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         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
 115 void 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(&qp->comp.task);
 126         }
 127         spin_unlock_irqrestore(&qp->state_lock, flags);
 128 }
 129
 130 void rxe_comp_queue_pkt(struct rxe_qp *qp, struct sk_buff *skb)
 131 {
 132         int must_sched;
 133
 134         skb_queue_tail(&qp->resp_pkts, skb);
 135
 136         must_sched = skb_queue_len(&qp->resp_pkts) > 1;
 137         if (must_sched != 0)
 138                 rxe_counter_inc(SKB_TO_PKT(skb)->rxe, RXE_CNT_COMPLETER_SCHED);
 139
 140         if (must_sched)
 141                 rxe_sched_task(&qp->comp.task);
 142         else
 143                 rxe_run_task(&qp->comp.task);
 144 }
 145
 146 static 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(qp->sq.queue, 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
 174 static 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
 181 static 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(pkt->psn, 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(pkt->psn, 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
 224 static 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(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, 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(pkt->psn, qp->comp.psn) > 0) {
 323                                         rxe_counter_inc(rxe,
 324                                                         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(&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
 363 static 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(qp->pd, IB_ACCESS_LOCAL_WRITE,
 370                         &wqe->dma, payload_addr(pkt),
 371                         payload_size(pkt), 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
 383 static 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(qp->pd, IB_ACCESS_LOCAL_WRITE,
 392                         &wqe->dma, &atomic_orig,
 393                         sizeof(u64), 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
 402 static 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(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(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",
 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  */
 449 static void do_complete(struct rxe_qp *qp, struct rxe_send_wqe *wqe)
 450 {
 451         struct rxe_dev *rxe = to_rdev(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);
 462
 463         queue_advance_consumer(qp->sq.queue, QUEUE_TYPE_FROM_CLIENT);
 464
 465         if (post)
 466                 rxe_cq_post(qp->scq, &cqe, 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, 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(&qp->req.task);
 480         }
 481 }
 482
 483 static 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(&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(&qp->state_lock, flags);
 506 }
 507
 508 static 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(&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(&qp->req.task);
 519                 }
 520         }
 521
 522         comp_check_sq_drain_done(qp);
 523
 524         do_complete(qp, wqe);
 525
 526         if (psn_compare(pkt->psn, qp->comp.psn) >= 0)
 527                 return COMPST_UPDATE_COMP;
 528         else
 529                 return COMPST_DONE;
 530 }
 531
 532 static 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(wqe->last_psn, 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(&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 */
 554 static void drain_resp_pkts(struct rxe_qp *qp)
 555 {
 556         struct sk_buff *skb;
 557
 558         while ((skb = skb_dequeue(&qp->resp_pkts))) {
 559                 rxe_put(qp);
 560                 kfree_skb(skb);
 561                 ib_device_put(qp->ibqp.device);
 562         }
 563 }
 564
 565 /* complete send wqe with flush error */
 566 static 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(qp->scq, &cqe, 0);
 584         if (err)
 585                 rxe_dbg_cq(qp->scq, "post cq failed, err = %d", 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  */
 594 static 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         while ((wqe = queue_head(q, q->type))) {
 601                 if (notify) {
 602                         err = flush_send_wqe(qp, wqe);
 603                         if (err)
 604                                 notify = 0;
 605                 }
 606                 queue_advance_consumer(q, q->type);
 607         }
 608 }
 609
 610 static void free_pkt(struct rxe_pkt_info *pkt)
 611 {
 612         struct sk_buff *skb = PKT_TO_SKB(pkt);
 613         struct rxe_qp *qp = pkt->qp;
 614         struct ib_device *dev = qp->ibqp.device;
 615
 616         kfree_skb(skb);
 617         rxe_put(qp);
 618         ib_device_put(dev);
 619 }
 620
 621 /* reset the retry timer if
 622  * - QP is type RC
 623  * - there is a packet sent by the requester that
 624  *   might be acked (we still might get spurious
 625  *   timeouts but try to keep them as few as possible)
 626  * - the timeout parameter is set
 627  * - the QP is alive
 628  */
 629 static void reset_retry_timer(struct rxe_qp *qp)
 630 {
 631         unsigned long flags;
 632
 633         if (qp_type(qp) == IB_QPT_RC && qp->qp_timeout_jiffies) {
 634                 spin_lock_irqsave(&qp->state_lock, flags);
 635                 if (qp_state(qp) >= IB_QPS_RTS &&
 636                     psn_compare(qp->req.psn, qp->comp.psn) > 0)
 637                         mod_timer(&qp->retrans_timer,
 638                                   jiffies + qp->qp_timeout_jiffies);
 639                 spin_unlock_irqrestore(&qp->state_lock, flags);
 640         }
 641 }
 642
 643 int rxe_completer(struct rxe_qp *qp)
 644 {
 645         struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
 646         struct rxe_send_wqe *wqe = NULL;
 647         struct sk_buff *skb = NULL;
 648         struct rxe_pkt_info *pkt = NULL;
 649         enum comp_state state;
 650         int ret;
 651         unsigned long flags;
 652
 653         spin_lock_irqsave(&qp->state_lock, flags);
 654         if (!qp->valid || qp_state(qp) == IB_QPS_ERR ||
 655                           qp_state(qp) == IB_QPS_RESET) {
 656                 bool notify = qp->valid && (qp_state(qp) == IB_QPS_ERR);
 657
 658                 drain_resp_pkts(qp);
 659                 flush_send_queue(qp, notify);
 660                 spin_unlock_irqrestore(&qp->state_lock, flags);
 661                 goto exit;
 662         }
 663         spin_unlock_irqrestore(&qp->state_lock, flags);
 664
 665         if (qp->comp.timeout) {
 666                 qp->comp.timeout_retry = 1;
 667                 qp->comp.timeout = 0;
 668         } else {
 669                 qp->comp.timeout_retry = 0;
 670         }
 671
 672         if (qp->req.need_retry)
 673                 goto exit;
 674
 675         state = COMPST_GET_ACK;
 676
 677         while (1) {
 678                 rxe_dbg_qp(qp, "state = %s\n", comp_state_name[state]);
 679                 switch (state) {
 680                 case COMPST_GET_ACK:
 681                         skb = skb_dequeue(&qp->resp_pkts);
 682                         if (skb) {
 683                                 pkt = SKB_TO_PKT(skb);
 684                                 qp->comp.timeout_retry = 0;
 685                         }
 686                         state = COMPST_GET_WQE;
 687                         break;
 688
 689                 case COMPST_GET_WQE:
 690                         state = get_wqe(qp, pkt, &wqe);
 691                         break;
 692
 693                 case COMPST_CHECK_PSN:
 694                         state = check_psn(qp, pkt, wqe);
 695                         break;
 696
 697                 case COMPST_CHECK_ACK:
 698                         state = check_ack(qp, pkt, wqe);
 699                         break;
 700
 701                 case COMPST_READ:
 702                         state = do_read(qp, pkt, wqe);
 703                         break;
 704
 705                 case COMPST_ATOMIC:
 706                         state = do_atomic(qp, pkt, wqe);
 707                         break;
 708
 709                 case COMPST_WRITE_SEND:
 710                         if (wqe->state == wqe_state_pending &&
 711                             wqe->last_psn == pkt->psn)
 712                                 state = COMPST_COMP_ACK;
 713                         else
 714                                 state = COMPST_UPDATE_COMP;
 715                         break;
 716
 717                 case COMPST_COMP_ACK:
 718                         state = complete_ack(qp, pkt, wqe);
 719                         break;
 720
 721                 case COMPST_COMP_WQE:
 722                         state = complete_wqe(qp, pkt, wqe);
 723                         break;
 724
 725                 case COMPST_UPDATE_COMP:
 726                         if (pkt->mask & RXE_END_MASK)
 727                                 qp->comp.opcode = -1;
 728                         else
 729                                 qp->comp.opcode = pkt->opcode;
 730
 731                         if (psn_compare(pkt->psn, qp->comp.psn) >= 0)
 732                                 qp->comp.psn = (pkt->psn + 1) & BTH_PSN_MASK;
 733
 734                         if (qp->req.wait_psn) {
 735                                 qp->req.wait_psn = 0;
 736                                 rxe_sched_task(&qp->req.task);
 737                         }
 738
 739                         state = COMPST_DONE;
 740                         break;
 741
 742                 case COMPST_DONE:
 743                         goto done;
 744
 745                 case COMPST_EXIT:
 746                         if (qp->comp.timeout_retry && wqe) {
 747                                 state = COMPST_ERROR_RETRY;
 748                                 break;
 749                         }
 750
 751                         reset_retry_timer(qp);
 752                         goto exit;
 753
 754                 case COMPST_ERROR_RETRY:
 755                         /* we come here if the retry timer fired and we did
 756                          * not receive a response packet. try to retry the send
 757                          * queue if that makes sense and the limits have not
 758                          * been exceeded. remember that some timeouts are
 759                          * spurious since we do not reset the timer but kick
 760                          * it down the road or let it expire
 761                          */
 762
 763                         /* there is nothing to retry in this case */
 764                         if (!wqe || (wqe->state == wqe_state_posted))
 765                                 goto exit;
 766
 767                         /* if we've started a retry, don't start another
 768                          * retry sequence, unless this is a timeout.
 769                          */
 770                         if (qp->comp.started_retry &&
 771                             !qp->comp.timeout_retry)
 772                                 goto done;
 773
 774                         if (qp->comp.retry_cnt > 0) {
 775                                 if (qp->comp.retry_cnt != 7)
 776                                         qp->comp.retry_cnt--;
 777
 778                                 /* no point in retrying if we have already
 779                                  * seen the last ack that the requester could
 780                                  * have caused
 781                                  */
 782                                 if (psn_compare(qp->req.psn,
 783                                                 qp->comp.psn) > 0) {
 784                                         /* tell the requester to retry the
 785                                          * send queue next time around
 786                                          */
 787                                         rxe_counter_inc(rxe,
 788                                                         RXE_CNT_COMP_RETRY);
 789                                         qp->req.need_retry = 1;
 790                                         qp->comp.started_retry = 1;
 791                                         rxe_sched_task(&qp->req.task);
 792                                 }
 793                                 goto done;
 794
 795                         } else {
 796                                 rxe_counter_inc(rxe, RXE_CNT_RETRY_EXCEEDED);
 797                                 wqe->status = IB_WC_RETRY_EXC_ERR;
 798                                 state = COMPST_ERROR;
 799                         }
 800                         break;
 801
 802                 case COMPST_RNR_RETRY:
 803                         /* we come here if we received an RNR NAK */
 804                         if (qp->comp.rnr_retry > 0) {
 805                                 if (qp->comp.rnr_retry != 7)
 806                                         qp->comp.rnr_retry--;
 807
 808                                 /* don't start a retry flow until the
 809                                  * rnr timer has fired
 810                                  */
 811                                 qp->req.wait_for_rnr_timer = 1;
 812                                 rxe_dbg_qp(qp, "set rnr nak timer\n");
 813                                 // TODO who protects from destroy_qp??
 814                                 mod_timer(&qp->rnr_nak_timer,
 815                                           jiffies + rnrnak_jiffies(aeth_syn(pkt)
 816                                                 & ~AETH_TYPE_MASK));
 817                                 goto exit;
 818                         } else {
 819                                 rxe_counter_inc(rxe,
 820                                                 RXE_CNT_RNR_RETRY_EXCEEDED);
 821                                 wqe->status = IB_WC_RNR_RETRY_EXC_ERR;
 822                                 state = COMPST_ERROR;
 823                         }
 824                         break;
 825
 826                 case COMPST_ERROR:
 827                         WARN_ON_ONCE(wqe->status == IB_WC_SUCCESS);
 828                         do_complete(qp, wqe);
 829                         rxe_qp_error(qp);
 830                         goto exit;
 831                 }
 832         }
 833
 834         /* A non-zero return value will cause rxe_do_task to
 835          * exit its loop and end the tasklet. A zero return
 836          * will continue looping and return to rxe_completer
 837          */
 838 done:
 839         ret = 0;
 840         goto out;
 841 exit:
 842         ret = -EAGAIN;
 843 out:
 844         if (pkt)
 845                 free_pkt(pkt);
 846         return ret;
 847 }