release/src-rt-6.x.4708/linux/linux-2.6.36/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 r_lock and 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
 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->r_lock, flags);
 915         spin_lock(&qp->s_lock);
 916         if (qp->s_flags & QIB_S_TIMER) {
 917                 ibp = to_iport(qp->ibqp.device, qp->port_num);
 918                 ibp->n_rc_timeouts++;
 919                 qp->s_flags &= ~QIB_S_TIMER;
 920                 del_timer(&qp->s_timer);
 921                 qib_restart_rc(qp, qp->s_last_psn + 1, 1);
 922                 qib_schedule_send(qp);
 923         }
 924         spin_unlock(&qp->s_lock);
 925         spin_unlock_irqrestore(&qp->r_lock, flags);
 926 }
 927
 928 /*
 929  * This is called from s_timer for RNR timeouts.
 930  */
 931 void qib_rc_rnr_retry(unsigned long arg)
 932 {
 933         struct qib_qp *qp = (struct qib_qp *)arg;
 934         unsigned long flags;
 935
 936         spin_lock_irqsave(&qp->s_lock, flags);
 937         if (qp->s_flags & QIB_S_WAIT_RNR) {
 938                 qp->s_flags &= ~QIB_S_WAIT_RNR;
 939                 del_timer(&qp->s_timer);
 940                 qib_schedule_send(qp);
 941         }
 942         spin_unlock_irqrestore(&qp->s_lock, flags);
 943 }
 944
 945 /*
 946  * Set qp->s_sending_psn to the next PSN after the given one.
 947  * This would be psn+1 except when RDMA reads are present.
 948  */
 949 static void reset_sending_psn(struct qib_qp *qp, u32 psn)
 950 {
 951         struct qib_swqe *wqe;
 952         u32 n = qp->s_last;
 953
 954         /* Find the work request corresponding to the given PSN. */
 955         for (;;) {
 956                 wqe = get_swqe_ptr(qp, n);
 957                 if (qib_cmp24(psn, wqe->lpsn) <= 0) {
 958                         if (wqe->wr.opcode == IB_WR_RDMA_READ)
 959                                 qp->s_sending_psn = wqe->lpsn + 1;
 960                         else
 961                                 qp->s_sending_psn = psn + 1;
 962                         break;
 963                 }
 964                 if (++n == qp->s_size)
 965                         n = 0;
 966                 if (n == qp->s_tail)
 967                         break;
 968         }
 969 }
 970
 971 /*
 972  * This should be called with the QP s_lock held and interrupts disabled.
 973  */
 974 void qib_rc_send_complete(struct qib_qp *qp, struct qib_ib_header *hdr)
 975 {
 976         struct qib_other_headers *ohdr;
 977         struct qib_swqe *wqe;
 978         struct ib_wc wc;
 979         unsigned i;
 980         u32 opcode;
 981         u32 psn;
 982
 983         if (!(ib_qib_state_ops[qp->state] & QIB_PROCESS_OR_FLUSH_SEND))
 984                 return;
 985
 986         /* Find out where the BTH is */
 987         if ((be16_to_cpu(hdr->lrh[0]) & 3) == QIB_LRH_BTH)
 988                 ohdr = &hdr->u.oth;
 989         else
 990                 ohdr = &hdr->u.l.oth;
 991
 992         opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
 993         if (opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
 994             opcode <= OP(ATOMIC_ACKNOWLEDGE)) {
 995                 WARN_ON(!qp->s_rdma_ack_cnt);
 996                 qp->s_rdma_ack_cnt--;
 997                 return;
 998         }
 999
1000         psn = be32_to_cpu(ohdr->bth[2]);
1001         reset_sending_psn(qp, psn);
1002
1003         /*
1004          * Start timer after a packet requesting an ACK has been sent and
1005          * there are still requests that haven't been acked.
1006          */
1007         if ((psn & IB_BTH_REQ_ACK) && qp->s_acked != qp->s_tail &&
1008             !(qp->s_flags & (QIB_S_TIMER | QIB_S_WAIT_RNR | QIB_S_WAIT_PSN)))
1009                 start_timer(qp);
1010
1011         while (qp->s_last != qp->s_acked) {
1012                 wqe = get_swqe_ptr(qp, qp->s_last);
1013                 if (qib_cmp24(wqe->lpsn, qp->s_sending_psn) >= 0 &&
1014                     qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) <= 0)
1015                         break;
1016                 for (i = 0; i < wqe->wr.num_sge; i++) {
1017                         struct qib_sge *sge = &wqe->sg_list[i];
1018
1019                         atomic_dec(&sge->mr->refcount);
1020                 }
1021                 /* Post a send completion queue entry if requested. */
1022                 if (!(qp->s_flags & QIB_S_SIGNAL_REQ_WR) ||
1023                     (wqe->wr.send_flags & IB_SEND_SIGNALED)) {
1024                         memset(&wc, 0, sizeof wc);
1025                         wc.wr_id = wqe->wr.wr_id;
1026                         wc.status = IB_WC_SUCCESS;
1027                         wc.opcode = ib_qib_wc_opcode[wqe->wr.opcode];
1028                         wc.byte_len = wqe->length;
1029                         wc.qp = &qp->ibqp;
1030                         qib_cq_enter(to_icq(qp->ibqp.send_cq), &wc, 0);
1031                 }
1032                 if (++qp->s_last >= qp->s_size)
1033                         qp->s_last = 0;
1034         }
1035         /*
1036          * If we were waiting for sends to complete before resending,
1037          * and they are now complete, restart sending.
1038          */
1039         if (qp->s_flags & QIB_S_WAIT_PSN &&
1040             qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) > 0) {
1041                 qp->s_flags &= ~QIB_S_WAIT_PSN;
1042                 qp->s_sending_psn = qp->s_psn;
1043                 qp->s_sending_hpsn = qp->s_psn - 1;
1044                 qib_schedule_send(qp);
1045         }
1046 }
1047
1048 static inline void update_last_psn(struct qib_qp *qp, u32 psn)
1049 {
1050         qp->s_last_psn = psn;
1051 }
1052
1053 /*
1054  * Generate a SWQE completion.
1055  * This is similar to qib_send_complete but has to check to be sure
1056  * that the SGEs are not being referenced if the SWQE is being resent.
1057  */
1058 static struct qib_swqe *do_rc_completion(struct qib_qp *qp,
1059                                          struct qib_swqe *wqe,
1060                                          struct qib_ibport *ibp)
1061 {
1062         struct ib_wc wc;
1063         unsigned i;
1064
1065         /*
1066          * Don't decrement refcount and don't generate a
1067          * completion if the SWQE is being resent until the send
1068          * is finished.
1069          */
1070         if (qib_cmp24(wqe->lpsn, qp->s_sending_psn) < 0 ||
1071             qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) > 0) {
1072                 for (i = 0; i < wqe->wr.num_sge; i++) {
1073                         struct qib_sge *sge = &wqe->sg_list[i];
1074
1075                         atomic_dec(&sge->mr->refcount);
1076                 }
1077                 /* Post a send completion queue entry if requested. */
1078                 if (!(qp->s_flags & QIB_S_SIGNAL_REQ_WR) ||
1079                     (wqe->wr.send_flags & IB_SEND_SIGNALED)) {
1080                         memset(&wc, 0, sizeof wc);
1081                         wc.wr_id = wqe->wr.wr_id;
1082                         wc.status = IB_WC_SUCCESS;
1083                         wc.opcode = ib_qib_wc_opcode[wqe->wr.opcode];
1084                         wc.byte_len = wqe->length;
1085                         wc.qp = &qp->ibqp;
1086                         qib_cq_enter(to_icq(qp->ibqp.send_cq), &wc, 0);
1087                 }
1088                 if (++qp->s_last >= qp->s_size)
1089                         qp->s_last = 0;
1090         } else
1091                 ibp->n_rc_delayed_comp++;
1092
1093         qp->s_retry = qp->s_retry_cnt;
1094         update_last_psn(qp, wqe->lpsn);
1095
1096         /*
1097          * If we are completing a request which is in the process of
1098          * being resent, we can stop resending it since we know the
1099          * responder has already seen it.
1100          */
1101         if (qp->s_acked == qp->s_cur) {
1102                 if (++qp->s_cur >= qp->s_size)
1103                         qp->s_cur = 0;
1104                 qp->s_acked = qp->s_cur;
1105                 wqe = get_swqe_ptr(qp, qp->s_cur);
1106                 if (qp->s_acked != qp->s_tail) {
1107                         qp->s_state = OP(SEND_LAST);
1108                         qp->s_psn = wqe->psn;
1109                 }
1110         } else {
1111                 if (++qp->s_acked >= qp->s_size)
1112                         qp->s_acked = 0;
1113                 if (qp->state == IB_QPS_SQD && qp->s_acked == qp->s_cur)
1114                         qp->s_draining = 0;
1115                 wqe = get_swqe_ptr(qp, qp->s_acked);
1116         }
1117         return wqe;
1118 }
1119
1120 /**
1121  * do_rc_ack - process an incoming RC ACK
1122  * @qp: the QP the ACK came in on
1123  * @psn: the packet sequence number of the ACK
1124  * @opcode: the opcode of the request that resulted in the ACK
1125  *
1126  * This is called from qib_rc_rcv_resp() to process an incoming RC ACK
1127  * for the given QP.
1128  * Called at interrupt level with the QP s_lock held.
1129  * Returns 1 if OK, 0 if current operation should be aborted (NAK).
1130  */
1131 static int do_rc_ack(struct qib_qp *qp, u32 aeth, u32 psn, int opcode,
1132                      u64 val, struct qib_ctxtdata *rcd)
1133 {
1134         struct qib_ibport *ibp;
1135         enum ib_wc_status status;
1136         struct qib_swqe *wqe;
1137         int ret = 0;
1138         u32 ack_psn;
1139         int diff;
1140
1141         /* Remove QP from retry timer */
1142         if (qp->s_flags & (QIB_S_TIMER | QIB_S_WAIT_RNR)) {
1143                 qp->s_flags &= ~(QIB_S_TIMER | QIB_S_WAIT_RNR);
1144                 del_timer(&qp->s_timer);
1145         }
1146
1147         /*
1148          * Note that NAKs implicitly ACK outstanding SEND and RDMA write
1149          * requests and implicitly NAK RDMA read and atomic requests issued
1150          * before the NAK'ed request.  The MSN won't include the NAK'ed
1151          * request but will include an ACK'ed request(s).
1152          */
1153         ack_psn = psn;
1154         if (aeth >> 29)
1155                 ack_psn--;
1156         wqe = get_swqe_ptr(qp, qp->s_acked);
1157         ibp = to_iport(qp->ibqp.device, qp->port_num);
1158
1159         /*
1160          * The MSN might be for a later WQE than the PSN indicates so
1161          * only complete WQEs that the PSN finishes.
1162          */
1163         while ((diff = qib_cmp24(ack_psn, wqe->lpsn)) >= 0) {
1164                 /*
1165                  * RDMA_READ_RESPONSE_ONLY is a special case since
1166                  * we want to generate completion events for everything
1167                  * before the RDMA read, copy the data, then generate
1168                  * the completion for the read.
1169                  */
1170                 if (wqe->wr.opcode == IB_WR_RDMA_READ &&
1171                     opcode == OP(RDMA_READ_RESPONSE_ONLY) &&
1172                     diff == 0) {
1173                         ret = 1;
1174                         goto bail;
1175                 }
1176                 /*
1177                  * If this request is a RDMA read or atomic, and the ACK is
1178                  * for a later operation, this ACK NAKs the RDMA read or
1179                  * atomic.  In other words, only a RDMA_READ_LAST or ONLY
1180                  * can ACK a RDMA read and likewise for atomic ops.  Note
1181                  * that the NAK case can only happen if relaxed ordering is
1182                  * used and requests are sent after an RDMA read or atomic
1183                  * is sent but before the response is received.
1184                  */
1185                 if ((wqe->wr.opcode == IB_WR_RDMA_READ &&
1186                      (opcode != OP(RDMA_READ_RESPONSE_LAST) || diff != 0)) ||
1187                     ((wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1188                       wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) &&
1189                      (opcode != OP(ATOMIC_ACKNOWLEDGE) || diff != 0))) {
1190                         /* Retry this request. */
1191                         if (!(qp->r_flags & QIB_R_RDMAR_SEQ)) {
1192                                 qp->r_flags |= QIB_R_RDMAR_SEQ;
1193                                 qib_restart_rc(qp, qp->s_last_psn + 1, 0);
1194                                 if (list_empty(&qp->rspwait)) {
1195                                         qp->r_flags |= QIB_R_RSP_SEND;
1196                                         atomic_inc(&qp->refcount);
1197                                         list_add_tail(&qp->rspwait,
1198                                                       &rcd->qp_wait_list);
1199                                 }
1200                         }
1201                         /*
1202                          * No need to process the ACK/NAK since we are
1203                          * restarting an earlier request.
1204                          */
1205                         goto bail;
1206                 }
1207                 if (wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1208                     wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) {
1209                         u64 *vaddr = wqe->sg_list[0].vaddr;
1210                         *vaddr = val;
1211                 }
1212                 if (qp->s_num_rd_atomic &&
1213                     (wqe->wr.opcode == IB_WR_RDMA_READ ||
1214                      wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1215                      wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)) {
1216                         qp->s_num_rd_atomic--;
1217                         /* Restart sending task if fence is complete */
1218                         if ((qp->s_flags & QIB_S_WAIT_FENCE) &&
1219                             !qp->s_num_rd_atomic) {
1220                                 qp->s_flags &= ~(QIB_S_WAIT_FENCE |
1221                                                  QIB_S_WAIT_ACK);
1222                                 qib_schedule_send(qp);
1223                         } else if (qp->s_flags & QIB_S_WAIT_RDMAR) {
1224                                 qp->s_flags &= ~(QIB_S_WAIT_RDMAR |
1225                                                  QIB_S_WAIT_ACK);
1226                                 qib_schedule_send(qp);
1227                         }
1228                 }
1229                 wqe = do_rc_completion(qp, wqe, ibp);
1230                 if (qp->s_acked == qp->s_tail)
1231                         break;
1232         }
1233
1234         switch (aeth >> 29) {
1235         case 0:         /* ACK */
1236                 ibp->n_rc_acks++;
1237                 if (qp->s_acked != qp->s_tail) {
1238                         /*
1239                          * We are expecting more ACKs so
1240                          * reset the retransmit timer.
1241                          */
1242                         start_timer(qp);
1243                         /*
1244                          * We can stop resending the earlier packets and
1245                          * continue with the next packet the receiver wants.
1246                          */
1247                         if (qib_cmp24(qp->s_psn, psn) <= 0)
1248                                 reset_psn(qp, psn + 1);
1249                 } else if (qib_cmp24(qp->s_psn, psn) <= 0) {
1250                         qp->s_state = OP(SEND_LAST);
1251                         qp->s_psn = psn + 1;
1252                 }
1253                 if (qp->s_flags & QIB_S_WAIT_ACK) {
1254                         qp->s_flags &= ~QIB_S_WAIT_ACK;
1255                         qib_schedule_send(qp);
1256                 }
1257                 qib_get_credit(qp, aeth);
1258                 qp->s_rnr_retry = qp->s_rnr_retry_cnt;
1259                 qp->s_retry = qp->s_retry_cnt;
1260                 update_last_psn(qp, psn);
1261                 ret = 1;
1262                 goto bail;
1263
1264         case 1:         /* RNR NAK */
1265                 ibp->n_rnr_naks++;
1266                 if (qp->s_acked == qp->s_tail)
1267                         goto bail;
1268                 if (qp->s_flags & QIB_S_WAIT_RNR)
1269                         goto bail;
1270                 if (qp->s_rnr_retry == 0) {
1271                         status = IB_WC_RNR_RETRY_EXC_ERR;
1272                         goto class_b;
1273                 }
1274                 if (qp->s_rnr_retry_cnt < 7)
1275                         qp->s_rnr_retry--;
1276
1277                 /* The last valid PSN is the previous PSN. */
1278                 update_last_psn(qp, psn - 1);
1279
1280                 ibp->n_rc_resends += (qp->s_psn - psn) & QIB_PSN_MASK;
1281
1282                 reset_psn(qp, psn);
1283
1284                 qp->s_flags &= ~(QIB_S_WAIT_SSN_CREDIT | QIB_S_WAIT_ACK);
1285                 qp->s_flags |= QIB_S_WAIT_RNR;
1286                 qp->s_timer.function = qib_rc_rnr_retry;
1287                 qp->s_timer.expires = jiffies + usecs_to_jiffies(
1288                         ib_qib_rnr_table[(aeth >> QIB_AETH_CREDIT_SHIFT) &
1289                                            QIB_AETH_CREDIT_MASK]);
1290                 add_timer(&qp->s_timer);
1291                 goto bail;
1292
1293         case 3:         /* NAK */
1294                 if (qp->s_acked == qp->s_tail)
1295                         goto bail;
1296                 /* The last valid PSN is the previous PSN. */
1297                 update_last_psn(qp, psn - 1);
1298                 switch ((aeth >> QIB_AETH_CREDIT_SHIFT) &
1299                         QIB_AETH_CREDIT_MASK) {
1300                 case 0: /* PSN sequence error */
1301                         ibp->n_seq_naks++;
1302                         /*
1303                          * Back up to the responder's expected PSN.
1304                          * Note that we might get a NAK in the middle of an
1305                          * RDMA READ response which terminates the RDMA
1306                          * READ.
1307                          */
1308                         qib_restart_rc(qp, psn, 0);
1309                         qib_schedule_send(qp);
1310                         break;
1311
1312                 case 1: /* Invalid Request */
1313                         status = IB_WC_REM_INV_REQ_ERR;
1314                         ibp->n_other_naks++;
1315                         goto class_b;
1316
1317                 case 2: /* Remote Access Error */
1318                         status = IB_WC_REM_ACCESS_ERR;
1319                         ibp->n_other_naks++;
1320                         goto class_b;
1321
1322                 case 3: /* Remote Operation Error */
1323                         status = IB_WC_REM_OP_ERR;
1324                         ibp->n_other_naks++;
1325 class_b:
1326                         if (qp->s_last == qp->s_acked) {
1327                                 qib_send_complete(qp, wqe, status);
1328                                 qib_error_qp(qp, IB_WC_WR_FLUSH_ERR);
1329                         }
1330                         break;
1331
1332                 default:
1333                         /* Ignore other reserved NAK error codes */
1334                         goto reserved;
1335                 }
1336                 qp->s_retry = qp->s_retry_cnt;
1337                 qp->s_rnr_retry = qp->s_rnr_retry_cnt;
1338                 goto bail;
1339
1340         default:                /* 2: reserved */
1341 reserved:
1342                 /* Ignore reserved NAK codes. */
1343                 goto bail;
1344         }
1345
1346 bail:
1347         return ret;
1348 }
1349
1350 /*
1351  * We have seen an out of sequence RDMA read middle or last packet.
1352  * This ACKs SENDs and RDMA writes up to the first RDMA read or atomic SWQE.
1353  */
1354 static void rdma_seq_err(struct qib_qp *qp, struct qib_ibport *ibp, u32 psn,
1355                          struct qib_ctxtdata *rcd)
1356 {
1357         struct qib_swqe *wqe;
1358
1359         /* Remove QP from retry timer */
1360         if (qp->s_flags & (QIB_S_TIMER | QIB_S_WAIT_RNR)) {
1361                 qp->s_flags &= ~(QIB_S_TIMER | QIB_S_WAIT_RNR);
1362                 del_timer(&qp->s_timer);
1363         }
1364
1365         wqe = get_swqe_ptr(qp, qp->s_acked);
1366
1367         while (qib_cmp24(psn, wqe->lpsn) > 0) {
1368                 if (wqe->wr.opcode == IB_WR_RDMA_READ ||
1369                     wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1370                     wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)
1371                         break;
1372                 wqe = do_rc_completion(qp, wqe, ibp);
1373         }
1374
1375         ibp->n_rdma_seq++;
1376         qp->r_flags |= QIB_R_RDMAR_SEQ;
1377         qib_restart_rc(qp, qp->s_last_psn + 1, 0);
1378         if (list_empty(&qp->rspwait)) {
1379                 qp->r_flags |= QIB_R_RSP_SEND;
1380                 atomic_inc(&qp->refcount);
1381                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
1382         }
1383 }
1384
1385 /**
1386  * qib_rc_rcv_resp - process an incoming RC response packet
1387  * @ibp: the port this packet came in on
1388  * @ohdr: the other headers for this packet
1389  * @data: the packet data
1390  * @tlen: the packet length
1391  * @qp: the QP for this packet
1392  * @opcode: the opcode for this packet
1393  * @psn: the packet sequence number for this packet
1394  * @hdrsize: the header length
1395  * @pmtu: the path MTU
1396  *
1397  * This is called from qib_rc_rcv() to process an incoming RC response
1398  * packet for the given QP.
1399  * Called at interrupt level.
1400  */
1401 static void qib_rc_rcv_resp(struct qib_ibport *ibp,
1402                             struct qib_other_headers *ohdr,
1403                             void *data, u32 tlen,
1404                             struct qib_qp *qp,
1405                             u32 opcode,
1406                             u32 psn, u32 hdrsize, u32 pmtu,
1407                             struct qib_ctxtdata *rcd)
1408 {
1409         struct qib_swqe *wqe;
1410         enum ib_wc_status status;
1411         unsigned long flags;
1412         int diff;
1413         u32 pad;
1414         u32 aeth;
1415         u64 val;
1416
1417         spin_lock_irqsave(&qp->s_lock, flags);
1418
1419         /* Ignore invalid responses. */
1420         if (qib_cmp24(psn, qp->s_next_psn) >= 0)
1421                 goto ack_done;
1422
1423         /* Ignore duplicate responses. */
1424         diff = qib_cmp24(psn, qp->s_last_psn);
1425         if (unlikely(diff <= 0)) {
1426                 /* Update credits for "ghost" ACKs */
1427                 if (diff == 0 && opcode == OP(ACKNOWLEDGE)) {
1428                         aeth = be32_to_cpu(ohdr->u.aeth);
1429                         if ((aeth >> 29) == 0)
1430                                 qib_get_credit(qp, aeth);
1431                 }
1432                 goto ack_done;
1433         }
1434
1435         /*
1436          * Skip everything other than the PSN we expect, if we are waiting
1437          * for a reply to a restarted RDMA read or atomic op.
1438          */
1439         if (qp->r_flags & QIB_R_RDMAR_SEQ) {
1440                 if (qib_cmp24(psn, qp->s_last_psn + 1) != 0)
1441                         goto ack_done;
1442                 qp->r_flags &= ~QIB_R_RDMAR_SEQ;
1443         }
1444
1445         if (unlikely(qp->s_acked == qp->s_tail))
1446                 goto ack_done;
1447         wqe = get_swqe_ptr(qp, qp->s_acked);
1448         status = IB_WC_SUCCESS;
1449
1450         switch (opcode) {
1451         case OP(ACKNOWLEDGE):
1452         case OP(ATOMIC_ACKNOWLEDGE):
1453         case OP(RDMA_READ_RESPONSE_FIRST):
1454                 aeth = be32_to_cpu(ohdr->u.aeth);
1455                 if (opcode == OP(ATOMIC_ACKNOWLEDGE)) {
1456                         __be32 *p = ohdr->u.at.atomic_ack_eth;
1457
1458                         val = ((u64) be32_to_cpu(p[0]) << 32) |
1459                                 be32_to_cpu(p[1]);
1460                 } else
1461                         val = 0;
1462                 if (!do_rc_ack(qp, aeth, psn, opcode, val, rcd) ||
1463                     opcode != OP(RDMA_READ_RESPONSE_FIRST))
1464                         goto ack_done;
1465                 hdrsize += 4;
1466                 wqe = get_swqe_ptr(qp, qp->s_acked);
1467                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1468                         goto ack_op_err;
1469                 /*
1470                  * If this is a response to a resent RDMA read, we
1471                  * have to be careful to copy the data to the right
1472                  * location.
1473                  */
1474                 qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
1475                                                   wqe, psn, pmtu);
1476                 goto read_middle;
1477
1478         case OP(RDMA_READ_RESPONSE_MIDDLE):
1479                 /* no AETH, no ACK */
1480                 if (unlikely(qib_cmp24(psn, qp->s_last_psn + 1)))
1481                         goto ack_seq_err;
1482                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1483                         goto ack_op_err;
1484 read_middle:
1485                 if (unlikely(tlen != (hdrsize + pmtu + 4)))
1486                         goto ack_len_err;
1487                 if (unlikely(pmtu >= qp->s_rdma_read_len))
1488                         goto ack_len_err;
1489
1490                 /*
1491                  * We got a response so update the timeout.
1492                  * 4.096 usec. * (1 << qp->timeout)
1493                  */
1494                 qp->s_flags |= QIB_S_TIMER;
1495                 mod_timer(&qp->s_timer, jiffies +
1496                         usecs_to_jiffies((4096UL * (1UL << qp->timeout)) /
1497                                          1000UL));
1498                 if (qp->s_flags & QIB_S_WAIT_ACK) {
1499                         qp->s_flags &= ~QIB_S_WAIT_ACK;
1500                         qib_schedule_send(qp);
1501                 }
1502
1503                 if (opcode == OP(RDMA_READ_RESPONSE_MIDDLE))
1504                         qp->s_retry = qp->s_retry_cnt;
1505
1506                 /*
1507                  * Update the RDMA receive state but do the copy w/o
1508                  * holding the locks and blocking interrupts.
1509                  */
1510                 qp->s_rdma_read_len -= pmtu;
1511                 update_last_psn(qp, psn);
1512                 spin_unlock_irqrestore(&qp->s_lock, flags);
1513                 qib_copy_sge(&qp->s_rdma_read_sge, data, pmtu, 0);
1514                 goto bail;
1515
1516         case OP(RDMA_READ_RESPONSE_ONLY):
1517                 aeth = be32_to_cpu(ohdr->u.aeth);
1518                 if (!do_rc_ack(qp, aeth, psn, opcode, 0, rcd))
1519                         goto ack_done;
1520                 /* Get the number of bytes the message was padded by. */
1521                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1522                 /*
1523                  * Check that the data size is >= 0 && <= pmtu.
1524                  * Remember to account for the AETH header (4) and
1525                  * ICRC (4).
1526                  */
1527                 if (unlikely(tlen < (hdrsize + pad + 8)))
1528                         goto ack_len_err;
1529                 /*
1530                  * If this is a response to a resent RDMA read, we
1531                  * have to be careful to copy the data to the right
1532                  * location.
1533                  */
1534                 wqe = get_swqe_ptr(qp, qp->s_acked);
1535                 qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
1536                                                   wqe, psn, pmtu);
1537                 goto read_last;
1538
1539         case OP(RDMA_READ_RESPONSE_LAST):
1540                 /* ACKs READ req. */
1541                 if (unlikely(qib_cmp24(psn, qp->s_last_psn + 1)))
1542                         goto ack_seq_err;
1543                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1544                         goto ack_op_err;
1545                 /* Get the number of bytes the message was padded by. */
1546                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1547                 /*
1548                  * Check that the data size is >= 1 && <= pmtu.
1549                  * Remember to account for the AETH header (4) and
1550                  * ICRC (4).
1551                  */
1552                 if (unlikely(tlen <= (hdrsize + pad + 8)))
1553                         goto ack_len_err;
1554 read_last:
1555                 tlen -= hdrsize + pad + 8;
1556                 if (unlikely(tlen != qp->s_rdma_read_len))
1557                         goto ack_len_err;
1558                 aeth = be32_to_cpu(ohdr->u.aeth);
1559                 qib_copy_sge(&qp->s_rdma_read_sge, data, tlen, 0);
1560                 WARN_ON(qp->s_rdma_read_sge.num_sge);
1561                 (void) do_rc_ack(qp, aeth, psn,
1562                                  OP(RDMA_READ_RESPONSE_LAST), 0, rcd);
1563                 goto ack_done;
1564         }
1565
1566 ack_op_err:
1567         status = IB_WC_LOC_QP_OP_ERR;
1568         goto ack_err;
1569
1570 ack_seq_err:
1571         rdma_seq_err(qp, ibp, psn, rcd);
1572         goto ack_done;
1573
1574 ack_len_err:
1575         status = IB_WC_LOC_LEN_ERR;
1576 ack_err:
1577         if (qp->s_last == qp->s_acked) {
1578                 qib_send_complete(qp, wqe, status);
1579                 qib_error_qp(qp, IB_WC_WR_FLUSH_ERR);
1580         }
1581 ack_done:
1582         spin_unlock_irqrestore(&qp->s_lock, flags);
1583 bail:
1584         return;
1585 }
1586
1587 /**
1588  * qib_rc_rcv_error - process an incoming duplicate or error RC packet
1589  * @ohdr: the other headers for this packet
1590  * @data: the packet data
1591  * @qp: the QP for this packet
1592  * @opcode: the opcode for this packet
1593  * @psn: the packet sequence number for this packet
1594  * @diff: the difference between the PSN and the expected PSN
1595  *
1596  * This is called from qib_rc_rcv() to process an unexpected
1597  * incoming RC packet for the given QP.
1598  * Called at interrupt level.
1599  * Return 1 if no more processing is needed; otherwise return 0 to
1600  * schedule a response to be sent.
1601  */
1602 static int qib_rc_rcv_error(struct qib_other_headers *ohdr,
1603                             void *data,
1604                             struct qib_qp *qp,
1605                             u32 opcode,
1606                             u32 psn,
1607                             int diff,
1608                             struct qib_ctxtdata *rcd)
1609 {
1610         struct qib_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
1611         struct qib_ack_entry *e;
1612         unsigned long flags;
1613         u8 i, prev;
1614         int old_req;
1615
1616         if (diff > 0) {
1617                 /*
1618                  * Packet sequence error.
1619                  * A NAK will ACK earlier sends and RDMA writes.
1620                  * Don't queue the NAK if we already sent one.
1621                  */
1622                 if (!qp->r_nak_state) {
1623                         ibp->n_rc_seqnak++;
1624                         qp->r_nak_state = IB_NAK_PSN_ERROR;
1625                         /* Use the expected PSN. */
1626                         qp->r_ack_psn = qp->r_psn;
1627                         /*
1628                          * Wait to send the sequence NAK until all packets
1629                          * in the receive queue have been processed.
1630                          * Otherwise, we end up propagating congestion.
1631                          */
1632                         if (list_empty(&qp->rspwait)) {
1633                                 qp->r_flags |= QIB_R_RSP_NAK;
1634                                 atomic_inc(&qp->refcount);
1635                                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
1636                         }
1637                 }
1638                 goto done;
1639         }
1640
1641         /*
1642          * Handle a duplicate request.  Don't re-execute SEND, RDMA
1643          * write or atomic op.  Don't NAK errors, just silently drop
1644          * the duplicate request.  Note that r_sge, r_len, and
1645          * r_rcv_len may be in use so don't modify them.
1646          *
1647          * We are supposed to ACK the earliest duplicate PSN but we
1648          * can coalesce an outstanding duplicate ACK.  We have to
1649          * send the earliest so that RDMA reads can be restarted at
1650          * the requester's expected PSN.
1651          *
1652          * First, find where this duplicate PSN falls within the
1653          * ACKs previously sent.
1654          * old_req is true if there is an older response that is scheduled
1655          * to be sent before sending this one.
1656          */
1657         e = NULL;
1658         old_req = 1;
1659         ibp->n_rc_dupreq++;
1660
1661         spin_lock_irqsave(&qp->s_lock, flags);
1662
1663         for (i = qp->r_head_ack_queue; ; i = prev) {
1664                 if (i == qp->s_tail_ack_queue)
1665                         old_req = 0;
1666                 if (i)
1667                         prev = i - 1;
1668                 else
1669                         prev = QIB_MAX_RDMA_ATOMIC;
1670                 if (prev == qp->r_head_ack_queue) {
1671                         e = NULL;
1672                         break;
1673                 }
1674                 e = &qp->s_ack_queue[prev];
1675                 if (!e->opcode) {
1676                         e = NULL;
1677                         break;
1678                 }
1679                 if (qib_cmp24(psn, e->psn) >= 0) {
1680                         if (prev == qp->s_tail_ack_queue &&
1681                             qib_cmp24(psn, e->lpsn) <= 0)
1682                                 old_req = 0;
1683                         break;
1684                 }
1685         }
1686         switch (opcode) {
1687         case OP(RDMA_READ_REQUEST): {
1688                 struct ib_reth *reth;
1689                 u32 offset;
1690                 u32 len;
1691
1692                 /*
1693                  * If we didn't find the RDMA read request in the ack queue,
1694                  * we can ignore this request.
1695                  */
1696                 if (!e || e->opcode != OP(RDMA_READ_REQUEST))
1697                         goto unlock_done;
1698                 /* RETH comes after BTH */
1699                 reth = &ohdr->u.rc.reth;
1700                 /*
1701                  * Address range must be a subset of the original
1702                  * request and start on pmtu boundaries.
1703                  * We reuse the old ack_queue slot since the requester
1704                  * should not back up and request an earlier PSN for the
1705                  * same request.
1706                  */
1707                 offset = ((psn - e->psn) & QIB_PSN_MASK) *
1708                         ib_mtu_enum_to_int(qp->path_mtu);
1709                 len = be32_to_cpu(reth->length);
1710                 if (unlikely(offset + len != e->rdma_sge.sge_length))
1711                         goto unlock_done;
1712                 if (e->rdma_sge.mr) {
1713                         atomic_dec(&e->rdma_sge.mr->refcount);
1714                         e->rdma_sge.mr = NULL;
1715                 }
1716                 if (len != 0) {
1717                         u32 rkey = be32_to_cpu(reth->rkey);
1718                         u64 vaddr = be64_to_cpu(reth->vaddr);
1719                         int ok;
1720
1721                         ok = qib_rkey_ok(qp, &e->rdma_sge, len, vaddr, rkey,
1722                                          IB_ACCESS_REMOTE_READ);
1723                         if (unlikely(!ok))
1724                                 goto unlock_done;
1725                 } else {
1726                         e->rdma_sge.vaddr = NULL;
1727                         e->rdma_sge.length = 0;
1728                         e->rdma_sge.sge_length = 0;
1729                 }
1730                 e->psn = psn;
1731                 if (old_req)
1732                         goto unlock_done;
1733                 qp->s_tail_ack_queue = prev;
1734                 break;
1735         }
1736
1737         case OP(COMPARE_SWAP):
1738         case OP(FETCH_ADD): {
1739                 /*
1740                  * If we didn't find the atomic request in the ack queue
1741                  * or the send tasklet is already backed up to send an
1742                  * earlier entry, we can ignore this request.
1743                  */
1744                 if (!e || e->opcode != (u8) opcode || old_req)
1745                         goto unlock_done;
1746                 qp->s_tail_ack_queue = prev;
1747                 break;
1748         }
1749
1750         default:
1751                 /*
1752                  * Ignore this operation if it doesn't request an ACK
1753                  * or an earlier RDMA read or atomic is going to be resent.
1754                  */
1755                 if (!(psn & IB_BTH_REQ_ACK) || old_req)
1756                         goto unlock_done;
1757                 /*
1758                  * Resend the most recent ACK if this request is
1759                  * after all the previous RDMA reads and atomics.
1760                  */
1761                 if (i == qp->r_head_ack_queue) {
1762                         spin_unlock_irqrestore(&qp->s_lock, flags);
1763                         qp->r_nak_state = 0;
1764                         qp->r_ack_psn = qp->r_psn - 1;
1765                         goto send_ack;
1766                 }
1767                 if (!(qp->s_flags & QIB_S_RESP_PENDING)) {
1768                         spin_unlock_irqrestore(&qp->s_lock, flags);
1769                         qp->r_nak_state = 0;
1770                         qp->r_ack_psn = qp->s_ack_queue[i].psn - 1;
1771                         goto send_ack;
1772                 }
1773                 /*
1774                  * Resend the RDMA read or atomic op which
1775                  * ACKs this duplicate request.
1776                  */
1777                 qp->s_tail_ack_queue = i;
1778                 break;
1779         }
1780         qp->s_ack_state = OP(ACKNOWLEDGE);
1781         qp->s_flags |= QIB_S_RESP_PENDING;
1782         qp->r_nak_state = 0;
1783         qib_schedule_send(qp);
1784
1785 unlock_done:
1786         spin_unlock_irqrestore(&qp->s_lock, flags);
1787 done:
1788         return 1;
1789
1790 send_ack:
1791         return 0;
1792 }
1793
1794 void qib_rc_error(struct qib_qp *qp, enum ib_wc_status err)
1795 {
1796         unsigned long flags;
1797         int lastwqe;
1798
1799         spin_lock_irqsave(&qp->s_lock, flags);
1800         lastwqe = qib_error_qp(qp, err);
1801         spin_unlock_irqrestore(&qp->s_lock, flags);
1802
1803         if (lastwqe) {
1804                 struct ib_event ev;
1805
1806                 ev.device = qp->ibqp.device;
1807                 ev.element.qp = &qp->ibqp;
1808                 ev.event = IB_EVENT_QP_LAST_WQE_REACHED;
1809                 qp->ibqp.event_handler(&ev, qp->ibqp.qp_context);
1810         }
1811 }
1812
1813 static inline void qib_update_ack_queue(struct qib_qp *qp, unsigned n)
1814 {
1815         unsigned next;
1816
1817         next = n + 1;
1818         if (next > QIB_MAX_RDMA_ATOMIC)
1819                 next = 0;
1820         qp->s_tail_ack_queue = next;
1821         qp->s_ack_state = OP(ACKNOWLEDGE);
1822 }
1823
1824 /**
1825  * qib_rc_rcv - process an incoming RC packet
1826  * @rcd: the context pointer
1827  * @hdr: the header of this packet
1828  * @has_grh: true if the header has a GRH
1829  * @data: the packet data
1830  * @tlen: the packet length
1831  * @qp: the QP for this packet
1832  *
1833  * This is called from qib_qp_rcv() to process an incoming RC packet
1834  * for the given QP.
1835  * Called at interrupt level.
1836  */
1837 void qib_rc_rcv(struct qib_ctxtdata *rcd, struct qib_ib_header *hdr,
1838                 int has_grh, void *data, u32 tlen, struct qib_qp *qp)
1839 {
1840         struct qib_ibport *ibp = &rcd->ppd->ibport_data;
1841         struct qib_other_headers *ohdr;
1842         u32 opcode;
1843         u32 hdrsize;
1844         u32 psn;
1845         u32 pad;
1846         struct ib_wc wc;
1847         u32 pmtu = ib_mtu_enum_to_int(qp->path_mtu);
1848         int diff;
1849         struct ib_reth *reth;
1850         unsigned long flags;
1851         int ret;
1852
1853         /* Check for GRH */
1854         if (!has_grh) {
1855                 ohdr = &hdr->u.oth;
1856                 hdrsize = 8 + 12;       /* LRH + BTH */
1857         } else {
1858                 ohdr = &hdr->u.l.oth;
1859                 hdrsize = 8 + 40 + 12;  /* LRH + GRH + BTH */
1860         }
1861
1862         opcode = be32_to_cpu(ohdr->bth[0]);
1863         spin_lock_irqsave(&qp->s_lock, flags);
1864         if (qib_ruc_check_hdr(ibp, hdr, has_grh, qp, opcode))
1865                 goto sunlock;
1866         spin_unlock_irqrestore(&qp->s_lock, flags);
1867
1868         psn = be32_to_cpu(ohdr->bth[2]);
1869         opcode >>= 24;
1870
1871         /*
1872          * Process responses (ACKs) before anything else.  Note that the
1873          * packet sequence number will be for something in the send work
1874          * queue rather than the expected receive packet sequence number.
1875          * In other words, this QP is the requester.
1876          */
1877         if (opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
1878             opcode <= OP(ATOMIC_ACKNOWLEDGE)) {
1879                 qib_rc_rcv_resp(ibp, ohdr, data, tlen, qp, opcode, psn,
1880                                 hdrsize, pmtu, rcd);
1881                 return;
1882         }
1883
1884         /* Compute 24 bits worth of difference. */
1885         diff = qib_cmp24(psn, qp->r_psn);
1886         if (unlikely(diff)) {
1887                 if (qib_rc_rcv_error(ohdr, data, qp, opcode, psn, diff, rcd))
1888                         return;
1889                 goto send_ack;
1890         }
1891
1892         /* Check for opcode sequence errors. */
1893         switch (qp->r_state) {
1894         case OP(SEND_FIRST):
1895         case OP(SEND_MIDDLE):
1896                 if (opcode == OP(SEND_MIDDLE) ||
1897                     opcode == OP(SEND_LAST) ||
1898                     opcode == OP(SEND_LAST_WITH_IMMEDIATE))
1899                         break;
1900                 goto nack_inv;
1901
1902         case OP(RDMA_WRITE_FIRST):
1903         case OP(RDMA_WRITE_MIDDLE):
1904                 if (opcode == OP(RDMA_WRITE_MIDDLE) ||
1905                     opcode == OP(RDMA_WRITE_LAST) ||
1906                     opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
1907                         break;
1908                 goto nack_inv;
1909
1910         default:
1911                 if (opcode == OP(SEND_MIDDLE) ||
1912                     opcode == OP(SEND_LAST) ||
1913                     opcode == OP(SEND_LAST_WITH_IMMEDIATE) ||
1914                     opcode == OP(RDMA_WRITE_MIDDLE) ||
1915                     opcode == OP(RDMA_WRITE_LAST) ||
1916                     opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
1917                         goto nack_inv;
1918                 /*
1919                  * Note that it is up to the requester to not send a new
1920                  * RDMA read or atomic operation before receiving an ACK
1921                  * for the previous operation.
1922                  */
1923                 break;
1924         }
1925
1926         memset(&wc, 0, sizeof wc);
1927
1928         if (qp->state == IB_QPS_RTR && !(qp->r_flags & QIB_R_COMM_EST)) {
1929                 qp->r_flags |= QIB_R_COMM_EST;
1930                 if (qp->ibqp.event_handler) {
1931                         struct ib_event ev;
1932
1933                         ev.device = qp->ibqp.device;
1934                         ev.element.qp = &qp->ibqp;
1935                         ev.event = IB_EVENT_COMM_EST;
1936                         qp->ibqp.event_handler(&ev, qp->ibqp.qp_context);
1937                 }
1938         }
1939
1940         /* OK, process the packet. */
1941         switch (opcode) {
1942         case OP(SEND_FIRST):
1943                 ret = qib_get_rwqe(qp, 0);
1944                 if (ret < 0)
1945                         goto nack_op_err;
1946                 if (!ret)
1947                         goto rnr_nak;
1948                 qp->r_rcv_len = 0;
1949                 /* FALLTHROUGH */
1950         case OP(SEND_MIDDLE):
1951         case OP(RDMA_WRITE_MIDDLE):
1952 send_middle:
1953                 /* Check for invalid length PMTU or posted rwqe len. */
1954                 if (unlikely(tlen != (hdrsize + pmtu + 4)))
1955                         goto nack_inv;
1956                 qp->r_rcv_len += pmtu;
1957                 if (unlikely(qp->r_rcv_len > qp->r_len))
1958                         goto nack_inv;
1959                 qib_copy_sge(&qp->r_sge, data, pmtu, 1);
1960                 break;
1961
1962         case OP(RDMA_WRITE_LAST_WITH_IMMEDIATE):
1963                 /* consume RWQE */
1964                 ret = qib_get_rwqe(qp, 1);
1965                 if (ret < 0)
1966                         goto nack_op_err;
1967                 if (!ret)
1968                         goto rnr_nak;
1969                 goto send_last_imm;
1970
1971         case OP(SEND_ONLY):
1972         case OP(SEND_ONLY_WITH_IMMEDIATE):
1973                 ret = qib_get_rwqe(qp, 0);
1974                 if (ret < 0)
1975                         goto nack_op_err;
1976                 if (!ret)
1977                         goto rnr_nak;
1978                 qp->r_rcv_len = 0;
1979                 if (opcode == OP(SEND_ONLY))
1980                         goto send_last;
1981                 /* FALLTHROUGH */
1982         case OP(SEND_LAST_WITH_IMMEDIATE):
1983 send_last_imm:
1984                 wc.ex.imm_data = ohdr->u.imm_data;
1985                 hdrsize += 4;
1986                 wc.wc_flags = IB_WC_WITH_IMM;
1987                 /* FALLTHROUGH */
1988         case OP(SEND_LAST):
1989         case OP(RDMA_WRITE_LAST):
1990 send_last:
1991                 /* Get the number of bytes the message was padded by. */
1992                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1993                 /* Check for invalid length. */
1994                 if (unlikely(tlen < (hdrsize + pad + 4)))
1995                         goto nack_inv;
1996                 /* Don't count the CRC. */
1997                 tlen -= (hdrsize + pad + 4);
1998                 wc.byte_len = tlen + qp->r_rcv_len;
1999                 if (unlikely(wc.byte_len > qp->r_len))
2000                         goto nack_inv;
2001                 qib_copy_sge(&qp->r_sge, data, tlen, 1);
2002                 while (qp->r_sge.num_sge) {
2003                         atomic_dec(&qp->r_sge.sge.mr->refcount);
2004                         if (--qp->r_sge.num_sge)
2005                                 qp->r_sge.sge = *qp->r_sge.sg_list++;
2006                 }
2007                 qp->r_msn++;
2008                 if (!test_and_clear_bit(QIB_R_WRID_VALID, &qp->r_aflags))
2009                         break;
2010                 wc.wr_id = qp->r_wr_id;
2011                 wc.status = IB_WC_SUCCESS;
2012                 if (opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE) ||
2013                     opcode == OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE))
2014                         wc.opcode = IB_WC_RECV_RDMA_WITH_IMM;
2015                 else
2016                         wc.opcode = IB_WC_RECV;
2017                 wc.qp = &qp->ibqp;
2018                 wc.src_qp = qp->remote_qpn;
2019                 wc.slid = qp->remote_ah_attr.dlid;
2020                 wc.sl = qp->remote_ah_attr.sl;
2021                 /* Signal completion event if the solicited bit is set. */
2022                 qib_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
2023                              (ohdr->bth[0] &
2024                               cpu_to_be32(IB_BTH_SOLICITED)) != 0);
2025                 break;
2026
2027         case OP(RDMA_WRITE_FIRST):
2028         case OP(RDMA_WRITE_ONLY):
2029         case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE):
2030                 if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_WRITE)))
2031                         goto nack_inv;
2032                 /* consume RWQE */
2033                 reth = &ohdr->u.rc.reth;
2034                 hdrsize += sizeof(*reth);
2035                 qp->r_len = be32_to_cpu(reth->length);
2036                 qp->r_rcv_len = 0;
2037                 qp->r_sge.sg_list = NULL;
2038                 if (qp->r_len != 0) {
2039                         u32 rkey = be32_to_cpu(reth->rkey);
2040                         u64 vaddr = be64_to_cpu(reth->vaddr);
2041                         int ok;
2042
2043                         /* Check rkey & NAK */
2044                         ok = qib_rkey_ok(qp, &qp->r_sge.sge, qp->r_len, vaddr,
2045                                          rkey, IB_ACCESS_REMOTE_WRITE);
2046                         if (unlikely(!ok))
2047                                 goto nack_acc;
2048                         qp->r_sge.num_sge = 1;
2049                 } else {
2050                         qp->r_sge.num_sge = 0;
2051                         qp->r_sge.sge.mr = NULL;
2052                         qp->r_sge.sge.vaddr = NULL;
2053                         qp->r_sge.sge.length = 0;
2054                         qp->r_sge.sge.sge_length = 0;
2055                 }
2056                 if (opcode == OP(RDMA_WRITE_FIRST))
2057                         goto send_middle;
2058                 else if (opcode == OP(RDMA_WRITE_ONLY))
2059                         goto send_last;
2060                 ret = qib_get_rwqe(qp, 1);
2061                 if (ret < 0)
2062                         goto nack_op_err;
2063                 if (!ret)
2064                         goto rnr_nak;
2065                 goto send_last_imm;
2066
2067         case OP(RDMA_READ_REQUEST): {
2068                 struct qib_ack_entry *e;
2069                 u32 len;
2070                 u8 next;
2071
2072                 if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_READ)))
2073                         goto nack_inv;
2074                 next = qp->r_head_ack_queue + 1;
2075                 /* s_ack_queue is size QIB_MAX_RDMA_ATOMIC+1 so use > not >= */
2076                 if (next > QIB_MAX_RDMA_ATOMIC)
2077                         next = 0;
2078                 spin_lock_irqsave(&qp->s_lock, flags);
2079                 if (unlikely(next == qp->s_tail_ack_queue)) {
2080                         if (!qp->s_ack_queue[next].sent)
2081                                 goto nack_inv_unlck;
2082                         qib_update_ack_queue(qp, next);
2083                 }
2084                 e = &qp->s_ack_queue[qp->r_head_ack_queue];
2085                 if (e->opcode == OP(RDMA_READ_REQUEST) && e->rdma_sge.mr) {
2086                         atomic_dec(&e->rdma_sge.mr->refcount);
2087                         e->rdma_sge.mr = NULL;
2088                 }
2089                 reth = &ohdr->u.rc.reth;
2090                 len = be32_to_cpu(reth->length);
2091                 if (len) {
2092                         u32 rkey = be32_to_cpu(reth->rkey);
2093                         u64 vaddr = be64_to_cpu(reth->vaddr);
2094                         int ok;
2095
2096                         /* Check rkey & NAK */
2097                         ok = qib_rkey_ok(qp, &e->rdma_sge, len, vaddr,
2098                                          rkey, IB_ACCESS_REMOTE_READ);
2099                         if (unlikely(!ok))
2100                                 goto nack_acc_unlck;
2101                         /*
2102                          * Update the next expected PSN.  We add 1 later
2103                          * below, so only add the remainder here.
2104                          */
2105                         if (len > pmtu)
2106                                 qp->r_psn += (len - 1) / pmtu;
2107                 } else {
2108                         e->rdma_sge.mr = NULL;
2109                         e->rdma_sge.vaddr = NULL;
2110                         e->rdma_sge.length = 0;
2111                         e->rdma_sge.sge_length = 0;
2112                 }
2113                 e->opcode = opcode;
2114                 e->sent = 0;
2115                 e->psn = psn;
2116                 e->lpsn = qp->r_psn;
2117                 /*
2118                  * We need to increment the MSN here instead of when we
2119                  * finish sending the result since a duplicate request would
2120                  * increment it more than once.
2121                  */
2122                 qp->r_msn++;
2123                 qp->r_psn++;
2124                 qp->r_state = opcode;
2125                 qp->r_nak_state = 0;
2126                 qp->r_head_ack_queue = next;
2127
2128                 /* Schedule the send tasklet. */
2129                 qp->s_flags |= QIB_S_RESP_PENDING;
2130                 qib_schedule_send(qp);
2131
2132                 goto sunlock;
2133         }
2134
2135         case OP(COMPARE_SWAP):
2136         case OP(FETCH_ADD): {
2137                 struct ib_atomic_eth *ateth;
2138                 struct qib_ack_entry *e;
2139                 u64 vaddr;
2140                 atomic64_t *maddr;
2141                 u64 sdata;
2142                 u32 rkey;
2143                 u8 next;
2144
2145                 if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_ATOMIC)))
2146                         goto nack_inv;
2147                 next = qp->r_head_ack_queue + 1;
2148                 if (next > QIB_MAX_RDMA_ATOMIC)
2149                         next = 0;
2150                 spin_lock_irqsave(&qp->s_lock, flags);
2151                 if (unlikely(next == qp->s_tail_ack_queue)) {
2152                         if (!qp->s_ack_queue[next].sent)
2153                                 goto nack_inv_unlck;
2154                         qib_update_ack_queue(qp, next);
2155                 }
2156                 e = &qp->s_ack_queue[qp->r_head_ack_queue];
2157                 if (e->opcode == OP(RDMA_READ_REQUEST) && e->rdma_sge.mr) {
2158                         atomic_dec(&e->rdma_sge.mr->refcount);
2159                         e->rdma_sge.mr = NULL;
2160                 }
2161                 ateth = &ohdr->u.atomic_eth;
2162                 vaddr = ((u64) be32_to_cpu(ateth->vaddr[0]) << 32) |
2163                         be32_to_cpu(ateth->vaddr[1]);
2164                 if (unlikely(vaddr & (sizeof(u64) - 1)))
2165                         goto nack_inv_unlck;
2166                 rkey = be32_to_cpu(ateth->rkey);
2167                 /* Check rkey & NAK */
2168                 if (unlikely(!qib_rkey_ok(qp, &qp->r_sge.sge, sizeof(u64),
2169                                           vaddr, rkey,
2170                                           IB_ACCESS_REMOTE_ATOMIC)))
2171                         goto nack_acc_unlck;
2172                 /* Perform atomic OP and save result. */
2173                 maddr = (atomic64_t *) qp->r_sge.sge.vaddr;
2174                 sdata = be64_to_cpu(ateth->swap_data);
2175                 e->atomic_data = (opcode == OP(FETCH_ADD)) ?
2176                         (u64) atomic64_add_return(sdata, maddr) - sdata :
2177                         (u64) cmpxchg((u64 *) qp->r_sge.sge.vaddr,
2178                                       be64_to_cpu(ateth->compare_data),
2179                                       sdata);
2180                 atomic_dec(&qp->r_sge.sge.mr->refcount);
2181                 qp->r_sge.num_sge = 0;
2182                 e->opcode = opcode;
2183                 e->sent = 0;
2184                 e->psn = psn;
2185                 e->lpsn = psn;
2186                 qp->r_msn++;
2187                 qp->r_psn++;
2188                 qp->r_state = opcode;
2189                 qp->r_nak_state = 0;
2190                 qp->r_head_ack_queue = next;
2191
2192                 /* Schedule the send tasklet. */
2193                 qp->s_flags |= QIB_S_RESP_PENDING;
2194                 qib_schedule_send(qp);
2195
2196                 goto sunlock;
2197         }
2198
2199         default:
2200                 /* NAK unknown opcodes. */
2201                 goto nack_inv;
2202         }
2203         qp->r_psn++;
2204         qp->r_state = opcode;
2205         qp->r_ack_psn = psn;
2206         qp->r_nak_state = 0;
2207         /* Send an ACK if requested or required. */
2208         if (psn & (1 << 31))
2209                 goto send_ack;
2210         return;
2211
2212 rnr_nak:
2213         qp->r_nak_state = IB_RNR_NAK | qp->r_min_rnr_timer;
2214         qp->r_ack_psn = qp->r_psn;
2215         /* Queue RNR NAK for later */
2216         if (list_empty(&qp->rspwait)) {
2217                 qp->r_flags |= QIB_R_RSP_NAK;
2218                 atomic_inc(&qp->refcount);
2219                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
2220         }
2221         return;
2222
2223 nack_op_err:
2224         qib_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
2225         qp->r_nak_state = IB_NAK_REMOTE_OPERATIONAL_ERROR;
2226         qp->r_ack_psn = qp->r_psn;
2227         /* Queue NAK for later */
2228         if (list_empty(&qp->rspwait)) {
2229                 qp->r_flags |= QIB_R_RSP_NAK;
2230                 atomic_inc(&qp->refcount);
2231                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
2232         }
2233         return;
2234
2235 nack_inv_unlck:
2236         spin_unlock_irqrestore(&qp->s_lock, flags);
2237 nack_inv:
2238         qib_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
2239         qp->r_nak_state = IB_NAK_INVALID_REQUEST;
2240         qp->r_ack_psn = qp->r_psn;
2241         /* Queue NAK for later */
2242         if (list_empty(&qp->rspwait)) {
2243                 qp->r_flags |= QIB_R_RSP_NAK;
2244                 atomic_inc(&qp->refcount);
2245                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
2246         }
2247         return;
2248
2249 nack_acc_unlck:
2250         spin_unlock_irqrestore(&qp->s_lock, flags);
2251 nack_acc:
2252         qib_rc_error(qp, IB_WC_LOC_PROT_ERR);
2253         qp->r_nak_state = IB_NAK_REMOTE_ACCESS_ERROR;
2254         qp->r_ack_psn = qp->r_psn;
2255 send_ack:
2256         qib_send_rc_ack(qp);
2257         return;
2258
2259 sunlock:
2260         spin_unlock_irqrestore(&qp->s_lock, flags);
2261 }