drivers/infiniband/sw/rxe/rxe_comp.c

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