drivers/infiniband/hw/ipath/ipath_rc.c

   1 /*
   2  * Copyright (c) 2006 QLogic, Inc. 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 "ipath_verbs.h"
  35 #include "ipath_kernel.h"
  36
  37 /* cut down ridiculously long IB macro names */
  38 #define OP(x) IB_OPCODE_RC_##x
  39
  40 static u32 restart_sge(struct ipath_sge_state *ss, struct ipath_swqe *wqe,
  41                        u32 psn, u32 pmtu)
  42 {
  43         u32 len;
  44
  45         len = ((psn - wqe->psn) & IPATH_PSN_MASK) * pmtu;
  46         ss->sge = wqe->sg_list[0];
  47         ss->sg_list = wqe->sg_list + 1;
  48         ss->num_sge = wqe->wr.num_sge;
  49         ipath_skip_sge(ss, len);
  50         return wqe->length - len;
  51 }
  52
  53 /**
  54  * ipath_init_restart- initialize the qp->s_sge after a restart
  55  * @qp: the QP who's SGE we're restarting
  56  * @wqe: the work queue to initialize the QP's SGE from
  57  *
  58  * The QP s_lock should be held and interrupts disabled.
  59  */
  60 static void ipath_init_restart(struct ipath_qp *qp, struct ipath_swqe *wqe)
  61 {
  62         struct ipath_ibdev *dev;
  63
  64         qp->s_len = restart_sge(&qp->s_sge, wqe, qp->s_psn,
  65                                 ib_mtu_enum_to_int(qp->path_mtu));
  66         dev = to_idev(qp->ibqp.device);
  67         spin_lock(&dev->pending_lock);
  68         if (list_empty(&qp->timerwait))
  69                 list_add_tail(&qp->timerwait,
  70                               &dev->pending[dev->pending_index]);
  71         spin_unlock(&dev->pending_lock);
  72 }
  73
  74 /**
  75  * ipath_make_rc_ack - construct a response packet (ACK, NAK, or RDMA read)
  76  * @qp: a pointer to the QP
  77  * @ohdr: a pointer to the IB header being constructed
  78  * @pmtu: the path MTU
  79  *
  80  * Return 1 if constructed; otherwise, return 0.
  81  * Note that we are in the responder's side of the QP context.
  82  * Note the QP s_lock must be held.
  83  */
  84 static int ipath_make_rc_ack(struct ipath_qp *qp,
  85                              struct ipath_other_headers *ohdr,
  86                              u32 pmtu, u32 *bth0p, u32 *bth2p)
  87 {
  88         struct ipath_ack_entry *e;
  89         u32 hwords;
  90         u32 len;
  91         u32 bth0;
  92         u32 bth2;
  93
  94         /* header size in 32-bit words LRH+BTH = (8+12)/4. */
  95         hwords = 5;
  96
  97         switch (qp->s_ack_state) {
  98         case OP(RDMA_READ_RESPONSE_LAST):
  99         case OP(RDMA_READ_RESPONSE_ONLY):
 100         case OP(ATOMIC_ACKNOWLEDGE):
 101                 /*
 102                  * We can increment the tail pointer now that the last
 103                  * response has been sent instead of only being
 104                  * constructed.
 105                  */
 106                 if (++qp->s_tail_ack_queue > IPATH_MAX_RDMA_ATOMIC)
 107                         qp->s_tail_ack_queue = 0;
 108                 /* FALLTHROUGH */
 109         case OP(SEND_ONLY):
 110         case OP(ACKNOWLEDGE):
 111                 /* Check for no next entry in the queue. */
 112                 if (qp->r_head_ack_queue == qp->s_tail_ack_queue) {
 113                         if (qp->s_flags & IPATH_S_ACK_PENDING)
 114                                 goto normal;
 115                         qp->s_ack_state = OP(ACKNOWLEDGE);
 116                         goto bail;
 117                 }
 118
 119                 e = &qp->s_ack_queue[qp->s_tail_ack_queue];
 120                 if (e->opcode == OP(RDMA_READ_REQUEST)) {
 121                         /* Copy SGE state in case we need to resend */
 122                         qp->s_ack_rdma_sge = e->rdma_sge;
 123                         qp->s_cur_sge = &qp->s_ack_rdma_sge;
 124                         len = e->rdma_sge.sge.sge_length;
 125                         if (len > pmtu) {
 126                                 len = pmtu;
 127                                 qp->s_ack_state = OP(RDMA_READ_RESPONSE_FIRST);
 128                         } else
 129                                 qp->s_ack_state = OP(RDMA_READ_RESPONSE_ONLY);
 130                         ohdr->u.aeth = ipath_compute_aeth(qp);
 131                         hwords++;
 132                         qp->s_ack_rdma_psn = e->psn;
 133                         bth2 = qp->s_ack_rdma_psn++ & IPATH_PSN_MASK;
 134                 } else {
 135                         /* COMPARE_SWAP or FETCH_ADD */
 136                         qp->s_cur_sge = NULL;
 137                         len = 0;
 138                         qp->s_ack_state = OP(ATOMIC_ACKNOWLEDGE);
 139                         ohdr->u.at.aeth = ipath_compute_aeth(qp);
 140                         ohdr->u.at.atomic_ack_eth[0] =
 141                                 cpu_to_be32(e->atomic_data >> 32);
 142                         ohdr->u.at.atomic_ack_eth[1] =
 143                                 cpu_to_be32(e->atomic_data);
 144                         hwords += sizeof(ohdr->u.at) / sizeof(u32);
 145                         bth2 = e->psn;
 146                 }
 147                 bth0 = qp->s_ack_state << 24;
 148                 break;
 149
 150         case OP(RDMA_READ_RESPONSE_FIRST):
 151                 qp->s_ack_state = OP(RDMA_READ_RESPONSE_MIDDLE);
 152                 /* FALLTHROUGH */
 153         case OP(RDMA_READ_RESPONSE_MIDDLE):
 154                 len = qp->s_ack_rdma_sge.sge.sge_length;
 155                 if (len > pmtu)
 156                         len = pmtu;
 157                 else {
 158                         ohdr->u.aeth = ipath_compute_aeth(qp);
 159                         hwords++;
 160                         qp->s_ack_state = OP(RDMA_READ_RESPONSE_LAST);
 161                 }
 162                 bth0 = qp->s_ack_state << 24;
 163                 bth2 = qp->s_ack_rdma_psn++ & IPATH_PSN_MASK;
 164                 break;
 165
 166         default:
 167         normal:
 168                 /*
 169                  * Send a regular ACK.
 170                  * Set the s_ack_state so we wait until after sending
 171                  * the ACK before setting s_ack_state to ACKNOWLEDGE
 172                  * (see above).
 173                  */
 174                 qp->s_ack_state = OP(SEND_ONLY);
 175                 qp->s_flags &= ~IPATH_S_ACK_PENDING;
 176                 qp->s_cur_sge = NULL;
 177                 if (qp->s_nak_state)
 178                         ohdr->u.aeth =
 179                                 cpu_to_be32((qp->r_msn & IPATH_MSN_MASK) |
 180                                             (qp->s_nak_state <<
 181                                              IPATH_AETH_CREDIT_SHIFT));
 182                 else
 183                         ohdr->u.aeth = ipath_compute_aeth(qp);
 184                 hwords++;
 185                 len = 0;
 186                 bth0 = OP(ACKNOWLEDGE) << 24;
 187                 bth2 = qp->s_ack_psn & IPATH_PSN_MASK;
 188         }
 189         qp->s_hdrwords = hwords;
 190         qp->s_cur_size = len;
 191         *bth0p = bth0 | (1 << 22); /* Set M bit */
 192         *bth2p = bth2;
 193         return 1;
 194
 195 bail:
 196         return 0;
 197 }
 198
 199 /**
 200  * ipath_make_rc_req - construct a request packet (SEND, RDMA r/w, ATOMIC)
 201  * @qp: a pointer to the QP
 202  * @ohdr: a pointer to the IB header being constructed
 203  * @pmtu: the path MTU
 204  * @bth0p: pointer to the BTH opcode word
 205  * @bth2p: pointer to the BTH PSN word
 206  *
 207  * Return 1 if constructed; otherwise, return 0.
 208  * Note the QP s_lock must be held and interrupts disabled.
 209  */
 210 int ipath_make_rc_req(struct ipath_qp *qp,
 211                       struct ipath_other_headers *ohdr,
 212                       u32 pmtu, u32 *bth0p, u32 *bth2p)
 213 {
 214         struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
 215         struct ipath_sge_state *ss;
 216         struct ipath_swqe *wqe;
 217         u32 hwords;
 218         u32 len;
 219         u32 bth0;
 220         u32 bth2;
 221         char newreq;
 222
 223         /* Sending responses has higher priority over sending requests. */
 224         if ((qp->r_head_ack_queue != qp->s_tail_ack_queue ||
 225              (qp->s_flags & IPATH_S_ACK_PENDING) ||
 226              qp->s_ack_state != OP(ACKNOWLEDGE)) &&
 227             ipath_make_rc_ack(qp, ohdr, pmtu, bth0p, bth2p))
 228                 goto done;
 229
 230         if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_SEND_OK) ||
 231             qp->s_rnr_timeout || qp->s_wait_credit)
 232                 goto bail;
 233
 234         /* Limit the number of packets sent without an ACK. */
 235         if (ipath_cmp24(qp->s_psn, qp->s_last_psn + IPATH_PSN_CREDIT) > 0) {
 236                 qp->s_wait_credit = 1;
 237                 dev->n_rc_stalls++;
 238                 goto bail;
 239         }
 240
 241         /* header size in 32-bit words LRH+BTH = (8+12)/4. */
 242         hwords = 5;
 243         bth0 = 1 << 22; /* Set M bit */
 244
 245         /* Send a request. */
 246         wqe = get_swqe_ptr(qp, qp->s_cur);
 247         switch (qp->s_state) {
 248         default:
 249                 /*
 250                  * Resend an old request or start a new one.
 251                  *
 252                  * We keep track of the current SWQE so that
 253                  * we don't reset the "furthest progress" state
 254                  * if we need to back up.
 255                  */
 256                 newreq = 0;
 257                 if (qp->s_cur == qp->s_tail) {
 258                         /* Check if send work queue is empty. */
 259                         if (qp->s_tail == qp->s_head)
 260                                 goto bail;
 261                         /*
 262                          * If a fence is requested, wait for previous
 263                          * RDMA read and atomic operations to finish.
 264                          */
 265                         if ((wqe->wr.send_flags & IB_SEND_FENCE) &&
 266                             qp->s_num_rd_atomic) {
 267                                 qp->s_flags |= IPATH_S_FENCE_PENDING;
 268                                 goto bail;
 269                         }
 270                         wqe->psn = qp->s_next_psn;
 271                         newreq = 1;
 272                 }
 273                 /*
 274                  * Note that we have to be careful not to modify the
 275                  * original work request since we may need to resend
 276                  * it.
 277                  */
 278                 len = wqe->length;
 279                 ss = &qp->s_sge;
 280                 bth2 = 0;
 281                 switch (wqe->wr.opcode) {
 282                 case IB_WR_SEND:
 283                 case IB_WR_SEND_WITH_IMM:
 284                         /* If no credit, return. */
 285                         if (qp->s_lsn != (u32) -1 &&
 286                             ipath_cmp24(wqe->ssn, qp->s_lsn + 1) > 0)
 287                                 goto bail;
 288                         wqe->lpsn = wqe->psn;
 289                         if (len > pmtu) {
 290                                 wqe->lpsn += (len - 1) / pmtu;
 291                                 qp->s_state = OP(SEND_FIRST);
 292                                 len = pmtu;
 293                                 break;
 294                         }
 295                         if (wqe->wr.opcode == IB_WR_SEND)
 296                                 qp->s_state = OP(SEND_ONLY);
 297                         else {
 298                                 qp->s_state = OP(SEND_ONLY_WITH_IMMEDIATE);
 299                                 /* Immediate data comes after the BTH */
 300                                 ohdr->u.imm_data = wqe->wr.imm_data;
 301                                 hwords += 1;
 302                         }
 303                         if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 304                                 bth0 |= 1 << 23;
 305                         bth2 = 1 << 31; /* Request ACK. */
 306                         if (++qp->s_cur == qp->s_size)
 307                                 qp->s_cur = 0;
 308                         break;
 309
 310                 case IB_WR_RDMA_WRITE:
 311                         if (newreq && qp->s_lsn != (u32) -1)
 312                                 qp->s_lsn++;
 313                         /* FALLTHROUGH */
 314                 case IB_WR_RDMA_WRITE_WITH_IMM:
 315                         /* If no credit, return. */
 316                         if (qp->s_lsn != (u32) -1 &&
 317                             ipath_cmp24(wqe->ssn, qp->s_lsn + 1) > 0)
 318                                 goto bail;
 319                         ohdr->u.rc.reth.vaddr =
 320                                 cpu_to_be64(wqe->wr.wr.rdma.remote_addr);
 321                         ohdr->u.rc.reth.rkey =
 322                                 cpu_to_be32(wqe->wr.wr.rdma.rkey);
 323                         ohdr->u.rc.reth.length = cpu_to_be32(len);
 324                         hwords += sizeof(struct ib_reth) / sizeof(u32);
 325                         wqe->lpsn = wqe->psn;
 326                         if (len > pmtu) {
 327                                 wqe->lpsn += (len - 1) / pmtu;
 328                                 qp->s_state = OP(RDMA_WRITE_FIRST);
 329                                 len = pmtu;
 330                                 break;
 331                         }
 332                         if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
 333                                 qp->s_state = OP(RDMA_WRITE_ONLY);
 334                         else {
 335                                 qp->s_state =
 336                                         OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE);
 337                                 /* Immediate data comes after RETH */
 338                                 ohdr->u.rc.imm_data = wqe->wr.imm_data;
 339                                 hwords += 1;
 340                                 if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 341                                         bth0 |= 1 << 23;
 342                         }
 343                         bth2 = 1 << 31; /* Request ACK. */
 344                         if (++qp->s_cur == qp->s_size)
 345                                 qp->s_cur = 0;
 346                         break;
 347
 348                 case IB_WR_RDMA_READ:
 349                         /*
 350                          * Don't allow more operations to be started
 351                          * than the QP limits allow.
 352                          */
 353                         if (newreq) {
 354                                 if (qp->s_num_rd_atomic >=
 355                                     qp->s_max_rd_atomic) {
 356                                         qp->s_flags |= IPATH_S_RDMAR_PENDING;
 357                                         goto bail;
 358                                 }
 359                                 qp->s_num_rd_atomic++;
 360                                 if (qp->s_lsn != (u32) -1)
 361                                         qp->s_lsn++;
 362                                 /*
 363                                  * Adjust s_next_psn to count the
 364                                  * expected number of responses.
 365                                  */
 366                                 if (len > pmtu)
 367                                         qp->s_next_psn += (len - 1) / pmtu;
 368                                 wqe->lpsn = qp->s_next_psn++;
 369                         }
 370                         ohdr->u.rc.reth.vaddr =
 371                                 cpu_to_be64(wqe->wr.wr.rdma.remote_addr);
 372                         ohdr->u.rc.reth.rkey =
 373                                 cpu_to_be32(wqe->wr.wr.rdma.rkey);
 374                         ohdr->u.rc.reth.length = cpu_to_be32(len);
 375                         qp->s_state = OP(RDMA_READ_REQUEST);
 376                         hwords += sizeof(ohdr->u.rc.reth) / sizeof(u32);
 377                         ss = NULL;
 378                         len = 0;
 379                         if (++qp->s_cur == qp->s_size)
 380                                 qp->s_cur = 0;
 381                         break;
 382
 383                 case IB_WR_ATOMIC_CMP_AND_SWP:
 384                 case IB_WR_ATOMIC_FETCH_AND_ADD:
 385                         /*
 386                          * Don't allow more operations to be started
 387                          * than the QP limits allow.
 388                          */
 389                         if (newreq) {
 390                                 if (qp->s_num_rd_atomic >=
 391                                     qp->s_max_rd_atomic) {
 392                                         qp->s_flags |= IPATH_S_RDMAR_PENDING;
 393                                         goto bail;
 394                                 }
 395                                 qp->s_num_rd_atomic++;
 396                                 if (qp->s_lsn != (u32) -1)
 397                                         qp->s_lsn++;
 398                                 wqe->lpsn = wqe->psn;
 399                         }
 400                         if (wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP) {
 401                                 qp->s_state = OP(COMPARE_SWAP);
 402                                 ohdr->u.atomic_eth.swap_data = cpu_to_be64(
 403                                         wqe->wr.wr.atomic.swap);
 404                                 ohdr->u.atomic_eth.compare_data = cpu_to_be64(
 405                                         wqe->wr.wr.atomic.compare_add);
 406                         } else {
 407                                 qp->s_state = OP(FETCH_ADD);
 408                                 ohdr->u.atomic_eth.swap_data = cpu_to_be64(
 409                                         wqe->wr.wr.atomic.compare_add);
 410                                 ohdr->u.atomic_eth.compare_data = 0;
 411                         }
 412                         ohdr->u.atomic_eth.vaddr[0] = cpu_to_be32(
 413                                 wqe->wr.wr.atomic.remote_addr >> 32);
 414                         ohdr->u.atomic_eth.vaddr[1] = cpu_to_be32(
 415                                 wqe->wr.wr.atomic.remote_addr);
 416                         ohdr->u.atomic_eth.rkey = cpu_to_be32(
 417                                 wqe->wr.wr.atomic.rkey);
 418                         hwords += sizeof(struct ib_atomic_eth) / sizeof(u32);
 419                         ss = NULL;
 420                         len = 0;
 421                         if (++qp->s_cur == qp->s_size)
 422                                 qp->s_cur = 0;
 423                         break;
 424
 425                 default:
 426                         goto bail;
 427                 }
 428                 qp->s_sge.sge = wqe->sg_list[0];
 429                 qp->s_sge.sg_list = wqe->sg_list + 1;
 430                 qp->s_sge.num_sge = wqe->wr.num_sge;
 431                 qp->s_len = wqe->length;
 432                 if (newreq) {
 433                         qp->s_tail++;
 434                         if (qp->s_tail >= qp->s_size)
 435                                 qp->s_tail = 0;
 436                 }
 437                 bth2 |= qp->s_psn & IPATH_PSN_MASK;
 438                 if (wqe->wr.opcode == IB_WR_RDMA_READ)
 439                         qp->s_psn = wqe->lpsn + 1;
 440                 else {
 441                         qp->s_psn++;
 442                         if (ipath_cmp24(qp->s_psn, qp->s_next_psn) > 0)
 443                                 qp->s_next_psn = qp->s_psn;
 444                 }
 445                 /*
 446                  * Put the QP on the pending list so lost ACKs will cause
 447                  * a retry.  More than one request can be pending so the
 448                  * QP may already be on the dev->pending list.
 449                  */
 450                 spin_lock(&dev->pending_lock);
 451                 if (list_empty(&qp->timerwait))
 452                         list_add_tail(&qp->timerwait,
 453                                       &dev->pending[dev->pending_index]);
 454                 spin_unlock(&dev->pending_lock);
 455                 break;
 456
 457         case OP(RDMA_READ_RESPONSE_FIRST):
 458                 /*
 459                  * This case can only happen if a send is restarted.
 460                  * See ipath_restart_rc().
 461                  */
 462                 ipath_init_restart(qp, wqe);
 463                 /* FALLTHROUGH */
 464         case OP(SEND_FIRST):
 465                 qp->s_state = OP(SEND_MIDDLE);
 466                 /* FALLTHROUGH */
 467         case OP(SEND_MIDDLE):
 468                 bth2 = qp->s_psn++ & IPATH_PSN_MASK;
 469                 if (ipath_cmp24(qp->s_psn, qp->s_next_psn) > 0)
 470                         qp->s_next_psn = qp->s_psn;
 471                 ss = &qp->s_sge;
 472                 len = qp->s_len;
 473                 if (len > pmtu) {
 474                         len = pmtu;
 475                         break;
 476                 }
 477                 if (wqe->wr.opcode == IB_WR_SEND)
 478                         qp->s_state = OP(SEND_LAST);
 479                 else {
 480                         qp->s_state = OP(SEND_LAST_WITH_IMMEDIATE);
 481                         /* Immediate data comes after the BTH */
 482                         ohdr->u.imm_data = wqe->wr.imm_data;
 483                         hwords += 1;
 484                 }
 485                 if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 486                         bth0 |= 1 << 23;
 487                 bth2 |= 1 << 31;        /* Request ACK. */
 488                 qp->s_cur++;
 489                 if (qp->s_cur >= qp->s_size)
 490                         qp->s_cur = 0;
 491                 break;
 492
 493         case OP(RDMA_READ_RESPONSE_LAST):
 494                 /*
 495                  * This case can only happen if a RDMA write is restarted.
 496                  * See ipath_restart_rc().
 497                  */
 498                 ipath_init_restart(qp, wqe);
 499                 /* FALLTHROUGH */
 500         case OP(RDMA_WRITE_FIRST):
 501                 qp->s_state = OP(RDMA_WRITE_MIDDLE);
 502                 /* FALLTHROUGH */
 503         case OP(RDMA_WRITE_MIDDLE):
 504                 bth2 = qp->s_psn++ & IPATH_PSN_MASK;
 505                 if (ipath_cmp24(qp->s_psn, qp->s_next_psn) > 0)
 506                         qp->s_next_psn = qp->s_psn;
 507                 ss = &qp->s_sge;
 508                 len = qp->s_len;
 509                 if (len > pmtu) {
 510                         len = pmtu;
 511                         break;
 512                 }
 513                 if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
 514                         qp->s_state = OP(RDMA_WRITE_LAST);
 515                 else {
 516                         qp->s_state = OP(RDMA_WRITE_LAST_WITH_IMMEDIATE);
 517                         /* Immediate data comes after the BTH */
 518                         ohdr->u.imm_data = wqe->wr.imm_data;
 519                         hwords += 1;
 520                         if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 521                                 bth0 |= 1 << 23;
 522                 }
 523                 bth2 |= 1 << 31;        /* Request ACK. */
 524                 qp->s_cur++;
 525                 if (qp->s_cur >= qp->s_size)
 526                         qp->s_cur = 0;
 527                 break;
 528
 529         case OP(RDMA_READ_RESPONSE_MIDDLE):
 530                 /*
 531                  * This case can only happen if a RDMA read is restarted.
 532                  * See ipath_restart_rc().
 533                  */
 534                 ipath_init_restart(qp, wqe);
 535                 len = ((qp->s_psn - wqe->psn) & IPATH_PSN_MASK) * pmtu;
 536                 ohdr->u.rc.reth.vaddr =
 537                         cpu_to_be64(wqe->wr.wr.rdma.remote_addr + len);
 538                 ohdr->u.rc.reth.rkey =
 539                         cpu_to_be32(wqe->wr.wr.rdma.rkey);
 540                 ohdr->u.rc.reth.length = cpu_to_be32(qp->s_len);
 541                 qp->s_state = OP(RDMA_READ_REQUEST);
 542                 hwords += sizeof(ohdr->u.rc.reth) / sizeof(u32);
 543                 bth2 = qp->s_psn++ & IPATH_PSN_MASK;
 544                 if (ipath_cmp24(qp->s_psn, qp->s_next_psn) > 0)
 545                         qp->s_next_psn = qp->s_psn;
 546                 ss = NULL;
 547                 len = 0;
 548                 qp->s_cur++;
 549                 if (qp->s_cur == qp->s_size)
 550                         qp->s_cur = 0;
 551                 break;
 552         }
 553         if (ipath_cmp24(qp->s_psn, qp->s_last_psn + IPATH_PSN_CREDIT - 1) >= 0)
 554                 bth2 |= 1 << 31;        /* Request ACK. */
 555         qp->s_len -= len;
 556         qp->s_hdrwords = hwords;
 557         qp->s_cur_sge = ss;
 558         qp->s_cur_size = len;
 559         *bth0p = bth0 | (qp->s_state << 24);
 560         *bth2p = bth2;
 561 done:
 562         return 1;
 563
 564 bail:
 565         return 0;
 566 }
 567
 568 /**
 569  * send_rc_ack - Construct an ACK packet and send it
 570  * @qp: a pointer to the QP
 571  *
 572  * This is called from ipath_rc_rcv() and only uses the receive
 573  * side QP state.
 574  * Note that RDMA reads and atomics are handled in the
 575  * send side QP state and tasklet.
 576  */
 577 static void send_rc_ack(struct ipath_qp *qp)
 578 {
 579         struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
 580         u16 lrh0;
 581         u32 bth0;
 582         u32 hwords;
 583         struct ipath_ib_header hdr;
 584         struct ipath_other_headers *ohdr;
 585         unsigned long flags;
 586
 587         /* Don't send ACK or NAK if a RDMA read or atomic is pending. */
 588         if (qp->r_head_ack_queue != qp->s_tail_ack_queue ||
 589             (qp->s_flags & IPATH_S_ACK_PENDING) ||
 590             qp->s_ack_state != OP(ACKNOWLEDGE))
 591                 goto queue_ack;
 592
 593         /* Construct the header. */
 594         ohdr = &hdr.u.oth;
 595         lrh0 = IPATH_LRH_BTH;
 596         /* header size in 32-bit words LRH+BTH+AETH = (8+12+4)/4. */
 597         hwords = 6;
 598         if (unlikely(qp->remote_ah_attr.ah_flags & IB_AH_GRH)) {
 599                 hwords += ipath_make_grh(dev, &hdr.u.l.grh,
 600                                          &qp->remote_ah_attr.grh,
 601                                          hwords, 0);
 602                 ohdr = &hdr.u.l.oth;
 603                 lrh0 = IPATH_LRH_GRH;
 604         }
 605         /* read pkey_index w/o lock (its atomic) */
 606         bth0 = ipath_get_pkey(dev->dd, qp->s_pkey_index) |
 607                 (OP(ACKNOWLEDGE) << 24) | (1 << 22);
 608         if (qp->r_nak_state)
 609                 ohdr->u.aeth = cpu_to_be32((qp->r_msn & IPATH_MSN_MASK) |
 610                                             (qp->r_nak_state <<
 611                                              IPATH_AETH_CREDIT_SHIFT));
 612         else
 613                 ohdr->u.aeth = ipath_compute_aeth(qp);
 614         lrh0 |= qp->remote_ah_attr.sl << 4;
 615         hdr.lrh[0] = cpu_to_be16(lrh0);
 616         hdr.lrh[1] = cpu_to_be16(qp->remote_ah_attr.dlid);
 617         hdr.lrh[2] = cpu_to_be16(hwords + SIZE_OF_CRC);
 618         hdr.lrh[3] = cpu_to_be16(dev->dd->ipath_lid);
 619         ohdr->bth[0] = cpu_to_be32(bth0);
 620         ohdr->bth[1] = cpu_to_be32(qp->remote_qpn);
 621         ohdr->bth[2] = cpu_to_be32(qp->r_ack_psn & IPATH_PSN_MASK);
 622
 623         /*
 624          * If we can send the ACK, clear the ACK state.
 625          */
 626         if (ipath_verbs_send(dev->dd, hwords, (u32 *) &hdr, 0, NULL) == 0) {
 627                 dev->n_unicast_xmit++;
 628                 goto done;
 629         }
 630
 631         /*
 632          * We are out of PIO buffers at the moment.
 633          * Pass responsibility for sending the ACK to the
 634          * send tasklet so that when a PIO buffer becomes
 635          * available, the ACK is sent ahead of other outgoing
 636          * packets.
 637          */
 638         dev->n_rc_qacks++;
 639
 640 queue_ack:
 641         spin_lock_irqsave(&qp->s_lock, flags);
 642         qp->s_flags |= IPATH_S_ACK_PENDING;
 643         qp->s_nak_state = qp->r_nak_state;
 644         qp->s_ack_psn = qp->r_ack_psn;
 645         spin_unlock_irqrestore(&qp->s_lock, flags);
 646
 647         /* Call ipath_do_rc_send() in another thread. */
 648         tasklet_hi_schedule(&qp->s_task);
 649
 650 done:
 651         return;
 652 }
 653
 654 /**
 655  * reset_psn - reset the QP state to send starting from PSN
 656  * @qp: the QP
 657  * @psn: the packet sequence number to restart at
 658  *
 659  * This is called from ipath_rc_rcv() to process an incoming RC ACK
 660  * for the given QP.
 661  * Called at interrupt level with the QP s_lock held.
 662  */
 663 static void reset_psn(struct ipath_qp *qp, u32 psn)
 664 {
 665         u32 n = qp->s_last;
 666         struct ipath_swqe *wqe = get_swqe_ptr(qp, n);
 667         u32 opcode;
 668
 669         qp->s_cur = n;
 670
 671         /*
 672          * If we are starting the request from the beginning,
 673          * let the normal send code handle initialization.
 674          */
 675         if (ipath_cmp24(psn, wqe->psn) <= 0) {
 676                 qp->s_state = OP(SEND_LAST);
 677                 goto done;
 678         }
 679
 680         /* Find the work request opcode corresponding to the given PSN. */
 681         opcode = wqe->wr.opcode;
 682         for (;;) {
 683                 int diff;
 684
 685                 if (++n == qp->s_size)
 686                         n = 0;
 687                 if (n == qp->s_tail)
 688                         break;
 689                 wqe = get_swqe_ptr(qp, n);
 690                 diff = ipath_cmp24(psn, wqe->psn);
 691                 if (diff < 0)
 692                         break;
 693                 qp->s_cur = n;
 694                 /*
 695                  * If we are starting the request from the beginning,
 696                  * let the normal send code handle initialization.
 697                  */
 698                 if (diff == 0) {
 699                         qp->s_state = OP(SEND_LAST);
 700                         goto done;
 701                 }
 702                 opcode = wqe->wr.opcode;
 703         }
 704
 705         /*
 706          * Set the state to restart in the middle of a request.
 707          * Don't change the s_sge, s_cur_sge, or s_cur_size.
 708          * See ipath_do_rc_send().
 709          */
 710         switch (opcode) {
 711         case IB_WR_SEND:
 712         case IB_WR_SEND_WITH_IMM:
 713                 qp->s_state = OP(RDMA_READ_RESPONSE_FIRST);
 714                 break;
 715
 716         case IB_WR_RDMA_WRITE:
 717         case IB_WR_RDMA_WRITE_WITH_IMM:
 718                 qp->s_state = OP(RDMA_READ_RESPONSE_LAST);
 719                 break;
 720
 721         case IB_WR_RDMA_READ:
 722                 qp->s_state = OP(RDMA_READ_RESPONSE_MIDDLE);
 723                 break;
 724
 725         default:
 726                 /*
 727                  * This case shouldn't happen since its only
 728                  * one PSN per req.
 729                  */
 730                 qp->s_state = OP(SEND_LAST);
 731         }
 732 done:
 733         qp->s_psn = psn;
 734 }
 735
 736 /**
 737  * ipath_restart_rc - back up requester to resend the last un-ACKed request
 738  * @qp: the QP to restart
 739  * @psn: packet sequence number for the request
 740  * @wc: the work completion request
 741  *
 742  * The QP s_lock should be held and interrupts disabled.
 743  */
 744 void ipath_restart_rc(struct ipath_qp *qp, u32 psn, struct ib_wc *wc)
 745 {
 746         struct ipath_swqe *wqe = get_swqe_ptr(qp, qp->s_last);
 747         struct ipath_ibdev *dev;
 748
 749         if (qp->s_retry == 0) {
 750                 wc->wr_id = wqe->wr.wr_id;
 751                 wc->status = IB_WC_RETRY_EXC_ERR;
 752                 wc->opcode = ib_ipath_wc_opcode[wqe->wr.opcode];
 753                 wc->vendor_err = 0;
 754                 wc->byte_len = 0;
 755                 wc->qp = &qp->ibqp;
 756                 wc->src_qp = qp->remote_qpn;
 757                 wc->pkey_index = 0;
 758                 wc->slid = qp->remote_ah_attr.dlid;
 759                 wc->sl = qp->remote_ah_attr.sl;
 760                 wc->dlid_path_bits = 0;
 761                 wc->port_num = 0;
 762                 ipath_sqerror_qp(qp, wc);
 763                 goto bail;
 764         }
 765         qp->s_retry--;
 766
 767         /*
 768          * Remove the QP from the timeout queue.
 769          * Note: it may already have been removed by ipath_ib_timer().
 770          */
 771         dev = to_idev(qp->ibqp.device);
 772         spin_lock(&dev->pending_lock);
 773         if (!list_empty(&qp->timerwait))
 774                 list_del_init(&qp->timerwait);
 775         spin_unlock(&dev->pending_lock);
 776
 777         if (wqe->wr.opcode == IB_WR_RDMA_READ)
 778                 dev->n_rc_resends++;
 779         else
 780                 dev->n_rc_resends += (qp->s_psn - psn) & IPATH_PSN_MASK;
 781
 782         reset_psn(qp, psn);
 783         tasklet_hi_schedule(&qp->s_task);
 784
 785 bail:
 786         return;
 787 }
 788
 789 static inline void update_last_psn(struct ipath_qp *qp, u32 psn)
 790 {
 791         if (qp->s_wait_credit) {
 792                 qp->s_wait_credit = 0;
 793                 tasklet_hi_schedule(&qp->s_task);
 794         }
 795         qp->s_last_psn = psn;
 796 }
 797
 798 /**
 799  * do_rc_ack - process an incoming RC ACK
 800  * @qp: the QP the ACK came in on
 801  * @psn: the packet sequence number of the ACK
 802  * @opcode: the opcode of the request that resulted in the ACK
 803  *
 804  * This is called from ipath_rc_rcv_resp() to process an incoming RC ACK
 805  * for the given QP.
 806  * Called at interrupt level with the QP s_lock held and interrupts disabled.
 807  * Returns 1 if OK, 0 if current operation should be aborted (NAK).
 808  */
 809 static int do_rc_ack(struct ipath_qp *qp, u32 aeth, u32 psn, int opcode,
 810                      u64 val)
 811 {
 812         struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
 813         struct ib_wc wc;
 814         struct ipath_swqe *wqe;
 815         int ret = 0;
 816         u32 ack_psn;
 817         int diff;
 818
 819         /*
 820          * Remove the QP from the timeout queue (or RNR timeout queue).
 821          * If ipath_ib_timer() has already removed it,
 822          * it's OK since we hold the QP s_lock and ipath_restart_rc()
 823          * just won't find anything to restart if we ACK everything.
 824          */
 825         spin_lock(&dev->pending_lock);
 826         if (!list_empty(&qp->timerwait))
 827                 list_del_init(&qp->timerwait);
 828         spin_unlock(&dev->pending_lock);
 829
 830         /*
 831          * Note that NAKs implicitly ACK outstanding SEND and RDMA write
 832          * requests and implicitly NAK RDMA read and atomic requests issued
 833          * before the NAK'ed request.  The MSN won't include the NAK'ed
 834          * request but will include an ACK'ed request(s).
 835          */
 836         ack_psn = psn;
 837         if (aeth >> 29)
 838                 ack_psn--;
 839         wqe = get_swqe_ptr(qp, qp->s_last);
 840
 841         /*
 842          * The MSN might be for a later WQE than the PSN indicates so
 843          * only complete WQEs that the PSN finishes.
 844          */
 845         while ((diff = ipath_cmp24(ack_psn, wqe->lpsn)) >= 0) {
 846                 /*
 847                  * RDMA_READ_RESPONSE_ONLY is a special case since
 848                  * we want to generate completion events for everything
 849                  * before the RDMA read, copy the data, then generate
 850                  * the completion for the read.
 851                  */
 852                 if (wqe->wr.opcode == IB_WR_RDMA_READ &&
 853                     opcode == OP(RDMA_READ_RESPONSE_ONLY) &&
 854                     diff == 0) {
 855                         ret = 1;
 856                         goto bail;
 857                 }
 858                 /*
 859                  * If this request is a RDMA read or atomic, and the ACK is
 860                  * for a later operation, this ACK NAKs the RDMA read or
 861                  * atomic.  In other words, only a RDMA_READ_LAST or ONLY
 862                  * can ACK a RDMA read and likewise for atomic ops.  Note
 863                  * that the NAK case can only happen if relaxed ordering is
 864                  * used and requests are sent after an RDMA read or atomic
 865                  * is sent but before the response is received.
 866                  */
 867                 if ((wqe->wr.opcode == IB_WR_RDMA_READ &&
 868                      (opcode != OP(RDMA_READ_RESPONSE_LAST) || diff != 0)) ||
 869                     ((wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
 870                       wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) &&
 871                      (opcode != OP(ATOMIC_ACKNOWLEDGE) || diff != 0))) {
 872                         /*
 873                          * The last valid PSN seen is the previous
 874                          * request's.
 875                          */
 876                         update_last_psn(qp, wqe->psn - 1);
 877                         /* Retry this request. */
 878                         ipath_restart_rc(qp, wqe->psn, &wc);
 879                         /*
 880                          * No need to process the ACK/NAK since we are
 881                          * restarting an earlier request.
 882                          */
 883                         goto bail;
 884                 }
 885                 if (wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
 886                     wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)
 887                         *(u64 *) wqe->sg_list[0].vaddr = val;
 888                 if (qp->s_num_rd_atomic &&
 889                     (wqe->wr.opcode == IB_WR_RDMA_READ ||
 890                      wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
 891                      wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)) {
 892                         qp->s_num_rd_atomic--;
 893                         /* Restart sending task if fence is complete */
 894                         if ((qp->s_flags & IPATH_S_FENCE_PENDING) &&
 895                             !qp->s_num_rd_atomic) {
 896                                 qp->s_flags &= ~IPATH_S_FENCE_PENDING;
 897                                 tasklet_hi_schedule(&qp->s_task);
 898                         } else if (qp->s_flags & IPATH_S_RDMAR_PENDING) {
 899                                 qp->s_flags &= ~IPATH_S_RDMAR_PENDING;
 900                                 tasklet_hi_schedule(&qp->s_task);
 901                         }
 902                 }
 903                 /* Post a send completion queue entry if requested. */
 904                 if (!(qp->s_flags & IPATH_S_SIGNAL_REQ_WR) ||
 905                     (wqe->wr.send_flags & IB_SEND_SIGNALED)) {
 906                         wc.wr_id = wqe->wr.wr_id;
 907                         wc.status = IB_WC_SUCCESS;
 908                         wc.opcode = ib_ipath_wc_opcode[wqe->wr.opcode];
 909                         wc.vendor_err = 0;
 910                         wc.byte_len = wqe->length;
 911                         wc.imm_data = 0;
 912                         wc.qp = &qp->ibqp;
 913                         wc.src_qp = qp->remote_qpn;
 914                         wc.wc_flags = 0;
 915                         wc.pkey_index = 0;
 916                         wc.slid = qp->remote_ah_attr.dlid;
 917                         wc.sl = qp->remote_ah_attr.sl;
 918                         wc.dlid_path_bits = 0;
 919                         wc.port_num = 0;
 920                         ipath_cq_enter(to_icq(qp->ibqp.send_cq), &wc, 0);
 921                 }
 922                 qp->s_retry = qp->s_retry_cnt;
 923                 /*
 924                  * If we are completing a request which is in the process of
 925                  * being resent, we can stop resending it since we know the
 926                  * responder has already seen it.
 927                  */
 928                 if (qp->s_last == qp->s_cur) {
 929                         if (++qp->s_cur >= qp->s_size)
 930                                 qp->s_cur = 0;
 931                         qp->s_last = qp->s_cur;
 932                         if (qp->s_last == qp->s_tail)
 933                                 break;
 934                         wqe = get_swqe_ptr(qp, qp->s_cur);
 935                         qp->s_state = OP(SEND_LAST);
 936                         qp->s_psn = wqe->psn;
 937                 } else {
 938                         if (++qp->s_last >= qp->s_size)
 939                                 qp->s_last = 0;
 940                         if (qp->s_last == qp->s_tail)
 941                                 break;
 942                         wqe = get_swqe_ptr(qp, qp->s_last);
 943                 }
 944         }
 945
 946         switch (aeth >> 29) {
 947         case 0:         /* ACK */
 948                 dev->n_rc_acks++;
 949                 /* If this is a partial ACK, reset the retransmit timer. */
 950                 if (qp->s_last != qp->s_tail) {
 951                         spin_lock(&dev->pending_lock);
 952                         list_add_tail(&qp->timerwait,
 953                                       &dev->pending[dev->pending_index]);
 954                         spin_unlock(&dev->pending_lock);
 955                         /*
 956                          * If we get a partial ACK for a resent operation,
 957                          * we can stop resending the earlier packets and
 958                          * continue with the next packet the receiver wants.
 959                          */
 960                         if (ipath_cmp24(qp->s_psn, psn) <= 0) {
 961                                 reset_psn(qp, psn + 1);
 962                                 tasklet_hi_schedule(&qp->s_task);
 963                         }
 964                 } else if (ipath_cmp24(qp->s_psn, psn) <= 0) {
 965                         qp->s_state = OP(SEND_LAST);
 966                         qp->s_psn = psn + 1;
 967                 }
 968                 ipath_get_credit(qp, aeth);
 969                 qp->s_rnr_retry = qp->s_rnr_retry_cnt;
 970                 qp->s_retry = qp->s_retry_cnt;
 971                 update_last_psn(qp, psn);
 972                 ret = 1;
 973                 goto bail;
 974
 975         case 1:         /* RNR NAK */
 976                 dev->n_rnr_naks++;
 977                 if (qp->s_last == qp->s_tail)
 978                         goto bail;
 979                 if (qp->s_rnr_retry == 0) {
 980                         wc.status = IB_WC_RNR_RETRY_EXC_ERR;
 981                         goto class_b;
 982                 }
 983                 if (qp->s_rnr_retry_cnt < 7)
 984                         qp->s_rnr_retry--;
 985
 986                 /* The last valid PSN is the previous PSN. */
 987                 update_last_psn(qp, psn - 1);
 988
 989                 if (wqe->wr.opcode == IB_WR_RDMA_READ)
 990                         dev->n_rc_resends++;
 991                 else
 992                         dev->n_rc_resends +=
 993                                 (qp->s_psn - psn) & IPATH_PSN_MASK;
 994
 995                 reset_psn(qp, psn);
 996
 997                 qp->s_rnr_timeout =
 998                         ib_ipath_rnr_table[(aeth >> IPATH_AETH_CREDIT_SHIFT) &
 999                                            IPATH_AETH_CREDIT_MASK];
1000                 ipath_insert_rnr_queue(qp);
1001                 goto bail;
1002
1003         case 3:         /* NAK */
1004                 if (qp->s_last == qp->s_tail)
1005                         goto bail;
1006                 /* The last valid PSN is the previous PSN. */
1007                 update_last_psn(qp, psn - 1);
1008                 switch ((aeth >> IPATH_AETH_CREDIT_SHIFT) &
1009                         IPATH_AETH_CREDIT_MASK) {
1010                 case 0: /* PSN sequence error */
1011                         dev->n_seq_naks++;
1012                         /*
1013                          * Back up to the responder's expected PSN.
1014                          * Note that we might get a NAK in the middle of an
1015                          * RDMA READ response which terminates the RDMA
1016                          * READ.
1017                          */
1018                         ipath_restart_rc(qp, psn, &wc);
1019                         break;
1020
1021                 case 1: /* Invalid Request */
1022                         wc.status = IB_WC_REM_INV_REQ_ERR;
1023                         dev->n_other_naks++;
1024                         goto class_b;
1025
1026                 case 2: /* Remote Access Error */
1027                         wc.status = IB_WC_REM_ACCESS_ERR;
1028                         dev->n_other_naks++;
1029                         goto class_b;
1030
1031                 case 3: /* Remote Operation Error */
1032                         wc.status = IB_WC_REM_OP_ERR;
1033                         dev->n_other_naks++;
1034                 class_b:
1035                         wc.wr_id = wqe->wr.wr_id;
1036                         wc.opcode = ib_ipath_wc_opcode[wqe->wr.opcode];
1037                         wc.vendor_err = 0;
1038                         wc.byte_len = 0;
1039                         wc.qp = &qp->ibqp;
1040                         wc.src_qp = qp->remote_qpn;
1041                         wc.pkey_index = 0;
1042                         wc.slid = qp->remote_ah_attr.dlid;
1043                         wc.sl = qp->remote_ah_attr.sl;
1044                         wc.dlid_path_bits = 0;
1045                         wc.port_num = 0;
1046                         ipath_sqerror_qp(qp, &wc);
1047                         break;
1048
1049                 default:
1050                         /* Ignore other reserved NAK error codes */
1051                         goto reserved;
1052                 }
1053                 qp->s_rnr_retry = qp->s_rnr_retry_cnt;
1054                 goto bail;
1055
1056         default:                /* 2: reserved */
1057         reserved:
1058                 /* Ignore reserved NAK codes. */
1059                 goto bail;
1060         }
1061
1062 bail:
1063         return ret;
1064 }
1065
1066 /**
1067  * ipath_rc_rcv_resp - process an incoming RC response packet
1068  * @dev: the device this packet came in on
1069  * @ohdr: the other headers for this packet
1070  * @data: the packet data
1071  * @tlen: the packet length
1072  * @qp: the QP for this packet
1073  * @opcode: the opcode for this packet
1074  * @psn: the packet sequence number for this packet
1075  * @hdrsize: the header length
1076  * @pmtu: the path MTU
1077  * @header_in_data: true if part of the header data is in the data buffer
1078  *
1079  * This is called from ipath_rc_rcv() to process an incoming RC response
1080  * packet for the given QP.
1081  * Called at interrupt level.
1082  */
1083 static inline void ipath_rc_rcv_resp(struct ipath_ibdev *dev,
1084                                      struct ipath_other_headers *ohdr,
1085                                      void *data, u32 tlen,
1086                                      struct ipath_qp *qp,
1087                                      u32 opcode,
1088                                      u32 psn, u32 hdrsize, u32 pmtu,
1089                                      int header_in_data)
1090 {
1091         struct ipath_swqe *wqe;
1092         unsigned long flags;
1093         struct ib_wc wc;
1094         int diff;
1095         u32 pad;
1096         u32 aeth;
1097         u64 val;
1098
1099         spin_lock_irqsave(&qp->s_lock, flags);
1100
1101         /* Ignore invalid responses. */
1102         if (ipath_cmp24(psn, qp->s_next_psn) >= 0)
1103                 goto ack_done;
1104
1105         /* Ignore duplicate responses. */
1106         diff = ipath_cmp24(psn, qp->s_last_psn);
1107         if (unlikely(diff <= 0)) {
1108                 /* Update credits for "ghost" ACKs */
1109                 if (diff == 0 && opcode == OP(ACKNOWLEDGE)) {
1110                         if (!header_in_data)
1111                                 aeth = be32_to_cpu(ohdr->u.aeth);
1112                         else {
1113                                 aeth = be32_to_cpu(((__be32 *) data)[0]);
1114                                 data += sizeof(__be32);
1115                         }
1116                         if ((aeth >> 29) == 0)
1117                                 ipath_get_credit(qp, aeth);
1118                 }
1119                 goto ack_done;
1120         }
1121
1122         if (unlikely(qp->s_last == qp->s_tail))
1123                 goto ack_done;
1124         wqe = get_swqe_ptr(qp, qp->s_last);
1125
1126         switch (opcode) {
1127         case OP(ACKNOWLEDGE):
1128         case OP(ATOMIC_ACKNOWLEDGE):
1129         case OP(RDMA_READ_RESPONSE_FIRST):
1130                 if (!header_in_data)
1131                         aeth = be32_to_cpu(ohdr->u.aeth);
1132                 else {
1133                         aeth = be32_to_cpu(((__be32 *) data)[0]);
1134                         data += sizeof(__be32);
1135                 }
1136                 if (opcode == OP(ATOMIC_ACKNOWLEDGE)) {
1137                         if (!header_in_data) {
1138                                 __be32 *p = ohdr->u.at.atomic_ack_eth;
1139
1140                                 val = ((u64) be32_to_cpu(p[0]) << 32) |
1141                                         be32_to_cpu(p[1]);
1142                         } else
1143                                 val = be64_to_cpu(((__be64 *) data)[0]);
1144                 } else
1145                         val = 0;
1146                 if (!do_rc_ack(qp, aeth, psn, opcode, val) ||
1147                     opcode != OP(RDMA_READ_RESPONSE_FIRST))
1148                         goto ack_done;
1149                 hdrsize += 4;
1150                 wqe = get_swqe_ptr(qp, qp->s_last);
1151                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1152                         goto ack_op_err;
1153                 /*
1154                  * If this is a response to a resent RDMA read, we
1155                  * have to be careful to copy the data to the right
1156                  * location.
1157                  */
1158                 qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
1159                                                   wqe, psn, pmtu);
1160                 goto read_middle;
1161
1162         case OP(RDMA_READ_RESPONSE_MIDDLE):
1163                 /* no AETH, no ACK */
1164                 if (unlikely(ipath_cmp24(psn, qp->s_last_psn + 1))) {
1165                         dev->n_rdma_seq++;
1166                         ipath_restart_rc(qp, qp->s_last_psn + 1, &wc);
1167                         goto ack_done;
1168                 }
1169                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1170                         goto ack_op_err;
1171         read_middle:
1172                 if (unlikely(tlen != (hdrsize + pmtu + 4)))
1173                         goto ack_len_err;
1174                 if (unlikely(pmtu >= qp->s_rdma_read_len))
1175                         goto ack_len_err;
1176
1177                 /* We got a response so update the timeout. */
1178                 spin_lock(&dev->pending_lock);
1179                 if (qp->s_rnr_timeout == 0 && !list_empty(&qp->timerwait))
1180                         list_move_tail(&qp->timerwait,
1181                                        &dev->pending[dev->pending_index]);
1182                 spin_unlock(&dev->pending_lock);
1183                 /*
1184                  * Update the RDMA receive state but do the copy w/o
1185                  * holding the locks and blocking interrupts.
1186                  */
1187                 qp->s_rdma_read_len -= pmtu;
1188                 update_last_psn(qp, psn);
1189                 spin_unlock_irqrestore(&qp->s_lock, flags);
1190                 ipath_copy_sge(&qp->s_rdma_read_sge, data, pmtu);
1191                 goto bail;
1192
1193         case OP(RDMA_READ_RESPONSE_ONLY):
1194                 if (!header_in_data)
1195                         aeth = be32_to_cpu(ohdr->u.aeth);
1196                 else
1197                         aeth = be32_to_cpu(((__be32 *) data)[0]);
1198                 if (!do_rc_ack(qp, aeth, psn, opcode, 0))
1199                         goto ack_done;
1200                 /* Get the number of bytes the message was padded by. */
1201                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1202                 /*
1203                  * Check that the data size is >= 0 && <= pmtu.
1204                  * Remember to account for the AETH header (4) and
1205                  * ICRC (4).
1206                  */
1207                 if (unlikely(tlen < (hdrsize + pad + 8)))
1208                         goto ack_len_err;
1209                 /*
1210                  * If this is a response to a resent RDMA read, we
1211                  * have to be careful to copy the data to the right
1212                  * location.
1213                  */
1214                 wqe = get_swqe_ptr(qp, qp->s_last);
1215                 qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
1216                                                   wqe, psn, pmtu);
1217                 goto read_last;
1218
1219         case OP(RDMA_READ_RESPONSE_LAST):
1220                 /* ACKs READ req. */
1221                 if (unlikely(ipath_cmp24(psn, qp->s_last_psn + 1))) {
1222                         dev->n_rdma_seq++;
1223                         ipath_restart_rc(qp, qp->s_last_psn + 1, &wc);
1224                         goto ack_done;
1225                 }
1226                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1227                         goto ack_op_err;
1228                 /* Get the number of bytes the message was padded by. */
1229                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1230                 /*
1231                  * Check that the data size is >= 1 && <= pmtu.
1232                  * Remember to account for the AETH header (4) and
1233                  * ICRC (4).
1234                  */
1235                 if (unlikely(tlen <= (hdrsize + pad + 8)))
1236                         goto ack_len_err;
1237         read_last:
1238                 tlen -= hdrsize + pad + 8;
1239                 if (unlikely(tlen != qp->s_rdma_read_len))
1240                         goto ack_len_err;
1241                 if (!header_in_data)
1242                         aeth = be32_to_cpu(ohdr->u.aeth);
1243                 else {
1244                         aeth = be32_to_cpu(((__be32 *) data)[0]);
1245                         data += sizeof(__be32);
1246                 }
1247                 ipath_copy_sge(&qp->s_rdma_read_sge, data, tlen);
1248                 (void) do_rc_ack(qp, aeth, psn,
1249                                  OP(RDMA_READ_RESPONSE_LAST), 0);
1250                 goto ack_done;
1251         }
1252
1253 ack_done:
1254         spin_unlock_irqrestore(&qp->s_lock, flags);
1255         goto bail;
1256
1257 ack_op_err:
1258         wc.status = IB_WC_LOC_QP_OP_ERR;
1259         goto ack_err;
1260
1261 ack_len_err:
1262         wc.status = IB_WC_LOC_LEN_ERR;
1263 ack_err:
1264         wc.wr_id = wqe->wr.wr_id;
1265         wc.opcode = ib_ipath_wc_opcode[wqe->wr.opcode];
1266         wc.vendor_err = 0;
1267         wc.byte_len = 0;
1268         wc.imm_data = 0;
1269         wc.qp = &qp->ibqp;
1270         wc.src_qp = qp->remote_qpn;
1271         wc.wc_flags = 0;
1272         wc.pkey_index = 0;
1273         wc.slid = qp->remote_ah_attr.dlid;
1274         wc.sl = qp->remote_ah_attr.sl;
1275         wc.dlid_path_bits = 0;
1276         wc.port_num = 0;
1277         ipath_sqerror_qp(qp, &wc);
1278         spin_unlock_irqrestore(&qp->s_lock, flags);
1279 bail:
1280         return;
1281 }
1282
1283 /**
1284  * ipath_rc_rcv_error - process an incoming duplicate or error RC packet
1285  * @dev: the device this packet came in on
1286  * @ohdr: the other headers for this packet
1287  * @data: the packet data
1288  * @qp: the QP for this packet
1289  * @opcode: the opcode for this packet
1290  * @psn: the packet sequence number for this packet
1291  * @diff: the difference between the PSN and the expected PSN
1292  * @header_in_data: true if part of the header data is in the data buffer
1293  *
1294  * This is called from ipath_rc_rcv() to process an unexpected
1295  * incoming RC packet for the given QP.
1296  * Called at interrupt level.
1297  * Return 1 if no more processing is needed; otherwise return 0 to
1298  * schedule a response to be sent.
1299  */
1300 static inline int ipath_rc_rcv_error(struct ipath_ibdev *dev,
1301                                      struct ipath_other_headers *ohdr,
1302                                      void *data,
1303                                      struct ipath_qp *qp,
1304                                      u32 opcode,
1305                                      u32 psn,
1306                                      int diff,
1307                                      int header_in_data)
1308 {
1309         struct ipath_ack_entry *e;
1310         u8 i, prev;
1311         int old_req;
1312         unsigned long flags;
1313
1314         if (diff > 0) {
1315                 /*
1316                  * Packet sequence error.
1317                  * A NAK will ACK earlier sends and RDMA writes.
1318                  * Don't queue the NAK if we already sent one.
1319                  */
1320                 if (!qp->r_nak_state) {
1321                         qp->r_nak_state = IB_NAK_PSN_ERROR;
1322                         /* Use the expected PSN. */
1323                         qp->r_ack_psn = qp->r_psn;
1324                         goto send_ack;
1325                 }
1326                 goto done;
1327         }
1328
1329         /*
1330          * Handle a duplicate request.  Don't re-execute SEND, RDMA
1331          * write or atomic op.  Don't NAK errors, just silently drop
1332          * the duplicate request.  Note that r_sge, r_len, and
1333          * r_rcv_len may be in use so don't modify them.
1334          *
1335          * We are supposed to ACK the earliest duplicate PSN but we
1336          * can coalesce an outstanding duplicate ACK.  We have to
1337          * send the earliest so that RDMA reads can be restarted at
1338          * the requester's expected PSN.
1339          *
1340          * First, find where this duplicate PSN falls within the
1341          * ACKs previously sent.
1342          */
1343         psn &= IPATH_PSN_MASK;
1344         e = NULL;
1345         old_req = 1;
1346         spin_lock_irqsave(&qp->s_lock, flags);
1347         for (i = qp->r_head_ack_queue; ; i = prev) {
1348                 if (i == qp->s_tail_ack_queue)
1349                         old_req = 0;
1350                 if (i)
1351                         prev = i - 1;
1352                 else
1353                         prev = IPATH_MAX_RDMA_ATOMIC;
1354                 if (prev == qp->r_head_ack_queue) {
1355                         e = NULL;
1356                         break;
1357                 }
1358                 e = &qp->s_ack_queue[prev];
1359                 if (!e->opcode) {
1360                         e = NULL;
1361                         break;
1362                 }
1363                 if (ipath_cmp24(psn, e->psn) >= 0) {
1364                         if (prev == qp->s_tail_ack_queue)
1365                                 old_req = 0;
1366                         break;
1367                 }
1368         }
1369         switch (opcode) {
1370         case OP(RDMA_READ_REQUEST): {
1371                 struct ib_reth *reth;
1372                 u32 offset;
1373                 u32 len;
1374
1375                 /*
1376                  * If we didn't find the RDMA read request in the ack queue,
1377                  * or the send tasklet is already backed up to send an
1378                  * earlier entry, we can ignore this request.
1379                  */
1380                 if (!e || e->opcode != OP(RDMA_READ_REQUEST) || old_req)
1381                         goto unlock_done;
1382                 /* RETH comes after BTH */
1383                 if (!header_in_data)
1384                         reth = &ohdr->u.rc.reth;
1385                 else {
1386                         reth = (struct ib_reth *)data;
1387                         data += sizeof(*reth);
1388                 }
1389                 /*
1390                  * Address range must be a subset of the original
1391                  * request and start on pmtu boundaries.
1392                  * We reuse the old ack_queue slot since the requester
1393                  * should not back up and request an earlier PSN for the
1394                  * same request.
1395                  */
1396                 offset = ((psn - e->psn) & IPATH_PSN_MASK) *
1397                         ib_mtu_enum_to_int(qp->path_mtu);
1398                 len = be32_to_cpu(reth->length);
1399                 if (unlikely(offset + len > e->rdma_sge.sge.sge_length))
1400                         goto unlock_done;
1401                 if (len != 0) {
1402                         u32 rkey = be32_to_cpu(reth->rkey);
1403                         u64 vaddr = be64_to_cpu(reth->vaddr);
1404                         int ok;
1405
1406                         ok = ipath_rkey_ok(qp, &e->rdma_sge,
1407                                            len, vaddr, rkey,
1408                                            IB_ACCESS_REMOTE_READ);
1409                         if (unlikely(!ok))
1410                                 goto unlock_done;
1411                 } else {
1412                         e->rdma_sge.sg_list = NULL;
1413                         e->rdma_sge.num_sge = 0;
1414                         e->rdma_sge.sge.mr = NULL;
1415                         e->rdma_sge.sge.vaddr = NULL;
1416                         e->rdma_sge.sge.length = 0;
1417                         e->rdma_sge.sge.sge_length = 0;
1418                 }
1419                 e->psn = psn;
1420                 qp->s_ack_state = OP(ACKNOWLEDGE);
1421                 qp->s_tail_ack_queue = prev;
1422                 break;
1423         }
1424
1425         case OP(COMPARE_SWAP):
1426         case OP(FETCH_ADD): {
1427                 /*
1428                  * If we didn't find the atomic request in the ack queue
1429                  * or the send tasklet is already backed up to send an
1430                  * earlier entry, we can ignore this request.
1431                  */
1432                 if (!e || e->opcode != (u8) opcode || old_req)
1433                         goto unlock_done;
1434                 qp->s_ack_state = OP(ACKNOWLEDGE);
1435                 qp->s_tail_ack_queue = prev;
1436                 break;
1437         }
1438
1439         default:
1440                 if (old_req)
1441                         goto unlock_done;
1442                 /*
1443                  * Resend the most recent ACK if this request is
1444                  * after all the previous RDMA reads and atomics.
1445                  */
1446                 if (i == qp->r_head_ack_queue) {
1447                         spin_unlock_irqrestore(&qp->s_lock, flags);
1448                         qp->r_nak_state = 0;
1449                         qp->r_ack_psn = qp->r_psn - 1;
1450                         goto send_ack;
1451                 }
1452                 /*
1453                  * Resend the RDMA read or atomic op which
1454                  * ACKs this duplicate request.
1455                  */
1456                 qp->s_ack_state = OP(ACKNOWLEDGE);
1457                 qp->s_tail_ack_queue = i;
1458                 break;
1459         }
1460         qp->r_nak_state = 0;
1461         tasklet_hi_schedule(&qp->s_task);
1462
1463 unlock_done:
1464         spin_unlock_irqrestore(&qp->s_lock, flags);
1465 done:
1466         return 1;
1467
1468 send_ack:
1469         return 0;
1470 }
1471
1472 static void ipath_rc_error(struct ipath_qp *qp, enum ib_wc_status err)
1473 {
1474         unsigned long flags;
1475
1476         spin_lock_irqsave(&qp->s_lock, flags);
1477         qp->state = IB_QPS_ERR;
1478         ipath_error_qp(qp, err);
1479         spin_unlock_irqrestore(&qp->s_lock, flags);
1480 }
1481
1482 /**
1483  * ipath_rc_rcv - process an incoming RC packet
1484  * @dev: the device this packet came in on
1485  * @hdr: the header of this packet
1486  * @has_grh: true if the header has a GRH
1487  * @data: the packet data
1488  * @tlen: the packet length
1489  * @qp: the QP for this packet
1490  *
1491  * This is called from ipath_qp_rcv() to process an incoming RC packet
1492  * for the given QP.
1493  * Called at interrupt level.
1494  */
1495 void ipath_rc_rcv(struct ipath_ibdev *dev, struct ipath_ib_header *hdr,
1496                   int has_grh, void *data, u32 tlen, struct ipath_qp *qp)
1497 {
1498         struct ipath_other_headers *ohdr;
1499         u32 opcode;
1500         u32 hdrsize;
1501         u32 psn;
1502         u32 pad;
1503         struct ib_wc wc;
1504         u32 pmtu = ib_mtu_enum_to_int(qp->path_mtu);
1505         int diff;
1506         struct ib_reth *reth;
1507         int header_in_data;
1508
1509         /* Validate the SLID. See Ch. 9.6.1.5 */
1510         if (unlikely(be16_to_cpu(hdr->lrh[3]) != qp->remote_ah_attr.dlid))
1511                 goto done;
1512
1513         /* Check for GRH */
1514         if (!has_grh) {
1515                 ohdr = &hdr->u.oth;
1516                 hdrsize = 8 + 12;       /* LRH + BTH */
1517                 psn = be32_to_cpu(ohdr->bth[2]);
1518                 header_in_data = 0;
1519         } else {
1520                 ohdr = &hdr->u.l.oth;
1521                 hdrsize = 8 + 40 + 12;  /* LRH + GRH + BTH */
1522                 /*
1523                  * The header with GRH is 60 bytes and the core driver sets
1524                  * the eager header buffer size to 56 bytes so the last 4
1525                  * bytes of the BTH header (PSN) is in the data buffer.
1526                  */
1527                 header_in_data = dev->dd->ipath_rcvhdrentsize == 16;
1528                 if (header_in_data) {
1529                         psn = be32_to_cpu(((__be32 *) data)[0]);
1530                         data += sizeof(__be32);
1531                 } else
1532                         psn = be32_to_cpu(ohdr->bth[2]);
1533         }
1534
1535         /*
1536          * Process responses (ACKs) before anything else.  Note that the
1537          * packet sequence number will be for something in the send work
1538          * queue rather than the expected receive packet sequence number.
1539          * In other words, this QP is the requester.
1540          */
1541         opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
1542         if (opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
1543             opcode <= OP(ATOMIC_ACKNOWLEDGE)) {
1544                 ipath_rc_rcv_resp(dev, ohdr, data, tlen, qp, opcode, psn,
1545                                   hdrsize, pmtu, header_in_data);
1546                 goto done;
1547         }
1548
1549         /* Compute 24 bits worth of difference. */
1550         diff = ipath_cmp24(psn, qp->r_psn);
1551         if (unlikely(diff)) {
1552                 if (ipath_rc_rcv_error(dev, ohdr, data, qp, opcode,
1553                                        psn, diff, header_in_data))
1554                         goto done;
1555                 goto send_ack;
1556         }
1557
1558         /* Check for opcode sequence errors. */
1559         switch (qp->r_state) {
1560         case OP(SEND_FIRST):
1561         case OP(SEND_MIDDLE):
1562                 if (opcode == OP(SEND_MIDDLE) ||
1563                     opcode == OP(SEND_LAST) ||
1564                     opcode == OP(SEND_LAST_WITH_IMMEDIATE))
1565                         break;
1566         nack_inv:
1567                 ipath_rc_error(qp, IB_WC_REM_INV_REQ_ERR);
1568                 qp->r_nak_state = IB_NAK_INVALID_REQUEST;
1569                 qp->r_ack_psn = qp->r_psn;
1570                 goto send_ack;
1571
1572         case OP(RDMA_WRITE_FIRST):
1573         case OP(RDMA_WRITE_MIDDLE):
1574                 if (opcode == OP(RDMA_WRITE_MIDDLE) ||
1575                     opcode == OP(RDMA_WRITE_LAST) ||
1576                     opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
1577                         break;
1578                 goto nack_inv;
1579
1580         default:
1581                 if (opcode == OP(SEND_MIDDLE) ||
1582                     opcode == OP(SEND_LAST) ||
1583                     opcode == OP(SEND_LAST_WITH_IMMEDIATE) ||
1584                     opcode == OP(RDMA_WRITE_MIDDLE) ||
1585                     opcode == OP(RDMA_WRITE_LAST) ||
1586                     opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
1587                         goto nack_inv;
1588                 /*
1589                  * Note that it is up to the requester to not send a new
1590                  * RDMA read or atomic operation before receiving an ACK
1591                  * for the previous operation.
1592                  */
1593                 break;
1594         }
1595
1596         wc.imm_data = 0;
1597         wc.wc_flags = 0;
1598
1599         /* OK, process the packet. */
1600         switch (opcode) {
1601         case OP(SEND_FIRST):
1602                 if (!ipath_get_rwqe(qp, 0)) {
1603                 rnr_nak:
1604                         /*
1605                          * A RNR NAK will ACK earlier sends and RDMA writes.
1606                          * Don't queue the NAK if a RDMA read or atomic
1607                          * is pending though.
1608                          */
1609                         if (qp->r_nak_state)
1610                                 goto done;
1611                         qp->r_nak_state = IB_RNR_NAK | qp->r_min_rnr_timer;
1612                         qp->r_ack_psn = qp->r_psn;
1613                         goto send_ack;
1614                 }
1615                 qp->r_rcv_len = 0;
1616                 /* FALLTHROUGH */
1617         case OP(SEND_MIDDLE):
1618         case OP(RDMA_WRITE_MIDDLE):
1619         send_middle:
1620                 /* Check for invalid length PMTU or posted rwqe len. */
1621                 if (unlikely(tlen != (hdrsize + pmtu + 4)))
1622                         goto nack_inv;
1623                 qp->r_rcv_len += pmtu;
1624                 if (unlikely(qp->r_rcv_len > qp->r_len))
1625                         goto nack_inv;
1626                 ipath_copy_sge(&qp->r_sge, data, pmtu);
1627                 break;
1628
1629         case OP(RDMA_WRITE_LAST_WITH_IMMEDIATE):
1630                 /* consume RWQE */
1631                 if (!ipath_get_rwqe(qp, 1))
1632                         goto rnr_nak;
1633                 goto send_last_imm;
1634
1635         case OP(SEND_ONLY):
1636         case OP(SEND_ONLY_WITH_IMMEDIATE):
1637                 if (!ipath_get_rwqe(qp, 0))
1638                         goto rnr_nak;
1639                 qp->r_rcv_len = 0;
1640                 if (opcode == OP(SEND_ONLY))
1641                         goto send_last;
1642                 /* FALLTHROUGH */
1643         case OP(SEND_LAST_WITH_IMMEDIATE):
1644         send_last_imm:
1645                 if (header_in_data) {
1646                         wc.imm_data = *(__be32 *) data;
1647                         data += sizeof(__be32);
1648                 } else {
1649                         /* Immediate data comes after BTH */
1650                         wc.imm_data = ohdr->u.imm_data;
1651                 }
1652                 hdrsize += 4;
1653                 wc.wc_flags = IB_WC_WITH_IMM;
1654                 /* FALLTHROUGH */
1655         case OP(SEND_LAST):
1656         case OP(RDMA_WRITE_LAST):
1657         send_last:
1658                 /* Get the number of bytes the message was padded by. */
1659                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1660                 /* Check for invalid length. */
1661                 /* XXX LAST len should be >= 1 */
1662                 if (unlikely(tlen < (hdrsize + pad + 4)))
1663                         goto nack_inv;
1664                 /* Don't count the CRC. */
1665                 tlen -= (hdrsize + pad + 4);
1666                 wc.byte_len = tlen + qp->r_rcv_len;
1667                 if (unlikely(wc.byte_len > qp->r_len))
1668                         goto nack_inv;
1669                 ipath_copy_sge(&qp->r_sge, data, tlen);
1670                 qp->r_msn++;
1671                 if (!qp->r_wrid_valid)
1672                         break;
1673                 qp->r_wrid_valid = 0;
1674                 wc.wr_id = qp->r_wr_id;
1675                 wc.status = IB_WC_SUCCESS;
1676                 wc.opcode = IB_WC_RECV;
1677                 wc.vendor_err = 0;
1678                 wc.qp = &qp->ibqp;
1679                 wc.src_qp = qp->remote_qpn;
1680                 wc.pkey_index = 0;
1681                 wc.slid = qp->remote_ah_attr.dlid;
1682                 wc.sl = qp->remote_ah_attr.sl;
1683                 wc.dlid_path_bits = 0;
1684                 wc.port_num = 0;
1685                 /* Signal completion event if the solicited bit is set. */
1686                 ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
1687                                (ohdr->bth[0] &
1688                                 __constant_cpu_to_be32(1 << 23)) != 0);
1689                 break;
1690
1691         case OP(RDMA_WRITE_FIRST):
1692         case OP(RDMA_WRITE_ONLY):
1693         case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE):
1694                 /* consume RWQE */
1695                 /* RETH comes after BTH */
1696                 if (!header_in_data)
1697                         reth = &ohdr->u.rc.reth;
1698                 else {
1699                         reth = (struct ib_reth *)data;
1700                         data += sizeof(*reth);
1701                 }
1702                 hdrsize += sizeof(*reth);
1703                 qp->r_len = be32_to_cpu(reth->length);
1704                 qp->r_rcv_len = 0;
1705                 if (qp->r_len != 0) {
1706                         u32 rkey = be32_to_cpu(reth->rkey);
1707                         u64 vaddr = be64_to_cpu(reth->vaddr);
1708                         int ok;
1709
1710                         /* Check rkey & NAK */
1711                         ok = ipath_rkey_ok(qp, &qp->r_sge,
1712                                            qp->r_len, vaddr, rkey,
1713                                            IB_ACCESS_REMOTE_WRITE);
1714                         if (unlikely(!ok))
1715                                 goto nack_acc;
1716                 } else {
1717                         qp->r_sge.sg_list = NULL;
1718                         qp->r_sge.sge.mr = NULL;
1719                         qp->r_sge.sge.vaddr = NULL;
1720                         qp->r_sge.sge.length = 0;
1721                         qp->r_sge.sge.sge_length = 0;
1722                 }
1723                 if (unlikely(!(qp->qp_access_flags &
1724                                IB_ACCESS_REMOTE_WRITE)))
1725                         goto nack_acc;
1726                 if (opcode == OP(RDMA_WRITE_FIRST))
1727                         goto send_middle;
1728                 else if (opcode == OP(RDMA_WRITE_ONLY))
1729                         goto send_last;
1730                 if (!ipath_get_rwqe(qp, 1))
1731                         goto rnr_nak;
1732                 goto send_last_imm;
1733
1734         case OP(RDMA_READ_REQUEST): {
1735                 struct ipath_ack_entry *e;
1736                 u32 len;
1737                 u8 next;
1738
1739                 if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_READ)))
1740                         goto nack_acc;
1741                 next = qp->r_head_ack_queue + 1;
1742                 if (next > IPATH_MAX_RDMA_ATOMIC)
1743                         next = 0;
1744                 if (unlikely(next == qp->s_tail_ack_queue))
1745                         goto nack_inv;
1746                 e = &qp->s_ack_queue[qp->r_head_ack_queue];
1747                 /* RETH comes after BTH */
1748                 if (!header_in_data)
1749                         reth = &ohdr->u.rc.reth;
1750                 else {
1751                         reth = (struct ib_reth *)data;
1752                         data += sizeof(*reth);
1753                 }
1754                 len = be32_to_cpu(reth->length);
1755                 if (len) {
1756                         u32 rkey = be32_to_cpu(reth->rkey);
1757                         u64 vaddr = be64_to_cpu(reth->vaddr);
1758                         int ok;
1759
1760                         /* Check rkey & NAK */
1761                         ok = ipath_rkey_ok(qp, &e->rdma_sge, len, vaddr,
1762                                            rkey, IB_ACCESS_REMOTE_READ);
1763                         if (unlikely(!ok))
1764                                 goto nack_acc;
1765                         /*
1766                          * Update the next expected PSN.  We add 1 later
1767                          * below, so only add the remainder here.
1768                          */
1769                         if (len > pmtu)
1770                                 qp->r_psn += (len - 1) / pmtu;
1771                 } else {
1772                         e->rdma_sge.sg_list = NULL;
1773                         e->rdma_sge.num_sge = 0;
1774                         e->rdma_sge.sge.mr = NULL;
1775                         e->rdma_sge.sge.vaddr = NULL;
1776                         e->rdma_sge.sge.length = 0;
1777                         e->rdma_sge.sge.sge_length = 0;
1778                 }
1779                 e->opcode = opcode;
1780                 e->psn = psn;
1781                 /*
1782                  * We need to increment the MSN here instead of when we
1783                  * finish sending the result since a duplicate request would
1784                  * increment it more than once.
1785                  */
1786                 qp->r_msn++;
1787                 qp->r_psn++;
1788                 qp->r_state = opcode;
1789                 qp->r_nak_state = 0;
1790                 barrier();
1791                 qp->r_head_ack_queue = next;
1792
1793                 /* Call ipath_do_rc_send() in another thread. */
1794                 tasklet_hi_schedule(&qp->s_task);
1795
1796                 goto done;
1797         }
1798
1799         case OP(COMPARE_SWAP):
1800         case OP(FETCH_ADD): {
1801                 struct ib_atomic_eth *ateth;
1802                 struct ipath_ack_entry *e;
1803                 u64 vaddr;
1804                 atomic64_t *maddr;
1805                 u64 sdata;
1806                 u32 rkey;
1807                 u8 next;
1808
1809                 if (unlikely(!(qp->qp_access_flags &
1810                                IB_ACCESS_REMOTE_ATOMIC)))
1811                         goto nack_acc;
1812                 next = qp->r_head_ack_queue + 1;
1813                 if (next > IPATH_MAX_RDMA_ATOMIC)
1814                         next = 0;
1815                 if (unlikely(next == qp->s_tail_ack_queue))
1816                         goto nack_inv;
1817                 if (!header_in_data)
1818                         ateth = &ohdr->u.atomic_eth;
1819                 else
1820                         ateth = (struct ib_atomic_eth *)data;
1821                 vaddr = ((u64) be32_to_cpu(ateth->vaddr[0]) << 32) |
1822                         be32_to_cpu(ateth->vaddr[1]);
1823                 if (unlikely(vaddr & (sizeof(u64) - 1)))
1824                         goto nack_inv;
1825                 rkey = be32_to_cpu(ateth->rkey);
1826                 /* Check rkey & NAK */
1827                 if (unlikely(!ipath_rkey_ok(qp, &qp->r_sge,
1828                                             sizeof(u64), vaddr, rkey,
1829                                             IB_ACCESS_REMOTE_ATOMIC)))
1830                         goto nack_acc;
1831                 /* Perform atomic OP and save result. */
1832                 maddr = (atomic64_t *) qp->r_sge.sge.vaddr;
1833                 sdata = be64_to_cpu(ateth->swap_data);
1834                 e = &qp->s_ack_queue[qp->r_head_ack_queue];
1835                 e->atomic_data = (opcode == OP(FETCH_ADD)) ?
1836                         (u64) atomic64_add_return(sdata, maddr) - sdata :
1837                         (u64) cmpxchg((u64 *) qp->r_sge.sge.vaddr,
1838                                       be64_to_cpu(ateth->compare_data),
1839                                       sdata);
1840                 e->opcode = opcode;
1841                 e->psn = psn & IPATH_PSN_MASK;
1842                 qp->r_msn++;
1843                 qp->r_psn++;
1844                 qp->r_state = opcode;
1845                 qp->r_nak_state = 0;
1846                 barrier();
1847                 qp->r_head_ack_queue = next;
1848
1849                 /* Call ipath_do_rc_send() in another thread. */
1850                 tasklet_hi_schedule(&qp->s_task);
1851
1852                 goto done;
1853         }
1854
1855         default:
1856                 /* NAK unknown opcodes. */
1857                 goto nack_inv;
1858         }
1859         qp->r_psn++;
1860         qp->r_state = opcode;
1861         qp->r_ack_psn = psn;
1862         qp->r_nak_state = 0;
1863         /* Send an ACK if requested or required. */
1864         if (psn & (1 << 31))
1865                 goto send_ack;
1866         goto done;
1867
1868 nack_acc:
1869         ipath_rc_error(qp, IB_WC_REM_ACCESS_ERR);
1870         qp->r_nak_state = IB_NAK_REMOTE_ACCESS_ERROR;
1871         qp->r_ack_psn = qp->r_psn;
1872
1873 send_ack:
1874         send_rc_ack(qp);
1875
1876 done:
1877         return;
1878 }