drivers/infiniband/hw/qib/qib_rc.c

   1 /*
   2  * Copyright (c) 2006, 2007, 2008, 2009 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 "qib.h"
  37
  38 /* cut down ridiculously long IB macro names */
  39 #define OP(x) IB_OPCODE_RC_##x
  40
  41 static void rc_timeout(unsigned long arg);
  42
  43 static u32 restart_sge(struct qib_sge_state *ss, struct qib_swqe *wqe,
  44                        u32 psn, u32 pmtu)
  45 {
  46         u32 len;
  47
  48         len = ((psn - wqe->psn) & QIB_PSN_MASK) * pmtu;
  49         ss->sge = wqe->sg_list[0];
  50         ss->sg_list = wqe->sg_list + 1;
  51         ss->num_sge = wqe->wr.num_sge;
  52         ss->total_len = wqe->length;
  53         qib_skip_sge(ss, len, 0);
  54         return wqe->length - len;
  55 }
  56
  57 static void start_timer(struct qib_qp *qp)
  58 {
  59         qp->s_flags |= QIB_S_TIMER;
  60         qp->s_timer.function = rc_timeout;
  61         /* 4.096 usec. * (1 << qp->timeout) */
  62         qp->s_timer.expires = jiffies +
  63                 usecs_to_jiffies((4096UL * (1UL << qp->timeout)) / 1000UL);
  64         add_timer(&qp->s_timer);
  65 }
  66
  67 /**
  68  * qib_make_rc_ack - construct a response packet (ACK, NAK, or RDMA read)
  69  * @dev: the device for this QP
  70  * @qp: a pointer to the QP
  71  * @ohdr: a pointer to the IB header being constructed
  72  * @pmtu: the path MTU
  73  *
  74  * Return 1 if constructed; otherwise, return 0.
  75  * Note that we are in the responder's side of the QP context.
  76  * Note the QP s_lock must be held.
  77  */
  78 static int qib_make_rc_ack(struct qib_ibdev *dev, struct qib_qp *qp,
  79                            struct qib_other_headers *ohdr, u32 pmtu)
  80 {
  81         struct qib_ack_entry *e;
  82         u32 hwords;
  83         u32 len;
  84         u32 bth0;
  85         u32 bth2;
  86
  87         /* Don't send an ACK if we aren't supposed to. */
  88         if (!(ib_qib_state_ops[qp->state] & QIB_PROCESS_RECV_OK))
  89                 goto bail;
  90
  91         /* header size in 32-bit words LRH+BTH = (8+12)/4. */
  92         hwords = 5;
  93
  94         switch (qp->s_ack_state) {
  95         case OP(RDMA_READ_RESPONSE_LAST):
  96         case OP(RDMA_READ_RESPONSE_ONLY):
  97                 e = &qp->s_ack_queue[qp->s_tail_ack_queue];
  98                 if (e->rdma_sge.mr) {
  99                         atomic_dec(&e->rdma_sge.mr->refcount);
 100                         e->rdma_sge.mr = NULL;
 101                 }
 102                 /* FALLTHROUGH */
 103         case OP(ATOMIC_ACKNOWLEDGE):
 104                 /*
 105                  * We can increment the tail pointer now that the last
 106                  * response has been sent instead of only being
 107                  * constructed.
 108                  */
 109                 if (++qp->s_tail_ack_queue > QIB_MAX_RDMA_ATOMIC)
 110                         qp->s_tail_ack_queue = 0;
 111                 /* FALLTHROUGH */
 112         case OP(SEND_ONLY):
 113         case OP(ACKNOWLEDGE):
 114                 /* Check for no next entry in the queue. */
 115                 if (qp->r_head_ack_queue == qp->s_tail_ack_queue) {
 116                         if (qp->s_flags & QIB_S_ACK_PENDING)
 117                                 goto normal;
 118                         goto bail;
 119                 }
 120
 121                 e = &qp->s_ack_queue[qp->s_tail_ack_queue];
 122                 if (e->opcode == OP(RDMA_READ_REQUEST)) {
 123                         /*
 124                          * If a RDMA read response is being resent and
 125                          * we haven't seen the duplicate request yet,
 126                          * then stop sending the remaining responses the
 127                          * responder has seen until the requester resends it.
 128                          */
 129                         len = e->rdma_sge.sge_length;
 130                         if (len && !e->rdma_sge.mr) {
 131                                 qp->s_tail_ack_queue = qp->r_head_ack_queue;
 132                                 goto bail;
 133                         }
 134                         /* Copy SGE state in case we need to resend */
 135                         qp->s_rdma_mr = e->rdma_sge.mr;
 136                         if (qp->s_rdma_mr)
 137                                 atomic_inc(&qp->s_rdma_mr->refcount);
 138                         qp->s_ack_rdma_sge.sge = e->rdma_sge;
 139                         qp->s_ack_rdma_sge.num_sge = 1;
 140                         qp->s_cur_sge = &qp->s_ack_rdma_sge;
 141                         if (len > pmtu) {
 142                                 len = pmtu;
 143                                 qp->s_ack_state = OP(RDMA_READ_RESPONSE_FIRST);
 144                         } else {
 145                                 qp->s_ack_state = OP(RDMA_READ_RESPONSE_ONLY);
 146                                 e->sent = 1;
 147                         }
 148                         ohdr->u.aeth = qib_compute_aeth(qp);
 149                         hwords++;
 150                         qp->s_ack_rdma_psn = e->psn;
 151                         bth2 = qp->s_ack_rdma_psn++ & QIB_PSN_MASK;
 152                 } else {
 153                         /* COMPARE_SWAP or FETCH_ADD */
 154                         qp->s_cur_sge = NULL;
 155                         len = 0;
 156                         qp->s_ack_state = OP(ATOMIC_ACKNOWLEDGE);
 157                         ohdr->u.at.aeth = qib_compute_aeth(qp);
 158                         ohdr->u.at.atomic_ack_eth[0] =
 159                                 cpu_to_be32(e->atomic_data >> 32);
 160                         ohdr->u.at.atomic_ack_eth[1] =
 161                                 cpu_to_be32(e->atomic_data);
 162                         hwords += sizeof(ohdr->u.at) / sizeof(u32);
 163                         bth2 = e->psn & QIB_PSN_MASK;
 164                         e->sent = 1;
 165                 }
 166                 bth0 = qp->s_ack_state << 24;
 167                 break;
 168
 169         case OP(RDMA_READ_RESPONSE_FIRST):
 170                 qp->s_ack_state = OP(RDMA_READ_RESPONSE_MIDDLE);
 171                 /* FALLTHROUGH */
 172         case OP(RDMA_READ_RESPONSE_MIDDLE):
 173                 qp->s_cur_sge = &qp->s_ack_rdma_sge;
 174                 qp->s_rdma_mr = qp->s_ack_rdma_sge.sge.mr;
 175                 if (qp->s_rdma_mr)
 176                         atomic_inc(&qp->s_rdma_mr->refcount);
 177                 len = qp->s_ack_rdma_sge.sge.sge_length;
 178                 if (len > pmtu)
 179                         len = pmtu;
 180                 else {
 181                         ohdr->u.aeth = qib_compute_aeth(qp);
 182                         hwords++;
 183                         qp->s_ack_state = OP(RDMA_READ_RESPONSE_LAST);
 184                         e = &qp->s_ack_queue[qp->s_tail_ack_queue];
 185                         e->sent = 1;
 186                 }
 187                 bth0 = qp->s_ack_state << 24;
 188                 bth2 = qp->s_ack_rdma_psn++ & QIB_PSN_MASK;
 189                 break;
 190
 191         default:
 192 normal:
 193                 /*
 194                  * Send a regular ACK.
 195                  * Set the s_ack_state so we wait until after sending
 196                  * the ACK before setting s_ack_state to ACKNOWLEDGE
 197                  * (see above).
 198                  */
 199                 qp->s_ack_state = OP(SEND_ONLY);
 200                 qp->s_flags &= ~QIB_S_ACK_PENDING;
 201                 qp->s_cur_sge = NULL;
 202                 if (qp->s_nak_state)
 203                         ohdr->u.aeth =
 204                                 cpu_to_be32((qp->r_msn & QIB_MSN_MASK) |
 205                                             (qp->s_nak_state <<
 206                                              QIB_AETH_CREDIT_SHIFT));
 207                 else
 208                         ohdr->u.aeth = qib_compute_aeth(qp);
 209                 hwords++;
 210                 len = 0;
 211                 bth0 = OP(ACKNOWLEDGE) << 24;
 212                 bth2 = qp->s_ack_psn & QIB_PSN_MASK;
 213         }
 214         qp->s_rdma_ack_cnt++;
 215         qp->s_hdrwords = hwords;
 216         qp->s_cur_size = len;
 217         qib_make_ruc_header(qp, ohdr, bth0, bth2);
 218         return 1;
 219
 220 bail:
 221         qp->s_ack_state = OP(ACKNOWLEDGE);
 222         qp->s_flags &= ~(QIB_S_RESP_PENDING | QIB_S_ACK_PENDING);
 223         return 0;
 224 }
 225
 226 /**
 227  * qib_make_rc_req - construct a request packet (SEND, RDMA r/w, ATOMIC)
 228  * @qp: a pointer to the QP
 229  *
 230  * Return 1 if constructed; otherwise, return 0.
 231  */
 232 int qib_make_rc_req(struct qib_qp *qp)
 233 {
 234         struct qib_ibdev *dev = to_idev(qp->ibqp.device);
 235         struct qib_other_headers *ohdr;
 236         struct qib_sge_state *ss;
 237         struct qib_swqe *wqe;
 238         u32 hwords;
 239         u32 len;
 240         u32 bth0;
 241         u32 bth2;
 242         u32 pmtu = ib_mtu_enum_to_int(qp->path_mtu);
 243         char newreq;
 244         unsigned long flags;
 245         int ret = 0;
 246         int delta;
 247
 248         ohdr = &qp->s_hdr.u.oth;
 249         if (qp->remote_ah_attr.ah_flags & IB_AH_GRH)
 250                 ohdr = &qp->s_hdr.u.l.oth;
 251
 252         /*
 253          * The lock is needed to synchronize between the sending tasklet,
 254          * the receive interrupt handler, and timeout resends.
 255          */
 256         spin_lock_irqsave(&qp->s_lock, flags);
 257
 258         /* Sending responses has higher priority over sending requests. */
 259         if ((qp->s_flags & QIB_S_RESP_PENDING) &&
 260             qib_make_rc_ack(dev, qp, ohdr, pmtu))
 261                 goto done;
 262
 263         if (!(ib_qib_state_ops[qp->state] & QIB_PROCESS_SEND_OK)) {
 264                 if (!(ib_qib_state_ops[qp->state] & QIB_FLUSH_SEND))
 265                         goto bail;
 266                 /* We are in the error state, flush the work request. */
 267                 if (qp->s_last == qp->s_head)
 268                         goto bail;
 269                 /* If DMAs are in progress, we can't flush immediately. */
 270                 if (atomic_read(&qp->s_dma_busy)) {
 271                         qp->s_flags |= QIB_S_WAIT_DMA;
 272                         goto bail;
 273                 }
 274                 wqe = get_swqe_ptr(qp, qp->s_last);
 275                 while (qp->s_last != qp->s_acked) {
 276                         qib_send_complete(qp, wqe, IB_WC_SUCCESS);
 277                         if (++qp->s_last >= qp->s_size)
 278                                 qp->s_last = 0;
 279                         wqe = get_swqe_ptr(qp, qp->s_last);
 280                 }
 281                 qib_send_complete(qp, wqe, IB_WC_WR_FLUSH_ERR);
 282                 goto done;
 283         }
 284
 285         if (qp->s_flags & (QIB_S_WAIT_RNR | QIB_S_WAIT_ACK))
 286                 goto bail;
 287
 288         if (qib_cmp24(qp->s_psn, qp->s_sending_hpsn) <= 0) {
 289                 if (qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) <= 0) {
 290                         qp->s_flags |= QIB_S_WAIT_PSN;
 291                         goto bail;
 292                 }
 293                 qp->s_sending_psn = qp->s_psn;
 294                 qp->s_sending_hpsn = qp->s_psn - 1;
 295         }
 296
 297         /* header size in 32-bit words LRH+BTH = (8+12)/4. */
 298         hwords = 5;
 299         bth0 = 0;
 300
 301         /* Send a request. */
 302         wqe = get_swqe_ptr(qp, qp->s_cur);
 303         switch (qp->s_state) {
 304         default:
 305                 if (!(ib_qib_state_ops[qp->state] & QIB_PROCESS_NEXT_SEND_OK))
 306                         goto bail;
 307                 /*
 308                  * Resend an old request or start a new one.
 309                  *
 310                  * We keep track of the current SWQE so that
 311                  * we don't reset the "furthest progress" state
 312                  * if we need to back up.
 313                  */
 314                 newreq = 0;
 315                 if (qp->s_cur == qp->s_tail) {
 316                         /* Check if send work queue is empty. */
 317                         if (qp->s_tail == qp->s_head)
 318                                 goto bail;
 319                         /*
 320                          * If a fence is requested, wait for previous
 321                          * RDMA read and atomic operations to finish.
 322                          */
 323                         if ((wqe->wr.send_flags & IB_SEND_FENCE) &&
 324                             qp->s_num_rd_atomic) {
 325                                 qp->s_flags |= QIB_S_WAIT_FENCE;
 326                                 goto bail;
 327                         }
 328                         wqe->psn = qp->s_next_psn;
 329                         newreq = 1;
 330                 }
 331                 /*
 332                  * Note that we have to be careful not to modify the
 333                  * original work request since we may need to resend
 334                  * it.
 335                  */
 336                 len = wqe->length;
 337                 ss = &qp->s_sge;
 338                 bth2 = qp->s_psn & QIB_PSN_MASK;
 339                 switch (wqe->wr.opcode) {
 340                 case IB_WR_SEND:
 341                 case IB_WR_SEND_WITH_IMM:
 342                         /* If no credit, return. */
 343                         if (!(qp->s_flags & QIB_S_UNLIMITED_CREDIT) &&
 344                             qib_cmp24(wqe->ssn, qp->s_lsn + 1) > 0) {
 345                                 qp->s_flags |= QIB_S_WAIT_SSN_CREDIT;
 346                                 goto bail;
 347                         }
 348                         wqe->lpsn = wqe->psn;
 349                         if (len > pmtu) {
 350                                 wqe->lpsn += (len - 1) / pmtu;
 351                                 qp->s_state = OP(SEND_FIRST);
 352                                 len = pmtu;
 353                                 break;
 354                         }
 355                         if (wqe->wr.opcode == IB_WR_SEND)
 356                                 qp->s_state = OP(SEND_ONLY);
 357                         else {
 358                                 qp->s_state = OP(SEND_ONLY_WITH_IMMEDIATE);
 359                                 /* Immediate data comes after the BTH */
 360                                 ohdr->u.imm_data = wqe->wr.ex.imm_data;
 361                                 hwords += 1;
 362                         }
 363                         if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 364                                 bth0 |= IB_BTH_SOLICITED;
 365                         bth2 |= IB_BTH_REQ_ACK;
 366                         if (++qp->s_cur == qp->s_size)
 367                                 qp->s_cur = 0;
 368                         break;
 369
 370                 case IB_WR_RDMA_WRITE:
 371                         if (newreq && !(qp->s_flags & QIB_S_UNLIMITED_CREDIT))
 372                                 qp->s_lsn++;
 373                         /* FALLTHROUGH */
 374                 case IB_WR_RDMA_WRITE_WITH_IMM:
 375                         /* If no credit, return. */
 376                         if (!(qp->s_flags & QIB_S_UNLIMITED_CREDIT) &&
 377                             qib_cmp24(wqe->ssn, qp->s_lsn + 1) > 0) {
 378                                 qp->s_flags |= QIB_S_WAIT_SSN_CREDIT;
 379                                 goto bail;
 380                         }
 381                         ohdr->u.rc.reth.vaddr =
 382                                 cpu_to_be64(wqe->wr.wr.rdma.remote_addr);
 383                         ohdr->u.rc.reth.rkey =
 384                                 cpu_to_be32(wqe->wr.wr.rdma.rkey);
 385                         ohdr->u.rc.reth.length = cpu_to_be32(len);
 386                         hwords += sizeof(struct ib_reth) / sizeof(u32);
 387                         wqe->lpsn = wqe->psn;
 388                         if (len > pmtu) {
 389                                 wqe->lpsn += (len - 1) / pmtu;
 390                                 qp->s_state = OP(RDMA_WRITE_FIRST);
 391                                 len = pmtu;
 392                                 break;
 393                         }
 394                         if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
 395                                 qp->s_state = OP(RDMA_WRITE_ONLY);
 396                         else {
 397                                 qp->s_state =
 398                                         OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE);
 399                                 /* Immediate data comes after RETH */
 400                                 ohdr->u.rc.imm_data = wqe->wr.ex.imm_data;
 401                                 hwords += 1;
 402                                 if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 403                                         bth0 |= IB_BTH_SOLICITED;
 404                         }
 405                         bth2 |= IB_BTH_REQ_ACK;
 406                         if (++qp->s_cur == qp->s_size)
 407                                 qp->s_cur = 0;
 408                         break;
 409
 410                 case IB_WR_RDMA_READ:
 411                         /*
 412                          * Don't allow more operations to be started
 413                          * than the QP limits allow.
 414                          */
 415                         if (newreq) {
 416                                 if (qp->s_num_rd_atomic >=
 417                                     qp->s_max_rd_atomic) {
 418                                         qp->s_flags |= QIB_S_WAIT_RDMAR;
 419                                         goto bail;
 420                                 }
 421                                 qp->s_num_rd_atomic++;
 422                                 if (!(qp->s_flags & QIB_S_UNLIMITED_CREDIT))
 423                                         qp->s_lsn++;
 424                                 /*
 425                                  * Adjust s_next_psn to count the
 426                                  * expected number of responses.
 427                                  */
 428                                 if (len > pmtu)
 429                                         qp->s_next_psn += (len - 1) / pmtu;
 430                                 wqe->lpsn = qp->s_next_psn++;
 431                         }
 432                         ohdr->u.rc.reth.vaddr =
 433                                 cpu_to_be64(wqe->wr.wr.rdma.remote_addr);
 434                         ohdr->u.rc.reth.rkey =
 435                                 cpu_to_be32(wqe->wr.wr.rdma.rkey);
 436                         ohdr->u.rc.reth.length = cpu_to_be32(len);
 437                         qp->s_state = OP(RDMA_READ_REQUEST);
 438                         hwords += sizeof(ohdr->u.rc.reth) / sizeof(u32);
 439                         ss = NULL;
 440                         len = 0;
 441                         bth2 |= IB_BTH_REQ_ACK;
 442                         if (++qp->s_cur == qp->s_size)
 443                                 qp->s_cur = 0;
 444                         break;
 445
 446                 case IB_WR_ATOMIC_CMP_AND_SWP:
 447                 case IB_WR_ATOMIC_FETCH_AND_ADD:
 448                         /*
 449                          * Don't allow more operations to be started
 450                          * than the QP limits allow.
 451                          */
 452                         if (newreq) {
 453                                 if (qp->s_num_rd_atomic >=
 454                                     qp->s_max_rd_atomic) {
 455                                         qp->s_flags |= QIB_S_WAIT_RDMAR;
 456                                         goto bail;
 457                                 }
 458                                 qp->s_num_rd_atomic++;
 459                                 if (!(qp->s_flags & QIB_S_UNLIMITED_CREDIT))
 460                                         qp->s_lsn++;
 461                                 wqe->lpsn = wqe->psn;
 462                         }
 463                         if (wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP) {
 464                                 qp->s_state = OP(COMPARE_SWAP);
 465                                 ohdr->u.atomic_eth.swap_data = cpu_to_be64(
 466                                         wqe->wr.wr.atomic.swap);
 467                                 ohdr->u.atomic_eth.compare_data = cpu_to_be64(
 468                                         wqe->wr.wr.atomic.compare_add);
 469                         } else {
 470                                 qp->s_state = OP(FETCH_ADD);
 471                                 ohdr->u.atomic_eth.swap_data = cpu_to_be64(
 472                                         wqe->wr.wr.atomic.compare_add);
 473                                 ohdr->u.atomic_eth.compare_data = 0;
 474                         }
 475                         ohdr->u.atomic_eth.vaddr[0] = cpu_to_be32(
 476                                 wqe->wr.wr.atomic.remote_addr >> 32);
 477                         ohdr->u.atomic_eth.vaddr[1] = cpu_to_be32(
 478                                 wqe->wr.wr.atomic.remote_addr);
 479                         ohdr->u.atomic_eth.rkey = cpu_to_be32(
 480                                 wqe->wr.wr.atomic.rkey);
 481                         hwords += sizeof(struct ib_atomic_eth) / sizeof(u32);
 482                         ss = NULL;
 483                         len = 0;
 484                         bth2 |= IB_BTH_REQ_ACK;
 485                         if (++qp->s_cur == qp->s_size)
 486                                 qp->s_cur = 0;
 487                         break;
 488
 489                 default:
 490                         goto bail;
 491                 }
 492                 qp->s_sge.sge = wqe->sg_list[0];
 493                 qp->s_sge.sg_list = wqe->sg_list + 1;
 494                 qp->s_sge.num_sge = wqe->wr.num_sge;
 495                 qp->s_sge.total_len = wqe->length;
 496                 qp->s_len = wqe->length;
 497                 if (newreq) {
 498                         qp->s_tail++;
 499                         if (qp->s_tail >= qp->s_size)
 500                                 qp->s_tail = 0;
 501                 }
 502                 if (wqe->wr.opcode == IB_WR_RDMA_READ)
 503                         qp->s_psn = wqe->lpsn + 1;
 504                 else {
 505                         qp->s_psn++;
 506                         if (qib_cmp24(qp->s_psn, qp->s_next_psn) > 0)
 507                                 qp->s_next_psn = qp->s_psn;
 508                 }
 509                 break;
 510
 511         case OP(RDMA_READ_RESPONSE_FIRST):
 512                 /*
 513                  * qp->s_state is normally set to the opcode of the
 514                  * last packet constructed for new requests and therefore
 515                  * is never set to RDMA read response.
 516                  * RDMA_READ_RESPONSE_FIRST is used by the ACK processing
 517                  * thread to indicate a SEND needs to be restarted from an
 518                  * earlier PSN without interferring with the sending thread.
 519                  * See qib_restart_rc().
 520                  */
 521                 qp->s_len = restart_sge(&qp->s_sge, wqe, qp->s_psn, pmtu);
 522                 /* FALLTHROUGH */
 523         case OP(SEND_FIRST):
 524                 qp->s_state = OP(SEND_MIDDLE);
 525                 /* FALLTHROUGH */
 526         case OP(SEND_MIDDLE):
 527                 bth2 = qp->s_psn++ & QIB_PSN_MASK;
 528                 if (qib_cmp24(qp->s_psn, qp->s_next_psn) > 0)
 529                         qp->s_next_psn = qp->s_psn;
 530                 ss = &qp->s_sge;
 531                 len = qp->s_len;
 532                 if (len > pmtu) {
 533                         len = pmtu;
 534                         break;
 535                 }
 536                 if (wqe->wr.opcode == IB_WR_SEND)
 537                         qp->s_state = OP(SEND_LAST);
 538                 else {
 539                         qp->s_state = OP(SEND_LAST_WITH_IMMEDIATE);
 540                         /* Immediate data comes after the BTH */
 541                         ohdr->u.imm_data = wqe->wr.ex.imm_data;
 542                         hwords += 1;
 543                 }
 544                 if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 545                         bth0 |= IB_BTH_SOLICITED;
 546                 bth2 |= IB_BTH_REQ_ACK;
 547                 qp->s_cur++;
 548                 if (qp->s_cur >= qp->s_size)
 549                         qp->s_cur = 0;
 550                 break;
 551
 552         case OP(RDMA_READ_RESPONSE_LAST):
 553                 /*
 554                  * qp->s_state is normally set to the opcode of the
 555                  * last packet constructed for new requests and therefore
 556                  * is never set to RDMA read response.
 557                  * RDMA_READ_RESPONSE_LAST is used by the ACK processing
 558                  * thread to indicate a RDMA write needs to be restarted from
 559                  * an earlier PSN without interferring with the sending thread.
 560                  * See qib_restart_rc().
 561                  */
 562                 qp->s_len = restart_sge(&qp->s_sge, wqe, qp->s_psn, pmtu);
 563                 /* FALLTHROUGH */
 564         case OP(RDMA_WRITE_FIRST):
 565                 qp->s_state = OP(RDMA_WRITE_MIDDLE);
 566                 /* FALLTHROUGH */
 567         case OP(RDMA_WRITE_MIDDLE):
 568                 bth2 = qp->s_psn++ & QIB_PSN_MASK;
 569                 if (qib_cmp24(qp->s_psn, qp->s_next_psn) > 0)
 570                         qp->s_next_psn = qp->s_psn;
 571                 ss = &qp->s_sge;
 572                 len = qp->s_len;
 573                 if (len > pmtu) {
 574                         len = pmtu;
 575                         break;
 576                 }
 577                 if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
 578                         qp->s_state = OP(RDMA_WRITE_LAST);
 579                 else {
 580                         qp->s_state = OP(RDMA_WRITE_LAST_WITH_IMMEDIATE);
 581                         /* Immediate data comes after the BTH */
 582                         ohdr->u.imm_data = wqe->wr.ex.imm_data;
 583                         hwords += 1;
 584                         if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 585                                 bth0 |= IB_BTH_SOLICITED;
 586                 }
 587                 bth2 |= IB_BTH_REQ_ACK;
 588                 qp->s_cur++;
 589                 if (qp->s_cur >= qp->s_size)
 590                         qp->s_cur = 0;
 591                 break;
 592
 593         case OP(RDMA_READ_RESPONSE_MIDDLE):
 594                 /*
 595                  * qp->s_state is normally set to the opcode of the
 596                  * last packet constructed for new requests and therefore
 597                  * is never set to RDMA read response.
 598                  * RDMA_READ_RESPONSE_MIDDLE is used by the ACK processing
 599                  * thread to indicate a RDMA read needs to be restarted from
 600                  * an earlier PSN without interferring with the sending thread.
 601                  * See qib_restart_rc().
 602                  */
 603                 len = ((qp->s_psn - wqe->psn) & QIB_PSN_MASK) * pmtu;
 604                 ohdr->u.rc.reth.vaddr =
 605                         cpu_to_be64(wqe->wr.wr.rdma.remote_addr + len);
 606                 ohdr->u.rc.reth.rkey =
 607                         cpu_to_be32(wqe->wr.wr.rdma.rkey);
 608                 ohdr->u.rc.reth.length = cpu_to_be32(wqe->length - len);
 609                 qp->s_state = OP(RDMA_READ_REQUEST);
 610                 hwords += sizeof(ohdr->u.rc.reth) / sizeof(u32);
 611                 bth2 = (qp->s_psn & QIB_PSN_MASK) | IB_BTH_REQ_ACK;
 612                 qp->s_psn = wqe->lpsn + 1;
 613                 ss = NULL;
 614                 len = 0;
 615                 qp->s_cur++;
 616                 if (qp->s_cur == qp->s_size)
 617                         qp->s_cur = 0;
 618                 break;
 619         }
 620         qp->s_sending_hpsn = bth2;
 621         delta = (((int) bth2 - (int) wqe->psn) << 8) >> 8;
 622         if (delta && delta % QIB_PSN_CREDIT == 0)
 623                 bth2 |= IB_BTH_REQ_ACK;
 624         if (qp->s_flags & QIB_S_SEND_ONE) {
 625                 qp->s_flags &= ~QIB_S_SEND_ONE;
 626                 qp->s_flags |= QIB_S_WAIT_ACK;
 627                 bth2 |= IB_BTH_REQ_ACK;
 628         }
 629         qp->s_len -= len;
 630         qp->s_hdrwords = hwords;
 631         qp->s_cur_sge = ss;
 632         qp->s_cur_size = len;
 633         qib_make_ruc_header(qp, ohdr, bth0 | (qp->s_state << 24), bth2);
 634 done:
 635         ret = 1;
 636         goto unlock;
 637
 638 bail:
 639         qp->s_flags &= ~QIB_S_BUSY;
 640 unlock:
 641         spin_unlock_irqrestore(&qp->s_lock, flags);
 642         return ret;
 643 }
 644
 645 /**
 646  * qib_send_rc_ack - Construct an ACK packet and send it
 647  * @qp: a pointer to the QP
 648  *
 649  * This is called from qib_rc_rcv() and qib_kreceive().
 650  * Note that RDMA reads and atomics are handled in the
 651  * send side QP state and tasklet.
 652  */
 653 void qib_send_rc_ack(struct qib_qp *qp)
 654 {
 655         struct qib_devdata *dd = dd_from_ibdev(qp->ibqp.device);
 656         struct qib_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
 657         struct qib_pportdata *ppd = ppd_from_ibp(ibp);
 658         u64 pbc;
 659         u16 lrh0;
 660         u32 bth0;
 661         u32 hwords;
 662         u32 pbufn;
 663         u32 __iomem *piobuf;
 664         struct qib_ib_header hdr;
 665         struct qib_other_headers *ohdr;
 666         u32 control;
 667         unsigned long flags;
 668
 669         spin_lock_irqsave(&qp->s_lock, flags);
 670
 671         if (!(ib_qib_state_ops[qp->state] & QIB_PROCESS_RECV_OK))
 672                 goto unlock;
 673
 674         /* Don't send ACK or NAK if a RDMA read or atomic is pending. */
 675         if ((qp->s_flags & QIB_S_RESP_PENDING) || qp->s_rdma_ack_cnt)
 676                 goto queue_ack;
 677
 678         /* Construct the header with s_lock held so APM doesn't change it. */
 679         ohdr = &hdr.u.oth;
 680         lrh0 = QIB_LRH_BTH;
 681         /* header size in 32-bit words LRH+BTH+AETH = (8+12+4)/4. */
 682         hwords = 6;
 683         if (unlikely(qp->remote_ah_attr.ah_flags & IB_AH_GRH)) {
 684                 hwords += qib_make_grh(ibp, &hdr.u.l.grh,
 685                                        &qp->remote_ah_attr.grh, hwords, 0);
 686                 ohdr = &hdr.u.l.oth;
 687                 lrh0 = QIB_LRH_GRH;
 688         }
 689         /* read pkey_index w/o lock (its atomic) */
 690         bth0 = qib_get_pkey(ibp, qp->s_pkey_index) | (OP(ACKNOWLEDGE) << 24);
 691         if (qp->s_mig_state == IB_MIG_MIGRATED)
 692                 bth0 |= IB_BTH_MIG_REQ;
 693         if (qp->r_nak_state)
 694                 ohdr->u.aeth = cpu_to_be32((qp->r_msn & QIB_MSN_MASK) |
 695                                             (qp->r_nak_state <<
 696                                              QIB_AETH_CREDIT_SHIFT));
 697         else
 698                 ohdr->u.aeth = qib_compute_aeth(qp);
 699         lrh0 |= ibp->sl_to_vl[qp->remote_ah_attr.sl] << 12 |
 700                 qp->remote_ah_attr.sl << 4;
 701         hdr.lrh[0] = cpu_to_be16(lrh0);
 702         hdr.lrh[1] = cpu_to_be16(qp->remote_ah_attr.dlid);
 703         hdr.lrh[2] = cpu_to_be16(hwords + SIZE_OF_CRC);
 704         hdr.lrh[3] = cpu_to_be16(ppd->lid | qp->remote_ah_attr.src_path_bits);
 705         ohdr->bth[0] = cpu_to_be32(bth0);
 706         ohdr->bth[1] = cpu_to_be32(qp->remote_qpn);
 707         ohdr->bth[2] = cpu_to_be32(qp->r_ack_psn & QIB_PSN_MASK);
 708
 709         spin_unlock_irqrestore(&qp->s_lock, flags);
 710
 711         /* Don't try to send ACKs if the link isn't ACTIVE */
 712         if (!(ppd->lflags & QIBL_LINKACTIVE))
 713                 goto done;
 714
 715         control = dd->f_setpbc_control(ppd, hwords + SIZE_OF_CRC,
 716                                        qp->s_srate, lrh0 >> 12);
 717         /* length is + 1 for the control dword */
 718         pbc = ((u64) control << 32) | (hwords + 1);
 719
 720         piobuf = dd->f_getsendbuf(ppd, pbc, &pbufn);
 721         if (!piobuf) {
 722                 /*
 723                  * We are out of PIO buffers at the moment.
 724                  * Pass responsibility for sending the ACK to the
 725                  * send tasklet so that when a PIO buffer becomes
 726                  * available, the ACK is sent ahead of other outgoing
 727                  * packets.
 728                  */
 729                 spin_lock_irqsave(&qp->s_lock, flags);
 730                 goto queue_ack;
 731         }
 732
 733         /*
 734          * Write the pbc.
 735          * We have to flush after the PBC for correctness
 736          * on some cpus or WC buffer can be written out of order.
 737          */
 738         writeq(pbc, piobuf);
 739
 740         if (dd->flags & QIB_PIO_FLUSH_WC) {
 741                 u32 *hdrp = (u32 *) &hdr;
 742
 743                 qib_flush_wc();
 744                 qib_pio_copy(piobuf + 2, hdrp, hwords - 1);
 745                 qib_flush_wc();
 746                 __raw_writel(hdrp[hwords - 1], piobuf + hwords + 1);
 747         } else
 748                 qib_pio_copy(piobuf + 2, (u32 *) &hdr, hwords);
 749
 750         if (dd->flags & QIB_USE_SPCL_TRIG) {
 751                 u32 spcl_off = (pbufn >= dd->piobcnt2k) ? 2047 : 1023;
 752
 753                 qib_flush_wc();
 754                 __raw_writel(0xaebecede, piobuf + spcl_off);
 755         }
 756
 757         qib_flush_wc();
 758         qib_sendbuf_done(dd, pbufn);
 759
 760         ibp->n_unicast_xmit++;
 761         goto done;
 762
 763 queue_ack:
 764         if (ib_qib_state_ops[qp->state] & QIB_PROCESS_RECV_OK) {
 765                 ibp->n_rc_qacks++;
 766                 qp->s_flags |= QIB_S_ACK_PENDING | QIB_S_RESP_PENDING;
 767                 qp->s_nak_state = qp->r_nak_state;
 768                 qp->s_ack_psn = qp->r_ack_psn;
 769
 770                 /* Schedule the send tasklet. */
 771                 qib_schedule_send(qp);
 772         }
 773 unlock:
 774         spin_unlock_irqrestore(&qp->s_lock, flags);
 775 done:
 776         return;
 777 }
 778
 779 /**
 780  * reset_psn - reset the QP state to send starting from PSN
 781  * @qp: the QP
 782  * @psn: the packet sequence number to restart at
 783  *
 784  * This is called from qib_rc_rcv() to process an incoming RC ACK
 785  * for the given QP.
 786  * Called at interrupt level with the QP s_lock held.
 787  */
 788 static void reset_psn(struct qib_qp *qp, u32 psn)
 789 {
 790         u32 n = qp->s_acked;
 791         struct qib_swqe *wqe = get_swqe_ptr(qp, n);
 792         u32 opcode;
 793
 794         qp->s_cur = n;
 795
 796         /*
 797          * If we are starting the request from the beginning,
 798          * let the normal send code handle initialization.
 799          */
 800         if (qib_cmp24(psn, wqe->psn) <= 0) {
 801                 qp->s_state = OP(SEND_LAST);
 802                 goto done;
 803         }
 804
 805         /* Find the work request opcode corresponding to the given PSN. */
 806         opcode = wqe->wr.opcode;
 807         for (;;) {
 808                 int diff;
 809
 810                 if (++n == qp->s_size)
 811                         n = 0;
 812                 if (n == qp->s_tail)
 813                         break;
 814                 wqe = get_swqe_ptr(qp, n);
 815                 diff = qib_cmp24(psn, wqe->psn);
 816                 if (diff < 0)
 817                         break;
 818                 qp->s_cur = n;
 819                 /*
 820                  * If we are starting the request from the beginning,
 821                  * let the normal send code handle initialization.
 822                  */
 823                 if (diff == 0) {
 824                         qp->s_state = OP(SEND_LAST);
 825                         goto done;
 826                 }
 827                 opcode = wqe->wr.opcode;
 828         }
 829
 830         /*
 831          * Set the state to restart in the middle of a request.
 832          * Don't change the s_sge, s_cur_sge, or s_cur_size.
 833          * See qib_make_rc_req().
 834          */
 835         switch (opcode) {
 836         case IB_WR_SEND:
 837         case IB_WR_SEND_WITH_IMM:
 838                 qp->s_state = OP(RDMA_READ_RESPONSE_FIRST);
 839                 break;
 840
 841         case IB_WR_RDMA_WRITE:
 842         case IB_WR_RDMA_WRITE_WITH_IMM:
 843                 qp->s_state = OP(RDMA_READ_RESPONSE_LAST);
 844                 break;
 845
 846         case IB_WR_RDMA_READ:
 847                 qp->s_state = OP(RDMA_READ_RESPONSE_MIDDLE);
 848                 break;
 849
 850         default:
 851                 /*
 852                  * This case shouldn't happen since its only
 853                  * one PSN per req.
 854                  */
 855                 qp->s_state = OP(SEND_LAST);
 856         }
 857 done:
 858         qp->s_psn = psn;
 859         /*
 860          * Set QIB_S_WAIT_PSN as qib_rc_complete() may start the timer
 861          * asynchronously before the send tasklet can get scheduled.
 862          * Doing it in qib_make_rc_req() is too late.
 863          */
 864         if ((qib_cmp24(qp->s_psn, qp->s_sending_hpsn) <= 0) &&
 865             (qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) <= 0))
 866                 qp->s_flags |= QIB_S_WAIT_PSN;
 867 }
 868
 869 /*
 870  * Back up requester to resend the last un-ACKed request.
 871  * The QP s_lock should be held and interrupts disabled.
 872  */
 873 static void qib_restart_rc(struct qib_qp *qp, u32 psn, int wait)
 874 {
 875         struct qib_swqe *wqe = get_swqe_ptr(qp, qp->s_acked);
 876         struct qib_ibport *ibp;
 877
 878         if (qp->s_retry == 0) {
 879                 if (qp->s_mig_state == IB_MIG_ARMED) {
 880                         qib_migrate_qp(qp);
 881                         qp->s_retry = qp->s_retry_cnt;
 882                 } else if (qp->s_last == qp->s_acked) {
 883                         qib_send_complete(qp, wqe, IB_WC_RETRY_EXC_ERR);
 884                         qib_error_qp(qp, IB_WC_WR_FLUSH_ERR);
 885                         return;
 886                 } else /* XXX need to handle delayed completion */
 887                         return;
 888         } else
 889                 qp->s_retry--;
 890
 891         ibp = to_iport(qp->ibqp.device, qp->port_num);
 892         if (wqe->wr.opcode == IB_WR_RDMA_READ)
 893                 ibp->n_rc_resends++;
 894         else
 895                 ibp->n_rc_resends += (qp->s_psn - psn) & QIB_PSN_MASK;
 896
 897         qp->s_flags &= ~(QIB_S_WAIT_FENCE | QIB_S_WAIT_RDMAR |
 898                          QIB_S_WAIT_SSN_CREDIT | QIB_S_WAIT_PSN |
 899                          QIB_S_WAIT_ACK);
 900         if (wait)
 901                 qp->s_flags |= QIB_S_SEND_ONE;
 902         reset_psn(qp, psn);
 903 }
 904
 905 /*
 906  * This is called from s_timer for missing responses.
 907  */
 908 static void rc_timeout(unsigned long arg)
 909 {
 910         struct qib_qp *qp = (struct qib_qp *)arg;
 911         struct qib_ibport *ibp;
 912         unsigned long flags;
 913
 914         spin_lock_irqsave(&qp->s_lock, flags);
 915         if (qp->s_flags & QIB_S_TIMER) {
 916                 ibp = to_iport(qp->ibqp.device, qp->port_num);
 917                 ibp->n_rc_timeouts++;
 918                 qp->s_flags &= ~QIB_S_TIMER;
 919                 del_timer(&qp->s_timer);
 920                 qib_restart_rc(qp, qp->s_last_psn + 1, 1);
 921                 qib_schedule_send(qp);
 922         }
 923         spin_unlock_irqrestore(&qp->s_lock, flags);
 924 }
 925
 926 /*
 927  * This is called from s_timer for RNR timeouts.
 928  */
 929 void qib_rc_rnr_retry(unsigned long arg)
 930 {
 931         struct qib_qp *qp = (struct qib_qp *)arg;
 932         unsigned long flags;
 933
 934         spin_lock_irqsave(&qp->s_lock, flags);
 935         if (qp->s_flags & QIB_S_WAIT_RNR) {
 936                 qp->s_flags &= ~QIB_S_WAIT_RNR;
 937                 del_timer(&qp->s_timer);
 938                 qib_schedule_send(qp);
 939         }
 940         spin_unlock_irqrestore(&qp->s_lock, flags);
 941 }
 942
 943 /*
 944  * Set qp->s_sending_psn to the next PSN after the given one.
 945  * This would be psn+1 except when RDMA reads are present.
 946  */
 947 static void reset_sending_psn(struct qib_qp *qp, u32 psn)
 948 {
 949         struct qib_swqe *wqe;
 950         u32 n = qp->s_last;
 951
 952         /* Find the work request corresponding to the given PSN. */
 953         for (;;) {
 954                 wqe = get_swqe_ptr(qp, n);
 955                 if (qib_cmp24(psn, wqe->lpsn) <= 0) {
 956                         if (wqe->wr.opcode == IB_WR_RDMA_READ)
 957                                 qp->s_sending_psn = wqe->lpsn + 1;
 958                         else
 959                                 qp->s_sending_psn = psn + 1;
 960                         break;
 961                 }
 962                 if (++n == qp->s_size)
 963                         n = 0;
 964                 if (n == qp->s_tail)
 965                         break;
 966         }
 967 }
 968
 969 /*
 970  * This should be called with the QP s_lock held and interrupts disabled.
 971  */
 972 void qib_rc_send_complete(struct qib_qp *qp, struct qib_ib_header *hdr)
 973 {
 974         struct qib_other_headers *ohdr;
 975         struct qib_swqe *wqe;
 976         struct ib_wc wc;
 977         unsigned i;
 978         u32 opcode;
 979         u32 psn;
 980
 981         if (!(ib_qib_state_ops[qp->state] & QIB_PROCESS_OR_FLUSH_SEND))
 982                 return;
 983
 984         /* Find out where the BTH is */
 985         if ((be16_to_cpu(hdr->lrh[0]) & 3) == QIB_LRH_BTH)
 986                 ohdr = &hdr->u.oth;
 987         else
 988                 ohdr = &hdr->u.l.oth;
 989
 990         opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
 991         if (opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
 992             opcode <= OP(ATOMIC_ACKNOWLEDGE)) {
 993                 WARN_ON(!qp->s_rdma_ack_cnt);
 994                 qp->s_rdma_ack_cnt--;
 995                 return;
 996         }
 997
 998         psn = be32_to_cpu(ohdr->bth[2]);
 999         reset_sending_psn(qp, psn);
1000
1001         /*
1002          * Start timer after a packet requesting an ACK has been sent and
1003          * there are still requests that haven't been acked.
1004          */
1005         if ((psn & IB_BTH_REQ_ACK) && qp->s_acked != qp->s_tail &&
1006             !(qp->s_flags & (QIB_S_TIMER | QIB_S_WAIT_RNR | QIB_S_WAIT_PSN)))
1007                 start_timer(qp);
1008
1009         while (qp->s_last != qp->s_acked) {
1010                 wqe = get_swqe_ptr(qp, qp->s_last);
1011                 if (qib_cmp24(wqe->lpsn, qp->s_sending_psn) >= 0 &&
1012                     qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) <= 0)
1013                         break;
1014                 for (i = 0; i < wqe->wr.num_sge; i++) {
1015                         struct qib_sge *sge = &wqe->sg_list[i];
1016
1017                         atomic_dec(&sge->mr->refcount);
1018                 }
1019                 /* Post a send completion queue entry if requested. */
1020                 if (!(qp->s_flags & QIB_S_SIGNAL_REQ_WR) ||
1021                     (wqe->wr.send_flags & IB_SEND_SIGNALED)) {
1022                         memset(&wc, 0, sizeof wc);
1023                         wc.wr_id = wqe->wr.wr_id;
1024                         wc.status = IB_WC_SUCCESS;
1025                         wc.opcode = ib_qib_wc_opcode[wqe->wr.opcode];
1026                         wc.byte_len = wqe->length;
1027                         wc.qp = &qp->ibqp;
1028                         qib_cq_enter(to_icq(qp->ibqp.send_cq), &wc, 0);
1029                 }
1030                 if (++qp->s_last >= qp->s_size)
1031                         qp->s_last = 0;
1032         }
1033         /*
1034          * If we were waiting for sends to complete before resending,
1035          * and they are now complete, restart sending.
1036          */
1037         if (qp->s_flags & QIB_S_WAIT_PSN &&
1038             qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) > 0) {
1039                 qp->s_flags &= ~QIB_S_WAIT_PSN;
1040                 qp->s_sending_psn = qp->s_psn;
1041                 qp->s_sending_hpsn = qp->s_psn - 1;
1042                 qib_schedule_send(qp);
1043         }
1044 }
1045
1046 static inline void update_last_psn(struct qib_qp *qp, u32 psn)
1047 {
1048         qp->s_last_psn = psn;
1049 }
1050
1051 /*
1052  * Generate a SWQE completion.
1053  * This is similar to qib_send_complete but has to check to be sure
1054  * that the SGEs are not being referenced if the SWQE is being resent.
1055  */
1056 static struct qib_swqe *do_rc_completion(struct qib_qp *qp,
1057                                          struct qib_swqe *wqe,
1058                                          struct qib_ibport *ibp)
1059 {
1060         struct ib_wc wc;
1061         unsigned i;
1062
1063         /*
1064          * Don't decrement refcount and don't generate a
1065          * completion if the SWQE is being resent until the send
1066          * is finished.
1067          */
1068         if (qib_cmp24(wqe->lpsn, qp->s_sending_psn) < 0 ||
1069             qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) > 0) {
1070                 for (i = 0; i < wqe->wr.num_sge; i++) {
1071                         struct qib_sge *sge = &wqe->sg_list[i];
1072
1073                         atomic_dec(&sge->mr->refcount);
1074                 }
1075                 /* Post a send completion queue entry if requested. */
1076                 if (!(qp->s_flags & QIB_S_SIGNAL_REQ_WR) ||
1077                     (wqe->wr.send_flags & IB_SEND_SIGNALED)) {
1078                         memset(&wc, 0, sizeof wc);
1079                         wc.wr_id = wqe->wr.wr_id;
1080                         wc.status = IB_WC_SUCCESS;
1081                         wc.opcode = ib_qib_wc_opcode[wqe->wr.opcode];
1082                         wc.byte_len = wqe->length;
1083                         wc.qp = &qp->ibqp;
1084                         qib_cq_enter(to_icq(qp->ibqp.send_cq), &wc, 0);
1085                 }
1086                 if (++qp->s_last >= qp->s_size)
1087                         qp->s_last = 0;
1088         } else
1089                 ibp->n_rc_delayed_comp++;
1090
1091         qp->s_retry = qp->s_retry_cnt;
1092         update_last_psn(qp, wqe->lpsn);
1093
1094         /*
1095          * If we are completing a request which is in the process of
1096          * being resent, we can stop resending it since we know the
1097          * responder has already seen it.
1098          */
1099         if (qp->s_acked == qp->s_cur) {
1100                 if (++qp->s_cur >= qp->s_size)
1101                         qp->s_cur = 0;
1102                 qp->s_acked = qp->s_cur;
1103                 wqe = get_swqe_ptr(qp, qp->s_cur);
1104                 if (qp->s_acked != qp->s_tail) {
1105                         qp->s_state = OP(SEND_LAST);
1106                         qp->s_psn = wqe->psn;
1107                 }
1108         } else {
1109                 if (++qp->s_acked >= qp->s_size)
1110                         qp->s_acked = 0;
1111                 if (qp->state == IB_QPS_SQD && qp->s_acked == qp->s_cur)
1112                         qp->s_draining = 0;
1113                 wqe = get_swqe_ptr(qp, qp->s_acked);
1114         }
1115         return wqe;
1116 }
1117
1118 /**
1119  * do_rc_ack - process an incoming RC ACK
1120  * @qp: the QP the ACK came in on
1121  * @psn: the packet sequence number of the ACK
1122  * @opcode: the opcode of the request that resulted in the ACK
1123  *
1124  * This is called from qib_rc_rcv_resp() to process an incoming RC ACK
1125  * for the given QP.
1126  * Called at interrupt level with the QP s_lock held.
1127  * Returns 1 if OK, 0 if current operation should be aborted (NAK).
1128  */
1129 static int do_rc_ack(struct qib_qp *qp, u32 aeth, u32 psn, int opcode,
1130                      u64 val, struct qib_ctxtdata *rcd)
1131 {
1132         struct qib_ibport *ibp;
1133         enum ib_wc_status status;
1134         struct qib_swqe *wqe;
1135         int ret = 0;
1136         u32 ack_psn;
1137         int diff;
1138
1139         /* Remove QP from retry timer */
1140         if (qp->s_flags & (QIB_S_TIMER | QIB_S_WAIT_RNR)) {
1141                 qp->s_flags &= ~(QIB_S_TIMER | QIB_S_WAIT_RNR);
1142                 del_timer(&qp->s_timer);
1143         }
1144
1145         /*
1146          * Note that NAKs implicitly ACK outstanding SEND and RDMA write
1147          * requests and implicitly NAK RDMA read and atomic requests issued
1148          * before the NAK'ed request.  The MSN won't include the NAK'ed
1149          * request but will include an ACK'ed request(s).
1150          */
1151         ack_psn = psn;
1152         if (aeth >> 29)
1153                 ack_psn--;
1154         wqe = get_swqe_ptr(qp, qp->s_acked);
1155         ibp = to_iport(qp->ibqp.device, qp->port_num);
1156
1157         /*
1158          * The MSN might be for a later WQE than the PSN indicates so
1159          * only complete WQEs that the PSN finishes.
1160          */
1161         while ((diff = qib_cmp24(ack_psn, wqe->lpsn)) >= 0) {
1162                 /*
1163                  * RDMA_READ_RESPONSE_ONLY is a special case since
1164                  * we want to generate completion events for everything
1165                  * before the RDMA read, copy the data, then generate
1166                  * the completion for the read.
1167                  */
1168                 if (wqe->wr.opcode == IB_WR_RDMA_READ &&
1169                     opcode == OP(RDMA_READ_RESPONSE_ONLY) &&
1170                     diff == 0) {
1171                         ret = 1;
1172                         goto bail;
1173                 }
1174                 /*
1175                  * If this request is a RDMA read or atomic, and the ACK is
1176                  * for a later operation, this ACK NAKs the RDMA read or
1177                  * atomic.  In other words, only a RDMA_READ_LAST or ONLY
1178                  * can ACK a RDMA read and likewise for atomic ops.  Note
1179                  * that the NAK case can only happen if relaxed ordering is
1180                  * used and requests are sent after an RDMA read or atomic
1181                  * is sent but before the response is received.
1182                  */
1183                 if ((wqe->wr.opcode == IB_WR_RDMA_READ &&
1184                      (opcode != OP(RDMA_READ_RESPONSE_LAST) || diff != 0)) ||
1185                     ((wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1186                       wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) &&
1187                      (opcode != OP(ATOMIC_ACKNOWLEDGE) || diff != 0))) {
1188                         /* Retry this request. */
1189                         if (!(qp->r_flags & QIB_R_RDMAR_SEQ)) {
1190                                 qp->r_flags |= QIB_R_RDMAR_SEQ;
1191                                 qib_restart_rc(qp, qp->s_last_psn + 1, 0);
1192                                 if (list_empty(&qp->rspwait)) {
1193                                         qp->r_flags |= QIB_R_RSP_SEND;
1194                                         atomic_inc(&qp->refcount);
1195                                         list_add_tail(&qp->rspwait,
1196                                                       &rcd->qp_wait_list);
1197                                 }
1198                         }
1199                         /*
1200                          * No need to process the ACK/NAK since we are
1201                          * restarting an earlier request.
1202                          */
1203                         goto bail;
1204                 }
1205                 if (wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1206                     wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) {
1207                         u64 *vaddr = wqe->sg_list[0].vaddr;
1208                         *vaddr = val;
1209                 }
1210                 if (qp->s_num_rd_atomic &&
1211                     (wqe->wr.opcode == IB_WR_RDMA_READ ||
1212                      wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1213                      wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)) {
1214                         qp->s_num_rd_atomic--;
1215                         /* Restart sending task if fence is complete */
1216                         if ((qp->s_flags & QIB_S_WAIT_FENCE) &&
1217                             !qp->s_num_rd_atomic) {
1218                                 qp->s_flags &= ~(QIB_S_WAIT_FENCE |
1219                                                  QIB_S_WAIT_ACK);
1220                                 qib_schedule_send(qp);
1221                         } else if (qp->s_flags & QIB_S_WAIT_RDMAR) {
1222                                 qp->s_flags &= ~(QIB_S_WAIT_RDMAR |
1223                                                  QIB_S_WAIT_ACK);
1224                                 qib_schedule_send(qp);
1225                         }
1226                 }
1227                 wqe = do_rc_completion(qp, wqe, ibp);
1228                 if (qp->s_acked == qp->s_tail)
1229                         break;
1230         }
1231
1232         switch (aeth >> 29) {
1233         case 0:         /* ACK */
1234                 ibp->n_rc_acks++;
1235                 if (qp->s_acked != qp->s_tail) {
1236                         /*
1237                          * We are expecting more ACKs so
1238                          * reset the retransmit timer.
1239                          */
1240                         start_timer(qp);
1241                         /*
1242                          * We can stop resending the earlier packets and
1243                          * continue with the next packet the receiver wants.
1244                          */
1245                         if (qib_cmp24(qp->s_psn, psn) <= 0)
1246                                 reset_psn(qp, psn + 1);
1247                 } else if (qib_cmp24(qp->s_psn, psn) <= 0) {
1248                         qp->s_state = OP(SEND_LAST);
1249                         qp->s_psn = psn + 1;
1250                 }
1251                 if (qp->s_flags & QIB_S_WAIT_ACK) {
1252                         qp->s_flags &= ~QIB_S_WAIT_ACK;
1253                         qib_schedule_send(qp);
1254                 }
1255                 qib_get_credit(qp, aeth);
1256                 qp->s_rnr_retry = qp->s_rnr_retry_cnt;
1257                 qp->s_retry = qp->s_retry_cnt;
1258                 update_last_psn(qp, psn);
1259                 ret = 1;
1260                 goto bail;
1261
1262         case 1:         /* RNR NAK */
1263                 ibp->n_rnr_naks++;
1264                 if (qp->s_acked == qp->s_tail)
1265                         goto bail;
1266                 if (qp->s_flags & QIB_S_WAIT_RNR)
1267                         goto bail;
1268                 if (qp->s_rnr_retry == 0) {
1269                         status = IB_WC_RNR_RETRY_EXC_ERR;
1270                         goto class_b;
1271                 }
1272                 if (qp->s_rnr_retry_cnt < 7)
1273                         qp->s_rnr_retry--;
1274
1275                 /* The last valid PSN is the previous PSN. */
1276                 update_last_psn(qp, psn - 1);
1277
1278                 ibp->n_rc_resends += (qp->s_psn - psn) & QIB_PSN_MASK;
1279
1280                 reset_psn(qp, psn);
1281
1282                 qp->s_flags &= ~(QIB_S_WAIT_SSN_CREDIT | QIB_S_WAIT_ACK);
1283                 qp->s_flags |= QIB_S_WAIT_RNR;
1284                 qp->s_timer.function = qib_rc_rnr_retry;
1285                 qp->s_timer.expires = jiffies + usecs_to_jiffies(
1286                         ib_qib_rnr_table[(aeth >> QIB_AETH_CREDIT_SHIFT) &
1287                                            QIB_AETH_CREDIT_MASK]);
1288                 add_timer(&qp->s_timer);
1289                 goto bail;
1290
1291         case 3:         /* NAK */
1292                 if (qp->s_acked == qp->s_tail)
1293                         goto bail;
1294                 /* The last valid PSN is the previous PSN. */
1295                 update_last_psn(qp, psn - 1);
1296                 switch ((aeth >> QIB_AETH_CREDIT_SHIFT) &
1297                         QIB_AETH_CREDIT_MASK) {
1298                 case 0: /* PSN sequence error */
1299                         ibp->n_seq_naks++;
1300                         /*
1301                          * Back up to the responder's expected PSN.
1302                          * Note that we might get a NAK in the middle of an
1303                          * RDMA READ response which terminates the RDMA
1304                          * READ.
1305                          */
1306                         qib_restart_rc(qp, psn, 0);
1307                         qib_schedule_send(qp);
1308                         break;
1309
1310                 case 1: /* Invalid Request */
1311                         status = IB_WC_REM_INV_REQ_ERR;
1312                         ibp->n_other_naks++;
1313                         goto class_b;
1314
1315                 case 2: /* Remote Access Error */
1316                         status = IB_WC_REM_ACCESS_ERR;
1317                         ibp->n_other_naks++;
1318                         goto class_b;
1319
1320                 case 3: /* Remote Operation Error */
1321                         status = IB_WC_REM_OP_ERR;
1322                         ibp->n_other_naks++;
1323 class_b:
1324                         if (qp->s_last == qp->s_acked) {
1325                                 qib_send_complete(qp, wqe, status);
1326                                 qib_error_qp(qp, IB_WC_WR_FLUSH_ERR);
1327                         }
1328                         break;
1329
1330                 default:
1331                         /* Ignore other reserved NAK error codes */
1332                         goto reserved;
1333                 }
1334                 qp->s_retry = qp->s_retry_cnt;
1335                 qp->s_rnr_retry = qp->s_rnr_retry_cnt;
1336                 goto bail;
1337
1338         default:                /* 2: reserved */
1339 reserved:
1340                 /* Ignore reserved NAK codes. */
1341                 goto bail;
1342         }
1343
1344 bail:
1345         return ret;
1346 }
1347
1348 /*
1349  * We have seen an out of sequence RDMA read middle or last packet.
1350  * This ACKs SENDs and RDMA writes up to the first RDMA read or atomic SWQE.
1351  */
1352 static void rdma_seq_err(struct qib_qp *qp, struct qib_ibport *ibp, u32 psn,
1353                          struct qib_ctxtdata *rcd)
1354 {
1355         struct qib_swqe *wqe;
1356
1357         /* Remove QP from retry timer */
1358         if (qp->s_flags & (QIB_S_TIMER | QIB_S_WAIT_RNR)) {
1359                 qp->s_flags &= ~(QIB_S_TIMER | QIB_S_WAIT_RNR);
1360                 del_timer(&qp->s_timer);
1361         }
1362
1363         wqe = get_swqe_ptr(qp, qp->s_acked);
1364
1365         while (qib_cmp24(psn, wqe->lpsn) > 0) {
1366                 if (wqe->wr.opcode == IB_WR_RDMA_READ ||
1367                     wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1368                     wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)
1369                         break;
1370                 wqe = do_rc_completion(qp, wqe, ibp);
1371         }
1372
1373         ibp->n_rdma_seq++;
1374         qp->r_flags |= QIB_R_RDMAR_SEQ;
1375         qib_restart_rc(qp, qp->s_last_psn + 1, 0);
1376         if (list_empty(&qp->rspwait)) {
1377                 qp->r_flags |= QIB_R_RSP_SEND;
1378                 atomic_inc(&qp->refcount);
1379                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
1380         }
1381 }
1382
1383 /**
1384  * qib_rc_rcv_resp - process an incoming RC response packet
1385  * @ibp: the port this packet came in on
1386  * @ohdr: the other headers for this packet
1387  * @data: the packet data
1388  * @tlen: the packet length
1389  * @qp: the QP for this packet
1390  * @opcode: the opcode for this packet
1391  * @psn: the packet sequence number for this packet
1392  * @hdrsize: the header length
1393  * @pmtu: the path MTU
1394  *
1395  * This is called from qib_rc_rcv() to process an incoming RC response
1396  * packet for the given QP.
1397  * Called at interrupt level.
1398  */
1399 static void qib_rc_rcv_resp(struct qib_ibport *ibp,
1400                             struct qib_other_headers *ohdr,
1401                             void *data, u32 tlen,
1402                             struct qib_qp *qp,
1403                             u32 opcode,
1404                             u32 psn, u32 hdrsize, u32 pmtu,
1405                             struct qib_ctxtdata *rcd)
1406 {
1407         struct qib_swqe *wqe;
1408         enum ib_wc_status status;
1409         unsigned long flags;
1410         int diff;
1411         u32 pad;
1412         u32 aeth;
1413         u64 val;
1414
1415         spin_lock_irqsave(&qp->s_lock, flags);
1416
1417         /* Double check we can process this now that we hold the s_lock. */
1418         if (!(ib_qib_state_ops[qp->state] & QIB_PROCESS_RECV_OK))
1419                 goto ack_done;
1420
1421         /* Ignore invalid responses. */
1422         if (qib_cmp24(psn, qp->s_next_psn) >= 0)
1423                 goto ack_done;
1424
1425         /* Ignore duplicate responses. */
1426         diff = qib_cmp24(psn, qp->s_last_psn);
1427         if (unlikely(diff <= 0)) {
1428                 /* Update credits for "ghost" ACKs */
1429                 if (diff == 0 && opcode == OP(ACKNOWLEDGE)) {
1430                         aeth = be32_to_cpu(ohdr->u.aeth);
1431                         if ((aeth >> 29) == 0)
1432                                 qib_get_credit(qp, aeth);
1433                 }
1434                 goto ack_done;
1435         }
1436
1437         /*
1438          * Skip everything other than the PSN we expect, if we are waiting
1439          * for a reply to a restarted RDMA read or atomic op.
1440          */
1441         if (qp->r_flags & QIB_R_RDMAR_SEQ) {
1442                 if (qib_cmp24(psn, qp->s_last_psn + 1) != 0)
1443                         goto ack_done;
1444                 qp->r_flags &= ~QIB_R_RDMAR_SEQ;
1445         }
1446
1447         if (unlikely(qp->s_acked == qp->s_tail))
1448                 goto ack_done;
1449         wqe = get_swqe_ptr(qp, qp->s_acked);
1450         status = IB_WC_SUCCESS;
1451
1452         switch (opcode) {
1453         case OP(ACKNOWLEDGE):
1454         case OP(ATOMIC_ACKNOWLEDGE):
1455         case OP(RDMA_READ_RESPONSE_FIRST):
1456                 aeth = be32_to_cpu(ohdr->u.aeth);
1457                 if (opcode == OP(ATOMIC_ACKNOWLEDGE)) {
1458                         __be32 *p = ohdr->u.at.atomic_ack_eth;
1459
1460                         val = ((u64) be32_to_cpu(p[0]) << 32) |
1461                                 be32_to_cpu(p[1]);
1462                 } else
1463                         val = 0;
1464                 if (!do_rc_ack(qp, aeth, psn, opcode, val, rcd) ||
1465                     opcode != OP(RDMA_READ_RESPONSE_FIRST))
1466                         goto ack_done;
1467                 hdrsize += 4;
1468                 wqe = get_swqe_ptr(qp, qp->s_acked);
1469                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1470                         goto ack_op_err;
1471                 /*
1472                  * If this is a response to a resent RDMA read, we
1473                  * have to be careful to copy the data to the right
1474                  * location.
1475                  */
1476                 qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
1477                                                   wqe, psn, pmtu);
1478                 goto read_middle;
1479
1480         case OP(RDMA_READ_RESPONSE_MIDDLE):
1481                 /* no AETH, no ACK */
1482                 if (unlikely(qib_cmp24(psn, qp->s_last_psn + 1)))
1483                         goto ack_seq_err;
1484                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1485                         goto ack_op_err;
1486 read_middle:
1487                 if (unlikely(tlen != (hdrsize + pmtu + 4)))
1488                         goto ack_len_err;
1489                 if (unlikely(pmtu >= qp->s_rdma_read_len))
1490                         goto ack_len_err;
1491
1492                 /*
1493                  * We got a response so update the timeout.
1494                  * 4.096 usec. * (1 << qp->timeout)
1495                  */
1496                 qp->s_flags |= QIB_S_TIMER;
1497                 mod_timer(&qp->s_timer, jiffies +
1498                         usecs_to_jiffies((4096UL * (1UL << qp->timeout)) /
1499                                          1000UL));
1500                 if (qp->s_flags & QIB_S_WAIT_ACK) {
1501                         qp->s_flags &= ~QIB_S_WAIT_ACK;
1502                         qib_schedule_send(qp);
1503                 }
1504
1505                 if (opcode == OP(RDMA_READ_RESPONSE_MIDDLE))
1506                         qp->s_retry = qp->s_retry_cnt;
1507
1508                 /*
1509                  * Update the RDMA receive state but do the copy w/o
1510                  * holding the locks and blocking interrupts.
1511                  */
1512                 qp->s_rdma_read_len -= pmtu;
1513                 update_last_psn(qp, psn);
1514                 spin_unlock_irqrestore(&qp->s_lock, flags);
1515                 qib_copy_sge(&qp->s_rdma_read_sge, data, pmtu, 0);
1516                 goto bail;
1517
1518         case OP(RDMA_READ_RESPONSE_ONLY):
1519                 aeth = be32_to_cpu(ohdr->u.aeth);
1520                 if (!do_rc_ack(qp, aeth, psn, opcode, 0, rcd))
1521                         goto ack_done;
1522                 /* Get the number of bytes the message was padded by. */
1523                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1524                 /*
1525                  * Check that the data size is >= 0 && <= pmtu.
1526                  * Remember to account for the AETH header (4) and
1527                  * ICRC (4).
1528                  */
1529                 if (unlikely(tlen < (hdrsize + pad + 8)))
1530                         goto ack_len_err;
1531                 /*
1532                  * If this is a response to a resent RDMA read, we
1533                  * have to be careful to copy the data to the right
1534                  * location.
1535                  */
1536                 wqe = get_swqe_ptr(qp, qp->s_acked);
1537                 qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
1538                                                   wqe, psn, pmtu);
1539                 goto read_last;
1540
1541         case OP(RDMA_READ_RESPONSE_LAST):
1542                 /* ACKs READ req. */
1543                 if (unlikely(qib_cmp24(psn, qp->s_last_psn + 1)))
1544                         goto ack_seq_err;
1545                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1546                         goto ack_op_err;
1547                 /* Get the number of bytes the message was padded by. */
1548                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1549                 /*
1550                  * Check that the data size is >= 1 && <= pmtu.
1551                  * Remember to account for the AETH header (4) and
1552                  * ICRC (4).
1553                  */
1554                 if (unlikely(tlen <= (hdrsize + pad + 8)))
1555                         goto ack_len_err;
1556 read_last:
1557                 tlen -= hdrsize + pad + 8;
1558                 if (unlikely(tlen != qp->s_rdma_read_len))
1559                         goto ack_len_err;
1560                 aeth = be32_to_cpu(ohdr->u.aeth);
1561                 qib_copy_sge(&qp->s_rdma_read_sge, data, tlen, 0);
1562                 WARN_ON(qp->s_rdma_read_sge.num_sge);
1563                 (void) do_rc_ack(qp, aeth, psn,
1564                                  OP(RDMA_READ_RESPONSE_LAST), 0, rcd);
1565                 goto ack_done;
1566         }
1567
1568 ack_op_err:
1569         status = IB_WC_LOC_QP_OP_ERR;
1570         goto ack_err;
1571
1572 ack_seq_err:
1573         rdma_seq_err(qp, ibp, psn, rcd);
1574         goto ack_done;
1575
1576 ack_len_err:
1577         status = IB_WC_LOC_LEN_ERR;
1578 ack_err:
1579         if (qp->s_last == qp->s_acked) {
1580                 qib_send_complete(qp, wqe, status);
1581                 qib_error_qp(qp, IB_WC_WR_FLUSH_ERR);
1582         }
1583 ack_done:
1584         spin_unlock_irqrestore(&qp->s_lock, flags);
1585 bail:
1586         return;
1587 }
1588
1589 /**
1590  * qib_rc_rcv_error - process an incoming duplicate or error RC packet
1591  * @ohdr: the other headers for this packet
1592  * @data: the packet data
1593  * @qp: the QP for this packet
1594  * @opcode: the opcode for this packet
1595  * @psn: the packet sequence number for this packet
1596  * @diff: the difference between the PSN and the expected PSN
1597  *
1598  * This is called from qib_rc_rcv() to process an unexpected
1599  * incoming RC packet for the given QP.
1600  * Called at interrupt level.
1601  * Return 1 if no more processing is needed; otherwise return 0 to
1602  * schedule a response to be sent.
1603  */
1604 static int qib_rc_rcv_error(struct qib_other_headers *ohdr,
1605                             void *data,
1606                             struct qib_qp *qp,
1607                             u32 opcode,
1608                             u32 psn,
1609                             int diff,
1610                             struct qib_ctxtdata *rcd)
1611 {
1612         struct qib_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
1613         struct qib_ack_entry *e;
1614         unsigned long flags;
1615         u8 i, prev;
1616         int old_req;
1617
1618         if (diff > 0) {
1619                 /*
1620                  * Packet sequence error.
1621                  * A NAK will ACK earlier sends and RDMA writes.
1622                  * Don't queue the NAK if we already sent one.
1623                  */
1624                 if (!qp->r_nak_state) {
1625                         ibp->n_rc_seqnak++;
1626                         qp->r_nak_state = IB_NAK_PSN_ERROR;
1627                         /* Use the expected PSN. */
1628                         qp->r_ack_psn = qp->r_psn;
1629                         /*
1630                          * Wait to send the sequence NAK until all packets
1631                          * in the receive queue have been processed.
1632                          * Otherwise, we end up propagating congestion.
1633                          */
1634                         if (list_empty(&qp->rspwait)) {
1635                                 qp->r_flags |= QIB_R_RSP_NAK;
1636                                 atomic_inc(&qp->refcount);
1637                                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
1638                         }
1639                 }
1640                 goto done;
1641         }
1642
1643         /*
1644          * Handle a duplicate request.  Don't re-execute SEND, RDMA
1645          * write or atomic op.  Don't NAK errors, just silently drop
1646          * the duplicate request.  Note that r_sge, r_len, and
1647          * r_rcv_len may be in use so don't modify them.
1648          *
1649          * We are supposed to ACK the earliest duplicate PSN but we
1650          * can coalesce an outstanding duplicate ACK.  We have to
1651          * send the earliest so that RDMA reads can be restarted at
1652          * the requester's expected PSN.
1653          *
1654          * First, find where this duplicate PSN falls within the
1655          * ACKs previously sent.
1656          * old_req is true if there is an older response that is scheduled
1657          * to be sent before sending this one.
1658          */
1659         e = NULL;
1660         old_req = 1;
1661         ibp->n_rc_dupreq++;
1662
1663         spin_lock_irqsave(&qp->s_lock, flags);
1664         /* Double check we can process this now that we hold the s_lock. */
1665         if (!(ib_qib_state_ops[qp->state] & QIB_PROCESS_RECV_OK))
1666                 goto unlock_done;
1667
1668         for (i = qp->r_head_ack_queue; ; i = prev) {
1669                 if (i == qp->s_tail_ack_queue)
1670                         old_req = 0;
1671                 if (i)
1672                         prev = i - 1;
1673                 else
1674                         prev = QIB_MAX_RDMA_ATOMIC;
1675                 if (prev == qp->r_head_ack_queue) {
1676                         e = NULL;
1677                         break;
1678                 }
1679                 e = &qp->s_ack_queue[prev];
1680                 if (!e->opcode) {
1681                         e = NULL;
1682                         break;
1683                 }
1684                 if (qib_cmp24(psn, e->psn) >= 0) {
1685                         if (prev == qp->s_tail_ack_queue &&
1686                             qib_cmp24(psn, e->lpsn) <= 0)
1687                                 old_req = 0;
1688                         break;
1689                 }
1690         }
1691         switch (opcode) {
1692         case OP(RDMA_READ_REQUEST): {
1693                 struct ib_reth *reth;
1694                 u32 offset;
1695                 u32 len;
1696
1697                 /*
1698                  * If we didn't find the RDMA read request in the ack queue,
1699                  * we can ignore this request.
1700                  */
1701                 if (!e || e->opcode != OP(RDMA_READ_REQUEST))
1702                         goto unlock_done;
1703                 /* RETH comes after BTH */
1704                 reth = &ohdr->u.rc.reth;
1705                 /*
1706                  * Address range must be a subset of the original
1707                  * request and start on pmtu boundaries.
1708                  * We reuse the old ack_queue slot since the requester
1709                  * should not back up and request an earlier PSN for the
1710                  * same request.
1711                  */
1712                 offset = ((psn - e->psn) & QIB_PSN_MASK) *
1713                         ib_mtu_enum_to_int(qp->path_mtu);
1714                 len = be32_to_cpu(reth->length);
1715                 if (unlikely(offset + len != e->rdma_sge.sge_length))
1716                         goto unlock_done;
1717                 if (e->rdma_sge.mr) {
1718                         atomic_dec(&e->rdma_sge.mr->refcount);
1719                         e->rdma_sge.mr = NULL;
1720                 }
1721                 if (len != 0) {
1722                         u32 rkey = be32_to_cpu(reth->rkey);
1723                         u64 vaddr = be64_to_cpu(reth->vaddr);
1724                         int ok;
1725
1726                         ok = qib_rkey_ok(qp, &e->rdma_sge, len, vaddr, rkey,
1727                                          IB_ACCESS_REMOTE_READ);
1728                         if (unlikely(!ok))
1729                                 goto unlock_done;
1730                 } else {
1731                         e->rdma_sge.vaddr = NULL;
1732                         e->rdma_sge.length = 0;
1733                         e->rdma_sge.sge_length = 0;
1734                 }
1735                 e->psn = psn;
1736                 if (old_req)
1737                         goto unlock_done;
1738                 qp->s_tail_ack_queue = prev;
1739                 break;
1740         }
1741
1742         case OP(COMPARE_SWAP):
1743         case OP(FETCH_ADD): {
1744                 /*
1745                  * If we didn't find the atomic request in the ack queue
1746                  * or the send tasklet is already backed up to send an
1747                  * earlier entry, we can ignore this request.
1748                  */
1749                 if (!e || e->opcode != (u8) opcode || old_req)
1750                         goto unlock_done;
1751                 qp->s_tail_ack_queue = prev;
1752                 break;
1753         }
1754
1755         default:
1756                 /*
1757                  * Ignore this operation if it doesn't request an ACK
1758                  * or an earlier RDMA read or atomic is going to be resent.
1759                  */
1760                 if (!(psn & IB_BTH_REQ_ACK) || old_req)
1761                         goto unlock_done;
1762                 /*
1763                  * Resend the most recent ACK if this request is
1764                  * after all the previous RDMA reads and atomics.
1765                  */
1766                 if (i == qp->r_head_ack_queue) {
1767                         spin_unlock_irqrestore(&qp->s_lock, flags);
1768                         qp->r_nak_state = 0;
1769                         qp->r_ack_psn = qp->r_psn - 1;
1770                         goto send_ack;
1771                 }
1772                 /*
1773                  * Try to send a simple ACK to work around a Mellanox bug
1774                  * which doesn't accept a RDMA read response or atomic
1775                  * response as an ACK for earlier SENDs or RDMA writes.
1776                  */
1777                 if (!(qp->s_flags & QIB_S_RESP_PENDING)) {
1778                         spin_unlock_irqrestore(&qp->s_lock, flags);
1779                         qp->r_nak_state = 0;
1780                         qp->r_ack_psn = qp->s_ack_queue[i].psn - 1;
1781                         goto send_ack;
1782                 }
1783                 /*
1784                  * Resend the RDMA read or atomic op which
1785                  * ACKs this duplicate request.
1786                  */
1787                 qp->s_tail_ack_queue = i;
1788                 break;
1789         }
1790         qp->s_ack_state = OP(ACKNOWLEDGE);
1791         qp->s_flags |= QIB_S_RESP_PENDING;
1792         qp->r_nak_state = 0;
1793         qib_schedule_send(qp);
1794
1795 unlock_done:
1796         spin_unlock_irqrestore(&qp->s_lock, flags);
1797 done:
1798         return 1;
1799
1800 send_ack:
1801         return 0;
1802 }
1803
1804 void qib_rc_error(struct qib_qp *qp, enum ib_wc_status err)
1805 {
1806         unsigned long flags;
1807         int lastwqe;
1808
1809         spin_lock_irqsave(&qp->s_lock, flags);
1810         lastwqe = qib_error_qp(qp, err);
1811         spin_unlock_irqrestore(&qp->s_lock, flags);
1812
1813         if (lastwqe) {
1814                 struct ib_event ev;
1815
1816                 ev.device = qp->ibqp.device;
1817                 ev.element.qp = &qp->ibqp;
1818                 ev.event = IB_EVENT_QP_LAST_WQE_REACHED;
1819                 qp->ibqp.event_handler(&ev, qp->ibqp.qp_context);
1820         }
1821 }
1822
1823 static inline void qib_update_ack_queue(struct qib_qp *qp, unsigned n)
1824 {
1825         unsigned next;
1826
1827         next = n + 1;
1828         if (next > QIB_MAX_RDMA_ATOMIC)
1829                 next = 0;
1830         qp->s_tail_ack_queue = next;
1831         qp->s_ack_state = OP(ACKNOWLEDGE);
1832 }
1833
1834 /**
1835  * qib_rc_rcv - process an incoming RC packet
1836  * @rcd: the context pointer
1837  * @hdr: the header of this packet
1838  * @has_grh: true if the header has a GRH
1839  * @data: the packet data
1840  * @tlen: the packet length
1841  * @qp: the QP for this packet
1842  *
1843  * This is called from qib_qp_rcv() to process an incoming RC packet
1844  * for the given QP.
1845  * Called at interrupt level.
1846  */
1847 void qib_rc_rcv(struct qib_ctxtdata *rcd, struct qib_ib_header *hdr,
1848                 int has_grh, void *data, u32 tlen, struct qib_qp *qp)
1849 {
1850         struct qib_ibport *ibp = &rcd->ppd->ibport_data;
1851         struct qib_other_headers *ohdr;
1852         u32 opcode;
1853         u32 hdrsize;
1854         u32 psn;
1855         u32 pad;
1856         struct ib_wc wc;
1857         u32 pmtu = ib_mtu_enum_to_int(qp->path_mtu);
1858         int diff;
1859         struct ib_reth *reth;
1860         unsigned long flags;
1861         int ret;
1862
1863         /* Check for GRH */
1864         if (!has_grh) {
1865                 ohdr = &hdr->u.oth;
1866                 hdrsize = 8 + 12;       /* LRH + BTH */
1867         } else {
1868                 ohdr = &hdr->u.l.oth;
1869                 hdrsize = 8 + 40 + 12;  /* LRH + GRH + BTH */
1870         }
1871
1872         opcode = be32_to_cpu(ohdr->bth[0]);
1873         spin_lock_irqsave(&qp->s_lock, flags);
1874         if (qib_ruc_check_hdr(ibp, hdr, has_grh, qp, opcode))
1875                 goto sunlock;
1876         spin_unlock_irqrestore(&qp->s_lock, flags);
1877
1878         psn = be32_to_cpu(ohdr->bth[2]);
1879         opcode >>= 24;
1880
1881         /* Prevent simultaneous processing after APM on different CPUs */
1882         spin_lock(&qp->r_lock);
1883
1884         /*
1885          * Process responses (ACKs) before anything else.  Note that the
1886          * packet sequence number will be for something in the send work
1887          * queue rather than the expected receive packet sequence number.
1888          * In other words, this QP is the requester.
1889          */
1890         if (opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
1891             opcode <= OP(ATOMIC_ACKNOWLEDGE)) {
1892                 qib_rc_rcv_resp(ibp, ohdr, data, tlen, qp, opcode, psn,
1893                                 hdrsize, pmtu, rcd);
1894                 goto runlock;
1895         }
1896
1897         /* Compute 24 bits worth of difference. */
1898         diff = qib_cmp24(psn, qp->r_psn);
1899         if (unlikely(diff)) {
1900                 if (qib_rc_rcv_error(ohdr, data, qp, opcode, psn, diff, rcd))
1901                         goto runlock;
1902                 goto send_ack;
1903         }
1904
1905         /* Check for opcode sequence errors. */
1906         switch (qp->r_state) {
1907         case OP(SEND_FIRST):
1908         case OP(SEND_MIDDLE):
1909                 if (opcode == OP(SEND_MIDDLE) ||
1910                     opcode == OP(SEND_LAST) ||
1911                     opcode == OP(SEND_LAST_WITH_IMMEDIATE))
1912                         break;
1913                 goto nack_inv;
1914
1915         case OP(RDMA_WRITE_FIRST):
1916         case OP(RDMA_WRITE_MIDDLE):
1917                 if (opcode == OP(RDMA_WRITE_MIDDLE) ||
1918                     opcode == OP(RDMA_WRITE_LAST) ||
1919                     opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
1920                         break;
1921                 goto nack_inv;
1922
1923         default:
1924                 if (opcode == OP(SEND_MIDDLE) ||
1925                     opcode == OP(SEND_LAST) ||
1926                     opcode == OP(SEND_LAST_WITH_IMMEDIATE) ||
1927                     opcode == OP(RDMA_WRITE_MIDDLE) ||
1928                     opcode == OP(RDMA_WRITE_LAST) ||
1929                     opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
1930                         goto nack_inv;
1931                 /*
1932                  * Note that it is up to the requester to not send a new
1933                  * RDMA read or atomic operation before receiving an ACK
1934                  * for the previous operation.
1935                  */
1936                 break;
1937         }
1938
1939         memset(&wc, 0, sizeof wc);
1940
1941         if (qp->state == IB_QPS_RTR && !(qp->r_flags & QIB_R_COMM_EST)) {
1942                 qp->r_flags |= QIB_R_COMM_EST;
1943                 if (qp->ibqp.event_handler) {
1944                         struct ib_event ev;
1945
1946                         ev.device = qp->ibqp.device;
1947                         ev.element.qp = &qp->ibqp;
1948                         ev.event = IB_EVENT_COMM_EST;
1949                         qp->ibqp.event_handler(&ev, qp->ibqp.qp_context);
1950                 }
1951         }
1952
1953         /* OK, process the packet. */
1954         switch (opcode) {
1955         case OP(SEND_FIRST):
1956                 ret = qib_get_rwqe(qp, 0);
1957                 if (ret < 0)
1958                         goto nack_op_err;
1959                 if (!ret)
1960                         goto rnr_nak;
1961                 qp->r_rcv_len = 0;
1962                 /* FALLTHROUGH */
1963         case OP(SEND_MIDDLE):
1964         case OP(RDMA_WRITE_MIDDLE):
1965 send_middle:
1966                 /* Check for invalid length PMTU or posted rwqe len. */
1967                 if (unlikely(tlen != (hdrsize + pmtu + 4)))
1968                         goto nack_inv;
1969                 qp->r_rcv_len += pmtu;
1970                 if (unlikely(qp->r_rcv_len > qp->r_len))
1971                         goto nack_inv;
1972                 qib_copy_sge(&qp->r_sge, data, pmtu, 1);
1973                 break;
1974
1975         case OP(RDMA_WRITE_LAST_WITH_IMMEDIATE):
1976                 /* consume RWQE */
1977                 ret = qib_get_rwqe(qp, 1);
1978                 if (ret < 0)
1979                         goto nack_op_err;
1980                 if (!ret)
1981                         goto rnr_nak;
1982                 goto send_last_imm;
1983
1984         case OP(SEND_ONLY):
1985         case OP(SEND_ONLY_WITH_IMMEDIATE):
1986                 ret = qib_get_rwqe(qp, 0);
1987                 if (ret < 0)
1988                         goto nack_op_err;
1989                 if (!ret)
1990                         goto rnr_nak;
1991                 qp->r_rcv_len = 0;
1992                 if (opcode == OP(SEND_ONLY))
1993                         goto send_last;
1994                 /* FALLTHROUGH */
1995         case OP(SEND_LAST_WITH_IMMEDIATE):
1996 send_last_imm:
1997                 wc.ex.imm_data = ohdr->u.imm_data;
1998                 hdrsize += 4;
1999                 wc.wc_flags = IB_WC_WITH_IMM;
2000                 /* FALLTHROUGH */
2001         case OP(SEND_LAST):
2002         case OP(RDMA_WRITE_LAST):
2003 send_last:
2004                 /* Get the number of bytes the message was padded by. */
2005                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
2006                 /* Check for invalid length. */
2007                 /* XXX LAST len should be >= 1 */
2008                 if (unlikely(tlen < (hdrsize + pad + 4)))
2009                         goto nack_inv;
2010                 /* Don't count the CRC. */
2011                 tlen -= (hdrsize + pad + 4);
2012                 wc.byte_len = tlen + qp->r_rcv_len;
2013                 if (unlikely(wc.byte_len > qp->r_len))
2014                         goto nack_inv;
2015                 qib_copy_sge(&qp->r_sge, data, tlen, 1);
2016                 while (qp->r_sge.num_sge) {
2017                         atomic_dec(&qp->r_sge.sge.mr->refcount);
2018                         if (--qp->r_sge.num_sge)
2019                                 qp->r_sge.sge = *qp->r_sge.sg_list++;
2020                 }
2021                 qp->r_msn++;
2022                 if (!test_and_clear_bit(QIB_R_WRID_VALID, &qp->r_aflags))
2023                         break;
2024                 wc.wr_id = qp->r_wr_id;
2025                 wc.status = IB_WC_SUCCESS;
2026                 if (opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE) ||
2027                     opcode == OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE))
2028                         wc.opcode = IB_WC_RECV_RDMA_WITH_IMM;
2029                 else
2030                         wc.opcode = IB_WC_RECV;
2031                 wc.qp = &qp->ibqp;
2032                 wc.src_qp = qp->remote_qpn;
2033                 wc.slid = qp->remote_ah_attr.dlid;
2034                 wc.sl = qp->remote_ah_attr.sl;
2035                 /* Signal completion event if the solicited bit is set. */
2036                 qib_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
2037                              (ohdr->bth[0] &
2038                               cpu_to_be32(IB_BTH_SOLICITED)) != 0);
2039                 break;
2040
2041         case OP(RDMA_WRITE_FIRST):
2042         case OP(RDMA_WRITE_ONLY):
2043         case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE):
2044                 if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_WRITE)))
2045                         goto nack_inv;
2046                 /* consume RWQE */
2047                 reth = &ohdr->u.rc.reth;
2048                 hdrsize += sizeof(*reth);
2049                 qp->r_len = be32_to_cpu(reth->length);
2050                 qp->r_rcv_len = 0;
2051                 qp->r_sge.sg_list = NULL;
2052                 if (qp->r_len != 0) {
2053                         u32 rkey = be32_to_cpu(reth->rkey);
2054                         u64 vaddr = be64_to_cpu(reth->vaddr);
2055                         int ok;
2056
2057                         /* Check rkey & NAK */
2058                         ok = qib_rkey_ok(qp, &qp->r_sge.sge, qp->r_len, vaddr,
2059                                          rkey, IB_ACCESS_REMOTE_WRITE);
2060                         if (unlikely(!ok))
2061                                 goto nack_acc;
2062                         qp->r_sge.num_sge = 1;
2063                 } else {
2064                         qp->r_sge.num_sge = 0;
2065                         qp->r_sge.sge.mr = NULL;
2066                         qp->r_sge.sge.vaddr = NULL;
2067                         qp->r_sge.sge.length = 0;
2068                         qp->r_sge.sge.sge_length = 0;
2069                 }
2070                 if (opcode == OP(RDMA_WRITE_FIRST))
2071                         goto send_middle;
2072                 else if (opcode == OP(RDMA_WRITE_ONLY))
2073                         goto send_last;
2074                 ret = qib_get_rwqe(qp, 1);
2075                 if (ret < 0)
2076                         goto nack_op_err;
2077                 if (!ret)
2078                         goto rnr_nak;
2079                 goto send_last_imm;
2080
2081         case OP(RDMA_READ_REQUEST): {
2082                 struct qib_ack_entry *e;
2083                 u32 len;
2084                 u8 next;
2085
2086                 if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_READ)))
2087                         goto nack_inv;
2088                 next = qp->r_head_ack_queue + 1;
2089                 /* s_ack_queue is size QIB_MAX_RDMA_ATOMIC+1 so use > not >= */
2090                 if (next > QIB_MAX_RDMA_ATOMIC)
2091                         next = 0;
2092                 spin_lock_irqsave(&qp->s_lock, flags);
2093                 /* Double check we can process this while holding the s_lock. */
2094                 if (!(ib_qib_state_ops[qp->state] & QIB_PROCESS_RECV_OK))
2095                         goto srunlock;
2096                 if (unlikely(next == qp->s_tail_ack_queue)) {
2097                         if (!qp->s_ack_queue[next].sent)
2098                                 goto nack_inv_unlck;
2099                         qib_update_ack_queue(qp, next);
2100                 }
2101                 e = &qp->s_ack_queue[qp->r_head_ack_queue];
2102                 if (e->opcode == OP(RDMA_READ_REQUEST) && e->rdma_sge.mr) {
2103                         atomic_dec(&e->rdma_sge.mr->refcount);
2104                         e->rdma_sge.mr = NULL;
2105                 }
2106                 reth = &ohdr->u.rc.reth;
2107                 len = be32_to_cpu(reth->length);
2108                 if (len) {
2109                         u32 rkey = be32_to_cpu(reth->rkey);
2110                         u64 vaddr = be64_to_cpu(reth->vaddr);
2111                         int ok;
2112
2113                         /* Check rkey & NAK */
2114                         ok = qib_rkey_ok(qp, &e->rdma_sge, len, vaddr,
2115                                          rkey, IB_ACCESS_REMOTE_READ);
2116                         if (unlikely(!ok))
2117                                 goto nack_acc_unlck;
2118                         /*
2119                          * Update the next expected PSN.  We add 1 later
2120                          * below, so only add the remainder here.
2121                          */
2122                         if (len > pmtu)
2123                                 qp->r_psn += (len - 1) / pmtu;
2124                 } else {
2125                         e->rdma_sge.mr = NULL;
2126                         e->rdma_sge.vaddr = NULL;
2127                         e->rdma_sge.length = 0;
2128                         e->rdma_sge.sge_length = 0;
2129                 }
2130                 e->opcode = opcode;
2131                 e->sent = 0;
2132                 e->psn = psn;
2133                 e->lpsn = qp->r_psn;
2134                 /*
2135                  * We need to increment the MSN here instead of when we
2136                  * finish sending the result since a duplicate request would
2137                  * increment it more than once.
2138                  */
2139                 qp->r_msn++;
2140                 qp->r_psn++;
2141                 qp->r_state = opcode;
2142                 qp->r_nak_state = 0;
2143                 qp->r_head_ack_queue = next;
2144
2145                 /* Schedule the send tasklet. */
2146                 qp->s_flags |= QIB_S_RESP_PENDING;
2147                 qib_schedule_send(qp);
2148
2149                 goto srunlock;
2150         }
2151
2152         case OP(COMPARE_SWAP):
2153         case OP(FETCH_ADD): {
2154                 struct ib_atomic_eth *ateth;
2155                 struct qib_ack_entry *e;
2156                 u64 vaddr;
2157                 atomic64_t *maddr;
2158                 u64 sdata;
2159                 u32 rkey;
2160                 u8 next;
2161
2162                 if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_ATOMIC)))
2163                         goto nack_inv;
2164                 next = qp->r_head_ack_queue + 1;
2165                 if (next > QIB_MAX_RDMA_ATOMIC)
2166                         next = 0;
2167                 spin_lock_irqsave(&qp->s_lock, flags);
2168                 /* Double check we can process this while holding the s_lock. */
2169                 if (!(ib_qib_state_ops[qp->state] & QIB_PROCESS_RECV_OK))
2170                         goto srunlock;
2171                 if (unlikely(next == qp->s_tail_ack_queue)) {
2172                         if (!qp->s_ack_queue[next].sent)
2173                                 goto nack_inv_unlck;
2174                         qib_update_ack_queue(qp, next);
2175                 }
2176                 e = &qp->s_ack_queue[qp->r_head_ack_queue];
2177                 if (e->opcode == OP(RDMA_READ_REQUEST) && e->rdma_sge.mr) {
2178                         atomic_dec(&e->rdma_sge.mr->refcount);
2179                         e->rdma_sge.mr = NULL;
2180                 }
2181                 ateth = &ohdr->u.atomic_eth;
2182                 vaddr = ((u64) be32_to_cpu(ateth->vaddr[0]) << 32) |
2183                         be32_to_cpu(ateth->vaddr[1]);
2184                 if (unlikely(vaddr & (sizeof(u64) - 1)))
2185                         goto nack_inv_unlck;
2186                 rkey = be32_to_cpu(ateth->rkey);
2187                 /* Check rkey & NAK */
2188                 if (unlikely(!qib_rkey_ok(qp, &qp->r_sge.sge, sizeof(u64),
2189                                           vaddr, rkey,
2190                                           IB_ACCESS_REMOTE_ATOMIC)))
2191                         goto nack_acc_unlck;
2192                 /* Perform atomic OP and save result. */
2193                 maddr = (atomic64_t *) qp->r_sge.sge.vaddr;
2194                 sdata = be64_to_cpu(ateth->swap_data);
2195                 e->atomic_data = (opcode == OP(FETCH_ADD)) ?
2196                         (u64) atomic64_add_return(sdata, maddr) - sdata :
2197                         (u64) cmpxchg((u64 *) qp->r_sge.sge.vaddr,
2198                                       be64_to_cpu(ateth->compare_data),
2199                                       sdata);
2200                 atomic_dec(&qp->r_sge.sge.mr->refcount);
2201                 qp->r_sge.num_sge = 0;
2202                 e->opcode = opcode;
2203                 e->sent = 0;
2204                 e->psn = psn;
2205                 e->lpsn = psn;
2206                 qp->r_msn++;
2207                 qp->r_psn++;
2208                 qp->r_state = opcode;
2209                 qp->r_nak_state = 0;
2210                 qp->r_head_ack_queue = next;
2211
2212                 /* Schedule the send tasklet. */
2213                 qp->s_flags |= QIB_S_RESP_PENDING;
2214                 qib_schedule_send(qp);
2215
2216                 goto srunlock;
2217         }
2218
2219         default:
2220                 /* NAK unknown opcodes. */
2221                 goto nack_inv;
2222         }
2223         qp->r_psn++;
2224         qp->r_state = opcode;
2225         qp->r_ack_psn = psn;
2226         qp->r_nak_state = 0;
2227         /* Send an ACK if requested or required. */
2228         if (psn & (1 << 31))
2229                 goto send_ack;
2230         goto runlock;
2231
2232 rnr_nak:
2233         qp->r_nak_state = IB_RNR_NAK | qp->r_min_rnr_timer;
2234         qp->r_ack_psn = qp->r_psn;
2235         /* Queue RNR NAK for later */
2236         if (list_empty(&qp->rspwait)) {
2237                 qp->r_flags |= QIB_R_RSP_NAK;
2238                 atomic_inc(&qp->refcount);
2239                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
2240         }
2241         goto runlock;
2242
2243 nack_op_err:
2244         qib_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
2245         qp->r_nak_state = IB_NAK_REMOTE_OPERATIONAL_ERROR;
2246         qp->r_ack_psn = qp->r_psn;
2247         /* Queue NAK for later */
2248         if (list_empty(&qp->rspwait)) {
2249                 qp->r_flags |= QIB_R_RSP_NAK;
2250                 atomic_inc(&qp->refcount);
2251                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
2252         }
2253         goto runlock;
2254
2255 nack_inv_unlck:
2256         spin_unlock_irqrestore(&qp->s_lock, flags);
2257 nack_inv:
2258         qib_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
2259         qp->r_nak_state = IB_NAK_INVALID_REQUEST;
2260         qp->r_ack_psn = qp->r_psn;
2261         /* Queue NAK for later */
2262         if (list_empty(&qp->rspwait)) {
2263                 qp->r_flags |= QIB_R_RSP_NAK;
2264                 atomic_inc(&qp->refcount);
2265                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
2266         }
2267         goto runlock;
2268
2269 nack_acc_unlck:
2270         spin_unlock_irqrestore(&qp->s_lock, flags);
2271 nack_acc:
2272         qib_rc_error(qp, IB_WC_LOC_PROT_ERR);
2273         qp->r_nak_state = IB_NAK_REMOTE_ACCESS_ERROR;
2274         qp->r_ack_psn = qp->r_psn;
2275 send_ack:
2276         qib_send_rc_ack(qp);
2277 runlock:
2278         spin_unlock(&qp->r_lock);
2279         return;
2280
2281 srunlock:
2282         spin_unlock_irqrestore(&qp->s_lock, flags);
2283         spin_unlock(&qp->r_lock);
2284         return;
2285
2286 sunlock:
2287         spin_unlock_irqrestore(&qp->s_lock, flags);
2288 }