drivers/infiniband/sw/rxe/rxe_comp.c

   1 /*
   2  * Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
   3  * Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
   4  *
   5  * This software is available to you under a choice of one of two
   6  * licenses.  You may choose to be licensed under the terms of the GNU
   7  * General Public License (GPL) Version 2, available from the file
   8  * COPYING in the main directory of this source tree, or the
   9  * OpenIB.org BSD license below:
  10  *
  11  *     Redistribution and use in source and binary forms, with or
  12  *     without modification, are permitted provided that the following
  13  *     conditions are met:
  14  *
  15  *      - Redistributions of source code must retain the above
  16  *        copyright notice, this list of conditions and the following
  17  *        disclaimer.
  18  *
  19  *      - Redistributions in binary form must reproduce the above
  20  *        copyright notice, this list of conditions and the following
  21  *        disclaimer in the documentation and/or other materials
  22  *        provided with the distribution.
  23  *
  24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  25  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  26  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  27  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  28  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  29  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  30  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  31  * SOFTWARE.
  32  */
  33
  34 #include <linux/skbuff.h>
  35
  36 #include "rxe.h"
  37 #include "rxe_loc.h"
  38 #include "rxe_queue.h"
  39 #include "rxe_task.h"
  40
  41 enum comp_state {
  42         COMPST_GET_ACK,
  43         COMPST_GET_WQE,
  44         COMPST_COMP_WQE,
  45         COMPST_COMP_ACK,
  46         COMPST_CHECK_PSN,
  47         COMPST_CHECK_ACK,
  48         COMPST_READ,
  49         COMPST_ATOMIC,
  50         COMPST_WRITE_SEND,
  51         COMPST_UPDATE_COMP,
  52         COMPST_ERROR_RETRY,
  53         COMPST_RNR_RETRY,
  54         COMPST_ERROR,
  55         COMPST_EXIT, /* We have an issue, and we want to rerun the completer */
  56         COMPST_DONE, /* The completer finished successflly */
  57 };
  58
  59 static char *comp_state_name[] =  {
  60         [COMPST_GET_ACK]                = "GET ACK",
  61         [COMPST_GET_WQE]                = "GET WQE",
  62         [COMPST_COMP_WQE]               = "COMP WQE",
  63         [COMPST_COMP_ACK]               = "COMP ACK",
  64         [COMPST_CHECK_PSN]              = "CHECK PSN",
  65         [COMPST_CHECK_ACK]              = "CHECK ACK",
  66         [COMPST_READ]                   = "READ",
  67         [COMPST_ATOMIC]                 = "ATOMIC",
  68         [COMPST_WRITE_SEND]             = "WRITE/SEND",
  69         [COMPST_UPDATE_COMP]            = "UPDATE COMP",
  70         [COMPST_ERROR_RETRY]            = "ERROR RETRY",
  71         [COMPST_RNR_RETRY]              = "RNR RETRY",
  72         [COMPST_ERROR]                  = "ERROR",
  73         [COMPST_EXIT]                   = "EXIT",
  74         [COMPST_DONE]                   = "DONE",
  75 };
  76
  77 static unsigned long rnrnak_usec[32] = {
  78         [IB_RNR_TIMER_655_36] = 655360,
  79         [IB_RNR_TIMER_000_01] = 10,
  80         [IB_RNR_TIMER_000_02] = 20,
  81         [IB_RNR_TIMER_000_03] = 30,
  82         [IB_RNR_TIMER_000_04] = 40,
  83         [IB_RNR_TIMER_000_06] = 60,
  84         [IB_RNR_TIMER_000_08] = 80,
  85         [IB_RNR_TIMER_000_12] = 120,
  86         [IB_RNR_TIMER_000_16] = 160,
  87         [IB_RNR_TIMER_000_24] = 240,
  88         [IB_RNR_TIMER_000_32] = 320,
  89         [IB_RNR_TIMER_000_48] = 480,
  90         [IB_RNR_TIMER_000_64] = 640,
  91         [IB_RNR_TIMER_000_96] = 960,
  92         [IB_RNR_TIMER_001_28] = 1280,
  93         [IB_RNR_TIMER_001_92] = 1920,
  94         [IB_RNR_TIMER_002_56] = 2560,
  95         [IB_RNR_TIMER_003_84] = 3840,
  96         [IB_RNR_TIMER_005_12] = 5120,
  97         [IB_RNR_TIMER_007_68] = 7680,
  98         [IB_RNR_TIMER_010_24] = 10240,
  99         [IB_RNR_TIMER_015_36] = 15360,
 100         [IB_RNR_TIMER_020_48] = 20480,
 101         [IB_RNR_TIMER_030_72] = 30720,
 102         [IB_RNR_TIMER_040_96] = 40960,
 103         [IB_RNR_TIMER_061_44] = 61410,
 104         [IB_RNR_TIMER_081_92] = 81920,
 105         [IB_RNR_TIMER_122_88] = 122880,
 106         [IB_RNR_TIMER_163_84] = 163840,
 107         [IB_RNR_TIMER_245_76] = 245760,
 108         [IB_RNR_TIMER_327_68] = 327680,
 109         [IB_RNR_TIMER_491_52] = 491520,
 110 };
 111
 112 static inline unsigned long rnrnak_jiffies(u8 timeout)
 113 {
 114         return max_t(unsigned long,
 115                 usecs_to_jiffies(rnrnak_usec[timeout]), 1);
 116 }
 117
 118 static enum ib_wc_opcode wr_to_wc_opcode(enum ib_wr_opcode opcode)
 119 {
 120         switch (opcode) {
 121         case IB_WR_RDMA_WRITE:                  return IB_WC_RDMA_WRITE;
 122         case IB_WR_RDMA_WRITE_WITH_IMM:         return IB_WC_RDMA_WRITE;
 123         case IB_WR_SEND:                        return IB_WC_SEND;
 124         case IB_WR_SEND_WITH_IMM:               return IB_WC_SEND;
 125         case IB_WR_RDMA_READ:                   return IB_WC_RDMA_READ;
 126         case IB_WR_ATOMIC_CMP_AND_SWP:          return IB_WC_COMP_SWAP;
 127         case IB_WR_ATOMIC_FETCH_AND_ADD:        return IB_WC_FETCH_ADD;
 128         case IB_WR_LSO:                         return IB_WC_LSO;
 129         case IB_WR_SEND_WITH_INV:               return IB_WC_SEND;
 130         case IB_WR_RDMA_READ_WITH_INV:          return IB_WC_RDMA_READ;
 131         case IB_WR_LOCAL_INV:                   return IB_WC_LOCAL_INV;
 132         case IB_WR_REG_MR:                      return IB_WC_REG_MR;
 133
 134         default:
 135                 return 0xff;
 136         }
 137 }
 138
 139 void retransmit_timer(struct timer_list *t)
 140 {
 141         struct rxe_qp *qp = from_timer(qp, t, retrans_timer);
 142
 143         if (qp->valid) {
 144                 qp->comp.timeout = 1;
 145                 rxe_run_task(&qp->comp.task, 1);
 146         }
 147 }
 148
 149 void rxe_comp_queue_pkt(struct rxe_dev *rxe, struct rxe_qp *qp,
 150                         struct sk_buff *skb)
 151 {
 152         int must_sched;
 153
 154         skb_queue_tail(&qp->resp_pkts, skb);
 155
 156         must_sched = skb_queue_len(&qp->resp_pkts) > 1;
 157         if (must_sched != 0)
 158                 rxe_counter_inc(rxe, RXE_CNT_COMPLETER_SCHED);
 159         rxe_run_task(&qp->comp.task, must_sched);
 160 }
 161
 162 static inline enum comp_state get_wqe(struct rxe_qp *qp,
 163                                       struct rxe_pkt_info *pkt,
 164                                       struct rxe_send_wqe **wqe_p)
 165 {
 166         struct rxe_send_wqe *wqe;
 167
 168         /* we come here whether or not we found a response packet to see if
 169          * there are any posted WQEs
 170          */
 171         wqe = queue_head(qp->sq.queue);
 172         *wqe_p = wqe;
 173
 174         /* no WQE or requester has not started it yet */
 175         if (!wqe || wqe->state == wqe_state_posted)
 176                 return pkt ? COMPST_DONE : COMPST_EXIT;
 177
 178         /* WQE does not require an ack */
 179         if (wqe->state == wqe_state_done)
 180                 return COMPST_COMP_WQE;
 181
 182         /* WQE caused an error */
 183         if (wqe->state == wqe_state_error)
 184                 return COMPST_ERROR;
 185
 186         /* we have a WQE, if we also have an ack check its PSN */
 187         return pkt ? COMPST_CHECK_PSN : COMPST_EXIT;
 188 }
 189
 190 static inline void reset_retry_counters(struct rxe_qp *qp)
 191 {
 192         qp->comp.retry_cnt = qp->attr.retry_cnt;
 193         qp->comp.rnr_retry = qp->attr.rnr_retry;
 194         qp->comp.started_retry = 0;
 195 }
 196
 197 static inline enum comp_state check_psn(struct rxe_qp *qp,
 198                                         struct rxe_pkt_info *pkt,
 199                                         struct rxe_send_wqe *wqe)
 200 {
 201         s32 diff;
 202
 203         /* check to see if response is past the oldest WQE. if it is, complete
 204          * send/write or error read/atomic
 205          */
 206         diff = psn_compare(pkt->psn, wqe->last_psn);
 207         if (diff > 0) {
 208                 if (wqe->state == wqe_state_pending) {
 209                         if (wqe->mask & WR_ATOMIC_OR_READ_MASK)
 210                                 return COMPST_ERROR_RETRY;
 211
 212                         reset_retry_counters(qp);
 213                         return COMPST_COMP_WQE;
 214                 } else {
 215                         return COMPST_DONE;
 216                 }
 217         }
 218
 219         /* compare response packet to expected response */
 220         diff = psn_compare(pkt->psn, qp->comp.psn);
 221         if (diff < 0) {
 222                 /* response is most likely a retried packet if it matches an
 223                  * uncompleted WQE go complete it else ignore it
 224                  */
 225                 if (pkt->psn == wqe->last_psn)
 226                         return COMPST_COMP_ACK;
 227                 else
 228                         return COMPST_DONE;
 229         } else if ((diff > 0) && (wqe->mask & WR_ATOMIC_OR_READ_MASK)) {
 230                 return COMPST_DONE;
 231         } else {
 232                 return COMPST_CHECK_ACK;
 233         }
 234 }
 235
 236 static inline enum comp_state check_ack(struct rxe_qp *qp,
 237                                         struct rxe_pkt_info *pkt,
 238                                         struct rxe_send_wqe *wqe)
 239 {
 240         unsigned int mask = pkt->mask;
 241         u8 syn;
 242         struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
 243
 244         /* Check the sequence only */
 245         switch (qp->comp.opcode) {
 246         case -1:
 247                 /* Will catch all *_ONLY cases. */
 248                 if (!(mask & RXE_START_MASK))
 249                         return COMPST_ERROR;
 250
 251                 break;
 252
 253         case IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST:
 254         case IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE:
 255                 if (pkt->opcode != IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE &&
 256                     pkt->opcode != IB_OPCODE_RC_RDMA_READ_RESPONSE_LAST) {
 257                         /* read retries of partial data may restart from
 258                          * read response first or response only.
 259                          */
 260                         if ((pkt->psn == wqe->first_psn &&
 261                              pkt->opcode ==
 262                              IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST) ||
 263                             (wqe->first_psn == wqe->last_psn &&
 264                              pkt->opcode ==
 265                              IB_OPCODE_RC_RDMA_READ_RESPONSE_ONLY))
 266                                 break;
 267
 268                         return COMPST_ERROR;
 269                 }
 270                 break;
 271         default:
 272                 WARN_ON_ONCE(1);
 273         }
 274
 275         /* Check operation validity. */
 276         switch (pkt->opcode) {
 277         case IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST:
 278         case IB_OPCODE_RC_RDMA_READ_RESPONSE_LAST:
 279         case IB_OPCODE_RC_RDMA_READ_RESPONSE_ONLY:
 280                 syn = aeth_syn(pkt);
 281
 282                 if ((syn & AETH_TYPE_MASK) != AETH_ACK)
 283                         return COMPST_ERROR;
 284
 285                 /* fall through */
 286                 /* (IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE doesn't have an AETH)
 287                  */
 288         case IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE:
 289                 if (wqe->wr.opcode != IB_WR_RDMA_READ &&
 290                     wqe->wr.opcode != IB_WR_RDMA_READ_WITH_INV) {
 291                         wqe->status = IB_WC_FATAL_ERR;
 292                         return COMPST_ERROR;
 293                 }
 294                 reset_retry_counters(qp);
 295                 return COMPST_READ;
 296
 297         case IB_OPCODE_RC_ATOMIC_ACKNOWLEDGE:
 298                 syn = aeth_syn(pkt);
 299
 300                 if ((syn & AETH_TYPE_MASK) != AETH_ACK)
 301                         return COMPST_ERROR;
 302
 303                 if (wqe->wr.opcode != IB_WR_ATOMIC_CMP_AND_SWP &&
 304                     wqe->wr.opcode != IB_WR_ATOMIC_FETCH_AND_ADD)
 305                         return COMPST_ERROR;
 306                 reset_retry_counters(qp);
 307                 return COMPST_ATOMIC;
 308
 309         case IB_OPCODE_RC_ACKNOWLEDGE:
 310                 syn = aeth_syn(pkt);
 311                 switch (syn & AETH_TYPE_MASK) {
 312                 case AETH_ACK:
 313                         reset_retry_counters(qp);
 314                         return COMPST_WRITE_SEND;
 315
 316                 case AETH_RNR_NAK:
 317                         rxe_counter_inc(rxe, RXE_CNT_RCV_RNR);
 318                         return COMPST_RNR_RETRY;
 319
 320                 case AETH_NAK:
 321                         switch (syn) {
 322                         case AETH_NAK_PSN_SEQ_ERROR:
 323                                 /* a nak implicitly acks all packets with psns
 324                                  * before
 325                                  */
 326                                 if (psn_compare(pkt->psn, qp->comp.psn) > 0) {
 327                                         rxe_counter_inc(rxe,
 328                                                         RXE_CNT_RCV_SEQ_ERR);
 329                                         qp->comp.psn = pkt->psn;
 330                                         if (qp->req.wait_psn) {
 331                                                 qp->req.wait_psn = 0;
 332                                                 rxe_run_task(&qp->req.task, 0);
 333                                         }
 334                                 }
 335                                 return COMPST_ERROR_RETRY;
 336
 337                         case AETH_NAK_INVALID_REQ:
 338                                 wqe->status = IB_WC_REM_INV_REQ_ERR;
 339                                 return COMPST_ERROR;
 340
 341                         case AETH_NAK_REM_ACC_ERR:
 342                                 wqe->status = IB_WC_REM_ACCESS_ERR;
 343                                 return COMPST_ERROR;
 344
 345                         case AETH_NAK_REM_OP_ERR:
 346                                 wqe->status = IB_WC_REM_OP_ERR;
 347                                 return COMPST_ERROR;
 348
 349                         default:
 350                                 pr_warn("unexpected nak %x\n", syn);
 351                                 wqe->status = IB_WC_REM_OP_ERR;
 352                                 return COMPST_ERROR;
 353                         }
 354
 355                 default:
 356                         return COMPST_ERROR;
 357                 }
 358                 break;
 359
 360         default:
 361                 pr_warn("unexpected opcode\n");
 362         }
 363
 364         return COMPST_ERROR;
 365 }
 366
 367 static inline enum comp_state do_read(struct rxe_qp *qp,
 368                                       struct rxe_pkt_info *pkt,
 369                                       struct rxe_send_wqe *wqe)
 370 {
 371         int ret;
 372
 373         ret = copy_data(qp->pd, IB_ACCESS_LOCAL_WRITE,
 374                         &wqe->dma, payload_addr(pkt),
 375                         payload_size(pkt), to_mem_obj, NULL);
 376         if (ret)
 377                 return COMPST_ERROR;
 378
 379         if (wqe->dma.resid == 0 && (pkt->mask & RXE_END_MASK))
 380                 return COMPST_COMP_ACK;
 381         else
 382                 return COMPST_UPDATE_COMP;
 383 }
 384
 385 static inline enum comp_state do_atomic(struct rxe_qp *qp,
 386                                         struct rxe_pkt_info *pkt,
 387                                         struct rxe_send_wqe *wqe)
 388 {
 389         int ret;
 390
 391         u64 atomic_orig = atmack_orig(pkt);
 392
 393         ret = copy_data(qp->pd, IB_ACCESS_LOCAL_WRITE,
 394                         &wqe->dma, &atomic_orig,
 395                         sizeof(u64), to_mem_obj, NULL);
 396         if (ret)
 397                 return COMPST_ERROR;
 398         else
 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         memset(cqe, 0, sizeof(*cqe));
 406
 407         if (!qp->is_user) {
 408                 struct ib_wc            *wc     = &cqe->ibwc;
 409
 410                 wc->wr_id               = wqe->wr.wr_id;
 411                 wc->status              = wqe->status;
 412                 wc->opcode              = wr_to_wc_opcode(wqe->wr.opcode);
 413                 if (wqe->wr.opcode == IB_WR_RDMA_WRITE_WITH_IMM ||
 414                     wqe->wr.opcode == IB_WR_SEND_WITH_IMM)
 415                         wc->wc_flags = IB_WC_WITH_IMM;
 416                 wc->byte_len            = wqe->dma.length;
 417                 wc->qp                  = &qp->ibqp;
 418         } else {
 419                 struct ib_uverbs_wc     *uwc    = &cqe->uibwc;
 420
 421                 uwc->wr_id              = wqe->wr.wr_id;
 422                 uwc->status             = wqe->status;
 423                 uwc->opcode             = wr_to_wc_opcode(wqe->wr.opcode);
 424                 if (wqe->wr.opcode == IB_WR_RDMA_WRITE_WITH_IMM ||
 425                     wqe->wr.opcode == IB_WR_SEND_WITH_IMM)
 426                         uwc->wc_flags = IB_WC_WITH_IMM;
 427                 uwc->byte_len           = wqe->dma.length;
 428                 uwc->qp_num             = qp->ibqp.qp_num;
 429         }
 430 }
 431
 432 /*
 433  * IBA Spec. Section 10.7.3.1 SIGNALED COMPLETIONS
 434  * ---------8<---------8<-------------
 435  * ...Note that if a completion error occurs, a Work Completion
 436  * will always be generated, even if the signaling
 437  * indicator requests an Unsignaled Completion.
 438  * ---------8<---------8<-------------
 439  */
 440 static void do_complete(struct rxe_qp *qp, struct rxe_send_wqe *wqe)
 441 {
 442         struct rxe_cqe cqe;
 443
 444         if ((qp->sq_sig_type == IB_SIGNAL_ALL_WR) ||
 445             (wqe->wr.send_flags & IB_SEND_SIGNALED) ||
 446             wqe->status != IB_WC_SUCCESS) {
 447                 make_send_cqe(qp, wqe, &cqe);
 448                 advance_consumer(qp->sq.queue);
 449                 rxe_cq_post(qp->scq, &cqe, 0);
 450         } else {
 451                 advance_consumer(qp->sq.queue);
 452         }
 453
 454         /*
 455          * we completed something so let req run again
 456          * if it is trying to fence
 457          */
 458         if (qp->req.wait_fence) {
 459                 qp->req.wait_fence = 0;
 460                 rxe_run_task(&qp->req.task, 0);
 461         }
 462 }
 463
 464 static inline enum comp_state complete_ack(struct rxe_qp *qp,
 465                                            struct rxe_pkt_info *pkt,
 466                                            struct rxe_send_wqe *wqe)
 467 {
 468         unsigned long flags;
 469
 470         if (wqe->has_rd_atomic) {
 471                 wqe->has_rd_atomic = 0;
 472                 atomic_inc(&qp->req.rd_atomic);
 473                 if (qp->req.need_rd_atomic) {
 474                         qp->comp.timeout_retry = 0;
 475                         qp->req.need_rd_atomic = 0;
 476                         rxe_run_task(&qp->req.task, 0);
 477                 }
 478         }
 479
 480         if (unlikely(qp->req.state == QP_STATE_DRAIN)) {
 481                 /* state_lock used by requester & completer */
 482                 spin_lock_irqsave(&qp->state_lock, flags);
 483                 if ((qp->req.state == QP_STATE_DRAIN) &&
 484                     (qp->comp.psn == qp->req.psn)) {
 485                         qp->req.state = QP_STATE_DRAINED;
 486                         spin_unlock_irqrestore(&qp->state_lock, flags);
 487
 488                         if (qp->ibqp.event_handler) {
 489                                 struct ib_event ev;
 490
 491                                 ev.device = qp->ibqp.device;
 492                                 ev.element.qp = &qp->ibqp;
 493                                 ev.event = IB_EVENT_SQ_DRAINED;
 494                                 qp->ibqp.event_handler(&ev,
 495                                         qp->ibqp.qp_context);
 496                         }
 497                 } else {
 498                         spin_unlock_irqrestore(&qp->state_lock, flags);
 499                 }
 500         }
 501
 502         do_complete(qp, wqe);
 503
 504         if (psn_compare(pkt->psn, qp->comp.psn) >= 0)
 505                 return COMPST_UPDATE_COMP;
 506         else
 507                 return COMPST_DONE;
 508 }
 509
 510 static inline enum comp_state complete_wqe(struct rxe_qp *qp,
 511                                            struct rxe_pkt_info *pkt,
 512                                            struct rxe_send_wqe *wqe)
 513 {
 514         if (pkt && wqe->state == wqe_state_pending) {
 515                 if (psn_compare(wqe->last_psn, qp->comp.psn) >= 0) {
 516                         qp->comp.psn = (wqe->last_psn + 1) & BTH_PSN_MASK;
 517                         qp->comp.opcode = -1;
 518                 }
 519
 520                 if (qp->req.wait_psn) {
 521                         qp->req.wait_psn = 0;
 522                         rxe_run_task(&qp->req.task, 1);
 523                 }
 524         }
 525
 526         do_complete(qp, wqe);
 527
 528         return COMPST_GET_WQE;
 529 }
 530
 531 static void rxe_drain_resp_pkts(struct rxe_qp *qp, bool notify)
 532 {
 533         struct sk_buff *skb;
 534         struct rxe_send_wqe *wqe;
 535
 536         while ((skb = skb_dequeue(&qp->resp_pkts))) {
 537                 rxe_drop_ref(qp);
 538                 kfree_skb(skb);
 539         }
 540
 541         while ((wqe = queue_head(qp->sq.queue))) {
 542                 if (notify) {
 543                         wqe->status = IB_WC_WR_FLUSH_ERR;
 544                         do_complete(qp, wqe);
 545                 } else {
 546                         advance_consumer(qp->sq.queue);
 547                 }
 548         }
 549 }
 550
 551 int rxe_completer(void *arg)
 552 {
 553         struct rxe_qp *qp = (struct rxe_qp *)arg;
 554         struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
 555         struct rxe_send_wqe *wqe = wqe;
 556         struct sk_buff *skb = NULL;
 557         struct rxe_pkt_info *pkt = NULL;
 558         enum comp_state state;
 559
 560         rxe_add_ref(qp);
 561
 562         if (!qp->valid || qp->req.state == QP_STATE_ERROR ||
 563             qp->req.state == QP_STATE_RESET) {
 564                 rxe_drain_resp_pkts(qp, qp->valid &&
 565                                     qp->req.state == QP_STATE_ERROR);
 566                 goto exit;
 567         }
 568
 569         if (qp->comp.timeout) {
 570                 qp->comp.timeout_retry = 1;
 571                 qp->comp.timeout = 0;
 572         } else {
 573                 qp->comp.timeout_retry = 0;
 574         }
 575
 576         if (qp->req.need_retry)
 577                 goto exit;
 578
 579         state = COMPST_GET_ACK;
 580
 581         while (1) {
 582                 pr_debug("qp#%d state = %s\n", qp_num(qp),
 583                          comp_state_name[state]);
 584                 switch (state) {
 585                 case COMPST_GET_ACK:
 586                         skb = skb_dequeue(&qp->resp_pkts);
 587                         if (skb) {
 588                                 pkt = SKB_TO_PKT(skb);
 589                                 qp->comp.timeout_retry = 0;
 590                         }
 591                         state = COMPST_GET_WQE;
 592                         break;
 593
 594                 case COMPST_GET_WQE:
 595                         state = get_wqe(qp, pkt, &wqe);
 596                         break;
 597
 598                 case COMPST_CHECK_PSN:
 599                         state = check_psn(qp, pkt, wqe);
 600                         break;
 601
 602                 case COMPST_CHECK_ACK:
 603                         state = check_ack(qp, pkt, wqe);
 604                         break;
 605
 606                 case COMPST_READ:
 607                         state = do_read(qp, pkt, wqe);
 608                         break;
 609
 610                 case COMPST_ATOMIC:
 611                         state = do_atomic(qp, pkt, wqe);
 612                         break;
 613
 614                 case COMPST_WRITE_SEND:
 615                         if (wqe->state == wqe_state_pending &&
 616                             wqe->last_psn == pkt->psn)
 617                                 state = COMPST_COMP_ACK;
 618                         else
 619                                 state = COMPST_UPDATE_COMP;
 620                         break;
 621
 622                 case COMPST_COMP_ACK:
 623                         state = complete_ack(qp, pkt, wqe);
 624                         break;
 625
 626                 case COMPST_COMP_WQE:
 627                         state = complete_wqe(qp, pkt, wqe);
 628                         break;
 629
 630                 case COMPST_UPDATE_COMP:
 631                         if (pkt->mask & RXE_END_MASK)
 632                                 qp->comp.opcode = -1;
 633                         else
 634                                 qp->comp.opcode = pkt->opcode;
 635
 636                         if (psn_compare(pkt->psn, qp->comp.psn) >= 0)
 637                                 qp->comp.psn = (pkt->psn + 1) & BTH_PSN_MASK;
 638
 639                         if (qp->req.wait_psn) {
 640                                 qp->req.wait_psn = 0;
 641                                 rxe_run_task(&qp->req.task, 1);
 642                         }
 643
 644                         state = COMPST_DONE;
 645                         break;
 646
 647                 case COMPST_DONE:
 648                         if (pkt) {
 649                                 rxe_drop_ref(pkt->qp);
 650                                 kfree_skb(skb);
 651                                 skb = NULL;
 652                         }
 653                         goto done;
 654
 655                 case COMPST_EXIT:
 656                         if (qp->comp.timeout_retry && wqe) {
 657                                 state = COMPST_ERROR_RETRY;
 658                                 break;
 659                         }
 660
 661                         /* re reset the timeout counter if
 662                          * (1) QP is type RC
 663                          * (2) the QP is alive
 664                          * (3) there is a packet sent by the requester that
 665                          *     might be acked (we still might get spurious
 666                          *     timeouts but try to keep them as few as possible)
 667                          * (4) the timeout parameter is set
 668                          */
 669                         if ((qp_type(qp) == IB_QPT_RC) &&
 670                             (qp->req.state == QP_STATE_READY) &&
 671                             (psn_compare(qp->req.psn, qp->comp.psn) > 0) &&
 672                             qp->qp_timeout_jiffies)
 673                                 mod_timer(&qp->retrans_timer,
 674                                           jiffies + qp->qp_timeout_jiffies);
 675                         goto exit;
 676
 677                 case COMPST_ERROR_RETRY:
 678                         /* we come here if the retry timer fired and we did
 679                          * not receive a response packet. try to retry the send
 680                          * queue if that makes sense and the limits have not
 681                          * been exceeded. remember that some timeouts are
 682                          * spurious since we do not reset the timer but kick
 683                          * it down the road or let it expire
 684                          */
 685
 686                         /* there is nothing to retry in this case */
 687                         if (!wqe || (wqe->state == wqe_state_posted)) {
 688                                 goto exit;
 689                         }
 690
 691                         /* if we've started a retry, don't start another
 692                          * retry sequence, unless this is a timeout.
 693                          */
 694                         if (qp->comp.started_retry &&
 695                             !qp->comp.timeout_retry) {
 696                                 if (pkt) {
 697                                         rxe_drop_ref(pkt->qp);
 698                                         kfree_skb(skb);
 699                                         skb = NULL;
 700                                 }
 701
 702                                 goto done;
 703                         }
 704
 705                         if (qp->comp.retry_cnt > 0) {
 706                                 if (qp->comp.retry_cnt != 7)
 707                                         qp->comp.retry_cnt--;
 708
 709                                 /* no point in retrying if we have already
 710                                  * seen the last ack that the requester could
 711                                  * have caused
 712                                  */
 713                                 if (psn_compare(qp->req.psn,
 714                                                 qp->comp.psn) > 0) {
 715                                         /* tell the requester to retry the
 716                                          * send queue next time around
 717                                          */
 718                                         rxe_counter_inc(rxe,
 719                                                         RXE_CNT_COMP_RETRY);
 720                                         qp->req.need_retry = 1;
 721                                         qp->comp.started_retry = 1;
 722                                         rxe_run_task(&qp->req.task, 0);
 723                                 }
 724
 725                                 if (pkt) {
 726                                         rxe_drop_ref(pkt->qp);
 727                                         kfree_skb(skb);
 728                                         skb = NULL;
 729                                 }
 730
 731                                 goto done;
 732
 733                         } else {
 734                                 rxe_counter_inc(rxe, RXE_CNT_RETRY_EXCEEDED);
 735                                 wqe->status = IB_WC_RETRY_EXC_ERR;
 736                                 state = COMPST_ERROR;
 737                         }
 738                         break;
 739
 740                 case COMPST_RNR_RETRY:
 741                         if (qp->comp.rnr_retry > 0) {
 742                                 if (qp->comp.rnr_retry != 7)
 743                                         qp->comp.rnr_retry--;
 744
 745                                 qp->req.need_retry = 1;
 746                                 pr_debug("qp#%d set rnr nak timer\n",
 747                                          qp_num(qp));
 748                                 mod_timer(&qp->rnr_nak_timer,
 749                                           jiffies + rnrnak_jiffies(aeth_syn(pkt)
 750                                                 & ~AETH_TYPE_MASK));
 751                                 rxe_drop_ref(pkt->qp);
 752                                 kfree_skb(skb);
 753                                 skb = NULL;
 754                                 goto exit;
 755                         } else {
 756                                 rxe_counter_inc(rxe,
 757                                                 RXE_CNT_RNR_RETRY_EXCEEDED);
 758                                 wqe->status = IB_WC_RNR_RETRY_EXC_ERR;
 759                                 state = COMPST_ERROR;
 760                         }
 761                         break;
 762
 763                 case COMPST_ERROR:
 764                         WARN_ON_ONCE(wqe->status == IB_WC_SUCCESS);
 765                         do_complete(qp, wqe);
 766                         rxe_qp_error(qp);
 767
 768                         if (pkt) {
 769                                 rxe_drop_ref(pkt->qp);
 770                                 kfree_skb(skb);
 771                                 skb = NULL;
 772                         }
 773
 774                         goto exit;
 775                 }
 776         }
 777
 778 exit:
 779         /* we come here if we are done with processing and want the task to
 780          * exit from the loop calling us
 781          */
 782         WARN_ON_ONCE(skb);
 783         rxe_drop_ref(qp);
 784         return -EAGAIN;
 785
 786 done:
 787         /* we come here if we have processed a packet we want the task to call
 788          * us again to see if there is anything else to do
 789          */
 790         WARN_ON_ONCE(skb);
 791         rxe_drop_ref(qp);
 792         return 0;
 793 }