1 // SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
2 /*
3 * Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
4 * Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
5 */
6
7 #include <linux/skbuff.h>
8
9 #include "rxe.h"
10 #include "rxe_loc.h"
11 #include "rxe_queue.h"
12 #include "rxe_task.h"
13
14 enum comp_state {
15 COMPST_GET_ACK,
16 COMPST_GET_WQE,
17 COMPST_COMP_WQE,
18 COMPST_COMP_ACK,
19 COMPST_CHECK_PSN,
20 COMPST_CHECK_ACK,
21 COMPST_READ,
22 COMPST_ATOMIC,
23 COMPST_WRITE_SEND,
24 COMPST_UPDATE_COMP,
25 COMPST_ERROR_RETRY,
26 COMPST_RNR_RETRY,
27 COMPST_ERROR,
28 COMPST_EXIT, /* We have an issue, and we want to rerun the completer */
29 COMPST_DONE, /* The completer finished successflly */
30 };
31
32 static char *comp_state_name[] = {
33 [COMPST_GET_ACK] = "GET ACK",
34 [COMPST_GET_WQE] = "GET WQE",
35 [COMPST_COMP_WQE] = "COMP WQE",
36 [COMPST_COMP_ACK] = "COMP ACK",
37 [COMPST_CHECK_PSN] = "CHECK PSN",
38 [COMPST_CHECK_ACK] = "CHECK ACK",
39 [COMPST_READ] = "READ",
40 [COMPST_ATOMIC] = "ATOMIC",
41 [COMPST_WRITE_SEND] = "WRITE/SEND",
42 [COMPST_UPDATE_COMP] = "UPDATE COMP",
43 [COMPST_ERROR_RETRY] = "ERROR RETRY",
44 [COMPST_RNR_RETRY] = "RNR RETRY",
45 [COMPST_ERROR] = "ERROR",
46 [COMPST_EXIT] = "EXIT",
47 [COMPST_DONE] = "DONE",
48 };
49
50 static unsigned long rnrnak_usec[32] = {
51 [IB_RNR_TIMER_655_36] = 655360,
52 [IB_RNR_TIMER_000_01] = 10,
53 [IB_RNR_TIMER_000_02] = 20,
54 [IB_RNR_TIMER_000_03] = 30,
55 [IB_RNR_TIMER_000_04] = 40,
56 [IB_RNR_TIMER_000_06] = 60,
57 [IB_RNR_TIMER_000_08] = 80,
58 [IB_RNR_TIMER_000_12] = 120,
59 [IB_RNR_TIMER_000_16] = 160,
60 [IB_RNR_TIMER_000_24] = 240,
61 [IB_RNR_TIMER_000_32] = 320,
62 [IB_RNR_TIMER_000_48] = 480,
63 [IB_RNR_TIMER_000_64] = 640,
64 [IB_RNR_TIMER_000_96] = 960,
65 [IB_RNR_TIMER_001_28] = 1280,
66 [IB_RNR_TIMER_001_92] = 1920,
67 [IB_RNR_TIMER_002_56] = 2560,
68 [IB_RNR_TIMER_003_84] = 3840,
69 [IB_RNR_TIMER_005_12] = 5120,
70 [IB_RNR_TIMER_007_68] = 7680,
71 [IB_RNR_TIMER_010_24] = 10240,
72 [IB_RNR_TIMER_015_36] = 15360,
73 [IB_RNR_TIMER_020_48] = 20480,
74 [IB_RNR_TIMER_030_72] = 30720,
75 [IB_RNR_TIMER_040_96] = 40960,
76 [IB_RNR_TIMER_061_44] = 61410,
77 [IB_RNR_TIMER_081_92] = 81920,
78 [IB_RNR_TIMER_122_88] = 122880,
79 [IB_RNR_TIMER_163_84] = 163840,
80 [IB_RNR_TIMER_245_76] = 245760,
81 [IB_RNR_TIMER_327_68] = 327680,
82 [IB_RNR_TIMER_491_52] = 491520,
83 };
84
rnrnak_jiffies(u8 timeout)85 static inline unsigned long rnrnak_jiffies(u8 timeout)
86 {
87 return max_t(unsigned long,
88 usecs_to_jiffies(rnrnak_usec[timeout]), 1);
89 }
90
wr_to_wc_opcode(enum ib_wr_opcode opcode)91 static enum ib_wc_opcode wr_to_wc_opcode(enum ib_wr_opcode opcode)
92 {
93 switch (opcode) {
94 case IB_WR_RDMA_WRITE: return IB_WC_RDMA_WRITE;
95 case IB_WR_RDMA_WRITE_WITH_IMM: return IB_WC_RDMA_WRITE;
96 case IB_WR_SEND: return IB_WC_SEND;
97 case IB_WR_SEND_WITH_IMM: return IB_WC_SEND;
98 case IB_WR_RDMA_READ: return IB_WC_RDMA_READ;
99 case IB_WR_ATOMIC_CMP_AND_SWP: return IB_WC_COMP_SWAP;
100 case IB_WR_ATOMIC_FETCH_AND_ADD: return IB_WC_FETCH_ADD;
101 case IB_WR_LSO: return IB_WC_LSO;
102 case IB_WR_SEND_WITH_INV: return IB_WC_SEND;
103 case IB_WR_RDMA_READ_WITH_INV: return IB_WC_RDMA_READ;
104 case IB_WR_LOCAL_INV: return IB_WC_LOCAL_INV;
105 case IB_WR_REG_MR: return IB_WC_REG_MR;
106 case IB_WR_BIND_MW: return IB_WC_BIND_MW;
107
108 default:
109 return 0xff;
110 }
111 }
112
retransmit_timer(struct timer_list * t)113 void retransmit_timer(struct timer_list *t)
114 {
115 struct rxe_qp *qp = from_timer(qp, t, retrans_timer);
116
117 if (qp->valid) {
118 qp->comp.timeout = 1;
119 rxe_run_task(&qp->comp.task, 1);
120 }
121 }
122
rxe_comp_queue_pkt(struct rxe_qp * qp,struct sk_buff * skb)123 void rxe_comp_queue_pkt(struct rxe_qp *qp, struct sk_buff *skb)
124 {
125 int must_sched;
126
127 skb_queue_tail(&qp->resp_pkts, skb);
128
129 must_sched = skb_queue_len(&qp->resp_pkts) > 1;
130 if (must_sched != 0)
131 rxe_counter_inc(SKB_TO_PKT(skb)->rxe, RXE_CNT_COMPLETER_SCHED);
132
133 rxe_run_task(&qp->comp.task, must_sched);
134 }
135
get_wqe(struct rxe_qp * qp,struct rxe_pkt_info * pkt,struct rxe_send_wqe ** wqe_p)136 static inline enum comp_state get_wqe(struct rxe_qp *qp,
137 struct rxe_pkt_info *pkt,
138 struct rxe_send_wqe **wqe_p)
139 {
140 struct rxe_send_wqe *wqe;
141
142 /* we come here whether or not we found a response packet to see if
143 * there are any posted WQEs
144 */
145 wqe = queue_head(qp->sq.queue, QUEUE_TYPE_FROM_CLIENT);
146 *wqe_p = wqe;
147
148 /* no WQE or requester has not started it yet */
149 if (!wqe || wqe->state == wqe_state_posted)
150 return pkt ? COMPST_DONE : COMPST_EXIT;
151
152 /* WQE does not require an ack */
153 if (wqe->state == wqe_state_done)
154 return COMPST_COMP_WQE;
155
156 /* WQE caused an error */
157 if (wqe->state == wqe_state_error)
158 return COMPST_ERROR;
159
160 /* we have a WQE, if we also have an ack check its PSN */
161 return pkt ? COMPST_CHECK_PSN : COMPST_EXIT;
162 }
163
reset_retry_counters(struct rxe_qp * qp)164 static inline void reset_retry_counters(struct rxe_qp *qp)
165 {
166 qp->comp.retry_cnt = qp->attr.retry_cnt;
167 qp->comp.rnr_retry = qp->attr.rnr_retry;
168 qp->comp.started_retry = 0;
169 }
170
check_psn(struct rxe_qp * qp,struct rxe_pkt_info * pkt,struct rxe_send_wqe * wqe)171 static inline enum comp_state check_psn(struct rxe_qp *qp,
172 struct rxe_pkt_info *pkt,
173 struct rxe_send_wqe *wqe)
174 {
175 s32 diff;
176
177 /* check to see if response is past the oldest WQE. if it is, complete
178 * send/write or error read/atomic
179 */
180 diff = psn_compare(pkt->psn, wqe->last_psn);
181 if (diff > 0) {
182 if (wqe->state == wqe_state_pending) {
183 if (wqe->mask & WR_ATOMIC_OR_READ_MASK)
184 return COMPST_ERROR_RETRY;
185
186 reset_retry_counters(qp);
187 return COMPST_COMP_WQE;
188 } else {
189 return COMPST_DONE;
190 }
191 }
192
193 /* compare response packet to expected response */
194 diff = psn_compare(pkt->psn, qp->comp.psn);
195 if (diff < 0) {
196 /* response is most likely a retried packet if it matches an
197 * uncompleted WQE go complete it else ignore it
198 */
199 if (pkt->psn == wqe->last_psn)
200 return COMPST_COMP_ACK;
201 else
202 return COMPST_DONE;
203 } else if ((diff > 0) && (wqe->mask & WR_ATOMIC_OR_READ_MASK)) {
204 return COMPST_DONE;
205 } else {
206 return COMPST_CHECK_ACK;
207 }
208 }
209
check_ack(struct rxe_qp * qp,struct rxe_pkt_info * pkt,struct rxe_send_wqe * wqe)210 static inline enum comp_state check_ack(struct rxe_qp *qp,
211 struct rxe_pkt_info *pkt,
212 struct rxe_send_wqe *wqe)
213 {
214 unsigned int mask = pkt->mask;
215 u8 syn;
216 struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
217
218 /* Check the sequence only */
219 switch (qp->comp.opcode) {
220 case -1:
221 /* Will catch all *_ONLY cases. */
222 if (!(mask & RXE_START_MASK))
223 return COMPST_ERROR;
224
225 break;
226
227 case IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST:
228 case IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE:
229 if (pkt->opcode != IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE &&
230 pkt->opcode != IB_OPCODE_RC_RDMA_READ_RESPONSE_LAST) {
231 /* read retries of partial data may restart from
232 * read response first or response only.
233 */
234 if ((pkt->psn == wqe->first_psn &&
235 pkt->opcode ==
236 IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST) ||
237 (wqe->first_psn == wqe->last_psn &&
238 pkt->opcode ==
239 IB_OPCODE_RC_RDMA_READ_RESPONSE_ONLY))
240 break;
241
242 return COMPST_ERROR;
243 }
244 break;
245 default:
246 WARN_ON_ONCE(1);
247 }
248
249 /* Check operation validity. */
250 switch (pkt->opcode) {
251 case IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST:
252 case IB_OPCODE_RC_RDMA_READ_RESPONSE_LAST:
253 case IB_OPCODE_RC_RDMA_READ_RESPONSE_ONLY:
254 syn = aeth_syn(pkt);
255
256 if ((syn & AETH_TYPE_MASK) != AETH_ACK)
257 return COMPST_ERROR;
258
259 fallthrough;
260 /* (IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE doesn't have an AETH)
261 */
262 case IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE:
263 if (wqe->wr.opcode != IB_WR_RDMA_READ &&
264 wqe->wr.opcode != IB_WR_RDMA_READ_WITH_INV) {
265 wqe->status = IB_WC_FATAL_ERR;
266 return COMPST_ERROR;
267 }
268 reset_retry_counters(qp);
269 return COMPST_READ;
270
271 case IB_OPCODE_RC_ATOMIC_ACKNOWLEDGE:
272 syn = aeth_syn(pkt);
273
274 if ((syn & AETH_TYPE_MASK) != AETH_ACK)
275 return COMPST_ERROR;
276
277 if (wqe->wr.opcode != IB_WR_ATOMIC_CMP_AND_SWP &&
278 wqe->wr.opcode != IB_WR_ATOMIC_FETCH_AND_ADD)
279 return COMPST_ERROR;
280 reset_retry_counters(qp);
281 return COMPST_ATOMIC;
282
283 case IB_OPCODE_RC_ACKNOWLEDGE:
284 syn = aeth_syn(pkt);
285 switch (syn & AETH_TYPE_MASK) {
286 case AETH_ACK:
287 reset_retry_counters(qp);
288 return COMPST_WRITE_SEND;
289
290 case AETH_RNR_NAK:
291 rxe_counter_inc(rxe, RXE_CNT_RCV_RNR);
292 return COMPST_RNR_RETRY;
293
294 case AETH_NAK:
295 switch (syn) {
296 case AETH_NAK_PSN_SEQ_ERROR:
297 /* a nak implicitly acks all packets with psns
298 * before
299 */
300 if (psn_compare(pkt->psn, qp->comp.psn) > 0) {
301 rxe_counter_inc(rxe,
302 RXE_CNT_RCV_SEQ_ERR);
303 qp->comp.psn = pkt->psn;
304 if (qp->req.wait_psn) {
305 qp->req.wait_psn = 0;
306 rxe_run_task(&qp->req.task, 0);
307 }
308 }
309 return COMPST_ERROR_RETRY;
310
311 case AETH_NAK_INVALID_REQ:
312 wqe->status = IB_WC_REM_INV_REQ_ERR;
313 return COMPST_ERROR;
314
315 case AETH_NAK_REM_ACC_ERR:
316 wqe->status = IB_WC_REM_ACCESS_ERR;
317 return COMPST_ERROR;
318
319 case AETH_NAK_REM_OP_ERR:
320 wqe->status = IB_WC_REM_OP_ERR;
321 return COMPST_ERROR;
322
323 default:
324 pr_warn("unexpected nak %x\n", syn);
325 wqe->status = IB_WC_REM_OP_ERR;
326 return COMPST_ERROR;
327 }
328
329 default:
330 return COMPST_ERROR;
331 }
332 break;
333
334 default:
335 pr_warn("unexpected opcode\n");
336 }
337
338 return COMPST_ERROR;
339 }
340
do_read(struct rxe_qp * qp,struct rxe_pkt_info * pkt,struct rxe_send_wqe * wqe)341 static inline enum comp_state do_read(struct rxe_qp *qp,
342 struct rxe_pkt_info *pkt,
343 struct rxe_send_wqe *wqe)
344 {
345 int ret;
346
347 ret = copy_data(qp->pd, IB_ACCESS_LOCAL_WRITE,
348 &wqe->dma, payload_addr(pkt),
349 payload_size(pkt), RXE_TO_MR_OBJ);
350 if (ret) {
351 wqe->status = IB_WC_LOC_PROT_ERR;
352 return COMPST_ERROR;
353 }
354
355 if (wqe->dma.resid == 0 && (pkt->mask & RXE_END_MASK))
356 return COMPST_COMP_ACK;
357
358 return COMPST_UPDATE_COMP;
359 }
360
do_atomic(struct rxe_qp * qp,struct rxe_pkt_info * pkt,struct rxe_send_wqe * wqe)361 static inline enum comp_state do_atomic(struct rxe_qp *qp,
362 struct rxe_pkt_info *pkt,
363 struct rxe_send_wqe *wqe)
364 {
365 int ret;
366
367 u64 atomic_orig = atmack_orig(pkt);
368
369 ret = copy_data(qp->pd, IB_ACCESS_LOCAL_WRITE,
370 &wqe->dma, &atomic_orig,
371 sizeof(u64), RXE_TO_MR_OBJ);
372 if (ret) {
373 wqe->status = IB_WC_LOC_PROT_ERR;
374 return COMPST_ERROR;
375 }
376
377 return COMPST_COMP_ACK;
378 }
379
make_send_cqe(struct rxe_qp * qp,struct rxe_send_wqe * wqe,struct rxe_cqe * cqe)380 static void make_send_cqe(struct rxe_qp *qp, struct rxe_send_wqe *wqe,
381 struct rxe_cqe *cqe)
382 {
383 struct ib_wc *wc = &cqe->ibwc;
384 struct ib_uverbs_wc *uwc = &cqe->uibwc;
385
386 memset(cqe, 0, sizeof(*cqe));
387
388 if (!qp->is_user) {
389 wc->wr_id = wqe->wr.wr_id;
390 wc->status = wqe->status;
391 wc->qp = &qp->ibqp;
392 } else {
393 uwc->wr_id = wqe->wr.wr_id;
394 uwc->status = wqe->status;
395 uwc->qp_num = qp->ibqp.qp_num;
396 }
397
398 if (wqe->status == IB_WC_SUCCESS) {
399 if (!qp->is_user) {
400 wc->opcode = wr_to_wc_opcode(wqe->wr.opcode);
401 if (wqe->wr.opcode == IB_WR_RDMA_WRITE_WITH_IMM ||
402 wqe->wr.opcode == IB_WR_SEND_WITH_IMM)
403 wc->wc_flags = IB_WC_WITH_IMM;
404 wc->byte_len = wqe->dma.length;
405 } else {
406 uwc->opcode = wr_to_wc_opcode(wqe->wr.opcode);
407 if (wqe->wr.opcode == IB_WR_RDMA_WRITE_WITH_IMM ||
408 wqe->wr.opcode == IB_WR_SEND_WITH_IMM)
409 uwc->wc_flags = IB_WC_WITH_IMM;
410 uwc->byte_len = wqe->dma.length;
411 }
412 }
413 }
414
415 /*
416 * IBA Spec. Section 10.7.3.1 SIGNALED COMPLETIONS
417 * ---------8<---------8<-------------
418 * ...Note that if a completion error occurs, a Work Completion
419 * will always be generated, even if the signaling
420 * indicator requests an Unsignaled Completion.
421 * ---------8<---------8<-------------
422 */
do_complete(struct rxe_qp * qp,struct rxe_send_wqe * wqe)423 static void do_complete(struct rxe_qp *qp, struct rxe_send_wqe *wqe)
424 {
425 struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
426 struct rxe_cqe cqe;
427 bool post;
428
429 /* do we need to post a completion */
430 post = ((qp->sq_sig_type == IB_SIGNAL_ALL_WR) ||
431 (wqe->wr.send_flags & IB_SEND_SIGNALED) ||
432 wqe->status != IB_WC_SUCCESS);
433
434 if (post)
435 make_send_cqe(qp, wqe, &cqe);
436
437 queue_advance_consumer(qp->sq.queue, QUEUE_TYPE_FROM_CLIENT);
438
439 if (post)
440 rxe_cq_post(qp->scq, &cqe, 0);
441
442 if (wqe->wr.opcode == IB_WR_SEND ||
443 wqe->wr.opcode == IB_WR_SEND_WITH_IMM ||
444 wqe->wr.opcode == IB_WR_SEND_WITH_INV)
445 rxe_counter_inc(rxe, RXE_CNT_RDMA_SEND);
446
447 /*
448 * we completed something so let req run again
449 * if it is trying to fence
450 */
451 if (qp->req.wait_fence) {
452 qp->req.wait_fence = 0;
453 rxe_run_task(&qp->req.task, 0);
454 }
455 }
456
complete_ack(struct rxe_qp * qp,struct rxe_pkt_info * pkt,struct rxe_send_wqe * wqe)457 static inline enum comp_state complete_ack(struct rxe_qp *qp,
458 struct rxe_pkt_info *pkt,
459 struct rxe_send_wqe *wqe)
460 {
461 unsigned long flags;
462
463 if (wqe->has_rd_atomic) {
464 wqe->has_rd_atomic = 0;
465 atomic_inc(&qp->req.rd_atomic);
466 if (qp->req.need_rd_atomic) {
467 qp->comp.timeout_retry = 0;
468 qp->req.need_rd_atomic = 0;
469 rxe_run_task(&qp->req.task, 0);
470 }
471 }
472
473 if (unlikely(qp->req.state == QP_STATE_DRAIN)) {
474 /* state_lock used by requester & completer */
475 spin_lock_irqsave(&qp->state_lock, flags);
476 if ((qp->req.state == QP_STATE_DRAIN) &&
477 (qp->comp.psn == qp->req.psn)) {
478 qp->req.state = QP_STATE_DRAINED;
479 spin_unlock_irqrestore(&qp->state_lock, flags);
480
481 if (qp->ibqp.event_handler) {
482 struct ib_event ev;
483
484 ev.device = qp->ibqp.device;
485 ev.element.qp = &qp->ibqp;
486 ev.event = IB_EVENT_SQ_DRAINED;
487 qp->ibqp.event_handler(&ev,
488 qp->ibqp.qp_context);
489 }
490 } else {
491 spin_unlock_irqrestore(&qp->state_lock, flags);
492 }
493 }
494
495 do_complete(qp, wqe);
496
497 if (psn_compare(pkt->psn, qp->comp.psn) >= 0)
498 return COMPST_UPDATE_COMP;
499 else
500 return COMPST_DONE;
501 }
502
complete_wqe(struct rxe_qp * qp,struct rxe_pkt_info * pkt,struct rxe_send_wqe * wqe)503 static inline enum comp_state complete_wqe(struct rxe_qp *qp,
504 struct rxe_pkt_info *pkt,
505 struct rxe_send_wqe *wqe)
506 {
507 if (pkt && wqe->state == wqe_state_pending) {
508 if (psn_compare(wqe->last_psn, qp->comp.psn) >= 0) {
509 qp->comp.psn = (wqe->last_psn + 1) & BTH_PSN_MASK;
510 qp->comp.opcode = -1;
511 }
512
513 if (qp->req.wait_psn) {
514 qp->req.wait_psn = 0;
515 rxe_run_task(&qp->req.task, 1);
516 }
517 }
518
519 do_complete(qp, wqe);
520
521 return COMPST_GET_WQE;
522 }
523
rxe_drain_resp_pkts(struct rxe_qp * qp,bool notify)524 static void rxe_drain_resp_pkts(struct rxe_qp *qp, bool notify)
525 {
526 struct sk_buff *skb;
527 struct rxe_send_wqe *wqe;
528 struct rxe_queue *q = qp->sq.queue;
529
530 while ((skb = skb_dequeue(&qp->resp_pkts))) {
531 rxe_drop_ref(qp);
532 kfree_skb(skb);
533 ib_device_put(qp->ibqp.device);
534 }
535
536 while ((wqe = queue_head(q, q->type))) {
537 if (notify) {
538 wqe->status = IB_WC_WR_FLUSH_ERR;
539 do_complete(qp, wqe);
540 } else {
541 queue_advance_consumer(q, q->type);
542 }
543 }
544 }
545
free_pkt(struct rxe_pkt_info * pkt)546 static void free_pkt(struct rxe_pkt_info *pkt)
547 {
548 struct sk_buff *skb = PKT_TO_SKB(pkt);
549 struct rxe_qp *qp = pkt->qp;
550 struct ib_device *dev = qp->ibqp.device;
551
552 kfree_skb(skb);
553 rxe_drop_ref(qp);
554 ib_device_put(dev);
555 }
556
rxe_completer(void * arg)557 int rxe_completer(void *arg)
558 {
559 struct rxe_qp *qp = (struct rxe_qp *)arg;
560 struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
561 struct rxe_send_wqe *wqe = NULL;
562 struct sk_buff *skb = NULL;
563 struct rxe_pkt_info *pkt = NULL;
564 enum comp_state state;
565 int ret = 0;
566
567 rxe_add_ref(qp);
568
569 if (!qp->valid || qp->req.state == QP_STATE_ERROR ||
570 qp->req.state == QP_STATE_RESET) {
571 rxe_drain_resp_pkts(qp, qp->valid &&
572 qp->req.state == QP_STATE_ERROR);
573 ret = -EAGAIN;
574 goto done;
575 }
576
577 if (qp->comp.timeout) {
578 qp->comp.timeout_retry = 1;
579 qp->comp.timeout = 0;
580 } else {
581 qp->comp.timeout_retry = 0;
582 }
583
584 if (qp->req.need_retry) {
585 ret = -EAGAIN;
586 goto done;
587 }
588
589 state = COMPST_GET_ACK;
590
591 while (1) {
592 pr_debug("qp#%d state = %s\n", qp_num(qp),
593 comp_state_name[state]);
594 switch (state) {
595 case COMPST_GET_ACK:
596 skb = skb_dequeue(&qp->resp_pkts);
597 if (skb) {
598 pkt = SKB_TO_PKT(skb);
599 qp->comp.timeout_retry = 0;
600 }
601 state = COMPST_GET_WQE;
602 break;
603
604 case COMPST_GET_WQE:
605 state = get_wqe(qp, pkt, &wqe);
606 break;
607
608 case COMPST_CHECK_PSN:
609 state = check_psn(qp, pkt, wqe);
610 break;
611
612 case COMPST_CHECK_ACK:
613 state = check_ack(qp, pkt, wqe);
614 break;
615
616 case COMPST_READ:
617 state = do_read(qp, pkt, wqe);
618 break;
619
620 case COMPST_ATOMIC:
621 state = do_atomic(qp, pkt, wqe);
622 break;
623
624 case COMPST_WRITE_SEND:
625 if (wqe->state == wqe_state_pending &&
626 wqe->last_psn == pkt->psn)
627 state = COMPST_COMP_ACK;
628 else
629 state = COMPST_UPDATE_COMP;
630 break;
631
632 case COMPST_COMP_ACK:
633 state = complete_ack(qp, pkt, wqe);
634 break;
635
636 case COMPST_COMP_WQE:
637 state = complete_wqe(qp, pkt, wqe);
638 break;
639
640 case COMPST_UPDATE_COMP:
641 if (pkt->mask & RXE_END_MASK)
642 qp->comp.opcode = -1;
643 else
644 qp->comp.opcode = pkt->opcode;
645
646 if (psn_compare(pkt->psn, qp->comp.psn) >= 0)
647 qp->comp.psn = (pkt->psn + 1) & BTH_PSN_MASK;
648
649 if (qp->req.wait_psn) {
650 qp->req.wait_psn = 0;
651 rxe_run_task(&qp->req.task, 1);
652 }
653
654 state = COMPST_DONE;
655 break;
656
657 case COMPST_DONE:
658 goto done;
659
660 case COMPST_EXIT:
661 if (qp->comp.timeout_retry && wqe) {
662 state = COMPST_ERROR_RETRY;
663 break;
664 }
665
666 /* re reset the timeout counter if
667 * (1) QP is type RC
668 * (2) the QP is alive
669 * (3) there is a packet sent by the requester that
670 * might be acked (we still might get spurious
671 * timeouts but try to keep them as few as possible)
672 * (4) the timeout parameter is set
673 */
674 if ((qp_type(qp) == IB_QPT_RC) &&
675 (qp->req.state == QP_STATE_READY) &&
676 (psn_compare(qp->req.psn, qp->comp.psn) > 0) &&
677 qp->qp_timeout_jiffies)
678 mod_timer(&qp->retrans_timer,
679 jiffies + qp->qp_timeout_jiffies);
680 ret = -EAGAIN;
681 goto done;
682
683 case COMPST_ERROR_RETRY:
684 /* we come here if the retry timer fired and we did
685 * not receive a response packet. try to retry the send
686 * queue if that makes sense and the limits have not
687 * been exceeded. remember that some timeouts are
688 * spurious since we do not reset the timer but kick
689 * it down the road or let it expire
690 */
691
692 /* there is nothing to retry in this case */
693 if (!wqe || (wqe->state == wqe_state_posted)) {
694 ret = -EAGAIN;
695 goto done;
696 }
697
698 /* if we've started a retry, don't start another
699 * retry sequence, unless this is a timeout.
700 */
701 if (qp->comp.started_retry &&
702 !qp->comp.timeout_retry)
703 goto done;
704
705 if (qp->comp.retry_cnt > 0) {
706 if (qp->comp.retry_cnt != 7)
707 qp->comp.retry_cnt--;
708
709 /* no point in retrying if we have already
710 * seen the last ack that the requester could
711 * have caused
712 */
713 if (psn_compare(qp->req.psn,
714 qp->comp.psn) > 0) {
715 /* tell the requester to retry the
716 * send queue next time around
717 */
718 rxe_counter_inc(rxe,
719 RXE_CNT_COMP_RETRY);
720 qp->req.need_retry = 1;
721 qp->comp.started_retry = 1;
722 rxe_run_task(&qp->req.task, 0);
723 }
724 goto done;
725
726 } else {
727 rxe_counter_inc(rxe, RXE_CNT_RETRY_EXCEEDED);
728 wqe->status = IB_WC_RETRY_EXC_ERR;
729 state = COMPST_ERROR;
730 }
731 break;
732
733 case COMPST_RNR_RETRY:
734 if (qp->comp.rnr_retry > 0) {
735 if (qp->comp.rnr_retry != 7)
736 qp->comp.rnr_retry--;
737
738 qp->req.need_retry = 1;
739 pr_debug("qp#%d set rnr nak timer\n",
740 qp_num(qp));
741 mod_timer(&qp->rnr_nak_timer,
742 jiffies + rnrnak_jiffies(aeth_syn(pkt)
743 & ~AETH_TYPE_MASK));
744 ret = -EAGAIN;
745 goto done;
746 } else {
747 rxe_counter_inc(rxe,
748 RXE_CNT_RNR_RETRY_EXCEEDED);
749 wqe->status = IB_WC_RNR_RETRY_EXC_ERR;
750 state = COMPST_ERROR;
751 }
752 break;
753
754 case COMPST_ERROR:
755 WARN_ON_ONCE(wqe->status == IB_WC_SUCCESS);
756 do_complete(qp, wqe);
757 rxe_qp_error(qp);
758 ret = -EAGAIN;
759 goto done;
760 }
761 }
762
763 done:
764 if (pkt)
765 free_pkt(pkt);
766 rxe_drop_ref(qp);
767
768 return ret;
769 }
770