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
14enum 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
32static 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
50static 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
85static inline unsigned long rnrnak_jiffies(u8 timeout)
86{
87 return max_t(unsigned long,
88 usecs_to_jiffies(rnrnak_usec[timeout]), 1);
89}
90
91static 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 case IB_WR_ATOMIC_WRITE: return IB_WC_ATOMIC_WRITE;
108 case IB_WR_FLUSH: return IB_WC_FLUSH;
109
110 default:
111 return 0xff;
112 }
113}
114
115void retransmit_timer(struct timer_list *t)
116{
117 struct rxe_qp *qp = from_timer(qp, t, retrans_timer);
118 unsigned long flags;
119
120 rxe_dbg_qp(qp, "retransmit timer fired\n");
121
122 spin_lock_irqsave(&qp->state_lock, flags);
123 if (qp->valid) {
124 qp->comp.timeout = 1;
125 rxe_sched_task(task: &qp->comp.task);
126 }
127 spin_unlock_irqrestore(lock: &qp->state_lock, flags);
128}
129
130void rxe_comp_queue_pkt(struct rxe_qp *qp, struct sk_buff *skb)
131{
132 int must_sched;
133
134 skb_queue_tail(list: &qp->resp_pkts, newsk: skb);
135
136 must_sched = skb_queue_len(list_: &qp->resp_pkts) > 1;
137 if (must_sched != 0)
138 rxe_counter_inc(rxe: SKB_TO_PKT(skb)->rxe, index: RXE_CNT_COMPLETER_SCHED);
139
140 if (must_sched)
141 rxe_sched_task(task: &qp->comp.task);
142 else
143 rxe_run_task(task: &qp->comp.task);
144}
145
146static inline enum comp_state get_wqe(struct rxe_qp *qp,
147 struct rxe_pkt_info *pkt,
148 struct rxe_send_wqe **wqe_p)
149{
150 struct rxe_send_wqe *wqe;
151
152 /* we come here whether or not we found a response packet to see if
153 * there are any posted WQEs
154 */
155 wqe = queue_head(q: qp->sq.queue, type: QUEUE_TYPE_FROM_CLIENT);
156 *wqe_p = wqe;
157
158 /* no WQE or requester has not started it yet */
159 if (!wqe || wqe->state == wqe_state_posted)
160 return pkt ? COMPST_DONE : COMPST_EXIT;
161
162 /* WQE does not require an ack */
163 if (wqe->state == wqe_state_done)
164 return COMPST_COMP_WQE;
165
166 /* WQE caused an error */
167 if (wqe->state == wqe_state_error)
168 return COMPST_ERROR;
169
170 /* we have a WQE, if we also have an ack check its PSN */
171 return pkt ? COMPST_CHECK_PSN : COMPST_EXIT;
172}
173
174static inline void reset_retry_counters(struct rxe_qp *qp)
175{
176 qp->comp.retry_cnt = qp->attr.retry_cnt;
177 qp->comp.rnr_retry = qp->attr.rnr_retry;
178 qp->comp.started_retry = 0;
179}
180
181static inline enum comp_state check_psn(struct rxe_qp *qp,
182 struct rxe_pkt_info *pkt,
183 struct rxe_send_wqe *wqe)
184{
185 s32 diff;
186
187 /* check to see if response is past the oldest WQE. if it is, complete
188 * send/write or error read/atomic
189 */
190 diff = psn_compare(psn_a: pkt->psn, psn_b: wqe->last_psn);
191 if (diff > 0) {
192 if (wqe->state == wqe_state_pending) {
193 if (wqe->mask & WR_ATOMIC_OR_READ_MASK)
194 return COMPST_ERROR_RETRY;
195
196 reset_retry_counters(qp);
197 return COMPST_COMP_WQE;
198 } else {
199 return COMPST_DONE;
200 }
201 }
202
203 /* compare response packet to expected response */
204 diff = psn_compare(psn_a: pkt->psn, psn_b: qp->comp.psn);
205 if (diff < 0) {
206 /* response is most likely a retried packet if it matches an
207 * uncompleted WQE go complete it else ignore it
208 */
209 if (pkt->psn == wqe->last_psn)
210 return COMPST_COMP_ACK;
211 else if (pkt->opcode == IB_OPCODE_RC_ACKNOWLEDGE &&
212 (qp->comp.opcode == IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST ||
213 qp->comp.opcode == IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE))
214 return COMPST_CHECK_ACK;
215 else
216 return COMPST_DONE;
217 } else if ((diff > 0) && (wqe->mask & WR_ATOMIC_OR_READ_MASK)) {
218 return COMPST_DONE;
219 } else {
220 return COMPST_CHECK_ACK;
221 }
222}
223
224static inline enum comp_state check_ack(struct rxe_qp *qp,
225 struct rxe_pkt_info *pkt,
226 struct rxe_send_wqe *wqe)
227{
228 unsigned int mask = pkt->mask;
229 u8 syn;
230 struct rxe_dev *rxe = to_rdev(dev: qp->ibqp.device);
231
232 /* Check the sequence only */
233 switch (qp->comp.opcode) {
234 case -1:
235 /* Will catch all *_ONLY cases. */
236 if (!(mask & RXE_START_MASK))
237 return COMPST_ERROR;
238
239 break;
240
241 case IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST:
242 case IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE:
243 /* Check NAK code to handle a remote error */
244 if (pkt->opcode == IB_OPCODE_RC_ACKNOWLEDGE)
245 break;
246
247 if (pkt->opcode != IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE &&
248 pkt->opcode != IB_OPCODE_RC_RDMA_READ_RESPONSE_LAST) {
249 /* read retries of partial data may restart from
250 * read response first or response only.
251 */
252 if ((pkt->psn == wqe->first_psn &&
253 pkt->opcode ==
254 IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST) ||
255 (wqe->first_psn == wqe->last_psn &&
256 pkt->opcode ==
257 IB_OPCODE_RC_RDMA_READ_RESPONSE_ONLY))
258 break;
259
260 return COMPST_ERROR;
261 }
262 break;
263 default:
264 WARN_ON_ONCE(1);
265 }
266
267 /* Check operation validity. */
268 switch (pkt->opcode) {
269 case IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST:
270 case IB_OPCODE_RC_RDMA_READ_RESPONSE_LAST:
271 case IB_OPCODE_RC_RDMA_READ_RESPONSE_ONLY:
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_WRITE)
278 return COMPST_WRITE_SEND;
279
280 fallthrough;
281 /* (IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE doesn't have an AETH)
282 */
283 case IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE:
284 if (wqe->wr.opcode != IB_WR_RDMA_READ &&
285 wqe->wr.opcode != IB_WR_RDMA_READ_WITH_INV &&
286 wqe->wr.opcode != IB_WR_FLUSH) {
287 wqe->status = IB_WC_FATAL_ERR;
288 return COMPST_ERROR;
289 }
290 reset_retry_counters(qp);
291 return COMPST_READ;
292
293 case IB_OPCODE_RC_ATOMIC_ACKNOWLEDGE:
294 syn = aeth_syn(pkt);
295
296 if ((syn & AETH_TYPE_MASK) != AETH_ACK)
297 return COMPST_ERROR;
298
299 if (wqe->wr.opcode != IB_WR_ATOMIC_CMP_AND_SWP &&
300 wqe->wr.opcode != IB_WR_ATOMIC_FETCH_AND_ADD)
301 return COMPST_ERROR;
302 reset_retry_counters(qp);
303 return COMPST_ATOMIC;
304
305 case IB_OPCODE_RC_ACKNOWLEDGE:
306 syn = aeth_syn(pkt);
307 switch (syn & AETH_TYPE_MASK) {
308 case AETH_ACK:
309 reset_retry_counters(qp);
310 return COMPST_WRITE_SEND;
311
312 case AETH_RNR_NAK:
313 rxe_counter_inc(rxe, index: RXE_CNT_RCV_RNR);
314 return COMPST_RNR_RETRY;
315
316 case AETH_NAK:
317 switch (syn) {
318 case AETH_NAK_PSN_SEQ_ERROR:
319 /* a nak implicitly acks all packets with psns
320 * before
321 */
322 if (psn_compare(psn_a: pkt->psn, psn_b: qp->comp.psn) > 0) {
323 rxe_counter_inc(rxe,
324 index: RXE_CNT_RCV_SEQ_ERR);
325 qp->comp.psn = pkt->psn;
326 if (qp->req.wait_psn) {
327 qp->req.wait_psn = 0;
328 rxe_sched_task(task: &qp->req.task);
329 }
330 }
331 return COMPST_ERROR_RETRY;
332
333 case AETH_NAK_INVALID_REQ:
334 wqe->status = IB_WC_REM_INV_REQ_ERR;
335 return COMPST_ERROR;
336
337 case AETH_NAK_REM_ACC_ERR:
338 wqe->status = IB_WC_REM_ACCESS_ERR;
339 return COMPST_ERROR;
340
341 case AETH_NAK_REM_OP_ERR:
342 wqe->status = IB_WC_REM_OP_ERR;
343 return COMPST_ERROR;
344
345 default:
346 rxe_dbg_qp(qp, "unexpected nak %x\n", syn);
347 wqe->status = IB_WC_REM_OP_ERR;
348 return COMPST_ERROR;
349 }
350
351 default:
352 return COMPST_ERROR;
353 }
354 break;
355
356 default:
357 rxe_dbg_qp(qp, "unexpected opcode\n");
358 }
359
360 return COMPST_ERROR;
361}
362
363static inline enum comp_state do_read(struct rxe_qp *qp,
364 struct rxe_pkt_info *pkt,
365 struct rxe_send_wqe *wqe)
366{
367 int ret;
368
369 ret = copy_data(pd: qp->pd, access: IB_ACCESS_LOCAL_WRITE,
370 dma: &wqe->dma, addr: payload_addr(pkt),
371 length: payload_size(pkt), dir: RXE_TO_MR_OBJ);
372 if (ret) {
373 wqe->status = IB_WC_LOC_PROT_ERR;
374 return COMPST_ERROR;
375 }
376
377 if (wqe->dma.resid == 0 && (pkt->mask & RXE_END_MASK))
378 return COMPST_COMP_ACK;
379
380 return COMPST_UPDATE_COMP;
381}
382
383static inline enum comp_state do_atomic(struct rxe_qp *qp,
384 struct rxe_pkt_info *pkt,
385 struct rxe_send_wqe *wqe)
386{
387 int ret;
388
389 u64 atomic_orig = atmack_orig(pkt);
390
391 ret = copy_data(pd: qp->pd, access: IB_ACCESS_LOCAL_WRITE,
392 dma: &wqe->dma, addr: &atomic_orig,
393 length: sizeof(u64), dir: RXE_TO_MR_OBJ);
394 if (ret) {
395 wqe->status = IB_WC_LOC_PROT_ERR;
396 return COMPST_ERROR;
397 }
398
399 return COMPST_COMP_ACK;
400}
401
402static void make_send_cqe(struct rxe_qp *qp, struct rxe_send_wqe *wqe,
403 struct rxe_cqe *cqe)
404{
405 struct ib_wc *wc = &cqe->ibwc;
406 struct ib_uverbs_wc *uwc = &cqe->uibwc;
407
408 memset(cqe, 0, sizeof(*cqe));
409
410 if (!qp->is_user) {
411 wc->wr_id = wqe->wr.wr_id;
412 wc->status = wqe->status;
413 wc->qp = &qp->ibqp;
414 } else {
415 uwc->wr_id = wqe->wr.wr_id;
416 uwc->status = wqe->status;
417 uwc->qp_num = qp->ibqp.qp_num;
418 }
419
420 if (wqe->status == IB_WC_SUCCESS) {
421 if (!qp->is_user) {
422 wc->opcode = wr_to_wc_opcode(opcode: wqe->wr.opcode);
423 if (wqe->wr.opcode == IB_WR_RDMA_WRITE_WITH_IMM ||
424 wqe->wr.opcode == IB_WR_SEND_WITH_IMM)
425 wc->wc_flags = IB_WC_WITH_IMM;
426 wc->byte_len = wqe->dma.length;
427 } else {
428 uwc->opcode = wr_to_wc_opcode(opcode: wqe->wr.opcode);
429 if (wqe->wr.opcode == IB_WR_RDMA_WRITE_WITH_IMM ||
430 wqe->wr.opcode == IB_WR_SEND_WITH_IMM)
431 uwc->wc_flags = IB_WC_WITH_IMM;
432 uwc->byte_len = wqe->dma.length;
433 }
434 } else {
435 if (wqe->status != IB_WC_WR_FLUSH_ERR)
436 rxe_err_qp(qp, "non-flush error status = %d\n",
437 wqe->status);
438 }
439}
440
441/*
442 * IBA Spec. Section 10.7.3.1 SIGNALED COMPLETIONS
443 * ---------8<---------8<-------------
444 * ...Note that if a completion error occurs, a Work Completion
445 * will always be generated, even if the signaling
446 * indicator requests an Unsignaled Completion.
447 * ---------8<---------8<-------------
448 */
449static void do_complete(struct rxe_qp *qp, struct rxe_send_wqe *wqe)
450{
451 struct rxe_dev *rxe = to_rdev(dev: qp->ibqp.device);
452 struct rxe_cqe cqe;
453 bool post;
454
455 /* do we need to post a completion */
456 post = ((qp->sq_sig_type == IB_SIGNAL_ALL_WR) ||
457 (wqe->wr.send_flags & IB_SEND_SIGNALED) ||
458 wqe->status != IB_WC_SUCCESS);
459
460 if (post)
461 make_send_cqe(qp, wqe, cqe: &cqe);
462
463 queue_advance_consumer(q: qp->sq.queue, type: QUEUE_TYPE_FROM_CLIENT);
464
465 if (post)
466 rxe_cq_post(cq: qp->scq, cqe: &cqe, solicited: 0);
467
468 if (wqe->wr.opcode == IB_WR_SEND ||
469 wqe->wr.opcode == IB_WR_SEND_WITH_IMM ||
470 wqe->wr.opcode == IB_WR_SEND_WITH_INV)
471 rxe_counter_inc(rxe, index: RXE_CNT_RDMA_SEND);
472
473 /*
474 * we completed something so let req run again
475 * if it is trying to fence
476 */
477 if (qp->req.wait_fence) {
478 qp->req.wait_fence = 0;
479 rxe_sched_task(task: &qp->req.task);
480 }
481}
482
483static void comp_check_sq_drain_done(struct rxe_qp *qp)
484{
485 unsigned long flags;
486
487 spin_lock_irqsave(&qp->state_lock, flags);
488 if (unlikely(qp_state(qp) == IB_QPS_SQD)) {
489 if (qp->attr.sq_draining && qp->comp.psn == qp->req.psn) {
490 qp->attr.sq_draining = 0;
491 spin_unlock_irqrestore(lock: &qp->state_lock, flags);
492
493 if (qp->ibqp.event_handler) {
494 struct ib_event ev;
495
496 ev.device = qp->ibqp.device;
497 ev.element.qp = &qp->ibqp;
498 ev.event = IB_EVENT_SQ_DRAINED;
499 qp->ibqp.event_handler(&ev,
500 qp->ibqp.qp_context);
501 }
502 return;
503 }
504 }
505 spin_unlock_irqrestore(lock: &qp->state_lock, flags);
506}
507
508static inline enum comp_state complete_ack(struct rxe_qp *qp,
509 struct rxe_pkt_info *pkt,
510 struct rxe_send_wqe *wqe)
511{
512 if (wqe->has_rd_atomic) {
513 wqe->has_rd_atomic = 0;
514 atomic_inc(v: &qp->req.rd_atomic);
515 if (qp->req.need_rd_atomic) {
516 qp->comp.timeout_retry = 0;
517 qp->req.need_rd_atomic = 0;
518 rxe_sched_task(task: &qp->req.task);
519 }
520 }
521
522 comp_check_sq_drain_done(qp);
523
524 do_complete(qp, wqe);
525
526 if (psn_compare(psn_a: pkt->psn, psn_b: qp->comp.psn) >= 0)
527 return COMPST_UPDATE_COMP;
528 else
529 return COMPST_DONE;
530}
531
532static inline enum comp_state complete_wqe(struct rxe_qp *qp,
533 struct rxe_pkt_info *pkt,
534 struct rxe_send_wqe *wqe)
535{
536 if (pkt && wqe->state == wqe_state_pending) {
537 if (psn_compare(psn_a: wqe->last_psn, psn_b: qp->comp.psn) >= 0) {
538 qp->comp.psn = (wqe->last_psn + 1) & BTH_PSN_MASK;
539 qp->comp.opcode = -1;
540 }
541
542 if (qp->req.wait_psn) {
543 qp->req.wait_psn = 0;
544 rxe_sched_task(task: &qp->req.task);
545 }
546 }
547
548 do_complete(qp, wqe);
549
550 return COMPST_GET_WQE;
551}
552
553/* drain incoming response packet queue */
554static void drain_resp_pkts(struct rxe_qp *qp)
555{
556 struct sk_buff *skb;
557
558 while ((skb = skb_dequeue(list: &qp->resp_pkts))) {
559 rxe_put(qp);
560 kfree_skb(skb);
561 ib_device_put(device: qp->ibqp.device);
562 }
563}
564
565/* complete send wqe with flush error */
566static int flush_send_wqe(struct rxe_qp *qp, struct rxe_send_wqe *wqe)
567{
568 struct rxe_cqe cqe = {};
569 struct ib_wc *wc = &cqe.ibwc;
570 struct ib_uverbs_wc *uwc = &cqe.uibwc;
571 int err;
572
573 if (qp->is_user) {
574 uwc->wr_id = wqe->wr.wr_id;
575 uwc->status = IB_WC_WR_FLUSH_ERR;
576 uwc->qp_num = qp->ibqp.qp_num;
577 } else {
578 wc->wr_id = wqe->wr.wr_id;
579 wc->status = IB_WC_WR_FLUSH_ERR;
580 wc->qp = &qp->ibqp;
581 }
582
583 err = rxe_cq_post(cq: qp->scq, cqe: &cqe, solicited: 0);
584 if (err)
585 rxe_dbg_cq(qp->scq, "post cq failed, err = %d\n", err);
586
587 return err;
588}
589
590/* drain and optionally complete the send queue
591 * if unable to complete a wqe, i.e. cq is full, stop
592 * completing and flush the remaining wqes
593 */
594static void flush_send_queue(struct rxe_qp *qp, bool notify)
595{
596 struct rxe_send_wqe *wqe;
597 struct rxe_queue *q = qp->sq.queue;
598 int err;
599
600 /* send queue never got created. nothing to do. */
601 if (!qp->sq.queue)
602 return;
603
604 while ((wqe = queue_head(q, type: q->type))) {
605 if (notify) {
606 err = flush_send_wqe(qp, wqe);
607 if (err)
608 notify = 0;
609 }
610 queue_advance_consumer(q, type: q->type);
611 }
612}
613
614static void free_pkt(struct rxe_pkt_info *pkt)
615{
616 struct sk_buff *skb = PKT_TO_SKB(pkt);
617 struct rxe_qp *qp = pkt->qp;
618 struct ib_device *dev = qp->ibqp.device;
619
620 kfree_skb(skb);
621 rxe_put(qp);
622 ib_device_put(device: dev);
623}
624
625/* reset the retry timer if
626 * - QP is type RC
627 * - there is a packet sent by the requester that
628 * might be acked (we still might get spurious
629 * timeouts but try to keep them as few as possible)
630 * - the timeout parameter is set
631 * - the QP is alive
632 */
633static void reset_retry_timer(struct rxe_qp *qp)
634{
635 unsigned long flags;
636
637 if (qp_type(qp) == IB_QPT_RC && qp->qp_timeout_jiffies) {
638 spin_lock_irqsave(&qp->state_lock, flags);
639 if (qp_state(qp) >= IB_QPS_RTS &&
640 psn_compare(psn_a: qp->req.psn, psn_b: qp->comp.psn) > 0)
641 mod_timer(timer: &qp->retrans_timer,
642 expires: jiffies + qp->qp_timeout_jiffies);
643 spin_unlock_irqrestore(lock: &qp->state_lock, flags);
644 }
645}
646
647int rxe_completer(struct rxe_qp *qp)
648{
649 struct rxe_dev *rxe = to_rdev(dev: qp->ibqp.device);
650 struct rxe_send_wqe *wqe = NULL;
651 struct sk_buff *skb = NULL;
652 struct rxe_pkt_info *pkt = NULL;
653 enum comp_state state;
654 int ret;
655 unsigned long flags;
656
657 spin_lock_irqsave(&qp->state_lock, flags);
658 if (!qp->valid || qp_state(qp) == IB_QPS_ERR ||
659 qp_state(qp) == IB_QPS_RESET) {
660 bool notify = qp->valid && (qp_state(qp) == IB_QPS_ERR);
661
662 drain_resp_pkts(qp);
663 flush_send_queue(qp, notify);
664 spin_unlock_irqrestore(lock: &qp->state_lock, flags);
665 goto exit;
666 }
667 spin_unlock_irqrestore(lock: &qp->state_lock, flags);
668
669 if (qp->comp.timeout) {
670 qp->comp.timeout_retry = 1;
671 qp->comp.timeout = 0;
672 } else {
673 qp->comp.timeout_retry = 0;
674 }
675
676 if (qp->req.need_retry)
677 goto exit;
678
679 state = COMPST_GET_ACK;
680
681 while (1) {
682 rxe_dbg_qp(qp, "state = %s\n", comp_state_name[state]);
683 switch (state) {
684 case COMPST_GET_ACK:
685 skb = skb_dequeue(list: &qp->resp_pkts);
686 if (skb) {
687 pkt = SKB_TO_PKT(skb);
688 qp->comp.timeout_retry = 0;
689 }
690 state = COMPST_GET_WQE;
691 break;
692
693 case COMPST_GET_WQE:
694 state = get_wqe(qp, pkt, wqe_p: &wqe);
695 break;
696
697 case COMPST_CHECK_PSN:
698 state = check_psn(qp, pkt, wqe);
699 break;
700
701 case COMPST_CHECK_ACK:
702 state = check_ack(qp, pkt, wqe);
703 break;
704
705 case COMPST_READ:
706 state = do_read(qp, pkt, wqe);
707 break;
708
709 case COMPST_ATOMIC:
710 state = do_atomic(qp, pkt, wqe);
711 break;
712
713 case COMPST_WRITE_SEND:
714 if (wqe->state == wqe_state_pending &&
715 wqe->last_psn == pkt->psn)
716 state = COMPST_COMP_ACK;
717 else
718 state = COMPST_UPDATE_COMP;
719 break;
720
721 case COMPST_COMP_ACK:
722 state = complete_ack(qp, pkt, wqe);
723 break;
724
725 case COMPST_COMP_WQE:
726 state = complete_wqe(qp, pkt, wqe);
727 break;
728
729 case COMPST_UPDATE_COMP:
730 if (pkt->mask & RXE_END_MASK)
731 qp->comp.opcode = -1;
732 else
733 qp->comp.opcode = pkt->opcode;
734
735 if (psn_compare(psn_a: pkt->psn, psn_b: qp->comp.psn) >= 0)
736 qp->comp.psn = (pkt->psn + 1) & BTH_PSN_MASK;
737
738 if (qp->req.wait_psn) {
739 qp->req.wait_psn = 0;
740 rxe_sched_task(task: &qp->req.task);
741 }
742
743 state = COMPST_DONE;
744 break;
745
746 case COMPST_DONE:
747 goto done;
748
749 case COMPST_EXIT:
750 if (qp->comp.timeout_retry && wqe) {
751 state = COMPST_ERROR_RETRY;
752 break;
753 }
754
755 reset_retry_timer(qp);
756 goto exit;
757
758 case COMPST_ERROR_RETRY:
759 /* we come here if the retry timer fired and we did
760 * not receive a response packet. try to retry the send
761 * queue if that makes sense and the limits have not
762 * been exceeded. remember that some timeouts are
763 * spurious since we do not reset the timer but kick
764 * it down the road or let it expire
765 */
766
767 /* there is nothing to retry in this case */
768 if (!wqe || (wqe->state == wqe_state_posted))
769 goto exit;
770
771 /* if we've started a retry, don't start another
772 * retry sequence, unless this is a timeout.
773 */
774 if (qp->comp.started_retry &&
775 !qp->comp.timeout_retry)
776 goto done;
777
778 if (qp->comp.retry_cnt > 0) {
779 if (qp->comp.retry_cnt != 7)
780 qp->comp.retry_cnt--;
781
782 /* no point in retrying if we have already
783 * seen the last ack that the requester could
784 * have caused
785 */
786 if (psn_compare(psn_a: qp->req.psn,
787 psn_b: qp->comp.psn) > 0) {
788 /* tell the requester to retry the
789 * send queue next time around
790 */
791 rxe_counter_inc(rxe,
792 index: RXE_CNT_COMP_RETRY);
793 qp->req.need_retry = 1;
794 qp->comp.started_retry = 1;
795 rxe_sched_task(task: &qp->req.task);
796 }
797 goto done;
798
799 } else {
800 rxe_counter_inc(rxe, index: RXE_CNT_RETRY_EXCEEDED);
801 wqe->status = IB_WC_RETRY_EXC_ERR;
802 state = COMPST_ERROR;
803 }
804 break;
805
806 case COMPST_RNR_RETRY:
807 /* we come here if we received an RNR NAK */
808 if (qp->comp.rnr_retry > 0) {
809 if (qp->comp.rnr_retry != 7)
810 qp->comp.rnr_retry--;
811
812 /* don't start a retry flow until the
813 * rnr timer has fired
814 */
815 qp->req.wait_for_rnr_timer = 1;
816 rxe_dbg_qp(qp, "set rnr nak timer\n");
817 // TODO who protects from destroy_qp??
818 mod_timer(timer: &qp->rnr_nak_timer,
819 expires: jiffies + rnrnak_jiffies(timeout: aeth_syn(pkt)
820 & ~AETH_TYPE_MASK));
821 goto exit;
822 } else {
823 rxe_counter_inc(rxe,
824 index: RXE_CNT_RNR_RETRY_EXCEEDED);
825 wqe->status = IB_WC_RNR_RETRY_EXC_ERR;
826 state = COMPST_ERROR;
827 }
828 break;
829
830 case COMPST_ERROR:
831 WARN_ON_ONCE(wqe->status == IB_WC_SUCCESS);
832 do_complete(qp, wqe);
833 rxe_qp_error(qp);
834 goto exit;
835 }
836 }
837
838 /* A non-zero return value will cause rxe_do_task to
839 * exit its loop and end the work item. A zero return
840 * will continue looping and return to rxe_completer
841 */
842done:
843 ret = 0;
844 goto out;
845exit:
846 ret = -EAGAIN;
847out:
848 if (pkt)
849 free_pkt(pkt);
850 return ret;
851}
852

source code of linux/drivers/infiniband/sw/rxe/rxe_comp.c