linux/drivers/infiniband/sw/rxe/rxe_comp.c
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   1// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
   2/*
   3 * Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
   4 * Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
   5 */
   6
   7#include <linux/skbuff.h>
   8
   9#include "rxe.h"
  10#include "rxe_loc.h"
  11#include "rxe_queue.h"
  12#include "rxe_task.h"
  13
  14enum comp_state {
  15        COMPST_GET_ACK,
  16        COMPST_GET_WQE,
  17        COMPST_COMP_WQE,
  18        COMPST_COMP_ACK,
  19        COMPST_CHECK_PSN,
  20        COMPST_CHECK_ACK,
  21        COMPST_READ,
  22        COMPST_ATOMIC,
  23        COMPST_WRITE_SEND,
  24        COMPST_UPDATE_COMP,
  25        COMPST_ERROR_RETRY,
  26        COMPST_RNR_RETRY,
  27        COMPST_ERROR,
  28        COMPST_EXIT, /* We have an issue, and we want to rerun the completer */
  29        COMPST_DONE, /* The completer finished successflly */
  30};
  31
  32static char *comp_state_name[] =  {
  33        [COMPST_GET_ACK]                = "GET ACK",
  34        [COMPST_GET_WQE]                = "GET WQE",
  35        [COMPST_COMP_WQE]               = "COMP WQE",
  36        [COMPST_COMP_ACK]               = "COMP ACK",
  37        [COMPST_CHECK_PSN]              = "CHECK PSN",
  38        [COMPST_CHECK_ACK]              = "CHECK ACK",
  39        [COMPST_READ]                   = "READ",
  40        [COMPST_ATOMIC]                 = "ATOMIC",
  41        [COMPST_WRITE_SEND]             = "WRITE/SEND",
  42        [COMPST_UPDATE_COMP]            = "UPDATE COMP",
  43        [COMPST_ERROR_RETRY]            = "ERROR RETRY",
  44        [COMPST_RNR_RETRY]              = "RNR RETRY",
  45        [COMPST_ERROR]                  = "ERROR",
  46        [COMPST_EXIT]                   = "EXIT",
  47        [COMPST_DONE]                   = "DONE",
  48};
  49
  50static unsigned long rnrnak_usec[32] = {
  51        [IB_RNR_TIMER_655_36] = 655360,
  52        [IB_RNR_TIMER_000_01] = 10,
  53        [IB_RNR_TIMER_000_02] = 20,
  54        [IB_RNR_TIMER_000_03] = 30,
  55        [IB_RNR_TIMER_000_04] = 40,
  56        [IB_RNR_TIMER_000_06] = 60,
  57        [IB_RNR_TIMER_000_08] = 80,
  58        [IB_RNR_TIMER_000_12] = 120,
  59        [IB_RNR_TIMER_000_16] = 160,
  60        [IB_RNR_TIMER_000_24] = 240,
  61        [IB_RNR_TIMER_000_32] = 320,
  62        [IB_RNR_TIMER_000_48] = 480,
  63        [IB_RNR_TIMER_000_64] = 640,
  64        [IB_RNR_TIMER_000_96] = 960,
  65        [IB_RNR_TIMER_001_28] = 1280,
  66        [IB_RNR_TIMER_001_92] = 1920,
  67        [IB_RNR_TIMER_002_56] = 2560,
  68        [IB_RNR_TIMER_003_84] = 3840,
  69        [IB_RNR_TIMER_005_12] = 5120,
  70        [IB_RNR_TIMER_007_68] = 7680,
  71        [IB_RNR_TIMER_010_24] = 10240,
  72        [IB_RNR_TIMER_015_36] = 15360,
  73        [IB_RNR_TIMER_020_48] = 20480,
  74        [IB_RNR_TIMER_030_72] = 30720,
  75        [IB_RNR_TIMER_040_96] = 40960,
  76        [IB_RNR_TIMER_061_44] = 61410,
  77        [IB_RNR_TIMER_081_92] = 81920,
  78        [IB_RNR_TIMER_122_88] = 122880,
  79        [IB_RNR_TIMER_163_84] = 163840,
  80        [IB_RNR_TIMER_245_76] = 245760,
  81        [IB_RNR_TIMER_327_68] = 327680,
  82        [IB_RNR_TIMER_491_52] = 491520,
  83};
  84
  85static inline unsigned long rnrnak_jiffies(u8 timeout)
  86{
  87        return max_t(unsigned long,
  88                usecs_to_jiffies(rnrnak_usec[timeout]), 1);
  89}
  90
  91static enum ib_wc_opcode wr_to_wc_opcode(enum ib_wr_opcode opcode)
  92{
  93        switch (opcode) {
  94        case IB_WR_RDMA_WRITE:                  return IB_WC_RDMA_WRITE;
  95        case IB_WR_RDMA_WRITE_WITH_IMM:         return IB_WC_RDMA_WRITE;
  96        case IB_WR_SEND:                        return IB_WC_SEND;
  97        case IB_WR_SEND_WITH_IMM:               return IB_WC_SEND;
  98        case IB_WR_RDMA_READ:                   return IB_WC_RDMA_READ;
  99        case IB_WR_ATOMIC_CMP_AND_SWP:          return IB_WC_COMP_SWAP;
 100        case IB_WR_ATOMIC_FETCH_AND_ADD:        return IB_WC_FETCH_ADD;
 101        case IB_WR_LSO:                         return IB_WC_LSO;
 102        case IB_WR_SEND_WITH_INV:               return IB_WC_SEND;
 103        case IB_WR_RDMA_READ_WITH_INV:          return IB_WC_RDMA_READ;
 104        case IB_WR_LOCAL_INV:                   return IB_WC_LOCAL_INV;
 105        case IB_WR_REG_MR:                      return IB_WC_REG_MR;
 106        case IB_WR_BIND_MW:                     return IB_WC_BIND_MW;
 107
 108        default:
 109                return 0xff;
 110        }
 111}
 112
 113void retransmit_timer(struct timer_list *t)
 114{
 115        struct rxe_qp *qp = from_timer(qp, t, retrans_timer);
 116
 117        if (qp->valid) {
 118                qp->comp.timeout = 1;
 119                rxe_run_task(&qp->comp.task, 1);
 120        }
 121}
 122
 123void rxe_comp_queue_pkt(struct rxe_qp *qp, struct sk_buff *skb)
 124{
 125        int must_sched;
 126
 127        skb_queue_tail(&qp->resp_pkts, skb);
 128
 129        must_sched = skb_queue_len(&qp->resp_pkts) > 1;
 130        if (must_sched != 0)
 131                rxe_counter_inc(SKB_TO_PKT(skb)->rxe, RXE_CNT_COMPLETER_SCHED);
 132
 133        rxe_run_task(&qp->comp.task, must_sched);
 134}
 135
 136static inline enum comp_state get_wqe(struct rxe_qp *qp,
 137                                      struct rxe_pkt_info *pkt,
 138                                      struct rxe_send_wqe **wqe_p)
 139{
 140        struct rxe_send_wqe *wqe;
 141
 142        /* we come here whether or not we found a response packet to see if
 143         * there are any posted WQEs
 144         */
 145        if (qp->is_user)
 146                wqe = queue_head(qp->sq.queue, QUEUE_TYPE_FROM_USER);
 147        else
 148                wqe = queue_head(qp->sq.queue, QUEUE_TYPE_KERNEL);
 149        *wqe_p = wqe;
 150
 151        /* no WQE or requester has not started it yet */
 152        if (!wqe || wqe->state == wqe_state_posted)
 153                return pkt ? COMPST_DONE : COMPST_EXIT;
 154
 155        /* WQE does not require an ack */
 156        if (wqe->state == wqe_state_done)
 157                return COMPST_COMP_WQE;
 158
 159        /* WQE caused an error */
 160        if (wqe->state == wqe_state_error)
 161                return COMPST_ERROR;
 162
 163        /* we have a WQE, if we also have an ack check its PSN */
 164        return pkt ? COMPST_CHECK_PSN : COMPST_EXIT;
 165}
 166
 167static inline void reset_retry_counters(struct rxe_qp *qp)
 168{
 169        qp->comp.retry_cnt = qp->attr.retry_cnt;
 170        qp->comp.rnr_retry = qp->attr.rnr_retry;
 171        qp->comp.started_retry = 0;
 172}
 173
 174static inline enum comp_state check_psn(struct rxe_qp *qp,
 175                                        struct rxe_pkt_info *pkt,
 176                                        struct rxe_send_wqe *wqe)
 177{
 178        s32 diff;
 179
 180        /* check to see if response is past the oldest WQE. if it is, complete
 181         * send/write or error read/atomic
 182         */
 183        diff = psn_compare(pkt->psn, wqe->last_psn);
 184        if (diff > 0) {
 185                if (wqe->state == wqe_state_pending) {
 186                        if (wqe->mask & WR_ATOMIC_OR_READ_MASK)
 187                                return COMPST_ERROR_RETRY;
 188
 189                        reset_retry_counters(qp);
 190                        return COMPST_COMP_WQE;
 191                } else {
 192                        return COMPST_DONE;
 193                }
 194        }
 195
 196        /* compare response packet to expected response */
 197        diff = psn_compare(pkt->psn, qp->comp.psn);
 198        if (diff < 0) {
 199                /* response is most likely a retried packet if it matches an
 200                 * uncompleted WQE go complete it else ignore it
 201                 */
 202                if (pkt->psn == wqe->last_psn)
 203                        return COMPST_COMP_ACK;
 204                else
 205                        return COMPST_DONE;
 206        } else if ((diff > 0) && (wqe->mask & WR_ATOMIC_OR_READ_MASK)) {
 207                return COMPST_DONE;
 208        } else {
 209                return COMPST_CHECK_ACK;
 210        }
 211}
 212
 213static inline enum comp_state check_ack(struct rxe_qp *qp,
 214                                        struct rxe_pkt_info *pkt,
 215                                        struct rxe_send_wqe *wqe)
 216{
 217        unsigned int mask = pkt->mask;
 218        u8 syn;
 219        struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
 220
 221        /* Check the sequence only */
 222        switch (qp->comp.opcode) {
 223        case -1:
 224                /* Will catch all *_ONLY cases. */
 225                if (!(mask & RXE_START_MASK))
 226                        return COMPST_ERROR;
 227
 228                break;
 229
 230        case IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST:
 231        case IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE:
 232                if (pkt->opcode != IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE &&
 233                    pkt->opcode != IB_OPCODE_RC_RDMA_READ_RESPONSE_LAST) {
 234                        /* read retries of partial data may restart from
 235                         * read response first or response only.
 236                         */
 237                        if ((pkt->psn == wqe->first_psn &&
 238                             pkt->opcode ==
 239                             IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST) ||
 240                            (wqe->first_psn == wqe->last_psn &&
 241                             pkt->opcode ==
 242                             IB_OPCODE_RC_RDMA_READ_RESPONSE_ONLY))
 243                                break;
 244
 245                        return COMPST_ERROR;
 246                }
 247                break;
 248        default:
 249                WARN_ON_ONCE(1);
 250        }
 251
 252        /* Check operation validity. */
 253        switch (pkt->opcode) {
 254        case IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST:
 255        case IB_OPCODE_RC_RDMA_READ_RESPONSE_LAST:
 256        case IB_OPCODE_RC_RDMA_READ_RESPONSE_ONLY:
 257                syn = aeth_syn(pkt);
 258
 259                if ((syn & AETH_TYPE_MASK) != AETH_ACK)
 260                        return COMPST_ERROR;
 261
 262                fallthrough;
 263                /* (IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE doesn't have an AETH)
 264                 */
 265        case IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE:
 266                if (wqe->wr.opcode != IB_WR_RDMA_READ &&
 267                    wqe->wr.opcode != IB_WR_RDMA_READ_WITH_INV) {
 268                        wqe->status = IB_WC_FATAL_ERR;
 269                        return COMPST_ERROR;
 270                }
 271                reset_retry_counters(qp);
 272                return COMPST_READ;
 273
 274        case IB_OPCODE_RC_ATOMIC_ACKNOWLEDGE:
 275                syn = aeth_syn(pkt);
 276
 277                if ((syn & AETH_TYPE_MASK) != AETH_ACK)
 278                        return COMPST_ERROR;
 279
 280                if (wqe->wr.opcode != IB_WR_ATOMIC_CMP_AND_SWP &&
 281                    wqe->wr.opcode != IB_WR_ATOMIC_FETCH_AND_ADD)
 282                        return COMPST_ERROR;
 283                reset_retry_counters(qp);
 284                return COMPST_ATOMIC;
 285
 286        case IB_OPCODE_RC_ACKNOWLEDGE:
 287                syn = aeth_syn(pkt);
 288                switch (syn & AETH_TYPE_MASK) {
 289                case AETH_ACK:
 290                        reset_retry_counters(qp);
 291                        return COMPST_WRITE_SEND;
 292
 293                case AETH_RNR_NAK:
 294                        rxe_counter_inc(rxe, RXE_CNT_RCV_RNR);
 295                        return COMPST_RNR_RETRY;
 296
 297                case AETH_NAK:
 298                        switch (syn) {
 299                        case AETH_NAK_PSN_SEQ_ERROR:
 300                                /* a nak implicitly acks all packets with psns
 301                                 * before
 302                                 */
 303                                if (psn_compare(pkt->psn, qp->comp.psn) > 0) {
 304                                        rxe_counter_inc(rxe,
 305                                                        RXE_CNT_RCV_SEQ_ERR);
 306                                        qp->comp.psn = pkt->psn;
 307                                        if (qp->req.wait_psn) {
 308                                                qp->req.wait_psn = 0;
 309                                                rxe_run_task(&qp->req.task, 0);
 310                                        }
 311                                }
 312                                return COMPST_ERROR_RETRY;
 313
 314                        case AETH_NAK_INVALID_REQ:
 315                                wqe->status = IB_WC_REM_INV_REQ_ERR;
 316                                return COMPST_ERROR;
 317
 318                        case AETH_NAK_REM_ACC_ERR:
 319                                wqe->status = IB_WC_REM_ACCESS_ERR;
 320                                return COMPST_ERROR;
 321
 322                        case AETH_NAK_REM_OP_ERR:
 323                                wqe->status = IB_WC_REM_OP_ERR;
 324                                return COMPST_ERROR;
 325
 326                        default:
 327                                pr_warn("unexpected nak %x\n", syn);
 328                                wqe->status = IB_WC_REM_OP_ERR;
 329                                return COMPST_ERROR;
 330                        }
 331
 332                default:
 333                        return COMPST_ERROR;
 334                }
 335                break;
 336
 337        default:
 338                pr_warn("unexpected opcode\n");
 339        }
 340
 341        return COMPST_ERROR;
 342}
 343
 344static inline enum comp_state do_read(struct rxe_qp *qp,
 345                                      struct rxe_pkt_info *pkt,
 346                                      struct rxe_send_wqe *wqe)
 347{
 348        int ret;
 349
 350        ret = copy_data(qp->pd, IB_ACCESS_LOCAL_WRITE,
 351                        &wqe->dma, payload_addr(pkt),
 352                        payload_size(pkt), RXE_TO_MR_OBJ);
 353        if (ret) {
 354                wqe->status = IB_WC_LOC_PROT_ERR;
 355                return COMPST_ERROR;
 356        }
 357
 358        if (wqe->dma.resid == 0 && (pkt->mask & RXE_END_MASK))
 359                return COMPST_COMP_ACK;
 360
 361        return COMPST_UPDATE_COMP;
 362}
 363
 364static inline enum comp_state do_atomic(struct rxe_qp *qp,
 365                                        struct rxe_pkt_info *pkt,
 366                                        struct rxe_send_wqe *wqe)
 367{
 368        int ret;
 369
 370        u64 atomic_orig = atmack_orig(pkt);
 371
 372        ret = copy_data(qp->pd, IB_ACCESS_LOCAL_WRITE,
 373                        &wqe->dma, &atomic_orig,
 374                        sizeof(u64), RXE_TO_MR_OBJ);
 375        if (ret) {
 376                wqe->status = IB_WC_LOC_PROT_ERR;
 377                return COMPST_ERROR;
 378        }
 379
 380        return COMPST_COMP_ACK;
 381}
 382
 383static void make_send_cqe(struct rxe_qp *qp, struct rxe_send_wqe *wqe,
 384                          struct rxe_cqe *cqe)
 385{
 386        memset(cqe, 0, sizeof(*cqe));
 387
 388        if (!qp->is_user) {
 389                struct ib_wc            *wc     = &cqe->ibwc;
 390
 391                wc->wr_id               = wqe->wr.wr_id;
 392                wc->status              = wqe->status;
 393                wc->opcode              = wr_to_wc_opcode(wqe->wr.opcode);
 394                if (wqe->wr.opcode == IB_WR_RDMA_WRITE_WITH_IMM ||
 395                    wqe->wr.opcode == IB_WR_SEND_WITH_IMM)
 396                        wc->wc_flags = IB_WC_WITH_IMM;
 397                wc->byte_len            = wqe->dma.length;
 398                wc->qp                  = &qp->ibqp;
 399        } else {
 400                struct ib_uverbs_wc     *uwc    = &cqe->uibwc;
 401
 402                uwc->wr_id              = wqe->wr.wr_id;
 403                uwc->status             = wqe->status;
 404                uwc->opcode             = wr_to_wc_opcode(wqe->wr.opcode);
 405                if (wqe->wr.opcode == IB_WR_RDMA_WRITE_WITH_IMM ||
 406                    wqe->wr.opcode == IB_WR_SEND_WITH_IMM)
 407                        uwc->wc_flags = IB_WC_WITH_IMM;
 408                uwc->byte_len           = wqe->dma.length;
 409                uwc->qp_num             = qp->ibqp.qp_num;
 410        }
 411}
 412
 413/*
 414 * IBA Spec. Section 10.7.3.1 SIGNALED COMPLETIONS
 415 * ---------8<---------8<-------------
 416 * ...Note that if a completion error occurs, a Work Completion
 417 * will always be generated, even if the signaling
 418 * indicator requests an Unsignaled Completion.
 419 * ---------8<---------8<-------------
 420 */
 421static void do_complete(struct rxe_qp *qp, struct rxe_send_wqe *wqe)
 422{
 423        struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
 424        struct rxe_cqe cqe;
 425        bool post;
 426
 427        /* do we need to post a completion */
 428        post = ((qp->sq_sig_type == IB_SIGNAL_ALL_WR) ||
 429                        (wqe->wr.send_flags & IB_SEND_SIGNALED) ||
 430                        wqe->status != IB_WC_SUCCESS);
 431
 432        if (post)
 433                make_send_cqe(qp, wqe, &cqe);
 434
 435        if (qp->is_user)
 436                advance_consumer(qp->sq.queue, QUEUE_TYPE_FROM_USER);
 437        else
 438                advance_consumer(qp->sq.queue, QUEUE_TYPE_KERNEL);
 439
 440        if (post)
 441                rxe_cq_post(qp->scq, &cqe, 0);
 442
 443        if (wqe->wr.opcode == IB_WR_SEND ||
 444            wqe->wr.opcode == IB_WR_SEND_WITH_IMM ||
 445            wqe->wr.opcode == IB_WR_SEND_WITH_INV)
 446                rxe_counter_inc(rxe, RXE_CNT_RDMA_SEND);
 447
 448        /*
 449         * we completed something so let req run again
 450         * if it is trying to fence
 451         */
 452        if (qp->req.wait_fence) {
 453                qp->req.wait_fence = 0;
 454                rxe_run_task(&qp->req.task, 0);
 455        }
 456}
 457
 458static inline enum comp_state complete_ack(struct rxe_qp *qp,
 459                                           struct rxe_pkt_info *pkt,
 460                                           struct rxe_send_wqe *wqe)
 461{
 462        unsigned long flags;
 463
 464        if (wqe->has_rd_atomic) {
 465                wqe->has_rd_atomic = 0;
 466                atomic_inc(&qp->req.rd_atomic);
 467                if (qp->req.need_rd_atomic) {
 468                        qp->comp.timeout_retry = 0;
 469                        qp->req.need_rd_atomic = 0;
 470                        rxe_run_task(&qp->req.task, 0);
 471                }
 472        }
 473
 474        if (unlikely(qp->req.state == QP_STATE_DRAIN)) {
 475                /* state_lock used by requester & completer */
 476                spin_lock_irqsave(&qp->state_lock, flags);
 477                if ((qp->req.state == QP_STATE_DRAIN) &&
 478                    (qp->comp.psn == qp->req.psn)) {
 479                        qp->req.state = QP_STATE_DRAINED;
 480                        spin_unlock_irqrestore(&qp->state_lock, flags);
 481
 482                        if (qp->ibqp.event_handler) {
 483                                struct ib_event ev;
 484
 485                                ev.device = qp->ibqp.device;
 486                                ev.element.qp = &qp->ibqp;
 487                                ev.event = IB_EVENT_SQ_DRAINED;
 488                                qp->ibqp.event_handler(&ev,
 489                                        qp->ibqp.qp_context);
 490                        }
 491                } else {
 492                        spin_unlock_irqrestore(&qp->state_lock, flags);
 493                }
 494        }
 495
 496        do_complete(qp, wqe);
 497
 498        if (psn_compare(pkt->psn, qp->comp.psn) >= 0)
 499                return COMPST_UPDATE_COMP;
 500        else
 501                return COMPST_DONE;
 502}
 503
 504static inline enum comp_state complete_wqe(struct rxe_qp *qp,
 505                                           struct rxe_pkt_info *pkt,
 506                                           struct rxe_send_wqe *wqe)
 507{
 508        if (pkt && wqe->state == wqe_state_pending) {
 509                if (psn_compare(wqe->last_psn, qp->comp.psn) >= 0) {
 510                        qp->comp.psn = (wqe->last_psn + 1) & BTH_PSN_MASK;
 511                        qp->comp.opcode = -1;
 512                }
 513
 514                if (qp->req.wait_psn) {
 515                        qp->req.wait_psn = 0;
 516                        rxe_run_task(&qp->req.task, 1);
 517                }
 518        }
 519
 520        do_complete(qp, wqe);
 521
 522        return COMPST_GET_WQE;
 523}
 524
 525static void rxe_drain_resp_pkts(struct rxe_qp *qp, bool notify)
 526{
 527        struct sk_buff *skb;
 528        struct rxe_send_wqe *wqe;
 529        struct rxe_queue *q = qp->sq.queue;
 530
 531        while ((skb = skb_dequeue(&qp->resp_pkts))) {
 532                rxe_drop_ref(qp);
 533                kfree_skb(skb);
 534                ib_device_put(qp->ibqp.device);
 535        }
 536
 537        while ((wqe = queue_head(q, q->type))) {
 538                if (notify) {
 539                        wqe->status = IB_WC_WR_FLUSH_ERR;
 540                        do_complete(qp, wqe);
 541                } else {
 542                        advance_consumer(q, q->type);
 543                }
 544        }
 545}
 546
 547static void free_pkt(struct rxe_pkt_info *pkt)
 548{
 549        struct sk_buff *skb = PKT_TO_SKB(pkt);
 550        struct rxe_qp *qp = pkt->qp;
 551        struct ib_device *dev = qp->ibqp.device;
 552
 553        kfree_skb(skb);
 554        rxe_drop_ref(qp);
 555        ib_device_put(dev);
 556}
 557
 558int rxe_completer(void *arg)
 559{
 560        struct rxe_qp *qp = (struct rxe_qp *)arg;
 561        struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
 562        struct rxe_send_wqe *wqe = NULL;
 563        struct sk_buff *skb = NULL;
 564        struct rxe_pkt_info *pkt = NULL;
 565        enum comp_state state;
 566        int ret = 0;
 567
 568        rxe_add_ref(qp);
 569
 570        if (!qp->valid || qp->req.state == QP_STATE_ERROR ||
 571            qp->req.state == QP_STATE_RESET) {
 572                rxe_drain_resp_pkts(qp, qp->valid &&
 573                                    qp->req.state == QP_STATE_ERROR);
 574                ret = -EAGAIN;
 575                goto done;
 576        }
 577
 578        if (qp->comp.timeout) {
 579                qp->comp.timeout_retry = 1;
 580                qp->comp.timeout = 0;
 581        } else {
 582                qp->comp.timeout_retry = 0;
 583        }
 584
 585        if (qp->req.need_retry) {
 586                ret = -EAGAIN;
 587                goto done;
 588        }
 589
 590        state = COMPST_GET_ACK;
 591
 592        while (1) {
 593                pr_debug("qp#%d state = %s\n", qp_num(qp),
 594                         comp_state_name[state]);
 595                switch (state) {
 596                case COMPST_GET_ACK:
 597                        skb = skb_dequeue(&qp->resp_pkts);
 598                        if (skb) {
 599                                pkt = SKB_TO_PKT(skb);
 600                                qp->comp.timeout_retry = 0;
 601                        }
 602                        state = COMPST_GET_WQE;
 603                        break;
 604
 605                case COMPST_GET_WQE:
 606                        state = get_wqe(qp, pkt, &wqe);
 607                        break;
 608
 609                case COMPST_CHECK_PSN:
 610                        state = check_psn(qp, pkt, wqe);
 611                        break;
 612
 613                case COMPST_CHECK_ACK:
 614                        state = check_ack(qp, pkt, wqe);
 615                        break;
 616
 617                case COMPST_READ:
 618                        state = do_read(qp, pkt, wqe);
 619                        break;
 620
 621                case COMPST_ATOMIC:
 622                        state = do_atomic(qp, pkt, wqe);
 623                        break;
 624
 625                case COMPST_WRITE_SEND:
 626                        if (wqe->state == wqe_state_pending &&
 627                            wqe->last_psn == pkt->psn)
 628                                state = COMPST_COMP_ACK;
 629                        else
 630                                state = COMPST_UPDATE_COMP;
 631                        break;
 632
 633                case COMPST_COMP_ACK:
 634                        state = complete_ack(qp, pkt, wqe);
 635                        break;
 636
 637                case COMPST_COMP_WQE:
 638                        state = complete_wqe(qp, pkt, wqe);
 639                        break;
 640
 641                case COMPST_UPDATE_COMP:
 642                        if (pkt->mask & RXE_END_MASK)
 643                                qp->comp.opcode = -1;
 644                        else
 645                                qp->comp.opcode = pkt->opcode;
 646
 647                        if (psn_compare(pkt->psn, qp->comp.psn) >= 0)
 648                                qp->comp.psn = (pkt->psn + 1) & BTH_PSN_MASK;
 649
 650                        if (qp->req.wait_psn) {
 651                                qp->req.wait_psn = 0;
 652                                rxe_run_task(&qp->req.task, 1);
 653                        }
 654
 655                        state = COMPST_DONE;
 656                        break;
 657
 658                case COMPST_DONE:
 659                        goto done;
 660
 661                case COMPST_EXIT:
 662                        if (qp->comp.timeout_retry && wqe) {
 663                                state = COMPST_ERROR_RETRY;
 664                                break;
 665                        }
 666
 667                        /* re reset the timeout counter if
 668                         * (1) QP is type RC
 669                         * (2) the QP is alive
 670                         * (3) there is a packet sent by the requester that
 671                         *     might be acked (we still might get spurious
 672                         *     timeouts but try to keep them as few as possible)
 673                         * (4) the timeout parameter is set
 674                         */
 675                        if ((qp_type(qp) == IB_QPT_RC) &&
 676                            (qp->req.state == QP_STATE_READY) &&
 677                            (psn_compare(qp->req.psn, qp->comp.psn) > 0) &&
 678                            qp->qp_timeout_jiffies)
 679                                mod_timer(&qp->retrans_timer,
 680                                          jiffies + qp->qp_timeout_jiffies);
 681                        ret = -EAGAIN;
 682                        goto done;
 683
 684                case COMPST_ERROR_RETRY:
 685                        /* we come here if the retry timer fired and we did
 686                         * not receive a response packet. try to retry the send
 687                         * queue if that makes sense and the limits have not
 688                         * been exceeded. remember that some timeouts are
 689                         * spurious since we do not reset the timer but kick
 690                         * it down the road or let it expire
 691                         */
 692
 693                        /* there is nothing to retry in this case */
 694                        if (!wqe || (wqe->state == wqe_state_posted)) {
 695                                ret = -EAGAIN;
 696                                goto done;
 697                        }
 698
 699                        /* if we've started a retry, don't start another
 700                         * retry sequence, unless this is a timeout.
 701                         */
 702                        if (qp->comp.started_retry &&
 703                            !qp->comp.timeout_retry)
 704                                goto done;
 705
 706                        if (qp->comp.retry_cnt > 0) {
 707                                if (qp->comp.retry_cnt != 7)
 708                                        qp->comp.retry_cnt--;
 709
 710                                /* no point in retrying if we have already
 711                                 * seen the last ack that the requester could
 712                                 * have caused
 713                                 */
 714                                if (psn_compare(qp->req.psn,
 715                                                qp->comp.psn) > 0) {
 716                                        /* tell the requester to retry the
 717                                         * send queue next time around
 718                                         */
 719                                        rxe_counter_inc(rxe,
 720                                                        RXE_CNT_COMP_RETRY);
 721                                        qp->req.need_retry = 1;
 722                                        qp->comp.started_retry = 1;
 723                                        rxe_run_task(&qp->req.task, 0);
 724                                }
 725                                goto done;
 726
 727                        } else {
 728                                rxe_counter_inc(rxe, RXE_CNT_RETRY_EXCEEDED);
 729                                wqe->status = IB_WC_RETRY_EXC_ERR;
 730                                state = COMPST_ERROR;
 731                        }
 732                        break;
 733
 734                case COMPST_RNR_RETRY:
 735                        if (qp->comp.rnr_retry > 0) {
 736                                if (qp->comp.rnr_retry != 7)
 737                                        qp->comp.rnr_retry--;
 738
 739                                qp->req.need_retry = 1;
 740                                pr_debug("qp#%d set rnr nak timer\n",
 741                                         qp_num(qp));
 742                                mod_timer(&qp->rnr_nak_timer,
 743                                          jiffies + rnrnak_jiffies(aeth_syn(pkt)
 744                                                & ~AETH_TYPE_MASK));
 745                                ret = -EAGAIN;
 746                                goto done;
 747                        } else {
 748                                rxe_counter_inc(rxe,
 749                                                RXE_CNT_RNR_RETRY_EXCEEDED);
 750                                wqe->status = IB_WC_RNR_RETRY_EXC_ERR;
 751                                state = COMPST_ERROR;
 752                        }
 753                        break;
 754
 755                case COMPST_ERROR:
 756                        WARN_ON_ONCE(wqe->status == IB_WC_SUCCESS);
 757                        do_complete(qp, wqe);
 758                        rxe_qp_error(qp);
 759                        ret = -EAGAIN;
 760                        goto done;
 761                }
 762        }
 763
 764done:
 765        if (pkt)
 766                free_pkt(pkt);
 767        rxe_drop_ref(qp);
 768
 769        return ret;
 770}
 771