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 + qp->timeout_jiffies;
  63         add_timer(&qp->s_timer);
  64 }
  65
  66 /**
  67  * qib_make_rc_ack - construct a response packet (ACK, NAK, or RDMA read)
  68  * @dev: the device for this QP
  69  * @qp: a pointer to the QP
  70  * @ohdr: a pointer to the IB header being constructed
  71  * @pmtu: the path MTU
  72  *
  73  * Return 1 if constructed; otherwise, return 0.
  74  * Note that we are in the responder's side of the QP context.
  75  * Note the QP s_lock must be held.
  76  */
  77 static int qib_make_rc_ack(struct qib_ibdev *dev, struct qib_qp *qp,
  78                            struct qib_other_headers *ohdr, u32 pmtu)
  79 {
  80         struct qib_ack_entry *e;
  81         u32 hwords;
  82         u32 len;
  83         u32 bth0;
  84         u32 bth2;
  85
  86         /* Don't send an ACK if we aren't supposed to. */
  87         if (!(ib_qib_state_ops[qp->state] & QIB_PROCESS_RECV_OK))
  88                 goto bail;
  89
  90         /* header size in 32-bit words LRH+BTH = (8+12)/4. */
  91         hwords = 5;
  92
  93         switch (qp->s_ack_state) {
  94         case OP(RDMA_READ_RESPONSE_LAST):
  95         case OP(RDMA_READ_RESPONSE_ONLY):
  96                 e = &qp->s_ack_queue[qp->s_tail_ack_queue];
  97                 if (e->rdma_sge.mr) {
  98                         qib_put_mr(e->rdma_sge.mr);
  99                         e->rdma_sge.mr = NULL;
 100                 }
 101                 /* FALLTHROUGH */
 102         case OP(ATOMIC_ACKNOWLEDGE):
 103                 /*
 104                  * We can increment the tail pointer now that the last
 105                  * response has been sent instead of only being
 106                  * constructed.
 107                  */
 108                 if (++qp->s_tail_ack_queue > QIB_MAX_RDMA_ATOMIC)
 109                         qp->s_tail_ack_queue = 0;
 110                 /* FALLTHROUGH */
 111         case OP(SEND_ONLY):
 112         case OP(ACKNOWLEDGE):
 113                 /* Check for no next entry in the queue. */
 114                 if (qp->r_head_ack_queue == qp->s_tail_ack_queue) {
 115                         if (qp->s_flags & QIB_S_ACK_PENDING)
 116                                 goto normal;
 117                         goto bail;
 118                 }
 119
 120                 e = &qp->s_ack_queue[qp->s_tail_ack_queue];
 121                 if (e->opcode == OP(RDMA_READ_REQUEST)) {
 122                         /*
 123                          * If a RDMA read response is being resent and
 124                          * we haven't seen the duplicate request yet,
 125                          * then stop sending the remaining responses the
 126                          * responder has seen until the requester resends it.
 127                          */
 128                         len = e->rdma_sge.sge_length;
 129                         if (len && !e->rdma_sge.mr) {
 130                                 qp->s_tail_ack_queue = qp->r_head_ack_queue;
 131                                 goto bail;
 132                         }
 133                         /* Copy SGE state in case we need to resend */
 134                         qp->s_rdma_mr = e->rdma_sge.mr;
 135                         if (qp->s_rdma_mr)
 136                                 qib_get_mr(qp->s_rdma_mr);
 137                         qp->s_ack_rdma_sge.sge = e->rdma_sge;
 138                         qp->s_ack_rdma_sge.num_sge = 1;
 139                         qp->s_cur_sge = &qp->s_ack_rdma_sge;
 140                         if (len > pmtu) {
 141                                 len = pmtu;
 142                                 qp->s_ack_state = OP(RDMA_READ_RESPONSE_FIRST);
 143                         } else {
 144                                 qp->s_ack_state = OP(RDMA_READ_RESPONSE_ONLY);
 145                                 e->sent = 1;
 146                         }
 147                         ohdr->u.aeth = qib_compute_aeth(qp);
 148                         hwords++;
 149                         qp->s_ack_rdma_psn = e->psn;
 150                         bth2 = qp->s_ack_rdma_psn++ & QIB_PSN_MASK;
 151                 } else {
 152                         /* COMPARE_SWAP or FETCH_ADD */
 153                         qp->s_cur_sge = NULL;
 154                         len = 0;
 155                         qp->s_ack_state = OP(ATOMIC_ACKNOWLEDGE);
 156                         ohdr->u.at.aeth = qib_compute_aeth(qp);
 157                         ohdr->u.at.atomic_ack_eth[0] =
 158                                 cpu_to_be32(e->atomic_data >> 32);
 159                         ohdr->u.at.atomic_ack_eth[1] =
 160                                 cpu_to_be32(e->atomic_data);
 161                         hwords += sizeof(ohdr->u.at) / sizeof(u32);
 162                         bth2 = e->psn & QIB_PSN_MASK;
 163                         e->sent = 1;
 164                 }
 165                 bth0 = qp->s_ack_state << 24;
 166                 break;
 167
 168         case OP(RDMA_READ_RESPONSE_FIRST):
 169                 qp->s_ack_state = OP(RDMA_READ_RESPONSE_MIDDLE);
 170                 /* FALLTHROUGH */
 171         case OP(RDMA_READ_RESPONSE_MIDDLE):
 172                 qp->s_cur_sge = &qp->s_ack_rdma_sge;
 173                 qp->s_rdma_mr = qp->s_ack_rdma_sge.sge.mr;
 174                 if (qp->s_rdma_mr)
 175                         qib_get_mr(qp->s_rdma_mr);
 176                 len = qp->s_ack_rdma_sge.sge.sge_length;
 177                 if (len > pmtu)
 178                         len = pmtu;
 179                 else {
 180                         ohdr->u.aeth = qib_compute_aeth(qp);
 181                         hwords++;
 182                         qp->s_ack_state = OP(RDMA_READ_RESPONSE_LAST);
 183                         e = &qp->s_ack_queue[qp->s_tail_ack_queue];
 184                         e->sent = 1;
 185                 }
 186                 bth0 = qp->s_ack_state << 24;
 187                 bth2 = qp->s_ack_rdma_psn++ & QIB_PSN_MASK;
 188                 break;
 189
 190         default:
 191 normal:
 192                 /*
 193                  * Send a regular ACK.
 194                  * Set the s_ack_state so we wait until after sending
 195                  * the ACK before setting s_ack_state to ACKNOWLEDGE
 196                  * (see above).
 197                  */
 198                 qp->s_ack_state = OP(SEND_ONLY);
 199                 qp->s_flags &= ~QIB_S_ACK_PENDING;
 200                 qp->s_cur_sge = NULL;
 201                 if (qp->s_nak_state)
 202                         ohdr->u.aeth =
 203                                 cpu_to_be32((qp->r_msn & QIB_MSN_MASK) |
 204                                             (qp->s_nak_state <<
 205                                              QIB_AETH_CREDIT_SHIFT));
 206                 else
 207                         ohdr->u.aeth = qib_compute_aeth(qp);
 208                 hwords++;
 209                 len = 0;
 210                 bth0 = OP(ACKNOWLEDGE) << 24;
 211                 bth2 = qp->s_ack_psn & QIB_PSN_MASK;
 212         }
 213         qp->s_rdma_ack_cnt++;
 214         qp->s_hdrwords = hwords;
 215         qp->s_cur_size = len;
 216         qib_make_ruc_header(qp, ohdr, bth0, bth2);
 217         return 1;
 218
 219 bail:
 220         qp->s_ack_state = OP(ACKNOWLEDGE);
 221         qp->s_flags &= ~(QIB_S_RESP_PENDING | QIB_S_ACK_PENDING);
 222         return 0;
 223 }
 224
 225 /**
 226  * qib_make_rc_req - construct a request packet (SEND, RDMA r/w, ATOMIC)
 227  * @qp: a pointer to the QP
 228  *
 229  * Return 1 if constructed; otherwise, return 0.
 230  */
 231 int qib_make_rc_req(struct qib_qp *qp)
 232 {
 233         struct qib_ibdev *dev = to_idev(qp->ibqp.device);
 234         struct qib_other_headers *ohdr;
 235         struct qib_sge_state *ss;
 236         struct qib_swqe *wqe;
 237         u32 hwords;
 238         u32 len;
 239         u32 bth0;
 240         u32 bth2;
 241         u32 pmtu = qp->pmtu;
 242         char newreq;
 243         unsigned long flags;
 244         int ret = 0;
 245         int delta;
 246
 247         ohdr = &qp->s_hdr->u.oth;
 248         if (qp->remote_ah_attr.ah_flags & IB_AH_GRH)
 249                 ohdr = &qp->s_hdr->u.l.oth;
 250
 251         /*
 252          * The lock is needed to synchronize between the sending tasklet,
 253          * the receive interrupt handler, and timeout resends.
 254          */
 255         spin_lock_irqsave(&qp->s_lock, flags);
 256
 257         /* Sending responses has higher priority over sending requests. */
 258         if ((qp->s_flags & QIB_S_RESP_PENDING) &&
 259             qib_make_rc_ack(dev, qp, ohdr, pmtu))
 260                 goto done;
 261
 262         if (!(ib_qib_state_ops[qp->state] & QIB_PROCESS_SEND_OK)) {
 263                 if (!(ib_qib_state_ops[qp->state] & QIB_FLUSH_SEND))
 264                         goto bail;
 265                 /* We are in the error state, flush the work request. */
 266                 if (qp->s_last == qp->s_head)
 267                         goto bail;
 268                 /* If DMAs are in progress, we can't flush immediately. */
 269                 if (atomic_read(&qp->s_dma_busy)) {
 270                         qp->s_flags |= QIB_S_WAIT_DMA;
 271                         goto bail;
 272                 }
 273                 wqe = get_swqe_ptr(qp, qp->s_last);
 274                 qib_send_complete(qp, wqe, qp->s_last != qp->s_acked ?
 275                         IB_WC_SUCCESS : IB_WC_WR_FLUSH_ERR);
 276                 /* will get called again */
 277                 goto done;
 278         }
 279
 280         if (qp->s_flags & (QIB_S_WAIT_RNR | QIB_S_WAIT_ACK))
 281                 goto bail;
 282
 283         if (qib_cmp24(qp->s_psn, qp->s_sending_hpsn) <= 0) {
 284                 if (qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) <= 0) {
 285                         qp->s_flags |= QIB_S_WAIT_PSN;
 286                         goto bail;
 287                 }
 288                 qp->s_sending_psn = qp->s_psn;
 289                 qp->s_sending_hpsn = qp->s_psn - 1;
 290         }
 291
 292         /* header size in 32-bit words LRH+BTH = (8+12)/4. */
 293         hwords = 5;
 294         bth0 = 0;
 295
 296         /* Send a request. */
 297         wqe = get_swqe_ptr(qp, qp->s_cur);
 298         switch (qp->s_state) {
 299         default:
 300                 if (!(ib_qib_state_ops[qp->state] & QIB_PROCESS_NEXT_SEND_OK))
 301                         goto bail;
 302                 /*
 303                  * Resend an old request or start a new one.
 304                  *
 305                  * We keep track of the current SWQE so that
 306                  * we don't reset the "furthest progress" state
 307                  * if we need to back up.
 308                  */
 309                 newreq = 0;
 310                 if (qp->s_cur == qp->s_tail) {
 311                         /* Check if send work queue is empty. */
 312                         if (qp->s_tail == qp->s_head)
 313                                 goto bail;
 314                         /*
 315                          * If a fence is requested, wait for previous
 316                          * RDMA read and atomic operations to finish.
 317                          */
 318                         if ((wqe->wr.send_flags & IB_SEND_FENCE) &&
 319                             qp->s_num_rd_atomic) {
 320                                 qp->s_flags |= QIB_S_WAIT_FENCE;
 321                                 goto bail;
 322                         }
 323                         wqe->psn = qp->s_next_psn;
 324                         newreq = 1;
 325                 }
 326                 /*
 327                  * Note that we have to be careful not to modify the
 328                  * original work request since we may need to resend
 329                  * it.
 330                  */
 331                 len = wqe->length;
 332                 ss = &qp->s_sge;
 333                 bth2 = qp->s_psn & QIB_PSN_MASK;
 334                 switch (wqe->wr.opcode) {
 335                 case IB_WR_SEND:
 336                 case IB_WR_SEND_WITH_IMM:
 337                         /* If no credit, return. */
 338                         if (!(qp->s_flags & QIB_S_UNLIMITED_CREDIT) &&
 339                             qib_cmp24(wqe->ssn, qp->s_lsn + 1) > 0) {
 340                                 qp->s_flags |= QIB_S_WAIT_SSN_CREDIT;
 341                                 goto bail;
 342                         }
 343                         wqe->lpsn = wqe->psn;
 344                         if (len > pmtu) {
 345                                 wqe->lpsn += (len - 1) / pmtu;
 346                                 qp->s_state = OP(SEND_FIRST);
 347                                 len = pmtu;
 348                                 break;
 349                         }
 350                         if (wqe->wr.opcode == IB_WR_SEND)
 351                                 qp->s_state = OP(SEND_ONLY);
 352                         else {
 353                                 qp->s_state = OP(SEND_ONLY_WITH_IMMEDIATE);
 354                                 /* Immediate data comes after the BTH */
 355                                 ohdr->u.imm_data = wqe->wr.ex.imm_data;
 356                                 hwords += 1;
 357                         }
 358                         if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 359                                 bth0 |= IB_BTH_SOLICITED;
 360                         bth2 |= IB_BTH_REQ_ACK;
 361                         if (++qp->s_cur == qp->s_size)
 362                                 qp->s_cur = 0;
 363                         break;
 364
 365                 case IB_WR_RDMA_WRITE:
 366                         if (newreq && !(qp->s_flags & QIB_S_UNLIMITED_CREDIT))
 367                                 qp->s_lsn++;
 368                         /* FALLTHROUGH */
 369                 case IB_WR_RDMA_WRITE_WITH_IMM:
 370                         /* If no credit, return. */
 371                         if (!(qp->s_flags & QIB_S_UNLIMITED_CREDIT) &&
 372                             qib_cmp24(wqe->ssn, qp->s_lsn + 1) > 0) {
 373                                 qp->s_flags |= QIB_S_WAIT_SSN_CREDIT;
 374                                 goto bail;
 375                         }
 376
 377                         ohdr->u.rc.reth.vaddr =
 378                                 cpu_to_be64(wqe->rdma_wr.remote_addr);
 379                         ohdr->u.rc.reth.rkey =
 380                                 cpu_to_be32(wqe->rdma_wr.rkey);
 381                         ohdr->u.rc.reth.length = cpu_to_be32(len);
 382                         hwords += sizeof(struct ib_reth) / sizeof(u32);
 383                         wqe->lpsn = wqe->psn;
 384                         if (len > pmtu) {
 385                                 wqe->lpsn += (len - 1) / pmtu;
 386                                 qp->s_state = OP(RDMA_WRITE_FIRST);
 387                                 len = pmtu;
 388                                 break;
 389                         }
 390                         if (wqe->rdma_wr.wr.opcode == IB_WR_RDMA_WRITE)
 391                                 qp->s_state = OP(RDMA_WRITE_ONLY);
 392                         else {
 393                                 qp->s_state = OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE);
 394                                 /* Immediate data comes after RETH */
 395                                 ohdr->u.rc.imm_data =
 396                                         wqe->rdma_wr.wr.ex.imm_data;
 397                                 hwords += 1;
 398                                 if (wqe->rdma_wr.wr.send_flags & IB_SEND_SOLICITED)
 399                                         bth0 |= IB_BTH_SOLICITED;
 400                         }
 401                         bth2 |= IB_BTH_REQ_ACK;
 402                         if (++qp->s_cur == qp->s_size)
 403                                 qp->s_cur = 0;
 404                         break;
 405
 406                 case IB_WR_RDMA_READ:
 407                         /*
 408                          * Don't allow more operations to be started
 409                          * than the QP limits allow.
 410                          */
 411                         if (newreq) {
 412                                 if (qp->s_num_rd_atomic >=
 413                                     qp->s_max_rd_atomic) {
 414                                         qp->s_flags |= QIB_S_WAIT_RDMAR;
 415                                         goto bail;
 416                                 }
 417                                 qp->s_num_rd_atomic++;
 418                                 if (!(qp->s_flags & QIB_S_UNLIMITED_CREDIT))
 419                                         qp->s_lsn++;
 420                                 /*
 421                                  * Adjust s_next_psn to count the
 422                                  * expected number of responses.
 423                                  */
 424                                 if (len > pmtu)
 425                                         qp->s_next_psn += (len - 1) / pmtu;
 426                                 wqe->lpsn = qp->s_next_psn++;
 427                         }
 428
 429                         ohdr->u.rc.reth.vaddr =
 430                                 cpu_to_be64(wqe->rdma_wr.remote_addr);
 431                         ohdr->u.rc.reth.rkey =
 432                                 cpu_to_be32(wqe->rdma_wr.rkey);
 433                         ohdr->u.rc.reth.length = cpu_to_be32(len);
 434                         qp->s_state = OP(RDMA_READ_REQUEST);
 435                         hwords += sizeof(ohdr->u.rc.reth) / sizeof(u32);
 436                         ss = NULL;
 437                         len = 0;
 438                         bth2 |= IB_BTH_REQ_ACK;
 439                         if (++qp->s_cur == qp->s_size)
 440                                 qp->s_cur = 0;
 441                         break;
 442
 443                 case IB_WR_ATOMIC_CMP_AND_SWP:
 444                 case IB_WR_ATOMIC_FETCH_AND_ADD:
 445                         /*
 446                          * Don't allow more operations to be started
 447                          * than the QP limits allow.
 448                          */
 449                         if (newreq) {
 450                                 if (qp->s_num_rd_atomic >=
 451                                     qp->s_max_rd_atomic) {
 452                                         qp->s_flags |= QIB_S_WAIT_RDMAR;
 453                                         goto bail;
 454                                 }
 455                                 qp->s_num_rd_atomic++;
 456                                 if (!(qp->s_flags & QIB_S_UNLIMITED_CREDIT))
 457                                         qp->s_lsn++;
 458                                 wqe->lpsn = wqe->psn;
 459                         }
 460                         if (wqe->atomic_wr.wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP) {
 461                                 qp->s_state = OP(COMPARE_SWAP);
 462                                 ohdr->u.atomic_eth.swap_data = cpu_to_be64(
 463                                         wqe->atomic_wr.swap);
 464                                 ohdr->u.atomic_eth.compare_data = cpu_to_be64(
 465                                         wqe->atomic_wr.compare_add);
 466                         } else {
 467                                 qp->s_state = OP(FETCH_ADD);
 468                                 ohdr->u.atomic_eth.swap_data = cpu_to_be64(
 469                                         wqe->atomic_wr.compare_add);
 470                                 ohdr->u.atomic_eth.compare_data = 0;
 471                         }
 472                         ohdr->u.atomic_eth.vaddr[0] = cpu_to_be32(
 473                                 wqe->atomic_wr.remote_addr >> 32);
 474                         ohdr->u.atomic_eth.vaddr[1] = cpu_to_be32(
 475                                 wqe->atomic_wr.remote_addr);
 476                         ohdr->u.atomic_eth.rkey = cpu_to_be32(
 477                                 wqe->atomic_wr.rkey);
 478                         hwords += sizeof(struct ib_atomic_eth) / sizeof(u32);
 479                         ss = NULL;
 480                         len = 0;
 481                         bth2 |= IB_BTH_REQ_ACK;
 482                         if (++qp->s_cur == qp->s_size)
 483                                 qp->s_cur = 0;
 484                         break;
 485
 486                 default:
 487                         goto bail;
 488                 }
 489                 qp->s_sge.sge = wqe->sg_list[0];
 490                 qp->s_sge.sg_list = wqe->sg_list + 1;
 491                 qp->s_sge.num_sge = wqe->wr.num_sge;
 492                 qp->s_sge.total_len = wqe->length;
 493                 qp->s_len = wqe->length;
 494                 if (newreq) {
 495                         qp->s_tail++;
 496                         if (qp->s_tail >= qp->s_size)
 497                                 qp->s_tail = 0;
 498                 }
 499                 if (wqe->wr.opcode == IB_WR_RDMA_READ)
 500                         qp->s_psn = wqe->lpsn + 1;
 501                 else {
 502                         qp->s_psn++;
 503                         if (qib_cmp24(qp->s_psn, qp->s_next_psn) > 0)
 504                                 qp->s_next_psn = qp->s_psn;
 505                 }
 506                 break;
 507
 508         case OP(RDMA_READ_RESPONSE_FIRST):
 509                 /*
 510                  * qp->s_state is normally set to the opcode of the
 511                  * last packet constructed for new requests and therefore
 512                  * is never set to RDMA read response.
 513                  * RDMA_READ_RESPONSE_FIRST is used by the ACK processing
 514                  * thread to indicate a SEND needs to be restarted from an
 515                  * earlier PSN without interferring with the sending thread.
 516                  * See qib_restart_rc().
 517                  */
 518                 qp->s_len = restart_sge(&qp->s_sge, wqe, qp->s_psn, pmtu);
 519                 /* FALLTHROUGH */
 520         case OP(SEND_FIRST):
 521                 qp->s_state = OP(SEND_MIDDLE);
 522                 /* FALLTHROUGH */
 523         case OP(SEND_MIDDLE):
 524                 bth2 = qp->s_psn++ & QIB_PSN_MASK;
 525                 if (qib_cmp24(qp->s_psn, qp->s_next_psn) > 0)
 526                         qp->s_next_psn = qp->s_psn;
 527                 ss = &qp->s_sge;
 528                 len = qp->s_len;
 529                 if (len > pmtu) {
 530                         len = pmtu;
 531                         break;
 532                 }
 533                 if (wqe->wr.opcode == IB_WR_SEND)
 534                         qp->s_state = OP(SEND_LAST);
 535                 else {
 536                         qp->s_state = OP(SEND_LAST_WITH_IMMEDIATE);
 537                         /* Immediate data comes after the BTH */
 538                         ohdr->u.imm_data = wqe->wr.ex.imm_data;
 539                         hwords += 1;
 540                 }
 541                 if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 542                         bth0 |= IB_BTH_SOLICITED;
 543                 bth2 |= IB_BTH_REQ_ACK;
 544                 qp->s_cur++;
 545                 if (qp->s_cur >= qp->s_size)
 546                         qp->s_cur = 0;
 547                 break;
 548
 549         case OP(RDMA_READ_RESPONSE_LAST):
 550                 /*
 551                  * qp->s_state is normally set to the opcode of the
 552                  * last packet constructed for new requests and therefore
 553                  * is never set to RDMA read response.
 554                  * RDMA_READ_RESPONSE_LAST is used by the ACK processing
 555                  * thread to indicate a RDMA write needs to be restarted from
 556                  * an earlier PSN without interferring with the sending thread.
 557                  * See qib_restart_rc().
 558                  */
 559                 qp->s_len = restart_sge(&qp->s_sge, wqe, qp->s_psn, pmtu);
 560                 /* FALLTHROUGH */
 561         case OP(RDMA_WRITE_FIRST):
 562                 qp->s_state = OP(RDMA_WRITE_MIDDLE);
 563                 /* FALLTHROUGH */
 564         case OP(RDMA_WRITE_MIDDLE):
 565                 bth2 = qp->s_psn++ & QIB_PSN_MASK;
 566                 if (qib_cmp24(qp->s_psn, qp->s_next_psn) > 0)
 567                         qp->s_next_psn = qp->s_psn;
 568                 ss = &qp->s_sge;
 569                 len = qp->s_len;
 570                 if (len > pmtu) {
 571                         len = pmtu;
 572                         break;
 573                 }
 574                 if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
 575                         qp->s_state = OP(RDMA_WRITE_LAST);
 576                 else {
 577                         qp->s_state = OP(RDMA_WRITE_LAST_WITH_IMMEDIATE);
 578                         /* Immediate data comes after the BTH */
 579                         ohdr->u.imm_data = wqe->wr.ex.imm_data;
 580                         hwords += 1;
 581                         if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 582                                 bth0 |= IB_BTH_SOLICITED;
 583                 }
 584                 bth2 |= IB_BTH_REQ_ACK;
 585                 qp->s_cur++;
 586                 if (qp->s_cur >= qp->s_size)
 587                         qp->s_cur = 0;
 588                 break;
 589
 590         case OP(RDMA_READ_RESPONSE_MIDDLE):
 591                 /*
 592                  * qp->s_state is normally set to the opcode of the
 593                  * last packet constructed for new requests and therefore
 594                  * is never set to RDMA read response.
 595                  * RDMA_READ_RESPONSE_MIDDLE is used by the ACK processing
 596                  * thread to indicate a RDMA read needs to be restarted from
 597                  * an earlier PSN without interferring with the sending thread.
 598                  * See qib_restart_rc().
 599                  */
 600                 len = ((qp->s_psn - wqe->psn) & QIB_PSN_MASK) * pmtu;
 601                 ohdr->u.rc.reth.vaddr =
 602                         cpu_to_be64(wqe->rdma_wr.remote_addr + len);
 603                 ohdr->u.rc.reth.rkey =
 604                         cpu_to_be32(wqe->rdma_wr.rkey);
 605                 ohdr->u.rc.reth.length = cpu_to_be32(wqe->length - len);
 606                 qp->s_state = OP(RDMA_READ_REQUEST);
 607                 hwords += sizeof(ohdr->u.rc.reth) / sizeof(u32);
 608                 bth2 = (qp->s_psn & QIB_PSN_MASK) | IB_BTH_REQ_ACK;
 609                 qp->s_psn = wqe->lpsn + 1;
 610                 ss = NULL;
 611                 len = 0;
 612                 qp->s_cur++;
 613                 if (qp->s_cur == qp->s_size)
 614                         qp->s_cur = 0;
 615                 break;
 616         }
 617         qp->s_sending_hpsn = bth2;
 618         delta = (((int) bth2 - (int) wqe->psn) << 8) >> 8;
 619         if (delta && delta % QIB_PSN_CREDIT == 0)
 620                 bth2 |= IB_BTH_REQ_ACK;
 621         if (qp->s_flags & QIB_S_SEND_ONE) {
 622                 qp->s_flags &= ~QIB_S_SEND_ONE;
 623                 qp->s_flags |= QIB_S_WAIT_ACK;
 624                 bth2 |= IB_BTH_REQ_ACK;
 625         }
 626         qp->s_len -= len;
 627         qp->s_hdrwords = hwords;
 628         qp->s_cur_sge = ss;
 629         qp->s_cur_size = len;
 630         qib_make_ruc_header(qp, ohdr, bth0 | (qp->s_state << 24), bth2);
 631 done:
 632         ret = 1;
 633         goto unlock;
 634
 635 bail:
 636         qp->s_flags &= ~QIB_S_BUSY;
 637 unlock:
 638         spin_unlock_irqrestore(&qp->s_lock, flags);
 639         return ret;
 640 }
 641
 642 /**
 643  * qib_send_rc_ack - Construct an ACK packet and send it
 644  * @qp: a pointer to the QP
 645  *
 646  * This is called from qib_rc_rcv() and qib_kreceive().
 647  * Note that RDMA reads and atomics are handled in the
 648  * send side QP state and tasklet.
 649  */
 650 void qib_send_rc_ack(struct qib_qp *qp)
 651 {
 652         struct qib_devdata *dd = dd_from_ibdev(qp->ibqp.device);
 653         struct qib_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
 654         struct qib_pportdata *ppd = ppd_from_ibp(ibp);
 655         u64 pbc;
 656         u16 lrh0;
 657         u32 bth0;
 658         u32 hwords;
 659         u32 pbufn;
 660         u32 __iomem *piobuf;
 661         struct qib_ib_header hdr;
 662         struct qib_other_headers *ohdr;
 663         u32 control;
 664         unsigned long flags;
 665
 666         spin_lock_irqsave(&qp->s_lock, flags);
 667
 668         if (!(ib_qib_state_ops[qp->state] & QIB_PROCESS_RECV_OK))
 669                 goto unlock;
 670
 671         /* Don't send ACK or NAK if a RDMA read or atomic is pending. */
 672         if ((qp->s_flags & QIB_S_RESP_PENDING) || qp->s_rdma_ack_cnt)
 673                 goto queue_ack;
 674
 675         /* Construct the header with s_lock held so APM doesn't change it. */
 676         ohdr = &hdr.u.oth;
 677         lrh0 = QIB_LRH_BTH;
 678         /* header size in 32-bit words LRH+BTH+AETH = (8+12+4)/4. */
 679         hwords = 6;
 680         if (unlikely(qp->remote_ah_attr.ah_flags & IB_AH_GRH)) {
 681                 hwords += qib_make_grh(ibp, &hdr.u.l.grh,
 682                                        &qp->remote_ah_attr.grh, hwords, 0);
 683                 ohdr = &hdr.u.l.oth;
 684                 lrh0 = QIB_LRH_GRH;
 685         }
 686         /* read pkey_index w/o lock (its atomic) */
 687         bth0 = qib_get_pkey(ibp, qp->s_pkey_index) | (OP(ACKNOWLEDGE) << 24);
 688         if (qp->s_mig_state == IB_MIG_MIGRATED)
 689                 bth0 |= IB_BTH_MIG_REQ;
 690         if (qp->r_nak_state)
 691                 ohdr->u.aeth = cpu_to_be32((qp->r_msn & QIB_MSN_MASK) |
 692                                             (qp->r_nak_state <<
 693                                              QIB_AETH_CREDIT_SHIFT));
 694         else
 695                 ohdr->u.aeth = qib_compute_aeth(qp);
 696         lrh0 |= ibp->sl_to_vl[qp->remote_ah_attr.sl] << 12 |
 697                 qp->remote_ah_attr.sl << 4;
 698         hdr.lrh[0] = cpu_to_be16(lrh0);
 699         hdr.lrh[1] = cpu_to_be16(qp->remote_ah_attr.dlid);
 700         hdr.lrh[2] = cpu_to_be16(hwords + SIZE_OF_CRC);
 701         hdr.lrh[3] = cpu_to_be16(ppd->lid | qp->remote_ah_attr.src_path_bits);
 702         ohdr->bth[0] = cpu_to_be32(bth0);
 703         ohdr->bth[1] = cpu_to_be32(qp->remote_qpn);
 704         ohdr->bth[2] = cpu_to_be32(qp->r_ack_psn & QIB_PSN_MASK);
 705
 706         spin_unlock_irqrestore(&qp->s_lock, flags);
 707
 708         /* Don't try to send ACKs if the link isn't ACTIVE */
 709         if (!(ppd->lflags & QIBL_LINKACTIVE))
 710                 goto done;
 711
 712         control = dd->f_setpbc_control(ppd, hwords + SIZE_OF_CRC,
 713                                        qp->s_srate, lrh0 >> 12);
 714         /* length is + 1 for the control dword */
 715         pbc = ((u64) control << 32) | (hwords + 1);
 716
 717         piobuf = dd->f_getsendbuf(ppd, pbc, &pbufn);
 718         if (!piobuf) {
 719                 /*
 720                  * We are out of PIO buffers at the moment.
 721                  * Pass responsibility for sending the ACK to the
 722                  * send tasklet so that when a PIO buffer becomes
 723                  * available, the ACK is sent ahead of other outgoing
 724                  * packets.
 725                  */
 726                 spin_lock_irqsave(&qp->s_lock, flags);
 727                 goto queue_ack;
 728         }
 729
 730         /*
 731          * Write the pbc.
 732          * We have to flush after the PBC for correctness
 733          * on some cpus or WC buffer can be written out of order.
 734          */
 735         writeq(pbc, piobuf);
 736
 737         if (dd->flags & QIB_PIO_FLUSH_WC) {
 738                 u32 *hdrp = (u32 *) &hdr;
 739
 740                 qib_flush_wc();
 741                 qib_pio_copy(piobuf + 2, hdrp, hwords - 1);
 742                 qib_flush_wc();
 743                 __raw_writel(hdrp[hwords - 1], piobuf + hwords + 1);
 744         } else
 745                 qib_pio_copy(piobuf + 2, (u32 *) &hdr, hwords);
 746
 747         if (dd->flags & QIB_USE_SPCL_TRIG) {
 748                 u32 spcl_off = (pbufn >= dd->piobcnt2k) ? 2047 : 1023;
 749
 750                 qib_flush_wc();
 751                 __raw_writel(0xaebecede, piobuf + spcl_off);
 752         }
 753
 754         qib_flush_wc();
 755         qib_sendbuf_done(dd, pbufn);
 756
 757         this_cpu_inc(ibp->pmastats->n_unicast_xmit);
 758         goto done;
 759
 760 queue_ack:
 761         if (ib_qib_state_ops[qp->state] & QIB_PROCESS_RECV_OK) {
 762                 ibp->n_rc_qacks++;
 763                 qp->s_flags |= QIB_S_ACK_PENDING | QIB_S_RESP_PENDING;
 764                 qp->s_nak_state = qp->r_nak_state;
 765                 qp->s_ack_psn = qp->r_ack_psn;
 766
 767                 /* Schedule the send tasklet. */
 768                 qib_schedule_send(qp);
 769         }
 770 unlock:
 771         spin_unlock_irqrestore(&qp->s_lock, flags);
 772 done:
 773         return;
 774 }
 775
 776 /**
 777  * reset_psn - reset the QP state to send starting from PSN
 778  * @qp: the QP
 779  * @psn: the packet sequence number to restart at
 780  *
 781  * This is called from qib_rc_rcv() to process an incoming RC ACK
 782  * for the given QP.
 783  * Called at interrupt level with the QP s_lock held.
 784  */
 785 static void reset_psn(struct qib_qp *qp, u32 psn)
 786 {
 787         u32 n = qp->s_acked;
 788         struct qib_swqe *wqe = get_swqe_ptr(qp, n);
 789         u32 opcode;
 790
 791         qp->s_cur = n;
 792
 793         /*
 794          * If we are starting the request from the beginning,
 795          * let the normal send code handle initialization.
 796          */
 797         if (qib_cmp24(psn, wqe->psn) <= 0) {
 798                 qp->s_state = OP(SEND_LAST);
 799                 goto done;
 800         }
 801
 802         /* Find the work request opcode corresponding to the given PSN. */
 803         opcode = wqe->wr.opcode;
 804         for (;;) {
 805                 int diff;
 806
 807                 if (++n == qp->s_size)
 808                         n = 0;
 809                 if (n == qp->s_tail)
 810                         break;
 811                 wqe = get_swqe_ptr(qp, n);
 812                 diff = qib_cmp24(psn, wqe->psn);
 813                 if (diff < 0)
 814                         break;
 815                 qp->s_cur = n;
 816                 /*
 817                  * If we are starting the request from the beginning,
 818                  * let the normal send code handle initialization.
 819                  */
 820                 if (diff == 0) {
 821                         qp->s_state = OP(SEND_LAST);
 822                         goto done;
 823                 }
 824                 opcode = wqe->wr.opcode;
 825         }
 826
 827         /*
 828          * Set the state to restart in the middle of a request.
 829          * Don't change the s_sge, s_cur_sge, or s_cur_size.
 830          * See qib_make_rc_req().
 831          */
 832         switch (opcode) {
 833         case IB_WR_SEND:
 834         case IB_WR_SEND_WITH_IMM:
 835                 qp->s_state = OP(RDMA_READ_RESPONSE_FIRST);
 836                 break;
 837
 838         case IB_WR_RDMA_WRITE:
 839         case IB_WR_RDMA_WRITE_WITH_IMM:
 840                 qp->s_state = OP(RDMA_READ_RESPONSE_LAST);
 841                 break;
 842
 843         case IB_WR_RDMA_READ:
 844                 qp->s_state = OP(RDMA_READ_RESPONSE_MIDDLE);
 845                 break;
 846
 847         default:
 848                 /*
 849                  * This case shouldn't happen since its only
 850                  * one PSN per req.
 851                  */
 852                 qp->s_state = OP(SEND_LAST);
 853         }
 854 done:
 855         qp->s_psn = psn;
 856         /*
 857          * Set QIB_S_WAIT_PSN as qib_rc_complete() may start the timer
 858          * asynchronously before the send tasklet can get scheduled.
 859          * Doing it in qib_make_rc_req() is too late.
 860          */
 861         if ((qib_cmp24(qp->s_psn, qp->s_sending_hpsn) <= 0) &&
 862             (qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) <= 0))
 863                 qp->s_flags |= QIB_S_WAIT_PSN;
 864 }
 865
 866 /*
 867  * Back up requester to resend the last un-ACKed request.
 868  * The QP r_lock and s_lock should be held and interrupts disabled.
 869  */
 870 static void qib_restart_rc(struct qib_qp *qp, u32 psn, int wait)
 871 {
 872         struct qib_swqe *wqe = get_swqe_ptr(qp, qp->s_acked);
 873         struct qib_ibport *ibp;
 874
 875         if (qp->s_retry == 0) {
 876                 if (qp->s_mig_state == IB_MIG_ARMED) {
 877                         qib_migrate_qp(qp);
 878                         qp->s_retry = qp->s_retry_cnt;
 879                 } else if (qp->s_last == qp->s_acked) {
 880                         qib_send_complete(qp, wqe, IB_WC_RETRY_EXC_ERR);
 881                         qib_error_qp(qp, IB_WC_WR_FLUSH_ERR);
 882                         return;
 883                 } else /* XXX need to handle delayed completion */
 884                         return;
 885         } else
 886                 qp->s_retry--;
 887
 888         ibp = to_iport(qp->ibqp.device, qp->port_num);
 889         if (wqe->wr.opcode == IB_WR_RDMA_READ)
 890                 ibp->n_rc_resends++;
 891         else
 892                 ibp->n_rc_resends += (qp->s_psn - psn) & QIB_PSN_MASK;
 893
 894         qp->s_flags &= ~(QIB_S_WAIT_FENCE | QIB_S_WAIT_RDMAR |
 895                          QIB_S_WAIT_SSN_CREDIT | QIB_S_WAIT_PSN |
 896                          QIB_S_WAIT_ACK);
 897         if (wait)
 898                 qp->s_flags |= QIB_S_SEND_ONE;
 899         reset_psn(qp, psn);
 900 }
 901
 902 /*
 903  * This is called from s_timer for missing responses.
 904  */
 905 static void rc_timeout(unsigned long arg)
 906 {
 907         struct qib_qp *qp = (struct qib_qp *)arg;
 908         struct qib_ibport *ibp;
 909         unsigned long flags;
 910
 911         spin_lock_irqsave(&qp->r_lock, flags);
 912         spin_lock(&qp->s_lock);
 913         if (qp->s_flags & QIB_S_TIMER) {
 914                 ibp = to_iport(qp->ibqp.device, qp->port_num);
 915                 ibp->n_rc_timeouts++;
 916                 qp->s_flags &= ~QIB_S_TIMER;
 917                 del_timer(&qp->s_timer);
 918                 qib_restart_rc(qp, qp->s_last_psn + 1, 1);
 919                 qib_schedule_send(qp);
 920         }
 921         spin_unlock(&qp->s_lock);
 922         spin_unlock_irqrestore(&qp->r_lock, flags);
 923 }
 924
 925 /*
 926  * This is called from s_timer for RNR timeouts.
 927  */
 928 void qib_rc_rnr_retry(unsigned long arg)
 929 {
 930         struct qib_qp *qp = (struct qib_qp *)arg;
 931         unsigned long flags;
 932
 933         spin_lock_irqsave(&qp->s_lock, flags);
 934         if (qp->s_flags & QIB_S_WAIT_RNR) {
 935                 qp->s_flags &= ~QIB_S_WAIT_RNR;
 936                 del_timer(&qp->s_timer);
 937                 qib_schedule_send(qp);
 938         }
 939         spin_unlock_irqrestore(&qp->s_lock, flags);
 940 }
 941
 942 /*
 943  * Set qp->s_sending_psn to the next PSN after the given one.
 944  * This would be psn+1 except when RDMA reads are present.
 945  */
 946 static void reset_sending_psn(struct qib_qp *qp, u32 psn)
 947 {
 948         struct qib_swqe *wqe;
 949         u32 n = qp->s_last;
 950
 951         /* Find the work request corresponding to the given PSN. */
 952         for (;;) {
 953                 wqe = get_swqe_ptr(qp, n);
 954                 if (qib_cmp24(psn, wqe->lpsn) <= 0) {
 955                         if (wqe->wr.opcode == IB_WR_RDMA_READ)
 956                                 qp->s_sending_psn = wqe->lpsn + 1;
 957                         else
 958                                 qp->s_sending_psn = psn + 1;
 959                         break;
 960                 }
 961                 if (++n == qp->s_size)
 962                         n = 0;
 963                 if (n == qp->s_tail)
 964                         break;
 965         }
 966 }
 967
 968 /*
 969  * This should be called with the QP s_lock held and interrupts disabled.
 970  */
 971 void qib_rc_send_complete(struct qib_qp *qp, struct qib_ib_header *hdr)
 972 {
 973         struct qib_other_headers *ohdr;
 974         struct qib_swqe *wqe;
 975         struct ib_wc wc;
 976         unsigned i;
 977         u32 opcode;
 978         u32 psn;
 979
 980         if (!(ib_qib_state_ops[qp->state] & QIB_PROCESS_OR_FLUSH_SEND))
 981                 return;
 982
 983         /* Find out where the BTH is */
 984         if ((be16_to_cpu(hdr->lrh[0]) & 3) == QIB_LRH_BTH)
 985                 ohdr = &hdr->u.oth;
 986         else
 987                 ohdr = &hdr->u.l.oth;
 988
 989         opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
 990         if (opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
 991             opcode <= OP(ATOMIC_ACKNOWLEDGE)) {
 992                 WARN_ON(!qp->s_rdma_ack_cnt);
 993                 qp->s_rdma_ack_cnt--;
 994                 return;
 995         }
 996
 997         psn = be32_to_cpu(ohdr->bth[2]);
 998         reset_sending_psn(qp, psn);
 999
1000         /*
1001          * Start timer after a packet requesting an ACK has been sent and
1002          * there are still requests that haven't been acked.
1003          */
1004         if ((psn & IB_BTH_REQ_ACK) && qp->s_acked != qp->s_tail &&
1005             !(qp->s_flags & (QIB_S_TIMER | QIB_S_WAIT_RNR | QIB_S_WAIT_PSN)) &&
1006             (ib_qib_state_ops[qp->state] & QIB_PROCESS_RECV_OK))
1007                 start_timer(qp);
1008
1009         while (qp->s_last != qp->s_acked) {
1010                 wqe = get_swqe_ptr(qp, qp->s_last);
1011                 if (qib_cmp24(wqe->lpsn, qp->s_sending_psn) >= 0 &&
1012                     qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) <= 0)
1013                         break;
1014                 for (i = 0; i < wqe->wr.num_sge; i++) {
1015                         struct qib_sge *sge = &wqe->sg_list[i];
1016
1017                         qib_put_mr(sge->mr);
1018                 }
1019                 /* Post a send completion queue entry if requested. */
1020                 if (!(qp->s_flags & QIB_S_SIGNAL_REQ_WR) ||
1021                     (wqe->wr.send_flags & IB_SEND_SIGNALED)) {
1022                         memset(&wc, 0, sizeof(wc));
1023                         wc.wr_id = wqe->wr.wr_id;
1024                         wc.status = IB_WC_SUCCESS;
1025                         wc.opcode = ib_qib_wc_opcode[wqe->wr.opcode];
1026                         wc.byte_len = wqe->length;
1027                         wc.qp = &qp->ibqp;
1028                         qib_cq_enter(to_icq(qp->ibqp.send_cq), &wc, 0);
1029                 }
1030                 if (++qp->s_last >= qp->s_size)
1031                         qp->s_last = 0;
1032         }
1033         /*
1034          * If we were waiting for sends to complete before resending,
1035          * and they are now complete, restart sending.
1036          */
1037         if (qp->s_flags & QIB_S_WAIT_PSN &&
1038             qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) > 0) {
1039                 qp->s_flags &= ~QIB_S_WAIT_PSN;
1040                 qp->s_sending_psn = qp->s_psn;
1041                 qp->s_sending_hpsn = qp->s_psn - 1;
1042                 qib_schedule_send(qp);
1043         }
1044 }
1045
1046 static inline void update_last_psn(struct qib_qp *qp, u32 psn)
1047 {
1048         qp->s_last_psn = psn;
1049 }
1050
1051 /*
1052  * Generate a SWQE completion.
1053  * This is similar to qib_send_complete but has to check to be sure
1054  * that the SGEs are not being referenced if the SWQE is being resent.
1055  */
1056 static struct qib_swqe *do_rc_completion(struct qib_qp *qp,
1057                                          struct qib_swqe *wqe,
1058                                          struct qib_ibport *ibp)
1059 {
1060         struct ib_wc wc;
1061         unsigned i;
1062
1063         /*
1064          * Don't decrement refcount and don't generate a
1065          * completion if the SWQE is being resent until the send
1066          * is finished.
1067          */
1068         if (qib_cmp24(wqe->lpsn, qp->s_sending_psn) < 0 ||
1069             qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) > 0) {
1070                 for (i = 0; i < wqe->wr.num_sge; i++) {
1071                         struct qib_sge *sge = &wqe->sg_list[i];
1072
1073                         qib_put_mr(sge->mr);
1074                 }
1075                 /* Post a send completion queue entry if requested. */
1076                 if (!(qp->s_flags & QIB_S_SIGNAL_REQ_WR) ||
1077                     (wqe->wr.send_flags & IB_SEND_SIGNALED)) {
1078                         memset(&wc, 0, sizeof(wc));
1079                         wc.wr_id = wqe->wr.wr_id;
1080                         wc.status = IB_WC_SUCCESS;
1081                         wc.opcode = ib_qib_wc_opcode[wqe->wr.opcode];
1082                         wc.byte_len = wqe->length;
1083                         wc.qp = &qp->ibqp;
1084                         qib_cq_enter(to_icq(qp->ibqp.send_cq), &wc, 0);
1085                 }
1086                 if (++qp->s_last >= qp->s_size)
1087                         qp->s_last = 0;
1088         } else
1089                 ibp->n_rc_delayed_comp++;
1090
1091         qp->s_retry = qp->s_retry_cnt;
1092         update_last_psn(qp, wqe->lpsn);
1093
1094         /*
1095          * If we are completing a request which is in the process of
1096          * being resent, we can stop resending it since we know the
1097          * responder has already seen it.
1098          */
1099         if (qp->s_acked == qp->s_cur) {
1100                 if (++qp->s_cur >= qp->s_size)
1101                         qp->s_cur = 0;
1102                 qp->s_acked = qp->s_cur;
1103                 wqe = get_swqe_ptr(qp, qp->s_cur);
1104                 if (qp->s_acked != qp->s_tail) {
1105                         qp->s_state = OP(SEND_LAST);
1106                         qp->s_psn = wqe->psn;
1107                 }
1108         } else {
1109                 if (++qp->s_acked >= qp->s_size)
1110                         qp->s_acked = 0;
1111                 if (qp->state == IB_QPS_SQD && qp->s_acked == qp->s_cur)
1112                         qp->s_draining = 0;
1113                 wqe = get_swqe_ptr(qp, qp->s_acked);
1114         }
1115         return wqe;
1116 }
1117
1118 /**
1119  * do_rc_ack - process an incoming RC ACK
1120  * @qp: the QP the ACK came in on
1121  * @psn: the packet sequence number of the ACK
1122  * @opcode: the opcode of the request that resulted in the ACK
1123  *
1124  * This is called from qib_rc_rcv_resp() to process an incoming RC ACK
1125  * for the given QP.
1126  * Called at interrupt level with the QP s_lock held.
1127  * Returns 1 if OK, 0 if current operation should be aborted (NAK).
1128  */
1129 static int do_rc_ack(struct qib_qp *qp, u32 aeth, u32 psn, int opcode,
1130                      u64 val, struct qib_ctxtdata *rcd)
1131 {
1132         struct qib_ibport *ibp;
1133         enum ib_wc_status status;
1134         struct qib_swqe *wqe;
1135         int ret = 0;
1136         u32 ack_psn;
1137         int diff;
1138
1139         /* Remove QP from retry timer */
1140         if (qp->s_flags & (QIB_S_TIMER | QIB_S_WAIT_RNR)) {
1141                 qp->s_flags &= ~(QIB_S_TIMER | QIB_S_WAIT_RNR);
1142                 del_timer(&qp->s_timer);
1143         }
1144
1145         /*
1146          * Note that NAKs implicitly ACK outstanding SEND and RDMA write
1147          * requests and implicitly NAK RDMA read and atomic requests issued
1148          * before the NAK'ed request.  The MSN won't include the NAK'ed
1149          * request but will include an ACK'ed request(s).
1150          */
1151         ack_psn = psn;
1152         if (aeth >> 29)
1153                 ack_psn--;
1154         wqe = get_swqe_ptr(qp, qp->s_acked);
1155         ibp = to_iport(qp->ibqp.device, qp->port_num);
1156
1157         /*
1158          * The MSN might be for a later WQE than the PSN indicates so
1159          * only complete WQEs that the PSN finishes.
1160          */
1161         while ((diff = qib_cmp24(ack_psn, wqe->lpsn)) >= 0) {
1162                 /*
1163                  * RDMA_READ_RESPONSE_ONLY is a special case since
1164                  * we want to generate completion events for everything
1165                  * before the RDMA read, copy the data, then generate
1166                  * the completion for the read.
1167                  */
1168                 if (wqe->wr.opcode == IB_WR_RDMA_READ &&
1169                     opcode == OP(RDMA_READ_RESPONSE_ONLY) &&
1170                     diff == 0) {
1171                         ret = 1;
1172                         goto bail;
1173                 }
1174                 /*
1175                  * If this request is a RDMA read or atomic, and the ACK is
1176                  * for a later operation, this ACK NAKs the RDMA read or
1177                  * atomic.  In other words, only a RDMA_READ_LAST or ONLY
1178                  * can ACK a RDMA read and likewise for atomic ops.  Note
1179                  * that the NAK case can only happen if relaxed ordering is
1180                  * used and requests are sent after an RDMA read or atomic
1181                  * is sent but before the response is received.
1182                  */
1183                 if ((wqe->wr.opcode == IB_WR_RDMA_READ &&
1184                      (opcode != OP(RDMA_READ_RESPONSE_LAST) || diff != 0)) ||
1185                     ((wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1186                       wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) &&
1187                      (opcode != OP(ATOMIC_ACKNOWLEDGE) || diff != 0))) {
1188                         /* Retry this request. */
1189                         if (!(qp->r_flags & QIB_R_RDMAR_SEQ)) {
1190                                 qp->r_flags |= QIB_R_RDMAR_SEQ;
1191                                 qib_restart_rc(qp, qp->s_last_psn + 1, 0);
1192                                 if (list_empty(&qp->rspwait)) {
1193                                         qp->r_flags |= QIB_R_RSP_SEND;
1194                                         atomic_inc(&qp->refcount);
1195                                         list_add_tail(&qp->rspwait,
1196                                                       &rcd->qp_wait_list);
1197                                 }
1198                         }
1199                         /*
1200                          * No need to process the ACK/NAK since we are
1201                          * restarting an earlier request.
1202                          */
1203                         goto bail;
1204                 }
1205                 if (wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1206                     wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) {
1207                         u64 *vaddr = wqe->sg_list[0].vaddr;
1208                         *vaddr = val;
1209                 }
1210                 if (qp->s_num_rd_atomic &&
1211                     (wqe->wr.opcode == IB_WR_RDMA_READ ||
1212                      wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1213                      wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)) {
1214                         qp->s_num_rd_atomic--;
1215                         /* Restart sending task if fence is complete */
1216                         if ((qp->s_flags & QIB_S_WAIT_FENCE) &&
1217                             !qp->s_num_rd_atomic) {
1218                                 qp->s_flags &= ~(QIB_S_WAIT_FENCE |
1219                                                  QIB_S_WAIT_ACK);
1220                                 qib_schedule_send(qp);
1221                         } else if (qp->s_flags & QIB_S_WAIT_RDMAR) {
1222                                 qp->s_flags &= ~(QIB_S_WAIT_RDMAR |
1223                                                  QIB_S_WAIT_ACK);
1224                                 qib_schedule_send(qp);
1225                         }
1226                 }
1227                 wqe = do_rc_completion(qp, wqe, ibp);
1228                 if (qp->s_acked == qp->s_tail)
1229                         break;
1230         }
1231
1232         switch (aeth >> 29) {
1233         case 0:         /* ACK */
1234                 ibp->n_rc_acks++;
1235                 if (qp->s_acked != qp->s_tail) {
1236                         /*
1237                          * We are expecting more ACKs so
1238                          * reset the retransmit timer.
1239                          */
1240                         start_timer(qp);
1241                         /*
1242                          * We can stop resending the earlier packets and
1243                          * continue with the next packet the receiver wants.
1244                          */
1245                         if (qib_cmp24(qp->s_psn, psn) <= 0)
1246                                 reset_psn(qp, psn + 1);
1247                 } else if (qib_cmp24(qp->s_psn, psn) <= 0) {
1248                         qp->s_state = OP(SEND_LAST);
1249                         qp->s_psn = psn + 1;
1250                 }
1251                 if (qp->s_flags & QIB_S_WAIT_ACK) {
1252                         qp->s_flags &= ~QIB_S_WAIT_ACK;
1253                         qib_schedule_send(qp);
1254                 }
1255                 qib_get_credit(qp, aeth);
1256                 qp->s_rnr_retry = qp->s_rnr_retry_cnt;
1257                 qp->s_retry = qp->s_retry_cnt;
1258                 update_last_psn(qp, psn);
1259                 ret = 1;
1260                 goto bail;
1261
1262         case 1:         /* RNR NAK */
1263                 ibp->n_rnr_naks++;
1264                 if (qp->s_acked == qp->s_tail)
1265                         goto bail;
1266                 if (qp->s_flags & QIB_S_WAIT_RNR)
1267                         goto bail;
1268                 if (qp->s_rnr_retry == 0) {
1269                         status = IB_WC_RNR_RETRY_EXC_ERR;
1270                         goto class_b;
1271                 }
1272                 if (qp->s_rnr_retry_cnt < 7)
1273                         qp->s_rnr_retry--;
1274
1275                 /* The last valid PSN is the previous PSN. */
1276                 update_last_psn(qp, psn - 1);
1277
1278                 ibp->n_rc_resends += (qp->s_psn - psn) & QIB_PSN_MASK;
1279
1280                 reset_psn(qp, psn);
1281
1282                 qp->s_flags &= ~(QIB_S_WAIT_SSN_CREDIT | QIB_S_WAIT_ACK);
1283                 qp->s_flags |= QIB_S_WAIT_RNR;
1284                 qp->s_timer.function = qib_rc_rnr_retry;
1285                 qp->s_timer.expires = jiffies + usecs_to_jiffies(
1286                         ib_qib_rnr_table[(aeth >> QIB_AETH_CREDIT_SHIFT) &
1287                                            QIB_AETH_CREDIT_MASK]);
1288                 add_timer(&qp->s_timer);
1289                 goto bail;
1290
1291         case 3:         /* NAK */
1292                 if (qp->s_acked == qp->s_tail)
1293                         goto bail;
1294                 /* The last valid PSN is the previous PSN. */
1295                 update_last_psn(qp, psn - 1);
1296                 switch ((aeth >> QIB_AETH_CREDIT_SHIFT) &
1297                         QIB_AETH_CREDIT_MASK) {
1298                 case 0: /* PSN sequence error */
1299                         ibp->n_seq_naks++;
1300                         /*
1301                          * Back up to the responder's expected PSN.
1302                          * Note that we might get a NAK in the middle of an
1303                          * RDMA READ response which terminates the RDMA
1304                          * READ.
1305                          */
1306                         qib_restart_rc(qp, psn, 0);
1307                         qib_schedule_send(qp);
1308                         break;
1309
1310                 case 1: /* Invalid Request */
1311                         status = IB_WC_REM_INV_REQ_ERR;
1312                         ibp->n_other_naks++;
1313                         goto class_b;
1314
1315                 case 2: /* Remote Access Error */
1316                         status = IB_WC_REM_ACCESS_ERR;
1317                         ibp->n_other_naks++;
1318                         goto class_b;
1319
1320                 case 3: /* Remote Operation Error */
1321                         status = IB_WC_REM_OP_ERR;
1322                         ibp->n_other_naks++;
1323 class_b:
1324                         if (qp->s_last == qp->s_acked) {
1325                                 qib_send_complete(qp, wqe, status);
1326                                 qib_error_qp(qp, IB_WC_WR_FLUSH_ERR);
1327                         }
1328                         break;
1329
1330                 default:
1331                         /* Ignore other reserved NAK error codes */
1332                         goto reserved;
1333                 }
1334                 qp->s_retry = qp->s_retry_cnt;
1335                 qp->s_rnr_retry = qp->s_rnr_retry_cnt;
1336                 goto bail;
1337
1338         default:                /* 2: reserved */
1339 reserved:
1340                 /* Ignore reserved NAK codes. */
1341                 goto bail;
1342         }
1343
1344 bail:
1345         return ret;
1346 }
1347
1348 /*
1349  * We have seen an out of sequence RDMA read middle or last packet.
1350  * This ACKs SENDs and RDMA writes up to the first RDMA read or atomic SWQE.
1351  */
1352 static void rdma_seq_err(struct qib_qp *qp, struct qib_ibport *ibp, u32 psn,
1353                          struct qib_ctxtdata *rcd)
1354 {
1355         struct qib_swqe *wqe;
1356
1357         /* Remove QP from retry timer */
1358         if (qp->s_flags & (QIB_S_TIMER | QIB_S_WAIT_RNR)) {
1359                 qp->s_flags &= ~(QIB_S_TIMER | QIB_S_WAIT_RNR);
1360                 del_timer(&qp->s_timer);
1361         }
1362
1363         wqe = get_swqe_ptr(qp, qp->s_acked);
1364
1365         while (qib_cmp24(psn, wqe->lpsn) > 0) {
1366                 if (wqe->wr.opcode == IB_WR_RDMA_READ ||
1367                     wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1368                     wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)
1369                         break;
1370                 wqe = do_rc_completion(qp, wqe, ibp);
1371         }
1372
1373         ibp->n_rdma_seq++;
1374         qp->r_flags |= QIB_R_RDMAR_SEQ;
1375         qib_restart_rc(qp, qp->s_last_psn + 1, 0);
1376         if (list_empty(&qp->rspwait)) {
1377                 qp->r_flags |= QIB_R_RSP_SEND;
1378                 atomic_inc(&qp->refcount);
1379                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
1380         }
1381 }
1382
1383 /**
1384  * qib_rc_rcv_resp - process an incoming RC response packet
1385  * @ibp: the port this packet came in on
1386  * @ohdr: the other headers for this packet
1387  * @data: the packet data
1388  * @tlen: the packet length
1389  * @qp: the QP for this packet
1390  * @opcode: the opcode for this packet
1391  * @psn: the packet sequence number for this packet
1392  * @hdrsize: the header length
1393  * @pmtu: the path MTU
1394  *
1395  * This is called from qib_rc_rcv() to process an incoming RC response
1396  * packet for the given QP.
1397  * Called at interrupt level.
1398  */
1399 static void qib_rc_rcv_resp(struct qib_ibport *ibp,
1400                             struct qib_other_headers *ohdr,
1401                             void *data, u32 tlen,
1402                             struct qib_qp *qp,
1403                             u32 opcode,
1404                             u32 psn, u32 hdrsize, u32 pmtu,
1405                             struct qib_ctxtdata *rcd)
1406 {
1407         struct qib_swqe *wqe;
1408         struct qib_pportdata *ppd = ppd_from_ibp(ibp);
1409         enum ib_wc_status status;
1410         unsigned long flags;
1411         int diff;
1412         u32 pad;
1413         u32 aeth;
1414         u64 val;
1415
1416         if (opcode != OP(RDMA_READ_RESPONSE_MIDDLE)) {
1417                 /*
1418                  * If ACK'd PSN on SDMA busy list try to make progress to
1419                  * reclaim SDMA credits.
1420                  */
1421                 if ((qib_cmp24(psn, qp->s_sending_psn) >= 0) &&
1422                     (qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) <= 0)) {
1423
1424                         /*
1425                          * If send tasklet not running attempt to progress
1426                          * SDMA queue.
1427                          */
1428                         if (!(qp->s_flags & QIB_S_BUSY)) {
1429                                 /* Acquire SDMA Lock */
1430                                 spin_lock_irqsave(&ppd->sdma_lock, flags);
1431                                 /* Invoke sdma make progress */
1432                                 qib_sdma_make_progress(ppd);
1433                                 /* Release SDMA Lock */
1434                                 spin_unlock_irqrestore(&ppd->sdma_lock, flags);
1435                         }
1436                 }
1437         }
1438
1439         spin_lock_irqsave(&qp->s_lock, flags);
1440         if (!(ib_qib_state_ops[qp->state] & QIB_PROCESS_RECV_OK))
1441                 goto ack_done;
1442
1443         /* Ignore invalid responses. */
1444         if (qib_cmp24(psn, qp->s_next_psn) >= 0)
1445                 goto ack_done;
1446
1447         /* Ignore duplicate responses. */
1448         diff = qib_cmp24(psn, qp->s_last_psn);
1449         if (unlikely(diff <= 0)) {
1450                 /* Update credits for "ghost" ACKs */
1451                 if (diff == 0 && opcode == OP(ACKNOWLEDGE)) {
1452                         aeth = be32_to_cpu(ohdr->u.aeth);
1453                         if ((aeth >> 29) == 0)
1454                                 qib_get_credit(qp, aeth);
1455                 }
1456                 goto ack_done;
1457         }
1458
1459         /*
1460          * Skip everything other than the PSN we expect, if we are waiting
1461          * for a reply to a restarted RDMA read or atomic op.
1462          */
1463         if (qp->r_flags & QIB_R_RDMAR_SEQ) {
1464                 if (qib_cmp24(psn, qp->s_last_psn + 1) != 0)
1465                         goto ack_done;
1466                 qp->r_flags &= ~QIB_R_RDMAR_SEQ;
1467         }
1468
1469         if (unlikely(qp->s_acked == qp->s_tail))
1470                 goto ack_done;
1471         wqe = get_swqe_ptr(qp, qp->s_acked);
1472         status = IB_WC_SUCCESS;
1473
1474         switch (opcode) {
1475         case OP(ACKNOWLEDGE):
1476         case OP(ATOMIC_ACKNOWLEDGE):
1477         case OP(RDMA_READ_RESPONSE_FIRST):
1478                 aeth = be32_to_cpu(ohdr->u.aeth);
1479                 if (opcode == OP(ATOMIC_ACKNOWLEDGE)) {
1480                         __be32 *p = ohdr->u.at.atomic_ack_eth;
1481
1482                         val = ((u64) be32_to_cpu(p[0]) << 32) |
1483                                 be32_to_cpu(p[1]);
1484                 } else
1485                         val = 0;
1486                 if (!do_rc_ack(qp, aeth, psn, opcode, val, rcd) ||
1487                     opcode != OP(RDMA_READ_RESPONSE_FIRST))
1488                         goto ack_done;
1489                 hdrsize += 4;
1490                 wqe = get_swqe_ptr(qp, qp->s_acked);
1491                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1492                         goto ack_op_err;
1493                 /*
1494                  * If this is a response to a resent RDMA read, we
1495                  * have to be careful to copy the data to the right
1496                  * location.
1497                  */
1498                 qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
1499                                                   wqe, psn, pmtu);
1500                 goto read_middle;
1501
1502         case OP(RDMA_READ_RESPONSE_MIDDLE):
1503                 /* no AETH, no ACK */
1504                 if (unlikely(qib_cmp24(psn, qp->s_last_psn + 1)))
1505                         goto ack_seq_err;
1506                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1507                         goto ack_op_err;
1508 read_middle:
1509                 if (unlikely(tlen != (hdrsize + pmtu + 4)))
1510                         goto ack_len_err;
1511                 if (unlikely(pmtu >= qp->s_rdma_read_len))
1512                         goto ack_len_err;
1513
1514                 /*
1515                  * We got a response so update the timeout.
1516                  * 4.096 usec. * (1 << qp->timeout)
1517                  */
1518                 qp->s_flags |= QIB_S_TIMER;
1519                 mod_timer(&qp->s_timer, jiffies + qp->timeout_jiffies);
1520                 if (qp->s_flags & QIB_S_WAIT_ACK) {
1521                         qp->s_flags &= ~QIB_S_WAIT_ACK;
1522                         qib_schedule_send(qp);
1523                 }
1524
1525                 if (opcode == OP(RDMA_READ_RESPONSE_MIDDLE))
1526                         qp->s_retry = qp->s_retry_cnt;
1527
1528                 /*
1529                  * Update the RDMA receive state but do the copy w/o
1530                  * holding the locks and blocking interrupts.
1531                  */
1532                 qp->s_rdma_read_len -= pmtu;
1533                 update_last_psn(qp, psn);
1534                 spin_unlock_irqrestore(&qp->s_lock, flags);
1535                 qib_copy_sge(&qp->s_rdma_read_sge, data, pmtu, 0);
1536                 goto bail;
1537
1538         case OP(RDMA_READ_RESPONSE_ONLY):
1539                 aeth = be32_to_cpu(ohdr->u.aeth);
1540                 if (!do_rc_ack(qp, aeth, psn, opcode, 0, rcd))
1541                         goto ack_done;
1542                 /* Get the number of bytes the message was padded by. */
1543                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1544                 /*
1545                  * Check that the data size is >= 0 && <= pmtu.
1546                  * Remember to account for the AETH header (4) and
1547                  * ICRC (4).
1548                  */
1549                 if (unlikely(tlen < (hdrsize + pad + 8)))
1550                         goto ack_len_err;
1551                 /*
1552                  * If this is a response to a resent RDMA read, we
1553                  * have to be careful to copy the data to the right
1554                  * location.
1555                  */
1556                 wqe = get_swqe_ptr(qp, qp->s_acked);
1557                 qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
1558                                                   wqe, psn, pmtu);
1559                 goto read_last;
1560
1561         case OP(RDMA_READ_RESPONSE_LAST):
1562                 /* ACKs READ req. */
1563                 if (unlikely(qib_cmp24(psn, qp->s_last_psn + 1)))
1564                         goto ack_seq_err;
1565                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1566                         goto ack_op_err;
1567                 /* Get the number of bytes the message was padded by. */
1568                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1569                 /*
1570                  * Check that the data size is >= 1 && <= pmtu.
1571                  * Remember to account for the AETH header (4) and
1572                  * ICRC (4).
1573                  */
1574                 if (unlikely(tlen <= (hdrsize + pad + 8)))
1575                         goto ack_len_err;
1576 read_last:
1577                 tlen -= hdrsize + pad + 8;
1578                 if (unlikely(tlen != qp->s_rdma_read_len))
1579                         goto ack_len_err;
1580                 aeth = be32_to_cpu(ohdr->u.aeth);
1581                 qib_copy_sge(&qp->s_rdma_read_sge, data, tlen, 0);
1582                 WARN_ON(qp->s_rdma_read_sge.num_sge);
1583                 (void) do_rc_ack(qp, aeth, psn,
1584                                  OP(RDMA_READ_RESPONSE_LAST), 0, rcd);
1585                 goto ack_done;
1586         }
1587
1588 ack_op_err:
1589         status = IB_WC_LOC_QP_OP_ERR;
1590         goto ack_err;
1591
1592 ack_seq_err:
1593         rdma_seq_err(qp, ibp, psn, rcd);
1594         goto ack_done;
1595
1596 ack_len_err:
1597         status = IB_WC_LOC_LEN_ERR;
1598 ack_err:
1599         if (qp->s_last == qp->s_acked) {
1600                 qib_send_complete(qp, wqe, status);
1601                 qib_error_qp(qp, IB_WC_WR_FLUSH_ERR);
1602         }
1603 ack_done:
1604         spin_unlock_irqrestore(&qp->s_lock, flags);
1605 bail:
1606         return;
1607 }
1608
1609 /**
1610  * qib_rc_rcv_error - process an incoming duplicate or error RC packet
1611  * @ohdr: the other headers for this packet
1612  * @data: the packet data
1613  * @qp: the QP for this packet
1614  * @opcode: the opcode for this packet
1615  * @psn: the packet sequence number for this packet
1616  * @diff: the difference between the PSN and the expected PSN
1617  *
1618  * This is called from qib_rc_rcv() to process an unexpected
1619  * incoming RC packet for the given QP.
1620  * Called at interrupt level.
1621  * Return 1 if no more processing is needed; otherwise return 0 to
1622  * schedule a response to be sent.
1623  */
1624 static int qib_rc_rcv_error(struct qib_other_headers *ohdr,
1625                             void *data,
1626                             struct qib_qp *qp,
1627                             u32 opcode,
1628                             u32 psn,
1629                             int diff,
1630                             struct qib_ctxtdata *rcd)
1631 {
1632         struct qib_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
1633         struct qib_ack_entry *e;
1634         unsigned long flags;
1635         u8 i, prev;
1636         int old_req;
1637
1638         if (diff > 0) {
1639                 /*
1640                  * Packet sequence error.
1641                  * A NAK will ACK earlier sends and RDMA writes.
1642                  * Don't queue the NAK if we already sent one.
1643                  */
1644                 if (!qp->r_nak_state) {
1645                         ibp->n_rc_seqnak++;
1646                         qp->r_nak_state = IB_NAK_PSN_ERROR;
1647                         /* Use the expected PSN. */
1648                         qp->r_ack_psn = qp->r_psn;
1649                         /*
1650                          * Wait to send the sequence NAK until all packets
1651                          * in the receive queue have been processed.
1652                          * Otherwise, we end up propagating congestion.
1653                          */
1654                         if (list_empty(&qp->rspwait)) {
1655                                 qp->r_flags |= QIB_R_RSP_NAK;
1656                                 atomic_inc(&qp->refcount);
1657                                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
1658                         }
1659                 }
1660                 goto done;
1661         }
1662
1663         /*
1664          * Handle a duplicate request.  Don't re-execute SEND, RDMA
1665          * write or atomic op.  Don't NAK errors, just silently drop
1666          * the duplicate request.  Note that r_sge, r_len, and
1667          * r_rcv_len may be in use so don't modify them.
1668          *
1669          * We are supposed to ACK the earliest duplicate PSN but we
1670          * can coalesce an outstanding duplicate ACK.  We have to
1671          * send the earliest so that RDMA reads can be restarted at
1672          * the requester's expected PSN.
1673          *
1674          * First, find where this duplicate PSN falls within the
1675          * ACKs previously sent.
1676          * old_req is true if there is an older response that is scheduled
1677          * to be sent before sending this one.
1678          */
1679         e = NULL;
1680         old_req = 1;
1681         ibp->n_rc_dupreq++;
1682
1683         spin_lock_irqsave(&qp->s_lock, flags);
1684
1685         for (i = qp->r_head_ack_queue; ; i = prev) {
1686                 if (i == qp->s_tail_ack_queue)
1687                         old_req = 0;
1688                 if (i)
1689                         prev = i - 1;
1690                 else
1691                         prev = QIB_MAX_RDMA_ATOMIC;
1692                 if (prev == qp->r_head_ack_queue) {
1693                         e = NULL;
1694                         break;
1695                 }
1696                 e = &qp->s_ack_queue[prev];
1697                 if (!e->opcode) {
1698                         e = NULL;
1699                         break;
1700                 }
1701                 if (qib_cmp24(psn, e->psn) >= 0) {
1702                         if (prev == qp->s_tail_ack_queue &&
1703                             qib_cmp24(psn, e->lpsn) <= 0)
1704                                 old_req = 0;
1705                         break;
1706                 }
1707         }
1708         switch (opcode) {
1709         case OP(RDMA_READ_REQUEST): {
1710                 struct ib_reth *reth;
1711                 u32 offset;
1712                 u32 len;
1713
1714                 /*
1715                  * If we didn't find the RDMA read request in the ack queue,
1716                  * we can ignore this request.
1717                  */
1718                 if (!e || e->opcode != OP(RDMA_READ_REQUEST))
1719                         goto unlock_done;
1720                 /* RETH comes after BTH */
1721                 reth = &ohdr->u.rc.reth;
1722                 /*
1723                  * Address range must be a subset of the original
1724                  * request and start on pmtu boundaries.
1725                  * We reuse the old ack_queue slot since the requester
1726                  * should not back up and request an earlier PSN for the
1727                  * same request.
1728                  */
1729                 offset = ((psn - e->psn) & QIB_PSN_MASK) *
1730                         qp->pmtu;
1731                 len = be32_to_cpu(reth->length);
1732                 if (unlikely(offset + len != e->rdma_sge.sge_length))
1733                         goto unlock_done;
1734                 if (e->rdma_sge.mr) {
1735                         qib_put_mr(e->rdma_sge.mr);
1736                         e->rdma_sge.mr = NULL;
1737                 }
1738                 if (len != 0) {
1739                         u32 rkey = be32_to_cpu(reth->rkey);
1740                         u64 vaddr = be64_to_cpu(reth->vaddr);
1741                         int ok;
1742
1743                         ok = qib_rkey_ok(qp, &e->rdma_sge, len, vaddr, rkey,
1744                                          IB_ACCESS_REMOTE_READ);
1745                         if (unlikely(!ok))
1746                                 goto unlock_done;
1747                 } else {
1748                         e->rdma_sge.vaddr = NULL;
1749                         e->rdma_sge.length = 0;
1750                         e->rdma_sge.sge_length = 0;
1751                 }
1752                 e->psn = psn;
1753                 if (old_req)
1754                         goto unlock_done;
1755                 qp->s_tail_ack_queue = prev;
1756                 break;
1757         }
1758
1759         case OP(COMPARE_SWAP):
1760         case OP(FETCH_ADD): {
1761                 /*
1762                  * If we didn't find the atomic request in the ack queue
1763                  * or the send tasklet is already backed up to send an
1764                  * earlier entry, we can ignore this request.
1765                  */
1766                 if (!e || e->opcode != (u8) opcode || old_req)
1767                         goto unlock_done;
1768                 qp->s_tail_ack_queue = prev;
1769                 break;
1770         }
1771
1772         default:
1773                 /*
1774                  * Ignore this operation if it doesn't request an ACK
1775                  * or an earlier RDMA read or atomic is going to be resent.
1776                  */
1777                 if (!(psn & IB_BTH_REQ_ACK) || old_req)
1778                         goto unlock_done;
1779                 /*
1780                  * Resend the most recent ACK if this request is
1781                  * after all the previous RDMA reads and atomics.
1782                  */
1783                 if (i == qp->r_head_ack_queue) {
1784                         spin_unlock_irqrestore(&qp->s_lock, flags);
1785                         qp->r_nak_state = 0;
1786                         qp->r_ack_psn = qp->r_psn - 1;
1787                         goto send_ack;
1788                 }
1789                 /*
1790                  * Try to send a simple ACK to work around a Mellanox bug
1791                  * which doesn't accept a RDMA read response or atomic
1792                  * response as an ACK for earlier SENDs or RDMA writes.
1793                  */
1794                 if (!(qp->s_flags & QIB_S_RESP_PENDING)) {
1795                         spin_unlock_irqrestore(&qp->s_lock, flags);
1796                         qp->r_nak_state = 0;
1797                         qp->r_ack_psn = qp->s_ack_queue[i].psn - 1;
1798                         goto send_ack;
1799                 }
1800                 /*
1801                  * Resend the RDMA read or atomic op which
1802                  * ACKs this duplicate request.
1803                  */
1804                 qp->s_tail_ack_queue = i;
1805                 break;
1806         }
1807         qp->s_ack_state = OP(ACKNOWLEDGE);
1808         qp->s_flags |= QIB_S_RESP_PENDING;
1809         qp->r_nak_state = 0;
1810         qib_schedule_send(qp);
1811
1812 unlock_done:
1813         spin_unlock_irqrestore(&qp->s_lock, flags);
1814 done:
1815         return 1;
1816
1817 send_ack:
1818         return 0;
1819 }
1820
1821 void qib_rc_error(struct qib_qp *qp, enum ib_wc_status err)
1822 {
1823         unsigned long flags;
1824         int lastwqe;
1825
1826         spin_lock_irqsave(&qp->s_lock, flags);
1827         lastwqe = qib_error_qp(qp, err);
1828         spin_unlock_irqrestore(&qp->s_lock, flags);
1829
1830         if (lastwqe) {
1831                 struct ib_event ev;
1832
1833                 ev.device = qp->ibqp.device;
1834                 ev.element.qp = &qp->ibqp;
1835                 ev.event = IB_EVENT_QP_LAST_WQE_REACHED;
1836                 qp->ibqp.event_handler(&ev, qp->ibqp.qp_context);
1837         }
1838 }
1839
1840 static inline void qib_update_ack_queue(struct qib_qp *qp, unsigned n)
1841 {
1842         unsigned next;
1843
1844         next = n + 1;
1845         if (next > QIB_MAX_RDMA_ATOMIC)
1846                 next = 0;
1847         qp->s_tail_ack_queue = next;
1848         qp->s_ack_state = OP(ACKNOWLEDGE);
1849 }
1850
1851 /**
1852  * qib_rc_rcv - process an incoming RC packet
1853  * @rcd: the context pointer
1854  * @hdr: the header of this packet
1855  * @has_grh: true if the header has a GRH
1856  * @data: the packet data
1857  * @tlen: the packet length
1858  * @qp: the QP for this packet
1859  *
1860  * This is called from qib_qp_rcv() to process an incoming RC packet
1861  * for the given QP.
1862  * Called at interrupt level.
1863  */
1864 void qib_rc_rcv(struct qib_ctxtdata *rcd, struct qib_ib_header *hdr,
1865                 int has_grh, void *data, u32 tlen, struct qib_qp *qp)
1866 {
1867         struct qib_ibport *ibp = &rcd->ppd->ibport_data;
1868         struct qib_other_headers *ohdr;
1869         u32 opcode;
1870         u32 hdrsize;
1871         u32 psn;
1872         u32 pad;
1873         struct ib_wc wc;
1874         u32 pmtu = qp->pmtu;
1875         int diff;
1876         struct ib_reth *reth;
1877         unsigned long flags;
1878         int ret;
1879
1880         /* Check for GRH */
1881         if (!has_grh) {
1882                 ohdr = &hdr->u.oth;
1883                 hdrsize = 8 + 12;       /* LRH + BTH */
1884         } else {
1885                 ohdr = &hdr->u.l.oth;
1886                 hdrsize = 8 + 40 + 12;  /* LRH + GRH + BTH */
1887         }
1888
1889         opcode = be32_to_cpu(ohdr->bth[0]);
1890         if (qib_ruc_check_hdr(ibp, hdr, has_grh, qp, opcode))
1891                 return;
1892
1893         psn = be32_to_cpu(ohdr->bth[2]);
1894         opcode >>= 24;
1895
1896         /*
1897          * Process responses (ACKs) before anything else.  Note that the
1898          * packet sequence number will be for something in the send work
1899          * queue rather than the expected receive packet sequence number.
1900          * In other words, this QP is the requester.
1901          */
1902         if (opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
1903             opcode <= OP(ATOMIC_ACKNOWLEDGE)) {
1904                 qib_rc_rcv_resp(ibp, ohdr, data, tlen, qp, opcode, psn,
1905                                 hdrsize, pmtu, rcd);
1906                 return;
1907         }
1908
1909         /* Compute 24 bits worth of difference. */
1910         diff = qib_cmp24(psn, qp->r_psn);
1911         if (unlikely(diff)) {
1912                 if (qib_rc_rcv_error(ohdr, data, qp, opcode, psn, diff, rcd))
1913                         return;
1914                 goto send_ack;
1915         }
1916
1917         /* Check for opcode sequence errors. */
1918         switch (qp->r_state) {
1919         case OP(SEND_FIRST):
1920         case OP(SEND_MIDDLE):
1921                 if (opcode == OP(SEND_MIDDLE) ||
1922                     opcode == OP(SEND_LAST) ||
1923                     opcode == OP(SEND_LAST_WITH_IMMEDIATE))
1924                         break;
1925                 goto nack_inv;
1926
1927         case OP(RDMA_WRITE_FIRST):
1928         case OP(RDMA_WRITE_MIDDLE):
1929                 if (opcode == OP(RDMA_WRITE_MIDDLE) ||
1930                     opcode == OP(RDMA_WRITE_LAST) ||
1931                     opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
1932                         break;
1933                 goto nack_inv;
1934
1935         default:
1936                 if (opcode == OP(SEND_MIDDLE) ||
1937                     opcode == OP(SEND_LAST) ||
1938                     opcode == OP(SEND_LAST_WITH_IMMEDIATE) ||
1939                     opcode == OP(RDMA_WRITE_MIDDLE) ||
1940                     opcode == OP(RDMA_WRITE_LAST) ||
1941                     opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
1942                         goto nack_inv;
1943                 /*
1944                  * Note that it is up to the requester to not send a new
1945                  * RDMA read or atomic operation before receiving an ACK
1946                  * for the previous operation.
1947                  */
1948                 break;
1949         }
1950
1951         if (qp->state == IB_QPS_RTR && !(qp->r_flags & QIB_R_COMM_EST)) {
1952                 qp->r_flags |= QIB_R_COMM_EST;
1953                 if (qp->ibqp.event_handler) {
1954                         struct ib_event ev;
1955
1956                         ev.device = qp->ibqp.device;
1957                         ev.element.qp = &qp->ibqp;
1958                         ev.event = IB_EVENT_COMM_EST;
1959                         qp->ibqp.event_handler(&ev, qp->ibqp.qp_context);
1960                 }
1961         }
1962
1963         /* OK, process the packet. */
1964         switch (opcode) {
1965         case OP(SEND_FIRST):
1966                 ret = qib_get_rwqe(qp, 0);
1967                 if (ret < 0)
1968                         goto nack_op_err;
1969                 if (!ret)
1970                         goto rnr_nak;
1971                 qp->r_rcv_len = 0;
1972                 /* FALLTHROUGH */
1973         case OP(SEND_MIDDLE):
1974         case OP(RDMA_WRITE_MIDDLE):
1975 send_middle:
1976                 /* Check for invalid length PMTU or posted rwqe len. */
1977                 if (unlikely(tlen != (hdrsize + pmtu + 4)))
1978                         goto nack_inv;
1979                 qp->r_rcv_len += pmtu;
1980                 if (unlikely(qp->r_rcv_len > qp->r_len))
1981                         goto nack_inv;
1982                 qib_copy_sge(&qp->r_sge, data, pmtu, 1);
1983                 break;
1984
1985         case OP(RDMA_WRITE_LAST_WITH_IMMEDIATE):
1986                 /* consume RWQE */
1987                 ret = qib_get_rwqe(qp, 1);
1988                 if (ret < 0)
1989                         goto nack_op_err;
1990                 if (!ret)
1991                         goto rnr_nak;
1992                 goto send_last_imm;
1993
1994         case OP(SEND_ONLY):
1995         case OP(SEND_ONLY_WITH_IMMEDIATE):
1996                 ret = qib_get_rwqe(qp, 0);
1997                 if (ret < 0)
1998                         goto nack_op_err;
1999                 if (!ret)
2000                         goto rnr_nak;
2001                 qp->r_rcv_len = 0;
2002                 if (opcode == OP(SEND_ONLY))
2003                         goto no_immediate_data;
2004                 /* FALLTHROUGH for SEND_ONLY_WITH_IMMEDIATE */
2005         case OP(SEND_LAST_WITH_IMMEDIATE):
2006 send_last_imm:
2007                 wc.ex.imm_data = ohdr->u.imm_data;
2008                 hdrsize += 4;
2009                 wc.wc_flags = IB_WC_WITH_IMM;
2010                 goto send_last;
2011         case OP(SEND_LAST):
2012         case OP(RDMA_WRITE_LAST):
2013 no_immediate_data:
2014                 wc.wc_flags = 0;
2015                 wc.ex.imm_data = 0;
2016 send_last:
2017                 /* Get the number of bytes the message was padded by. */
2018                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
2019                 /* Check for invalid length. */
2020                 /* XXX LAST len should be >= 1 */
2021                 if (unlikely(tlen < (hdrsize + pad + 4)))
2022                         goto nack_inv;
2023                 /* Don't count the CRC. */
2024                 tlen -= (hdrsize + pad + 4);
2025                 wc.byte_len = tlen + qp->r_rcv_len;
2026                 if (unlikely(wc.byte_len > qp->r_len))
2027                         goto nack_inv;
2028                 qib_copy_sge(&qp->r_sge, data, tlen, 1);
2029                 qib_put_ss(&qp->r_sge);
2030                 qp->r_msn++;
2031                 if (!test_and_clear_bit(QIB_R_WRID_VALID, &qp->r_aflags))
2032                         break;
2033                 wc.wr_id = qp->r_wr_id;
2034                 wc.status = IB_WC_SUCCESS;
2035                 if (opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE) ||
2036                     opcode == OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE))
2037                         wc.opcode = IB_WC_RECV_RDMA_WITH_IMM;
2038                 else
2039                         wc.opcode = IB_WC_RECV;
2040                 wc.qp = &qp->ibqp;
2041                 wc.src_qp = qp->remote_qpn;
2042                 wc.slid = qp->remote_ah_attr.dlid;
2043                 wc.sl = qp->remote_ah_attr.sl;
2044                 /* zero fields that are N/A */
2045                 wc.vendor_err = 0;
2046                 wc.pkey_index = 0;
2047                 wc.dlid_path_bits = 0;
2048                 wc.port_num = 0;
2049                 /* Signal completion event if the solicited bit is set. */
2050                 qib_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
2051                              (ohdr->bth[0] &
2052                               cpu_to_be32(IB_BTH_SOLICITED)) != 0);
2053                 break;
2054
2055         case OP(RDMA_WRITE_FIRST):
2056         case OP(RDMA_WRITE_ONLY):
2057         case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE):
2058                 if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_WRITE)))
2059                         goto nack_inv;
2060                 /* consume RWQE */
2061                 reth = &ohdr->u.rc.reth;
2062                 hdrsize += sizeof(*reth);
2063                 qp->r_len = be32_to_cpu(reth->length);
2064                 qp->r_rcv_len = 0;
2065                 qp->r_sge.sg_list = NULL;
2066                 if (qp->r_len != 0) {
2067                         u32 rkey = be32_to_cpu(reth->rkey);
2068                         u64 vaddr = be64_to_cpu(reth->vaddr);
2069                         int ok;
2070
2071                         /* Check rkey & NAK */
2072                         ok = qib_rkey_ok(qp, &qp->r_sge.sge, qp->r_len, vaddr,
2073                                          rkey, IB_ACCESS_REMOTE_WRITE);
2074                         if (unlikely(!ok))
2075                                 goto nack_acc;
2076                         qp->r_sge.num_sge = 1;
2077                 } else {
2078                         qp->r_sge.num_sge = 0;
2079                         qp->r_sge.sge.mr = NULL;
2080                         qp->r_sge.sge.vaddr = NULL;
2081                         qp->r_sge.sge.length = 0;
2082                         qp->r_sge.sge.sge_length = 0;
2083                 }
2084                 if (opcode == OP(RDMA_WRITE_FIRST))
2085                         goto send_middle;
2086                 else if (opcode == OP(RDMA_WRITE_ONLY))
2087                         goto no_immediate_data;
2088                 ret = qib_get_rwqe(qp, 1);
2089                 if (ret < 0)
2090                         goto nack_op_err;
2091                 if (!ret)
2092                         goto rnr_nak;
2093                 wc.ex.imm_data = ohdr->u.rc.imm_data;
2094                 hdrsize += 4;
2095                 wc.wc_flags = IB_WC_WITH_IMM;
2096                 goto send_last;
2097
2098         case OP(RDMA_READ_REQUEST): {
2099                 struct qib_ack_entry *e;
2100                 u32 len;
2101                 u8 next;
2102
2103                 if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_READ)))
2104                         goto nack_inv;
2105                 next = qp->r_head_ack_queue + 1;
2106                 /* s_ack_queue is size QIB_MAX_RDMA_ATOMIC+1 so use > not >= */
2107                 if (next > QIB_MAX_RDMA_ATOMIC)
2108                         next = 0;
2109                 spin_lock_irqsave(&qp->s_lock, flags);
2110                 if (unlikely(next == qp->s_tail_ack_queue)) {
2111                         if (!qp->s_ack_queue[next].sent)
2112                                 goto nack_inv_unlck;
2113                         qib_update_ack_queue(qp, next);
2114                 }
2115                 e = &qp->s_ack_queue[qp->r_head_ack_queue];
2116                 if (e->opcode == OP(RDMA_READ_REQUEST) && e->rdma_sge.mr) {
2117                         qib_put_mr(e->rdma_sge.mr);
2118                         e->rdma_sge.mr = NULL;
2119                 }
2120                 reth = &ohdr->u.rc.reth;
2121                 len = be32_to_cpu(reth->length);
2122                 if (len) {
2123                         u32 rkey = be32_to_cpu(reth->rkey);
2124                         u64 vaddr = be64_to_cpu(reth->vaddr);
2125                         int ok;
2126
2127                         /* Check rkey & NAK */
2128                         ok = qib_rkey_ok(qp, &e->rdma_sge, len, vaddr,
2129                                          rkey, IB_ACCESS_REMOTE_READ);
2130                         if (unlikely(!ok))
2131                                 goto nack_acc_unlck;
2132                         /*
2133                          * Update the next expected PSN.  We add 1 later
2134                          * below, so only add the remainder here.
2135                          */
2136                         if (len > pmtu)
2137                                 qp->r_psn += (len - 1) / pmtu;
2138                 } else {
2139                         e->rdma_sge.mr = NULL;
2140                         e->rdma_sge.vaddr = NULL;
2141                         e->rdma_sge.length = 0;
2142                         e->rdma_sge.sge_length = 0;
2143                 }
2144                 e->opcode = opcode;
2145                 e->sent = 0;
2146                 e->psn = psn;
2147                 e->lpsn = qp->r_psn;
2148                 /*
2149                  * We need to increment the MSN here instead of when we
2150                  * finish sending the result since a duplicate request would
2151                  * increment it more than once.
2152                  */
2153                 qp->r_msn++;
2154                 qp->r_psn++;
2155                 qp->r_state = opcode;
2156                 qp->r_nak_state = 0;
2157                 qp->r_head_ack_queue = next;
2158
2159                 /* Schedule the send tasklet. */
2160                 qp->s_flags |= QIB_S_RESP_PENDING;
2161                 qib_schedule_send(qp);
2162
2163                 goto sunlock;
2164         }
2165
2166         case OP(COMPARE_SWAP):
2167         case OP(FETCH_ADD): {
2168                 struct ib_atomic_eth *ateth;
2169                 struct qib_ack_entry *e;
2170                 u64 vaddr;
2171                 atomic64_t *maddr;
2172                 u64 sdata;
2173                 u32 rkey;
2174                 u8 next;
2175
2176                 if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_ATOMIC)))
2177                         goto nack_inv;
2178                 next = qp->r_head_ack_queue + 1;
2179                 if (next > QIB_MAX_RDMA_ATOMIC)
2180                         next = 0;
2181                 spin_lock_irqsave(&qp->s_lock, flags);
2182                 if (unlikely(next == qp->s_tail_ack_queue)) {
2183                         if (!qp->s_ack_queue[next].sent)
2184                                 goto nack_inv_unlck;
2185                         qib_update_ack_queue(qp, next);
2186                 }
2187                 e = &qp->s_ack_queue[qp->r_head_ack_queue];
2188                 if (e->opcode == OP(RDMA_READ_REQUEST) && e->rdma_sge.mr) {
2189                         qib_put_mr(e->rdma_sge.mr);
2190                         e->rdma_sge.mr = NULL;
2191                 }
2192                 ateth = &ohdr->u.atomic_eth;
2193                 vaddr = ((u64) be32_to_cpu(ateth->vaddr[0]) << 32) |
2194                         be32_to_cpu(ateth->vaddr[1]);
2195                 if (unlikely(vaddr & (sizeof(u64) - 1)))
2196                         goto nack_inv_unlck;
2197                 rkey = be32_to_cpu(ateth->rkey);
2198                 /* Check rkey & NAK */
2199                 if (unlikely(!qib_rkey_ok(qp, &qp->r_sge.sge, sizeof(u64),
2200                                           vaddr, rkey,
2201                                           IB_ACCESS_REMOTE_ATOMIC)))
2202                         goto nack_acc_unlck;
2203                 /* Perform atomic OP and save result. */
2204                 maddr = (atomic64_t *) qp->r_sge.sge.vaddr;
2205                 sdata = be64_to_cpu(ateth->swap_data);
2206                 e->atomic_data = (opcode == OP(FETCH_ADD)) ?
2207                         (u64) atomic64_add_return(sdata, maddr) - sdata :
2208                         (u64) cmpxchg((u64 *) qp->r_sge.sge.vaddr,
2209                                       be64_to_cpu(ateth->compare_data),
2210                                       sdata);
2211                 qib_put_mr(qp->r_sge.sge.mr);
2212                 qp->r_sge.num_sge = 0;
2213                 e->opcode = opcode;
2214                 e->sent = 0;
2215                 e->psn = psn;
2216                 e->lpsn = psn;
2217                 qp->r_msn++;
2218                 qp->r_psn++;
2219                 qp->r_state = opcode;
2220                 qp->r_nak_state = 0;
2221                 qp->r_head_ack_queue = next;
2222
2223                 /* Schedule the send tasklet. */
2224                 qp->s_flags |= QIB_S_RESP_PENDING;
2225                 qib_schedule_send(qp);
2226
2227                 goto sunlock;
2228         }
2229
2230         default:
2231                 /* NAK unknown opcodes. */
2232                 goto nack_inv;
2233         }
2234         qp->r_psn++;
2235         qp->r_state = opcode;
2236         qp->r_ack_psn = psn;
2237         qp->r_nak_state = 0;
2238         /* Send an ACK if requested or required. */
2239         if (psn & (1 << 31))
2240                 goto send_ack;
2241         return;
2242
2243 rnr_nak:
2244         qp->r_nak_state = IB_RNR_NAK | qp->r_min_rnr_timer;
2245         qp->r_ack_psn = qp->r_psn;
2246         /* Queue RNR NAK for later */
2247         if (list_empty(&qp->rspwait)) {
2248                 qp->r_flags |= QIB_R_RSP_NAK;
2249                 atomic_inc(&qp->refcount);
2250                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
2251         }
2252         return;
2253
2254 nack_op_err:
2255         qib_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
2256         qp->r_nak_state = IB_NAK_REMOTE_OPERATIONAL_ERROR;
2257         qp->r_ack_psn = qp->r_psn;
2258         /* Queue NAK for later */
2259         if (list_empty(&qp->rspwait)) {
2260                 qp->r_flags |= QIB_R_RSP_NAK;
2261                 atomic_inc(&qp->refcount);
2262                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
2263         }
2264         return;
2265
2266 nack_inv_unlck:
2267         spin_unlock_irqrestore(&qp->s_lock, flags);
2268 nack_inv:
2269         qib_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
2270         qp->r_nak_state = IB_NAK_INVALID_REQUEST;
2271         qp->r_ack_psn = qp->r_psn;
2272         /* Queue NAK for later */
2273         if (list_empty(&qp->rspwait)) {
2274                 qp->r_flags |= QIB_R_RSP_NAK;
2275                 atomic_inc(&qp->refcount);
2276                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
2277         }
2278         return;
2279
2280 nack_acc_unlck:
2281         spin_unlock_irqrestore(&qp->s_lock, flags);
2282 nack_acc:
2283         qib_rc_error(qp, IB_WC_LOC_PROT_ERR);
2284         qp->r_nak_state = IB_NAK_REMOTE_ACCESS_ERROR;
2285         qp->r_ack_psn = qp->r_psn;
2286 send_ack:
2287         qib_send_rc_ack(qp);
2288         return;
2289
2290 sunlock:
2291         spin_unlock_irqrestore(&qp->s_lock, flags);
2292 }