drivers/infiniband/hw/ipath/ipath_rc.c

   1 /*
   2  * Copyright (c) 2005, 2006 PathScale, Inc. All rights reserved.
   3  *
   4  * This software is available to you under a choice of one of two
   5  * licenses.  You may choose to be licensed under the terms of the GNU
   6  * General Public License (GPL) Version 2, available from the file
   7  * COPYING in the main directory of this source tree, or the
   8  * OpenIB.org BSD license below:
   9  *
  10  *     Redistribution and use in source and binary forms, with or
  11  *     without modification, are permitted provided that the following
  12  *     conditions are met:
  13  *
  14  *      - Redistributions of source code must retain the above
  15  *        copyright notice, this list of conditions and the following
  16  *        disclaimer.
  17  *
  18  *      - Redistributions in binary form must reproduce the above
  19  *        copyright notice, this list of conditions and the following
  20  *        disclaimer in the documentation and/or other materials
  21  *        provided with the distribution.
  22  *
  23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  30  * SOFTWARE.
  31  */
  32
  33 #include "ipath_verbs.h"
  34 #include "ips_common.h"
  35
  36 /* cut down ridiculously long IB macro names */
  37 #define OP(x) IB_OPCODE_RC_##x
  38
  39 /**
  40  * ipath_init_restart- initialize the qp->s_sge after a restart
  41  * @qp: the QP who's SGE we're restarting
  42  * @wqe: the work queue to initialize the QP's SGE from
  43  *
  44  * The QP s_lock should be held.
  45  */
  46 static void ipath_init_restart(struct ipath_qp *qp, struct ipath_swqe *wqe)
  47 {
  48         struct ipath_ibdev *dev;
  49         u32 len;
  50
  51         len = ((qp->s_psn - wqe->psn) & IPS_PSN_MASK) *
  52                 ib_mtu_enum_to_int(qp->path_mtu);
  53         qp->s_sge.sge = wqe->sg_list[0];
  54         qp->s_sge.sg_list = wqe->sg_list + 1;
  55         qp->s_sge.num_sge = wqe->wr.num_sge;
  56         ipath_skip_sge(&qp->s_sge, len);
  57         qp->s_len = wqe->length - len;
  58         dev = to_idev(qp->ibqp.device);
  59         spin_lock(&dev->pending_lock);
  60         if (qp->timerwait.next == LIST_POISON1)
  61                 list_add_tail(&qp->timerwait,
  62                               &dev->pending[dev->pending_index]);
  63         spin_unlock(&dev->pending_lock);
  64 }
  65
  66 /**
  67  * ipath_make_rc_ack - construct a response packet (ACK, NAK, or RDMA read)
  68  * @qp: a pointer to the QP
  69  * @ohdr: a pointer to the IB header being constructed
  70  * @pmtu: the path MTU
  71  *
  72  * Return bth0 if constructed; otherwise, return 0.
  73  * Note the QP s_lock must be held.
  74  */
  75 static inline u32 ipath_make_rc_ack(struct ipath_qp *qp,
  76                                     struct ipath_other_headers *ohdr,
  77                                     u32 pmtu)
  78 {
  79         struct ipath_sge_state *ss;
  80         u32 hwords;
  81         u32 len;
  82         u32 bth0;
  83
  84         /* header size in 32-bit words LRH+BTH = (8+12)/4. */
  85         hwords = 5;
  86
  87         /*
  88          * Send a response.  Note that we are in the responder's
  89          * side of the QP context.
  90          */
  91         switch (qp->s_ack_state) {
  92         case OP(RDMA_READ_REQUEST):
  93                 ss = &qp->s_rdma_sge;
  94                 len = qp->s_rdma_len;
  95                 if (len > pmtu) {
  96                         len = pmtu;
  97                         qp->s_ack_state = OP(RDMA_READ_RESPONSE_FIRST);
  98                 }
  99                 else
 100                         qp->s_ack_state = OP(RDMA_READ_RESPONSE_ONLY);
 101                 qp->s_rdma_len -= len;
 102                 bth0 = qp->s_ack_state << 24;
 103                 ohdr->u.aeth = ipath_compute_aeth(qp);
 104                 hwords++;
 105                 break;
 106
 107         case OP(RDMA_READ_RESPONSE_FIRST):
 108                 qp->s_ack_state = OP(RDMA_READ_RESPONSE_MIDDLE);
 109                 /* FALLTHROUGH */
 110         case OP(RDMA_READ_RESPONSE_MIDDLE):
 111                 ss = &qp->s_rdma_sge;
 112                 len = qp->s_rdma_len;
 113                 if (len > pmtu)
 114                         len = pmtu;
 115                 else {
 116                         ohdr->u.aeth = ipath_compute_aeth(qp);
 117                         hwords++;
 118                         qp->s_ack_state = OP(RDMA_READ_RESPONSE_LAST);
 119                 }
 120                 qp->s_rdma_len -= len;
 121                 bth0 = qp->s_ack_state << 24;
 122                 break;
 123
 124         case OP(RDMA_READ_RESPONSE_LAST):
 125         case OP(RDMA_READ_RESPONSE_ONLY):
 126                 /*
 127                  * We have to prevent new requests from changing
 128                  * the r_sge state while a ipath_verbs_send()
 129                  * is in progress.
 130                  * Changing r_state allows the receiver
 131                  * to continue processing new packets.
 132                  * We do it here now instead of above so
 133                  * that we are sure the packet was sent before
 134                  * changing the state.
 135                  */
 136                 qp->r_state = OP(RDMA_READ_RESPONSE_LAST);
 137                 qp->s_ack_state = OP(ACKNOWLEDGE);
 138                 return 0;
 139
 140         case OP(COMPARE_SWAP):
 141         case OP(FETCH_ADD):
 142                 ss = NULL;
 143                 len = 0;
 144                 qp->r_state = OP(SEND_LAST);
 145                 qp->s_ack_state = OP(ACKNOWLEDGE);
 146                 bth0 = IB_OPCODE_ATOMIC_ACKNOWLEDGE << 24;
 147                 ohdr->u.at.aeth = ipath_compute_aeth(qp);
 148                 ohdr->u.at.atomic_ack_eth = cpu_to_be64(qp->s_ack_atomic);
 149                 hwords += sizeof(ohdr->u.at) / 4;
 150                 break;
 151
 152         default:
 153                 /* Send a regular ACK. */
 154                 ss = NULL;
 155                 len = 0;
 156                 qp->s_ack_state = OP(ACKNOWLEDGE);
 157                 bth0 = qp->s_ack_state << 24;
 158                 ohdr->u.aeth = ipath_compute_aeth(qp);
 159                 hwords++;
 160         }
 161         qp->s_hdrwords = hwords;
 162         qp->s_cur_sge = ss;
 163         qp->s_cur_size = len;
 164
 165         return bth0;
 166 }
 167
 168 /**
 169  * ipath_make_rc_req - construct a request packet (SEND, RDMA r/w, ATOMIC)
 170  * @qp: a pointer to the QP
 171  * @ohdr: a pointer to the IB header being constructed
 172  * @pmtu: the path MTU
 173  * @bth0p: pointer to the BTH opcode word
 174  * @bth2p: pointer to the BTH PSN word
 175  *
 176  * Return 1 if constructed; otherwise, return 0.
 177  * Note the QP s_lock must be held.
 178  */
 179 static inline int ipath_make_rc_req(struct ipath_qp *qp,
 180                                     struct ipath_other_headers *ohdr,
 181                                     u32 pmtu, u32 *bth0p, u32 *bth2p)
 182 {
 183         struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
 184         struct ipath_sge_state *ss;
 185         struct ipath_swqe *wqe;
 186         u32 hwords;
 187         u32 len;
 188         u32 bth0;
 189         u32 bth2;
 190         char newreq;
 191
 192         if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_SEND_OK) ||
 193             qp->s_rnr_timeout)
 194                 goto done;
 195
 196         /* header size in 32-bit words LRH+BTH = (8+12)/4. */
 197         hwords = 5;
 198         bth0 = 0;
 199
 200         /* Send a request. */
 201         wqe = get_swqe_ptr(qp, qp->s_cur);
 202         switch (qp->s_state) {
 203         default:
 204                 /*
 205                  * Resend an old request or start a new one.
 206                  *
 207                  * We keep track of the current SWQE so that
 208                  * we don't reset the "furthest progress" state
 209                  * if we need to back up.
 210                  */
 211                 newreq = 0;
 212                 if (qp->s_cur == qp->s_tail) {
 213                         /* Check if send work queue is empty. */
 214                         if (qp->s_tail == qp->s_head)
 215                                 goto done;
 216                         qp->s_psn = wqe->psn = qp->s_next_psn;
 217                         newreq = 1;
 218                 }
 219                 /*
 220                  * Note that we have to be careful not to modify the
 221                  * original work request since we may need to resend
 222                  * it.
 223                  */
 224                 qp->s_sge.sge = wqe->sg_list[0];
 225                 qp->s_sge.sg_list = wqe->sg_list + 1;
 226                 qp->s_sge.num_sge = wqe->wr.num_sge;
 227                 qp->s_len = len = wqe->length;
 228                 ss = &qp->s_sge;
 229                 bth2 = 0;
 230                 switch (wqe->wr.opcode) {
 231                 case IB_WR_SEND:
 232                 case IB_WR_SEND_WITH_IMM:
 233                         /* If no credit, return. */
 234                         if (qp->s_lsn != (u32) -1 &&
 235                             ipath_cmp24(wqe->ssn, qp->s_lsn + 1) > 0)
 236                                 goto done;
 237                         wqe->lpsn = wqe->psn;
 238                         if (len > pmtu) {
 239                                 wqe->lpsn += (len - 1) / pmtu;
 240                                 qp->s_state = OP(SEND_FIRST);
 241                                 len = pmtu;
 242                                 break;
 243                         }
 244                         if (wqe->wr.opcode == IB_WR_SEND)
 245                                 qp->s_state = OP(SEND_ONLY);
 246                         else {
 247                                 qp->s_state = OP(SEND_ONLY_WITH_IMMEDIATE);
 248                                 /* Immediate data comes after the BTH */
 249                                 ohdr->u.imm_data = wqe->wr.imm_data;
 250                                 hwords += 1;
 251                         }
 252                         if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 253                                 bth0 |= 1 << 23;
 254                         bth2 = 1 << 31; /* Request ACK. */
 255                         if (++qp->s_cur == qp->s_size)
 256                                 qp->s_cur = 0;
 257                         break;
 258
 259                 case IB_WR_RDMA_WRITE:
 260                         if (newreq)
 261                                 qp->s_lsn++;
 262                         /* FALLTHROUGH */
 263                 case IB_WR_RDMA_WRITE_WITH_IMM:
 264                         /* If no credit, return. */
 265                         if (qp->s_lsn != (u32) -1 &&
 266                             ipath_cmp24(wqe->ssn, qp->s_lsn + 1) > 0)
 267                                 goto done;
 268                         ohdr->u.rc.reth.vaddr =
 269                                 cpu_to_be64(wqe->wr.wr.rdma.remote_addr);
 270                         ohdr->u.rc.reth.rkey =
 271                                 cpu_to_be32(wqe->wr.wr.rdma.rkey);
 272                         ohdr->u.rc.reth.length = cpu_to_be32(len);
 273                         hwords += sizeof(struct ib_reth) / 4;
 274                         wqe->lpsn = wqe->psn;
 275                         if (len > pmtu) {
 276                                 wqe->lpsn += (len - 1) / pmtu;
 277                                 qp->s_state = OP(RDMA_WRITE_FIRST);
 278                                 len = pmtu;
 279                                 break;
 280                         }
 281                         if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
 282                                 qp->s_state = OP(RDMA_WRITE_ONLY);
 283                         else {
 284                                 qp->s_state =
 285                                         OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE);
 286                                 /* Immediate data comes
 287                                  * after RETH */
 288                                 ohdr->u.rc.imm_data = wqe->wr.imm_data;
 289                                 hwords += 1;
 290                                 if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 291                                         bth0 |= 1 << 23;
 292                         }
 293                         bth2 = 1 << 31; /* Request ACK. */
 294                         if (++qp->s_cur == qp->s_size)
 295                                 qp->s_cur = 0;
 296                         break;
 297
 298                 case IB_WR_RDMA_READ:
 299                         ohdr->u.rc.reth.vaddr =
 300                                 cpu_to_be64(wqe->wr.wr.rdma.remote_addr);
 301                         ohdr->u.rc.reth.rkey =
 302                                 cpu_to_be32(wqe->wr.wr.rdma.rkey);
 303                         ohdr->u.rc.reth.length = cpu_to_be32(len);
 304                         qp->s_state = OP(RDMA_READ_REQUEST);
 305                         hwords += sizeof(ohdr->u.rc.reth) / 4;
 306                         if (newreq) {
 307                                 qp->s_lsn++;
 308                                 /*
 309                                  * Adjust s_next_psn to count the
 310                                  * expected number of responses.
 311                                  */
 312                                 if (len > pmtu)
 313                                         qp->s_next_psn += (len - 1) / pmtu;
 314                                 wqe->lpsn = qp->s_next_psn++;
 315                         }
 316                         ss = NULL;
 317                         len = 0;
 318                         if (++qp->s_cur == qp->s_size)
 319                                 qp->s_cur = 0;
 320                         break;
 321
 322                 case IB_WR_ATOMIC_CMP_AND_SWP:
 323                 case IB_WR_ATOMIC_FETCH_AND_ADD:
 324                         if (wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP)
 325                                 qp->s_state = OP(COMPARE_SWAP);
 326                         else
 327                                 qp->s_state = OP(FETCH_ADD);
 328                         ohdr->u.atomic_eth.vaddr = cpu_to_be64(
 329                                 wqe->wr.wr.atomic.remote_addr);
 330                         ohdr->u.atomic_eth.rkey = cpu_to_be32(
 331                                 wqe->wr.wr.atomic.rkey);
 332                         ohdr->u.atomic_eth.swap_data = cpu_to_be64(
 333                                 wqe->wr.wr.atomic.swap);
 334                         ohdr->u.atomic_eth.compare_data = cpu_to_be64(
 335                                 wqe->wr.wr.atomic.compare_add);
 336                         hwords += sizeof(struct ib_atomic_eth) / 4;
 337                         if (newreq) {
 338                                 qp->s_lsn++;
 339                                 wqe->lpsn = wqe->psn;
 340                         }
 341                         if (++qp->s_cur == qp->s_size)
 342                                 qp->s_cur = 0;
 343                         ss = NULL;
 344                         len = 0;
 345                         break;
 346
 347                 default:
 348                         goto done;
 349                 }
 350                 if (newreq) {
 351                         qp->s_tail++;
 352                         if (qp->s_tail >= qp->s_size)
 353                                 qp->s_tail = 0;
 354                 }
 355                 bth2 |= qp->s_psn++ & IPS_PSN_MASK;
 356                 if ((int)(qp->s_psn - qp->s_next_psn) > 0)
 357                         qp->s_next_psn = qp->s_psn;
 358                 spin_lock(&dev->pending_lock);
 359                 if (qp->timerwait.next == LIST_POISON1)
 360                         list_add_tail(&qp->timerwait,
 361                                       &dev->pending[dev->pending_index]);
 362                 spin_unlock(&dev->pending_lock);
 363                 break;
 364
 365         case OP(RDMA_READ_RESPONSE_FIRST):
 366                 /*
 367                  * This case can only happen if a send is restarted.  See
 368                  * ipath_restart_rc().
 369                  */
 370                 ipath_init_restart(qp, wqe);
 371                 /* FALLTHROUGH */
 372         case OP(SEND_FIRST):
 373                 qp->s_state = OP(SEND_MIDDLE);
 374                 /* FALLTHROUGH */
 375         case OP(SEND_MIDDLE):
 376                 bth2 = qp->s_psn++ & IPS_PSN_MASK;
 377                 if ((int)(qp->s_psn - qp->s_next_psn) > 0)
 378                         qp->s_next_psn = qp->s_psn;
 379                 ss = &qp->s_sge;
 380                 len = qp->s_len;
 381                 if (len > pmtu) {
 382                         /*
 383                          * Request an ACK every 1/2 MB to avoid retransmit
 384                          * timeouts.
 385                          */
 386                         if (((wqe->length - len) % (512 * 1024)) == 0)
 387                                 bth2 |= 1 << 31;
 388                         len = pmtu;
 389                         break;
 390                 }
 391                 if (wqe->wr.opcode == IB_WR_SEND)
 392                         qp->s_state = OP(SEND_LAST);
 393                 else {
 394                         qp->s_state = OP(SEND_LAST_WITH_IMMEDIATE);
 395                         /* Immediate data comes after the BTH */
 396                         ohdr->u.imm_data = wqe->wr.imm_data;
 397                         hwords += 1;
 398                 }
 399                 if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 400                         bth0 |= 1 << 23;
 401                 bth2 |= 1 << 31;        /* Request ACK. */
 402                 qp->s_cur++;
 403                 if (qp->s_cur >= qp->s_size)
 404                         qp->s_cur = 0;
 405                 break;
 406
 407         case OP(RDMA_READ_RESPONSE_LAST):
 408                 /*
 409                  * This case can only happen if a RDMA write is restarted.
 410                  * See ipath_restart_rc().
 411                  */
 412                 ipath_init_restart(qp, wqe);
 413                 /* FALLTHROUGH */
 414         case OP(RDMA_WRITE_FIRST):
 415                 qp->s_state = OP(RDMA_WRITE_MIDDLE);
 416                 /* FALLTHROUGH */
 417         case OP(RDMA_WRITE_MIDDLE):
 418                 bth2 = qp->s_psn++ & IPS_PSN_MASK;
 419                 if ((int)(qp->s_psn - qp->s_next_psn) > 0)
 420                         qp->s_next_psn = qp->s_psn;
 421                 ss = &qp->s_sge;
 422                 len = qp->s_len;
 423                 if (len > pmtu) {
 424                         /*
 425                          * Request an ACK every 1/2 MB to avoid retransmit
 426                          * timeouts.
 427                          */
 428                         if (((wqe->length - len) % (512 * 1024)) == 0)
 429                                 bth2 |= 1 << 31;
 430                         len = pmtu;
 431                         break;
 432                 }
 433                 if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
 434                         qp->s_state = OP(RDMA_WRITE_LAST);
 435                 else {
 436                         qp->s_state = OP(RDMA_WRITE_LAST_WITH_IMMEDIATE);
 437                         /* Immediate data comes after the BTH */
 438                         ohdr->u.imm_data = wqe->wr.imm_data;
 439                         hwords += 1;
 440                         if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 441                                 bth0 |= 1 << 23;
 442                 }
 443                 bth2 |= 1 << 31;        /* Request ACK. */
 444                 qp->s_cur++;
 445                 if (qp->s_cur >= qp->s_size)
 446                         qp->s_cur = 0;
 447                 break;
 448
 449         case OP(RDMA_READ_RESPONSE_MIDDLE):
 450                 /*
 451                  * This case can only happen if a RDMA read is restarted.
 452                  * See ipath_restart_rc().
 453                  */
 454                 ipath_init_restart(qp, wqe);
 455                 len = ((qp->s_psn - wqe->psn) & IPS_PSN_MASK) * pmtu;
 456                 ohdr->u.rc.reth.vaddr =
 457                         cpu_to_be64(wqe->wr.wr.rdma.remote_addr + len);
 458                 ohdr->u.rc.reth.rkey =
 459                         cpu_to_be32(wqe->wr.wr.rdma.rkey);
 460                 ohdr->u.rc.reth.length = cpu_to_be32(qp->s_len);
 461                 qp->s_state = OP(RDMA_READ_REQUEST);
 462                 hwords += sizeof(ohdr->u.rc.reth) / 4;
 463                 bth2 = qp->s_psn++ & IPS_PSN_MASK;
 464                 if ((int)(qp->s_psn - qp->s_next_psn) > 0)
 465                         qp->s_next_psn = qp->s_psn;
 466                 ss = NULL;
 467                 len = 0;
 468                 qp->s_cur++;
 469                 if (qp->s_cur == qp->s_size)
 470                         qp->s_cur = 0;
 471                 break;
 472
 473         case OP(RDMA_READ_REQUEST):
 474         case OP(COMPARE_SWAP):
 475         case OP(FETCH_ADD):
 476                 /*
 477                  * We shouldn't start anything new until this request is
 478                  * finished.  The ACK will handle rescheduling us.  XXX The
 479                  * number of outstanding ones is negotiated at connection
 480                  * setup time (see pg. 258,289)?  XXX Also, if we support
 481                  * multiple outstanding requests, we need to check the WQE
 482                  * IB_SEND_FENCE flag and not send a new request if a RDMA
 483                  * read or atomic is pending.
 484                  */
 485                 goto done;
 486         }
 487         qp->s_len -= len;
 488         qp->s_hdrwords = hwords;
 489         qp->s_cur_sge = ss;
 490         qp->s_cur_size = len;
 491         *bth0p = bth0 | (qp->s_state << 24);
 492         *bth2p = bth2;
 493         return 1;
 494
 495 done:
 496         return 0;
 497 }
 498
 499 static inline void ipath_make_rc_grh(struct ipath_qp *qp,
 500                                      struct ib_global_route *grh,
 501                                      u32 nwords)
 502 {
 503         struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
 504
 505         /* GRH header size in 32-bit words. */
 506         qp->s_hdrwords += 10;
 507         qp->s_hdr.u.l.grh.version_tclass_flow =
 508                 cpu_to_be32((6 << 28) |
 509                             (grh->traffic_class << 20) |
 510                             grh->flow_label);
 511         qp->s_hdr.u.l.grh.paylen =
 512                 cpu_to_be16(((qp->s_hdrwords - 12) + nwords +
 513                              SIZE_OF_CRC) << 2);
 514         /* next_hdr is defined by C8-7 in ch. 8.4.1 */
 515         qp->s_hdr.u.l.grh.next_hdr = 0x1B;
 516         qp->s_hdr.u.l.grh.hop_limit = grh->hop_limit;
 517         /* The SGID is 32-bit aligned. */
 518         qp->s_hdr.u.l.grh.sgid.global.subnet_prefix = dev->gid_prefix;
 519         qp->s_hdr.u.l.grh.sgid.global.interface_id =
 520                 ipath_layer_get_guid(dev->dd);
 521         qp->s_hdr.u.l.grh.dgid = grh->dgid;
 522 }
 523
 524 /**
 525  * ipath_do_rc_send - perform a send on an RC QP
 526  * @data: contains a pointer to the QP
 527  *
 528  * Process entries in the send work queue until credit or queue is
 529  * exhausted.  Only allow one CPU to send a packet per QP (tasklet).
 530  * Otherwise, after we drop the QP s_lock, two threads could send
 531  * packets out of order.
 532  */
 533 void ipath_do_rc_send(unsigned long data)
 534 {
 535         struct ipath_qp *qp = (struct ipath_qp *)data;
 536         struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
 537         unsigned long flags;
 538         u16 lrh0;
 539         u32 nwords;
 540         u32 extra_bytes;
 541         u32 bth0;
 542         u32 bth2;
 543         u32 pmtu = ib_mtu_enum_to_int(qp->path_mtu);
 544         struct ipath_other_headers *ohdr;
 545
 546         if (test_and_set_bit(IPATH_S_BUSY, &qp->s_flags))
 547                 goto bail;
 548
 549         if (unlikely(qp->remote_ah_attr.dlid ==
 550                      ipath_layer_get_lid(dev->dd))) {
 551                 struct ib_wc wc;
 552
 553                 /*
 554                  * Pass in an uninitialized ib_wc to be consistent with
 555                  * other places where ipath_ruc_loopback() is called.
 556                  */
 557                 ipath_ruc_loopback(qp, &wc);
 558                 goto clear;
 559         }
 560
 561         ohdr = &qp->s_hdr.u.oth;
 562         if (qp->remote_ah_attr.ah_flags & IB_AH_GRH)
 563                 ohdr = &qp->s_hdr.u.l.oth;
 564
 565 again:
 566         /* Check for a constructed packet to be sent. */
 567         if (qp->s_hdrwords != 0) {
 568                 /*
 569                  * If no PIO bufs are available, return.  An interrupt will
 570                  * call ipath_ib_piobufavail() when one is available.
 571                  */
 572                 _VERBS_INFO("h %u %p\n", qp->s_hdrwords, &qp->s_hdr);
 573                 _VERBS_INFO("d %u %p %u %p %u %u %u %u\n", qp->s_cur_size,
 574                             qp->s_cur_sge->sg_list,
 575                             qp->s_cur_sge->num_sge,
 576                             qp->s_cur_sge->sge.vaddr,
 577                             qp->s_cur_sge->sge.sge_length,
 578                             qp->s_cur_sge->sge.length,
 579                             qp->s_cur_sge->sge.m,
 580                             qp->s_cur_sge->sge.n);
 581                 if (ipath_verbs_send(dev->dd, qp->s_hdrwords,
 582                                      (u32 *) &qp->s_hdr, qp->s_cur_size,
 583                                      qp->s_cur_sge)) {
 584                         ipath_no_bufs_available(qp, dev);
 585                         goto bail;
 586                 }
 587                 dev->n_unicast_xmit++;
 588                 /* Record that we sent the packet and s_hdr is empty. */
 589                 qp->s_hdrwords = 0;
 590         }
 591
 592         /*
 593          * The lock is needed to synchronize between setting
 594          * qp->s_ack_state, resend timer, and post_send().
 595          */
 596         spin_lock_irqsave(&qp->s_lock, flags);
 597
 598         /* Sending responses has higher priority over sending requests. */
 599         if (qp->s_ack_state != OP(ACKNOWLEDGE) &&
 600             (bth0 = ipath_make_rc_ack(qp, ohdr, pmtu)) != 0)
 601                 bth2 = qp->s_ack_psn++ & IPS_PSN_MASK;
 602         else if (!ipath_make_rc_req(qp, ohdr, pmtu, &bth0, &bth2))
 603                 goto done;
 604
 605         spin_unlock_irqrestore(&qp->s_lock, flags);
 606
 607         /* Construct the header. */
 608         extra_bytes = (4 - qp->s_cur_size) & 3;
 609         nwords = (qp->s_cur_size + extra_bytes) >> 2;
 610         lrh0 = IPS_LRH_BTH;
 611         if (unlikely(qp->remote_ah_attr.ah_flags & IB_AH_GRH)) {
 612                 ipath_make_rc_grh(qp, &qp->remote_ah_attr.grh, nwords);
 613                 lrh0 = IPS_LRH_GRH;
 614         }
 615         lrh0 |= qp->remote_ah_attr.sl << 4;
 616         qp->s_hdr.lrh[0] = cpu_to_be16(lrh0);
 617         qp->s_hdr.lrh[1] = cpu_to_be16(qp->remote_ah_attr.dlid);
 618         qp->s_hdr.lrh[2] = cpu_to_be16(qp->s_hdrwords + nwords +
 619                                        SIZE_OF_CRC);
 620         qp->s_hdr.lrh[3] = cpu_to_be16(ipath_layer_get_lid(dev->dd));
 621         bth0 |= ipath_layer_get_pkey(dev->dd, qp->s_pkey_index);
 622         bth0 |= extra_bytes << 20;
 623         ohdr->bth[0] = cpu_to_be32(bth0);
 624         ohdr->bth[1] = cpu_to_be32(qp->remote_qpn);
 625         ohdr->bth[2] = cpu_to_be32(bth2);
 626
 627         /* Check for more work to do. */
 628         goto again;
 629
 630 done:
 631         spin_unlock_irqrestore(&qp->s_lock, flags);
 632 clear:
 633         clear_bit(IPATH_S_BUSY, &qp->s_flags);
 634 bail:
 635         return;
 636 }
 637
 638 static void send_rc_ack(struct ipath_qp *qp)
 639 {
 640         struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
 641         u16 lrh0;
 642         u32 bth0;
 643         struct ipath_other_headers *ohdr;
 644
 645         /* Construct the header. */
 646         ohdr = &qp->s_hdr.u.oth;
 647         lrh0 = IPS_LRH_BTH;
 648         /* header size in 32-bit words LRH+BTH+AETH = (8+12+4)/4. */
 649         qp->s_hdrwords = 6;
 650         if (unlikely(qp->remote_ah_attr.ah_flags & IB_AH_GRH)) {
 651                 ipath_make_rc_grh(qp, &qp->remote_ah_attr.grh, 0);
 652                 ohdr = &qp->s_hdr.u.l.oth;
 653                 lrh0 = IPS_LRH_GRH;
 654         }
 655         bth0 = ipath_layer_get_pkey(dev->dd, qp->s_pkey_index);
 656         ohdr->u.aeth = ipath_compute_aeth(qp);
 657         if (qp->s_ack_state >= OP(COMPARE_SWAP)) {
 658                 bth0 |= IB_OPCODE_ATOMIC_ACKNOWLEDGE << 24;
 659                 ohdr->u.at.atomic_ack_eth = cpu_to_be64(qp->s_ack_atomic);
 660                 qp->s_hdrwords += sizeof(ohdr->u.at.atomic_ack_eth) / 4;
 661         }
 662         else
 663                 bth0 |= OP(ACKNOWLEDGE) << 24;
 664         lrh0 |= qp->remote_ah_attr.sl << 4;
 665         qp->s_hdr.lrh[0] = cpu_to_be16(lrh0);
 666         qp->s_hdr.lrh[1] = cpu_to_be16(qp->remote_ah_attr.dlid);
 667         qp->s_hdr.lrh[2] = cpu_to_be16(qp->s_hdrwords + SIZE_OF_CRC);
 668         qp->s_hdr.lrh[3] = cpu_to_be16(ipath_layer_get_lid(dev->dd));
 669         ohdr->bth[0] = cpu_to_be32(bth0);
 670         ohdr->bth[1] = cpu_to_be32(qp->remote_qpn);
 671         ohdr->bth[2] = cpu_to_be32(qp->s_ack_psn & IPS_PSN_MASK);
 672
 673         /*
 674          * If we can send the ACK, clear the ACK state.
 675          */
 676         if (ipath_verbs_send(dev->dd, qp->s_hdrwords, (u32 *) &qp->s_hdr,
 677                              0, NULL) == 0) {
 678                 qp->s_ack_state = OP(ACKNOWLEDGE);
 679                 dev->n_rc_qacks++;
 680                 dev->n_unicast_xmit++;
 681         }
 682 }
 683
 684 /**
 685  * ipath_restart_rc - back up requester to resend the last un-ACKed request
 686  * @qp: the QP to restart
 687  * @psn: packet sequence number for the request
 688  * @wc: the work completion request
 689  *
 690  * The QP s_lock should be held.
 691  */
 692 void ipath_restart_rc(struct ipath_qp *qp, u32 psn, struct ib_wc *wc)
 693 {
 694         struct ipath_swqe *wqe = get_swqe_ptr(qp, qp->s_last);
 695         struct ipath_ibdev *dev;
 696         u32 n;
 697
 698         /*
 699          * If there are no requests pending, we are done.
 700          */
 701         if (ipath_cmp24(psn, qp->s_next_psn) >= 0 ||
 702             qp->s_last == qp->s_tail)
 703                 goto done;
 704
 705         if (qp->s_retry == 0) {
 706                 wc->wr_id = wqe->wr.wr_id;
 707                 wc->status = IB_WC_RETRY_EXC_ERR;
 708                 wc->opcode = ib_ipath_wc_opcode[wqe->wr.opcode];
 709                 wc->vendor_err = 0;
 710                 wc->byte_len = 0;
 711                 wc->qp_num = qp->ibqp.qp_num;
 712                 wc->src_qp = qp->remote_qpn;
 713                 wc->pkey_index = 0;
 714                 wc->slid = qp->remote_ah_attr.dlid;
 715                 wc->sl = qp->remote_ah_attr.sl;
 716                 wc->dlid_path_bits = 0;
 717                 wc->port_num = 0;
 718                 ipath_sqerror_qp(qp, wc);
 719                 goto bail;
 720         }
 721         qp->s_retry--;
 722
 723         /*
 724          * Remove the QP from the timeout queue.
 725          * Note: it may already have been removed by ipath_ib_timer().
 726          */
 727         dev = to_idev(qp->ibqp.device);
 728         spin_lock(&dev->pending_lock);
 729         if (qp->timerwait.next != LIST_POISON1)
 730                 list_del(&qp->timerwait);
 731         spin_unlock(&dev->pending_lock);
 732
 733         if (wqe->wr.opcode == IB_WR_RDMA_READ)
 734                 dev->n_rc_resends++;
 735         else
 736                 dev->n_rc_resends += (int)qp->s_psn - (int)psn;
 737
 738         /*
 739          * If we are starting the request from the beginning, let the normal
 740          * send code handle initialization.
 741          */
 742         qp->s_cur = qp->s_last;
 743         if (ipath_cmp24(psn, wqe->psn) <= 0) {
 744                 qp->s_state = OP(SEND_LAST);
 745                 qp->s_psn = wqe->psn;
 746         } else {
 747                 n = qp->s_cur;
 748                 for (;;) {
 749                         if (++n == qp->s_size)
 750                                 n = 0;
 751                         if (n == qp->s_tail) {
 752                                 if (ipath_cmp24(psn, qp->s_next_psn) >= 0) {
 753                                         qp->s_cur = n;
 754                                         wqe = get_swqe_ptr(qp, n);
 755                                 }
 756                                 break;
 757                         }
 758                         wqe = get_swqe_ptr(qp, n);
 759                         if (ipath_cmp24(psn, wqe->psn) < 0)
 760                                 break;
 761                         qp->s_cur = n;
 762                 }
 763                 qp->s_psn = psn;
 764
 765                 /*
 766                  * Reset the state to restart in the middle of a request.
 767                  * Don't change the s_sge, s_cur_sge, or s_cur_size.
 768                  * See ipath_do_rc_send().
 769                  */
 770                 switch (wqe->wr.opcode) {
 771                 case IB_WR_SEND:
 772                 case IB_WR_SEND_WITH_IMM:
 773                         qp->s_state = OP(RDMA_READ_RESPONSE_FIRST);
 774                         break;
 775
 776                 case IB_WR_RDMA_WRITE:
 777                 case IB_WR_RDMA_WRITE_WITH_IMM:
 778                         qp->s_state = OP(RDMA_READ_RESPONSE_LAST);
 779                         break;
 780
 781                 case IB_WR_RDMA_READ:
 782                         qp->s_state =
 783                                 OP(RDMA_READ_RESPONSE_MIDDLE);
 784                         break;
 785
 786                 default:
 787                         /*
 788                          * This case shouldn't happen since its only
 789                          * one PSN per req.
 790                          */
 791                         qp->s_state = OP(SEND_LAST);
 792                 }
 793         }
 794
 795 done:
 796         tasklet_hi_schedule(&qp->s_task);
 797
 798 bail:
 799         return;
 800 }
 801
 802 /**
 803  * reset_psn - reset the QP state to send starting from PSN
 804  * @qp: the QP
 805  * @psn: the packet sequence number to restart at
 806  *
 807  * This is called from ipath_rc_rcv() to process an incoming RC ACK
 808  * for the given QP.
 809  * Called at interrupt level with the QP s_lock held.
 810  */
 811 static void reset_psn(struct ipath_qp *qp, u32 psn)
 812 {
 813         struct ipath_swqe *wqe;
 814         u32 n;
 815
 816         n = qp->s_cur;
 817         wqe = get_swqe_ptr(qp, n);
 818         for (;;) {
 819                 if (++n == qp->s_size)
 820                         n = 0;
 821                 if (n == qp->s_tail) {
 822                         if (ipath_cmp24(psn, qp->s_next_psn) >= 0) {
 823                                 qp->s_cur = n;
 824                                 wqe = get_swqe_ptr(qp, n);
 825                         }
 826                         break;
 827                 }
 828                 wqe = get_swqe_ptr(qp, n);
 829                 if (ipath_cmp24(psn, wqe->psn) < 0)
 830                         break;
 831                 qp->s_cur = n;
 832         }
 833         qp->s_psn = psn;
 834
 835         /*
 836          * Set the state to restart in the middle of a
 837          * request.  Don't change the s_sge, s_cur_sge, or
 838          * s_cur_size.  See ipath_do_rc_send().
 839          */
 840         switch (wqe->wr.opcode) {
 841         case IB_WR_SEND:
 842         case IB_WR_SEND_WITH_IMM:
 843                 qp->s_state = OP(RDMA_READ_RESPONSE_FIRST);
 844                 break;
 845
 846         case IB_WR_RDMA_WRITE:
 847         case IB_WR_RDMA_WRITE_WITH_IMM:
 848                 qp->s_state = OP(RDMA_READ_RESPONSE_LAST);
 849                 break;
 850
 851         case IB_WR_RDMA_READ:
 852                 qp->s_state = OP(RDMA_READ_RESPONSE_MIDDLE);
 853                 break;
 854
 855         default:
 856                 /*
 857                  * This case shouldn't happen since its only
 858                  * one PSN per req.
 859                  */
 860                 qp->s_state = OP(SEND_LAST);
 861         }
 862 }
 863
 864 /**
 865  * do_rc_ack - process an incoming RC ACK
 866  * @qp: the QP the ACK came in on
 867  * @psn: the packet sequence number of the ACK
 868  * @opcode: the opcode of the request that resulted in the ACK
 869  *
 870  * This is called from ipath_rc_rcv() to process an incoming RC ACK
 871  * for the given QP.
 872  * Called at interrupt level with the QP s_lock held.
 873  * Returns 1 if OK, 0 if current operation should be aborted (NAK).
 874  */
 875 static int do_rc_ack(struct ipath_qp *qp, u32 aeth, u32 psn, int opcode)
 876 {
 877         struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
 878         struct ib_wc wc;
 879         struct ipath_swqe *wqe;
 880         int ret = 0;
 881
 882         /*
 883          * Remove the QP from the timeout queue (or RNR timeout queue).
 884          * If ipath_ib_timer() has already removed it,
 885          * it's OK since we hold the QP s_lock and ipath_restart_rc()
 886          * just won't find anything to restart if we ACK everything.
 887          */
 888         spin_lock(&dev->pending_lock);
 889         if (qp->timerwait.next != LIST_POISON1)
 890                 list_del(&qp->timerwait);
 891         spin_unlock(&dev->pending_lock);
 892
 893         /*
 894          * Note that NAKs implicitly ACK outstanding SEND and RDMA write
 895          * requests and implicitly NAK RDMA read and atomic requests issued
 896          * before the NAK'ed request.  The MSN won't include the NAK'ed
 897          * request but will include an ACK'ed request(s).
 898          */
 899         wqe = get_swqe_ptr(qp, qp->s_last);
 900
 901         /* Nothing is pending to ACK/NAK. */
 902         if (qp->s_last == qp->s_tail)
 903                 goto bail;
 904
 905         /*
 906          * The MSN might be for a later WQE than the PSN indicates so
 907          * only complete WQEs that the PSN finishes.
 908          */
 909         while (ipath_cmp24(psn, wqe->lpsn) >= 0) {
 910                 /* If we are ACKing a WQE, the MSN should be >= the SSN. */
 911                 if (ipath_cmp24(aeth, wqe->ssn) < 0)
 912                         break;
 913                 /*
 914                  * If this request is a RDMA read or atomic, and the ACK is
 915                  * for a later operation, this ACK NAKs the RDMA read or
 916                  * atomic.  In other words, only a RDMA_READ_LAST or ONLY
 917                  * can ACK a RDMA read and likewise for atomic ops.  Note
 918                  * that the NAK case can only happen if relaxed ordering is
 919                  * used and requests are sent after an RDMA read or atomic
 920                  * is sent but before the response is received.
 921                  */
 922                 if ((wqe->wr.opcode == IB_WR_RDMA_READ &&
 923                      opcode != OP(RDMA_READ_RESPONSE_LAST)) ||
 924                     ((wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
 925                       wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) &&
 926                      (opcode != OP(ATOMIC_ACKNOWLEDGE) ||
 927                       ipath_cmp24(wqe->psn, psn) != 0))) {
 928                         /*
 929                          * The last valid PSN seen is the previous
 930                          * request's.
 931                          */
 932                         qp->s_last_psn = wqe->psn - 1;
 933                         /* Retry this request. */
 934                         ipath_restart_rc(qp, wqe->psn, &wc);
 935                         /*
 936                          * No need to process the ACK/NAK since we are
 937                          * restarting an earlier request.
 938                          */
 939                         goto bail;
 940                 }
 941                 /* Post a send completion queue entry if requested. */
 942                 if (!test_bit(IPATH_S_SIGNAL_REQ_WR, &qp->s_flags) ||
 943                     (wqe->wr.send_flags & IB_SEND_SIGNALED)) {
 944                         wc.wr_id = wqe->wr.wr_id;
 945                         wc.status = IB_WC_SUCCESS;
 946                         wc.opcode = ib_ipath_wc_opcode[wqe->wr.opcode];
 947                         wc.vendor_err = 0;
 948                         wc.byte_len = wqe->length;
 949                         wc.qp_num = qp->ibqp.qp_num;
 950                         wc.src_qp = qp->remote_qpn;
 951                         wc.pkey_index = 0;
 952                         wc.slid = qp->remote_ah_attr.dlid;
 953                         wc.sl = qp->remote_ah_attr.sl;
 954                         wc.dlid_path_bits = 0;
 955                         wc.port_num = 0;
 956                         ipath_cq_enter(to_icq(qp->ibqp.send_cq), &wc, 0);
 957                 }
 958                 qp->s_retry = qp->s_retry_cnt;
 959                 /*
 960                  * If we are completing a request which is in the process of
 961                  * being resent, we can stop resending it since we know the
 962                  * responder has already seen it.
 963                  */
 964                 if (qp->s_last == qp->s_cur) {
 965                         if (++qp->s_cur >= qp->s_size)
 966                                 qp->s_cur = 0;
 967                         wqe = get_swqe_ptr(qp, qp->s_cur);
 968                         qp->s_state = OP(SEND_LAST);
 969                         qp->s_psn = wqe->psn;
 970                 }
 971                 if (++qp->s_last >= qp->s_size)
 972                         qp->s_last = 0;
 973                 wqe = get_swqe_ptr(qp, qp->s_last);
 974                 if (qp->s_last == qp->s_tail)
 975                         break;
 976         }
 977
 978         switch (aeth >> 29) {
 979         case 0:         /* ACK */
 980                 dev->n_rc_acks++;
 981                 /* If this is a partial ACK, reset the retransmit timer. */
 982                 if (qp->s_last != qp->s_tail) {
 983                         spin_lock(&dev->pending_lock);
 984                         list_add_tail(&qp->timerwait,
 985                                       &dev->pending[dev->pending_index]);
 986                         spin_unlock(&dev->pending_lock);
 987                 }
 988                 ipath_get_credit(qp, aeth);
 989                 qp->s_rnr_retry = qp->s_rnr_retry_cnt;
 990                 qp->s_retry = qp->s_retry_cnt;
 991                 qp->s_last_psn = psn;
 992                 ret = 1;
 993                 goto bail;
 994
 995         case 1:         /* RNR NAK */
 996                 dev->n_rnr_naks++;
 997                 if (qp->s_rnr_retry == 0) {
 998                         if (qp->s_last == qp->s_tail)
 999                                 goto bail;
1000
1001                         wc.status = IB_WC_RNR_RETRY_EXC_ERR;
1002                         goto class_b;
1003                 }
1004                 if (qp->s_rnr_retry_cnt < 7)
1005                         qp->s_rnr_retry--;
1006                 if (qp->s_last == qp->s_tail)
1007                         goto bail;
1008
1009                 /* The last valid PSN seen is the previous request's. */
1010                 qp->s_last_psn = wqe->psn - 1;
1011
1012                 dev->n_rc_resends += (int)qp->s_psn - (int)psn;
1013
1014                 /*
1015                  * If we are starting the request from the beginning, let
1016                  * the normal send code handle initialization.
1017                  */
1018                 qp->s_cur = qp->s_last;
1019                 wqe = get_swqe_ptr(qp, qp->s_cur);
1020                 if (ipath_cmp24(psn, wqe->psn) <= 0) {
1021                         qp->s_state = OP(SEND_LAST);
1022                         qp->s_psn = wqe->psn;
1023                 } else
1024                         reset_psn(qp, psn);
1025
1026                 qp->s_rnr_timeout =
1027                         ib_ipath_rnr_table[(aeth >> IPS_AETH_CREDIT_SHIFT) &
1028                                            IPS_AETH_CREDIT_MASK];
1029                 ipath_insert_rnr_queue(qp);
1030                 goto bail;
1031
1032         case 3:         /* NAK */
1033                 /* The last valid PSN seen is the previous request's. */
1034                 if (qp->s_last != qp->s_tail)
1035                         qp->s_last_psn = wqe->psn - 1;
1036                 switch ((aeth >> IPS_AETH_CREDIT_SHIFT) &
1037                         IPS_AETH_CREDIT_MASK) {
1038                 case 0: /* PSN sequence error */
1039                         dev->n_seq_naks++;
1040                         /*
1041                          * Back up to the responder's expected PSN.  XXX
1042                          * Note that we might get a NAK in the middle of an
1043                          * RDMA READ response which terminates the RDMA
1044                          * READ.
1045                          */
1046                         if (qp->s_last == qp->s_tail)
1047                                 break;
1048
1049                         if (ipath_cmp24(psn, wqe->psn) < 0)
1050                                 break;
1051
1052                         /* Retry the request. */
1053                         ipath_restart_rc(qp, psn, &wc);
1054                         break;
1055
1056                 case 1: /* Invalid Request */
1057                         wc.status = IB_WC_REM_INV_REQ_ERR;
1058                         dev->n_other_naks++;
1059                         goto class_b;
1060
1061                 case 2: /* Remote Access Error */
1062                         wc.status = IB_WC_REM_ACCESS_ERR;
1063                         dev->n_other_naks++;
1064                         goto class_b;
1065
1066                 case 3: /* Remote Operation Error */
1067                         wc.status = IB_WC_REM_OP_ERR;
1068                         dev->n_other_naks++;
1069                 class_b:
1070                         wc.wr_id = wqe->wr.wr_id;
1071                         wc.opcode = ib_ipath_wc_opcode[wqe->wr.opcode];
1072                         wc.vendor_err = 0;
1073                         wc.byte_len = 0;
1074                         wc.qp_num = qp->ibqp.qp_num;
1075                         wc.src_qp = qp->remote_qpn;
1076                         wc.pkey_index = 0;
1077                         wc.slid = qp->remote_ah_attr.dlid;
1078                         wc.sl = qp->remote_ah_attr.sl;
1079                         wc.dlid_path_bits = 0;
1080                         wc.port_num = 0;
1081                         ipath_sqerror_qp(qp, &wc);
1082                         break;
1083
1084                 default:
1085                         /* Ignore other reserved NAK error codes */
1086                         goto reserved;
1087                 }
1088                 qp->s_rnr_retry = qp->s_rnr_retry_cnt;
1089                 goto bail;
1090
1091         default:                /* 2: reserved */
1092         reserved:
1093                 /* Ignore reserved NAK codes. */
1094                 goto bail;
1095         }
1096
1097 bail:
1098         return ret;
1099 }
1100
1101 /**
1102  * ipath_rc_rcv_resp - process an incoming RC response packet
1103  * @dev: the device this packet came in on
1104  * @ohdr: the other headers for this packet
1105  * @data: the packet data
1106  * @tlen: the packet length
1107  * @qp: the QP for this packet
1108  * @opcode: the opcode for this packet
1109  * @psn: the packet sequence number for this packet
1110  * @hdrsize: the header length
1111  * @pmtu: the path MTU
1112  * @header_in_data: true if part of the header data is in the data buffer
1113  *
1114  * This is called from ipath_rc_rcv() to process an incoming RC response
1115  * packet for the given QP.
1116  * Called at interrupt level.
1117  */
1118 static inline void ipath_rc_rcv_resp(struct ipath_ibdev *dev,
1119                                      struct ipath_other_headers *ohdr,
1120                                      void *data, u32 tlen,
1121                                      struct ipath_qp *qp,
1122                                      u32 opcode,
1123                                      u32 psn, u32 hdrsize, u32 pmtu,
1124                                      int header_in_data)
1125 {
1126         unsigned long flags;
1127         struct ib_wc wc;
1128         int diff;
1129         u32 pad;
1130         u32 aeth;
1131
1132         spin_lock_irqsave(&qp->s_lock, flags);
1133
1134         /* Ignore invalid responses. */
1135         if (ipath_cmp24(psn, qp->s_next_psn) >= 0)
1136                 goto ack_done;
1137
1138         /* Ignore duplicate responses. */
1139         diff = ipath_cmp24(psn, qp->s_last_psn);
1140         if (unlikely(diff <= 0)) {
1141                 /* Update credits for "ghost" ACKs */
1142                 if (diff == 0 && opcode == OP(ACKNOWLEDGE)) {
1143                         if (!header_in_data)
1144                                 aeth = be32_to_cpu(ohdr->u.aeth);
1145                         else {
1146                                 aeth = be32_to_cpu(((__be32 *) data)[0]);
1147                                 data += sizeof(__be32);
1148                         }
1149                         if ((aeth >> 29) == 0)
1150                                 ipath_get_credit(qp, aeth);
1151                 }
1152                 goto ack_done;
1153         }
1154
1155         switch (opcode) {
1156         case OP(ACKNOWLEDGE):
1157         case OP(ATOMIC_ACKNOWLEDGE):
1158         case OP(RDMA_READ_RESPONSE_FIRST):
1159                 if (!header_in_data)
1160                         aeth = be32_to_cpu(ohdr->u.aeth);
1161                 else {
1162                         aeth = be32_to_cpu(((__be32 *) data)[0]);
1163                         data += sizeof(__be32);
1164                 }
1165                 if (opcode == OP(ATOMIC_ACKNOWLEDGE))
1166                         *(u64 *) qp->s_sge.sge.vaddr = *(u64 *) data;
1167                 if (!do_rc_ack(qp, aeth, psn, opcode) ||
1168                     opcode != OP(RDMA_READ_RESPONSE_FIRST))
1169                         goto ack_done;
1170                 hdrsize += 4;
1171                 /*
1172                  * do_rc_ack() has already checked the PSN so skip
1173                  * the sequence check.
1174                  */
1175                 goto rdma_read;
1176
1177         case OP(RDMA_READ_RESPONSE_MIDDLE):
1178                 /* no AETH, no ACK */
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         rdma_read:
1185         if (unlikely(qp->s_state != OP(RDMA_READ_REQUEST)))
1186                 goto ack_done;
1187         if (unlikely(tlen != (hdrsize + pmtu + 4)))
1188                 goto ack_done;
1189         if (unlikely(pmtu >= qp->s_len))
1190                 goto ack_done;
1191         /* We got a response so update the timeout. */
1192         if (unlikely(qp->s_last == qp->s_tail ||
1193                      get_swqe_ptr(qp, qp->s_last)->wr.opcode !=
1194                      IB_WR_RDMA_READ))
1195                 goto ack_done;
1196         spin_lock(&dev->pending_lock);
1197         if (qp->s_rnr_timeout == 0 &&
1198             qp->timerwait.next != LIST_POISON1)
1199                 list_move_tail(&qp->timerwait,
1200                                &dev->pending[dev->pending_index]);
1201         spin_unlock(&dev->pending_lock);
1202         /*
1203          * Update the RDMA receive state but do the copy w/o holding the
1204          * locks and blocking interrupts.  XXX Yet another place that
1205          * affects relaxed RDMA order since we don't want s_sge modified.
1206          */
1207         qp->s_len -= pmtu;
1208         qp->s_last_psn = psn;
1209         spin_unlock_irqrestore(&qp->s_lock, flags);
1210         ipath_copy_sge(&qp->s_sge, data, pmtu);
1211         goto bail;
1212
1213         case OP(RDMA_READ_RESPONSE_LAST):
1214                 /* ACKs READ req. */
1215                 if (unlikely(ipath_cmp24(psn, qp->s_last_psn + 1))) {
1216                         dev->n_rdma_seq++;
1217                         ipath_restart_rc(qp, qp->s_last_psn + 1, &wc);
1218                         goto ack_done;
1219                 }
1220                 /* FALLTHROUGH */
1221         case OP(RDMA_READ_RESPONSE_ONLY):
1222                 if (unlikely(qp->s_state != OP(RDMA_READ_REQUEST)))
1223                         goto ack_done;
1224                 /*
1225                  * Get the number of bytes the message was padded by.
1226                  */
1227                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1228                 /*
1229                  * Check that the data size is >= 1 && <= pmtu.
1230                  * Remember to account for the AETH header (4) and
1231                  * ICRC (4).
1232                  */
1233                 if (unlikely(tlen <= (hdrsize + pad + 8))) {
1234                         /*
1235                          * XXX Need to generate an error CQ
1236                          * entry.
1237                          */
1238                         goto ack_done;
1239                 }
1240                 tlen -= hdrsize + pad + 8;
1241                 if (unlikely(tlen != qp->s_len)) {
1242                         /*
1243                          * XXX Need to generate an error CQ
1244                          * entry.
1245                          */
1246                         goto ack_done;
1247                 }
1248                 if (!header_in_data)
1249                         aeth = be32_to_cpu(ohdr->u.aeth);
1250                 else {
1251                         aeth = be32_to_cpu(((__be32 *) data)[0]);
1252                         data += sizeof(__be32);
1253                 }
1254                 ipath_copy_sge(&qp->s_sge, data, tlen);
1255                 if (do_rc_ack(qp, aeth, psn, OP(RDMA_READ_RESPONSE_LAST))) {
1256                         /*
1257                          * Change the state so we contimue
1258                          * processing new requests.
1259                          */
1260                         qp->s_state = OP(SEND_LAST);
1261                 }
1262                 goto ack_done;
1263         }
1264
1265 ack_done:
1266         spin_unlock_irqrestore(&qp->s_lock, flags);
1267 bail:
1268         return;
1269 }
1270
1271 /**
1272  * ipath_rc_rcv_error - process an incoming duplicate or error RC packet
1273  * @dev: the device this packet came in on
1274  * @ohdr: the other headers for this packet
1275  * @data: the packet data
1276  * @qp: the QP for this packet
1277  * @opcode: the opcode for this packet
1278  * @psn: the packet sequence number for this packet
1279  * @diff: the difference between the PSN and the expected PSN
1280  * @header_in_data: true if part of the header data is in the data buffer
1281  *
1282  * This is called from ipath_rc_rcv() to process an unexpected
1283  * incoming RC packet for the given QP.
1284  * Called at interrupt level.
1285  * Return 1 if no more processing is needed; otherwise return 0 to
1286  * schedule a response to be sent and the s_lock unlocked.
1287  */
1288 static inline int ipath_rc_rcv_error(struct ipath_ibdev *dev,
1289                                      struct ipath_other_headers *ohdr,
1290                                      void *data,
1291                                      struct ipath_qp *qp,
1292                                      u32 opcode,
1293                                      u32 psn,
1294                                      int diff,
1295                                      int header_in_data)
1296 {
1297         struct ib_reth *reth;
1298
1299         if (diff > 0) {
1300                 /*
1301                  * Packet sequence error.
1302                  * A NAK will ACK earlier sends and RDMA writes.
1303                  * Don't queue the NAK if a RDMA read, atomic, or
1304                  * NAK is pending though.
1305                  */
1306                 spin_lock(&qp->s_lock);
1307                 if ((qp->s_ack_state >= OP(RDMA_READ_REQUEST) &&
1308                      qp->s_ack_state != IB_OPCODE_ACKNOWLEDGE) ||
1309                     qp->s_nak_state != 0) {
1310                         spin_unlock(&qp->s_lock);
1311                         goto done;
1312                 }
1313                 qp->s_ack_state = OP(SEND_ONLY);
1314                 qp->s_nak_state = IB_NAK_PSN_ERROR;
1315                 /* Use the expected PSN. */
1316                 qp->s_ack_psn = qp->r_psn;
1317                 goto resched;
1318         }
1319
1320         /*
1321          * Handle a duplicate request.  Don't re-execute SEND, RDMA
1322          * write or atomic op.  Don't NAK errors, just silently drop
1323          * the duplicate request.  Note that r_sge, r_len, and
1324          * r_rcv_len may be in use so don't modify them.
1325          *
1326          * We are supposed to ACK the earliest duplicate PSN but we
1327          * can coalesce an outstanding duplicate ACK.  We have to
1328          * send the earliest so that RDMA reads can be restarted at
1329          * the requester's expected PSN.
1330          */
1331         spin_lock(&qp->s_lock);
1332         if (qp->s_ack_state != IB_OPCODE_ACKNOWLEDGE &&
1333             ipath_cmp24(psn, qp->s_ack_psn) >= 0) {
1334                 if (qp->s_ack_state < IB_OPCODE_RDMA_READ_REQUEST)
1335                         qp->s_ack_psn = psn;
1336                 spin_unlock(&qp->s_lock);
1337                 goto done;
1338         }
1339         switch (opcode) {
1340         case OP(RDMA_READ_REQUEST):
1341                 /*
1342                  * We have to be careful to not change s_rdma_sge
1343                  * while ipath_do_rc_send() is using it and not
1344                  * holding the s_lock.
1345                  */
1346                 if (qp->s_ack_state != OP(ACKNOWLEDGE) &&
1347                     qp->s_ack_state >= IB_OPCODE_RDMA_READ_REQUEST) {
1348                         spin_unlock(&qp->s_lock);
1349                         dev->n_rdma_dup_busy++;
1350                         goto done;
1351                 }
1352                 /* RETH comes after BTH */
1353                 if (!header_in_data)
1354                         reth = &ohdr->u.rc.reth;
1355                 else {
1356                         reth = (struct ib_reth *)data;
1357                         data += sizeof(*reth);
1358                 }
1359                 qp->s_rdma_len = be32_to_cpu(reth->length);
1360                 if (qp->s_rdma_len != 0) {
1361                         u32 rkey = be32_to_cpu(reth->rkey);
1362                         u64 vaddr = be64_to_cpu(reth->vaddr);
1363                         int ok;
1364
1365                         /*
1366                          * Address range must be a subset of the original
1367                          * request and start on pmtu boundaries.
1368                          */
1369                         ok = ipath_rkey_ok(dev, &qp->s_rdma_sge,
1370                                            qp->s_rdma_len, vaddr, rkey,
1371                                            IB_ACCESS_REMOTE_READ);
1372                         if (unlikely(!ok))
1373                                 goto done;
1374                 } else {
1375                         qp->s_rdma_sge.sg_list = NULL;
1376                         qp->s_rdma_sge.num_sge = 0;
1377                         qp->s_rdma_sge.sge.mr = NULL;
1378                         qp->s_rdma_sge.sge.vaddr = NULL;
1379                         qp->s_rdma_sge.sge.length = 0;
1380                         qp->s_rdma_sge.sge.sge_length = 0;
1381                 }
1382                 break;
1383
1384         case OP(COMPARE_SWAP):
1385         case OP(FETCH_ADD):
1386                 /*
1387                  * Check for the PSN of the last atomic operations
1388                  * performed and resend the result if found.
1389                  */
1390                 if ((psn & IPS_PSN_MASK) != qp->r_atomic_psn) {
1391                         spin_unlock(&qp->s_lock);
1392                         goto done;
1393                 }
1394                 qp->s_ack_atomic = qp->r_atomic_data;
1395                 break;
1396         }
1397         qp->s_ack_state = opcode;
1398         qp->s_nak_state = 0;
1399         qp->s_ack_psn = psn;
1400 resched:
1401         return 0;
1402
1403 done:
1404         return 1;
1405 }
1406
1407 /**
1408  * ipath_rc_rcv - process an incoming RC packet
1409  * @dev: the device this packet came in on
1410  * @hdr: the header of this packet
1411  * @has_grh: true if the header has a GRH
1412  * @data: the packet data
1413  * @tlen: the packet length
1414  * @qp: the QP for this packet
1415  *
1416  * This is called from ipath_qp_rcv() to process an incoming RC packet
1417  * for the given QP.
1418  * Called at interrupt level.
1419  */
1420 void ipath_rc_rcv(struct ipath_ibdev *dev, struct ipath_ib_header *hdr,
1421                   int has_grh, void *data, u32 tlen, struct ipath_qp *qp)
1422 {
1423         struct ipath_other_headers *ohdr;
1424         u32 opcode;
1425         u32 hdrsize;
1426         u32 psn;
1427         u32 pad;
1428         unsigned long flags;
1429         struct ib_wc wc;
1430         u32 pmtu = ib_mtu_enum_to_int(qp->path_mtu);
1431         int diff;
1432         struct ib_reth *reth;
1433         int header_in_data;
1434
1435         /* Check for GRH */
1436         if (!has_grh) {
1437                 ohdr = &hdr->u.oth;
1438                 hdrsize = 8 + 12;       /* LRH + BTH */
1439                 psn = be32_to_cpu(ohdr->bth[2]);
1440                 header_in_data = 0;
1441         } else {
1442                 ohdr = &hdr->u.l.oth;
1443                 hdrsize = 8 + 40 + 12;  /* LRH + GRH + BTH */
1444                 /*
1445                  * The header with GRH is 60 bytes and the core driver sets
1446                  * the eager header buffer size to 56 bytes so the last 4
1447                  * bytes of the BTH header (PSN) is in the data buffer.
1448                  */
1449                 header_in_data =
1450                         ipath_layer_get_rcvhdrentsize(dev->dd) == 16;
1451                 if (header_in_data) {
1452                         psn = be32_to_cpu(((__be32 *) data)[0]);
1453                         data += sizeof(__be32);
1454                 } else
1455                         psn = be32_to_cpu(ohdr->bth[2]);
1456         }
1457         /*
1458          * The opcode is in the low byte when its in network order
1459          * (top byte when in host order).
1460          */
1461         opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
1462
1463         /*
1464          * Process responses (ACKs) before anything else.  Note that the
1465          * packet sequence number will be for something in the send work
1466          * queue rather than the expected receive packet sequence number.
1467          * In other words, this QP is the requester.
1468          */
1469         if (opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
1470             opcode <= OP(ATOMIC_ACKNOWLEDGE)) {
1471                 ipath_rc_rcv_resp(dev, ohdr, data, tlen, qp, opcode, psn,
1472                                   hdrsize, pmtu, header_in_data);
1473                 goto bail;
1474         }
1475
1476         spin_lock_irqsave(&qp->r_rq.lock, flags);
1477
1478         /* Compute 24 bits worth of difference. */
1479         diff = ipath_cmp24(psn, qp->r_psn);
1480         if (unlikely(diff)) {
1481                 if (ipath_rc_rcv_error(dev, ohdr, data, qp, opcode,
1482                                        psn, diff, header_in_data))
1483                         goto done;
1484                 goto resched;
1485         }
1486
1487         /* Check for opcode sequence errors. */
1488         switch (qp->r_state) {
1489         case OP(SEND_FIRST):
1490         case OP(SEND_MIDDLE):
1491                 if (opcode == OP(SEND_MIDDLE) ||
1492                     opcode == OP(SEND_LAST) ||
1493                     opcode == OP(SEND_LAST_WITH_IMMEDIATE))
1494                         break;
1495         nack_inv:
1496         /*
1497          * A NAK will ACK earlier sends and RDMA writes.  Don't queue the
1498          * NAK if a RDMA read, atomic, or NAK is pending though.
1499          */
1500         spin_lock(&qp->s_lock);
1501         if (qp->s_ack_state >= OP(RDMA_READ_REQUEST) &&
1502             qp->s_ack_state != IB_OPCODE_ACKNOWLEDGE) {
1503                 spin_unlock(&qp->s_lock);
1504                 goto done;
1505         }
1506         /* XXX Flush WQEs */
1507         qp->state = IB_QPS_ERR;
1508         qp->s_ack_state = OP(SEND_ONLY);
1509         qp->s_nak_state = IB_NAK_INVALID_REQUEST;
1510         qp->s_ack_psn = qp->r_psn;
1511         goto resched;
1512
1513         case OP(RDMA_WRITE_FIRST):
1514         case OP(RDMA_WRITE_MIDDLE):
1515                 if (opcode == OP(RDMA_WRITE_MIDDLE) ||
1516                     opcode == OP(RDMA_WRITE_LAST) ||
1517                     opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
1518                         break;
1519                 goto nack_inv;
1520
1521         case OP(RDMA_READ_REQUEST):
1522         case OP(COMPARE_SWAP):
1523         case OP(FETCH_ADD):
1524                 /*
1525                  * Drop all new requests until a response has been sent.  A
1526                  * new request then ACKs the RDMA response we sent.  Relaxed
1527                  * ordering would allow new requests to be processed but we
1528                  * would need to keep a queue of rwqe's for all that are in
1529                  * progress.  Note that we can't RNR NAK this request since
1530                  * the RDMA READ or atomic response is already queued to be
1531                  * sent (unless we implement a response send queue).
1532                  */
1533                 goto done;
1534
1535         default:
1536                 if (opcode == OP(SEND_MIDDLE) ||
1537                     opcode == OP(SEND_LAST) ||
1538                     opcode == OP(SEND_LAST_WITH_IMMEDIATE) ||
1539                     opcode == OP(RDMA_WRITE_MIDDLE) ||
1540                     opcode == OP(RDMA_WRITE_LAST) ||
1541                     opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
1542                         goto nack_inv;
1543                 break;
1544         }
1545
1546         wc.imm_data = 0;
1547         wc.wc_flags = 0;
1548
1549         /* OK, process the packet. */
1550         switch (opcode) {
1551         case OP(SEND_FIRST):
1552                 if (!ipath_get_rwqe(qp, 0)) {
1553                 rnr_nak:
1554                         /*
1555                          * A RNR NAK will ACK earlier sends and RDMA writes.
1556                          * Don't queue the NAK if a RDMA read or atomic
1557                          * is pending though.
1558                          */
1559                         spin_lock(&qp->s_lock);
1560                         if (qp->s_ack_state >=
1561                             OP(RDMA_READ_REQUEST) &&
1562                             qp->s_ack_state != IB_OPCODE_ACKNOWLEDGE) {
1563                                 spin_unlock(&qp->s_lock);
1564                                 goto done;
1565                         }
1566                         qp->s_ack_state = OP(SEND_ONLY);
1567                         qp->s_nak_state = IB_RNR_NAK | qp->s_min_rnr_timer;
1568                         qp->s_ack_psn = qp->r_psn;
1569                         goto resched;
1570                 }
1571                 qp->r_rcv_len = 0;
1572                 /* FALLTHROUGH */
1573         case OP(SEND_MIDDLE):
1574         case OP(RDMA_WRITE_MIDDLE):
1575         send_middle:
1576                 /* Check for invalid length PMTU or posted rwqe len. */
1577                 if (unlikely(tlen != (hdrsize + pmtu + 4)))
1578                         goto nack_inv;
1579                 qp->r_rcv_len += pmtu;
1580                 if (unlikely(qp->r_rcv_len > qp->r_len))
1581                         goto nack_inv;
1582                 ipath_copy_sge(&qp->r_sge, data, pmtu);
1583                 break;
1584
1585         case OP(RDMA_WRITE_LAST_WITH_IMMEDIATE):
1586                 /* consume RWQE */
1587                 if (!ipath_get_rwqe(qp, 1))
1588                         goto rnr_nak;
1589                 goto send_last_imm;
1590
1591         case OP(SEND_ONLY):
1592         case OP(SEND_ONLY_WITH_IMMEDIATE):
1593                 if (!ipath_get_rwqe(qp, 0))
1594                         goto rnr_nak;
1595                 qp->r_rcv_len = 0;
1596                 if (opcode == OP(SEND_ONLY))
1597                         goto send_last;
1598                 /* FALLTHROUGH */
1599         case OP(SEND_LAST_WITH_IMMEDIATE):
1600         send_last_imm:
1601                 if (header_in_data) {
1602                         wc.imm_data = *(__be32 *) data;
1603                         data += sizeof(__be32);
1604                 } else {
1605                         /* Immediate data comes after BTH */
1606                         wc.imm_data = ohdr->u.imm_data;
1607                 }
1608                 hdrsize += 4;
1609                 wc.wc_flags = IB_WC_WITH_IMM;
1610                 /* FALLTHROUGH */
1611         case OP(SEND_LAST):
1612         case OP(RDMA_WRITE_LAST):
1613         send_last:
1614                 /* Get the number of bytes the message was padded by. */
1615                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1616                 /* Check for invalid length. */
1617                 /* XXX LAST len should be >= 1 */
1618                 if (unlikely(tlen < (hdrsize + pad + 4)))
1619                         goto nack_inv;
1620                 /* Don't count the CRC. */
1621                 tlen -= (hdrsize + pad + 4);
1622                 wc.byte_len = tlen + qp->r_rcv_len;
1623                 if (unlikely(wc.byte_len > qp->r_len))
1624                         goto nack_inv;
1625                 ipath_copy_sge(&qp->r_sge, data, tlen);
1626                 atomic_inc(&qp->msn);
1627                 if (opcode == OP(RDMA_WRITE_LAST) ||
1628                     opcode == OP(RDMA_WRITE_ONLY))
1629                         break;
1630                 wc.wr_id = qp->r_wr_id;
1631                 wc.status = IB_WC_SUCCESS;
1632                 wc.opcode = IB_WC_RECV;
1633                 wc.vendor_err = 0;
1634                 wc.qp_num = qp->ibqp.qp_num;
1635                 wc.src_qp = qp->remote_qpn;
1636                 wc.pkey_index = 0;
1637                 wc.slid = qp->remote_ah_attr.dlid;
1638                 wc.sl = qp->remote_ah_attr.sl;
1639                 wc.dlid_path_bits = 0;
1640                 wc.port_num = 0;
1641                 /* Signal completion event if the solicited bit is set. */
1642                 ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
1643                                (ohdr->bth[0] &
1644                                 __constant_cpu_to_be32(1 << 23)) != 0);
1645                 break;
1646
1647         case OP(RDMA_WRITE_FIRST):
1648         case OP(RDMA_WRITE_ONLY):
1649         case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE):
1650                 /* consume RWQE */
1651                 /* RETH comes after BTH */
1652                 if (!header_in_data)
1653                         reth = &ohdr->u.rc.reth;
1654                 else {
1655                         reth = (struct ib_reth *)data;
1656                         data += sizeof(*reth);
1657                 }
1658                 hdrsize += sizeof(*reth);
1659                 qp->r_len = be32_to_cpu(reth->length);
1660                 qp->r_rcv_len = 0;
1661                 if (qp->r_len != 0) {
1662                         u32 rkey = be32_to_cpu(reth->rkey);
1663                         u64 vaddr = be64_to_cpu(reth->vaddr);
1664                         int ok;
1665
1666                         /* Check rkey & NAK */
1667                         ok = ipath_rkey_ok(dev, &qp->r_sge,
1668                                            qp->r_len, vaddr, rkey,
1669                                            IB_ACCESS_REMOTE_WRITE);
1670                         if (unlikely(!ok)) {
1671                         nack_acc:
1672                                 /*
1673                                  * A NAK will ACK earlier sends and RDMA
1674                                  * writes.  Don't queue the NAK if a RDMA
1675                                  * read, atomic, or NAK is pending though.
1676                                  */
1677                                 spin_lock(&qp->s_lock);
1678                                 if (qp->s_ack_state >=
1679                                     OP(RDMA_READ_REQUEST) &&
1680                                     qp->s_ack_state !=
1681                                     IB_OPCODE_ACKNOWLEDGE) {
1682                                         spin_unlock(&qp->s_lock);
1683                                         goto done;
1684                                 }
1685                                 /* XXX Flush WQEs */
1686                                 qp->state = IB_QPS_ERR;
1687                                 qp->s_ack_state = OP(RDMA_WRITE_ONLY);
1688                                 qp->s_nak_state =
1689                                         IB_NAK_REMOTE_ACCESS_ERROR;
1690                                 qp->s_ack_psn = qp->r_psn;
1691                                 goto resched;
1692                         }
1693                 } else {
1694                         qp->r_sge.sg_list = NULL;
1695                         qp->r_sge.sge.mr = NULL;
1696                         qp->r_sge.sge.vaddr = NULL;
1697                         qp->r_sge.sge.length = 0;
1698                         qp->r_sge.sge.sge_length = 0;
1699                 }
1700                 if (unlikely(!(qp->qp_access_flags &
1701                                IB_ACCESS_REMOTE_WRITE)))
1702                         goto nack_acc;
1703                 if (opcode == OP(RDMA_WRITE_FIRST))
1704                         goto send_middle;
1705                 else if (opcode == OP(RDMA_WRITE_ONLY))
1706                         goto send_last;
1707                 if (!ipath_get_rwqe(qp, 1))
1708                         goto rnr_nak;
1709                 goto send_last_imm;
1710
1711         case OP(RDMA_READ_REQUEST):
1712                 /* RETH comes after BTH */
1713                 if (!header_in_data)
1714                         reth = &ohdr->u.rc.reth;
1715                 else {
1716                         reth = (struct ib_reth *)data;
1717                         data += sizeof(*reth);
1718                 }
1719                 spin_lock(&qp->s_lock);
1720                 if (qp->s_ack_state != OP(ACKNOWLEDGE) &&
1721                     qp->s_ack_state >= IB_OPCODE_RDMA_READ_REQUEST) {
1722                         spin_unlock(&qp->s_lock);
1723                         goto done;
1724                 }
1725                 qp->s_rdma_len = be32_to_cpu(reth->length);
1726                 if (qp->s_rdma_len != 0) {
1727                         u32 rkey = be32_to_cpu(reth->rkey);
1728                         u64 vaddr = be64_to_cpu(reth->vaddr);
1729                         int ok;
1730
1731                         /* Check rkey & NAK */
1732                         ok = ipath_rkey_ok(dev, &qp->s_rdma_sge,
1733                                            qp->s_rdma_len, vaddr, rkey,
1734                                            IB_ACCESS_REMOTE_READ);
1735                         if (unlikely(!ok)) {
1736                                 spin_unlock(&qp->s_lock);
1737                                 goto nack_acc;
1738                         }
1739                         /*
1740                          * Update the next expected PSN.  We add 1 later
1741                          * below, so only add the remainder here.
1742                          */
1743                         if (qp->s_rdma_len > pmtu)
1744                                 qp->r_psn += (qp->s_rdma_len - 1) / pmtu;
1745                 } else {
1746                         qp->s_rdma_sge.sg_list = NULL;
1747                         qp->s_rdma_sge.num_sge = 0;
1748                         qp->s_rdma_sge.sge.mr = NULL;
1749                         qp->s_rdma_sge.sge.vaddr = NULL;
1750                         qp->s_rdma_sge.sge.length = 0;
1751                         qp->s_rdma_sge.sge.sge_length = 0;
1752                 }
1753                 if (unlikely(!(qp->qp_access_flags &
1754                                IB_ACCESS_REMOTE_READ)))
1755                         goto nack_acc;
1756                 /*
1757                  * We need to increment the MSN here instead of when we
1758                  * finish sending the result since a duplicate request would
1759                  * increment it more than once.
1760                  */
1761                 atomic_inc(&qp->msn);
1762                 qp->s_ack_state = opcode;
1763                 qp->s_nak_state = 0;
1764                 qp->s_ack_psn = psn;
1765                 qp->r_psn++;
1766                 qp->r_state = opcode;
1767                 goto rdmadone;
1768
1769         case OP(COMPARE_SWAP):
1770         case OP(FETCH_ADD): {
1771                 struct ib_atomic_eth *ateth;
1772                 u64 vaddr;
1773                 u64 sdata;
1774                 u32 rkey;
1775
1776                 if (!header_in_data)
1777                         ateth = &ohdr->u.atomic_eth;
1778                 else {
1779                         ateth = (struct ib_atomic_eth *)data;
1780                         data += sizeof(*ateth);
1781                 }
1782                 vaddr = be64_to_cpu(ateth->vaddr);
1783                 if (unlikely(vaddr & (sizeof(u64) - 1)))
1784                         goto nack_inv;
1785                 rkey = be32_to_cpu(ateth->rkey);
1786                 /* Check rkey & NAK */
1787                 if (unlikely(!ipath_rkey_ok(dev, &qp->r_sge,
1788                                             sizeof(u64), vaddr, rkey,
1789                                             IB_ACCESS_REMOTE_ATOMIC)))
1790                         goto nack_acc;
1791                 if (unlikely(!(qp->qp_access_flags &
1792                                IB_ACCESS_REMOTE_ATOMIC)))
1793                         goto nack_acc;
1794                 /* Perform atomic OP and save result. */
1795                 sdata = be64_to_cpu(ateth->swap_data);
1796                 spin_lock(&dev->pending_lock);
1797                 qp->r_atomic_data = *(u64 *) qp->r_sge.sge.vaddr;
1798                 if (opcode == OP(FETCH_ADD))
1799                         *(u64 *) qp->r_sge.sge.vaddr =
1800                                 qp->r_atomic_data + sdata;
1801                 else if (qp->r_atomic_data ==
1802                          be64_to_cpu(ateth->compare_data))
1803                         *(u64 *) qp->r_sge.sge.vaddr = sdata;
1804                 spin_unlock(&dev->pending_lock);
1805                 atomic_inc(&qp->msn);
1806                 qp->r_atomic_psn = psn & IPS_PSN_MASK;
1807                 psn |= 1 << 31;
1808                 break;
1809         }
1810
1811         default:
1812                 /* Drop packet for unknown opcodes. */
1813                 goto done;
1814         }
1815         qp->r_psn++;
1816         qp->r_state = opcode;
1817         /* Send an ACK if requested or required. */
1818         if (psn & (1 << 31)) {
1819                 /*
1820                  * Coalesce ACKs unless there is a RDMA READ or
1821                  * ATOMIC pending.
1822                  */
1823                 spin_lock(&qp->s_lock);
1824                 if (qp->s_ack_state == OP(ACKNOWLEDGE) ||
1825                     qp->s_ack_state < IB_OPCODE_RDMA_READ_REQUEST) {
1826                         qp->s_ack_state = opcode;
1827                         qp->s_nak_state = 0;
1828                         qp->s_ack_psn = psn;
1829                         qp->s_ack_atomic = qp->r_atomic_data;
1830                         goto resched;
1831                 }
1832                 spin_unlock(&qp->s_lock);
1833         }
1834 done:
1835         spin_unlock_irqrestore(&qp->r_rq.lock, flags);
1836         goto bail;
1837
1838 resched:
1839         /*
1840          * Try to send ACK right away but not if ipath_do_rc_send() is
1841          * active.
1842          */
1843         if (qp->s_hdrwords == 0 &&
1844             (qp->s_ack_state < IB_OPCODE_RDMA_READ_REQUEST ||
1845              qp->s_ack_state >= IB_OPCODE_COMPARE_SWAP))
1846                 send_rc_ack(qp);
1847
1848 rdmadone:
1849         spin_unlock(&qp->s_lock);
1850         spin_unlock_irqrestore(&qp->r_rq.lock, flags);
1851
1852         /* Call ipath_do_rc_send() in another thread. */
1853         tasklet_hi_schedule(&qp->s_task);
1854
1855 bail:
1856         return;
1857 }