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IB/ipath: Fix PSN update for RC retries
[mirror_ubuntu-bionic-kernel.git] / drivers / infiniband / hw / ipath / ipath_rc.c
1 /*
2 * Copyright (c) 2006 QLogic, Inc. All rights reserved.
3 * Copyright (c) 2005, 2006 PathScale, Inc. All rights reserved.
4 *
5 * This software is available to you under a choice of one of two
6 * licenses. You may choose to be licensed under the terms of the GNU
7 * General Public License (GPL) Version 2, available from the file
8 * COPYING in the main directory of this source tree, or the
9 * OpenIB.org BSD license below:
10 *
11 * Redistribution and use in source and binary forms, with or
12 * without modification, are permitted provided that the following
13 * conditions are met:
14 *
15 * - Redistributions of source code must retain the above
16 * copyright notice, this list of conditions and the following
17 * disclaimer.
18 *
19 * - Redistributions in binary form must reproduce the above
20 * copyright notice, this list of conditions and the following
21 * disclaimer in the documentation and/or other materials
22 * provided with the distribution.
23 *
24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
28 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
29 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
30 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
31 * SOFTWARE.
32 */
33
34 #include "ipath_verbs.h"
35 #include "ipath_kernel.h"
36
37 /* cut down ridiculously long IB macro names */
38 #define OP(x) IB_OPCODE_RC_##x
39
40 static u32 restart_sge(struct ipath_sge_state *ss, struct ipath_swqe *wqe,
41 u32 psn, u32 pmtu)
42 {
43 u32 len;
44
45 len = ((psn - wqe->psn) & IPATH_PSN_MASK) * pmtu;
46 ss->sge = wqe->sg_list[0];
47 ss->sg_list = wqe->sg_list + 1;
48 ss->num_sge = wqe->wr.num_sge;
49 ipath_skip_sge(ss, len);
50 return wqe->length - len;
51 }
52
53 /**
54 * ipath_init_restart- initialize the qp->s_sge after a restart
55 * @qp: the QP who's SGE we're restarting
56 * @wqe: the work queue to initialize the QP's SGE from
57 *
58 * The QP s_lock should be held and interrupts disabled.
59 */
60 static void ipath_init_restart(struct ipath_qp *qp, struct ipath_swqe *wqe)
61 {
62 struct ipath_ibdev *dev;
63
64 qp->s_len = restart_sge(&qp->s_sge, wqe, qp->s_psn,
65 ib_mtu_enum_to_int(qp->path_mtu));
66 dev = to_idev(qp->ibqp.device);
67 spin_lock(&dev->pending_lock);
68 if (list_empty(&qp->timerwait))
69 list_add_tail(&qp->timerwait,
70 &dev->pending[dev->pending_index]);
71 spin_unlock(&dev->pending_lock);
72 }
73
74 /**
75 * ipath_make_rc_ack - construct a response packet (ACK, NAK, or RDMA read)
76 * @qp: a pointer to the QP
77 * @ohdr: a pointer to the IB header being constructed
78 * @pmtu: the path MTU
79 *
80 * Return 1 if constructed; otherwise, return 0.
81 * Note that we are in the responder's side of the QP context.
82 * Note the QP s_lock must be held.
83 */
84 static int ipath_make_rc_ack(struct ipath_qp *qp,
85 struct ipath_other_headers *ohdr,
86 u32 pmtu, u32 *bth0p, u32 *bth2p)
87 {
88 struct ipath_ack_entry *e;
89 u32 hwords;
90 u32 len;
91 u32 bth0;
92 u32 bth2;
93
94 /* header size in 32-bit words LRH+BTH = (8+12)/4. */
95 hwords = 5;
96
97 switch (qp->s_ack_state) {
98 case OP(RDMA_READ_RESPONSE_LAST):
99 case OP(RDMA_READ_RESPONSE_ONLY):
100 case OP(ATOMIC_ACKNOWLEDGE):
101 qp->s_ack_state = OP(ACKNOWLEDGE);
102 /* FALLTHROUGH */
103 case OP(ACKNOWLEDGE):
104 /* Check for no next entry in the queue. */
105 if (qp->r_head_ack_queue == qp->s_tail_ack_queue) {
106 if (qp->s_flags & IPATH_S_ACK_PENDING)
107 goto normal;
108 goto bail;
109 }
110
111 e = &qp->s_ack_queue[qp->s_tail_ack_queue];
112 if (e->opcode == OP(RDMA_READ_REQUEST)) {
113 /* Copy SGE state in case we need to resend */
114 qp->s_ack_rdma_sge = e->rdma_sge;
115 qp->s_cur_sge = &qp->s_ack_rdma_sge;
116 len = e->rdma_sge.sge.sge_length;
117 if (len > pmtu) {
118 len = pmtu;
119 qp->s_ack_state = OP(RDMA_READ_RESPONSE_FIRST);
120 } else {
121 qp->s_ack_state = OP(RDMA_READ_RESPONSE_ONLY);
122 if (++qp->s_tail_ack_queue >
123 IPATH_MAX_RDMA_ATOMIC)
124 qp->s_tail_ack_queue = 0;
125 }
126 ohdr->u.aeth = ipath_compute_aeth(qp);
127 hwords++;
128 qp->s_ack_rdma_psn = e->psn;
129 bth2 = qp->s_ack_rdma_psn++ & IPATH_PSN_MASK;
130 } else {
131 /* COMPARE_SWAP or FETCH_ADD */
132 qp->s_cur_sge = NULL;
133 len = 0;
134 qp->s_ack_state = OP(ATOMIC_ACKNOWLEDGE);
135 ohdr->u.at.aeth = ipath_compute_aeth(qp);
136 ohdr->u.at.atomic_ack_eth[0] =
137 cpu_to_be32(e->atomic_data >> 32);
138 ohdr->u.at.atomic_ack_eth[1] =
139 cpu_to_be32(e->atomic_data);
140 hwords += sizeof(ohdr->u.at) / sizeof(u32);
141 bth2 = e->psn;
142 if (++qp->s_tail_ack_queue > IPATH_MAX_RDMA_ATOMIC)
143 qp->s_tail_ack_queue = 0;
144 }
145 bth0 = qp->s_ack_state << 24;
146 break;
147
148 case OP(RDMA_READ_RESPONSE_FIRST):
149 qp->s_ack_state = OP(RDMA_READ_RESPONSE_MIDDLE);
150 /* FALLTHROUGH */
151 case OP(RDMA_READ_RESPONSE_MIDDLE):
152 len = qp->s_ack_rdma_sge.sge.sge_length;
153 if (len > pmtu)
154 len = pmtu;
155 else {
156 ohdr->u.aeth = ipath_compute_aeth(qp);
157 hwords++;
158 qp->s_ack_state = OP(RDMA_READ_RESPONSE_LAST);
159 if (++qp->s_tail_ack_queue > IPATH_MAX_RDMA_ATOMIC)
160 qp->s_tail_ack_queue = 0;
161 }
162 bth0 = qp->s_ack_state << 24;
163 bth2 = qp->s_ack_rdma_psn++ & IPATH_PSN_MASK;
164 break;
165
166 default:
167 normal:
168 /*
169 * Send a regular ACK.
170 * Set the s_ack_state so we wait until after sending
171 * the ACK before setting s_ack_state to ACKNOWLEDGE
172 * (see above).
173 */
174 qp->s_ack_state = OP(ATOMIC_ACKNOWLEDGE);
175 qp->s_flags &= ~IPATH_S_ACK_PENDING;
176 qp->s_cur_sge = NULL;
177 if (qp->s_nak_state)
178 ohdr->u.aeth =
179 cpu_to_be32((qp->r_msn & IPATH_MSN_MASK) |
180 (qp->s_nak_state <<
181 IPATH_AETH_CREDIT_SHIFT));
182 else
183 ohdr->u.aeth = ipath_compute_aeth(qp);
184 hwords++;
185 len = 0;
186 bth0 = OP(ACKNOWLEDGE) << 24;
187 bth2 = qp->s_ack_psn & IPATH_PSN_MASK;
188 }
189 qp->s_hdrwords = hwords;
190 qp->s_cur_size = len;
191 *bth0p = bth0;
192 *bth2p = bth2;
193 return 1;
194
195 bail:
196 return 0;
197 }
198
199 /**
200 * ipath_make_rc_req - construct a request packet (SEND, RDMA r/w, ATOMIC)
201 * @qp: a pointer to the QP
202 * @ohdr: a pointer to the IB header being constructed
203 * @pmtu: the path MTU
204 * @bth0p: pointer to the BTH opcode word
205 * @bth2p: pointer to the BTH PSN word
206 *
207 * Return 1 if constructed; otherwise, return 0.
208 * Note the QP s_lock must be held and interrupts disabled.
209 */
210 int ipath_make_rc_req(struct ipath_qp *qp,
211 struct ipath_other_headers *ohdr,
212 u32 pmtu, u32 *bth0p, u32 *bth2p)
213 {
214 struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
215 struct ipath_sge_state *ss;
216 struct ipath_swqe *wqe;
217 u32 hwords;
218 u32 len;
219 u32 bth0;
220 u32 bth2;
221 char newreq;
222
223 /* Sending responses has higher priority over sending requests. */
224 if ((qp->r_head_ack_queue != qp->s_tail_ack_queue ||
225 (qp->s_flags & IPATH_S_ACK_PENDING) ||
226 qp->s_ack_state != IB_OPCODE_RC_ACKNOWLEDGE) &&
227 ipath_make_rc_ack(qp, ohdr, pmtu, bth0p, bth2p))
228 goto done;
229
230 if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_SEND_OK) ||
231 qp->s_rnr_timeout)
232 goto bail;
233
234 /* Limit the number of packets sent without an ACK. */
235 if (ipath_cmp24(qp->s_psn, qp->s_last_psn + IPATH_PSN_CREDIT) > 0) {
236 qp->s_wait_credit = 1;
237 dev->n_rc_stalls++;
238 spin_lock(&dev->pending_lock);
239 if (list_empty(&qp->timerwait))
240 list_add_tail(&qp->timerwait,
241 &dev->pending[dev->pending_index]);
242 spin_unlock(&dev->pending_lock);
243 goto bail;
244 }
245
246 /* header size in 32-bit words LRH+BTH = (8+12)/4. */
247 hwords = 5;
248 bth0 = 0;
249
250 /* Send a request. */
251 wqe = get_swqe_ptr(qp, qp->s_cur);
252 switch (qp->s_state) {
253 default:
254 /*
255 * Resend an old request or start a new one.
256 *
257 * We keep track of the current SWQE so that
258 * we don't reset the "furthest progress" state
259 * if we need to back up.
260 */
261 newreq = 0;
262 if (qp->s_cur == qp->s_tail) {
263 /* Check if send work queue is empty. */
264 if (qp->s_tail == qp->s_head)
265 goto bail;
266 /*
267 * If a fence is requested, wait for previous
268 * RDMA read and atomic operations to finish.
269 */
270 if ((wqe->wr.send_flags & IB_SEND_FENCE) &&
271 qp->s_num_rd_atomic) {
272 qp->s_flags |= IPATH_S_FENCE_PENDING;
273 goto bail;
274 }
275 wqe->psn = qp->s_next_psn;
276 newreq = 1;
277 }
278 /*
279 * Note that we have to be careful not to modify the
280 * original work request since we may need to resend
281 * it.
282 */
283 len = wqe->length;
284 ss = &qp->s_sge;
285 bth2 = 0;
286 switch (wqe->wr.opcode) {
287 case IB_WR_SEND:
288 case IB_WR_SEND_WITH_IMM:
289 /* If no credit, return. */
290 if (qp->s_lsn != (u32) -1 &&
291 ipath_cmp24(wqe->ssn, qp->s_lsn + 1) > 0)
292 goto bail;
293 wqe->lpsn = wqe->psn;
294 if (len > pmtu) {
295 wqe->lpsn += (len - 1) / pmtu;
296 qp->s_state = OP(SEND_FIRST);
297 len = pmtu;
298 break;
299 }
300 if (wqe->wr.opcode == IB_WR_SEND)
301 qp->s_state = OP(SEND_ONLY);
302 else {
303 qp->s_state = OP(SEND_ONLY_WITH_IMMEDIATE);
304 /* Immediate data comes after the BTH */
305 ohdr->u.imm_data = wqe->wr.imm_data;
306 hwords += 1;
307 }
308 if (wqe->wr.send_flags & IB_SEND_SOLICITED)
309 bth0 |= 1 << 23;
310 bth2 = 1 << 31; /* Request ACK. */
311 if (++qp->s_cur == qp->s_size)
312 qp->s_cur = 0;
313 break;
314
315 case IB_WR_RDMA_WRITE:
316 if (newreq && qp->s_lsn != (u32) -1)
317 qp->s_lsn++;
318 /* FALLTHROUGH */
319 case IB_WR_RDMA_WRITE_WITH_IMM:
320 /* If no credit, return. */
321 if (qp->s_lsn != (u32) -1 &&
322 ipath_cmp24(wqe->ssn, qp->s_lsn + 1) > 0)
323 goto bail;
324 ohdr->u.rc.reth.vaddr =
325 cpu_to_be64(wqe->wr.wr.rdma.remote_addr);
326 ohdr->u.rc.reth.rkey =
327 cpu_to_be32(wqe->wr.wr.rdma.rkey);
328 ohdr->u.rc.reth.length = cpu_to_be32(len);
329 hwords += sizeof(struct ib_reth) / sizeof(u32);
330 wqe->lpsn = wqe->psn;
331 if (len > pmtu) {
332 wqe->lpsn += (len - 1) / pmtu;
333 qp->s_state = OP(RDMA_WRITE_FIRST);
334 len = pmtu;
335 break;
336 }
337 if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
338 qp->s_state = OP(RDMA_WRITE_ONLY);
339 else {
340 qp->s_state =
341 OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE);
342 /* Immediate data comes after RETH */
343 ohdr->u.rc.imm_data = wqe->wr.imm_data;
344 hwords += 1;
345 if (wqe->wr.send_flags & IB_SEND_SOLICITED)
346 bth0 |= 1 << 23;
347 }
348 bth2 = 1 << 31; /* Request ACK. */
349 if (++qp->s_cur == qp->s_size)
350 qp->s_cur = 0;
351 break;
352
353 case IB_WR_RDMA_READ:
354 /*
355 * Don't allow more operations to be started
356 * than the QP limits allow.
357 */
358 if (newreq) {
359 if (qp->s_num_rd_atomic >=
360 qp->s_max_rd_atomic) {
361 qp->s_flags |= IPATH_S_RDMAR_PENDING;
362 goto bail;
363 }
364 qp->s_num_rd_atomic++;
365 if (qp->s_lsn != (u32) -1)
366 qp->s_lsn++;
367 /*
368 * Adjust s_next_psn to count the
369 * expected number of responses.
370 */
371 if (len > pmtu)
372 qp->s_next_psn += (len - 1) / pmtu;
373 wqe->lpsn = qp->s_next_psn++;
374 }
375 ohdr->u.rc.reth.vaddr =
376 cpu_to_be64(wqe->wr.wr.rdma.remote_addr);
377 ohdr->u.rc.reth.rkey =
378 cpu_to_be32(wqe->wr.wr.rdma.rkey);
379 ohdr->u.rc.reth.length = cpu_to_be32(len);
380 qp->s_state = OP(RDMA_READ_REQUEST);
381 hwords += sizeof(ohdr->u.rc.reth) / sizeof(u32);
382 ss = NULL;
383 len = 0;
384 if (++qp->s_cur == qp->s_size)
385 qp->s_cur = 0;
386 break;
387
388 case IB_WR_ATOMIC_CMP_AND_SWP:
389 case IB_WR_ATOMIC_FETCH_AND_ADD:
390 /*
391 * Don't allow more operations to be started
392 * than the QP limits allow.
393 */
394 if (newreq) {
395 if (qp->s_num_rd_atomic >=
396 qp->s_max_rd_atomic) {
397 qp->s_flags |= IPATH_S_RDMAR_PENDING;
398 goto bail;
399 }
400 qp->s_num_rd_atomic++;
401 if (qp->s_lsn != (u32) -1)
402 qp->s_lsn++;
403 wqe->lpsn = wqe->psn;
404 }
405 if (wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP) {
406 qp->s_state = OP(COMPARE_SWAP);
407 ohdr->u.atomic_eth.swap_data = cpu_to_be64(
408 wqe->wr.wr.atomic.swap);
409 ohdr->u.atomic_eth.compare_data = cpu_to_be64(
410 wqe->wr.wr.atomic.compare_add);
411 } else {
412 qp->s_state = OP(FETCH_ADD);
413 ohdr->u.atomic_eth.swap_data = cpu_to_be64(
414 wqe->wr.wr.atomic.compare_add);
415 ohdr->u.atomic_eth.compare_data = 0;
416 }
417 ohdr->u.atomic_eth.vaddr[0] = cpu_to_be32(
418 wqe->wr.wr.atomic.remote_addr >> 32);
419 ohdr->u.atomic_eth.vaddr[1] = cpu_to_be32(
420 wqe->wr.wr.atomic.remote_addr);
421 ohdr->u.atomic_eth.rkey = cpu_to_be32(
422 wqe->wr.wr.atomic.rkey);
423 hwords += sizeof(struct ib_atomic_eth) / sizeof(u32);
424 ss = NULL;
425 len = 0;
426 if (++qp->s_cur == qp->s_size)
427 qp->s_cur = 0;
428 break;
429
430 default:
431 goto bail;
432 }
433 qp->s_sge.sge = wqe->sg_list[0];
434 qp->s_sge.sg_list = wqe->sg_list + 1;
435 qp->s_sge.num_sge = wqe->wr.num_sge;
436 qp->s_len = wqe->length;
437 if (newreq) {
438 qp->s_tail++;
439 if (qp->s_tail >= qp->s_size)
440 qp->s_tail = 0;
441 }
442 bth2 |= qp->s_psn & IPATH_PSN_MASK;
443 if (wqe->wr.opcode == IB_WR_RDMA_READ)
444 qp->s_psn = wqe->lpsn + 1;
445 else {
446 qp->s_psn++;
447 if (ipath_cmp24(qp->s_psn, qp->s_next_psn) > 0)
448 qp->s_next_psn = qp->s_psn;
449 }
450 /*
451 * Put the QP on the pending list so lost ACKs will cause
452 * a retry. More than one request can be pending so the
453 * QP may already be on the dev->pending list.
454 */
455 spin_lock(&dev->pending_lock);
456 if (list_empty(&qp->timerwait))
457 list_add_tail(&qp->timerwait,
458 &dev->pending[dev->pending_index]);
459 spin_unlock(&dev->pending_lock);
460 break;
461
462 case OP(RDMA_READ_RESPONSE_FIRST):
463 /*
464 * This case can only happen if a send is restarted.
465 * See ipath_restart_rc().
466 */
467 ipath_init_restart(qp, wqe);
468 /* FALLTHROUGH */
469 case OP(SEND_FIRST):
470 qp->s_state = OP(SEND_MIDDLE);
471 /* FALLTHROUGH */
472 case OP(SEND_MIDDLE):
473 bth2 = qp->s_psn++ & IPATH_PSN_MASK;
474 if (ipath_cmp24(qp->s_psn, qp->s_next_psn) > 0)
475 qp->s_next_psn = qp->s_psn;
476 ss = &qp->s_sge;
477 len = qp->s_len;
478 if (len > pmtu) {
479 len = pmtu;
480 break;
481 }
482 if (wqe->wr.opcode == IB_WR_SEND)
483 qp->s_state = OP(SEND_LAST);
484 else {
485 qp->s_state = OP(SEND_LAST_WITH_IMMEDIATE);
486 /* Immediate data comes after the BTH */
487 ohdr->u.imm_data = wqe->wr.imm_data;
488 hwords += 1;
489 }
490 if (wqe->wr.send_flags & IB_SEND_SOLICITED)
491 bth0 |= 1 << 23;
492 bth2 |= 1 << 31; /* Request ACK. */
493 qp->s_cur++;
494 if (qp->s_cur >= qp->s_size)
495 qp->s_cur = 0;
496 break;
497
498 case OP(RDMA_READ_RESPONSE_LAST):
499 /*
500 * This case can only happen if a RDMA write is restarted.
501 * See ipath_restart_rc().
502 */
503 ipath_init_restart(qp, wqe);
504 /* FALLTHROUGH */
505 case OP(RDMA_WRITE_FIRST):
506 qp->s_state = OP(RDMA_WRITE_MIDDLE);
507 /* FALLTHROUGH */
508 case OP(RDMA_WRITE_MIDDLE):
509 bth2 = qp->s_psn++ & IPATH_PSN_MASK;
510 if (ipath_cmp24(qp->s_psn, qp->s_next_psn) > 0)
511 qp->s_next_psn = qp->s_psn;
512 ss = &qp->s_sge;
513 len = qp->s_len;
514 if (len > pmtu) {
515 len = pmtu;
516 break;
517 }
518 if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
519 qp->s_state = OP(RDMA_WRITE_LAST);
520 else {
521 qp->s_state = OP(RDMA_WRITE_LAST_WITH_IMMEDIATE);
522 /* Immediate data comes after the BTH */
523 ohdr->u.imm_data = wqe->wr.imm_data;
524 hwords += 1;
525 if (wqe->wr.send_flags & IB_SEND_SOLICITED)
526 bth0 |= 1 << 23;
527 }
528 bth2 |= 1 << 31; /* Request ACK. */
529 qp->s_cur++;
530 if (qp->s_cur >= qp->s_size)
531 qp->s_cur = 0;
532 break;
533
534 case OP(RDMA_READ_RESPONSE_MIDDLE):
535 /*
536 * This case can only happen if a RDMA read is restarted.
537 * See ipath_restart_rc().
538 */
539 ipath_init_restart(qp, wqe);
540 len = ((qp->s_psn - wqe->psn) & IPATH_PSN_MASK) * pmtu;
541 ohdr->u.rc.reth.vaddr =
542 cpu_to_be64(wqe->wr.wr.rdma.remote_addr + len);
543 ohdr->u.rc.reth.rkey =
544 cpu_to_be32(wqe->wr.wr.rdma.rkey);
545 ohdr->u.rc.reth.length = cpu_to_be32(qp->s_len);
546 qp->s_state = OP(RDMA_READ_REQUEST);
547 hwords += sizeof(ohdr->u.rc.reth) / sizeof(u32);
548 bth2 = qp->s_psn++ & IPATH_PSN_MASK;
549 if (ipath_cmp24(qp->s_psn, qp->s_next_psn) > 0)
550 qp->s_next_psn = qp->s_psn;
551 ss = NULL;
552 len = 0;
553 qp->s_cur++;
554 if (qp->s_cur == qp->s_size)
555 qp->s_cur = 0;
556 break;
557 }
558 if (ipath_cmp24(qp->s_psn, qp->s_last_psn + IPATH_PSN_CREDIT - 1) >= 0)
559 bth2 |= 1 << 31; /* Request ACK. */
560 qp->s_len -= len;
561 qp->s_hdrwords = hwords;
562 qp->s_cur_sge = ss;
563 qp->s_cur_size = len;
564 *bth0p = bth0 | (qp->s_state << 24);
565 *bth2p = bth2;
566 done:
567 return 1;
568
569 bail:
570 return 0;
571 }
572
573 /**
574 * send_rc_ack - Construct an ACK packet and send it
575 * @qp: a pointer to the QP
576 *
577 * This is called from ipath_rc_rcv() and only uses the receive
578 * side QP state.
579 * Note that RDMA reads and atomics are handled in the
580 * send side QP state and tasklet.
581 */
582 static void send_rc_ack(struct ipath_qp *qp)
583 {
584 struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
585 u16 lrh0;
586 u32 bth0;
587 u32 hwords;
588 struct ipath_ib_header hdr;
589 struct ipath_other_headers *ohdr;
590
591 /* Don't send ACK or NAK if a RDMA read or atomic is pending. */
592 if (qp->r_head_ack_queue != qp->s_tail_ack_queue)
593 goto queue_ack;
594
595 /* Construct the header. */
596 ohdr = &hdr.u.oth;
597 lrh0 = IPATH_LRH_BTH;
598 /* header size in 32-bit words LRH+BTH+AETH = (8+12+4)/4. */
599 hwords = 6;
600 if (unlikely(qp->remote_ah_attr.ah_flags & IB_AH_GRH)) {
601 hwords += ipath_make_grh(dev, &hdr.u.l.grh,
602 &qp->remote_ah_attr.grh,
603 hwords, 0);
604 ohdr = &hdr.u.l.oth;
605 lrh0 = IPATH_LRH_GRH;
606 }
607 /* read pkey_index w/o lock (its atomic) */
608 bth0 = ipath_get_pkey(dev->dd, qp->s_pkey_index) |
609 OP(ACKNOWLEDGE) << 24;
610 if (qp->r_nak_state)
611 ohdr->u.aeth = cpu_to_be32((qp->r_msn & IPATH_MSN_MASK) |
612 (qp->r_nak_state <<
613 IPATH_AETH_CREDIT_SHIFT));
614 else
615 ohdr->u.aeth = ipath_compute_aeth(qp);
616 lrh0 |= qp->remote_ah_attr.sl << 4;
617 hdr.lrh[0] = cpu_to_be16(lrh0);
618 hdr.lrh[1] = cpu_to_be16(qp->remote_ah_attr.dlid);
619 hdr.lrh[2] = cpu_to_be16(hwords + SIZE_OF_CRC);
620 hdr.lrh[3] = cpu_to_be16(dev->dd->ipath_lid);
621 ohdr->bth[0] = cpu_to_be32(bth0);
622 ohdr->bth[1] = cpu_to_be32(qp->remote_qpn);
623 ohdr->bth[2] = cpu_to_be32(qp->r_ack_psn & IPATH_PSN_MASK);
624
625 /*
626 * If we can send the ACK, clear the ACK state.
627 */
628 if (ipath_verbs_send(dev->dd, hwords, (u32 *) &hdr, 0, NULL) == 0) {
629 dev->n_unicast_xmit++;
630 goto done;
631 }
632
633 /*
634 * We are out of PIO buffers at the moment.
635 * Pass responsibility for sending the ACK to the
636 * send tasklet so that when a PIO buffer becomes
637 * available, the ACK is sent ahead of other outgoing
638 * packets.
639 */
640 dev->n_rc_qacks++;
641
642 queue_ack:
643 spin_lock_irq(&qp->s_lock);
644 qp->s_flags |= IPATH_S_ACK_PENDING;
645 qp->s_nak_state = qp->r_nak_state;
646 qp->s_ack_psn = qp->r_ack_psn;
647 spin_unlock_irq(&qp->s_lock);
648
649 /* Call ipath_do_rc_send() in another thread. */
650 tasklet_hi_schedule(&qp->s_task);
651
652 done:
653 return;
654 }
655
656 /**
657 * reset_psn - reset the QP state to send starting from PSN
658 * @qp: the QP
659 * @psn: the packet sequence number to restart at
660 *
661 * This is called from ipath_rc_rcv() to process an incoming RC ACK
662 * for the given QP.
663 * Called at interrupt level with the QP s_lock held.
664 */
665 static void reset_psn(struct ipath_qp *qp, u32 psn)
666 {
667 u32 n = qp->s_last;
668 struct ipath_swqe *wqe = get_swqe_ptr(qp, n);
669 u32 opcode;
670
671 qp->s_cur = n;
672
673 /*
674 * If we are starting the request from the beginning,
675 * let the normal send code handle initialization.
676 */
677 if (ipath_cmp24(psn, wqe->psn) <= 0) {
678 qp->s_state = OP(SEND_LAST);
679 goto done;
680 }
681
682 /* Find the work request opcode corresponding to the given PSN. */
683 opcode = wqe->wr.opcode;
684 for (;;) {
685 int diff;
686
687 if (++n == qp->s_size)
688 n = 0;
689 if (n == qp->s_tail)
690 break;
691 wqe = get_swqe_ptr(qp, n);
692 diff = ipath_cmp24(psn, wqe->psn);
693 if (diff < 0)
694 break;
695 qp->s_cur = n;
696 /*
697 * If we are starting the request from the beginning,
698 * let the normal send code handle initialization.
699 */
700 if (diff == 0) {
701 qp->s_state = OP(SEND_LAST);
702 goto done;
703 }
704 opcode = wqe->wr.opcode;
705 }
706
707 /*
708 * Set the state to restart in the middle of a request.
709 * Don't change the s_sge, s_cur_sge, or s_cur_size.
710 * See ipath_do_rc_send().
711 */
712 switch (opcode) {
713 case IB_WR_SEND:
714 case IB_WR_SEND_WITH_IMM:
715 qp->s_state = OP(RDMA_READ_RESPONSE_FIRST);
716 break;
717
718 case IB_WR_RDMA_WRITE:
719 case IB_WR_RDMA_WRITE_WITH_IMM:
720 qp->s_state = OP(RDMA_READ_RESPONSE_LAST);
721 break;
722
723 case IB_WR_RDMA_READ:
724 qp->s_state = OP(RDMA_READ_RESPONSE_MIDDLE);
725 break;
726
727 default:
728 /*
729 * This case shouldn't happen since its only
730 * one PSN per req.
731 */
732 qp->s_state = OP(SEND_LAST);
733 }
734 done:
735 qp->s_psn = psn;
736 }
737
738 /**
739 * ipath_restart_rc - back up requester to resend the last un-ACKed request
740 * @qp: the QP to restart
741 * @psn: packet sequence number for the request
742 * @wc: the work completion request
743 *
744 * The QP s_lock should be held and interrupts disabled.
745 */
746 void ipath_restart_rc(struct ipath_qp *qp, u32 psn, struct ib_wc *wc)
747 {
748 struct ipath_swqe *wqe = get_swqe_ptr(qp, qp->s_last);
749 struct ipath_ibdev *dev;
750
751 if (qp->s_retry == 0) {
752 wc->wr_id = wqe->wr.wr_id;
753 wc->status = IB_WC_RETRY_EXC_ERR;
754 wc->opcode = ib_ipath_wc_opcode[wqe->wr.opcode];
755 wc->vendor_err = 0;
756 wc->byte_len = 0;
757 wc->qp = &qp->ibqp;
758 wc->src_qp = qp->remote_qpn;
759 wc->pkey_index = 0;
760 wc->slid = qp->remote_ah_attr.dlid;
761 wc->sl = qp->remote_ah_attr.sl;
762 wc->dlid_path_bits = 0;
763 wc->port_num = 0;
764 ipath_sqerror_qp(qp, wc);
765 goto bail;
766 }
767 qp->s_retry--;
768
769 /*
770 * Remove the QP from the timeout queue.
771 * Note: it may already have been removed by ipath_ib_timer().
772 */
773 dev = to_idev(qp->ibqp.device);
774 spin_lock(&dev->pending_lock);
775 if (!list_empty(&qp->timerwait))
776 list_del_init(&qp->timerwait);
777 spin_unlock(&dev->pending_lock);
778
779 if (wqe->wr.opcode == IB_WR_RDMA_READ)
780 dev->n_rc_resends++;
781 else
782 dev->n_rc_resends += (qp->s_psn - psn) & IPATH_PSN_MASK;
783
784 reset_psn(qp, psn);
785 tasklet_hi_schedule(&qp->s_task);
786
787 bail:
788 return;
789 }
790
791 static inline void update_last_psn(struct ipath_qp *qp, u32 psn)
792 {
793 if (qp->s_wait_credit) {
794 qp->s_wait_credit = 0;
795 tasklet_hi_schedule(&qp->s_task);
796 }
797 qp->s_last_psn = psn;
798 }
799
800 /**
801 * do_rc_ack - process an incoming RC ACK
802 * @qp: the QP the ACK came in on
803 * @psn: the packet sequence number of the ACK
804 * @opcode: the opcode of the request that resulted in the ACK
805 *
806 * This is called from ipath_rc_rcv_resp() to process an incoming RC ACK
807 * for the given QP.
808 * Called at interrupt level with the QP s_lock held and interrupts disabled.
809 * Returns 1 if OK, 0 if current operation should be aborted (NAK).
810 */
811 static int do_rc_ack(struct ipath_qp *qp, u32 aeth, u32 psn, int opcode)
812 {
813 struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
814 struct ib_wc wc;
815 struct ipath_swqe *wqe;
816 int ret = 0;
817 u32 ack_psn;
818
819 /*
820 * Remove the QP from the timeout queue (or RNR timeout queue).
821 * If ipath_ib_timer() has already removed it,
822 * it's OK since we hold the QP s_lock and ipath_restart_rc()
823 * just won't find anything to restart if we ACK everything.
824 */
825 spin_lock(&dev->pending_lock);
826 if (!list_empty(&qp->timerwait))
827 list_del_init(&qp->timerwait);
828 spin_unlock(&dev->pending_lock);
829
830 /*
831 * Note that NAKs implicitly ACK outstanding SEND and RDMA write
832 * requests and implicitly NAK RDMA read and atomic requests issued
833 * before the NAK'ed request. The MSN won't include the NAK'ed
834 * request but will include an ACK'ed request(s).
835 */
836 ack_psn = psn;
837 if (aeth >> 29)
838 ack_psn--;
839 wqe = get_swqe_ptr(qp, qp->s_last);
840
841 /*
842 * The MSN might be for a later WQE than the PSN indicates so
843 * only complete WQEs that the PSN finishes.
844 */
845 while (ipath_cmp24(ack_psn, wqe->lpsn) >= 0) {
846 /*
847 * If this request is a RDMA read or atomic, and the ACK is
848 * for a later operation, this ACK NAKs the RDMA read or
849 * atomic. In other words, only a RDMA_READ_LAST or ONLY
850 * can ACK a RDMA read and likewise for atomic ops. Note
851 * that the NAK case can only happen if relaxed ordering is
852 * used and requests are sent after an RDMA read or atomic
853 * is sent but before the response is received.
854 */
855 if ((wqe->wr.opcode == IB_WR_RDMA_READ &&
856 (opcode != OP(RDMA_READ_RESPONSE_LAST) ||
857 ipath_cmp24(ack_psn, wqe->lpsn) != 0)) ||
858 ((wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
859 wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) &&
860 (opcode != OP(ATOMIC_ACKNOWLEDGE) ||
861 ipath_cmp24(wqe->psn, psn) != 0))) {
862 /*
863 * The last valid PSN seen is the previous
864 * request's.
865 */
866 update_last_psn(qp, wqe->psn - 1);
867 /* Retry this request. */
868 ipath_restart_rc(qp, wqe->psn, &wc);
869 /*
870 * No need to process the ACK/NAK since we are
871 * restarting an earlier request.
872 */
873 goto bail;
874 }
875 if (qp->s_num_rd_atomic &&
876 (wqe->wr.opcode == IB_WR_RDMA_READ ||
877 wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
878 wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)) {
879 qp->s_num_rd_atomic--;
880 /* Restart sending task if fence is complete */
881 if ((qp->s_flags & IPATH_S_FENCE_PENDING) &&
882 !qp->s_num_rd_atomic) {
883 qp->s_flags &= ~IPATH_S_FENCE_PENDING;
884 tasklet_hi_schedule(&qp->s_task);
885 } else if (qp->s_flags & IPATH_S_RDMAR_PENDING) {
886 qp->s_flags &= ~IPATH_S_RDMAR_PENDING;
887 tasklet_hi_schedule(&qp->s_task);
888 }
889 }
890 /* Post a send completion queue entry if requested. */
891 if (!(qp->s_flags & IPATH_S_SIGNAL_REQ_WR) ||
892 (wqe->wr.send_flags & IB_SEND_SIGNALED)) {
893 wc.wr_id = wqe->wr.wr_id;
894 wc.status = IB_WC_SUCCESS;
895 wc.opcode = ib_ipath_wc_opcode[wqe->wr.opcode];
896 wc.vendor_err = 0;
897 wc.byte_len = wqe->length;
898 wc.imm_data = 0;
899 wc.qp = &qp->ibqp;
900 wc.src_qp = qp->remote_qpn;
901 wc.wc_flags = 0;
902 wc.pkey_index = 0;
903 wc.slid = qp->remote_ah_attr.dlid;
904 wc.sl = qp->remote_ah_attr.sl;
905 wc.dlid_path_bits = 0;
906 wc.port_num = 0;
907 ipath_cq_enter(to_icq(qp->ibqp.send_cq), &wc, 0);
908 }
909 qp->s_retry = qp->s_retry_cnt;
910 /*
911 * If we are completing a request which is in the process of
912 * being resent, we can stop resending it since we know the
913 * responder has already seen it.
914 */
915 if (qp->s_last == qp->s_cur) {
916 if (++qp->s_cur >= qp->s_size)
917 qp->s_cur = 0;
918 qp->s_last = qp->s_cur;
919 if (qp->s_last == qp->s_tail)
920 break;
921 wqe = get_swqe_ptr(qp, qp->s_cur);
922 qp->s_state = OP(SEND_LAST);
923 qp->s_psn = wqe->psn;
924 } else {
925 if (++qp->s_last >= qp->s_size)
926 qp->s_last = 0;
927 if (qp->s_last == qp->s_tail)
928 break;
929 wqe = get_swqe_ptr(qp, qp->s_last);
930 }
931 }
932
933 switch (aeth >> 29) {
934 case 0: /* ACK */
935 dev->n_rc_acks++;
936 /* If this is a partial ACK, reset the retransmit timer. */
937 if (qp->s_last != qp->s_tail) {
938 spin_lock(&dev->pending_lock);
939 list_add_tail(&qp->timerwait,
940 &dev->pending[dev->pending_index]);
941 spin_unlock(&dev->pending_lock);
942 /*
943 * If we get a partial ACK for a resent operation,
944 * we can stop resending the earlier packets and
945 * continue with the next packet the receiver wants.
946 */
947 if (ipath_cmp24(qp->s_psn, psn) <= 0) {
948 reset_psn(qp, psn + 1);
949 tasklet_hi_schedule(&qp->s_task);
950 }
951 } else if (ipath_cmp24(qp->s_psn, psn) <= 0) {
952 qp->s_state = OP(SEND_LAST);
953 qp->s_psn = psn + 1;
954 }
955 ipath_get_credit(qp, aeth);
956 qp->s_rnr_retry = qp->s_rnr_retry_cnt;
957 qp->s_retry = qp->s_retry_cnt;
958 update_last_psn(qp, psn);
959 ret = 1;
960 goto bail;
961
962 case 1: /* RNR NAK */
963 dev->n_rnr_naks++;
964 if (qp->s_last == qp->s_tail)
965 goto bail;
966 if (qp->s_rnr_retry == 0) {
967 wc.status = IB_WC_RNR_RETRY_EXC_ERR;
968 goto class_b;
969 }
970 if (qp->s_rnr_retry_cnt < 7)
971 qp->s_rnr_retry--;
972
973 /* The last valid PSN is the previous PSN. */
974 update_last_psn(qp, psn - 1);
975
976 if (wqe->wr.opcode == IB_WR_RDMA_READ)
977 dev->n_rc_resends++;
978 else
979 dev->n_rc_resends +=
980 (qp->s_psn - psn) & IPATH_PSN_MASK;
981
982 reset_psn(qp, psn);
983
984 qp->s_rnr_timeout =
985 ib_ipath_rnr_table[(aeth >> IPATH_AETH_CREDIT_SHIFT) &
986 IPATH_AETH_CREDIT_MASK];
987 ipath_insert_rnr_queue(qp);
988 goto bail;
989
990 case 3: /* NAK */
991 if (qp->s_last == qp->s_tail)
992 goto bail;
993 /* The last valid PSN is the previous PSN. */
994 update_last_psn(qp, psn - 1);
995 switch ((aeth >> IPATH_AETH_CREDIT_SHIFT) &
996 IPATH_AETH_CREDIT_MASK) {
997 case 0: /* PSN sequence error */
998 dev->n_seq_naks++;
999 /*
1000 * Back up to the responder's expected PSN.
1001 * Note that we might get a NAK in the middle of an
1002 * RDMA READ response which terminates the RDMA
1003 * READ.
1004 */
1005 ipath_restart_rc(qp, psn, &wc);
1006 break;
1007
1008 case 1: /* Invalid Request */
1009 wc.status = IB_WC_REM_INV_REQ_ERR;
1010 dev->n_other_naks++;
1011 goto class_b;
1012
1013 case 2: /* Remote Access Error */
1014 wc.status = IB_WC_REM_ACCESS_ERR;
1015 dev->n_other_naks++;
1016 goto class_b;
1017
1018 case 3: /* Remote Operation Error */
1019 wc.status = IB_WC_REM_OP_ERR;
1020 dev->n_other_naks++;
1021 class_b:
1022 wc.wr_id = wqe->wr.wr_id;
1023 wc.opcode = ib_ipath_wc_opcode[wqe->wr.opcode];
1024 wc.vendor_err = 0;
1025 wc.byte_len = 0;
1026 wc.qp = &qp->ibqp;
1027 wc.src_qp = qp->remote_qpn;
1028 wc.pkey_index = 0;
1029 wc.slid = qp->remote_ah_attr.dlid;
1030 wc.sl = qp->remote_ah_attr.sl;
1031 wc.dlid_path_bits = 0;
1032 wc.port_num = 0;
1033 ipath_sqerror_qp(qp, &wc);
1034 break;
1035
1036 default:
1037 /* Ignore other reserved NAK error codes */
1038 goto reserved;
1039 }
1040 qp->s_rnr_retry = qp->s_rnr_retry_cnt;
1041 goto bail;
1042
1043 default: /* 2: reserved */
1044 reserved:
1045 /* Ignore reserved NAK codes. */
1046 goto bail;
1047 }
1048
1049 bail:
1050 return ret;
1051 }
1052
1053 /**
1054 * ipath_rc_rcv_resp - process an incoming RC response packet
1055 * @dev: the device this packet came in on
1056 * @ohdr: the other headers for this packet
1057 * @data: the packet data
1058 * @tlen: the packet length
1059 * @qp: the QP for this packet
1060 * @opcode: the opcode for this packet
1061 * @psn: the packet sequence number for this packet
1062 * @hdrsize: the header length
1063 * @pmtu: the path MTU
1064 * @header_in_data: true if part of the header data is in the data buffer
1065 *
1066 * This is called from ipath_rc_rcv() to process an incoming RC response
1067 * packet for the given QP.
1068 * Called at interrupt level.
1069 */
1070 static inline void ipath_rc_rcv_resp(struct ipath_ibdev *dev,
1071 struct ipath_other_headers *ohdr,
1072 void *data, u32 tlen,
1073 struct ipath_qp *qp,
1074 u32 opcode,
1075 u32 psn, u32 hdrsize, u32 pmtu,
1076 int header_in_data)
1077 {
1078 struct ipath_swqe *wqe;
1079 unsigned long flags;
1080 struct ib_wc wc;
1081 int diff;
1082 u32 pad;
1083 u32 aeth;
1084
1085 spin_lock_irqsave(&qp->s_lock, flags);
1086
1087 /* Ignore invalid responses. */
1088 if (ipath_cmp24(psn, qp->s_next_psn) >= 0)
1089 goto ack_done;
1090
1091 /* Ignore duplicate responses. */
1092 diff = ipath_cmp24(psn, qp->s_last_psn);
1093 if (unlikely(diff <= 0)) {
1094 /* Update credits for "ghost" ACKs */
1095 if (diff == 0 && opcode == OP(ACKNOWLEDGE)) {
1096 if (!header_in_data)
1097 aeth = be32_to_cpu(ohdr->u.aeth);
1098 else {
1099 aeth = be32_to_cpu(((__be32 *) data)[0]);
1100 data += sizeof(__be32);
1101 }
1102 if ((aeth >> 29) == 0)
1103 ipath_get_credit(qp, aeth);
1104 }
1105 goto ack_done;
1106 }
1107
1108 if (unlikely(qp->s_last == qp->s_tail))
1109 goto ack_done;
1110 wqe = get_swqe_ptr(qp, qp->s_last);
1111
1112 switch (opcode) {
1113 case OP(ACKNOWLEDGE):
1114 case OP(ATOMIC_ACKNOWLEDGE):
1115 case OP(RDMA_READ_RESPONSE_FIRST):
1116 if (!header_in_data)
1117 aeth = be32_to_cpu(ohdr->u.aeth);
1118 else {
1119 aeth = be32_to_cpu(((__be32 *) data)[0]);
1120 data += sizeof(__be32);
1121 }
1122 if (opcode == OP(ATOMIC_ACKNOWLEDGE)) {
1123 u64 val;
1124
1125 if (!header_in_data) {
1126 __be32 *p = ohdr->u.at.atomic_ack_eth;
1127
1128 val = ((u64) be32_to_cpu(p[0]) << 32) |
1129 be32_to_cpu(p[1]);
1130 } else
1131 val = be64_to_cpu(((__be64 *) data)[0]);
1132 *(u64 *) wqe->sg_list[0].vaddr = val;
1133 }
1134 if (!do_rc_ack(qp, aeth, psn, opcode) ||
1135 opcode != OP(RDMA_READ_RESPONSE_FIRST))
1136 goto ack_done;
1137 hdrsize += 4;
1138 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1139 goto ack_done;
1140 /*
1141 * If this is a response to a resent RDMA read, we
1142 * have to be careful to copy the data to the right
1143 * location.
1144 */
1145 qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
1146 wqe, psn, pmtu);
1147 goto read_middle;
1148
1149 case OP(RDMA_READ_RESPONSE_MIDDLE):
1150 /* no AETH, no ACK */
1151 if (unlikely(ipath_cmp24(psn, qp->s_last_psn + 1))) {
1152 dev->n_rdma_seq++;
1153 ipath_restart_rc(qp, qp->s_last_psn + 1, &wc);
1154 goto ack_done;
1155 }
1156 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1157 goto ack_done;
1158 read_middle:
1159 if (unlikely(tlen != (hdrsize + pmtu + 4)))
1160 goto ack_done;
1161 if (unlikely(pmtu >= qp->s_rdma_read_len))
1162 goto ack_done;
1163
1164 /* We got a response so update the timeout. */
1165 spin_lock(&dev->pending_lock);
1166 if (qp->s_rnr_timeout == 0 && !list_empty(&qp->timerwait))
1167 list_move_tail(&qp->timerwait,
1168 &dev->pending[dev->pending_index]);
1169 spin_unlock(&dev->pending_lock);
1170 /*
1171 * Update the RDMA receive state but do the copy w/o
1172 * holding the locks and blocking interrupts.
1173 */
1174 qp->s_rdma_read_len -= pmtu;
1175 update_last_psn(qp, psn);
1176 spin_unlock_irqrestore(&qp->s_lock, flags);
1177 ipath_copy_sge(&qp->s_rdma_read_sge, data, pmtu);
1178 goto bail;
1179
1180 case OP(RDMA_READ_RESPONSE_ONLY):
1181 if (unlikely(ipath_cmp24(psn, qp->s_last_psn + 1))) {
1182 dev->n_rdma_seq++;
1183 ipath_restart_rc(qp, qp->s_last_psn + 1, &wc);
1184 goto ack_done;
1185 }
1186 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1187 goto ack_done;
1188 /*
1189 * If this is a response to a resent RDMA read, we
1190 * have to be careful to copy the data to the right
1191 * location.
1192 * XXX should check PSN and wqe opcode first.
1193 */
1194 qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
1195 wqe, psn, pmtu);
1196 goto read_last;
1197
1198 case OP(RDMA_READ_RESPONSE_LAST):
1199 /* ACKs READ req. */
1200 if (unlikely(ipath_cmp24(psn, qp->s_last_psn + 1))) {
1201 dev->n_rdma_seq++;
1202 ipath_restart_rc(qp, qp->s_last_psn + 1, &wc);
1203 goto ack_done;
1204 }
1205 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1206 goto ack_done;
1207 read_last:
1208 /*
1209 * Get the number of bytes the message was padded by.
1210 */
1211 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1212 /*
1213 * Check that the data size is >= 1 && <= pmtu.
1214 * Remember to account for the AETH header (4) and
1215 * ICRC (4).
1216 */
1217 if (unlikely(tlen <= (hdrsize + pad + 8))) {
1218 /* XXX Need to generate an error CQ entry. */
1219 goto ack_done;
1220 }
1221 tlen -= hdrsize + pad + 8;
1222 if (unlikely(tlen != qp->s_rdma_read_len)) {
1223 /* XXX Need to generate an error CQ entry. */
1224 goto ack_done;
1225 }
1226 if (!header_in_data)
1227 aeth = be32_to_cpu(ohdr->u.aeth);
1228 else {
1229 aeth = be32_to_cpu(((__be32 *) data)[0]);
1230 data += sizeof(__be32);
1231 }
1232 ipath_copy_sge(&qp->s_rdma_read_sge, data, tlen);
1233 (void) do_rc_ack(qp, aeth, psn, OP(RDMA_READ_RESPONSE_LAST));
1234 goto ack_done;
1235 }
1236
1237 ack_done:
1238 spin_unlock_irqrestore(&qp->s_lock, flags);
1239 bail:
1240 return;
1241 }
1242
1243 /**
1244 * ipath_rc_rcv_error - process an incoming duplicate or error RC packet
1245 * @dev: the device this packet came in on
1246 * @ohdr: the other headers for this packet
1247 * @data: the packet data
1248 * @qp: the QP for this packet
1249 * @opcode: the opcode for this packet
1250 * @psn: the packet sequence number for this packet
1251 * @diff: the difference between the PSN and the expected PSN
1252 * @header_in_data: true if part of the header data is in the data buffer
1253 *
1254 * This is called from ipath_rc_rcv() to process an unexpected
1255 * incoming RC packet for the given QP.
1256 * Called at interrupt level.
1257 * Return 1 if no more processing is needed; otherwise return 0 to
1258 * schedule a response to be sent.
1259 */
1260 static inline int ipath_rc_rcv_error(struct ipath_ibdev *dev,
1261 struct ipath_other_headers *ohdr,
1262 void *data,
1263 struct ipath_qp *qp,
1264 u32 opcode,
1265 u32 psn,
1266 int diff,
1267 int header_in_data)
1268 {
1269 struct ipath_ack_entry *e;
1270 u8 i, prev;
1271 int old_req;
1272
1273 if (diff > 0) {
1274 /*
1275 * Packet sequence error.
1276 * A NAK will ACK earlier sends and RDMA writes.
1277 * Don't queue the NAK if we already sent one.
1278 */
1279 if (!qp->r_nak_state) {
1280 qp->r_nak_state = IB_NAK_PSN_ERROR;
1281 /* Use the expected PSN. */
1282 qp->r_ack_psn = qp->r_psn;
1283 goto send_ack;
1284 }
1285 goto done;
1286 }
1287
1288 /*
1289 * Handle a duplicate request. Don't re-execute SEND, RDMA
1290 * write or atomic op. Don't NAK errors, just silently drop
1291 * the duplicate request. Note that r_sge, r_len, and
1292 * r_rcv_len may be in use so don't modify them.
1293 *
1294 * We are supposed to ACK the earliest duplicate PSN but we
1295 * can coalesce an outstanding duplicate ACK. We have to
1296 * send the earliest so that RDMA reads can be restarted at
1297 * the requester's expected PSN.
1298 *
1299 * First, find where this duplicate PSN falls within the
1300 * ACKs previously sent.
1301 */
1302 psn &= IPATH_PSN_MASK;
1303 e = NULL;
1304 old_req = 1;
1305 spin_lock_irq(&qp->s_lock);
1306 for (i = qp->r_head_ack_queue; ; i = prev) {
1307 if (i == qp->s_tail_ack_queue)
1308 old_req = 0;
1309 if (i)
1310 prev = i - 1;
1311 else
1312 prev = IPATH_MAX_RDMA_ATOMIC;
1313 if (prev == qp->r_head_ack_queue) {
1314 e = NULL;
1315 break;
1316 }
1317 e = &qp->s_ack_queue[prev];
1318 if (!e->opcode) {
1319 e = NULL;
1320 break;
1321 }
1322 if (ipath_cmp24(psn, e->psn) >= 0)
1323 break;
1324 }
1325 switch (opcode) {
1326 case OP(RDMA_READ_REQUEST): {
1327 struct ib_reth *reth;
1328 u32 offset;
1329 u32 len;
1330
1331 /*
1332 * If we didn't find the RDMA read request in the ack queue,
1333 * or the send tasklet is already backed up to send an
1334 * earlier entry, we can ignore this request.
1335 */
1336 if (!e || e->opcode != OP(RDMA_READ_REQUEST) || old_req)
1337 goto unlock_done;
1338 /* RETH comes after BTH */
1339 if (!header_in_data)
1340 reth = &ohdr->u.rc.reth;
1341 else {
1342 reth = (struct ib_reth *)data;
1343 data += sizeof(*reth);
1344 }
1345 /*
1346 * Address range must be a subset of the original
1347 * request and start on pmtu boundaries.
1348 * We reuse the old ack_queue slot since the requester
1349 * should not back up and request an earlier PSN for the
1350 * same request.
1351 */
1352 offset = ((psn - e->psn) & IPATH_PSN_MASK) *
1353 ib_mtu_enum_to_int(qp->path_mtu);
1354 len = be32_to_cpu(reth->length);
1355 if (unlikely(offset + len > e->rdma_sge.sge.sge_length))
1356 goto unlock_done;
1357 if (len != 0) {
1358 u32 rkey = be32_to_cpu(reth->rkey);
1359 u64 vaddr = be64_to_cpu(reth->vaddr);
1360 int ok;
1361
1362 ok = ipath_rkey_ok(qp, &e->rdma_sge,
1363 len, vaddr, rkey,
1364 IB_ACCESS_REMOTE_READ);
1365 if (unlikely(!ok))
1366 goto unlock_done;
1367 } else {
1368 e->rdma_sge.sg_list = NULL;
1369 e->rdma_sge.num_sge = 0;
1370 e->rdma_sge.sge.mr = NULL;
1371 e->rdma_sge.sge.vaddr = NULL;
1372 e->rdma_sge.sge.length = 0;
1373 e->rdma_sge.sge.sge_length = 0;
1374 }
1375 e->psn = psn;
1376 qp->s_ack_state = OP(ACKNOWLEDGE);
1377 qp->s_tail_ack_queue = prev;
1378 break;
1379 }
1380
1381 case OP(COMPARE_SWAP):
1382 case OP(FETCH_ADD): {
1383 /*
1384 * If we didn't find the atomic request in the ack queue
1385 * or the send tasklet is already backed up to send an
1386 * earlier entry, we can ignore this request.
1387 */
1388 if (!e || e->opcode != (u8) opcode || old_req)
1389 goto unlock_done;
1390 qp->s_ack_state = OP(ACKNOWLEDGE);
1391 qp->s_tail_ack_queue = prev;
1392 break;
1393 }
1394
1395 default:
1396 if (old_req)
1397 goto unlock_done;
1398 /*
1399 * Resend the most recent ACK if this request is
1400 * after all the previous RDMA reads and atomics.
1401 */
1402 if (i == qp->r_head_ack_queue) {
1403 spin_unlock_irq(&qp->s_lock);
1404 qp->r_nak_state = 0;
1405 qp->r_ack_psn = qp->r_psn - 1;
1406 goto send_ack;
1407 }
1408 /*
1409 * Resend the RDMA read or atomic op which
1410 * ACKs this duplicate request.
1411 */
1412 qp->s_ack_state = OP(ACKNOWLEDGE);
1413 qp->s_tail_ack_queue = i;
1414 break;
1415 }
1416 qp->r_nak_state = 0;
1417 spin_unlock_irq(&qp->s_lock);
1418 tasklet_hi_schedule(&qp->s_task);
1419
1420 unlock_done:
1421 spin_unlock_irq(&qp->s_lock);
1422 done:
1423 return 1;
1424
1425 send_ack:
1426 return 0;
1427 }
1428
1429 static void ipath_rc_error(struct ipath_qp *qp, enum ib_wc_status err)
1430 {
1431 spin_lock_irq(&qp->s_lock);
1432 qp->state = IB_QPS_ERR;
1433 ipath_error_qp(qp, err);
1434 spin_unlock_irq(&qp->s_lock);
1435 }
1436
1437 /**
1438 * ipath_rc_rcv - process an incoming RC packet
1439 * @dev: the device this packet came in on
1440 * @hdr: the header of this packet
1441 * @has_grh: true if the header has a GRH
1442 * @data: the packet data
1443 * @tlen: the packet length
1444 * @qp: the QP for this packet
1445 *
1446 * This is called from ipath_qp_rcv() to process an incoming RC packet
1447 * for the given QP.
1448 * Called at interrupt level.
1449 */
1450 void ipath_rc_rcv(struct ipath_ibdev *dev, struct ipath_ib_header *hdr,
1451 int has_grh, void *data, u32 tlen, struct ipath_qp *qp)
1452 {
1453 struct ipath_other_headers *ohdr;
1454 u32 opcode;
1455 u32 hdrsize;
1456 u32 psn;
1457 u32 pad;
1458 struct ib_wc wc;
1459 u32 pmtu = ib_mtu_enum_to_int(qp->path_mtu);
1460 int diff;
1461 struct ib_reth *reth;
1462 int header_in_data;
1463
1464 /* Validate the SLID. See Ch. 9.6.1.5 */
1465 if (unlikely(be16_to_cpu(hdr->lrh[3]) != qp->remote_ah_attr.dlid))
1466 goto done;
1467
1468 /* Check for GRH */
1469 if (!has_grh) {
1470 ohdr = &hdr->u.oth;
1471 hdrsize = 8 + 12; /* LRH + BTH */
1472 psn = be32_to_cpu(ohdr->bth[2]);
1473 header_in_data = 0;
1474 } else {
1475 ohdr = &hdr->u.l.oth;
1476 hdrsize = 8 + 40 + 12; /* LRH + GRH + BTH */
1477 /*
1478 * The header with GRH is 60 bytes and the core driver sets
1479 * the eager header buffer size to 56 bytes so the last 4
1480 * bytes of the BTH header (PSN) is in the data buffer.
1481 */
1482 header_in_data = dev->dd->ipath_rcvhdrentsize == 16;
1483 if (header_in_data) {
1484 psn = be32_to_cpu(((__be32 *) data)[0]);
1485 data += sizeof(__be32);
1486 } else
1487 psn = be32_to_cpu(ohdr->bth[2]);
1488 }
1489
1490 /*
1491 * Process responses (ACKs) before anything else. Note that the
1492 * packet sequence number will be for something in the send work
1493 * queue rather than the expected receive packet sequence number.
1494 * In other words, this QP is the requester.
1495 */
1496 opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
1497 if (opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
1498 opcode <= OP(ATOMIC_ACKNOWLEDGE)) {
1499 ipath_rc_rcv_resp(dev, ohdr, data, tlen, qp, opcode, psn,
1500 hdrsize, pmtu, header_in_data);
1501 goto done;
1502 }
1503
1504 /* Compute 24 bits worth of difference. */
1505 diff = ipath_cmp24(psn, qp->r_psn);
1506 if (unlikely(diff)) {
1507 if (ipath_rc_rcv_error(dev, ohdr, data, qp, opcode,
1508 psn, diff, header_in_data))
1509 goto done;
1510 goto send_ack;
1511 }
1512
1513 /* Check for opcode sequence errors. */
1514 switch (qp->r_state) {
1515 case OP(SEND_FIRST):
1516 case OP(SEND_MIDDLE):
1517 if (opcode == OP(SEND_MIDDLE) ||
1518 opcode == OP(SEND_LAST) ||
1519 opcode == OP(SEND_LAST_WITH_IMMEDIATE))
1520 break;
1521 nack_inv:
1522 ipath_rc_error(qp, IB_WC_REM_INV_REQ_ERR);
1523 qp->r_nak_state = IB_NAK_INVALID_REQUEST;
1524 qp->r_ack_psn = qp->r_psn;
1525 goto send_ack;
1526
1527 case OP(RDMA_WRITE_FIRST):
1528 case OP(RDMA_WRITE_MIDDLE):
1529 if (opcode == OP(RDMA_WRITE_MIDDLE) ||
1530 opcode == OP(RDMA_WRITE_LAST) ||
1531 opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
1532 break;
1533 goto nack_inv;
1534
1535 default:
1536 if (opcode == OP(SEND_MIDDLE) ||
1537 opcode == OP(SEND_LAST) ||
1538 opcode == OP(SEND_LAST_WITH_IMMEDIATE) ||
1539 opcode == OP(RDMA_WRITE_MIDDLE) ||
1540 opcode == OP(RDMA_WRITE_LAST) ||
1541 opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
1542 goto nack_inv;
1543 /*
1544 * Note that it is up to the requester to not send a new
1545 * RDMA read or atomic operation before receiving an ACK
1546 * for the previous operation.
1547 */
1548 break;
1549 }
1550
1551 wc.imm_data = 0;
1552 wc.wc_flags = 0;
1553
1554 /* OK, process the packet. */
1555 switch (opcode) {
1556 case OP(SEND_FIRST):
1557 if (!ipath_get_rwqe(qp, 0)) {
1558 rnr_nak:
1559 /*
1560 * A RNR NAK will ACK earlier sends and RDMA writes.
1561 * Don't queue the NAK if a RDMA read or atomic
1562 * is pending though.
1563 */
1564 if (qp->r_nak_state)
1565 goto done;
1566 qp->r_nak_state = IB_RNR_NAK | qp->r_min_rnr_timer;
1567 qp->r_ack_psn = qp->r_psn;
1568 goto send_ack;
1569 }
1570 qp->r_rcv_len = 0;
1571 /* FALLTHROUGH */
1572 case OP(SEND_MIDDLE):
1573 case OP(RDMA_WRITE_MIDDLE):
1574 send_middle:
1575 /* Check for invalid length PMTU or posted rwqe len. */
1576 if (unlikely(tlen != (hdrsize + pmtu + 4)))
1577 goto nack_inv;
1578 qp->r_rcv_len += pmtu;
1579 if (unlikely(qp->r_rcv_len > qp->r_len))
1580 goto nack_inv;
1581 ipath_copy_sge(&qp->r_sge, data, pmtu);
1582 break;
1583
1584 case OP(RDMA_WRITE_LAST_WITH_IMMEDIATE):
1585 /* consume RWQE */
1586 if (!ipath_get_rwqe(qp, 1))
1587 goto rnr_nak;
1588 goto send_last_imm;
1589
1590 case OP(SEND_ONLY):
1591 case OP(SEND_ONLY_WITH_IMMEDIATE):
1592 if (!ipath_get_rwqe(qp, 0))
1593 goto rnr_nak;
1594 qp->r_rcv_len = 0;
1595 if (opcode == OP(SEND_ONLY))
1596 goto send_last;
1597 /* FALLTHROUGH */
1598 case OP(SEND_LAST_WITH_IMMEDIATE):
1599 send_last_imm:
1600 if (header_in_data) {
1601 wc.imm_data = *(__be32 *) data;
1602 data += sizeof(__be32);
1603 } else {
1604 /* Immediate data comes after BTH */
1605 wc.imm_data = ohdr->u.imm_data;
1606 }
1607 hdrsize += 4;
1608 wc.wc_flags = IB_WC_WITH_IMM;
1609 /* FALLTHROUGH */
1610 case OP(SEND_LAST):
1611 case OP(RDMA_WRITE_LAST):
1612 send_last:
1613 /* Get the number of bytes the message was padded by. */
1614 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1615 /* Check for invalid length. */
1616 /* XXX LAST len should be >= 1 */
1617 if (unlikely(tlen < (hdrsize + pad + 4)))
1618 goto nack_inv;
1619 /* Don't count the CRC. */
1620 tlen -= (hdrsize + pad + 4);
1621 wc.byte_len = tlen + qp->r_rcv_len;
1622 if (unlikely(wc.byte_len > qp->r_len))
1623 goto nack_inv;
1624 ipath_copy_sge(&qp->r_sge, data, tlen);
1625 qp->r_msn++;
1626 if (!qp->r_wrid_valid)
1627 break;
1628 qp->r_wrid_valid = 0;
1629 wc.wr_id = qp->r_wr_id;
1630 wc.status = IB_WC_SUCCESS;
1631 wc.opcode = IB_WC_RECV;
1632 wc.vendor_err = 0;
1633 wc.qp = &qp->ibqp;
1634 wc.src_qp = qp->remote_qpn;
1635 wc.pkey_index = 0;
1636 wc.slid = qp->remote_ah_attr.dlid;
1637 wc.sl = qp->remote_ah_attr.sl;
1638 wc.dlid_path_bits = 0;
1639 wc.port_num = 0;
1640 /* Signal completion event if the solicited bit is set. */
1641 ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
1642 (ohdr->bth[0] &
1643 __constant_cpu_to_be32(1 << 23)) != 0);
1644 break;
1645
1646 case OP(RDMA_WRITE_FIRST):
1647 case OP(RDMA_WRITE_ONLY):
1648 case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE):
1649 /* consume RWQE */
1650 /* RETH comes after BTH */
1651 if (!header_in_data)
1652 reth = &ohdr->u.rc.reth;
1653 else {
1654 reth = (struct ib_reth *)data;
1655 data += sizeof(*reth);
1656 }
1657 hdrsize += sizeof(*reth);
1658 qp->r_len = be32_to_cpu(reth->length);
1659 qp->r_rcv_len = 0;
1660 if (qp->r_len != 0) {
1661 u32 rkey = be32_to_cpu(reth->rkey);
1662 u64 vaddr = be64_to_cpu(reth->vaddr);
1663 int ok;
1664
1665 /* Check rkey & NAK */
1666 ok = ipath_rkey_ok(qp, &qp->r_sge,
1667 qp->r_len, vaddr, rkey,
1668 IB_ACCESS_REMOTE_WRITE);
1669 if (unlikely(!ok))
1670 goto nack_acc;
1671 } else {
1672 qp->r_sge.sg_list = NULL;
1673 qp->r_sge.sge.mr = NULL;
1674 qp->r_sge.sge.vaddr = NULL;
1675 qp->r_sge.sge.length = 0;
1676 qp->r_sge.sge.sge_length = 0;
1677 }
1678 if (unlikely(!(qp->qp_access_flags &
1679 IB_ACCESS_REMOTE_WRITE)))
1680 goto nack_acc;
1681 if (opcode == OP(RDMA_WRITE_FIRST))
1682 goto send_middle;
1683 else if (opcode == OP(RDMA_WRITE_ONLY))
1684 goto send_last;
1685 if (!ipath_get_rwqe(qp, 1))
1686 goto rnr_nak;
1687 goto send_last_imm;
1688
1689 case OP(RDMA_READ_REQUEST): {
1690 struct ipath_ack_entry *e;
1691 u32 len;
1692 u8 next;
1693
1694 if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_READ)))
1695 goto nack_acc;
1696 next = qp->r_head_ack_queue + 1;
1697 if (next > IPATH_MAX_RDMA_ATOMIC)
1698 next = 0;
1699 if (unlikely(next == qp->s_tail_ack_queue))
1700 goto nack_inv;
1701 e = &qp->s_ack_queue[qp->r_head_ack_queue];
1702 /* RETH comes after BTH */
1703 if (!header_in_data)
1704 reth = &ohdr->u.rc.reth;
1705 else {
1706 reth = (struct ib_reth *)data;
1707 data += sizeof(*reth);
1708 }
1709 len = be32_to_cpu(reth->length);
1710 if (len) {
1711 u32 rkey = be32_to_cpu(reth->rkey);
1712 u64 vaddr = be64_to_cpu(reth->vaddr);
1713 int ok;
1714
1715 /* Check rkey & NAK */
1716 ok = ipath_rkey_ok(qp, &e->rdma_sge, len, vaddr,
1717 rkey, IB_ACCESS_REMOTE_READ);
1718 if (unlikely(!ok))
1719 goto nack_acc;
1720 /*
1721 * Update the next expected PSN. We add 1 later
1722 * below, so only add the remainder here.
1723 */
1724 if (len > pmtu)
1725 qp->r_psn += (len - 1) / pmtu;
1726 } else {
1727 e->rdma_sge.sg_list = NULL;
1728 e->rdma_sge.num_sge = 0;
1729 e->rdma_sge.sge.mr = NULL;
1730 e->rdma_sge.sge.vaddr = NULL;
1731 e->rdma_sge.sge.length = 0;
1732 e->rdma_sge.sge.sge_length = 0;
1733 }
1734 e->opcode = opcode;
1735 e->psn = psn;
1736 /*
1737 * We need to increment the MSN here instead of when we
1738 * finish sending the result since a duplicate request would
1739 * increment it more than once.
1740 */
1741 qp->r_msn++;
1742 qp->r_psn++;
1743 qp->r_state = opcode;
1744 qp->r_nak_state = 0;
1745 barrier();
1746 qp->r_head_ack_queue = next;
1747
1748 /* Call ipath_do_rc_send() in another thread. */
1749 tasklet_hi_schedule(&qp->s_task);
1750
1751 goto done;
1752 }
1753
1754 case OP(COMPARE_SWAP):
1755 case OP(FETCH_ADD): {
1756 struct ib_atomic_eth *ateth;
1757 struct ipath_ack_entry *e;
1758 u64 vaddr;
1759 atomic64_t *maddr;
1760 u64 sdata;
1761 u32 rkey;
1762 u8 next;
1763
1764 if (unlikely(!(qp->qp_access_flags &
1765 IB_ACCESS_REMOTE_ATOMIC)))
1766 goto nack_acc;
1767 next = qp->r_head_ack_queue + 1;
1768 if (next > IPATH_MAX_RDMA_ATOMIC)
1769 next = 0;
1770 if (unlikely(next == qp->s_tail_ack_queue))
1771 goto nack_inv;
1772 if (!header_in_data)
1773 ateth = &ohdr->u.atomic_eth;
1774 else
1775 ateth = (struct ib_atomic_eth *)data;
1776 vaddr = ((u64) be32_to_cpu(ateth->vaddr[0]) << 32) |
1777 be32_to_cpu(ateth->vaddr[1]);
1778 if (unlikely(vaddr & (sizeof(u64) - 1)))
1779 goto nack_inv;
1780 rkey = be32_to_cpu(ateth->rkey);
1781 /* Check rkey & NAK */
1782 if (unlikely(!ipath_rkey_ok(qp, &qp->r_sge,
1783 sizeof(u64), vaddr, rkey,
1784 IB_ACCESS_REMOTE_ATOMIC)))
1785 goto nack_acc;
1786 /* Perform atomic OP and save result. */
1787 maddr = (atomic64_t *) qp->r_sge.sge.vaddr;
1788 sdata = be64_to_cpu(ateth->swap_data);
1789 e = &qp->s_ack_queue[qp->r_head_ack_queue];
1790 e->atomic_data = (opcode == OP(FETCH_ADD)) ?
1791 (u64) atomic64_add_return(sdata, maddr) - sdata :
1792 (u64) cmpxchg((u64 *) qp->r_sge.sge.vaddr,
1793 be64_to_cpu(ateth->compare_data),
1794 sdata);
1795 e->opcode = opcode;
1796 e->psn = psn & IPATH_PSN_MASK;
1797 qp->r_msn++;
1798 qp->r_psn++;
1799 qp->r_state = opcode;
1800 qp->r_nak_state = 0;
1801 barrier();
1802 qp->r_head_ack_queue = next;
1803
1804 /* Call ipath_do_rc_send() in another thread. */
1805 tasklet_hi_schedule(&qp->s_task);
1806
1807 goto done;
1808 }
1809
1810 default:
1811 /* NAK unknown opcodes. */
1812 goto nack_inv;
1813 }
1814 qp->r_psn++;
1815 qp->r_state = opcode;
1816 qp->r_ack_psn = psn;
1817 qp->r_nak_state = 0;
1818 /* Send an ACK if requested or required. */
1819 if (psn & (1 << 31))
1820 goto send_ack;
1821 goto done;
1822
1823 nack_acc:
1824 ipath_rc_error(qp, IB_WC_REM_ACCESS_ERR);
1825 qp->r_nak_state = IB_NAK_REMOTE_ACCESS_ERROR;
1826 qp->r_ack_psn = qp->r_psn;
1827
1828 send_ack:
1829 send_rc_ack(qp);
1830
1831 done:
1832 return;
1833 }
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