn(qp);
1602 }
1603 
1604 /*
1605  * Back up requester to resend the last un-ACKed request.
1606  * The QP r_lock and s_lock should be held and interrupts disabled.
1607  */
1608 void hfi1_restart_rc(struct rvt_qp *qp, u32 psn, int wait)
1609 {
1610 	struct hfi1_qp_priv *priv = qp->priv;
1611 	struct rvt_swqe *wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1612 	struct hfi1_ibport *ibp;
1613 
1614 	lockdep_assert_held(&qp->r_lock);
1615 	lockdep_assert_held(&qp->s_lock);
1616 	trace_hfi1_sender_restart_rc(qp);
1617 	if (qp->s_retry == 0) {
1618 		if (qp->s_mig_state == IB_MIG_ARMED) {
1619 			hfi1_migrate_qp(qp);
1620 			qp->s_retry = qp->s_retry_cnt;
1621 		} else if (qp->s_last == qp->s_acked) {
1622 			/*
1623 			 * We need special handling for the OPFN request WQEs as
1624 			 * they are not allowed to generate real user errors
1625 			 */
1626 			if (wqe->wr.opcode == IB_WR_OPFN) {
1627 				struct hfi1_ibport *ibp =
1628 					to_iport(qp->ibqp.device, qp->port_num);
1629 				/*
1630 				 * Call opfn_conn_reply() with capcode and
1631 				 * remaining data as 0 to close out the
1632 				 * current request
1633 				 */
1634 				opfn_conn_reply(qp, priv->opfn.curr);
1635 				wqe = do_rc_completion(qp, wqe, ibp);
1636 				qp->s_flags &= ~RVT_S_WAIT_ACK;
1637 			} else {
1638 				trace_hfi1_tid_write_sender_restart_rc(qp, 0);
1639 				if (wqe->wr.opcode == IB_WR_TID_RDMA_READ) {
1640 					struct tid_rdma_request *req;
1641 
1642 					req = wqe_to_tid_req(wqe);
1643 					hfi1_kern_exp_rcv_clear_all(req);
1644 					hfi1_kern_clear_hw_flow(priv->rcd, qp);
1645 				}
1646 
1647 				hfi1_trdma_send_complete(qp, wqe,
1648 							 IB_WC_RETRY_EXC_ERR);
1649 				rvt_error_qp(qp, IB_WC_WR_FLUSH_ERR);
1650 			}
1651 			return;
1652 		} else { /* need to handle delayed completion */
1653 			return;
1654 		}
1655 	} else {
1656 		qp->s_retry--;
1657 	}
1658 
1659 	ibp = to_iport(qp->ibqp.device, qp->port_num);
1660 	if (wqe->wr.opcode == IB_WR_RDMA_READ ||
1661 	    wqe->wr.opcode == IB_WR_TID_RDMA_READ)
1662 		ibp->rvp.n_rc_resends++;
1663 	else
1664 		ibp->rvp.n_rc_resends += delta_psn(qp->s_psn, psn);
1665 
1666 	qp->s_flags &= ~(RVT_S_WAIT_FENCE | RVT_S_WAIT_RDMAR |
1667 			 RVT_S_WAIT_SSN_CREDIT | RVT_S_WAIT_PSN |
1668 			 RVT_S_WAIT_ACK | HFI1_S_WAIT_TID_RESP);
1669 	if (wait)
1670 		qp->s_flags |= RVT_S_SEND_ONE;
1671 	reset_psn(qp, psn);
1672 }
1673 
1674 /*
1675  * Set qp->s_sending_psn to the next PSN after the given one.
1676  * This would be psn+1 except when RDMA reads or TID RDMA ops
1677  * are present.
1678  */
1679 static void reset_sending_psn(struct rvt_qp *qp, u32 psn)
1680 {
1681 	struct rvt_swqe *wqe;
1682 	u32 n = qp->s_last;
1683 
1684 	lockdep_assert_held(&qp->s_lock);
1685 	/* Find the work request corresponding to the given PSN. */
1686 	for (;;) {
1687 		wqe = rvt_get_swqe_ptr(qp, n);
1688 		if (cmp_psn(psn, wqe->lpsn) <= 0) {
1689 			if (wqe->wr.opcode == IB_WR_RDMA_READ ||
1690 			    wqe->wr.opcode == IB_WR_TID_RDMA_READ ||
1691 			    wqe->wr.opcode == IB_WR_TID_RDMA_WRITE)
1692 				qp->s_sending_psn = wqe->lpsn + 1;
1693 			else
1694 				qp->s_sending_psn = psn + 1;
1695 			break;
1696 		}
1697 		if (++n == qp->s_size)
1698 			n = 0;
1699 		if (n == qp->s_tail)
1700 			break;
1701 	}
1702 }
1703 
1704 /**
1705  * hfi1_rc_verbs_aborted - handle abort status
1706  * @qp: the QP
1707  * @opah: the opa header
1708  *
1709  * This code modifies both ACK bit in BTH[2]
1710  * and the s_flags to go into send one mode.
1711  *
1712  * This serves to throttle the send engine to only
1713  * send a single packet in the likely case the
1714  * a link has gone down.
1715  */
1716 void hfi1_rc_verbs_aborted(struct rvt_qp *qp, struct hfi1_opa_header *opah)
1717 {
1718 	struct ib_other_headers *ohdr = hfi1_get_rc_ohdr(opah);
1719 	u8 opcode = ib_bth_get_opcode(ohdr);
1720 	u32 psn;
1721 
1722 	/* ignore responses */
1723 	if ((opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
1724 	     opcode <= OP(ATOMIC_ACKNOWLEDGE)) ||
1725 	    opcode == TID_OP(READ_RESP) ||
1726 	    opcode == TID_OP(WRITE_RESP))
1727 		return;
1728 
1729 	psn = ib_bth_get_psn(ohdr) | IB_BTH_REQ_ACK;
1730 	ohdr->bth[2] = cpu_to_be32(psn);
1731 	qp->s_flags |= RVT_S_SEND_ONE;
1732 }
1733 
1734 /*
1735  * This should be called with the QP s_lock held and interrupts disabled.
1736  */
1737 void hfi1_rc_send_complete(struct rvt_qp *qp, struct hfi1_opa_header *opah)
1738 {
1739 	struct ib_other_headers *ohdr;
1740 	struct hfi1_qp_priv *priv = qp->priv;
1741 	struct rvt_swqe *wqe;
1742 	u32 opcode, head, tail;
1743 	u32 psn;
1744 	struct tid_rdma_request *req;
1745 
1746 	lockdep_assert_held(&qp->s_lock);
1747 	if (!(ib_rvt_state_ops[qp->state] & RVT_SEND_OR_FLUSH_OR_RECV_OK))
1748 		return;
1749 
1750 	ohdr = hfi1_get_rc_ohdr(opah);
1751 	opcode = ib_bth_get_opcode(ohdr);
1752 	if ((opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
1753 	     opcode <= OP(ATOMIC_ACKNOWLEDGE)) ||
1754 	    opcode == TID_OP(READ_RESP) ||
1755 	    opcode == TID_OP(WRITE_RESP)) {
1756 		WARN_ON(!qp->s_rdma_ack_cnt);
1757 		qp->s_rdma_ack_cnt--;
1758 		return;
1759 	}
1760 
1761 	psn = ib_bth_get_psn(ohdr);
1762 	/*
1763 	 * Don't attempt to reset the sending PSN for packets in the
1764 	 * KDETH PSN space since the PSN does not match anything.
1765 	 */
1766 	if (opcode != TID_OP(WRITE_DATA) &&
1767 	    opcode != TID_OP(WRITE_DATA_LAST) &&
1768 	    opcode != TID_OP(ACK) && opcode != TID_OP(RESYNC))
1769 		reset_sending_psn(qp, psn);
1770 
1771 	/* Handle TID RDMA WRITE packets differently */
1772 	if (opcode >= TID_OP(WRITE_REQ) &&
1773 	    opcode <= TID_OP(WRITE_DATA_LAST)) {
1774 		head = priv->s_tid_head;
1775 		tail = priv->s_tid_cur;
1776 		/*
1777 		 * s_tid_cur is set to s_tid_head in the case, where
1778 		 * a new TID RDMA request is being started and all
1779 		 * previous ones have been completed.
1780 		 * Therefore, we need to do a secondary check in order
1781 		 * to properly determine whether we should start the
1782 		 * RC timer.
1783 		 */
1784 		wqe = rvt_get_swqe_ptr(qp, tail);
1785 		req = wqe_to_tid_req(wqe);
1786 		if (head == tail && req->comp_seg < req->total_segs) {
1787 			if (tail == 0)
1788 				tail = qp->s_size - 1;
1789 			else
1790 				tail -= 1;
1791 		}
1792 	} else {
1793 		head = qp->s_tail;
1794 		tail = qp->s_acked;
1795 	}
1796 
1797 	/*
1798 	 * Start timer after a packet requesting an ACK has been sent and
1799 	 * there are still requests that haven't been acked.
1800 	 */
1801 	if ((psn & IB_BTH_REQ_ACK) && tail != head &&
1802 	    opcode != TID_OP(WRITE_DATA) && opcode != TID_OP(WRITE_DATA_LAST) &&
1803 	    opcode != TID_OP(RESYNC) &&
1804 	    !(qp->s_flags &
1805 	      (RVT_S_TIMER | RVT_S_WAIT_RNR | RVT_S_WAIT_PSN)) &&
1806 	    (ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK)) {
1807 		if (opcode == TID_OP(READ_REQ))
1808 			rvt_add_retry_timer_ext(qp, priv->timeout_shift);
1809 		else
1810 			rvt_add_retry_timer(qp);
1811 	}
1812 
1813 	/* Start TID RDMA ACK timer */
1814 	if ((opcode == TID_OP(WRITE_DATA) ||
1815 	     opcode == TID_OP(WRITE_DATA_LAST) ||
1816 	     opcode == TID_OP(RESYNC)) &&
1817 	    (psn & IB_BTH_REQ_ACK) &&
1818 	    !(priv->s_flags & HFI1_S_TID_RETRY_TIMER) &&
1819 	    (ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK)) {
1820 		/*
1821 		 * The TID RDMA ACK packet could be received before this
1822 		 * function is called. Therefore, add the timer only if TID
1823 		 * RDMA ACK packets are actually pending.
1824 		 */
1825 		wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1826 		req = wqe_to_tid_req(wqe);
1827 		if (wqe->wr.opcode == IB_WR_TID_RDMA_WRITE &&
1828 		    req->ack_seg < req->cur_seg)
1829 			hfi1_add_tid_retry_timer(qp);
1830 	}
1831 
1832 	while (qp->s_last != qp->s_acked) {
1833 		wqe = rvt_get_swqe_ptr(qp, qp->s_last);
1834 		if (cmp_psn(wqe->lpsn, qp->s_sending_psn) >= 0 &&
1835 		    cmp_psn(qp->s_sending_psn, qp->s_sending_hpsn) <= 0)
1836 			break;
1837 		trdma_clean_swqe(qp, wqe);
1838 		trace_hfi1_qp_send_completion(qp, wqe, qp->s_last);
1839 		rvt_qp_complete_swqe(qp,
1840 				     wqe,
1841 				     ib_hfi1_wc_opcode[wqe->wr.opcode],
1842 				     IB_WC_SUCCESS);
1843 	}
1844 	/*
1845 	 * If we were waiting for sends to complete before re-sending,
1846 	 * and they are now complete, restart sending.
1847 	 */
1848 	trace_hfi1_sendcomplete(qp, psn);
1849 	if (qp->s_flags & RVT_S_WAIT_PSN &&
1850 	    cmp_psn(qp->s_sending_psn, qp->s_sending_hpsn) > 0) {
1851 		qp->s_flags &= ~RVT_S_WAIT_PSN;
1852 		qp->s_sending_psn = qp->s_psn;
1853 		qp->s_sending_hpsn = qp->s_psn - 1;
1854 		hfi1_schedule_send(qp);
1855 	}
1856 }
1857 
1858 static inline void update_last_psn(struct rvt_qp *qp, u32 psn)
1859 {
1860 	qp->s_last_psn = psn;
1861 }
1862 
1863 /*
1864  * Generate a SWQE completion.
1865  * This is similar to hfi1_send_complete but has to check to be sure
1866  * that the SGEs are not being referenced if the SWQE is being resent.
1867  */
1868 struct rvt_swqe *do_rc_completion(struct rvt_qp *qp,
1869 				  struct rvt_swqe *wqe,
1870 				  struct hfi1_ibport *ibp)
1871 {
1872 	struct hfi1_qp_priv *priv = qp->priv;
1873 
1874 	lockdep_assert_held(&qp->s_lock);
1875 	/*
1876 	 * Don't decrement refcount and don't generate a
1877 	 * completion if the SWQE is being resent until the send
1878 	 * is finished.
1879 	 */
1880 	trace_hfi1_rc_completion(qp, wqe->lpsn);
1881 	if (cmp_psn(wqe->lpsn, qp->s_sending_psn) < 0 ||
1882 	    cmp_psn(qp->s_sending_psn, qp->s_sending_hpsn) > 0) {
1883 		trdma_clean_swqe(qp, wqe);
1884 		trace_hfi1_qp_send_completion(qp, wqe, qp->s_last);
1885 		rvt_qp_complete_swqe(qp,
1886 				     wqe,
1887 				     ib_hfi1_wc_opcode[wqe->wr.opcode],
1888 				     IB_WC_SUCCESS);
1889 	} else {
1890 		struct hfi1_pportdata *ppd = ppd_from_ibp(ibp);
1891 
1892 		this_cpu_inc(*ibp->rvp.rc_delayed_comp);
1893 		/*
1894 		 * If send progress not running attempt to progress
1895 		 * SDMA queue.
1896 		 */
1897 		if (ppd->dd->flags & HFI1_HAS_SEND_DMA) {
1898 			struct sdma_engine *engine;
1899 			u8 sl = rdma_ah_get_sl(&qp->remote_ah_attr);
1900 			u8 sc5;
1901 
1902 			/* For now use sc to find engine */
1903 			sc5 = ibp->sl_to_sc[sl];
1904 			engine = qp_to_sdma_engine(qp, sc5);
1905 			sdma_engine_progress_schedule(engine);
1906 		}
1907 	}
1908 
1909 	qp->s_retry = qp->s_retry_cnt;
1910 	/*
1911 	 * Don't update the last PSN if the request being completed is
1912 	 * a TID RDMA WRITE request.
1913 	 * Completion of the TID RDMA WRITE requests are done by the
1914 	 * TID RDMA ACKs and as such could be for a request that has
1915 	 * already been ACKed as far as the IB state machine is
1916 	 * concerned.
1917 	 */
1918 	if (wqe->wr.opcode != IB_WR_TID_RDMA_WRITE)
1919 		update_last_psn(qp, wqe->lpsn);
1920 
1921 	/*
1922 	 * If we are completing a request which is in the process of
1923 	 * being resent, we can stop re-sending it since we know the
1924 	 * responder has already seen it.
1925 	 */
1926 	if (qp->s_acked == qp->s_cur) {
1927 		if (++qp->s_cur >= qp->s_size)
1928 			qp->s_cur = 0;
1929 		qp->s_acked = qp->s_cur;
1930 		wqe = rvt_get_swqe_ptr(qp, qp->s_cur);
1931 		if (qp->s_acked != qp->s_tail) {
1932 			qp->s_state = OP(SEND_LAST);
1933 			qp->s_psn = wqe->psn;
1934 		}
1935 	} else {
1936 		if (++qp->s_acked >= qp->s_size)
1937 			qp->s_acked = 0;
1938 		if (qp->state == IB_QPS_SQD && qp->s_acked == qp->s_cur)
1939 			qp->s_draining = 0;
1940 		wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1941 	}
1942 	if (priv->s_flags & HFI1_S_TID_WAIT_INTERLCK) {
1943 		priv->s_flags &= ~HFI1_S_TID_WAIT_INTERLCK;
1944 		hfi1_schedule_send(qp);
1945 	}
1946 	return wqe;
1947 }
1948 
1949 static void set_restart_qp(struct rvt_qp *qp, struct hfi1_ctxtdata *rcd)
1950 {
1951 	/* Retry this request. */
1952 	if (!(qp->r_flags & RVT_R_RDMAR_SEQ)) {
1953 		qp->r_flags |= RVT_R_RDMAR_SEQ;
1954 		hfi1_restart_rc(qp, qp->s_last_psn + 1, 0);
1955 		if (list_empty(&qp->rspwait)) {
1956 			qp->r_flags |= RVT_R_RSP_SEND;
1957 			rvt_get_qp(qp);
1958 			list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
1959 		}
1960 	}
1961 }
1962 
1963 /**
1964  * update_qp_retry_state - Update qp retry state.
1965  * @qp: the QP
1966  * @psn: the packet sequence number of the TID RDMA WRITE RESP.
1967  * @spsn:  The start psn for the given TID RDMA WRITE swqe.
1968  * @lpsn:  The last psn for the given TID RDMA WRITE swqe.
1969  *
1970  * This function is called to update the qp retry state upon
1971  * receiving a TID WRITE RESP after the qp is scheduled to retry
1972  * a request.
1973  */
1974 static void update_qp_retry_state(struct rvt_qp *qp, u32 psn, u32 spsn,
1975 				  u32 lpsn)
1976 {
1977 	struct hfi1_qp_priv *qpriv = qp->priv;
1978 
1979 	qp->s_psn = psn + 1;
1980 	/*
1981 	 * If this is the first TID RDMA WRITE RESP packet for the current
1982 	 * request, change the s_state so that the retry will be processed
1983 	 * correctly. Similarly, if this is the last TID RDMA WRITE RESP
1984 	 * packet, change the s_state and advance the s_cur.
1985 	 */
1986 	if (cmp_psn(psn, lpsn) >= 0) {
1987 		qp->s_cur = qpriv->s_tid_cur + 1;
1988 		if (qp->s_cur >= qp->s_size)
1989 			qp->s_cur = 0;
1990 		qp->s_state = TID_OP(WRITE_REQ);
1991 	} else  if (!cmp_psn(psn, spsn)) {
1992 		qp->s_cur = qpriv->s_tid_cur;
1993 		qp->s_state = TID_OP(WRITE_RESP);
1994 	}
1995 }
1996 
1997 /**
1998  * do_rc_ack - process an incoming RC ACK
1999  * @qp: the QP the ACK came in on
2000  * @psn: the packet sequence number of the ACK
2001  * @opcode: the opcode of the request that resulted in the ACK
2002  *
2003  * This is called from rc_rcv_resp() to process an incoming RC ACK
2004  * for the given QP.
2005  * May be called at interrupt level, with the QP s_lock held.
2006  * Returns 1 if OK, 0 if current operation should be aborted (NAK).
2007  */
2008 int do_rc_ack(struct rvt_qp *qp, u32 aeth, u32 psn, int opcode,
2009 	      u64 val, struct hfi1_ctxtdata *rcd)
2010 {
2011 	struct hfi1_ibport *ibp;
2012 	enum ib_wc_status status;
2013 	struct hfi1_qp_priv *qpriv = qp->priv;
2014 	struct rvt_swqe *wqe;
2015 	int ret = 0;
2016 	u32 ack_psn;
2017 	int diff;
2018 	struct rvt_dev_info *rdi;
2019 
2020 	lockdep_assert_held(&qp->s_lock);
2021 	/*
2022 	 * Note that NAKs implicitly ACK outstanding SEND and RDMA write
2023 	 * requests and implicitly NAK RDMA read and atomic requests issued
2024 	 * before the NAK'ed request.  The MSN won't include the NAK'ed
2025 	 * request but will include an ACK'ed request(s).
2026 	 */
2027 	ack_psn = psn;
2028 	if (aeth >> IB_AETH_NAK_SHIFT)
2029 		ack_psn--;
2030 	wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
2031 	ibp = rcd_to_iport(rcd);
2032 
2033 	/*
2034 	 * The MSN might be for a later WQE than the PSN indicates so
2035 	 * only complete WQEs that the PSN finishes.
2036 	 */
2037 	while ((diff = delta_psn(ack_psn, wqe->lpsn)) >= 0) {
2038 		/*
2039 		 * RDMA_READ_RESPONSE_ONLY is a special case since
2040 		 * we want to generate completion events for everything
2041 		 * before the RDMA read, copy the data, then generate
2042 		 * the completion for the read.
2043 		 */
2044 		if (wqe->wr.opcode == IB_WR_RDMA_READ &&
2045 		    opcode == OP(RDMA_READ_RESPONSE_ONLY) &&
2046 		    diff == 0) {
2047 			ret = 1;
2048 			goto bail_stop;
2049 		}
2050 		/*
2051 		 * If this request is a RDMA read or atomic, and the ACK is
2052 		 * for a later operation, this ACK NAKs the RDMA read or
2053 		 * atomic.  In other words, only a RDMA_READ_LAST or ONLY
2054 		 * can ACK a RDMA read and likewise for atomic ops.  Note
2055 		 * that the NAK case can only happen if relaxed ordering is
2056 		 * used and requests are sent after an RDMA read or atomic
2057 		 * is sent but before the response is received.
2058 		 */
2059 		if ((wqe->wr.opcode == IB_WR_RDMA_READ &&
2060 		     (opcode != OP(RDMA_READ_RESPONSE_LAST) || diff != 0)) ||
2061 		    (wqe->wr.opcode == IB_WR_TID_RDMA_READ &&
2062 		     (opcode != TID_OP(READ_RESP) || diff != 0)) ||
2063 		    ((wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
2064 		      wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) &&
2065 		     (opcode != OP(ATOMIC_ACKNOWLEDGE) || diff != 0)) ||
2066 		    (wqe->wr.opcode == IB_WR_TID_RDMA_WRITE &&
2067 		     (delta_psn(psn, qp->s_last_psn) != 1))) {
2068 			set_restart_qp(qp, rcd);
2069 			/*
2070 			 * No need to process the ACK/NAK since we are
2071 			 * restarting an earlier request.
2072 			 */
2073 			goto bail_stop;
2074 		}
2075 		if (wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
2076 		    wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) {
2077 			u64 *vaddr = wqe->sg_list[0].vaddr;
2078 			*vaddr = val;
2079 		}
2080 		if (wqe->wr.opcode == IB_WR_OPFN)
2081 			opfn_conn_reply(qp, val);
2082 
2083 		if (qp->s_num_rd_atomic &&
2084 		    (wqe->wr.opcode == IB_WR_RDMA_READ ||
2085 		     wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
2086 		     wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)) {
2087 			qp->s_num_rd_atomic--;
2088 			/* Restart sending task if fence is complete */
2089 			if ((qp->s_flags & RVT_S_WAIT_FENCE) &&
2090 			    !qp->s_num_rd_atomic) {
2091 				qp->s_flags &= ~(RVT_S_WAIT_FENCE |
2092 						 RVT_S_WAIT_ACK);
2093 				hfi1_schedule_send(qp);
2094 			} else if (qp->s_flags & RVT_S_WAIT_RDMAR) {
2095 				qp->s_flags &= ~(RVT_S_WAIT_RDMAR |
2096 						 RVT_S_WAIT_ACK);
2097 				hfi1_schedule_send(qp);
2098 			}
2099 		}
2100 
2101 		/*
2102 		 * TID RDMA WRITE requests will be completed by the TID RDMA
2103 		 * ACK packet handler (see tid_rdma.c).
2104 		 */
2105 		if (wqe->wr.opcode == IB_WR_TID_RDMA_WRITE)
2106 			break;
2107 
2108 		wqe = do_rc_completion(qp, wqe, ibp);
2109 		if (qp->s_acked == qp->s_tail)
2110 			break;
2111 	}
2112 
2113 	trace_hfi1_rc_ack_do(qp, aeth, psn, wqe);
2114 	trace_hfi1_sender_do_rc_ack(qp);
2115 	switch (aeth >> IB_AETH_NAK_SHIFT) {
2116 	case 0:         /* ACK */
2117 		this_cpu_inc(*ibp->rvp.rc_acks);
2118 		if (wqe->wr.opcode == IB_WR_TID_RDMA_READ) {
2119 			if (wqe_to_tid_req(wqe)->ack_pending)
2120 				rvt_mod_retry_timer_ext(qp,
2121 							qpriv->timeout_shift);
2122 			else
2123 				rvt_stop_rc_timers(qp);
2124 		} else if (qp->s_acked != qp->s_tail) {
2125 			struct rvt_swqe *__w = NULL;
2126 
2127 			if (qpriv->s_tid_cur != HFI1_QP_WQE_INVALID)
2128 				__w = rvt_get_swqe_ptr(qp, qpriv->s_tid_cur);
2129 
2130 			/*
2131 			 * Stop timers if we've received all of the TID RDMA
2132 			 * WRITE * responses.
2133 			 */
2134 			if (__w && __w->wr.opcode == IB_WR_TID_RDMA_WRITE &&
2135 			    opcode == TID_OP(WRITE_RESP)) {
2136 				/*
2137 				 * Normally, the loop above would correctly
2138 				 * process all WQEs from s_acked onward and
2139 				 * either complete them or check for correct
2140 				 * PSN sequencing.
2141 				 * However, for TID RDMA, due to pipelining,
2142 				 * the response may not be for the request at
2143 				 * s_acked so the above look would just be
2144 				 * skipped. This does not allow for checking
2145 				 * the PSN sequencing. It has to be done
2146 				 * separately.
2147 				 */
2148 				if (cmp_psn(psn, qp->s_last_psn + 1)) {
2149 					set_restart_qp(qp, rcd);
2150 					goto bail_stop;
2151 				}
2152 				/*
2153 				 * If the psn is being resent, stop the
2154 				 * resending.
2155 				 */
2156 				if (qp->s_cur != qp->s_tail &&
2157 				    cmp_psn(qp->s_psn, psn) <= 0)
2158 					update_qp_retry_state(qp, psn,
2159 							      __w->psn,
2160 							      __w->lpsn);
2161 				else if (--qpriv->pending_tid_w_resp)
2162 					rvt_mod_retry_timer(qp);
2163 				else
2164 					rvt_stop_rc_timers(qp);
2165 			} else {
2166 				/*
2167 				 * We are expecting more ACKs so
2168 				 * mod the retry timer.
2169 				 */
2170 				rvt_mod_retry_timer(qp);
2171 				/*
2172 				 * We can stop re-sending the earlier packets
2173 				 * and continue with the next packet the
2174 				 * receiver wants.
2175 				 */
2176 				if (cmp_psn(qp->s_psn, psn) <= 0)
2177 					reset_psn(qp, psn + 1);
2178 			}
2179 		} else {
2180 			/* No more acks - kill all timers */
2181 			rvt_stop_rc_timers(qp);
2182 			if (cmp_psn(qp->s_psn, psn) <= 0) {
2183 				qp->s_state = OP(SEND_LAST);
2184 				qp->s_psn = psn + 1;
2185 			}
2186 		}
2187 		if (qp->s_flags & RVT_S_WAIT_ACK) {
2188 			qp->s_flags &= ~RVT_S_WAIT_ACK;
2189 			hfi1_schedule_send(qp);
2190 		}
2191 		rvt_get_credit(qp, aeth);
2192 		qp->s_rnr_retry = qp->s_rnr_retry_cnt;
2193 		qp->s_retry = qp->s_retry_cnt;
2194 		/*
2195 		 * If the current request is a TID RDMA WRITE request and the
2196 		 * response is not a TID RDMA WRITE RESP packet, s_last_psn
2197 		 * can't be advanced.
2198 		 */
2199 		if (wqe->wr.opcode == IB_WR_TID_RDMA_WRITE &&
2200 		    opcode != TID_OP(WRITE_RESP) &&
2201 		    cmp_psn(psn, wqe->psn) >= 0)
2202 			return 1;
2203 		update_last_psn(qp, psn);
2204 		return 1;
2205 
2206 	case 1:         /* RNR NAK */
2207 		ibp->rvp.n_rnr_naks++;
2208 		if (qp->s_acked == qp->s_tail)
2209 			goto bail_stop;
2210 		if (qp->s_flags & RVT_S_WAIT_RNR)
2211 			goto bail_stop;
2212 		rdi = ib_to_rvt(qp->ibqp.device);
2213 		if (qp->s_rnr_retry == 0 &&
2214 		    !((rdi->post_parms[wqe->wr.opcode].flags &
2215 		      RVT_OPERATION_IGN_RNR_CNT) &&
2216 		      qp->s_rnr_retry_cnt == 0)) {
2217 			status = IB_WC_RNR_RETRY_EXC_ERR;
2218 			goto class_b;
2219 		}
2220 		if (qp->s_rnr_retry_cnt < 7 && qp->s_rnr_retry_cnt > 0)
2221 			qp->s_rnr_retry--;
2222 
2223 		/*
2224 		 * The last valid PSN is the previous PSN. For TID RDMA WRITE
2225 		 * request, s_last_psn should be incremented only when a TID
2226 		 * RDMA WRITE RESP is received to avoid skipping lost TID RDMA
2227 		 * WRITE RESP packets.
2228 		 */
2229 		if (wqe->wr.opcode == IB_WR_TID_RDMA_WRITE) {
2230 			reset_psn(qp, qp->s_last_psn + 1);
2231 		} else {
2232 			update_last_psn(qp, psn - 1);
2233 			reset_psn(qp, psn);
2234 		}
2235 
2236 		ibp->rvp.n_rc_resends += delta_psn(qp->s_psn, psn);
2237 		qp->s_flags &= ~(RVT_S_WAIT_SSN_CREDIT | RVT_S_WAIT_ACK);
2238 		rvt_stop_rc_timers(qp);
2239 		rvt_add_rnr_timer(qp, aeth);
2240 		return 0;
2241 
2242 	case 3:         /* NAK */
2243 		if (qp->s_acked == qp->s_tail)
2244 			goto bail_stop;
2245 		/* The last valid PSN is the previous PSN. */
2246 		update_last_psn(qp, psn - 1);
2247 		switch ((aeth >> IB_AETH_CREDIT_SHIFT) &
2248 			IB_AETH_CREDIT_MASK) {
2249 		case 0: /* PSN sequence error */
2250 			ibp->rvp.n_seq_naks++;
2251 			/*
2252 			 * Back up to the responder's expected PSN.
2253 			 * Note that we might get a NAK in the middle of an
2254 			 * RDMA READ response which terminates the RDMA
2255 			 * READ.
2256 			 */
2257 			hfi1_restart_rc(qp, psn, 0);
2258 			hfi1_schedule_send(qp);
2259 			break;
2260 
2261 		case 1: /* Invalid Request */
2262 			status = IB_WC_REM_INV_REQ_ERR;
2263 			ibp->rvp.n_other_naks++;
2264 			goto class_b;
2265 
2266 		case 2: /* Remote Access Error */
2267 			status = IB_WC_REM_ACCESS_ERR;
2268 			ibp->rvp.n_other_naks++;
2269 			goto class_b;
2270 
2271 		case 3: /* Remote Operation Error */
2272 			status = IB_WC_REM_OP_ERR;
2273 			ibp->rvp.n_other_naks++;
2274 class_b:
2275 			if (qp->s_last == qp->s_acked) {
2276 				if (wqe->wr.opcode == IB_WR_TID_RDMA_READ)
2277 					hfi1_kern_read_tid_flow_free(qp);
2278 
2279 				hfi1_trdma_send_complete(qp, wqe, status);
2280 				rvt_error_qp(qp, IB_WC_WR_FLUSH_ERR);
2281 			}
2282 			break;
2283 
2284 		default:
2285 			/* Ignore other reserved NAK error codes */
2286 			goto reserved;
2287 		}
2288 		qp->s_retry = qp->s_retry_cnt;
2289 		qp->s_rnr_retry = qp->s_rnr_retry_cnt;
2290 		goto bail_stop;
2291 
2292 	default:                /* 2: reserved */
2293 reserved:
2294 		/* Ignore reserved NAK codes. */
2295 		goto bail_stop;
2296 	}
2297 	/* cannot be reached  */
2298 bail_stop:
2299 	rvt_stop_rc_timers(qp);
2300 	return ret;
2301 }
2302 
2303 /*
2304  * We have seen an out of sequence RDMA read middle or last packet.
2305  * This ACKs SENDs and RDMA writes up to the first RDMA read or atomic SWQE.
2306  */
2307 static void rdma_seq_err(struct rvt_qp *qp, struct hfi1_ibport *ibp, u32 psn,
2308 			 struct hfi1_ctxtdata *rcd)
2309 {
2310 	struct rvt_swqe *wqe;
2311 
2312 	lockdep_assert_held(&qp->s_lock);
2313 	/* Remove QP from retry timer */
2314 	rvt_stop_rc_timers(qp);
2315 
2316 	wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
2317 
2318 	while (cmp_psn(psn, wqe->lpsn) > 0) {
2319 		if (wqe->wr.opcode == IB_WR_RDMA_READ ||
2320 		    wqe->wr.opcode == IB_WR_TID_RDMA_READ ||
2321 		    wqe->wr.opcode == IB_WR_TID_RDMA_WRITE ||
2322 		    wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
2323 		    wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)
2324 			break;
2325 		wqe = do_rc_completion(qp, wqe, ibp);
2326 	}
2327 
2328 	ibp->rvp.n_rdma_seq++;
2329 	qp->r_flags |= RVT_R_RDMAR_SEQ;
2330 	hfi1_restart_rc(qp, qp->s_last_psn + 1, 0);
2331 	if (list_empty(&qp->rspwait)) {
2332 		qp->r_flags |= RVT_R_RSP_SEND;
2333 		rvt_get_qp(qp);
2334 		list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
2335 	}
2336 }
2337 
2338 /**
2339  * rc_rcv_resp - process an incoming RC response packet
2340  * @packet: data packet information
2341  *
2342  * This is called from hfi1_rc_rcv() to process an incoming RC response
2343  * packet for the given QP.
2344  * Called at interrupt level.
2345  */
2346 static void rc_rcv_resp(struct hfi1_packet *packet)
2347 {
2348 	struct hfi1_ctxtdata *rcd = packet->rcd;
2349 	void *data = packet->payload;
2350 	u32 tlen = packet->tlen;
2351 	struct rvt_qp *qp = packet->qp;
2352 	struct hfi1_ibport *ibp;
2353 	struct ib_other_headers *ohdr = packet->ohdr;
2354 	struct rvt_swqe *wqe;
2355 	enum ib_wc_status status;
2356 	unsigned long flags;
2357 	int diff;
2358 	u64 val;
2359 	u32 aeth;
2360 	u32 psn = ib_bth_get_psn(packet->ohdr);
2361 	u32 pmtu = qp->pmtu;
2362 	u16 hdrsize = packet->hlen;
2363 	u8 opcode = packet->opcode;
2364 	u8 pad = packet->pad;
2365 	u8 extra_bytes = pad + packet->extra_byte + (SIZE_OF_CRC << 2);
2366 
2367 	spin_lock_irqsave(&qp->s_lock, flags);
2368 	trace_hfi1_ack(qp, psn);
2369 
2370 	/* Ignore invalid responses. */
2371 	if (cmp_psn(psn, READ_ONCE(qp->s_next_psn)) >= 0)
2372 		goto ack_done;
2373 
2374 	/* Ignore duplicate responses. */
2375 	diff = cmp_psn(psn, qp->s_last_psn);
2376 	if (unlikely(diff <= 0)) {
2377 		/* Update credits for "ghost" ACKs */
2378 		if (diff == 0 && opcode == OP(ACKNOWLEDGE)) {
2379 			aeth = be32_to_cpu(ohdr->u.aeth);
2380 			if ((aeth >> IB_AETH_NAK_SHIFT) == 0)
2381 				rvt_get_credit(qp, aeth);
2382 		}
2383 		goto ack_done;
2384 	}
2385 
2386 	/*
2387 	 * Skip everything other than the PSN we expect, if we are waiting
2388 	 * for a reply to a restarted RDMA read or atomic op.
2389 	 */
2390 	if (qp->r_flags & RVT_R_RDMAR_SEQ) {
2391 		if (cmp_psn(psn, qp->s_last_psn + 1) != 0)
2392 			goto ack_done;
2393 		qp->r_flags &= ~RVT_R_RDMAR_SEQ;
2394 	}
2395 
2396 	if (unlikely(qp->s_acked == qp->s_tail))
2397 		goto ack_done;
2398 	wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
2399 	status = IB_WC_SUCCESS;
2400 
2401 	switch (opcode) {
2402 	case OP(ACKNOWLEDGE):
2403 	case OP(ATOMIC_ACKNOWLEDGE):
2404 	case OP(RDMA_READ_RESPONSE_FIRST):
2405 		aeth = be32_to_cpu(ohdr->u.aeth);
2406 		if (opcode == OP(ATOMIC_ACKNOWLEDGE))
2407 			val = ib_u64_get(&ohdr->u.at.atomic_ack_eth);
2408 		else
2409 			val = 0;
2410 		if (!do_rc_ack(qp, aeth, psn, opcode, val, rcd) ||
2411 		    opcode != OP(RDMA_READ_RESPONSE_FIRST))
2412 			goto ack_done;
2413 		wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
2414 		if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
2415 			goto ack_op_err;
2416 		/*
2417 		 * If this is a response to a resent RDMA read, we
2418 		 * have to be careful to copy the data to the right
2419 		 * location.
2420 		 */
2421 		qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
2422 						  wqe, psn, pmtu);
2423 		goto read_middle;
2424 
2425 	case OP(RDMA_READ_RESPONSE_MIDDLE):
2426 		/* no AETH, no ACK */
2427 		if (unlikely(cmp_psn(psn, qp->s_last_psn + 1)))
2428 			goto ack_seq_err;
2429 		if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
2430 			goto ack_op_err;
2431 read_middle:
2432 		if (unlikely(tlen != (hdrsize + pmtu + extra_bytes)))
2433 			goto ack_len_err;
2434 		if (unlikely(pmtu >= qp->s_rdma_read_len))
2435 			goto ack_len_err;
2436 
2437 		/*
2438 		 * We got a response so update the timeout.
2439 		 * 4.096 usec. * (1 << qp->timeout)
2440 		 */
2441 		rvt_mod_retry_timer(qp);
2442 		if (qp->s_flags & RVT_S_WAIT_ACK) {
2443 			qp->s_flags &= ~RVT_S_WAIT_ACK;
2444 			hfi1_schedule_send(qp);
2445 		}
2446 
2447 		if (opcode == OP(RDMA_READ_RESPONSE_MIDDLE))
2448 			qp->s_retry = qp->s_retry_cnt;
2449 
2450 		/*
2451 		 * Update the RDMA receive state but do the copy w/o
2452 		 * holding the locks and blocking interrupts.
2453 		 */
2454 		qp->s_rdma_read_len -= pmtu;
2455 		update_last_psn(qp, psn);
2456 		spin_unlock_irqrestore(&qp->s_lock, flags);
2457 		rvt_copy_sge(qp, &qp->s_rdma_read_sge,
2458 			     data, pmtu, false, false);
2459 		goto bail;
2460 
2461 	case OP(RDMA_READ_RESPONSE_ONLY):
2462 		aeth = be32_to_cpu(ohdr->u.aeth);
2463 		if (!do_rc_ack(qp, aeth, psn, opcode, 0, rcd))
2464 			goto ack_done;
2465 		/*
2466 		 * Check that the data size is >= 0 && <= pmtu.
2467 		 * Remember to account for ICRC (4).
2468 		 */
2469 		if (unlikely(tlen < (hdrsize + extra_bytes)))
2470 			goto ack_len_err;
2471 		/*
2472 		 * If this is a response to a resent RDMA read, we
2473 		 * have to be careful to copy the data to the right
2474 		 * location.
2475 		 */
2476 		wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
2477 		qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
2478 						  wqe, psn, pmtu);
2479 		goto read_last;
2480 
2481 	case OP(RDMA_READ_RESPONSE_LAST):
2482 		/* ACKs READ req. */
2483 		if (unlikely(cmp_psn(psn, qp->s_last_psn + 1)))
2484 			goto ack_seq_err;
2485 		if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
2486 			goto ack_op_err;
2487 		/*
2488 		 * Check that the data size is >= 1 && <= pmtu.
2489 		 * Remember to account for ICRC (4).
2490 		 */
2491 		if (unlikely(tlen <= (hdrsize + extra_bytes)))
2492 			goto ack_len_err;
2493 read_last:
2494 		tlen -= hdrsize + extra_bytes;
2495 		if (unlikely(tlen != qp->s_rdma_read_len))
2496 			goto ack_len_err;
2497 		aeth = be32_to_cpu(ohdr->u.aeth);
2498 		rvt_copy_sge(qp, &qp->s_rdma_read_sge,
2499 			     data, tlen, false, false);
2500 		WARN_ON(qp->s_rdma_read_sge.num_sge);
2501 		(void)do_rc_ack(qp, aeth, psn,
2502 				 OP(RDMA_READ_RESPONSE_LAST), 0, rcd);
2503 		goto ack_done;
2504 	}
2505 
2506 ack_op_err:
2507 	status = IB_WC_LOC_QP_OP_ERR;
2508 	goto ack_err;
2509 
2510 ack_seq_err:
2511 	ibp = rcd_to_iport(rcd);
2512 	rdma_seq_err(qp, ibp, psn, rcd);
2513 	goto ack_done;
2514 
2515 ack_len_err:
2516 	status = IB_WC_LOC_LEN_ERR;
2517 ack_err:
2518 	if (qp->s_last == qp->s_acked) {
2519 		rvt_send_complete(qp, wqe, status);
2520 		rvt_error_qp(qp, IB_WC_WR_FLUSH_ERR);
2521 	}
2522 ack_done:
2523 	spin_unlock_irqrestore(&qp->s_lock, flags);
2524 bail:
2525 	return;
2526 }
2527 
2528 static inline void rc_cancel_ack(struct rvt_qp *qp)
2529 {
2530 	qp->r_adefered = 0;
2531 	if (list_empty(&qp->rspwait))
2532 		return;
2533 	list_del_init(&qp->rspwait);
2534 	qp->r_flags &= ~RVT_R_RSP_NAK;
2535 	rvt_put_qp(qp);
2536 }
2537 
2538 /**
2539  * rc_rcv_error - process an incoming duplicate or error RC packet
2540  * @ohdr: the other headers for this packet
2541  * @data: the packet data
2542  * @qp: the QP for this packet
2543  * @opcode: the opcode for this packet
2544  * @psn: the packet sequence number for this packet
2545  * @diff: the difference between the PSN and the expected PSN
2546  *
2547  * This is called from hfi1_rc_rcv() to process an unexpected
2548  * incoming RC packet for the given QP.
2549  * Called at interrupt level.
2550  * Return 1 if no more processing is needed; otherwise return 0 to
2551  * schedule a response to be sent.
2552  */
2553 static noinline int rc_rcv_error(struct ib_other_headers *ohdr, void *data,
2554 				 struct rvt_qp *qp, u32 opcode, u32 psn,
2555 				 int diff, struct hfi1_ctxtdata *rcd)
2556 {
2557 	struct hfi1_ibport *ibp = rcd_to_iport(rcd);
2558 	struct rvt_ack_entry *e;
2559 	unsigned long flags;
2560 	u8 prev;
2561 	u8 mra; /* most recent ACK */
2562 	bool old_req;
2563 
2564 	trace_hfi1_rcv_error(qp, psn);
2565 	if (diff > 0) {
2566 		/*
2567 		 * Packet sequence error.
2568 		 * A NAK will ACK earlier sends and RDMA writes.
2569 		 * Don't queue the NAK if we already sent one.
2570 		 */
2571 		if (!qp->r_nak_state) {
2572 			ibp->rvp.n_rc_seqnak++;
2573 			qp->r_nak_state = IB_NAK_PSN_ERROR;
2574 			/* Use the expected PSN. */
2575 			qp->r_ack_psn = qp->r_psn;
2576 			/*
2577 			 * Wait to send the sequence NAK until all packets
2578 			 * in the receive queue have been processed.
2579 			 * Otherwise, we end up propagating congestion.
2580 			 */
2581 			rc_defered_ack(rcd, qp);
2582 		}
2583 		goto done;
2584 	}
2585 
2586 	/*
2587 	 * Handle a duplicate request.  Don't re-execute SEND, RDMA
2588 	 * write or atomic op.  Don't NAK errors, just silently drop
2589 	 * the duplicate request.  Note that r_sge, r_len, and
2590 	 * r_rcv_len may be in use so don't modify them.
2591 	 *
2592 	 * We are supposed to ACK the earliest duplicate PSN but we
2593 	 * can coalesce an outstanding duplicate ACK.  We have to
2594 	 * send the earliest so that RDMA reads can be restarted at
2595 	 * the requester's expected PSN.
2596 	 *
2597 	 * First, find where this duplicate PSN falls within the
2598 	 * ACKs previously sent.
2599 	 * old_req is true if there is an older response that is scheduled
2600 	 * to be sent before sending this one.
2601 	 */
2602 	e = NULL;
2603 	old_req = 1;
2604 	ibp->rvp.n_rc_dupreq++;
2605 
2606 	spin_lock_irqsave(&qp->s_lock, flags);
2607 
2608 	e = find_prev_entry(qp, psn, &prev, &mra, &old_req);
2609 
2610 	switch (opcode) {
2611 	case OP(RDMA_READ_REQUEST): {
2612 		struct ib_reth *reth;
2613 		u32 offset;
2614 		u32 len;
2615 
2616 		/*
2617 		 * If we didn't find the RDMA read request in the ack queue,
2618 		 * we can ignore this request.
2619 		 */
2620 		if (!e || e->opcode != OP(RDMA_READ_REQUEST))
2621 			goto unlock_done;
2622 		/* RETH comes after BTH */
2623 		reth = &ohdr->u.rc.reth;
2624 		/*
2625 		 * Address range must be a subset of the original
2626 		 * request and start on pmtu boundaries.
2627 		 * We reuse the old ack_queue slot since the requester
2628 		 * should not back up and request an earlier PSN for the
2629 		 * same request.
2630 		 */
2631 		offset = delta_psn(psn, e->psn) * qp->pmtu;
2632 		len = be32_to_cpu(reth->length);
2633 		if (unlikely(offset + len != e->rdma_sge.sge_length))
2634 			goto unlock_done;
2635 		release_rdma_sge_mr(e);
2636 		if (len != 0) {
2637 			u32 rkey = be32_to_cpu(reth->rkey);
2638 			u64 vaddr = get_ib_reth_vaddr(reth);
2639 			int ok;
2640 
2641 			ok = rvt_rkey_ok(qp, &e->rdma_sge, len, vaddr, rkey,
2642 					 IB_ACCESS_REMOTE_READ);
2643 			if (unlikely(!ok))
2644 				goto unlock_done;
2645 		} else {
2646 			e->rdma_sge.vaddr = NULL;
2647 			e->rdma_sge.length = 0;
2648 			e->rdma_sge.sge_length = 0;
2649 		}
2650 		e->psn = psn;
2651 		if (old_req)
2652 			goto unlock_done;
2653 		if (qp->s_acked_ack_queue == qp->s_tail_ack_queue)
2654 			qp->s_acked_ack_queue = prev;
2655 		qp->s_tail_ack_queue = prev;
2656 		break;
2657 	}
2658 
2659 	case OP(COMPARE_SWAP):
2660 	case OP(FETCH_ADD): {
2661 		/*
2662 		 * If we didn't find the atomic request in the ack queue
2663 		 * or the send engine is already backed up to send an
2664 		 * earlier entry, we can ignore this request.
2665 		 */
2666 		if (!e || e->opcode != (u8)opcode || old_req)
2667 			goto unlock_done;
2668 		if (qp->s_tail_ack_queue == qp->s_acked_ack_queue)
2669 			qp->s_acked_ack_queue = prev;
2670 		qp->s_tail_ack_queue = prev;
2671 		break;
2672 	}
2673 
2674 	default:
2675 		/*
2676 		 * Ignore this operation if it doesn't request an ACK
2677 		 * or an earlier RDMA read or atomic is going to be resent.
2678 		 */
2679 		if (!(psn & IB_BTH_REQ_ACK) || old_req)
2680 			goto unlock_done;
2681 		/*
2682 		 * Resend the most recent ACK if this request is
2683 		 * after all the previous RDMA reads and atomics.
2684 		 */
2685 		if (mra == qp->r_head_ack_queue) {
2686 			spin_unlock_irqrestore(&qp->s_lock, flags);
2687 			qp->r_nak_state = 0;
2688 			qp->r_ack_psn = qp->r_psn - 1;
2689 			goto send_ack;
2690 		}
2691 
2692 		/*
2693 		 * Resend the RDMA read or atomic op which
2694 		 * ACKs this duplicate request.
2695 		 */
2696 		if (qp->s_tail_ack_queue == qp->s_acked_ack_queue)
2697 			qp->s_acked_ack_queue = mra;
2698 		qp->s_tail_ack_queue = mra;
2699 		break;
2700 	}
2701 	qp->s_ack_state = OP(ACKNOWLEDGE);
2702 	qp->s_flags |= RVT_S_RESP_PENDING;
2703 	qp->r_nak_state = 0;
2704 	hfi1_schedule_send(qp);
2705 
2706 unlock_done:
2707 	spin_unlock_irqrestore(&qp->s_lock, flags);
2708 done:
2709 	return 1;
2710 
2711 send_ack:
2712 	return 0;
2713 }
2714 
2715 static void log_cca_event(struct hfi1_pportdata *ppd, u8 sl, u32 rlid,
2716 			  u32 lqpn, u32 rqpn, u8 svc_type)
2717 {
2718 	struct opa_hfi1_cong_log_event_internal *cc_event;
2719 	unsigned long flags;
2720 
2721 	if (sl >= OPA_MAX_SLS)
2722 		return;
2723 
2724 	spin_lock_irqsave(&ppd->cc_log_lock, flags);
2725 
2726 	ppd->threshold_cong_event_map[sl / 8] |= 1 << (sl % 8);
2727 	ppd->threshold_event_counter++;
2728 
2729 	cc_event = &ppd->cc_events[ppd->cc_log_idx++];
2730 	if (ppd->cc_log_idx == OPA_CONG_LOG_ELEMS)
2731 		ppd->cc_log_idx = 0;
2732 	cc_event->lqpn = lqpn & RVT_QPN_MASK;
2733 	cc_event->rqpn = rqpn & RVT_QPN_MASK;
2734 	cc_event->sl = sl;
2735 	cc_event->svc_type = svc_type;
2736 	cc_event->rlid = rlid;
2737 	/* keep timestamp in units of 1.024 usec */
2738 	cc_event->timestamp = ktime_get_ns() / 1024;
2739 
2740 	spin_unlock_irqrestore(&ppd->cc_log_lock, flags);
2741 }
2742 
2743 void process_becn(struct hfi1_pportdata *ppd, u8 sl, u32 rlid, u32 lqpn,
2744 		  u32 rqpn, u8 svc_type)
2745 {
2746 	struct cca_timer *cca_timer;
2747 	u16 ccti, ccti_incr, ccti_timer, ccti_limit;
2748 	u8 trigger_threshold;
2749 	struct cc_state *cc_state;
2750 	unsigned long flags;
2751 
2752 	if (sl >= OPA_MAX_SLS)
2753 		return;
2754 
2755 	cc_state = get_cc_state(ppd);
2756 
2757 	if (!cc_state)
2758 		return;
2759 
2760 	/*
2761 	 * 1) increase CCTI (for this SL)
2762 	 * 2) select IPG (i.e., call set_link_ipg())
2763 	 * 3) start timer
2764 	 */
2765 	ccti_limit = cc_state->cct.ccti_limit;
2766 	ccti_incr = cc_state->cong_setting.entries[sl].ccti_increase;
2767 	ccti_timer = cc_state->cong_setting.entries[sl].ccti_timer;
2768 	trigger_threshold =
2769 		cc_state->cong_setting.entries[sl].trigger_threshold;
2770 
2771 	spin_lock_irqsave(&ppd->cca_timer_lock, flags);
2772 
2773 	cca_timer = &ppd->cca_timer[sl];
2774 	if (cca_timer->ccti < ccti_limit) {
2775 		if (cca_timer->ccti + ccti_incr <= ccti_limit)
2776 			cca_timer->ccti += ccti_incr;
2777 		else
2778 			cca_timer->ccti = ccti_limit;
2779 		set_link_ipg(ppd);
2780 	}
2781 
2782 	ccti = cca_timer->ccti;
2783 
2784 	if (!hrtimer_active(&cca_timer->hrtimer)) {
2785 		/* ccti_timer is in units of 1.024 usec */
2786 		unsigned long nsec = 1024 * ccti_timer;
2787 
2788 		hrtimer_start(&cca_timer->hrtimer, ns_to_ktime(nsec),
2789 			      HRTIMER_MODE_REL_PINNED);
2790 	}
2791 
2792 	spin_unlock_irqrestore(&ppd->cca_timer_lock, flags);
2793 
2794 	if ((trigger_threshold != 0) && (ccti >= trigger_threshold))
2795 		log_cca_event(ppd, sl, rlid, lqpn, rqpn, svc_type);
2796 }
2797 
2798 /**
2799  * hfi1_rc_rcv - process an incoming RC packet
2800  * @packet: data packet information
2801  *
2802  * This is called from qp_rcv() to process an incoming RC packet
2803  * for the given QP.
2804  * May be called at interrupt level.
2805  */
2806 void hfi1_rc_rcv(struct hfi1_packet *packet)
2807 {
2808 	struct hfi1_ctxtdata *rcd = packet->rcd;
2809 	void *data = packet->payload;
2810 	u32 tlen = packet->tlen;
2811 	struct rvt_qp *qp = packet->qp;
2812 	struct hfi1_qp_priv *qpriv = qp->priv;
2813 	struct hfi1_ibport *ibp = rcd_to_iport(rcd);
2814 	struct ib_other_headers *ohdr = packet->ohdr;
2815 	u32 opcode = packet->opcode;
2816 	u32 hdrsize = packet->hlen;
2817 	u32 psn = ib_bth_get_psn(packet->ohdr);
2818 	u32 pad = packet->pad;
2819 	struct ib_wc wc;
2820 	u32 pmtu = qp->pmtu;
2821 	int diff;
2822 	struct ib_reth *reth;
2823 	unsigned long flags;
2824 	int ret;
2825 	bool copy_last = false, fecn;
2826 	u32 rkey;
2827 	u8 extra_bytes = pad + packet->extra_byte + (SIZE_OF_CRC << 2);
2828 
2829 	lockdep_assert_held(&qp->r_lock);
2830 
2831 	if (hfi1_ruc_check_hdr(ibp, packet))
2832 		return;
2833 
2834 	fecn = process_ecn(qp, packet);
2835 	opfn_trigger_conn_request(qp, be32_to_cpu(ohdr->bth[1]));
2836 
2837 	/*
2838 	 * Process responses (ACKs) before anything else.  Note that the
2839 	 * packet sequence number will be for something in the send work
2840 	 * queue rather than the expected receive packet sequence number.
2841 	 * In other words, this QP is the requester.
2842 	 */
2843 	if (opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
2844 	    opcode <= OP(ATOMIC_ACKNOWLEDGE)) {
2845 		rc_rcv_resp(packet);
2846 		return;
2847 	}
2848 
2849 	/* Compute 24 bits worth of difference. */
2850 	diff = delta_psn(psn, qp->r_psn);
2851 	if (unlikely(diff)) {
2852 		if (rc_rcv_error(ohdr, data, qp, opcode, psn, diff, rcd))
2853 			return;
2854 		goto send_ack;
2855 	}
2856 
2857 	/* Check for opcode sequence errors. */
2858 	switch (qp->r_state) {
2859 	case OP(SEND_FIRST):
2860 	case OP(SEND_MIDDLE):
2861 		if (opcode == OP(SEND_MIDDLE) ||
2862 		    opcode == OP(SEND_LAST) ||
2863 		    opcode == OP(SEND_LAST_WITH_IMMEDIATE) ||
2864 		    opcode == OP(SEND_LAST_WITH_INVALIDATE))
2865 			break;
2866 		goto nack_inv;
2867 
2868 	case OP(RDMA_WRITE_FIRST):
2869 	case OP(RDMA_WRITE_MIDDLE):
2870 		if (opcode == OP(RDMA_WRITE_MIDDLE) ||
2871 		    opcode == OP(RDMA_WRITE_LAST) ||
2872 		    opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
2873 			break;
2874 		goto nack_inv;
2875 
2876 	default:
2877 		if (opcode == OP(SEND_MIDDLE) ||
2878 		    opcode == OP(SEND_LAST) ||
2879 		    opcode == OP(SEND_LAST_WITH_IMMEDIATE) ||
2880 		    opcode == OP(SEND_LAST_WITH_INVALIDATE) ||
2881 		    opcode == OP(RDMA_WRITE_MIDDLE) ||
2882 		    opcode == OP(RDMA_WRITE_LAST) ||
2883 		    opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
2884 			goto nack_inv;
2885 		/*
2886 		 * Note that it is up to the requester to not send a new
2887 		 * RDMA read or atomic operation before receiving an ACK
2888 		 * for the previous operation.
2889 		 */
2890 		break;
2891 	}
2892 
2893 	if (qp->state == IB_QPS_RTR && !(qp->r_flags & RVT_R_COMM_EST))
2894 		rvt_comm_est(qp);
2895 
2896 	/* OK, process the packet. */
2897 	switch (opcode) {
2898 	case OP(SEND_FIRST):
2899 		ret = rvt_get_rwqe(qp, false);
2900 		if (ret < 0)
2901 			goto nack_op_err;
2902 		if (!ret)
2903 			goto rnr_nak;
2904 		qp->r_rcv_len = 0;
2905 		/* FALLTHROUGH */
2906 	case OP(SEND_MIDDLE):
2907 	case OP(RDMA_WRITE_MIDDLE):
2908 send_middle:
2909 		/* Check for invalid length PMTU or posted rwqe len. */
2910 		/*
2911 		 * There will be no padding for 9B packet but 16B packets
2912 		 * will come in with some padding since we always add
2913 		 * CRC and LT bytes which will need to be flit aligned
2914 		 */
2915 		if (unlikely(tlen != (hdrsize + pmtu + extra_bytes)))
2916 			goto nack_inv;
2917 		qp->r_rcv_len += pmtu;
2918 		if (unlikely(qp->r_rcv_len > qp->r_len))
2919 			goto nack_inv;
2920 		rvt_copy_sge(qp, &qp->r_sge, data, pmtu, true, false);
2921 		break;
2922 
2923 	case OP(RDMA_WRITE_LAST_WITH_IMMEDIATE):
2924 		/* consume RWQE */
2925 		ret = rvt_get_rwqe(qp, true);
2926 		if (ret < 0)
2927 			goto nack_op_err;
2928 		if (!ret)
2929 			goto rnr_nak;
2930 		goto send_last_imm;
2931 
2932 	case OP(SEND_ONLY):
2933 	case OP(SEND_ONLY_WITH_IMMEDIATE):
2934 	case OP(SEND_ONLY_WITH_INVALIDATE):
2935 		ret = rvt_get_rwqe(qp, false);
2936 		if (ret < 0)
2937 			goto nack_op_err;
2938 		if (!ret)
2939 			goto rnr_nak;
2940 		qp->r_rcv_len = 0;
2941 		if (opcode == OP(SEND_ONLY))
2942 			goto no_immediate_data;
2943 		if (opcode == OP(SEND_ONLY_WITH_INVALIDATE))
2944 			goto send_last_inv;
2945 		/* FALLTHROUGH -- for SEND_ONLY_WITH_IMMEDIATE */
2946 	case OP(SEND_LAST_WITH_IMMEDIATE):
2947 send_last_imm:
2948 		wc.ex.imm_data = ohdr->u.imm_data;
2949 		wc.wc_flags = IB_WC_WITH_IMM;
2950 		goto send_last;
2951 	case OP(SEND_LAST_WITH_INVALIDATE):
2952 send_last_inv:
2953 		rkey = be32_to_cpu(ohdr->u.ieth);
2954 		if (rvt_invalidate_rkey(qp, rkey))
2955 			goto no_immediate_data;
2956 		wc.ex.invalidate_rkey = rkey;
2957 		wc.wc_flags = IB_WC_WITH_INVALIDATE;
2958 		goto send_last;
2959 	case OP(RDMA_WRITE_LAST):
2960 		copy_last = rvt_is_user_qp(qp);
2961 		/* fall through */
2962 	case OP(SEND_LAST):
2963 no_immediate_data:
2964 		wc.wc_flags = 0;
2965 		wc.ex.imm_data = 0;
2966 send_last:
2967 		/* Check for invalid length. */
2968 		/* LAST len should be >= 1 */
2969 		if (unlikely(tlen < (hdrsize + extra_bytes)))
2970 			goto nack_inv;
2971 		/* Don't count the CRC(and padding and LT byte for 16B). */
2972 		tlen -= (hdrsize + extra_bytes);
2973 		wc.byte_len = tlen + qp->r_rcv_len;
2974 		if (unlikely(wc.byte_len > qp->r_len))
2975 			goto nack_inv;
2976 		rvt_copy_sge(qp, &qp->r_sge, data, tlen, true, copy_last);
2977 		rvt_put_ss(&qp->r_sge);
2978 		qp->r_msn++;
2979 		if (!__test_and_clear_bit(RVT_R_WRID_VALID, &qp->r_aflags))
2980 			break;
2981 		wc.wr_id = qp->r_wr_id;
2982 		wc.status = IB_WC_SUCCESS;
2983 		if (opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE) ||
2984 		    opcode == OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE))
2985 			wc.opcode = IB_WC_RECV_RDMA_WITH_IMM;
2986 		else
2987 			wc.opcode = IB_WC_RECV;
2988 		wc.qp = &qp->ibqp;
2989 		wc.src_qp = qp->remote_qpn;
2990 		wc.slid = rdma_ah_get_dlid(&qp->remote_ah_attr) & U16_MAX;
2991 		/*
2992 		 * It seems that IB mandates the presence of an SL in a
2993 		 * work completion only for the UD transport (see section
2994 		 * 11.4.2 of IBTA Vol. 1).
2995 		 *
2996 		 * However, the way the SL is chosen below is consistent
2997 		 * with the way that IB/qib works and is trying avoid
2998 		 * introducing incompatibilities.
2999 		 *
3000 		 * See also OPA Vol. 1, section 9.7.6, and table 9-17.
3001 		 */
3002 		wc.sl = rdma_ah_get_sl(&qp->remote_ah_attr);
3003 		/* zero fields that are N/A */
3004 		wc.vendor_err = 0;
3005 		wc.pkey_index = 0;
3006 		wc.dlid_path_bits = 0;
3007 		wc.port_num = 0;
3008 		/* Signal completion event if the solicited bit is set. */
3009 		rvt_recv_cq(qp, &wc, ib_bth_is_solicited(ohdr));
3010 		break;
3011 
3012 	case OP(RDMA_WRITE_ONLY):
3013 		copy_last = rvt_is_user_qp(qp);
3014 		/* fall through */
3015 	case OP(RDMA_WRITE_FIRST):
3016 	case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE):
3017 		if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_WRITE)))
3018 			goto nack_inv;
3019 		/* consume RWQE */
3020 		reth = &ohdr->u.rc.reth;
3021 		qp->r_len = be32_to_cpu(reth->length);
3022 		qp->r_rcv_len = 0;
3023 		qp->r_sge.sg_list = NULL;
3024 		if (qp->r_len != 0) {
3025 			u32 rkey = be32_to_cpu(reth->rkey);
3026 			u64 vaddr = get_ib_reth_vaddr(reth);
3027 			int ok;
3028 
3029 			/* Check rkey & NAK */
3030 			ok = rvt_rkey_ok(qp, &qp->r_sge.sge, qp->r_len, vaddr,
3031 					 rkey, IB_ACCESS_REMOTE_WRITE);
3032 			if (unlikely(!ok))
3033 				goto nack_acc;
3034 			qp->r_sge.num_sge = 1;
3035 		} else {
3036 			qp->r_sge.num_sge = 0;
3037 			qp->r_sge.sge.mr = NULL;
3038 			qp->r_sge.sge.vaddr = NULL;
3039 			qp->r_sge.sge.length = 0;
3040 			qp->r_sge.sge.sge_length = 0;
3041 		}
3042 		if (opcode == OP(RDMA_WRITE_FIRST))
3043 			goto send_middle;
3044 		else if (opcode == OP(RDMA_WRITE_ONLY))
3045 			goto no_immediate_data;
3046 		ret = rvt_get_rwqe(qp, true);
3047 		if (ret < 0)
3048 			goto nack_op_err;
3049 		if (!ret) {
3050 			/* peer will send again */
3051 			rvt_put_ss(&qp->r_sge);
3052 			goto rnr_nak;
3053 		}
3054 		wc.ex.imm_data = ohdr->u.rc.imm_data;
3055 		wc.wc_flags = IB_WC_WITH_IMM;
3056 		goto send_last;
3057 
3058 	case OP(RDMA_READ_REQUEST): {
3059 		struct rvt_ack_entry *e;
3060 		u32 len;
3061 		u8 next;
3062 
3063 		if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_READ)))
3064 			goto nack_inv;
3065 		next = qp->r_head_ack_queue + 1;
3066 		/* s_ack_queue is size rvt_size_atomic()+1 so use > not >= */
3067 		if (next > rvt_size_atomic(ib_to_rvt(qp->ibqp.device)))
3068 			next = 0;
3069 		spin_lock_irqsave(&qp->s_lock, flags);
3070 		if (unlikely(next == qp->s_acked_ack_queue)) {
3071 			if (!qp->s_ack_queue[next].sent)
3072 				goto nack_inv_unlck;
3073 			update_ack_queue(qp, next);
3074 		}
3075 		e = &qp->s_ack_queue[qp->r_head_ack_queue];
3076 		release_rdma_sge_mr(e);
3077 		reth = &ohdr->u.rc.reth;
3078 		len = be32_to_cpu(reth->length);
3079 		if (len) {
3080 			u32 rkey = be32_to_cpu(reth->rkey);
3081 			u64 vaddr = get_ib_reth_vaddr(reth);
3082 			int ok;
3083 
3084 			/* Check rkey & NAK */
3085 			ok = rvt_rkey_ok(qp, &e->rdma_sge, len, vaddr,
3086 					 rkey, IB_ACCESS_REMOTE_READ);
3087 			if (unlikely(!ok))
3088 				goto nack_acc_unlck;
3089 			/*
3090 			 * Update the next expected PSN.  We add 1 later
3091 			 * below, so only add the remainder here.
3092 			 */
3093 			qp->r_psn += rvt_div_mtu(qp, len - 1);
3094 		} else {
3095 			e->rdma_sge.mr = NULL;
3096 			e->rdma_sge.vaddr = NULL;
3097 			e->rdma_sge.length = 0;
3098 			e->rdma_sge.sge_length = 0;
3099 		}
3100 		e->opcode = opcode;
3101 		e->sent = 0;
3102 		e->psn = psn;
3103 		e->lpsn = qp->r_psn;
3104 		/*
3105 		 * We need to increment the MSN here instead of when we
3106 		 * finish sending the result since a duplicate request would
3107 		 * increment it more than once.
3108 		 */
3109 		qp->r_msn++;
3110 		qp->r_psn++;
3111 		qp->r_state = opcode;
3112 		qp->r_nak_state = 0;
3113 		qp->r_head_ack_queue = next;
3114 		qpriv->r_tid_alloc = qp->r_head_ack_queue;
3115 
3116 		/* Schedule the send engine. */
3117 		qp->s_flags |= RVT_S_RESP_PENDING;
3118 		if (fecn)
3119 			qp->s_flags |= RVT_S_ECN;
3120 		hfi1_schedule_send(qp);
3121 
3122 		spin_unlock_irqrestore(&qp->s_lock, flags);
3123 		return;
3124 	}
3125 
3126 	case OP(COMPARE_SWAP):
3127 	case OP(FETCH_ADD): {
3128 		struct ib_atomic_eth *ateth = &ohdr->u.atomic_eth;
3129 		u64 vaddr = get_ib_ateth_vaddr(ateth);
3130 		bool opfn = opcode == OP(COMPARE_SWAP) &&
3131 			vaddr == HFI1_VERBS_E_ATOMIC_VADDR;
3132 		struct rvt_ack_entry *e;
3133 		atomic64_t *maddr;
3134 		u64 sdata;
3135 		u32 rkey;
3136 		u8 next;
3137 
3138 		if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_ATOMIC) &&
3139 			     !opfn))
3140 			goto nack_inv;
3141 		next = qp->r_head_ack_queue + 1;
3142 		if (next > rvt_size_atomic(ib_to_rvt(qp->ibqp.device)))
3143 			next = 0;
3144 		spin_lock_irqsave(&qp->s_lock, flags);
3145 		if (unlikely(next == qp->s_acked_ack_queue)) {
3146 			if (!qp->s_ack_queue[next].sent)
3147 				goto nack_inv_unlck;
3148 			update_ack_queue(qp, next);
3149 		}
3150 		e = &qp->s_ack_queue[qp->r_head_ack_queue];
3151 		release_rdma_sge_mr(e);
3152 		/* Process OPFN special virtual address */
3153 		if (opfn) {
3154 			opfn_conn_response(qp, e, ateth);
3155 			goto ack;
3156 		}
3157 		if (unlikely(vaddr & (sizeof(u64) - 1)))
3158 			goto nack_inv_unlck;
3159 		rkey = be32_to_cpu(ateth->rkey);
3160 		/* Check rkey & NAK */
3161 		if (unlikely(!rvt_rkey_ok(qp, &qp->r_sge.sge, sizeof(u64),
3162 					  vaddr, rkey,
3163 					  IB_ACCESS_REMOTE_ATOMIC)))
3164 			goto nack_acc_unlck;
3165 		/* Perform atomic OP and save result. */
3166 		maddr = (atomic64_t *)qp->r_sge.sge.vaddr;
3167 		sdata = get_ib_ateth_swap(ateth);
3168 		e->atomic_data = (opcode == OP(FETCH_ADD)) ?
3169 			(u64)atomic64_add_return(sdata, maddr) - sdata :
3170 			(u64)cmpxchg((u64 *)qp->r_sge.sge.vaddr,
3171 				      get_ib_ateth_compare(ateth),
3172 				      sdata);
3173 		rvt_put_mr(qp->r_sge.sge.mr);
3174 		qp->r_sge.num_sge = 0;
3175 ack:
3176 		e->opcode = opcode;
3177 		e->sent = 0;
3178 		e->psn = psn;
3179 		e->lpsn = psn;
3180 		qp->r_msn++;
3181 		qp->r_psn++;
3182 		qp->r_state = opcode;
3183 		qp->r_nak_state = 0;
3184 		qp->r_head_ack_queue = next;
3185 		qpriv->r_tid_alloc = qp->r_head_ack_queue;
3186 
3187 		/* Schedule the send engine. */
3188 		qp->s_flags |= RVT_S_RESP_PENDING;
3189 		if (fecn)
3190 			qp->s_flags |= RVT_S_ECN;
3191 		hfi1_schedule_send(qp);
3192 
3193 		spin_unlock_irqrestore(&qp->s_lock, flags);
3194 		return;
3195 	}
3196 
3197 	default:
3198 		/* NAK unknown opcodes. */
3199 		goto nack_inv;
3200 	}
3201 	qp->r_psn++;
3202 	qp->r_state = opcode;
3203 	qp->r_ack_psn = psn;
3204 	qp->r_nak_state = 0;
3205 	/* Send an ACK if requested or required. */
3206 	if (psn & IB_BTH_REQ_ACK || fecn) {
3207 		if (packet->numpkt == 0 || fecn ||
3208 		    qp->r_adefered >= HFI1_PSN_CREDIT) {
3209 			rc_cancel_ack(qp);
3210 			goto send_ack;
3211 		}
3212 		qp->r_adefered++;
3213 		rc_defered_ack(rcd, qp);
3214 	}
3215 	return;
3216 
3217 rnr_nak:
3218 	qp->r_nak_state = qp->r_min_rnr_timer | IB_RNR_NAK;
3219 	qp->r_ack_psn = qp->r_psn;
3220 	/* Queue RNR NAK for later */
3221 	rc_defered_ack(rcd, qp);
3222 	return;
3223 
3224 nack_op_err:
3225 	rvt_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
3226 	qp->r_nak_state = IB_NAK_REMOTE_OPERATIONAL_ERROR;
3227 	qp->r_ack_psn = qp->r_psn;
3228 	/* Queue NAK for later */
3229 	rc_defered_ack(rcd, qp);
3230 	return;
3231 
3232 nack_inv_unlck:
3233 	spin_unlock_irqrestore(&qp->s_lock, flags);
3234 nack_inv:
3235 	rvt_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
3236 	qp->r_nak_state = IB_NAK_INVALID_REQUEST;
3237 	qp->r_ack_psn = qp->r_psn;
3238 	/* Queue NAK for later */
3239 	rc_defered_ack(rcd, qp);
3240 	return;
3241 
3242 nack_acc_unlck:
3243 	spin_unlock_irqrestore(&qp->s_lock, flags);
3244 nack_acc:
3245 	rvt_rc_error(qp, IB_WC_LOC_PROT_ERR);
3246 	qp->r_nak_state = IB_NAK_REMOTE_ACCESS_ERROR;
3247 	qp->r_ack_psn = qp->r_psn;
3248 send_ack:
3249 	hfi1_send_rc_ack(packet, fecn);
3250 }
3251 
3252 void hfi1_rc_hdrerr(
3253 	struct hfi1_ctxtdata *rcd,
3254 	struct hfi1_packet *packet,
3255 	struct rvt_qp *qp)
3256 {
3257 	struct hfi1_ibport *ibp = rcd_to_iport(rcd);
3258 	int diff;
3259 	u32 opcode;
3260 	u32 psn;
3261 
3262 	if (hfi1_ruc_check_hdr(ibp, packet))
3263 		return;
3264 
3265 	psn = ib_bth_get_psn(packet->ohdr);
3266 	opcode = ib_bth_get_opcode(packet->ohdr);
3267 
3268 	/* Only deal with RDMA Writes for now */
3269 	if (opcode < IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST) {
3270 		diff = delta_psn(psn, qp->r_psn);
3271 		if (!qp->r_nak_state && diff >= 0) {
3272 			ibp->rvp.n_rc_seqnak++;
3273 			qp->r_nak_state = IB_NAK_PSN_ERROR;
3274 			/* Use the expected PSN. */
3275 			qp->r_ack_psn = qp->r_psn;
3276 			/*
3277 			 * Wait to send the sequence
3278 			 * NAK until all packets
3279 			 * in the receive queue have
3280 			 * been processed.
3281 			 * Otherwise, we end up
3282 			 * propagating congestion.
3283 			 */
3284 			rc_defered_ack(rcd, qp);
3285 		} /* Out of sequence NAK */
3286 	} /* QP Request NAKs */
3287 }
3288