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