git.oblomov.eu Git - linux-2.6/blob - 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;
 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 = 0;
 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;
 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 {
 811         struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
 812         struct ib_wc wc;
 813         struct ipath_swqe *wqe;
 814         int ret = 0;
 815         u32 ack_psn;
 816
 817         /*
 818          * Remove the QP from the timeout queue (or RNR timeout queue).
 819          * If ipath_ib_timer() has already removed it,
 820          * it's OK since we hold the QP s_lock and ipath_restart_rc()
 821          * just won't find anything to restart if we ACK everything.
 822          */
 823         spin_lock(&dev->pending_lock);
 824         if (!list_empty(&qp->timerwait))
 825                 list_del_init(&qp->timerwait);
 826         spin_unlock(&dev->pending_lock);
 827
 828         /*
 829          * Note that NAKs implicitly ACK outstanding SEND and RDMA write
 830          * requests and implicitly NAK RDMA read and atomic requests issued
 831          * before the NAK'ed request.  The MSN won't include the NAK'ed
 832          * request but will include an ACK'ed request(s).
 833          */
 834         ack_psn = psn;
 835         if (aeth >> 29)
 836                 ack_psn--;
 837         wqe = get_swqe_ptr(qp, qp->s_last);
 838
 839         /*
 840          * The MSN might be for a later WQE than the PSN indicates so
 841          * only complete WQEs that the PSN finishes.
 842          */
 843         while (ipath_cmp24(ack_psn, wqe->lpsn) >= 0) {
 844                 /*
 845                  * If this request is a RDMA read or atomic, and the ACK is
 846                  * for a later operation, this ACK NAKs the RDMA read or
 847                  * atomic.  In other words, only a RDMA_READ_LAST or ONLY
 848                  * can ACK a RDMA read and likewise for atomic ops.  Note
 849                  * that the NAK case can only happen if relaxed ordering is
 850                  * used and requests are sent after an RDMA read or atomic
 851                  * is sent but before the response is received.
 852                  */
 853                 if ((wqe->wr.opcode == IB_WR_RDMA_READ &&
 854                      (opcode != OP(RDMA_READ_RESPONSE_LAST) ||
 855                       ipath_cmp24(ack_psn, wqe->lpsn) != 0)) ||
 856                     ((wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
 857                       wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) &&
 858                      (opcode != OP(ATOMIC_ACKNOWLEDGE) ||
 859                       ipath_cmp24(wqe->psn, psn) != 0))) {
 860                         /*
 861                          * The last valid PSN seen is the previous
 862                          * request's.
 863                          */
 864                         update_last_psn(qp, wqe->psn - 1);
 865                         /* Retry this request. */
 866                         ipath_restart_rc(qp, wqe->psn, &wc);
 867                         /*
 868                          * No need to process the ACK/NAK since we are
 869                          * restarting an earlier request.
 870                          */
 871                         goto bail;
 872                 }
 873                 if (qp->s_num_rd_atomic &&
 874                     (wqe->wr.opcode == IB_WR_RDMA_READ ||
 875                      wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
 876                      wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)) {
 877                         qp->s_num_rd_atomic--;
 878                         /* Restart sending task if fence is complete */
 879                         if ((qp->s_flags & IPATH_S_FENCE_PENDING) &&
 880                             !qp->s_num_rd_atomic) {
 881                                 qp->s_flags &= ~IPATH_S_FENCE_PENDING;
 882                                 tasklet_hi_schedule(&qp->s_task);
 883                         } else if (qp->s_flags & IPATH_S_RDMAR_PENDING) {
 884                                 qp->s_flags &= ~IPATH_S_RDMAR_PENDING;
 885                                 tasklet_hi_schedule(&qp->s_task);
 886                         }
 887                 }
 888                 /* Post a send completion queue entry if requested. */
 889                 if (!(qp->s_flags & IPATH_S_SIGNAL_REQ_WR) ||
 890                     (wqe->wr.send_flags & IB_SEND_SIGNALED)) {
 891                         wc.wr_id = wqe->wr.wr_id;
 892                         wc.status = IB_WC_SUCCESS;
 893                         wc.opcode = ib_ipath_wc_opcode[wqe->wr.opcode];
 894                         wc.vendor_err = 0;
 895                         wc.byte_len = wqe->length;
 896                         wc.imm_data = 0;
 897                         wc.qp = &qp->ibqp;
 898                         wc.src_qp = qp->remote_qpn;
 899                         wc.wc_flags = 0;
 900                         wc.pkey_index = 0;
 901                         wc.slid = qp->remote_ah_attr.dlid;
 902                         wc.sl = qp->remote_ah_attr.sl;
 903                         wc.dlid_path_bits = 0;
 904                         wc.port_num = 0;
 905                         ipath_cq_enter(to_icq(qp->ibqp.send_cq), &wc, 0);
 906                 }
 907                 qp->s_retry = qp->s_retry_cnt;
 908                 /*
 909                  * If we are completing a request which is in the process of
 910                  * being resent, we can stop resending it since we know the
 911                  * responder has already seen it.
 912                  */
 913                 if (qp->s_last == qp->s_cur) {
 914                         if (++qp->s_cur >= qp->s_size)
 915                                 qp->s_cur = 0;
 916                         qp->s_last = qp->s_cur;
 917                         if (qp->s_last == qp->s_tail)
 918                                 break;
 919                         wqe = get_swqe_ptr(qp, qp->s_cur);
 920                         qp->s_state = OP(SEND_LAST);
 921                         qp->s_psn = wqe->psn;
 922                 } else {
 923                         if (++qp->s_last >= qp->s_size)
 924                                 qp->s_last = 0;
 925                         if (qp->s_last == qp->s_tail)
 926                                 break;
 927                         wqe = get_swqe_ptr(qp, qp->s_last);
 928                 }
 929         }
 930
 931         switch (aeth >> 29) {
 932         case 0:         /* ACK */
 933                 dev->n_rc_acks++;
 934                 /* If this is a partial ACK, reset the retransmit timer. */
 935                 if (qp->s_last != qp->s_tail) {
 936                         spin_lock(&dev->pending_lock);
 937                         list_add_tail(&qp->timerwait,
 938                                       &dev->pending[dev->pending_index]);
 939                         spin_unlock(&dev->pending_lock);
 940                         /*
 941                          * If we get a partial ACK for a resent operation,
 942                          * we can stop resending the earlier packets and
 943                          * continue with the next packet the receiver wants.
 944                          */
 945                         if (ipath_cmp24(qp->s_psn, psn) <= 0) {
 946                                 reset_psn(qp, psn + 1);
 947                                 tasklet_hi_schedule(&qp->s_task);
 948                         }
 949                 } else if (ipath_cmp24(qp->s_psn, psn) <= 0) {
 950                         qp->s_state = OP(SEND_LAST);
 951                         qp->s_psn = psn + 1;
 952                 }
 953                 ipath_get_credit(qp, aeth);
 954                 qp->s_rnr_retry = qp->s_rnr_retry_cnt;
 955                 qp->s_retry = qp->s_retry_cnt;
 956                 update_last_psn(qp, psn);
 957                 ret = 1;
 958                 goto bail;
 959
 960         case 1:         /* RNR NAK */
 961                 dev->n_rnr_naks++;
 962                 if (qp->s_last == qp->s_tail)
 963                         goto bail;
 964                 if (qp->s_rnr_retry == 0) {
 965                         wc.status = IB_WC_RNR_RETRY_EXC_ERR;
 966                         goto class_b;
 967                 }
 968                 if (qp->s_rnr_retry_cnt < 7)
 969                         qp->s_rnr_retry--;
 970
 971                 /* The last valid PSN is the previous PSN. */
 972                 update_last_psn(qp, psn - 1);
 973
 974                 if (wqe->wr.opcode == IB_WR_RDMA_READ)
 975                         dev->n_rc_resends++;
 976                 else
 977                         dev->n_rc_resends +=
 978                                 (qp->s_psn - psn) & IPATH_PSN_MASK;
 979
 980                 reset_psn(qp, psn);
 981
 982                 qp->s_rnr_timeout =
 983                         ib_ipath_rnr_table[(aeth >> IPATH_AETH_CREDIT_SHIFT) &
 984                                            IPATH_AETH_CREDIT_MASK];
 985                 ipath_insert_rnr_queue(qp);
 986                 goto bail;
 987
 988         case 3:         /* NAK */
 989                 if (qp->s_last == qp->s_tail)
 990                         goto bail;
 991                 /* The last valid PSN is the previous PSN. */
 992                 update_last_psn(qp, psn - 1);
 993                 switch ((aeth >> IPATH_AETH_CREDIT_SHIFT) &
 994                         IPATH_AETH_CREDIT_MASK) {
 995                 case 0: /* PSN sequence error */
 996                         dev->n_seq_naks++;
 997                         /*
 998                          * Back up to the responder's expected PSN.
 999                          * Note that we might get a NAK in the middle of an
1000                          * RDMA READ response which terminates the RDMA
1001                          * READ.
1002                          */
1003                         ipath_restart_rc(qp, psn, &wc);
1004                         break;
1005
1006                 case 1: /* Invalid Request */
1007                         wc.status = IB_WC_REM_INV_REQ_ERR;
1008                         dev->n_other_naks++;
1009                         goto class_b;
1010
1011                 case 2: /* Remote Access Error */
1012                         wc.status = IB_WC_REM_ACCESS_ERR;
1013                         dev->n_other_naks++;
1014                         goto class_b;
1015
1016                 case 3: /* Remote Operation Error */
1017                         wc.status = IB_WC_REM_OP_ERR;
1018                         dev->n_other_naks++;
1019                 class_b:
1020                         wc.wr_id = wqe->wr.wr_id;
1021                         wc.opcode = ib_ipath_wc_opcode[wqe->wr.opcode];
1022                         wc.vendor_err = 0;
1023                         wc.byte_len = 0;
1024                         wc.qp = &qp->ibqp;
1025                         wc.src_qp = qp->remote_qpn;
1026                         wc.pkey_index = 0;
1027                         wc.slid = qp->remote_ah_attr.dlid;
1028                         wc.sl = qp->remote_ah_attr.sl;
1029                         wc.dlid_path_bits = 0;
1030                         wc.port_num = 0;
1031                         ipath_sqerror_qp(qp, &wc);
1032                         break;
1033
1034                 default:
1035                         /* Ignore other reserved NAK error codes */
1036                         goto reserved;
1037                 }
1038                 qp->s_rnr_retry = qp->s_rnr_retry_cnt;
1039                 goto bail;
1040
1041         default:                /* 2: reserved */
1042         reserved:
1043                 /* Ignore reserved NAK codes. */
1044                 goto bail;
1045         }
1046
1047 bail:
1048         return ret;
1049 }
1050
1051 /**
1052  * ipath_rc_rcv_resp - process an incoming RC response packet
1053  * @dev: the device this packet came in on
1054  * @ohdr: the other headers for this packet
1055  * @data: the packet data
1056  * @tlen: the packet length
1057  * @qp: the QP for this packet
1058  * @opcode: the opcode for this packet
1059  * @psn: the packet sequence number for this packet
1060  * @hdrsize: the header length
1061  * @pmtu: the path MTU
1062  * @header_in_data: true if part of the header data is in the data buffer
1063  *
1064  * This is called from ipath_rc_rcv() to process an incoming RC response
1065  * packet for the given QP.
1066  * Called at interrupt level.
1067  */
1068 static inline void ipath_rc_rcv_resp(struct ipath_ibdev *dev,
1069                                      struct ipath_other_headers *ohdr,
1070                                      void *data, u32 tlen,
1071                                      struct ipath_qp *qp,
1072                                      u32 opcode,
1073                                      u32 psn, u32 hdrsize, u32 pmtu,
1074                                      int header_in_data)
1075 {
1076         struct ipath_swqe *wqe;
1077         unsigned long flags;
1078         struct ib_wc wc;
1079         int diff;
1080         u32 pad;
1081         u32 aeth;
1082
1083         spin_lock_irqsave(&qp->s_lock, flags);
1084
1085         /* Ignore invalid responses. */
1086         if (ipath_cmp24(psn, qp->s_next_psn) >= 0)
1087                 goto ack_done;
1088
1089         /* Ignore duplicate responses. */
1090         diff = ipath_cmp24(psn, qp->s_last_psn);
1091         if (unlikely(diff <= 0)) {
1092                 /* Update credits for "ghost" ACKs */
1093                 if (diff == 0 && opcode == OP(ACKNOWLEDGE)) {
1094                         if (!header_in_data)
1095                                 aeth = be32_to_cpu(ohdr->u.aeth);
1096                         else {
1097                                 aeth = be32_to_cpu(((__be32 *) data)[0]);
1098                                 data += sizeof(__be32);
1099                         }
1100                         if ((aeth >> 29) == 0)
1101                                 ipath_get_credit(qp, aeth);
1102                 }
1103                 goto ack_done;
1104         }
1105
1106         if (unlikely(qp->s_last == qp->s_tail))
1107                 goto ack_done;
1108         wqe = get_swqe_ptr(qp, qp->s_last);
1109
1110         switch (opcode) {
1111         case OP(ACKNOWLEDGE):
1112         case OP(ATOMIC_ACKNOWLEDGE):
1113         case OP(RDMA_READ_RESPONSE_FIRST):
1114                 if (!header_in_data)
1115                         aeth = be32_to_cpu(ohdr->u.aeth);
1116                 else {
1117                         aeth = be32_to_cpu(((__be32 *) data)[0]);
1118                         data += sizeof(__be32);
1119                 }
1120                 if (opcode == OP(ATOMIC_ACKNOWLEDGE)) {
1121                         u64 val;
1122
1123                         if (!header_in_data) {
1124                                 __be32 *p = ohdr->u.at.atomic_ack_eth;
1125
1126                                 val = ((u64) be32_to_cpu(p[0]) << 32) |
1127                                         be32_to_cpu(p[1]);
1128                         } else
1129                                 val = be64_to_cpu(((__be64 *) data)[0]);
1130                         *(u64 *) wqe->sg_list[0].vaddr = val;
1131                 }
1132                 if (!do_rc_ack(qp, aeth, psn, opcode) ||
1133                     opcode != OP(RDMA_READ_RESPONSE_FIRST))
1134                         goto ack_done;
1135                 hdrsize += 4;
1136                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1137                         goto ack_op_err;
1138                 /*
1139                  * If this is a response to a resent RDMA read, we
1140                  * have to be careful to copy the data to the right
1141                  * location.
1142                  */
1143                 qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
1144                                                   wqe, psn, pmtu);
1145                 goto read_middle;
1146
1147         case OP(RDMA_READ_RESPONSE_MIDDLE):
1148                 /* no AETH, no ACK */
1149                 if (unlikely(ipath_cmp24(psn, qp->s_last_psn + 1))) {
1150                         dev->n_rdma_seq++;
1151                         ipath_restart_rc(qp, qp->s_last_psn + 1, &wc);
1152                         goto ack_done;
1153                 }
1154                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1155                         goto ack_op_err;
1156         read_middle:
1157                 if (unlikely(tlen != (hdrsize + pmtu + 4)))
1158                         goto ack_len_err;
1159                 if (unlikely(pmtu >= qp->s_rdma_read_len))
1160                         goto ack_len_err;
1161
1162                 /* We got a response so update the timeout. */
1163                 spin_lock(&dev->pending_lock);
1164                 if (qp->s_rnr_timeout == 0 && !list_empty(&qp->timerwait))
1165                         list_move_tail(&qp->timerwait,
1166                                        &dev->pending[dev->pending_index]);
1167                 spin_unlock(&dev->pending_lock);
1168                 /*
1169                  * Update the RDMA receive state but do the copy w/o
1170                  * holding the locks and blocking interrupts.
1171                  */
1172                 qp->s_rdma_read_len -= pmtu;
1173                 update_last_psn(qp, psn);
1174                 spin_unlock_irqrestore(&qp->s_lock, flags);
1175                 ipath_copy_sge(&qp->s_rdma_read_sge, data, pmtu);
1176                 goto bail;
1177
1178         case OP(RDMA_READ_RESPONSE_ONLY):
1179                 if (unlikely(ipath_cmp24(psn, qp->s_last_psn + 1))) {
1180                         dev->n_rdma_seq++;
1181                         ipath_restart_rc(qp, qp->s_last_psn + 1, &wc);
1182                         goto ack_done;
1183                 }
1184                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1185                         goto ack_op_err;
1186                 /* Get the number of bytes the message was padded by. */
1187                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1188                 /*
1189                  * Check that the data size is >= 0 && <= pmtu.
1190                  * Remember to account for the AETH header (4) and
1191                  * ICRC (4).
1192                  */
1193                 if (unlikely(tlen < (hdrsize + pad + 8)))
1194                         goto ack_len_err;
1195                 /*
1196                  * If this is a response to a resent RDMA read, we
1197                  * have to be careful to copy the data to the right
1198                  * location.
1199                  */
1200                 qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
1201                                                   wqe, psn, pmtu);
1202                 goto read_last;
1203
1204         case OP(RDMA_READ_RESPONSE_LAST):
1205                 /* ACKs READ req. */
1206                 if (unlikely(ipath_cmp24(psn, qp->s_last_psn + 1))) {
1207                         dev->n_rdma_seq++;
1208                         ipath_restart_rc(qp, qp->s_last_psn + 1, &wc);
1209                         goto ack_done;
1210                 }
1211                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1212                         goto ack_op_err;
1213                 /* Get the number of bytes the message was padded by. */
1214                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1215                 /*
1216                  * Check that the data size is >= 1 && <= pmtu.
1217                  * Remember to account for the AETH header (4) and
1218                  * ICRC (4).
1219                  */
1220                 if (unlikely(tlen <= (hdrsize + pad + 8)))
1221                         goto ack_len_err;
1222         read_last:
1223                 tlen -= hdrsize + pad + 8;
1224                 if (unlikely(tlen != qp->s_rdma_read_len))
1225                         goto ack_len_err;
1226                 if (!header_in_data)
1227                         aeth = be32_to_cpu(ohdr->u.aeth);
1228                 else {
1229                         aeth = be32_to_cpu(((__be32 *) data)[0]);
1230                         data += sizeof(__be32);
1231                 }
1232                 ipath_copy_sge(&qp->s_rdma_read_sge, data, tlen);
1233                 (void) do_rc_ack(qp, aeth, psn, OP(RDMA_READ_RESPONSE_LAST));
1234                 goto ack_done;
1235         }
1236
1237 ack_done:
1238         spin_unlock_irqrestore(&qp->s_lock, flags);
1239         goto bail;
1240
1241 ack_op_err:
1242         wc.status = IB_WC_LOC_QP_OP_ERR;
1243         goto ack_err;
1244
1245 ack_len_err:
1246         wc.status = IB_WC_LOC_LEN_ERR;
1247 ack_err:
1248         wc.wr_id = wqe->wr.wr_id;
1249         wc.opcode = ib_ipath_wc_opcode[wqe->wr.opcode];
1250         wc.vendor_err = 0;
1251         wc.byte_len = 0;
1252         wc.imm_data = 0;
1253         wc.qp = &qp->ibqp;
1254         wc.src_qp = qp->remote_qpn;
1255         wc.wc_flags = 0;
1256         wc.pkey_index = 0;
1257         wc.slid = qp->remote_ah_attr.dlid;
1258         wc.sl = qp->remote_ah_attr.sl;
1259         wc.dlid_path_bits = 0;
1260         wc.port_num = 0;
1261         ipath_sqerror_qp(qp, &wc);
1262         spin_unlock_irqrestore(&qp->s_lock, flags);
1263 bail:
1264         return;
1265 }
1266
1267 /**
1268  * ipath_rc_rcv_error - process an incoming duplicate or error RC packet
1269  * @dev: the device this packet came in on
1270  * @ohdr: the other headers for this packet
1271  * @data: the packet data
1272  * @qp: the QP for this packet
1273  * @opcode: the opcode for this packet
1274  * @psn: the packet sequence number for this packet
1275  * @diff: the difference between the PSN and the expected PSN
1276  * @header_in_data: true if part of the header data is in the data buffer
1277  *
1278  * This is called from ipath_rc_rcv() to process an unexpected
1279  * incoming RC packet for the given QP.
1280  * Called at interrupt level.
1281  * Return 1 if no more processing is needed; otherwise return 0 to
1282  * schedule a response to be sent.
1283  */
1284 static inline int ipath_rc_rcv_error(struct ipath_ibdev *dev,
1285                                      struct ipath_other_headers *ohdr,
1286                                      void *data,
1287                                      struct ipath_qp *qp,
1288                                      u32 opcode,
1289                                      u32 psn,
1290                                      int diff,
1291                                      int header_in_data)
1292 {
1293         struct ipath_ack_entry *e;
1294         u8 i, prev;
1295         int old_req;
1296         unsigned long flags;
1297
1298         if (diff > 0) {
1299                 /*
1300                  * Packet sequence error.
1301                  * A NAK will ACK earlier sends and RDMA writes.
1302                  * Don't queue the NAK if we already sent one.
1303                  */
1304                 if (!qp->r_nak_state) {
1305                         qp->r_nak_state = IB_NAK_PSN_ERROR;
1306                         /* Use the expected PSN. */
1307                         qp->r_ack_psn = qp->r_psn;
1308                         goto send_ack;
1309                 }
1310                 goto done;
1311         }
1312
1313         /*
1314          * Handle a duplicate request.  Don't re-execute SEND, RDMA
1315          * write or atomic op.  Don't NAK errors, just silently drop
1316          * the duplicate request.  Note that r_sge, r_len, and
1317          * r_rcv_len may be in use so don't modify them.
1318          *
1319          * We are supposed to ACK the earliest duplicate PSN but we
1320          * can coalesce an outstanding duplicate ACK.  We have to
1321          * send the earliest so that RDMA reads can be restarted at
1322          * the requester's expected PSN.
1323          *
1324          * First, find where this duplicate PSN falls within the
1325          * ACKs previously sent.
1326          */
1327         psn &= IPATH_PSN_MASK;
1328         e = NULL;
1329         old_req = 1;
1330         spin_lock_irqsave(&qp->s_lock, flags);
1331         for (i = qp->r_head_ack_queue; ; i = prev) {
1332                 if (i == qp->s_tail_ack_queue)
1333                         old_req = 0;
1334                 if (i)
1335                         prev = i - 1;
1336                 else
1337                         prev = IPATH_MAX_RDMA_ATOMIC;
1338                 if (prev == qp->r_head_ack_queue) {
1339                         e = NULL;
1340                         break;
1341                 }
1342                 e = &qp->s_ack_queue[prev];
1343                 if (!e->opcode) {
1344                         e = NULL;
1345                         break;
1346                 }
1347                 if (ipath_cmp24(psn, e->psn) >= 0)
1348                         break;
1349         }
1350         switch (opcode) {
1351         case OP(RDMA_READ_REQUEST): {
1352                 struct ib_reth *reth;
1353                 u32 offset;
1354                 u32 len;
1355
1356                 /*
1357                  * If we didn't find the RDMA read request in the ack queue,
1358                  * or the send tasklet is already backed up to send an
1359                  * earlier entry, we can ignore this request.
1360                  */
1361                 if (!e || e->opcode != OP(RDMA_READ_REQUEST) || old_req)
1362                         goto unlock_done;
1363                 /* RETH comes after BTH */
1364                 if (!header_in_data)
1365                         reth = &ohdr->u.rc.reth;
1366                 else {
1367                         reth = (struct ib_reth *)data;
1368                         data += sizeof(*reth);
1369                 }
1370                 /*
1371                  * Address range must be a subset of the original
1372                  * request and start on pmtu boundaries.
1373                  * We reuse the old ack_queue slot since the requester
1374                  * should not back up and request an earlier PSN for the
1375                  * same request.
1376                  */
1377                 offset = ((psn - e->psn) & IPATH_PSN_MASK) *
1378                         ib_mtu_enum_to_int(qp->path_mtu);
1379                 len = be32_to_cpu(reth->length);
1380                 if (unlikely(offset + len > e->rdma_sge.sge.sge_length))
1381                         goto unlock_done;
1382                 if (len != 0) {
1383                         u32 rkey = be32_to_cpu(reth->rkey);
1384                         u64 vaddr = be64_to_cpu(reth->vaddr);
1385                         int ok;
1386
1387                         ok = ipath_rkey_ok(qp, &e->rdma_sge,
1388                                            len, vaddr, rkey,
1389                                            IB_ACCESS_REMOTE_READ);
1390                         if (unlikely(!ok))
1391                                 goto unlock_done;
1392                 } else {
1393                         e->rdma_sge.sg_list = NULL;
1394                         e->rdma_sge.num_sge = 0;
1395                         e->rdma_sge.sge.mr = NULL;
1396                         e->rdma_sge.sge.vaddr = NULL;
1397                         e->rdma_sge.sge.length = 0;
1398                         e->rdma_sge.sge.sge_length = 0;
1399                 }
1400                 e->psn = psn;
1401                 qp->s_ack_state = OP(ACKNOWLEDGE);
1402                 qp->s_tail_ack_queue = prev;
1403                 break;
1404         }
1405
1406         case OP(COMPARE_SWAP):
1407         case OP(FETCH_ADD): {
1408                 /*
1409                  * If we didn't find the atomic request in the ack queue
1410                  * or the send tasklet is already backed up to send an
1411                  * earlier entry, we can ignore this request.
1412                  */
1413                 if (!e || e->opcode != (u8) opcode || old_req)
1414                         goto unlock_done;
1415                 qp->s_ack_state = OP(ACKNOWLEDGE);
1416                 qp->s_tail_ack_queue = prev;
1417                 break;
1418         }
1419
1420         default:
1421                 if (old_req)
1422                         goto unlock_done;
1423                 /*
1424                  * Resend the most recent ACK if this request is
1425                  * after all the previous RDMA reads and atomics.
1426                  */
1427                 if (i == qp->r_head_ack_queue) {
1428                         spin_unlock_irqrestore(&qp->s_lock, flags);
1429                         qp->r_nak_state = 0;
1430                         qp->r_ack_psn = qp->r_psn - 1;
1431                         goto send_ack;
1432                 }
1433                 /*
1434                  * Resend the RDMA read or atomic op which
1435                  * ACKs this duplicate request.
1436                  */
1437                 qp->s_ack_state = OP(ACKNOWLEDGE);
1438                 qp->s_tail_ack_queue = i;
1439                 break;
1440         }
1441         qp->r_nak_state = 0;
1442         tasklet_hi_schedule(&qp->s_task);
1443
1444 unlock_done:
1445         spin_unlock_irqrestore(&qp->s_lock, flags);
1446 done:
1447         return 1;
1448
1449 send_ack:
1450         return 0;
1451 }
1452
1453 static void ipath_rc_error(struct ipath_qp *qp, enum ib_wc_status err)
1454 {
1455         unsigned long flags;
1456
1457         spin_lock_irqsave(&qp->s_lock, flags);
1458         qp->state = IB_QPS_ERR;
1459         ipath_error_qp(qp, err);
1460         spin_unlock_irqrestore(&qp->s_lock, flags);
1461 }
1462
1463 /**
1464  * ipath_rc_rcv - process an incoming RC packet
1465  * @dev: the device this packet came in on
1466  * @hdr: the header of this packet
1467  * @has_grh: true if the header has a GRH
1468  * @data: the packet data
1469  * @tlen: the packet length
1470  * @qp: the QP for this packet
1471  *
1472  * This is called from ipath_qp_rcv() to process an incoming RC packet
1473  * for the given QP.
1474  * Called at interrupt level.
1475  */
1476 void ipath_rc_rcv(struct ipath_ibdev *dev, struct ipath_ib_header *hdr,
1477                   int has_grh, void *data, u32 tlen, struct ipath_qp *qp)
1478 {
1479         struct ipath_other_headers *ohdr;
1480         u32 opcode;
1481         u32 hdrsize;
1482         u32 psn;
1483         u32 pad;
1484         struct ib_wc wc;
1485         u32 pmtu = ib_mtu_enum_to_int(qp->path_mtu);
1486         int diff;
1487         struct ib_reth *reth;
1488         int header_in_data;
1489
1490         /* Validate the SLID. See Ch. 9.6.1.5 */
1491         if (unlikely(be16_to_cpu(hdr->lrh[3]) != qp->remote_ah_attr.dlid))
1492                 goto done;
1493
1494         /* Check for GRH */
1495         if (!has_grh) {
1496                 ohdr = &hdr->u.oth;
1497                 hdrsize = 8 + 12;       /* LRH + BTH */
1498                 psn = be32_to_cpu(ohdr->bth[2]);
1499                 header_in_data = 0;
1500         } else {
1501                 ohdr = &hdr->u.l.oth;
1502                 hdrsize = 8 + 40 + 12;  /* LRH + GRH + BTH */
1503                 /*
1504                  * The header with GRH is 60 bytes and the core driver sets
1505                  * the eager header buffer size to 56 bytes so the last 4
1506                  * bytes of the BTH header (PSN) is in the data buffer.
1507                  */
1508                 header_in_data = dev->dd->ipath_rcvhdrentsize == 16;
1509                 if (header_in_data) {
1510                         psn = be32_to_cpu(((__be32 *) data)[0]);
1511                         data += sizeof(__be32);
1512                 } else
1513                         psn = be32_to_cpu(ohdr->bth[2]);
1514         }
1515
1516         /*
1517          * Process responses (ACKs) before anything else.  Note that the
1518          * packet sequence number will be for something in the send work
1519          * queue rather than the expected receive packet sequence number.
1520          * In other words, this QP is the requester.
1521          */
1522         opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
1523         if (opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
1524             opcode <= OP(ATOMIC_ACKNOWLEDGE)) {
1525                 ipath_rc_rcv_resp(dev, ohdr, data, tlen, qp, opcode, psn,
1526                                   hdrsize, pmtu, header_in_data);
1527                 goto done;
1528         }
1529
1530         /* Compute 24 bits worth of difference. */
1531         diff = ipath_cmp24(psn, qp->r_psn);
1532         if (unlikely(diff)) {
1533                 if (ipath_rc_rcv_error(dev, ohdr, data, qp, opcode,
1534                                        psn, diff, header_in_data))
1535                         goto done;
1536                 goto send_ack;
1537         }
1538
1539         /* Check for opcode sequence errors. */
1540         switch (qp->r_state) {
1541         case OP(SEND_FIRST):
1542         case OP(SEND_MIDDLE):
1543                 if (opcode == OP(SEND_MIDDLE) ||
1544                     opcode == OP(SEND_LAST) ||
1545                     opcode == OP(SEND_LAST_WITH_IMMEDIATE))
1546                         break;
1547         nack_inv:
1548                 ipath_rc_error(qp, IB_WC_REM_INV_REQ_ERR);
1549                 qp->r_nak_state = IB_NAK_INVALID_REQUEST;
1550                 qp->r_ack_psn = qp->r_psn;
1551                 goto send_ack;
1552
1553         case OP(RDMA_WRITE_FIRST):
1554         case OP(RDMA_WRITE_MIDDLE):
1555                 if (opcode == OP(RDMA_WRITE_MIDDLE) ||
1556                     opcode == OP(RDMA_WRITE_LAST) ||
1557                     opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
1558                         break;
1559                 goto nack_inv;
1560
1561         default:
1562                 if (opcode == OP(SEND_MIDDLE) ||
1563                     opcode == OP(SEND_LAST) ||
1564                     opcode == OP(SEND_LAST_WITH_IMMEDIATE) ||
1565                     opcode == OP(RDMA_WRITE_MIDDLE) ||
1566                     opcode == OP(RDMA_WRITE_LAST) ||
1567                     opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
1568                         goto nack_inv;
1569                 /*
1570                  * Note that it is up to the requester to not send a new
1571                  * RDMA read or atomic operation before receiving an ACK
1572                  * for the previous operation.
1573                  */
1574                 break;
1575         }
1576
1577         wc.imm_data = 0;
1578         wc.wc_flags = 0;
1579
1580         /* OK, process the packet. */
1581         switch (opcode) {
1582         case OP(SEND_FIRST):
1583                 if (!ipath_get_rwqe(qp, 0)) {
1584                 rnr_nak:
1585                         /*
1586                          * A RNR NAK will ACK earlier sends and RDMA writes.
1587                          * Don't queue the NAK if a RDMA read or atomic
1588                          * is pending though.
1589                          */
1590                         if (qp->r_nak_state)
1591                                 goto done;
1592                         qp->r_nak_state = IB_RNR_NAK | qp->r_min_rnr_timer;
1593                         qp->r_ack_psn = qp->r_psn;
1594                         goto send_ack;
1595                 }
1596                 qp->r_rcv_len = 0;
1597                 /* FALLTHROUGH */
1598         case OP(SEND_MIDDLE):
1599         case OP(RDMA_WRITE_MIDDLE):
1600         send_middle:
1601                 /* Check for invalid length PMTU or posted rwqe len. */
1602                 if (unlikely(tlen != (hdrsize + pmtu + 4)))
1603                         goto nack_inv;
1604                 qp->r_rcv_len += pmtu;
1605                 if (unlikely(qp->r_rcv_len > qp->r_len))
1606                         goto nack_inv;
1607                 ipath_copy_sge(&qp->r_sge, data, pmtu);
1608                 break;
1609
1610         case OP(RDMA_WRITE_LAST_WITH_IMMEDIATE):
1611                 /* consume RWQE */
1612                 if (!ipath_get_rwqe(qp, 1))
1613                         goto rnr_nak;
1614                 goto send_last_imm;
1615
1616         case OP(SEND_ONLY):
1617         case OP(SEND_ONLY_WITH_IMMEDIATE):
1618                 if (!ipath_get_rwqe(qp, 0))
1619                         goto rnr_nak;
1620                 qp->r_rcv_len = 0;
1621                 if (opcode == OP(SEND_ONLY))
1622                         goto send_last;
1623                 /* FALLTHROUGH */
1624         case OP(SEND_LAST_WITH_IMMEDIATE):
1625         send_last_imm:
1626                 if (header_in_data) {
1627                         wc.imm_data = *(__be32 *) data;
1628                         data += sizeof(__be32);
1629                 } else {
1630                         /* Immediate data comes after BTH */
1631                         wc.imm_data = ohdr->u.imm_data;
1632                 }
1633                 hdrsize += 4;
1634                 wc.wc_flags = IB_WC_WITH_IMM;
1635                 /* FALLTHROUGH */
1636         case OP(SEND_LAST):
1637         case OP(RDMA_WRITE_LAST):
1638         send_last:
1639                 /* Get the number of bytes the message was padded by. */
1640                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1641                 /* Check for invalid length. */
1642                 /* XXX LAST len should be >= 1 */
1643                 if (unlikely(tlen < (hdrsize + pad + 4)))
1644                         goto nack_inv;
1645                 /* Don't count the CRC. */
1646                 tlen -= (hdrsize + pad + 4);
1647                 wc.byte_len = tlen + qp->r_rcv_len;
1648                 if (unlikely(wc.byte_len > qp->r_len))
1649                         goto nack_inv;
1650                 ipath_copy_sge(&qp->r_sge, data, tlen);
1651                 qp->r_msn++;
1652                 if (!qp->r_wrid_valid)
1653                         break;
1654                 qp->r_wrid_valid = 0;
1655                 wc.wr_id = qp->r_wr_id;
1656                 wc.status = IB_WC_SUCCESS;
1657                 wc.opcode = IB_WC_RECV;
1658                 wc.vendor_err = 0;
1659                 wc.qp = &qp->ibqp;
1660                 wc.src_qp = qp->remote_qpn;
1661                 wc.pkey_index = 0;
1662                 wc.slid = qp->remote_ah_attr.dlid;
1663                 wc.sl = qp->remote_ah_attr.sl;
1664                 wc.dlid_path_bits = 0;
1665                 wc.port_num = 0;
1666                 /* Signal completion event if the solicited bit is set. */
1667                 ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
1668                                (ohdr->bth[0] &
1669                                 __constant_cpu_to_be32(1 << 23)) != 0);
1670                 break;
1671
1672         case OP(RDMA_WRITE_FIRST):
1673         case OP(RDMA_WRITE_ONLY):
1674         case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE):
1675                 /* consume RWQE */
1676                 /* RETH comes after BTH */
1677                 if (!header_in_data)
1678                         reth = &ohdr->u.rc.reth;
1679                 else {
1680                         reth = (struct ib_reth *)data;
1681                         data += sizeof(*reth);
1682                 }
1683                 hdrsize += sizeof(*reth);
1684                 qp->r_len = be32_to_cpu(reth->length);
1685                 qp->r_rcv_len = 0;
1686                 if (qp->r_len != 0) {
1687                         u32 rkey = be32_to_cpu(reth->rkey);
1688                         u64 vaddr = be64_to_cpu(reth->vaddr);
1689                         int ok;
1690
1691                         /* Check rkey & NAK */
1692                         ok = ipath_rkey_ok(qp, &qp->r_sge,
1693                                            qp->r_len, vaddr, rkey,
1694                                            IB_ACCESS_REMOTE_WRITE);
1695                         if (unlikely(!ok))
1696                                 goto nack_acc;
1697                 } else {
1698                         qp->r_sge.sg_list = NULL;
1699                         qp->r_sge.sge.mr = NULL;
1700                         qp->r_sge.sge.vaddr = NULL;
1701                         qp->r_sge.sge.length = 0;
1702                         qp->r_sge.sge.sge_length = 0;
1703                 }
1704                 if (unlikely(!(qp->qp_access_flags &
1705                                IB_ACCESS_REMOTE_WRITE)))
1706                         goto nack_acc;
1707                 if (opcode == OP(RDMA_WRITE_FIRST))
1708                         goto send_middle;
1709                 else if (opcode == OP(RDMA_WRITE_ONLY))
1710                         goto send_last;
1711                 if (!ipath_get_rwqe(qp, 1))
1712                         goto rnr_nak;
1713                 goto send_last_imm;
1714
1715         case OP(RDMA_READ_REQUEST): {
1716                 struct ipath_ack_entry *e;
1717                 u32 len;
1718                 u8 next;
1719
1720                 if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_READ)))
1721                         goto nack_acc;
1722                 next = qp->r_head_ack_queue + 1;
1723                 if (next > IPATH_MAX_RDMA_ATOMIC)
1724                         next = 0;
1725                 if (unlikely(next == qp->s_tail_ack_queue))
1726                         goto nack_inv;
1727                 e = &qp->s_ack_queue[qp->r_head_ack_queue];
1728                 /* RETH comes after BTH */
1729                 if (!header_in_data)
1730                         reth = &ohdr->u.rc.reth;
1731                 else {
1732                         reth = (struct ib_reth *)data;
1733                         data += sizeof(*reth);
1734                 }
1735                 len = be32_to_cpu(reth->length);
1736                 if (len) {
1737                         u32 rkey = be32_to_cpu(reth->rkey);
1738                         u64 vaddr = be64_to_cpu(reth->vaddr);
1739                         int ok;
1740
1741                         /* Check rkey & NAK */
1742                         ok = ipath_rkey_ok(qp, &e->rdma_sge, len, vaddr,
1743                                            rkey, IB_ACCESS_REMOTE_READ);
1744                         if (unlikely(!ok))
1745                                 goto nack_acc;
1746                         /*
1747                          * Update the next expected PSN.  We add 1 later
1748                          * below, so only add the remainder here.
1749                          */
1750                         if (len > pmtu)
1751                                 qp->r_psn += (len - 1) / pmtu;
1752                 } else {
1753                         e->rdma_sge.sg_list = NULL;
1754                         e->rdma_sge.num_sge = 0;
1755                         e->rdma_sge.sge.mr = NULL;
1756                         e->rdma_sge.sge.vaddr = NULL;
1757                         e->rdma_sge.sge.length = 0;
1758                         e->rdma_sge.sge.sge_length = 0;
1759                 }
1760                 e->opcode = opcode;
1761                 e->psn = psn;
1762                 /*
1763                  * We need to increment the MSN here instead of when we
1764                  * finish sending the result since a duplicate request would
1765                  * increment it more than once.
1766                  */
1767                 qp->r_msn++;
1768                 qp->r_psn++;
1769                 qp->r_state = opcode;
1770                 qp->r_nak_state = 0;
1771                 barrier();
1772                 qp->r_head_ack_queue = next;
1773
1774                 /* Call ipath_do_rc_send() in another thread. */
1775                 tasklet_hi_schedule(&qp->s_task);
1776
1777                 goto done;
1778         }
1779
1780         case OP(COMPARE_SWAP):
1781         case OP(FETCH_ADD): {
1782                 struct ib_atomic_eth *ateth;
1783                 struct ipath_ack_entry *e;
1784                 u64 vaddr;
1785                 atomic64_t *maddr;
1786                 u64 sdata;
1787                 u32 rkey;
1788                 u8 next;
1789
1790                 if (unlikely(!(qp->qp_access_flags &
1791                                IB_ACCESS_REMOTE_ATOMIC)))
1792                         goto nack_acc;
1793                 next = qp->r_head_ack_queue + 1;
1794                 if (next > IPATH_MAX_RDMA_ATOMIC)
1795                         next = 0;
1796                 if (unlikely(next == qp->s_tail_ack_queue))
1797                         goto nack_inv;
1798                 if (!header_in_data)
1799                         ateth = &ohdr->u.atomic_eth;
1800                 else
1801                         ateth = (struct ib_atomic_eth *)data;
1802                 vaddr = ((u64) be32_to_cpu(ateth->vaddr[0]) << 32) |
1803                         be32_to_cpu(ateth->vaddr[1]);
1804                 if (unlikely(vaddr & (sizeof(u64) - 1)))
1805                         goto nack_inv;
1806                 rkey = be32_to_cpu(ateth->rkey);
1807                 /* Check rkey & NAK */
1808                 if (unlikely(!ipath_rkey_ok(qp, &qp->r_sge,
1809                                             sizeof(u64), vaddr, rkey,
1810                                             IB_ACCESS_REMOTE_ATOMIC)))
1811                         goto nack_acc;
1812                 /* Perform atomic OP and save result. */
1813                 maddr = (atomic64_t *) qp->r_sge.sge.vaddr;
1814                 sdata = be64_to_cpu(ateth->swap_data);
1815                 e = &qp->s_ack_queue[qp->r_head_ack_queue];
1816                 e->atomic_data = (opcode == OP(FETCH_ADD)) ?
1817                         (u64) atomic64_add_return(sdata, maddr) - sdata :
1818                         (u64) cmpxchg((u64 *) qp->r_sge.sge.vaddr,
1819                                       be64_to_cpu(ateth->compare_data),
1820                                       sdata);
1821                 e->opcode = opcode;
1822                 e->psn = psn & IPATH_PSN_MASK;
1823                 qp->r_msn++;
1824                 qp->r_psn++;
1825                 qp->r_state = opcode;
1826                 qp->r_nak_state = 0;
1827                 barrier();
1828                 qp->r_head_ack_queue = next;
1829
1830                 /* Call ipath_do_rc_send() in another thread. */
1831                 tasklet_hi_schedule(&qp->s_task);
1832
1833                 goto done;
1834         }
1835
1836         default:
1837                 /* NAK unknown opcodes. */
1838                 goto nack_inv;
1839         }
1840         qp->r_psn++;
1841         qp->r_state = opcode;
1842         qp->r_ack_psn = psn;
1843         qp->r_nak_state = 0;
1844         /* Send an ACK if requested or required. */
1845         if (psn & (1 << 31))
1846                 goto send_ack;
1847         goto done;
1848
1849 nack_acc:
1850         ipath_rc_error(qp, IB_WC_REM_ACCESS_ERR);
1851         qp->r_nak_state = IB_NAK_REMOTE_ACCESS_ERROR;
1852         qp->r_ack_psn = qp->r_psn;
1853
1854 send_ack:
1855         send_rc_ack(qp);
1856
1857 done:
1858         return;
1859 }