drivers/infiniband/hw/qib/qib_rc.c

   1 /*
   2  * Copyright (c) 2006, 2007, 2008, 2009 QLogic Corporation. All rights reserved.
   3  * Copyright (c) 2005, 2006 PathScale, 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/io.h>
  35
  36 #include "qib.h"
  37
  38 /* cut down ridiculously long IB macro names */
  39 #define OP(x) IB_OPCODE_RC_##x
  40
  41 static void rc_timeout(unsigned long arg);
  42
  43 static u32 restart_sge(struct rvt_sge_state *ss, struct rvt_swqe *wqe,
  44                        u32 psn, u32 pmtu)
  45 {
  46         u32 len;
  47
  48         len = ((psn - wqe->psn) & QIB_PSN_MASK) * pmtu;
  49         ss->sge = wqe->sg_list[0];
  50         ss->sg_list = wqe->sg_list + 1;
  51         ss->num_sge = wqe->wr.num_sge;
  52         ss->total_len = wqe->length;
  53         qib_skip_sge(ss, len, 0);
  54         return wqe->length - len;
  55 }
  56
  57 static void start_timer(struct rvt_qp *qp)
  58 {
  59         qp->s_flags |= RVT_S_TIMER;
  60         qp->s_timer.function = rc_timeout;
  61         /* 4.096 usec. * (1 << qp->timeout) */
  62         qp->s_timer.expires = jiffies + qp->timeout_jiffies;
  63         add_timer(&qp->s_timer);
  64 }
  65
  66 /**
  67  * qib_make_rc_ack - construct a response packet (ACK, NAK, or RDMA read)
  68  * @dev: the device for this QP
  69  * @qp: a pointer to the QP
  70  * @ohdr: a pointer to the IB header being constructed
  71  * @pmtu: the path MTU
  72  *
  73  * Return 1 if constructed; otherwise, return 0.
  74  * Note that we are in the responder's side of the QP context.
  75  * Note the QP s_lock must be held.
  76  */
  77 static int qib_make_rc_ack(struct qib_ibdev *dev, struct rvt_qp *qp,
  78                            struct ib_other_headers *ohdr, u32 pmtu)
  79 {
  80         struct rvt_ack_entry *e;
  81         u32 hwords;
  82         u32 len;
  83         u32 bth0;
  84         u32 bth2;
  85
  86         /* Don't send an ACK if we aren't supposed to. */
  87         if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK))
  88                 goto bail;
  89
  90         /* header size in 32-bit words LRH+BTH = (8+12)/4. */
  91         hwords = 5;
  92
  93         switch (qp->s_ack_state) {
  94         case OP(RDMA_READ_RESPONSE_LAST):
  95         case OP(RDMA_READ_RESPONSE_ONLY):
  96                 e = &qp->s_ack_queue[qp->s_tail_ack_queue];
  97                 if (e->rdma_sge.mr) {
  98                         rvt_put_mr(e->rdma_sge.mr);
  99                         e->rdma_sge.mr = NULL;
 100                 }
 101                 /* FALLTHROUGH */
 102         case OP(ATOMIC_ACKNOWLEDGE):
 103                 /*
 104                  * We can increment the tail pointer now that the last
 105                  * response has been sent instead of only being
 106                  * constructed.
 107                  */
 108                 if (++qp->s_tail_ack_queue > QIB_MAX_RDMA_ATOMIC)
 109                         qp->s_tail_ack_queue = 0;
 110                 /* FALLTHROUGH */
 111         case OP(SEND_ONLY):
 112         case OP(ACKNOWLEDGE):
 113                 /* Check for no next entry in the queue. */
 114                 if (qp->r_head_ack_queue == qp->s_tail_ack_queue) {
 115                         if (qp->s_flags & RVT_S_ACK_PENDING)
 116                                 goto normal;
 117                         goto bail;
 118                 }
 119
 120                 e = &qp->s_ack_queue[qp->s_tail_ack_queue];
 121                 if (e->opcode == OP(RDMA_READ_REQUEST)) {
 122                         /*
 123                          * If a RDMA read response is being resent and
 124                          * we haven't seen the duplicate request yet,
 125                          * then stop sending the remaining responses the
 126                          * responder has seen until the requester resends it.
 127                          */
 128                         len = e->rdma_sge.sge_length;
 129                         if (len && !e->rdma_sge.mr) {
 130                                 qp->s_tail_ack_queue = qp->r_head_ack_queue;
 131                                 goto bail;
 132                         }
 133                         /* Copy SGE state in case we need to resend */
 134                         qp->s_rdma_mr = e->rdma_sge.mr;
 135                         if (qp->s_rdma_mr)
 136                                 rvt_get_mr(qp->s_rdma_mr);
 137                         qp->s_ack_rdma_sge.sge = e->rdma_sge;
 138                         qp->s_ack_rdma_sge.num_sge = 1;
 139                         qp->s_cur_sge = &qp->s_ack_rdma_sge;
 140                         if (len > pmtu) {
 141                                 len = pmtu;
 142                                 qp->s_ack_state = OP(RDMA_READ_RESPONSE_FIRST);
 143                         } else {
 144                                 qp->s_ack_state = OP(RDMA_READ_RESPONSE_ONLY);
 145                                 e->sent = 1;
 146                         }
 147                         ohdr->u.aeth = qib_compute_aeth(qp);
 148                         hwords++;
 149                         qp->s_ack_rdma_psn = e->psn;
 150                         bth2 = qp->s_ack_rdma_psn++ & QIB_PSN_MASK;
 151                 } else {
 152                         /* COMPARE_SWAP or FETCH_ADD */
 153                         qp->s_cur_sge = NULL;
 154                         len = 0;
 155                         qp->s_ack_state = OP(ATOMIC_ACKNOWLEDGE);
 156                         ohdr->u.at.aeth = qib_compute_aeth(qp);
 157                         ib_u64_put(e->atomic_data, &ohdr->u.at.atomic_ack_eth);
 158                         hwords += sizeof(ohdr->u.at) / sizeof(u32);
 159                         bth2 = e->psn & QIB_PSN_MASK;
 160                         e->sent = 1;
 161                 }
 162                 bth0 = qp->s_ack_state << 24;
 163                 break;
 164
 165         case OP(RDMA_READ_RESPONSE_FIRST):
 166                 qp->s_ack_state = OP(RDMA_READ_RESPONSE_MIDDLE);
 167                 /* FALLTHROUGH */
 168         case OP(RDMA_READ_RESPONSE_MIDDLE):
 169                 qp->s_cur_sge = &qp->s_ack_rdma_sge;
 170                 qp->s_rdma_mr = qp->s_ack_rdma_sge.sge.mr;
 171                 if (qp->s_rdma_mr)
 172                         rvt_get_mr(qp->s_rdma_mr);
 173                 len = qp->s_ack_rdma_sge.sge.sge_length;
 174                 if (len > pmtu)
 175                         len = pmtu;
 176                 else {
 177                         ohdr->u.aeth = qib_compute_aeth(qp);
 178                         hwords++;
 179                         qp->s_ack_state = OP(RDMA_READ_RESPONSE_LAST);
 180                         e = &qp->s_ack_queue[qp->s_tail_ack_queue];
 181                         e->sent = 1;
 182                 }
 183                 bth0 = qp->s_ack_state << 24;
 184                 bth2 = qp->s_ack_rdma_psn++ & QIB_PSN_MASK;
 185                 break;
 186
 187         default:
 188 normal:
 189                 /*
 190                  * Send a regular ACK.
 191                  * Set the s_ack_state so we wait until after sending
 192                  * the ACK before setting s_ack_state to ACKNOWLEDGE
 193                  * (see above).
 194                  */
 195                 qp->s_ack_state = OP(SEND_ONLY);
 196                 qp->s_flags &= ~RVT_S_ACK_PENDING;
 197                 qp->s_cur_sge = NULL;
 198                 if (qp->s_nak_state)
 199                         ohdr->u.aeth =
 200                                 cpu_to_be32((qp->r_msn & QIB_MSN_MASK) |
 201                                             (qp->s_nak_state <<
 202                                              QIB_AETH_CREDIT_SHIFT));
 203                 else
 204                         ohdr->u.aeth = qib_compute_aeth(qp);
 205                 hwords++;
 206                 len = 0;
 207                 bth0 = OP(ACKNOWLEDGE) << 24;
 208                 bth2 = qp->s_ack_psn & QIB_PSN_MASK;
 209         }
 210         qp->s_rdma_ack_cnt++;
 211         qp->s_hdrwords = hwords;
 212         qp->s_cur_size = len;
 213         qib_make_ruc_header(qp, ohdr, bth0, bth2);
 214         return 1;
 215
 216 bail:
 217         qp->s_ack_state = OP(ACKNOWLEDGE);
 218         qp->s_flags &= ~(RVT_S_RESP_PENDING | RVT_S_ACK_PENDING);
 219         return 0;
 220 }
 221
 222 /**
 223  * qib_make_rc_req - construct a request packet (SEND, RDMA r/w, ATOMIC)
 224  * @qp: a pointer to the QP
 225  *
 226  * Assumes the s_lock is held.
 227  *
 228  * Return 1 if constructed; otherwise, return 0.
 229  */
 230 int qib_make_rc_req(struct rvt_qp *qp, unsigned long *flags)
 231 {
 232         struct qib_qp_priv *priv = qp->priv;
 233         struct qib_ibdev *dev = to_idev(qp->ibqp.device);
 234         struct ib_other_headers *ohdr;
 235         struct rvt_sge_state *ss;
 236         struct rvt_swqe *wqe;
 237         u32 hwords;
 238         u32 len;
 239         u32 bth0;
 240         u32 bth2;
 241         u32 pmtu = qp->pmtu;
 242         char newreq;
 243         int ret = 0;
 244         int delta;
 245
 246         ohdr = &priv->s_hdr->u.oth;
 247         if (qp->remote_ah_attr.ah_flags & IB_AH_GRH)
 248                 ohdr = &priv->s_hdr->u.l.oth;
 249
 250         /* Sending responses has higher priority over sending requests. */
 251         if ((qp->s_flags & RVT_S_RESP_PENDING) &&
 252             qib_make_rc_ack(dev, qp, ohdr, pmtu))
 253                 goto done;
 254
 255         if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_SEND_OK)) {
 256                 if (!(ib_rvt_state_ops[qp->state] & RVT_FLUSH_SEND))
 257                         goto bail;
 258                 /* We are in the error state, flush the work request. */
 259                 smp_read_barrier_depends(); /* see post_one_send() */
 260                 if (qp->s_last == ACCESS_ONCE(qp->s_head))
 261                         goto bail;
 262                 /* If DMAs are in progress, we can't flush immediately. */
 263                 if (atomic_read(&priv->s_dma_busy)) {
 264                         qp->s_flags |= RVT_S_WAIT_DMA;
 265                         goto bail;
 266                 }
 267                 wqe = rvt_get_swqe_ptr(qp, qp->s_last);
 268                 qib_send_complete(qp, wqe, qp->s_last != qp->s_acked ?
 269                         IB_WC_SUCCESS : IB_WC_WR_FLUSH_ERR);
 270                 /* will get called again */
 271                 goto done;
 272         }
 273
 274         if (qp->s_flags & (RVT_S_WAIT_RNR | RVT_S_WAIT_ACK))
 275                 goto bail;
 276
 277         if (qib_cmp24(qp->s_psn, qp->s_sending_hpsn) <= 0) {
 278                 if (qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) <= 0) {
 279                         qp->s_flags |= RVT_S_WAIT_PSN;
 280                         goto bail;
 281                 }
 282                 qp->s_sending_psn = qp->s_psn;
 283                 qp->s_sending_hpsn = qp->s_psn - 1;
 284         }
 285
 286         /* header size in 32-bit words LRH+BTH = (8+12)/4. */
 287         hwords = 5;
 288         bth0 = 0;
 289
 290         /* Send a request. */
 291         wqe = rvt_get_swqe_ptr(qp, qp->s_cur);
 292         switch (qp->s_state) {
 293         default:
 294                 if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_NEXT_SEND_OK))
 295                         goto bail;
 296                 /*
 297                  * Resend an old request or start a new one.
 298                  *
 299                  * We keep track of the current SWQE so that
 300                  * we don't reset the "furthest progress" state
 301                  * if we need to back up.
 302                  */
 303                 newreq = 0;
 304                 if (qp->s_cur == qp->s_tail) {
 305                         /* Check if send work queue is empty. */
 306                         if (qp->s_tail == qp->s_head)
 307                                 goto bail;
 308                         /*
 309                          * If a fence is requested, wait for previous
 310                          * RDMA read and atomic operations to finish.
 311                          */
 312                         if ((wqe->wr.send_flags & IB_SEND_FENCE) &&
 313                             qp->s_num_rd_atomic) {
 314                                 qp->s_flags |= RVT_S_WAIT_FENCE;
 315                                 goto bail;
 316                         }
 317                         newreq = 1;
 318                         qp->s_psn = wqe->psn;
 319                 }
 320                 /*
 321                  * Note that we have to be careful not to modify the
 322                  * original work request since we may need to resend
 323                  * it.
 324                  */
 325                 len = wqe->length;
 326                 ss = &qp->s_sge;
 327                 bth2 = qp->s_psn & QIB_PSN_MASK;
 328                 switch (wqe->wr.opcode) {
 329                 case IB_WR_SEND:
 330                 case IB_WR_SEND_WITH_IMM:
 331                         /* If no credit, return. */
 332                         if (!(qp->s_flags & RVT_S_UNLIMITED_CREDIT) &&
 333                             qib_cmp24(wqe->ssn, qp->s_lsn + 1) > 0) {
 334                                 qp->s_flags |= RVT_S_WAIT_SSN_CREDIT;
 335                                 goto bail;
 336                         }
 337                         if (len > pmtu) {
 338                                 qp->s_state = OP(SEND_FIRST);
 339                                 len = pmtu;
 340                                 break;
 341                         }
 342                         if (wqe->wr.opcode == IB_WR_SEND)
 343                                 qp->s_state = OP(SEND_ONLY);
 344                         else {
 345                                 qp->s_state = OP(SEND_ONLY_WITH_IMMEDIATE);
 346                                 /* Immediate data comes after the BTH */
 347                                 ohdr->u.imm_data = wqe->wr.ex.imm_data;
 348                                 hwords += 1;
 349                         }
 350                         if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 351                                 bth0 |= IB_BTH_SOLICITED;
 352                         bth2 |= IB_BTH_REQ_ACK;
 353                         if (++qp->s_cur == qp->s_size)
 354                                 qp->s_cur = 0;
 355                         break;
 356
 357                 case IB_WR_RDMA_WRITE:
 358                         if (newreq && !(qp->s_flags & RVT_S_UNLIMITED_CREDIT))
 359                                 qp->s_lsn++;
 360                         /* FALLTHROUGH */
 361                 case IB_WR_RDMA_WRITE_WITH_IMM:
 362                         /* If no credit, return. */
 363                         if (!(qp->s_flags & RVT_S_UNLIMITED_CREDIT) &&
 364                             qib_cmp24(wqe->ssn, qp->s_lsn + 1) > 0) {
 365                                 qp->s_flags |= RVT_S_WAIT_SSN_CREDIT;
 366                                 goto bail;
 367                         }
 368
 369                         ohdr->u.rc.reth.vaddr =
 370                                 cpu_to_be64(wqe->rdma_wr.remote_addr);
 371                         ohdr->u.rc.reth.rkey =
 372                                 cpu_to_be32(wqe->rdma_wr.rkey);
 373                         ohdr->u.rc.reth.length = cpu_to_be32(len);
 374                         hwords += sizeof(struct ib_reth) / sizeof(u32);
 375                         if (len > pmtu) {
 376                                 qp->s_state = OP(RDMA_WRITE_FIRST);
 377                                 len = pmtu;
 378                                 break;
 379                         }
 380                         if (wqe->rdma_wr.wr.opcode == IB_WR_RDMA_WRITE)
 381                                 qp->s_state = OP(RDMA_WRITE_ONLY);
 382                         else {
 383                                 qp->s_state = OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE);
 384                                 /* Immediate data comes after RETH */
 385                                 ohdr->u.rc.imm_data =
 386                                         wqe->rdma_wr.wr.ex.imm_data;
 387                                 hwords += 1;
 388                                 if (wqe->rdma_wr.wr.send_flags & IB_SEND_SOLICITED)
 389                                         bth0 |= IB_BTH_SOLICITED;
 390                         }
 391                         bth2 |= IB_BTH_REQ_ACK;
 392                         if (++qp->s_cur == qp->s_size)
 393                                 qp->s_cur = 0;
 394                         break;
 395
 396                 case IB_WR_RDMA_READ:
 397                         /*
 398                          * Don't allow more operations to be started
 399                          * than the QP limits allow.
 400                          */
 401                         if (newreq) {
 402                                 if (qp->s_num_rd_atomic >=
 403                                     qp->s_max_rd_atomic) {
 404                                         qp->s_flags |= RVT_S_WAIT_RDMAR;
 405                                         goto bail;
 406                                 }
 407                                 qp->s_num_rd_atomic++;
 408                                 if (!(qp->s_flags & RVT_S_UNLIMITED_CREDIT))
 409                                         qp->s_lsn++;
 410                         }
 411
 412                         ohdr->u.rc.reth.vaddr =
 413                                 cpu_to_be64(wqe->rdma_wr.remote_addr);
 414                         ohdr->u.rc.reth.rkey =
 415                                 cpu_to_be32(wqe->rdma_wr.rkey);
 416                         ohdr->u.rc.reth.length = cpu_to_be32(len);
 417                         qp->s_state = OP(RDMA_READ_REQUEST);
 418                         hwords += sizeof(ohdr->u.rc.reth) / sizeof(u32);
 419                         ss = NULL;
 420                         len = 0;
 421                         bth2 |= IB_BTH_REQ_ACK;
 422                         if (++qp->s_cur == qp->s_size)
 423                                 qp->s_cur = 0;
 424                         break;
 425
 426                 case IB_WR_ATOMIC_CMP_AND_SWP:
 427                 case IB_WR_ATOMIC_FETCH_AND_ADD:
 428                         /*
 429                          * Don't allow more operations to be started
 430                          * than the QP limits allow.
 431                          */
 432                         if (newreq) {
 433                                 if (qp->s_num_rd_atomic >=
 434                                     qp->s_max_rd_atomic) {
 435                                         qp->s_flags |= RVT_S_WAIT_RDMAR;
 436                                         goto bail;
 437                                 }
 438                                 qp->s_num_rd_atomic++;
 439                                 if (!(qp->s_flags & RVT_S_UNLIMITED_CREDIT))
 440                                         qp->s_lsn++;
 441                         }
 442                         if (wqe->atomic_wr.wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP) {
 443                                 qp->s_state = OP(COMPARE_SWAP);
 444                                 put_ib_ateth_swap(wqe->atomic_wr.swap,
 445                                                   &ohdr->u.atomic_eth);
 446                                 put_ib_ateth_swap(wqe->atomic_wr.compare_add,
 447                                                   &ohdr->u.atomic_eth);
 448                         } else {
 449                                 qp->s_state = OP(FETCH_ADD);
 450                                 put_ib_ateth_swap(wqe->atomic_wr.compare_add,
 451                                                   &ohdr->u.atomic_eth);
 452                                 put_ib_ateth_swap(0, &ohdr->u.atomic_eth);
 453                         }
 454                         put_ib_ateth_vaddr(wqe->atomic_wr.remote_addr,
 455                                            &ohdr->u.atomic_eth);
 456                         ohdr->u.atomic_eth.rkey = cpu_to_be32(
 457                                 wqe->atomic_wr.rkey);
 458                         hwords += sizeof(struct ib_atomic_eth) / sizeof(u32);
 459                         ss = NULL;
 460                         len = 0;
 461                         bth2 |= IB_BTH_REQ_ACK;
 462                         if (++qp->s_cur == qp->s_size)
 463                                 qp->s_cur = 0;
 464                         break;
 465
 466                 default:
 467                         goto bail;
 468                 }
 469                 qp->s_sge.sge = wqe->sg_list[0];
 470                 qp->s_sge.sg_list = wqe->sg_list + 1;
 471                 qp->s_sge.num_sge = wqe->wr.num_sge;
 472                 qp->s_sge.total_len = wqe->length;
 473                 qp->s_len = wqe->length;
 474                 if (newreq) {
 475                         qp->s_tail++;
 476                         if (qp->s_tail >= qp->s_size)
 477                                 qp->s_tail = 0;
 478                 }
 479                 if (wqe->wr.opcode == IB_WR_RDMA_READ)
 480                         qp->s_psn = wqe->lpsn + 1;
 481                 else
 482                         qp->s_psn++;
 483                 break;
 484
 485         case OP(RDMA_READ_RESPONSE_FIRST):
 486                 /*
 487                  * qp->s_state is normally set to the opcode of the
 488                  * last packet constructed for new requests and therefore
 489                  * is never set to RDMA read response.
 490                  * RDMA_READ_RESPONSE_FIRST is used by the ACK processing
 491                  * thread to indicate a SEND needs to be restarted from an
 492                  * earlier PSN without interferring with the sending thread.
 493                  * See qib_restart_rc().
 494                  */
 495                 qp->s_len = restart_sge(&qp->s_sge, wqe, qp->s_psn, pmtu);
 496                 /* FALLTHROUGH */
 497         case OP(SEND_FIRST):
 498                 qp->s_state = OP(SEND_MIDDLE);
 499                 /* FALLTHROUGH */
 500         case OP(SEND_MIDDLE):
 501                 bth2 = qp->s_psn++ & QIB_PSN_MASK;
 502                 ss = &qp->s_sge;
 503                 len = qp->s_len;
 504                 if (len > pmtu) {
 505                         len = pmtu;
 506                         break;
 507                 }
 508                 if (wqe->wr.opcode == IB_WR_SEND)
 509                         qp->s_state = OP(SEND_LAST);
 510                 else {
 511                         qp->s_state = OP(SEND_LAST_WITH_IMMEDIATE);
 512                         /* Immediate data comes after the BTH */
 513                         ohdr->u.imm_data = wqe->wr.ex.imm_data;
 514                         hwords += 1;
 515                 }
 516                 if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 517                         bth0 |= IB_BTH_SOLICITED;
 518                 bth2 |= IB_BTH_REQ_ACK;
 519                 qp->s_cur++;
 520                 if (qp->s_cur >= qp->s_size)
 521                         qp->s_cur = 0;
 522                 break;
 523
 524         case OP(RDMA_READ_RESPONSE_LAST):
 525                 /*
 526                  * qp->s_state is normally set to the opcode of the
 527                  * last packet constructed for new requests and therefore
 528                  * is never set to RDMA read response.
 529                  * RDMA_READ_RESPONSE_LAST is used by the ACK processing
 530                  * thread to indicate a RDMA write needs to be restarted from
 531                  * an earlier PSN without interferring with the sending thread.
 532                  * See qib_restart_rc().
 533                  */
 534                 qp->s_len = restart_sge(&qp->s_sge, wqe, qp->s_psn, pmtu);
 535                 /* FALLTHROUGH */
 536         case OP(RDMA_WRITE_FIRST):
 537                 qp->s_state = OP(RDMA_WRITE_MIDDLE);
 538                 /* FALLTHROUGH */
 539         case OP(RDMA_WRITE_MIDDLE):
 540                 bth2 = qp->s_psn++ & QIB_PSN_MASK;
 541                 ss = &qp->s_sge;
 542                 len = qp->s_len;
 543                 if (len > pmtu) {
 544                         len = pmtu;
 545                         break;
 546                 }
 547                 if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
 548                         qp->s_state = OP(RDMA_WRITE_LAST);
 549                 else {
 550                         qp->s_state = OP(RDMA_WRITE_LAST_WITH_IMMEDIATE);
 551                         /* Immediate data comes after the BTH */
 552                         ohdr->u.imm_data = wqe->wr.ex.imm_data;
 553                         hwords += 1;
 554                         if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 555                                 bth0 |= IB_BTH_SOLICITED;
 556                 }
 557                 bth2 |= IB_BTH_REQ_ACK;
 558                 qp->s_cur++;
 559                 if (qp->s_cur >= qp->s_size)
 560                         qp->s_cur = 0;
 561                 break;
 562
 563         case OP(RDMA_READ_RESPONSE_MIDDLE):
 564                 /*
 565                  * qp->s_state is normally set to the opcode of the
 566                  * last packet constructed for new requests and therefore
 567                  * is never set to RDMA read response.
 568                  * RDMA_READ_RESPONSE_MIDDLE is used by the ACK processing
 569                  * thread to indicate a RDMA read needs to be restarted from
 570                  * an earlier PSN without interferring with the sending thread.
 571                  * See qib_restart_rc().
 572                  */
 573                 len = ((qp->s_psn - wqe->psn) & QIB_PSN_MASK) * pmtu;
 574                 ohdr->u.rc.reth.vaddr =
 575                         cpu_to_be64(wqe->rdma_wr.remote_addr + len);
 576                 ohdr->u.rc.reth.rkey =
 577                         cpu_to_be32(wqe->rdma_wr.rkey);
 578                 ohdr->u.rc.reth.length = cpu_to_be32(wqe->length - len);
 579                 qp->s_state = OP(RDMA_READ_REQUEST);
 580                 hwords += sizeof(ohdr->u.rc.reth) / sizeof(u32);
 581                 bth2 = (qp->s_psn & QIB_PSN_MASK) | IB_BTH_REQ_ACK;
 582                 qp->s_psn = wqe->lpsn + 1;
 583                 ss = NULL;
 584                 len = 0;
 585                 qp->s_cur++;
 586                 if (qp->s_cur == qp->s_size)
 587                         qp->s_cur = 0;
 588                 break;
 589         }
 590         qp->s_sending_hpsn = bth2;
 591         delta = (((int) bth2 - (int) wqe->psn) << 8) >> 8;
 592         if (delta && delta % QIB_PSN_CREDIT == 0)
 593                 bth2 |= IB_BTH_REQ_ACK;
 594         if (qp->s_flags & RVT_S_SEND_ONE) {
 595                 qp->s_flags &= ~RVT_S_SEND_ONE;
 596                 qp->s_flags |= RVT_S_WAIT_ACK;
 597                 bth2 |= IB_BTH_REQ_ACK;
 598         }
 599         qp->s_len -= len;
 600         qp->s_hdrwords = hwords;
 601         qp->s_cur_sge = ss;
 602         qp->s_cur_size = len;
 603         qib_make_ruc_header(qp, ohdr, bth0 | (qp->s_state << 24), bth2);
 604 done:
 605         return 1;
 606 bail:
 607         qp->s_flags &= ~RVT_S_BUSY;
 608         return ret;
 609 }
 610
 611 /**
 612  * qib_send_rc_ack - Construct an ACK packet and send it
 613  * @qp: a pointer to the QP
 614  *
 615  * This is called from qib_rc_rcv() and qib_kreceive().
 616  * Note that RDMA reads and atomics are handled in the
 617  * send side QP state and tasklet.
 618  */
 619 void qib_send_rc_ack(struct rvt_qp *qp)
 620 {
 621         struct qib_devdata *dd = dd_from_ibdev(qp->ibqp.device);
 622         struct qib_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
 623         struct qib_pportdata *ppd = ppd_from_ibp(ibp);
 624         u64 pbc;
 625         u16 lrh0;
 626         u32 bth0;
 627         u32 hwords;
 628         u32 pbufn;
 629         u32 __iomem *piobuf;
 630         struct ib_header hdr;
 631         struct ib_other_headers *ohdr;
 632         u32 control;
 633         unsigned long flags;
 634
 635         spin_lock_irqsave(&qp->s_lock, flags);
 636
 637         if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK))
 638                 goto unlock;
 639
 640         /* Don't send ACK or NAK if a RDMA read or atomic is pending. */
 641         if ((qp->s_flags & RVT_S_RESP_PENDING) || qp->s_rdma_ack_cnt)
 642                 goto queue_ack;
 643
 644         /* Construct the header with s_lock held so APM doesn't change it. */
 645         ohdr = &hdr.u.oth;
 646         lrh0 = QIB_LRH_BTH;
 647         /* header size in 32-bit words LRH+BTH+AETH = (8+12+4)/4. */
 648         hwords = 6;
 649         if (unlikely(qp->remote_ah_attr.ah_flags & IB_AH_GRH)) {
 650                 hwords += qib_make_grh(ibp, &hdr.u.l.grh,
 651                                        &qp->remote_ah_attr.grh, hwords, 0);
 652                 ohdr = &hdr.u.l.oth;
 653                 lrh0 = QIB_LRH_GRH;
 654         }
 655         /* read pkey_index w/o lock (its atomic) */
 656         bth0 = qib_get_pkey(ibp, qp->s_pkey_index) | (OP(ACKNOWLEDGE) << 24);
 657         if (qp->s_mig_state == IB_MIG_MIGRATED)
 658                 bth0 |= IB_BTH_MIG_REQ;
 659         if (qp->r_nak_state)
 660                 ohdr->u.aeth = cpu_to_be32((qp->r_msn & QIB_MSN_MASK) |
 661                                             (qp->r_nak_state <<
 662                                              QIB_AETH_CREDIT_SHIFT));
 663         else
 664                 ohdr->u.aeth = qib_compute_aeth(qp);
 665         lrh0 |= ibp->sl_to_vl[qp->remote_ah_attr.sl] << 12 |
 666                 qp->remote_ah_attr.sl << 4;
 667         hdr.lrh[0] = cpu_to_be16(lrh0);
 668         hdr.lrh[1] = cpu_to_be16(qp->remote_ah_attr.dlid);
 669         hdr.lrh[2] = cpu_to_be16(hwords + SIZE_OF_CRC);
 670         hdr.lrh[3] = cpu_to_be16(ppd->lid | qp->remote_ah_attr.src_path_bits);
 671         ohdr->bth[0] = cpu_to_be32(bth0);
 672         ohdr->bth[1] = cpu_to_be32(qp->remote_qpn);
 673         ohdr->bth[2] = cpu_to_be32(qp->r_ack_psn & QIB_PSN_MASK);
 674
 675         spin_unlock_irqrestore(&qp->s_lock, flags);
 676
 677         /* Don't try to send ACKs if the link isn't ACTIVE */
 678         if (!(ppd->lflags & QIBL_LINKACTIVE))
 679                 goto done;
 680
 681         control = dd->f_setpbc_control(ppd, hwords + SIZE_OF_CRC,
 682                                        qp->s_srate, lrh0 >> 12);
 683         /* length is + 1 for the control dword */
 684         pbc = ((u64) control << 32) | (hwords + 1);
 685
 686         piobuf = dd->f_getsendbuf(ppd, pbc, &pbufn);
 687         if (!piobuf) {
 688                 /*
 689                  * We are out of PIO buffers at the moment.
 690                  * Pass responsibility for sending the ACK to the
 691                  * send tasklet so that when a PIO buffer becomes
 692                  * available, the ACK is sent ahead of other outgoing
 693                  * packets.
 694                  */
 695                 spin_lock_irqsave(&qp->s_lock, flags);
 696                 goto queue_ack;
 697         }
 698
 699         /*
 700          * Write the pbc.
 701          * We have to flush after the PBC for correctness
 702          * on some cpus or WC buffer can be written out of order.
 703          */
 704         writeq(pbc, piobuf);
 705
 706         if (dd->flags & QIB_PIO_FLUSH_WC) {
 707                 u32 *hdrp = (u32 *) &hdr;
 708
 709                 qib_flush_wc();
 710                 qib_pio_copy(piobuf + 2, hdrp, hwords - 1);
 711                 qib_flush_wc();
 712                 __raw_writel(hdrp[hwords - 1], piobuf + hwords + 1);
 713         } else
 714                 qib_pio_copy(piobuf + 2, (u32 *) &hdr, hwords);
 715
 716         if (dd->flags & QIB_USE_SPCL_TRIG) {
 717                 u32 spcl_off = (pbufn >= dd->piobcnt2k) ? 2047 : 1023;
 718
 719                 qib_flush_wc();
 720                 __raw_writel(0xaebecede, piobuf + spcl_off);
 721         }
 722
 723         qib_flush_wc();
 724         qib_sendbuf_done(dd, pbufn);
 725
 726         this_cpu_inc(ibp->pmastats->n_unicast_xmit);
 727         goto done;
 728
 729 queue_ack:
 730         if (ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK) {
 731                 this_cpu_inc(*ibp->rvp.rc_qacks);
 732                 qp->s_flags |= RVT_S_ACK_PENDING | RVT_S_RESP_PENDING;
 733                 qp->s_nak_state = qp->r_nak_state;
 734                 qp->s_ack_psn = qp->r_ack_psn;
 735
 736                 /* Schedule the send tasklet. */
 737                 qib_schedule_send(qp);
 738         }
 739 unlock:
 740         spin_unlock_irqrestore(&qp->s_lock, flags);
 741 done:
 742         return;
 743 }
 744
 745 /**
 746  * reset_psn - reset the QP state to send starting from PSN
 747  * @qp: the QP
 748  * @psn: the packet sequence number to restart at
 749  *
 750  * This is called from qib_rc_rcv() to process an incoming RC ACK
 751  * for the given QP.
 752  * Called at interrupt level with the QP s_lock held.
 753  */
 754 static void reset_psn(struct rvt_qp *qp, u32 psn)
 755 {
 756         u32 n = qp->s_acked;
 757         struct rvt_swqe *wqe = rvt_get_swqe_ptr(qp, n);
 758         u32 opcode;
 759
 760         qp->s_cur = n;
 761
 762         /*
 763          * If we are starting the request from the beginning,
 764          * let the normal send code handle initialization.
 765          */
 766         if (qib_cmp24(psn, wqe->psn) <= 0) {
 767                 qp->s_state = OP(SEND_LAST);
 768                 goto done;
 769         }
 770
 771         /* Find the work request opcode corresponding to the given PSN. */
 772         opcode = wqe->wr.opcode;
 773         for (;;) {
 774                 int diff;
 775
 776                 if (++n == qp->s_size)
 777                         n = 0;
 778                 if (n == qp->s_tail)
 779                         break;
 780                 wqe = rvt_get_swqe_ptr(qp, n);
 781                 diff = qib_cmp24(psn, wqe->psn);
 782                 if (diff < 0)
 783                         break;
 784                 qp->s_cur = n;
 785                 /*
 786                  * If we are starting the request from the beginning,
 787                  * let the normal send code handle initialization.
 788                  */
 789                 if (diff == 0) {
 790                         qp->s_state = OP(SEND_LAST);
 791                         goto done;
 792                 }
 793                 opcode = wqe->wr.opcode;
 794         }
 795
 796         /*
 797          * Set the state to restart in the middle of a request.
 798          * Don't change the s_sge, s_cur_sge, or s_cur_size.
 799          * See qib_make_rc_req().
 800          */
 801         switch (opcode) {
 802         case IB_WR_SEND:
 803         case IB_WR_SEND_WITH_IMM:
 804                 qp->s_state = OP(RDMA_READ_RESPONSE_FIRST);
 805                 break;
 806
 807         case IB_WR_RDMA_WRITE:
 808         case IB_WR_RDMA_WRITE_WITH_IMM:
 809                 qp->s_state = OP(RDMA_READ_RESPONSE_LAST);
 810                 break;
 811
 812         case IB_WR_RDMA_READ:
 813                 qp->s_state = OP(RDMA_READ_RESPONSE_MIDDLE);
 814                 break;
 815
 816         default:
 817                 /*
 818                  * This case shouldn't happen since its only
 819                  * one PSN per req.
 820                  */
 821                 qp->s_state = OP(SEND_LAST);
 822         }
 823 done:
 824         qp->s_psn = psn;
 825         /*
 826          * Set RVT_S_WAIT_PSN as qib_rc_complete() may start the timer
 827          * asynchronously before the send tasklet can get scheduled.
 828          * Doing it in qib_make_rc_req() is too late.
 829          */
 830         if ((qib_cmp24(qp->s_psn, qp->s_sending_hpsn) <= 0) &&
 831             (qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) <= 0))
 832                 qp->s_flags |= RVT_S_WAIT_PSN;
 833 }
 834
 835 /*
 836  * Back up requester to resend the last un-ACKed request.
 837  * The QP r_lock and s_lock should be held and interrupts disabled.
 838  */
 839 static void qib_restart_rc(struct rvt_qp *qp, u32 psn, int wait)
 840 {
 841         struct rvt_swqe *wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
 842         struct qib_ibport *ibp;
 843
 844         if (qp->s_retry == 0) {
 845                 if (qp->s_mig_state == IB_MIG_ARMED) {
 846                         qib_migrate_qp(qp);
 847                         qp->s_retry = qp->s_retry_cnt;
 848                 } else if (qp->s_last == qp->s_acked) {
 849                         qib_send_complete(qp, wqe, IB_WC_RETRY_EXC_ERR);
 850                         rvt_error_qp(qp, IB_WC_WR_FLUSH_ERR);
 851                         return;
 852                 } else /* XXX need to handle delayed completion */
 853                         return;
 854         } else
 855                 qp->s_retry--;
 856
 857         ibp = to_iport(qp->ibqp.device, qp->port_num);
 858         if (wqe->wr.opcode == IB_WR_RDMA_READ)
 859                 ibp->rvp.n_rc_resends++;
 860         else
 861                 ibp->rvp.n_rc_resends += (qp->s_psn - psn) & QIB_PSN_MASK;
 862
 863         qp->s_flags &= ~(RVT_S_WAIT_FENCE | RVT_S_WAIT_RDMAR |
 864                          RVT_S_WAIT_SSN_CREDIT | RVT_S_WAIT_PSN |
 865                          RVT_S_WAIT_ACK);
 866         if (wait)
 867                 qp->s_flags |= RVT_S_SEND_ONE;
 868         reset_psn(qp, psn);
 869 }
 870
 871 /*
 872  * This is called from s_timer for missing responses.
 873  */
 874 static void rc_timeout(unsigned long arg)
 875 {
 876         struct rvt_qp *qp = (struct rvt_qp *)arg;
 877         struct qib_ibport *ibp;
 878         unsigned long flags;
 879
 880         spin_lock_irqsave(&qp->r_lock, flags);
 881         spin_lock(&qp->s_lock);
 882         if (qp->s_flags & RVT_S_TIMER) {
 883                 ibp = to_iport(qp->ibqp.device, qp->port_num);
 884                 ibp->rvp.n_rc_timeouts++;
 885                 qp->s_flags &= ~RVT_S_TIMER;
 886                 del_timer(&qp->s_timer);
 887                 qib_restart_rc(qp, qp->s_last_psn + 1, 1);
 888                 qib_schedule_send(qp);
 889         }
 890         spin_unlock(&qp->s_lock);
 891         spin_unlock_irqrestore(&qp->r_lock, flags);
 892 }
 893
 894 /*
 895  * This is called from s_timer for RNR timeouts.
 896  */
 897 void qib_rc_rnr_retry(unsigned long arg)
 898 {
 899         struct rvt_qp *qp = (struct rvt_qp *)arg;
 900         unsigned long flags;
 901
 902         spin_lock_irqsave(&qp->s_lock, flags);
 903         if (qp->s_flags & RVT_S_WAIT_RNR) {
 904                 qp->s_flags &= ~RVT_S_WAIT_RNR;
 905                 del_timer(&qp->s_timer);
 906                 qib_schedule_send(qp);
 907         }
 908         spin_unlock_irqrestore(&qp->s_lock, flags);
 909 }
 910
 911 /*
 912  * Set qp->s_sending_psn to the next PSN after the given one.
 913  * This would be psn+1 except when RDMA reads are present.
 914  */
 915 static void reset_sending_psn(struct rvt_qp *qp, u32 psn)
 916 {
 917         struct rvt_swqe *wqe;
 918         u32 n = qp->s_last;
 919
 920         /* Find the work request corresponding to the given PSN. */
 921         for (;;) {
 922                 wqe = rvt_get_swqe_ptr(qp, n);
 923                 if (qib_cmp24(psn, wqe->lpsn) <= 0) {
 924                         if (wqe->wr.opcode == IB_WR_RDMA_READ)
 925                                 qp->s_sending_psn = wqe->lpsn + 1;
 926                         else
 927                                 qp->s_sending_psn = psn + 1;
 928                         break;
 929                 }
 930                 if (++n == qp->s_size)
 931                         n = 0;
 932                 if (n == qp->s_tail)
 933                         break;
 934         }
 935 }
 936
 937 /*
 938  * This should be called with the QP s_lock held and interrupts disabled.
 939  */
 940 void qib_rc_send_complete(struct rvt_qp *qp, struct ib_header *hdr)
 941 {
 942         struct ib_other_headers *ohdr;
 943         struct rvt_swqe *wqe;
 944         struct ib_wc wc;
 945         unsigned i;
 946         u32 opcode;
 947         u32 psn;
 948
 949         if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_OR_FLUSH_SEND))
 950                 return;
 951
 952         /* Find out where the BTH is */
 953         if ((be16_to_cpu(hdr->lrh[0]) & 3) == QIB_LRH_BTH)
 954                 ohdr = &hdr->u.oth;
 955         else
 956                 ohdr = &hdr->u.l.oth;
 957
 958         opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
 959         if (opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
 960             opcode <= OP(ATOMIC_ACKNOWLEDGE)) {
 961                 WARN_ON(!qp->s_rdma_ack_cnt);
 962                 qp->s_rdma_ack_cnt--;
 963                 return;
 964         }
 965
 966         psn = be32_to_cpu(ohdr->bth[2]);
 967         reset_sending_psn(qp, psn);
 968
 969         /*
 970          * Start timer after a packet requesting an ACK has been sent and
 971          * there are still requests that haven't been acked.
 972          */
 973         if ((psn & IB_BTH_REQ_ACK) && qp->s_acked != qp->s_tail &&
 974             !(qp->s_flags & (RVT_S_TIMER | RVT_S_WAIT_RNR | RVT_S_WAIT_PSN)) &&
 975             (ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK))
 976                 start_timer(qp);
 977
 978         while (qp->s_last != qp->s_acked) {
 979                 u32 s_last;
 980
 981                 wqe = rvt_get_swqe_ptr(qp, qp->s_last);
 982                 if (qib_cmp24(wqe->lpsn, qp->s_sending_psn) >= 0 &&
 983                     qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) <= 0)
 984                         break;
 985                 s_last = qp->s_last;
 986                 if (++s_last >= qp->s_size)
 987                         s_last = 0;
 988                 qp->s_last = s_last;
 989                 /* see post_send() */
 990                 barrier();
 991                 for (i = 0; i < wqe->wr.num_sge; i++) {
 992                         struct rvt_sge *sge = &wqe->sg_list[i];
 993
 994                         rvt_put_mr(sge->mr);
 995                 }
 996                 /* Post a send completion queue entry if requested. */
 997                 if (!(qp->s_flags & RVT_S_SIGNAL_REQ_WR) ||
 998                     (wqe->wr.send_flags & IB_SEND_SIGNALED)) {
 999                         memset(&wc, 0, sizeof(wc));
1000                         wc.wr_id = wqe->wr.wr_id;
1001                         wc.status = IB_WC_SUCCESS;
1002                         wc.opcode = ib_qib_wc_opcode[wqe->wr.opcode];
1003                         wc.byte_len = wqe->length;
1004                         wc.qp = &qp->ibqp;
1005                         rvt_cq_enter(ibcq_to_rvtcq(qp->ibqp.send_cq), &wc, 0);
1006                 }
1007         }
1008         /*
1009          * If we were waiting for sends to complete before resending,
1010          * and they are now complete, restart sending.
1011          */
1012         if (qp->s_flags & RVT_S_WAIT_PSN &&
1013             qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) > 0) {
1014                 qp->s_flags &= ~RVT_S_WAIT_PSN;
1015                 qp->s_sending_psn = qp->s_psn;
1016                 qp->s_sending_hpsn = qp->s_psn - 1;
1017                 qib_schedule_send(qp);
1018         }
1019 }
1020
1021 static inline void update_last_psn(struct rvt_qp *qp, u32 psn)
1022 {
1023         qp->s_last_psn = psn;
1024 }
1025
1026 /*
1027  * Generate a SWQE completion.
1028  * This is similar to qib_send_complete but has to check to be sure
1029  * that the SGEs are not being referenced if the SWQE is being resent.
1030  */
1031 static struct rvt_swqe *do_rc_completion(struct rvt_qp *qp,
1032                                          struct rvt_swqe *wqe,
1033                                          struct qib_ibport *ibp)
1034 {
1035         struct ib_wc wc;
1036         unsigned i;
1037
1038         /*
1039          * Don't decrement refcount and don't generate a
1040          * completion if the SWQE is being resent until the send
1041          * is finished.
1042          */
1043         if (qib_cmp24(wqe->lpsn, qp->s_sending_psn) < 0 ||
1044             qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) > 0) {
1045                 u32 s_last;
1046
1047                 for (i = 0; i < wqe->wr.num_sge; i++) {
1048                         struct rvt_sge *sge = &wqe->sg_list[i];
1049
1050                         rvt_put_mr(sge->mr);
1051                 }
1052                 s_last = qp->s_last;
1053                 if (++s_last >= qp->s_size)
1054                         s_last = 0;
1055                 qp->s_last = s_last;
1056                 /* see post_send() */
1057                 barrier();
1058                 /* Post a send completion queue entry if requested. */
1059                 if (!(qp->s_flags & RVT_S_SIGNAL_REQ_WR) ||
1060                     (wqe->wr.send_flags & IB_SEND_SIGNALED)) {
1061                         memset(&wc, 0, sizeof(wc));
1062                         wc.wr_id = wqe->wr.wr_id;
1063                         wc.status = IB_WC_SUCCESS;
1064                         wc.opcode = ib_qib_wc_opcode[wqe->wr.opcode];
1065                         wc.byte_len = wqe->length;
1066                         wc.qp = &qp->ibqp;
1067                         rvt_cq_enter(ibcq_to_rvtcq(qp->ibqp.send_cq), &wc, 0);
1068                 }
1069         } else
1070                 this_cpu_inc(*ibp->rvp.rc_delayed_comp);
1071
1072         qp->s_retry = qp->s_retry_cnt;
1073         update_last_psn(qp, wqe->lpsn);
1074
1075         /*
1076          * If we are completing a request which is in the process of
1077          * being resent, we can stop resending it since we know the
1078          * responder has already seen it.
1079          */
1080         if (qp->s_acked == qp->s_cur) {
1081                 if (++qp->s_cur >= qp->s_size)
1082                         qp->s_cur = 0;
1083                 qp->s_acked = qp->s_cur;
1084                 wqe = rvt_get_swqe_ptr(qp, qp->s_cur);
1085                 if (qp->s_acked != qp->s_tail) {
1086                         qp->s_state = OP(SEND_LAST);
1087                         qp->s_psn = wqe->psn;
1088                 }
1089         } else {
1090                 if (++qp->s_acked >= qp->s_size)
1091                         qp->s_acked = 0;
1092                 if (qp->state == IB_QPS_SQD && qp->s_acked == qp->s_cur)
1093                         qp->s_draining = 0;
1094                 wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1095         }
1096         return wqe;
1097 }
1098
1099 /**
1100  * do_rc_ack - process an incoming RC ACK
1101  * @qp: the QP the ACK came in on
1102  * @psn: the packet sequence number of the ACK
1103  * @opcode: the opcode of the request that resulted in the ACK
1104  *
1105  * This is called from qib_rc_rcv_resp() to process an incoming RC ACK
1106  * for the given QP.
1107  * Called at interrupt level with the QP s_lock held.
1108  * Returns 1 if OK, 0 if current operation should be aborted (NAK).
1109  */
1110 static int do_rc_ack(struct rvt_qp *qp, u32 aeth, u32 psn, int opcode,
1111                      u64 val, struct qib_ctxtdata *rcd)
1112 {
1113         struct qib_ibport *ibp;
1114         enum ib_wc_status status;
1115         struct rvt_swqe *wqe;
1116         int ret = 0;
1117         u32 ack_psn;
1118         int diff;
1119
1120         /* Remove QP from retry timer */
1121         if (qp->s_flags & (RVT_S_TIMER | RVT_S_WAIT_RNR)) {
1122                 qp->s_flags &= ~(RVT_S_TIMER | RVT_S_WAIT_RNR);
1123                 del_timer(&qp->s_timer);
1124         }
1125
1126         /*
1127          * Note that NAKs implicitly ACK outstanding SEND and RDMA write
1128          * requests and implicitly NAK RDMA read and atomic requests issued
1129          * before the NAK'ed request.  The MSN won't include the NAK'ed
1130          * request but will include an ACK'ed request(s).
1131          */
1132         ack_psn = psn;
1133         if (aeth >> 29)
1134                 ack_psn--;
1135         wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1136         ibp = to_iport(qp->ibqp.device, qp->port_num);
1137
1138         /*
1139          * The MSN might be for a later WQE than the PSN indicates so
1140          * only complete WQEs that the PSN finishes.
1141          */
1142         while ((diff = qib_cmp24(ack_psn, wqe->lpsn)) >= 0) {
1143                 /*
1144                  * RDMA_READ_RESPONSE_ONLY is a special case since
1145                  * we want to generate completion events for everything
1146                  * before the RDMA read, copy the data, then generate
1147                  * the completion for the read.
1148                  */
1149                 if (wqe->wr.opcode == IB_WR_RDMA_READ &&
1150                     opcode == OP(RDMA_READ_RESPONSE_ONLY) &&
1151                     diff == 0) {
1152                         ret = 1;
1153                         goto bail;
1154                 }
1155                 /*
1156                  * If this request is a RDMA read or atomic, and the ACK is
1157                  * for a later operation, this ACK NAKs the RDMA read or
1158                  * atomic.  In other words, only a RDMA_READ_LAST or ONLY
1159                  * can ACK a RDMA read and likewise for atomic ops.  Note
1160                  * that the NAK case can only happen if relaxed ordering is
1161                  * used and requests are sent after an RDMA read or atomic
1162                  * is sent but before the response is received.
1163                  */
1164                 if ((wqe->wr.opcode == IB_WR_RDMA_READ &&
1165                      (opcode != OP(RDMA_READ_RESPONSE_LAST) || diff != 0)) ||
1166                     ((wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1167                       wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) &&
1168                      (opcode != OP(ATOMIC_ACKNOWLEDGE) || diff != 0))) {
1169                         /* Retry this request. */
1170                         if (!(qp->r_flags & RVT_R_RDMAR_SEQ)) {
1171                                 qp->r_flags |= RVT_R_RDMAR_SEQ;
1172                                 qib_restart_rc(qp, qp->s_last_psn + 1, 0);
1173                                 if (list_empty(&qp->rspwait)) {
1174                                         qp->r_flags |= RVT_R_RSP_SEND;
1175                                         rvt_get_qp(qp);
1176                                         list_add_tail(&qp->rspwait,
1177                                                       &rcd->qp_wait_list);
1178                                 }
1179                         }
1180                         /*
1181                          * No need to process the ACK/NAK since we are
1182                          * restarting an earlier request.
1183                          */
1184                         goto bail;
1185                 }
1186                 if (wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1187                     wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) {
1188                         u64 *vaddr = wqe->sg_list[0].vaddr;
1189                         *vaddr = val;
1190                 }
1191                 if (qp->s_num_rd_atomic &&
1192                     (wqe->wr.opcode == IB_WR_RDMA_READ ||
1193                      wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1194                      wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)) {
1195                         qp->s_num_rd_atomic--;
1196                         /* Restart sending task if fence is complete */
1197                         if ((qp->s_flags & RVT_S_WAIT_FENCE) &&
1198                             !qp->s_num_rd_atomic) {
1199                                 qp->s_flags &= ~(RVT_S_WAIT_FENCE |
1200                                                  RVT_S_WAIT_ACK);
1201                                 qib_schedule_send(qp);
1202                         } else if (qp->s_flags & RVT_S_WAIT_RDMAR) {
1203                                 qp->s_flags &= ~(RVT_S_WAIT_RDMAR |
1204                                                  RVT_S_WAIT_ACK);
1205                                 qib_schedule_send(qp);
1206                         }
1207                 }
1208                 wqe = do_rc_completion(qp, wqe, ibp);
1209                 if (qp->s_acked == qp->s_tail)
1210                         break;
1211         }
1212
1213         switch (aeth >> 29) {
1214         case 0:         /* ACK */
1215                 this_cpu_inc(*ibp->rvp.rc_acks);
1216                 if (qp->s_acked != qp->s_tail) {
1217                         /*
1218                          * We are expecting more ACKs so
1219                          * reset the retransmit timer.
1220                          */
1221                         start_timer(qp);
1222                         /*
1223                          * We can stop resending the earlier packets and
1224                          * continue with the next packet the receiver wants.
1225                          */
1226                         if (qib_cmp24(qp->s_psn, psn) <= 0)
1227                                 reset_psn(qp, psn + 1);
1228                 } else if (qib_cmp24(qp->s_psn, psn) <= 0) {
1229                         qp->s_state = OP(SEND_LAST);
1230                         qp->s_psn = psn + 1;
1231                 }
1232                 if (qp->s_flags & RVT_S_WAIT_ACK) {
1233                         qp->s_flags &= ~RVT_S_WAIT_ACK;
1234                         qib_schedule_send(qp);
1235                 }
1236                 qib_get_credit(qp, aeth);
1237                 qp->s_rnr_retry = qp->s_rnr_retry_cnt;
1238                 qp->s_retry = qp->s_retry_cnt;
1239                 update_last_psn(qp, psn);
1240                 ret = 1;
1241                 goto bail;
1242
1243         case 1:         /* RNR NAK */
1244                 ibp->rvp.n_rnr_naks++;
1245                 if (qp->s_acked == qp->s_tail)
1246                         goto bail;
1247                 if (qp->s_flags & RVT_S_WAIT_RNR)
1248                         goto bail;
1249                 if (qp->s_rnr_retry == 0) {
1250                         status = IB_WC_RNR_RETRY_EXC_ERR;
1251                         goto class_b;
1252                 }
1253                 if (qp->s_rnr_retry_cnt < 7)
1254                         qp->s_rnr_retry--;
1255
1256                 /* The last valid PSN is the previous PSN. */
1257                 update_last_psn(qp, psn - 1);
1258
1259                 ibp->rvp.n_rc_resends += (qp->s_psn - psn) & QIB_PSN_MASK;
1260
1261                 reset_psn(qp, psn);
1262
1263                 qp->s_flags &= ~(RVT_S_WAIT_SSN_CREDIT | RVT_S_WAIT_ACK);
1264                 qp->s_flags |= RVT_S_WAIT_RNR;
1265                 qp->s_timer.function = qib_rc_rnr_retry;
1266                 qp->s_timer.expires = jiffies + usecs_to_jiffies(
1267                         ib_qib_rnr_table[(aeth >> QIB_AETH_CREDIT_SHIFT) &
1268                                            QIB_AETH_CREDIT_MASK]);
1269                 add_timer(&qp->s_timer);
1270                 goto bail;
1271
1272         case 3:         /* NAK */
1273                 if (qp->s_acked == qp->s_tail)
1274                         goto bail;
1275                 /* The last valid PSN is the previous PSN. */
1276                 update_last_psn(qp, psn - 1);
1277                 switch ((aeth >> QIB_AETH_CREDIT_SHIFT) &
1278                         QIB_AETH_CREDIT_MASK) {
1279                 case 0: /* PSN sequence error */
1280                         ibp->rvp.n_seq_naks++;
1281                         /*
1282                          * Back up to the responder's expected PSN.
1283                          * Note that we might get a NAK in the middle of an
1284                          * RDMA READ response which terminates the RDMA
1285                          * READ.
1286                          */
1287                         qib_restart_rc(qp, psn, 0);
1288                         qib_schedule_send(qp);
1289                         break;
1290
1291                 case 1: /* Invalid Request */
1292                         status = IB_WC_REM_INV_REQ_ERR;
1293                         ibp->rvp.n_other_naks++;
1294                         goto class_b;
1295
1296                 case 2: /* Remote Access Error */
1297                         status = IB_WC_REM_ACCESS_ERR;
1298                         ibp->rvp.n_other_naks++;
1299                         goto class_b;
1300
1301                 case 3: /* Remote Operation Error */
1302                         status = IB_WC_REM_OP_ERR;
1303                         ibp->rvp.n_other_naks++;
1304 class_b:
1305                         if (qp->s_last == qp->s_acked) {
1306                                 qib_send_complete(qp, wqe, status);
1307                                 rvt_error_qp(qp, IB_WC_WR_FLUSH_ERR);
1308                         }
1309                         break;
1310
1311                 default:
1312                         /* Ignore other reserved NAK error codes */
1313                         goto reserved;
1314                 }
1315                 qp->s_retry = qp->s_retry_cnt;
1316                 qp->s_rnr_retry = qp->s_rnr_retry_cnt;
1317                 goto bail;
1318
1319         default:                /* 2: reserved */
1320 reserved:
1321                 /* Ignore reserved NAK codes. */
1322                 goto bail;
1323         }
1324
1325 bail:
1326         return ret;
1327 }
1328
1329 /*
1330  * We have seen an out of sequence RDMA read middle or last packet.
1331  * This ACKs SENDs and RDMA writes up to the first RDMA read or atomic SWQE.
1332  */
1333 static void rdma_seq_err(struct rvt_qp *qp, struct qib_ibport *ibp, u32 psn,
1334                          struct qib_ctxtdata *rcd)
1335 {
1336         struct rvt_swqe *wqe;
1337
1338         /* Remove QP from retry timer */
1339         if (qp->s_flags & (RVT_S_TIMER | RVT_S_WAIT_RNR)) {
1340                 qp->s_flags &= ~(RVT_S_TIMER | RVT_S_WAIT_RNR);
1341                 del_timer(&qp->s_timer);
1342         }
1343
1344         wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1345
1346         while (qib_cmp24(psn, wqe->lpsn) > 0) {
1347                 if (wqe->wr.opcode == IB_WR_RDMA_READ ||
1348                     wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1349                     wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)
1350                         break;
1351                 wqe = do_rc_completion(qp, wqe, ibp);
1352         }
1353
1354         ibp->rvp.n_rdma_seq++;
1355         qp->r_flags |= RVT_R_RDMAR_SEQ;
1356         qib_restart_rc(qp, qp->s_last_psn + 1, 0);
1357         if (list_empty(&qp->rspwait)) {
1358                 qp->r_flags |= RVT_R_RSP_SEND;
1359                 rvt_get_qp(qp);
1360                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
1361         }
1362 }
1363
1364 /**
1365  * qib_rc_rcv_resp - process an incoming RC response packet
1366  * @ibp: the port this packet came in on
1367  * @ohdr: the other headers for this packet
1368  * @data: the packet data
1369  * @tlen: the packet length
1370  * @qp: the QP for this packet
1371  * @opcode: the opcode for this packet
1372  * @psn: the packet sequence number for this packet
1373  * @hdrsize: the header length
1374  * @pmtu: the path MTU
1375  *
1376  * This is called from qib_rc_rcv() to process an incoming RC response
1377  * packet for the given QP.
1378  * Called at interrupt level.
1379  */
1380 static void qib_rc_rcv_resp(struct qib_ibport *ibp,
1381                             struct ib_other_headers *ohdr,
1382                             void *data, u32 tlen,
1383                             struct rvt_qp *qp,
1384                             u32 opcode,
1385                             u32 psn, u32 hdrsize, u32 pmtu,
1386                             struct qib_ctxtdata *rcd)
1387 {
1388         struct rvt_swqe *wqe;
1389         struct qib_pportdata *ppd = ppd_from_ibp(ibp);
1390         enum ib_wc_status status;
1391         unsigned long flags;
1392         int diff;
1393         u32 pad;
1394         u32 aeth;
1395         u64 val;
1396
1397         if (opcode != OP(RDMA_READ_RESPONSE_MIDDLE)) {
1398                 /*
1399                  * If ACK'd PSN on SDMA busy list try to make progress to
1400                  * reclaim SDMA credits.
1401                  */
1402                 if ((qib_cmp24(psn, qp->s_sending_psn) >= 0) &&
1403                     (qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) <= 0)) {
1404
1405                         /*
1406                          * If send tasklet not running attempt to progress
1407                          * SDMA queue.
1408                          */
1409                         if (!(qp->s_flags & RVT_S_BUSY)) {
1410                                 /* Acquire SDMA Lock */
1411                                 spin_lock_irqsave(&ppd->sdma_lock, flags);
1412                                 /* Invoke sdma make progress */
1413                                 qib_sdma_make_progress(ppd);
1414                                 /* Release SDMA Lock */
1415                                 spin_unlock_irqrestore(&ppd->sdma_lock, flags);
1416                         }
1417                 }
1418         }
1419
1420         spin_lock_irqsave(&qp->s_lock, flags);
1421         if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK))
1422                 goto ack_done;
1423
1424         /* Ignore invalid responses. */
1425         smp_read_barrier_depends(); /* see post_one_send */
1426         if (qib_cmp24(psn, ACCESS_ONCE(qp->s_next_psn)) >= 0)
1427                 goto ack_done;
1428
1429         /* Ignore duplicate responses. */
1430         diff = qib_cmp24(psn, qp->s_last_psn);
1431         if (unlikely(diff <= 0)) {
1432                 /* Update credits for "ghost" ACKs */
1433                 if (diff == 0 && opcode == OP(ACKNOWLEDGE)) {
1434                         aeth = be32_to_cpu(ohdr->u.aeth);
1435                         if ((aeth >> 29) == 0)
1436                                 qib_get_credit(qp, aeth);
1437                 }
1438                 goto ack_done;
1439         }
1440
1441         /*
1442          * Skip everything other than the PSN we expect, if we are waiting
1443          * for a reply to a restarted RDMA read or atomic op.
1444          */
1445         if (qp->r_flags & RVT_R_RDMAR_SEQ) {
1446                 if (qib_cmp24(psn, qp->s_last_psn + 1) != 0)
1447                         goto ack_done;
1448                 qp->r_flags &= ~RVT_R_RDMAR_SEQ;
1449         }
1450
1451         if (unlikely(qp->s_acked == qp->s_tail))
1452                 goto ack_done;
1453         wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1454         status = IB_WC_SUCCESS;
1455
1456         switch (opcode) {
1457         case OP(ACKNOWLEDGE):
1458         case OP(ATOMIC_ACKNOWLEDGE):
1459         case OP(RDMA_READ_RESPONSE_FIRST):
1460                 aeth = be32_to_cpu(ohdr->u.aeth);
1461                 if (opcode == OP(ATOMIC_ACKNOWLEDGE))
1462                         val = ib_u64_get(&ohdr->u.at.atomic_ack_eth);
1463                 else
1464                         val = 0;
1465                 if (!do_rc_ack(qp, aeth, psn, opcode, val, rcd) ||
1466                     opcode != OP(RDMA_READ_RESPONSE_FIRST))
1467                         goto ack_done;
1468                 hdrsize += 4;
1469                 wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1470                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1471                         goto ack_op_err;
1472                 /*
1473                  * If this is a response to a resent RDMA read, we
1474                  * have to be careful to copy the data to the right
1475                  * location.
1476                  */
1477                 qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
1478                                                   wqe, psn, pmtu);
1479                 goto read_middle;
1480
1481         case OP(RDMA_READ_RESPONSE_MIDDLE):
1482                 /* no AETH, no ACK */
1483                 if (unlikely(qib_cmp24(psn, qp->s_last_psn + 1)))
1484                         goto ack_seq_err;
1485                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1486                         goto ack_op_err;
1487 read_middle:
1488                 if (unlikely(tlen != (hdrsize + pmtu + 4)))
1489                         goto ack_len_err;
1490                 if (unlikely(pmtu >= qp->s_rdma_read_len))
1491                         goto ack_len_err;
1492
1493                 /*
1494                  * We got a response so update the timeout.
1495                  * 4.096 usec. * (1 << qp->timeout)
1496                  */
1497                 qp->s_flags |= RVT_S_TIMER;
1498                 mod_timer(&qp->s_timer, jiffies + qp->timeout_jiffies);
1499                 if (qp->s_flags & RVT_S_WAIT_ACK) {
1500                         qp->s_flags &= ~RVT_S_WAIT_ACK;
1501                         qib_schedule_send(qp);
1502                 }
1503
1504                 if (opcode == OP(RDMA_READ_RESPONSE_MIDDLE))
1505                         qp->s_retry = qp->s_retry_cnt;
1506
1507                 /*
1508                  * Update the RDMA receive state but do the copy w/o
1509                  * holding the locks and blocking interrupts.
1510                  */
1511                 qp->s_rdma_read_len -= pmtu;
1512                 update_last_psn(qp, psn);
1513                 spin_unlock_irqrestore(&qp->s_lock, flags);
1514                 qib_copy_sge(&qp->s_rdma_read_sge, data, pmtu, 0);
1515                 goto bail;
1516
1517         case OP(RDMA_READ_RESPONSE_ONLY):
1518                 aeth = be32_to_cpu(ohdr->u.aeth);
1519                 if (!do_rc_ack(qp, aeth, psn, opcode, 0, rcd))
1520                         goto ack_done;
1521                 /* Get the number of bytes the message was padded by. */
1522                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1523                 /*
1524                  * Check that the data size is >= 0 && <= pmtu.
1525                  * Remember to account for the AETH header (4) and
1526                  * ICRC (4).
1527                  */
1528                 if (unlikely(tlen < (hdrsize + pad + 8)))
1529                         goto ack_len_err;
1530                 /*
1531                  * If this is a response to a resent RDMA read, we
1532                  * have to be careful to copy the data to the right
1533                  * location.
1534                  */
1535                 wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1536                 qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
1537                                                   wqe, psn, pmtu);
1538                 goto read_last;
1539
1540         case OP(RDMA_READ_RESPONSE_LAST):
1541                 /* ACKs READ req. */
1542                 if (unlikely(qib_cmp24(psn, qp->s_last_psn + 1)))
1543                         goto ack_seq_err;
1544                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1545                         goto ack_op_err;
1546                 /* Get the number of bytes the message was padded by. */
1547                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1548                 /*
1549                  * Check that the data size is >= 1 && <= pmtu.
1550                  * Remember to account for the AETH header (4) and
1551                  * ICRC (4).
1552                  */
1553                 if (unlikely(tlen <= (hdrsize + pad + 8)))
1554                         goto ack_len_err;
1555 read_last:
1556                 tlen -= hdrsize + pad + 8;
1557                 if (unlikely(tlen != qp->s_rdma_read_len))
1558                         goto ack_len_err;
1559                 aeth = be32_to_cpu(ohdr->u.aeth);
1560                 qib_copy_sge(&qp->s_rdma_read_sge, data, tlen, 0);
1561                 WARN_ON(qp->s_rdma_read_sge.num_sge);
1562                 (void) do_rc_ack(qp, aeth, psn,
1563                                  OP(RDMA_READ_RESPONSE_LAST), 0, rcd);
1564                 goto ack_done;
1565         }
1566
1567 ack_op_err:
1568         status = IB_WC_LOC_QP_OP_ERR;
1569         goto ack_err;
1570
1571 ack_seq_err:
1572         rdma_seq_err(qp, ibp, psn, rcd);
1573         goto ack_done;
1574
1575 ack_len_err:
1576         status = IB_WC_LOC_LEN_ERR;
1577 ack_err:
1578         if (qp->s_last == qp->s_acked) {
1579                 qib_send_complete(qp, wqe, status);
1580                 rvt_error_qp(qp, IB_WC_WR_FLUSH_ERR);
1581         }
1582 ack_done:
1583         spin_unlock_irqrestore(&qp->s_lock, flags);
1584 bail:
1585         return;
1586 }
1587
1588 /**
1589  * qib_rc_rcv_error - process an incoming duplicate or error RC packet
1590  * @ohdr: the other headers for this packet
1591  * @data: the packet data
1592  * @qp: the QP for this packet
1593  * @opcode: the opcode for this packet
1594  * @psn: the packet sequence number for this packet
1595  * @diff: the difference between the PSN and the expected PSN
1596  *
1597  * This is called from qib_rc_rcv() to process an unexpected
1598  * incoming RC packet for the given QP.
1599  * Called at interrupt level.
1600  * Return 1 if no more processing is needed; otherwise return 0 to
1601  * schedule a response to be sent.
1602  */
1603 static int qib_rc_rcv_error(struct ib_other_headers *ohdr,
1604                             void *data,
1605                             struct rvt_qp *qp,
1606                             u32 opcode,
1607                             u32 psn,
1608                             int diff,
1609                             struct qib_ctxtdata *rcd)
1610 {
1611         struct qib_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
1612         struct rvt_ack_entry *e;
1613         unsigned long flags;
1614         u8 i, prev;
1615         int old_req;
1616
1617         if (diff > 0) {
1618                 /*
1619                  * Packet sequence error.
1620                  * A NAK will ACK earlier sends and RDMA writes.
1621                  * Don't queue the NAK if we already sent one.
1622                  */
1623                 if (!qp->r_nak_state) {
1624                         ibp->rvp.n_rc_seqnak++;
1625                         qp->r_nak_state = IB_NAK_PSN_ERROR;
1626                         /* Use the expected PSN. */
1627                         qp->r_ack_psn = qp->r_psn;
1628                         /*
1629                          * Wait to send the sequence NAK until all packets
1630                          * in the receive queue have been processed.
1631                          * Otherwise, we end up propagating congestion.
1632                          */
1633                         if (list_empty(&qp->rspwait)) {
1634                                 qp->r_flags |= RVT_R_RSP_NAK;
1635                                 rvt_get_qp(qp);
1636                                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
1637                         }
1638                 }
1639                 goto done;
1640         }
1641
1642         /*
1643          * Handle a duplicate request.  Don't re-execute SEND, RDMA
1644          * write or atomic op.  Don't NAK errors, just silently drop
1645          * the duplicate request.  Note that r_sge, r_len, and
1646          * r_rcv_len may be in use so don't modify them.
1647          *
1648          * We are supposed to ACK the earliest duplicate PSN but we
1649          * can coalesce an outstanding duplicate ACK.  We have to
1650          * send the earliest so that RDMA reads can be restarted at
1651          * the requester's expected PSN.
1652          *
1653          * First, find where this duplicate PSN falls within the
1654          * ACKs previously sent.
1655          * old_req is true if there is an older response that is scheduled
1656          * to be sent before sending this one.
1657          */
1658         e = NULL;
1659         old_req = 1;
1660         ibp->rvp.n_rc_dupreq++;
1661
1662         spin_lock_irqsave(&qp->s_lock, flags);
1663
1664         for (i = qp->r_head_ack_queue; ; i = prev) {
1665                 if (i == qp->s_tail_ack_queue)
1666                         old_req = 0;
1667                 if (i)
1668                         prev = i - 1;
1669                 else
1670                         prev = QIB_MAX_RDMA_ATOMIC;
1671                 if (prev == qp->r_head_ack_queue) {
1672                         e = NULL;
1673                         break;
1674                 }
1675                 e = &qp->s_ack_queue[prev];
1676                 if (!e->opcode) {
1677                         e = NULL;
1678                         break;
1679                 }
1680                 if (qib_cmp24(psn, e->psn) >= 0) {
1681                         if (prev == qp->s_tail_ack_queue &&
1682                             qib_cmp24(psn, e->lpsn) <= 0)
1683                                 old_req = 0;
1684                         break;
1685                 }
1686         }
1687         switch (opcode) {
1688         case OP(RDMA_READ_REQUEST): {
1689                 struct ib_reth *reth;
1690                 u32 offset;
1691                 u32 len;
1692
1693                 /*
1694                  * If we didn't find the RDMA read request in the ack queue,
1695                  * we can ignore this request.
1696                  */
1697                 if (!e || e->opcode != OP(RDMA_READ_REQUEST))
1698                         goto unlock_done;
1699                 /* RETH comes after BTH */
1700                 reth = &ohdr->u.rc.reth;
1701                 /*
1702                  * Address range must be a subset of the original
1703                  * request and start on pmtu boundaries.
1704                  * We reuse the old ack_queue slot since the requester
1705                  * should not back up and request an earlier PSN for the
1706                  * same request.
1707                  */
1708                 offset = ((psn - e->psn) & QIB_PSN_MASK) *
1709                         qp->pmtu;
1710                 len = be32_to_cpu(reth->length);
1711                 if (unlikely(offset + len != e->rdma_sge.sge_length))
1712                         goto unlock_done;
1713                 if (e->rdma_sge.mr) {
1714                         rvt_put_mr(e->rdma_sge.mr);
1715                         e->rdma_sge.mr = NULL;
1716                 }
1717                 if (len != 0) {
1718                         u32 rkey = be32_to_cpu(reth->rkey);
1719                         u64 vaddr = be64_to_cpu(reth->vaddr);
1720                         int ok;
1721
1722                         ok = rvt_rkey_ok(qp, &e->rdma_sge, len, vaddr, rkey,
1723                                          IB_ACCESS_REMOTE_READ);
1724                         if (unlikely(!ok))
1725                                 goto unlock_done;
1726                 } else {
1727                         e->rdma_sge.vaddr = NULL;
1728                         e->rdma_sge.length = 0;
1729                         e->rdma_sge.sge_length = 0;
1730                 }
1731                 e->psn = psn;
1732                 if (old_req)
1733                         goto unlock_done;
1734                 qp->s_tail_ack_queue = prev;
1735                 break;
1736         }
1737
1738         case OP(COMPARE_SWAP):
1739         case OP(FETCH_ADD): {
1740                 /*
1741                  * If we didn't find the atomic request in the ack queue
1742                  * or the send tasklet is already backed up to send an
1743                  * earlier entry, we can ignore this request.
1744                  */
1745                 if (!e || e->opcode != (u8) opcode || old_req)
1746                         goto unlock_done;
1747                 qp->s_tail_ack_queue = prev;
1748                 break;
1749         }
1750
1751         default:
1752                 /*
1753                  * Ignore this operation if it doesn't request an ACK
1754                  * or an earlier RDMA read or atomic is going to be resent.
1755                  */
1756                 if (!(psn & IB_BTH_REQ_ACK) || old_req)
1757                         goto unlock_done;
1758                 /*
1759                  * Resend the most recent ACK if this request is
1760                  * after all the previous RDMA reads and atomics.
1761                  */
1762                 if (i == qp->r_head_ack_queue) {
1763                         spin_unlock_irqrestore(&qp->s_lock, flags);
1764                         qp->r_nak_state = 0;
1765                         qp->r_ack_psn = qp->r_psn - 1;
1766                         goto send_ack;
1767                 }
1768                 /*
1769                  * Try to send a simple ACK to work around a Mellanox bug
1770                  * which doesn't accept a RDMA read response or atomic
1771                  * response as an ACK for earlier SENDs or RDMA writes.
1772                  */
1773                 if (!(qp->s_flags & RVT_S_RESP_PENDING)) {
1774                         spin_unlock_irqrestore(&qp->s_lock, flags);
1775                         qp->r_nak_state = 0;
1776                         qp->r_ack_psn = qp->s_ack_queue[i].psn - 1;
1777                         goto send_ack;
1778                 }
1779                 /*
1780                  * Resend the RDMA read or atomic op which
1781                  * ACKs this duplicate request.
1782                  */
1783                 qp->s_tail_ack_queue = i;
1784                 break;
1785         }
1786         qp->s_ack_state = OP(ACKNOWLEDGE);
1787         qp->s_flags |= RVT_S_RESP_PENDING;
1788         qp->r_nak_state = 0;
1789         qib_schedule_send(qp);
1790
1791 unlock_done:
1792         spin_unlock_irqrestore(&qp->s_lock, flags);
1793 done:
1794         return 1;
1795
1796 send_ack:
1797         return 0;
1798 }
1799
1800 void qib_rc_error(struct rvt_qp *qp, enum ib_wc_status err)
1801 {
1802         unsigned long flags;
1803         int lastwqe;
1804
1805         spin_lock_irqsave(&qp->s_lock, flags);
1806         lastwqe = rvt_error_qp(qp, err);
1807         spin_unlock_irqrestore(&qp->s_lock, flags);
1808
1809         if (lastwqe) {
1810                 struct ib_event ev;
1811
1812                 ev.device = qp->ibqp.device;
1813                 ev.element.qp = &qp->ibqp;
1814                 ev.event = IB_EVENT_QP_LAST_WQE_REACHED;
1815                 qp->ibqp.event_handler(&ev, qp->ibqp.qp_context);
1816         }
1817 }
1818
1819 static inline void qib_update_ack_queue(struct rvt_qp *qp, unsigned n)
1820 {
1821         unsigned next;
1822
1823         next = n + 1;
1824         if (next > QIB_MAX_RDMA_ATOMIC)
1825                 next = 0;
1826         qp->s_tail_ack_queue = next;
1827         qp->s_ack_state = OP(ACKNOWLEDGE);
1828 }
1829
1830 /**
1831  * qib_rc_rcv - process an incoming RC packet
1832  * @rcd: the context pointer
1833  * @hdr: the header of this packet
1834  * @has_grh: true if the header has a GRH
1835  * @data: the packet data
1836  * @tlen: the packet length
1837  * @qp: the QP for this packet
1838  *
1839  * This is called from qib_qp_rcv() to process an incoming RC packet
1840  * for the given QP.
1841  * Called at interrupt level.
1842  */
1843 void qib_rc_rcv(struct qib_ctxtdata *rcd, struct ib_header *hdr,
1844                 int has_grh, void *data, u32 tlen, struct rvt_qp *qp)
1845 {
1846         struct qib_ibport *ibp = &rcd->ppd->ibport_data;
1847         struct ib_other_headers *ohdr;
1848         u32 opcode;
1849         u32 hdrsize;
1850         u32 psn;
1851         u32 pad;
1852         struct ib_wc wc;
1853         u32 pmtu = qp->pmtu;
1854         int diff;
1855         struct ib_reth *reth;
1856         unsigned long flags;
1857         int ret;
1858
1859         /* Check for GRH */
1860         if (!has_grh) {
1861                 ohdr = &hdr->u.oth;
1862                 hdrsize = 8 + 12;       /* LRH + BTH */
1863         } else {
1864                 ohdr = &hdr->u.l.oth;
1865                 hdrsize = 8 + 40 + 12;  /* LRH + GRH + BTH */
1866         }
1867
1868         opcode = be32_to_cpu(ohdr->bth[0]);
1869         if (qib_ruc_check_hdr(ibp, hdr, has_grh, qp, opcode))
1870                 return;
1871
1872         psn = be32_to_cpu(ohdr->bth[2]);
1873         opcode >>= 24;
1874
1875         /*
1876          * Process responses (ACKs) before anything else.  Note that the
1877          * packet sequence number will be for something in the send work
1878          * queue rather than the expected receive packet sequence number.
1879          * In other words, this QP is the requester.
1880          */
1881         if (opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
1882             opcode <= OP(ATOMIC_ACKNOWLEDGE)) {
1883                 qib_rc_rcv_resp(ibp, ohdr, data, tlen, qp, opcode, psn,
1884                                 hdrsize, pmtu, rcd);
1885                 return;
1886         }
1887
1888         /* Compute 24 bits worth of difference. */
1889         diff = qib_cmp24(psn, qp->r_psn);
1890         if (unlikely(diff)) {
1891                 if (qib_rc_rcv_error(ohdr, data, qp, opcode, psn, diff, rcd))
1892                         return;
1893                 goto send_ack;
1894         }
1895
1896         /* Check for opcode sequence errors. */
1897         switch (qp->r_state) {
1898         case OP(SEND_FIRST):
1899         case OP(SEND_MIDDLE):
1900                 if (opcode == OP(SEND_MIDDLE) ||
1901                     opcode == OP(SEND_LAST) ||
1902                     opcode == OP(SEND_LAST_WITH_IMMEDIATE))
1903                         break;
1904                 goto nack_inv;
1905
1906         case OP(RDMA_WRITE_FIRST):
1907         case OP(RDMA_WRITE_MIDDLE):
1908                 if (opcode == OP(RDMA_WRITE_MIDDLE) ||
1909                     opcode == OP(RDMA_WRITE_LAST) ||
1910                     opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
1911                         break;
1912                 goto nack_inv;
1913
1914         default:
1915                 if (opcode == OP(SEND_MIDDLE) ||
1916                     opcode == OP(SEND_LAST) ||
1917                     opcode == OP(SEND_LAST_WITH_IMMEDIATE) ||
1918                     opcode == OP(RDMA_WRITE_MIDDLE) ||
1919                     opcode == OP(RDMA_WRITE_LAST) ||
1920                     opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
1921                         goto nack_inv;
1922                 /*
1923                  * Note that it is up to the requester to not send a new
1924                  * RDMA read or atomic operation before receiving an ACK
1925                  * for the previous operation.
1926                  */
1927                 break;
1928         }
1929
1930         if (qp->state == IB_QPS_RTR && !(qp->r_flags & RVT_R_COMM_EST)) {
1931                 qp->r_flags |= RVT_R_COMM_EST;
1932                 if (qp->ibqp.event_handler) {
1933                         struct ib_event ev;
1934
1935                         ev.device = qp->ibqp.device;
1936                         ev.element.qp = &qp->ibqp;
1937                         ev.event = IB_EVENT_COMM_EST;
1938                         qp->ibqp.event_handler(&ev, qp->ibqp.qp_context);
1939                 }
1940         }
1941
1942         /* OK, process the packet. */
1943         switch (opcode) {
1944         case OP(SEND_FIRST):
1945                 ret = qib_get_rwqe(qp, 0);
1946                 if (ret < 0)
1947                         goto nack_op_err;
1948                 if (!ret)
1949                         goto rnr_nak;
1950                 qp->r_rcv_len = 0;
1951                 /* FALLTHROUGH */
1952         case OP(SEND_MIDDLE):
1953         case OP(RDMA_WRITE_MIDDLE):
1954 send_middle:
1955                 /* Check for invalid length PMTU or posted rwqe len. */
1956                 if (unlikely(tlen != (hdrsize + pmtu + 4)))
1957                         goto nack_inv;
1958                 qp->r_rcv_len += pmtu;
1959                 if (unlikely(qp->r_rcv_len > qp->r_len))
1960                         goto nack_inv;
1961                 qib_copy_sge(&qp->r_sge, data, pmtu, 1);
1962                 break;
1963
1964         case OP(RDMA_WRITE_LAST_WITH_IMMEDIATE):
1965                 /* consume RWQE */
1966                 ret = qib_get_rwqe(qp, 1);
1967                 if (ret < 0)
1968                         goto nack_op_err;
1969                 if (!ret)
1970                         goto rnr_nak;
1971                 goto send_last_imm;
1972
1973         case OP(SEND_ONLY):
1974         case OP(SEND_ONLY_WITH_IMMEDIATE):
1975                 ret = qib_get_rwqe(qp, 0);
1976                 if (ret < 0)
1977                         goto nack_op_err;
1978                 if (!ret)
1979                         goto rnr_nak;
1980                 qp->r_rcv_len = 0;
1981                 if (opcode == OP(SEND_ONLY))
1982                         goto no_immediate_data;
1983                 /* FALLTHROUGH for SEND_ONLY_WITH_IMMEDIATE */
1984         case OP(SEND_LAST_WITH_IMMEDIATE):
1985 send_last_imm:
1986                 wc.ex.imm_data = ohdr->u.imm_data;
1987                 hdrsize += 4;
1988                 wc.wc_flags = IB_WC_WITH_IMM;
1989                 goto send_last;
1990         case OP(SEND_LAST):
1991         case OP(RDMA_WRITE_LAST):
1992 no_immediate_data:
1993                 wc.wc_flags = 0;
1994                 wc.ex.imm_data = 0;
1995 send_last:
1996                 /* Get the number of bytes the message was padded by. */
1997                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1998                 /* Check for invalid length. */
1999                 /* XXX LAST len should be >= 1 */
2000                 if (unlikely(tlen < (hdrsize + pad + 4)))
2001                         goto nack_inv;
2002                 /* Don't count the CRC. */
2003                 tlen -= (hdrsize + pad + 4);
2004                 wc.byte_len = tlen + qp->r_rcv_len;
2005                 if (unlikely(wc.byte_len > qp->r_len))
2006                         goto nack_inv;
2007                 qib_copy_sge(&qp->r_sge, data, tlen, 1);
2008                 rvt_put_ss(&qp->r_sge);
2009                 qp->r_msn++;
2010                 if (!test_and_clear_bit(RVT_R_WRID_VALID, &qp->r_aflags))
2011                         break;
2012                 wc.wr_id = qp->r_wr_id;
2013                 wc.status = IB_WC_SUCCESS;
2014                 if (opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE) ||
2015                     opcode == OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE))
2016                         wc.opcode = IB_WC_RECV_RDMA_WITH_IMM;
2017                 else
2018                         wc.opcode = IB_WC_RECV;
2019                 wc.qp = &qp->ibqp;
2020                 wc.src_qp = qp->remote_qpn;
2021                 wc.slid = qp->remote_ah_attr.dlid;
2022                 wc.sl = qp->remote_ah_attr.sl;
2023                 /* zero fields that are N/A */
2024                 wc.vendor_err = 0;
2025                 wc.pkey_index = 0;
2026                 wc.dlid_path_bits = 0;
2027                 wc.port_num = 0;
2028                 /* Signal completion event if the solicited bit is set. */
2029                 rvt_cq_enter(ibcq_to_rvtcq(qp->ibqp.recv_cq), &wc,
2030                              (ohdr->bth[0] &
2031                               cpu_to_be32(IB_BTH_SOLICITED)) != 0);
2032                 break;
2033
2034         case OP(RDMA_WRITE_FIRST):
2035         case OP(RDMA_WRITE_ONLY):
2036         case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE):
2037                 if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_WRITE)))
2038                         goto nack_inv;
2039                 /* consume RWQE */
2040                 reth = &ohdr->u.rc.reth;
2041                 hdrsize += sizeof(*reth);
2042                 qp->r_len = be32_to_cpu(reth->length);
2043                 qp->r_rcv_len = 0;
2044                 qp->r_sge.sg_list = NULL;
2045                 if (qp->r_len != 0) {
2046                         u32 rkey = be32_to_cpu(reth->rkey);
2047                         u64 vaddr = be64_to_cpu(reth->vaddr);
2048                         int ok;
2049
2050                         /* Check rkey & NAK */
2051                         ok = rvt_rkey_ok(qp, &qp->r_sge.sge, qp->r_len, vaddr,
2052                                          rkey, IB_ACCESS_REMOTE_WRITE);
2053                         if (unlikely(!ok))
2054                                 goto nack_acc;
2055                         qp->r_sge.num_sge = 1;
2056                 } else {
2057                         qp->r_sge.num_sge = 0;
2058                         qp->r_sge.sge.mr = NULL;
2059                         qp->r_sge.sge.vaddr = NULL;
2060                         qp->r_sge.sge.length = 0;
2061                         qp->r_sge.sge.sge_length = 0;
2062                 }
2063                 if (opcode == OP(RDMA_WRITE_FIRST))
2064                         goto send_middle;
2065                 else if (opcode == OP(RDMA_WRITE_ONLY))
2066                         goto no_immediate_data;
2067                 ret = qib_get_rwqe(qp, 1);
2068                 if (ret < 0)
2069                         goto nack_op_err;
2070                 if (!ret)
2071                         goto rnr_nak;
2072                 wc.ex.imm_data = ohdr->u.rc.imm_data;
2073                 hdrsize += 4;
2074                 wc.wc_flags = IB_WC_WITH_IMM;
2075                 goto send_last;
2076
2077         case OP(RDMA_READ_REQUEST): {
2078                 struct rvt_ack_entry *e;
2079                 u32 len;
2080                 u8 next;
2081
2082                 if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_READ)))
2083                         goto nack_inv;
2084                 next = qp->r_head_ack_queue + 1;
2085                 /* s_ack_queue is size QIB_MAX_RDMA_ATOMIC+1 so use > not >= */
2086                 if (next > QIB_MAX_RDMA_ATOMIC)
2087                         next = 0;
2088                 spin_lock_irqsave(&qp->s_lock, flags);
2089                 if (unlikely(next == qp->s_tail_ack_queue)) {
2090                         if (!qp->s_ack_queue[next].sent)
2091                                 goto nack_inv_unlck;
2092                         qib_update_ack_queue(qp, next);
2093                 }
2094                 e = &qp->s_ack_queue[qp->r_head_ack_queue];
2095                 if (e->opcode == OP(RDMA_READ_REQUEST) && e->rdma_sge.mr) {
2096                         rvt_put_mr(e->rdma_sge.mr);
2097                         e->rdma_sge.mr = NULL;
2098                 }
2099                 reth = &ohdr->u.rc.reth;
2100                 len = be32_to_cpu(reth->length);
2101                 if (len) {
2102                         u32 rkey = be32_to_cpu(reth->rkey);
2103                         u64 vaddr = be64_to_cpu(reth->vaddr);
2104                         int ok;
2105
2106                         /* Check rkey & NAK */
2107                         ok = rvt_rkey_ok(qp, &e->rdma_sge, len, vaddr,
2108                                          rkey, IB_ACCESS_REMOTE_READ);
2109                         if (unlikely(!ok))
2110                                 goto nack_acc_unlck;
2111                         /*
2112                          * Update the next expected PSN.  We add 1 later
2113                          * below, so only add the remainder here.
2114                          */
2115                         if (len > pmtu)
2116                                 qp->r_psn += (len - 1) / pmtu;
2117                 } else {
2118                         e->rdma_sge.mr = NULL;
2119                         e->rdma_sge.vaddr = NULL;
2120                         e->rdma_sge.length = 0;
2121                         e->rdma_sge.sge_length = 0;
2122                 }
2123                 e->opcode = opcode;
2124                 e->sent = 0;
2125                 e->psn = psn;
2126                 e->lpsn = qp->r_psn;
2127                 /*
2128                  * We need to increment the MSN here instead of when we
2129                  * finish sending the result since a duplicate request would
2130                  * increment it more than once.
2131                  */
2132                 qp->r_msn++;
2133                 qp->r_psn++;
2134                 qp->r_state = opcode;
2135                 qp->r_nak_state = 0;
2136                 qp->r_head_ack_queue = next;
2137
2138                 /* Schedule the send tasklet. */
2139                 qp->s_flags |= RVT_S_RESP_PENDING;
2140                 qib_schedule_send(qp);
2141
2142                 goto sunlock;
2143         }
2144
2145         case OP(COMPARE_SWAP):
2146         case OP(FETCH_ADD): {
2147                 struct ib_atomic_eth *ateth;
2148                 struct rvt_ack_entry *e;
2149                 u64 vaddr;
2150                 atomic64_t *maddr;
2151                 u64 sdata;
2152                 u32 rkey;
2153                 u8 next;
2154
2155                 if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_ATOMIC)))
2156                         goto nack_inv;
2157                 next = qp->r_head_ack_queue + 1;
2158                 if (next > QIB_MAX_RDMA_ATOMIC)
2159                         next = 0;
2160                 spin_lock_irqsave(&qp->s_lock, flags);
2161                 if (unlikely(next == qp->s_tail_ack_queue)) {
2162                         if (!qp->s_ack_queue[next].sent)
2163                                 goto nack_inv_unlck;
2164                         qib_update_ack_queue(qp, next);
2165                 }
2166                 e = &qp->s_ack_queue[qp->r_head_ack_queue];
2167                 if (e->opcode == OP(RDMA_READ_REQUEST) && e->rdma_sge.mr) {
2168                         rvt_put_mr(e->rdma_sge.mr);
2169                         e->rdma_sge.mr = NULL;
2170                 }
2171                 ateth = &ohdr->u.atomic_eth;
2172                 vaddr = get_ib_ateth_vaddr(ateth);
2173                 if (unlikely(vaddr & (sizeof(u64) - 1)))
2174                         goto nack_inv_unlck;
2175                 rkey = be32_to_cpu(ateth->rkey);
2176                 /* Check rkey & NAK */
2177                 if (unlikely(!rvt_rkey_ok(qp, &qp->r_sge.sge, sizeof(u64),
2178                                           vaddr, rkey,
2179                                           IB_ACCESS_REMOTE_ATOMIC)))
2180                         goto nack_acc_unlck;
2181                 /* Perform atomic OP and save result. */
2182                 maddr = (atomic64_t *) qp->r_sge.sge.vaddr;
2183                 sdata = get_ib_ateth_swap(ateth);
2184                 e->atomic_data = (opcode == OP(FETCH_ADD)) ?
2185                         (u64) atomic64_add_return(sdata, maddr) - sdata :
2186                         (u64) cmpxchg((u64 *) qp->r_sge.sge.vaddr,
2187                                       get_ib_ateth_compare(ateth),
2188                                       sdata);
2189                 rvt_put_mr(qp->r_sge.sge.mr);
2190                 qp->r_sge.num_sge = 0;
2191                 e->opcode = opcode;
2192                 e->sent = 0;
2193                 e->psn = psn;
2194                 e->lpsn = psn;
2195                 qp->r_msn++;
2196                 qp->r_psn++;
2197                 qp->r_state = opcode;
2198                 qp->r_nak_state = 0;
2199                 qp->r_head_ack_queue = next;
2200
2201                 /* Schedule the send tasklet. */
2202                 qp->s_flags |= RVT_S_RESP_PENDING;
2203                 qib_schedule_send(qp);
2204
2205                 goto sunlock;
2206         }
2207
2208         default:
2209                 /* NAK unknown opcodes. */
2210                 goto nack_inv;
2211         }
2212         qp->r_psn++;
2213         qp->r_state = opcode;
2214         qp->r_ack_psn = psn;
2215         qp->r_nak_state = 0;
2216         /* Send an ACK if requested or required. */
2217         if (psn & (1 << 31))
2218                 goto send_ack;
2219         return;
2220
2221 rnr_nak:
2222         qp->r_nak_state = IB_RNR_NAK | qp->r_min_rnr_timer;
2223         qp->r_ack_psn = qp->r_psn;
2224         /* Queue RNR NAK for later */
2225         if (list_empty(&qp->rspwait)) {
2226                 qp->r_flags |= RVT_R_RSP_NAK;
2227                 rvt_get_qp(qp);
2228                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
2229         }
2230         return;
2231
2232 nack_op_err:
2233         qib_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
2234         qp->r_nak_state = IB_NAK_REMOTE_OPERATIONAL_ERROR;
2235         qp->r_ack_psn = qp->r_psn;
2236         /* Queue NAK for later */
2237         if (list_empty(&qp->rspwait)) {
2238                 qp->r_flags |= RVT_R_RSP_NAK;
2239                 rvt_get_qp(qp);
2240                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
2241         }
2242         return;
2243
2244 nack_inv_unlck:
2245         spin_unlock_irqrestore(&qp->s_lock, flags);
2246 nack_inv:
2247         qib_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
2248         qp->r_nak_state = IB_NAK_INVALID_REQUEST;
2249         qp->r_ack_psn = qp->r_psn;
2250         /* Queue NAK for later */
2251         if (list_empty(&qp->rspwait)) {
2252                 qp->r_flags |= RVT_R_RSP_NAK;
2253                 rvt_get_qp(qp);
2254                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
2255         }
2256         return;
2257
2258 nack_acc_unlck:
2259         spin_unlock_irqrestore(&qp->s_lock, flags);
2260 nack_acc:
2261         qib_rc_error(qp, IB_WC_LOC_PROT_ERR);
2262         qp->r_nak_state = IB_NAK_REMOTE_ACCESS_ERROR;
2263         qp->r_ack_psn = qp->r_psn;
2264 send_ack:
2265         qib_send_rc_ack(qp);
2266         return;
2267
2268 sunlock:
2269         spin_unlock_irqrestore(&qp->s_lock, flags);
2270 }