drivers/infiniband/hw/ipath/ipath_rc.c

   1 /*
   2  * Copyright (c) 2006, 2007, 2008 QLogic Corporation. All rights reserved.
   3  * Copyright (c) 2005, 2006 PathScale, Inc. All rights reserved.
   4  *
   5  * This software is available to you under a choice of one of two
   6  * licenses.  You may choose to be licensed under the terms of the GNU
   7  * General Public License (GPL) Version 2, available from the file
   8  * COPYING in the main directory of this source tree, or the
   9  * OpenIB.org BSD license below:
  10  *
  11  *     Redistribution and use in source and binary forms, with or
  12  *     without modification, are permitted provided that the following
  13  *     conditions are met:
  14  *
  15  *      - Redistributions of source code must retain the above
  16  *        copyright notice, this list of conditions and the following
  17  *        disclaimer.
  18  *
  19  *      - Redistributions in binary form must reproduce the above
  20  *        copyright notice, this list of conditions and the following
  21  *        disclaimer in the documentation and/or other materials
  22  *        provided with the distribution.
  23  *
  24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  25  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  26  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  27  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  28  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  29  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  30  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  31  * SOFTWARE.
  32  */
  33
  34 #include <linux/io.h>
  35
  36 #include "ipath_verbs.h"
  37 #include "ipath_kernel.h"
  38
  39 /* cut down ridiculously long IB macro names */
  40 #define OP(x) IB_OPCODE_RC_##x
  41
  42 static u32 restart_sge(struct ipath_sge_state *ss, struct ipath_swqe *wqe,
  43                        u32 psn, u32 pmtu)
  44 {
  45         u32 len;
  46
  47         len = ((psn - wqe->psn) & IPATH_PSN_MASK) * pmtu;
  48         ss->sge = wqe->sg_list[0];
  49         ss->sg_list = wqe->sg_list + 1;
  50         ss->num_sge = wqe->wr.num_sge;
  51         ipath_skip_sge(ss, len);
  52         return wqe->length - len;
  53 }
  54
  55 /**
  56  * ipath_init_restart- initialize the qp->s_sge after a restart
  57  * @qp: the QP who's SGE we're restarting
  58  * @wqe: the work queue to initialize the QP's SGE from
  59  *
  60  * The QP s_lock should be held and interrupts disabled.
  61  */
  62 static void ipath_init_restart(struct ipath_qp *qp, struct ipath_swqe *wqe)
  63 {
  64         struct ipath_ibdev *dev;
  65
  66         qp->s_len = restart_sge(&qp->s_sge, wqe, qp->s_psn,
  67                                 ib_mtu_enum_to_int(qp->path_mtu));
  68         dev = to_idev(qp->ibqp.device);
  69         spin_lock(&dev->pending_lock);
  70         if (list_empty(&qp->timerwait))
  71                 list_add_tail(&qp->timerwait,
  72                               &dev->pending[dev->pending_index]);
  73         spin_unlock(&dev->pending_lock);
  74 }
  75
  76 /**
  77  * ipath_make_rc_ack - construct a response packet (ACK, NAK, or RDMA read)
  78  * @qp: a pointer to the QP
  79  * @ohdr: a pointer to the IB header being constructed
  80  * @pmtu: the path MTU
  81  *
  82  * Return 1 if constructed; otherwise, return 0.
  83  * Note that we are in the responder's side of the QP context.
  84  * Note the QP s_lock must be held.
  85  */
  86 static int ipath_make_rc_ack(struct ipath_ibdev *dev, struct ipath_qp *qp,
  87                              struct ipath_other_headers *ohdr, u32 pmtu)
  88 {
  89         struct ipath_ack_entry *e;
  90         u32 hwords;
  91         u32 len;
  92         u32 bth0;
  93         u32 bth2;
  94
  95         /* Don't send an ACK if we aren't supposed to. */
  96         if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_RECV_OK))
  97                 goto bail;
  98
  99         /* header size in 32-bit words LRH+BTH = (8+12)/4. */
 100         hwords = 5;
 101
 102         switch (qp->s_ack_state) {
 103         case OP(RDMA_READ_RESPONSE_LAST):
 104         case OP(RDMA_READ_RESPONSE_ONLY):
 105         case OP(ATOMIC_ACKNOWLEDGE):
 106                 /*
 107                  * We can increment the tail pointer now that the last
 108                  * response has been sent instead of only being
 109                  * constructed.
 110                  */
 111                 if (++qp->s_tail_ack_queue > IPATH_MAX_RDMA_ATOMIC)
 112                         qp->s_tail_ack_queue = 0;
 113                 /* FALLTHROUGH */
 114         case OP(SEND_ONLY):
 115         case OP(ACKNOWLEDGE):
 116                 /* Check for no next entry in the queue. */
 117                 if (qp->r_head_ack_queue == qp->s_tail_ack_queue) {
 118                         if (qp->s_flags & IPATH_S_ACK_PENDING)
 119                                 goto normal;
 120                         qp->s_ack_state = OP(ACKNOWLEDGE);
 121                         goto bail;
 122                 }
 123
 124                 e = &qp->s_ack_queue[qp->s_tail_ack_queue];
 125                 if (e->opcode == OP(RDMA_READ_REQUEST)) {
 126                         /* Copy SGE state in case we need to resend */
 127                         qp->s_ack_rdma_sge = e->rdma_sge;
 128                         qp->s_cur_sge = &qp->s_ack_rdma_sge;
 129                         len = e->rdma_sge.sge.sge_length;
 130                         if (len > pmtu) {
 131                                 len = pmtu;
 132                                 qp->s_ack_state = OP(RDMA_READ_RESPONSE_FIRST);
 133                         } else {
 134                                 qp->s_ack_state = OP(RDMA_READ_RESPONSE_ONLY);
 135                                 e->sent = 1;
 136                         }
 137                         ohdr->u.aeth = ipath_compute_aeth(qp);
 138                         hwords++;
 139                         qp->s_ack_rdma_psn = e->psn;
 140                         bth2 = qp->s_ack_rdma_psn++ & IPATH_PSN_MASK;
 141                 } else {
 142                         /* COMPARE_SWAP or FETCH_ADD */
 143                         qp->s_cur_sge = NULL;
 144                         len = 0;
 145                         qp->s_ack_state = OP(ATOMIC_ACKNOWLEDGE);
 146                         ohdr->u.at.aeth = ipath_compute_aeth(qp);
 147                         ohdr->u.at.atomic_ack_eth[0] =
 148                                 cpu_to_be32(e->atomic_data >> 32);
 149                         ohdr->u.at.atomic_ack_eth[1] =
 150                                 cpu_to_be32(e->atomic_data);
 151                         hwords += sizeof(ohdr->u.at) / sizeof(u32);
 152                         bth2 = e->psn;
 153                         e->sent = 1;
 154                 }
 155                 bth0 = qp->s_ack_state << 24;
 156                 break;
 157
 158         case OP(RDMA_READ_RESPONSE_FIRST):
 159                 qp->s_ack_state = OP(RDMA_READ_RESPONSE_MIDDLE);
 160                 /* FALLTHROUGH */
 161         case OP(RDMA_READ_RESPONSE_MIDDLE):
 162                 len = qp->s_ack_rdma_sge.sge.sge_length;
 163                 if (len > pmtu)
 164                         len = pmtu;
 165                 else {
 166                         ohdr->u.aeth = ipath_compute_aeth(qp);
 167                         hwords++;
 168                         qp->s_ack_state = OP(RDMA_READ_RESPONSE_LAST);
 169                         qp->s_ack_queue[qp->s_tail_ack_queue].sent = 1;
 170                 }
 171                 bth0 = qp->s_ack_state << 24;
 172                 bth2 = qp->s_ack_rdma_psn++ & IPATH_PSN_MASK;
 173                 break;
 174
 175         default:
 176         normal:
 177                 /*
 178                  * Send a regular ACK.
 179                  * Set the s_ack_state so we wait until after sending
 180                  * the ACK before setting s_ack_state to ACKNOWLEDGE
 181                  * (see above).
 182                  */
 183                 qp->s_ack_state = OP(SEND_ONLY);
 184                 qp->s_flags &= ~IPATH_S_ACK_PENDING;
 185                 qp->s_cur_sge = NULL;
 186                 if (qp->s_nak_state)
 187                         ohdr->u.aeth =
 188                                 cpu_to_be32((qp->r_msn & IPATH_MSN_MASK) |
 189                                             (qp->s_nak_state <<
 190                                              IPATH_AETH_CREDIT_SHIFT));
 191                 else
 192                         ohdr->u.aeth = ipath_compute_aeth(qp);
 193                 hwords++;
 194                 len = 0;
 195                 bth0 = OP(ACKNOWLEDGE) << 24;
 196                 bth2 = qp->s_ack_psn & IPATH_PSN_MASK;
 197         }
 198         qp->s_hdrwords = hwords;
 199         qp->s_cur_size = len;
 200         ipath_make_ruc_header(dev, qp, ohdr, bth0, bth2);
 201         return 1;
 202
 203 bail:
 204         return 0;
 205 }
 206
 207 /**
 208  * ipath_make_rc_req - construct a request packet (SEND, RDMA r/w, ATOMIC)
 209  * @qp: a pointer to the QP
 210  *
 211  * Return 1 if constructed; otherwise, return 0.
 212  */
 213 int ipath_make_rc_req(struct ipath_qp *qp)
 214 {
 215         struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
 216         struct ipath_other_headers *ohdr;
 217         struct ipath_sge_state *ss;
 218         struct ipath_swqe *wqe;
 219         u32 hwords;
 220         u32 len;
 221         u32 bth0;
 222         u32 bth2;
 223         u32 pmtu = ib_mtu_enum_to_int(qp->path_mtu);
 224         char newreq;
 225         unsigned long flags;
 226         int ret = 0;
 227
 228         ohdr = &qp->s_hdr.u.oth;
 229         if (qp->remote_ah_attr.ah_flags & IB_AH_GRH)
 230                 ohdr = &qp->s_hdr.u.l.oth;
 231
 232         /*
 233          * The lock is needed to synchronize between the sending tasklet,
 234          * the receive interrupt handler, and timeout resends.
 235          */
 236         spin_lock_irqsave(&qp->s_lock, flags);
 237
 238         /* Sending responses has higher priority over sending requests. */
 239         if ((qp->r_head_ack_queue != qp->s_tail_ack_queue ||
 240              (qp->s_flags & IPATH_S_ACK_PENDING) ||
 241              qp->s_ack_state != OP(ACKNOWLEDGE)) &&
 242             ipath_make_rc_ack(dev, qp, ohdr, pmtu))
 243                 goto done;
 244
 245         if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_SEND_OK)) {
 246                 if (!(ib_ipath_state_ops[qp->state] & IPATH_FLUSH_SEND))
 247                         goto bail;
 248                 /* We are in the error state, flush the work request. */
 249                 if (qp->s_last == qp->s_head)
 250                         goto bail;
 251                 /* If DMAs are in progress, we can't flush immediately. */
 252                 if (atomic_read(&qp->s_dma_busy)) {
 253                         qp->s_flags |= IPATH_S_WAIT_DMA;
 254                         goto bail;
 255                 }
 256                 wqe = get_swqe_ptr(qp, qp->s_last);
 257                 ipath_send_complete(qp, wqe, IB_WC_WR_FLUSH_ERR);
 258                 goto done;
 259         }
 260
 261         /* Leave BUSY set until RNR timeout. */
 262         if (qp->s_rnr_timeout) {
 263                 qp->s_flags |= IPATH_S_WAITING;
 264                 goto bail;
 265         }
 266
 267         /* header size in 32-bit words LRH+BTH = (8+12)/4. */
 268         hwords = 5;
 269         bth0 = 1 << 22; /* Set M bit */
 270
 271         /* Send a request. */
 272         wqe = get_swqe_ptr(qp, qp->s_cur);
 273         switch (qp->s_state) {
 274         default:
 275                 if (!(ib_ipath_state_ops[qp->state] &
 276                     IPATH_PROCESS_NEXT_SEND_OK))
 277                         goto bail;
 278                 /*
 279                  * Resend an old request or start a new one.
 280                  *
 281                  * We keep track of the current SWQE so that
 282                  * we don't reset the "furthest progress" state
 283                  * if we need to back up.
 284                  */
 285                 newreq = 0;
 286                 if (qp->s_cur == qp->s_tail) {
 287                         /* Check if send work queue is empty. */
 288                         if (qp->s_tail == qp->s_head)
 289                                 goto bail;
 290                         /*
 291                          * If a fence is requested, wait for previous
 292                          * RDMA read and atomic operations to finish.
 293                          */
 294                         if ((wqe->wr.send_flags & IB_SEND_FENCE) &&
 295                             qp->s_num_rd_atomic) {
 296                                 qp->s_flags |= IPATH_S_FENCE_PENDING;
 297                                 goto bail;
 298                         }
 299                         wqe->psn = qp->s_next_psn;
 300                         newreq = 1;
 301                 }
 302                 /*
 303                  * Note that we have to be careful not to modify the
 304                  * original work request since we may need to resend
 305                  * it.
 306                  */
 307                 len = wqe->length;
 308                 ss = &qp->s_sge;
 309                 bth2 = 0;
 310                 switch (wqe->wr.opcode) {
 311                 case IB_WR_SEND:
 312                 case IB_WR_SEND_WITH_IMM:
 313                         /* If no credit, return. */
 314                         if (qp->s_lsn != (u32) -1 &&
 315                             ipath_cmp24(wqe->ssn, qp->s_lsn + 1) > 0) {
 316                                 qp->s_flags |= IPATH_S_WAIT_SSN_CREDIT;
 317                                 goto bail;
 318                         }
 319                         wqe->lpsn = wqe->psn;
 320                         if (len > pmtu) {
 321                                 wqe->lpsn += (len - 1) / pmtu;
 322                                 qp->s_state = OP(SEND_FIRST);
 323                                 len = pmtu;
 324                                 break;
 325                         }
 326                         if (wqe->wr.opcode == IB_WR_SEND)
 327                                 qp->s_state = OP(SEND_ONLY);
 328                         else {
 329                                 qp->s_state = OP(SEND_ONLY_WITH_IMMEDIATE);
 330                                 /* Immediate data comes after the BTH */
 331                                 ohdr->u.imm_data = wqe->wr.ex.imm_data;
 332                                 hwords += 1;
 333                         }
 334                         if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 335                                 bth0 |= 1 << 23;
 336                         bth2 = 1 << 31; /* Request ACK. */
 337                         if (++qp->s_cur == qp->s_size)
 338                                 qp->s_cur = 0;
 339                         break;
 340
 341                 case IB_WR_RDMA_WRITE:
 342                         if (newreq && qp->s_lsn != (u32) -1)
 343                                 qp->s_lsn++;
 344                         /* FALLTHROUGH */
 345                 case IB_WR_RDMA_WRITE_WITH_IMM:
 346                         /* If no credit, return. */
 347                         if (qp->s_lsn != (u32) -1 &&
 348                             ipath_cmp24(wqe->ssn, qp->s_lsn + 1) > 0) {
 349                                 qp->s_flags |= IPATH_S_WAIT_SSN_CREDIT;
 350                                 goto bail;
 351                         }
 352                         ohdr->u.rc.reth.vaddr =
 353                                 cpu_to_be64(wqe->wr.wr.rdma.remote_addr);
 354                         ohdr->u.rc.reth.rkey =
 355                                 cpu_to_be32(wqe->wr.wr.rdma.rkey);
 356                         ohdr->u.rc.reth.length = cpu_to_be32(len);
 357                         hwords += sizeof(struct ib_reth) / sizeof(u32);
 358                         wqe->lpsn = wqe->psn;
 359                         if (len > pmtu) {
 360                                 wqe->lpsn += (len - 1) / pmtu;
 361                                 qp->s_state = OP(RDMA_WRITE_FIRST);
 362                                 len = pmtu;
 363                                 break;
 364                         }
 365                         if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
 366                                 qp->s_state = OP(RDMA_WRITE_ONLY);
 367                         else {
 368                                 qp->s_state =
 369                                         OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE);
 370                                 /* Immediate data comes after RETH */
 371                                 ohdr->u.rc.imm_data = wqe->wr.ex.imm_data;
 372                                 hwords += 1;
 373                                 if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 374                                         bth0 |= 1 << 23;
 375                         }
 376                         bth2 = 1 << 31; /* Request ACK. */
 377                         if (++qp->s_cur == qp->s_size)
 378                                 qp->s_cur = 0;
 379                         break;
 380
 381                 case IB_WR_RDMA_READ:
 382                         /*
 383                          * Don't allow more operations to be started
 384                          * than the QP limits allow.
 385                          */
 386                         if (newreq) {
 387                                 if (qp->s_num_rd_atomic >=
 388                                     qp->s_max_rd_atomic) {
 389                                         qp->s_flags |= IPATH_S_RDMAR_PENDING;
 390                                         goto bail;
 391                                 }
 392                                 qp->s_num_rd_atomic++;
 393                                 if (qp->s_lsn != (u32) -1)
 394                                         qp->s_lsn++;
 395                                 /*
 396                                  * Adjust s_next_psn to count the
 397                                  * expected number of responses.
 398                                  */
 399                                 if (len > pmtu)
 400                                         qp->s_next_psn += (len - 1) / pmtu;
 401                                 wqe->lpsn = qp->s_next_psn++;
 402                         }
 403                         ohdr->u.rc.reth.vaddr =
 404                                 cpu_to_be64(wqe->wr.wr.rdma.remote_addr);
 405                         ohdr->u.rc.reth.rkey =
 406                                 cpu_to_be32(wqe->wr.wr.rdma.rkey);
 407                         ohdr->u.rc.reth.length = cpu_to_be32(len);
 408                         qp->s_state = OP(RDMA_READ_REQUEST);
 409                         hwords += sizeof(ohdr->u.rc.reth) / sizeof(u32);
 410                         ss = NULL;
 411                         len = 0;
 412                         if (++qp->s_cur == qp->s_size)
 413                                 qp->s_cur = 0;
 414                         break;
 415
 416                 case IB_WR_ATOMIC_CMP_AND_SWP:
 417                 case IB_WR_ATOMIC_FETCH_AND_ADD:
 418                         /*
 419                          * Don't allow more operations to be started
 420                          * than the QP limits allow.
 421                          */
 422                         if (newreq) {
 423                                 if (qp->s_num_rd_atomic >=
 424                                     qp->s_max_rd_atomic) {
 425                                         qp->s_flags |= IPATH_S_RDMAR_PENDING;
 426                                         goto bail;
 427                                 }
 428                                 qp->s_num_rd_atomic++;
 429                                 if (qp->s_lsn != (u32) -1)
 430                                         qp->s_lsn++;
 431                                 wqe->lpsn = wqe->psn;
 432                         }
 433                         if (wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP) {
 434                                 qp->s_state = OP(COMPARE_SWAP);
 435                                 ohdr->u.atomic_eth.swap_data = cpu_to_be64(
 436                                         wqe->wr.wr.atomic.swap);
 437                                 ohdr->u.atomic_eth.compare_data = cpu_to_be64(
 438                                         wqe->wr.wr.atomic.compare_add);
 439                         } else {
 440                                 qp->s_state = OP(FETCH_ADD);
 441                                 ohdr->u.atomic_eth.swap_data = cpu_to_be64(
 442                                         wqe->wr.wr.atomic.compare_add);
 443                                 ohdr->u.atomic_eth.compare_data = 0;
 444                         }
 445                         ohdr->u.atomic_eth.vaddr[0] = cpu_to_be32(
 446                                 wqe->wr.wr.atomic.remote_addr >> 32);
 447                         ohdr->u.atomic_eth.vaddr[1] = cpu_to_be32(
 448                                 wqe->wr.wr.atomic.remote_addr);
 449                         ohdr->u.atomic_eth.rkey = cpu_to_be32(
 450                                 wqe->wr.wr.atomic.rkey);
 451                         hwords += sizeof(struct ib_atomic_eth) / sizeof(u32);
 452                         ss = NULL;
 453                         len = 0;
 454                         if (++qp->s_cur == qp->s_size)
 455                                 qp->s_cur = 0;
 456                         break;
 457
 458                 default:
 459                         goto bail;
 460                 }
 461                 qp->s_sge.sge = wqe->sg_list[0];
 462                 qp->s_sge.sg_list = wqe->sg_list + 1;
 463                 qp->s_sge.num_sge = wqe->wr.num_sge;
 464                 qp->s_len = wqe->length;
 465                 if (newreq) {
 466                         qp->s_tail++;
 467                         if (qp->s_tail >= qp->s_size)
 468                                 qp->s_tail = 0;
 469                 }
 470                 bth2 |= qp->s_psn & IPATH_PSN_MASK;
 471                 if (wqe->wr.opcode == IB_WR_RDMA_READ)
 472                         qp->s_psn = wqe->lpsn + 1;
 473                 else {
 474                         qp->s_psn++;
 475                         if (ipath_cmp24(qp->s_psn, qp->s_next_psn) > 0)
 476                                 qp->s_next_psn = qp->s_psn;
 477                 }
 478                 /*
 479                  * Put the QP on the pending list so lost ACKs will cause
 480                  * a retry.  More than one request can be pending so the
 481                  * QP may already be on the dev->pending list.
 482                  */
 483                 spin_lock(&dev->pending_lock);
 484                 if (list_empty(&qp->timerwait))
 485                         list_add_tail(&qp->timerwait,
 486                                       &dev->pending[dev->pending_index]);
 487                 spin_unlock(&dev->pending_lock);
 488                 break;
 489
 490         case OP(RDMA_READ_RESPONSE_FIRST):
 491                 /*
 492                  * This case can only happen if a send is restarted.
 493                  * See ipath_restart_rc().
 494                  */
 495                 ipath_init_restart(qp, wqe);
 496                 /* FALLTHROUGH */
 497         case OP(SEND_FIRST):
 498                 qp->s_state = OP(SEND_MIDDLE);
 499                 /* FALLTHROUGH */
 500         case OP(SEND_MIDDLE):
 501                 bth2 = qp->s_psn++ & IPATH_PSN_MASK;
 502                 if (ipath_cmp24(qp->s_psn, qp->s_next_psn) > 0)
 503                         qp->s_next_psn = qp->s_psn;
 504                 ss = &qp->s_sge;
 505                 len = qp->s_len;
 506                 if (len > pmtu) {
 507                         len = pmtu;
 508                         break;
 509                 }
 510                 if (wqe->wr.opcode == IB_WR_SEND)
 511                         qp->s_state = OP(SEND_LAST);
 512                 else {
 513                         qp->s_state = OP(SEND_LAST_WITH_IMMEDIATE);
 514                         /* Immediate data comes after the BTH */
 515                         ohdr->u.imm_data = wqe->wr.ex.imm_data;
 516                         hwords += 1;
 517                 }
 518                 if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 519                         bth0 |= 1 << 23;
 520                 bth2 |= 1 << 31;        /* Request ACK. */
 521                 qp->s_cur++;
 522                 if (qp->s_cur >= qp->s_size)
 523                         qp->s_cur = 0;
 524                 break;
 525
 526         case OP(RDMA_READ_RESPONSE_LAST):
 527                 /*
 528                  * This case can only happen if a RDMA write is restarted.
 529                  * See ipath_restart_rc().
 530                  */
 531                 ipath_init_restart(qp, wqe);
 532                 /* FALLTHROUGH */
 533         case OP(RDMA_WRITE_FIRST):
 534                 qp->s_state = OP(RDMA_WRITE_MIDDLE);
 535                 /* FALLTHROUGH */
 536         case OP(RDMA_WRITE_MIDDLE):
 537                 bth2 = qp->s_psn++ & IPATH_PSN_MASK;
 538                 if (ipath_cmp24(qp->s_psn, qp->s_next_psn) > 0)
 539                         qp->s_next_psn = qp->s_psn;
 540                 ss = &qp->s_sge;
 541                 len = qp->s_len;
 542                 if (len > pmtu) {
 543                         len = pmtu;
 544                         break;
 545                 }
 546                 if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
 547                         qp->s_state = OP(RDMA_WRITE_LAST);
 548                 else {
 549                         qp->s_state = OP(RDMA_WRITE_LAST_WITH_IMMEDIATE);
 550                         /* Immediate data comes after the BTH */
 551                         ohdr->u.imm_data = wqe->wr.ex.imm_data;
 552                         hwords += 1;
 553                         if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 554                                 bth0 |= 1 << 23;
 555                 }
 556                 bth2 |= 1 << 31;        /* Request ACK. */
 557                 qp->s_cur++;
 558                 if (qp->s_cur >= qp->s_size)
 559                         qp->s_cur = 0;
 560                 break;
 561
 562         case OP(RDMA_READ_RESPONSE_MIDDLE):
 563                 /*
 564                  * This case can only happen if a RDMA read is restarted.
 565                  * See ipath_restart_rc().
 566                  */
 567                 ipath_init_restart(qp, wqe);
 568                 len = ((qp->s_psn - wqe->psn) & IPATH_PSN_MASK) * pmtu;
 569                 ohdr->u.rc.reth.vaddr =
 570                         cpu_to_be64(wqe->wr.wr.rdma.remote_addr + len);
 571                 ohdr->u.rc.reth.rkey =
 572                         cpu_to_be32(wqe->wr.wr.rdma.rkey);
 573                 ohdr->u.rc.reth.length = cpu_to_be32(qp->s_len);
 574                 qp->s_state = OP(RDMA_READ_REQUEST);
 575                 hwords += sizeof(ohdr->u.rc.reth) / sizeof(u32);
 576                 bth2 = qp->s_psn++ & IPATH_PSN_MASK;
 577                 if (ipath_cmp24(qp->s_psn, qp->s_next_psn) > 0)
 578                         qp->s_next_psn = qp->s_psn;
 579                 ss = NULL;
 580                 len = 0;
 581                 qp->s_cur++;
 582                 if (qp->s_cur == qp->s_size)
 583                         qp->s_cur = 0;
 584                 break;
 585         }
 586         if (ipath_cmp24(qp->s_psn, qp->s_last_psn + IPATH_PSN_CREDIT - 1) >= 0)
 587                 bth2 |= 1 << 31;        /* Request ACK. */
 588         qp->s_len -= len;
 589         qp->s_hdrwords = hwords;
 590         qp->s_cur_sge = ss;
 591         qp->s_cur_size = len;
 592         ipath_make_ruc_header(dev, qp, ohdr, bth0 | (qp->s_state << 24), bth2);
 593 done:
 594         ret = 1;
 595         goto unlock;
 596
 597 bail:
 598         qp->s_flags &= ~IPATH_S_BUSY;
 599 unlock:
 600         spin_unlock_irqrestore(&qp->s_lock, flags);
 601         return ret;
 602 }
 603
 604 /**
 605  * send_rc_ack - Construct an ACK packet and send it
 606  * @qp: a pointer to the QP
 607  *
 608  * This is called from ipath_rc_rcv() and only uses the receive
 609  * side QP state.
 610  * Note that RDMA reads and atomics are handled in the
 611  * send side QP state and tasklet.
 612  */
 613 static void send_rc_ack(struct ipath_qp *qp)
 614 {
 615         struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
 616         struct ipath_devdata *dd;
 617         u16 lrh0;
 618         u32 bth0;
 619         u32 hwords;
 620         u32 __iomem *piobuf;
 621         struct ipath_ib_header hdr;
 622         struct ipath_other_headers *ohdr;
 623         unsigned long flags;
 624
 625         spin_lock_irqsave(&qp->s_lock, flags);
 626
 627         /* Don't send ACK or NAK if a RDMA read or atomic is pending. */
 628         if (qp->r_head_ack_queue != qp->s_tail_ack_queue ||
 629             (qp->s_flags & IPATH_S_ACK_PENDING) ||
 630             qp->s_ack_state != OP(ACKNOWLEDGE))
 631                 goto queue_ack;
 632
 633         spin_unlock_irqrestore(&qp->s_lock, flags);
 634
 635         /* Don't try to send ACKs if the link isn't ACTIVE */
 636         dd = dev->dd;
 637         if (!(dd->ipath_flags & IPATH_LINKACTIVE))
 638                 goto done;
 639
 640         piobuf = ipath_getpiobuf(dd, 0, NULL);
 641         if (!piobuf) {
 642                 /*
 643                  * We are out of PIO buffers at the moment.
 644                  * Pass responsibility for sending the ACK to the
 645                  * send tasklet so that when a PIO buffer becomes
 646                  * available, the ACK is sent ahead of other outgoing
 647                  * packets.
 648                  */
 649                 spin_lock_irqsave(&qp->s_lock, flags);
 650                 goto queue_ack;
 651         }
 652
 653         /* Construct the header. */
 654         ohdr = &hdr.u.oth;
 655         lrh0 = IPATH_LRH_BTH;
 656         /* header size in 32-bit words LRH+BTH+AETH = (8+12+4)/4. */
 657         hwords = 6;
 658         if (unlikely(qp->remote_ah_attr.ah_flags & IB_AH_GRH)) {
 659                 hwords += ipath_make_grh(dev, &hdr.u.l.grh,
 660                                          &qp->remote_ah_attr.grh,
 661                                          hwords, 0);
 662                 ohdr = &hdr.u.l.oth;
 663                 lrh0 = IPATH_LRH_GRH;
 664         }
 665         /* read pkey_index w/o lock (its atomic) */
 666         bth0 = ipath_get_pkey(dd, qp->s_pkey_index) |
 667                 (OP(ACKNOWLEDGE) << 24) | (1 << 22);
 668         if (qp->r_nak_state)
 669                 ohdr->u.aeth = cpu_to_be32((qp->r_msn & IPATH_MSN_MASK) |
 670                                             (qp->r_nak_state <<
 671                                              IPATH_AETH_CREDIT_SHIFT));
 672         else
 673                 ohdr->u.aeth = ipath_compute_aeth(qp);
 674         lrh0 |= qp->remote_ah_attr.sl << 4;
 675         hdr.lrh[0] = cpu_to_be16(lrh0);
 676         hdr.lrh[1] = cpu_to_be16(qp->remote_ah_attr.dlid);
 677         hdr.lrh[2] = cpu_to_be16(hwords + SIZE_OF_CRC);
 678         hdr.lrh[3] = cpu_to_be16(dd->ipath_lid);
 679         ohdr->bth[0] = cpu_to_be32(bth0);
 680         ohdr->bth[1] = cpu_to_be32(qp->remote_qpn);
 681         ohdr->bth[2] = cpu_to_be32(qp->r_ack_psn & IPATH_PSN_MASK);
 682
 683         writeq(hwords + 1, piobuf);
 684
 685         if (dd->ipath_flags & IPATH_PIO_FLUSH_WC) {
 686                 u32 *hdrp = (u32 *) &hdr;
 687
 688                 ipath_flush_wc();
 689                 __iowrite32_copy(piobuf + 2, hdrp, hwords - 1);
 690                 ipath_flush_wc();
 691                 __raw_writel(hdrp[hwords - 1], piobuf + hwords + 1);
 692         } else
 693                 __iowrite32_copy(piobuf + 2, (u32 *) &hdr, hwords);
 694
 695         ipath_flush_wc();
 696
 697         dev->n_unicast_xmit++;
 698         goto done;
 699
 700 queue_ack:
 701         if (ib_ipath_state_ops[qp->state] & IPATH_PROCESS_RECV_OK) {
 702                 dev->n_rc_qacks++;
 703                 qp->s_flags |= IPATH_S_ACK_PENDING;
 704                 qp->s_nak_state = qp->r_nak_state;
 705                 qp->s_ack_psn = qp->r_ack_psn;
 706
 707                 /* Schedule the send tasklet. */
 708                 ipath_schedule_send(qp);
 709         }
 710         spin_unlock_irqrestore(&qp->s_lock, flags);
 711 done:
 712         return;
 713 }
 714
 715 /**
 716  * reset_psn - reset the QP state to send starting from PSN
 717  * @qp: the QP
 718  * @psn: the packet sequence number to restart at
 719  *
 720  * This is called from ipath_rc_rcv() to process an incoming RC ACK
 721  * for the given QP.
 722  * Called at interrupt level with the QP s_lock held.
 723  */
 724 static void reset_psn(struct ipath_qp *qp, u32 psn)
 725 {
 726         u32 n = qp->s_last;
 727         struct ipath_swqe *wqe = get_swqe_ptr(qp, n);
 728         u32 opcode;
 729
 730         qp->s_cur = n;
 731
 732         /*
 733          * If we are starting the request from the beginning,
 734          * let the normal send code handle initialization.
 735          */
 736         if (ipath_cmp24(psn, wqe->psn) <= 0) {
 737                 qp->s_state = OP(SEND_LAST);
 738                 goto done;
 739         }
 740
 741         /* Find the work request opcode corresponding to the given PSN. */
 742         opcode = wqe->wr.opcode;
 743         for (;;) {
 744                 int diff;
 745
 746                 if (++n == qp->s_size)
 747                         n = 0;
 748                 if (n == qp->s_tail)
 749                         break;
 750                 wqe = get_swqe_ptr(qp, n);
 751                 diff = ipath_cmp24(psn, wqe->psn);
 752                 if (diff < 0)
 753                         break;
 754                 qp->s_cur = n;
 755                 /*
 756                  * If we are starting the request from the beginning,
 757                  * let the normal send code handle initialization.
 758                  */
 759                 if (diff == 0) {
 760                         qp->s_state = OP(SEND_LAST);
 761                         goto done;
 762                 }
 763                 opcode = wqe->wr.opcode;
 764         }
 765
 766         /*
 767          * Set the state to restart in the middle of a request.
 768          * Don't change the s_sge, s_cur_sge, or s_cur_size.
 769          * See ipath_make_rc_req().
 770          */
 771         switch (opcode) {
 772         case IB_WR_SEND:
 773         case IB_WR_SEND_WITH_IMM:
 774                 qp->s_state = OP(RDMA_READ_RESPONSE_FIRST);
 775                 break;
 776
 777         case IB_WR_RDMA_WRITE:
 778         case IB_WR_RDMA_WRITE_WITH_IMM:
 779                 qp->s_state = OP(RDMA_READ_RESPONSE_LAST);
 780                 break;
 781
 782         case IB_WR_RDMA_READ:
 783                 qp->s_state = 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 done:
 794         qp->s_psn = psn;
 795 }
 796
 797 /**
 798  * ipath_restart_rc - back up requester to resend the last un-ACKed request
 799  * @qp: the QP to restart
 800  * @psn: packet sequence number for the request
 801  * @wc: the work completion request
 802  *
 803  * The QP s_lock should be held and interrupts disabled.
 804  */
 805 void ipath_restart_rc(struct ipath_qp *qp, u32 psn)
 806 {
 807         struct ipath_swqe *wqe = get_swqe_ptr(qp, qp->s_last);
 808         struct ipath_ibdev *dev;
 809
 810         if (qp->s_retry == 0) {
 811                 ipath_send_complete(qp, wqe, IB_WC_RETRY_EXC_ERR);
 812                 ipath_error_qp(qp, IB_WC_WR_FLUSH_ERR);
 813                 goto bail;
 814         }
 815         qp->s_retry--;
 816
 817         /*
 818          * Remove the QP from the timeout queue.
 819          * Note: it may already have been removed by ipath_ib_timer().
 820          */
 821         dev = to_idev(qp->ibqp.device);
 822         spin_lock(&dev->pending_lock);
 823         if (!list_empty(&qp->timerwait))
 824                 list_del_init(&qp->timerwait);
 825         if (!list_empty(&qp->piowait))
 826                 list_del_init(&qp->piowait);
 827         spin_unlock(&dev->pending_lock);
 828
 829         if (wqe->wr.opcode == IB_WR_RDMA_READ)
 830                 dev->n_rc_resends++;
 831         else
 832                 dev->n_rc_resends += (qp->s_psn - psn) & IPATH_PSN_MASK;
 833
 834         reset_psn(qp, psn);
 835         ipath_schedule_send(qp);
 836
 837 bail:
 838         return;
 839 }
 840
 841 static inline void update_last_psn(struct ipath_qp *qp, u32 psn)
 842 {
 843         qp->s_last_psn = psn;
 844 }
 845
 846 /**
 847  * do_rc_ack - process an incoming RC ACK
 848  * @qp: the QP the ACK came in on
 849  * @psn: the packet sequence number of the ACK
 850  * @opcode: the opcode of the request that resulted in the ACK
 851  *
 852  * This is called from ipath_rc_rcv_resp() to process an incoming RC ACK
 853  * for the given QP.
 854  * Called at interrupt level with the QP s_lock held and interrupts disabled.
 855  * Returns 1 if OK, 0 if current operation should be aborted (NAK).
 856  */
 857 static int do_rc_ack(struct ipath_qp *qp, u32 aeth, u32 psn, int opcode,
 858                      u64 val)
 859 {
 860         struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
 861         struct ib_wc wc;
 862         enum ib_wc_status status;
 863         struct ipath_swqe *wqe;
 864         int ret = 0;
 865         u32 ack_psn;
 866         int diff;
 867
 868         /*
 869          * Remove the QP from the timeout queue (or RNR timeout queue).
 870          * If ipath_ib_timer() has already removed it,
 871          * it's OK since we hold the QP s_lock and ipath_restart_rc()
 872          * just won't find anything to restart if we ACK everything.
 873          */
 874         spin_lock(&dev->pending_lock);
 875         if (!list_empty(&qp->timerwait))
 876                 list_del_init(&qp->timerwait);
 877         spin_unlock(&dev->pending_lock);
 878
 879         /*
 880          * Note that NAKs implicitly ACK outstanding SEND and RDMA write
 881          * requests and implicitly NAK RDMA read and atomic requests issued
 882          * before the NAK'ed request.  The MSN won't include the NAK'ed
 883          * request but will include an ACK'ed request(s).
 884          */
 885         ack_psn = psn;
 886         if (aeth >> 29)
 887                 ack_psn--;
 888         wqe = get_swqe_ptr(qp, qp->s_last);
 889
 890         /*
 891          * The MSN might be for a later WQE than the PSN indicates so
 892          * only complete WQEs that the PSN finishes.
 893          */
 894         while ((diff = ipath_cmp24(ack_psn, wqe->lpsn)) >= 0) {
 895                 /*
 896                  * RDMA_READ_RESPONSE_ONLY is a special case since
 897                  * we want to generate completion events for everything
 898                  * before the RDMA read, copy the data, then generate
 899                  * the completion for the read.
 900                  */
 901                 if (wqe->wr.opcode == IB_WR_RDMA_READ &&
 902                     opcode == OP(RDMA_READ_RESPONSE_ONLY) &&
 903                     diff == 0) {
 904                         ret = 1;
 905                         goto bail;
 906                 }
 907                 /*
 908                  * If this request is a RDMA read or atomic, and the ACK is
 909                  * for a later operation, this ACK NAKs the RDMA read or
 910                  * atomic.  In other words, only a RDMA_READ_LAST or ONLY
 911                  * can ACK a RDMA read and likewise for atomic ops.  Note
 912                  * that the NAK case can only happen if relaxed ordering is
 913                  * used and requests are sent after an RDMA read or atomic
 914                  * is sent but before the response is received.
 915                  */
 916                 if ((wqe->wr.opcode == IB_WR_RDMA_READ &&
 917                      (opcode != OP(RDMA_READ_RESPONSE_LAST) || diff != 0)) ||
 918                     ((wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
 919                       wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) &&
 920                      (opcode != OP(ATOMIC_ACKNOWLEDGE) || diff != 0))) {
 921                         /*
 922                          * The last valid PSN seen is the previous
 923                          * request's.
 924                          */
 925                         update_last_psn(qp, wqe->psn - 1);
 926                         /* Retry this request. */
 927                         ipath_restart_rc(qp, wqe->psn);
 928                         /*
 929                          * No need to process the ACK/NAK since we are
 930                          * restarting an earlier request.
 931                          */
 932                         goto bail;
 933                 }
 934                 if (wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
 935                     wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)
 936                         *(u64 *) wqe->sg_list[0].vaddr = val;
 937                 if (qp->s_num_rd_atomic &&
 938                     (wqe->wr.opcode == IB_WR_RDMA_READ ||
 939                      wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
 940                      wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)) {
 941                         qp->s_num_rd_atomic--;
 942                         /* Restart sending task if fence is complete */
 943                         if (((qp->s_flags & IPATH_S_FENCE_PENDING) &&
 944                              !qp->s_num_rd_atomic) ||
 945                             qp->s_flags & IPATH_S_RDMAR_PENDING)
 946                                 ipath_schedule_send(qp);
 947                 }
 948                 /* Post a send completion queue entry if requested. */
 949                 if (!(qp->s_flags & IPATH_S_SIGNAL_REQ_WR) ||
 950                     (wqe->wr.send_flags & IB_SEND_SIGNALED)) {
 951                         memset(&wc, 0, sizeof wc);
 952                         wc.wr_id = wqe->wr.wr_id;
 953                         wc.status = IB_WC_SUCCESS;
 954                         wc.opcode = ib_ipath_wc_opcode[wqe->wr.opcode];
 955                         wc.byte_len = wqe->length;
 956                         wc.qp = &qp->ibqp;
 957                         wc.src_qp = qp->remote_qpn;
 958                         wc.slid = qp->remote_ah_attr.dlid;
 959                         wc.sl = qp->remote_ah_attr.sl;
 960                         ipath_cq_enter(to_icq(qp->ibqp.send_cq), &wc, 0);
 961                 }
 962                 qp->s_retry = qp->s_retry_cnt;
 963                 /*
 964                  * If we are completing a request which is in the process of
 965                  * being resent, we can stop resending it since we know the
 966                  * responder has already seen it.
 967                  */
 968                 if (qp->s_last == qp->s_cur) {
 969                         if (++qp->s_cur >= qp->s_size)
 970                                 qp->s_cur = 0;
 971                         qp->s_last = qp->s_cur;
 972                         if (qp->s_last == qp->s_tail)
 973                                 break;
 974                         wqe = get_swqe_ptr(qp, qp->s_cur);
 975                         qp->s_state = OP(SEND_LAST);
 976                         qp->s_psn = wqe->psn;
 977                 } else {
 978                         if (++qp->s_last >= qp->s_size)
 979                                 qp->s_last = 0;
 980                         if (qp->state == IB_QPS_SQD && qp->s_last == qp->s_cur)
 981                                 qp->s_draining = 0;
 982                         if (qp->s_last == qp->s_tail)
 983                                 break;
 984                         wqe = get_swqe_ptr(qp, qp->s_last);
 985                 }
 986         }
 987
 988         switch (aeth >> 29) {
 989         case 0:         /* ACK */
 990                 dev->n_rc_acks++;
 991                 /* If this is a partial ACK, reset the retransmit timer. */
 992                 if (qp->s_last != qp->s_tail) {
 993                         spin_lock(&dev->pending_lock);
 994                         if (list_empty(&qp->timerwait))
 995                                 list_add_tail(&qp->timerwait,
 996                                         &dev->pending[dev->pending_index]);
 997                         spin_unlock(&dev->pending_lock);
 998                         /*
 999                          * If we get a partial ACK for a resent operation,
1000                          * we can stop resending the earlier packets and
1001                          * continue with the next packet the receiver wants.
1002                          */
1003                         if (ipath_cmp24(qp->s_psn, psn) <= 0) {
1004                                 reset_psn(qp, psn + 1);
1005                                 ipath_schedule_send(qp);
1006                         }
1007                 } else if (ipath_cmp24(qp->s_psn, psn) <= 0) {
1008                         qp->s_state = OP(SEND_LAST);
1009                         qp->s_psn = psn + 1;
1010                 }
1011                 ipath_get_credit(qp, aeth);
1012                 qp->s_rnr_retry = qp->s_rnr_retry_cnt;
1013                 qp->s_retry = qp->s_retry_cnt;
1014                 update_last_psn(qp, psn);
1015                 ret = 1;
1016                 goto bail;
1017
1018         case 1:         /* RNR NAK */
1019                 dev->n_rnr_naks++;
1020                 if (qp->s_last == qp->s_tail)
1021                         goto bail;
1022                 if (qp->s_rnr_retry == 0) {
1023                         status = IB_WC_RNR_RETRY_EXC_ERR;
1024                         goto class_b;
1025                 }
1026                 if (qp->s_rnr_retry_cnt < 7)
1027                         qp->s_rnr_retry--;
1028
1029                 /* The last valid PSN is the previous PSN. */
1030                 update_last_psn(qp, psn - 1);
1031
1032                 if (wqe->wr.opcode == IB_WR_RDMA_READ)
1033                         dev->n_rc_resends++;
1034                 else
1035                         dev->n_rc_resends +=
1036                                 (qp->s_psn - psn) & IPATH_PSN_MASK;
1037
1038                 reset_psn(qp, psn);
1039
1040                 qp->s_rnr_timeout =
1041                         ib_ipath_rnr_table[(aeth >> IPATH_AETH_CREDIT_SHIFT) &
1042                                            IPATH_AETH_CREDIT_MASK];
1043                 ipath_insert_rnr_queue(qp);
1044                 ipath_schedule_send(qp);
1045                 goto bail;
1046
1047         case 3:         /* NAK */
1048                 if (qp->s_last == qp->s_tail)
1049                         goto bail;
1050                 /* The last valid PSN is the previous PSN. */
1051                 update_last_psn(qp, psn - 1);
1052                 switch ((aeth >> IPATH_AETH_CREDIT_SHIFT) &
1053                         IPATH_AETH_CREDIT_MASK) {
1054                 case 0: /* PSN sequence error */
1055                         dev->n_seq_naks++;
1056                         /*
1057                          * Back up to the responder's expected PSN.
1058                          * Note that we might get a NAK in the middle of an
1059                          * RDMA READ response which terminates the RDMA
1060                          * READ.
1061                          */
1062                         ipath_restart_rc(qp, psn);
1063                         break;
1064
1065                 case 1: /* Invalid Request */
1066                         status = IB_WC_REM_INV_REQ_ERR;
1067                         dev->n_other_naks++;
1068                         goto class_b;
1069
1070                 case 2: /* Remote Access Error */
1071                         status = IB_WC_REM_ACCESS_ERR;
1072                         dev->n_other_naks++;
1073                         goto class_b;
1074
1075                 case 3: /* Remote Operation Error */
1076                         status = IB_WC_REM_OP_ERR;
1077                         dev->n_other_naks++;
1078                 class_b:
1079                         ipath_send_complete(qp, wqe, status);
1080                         ipath_error_qp(qp, IB_WC_WR_FLUSH_ERR);
1081                         break;
1082
1083                 default:
1084                         /* Ignore other reserved NAK error codes */
1085                         goto reserved;
1086                 }
1087                 qp->s_rnr_retry = qp->s_rnr_retry_cnt;
1088                 goto bail;
1089
1090         default:                /* 2: reserved */
1091         reserved:
1092                 /* Ignore reserved NAK codes. */
1093                 goto bail;
1094         }
1095
1096 bail:
1097         return ret;
1098 }
1099
1100 /**
1101  * ipath_rc_rcv_resp - process an incoming RC response packet
1102  * @dev: the device this packet came in on
1103  * @ohdr: the other headers for this packet
1104  * @data: the packet data
1105  * @tlen: the packet length
1106  * @qp: the QP for this packet
1107  * @opcode: the opcode for this packet
1108  * @psn: the packet sequence number for this packet
1109  * @hdrsize: the header length
1110  * @pmtu: the path MTU
1111  * @header_in_data: true if part of the header data is in the data buffer
1112  *
1113  * This is called from ipath_rc_rcv() to process an incoming RC response
1114  * packet for the given QP.
1115  * Called at interrupt level.
1116  */
1117 static inline void ipath_rc_rcv_resp(struct ipath_ibdev *dev,
1118                                      struct ipath_other_headers *ohdr,
1119                                      void *data, u32 tlen,
1120                                      struct ipath_qp *qp,
1121                                      u32 opcode,
1122                                      u32 psn, u32 hdrsize, u32 pmtu,
1123                                      int header_in_data)
1124 {
1125         struct ipath_swqe *wqe;
1126         enum ib_wc_status status;
1127         unsigned long flags;
1128         int diff;
1129         u32 pad;
1130         u32 aeth;
1131         u64 val;
1132
1133         spin_lock_irqsave(&qp->s_lock, flags);
1134
1135         /* Double check we can process this now that we hold the s_lock. */
1136         if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_RECV_OK))
1137                 goto ack_done;
1138
1139         /* Ignore invalid responses. */
1140         if (ipath_cmp24(psn, qp->s_next_psn) >= 0)
1141                 goto ack_done;
1142
1143         /* Ignore duplicate responses. */
1144         diff = ipath_cmp24(psn, qp->s_last_psn);
1145         if (unlikely(diff <= 0)) {
1146                 /* Update credits for "ghost" ACKs */
1147                 if (diff == 0 && opcode == OP(ACKNOWLEDGE)) {
1148                         if (!header_in_data)
1149                                 aeth = be32_to_cpu(ohdr->u.aeth);
1150                         else {
1151                                 aeth = be32_to_cpu(((__be32 *) data)[0]);
1152                                 data += sizeof(__be32);
1153                         }
1154                         if ((aeth >> 29) == 0)
1155                                 ipath_get_credit(qp, aeth);
1156                 }
1157                 goto ack_done;
1158         }
1159
1160         if (unlikely(qp->s_last == qp->s_tail))
1161                 goto ack_done;
1162         wqe = get_swqe_ptr(qp, qp->s_last);
1163         status = IB_WC_SUCCESS;
1164
1165         switch (opcode) {
1166         case OP(ACKNOWLEDGE):
1167         case OP(ATOMIC_ACKNOWLEDGE):
1168         case OP(RDMA_READ_RESPONSE_FIRST):
1169                 if (!header_in_data)
1170                         aeth = be32_to_cpu(ohdr->u.aeth);
1171                 else {
1172                         aeth = be32_to_cpu(((__be32 *) data)[0]);
1173                         data += sizeof(__be32);
1174                 }
1175                 if (opcode == OP(ATOMIC_ACKNOWLEDGE)) {
1176                         if (!header_in_data) {
1177                                 __be32 *p = ohdr->u.at.atomic_ack_eth;
1178
1179                                 val = ((u64) be32_to_cpu(p[0]) << 32) |
1180                                         be32_to_cpu(p[1]);
1181                         } else
1182                                 val = be64_to_cpu(((__be64 *) data)[0]);
1183                 } else
1184                         val = 0;
1185                 if (!do_rc_ack(qp, aeth, psn, opcode, val) ||
1186                     opcode != OP(RDMA_READ_RESPONSE_FIRST))
1187                         goto ack_done;
1188                 hdrsize += 4;
1189                 wqe = get_swqe_ptr(qp, qp->s_last);
1190                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1191                         goto ack_op_err;
1192                 qp->r_flags &= ~IPATH_R_RDMAR_SEQ;
1193                 /*
1194                  * If this is a response to a resent RDMA read, we
1195                  * have to be careful to copy the data to the right
1196                  * location.
1197                  */
1198                 qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
1199                                                   wqe, psn, pmtu);
1200                 goto read_middle;
1201
1202         case OP(RDMA_READ_RESPONSE_MIDDLE):
1203                 /* no AETH, no ACK */
1204                 if (unlikely(ipath_cmp24(psn, qp->s_last_psn + 1))) {
1205                         dev->n_rdma_seq++;
1206                         if (qp->r_flags & IPATH_R_RDMAR_SEQ)
1207                                 goto ack_done;
1208                         qp->r_flags |= IPATH_R_RDMAR_SEQ;
1209                         ipath_restart_rc(qp, qp->s_last_psn + 1);
1210                         goto ack_done;
1211                 }
1212                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1213                         goto ack_op_err;
1214         read_middle:
1215                 if (unlikely(tlen != (hdrsize + pmtu + 4)))
1216                         goto ack_len_err;
1217                 if (unlikely(pmtu >= qp->s_rdma_read_len))
1218                         goto ack_len_err;
1219
1220                 /* We got a response so update the timeout. */
1221                 spin_lock(&dev->pending_lock);
1222                 if (qp->s_rnr_timeout == 0 && !list_empty(&qp->timerwait))
1223                         list_move_tail(&qp->timerwait,
1224                                        &dev->pending[dev->pending_index]);
1225                 spin_unlock(&dev->pending_lock);
1226
1227                 if (opcode == OP(RDMA_READ_RESPONSE_MIDDLE))
1228                         qp->s_retry = qp->s_retry_cnt;
1229
1230                 /*
1231                  * Update the RDMA receive state but do the copy w/o
1232                  * holding the locks and blocking interrupts.
1233                  */
1234                 qp->s_rdma_read_len -= pmtu;
1235                 update_last_psn(qp, psn);
1236                 spin_unlock_irqrestore(&qp->s_lock, flags);
1237                 ipath_copy_sge(&qp->s_rdma_read_sge, data, pmtu);
1238                 goto bail;
1239
1240         case OP(RDMA_READ_RESPONSE_ONLY):
1241                 if (!header_in_data)
1242                         aeth = be32_to_cpu(ohdr->u.aeth);
1243                 else
1244                         aeth = be32_to_cpu(((__be32 *) data)[0]);
1245                 if (!do_rc_ack(qp, aeth, psn, opcode, 0))
1246                         goto ack_done;
1247                 /* Get the number of bytes the message was padded by. */
1248                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1249                 /*
1250                  * Check that the data size is >= 0 && <= pmtu.
1251                  * Remember to account for the AETH header (4) and
1252                  * ICRC (4).
1253                  */
1254                 if (unlikely(tlen < (hdrsize + pad + 8)))
1255                         goto ack_len_err;
1256                 /*
1257                  * If this is a response to a resent RDMA read, we
1258                  * have to be careful to copy the data to the right
1259                  * location.
1260                  */
1261                 wqe = get_swqe_ptr(qp, qp->s_last);
1262                 qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
1263                                                   wqe, psn, pmtu);
1264                 goto read_last;
1265
1266         case OP(RDMA_READ_RESPONSE_LAST):
1267                 /* ACKs READ req. */
1268                 if (unlikely(ipath_cmp24(psn, qp->s_last_psn + 1))) {
1269                         dev->n_rdma_seq++;
1270                         if (qp->r_flags & IPATH_R_RDMAR_SEQ)
1271                                 goto ack_done;
1272                         qp->r_flags |= IPATH_R_RDMAR_SEQ;
1273                         ipath_restart_rc(qp, qp->s_last_psn + 1);
1274                         goto ack_done;
1275                 }
1276                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1277                         goto ack_op_err;
1278                 /* Get the number of bytes the message was padded by. */
1279                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1280                 /*
1281                  * Check that the data size is >= 1 && <= pmtu.
1282                  * Remember to account for the AETH header (4) and
1283                  * ICRC (4).
1284                  */
1285                 if (unlikely(tlen <= (hdrsize + pad + 8)))
1286                         goto ack_len_err;
1287         read_last:
1288                 tlen -= hdrsize + pad + 8;
1289                 if (unlikely(tlen != qp->s_rdma_read_len))
1290                         goto ack_len_err;
1291                 if (!header_in_data)
1292                         aeth = be32_to_cpu(ohdr->u.aeth);
1293                 else {
1294                         aeth = be32_to_cpu(((__be32 *) data)[0]);
1295                         data += sizeof(__be32);
1296                 }
1297                 ipath_copy_sge(&qp->s_rdma_read_sge, data, tlen);
1298                 (void) do_rc_ack(qp, aeth, psn,
1299                                  OP(RDMA_READ_RESPONSE_LAST), 0);
1300                 goto ack_done;
1301         }
1302
1303 ack_op_err:
1304         status = IB_WC_LOC_QP_OP_ERR;
1305         goto ack_err;
1306
1307 ack_len_err:
1308         status = IB_WC_LOC_LEN_ERR;
1309 ack_err:
1310         ipath_send_complete(qp, wqe, status);
1311         ipath_error_qp(qp, IB_WC_WR_FLUSH_ERR);
1312 ack_done:
1313         spin_unlock_irqrestore(&qp->s_lock, flags);
1314 bail:
1315         return;
1316 }
1317
1318 /**
1319  * ipath_rc_rcv_error - process an incoming duplicate or error RC packet
1320  * @dev: the device this packet came in on
1321  * @ohdr: the other headers for this packet
1322  * @data: the packet data
1323  * @qp: the QP for this packet
1324  * @opcode: the opcode for this packet
1325  * @psn: the packet sequence number for this packet
1326  * @diff: the difference between the PSN and the expected PSN
1327  * @header_in_data: true if part of the header data is in the data buffer
1328  *
1329  * This is called from ipath_rc_rcv() to process an unexpected
1330  * incoming RC packet for the given QP.
1331  * Called at interrupt level.
1332  * Return 1 if no more processing is needed; otherwise return 0 to
1333  * schedule a response to be sent.
1334  */
1335 static inline int ipath_rc_rcv_error(struct ipath_ibdev *dev,
1336                                      struct ipath_other_headers *ohdr,
1337                                      void *data,
1338                                      struct ipath_qp *qp,
1339                                      u32 opcode,
1340                                      u32 psn,
1341                                      int diff,
1342                                      int header_in_data)
1343 {
1344         struct ipath_ack_entry *e;
1345         u8 i, prev;
1346         int old_req;
1347         unsigned long flags;
1348
1349         if (diff > 0) {
1350                 /*
1351                  * Packet sequence error.
1352                  * A NAK will ACK earlier sends and RDMA writes.
1353                  * Don't queue the NAK if we already sent one.
1354                  */
1355                 if (!qp->r_nak_state) {
1356                         qp->r_nak_state = IB_NAK_PSN_ERROR;
1357                         /* Use the expected PSN. */
1358                         qp->r_ack_psn = qp->r_psn;
1359                         goto send_ack;
1360                 }
1361                 goto done;
1362         }
1363
1364         /*
1365          * Handle a duplicate request.  Don't re-execute SEND, RDMA
1366          * write or atomic op.  Don't NAK errors, just silently drop
1367          * the duplicate request.  Note that r_sge, r_len, and
1368          * r_rcv_len may be in use so don't modify them.
1369          *
1370          * We are supposed to ACK the earliest duplicate PSN but we
1371          * can coalesce an outstanding duplicate ACK.  We have to
1372          * send the earliest so that RDMA reads can be restarted at
1373          * the requester's expected PSN.
1374          *
1375          * First, find where this duplicate PSN falls within the
1376          * ACKs previously sent.
1377          */
1378         psn &= IPATH_PSN_MASK;
1379         e = NULL;
1380         old_req = 1;
1381
1382         spin_lock_irqsave(&qp->s_lock, flags);
1383         /* Double check we can process this now that we hold the s_lock. */
1384         if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_RECV_OK))
1385                 goto unlock_done;
1386
1387         for (i = qp->r_head_ack_queue; ; i = prev) {
1388                 if (i == qp->s_tail_ack_queue)
1389                         old_req = 0;
1390                 if (i)
1391                         prev = i - 1;
1392                 else
1393                         prev = IPATH_MAX_RDMA_ATOMIC;
1394                 if (prev == qp->r_head_ack_queue) {
1395                         e = NULL;
1396                         break;
1397                 }
1398                 e = &qp->s_ack_queue[prev];
1399                 if (!e->opcode) {
1400                         e = NULL;
1401                         break;
1402                 }
1403                 if (ipath_cmp24(psn, e->psn) >= 0) {
1404                         if (prev == qp->s_tail_ack_queue)
1405                                 old_req = 0;
1406                         break;
1407                 }
1408         }
1409         switch (opcode) {
1410         case OP(RDMA_READ_REQUEST): {
1411                 struct ib_reth *reth;
1412                 u32 offset;
1413                 u32 len;
1414
1415                 /*
1416                  * If we didn't find the RDMA read request in the ack queue,
1417                  * or the send tasklet is already backed up to send an
1418                  * earlier entry, we can ignore this request.
1419                  */
1420                 if (!e || e->opcode != OP(RDMA_READ_REQUEST) || old_req)
1421                         goto unlock_done;
1422                 /* RETH comes after BTH */
1423                 if (!header_in_data)
1424                         reth = &ohdr->u.rc.reth;
1425                 else {
1426                         reth = (struct ib_reth *)data;
1427                         data += sizeof(*reth);
1428                 }
1429                 /*
1430                  * Address range must be a subset of the original
1431                  * request and start on pmtu boundaries.
1432                  * We reuse the old ack_queue slot since the requester
1433                  * should not back up and request an earlier PSN for the
1434                  * same request.
1435                  */
1436                 offset = ((psn - e->psn) & IPATH_PSN_MASK) *
1437                         ib_mtu_enum_to_int(qp->path_mtu);
1438                 len = be32_to_cpu(reth->length);
1439                 if (unlikely(offset + len > e->rdma_sge.sge.sge_length))
1440                         goto unlock_done;
1441                 if (len != 0) {
1442                         u32 rkey = be32_to_cpu(reth->rkey);
1443                         u64 vaddr = be64_to_cpu(reth->vaddr);
1444                         int ok;
1445
1446                         ok = ipath_rkey_ok(qp, &e->rdma_sge,
1447                                            len, vaddr, rkey,
1448                                            IB_ACCESS_REMOTE_READ);
1449                         if (unlikely(!ok))
1450                                 goto unlock_done;
1451                 } else {
1452                         e->rdma_sge.sg_list = NULL;
1453                         e->rdma_sge.num_sge = 0;
1454                         e->rdma_sge.sge.mr = NULL;
1455                         e->rdma_sge.sge.vaddr = NULL;
1456                         e->rdma_sge.sge.length = 0;
1457                         e->rdma_sge.sge.sge_length = 0;
1458                 }
1459                 e->psn = psn;
1460                 qp->s_ack_state = OP(ACKNOWLEDGE);
1461                 qp->s_tail_ack_queue = prev;
1462                 break;
1463         }
1464
1465         case OP(COMPARE_SWAP):
1466         case OP(FETCH_ADD): {
1467                 /*
1468                  * If we didn't find the atomic request in the ack queue
1469                  * or the send tasklet is already backed up to send an
1470                  * earlier entry, we can ignore this request.
1471                  */
1472                 if (!e || e->opcode != (u8) opcode || old_req)
1473                         goto unlock_done;
1474                 qp->s_ack_state = OP(ACKNOWLEDGE);
1475                 qp->s_tail_ack_queue = prev;
1476                 break;
1477         }
1478
1479         default:
1480                 if (old_req)
1481                         goto unlock_done;
1482                 /*
1483                  * Resend the most recent ACK if this request is
1484                  * after all the previous RDMA reads and atomics.
1485                  */
1486                 if (i == qp->r_head_ack_queue) {
1487                         spin_unlock_irqrestore(&qp->s_lock, flags);
1488                         qp->r_nak_state = 0;
1489                         qp->r_ack_psn = qp->r_psn - 1;
1490                         goto send_ack;
1491                 }
1492                 /*
1493                  * Try to send a simple ACK to work around a Mellanox bug
1494                  * which doesn't accept a RDMA read response or atomic
1495                  * response as an ACK for earlier SENDs or RDMA writes.
1496                  */
1497                 if (qp->r_head_ack_queue == qp->s_tail_ack_queue &&
1498                     !(qp->s_flags & IPATH_S_ACK_PENDING) &&
1499                     qp->s_ack_state == OP(ACKNOWLEDGE)) {
1500                         spin_unlock_irqrestore(&qp->s_lock, flags);
1501                         qp->r_nak_state = 0;
1502                         qp->r_ack_psn = qp->s_ack_queue[i].psn - 1;
1503                         goto send_ack;
1504                 }
1505                 /*
1506                  * Resend the RDMA read or atomic op which
1507                  * ACKs this duplicate request.
1508                  */
1509                 qp->s_ack_state = OP(ACKNOWLEDGE);
1510                 qp->s_tail_ack_queue = i;
1511                 break;
1512         }
1513         qp->r_nak_state = 0;
1514         ipath_schedule_send(qp);
1515
1516 unlock_done:
1517         spin_unlock_irqrestore(&qp->s_lock, flags);
1518 done:
1519         return 1;
1520
1521 send_ack:
1522         return 0;
1523 }
1524
1525 void ipath_rc_error(struct ipath_qp *qp, enum ib_wc_status err)
1526 {
1527         unsigned long flags;
1528         int lastwqe;
1529
1530         spin_lock_irqsave(&qp->s_lock, flags);
1531         lastwqe = ipath_error_qp(qp, err);
1532         spin_unlock_irqrestore(&qp->s_lock, flags);
1533
1534         if (lastwqe) {
1535                 struct ib_event ev;
1536
1537                 ev.device = qp->ibqp.device;
1538                 ev.element.qp = &qp->ibqp;
1539                 ev.event = IB_EVENT_QP_LAST_WQE_REACHED;
1540                 qp->ibqp.event_handler(&ev, qp->ibqp.qp_context);
1541         }
1542 }
1543
1544 static inline void ipath_update_ack_queue(struct ipath_qp *qp, unsigned n)
1545 {
1546         unsigned next;
1547
1548         next = n + 1;
1549         if (next > IPATH_MAX_RDMA_ATOMIC)
1550                 next = 0;
1551         if (n == qp->s_tail_ack_queue) {
1552                 qp->s_tail_ack_queue = next;
1553                 qp->s_ack_state = OP(ACKNOWLEDGE);
1554         }
1555 }
1556
1557 /**
1558  * ipath_rc_rcv - process an incoming RC packet
1559  * @dev: the device this packet came in on
1560  * @hdr: the header of this packet
1561  * @has_grh: true if the header has a GRH
1562  * @data: the packet data
1563  * @tlen: the packet length
1564  * @qp: the QP for this packet
1565  *
1566  * This is called from ipath_qp_rcv() to process an incoming RC packet
1567  * for the given QP.
1568  * Called at interrupt level.
1569  */
1570 void ipath_rc_rcv(struct ipath_ibdev *dev, struct ipath_ib_header *hdr,
1571                   int has_grh, void *data, u32 tlen, struct ipath_qp *qp)
1572 {
1573         struct ipath_other_headers *ohdr;
1574         u32 opcode;
1575         u32 hdrsize;
1576         u32 psn;
1577         u32 pad;
1578         struct ib_wc wc;
1579         u32 pmtu = ib_mtu_enum_to_int(qp->path_mtu);
1580         int diff;
1581         struct ib_reth *reth;
1582         int header_in_data;
1583         unsigned long flags;
1584
1585         /* Validate the SLID. See Ch. 9.6.1.5 */
1586         if (unlikely(be16_to_cpu(hdr->lrh[3]) != qp->remote_ah_attr.dlid))
1587                 goto done;
1588
1589         /* Check for GRH */
1590         if (!has_grh) {
1591                 ohdr = &hdr->u.oth;
1592                 hdrsize = 8 + 12;       /* LRH + BTH */
1593                 psn = be32_to_cpu(ohdr->bth[2]);
1594                 header_in_data = 0;
1595         } else {
1596                 ohdr = &hdr->u.l.oth;
1597                 hdrsize = 8 + 40 + 12;  /* LRH + GRH + BTH */
1598                 /*
1599                  * The header with GRH is 60 bytes and the core driver sets
1600                  * the eager header buffer size to 56 bytes so the last 4
1601                  * bytes of the BTH header (PSN) is in the data buffer.
1602                  */
1603                 header_in_data = dev->dd->ipath_rcvhdrentsize == 16;
1604                 if (header_in_data) {
1605                         psn = be32_to_cpu(((__be32 *) data)[0]);
1606                         data += sizeof(__be32);
1607                 } else
1608                         psn = be32_to_cpu(ohdr->bth[2]);
1609         }
1610
1611         /*
1612          * Process responses (ACKs) before anything else.  Note that the
1613          * packet sequence number will be for something in the send work
1614          * queue rather than the expected receive packet sequence number.
1615          * In other words, this QP is the requester.
1616          */
1617         opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
1618         if (opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
1619             opcode <= OP(ATOMIC_ACKNOWLEDGE)) {
1620                 ipath_rc_rcv_resp(dev, ohdr, data, tlen, qp, opcode, psn,
1621                                   hdrsize, pmtu, header_in_data);
1622                 goto done;
1623         }
1624
1625         /* Compute 24 bits worth of difference. */
1626         diff = ipath_cmp24(psn, qp->r_psn);
1627         if (unlikely(diff)) {
1628                 if (ipath_rc_rcv_error(dev, ohdr, data, qp, opcode,
1629                                        psn, diff, header_in_data))
1630                         goto done;
1631                 goto send_ack;
1632         }
1633
1634         /* Check for opcode sequence errors. */
1635         switch (qp->r_state) {
1636         case OP(SEND_FIRST):
1637         case OP(SEND_MIDDLE):
1638                 if (opcode == OP(SEND_MIDDLE) ||
1639                     opcode == OP(SEND_LAST) ||
1640                     opcode == OP(SEND_LAST_WITH_IMMEDIATE))
1641                         break;
1642                 goto nack_inv;
1643
1644         case OP(RDMA_WRITE_FIRST):
1645         case OP(RDMA_WRITE_MIDDLE):
1646                 if (opcode == OP(RDMA_WRITE_MIDDLE) ||
1647                     opcode == OP(RDMA_WRITE_LAST) ||
1648                     opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
1649                         break;
1650                 goto nack_inv;
1651
1652         default:
1653                 if (opcode == OP(SEND_MIDDLE) ||
1654                     opcode == OP(SEND_LAST) ||
1655                     opcode == OP(SEND_LAST_WITH_IMMEDIATE) ||
1656                     opcode == OP(RDMA_WRITE_MIDDLE) ||
1657                     opcode == OP(RDMA_WRITE_LAST) ||
1658                     opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
1659                         goto nack_inv;
1660                 /*
1661                  * Note that it is up to the requester to not send a new
1662                  * RDMA read or atomic operation before receiving an ACK
1663                  * for the previous operation.
1664                  */
1665                 break;
1666         }
1667
1668         memset(&wc, 0, sizeof wc);
1669
1670         /* OK, process the packet. */
1671         switch (opcode) {
1672         case OP(SEND_FIRST):
1673                 if (!ipath_get_rwqe(qp, 0))
1674                         goto rnr_nak;
1675                 qp->r_rcv_len = 0;
1676                 /* FALLTHROUGH */
1677         case OP(SEND_MIDDLE):
1678         case OP(RDMA_WRITE_MIDDLE):
1679         send_middle:
1680                 /* Check for invalid length PMTU or posted rwqe len. */
1681                 if (unlikely(tlen != (hdrsize + pmtu + 4)))
1682                         goto nack_inv;
1683                 qp->r_rcv_len += pmtu;
1684                 if (unlikely(qp->r_rcv_len > qp->r_len))
1685                         goto nack_inv;
1686                 ipath_copy_sge(&qp->r_sge, data, pmtu);
1687                 break;
1688
1689         case OP(RDMA_WRITE_LAST_WITH_IMMEDIATE):
1690                 /* consume RWQE */
1691                 if (!ipath_get_rwqe(qp, 1))
1692                         goto rnr_nak;
1693                 goto send_last_imm;
1694
1695         case OP(SEND_ONLY):
1696         case OP(SEND_ONLY_WITH_IMMEDIATE):
1697                 if (!ipath_get_rwqe(qp, 0))
1698                         goto rnr_nak;
1699                 qp->r_rcv_len = 0;
1700                 if (opcode == OP(SEND_ONLY))
1701                         goto send_last;
1702                 /* FALLTHROUGH */
1703         case OP(SEND_LAST_WITH_IMMEDIATE):
1704         send_last_imm:
1705                 if (header_in_data) {
1706                         wc.ex.imm_data = *(__be32 *) data;
1707                         data += sizeof(__be32);
1708                 } else {
1709                         /* Immediate data comes after BTH */
1710                         wc.ex.imm_data = ohdr->u.imm_data;
1711                 }
1712                 hdrsize += 4;
1713                 wc.wc_flags = IB_WC_WITH_IMM;
1714                 /* FALLTHROUGH */
1715         case OP(SEND_LAST):
1716         case OP(RDMA_WRITE_LAST):
1717         send_last:
1718                 /* Get the number of bytes the message was padded by. */
1719                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1720                 /* Check for invalid length. */
1721                 /* XXX LAST len should be >= 1 */
1722                 if (unlikely(tlen < (hdrsize + pad + 4)))
1723                         goto nack_inv;
1724                 /* Don't count the CRC. */
1725                 tlen -= (hdrsize + pad + 4);
1726                 wc.byte_len = tlen + qp->r_rcv_len;
1727                 if (unlikely(wc.byte_len > qp->r_len))
1728                         goto nack_inv;
1729                 ipath_copy_sge(&qp->r_sge, data, tlen);
1730                 qp->r_msn++;
1731                 if (!test_and_clear_bit(IPATH_R_WRID_VALID, &qp->r_aflags))
1732                         break;
1733                 wc.wr_id = qp->r_wr_id;
1734                 wc.status = IB_WC_SUCCESS;
1735                 if (opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE) ||
1736                     opcode == OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE))
1737                         wc.opcode = IB_WC_RECV_RDMA_WITH_IMM;
1738                 else
1739                         wc.opcode = IB_WC_RECV;
1740                 wc.qp = &qp->ibqp;
1741                 wc.src_qp = qp->remote_qpn;
1742                 wc.slid = qp->remote_ah_attr.dlid;
1743                 wc.sl = qp->remote_ah_attr.sl;
1744                 /* Signal completion event if the solicited bit is set. */
1745                 ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
1746                                (ohdr->bth[0] &
1747                                 __constant_cpu_to_be32(1 << 23)) != 0);
1748                 break;
1749
1750         case OP(RDMA_WRITE_FIRST):
1751         case OP(RDMA_WRITE_ONLY):
1752         case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE):
1753                 if (unlikely(!(qp->qp_access_flags &
1754                                IB_ACCESS_REMOTE_WRITE)))
1755                         goto nack_inv;
1756                 /* consume RWQE */
1757                 /* RETH comes after BTH */
1758                 if (!header_in_data)
1759                         reth = &ohdr->u.rc.reth;
1760                 else {
1761                         reth = (struct ib_reth *)data;
1762                         data += sizeof(*reth);
1763                 }
1764                 hdrsize += sizeof(*reth);
1765                 qp->r_len = be32_to_cpu(reth->length);
1766                 qp->r_rcv_len = 0;
1767                 if (qp->r_len != 0) {
1768                         u32 rkey = be32_to_cpu(reth->rkey);
1769                         u64 vaddr = be64_to_cpu(reth->vaddr);
1770                         int ok;
1771
1772                         /* Check rkey & NAK */
1773                         ok = ipath_rkey_ok(qp, &qp->r_sge,
1774                                            qp->r_len, vaddr, rkey,
1775                                            IB_ACCESS_REMOTE_WRITE);
1776                         if (unlikely(!ok))
1777                                 goto nack_acc;
1778                 } else {
1779                         qp->r_sge.sg_list = NULL;
1780                         qp->r_sge.sge.mr = NULL;
1781                         qp->r_sge.sge.vaddr = NULL;
1782                         qp->r_sge.sge.length = 0;
1783                         qp->r_sge.sge.sge_length = 0;
1784                 }
1785                 if (opcode == OP(RDMA_WRITE_FIRST))
1786                         goto send_middle;
1787                 else if (opcode == OP(RDMA_WRITE_ONLY))
1788                         goto send_last;
1789                 if (!ipath_get_rwqe(qp, 1))
1790                         goto rnr_nak;
1791                 goto send_last_imm;
1792
1793         case OP(RDMA_READ_REQUEST): {
1794                 struct ipath_ack_entry *e;
1795                 u32 len;
1796                 u8 next;
1797
1798                 if (unlikely(!(qp->qp_access_flags &
1799                                IB_ACCESS_REMOTE_READ)))
1800                         goto nack_inv;
1801                 next = qp->r_head_ack_queue + 1;
1802                 if (next > IPATH_MAX_RDMA_ATOMIC)
1803                         next = 0;
1804                 spin_lock_irqsave(&qp->s_lock, flags);
1805                 /* Double check we can process this while holding the s_lock. */
1806                 if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_RECV_OK))
1807                         goto unlock;
1808                 if (unlikely(next == qp->s_tail_ack_queue)) {
1809                         if (!qp->s_ack_queue[next].sent)
1810                                 goto nack_inv_unlck;
1811                         ipath_update_ack_queue(qp, next);
1812                 }
1813                 e = &qp->s_ack_queue[qp->r_head_ack_queue];
1814                 /* RETH comes after BTH */
1815                 if (!header_in_data)
1816                         reth = &ohdr->u.rc.reth;
1817                 else {
1818                         reth = (struct ib_reth *)data;
1819                         data += sizeof(*reth);
1820                 }
1821                 len = be32_to_cpu(reth->length);
1822                 if (len) {
1823                         u32 rkey = be32_to_cpu(reth->rkey);
1824                         u64 vaddr = be64_to_cpu(reth->vaddr);
1825                         int ok;
1826
1827                         /* Check rkey & NAK */
1828                         ok = ipath_rkey_ok(qp, &e->rdma_sge, len, vaddr,
1829                                            rkey, IB_ACCESS_REMOTE_READ);
1830                         if (unlikely(!ok))
1831                                 goto nack_acc_unlck;
1832                         /*
1833                          * Update the next expected PSN.  We add 1 later
1834                          * below, so only add the remainder here.
1835                          */
1836                         if (len > pmtu)
1837                                 qp->r_psn += (len - 1) / pmtu;
1838                 } else {
1839                         e->rdma_sge.sg_list = NULL;
1840                         e->rdma_sge.num_sge = 0;
1841                         e->rdma_sge.sge.mr = NULL;
1842                         e->rdma_sge.sge.vaddr = NULL;
1843                         e->rdma_sge.sge.length = 0;
1844                         e->rdma_sge.sge.sge_length = 0;
1845                 }
1846                 e->opcode = opcode;
1847                 e->sent = 0;
1848                 e->psn = psn;
1849                 /*
1850                  * We need to increment the MSN here instead of when we
1851                  * finish sending the result since a duplicate request would
1852                  * increment it more than once.
1853                  */
1854                 qp->r_msn++;
1855                 qp->r_psn++;
1856                 qp->r_state = opcode;
1857                 qp->r_nak_state = 0;
1858                 qp->r_head_ack_queue = next;
1859
1860                 /* Schedule the send tasklet. */
1861                 ipath_schedule_send(qp);
1862
1863                 goto unlock;
1864         }
1865
1866         case OP(COMPARE_SWAP):
1867         case OP(FETCH_ADD): {
1868                 struct ib_atomic_eth *ateth;
1869                 struct ipath_ack_entry *e;
1870                 u64 vaddr;
1871                 atomic64_t *maddr;
1872                 u64 sdata;
1873                 u32 rkey;
1874                 u8 next;
1875
1876                 if (unlikely(!(qp->qp_access_flags &
1877                                IB_ACCESS_REMOTE_ATOMIC)))
1878                         goto nack_inv;
1879                 next = qp->r_head_ack_queue + 1;
1880                 if (next > IPATH_MAX_RDMA_ATOMIC)
1881                         next = 0;
1882                 spin_lock_irqsave(&qp->s_lock, flags);
1883                 /* Double check we can process this while holding the s_lock. */
1884                 if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_RECV_OK))
1885                         goto unlock;
1886                 if (unlikely(next == qp->s_tail_ack_queue)) {
1887                         if (!qp->s_ack_queue[next].sent)
1888                                 goto nack_inv_unlck;
1889                         ipath_update_ack_queue(qp, next);
1890                 }
1891                 if (!header_in_data)
1892                         ateth = &ohdr->u.atomic_eth;
1893                 else
1894                         ateth = (struct ib_atomic_eth *)data;
1895                 vaddr = ((u64) be32_to_cpu(ateth->vaddr[0]) << 32) |
1896                         be32_to_cpu(ateth->vaddr[1]);
1897                 if (unlikely(vaddr & (sizeof(u64) - 1)))
1898                         goto nack_inv_unlck;
1899                 rkey = be32_to_cpu(ateth->rkey);
1900                 /* Check rkey & NAK */
1901                 if (unlikely(!ipath_rkey_ok(qp, &qp->r_sge,
1902                                             sizeof(u64), vaddr, rkey,
1903                                             IB_ACCESS_REMOTE_ATOMIC)))
1904                         goto nack_acc_unlck;
1905                 /* Perform atomic OP and save result. */
1906                 maddr = (atomic64_t *) qp->r_sge.sge.vaddr;
1907                 sdata = be64_to_cpu(ateth->swap_data);
1908                 e = &qp->s_ack_queue[qp->r_head_ack_queue];
1909                 e->atomic_data = (opcode == OP(FETCH_ADD)) ?
1910                         (u64) atomic64_add_return(sdata, maddr) - sdata :
1911                         (u64) cmpxchg((u64 *) qp->r_sge.sge.vaddr,
1912                                       be64_to_cpu(ateth->compare_data),
1913                                       sdata);
1914                 e->opcode = opcode;
1915                 e->sent = 0;
1916                 e->psn = psn & IPATH_PSN_MASK;
1917                 qp->r_msn++;
1918                 qp->r_psn++;
1919                 qp->r_state = opcode;
1920                 qp->r_nak_state = 0;
1921                 qp->r_head_ack_queue = next;
1922
1923                 /* Schedule the send tasklet. */
1924                 ipath_schedule_send(qp);
1925
1926                 goto unlock;
1927         }
1928
1929         default:
1930                 /* NAK unknown opcodes. */
1931                 goto nack_inv;
1932         }
1933         qp->r_psn++;
1934         qp->r_state = opcode;
1935         qp->r_ack_psn = psn;
1936         qp->r_nak_state = 0;
1937         /* Send an ACK if requested or required. */
1938         if (psn & (1 << 31))
1939                 goto send_ack;
1940         goto done;
1941
1942 rnr_nak:
1943         qp->r_nak_state = IB_RNR_NAK | qp->r_min_rnr_timer;
1944         qp->r_ack_psn = qp->r_psn;
1945         goto send_ack;
1946
1947 nack_inv_unlck:
1948         spin_unlock_irqrestore(&qp->s_lock, flags);
1949 nack_inv:
1950         ipath_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
1951         qp->r_nak_state = IB_NAK_INVALID_REQUEST;
1952         qp->r_ack_psn = qp->r_psn;
1953         goto send_ack;
1954
1955 nack_acc_unlck:
1956         spin_unlock_irqrestore(&qp->s_lock, flags);
1957 nack_acc:
1958         ipath_rc_error(qp, IB_WC_LOC_PROT_ERR);
1959         qp->r_nak_state = IB_NAK_REMOTE_ACCESS_ERROR;
1960         qp->r_ack_psn = qp->r_psn;
1961 send_ack:
1962         send_rc_ack(qp);
1963         goto done;
1964
1965 unlock:
1966         spin_unlock_irqrestore(&qp->s_lock, flags);
1967 done:
1968         return;
1969 }