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 pr_debug("%s: fired for qp#%d\n", __func__, qp->elem.index);
118
119 if (qp->valid) {
120 qp->comp.timeout = 1;
121 rxe_run_task(&qp->comp.task, 1);
122 }
123 }
124
rxe_comp_queue_pkt(struct rxe_qp * qp,struct sk_buff * skb)125 void rxe_comp_queue_pkt(struct rxe_qp *qp, struct sk_buff *skb)
126 {
127 int must_sched;
128
129 skb_queue_tail(&qp->resp_pkts, skb);
130
131 must_sched = skb_queue_len(&qp->resp_pkts) > 1;
132 if (must_sched != 0)
133 rxe_counter_inc(SKB_TO_PKT(skb)->rxe, RXE_CNT_COMPLETER_SCHED);
134
135 rxe_run_task(&qp->comp.task, must_sched);
136 }
137
get_wqe(struct rxe_qp * qp,struct rxe_pkt_info * pkt,struct rxe_send_wqe ** wqe_p)138 static inline enum comp_state get_wqe(struct rxe_qp *qp,
139 struct rxe_pkt_info *pkt,
140 struct rxe_send_wqe **wqe_p)
141 {
142 struct rxe_send_wqe *wqe;
143
144 /* we come here whether or not we found a response packet to see if
145 * there are any posted WQEs
146 */
147 wqe = queue_head(qp->sq.queue, QUEUE_TYPE_FROM_CLIENT);
148 *wqe_p = wqe;
149
150 /* no WQE or requester has not started it yet */
151 if (!wqe || wqe->state == wqe_state_posted)
152 return pkt ? COMPST_DONE : COMPST_EXIT;
153
154 /* WQE does not require an ack */
155 if (wqe->state == wqe_state_done)
156 return COMPST_COMP_WQE;
157
158 /* WQE caused an error */
159 if (wqe->state == wqe_state_error)
160 return COMPST_ERROR;
161
162 /* we have a WQE, if we also have an ack check its PSN */
163 return pkt ? COMPST_CHECK_PSN : COMPST_EXIT;
164 }
165
reset_retry_counters(struct rxe_qp * qp)166 static inline void reset_retry_counters(struct rxe_qp *qp)
167 {
168 qp->comp.retry_cnt = qp->attr.retry_cnt;
169 qp->comp.rnr_retry = qp->attr.rnr_retry;
170 qp->comp.started_retry = 0;
171 }
172
check_psn(struct rxe_qp * qp,struct rxe_pkt_info * pkt,struct rxe_send_wqe * wqe)173 static inline enum comp_state check_psn(struct rxe_qp *qp,
174 struct rxe_pkt_info *pkt,
175 struct rxe_send_wqe *wqe)
176 {
177 s32 diff;
178
179 /* check to see if response is past the oldest WQE. if it is, complete
180 * send/write or error read/atomic
181 */
182 diff = psn_compare(pkt->psn, wqe->last_psn);
183 if (diff > 0) {
184 if (wqe->state == wqe_state_pending) {
185 if (wqe->mask & WR_ATOMIC_OR_READ_MASK)
186 return COMPST_ERROR_RETRY;
187
188 reset_retry_counters(qp);
189 return COMPST_COMP_WQE;
190 } else {
191 return COMPST_DONE;
192 }
193 }
194
195 /* compare response packet to expected response */
196 diff = psn_compare(pkt->psn, qp->comp.psn);
197 if (diff < 0) {
198 /* response is most likely a retried packet if it matches an
199 * uncompleted WQE go complete it else ignore it
200 */
201 if (pkt->psn == wqe->last_psn)
202 return COMPST_COMP_ACK;
203 else
204 return COMPST_DONE;
205 } else if ((diff > 0) && (wqe->mask & WR_ATOMIC_OR_READ_MASK)) {
206 return COMPST_DONE;
207 } else {
208 return COMPST_CHECK_ACK;
209 }
210 }
211
check_ack(struct rxe_qp * qp,struct rxe_pkt_info * pkt,struct rxe_send_wqe * wqe)212 static inline enum comp_state check_ack(struct rxe_qp *qp,
213 struct rxe_pkt_info *pkt,
214 struct rxe_send_wqe *wqe)
215 {
216 unsigned int mask = pkt->mask;
217 u8 syn;
218 struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
219
220 /* Check the sequence only */
221 switch (qp->comp.opcode) {
222 case -1:
223 /* Will catch all *_ONLY cases. */
224 if (!(mask & RXE_START_MASK))
225 return COMPST_ERROR;
226
227 break;
228
229 case IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST:
230 case IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE:
231 if (pkt->opcode != IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE &&
232 pkt->opcode != IB_OPCODE_RC_RDMA_READ_RESPONSE_LAST) {
233 /* read retries of partial data may restart from
234 * read response first or response only.
235 */
236 if ((pkt->psn == wqe->first_psn &&
237 pkt->opcode ==
238 IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST) ||
239 (wqe->first_psn == wqe->last_psn &&
240 pkt->opcode ==
241 IB_OPCODE_RC_RDMA_READ_RESPONSE_ONLY))
242 break;
243
244 return COMPST_ERROR;
245 }
246 break;
247 default:
248 WARN_ON_ONCE(1);
249 }
250
251 /* Check operation validity. */
252 switch (pkt->opcode) {
253 case IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST:
254 case IB_OPCODE_RC_RDMA_READ_RESPONSE_LAST:
255 case IB_OPCODE_RC_RDMA_READ_RESPONSE_ONLY:
256 syn = aeth_syn(pkt);
257
258 if ((syn & AETH_TYPE_MASK) != AETH_ACK)
259 return COMPST_ERROR;
260
261 fallthrough;
262 /* (IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE doesn't have an AETH)
263 */
264 case IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE:
265 if (wqe->wr.opcode != IB_WR_RDMA_READ &&
266 wqe->wr.opcode != IB_WR_RDMA_READ_WITH_INV) {
267 wqe->status = IB_WC_FATAL_ERR;
268 return COMPST_ERROR;
269 }
270 reset_retry_counters(qp);
271 return COMPST_READ;
272
273 case IB_OPCODE_RC_ATOMIC_ACKNOWLEDGE:
274 syn = aeth_syn(pkt);
275
276 if ((syn & AETH_TYPE_MASK) != AETH_ACK)
277 return COMPST_ERROR;
278
279 if (wqe->wr.opcode != IB_WR_ATOMIC_CMP_AND_SWP &&
280 wqe->wr.opcode != IB_WR_ATOMIC_FETCH_AND_ADD)
281 return COMPST_ERROR;
282 reset_retry_counters(qp);
283 return COMPST_ATOMIC;
284
285 case IB_OPCODE_RC_ACKNOWLEDGE:
286 syn = aeth_syn(pkt);
287 switch (syn & AETH_TYPE_MASK) {
288 case AETH_ACK:
289 reset_retry_counters(qp);
290 return COMPST_WRITE_SEND;
291
292 case AETH_RNR_NAK:
293 rxe_counter_inc(rxe, RXE_CNT_RCV_RNR);
294 return COMPST_RNR_RETRY;
295
296 case AETH_NAK:
297 switch (syn) {
298 case AETH_NAK_PSN_SEQ_ERROR:
299 /* a nak implicitly acks all packets with psns
300 * before
301 */
302 if (psn_compare(pkt->psn, qp->comp.psn) > 0) {
303 rxe_counter_inc(rxe,
304 RXE_CNT_RCV_SEQ_ERR);
305 qp->comp.psn = pkt->psn;
306 if (qp->req.wait_psn) {
307 qp->req.wait_psn = 0;
308 rxe_run_task(&qp->req.task, 0);
309 }
310 }
311 return COMPST_ERROR_RETRY;
312
313 case AETH_NAK_INVALID_REQ:
314 wqe->status = IB_WC_REM_INV_REQ_ERR;
315 return COMPST_ERROR;
316
317 case AETH_NAK_REM_ACC_ERR:
318 wqe->status = IB_WC_REM_ACCESS_ERR;
319 return COMPST_ERROR;
320
321 case AETH_NAK_REM_OP_ERR:
322 wqe->status = IB_WC_REM_OP_ERR;
323 return COMPST_ERROR;
324
325 default:
326 pr_warn("unexpected nak %x\n", syn);
327 wqe->status = IB_WC_REM_OP_ERR;
328 return COMPST_ERROR;
329 }
330
331 default:
332 return COMPST_ERROR;
333 }
334 break;
335
336 default:
337 pr_warn("unexpected opcode\n");
338 }
339
340 return COMPST_ERROR;
341 }
342
do_read(struct rxe_qp * qp,struct rxe_pkt_info * pkt,struct rxe_send_wqe * wqe)343 static inline enum comp_state do_read(struct rxe_qp *qp,
344 struct rxe_pkt_info *pkt,
345 struct rxe_send_wqe *wqe)
346 {
347 int ret;
348
349 ret = copy_data(qp->pd, IB_ACCESS_LOCAL_WRITE,
350 &wqe->dma, payload_addr(pkt),
351 payload_size(pkt), RXE_TO_MR_OBJ);
352 if (ret) {
353 wqe->status = IB_WC_LOC_PROT_ERR;
354 return COMPST_ERROR;
355 }
356
357 if (wqe->dma.resid == 0 && (pkt->mask & RXE_END_MASK))
358 return COMPST_COMP_ACK;
359
360 return COMPST_UPDATE_COMP;
361 }
362
do_atomic(struct rxe_qp * qp,struct rxe_pkt_info * pkt,struct rxe_send_wqe * wqe)363 static inline enum comp_state do_atomic(struct rxe_qp *qp,
364 struct rxe_pkt_info *pkt,
365 struct rxe_send_wqe *wqe)
366 {
367 int ret;
368
369 u64 atomic_orig = atmack_orig(pkt);
370
371 ret = copy_data(qp->pd, IB_ACCESS_LOCAL_WRITE,
372 &wqe->dma, &atomic_orig,
373 sizeof(u64), RXE_TO_MR_OBJ);
374 if (ret) {
375 wqe->status = IB_WC_LOC_PROT_ERR;
376 return COMPST_ERROR;
377 }
378
379 return COMPST_COMP_ACK;
380 }
381
make_send_cqe(struct rxe_qp * qp,struct rxe_send_wqe * wqe,struct rxe_cqe * cqe)382 static void make_send_cqe(struct rxe_qp *qp, struct rxe_send_wqe *wqe,
383 struct rxe_cqe *cqe)
384 {
385 struct ib_wc *wc = &cqe->ibwc;
386 struct ib_uverbs_wc *uwc = &cqe->uibwc;
387
388 memset(cqe, 0, sizeof(*cqe));
389
390 if (!qp->is_user) {
391 wc->wr_id = wqe->wr.wr_id;
392 wc->status = wqe->status;
393 wc->qp = &qp->ibqp;
394 } else {
395 uwc->wr_id = wqe->wr.wr_id;
396 uwc->status = wqe->status;
397 uwc->qp_num = qp->ibqp.qp_num;
398 }
399
400 if (wqe->status == IB_WC_SUCCESS) {
401 if (!qp->is_user) {
402 wc->opcode = wr_to_wc_opcode(wqe->wr.opcode);
403 if (wqe->wr.opcode == IB_WR_RDMA_WRITE_WITH_IMM ||
404 wqe->wr.opcode == IB_WR_SEND_WITH_IMM)
405 wc->wc_flags = IB_WC_WITH_IMM;
406 wc->byte_len = wqe->dma.length;
407 } else {
408 uwc->opcode = wr_to_wc_opcode(wqe->wr.opcode);
409 if (wqe->wr.opcode == IB_WR_RDMA_WRITE_WITH_IMM ||
410 wqe->wr.opcode == IB_WR_SEND_WITH_IMM)
411 uwc->wc_flags = IB_WC_WITH_IMM;
412 uwc->byte_len = wqe->dma.length;
413 }
414 }
415 }
416
417 /*
418 * IBA Spec. Section 10.7.3.1 SIGNALED COMPLETIONS
419 * ---------8<---------8<-------------
420 * ...Note that if a completion error occurs, a Work Completion
421 * will always be generated, even if the signaling
422 * indicator requests an Unsignaled Completion.
423 * ---------8<---------8<-------------
424 */
do_complete(struct rxe_qp * qp,struct rxe_send_wqe * wqe)425 static void do_complete(struct rxe_qp *qp, struct rxe_send_wqe *wqe)
426 {
427 struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
428 struct rxe_cqe cqe;
429 bool post;
430
431 /* do we need to post a completion */
432 post = ((qp->sq_sig_type == IB_SIGNAL_ALL_WR) ||
433 (wqe->wr.send_flags & IB_SEND_SIGNALED) ||
434 wqe->status != IB_WC_SUCCESS);
435
436 if (post)
437 make_send_cqe(qp, wqe, &cqe);
438
439 queue_advance_consumer(qp->sq.queue, QUEUE_TYPE_FROM_CLIENT);
440
441 if (post)
442 rxe_cq_post(qp->scq, &cqe, 0);
443
444 if (wqe->wr.opcode == IB_WR_SEND ||
445 wqe->wr.opcode == IB_WR_SEND_WITH_IMM ||
446 wqe->wr.opcode == IB_WR_SEND_WITH_INV)
447 rxe_counter_inc(rxe, RXE_CNT_RDMA_SEND);
448
449 /*
450 * we completed something so let req run again
451 * if it is trying to fence
452 */
453 if (qp->req.wait_fence) {
454 qp->req.wait_fence = 0;
455 rxe_run_task(&qp->req.task, 0);
456 }
457 }
458
complete_ack(struct rxe_qp * qp,struct rxe_pkt_info * pkt,struct rxe_send_wqe * wqe)459 static inline enum comp_state complete_ack(struct rxe_qp *qp,
460 struct rxe_pkt_info *pkt,
461 struct rxe_send_wqe *wqe)
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_bh(&qp->state_lock);
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_bh(&qp->state_lock);
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_bh(&qp->state_lock);
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_put(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_put(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;
566
567 if (!rxe_get(qp))
568 return -EAGAIN;
569
570 if (!qp->valid || qp->comp.state == QP_STATE_ERROR ||
571 qp->comp.state == QP_STATE_RESET) {
572 rxe_drain_resp_pkts(qp, qp->valid &&
573 qp->comp.state == QP_STATE_ERROR);
574 goto exit;
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 goto exit;
586
587 state = COMPST_GET_ACK;
588
589 while (1) {
590 pr_debug("qp#%d state = %s\n", qp_num(qp),
591 comp_state_name[state]);
592 switch (state) {
593 case COMPST_GET_ACK:
594 skb = skb_dequeue(&qp->resp_pkts);
595 if (skb) {
596 pkt = SKB_TO_PKT(skb);
597 qp->comp.timeout_retry = 0;
598 }
599 state = COMPST_GET_WQE;
600 break;
601
602 case COMPST_GET_WQE:
603 state = get_wqe(qp, pkt, &wqe);
604 break;
605
606 case COMPST_CHECK_PSN:
607 state = check_psn(qp, pkt, wqe);
608 break;
609
610 case COMPST_CHECK_ACK:
611 state = check_ack(qp, pkt, wqe);
612 break;
613
614 case COMPST_READ:
615 state = do_read(qp, pkt, wqe);
616 break;
617
618 case COMPST_ATOMIC:
619 state = do_atomic(qp, pkt, wqe);
620 break;
621
622 case COMPST_WRITE_SEND:
623 if (wqe->state == wqe_state_pending &&
624 wqe->last_psn == pkt->psn)
625 state = COMPST_COMP_ACK;
626 else
627 state = COMPST_UPDATE_COMP;
628 break;
629
630 case COMPST_COMP_ACK:
631 state = complete_ack(qp, pkt, wqe);
632 break;
633
634 case COMPST_COMP_WQE:
635 state = complete_wqe(qp, pkt, wqe);
636 break;
637
638 case COMPST_UPDATE_COMP:
639 if (pkt->mask & RXE_END_MASK)
640 qp->comp.opcode = -1;
641 else
642 qp->comp.opcode = pkt->opcode;
643
644 if (psn_compare(pkt->psn, qp->comp.psn) >= 0)
645 qp->comp.psn = (pkt->psn + 1) & BTH_PSN_MASK;
646
647 if (qp->req.wait_psn) {
648 qp->req.wait_psn = 0;
649 rxe_run_task(&qp->req.task, 1);
650 }
651
652 state = COMPST_DONE;
653 break;
654
655 case COMPST_DONE:
656 goto done;
657
658 case COMPST_EXIT:
659 if (qp->comp.timeout_retry && wqe) {
660 state = COMPST_ERROR_RETRY;
661 break;
662 }
663
664 /* re reset the timeout counter if
665 * (1) QP is type RC
666 * (2) the QP is alive
667 * (3) there is a packet sent by the requester that
668 * might be acked (we still might get spurious
669 * timeouts but try to keep them as few as possible)
670 * (4) the timeout parameter is set
671 */
672 if ((qp_type(qp) == IB_QPT_RC) &&
673 (qp->req.state == QP_STATE_READY) &&
674 (psn_compare(qp->req.psn, qp->comp.psn) > 0) &&
675 qp->qp_timeout_jiffies)
676 mod_timer(&qp->retrans_timer,
677 jiffies + qp->qp_timeout_jiffies);
678 goto exit;
679
680 case COMPST_ERROR_RETRY:
681 /* we come here if the retry timer fired and we did
682 * not receive a response packet. try to retry the send
683 * queue if that makes sense and the limits have not
684 * been exceeded. remember that some timeouts are
685 * spurious since we do not reset the timer but kick
686 * it down the road or let it expire
687 */
688
689 /* there is nothing to retry in this case */
690 if (!wqe || (wqe->state == wqe_state_posted))
691 goto exit;
692
693 /* if we've started a retry, don't start another
694 * retry sequence, unless this is a timeout.
695 */
696 if (qp->comp.started_retry &&
697 !qp->comp.timeout_retry)
698 goto done;
699
700 if (qp->comp.retry_cnt > 0) {
701 if (qp->comp.retry_cnt != 7)
702 qp->comp.retry_cnt--;
703
704 /* no point in retrying if we have already
705 * seen the last ack that the requester could
706 * have caused
707 */
708 if (psn_compare(qp->req.psn,
709 qp->comp.psn) > 0) {
710 /* tell the requester to retry the
711 * send queue next time around
712 */
713 rxe_counter_inc(rxe,
714 RXE_CNT_COMP_RETRY);
715 qp->req.need_retry = 1;
716 qp->comp.started_retry = 1;
717 rxe_run_task(&qp->req.task, 0);
718 }
719 goto done;
720
721 } else {
722 rxe_counter_inc(rxe, RXE_CNT_RETRY_EXCEEDED);
723 wqe->status = IB_WC_RETRY_EXC_ERR;
724 state = COMPST_ERROR;
725 }
726 break;
727
728 case COMPST_RNR_RETRY:
729 /* we come here if we received an RNR NAK */
730 if (qp->comp.rnr_retry > 0) {
731 if (qp->comp.rnr_retry != 7)
732 qp->comp.rnr_retry--;
733
734 /* don't start a retry flow until the
735 * rnr timer has fired
736 */
737 qp->req.wait_for_rnr_timer = 1;
738 pr_debug("qp#%d set rnr nak timer\n",
739 qp_num(qp));
740 mod_timer(&qp->rnr_nak_timer,
741 jiffies + rnrnak_jiffies(aeth_syn(pkt)
742 & ~AETH_TYPE_MASK));
743 goto exit;
744 } else {
745 rxe_counter_inc(rxe,
746 RXE_CNT_RNR_RETRY_EXCEEDED);
747 wqe->status = IB_WC_RNR_RETRY_EXC_ERR;
748 state = COMPST_ERROR;
749 }
750 break;
751
752 case COMPST_ERROR:
753 WARN_ON_ONCE(wqe->status == IB_WC_SUCCESS);
754 do_complete(qp, wqe);
755 rxe_qp_error(qp);
756 goto exit;
757 }
758 }
759
760 /* A non-zero return value will cause rxe_do_task to
761 * exit its loop and end the tasklet. A zero return
762 * will continue looping and return to rxe_completer
763 */
764 done:
765 ret = 0;
766 goto out;
767 exit:
768 ret = -EAGAIN;
769 out:
770 if (pkt)
771 free_pkt(pkt);
772 rxe_put(qp);
773
774 return ret;
775 }
776