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
  42 static u32 restart_sge(struct rvt_sge_state *ss, struct rvt_swqe *wqe,
  43                        u32 psn, u32 pmtu)
  44 {
  45         u32 len;
  46
  47         len = ((psn - wqe->psn) & QIB_PSN_MASK) * pmtu;
  48         ss->sge = wqe->sg_list[0];
  49         ss->sg_list = wqe->sg_list + 1;
  50         ss->num_sge = wqe->wr.num_sge;
  51         ss->total_len = wqe->length;
  52         rvt_skip_sge(ss, len, false);
  53         return wqe->length - len;
  54 }
  55
  56 /**
  57  * qib_make_rc_ack - construct a response packet (ACK, NAK, or RDMA read)
  58  * @dev: the device for this QP
  59  * @qp: a pointer to the QP
  60  * @ohdr: a pointer to the IB header being constructed
  61  * @pmtu: the path MTU
  62  *
  63  * Return 1 if constructed; otherwise, return 0.
  64  * Note that we are in the responder's side of the QP context.
  65  * Note the QP s_lock must be held.
  66  */
  67 static int qib_make_rc_ack(struct qib_ibdev *dev, struct rvt_qp *qp,
  68                            struct ib_other_headers *ohdr, u32 pmtu)
  69 {
  70         struct rvt_ack_entry *e;
  71         u32 hwords;
  72         u32 len;
  73         u32 bth0;
  74         u32 bth2;
  75
  76         /* Don't send an ACK if we aren't supposed to. */
  77         if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK))
  78                 goto bail;
  79
  80         /* header size in 32-bit words LRH+BTH = (8+12)/4. */
  81         hwords = 5;
  82
  83         switch (qp->s_ack_state) {
  84         case OP(RDMA_READ_RESPONSE_LAST):
  85         case OP(RDMA_READ_RESPONSE_ONLY):
  86                 e = &qp->s_ack_queue[qp->s_tail_ack_queue];
  87                 if (e->rdma_sge.mr) {
  88                         rvt_put_mr(e->rdma_sge.mr);
  89                         e->rdma_sge.mr = NULL;
  90                 }
  91                 /* FALLTHROUGH */
  92         case OP(ATOMIC_ACKNOWLEDGE):
  93                 /*
  94                  * We can increment the tail pointer now that the last
  95                  * response has been sent instead of only being
  96                  * constructed.
  97                  */
  98                 if (++qp->s_tail_ack_queue > QIB_MAX_RDMA_ATOMIC)
  99                         qp->s_tail_ack_queue = 0;
 100                 /* FALLTHROUGH */
 101         case OP(SEND_ONLY):
 102         case OP(ACKNOWLEDGE):
 103                 /* Check for no next entry in the queue. */
 104                 if (qp->r_head_ack_queue == qp->s_tail_ack_queue) {
 105                         if (qp->s_flags & RVT_S_ACK_PENDING)
 106                                 goto normal;
 107                         goto bail;
 108                 }
 109
 110                 e = &qp->s_ack_queue[qp->s_tail_ack_queue];
 111                 if (e->opcode == OP(RDMA_READ_REQUEST)) {
 112                         /*
 113                          * If a RDMA read response is being resent and
 114                          * we haven't seen the duplicate request yet,
 115                          * then stop sending the remaining responses the
 116                          * responder has seen until the requester resends it.
 117                          */
 118                         len = e->rdma_sge.sge_length;
 119                         if (len && !e->rdma_sge.mr) {
 120                                 qp->s_tail_ack_queue = qp->r_head_ack_queue;
 121                                 goto bail;
 122                         }
 123                         /* Copy SGE state in case we need to resend */
 124                         qp->s_rdma_mr = e->rdma_sge.mr;
 125                         if (qp->s_rdma_mr)
 126                                 rvt_get_mr(qp->s_rdma_mr);
 127                         qp->s_ack_rdma_sge.sge = e->rdma_sge;
 128                         qp->s_ack_rdma_sge.num_sge = 1;
 129                         qp->s_cur_sge = &qp->s_ack_rdma_sge;
 130                         if (len > pmtu) {
 131                                 len = pmtu;
 132                                 qp->s_ack_state = OP(RDMA_READ_RESPONSE_FIRST);
 133                         } else {
 134                                 qp->s_ack_state = OP(RDMA_READ_RESPONSE_ONLY);
 135                                 e->sent = 1;
 136                         }
 137                         ohdr->u.aeth = rvt_compute_aeth(qp);
 138                         hwords++;
 139                         qp->s_ack_rdma_psn = e->psn;
 140                         bth2 = qp->s_ack_rdma_psn++ & QIB_PSN_MASK;
 141                 } else {
 142                         /* COMPARE_SWAP or FETCH_ADD */
 143                         qp->s_cur_sge = NULL;
 144                         len = 0;
 145                         qp->s_ack_state = OP(ATOMIC_ACKNOWLEDGE);
 146                         ohdr->u.at.aeth = rvt_compute_aeth(qp);
 147                         ib_u64_put(e->atomic_data, &ohdr->u.at.atomic_ack_eth);
 148                         hwords += sizeof(ohdr->u.at) / sizeof(u32);
 149                         bth2 = e->psn & QIB_PSN_MASK;
 150                         e->sent = 1;
 151                 }
 152                 bth0 = qp->s_ack_state << 24;
 153                 break;
 154
 155         case OP(RDMA_READ_RESPONSE_FIRST):
 156                 qp->s_ack_state = OP(RDMA_READ_RESPONSE_MIDDLE);
 157                 /* FALLTHROUGH */
 158         case OP(RDMA_READ_RESPONSE_MIDDLE):
 159                 qp->s_cur_sge = &qp->s_ack_rdma_sge;
 160                 qp->s_rdma_mr = qp->s_ack_rdma_sge.sge.mr;
 161                 if (qp->s_rdma_mr)
 162                         rvt_get_mr(qp->s_rdma_mr);
 163                 len = qp->s_ack_rdma_sge.sge.sge_length;
 164                 if (len > pmtu)
 165                         len = pmtu;
 166                 else {
 167                         ohdr->u.aeth = rvt_compute_aeth(qp);
 168                         hwords++;
 169                         qp->s_ack_state = OP(RDMA_READ_RESPONSE_LAST);
 170                         e = &qp->s_ack_queue[qp->s_tail_ack_queue];
 171                         e->sent = 1;
 172                 }
 173                 bth0 = qp->s_ack_state << 24;
 174                 bth2 = qp->s_ack_rdma_psn++ & QIB_PSN_MASK;
 175                 break;
 176
 177         default:
 178 normal:
 179                 /*
 180                  * Send a regular ACK.
 181                  * Set the s_ack_state so we wait until after sending
 182                  * the ACK before setting s_ack_state to ACKNOWLEDGE
 183                  * (see above).
 184                  */
 185                 qp->s_ack_state = OP(SEND_ONLY);
 186                 qp->s_flags &= ~RVT_S_ACK_PENDING;
 187                 qp->s_cur_sge = NULL;
 188                 if (qp->s_nak_state)
 189                         ohdr->u.aeth =
 190                                 cpu_to_be32((qp->r_msn & IB_MSN_MASK) |
 191                                             (qp->s_nak_state <<
 192                                              IB_AETH_CREDIT_SHIFT));
 193                 else
 194                         ohdr->u.aeth = rvt_compute_aeth(qp);
 195                 hwords++;
 196                 len = 0;
 197                 bth0 = OP(ACKNOWLEDGE) << 24;
 198                 bth2 = qp->s_ack_psn & QIB_PSN_MASK;
 199         }
 200         qp->s_rdma_ack_cnt++;
 201         qp->s_hdrwords = hwords;
 202         qp->s_cur_size = len;
 203         qib_make_ruc_header(qp, ohdr, bth0, bth2);
 204         return 1;
 205
 206 bail:
 207         qp->s_ack_state = OP(ACKNOWLEDGE);
 208         qp->s_flags &= ~(RVT_S_RESP_PENDING | RVT_S_ACK_PENDING);
 209         return 0;
 210 }
 211
 212 /**
 213  * qib_make_rc_req - construct a request packet (SEND, RDMA r/w, ATOMIC)
 214  * @qp: a pointer to the QP
 215  *
 216  * Assumes the s_lock is held.
 217  *
 218  * Return 1 if constructed; otherwise, return 0.
 219  */
 220 int qib_make_rc_req(struct rvt_qp *qp, unsigned long *flags)
 221 {
 222         struct qib_qp_priv *priv = qp->priv;
 223         struct qib_ibdev *dev = to_idev(qp->ibqp.device);
 224         struct ib_other_headers *ohdr;
 225         struct rvt_sge_state *ss;
 226         struct rvt_swqe *wqe;
 227         u32 hwords;
 228         u32 len;
 229         u32 bth0;
 230         u32 bth2;
 231         u32 pmtu = qp->pmtu;
 232         char newreq;
 233         int ret = 0;
 234         int delta;
 235
 236         ohdr = &priv->s_hdr->u.oth;
 237         if (rdma_ah_get_ah_flags(&qp->remote_ah_attr) & IB_AH_GRH)
 238                 ohdr = &priv->s_hdr->u.l.oth;
 239
 240         /* Sending responses has higher priority over sending requests. */
 241         if ((qp->s_flags & RVT_S_RESP_PENDING) &&
 242             qib_make_rc_ack(dev, qp, ohdr, pmtu))
 243                 goto done;
 244
 245         if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_SEND_OK)) {
 246                 if (!(ib_rvt_state_ops[qp->state] & RVT_FLUSH_SEND))
 247                         goto bail;
 248                 /* We are in the error state, flush the work request. */
 249                 smp_read_barrier_depends(); /* see post_one_send() */
 250                 if (qp->s_last == READ_ONCE(qp->s_head))
 251                         goto bail;
 252                 /* If DMAs are in progress, we can't flush immediately. */
 253                 if (atomic_read(&priv->s_dma_busy)) {
 254                         qp->s_flags |= RVT_S_WAIT_DMA;
 255                         goto bail;
 256                 }
 257                 wqe = rvt_get_swqe_ptr(qp, qp->s_last);
 258                 qib_send_complete(qp, wqe, qp->s_last != qp->s_acked ?
 259                         IB_WC_SUCCESS : IB_WC_WR_FLUSH_ERR);
 260                 /* will get called again */
 261                 goto done;
 262         }
 263
 264         if (qp->s_flags & (RVT_S_WAIT_RNR | RVT_S_WAIT_ACK))
 265                 goto bail;
 266
 267         if (qib_cmp24(qp->s_psn, qp->s_sending_hpsn) <= 0) {
 268                 if (qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) <= 0) {
 269                         qp->s_flags |= RVT_S_WAIT_PSN;
 270                         goto bail;
 271                 }
 272                 qp->s_sending_psn = qp->s_psn;
 273                 qp->s_sending_hpsn = qp->s_psn - 1;
 274         }
 275
 276         /* header size in 32-bit words LRH+BTH = (8+12)/4. */
 277         hwords = 5;
 278         bth0 = 0;
 279
 280         /* Send a request. */
 281         wqe = rvt_get_swqe_ptr(qp, qp->s_cur);
 282         switch (qp->s_state) {
 283         default:
 284                 if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_NEXT_SEND_OK))
 285                         goto bail;
 286                 /*
 287                  * Resend an old request or start a new one.
 288                  *
 289                  * We keep track of the current SWQE so that
 290                  * we don't reset the "furthest progress" state
 291                  * if we need to back up.
 292                  */
 293                 newreq = 0;
 294                 if (qp->s_cur == qp->s_tail) {
 295                         /* Check if send work queue is empty. */
 296                         smp_read_barrier_depends(); /* see post_one_send() */
 297                         if (qp->s_tail == READ_ONCE(qp->s_head))
 298                                 goto bail;
 299                         /*
 300                          * If a fence is requested, wait for previous
 301                          * RDMA read and atomic operations to finish.
 302                          */
 303                         if ((wqe->wr.send_flags & IB_SEND_FENCE) &&
 304                             qp->s_num_rd_atomic) {
 305                                 qp->s_flags |= RVT_S_WAIT_FENCE;
 306                                 goto bail;
 307                         }
 308                         newreq = 1;
 309                         qp->s_psn = wqe->psn;
 310                 }
 311                 /*
 312                  * Note that we have to be careful not to modify the
 313                  * original work request since we may need to resend
 314                  * it.
 315                  */
 316                 len = wqe->length;
 317                 ss = &qp->s_sge;
 318                 bth2 = qp->s_psn & QIB_PSN_MASK;
 319                 switch (wqe->wr.opcode) {
 320                 case IB_WR_SEND:
 321                 case IB_WR_SEND_WITH_IMM:
 322                         /* If no credit, return. */
 323                         if (!(qp->s_flags & RVT_S_UNLIMITED_CREDIT) &&
 324                             rvt_cmp_msn(wqe->ssn, qp->s_lsn + 1) > 0) {
 325                                 qp->s_flags |= RVT_S_WAIT_SSN_CREDIT;
 326                                 goto bail;
 327                         }
 328                         if (len > pmtu) {
 329                                 qp->s_state = OP(SEND_FIRST);
 330                                 len = pmtu;
 331                                 break;
 332                         }
 333                         if (wqe->wr.opcode == IB_WR_SEND)
 334                                 qp->s_state = OP(SEND_ONLY);
 335                         else {
 336                                 qp->s_state = OP(SEND_ONLY_WITH_IMMEDIATE);
 337                                 /* Immediate data comes after the BTH */
 338                                 ohdr->u.imm_data = wqe->wr.ex.imm_data;
 339                                 hwords += 1;
 340                         }
 341                         if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 342                                 bth0 |= IB_BTH_SOLICITED;
 343                         bth2 |= IB_BTH_REQ_ACK;
 344                         if (++qp->s_cur == qp->s_size)
 345                                 qp->s_cur = 0;
 346                         break;
 347
 348                 case IB_WR_RDMA_WRITE:
 349                         if (newreq && !(qp->s_flags & RVT_S_UNLIMITED_CREDIT))
 350                                 qp->s_lsn++;
 351                         /* FALLTHROUGH */
 352                 case IB_WR_RDMA_WRITE_WITH_IMM:
 353                         /* If no credit, return. */
 354                         if (!(qp->s_flags & RVT_S_UNLIMITED_CREDIT) &&
 355                             rvt_cmp_msn(wqe->ssn, qp->s_lsn + 1) > 0) {
 356                                 qp->s_flags |= RVT_S_WAIT_SSN_CREDIT;
 357                                 goto bail;
 358                         }
 359
 360                         ohdr->u.rc.reth.vaddr =
 361                                 cpu_to_be64(wqe->rdma_wr.remote_addr);
 362                         ohdr->u.rc.reth.rkey =
 363                                 cpu_to_be32(wqe->rdma_wr.rkey);
 364                         ohdr->u.rc.reth.length = cpu_to_be32(len);
 365                         hwords += sizeof(struct ib_reth) / sizeof(u32);
 366                         if (len > pmtu) {
 367                                 qp->s_state = OP(RDMA_WRITE_FIRST);
 368                                 len = pmtu;
 369                                 break;
 370                         }
 371                         if (wqe->rdma_wr.wr.opcode == IB_WR_RDMA_WRITE)
 372                                 qp->s_state = OP(RDMA_WRITE_ONLY);
 373                         else {
 374                                 qp->s_state = OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE);
 375                                 /* Immediate data comes after RETH */
 376                                 ohdr->u.rc.imm_data =
 377                                         wqe->rdma_wr.wr.ex.imm_data;
 378                                 hwords += 1;
 379                                 if (wqe->rdma_wr.wr.send_flags & IB_SEND_SOLICITED)
 380                                         bth0 |= IB_BTH_SOLICITED;
 381                         }
 382                         bth2 |= IB_BTH_REQ_ACK;
 383                         if (++qp->s_cur == qp->s_size)
 384                                 qp->s_cur = 0;
 385                         break;
 386
 387                 case IB_WR_RDMA_READ:
 388                         /*
 389                          * Don't allow more operations to be started
 390                          * than the QP limits allow.
 391                          */
 392                         if (newreq) {
 393                                 if (qp->s_num_rd_atomic >=
 394                                     qp->s_max_rd_atomic) {
 395                                         qp->s_flags |= RVT_S_WAIT_RDMAR;
 396                                         goto bail;
 397                                 }
 398                                 qp->s_num_rd_atomic++;
 399                                 if (!(qp->s_flags & RVT_S_UNLIMITED_CREDIT))
 400                                         qp->s_lsn++;
 401                         }
 402
 403                         ohdr->u.rc.reth.vaddr =
 404                                 cpu_to_be64(wqe->rdma_wr.remote_addr);
 405                         ohdr->u.rc.reth.rkey =
 406                                 cpu_to_be32(wqe->rdma_wr.rkey);
 407                         ohdr->u.rc.reth.length = cpu_to_be32(len);
 408                         qp->s_state = OP(RDMA_READ_REQUEST);
 409                         hwords += sizeof(ohdr->u.rc.reth) / sizeof(u32);
 410                         ss = NULL;
 411                         len = 0;
 412                         bth2 |= IB_BTH_REQ_ACK;
 413                         if (++qp->s_cur == qp->s_size)
 414                                 qp->s_cur = 0;
 415                         break;
 416
 417                 case IB_WR_ATOMIC_CMP_AND_SWP:
 418                 case IB_WR_ATOMIC_FETCH_AND_ADD:
 419                         /*
 420                          * Don't allow more operations to be started
 421                          * than the QP limits allow.
 422                          */
 423                         if (newreq) {
 424                                 if (qp->s_num_rd_atomic >=
 425                                     qp->s_max_rd_atomic) {
 426                                         qp->s_flags |= RVT_S_WAIT_RDMAR;
 427                                         goto bail;
 428                                 }
 429                                 qp->s_num_rd_atomic++;
 430                                 if (!(qp->s_flags & RVT_S_UNLIMITED_CREDIT))
 431                                         qp->s_lsn++;
 432                         }
 433                         if (wqe->atomic_wr.wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP) {
 434                                 qp->s_state = OP(COMPARE_SWAP);
 435                                 put_ib_ateth_swap(wqe->atomic_wr.swap,
 436                                                   &ohdr->u.atomic_eth);
 437                                 put_ib_ateth_swap(wqe->atomic_wr.compare_add,
 438                                                   &ohdr->u.atomic_eth);
 439                         } else {
 440                                 qp->s_state = OP(FETCH_ADD);
 441                                 put_ib_ateth_swap(wqe->atomic_wr.compare_add,
 442                                                   &ohdr->u.atomic_eth);
 443                                 put_ib_ateth_swap(0, &ohdr->u.atomic_eth);
 444                         }
 445                         put_ib_ateth_vaddr(wqe->atomic_wr.remote_addr,
 446                                            &ohdr->u.atomic_eth);
 447                         ohdr->u.atomic_eth.rkey = cpu_to_be32(
 448                                 wqe->atomic_wr.rkey);
 449                         hwords += sizeof(struct ib_atomic_eth) / sizeof(u32);
 450                         ss = NULL;
 451                         len = 0;
 452                         bth2 |= IB_BTH_REQ_ACK;
 453                         if (++qp->s_cur == qp->s_size)
 454                                 qp->s_cur = 0;
 455                         break;
 456
 457                 default:
 458                         goto bail;
 459                 }
 460                 qp->s_sge.sge = wqe->sg_list[0];
 461                 qp->s_sge.sg_list = wqe->sg_list + 1;
 462                 qp->s_sge.num_sge = wqe->wr.num_sge;
 463                 qp->s_sge.total_len = wqe->length;
 464                 qp->s_len = wqe->length;
 465                 if (newreq) {
 466                         qp->s_tail++;
 467                         if (qp->s_tail >= qp->s_size)
 468                                 qp->s_tail = 0;
 469                 }
 470                 if (wqe->wr.opcode == IB_WR_RDMA_READ)
 471                         qp->s_psn = wqe->lpsn + 1;
 472                 else
 473                         qp->s_psn++;
 474                 break;
 475
 476         case OP(RDMA_READ_RESPONSE_FIRST):
 477                 /*
 478                  * qp->s_state is normally set to the opcode of the
 479                  * last packet constructed for new requests and therefore
 480                  * is never set to RDMA read response.
 481                  * RDMA_READ_RESPONSE_FIRST is used by the ACK processing
 482                  * thread to indicate a SEND needs to be restarted from an
 483                  * earlier PSN without interferring with the sending thread.
 484                  * See qib_restart_rc().
 485                  */
 486                 qp->s_len = restart_sge(&qp->s_sge, wqe, qp->s_psn, pmtu);
 487                 /* FALLTHROUGH */
 488         case OP(SEND_FIRST):
 489                 qp->s_state = OP(SEND_MIDDLE);
 490                 /* FALLTHROUGH */
 491         case OP(SEND_MIDDLE):
 492                 bth2 = qp->s_psn++ & QIB_PSN_MASK;
 493                 ss = &qp->s_sge;
 494                 len = qp->s_len;
 495                 if (len > pmtu) {
 496                         len = pmtu;
 497                         break;
 498                 }
 499                 if (wqe->wr.opcode == IB_WR_SEND)
 500                         qp->s_state = OP(SEND_LAST);
 501                 else {
 502                         qp->s_state = OP(SEND_LAST_WITH_IMMEDIATE);
 503                         /* Immediate data comes after the BTH */
 504                         ohdr->u.imm_data = wqe->wr.ex.imm_data;
 505                         hwords += 1;
 506                 }
 507                 if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 508                         bth0 |= IB_BTH_SOLICITED;
 509                 bth2 |= IB_BTH_REQ_ACK;
 510                 qp->s_cur++;
 511                 if (qp->s_cur >= qp->s_size)
 512                         qp->s_cur = 0;
 513                 break;
 514
 515         case OP(RDMA_READ_RESPONSE_LAST):
 516                 /*
 517                  * qp->s_state is normally set to the opcode of the
 518                  * last packet constructed for new requests and therefore
 519                  * is never set to RDMA read response.
 520                  * RDMA_READ_RESPONSE_LAST is used by the ACK processing
 521                  * thread to indicate a RDMA write needs to be restarted from
 522                  * an earlier PSN without interferring with the sending thread.
 523                  * See qib_restart_rc().
 524                  */
 525                 qp->s_len = restart_sge(&qp->s_sge, wqe, qp->s_psn, pmtu);
 526                 /* FALLTHROUGH */
 527         case OP(RDMA_WRITE_FIRST):
 528                 qp->s_state = OP(RDMA_WRITE_MIDDLE);
 529                 /* FALLTHROUGH */
 530         case OP(RDMA_WRITE_MIDDLE):
 531                 bth2 = qp->s_psn++ & QIB_PSN_MASK;
 532                 ss = &qp->s_sge;
 533                 len = qp->s_len;
 534                 if (len > pmtu) {
 535                         len = pmtu;
 536                         break;
 537                 }
 538                 if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
 539                         qp->s_state = OP(RDMA_WRITE_LAST);
 540                 else {
 541                         qp->s_state = OP(RDMA_WRITE_LAST_WITH_IMMEDIATE);
 542                         /* Immediate data comes after the BTH */
 543                         ohdr->u.imm_data = wqe->wr.ex.imm_data;
 544                         hwords += 1;
 545                         if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 546                                 bth0 |= IB_BTH_SOLICITED;
 547                 }
 548                 bth2 |= IB_BTH_REQ_ACK;
 549                 qp->s_cur++;
 550                 if (qp->s_cur >= qp->s_size)
 551                         qp->s_cur = 0;
 552                 break;
 553
 554         case OP(RDMA_READ_RESPONSE_MIDDLE):
 555                 /*
 556                  * qp->s_state is normally set to the opcode of the
 557                  * last packet constructed for new requests and therefore
 558                  * is never set to RDMA read response.
 559                  * RDMA_READ_RESPONSE_MIDDLE is used by the ACK processing
 560                  * thread to indicate a RDMA read needs to be restarted from
 561                  * an earlier PSN without interferring with the sending thread.
 562                  * See qib_restart_rc().
 563                  */
 564                 len = ((qp->s_psn - wqe->psn) & QIB_PSN_MASK) * pmtu;
 565                 ohdr->u.rc.reth.vaddr =
 566                         cpu_to_be64(wqe->rdma_wr.remote_addr + len);
 567                 ohdr->u.rc.reth.rkey =
 568                         cpu_to_be32(wqe->rdma_wr.rkey);
 569                 ohdr->u.rc.reth.length = cpu_to_be32(wqe->length - len);
 570                 qp->s_state = OP(RDMA_READ_REQUEST);
 571                 hwords += sizeof(ohdr->u.rc.reth) / sizeof(u32);
 572                 bth2 = (qp->s_psn & QIB_PSN_MASK) | IB_BTH_REQ_ACK;
 573                 qp->s_psn = wqe->lpsn + 1;
 574                 ss = NULL;
 575                 len = 0;
 576                 qp->s_cur++;
 577                 if (qp->s_cur == qp->s_size)
 578                         qp->s_cur = 0;
 579                 break;
 580         }
 581         qp->s_sending_hpsn = bth2;
 582         delta = (((int) bth2 - (int) wqe->psn) << 8) >> 8;
 583         if (delta && delta % QIB_PSN_CREDIT == 0)
 584                 bth2 |= IB_BTH_REQ_ACK;
 585         if (qp->s_flags & RVT_S_SEND_ONE) {
 586                 qp->s_flags &= ~RVT_S_SEND_ONE;
 587                 qp->s_flags |= RVT_S_WAIT_ACK;
 588                 bth2 |= IB_BTH_REQ_ACK;
 589         }
 590         qp->s_len -= len;
 591         qp->s_hdrwords = hwords;
 592         qp->s_cur_sge = ss;
 593         qp->s_cur_size = len;
 594         qib_make_ruc_header(qp, ohdr, bth0 | (qp->s_state << 24), bth2);
 595 done:
 596         return 1;
 597 bail:
 598         qp->s_flags &= ~RVT_S_BUSY;
 599         return ret;
 600 }
 601
 602 /**
 603  * qib_send_rc_ack - Construct an ACK packet and send it
 604  * @qp: a pointer to the QP
 605  *
 606  * This is called from qib_rc_rcv() and qib_kreceive().
 607  * Note that RDMA reads and atomics are handled in the
 608  * send side QP state and tasklet.
 609  */
 610 void qib_send_rc_ack(struct rvt_qp *qp)
 611 {
 612         struct qib_devdata *dd = dd_from_ibdev(qp->ibqp.device);
 613         struct qib_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
 614         struct qib_pportdata *ppd = ppd_from_ibp(ibp);
 615         u64 pbc;
 616         u16 lrh0;
 617         u32 bth0;
 618         u32 hwords;
 619         u32 pbufn;
 620         u32 __iomem *piobuf;
 621         struct ib_header hdr;
 622         struct ib_other_headers *ohdr;
 623         u32 control;
 624         unsigned long flags;
 625
 626         spin_lock_irqsave(&qp->s_lock, flags);
 627
 628         if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK))
 629                 goto unlock;
 630
 631         /* Don't send ACK or NAK if a RDMA read or atomic is pending. */
 632         if ((qp->s_flags & RVT_S_RESP_PENDING) || qp->s_rdma_ack_cnt)
 633                 goto queue_ack;
 634
 635         /* Construct the header with s_lock held so APM doesn't change it. */
 636         ohdr = &hdr.u.oth;
 637         lrh0 = QIB_LRH_BTH;
 638         /* header size in 32-bit words LRH+BTH+AETH = (8+12+4)/4. */
 639         hwords = 6;
 640         if (unlikely(rdma_ah_get_ah_flags(&qp->remote_ah_attr) &
 641                      IB_AH_GRH)) {
 642                 hwords += qib_make_grh(ibp, &hdr.u.l.grh,
 643                                        rdma_ah_read_grh(&qp->remote_ah_attr),
 644                                        hwords, 0);
 645                 ohdr = &hdr.u.l.oth;
 646                 lrh0 = QIB_LRH_GRH;
 647         }
 648         /* read pkey_index w/o lock (its atomic) */
 649         bth0 = qib_get_pkey(ibp, qp->s_pkey_index) | (OP(ACKNOWLEDGE) << 24);
 650         if (qp->s_mig_state == IB_MIG_MIGRATED)
 651                 bth0 |= IB_BTH_MIG_REQ;
 652         if (qp->r_nak_state)
 653                 ohdr->u.aeth = cpu_to_be32((qp->r_msn & IB_MSN_MASK) |
 654                                             (qp->r_nak_state <<
 655                                              IB_AETH_CREDIT_SHIFT));
 656         else
 657                 ohdr->u.aeth = rvt_compute_aeth(qp);
 658         lrh0 |= ibp->sl_to_vl[rdma_ah_get_sl(&qp->remote_ah_attr)] << 12 |
 659                 rdma_ah_get_sl(&qp->remote_ah_attr) << 4;
 660         hdr.lrh[0] = cpu_to_be16(lrh0);
 661         hdr.lrh[1] = cpu_to_be16(rdma_ah_get_dlid(&qp->remote_ah_attr));
 662         hdr.lrh[2] = cpu_to_be16(hwords + SIZE_OF_CRC);
 663         hdr.lrh[3] = cpu_to_be16(ppd->lid |
 664                                  rdma_ah_get_path_bits(&qp->remote_ah_attr));
 665         ohdr->bth[0] = cpu_to_be32(bth0);
 666         ohdr->bth[1] = cpu_to_be32(qp->remote_qpn);
 667         ohdr->bth[2] = cpu_to_be32(qp->r_ack_psn & QIB_PSN_MASK);
 668
 669         spin_unlock_irqrestore(&qp->s_lock, flags);
 670
 671         /* Don't try to send ACKs if the link isn't ACTIVE */
 672         if (!(ppd->lflags & QIBL_LINKACTIVE))
 673                 goto done;
 674
 675         control = dd->f_setpbc_control(ppd, hwords + SIZE_OF_CRC,
 676                                        qp->s_srate, lrh0 >> 12);
 677         /* length is + 1 for the control dword */
 678         pbc = ((u64) control << 32) | (hwords + 1);
 679
 680         piobuf = dd->f_getsendbuf(ppd, pbc, &pbufn);
 681         if (!piobuf) {
 682                 /*
 683                  * We are out of PIO buffers at the moment.
 684                  * Pass responsibility for sending the ACK to the
 685                  * send tasklet so that when a PIO buffer becomes
 686                  * available, the ACK is sent ahead of other outgoing
 687                  * packets.
 688                  */
 689                 spin_lock_irqsave(&qp->s_lock, flags);
 690                 goto queue_ack;
 691         }
 692
 693         /*
 694          * Write the pbc.
 695          * We have to flush after the PBC for correctness
 696          * on some cpus or WC buffer can be written out of order.
 697          */
 698         writeq(pbc, piobuf);
 699
 700         if (dd->flags & QIB_PIO_FLUSH_WC) {
 701                 u32 *hdrp = (u32 *) &hdr;
 702
 703                 qib_flush_wc();
 704                 qib_pio_copy(piobuf + 2, hdrp, hwords - 1);
 705                 qib_flush_wc();
 706                 __raw_writel(hdrp[hwords - 1], piobuf + hwords + 1);
 707         } else
 708                 qib_pio_copy(piobuf + 2, (u32 *) &hdr, hwords);
 709
 710         if (dd->flags & QIB_USE_SPCL_TRIG) {
 711                 u32 spcl_off = (pbufn >= dd->piobcnt2k) ? 2047 : 1023;
 712
 713                 qib_flush_wc();
 714                 __raw_writel(0xaebecede, piobuf + spcl_off);
 715         }
 716
 717         qib_flush_wc();
 718         qib_sendbuf_done(dd, pbufn);
 719
 720         this_cpu_inc(ibp->pmastats->n_unicast_xmit);
 721         goto done;
 722
 723 queue_ack:
 724         if (ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK) {
 725                 this_cpu_inc(*ibp->rvp.rc_qacks);
 726                 qp->s_flags |= RVT_S_ACK_PENDING | RVT_S_RESP_PENDING;
 727                 qp->s_nak_state = qp->r_nak_state;
 728                 qp->s_ack_psn = qp->r_ack_psn;
 729
 730                 /* Schedule the send tasklet. */
 731                 qib_schedule_send(qp);
 732         }
 733 unlock:
 734         spin_unlock_irqrestore(&qp->s_lock, flags);
 735 done:
 736         return;
 737 }
 738
 739 /**
 740  * reset_psn - reset the QP state to send starting from PSN
 741  * @qp: the QP
 742  * @psn: the packet sequence number to restart at
 743  *
 744  * This is called from qib_rc_rcv() to process an incoming RC ACK
 745  * for the given QP.
 746  * Called at interrupt level with the QP s_lock held.
 747  */
 748 static void reset_psn(struct rvt_qp *qp, u32 psn)
 749 {
 750         u32 n = qp->s_acked;
 751         struct rvt_swqe *wqe = rvt_get_swqe_ptr(qp, n);
 752         u32 opcode;
 753
 754         qp->s_cur = n;
 755
 756         /*
 757          * If we are starting the request from the beginning,
 758          * let the normal send code handle initialization.
 759          */
 760         if (qib_cmp24(psn, wqe->psn) <= 0) {
 761                 qp->s_state = OP(SEND_LAST);
 762                 goto done;
 763         }
 764
 765         /* Find the work request opcode corresponding to the given PSN. */
 766         opcode = wqe->wr.opcode;
 767         for (;;) {
 768                 int diff;
 769
 770                 if (++n == qp->s_size)
 771                         n = 0;
 772                 if (n == qp->s_tail)
 773                         break;
 774                 wqe = rvt_get_swqe_ptr(qp, n);
 775                 diff = qib_cmp24(psn, wqe->psn);
 776                 if (diff < 0)
 777                         break;
 778                 qp->s_cur = n;
 779                 /*
 780                  * If we are starting the request from the beginning,
 781                  * let the normal send code handle initialization.
 782                  */
 783                 if (diff == 0) {
 784                         qp->s_state = OP(SEND_LAST);
 785                         goto done;
 786                 }
 787                 opcode = wqe->wr.opcode;
 788         }
 789
 790         /*
 791          * Set the state to restart in the middle of a request.
 792          * Don't change the s_sge, s_cur_sge, or s_cur_size.
 793          * See qib_make_rc_req().
 794          */
 795         switch (opcode) {
 796         case IB_WR_SEND:
 797         case IB_WR_SEND_WITH_IMM:
 798                 qp->s_state = OP(RDMA_READ_RESPONSE_FIRST);
 799                 break;
 800
 801         case IB_WR_RDMA_WRITE:
 802         case IB_WR_RDMA_WRITE_WITH_IMM:
 803                 qp->s_state = OP(RDMA_READ_RESPONSE_LAST);
 804                 break;
 805
 806         case IB_WR_RDMA_READ:
 807                 qp->s_state = OP(RDMA_READ_RESPONSE_MIDDLE);
 808                 break;
 809
 810         default:
 811                 /*
 812                  * This case shouldn't happen since its only
 813                  * one PSN per req.
 814                  */
 815                 qp->s_state = OP(SEND_LAST);
 816         }
 817 done:
 818         qp->s_psn = psn;
 819         /*
 820          * Set RVT_S_WAIT_PSN as qib_rc_complete() may start the timer
 821          * asynchronously before the send tasklet can get scheduled.
 822          * Doing it in qib_make_rc_req() is too late.
 823          */
 824         if ((qib_cmp24(qp->s_psn, qp->s_sending_hpsn) <= 0) &&
 825             (qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) <= 0))
 826                 qp->s_flags |= RVT_S_WAIT_PSN;
 827 }
 828
 829 /*
 830  * Back up requester to resend the last un-ACKed request.
 831  * The QP r_lock and s_lock should be held and interrupts disabled.
 832  */
 833 void qib_restart_rc(struct rvt_qp *qp, u32 psn, int wait)
 834 {
 835         struct rvt_swqe *wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
 836         struct qib_ibport *ibp;
 837
 838         if (qp->s_retry == 0) {
 839                 if (qp->s_mig_state == IB_MIG_ARMED) {
 840                         qib_migrate_qp(qp);
 841                         qp->s_retry = qp->s_retry_cnt;
 842                 } else if (qp->s_last == qp->s_acked) {
 843                         qib_send_complete(qp, wqe, IB_WC_RETRY_EXC_ERR);
 844                         rvt_error_qp(qp, IB_WC_WR_FLUSH_ERR);
 845                         return;
 846                 } else /* XXX need to handle delayed completion */
 847                         return;
 848         } else
 849                 qp->s_retry--;
 850
 851         ibp = to_iport(qp->ibqp.device, qp->port_num);
 852         if (wqe->wr.opcode == IB_WR_RDMA_READ)
 853                 ibp->rvp.n_rc_resends++;
 854         else
 855                 ibp->rvp.n_rc_resends += (qp->s_psn - psn) & QIB_PSN_MASK;
 856
 857         qp->s_flags &= ~(RVT_S_WAIT_FENCE | RVT_S_WAIT_RDMAR |
 858                          RVT_S_WAIT_SSN_CREDIT | RVT_S_WAIT_PSN |
 859                          RVT_S_WAIT_ACK);
 860         if (wait)
 861                 qp->s_flags |= RVT_S_SEND_ONE;
 862         reset_psn(qp, psn);
 863 }
 864
 865 /*
 866  * Set qp->s_sending_psn to the next PSN after the given one.
 867  * This would be psn+1 except when RDMA reads are present.
 868  */
 869 static void reset_sending_psn(struct rvt_qp *qp, u32 psn)
 870 {
 871         struct rvt_swqe *wqe;
 872         u32 n = qp->s_last;
 873
 874         /* Find the work request corresponding to the given PSN. */
 875         for (;;) {
 876                 wqe = rvt_get_swqe_ptr(qp, n);
 877                 if (qib_cmp24(psn, wqe->lpsn) <= 0) {
 878                         if (wqe->wr.opcode == IB_WR_RDMA_READ)
 879                                 qp->s_sending_psn = wqe->lpsn + 1;
 880                         else
 881                                 qp->s_sending_psn = psn + 1;
 882                         break;
 883                 }
 884                 if (++n == qp->s_size)
 885                         n = 0;
 886                 if (n == qp->s_tail)
 887                         break;
 888         }
 889 }
 890
 891 /*
 892  * This should be called with the QP s_lock held and interrupts disabled.
 893  */
 894 void qib_rc_send_complete(struct rvt_qp *qp, struct ib_header *hdr)
 895 {
 896         struct ib_other_headers *ohdr;
 897         struct rvt_swqe *wqe;
 898         u32 opcode;
 899         u32 psn;
 900
 901         if (!(ib_rvt_state_ops[qp->state] & RVT_SEND_OR_FLUSH_OR_RECV_OK))
 902                 return;
 903
 904         /* Find out where the BTH is */
 905         if ((be16_to_cpu(hdr->lrh[0]) & 3) == QIB_LRH_BTH)
 906                 ohdr = &hdr->u.oth;
 907         else
 908                 ohdr = &hdr->u.l.oth;
 909
 910         opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
 911         if (opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
 912             opcode <= OP(ATOMIC_ACKNOWLEDGE)) {
 913                 WARN_ON(!qp->s_rdma_ack_cnt);
 914                 qp->s_rdma_ack_cnt--;
 915                 return;
 916         }
 917
 918         psn = be32_to_cpu(ohdr->bth[2]);
 919         reset_sending_psn(qp, psn);
 920
 921         /*
 922          * Start timer after a packet requesting an ACK has been sent and
 923          * there are still requests that haven't been acked.
 924          */
 925         if ((psn & IB_BTH_REQ_ACK) && qp->s_acked != qp->s_tail &&
 926             !(qp->s_flags & (RVT_S_TIMER | RVT_S_WAIT_RNR | RVT_S_WAIT_PSN)) &&
 927             (ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK))
 928                 rvt_add_retry_timer(qp);
 929
 930         while (qp->s_last != qp->s_acked) {
 931                 u32 s_last;
 932
 933                 wqe = rvt_get_swqe_ptr(qp, qp->s_last);
 934                 if (qib_cmp24(wqe->lpsn, qp->s_sending_psn) >= 0 &&
 935                     qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) <= 0)
 936                         break;
 937                 s_last = qp->s_last;
 938                 if (++s_last >= qp->s_size)
 939                         s_last = 0;
 940                 qp->s_last = s_last;
 941                 /* see post_send() */
 942                 barrier();
 943                 rvt_put_swqe(wqe);
 944                 rvt_qp_swqe_complete(qp,
 945                                      wqe,
 946                                      ib_qib_wc_opcode[wqe->wr.opcode],
 947                                      IB_WC_SUCCESS);
 948         }
 949         /*
 950          * If we were waiting for sends to complete before resending,
 951          * and they are now complete, restart sending.
 952          */
 953         if (qp->s_flags & RVT_S_WAIT_PSN &&
 954             qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) > 0) {
 955                 qp->s_flags &= ~RVT_S_WAIT_PSN;
 956                 qp->s_sending_psn = qp->s_psn;
 957                 qp->s_sending_hpsn = qp->s_psn - 1;
 958                 qib_schedule_send(qp);
 959         }
 960 }
 961
 962 static inline void update_last_psn(struct rvt_qp *qp, u32 psn)
 963 {
 964         qp->s_last_psn = psn;
 965 }
 966
 967 /*
 968  * Generate a SWQE completion.
 969  * This is similar to qib_send_complete but has to check to be sure
 970  * that the SGEs are not being referenced if the SWQE is being resent.
 971  */
 972 static struct rvt_swqe *do_rc_completion(struct rvt_qp *qp,
 973                                          struct rvt_swqe *wqe,
 974                                          struct qib_ibport *ibp)
 975 {
 976         /*
 977          * Don't decrement refcount and don't generate a
 978          * completion if the SWQE is being resent until the send
 979          * is finished.
 980          */
 981         if (qib_cmp24(wqe->lpsn, qp->s_sending_psn) < 0 ||
 982             qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) > 0) {
 983                 u32 s_last;
 984
 985                 rvt_put_swqe(wqe);
 986                 s_last = qp->s_last;
 987                 if (++s_last >= qp->s_size)
 988                         s_last = 0;
 989                 qp->s_last = s_last;
 990                 /* see post_send() */
 991                 barrier();
 992                 rvt_qp_swqe_complete(qp,
 993                                      wqe,
 994                                      ib_qib_wc_opcode[wqe->wr.opcode],
 995                                      IB_WC_SUCCESS);
 996         } else
 997                 this_cpu_inc(*ibp->rvp.rc_delayed_comp);
 998
 999         qp->s_retry = qp->s_retry_cnt;
1000         update_last_psn(qp, wqe->lpsn);
1001
1002         /*
1003          * If we are completing a request which is in the process of
1004          * being resent, we can stop resending it since we know the
1005          * responder has already seen it.
1006          */
1007         if (qp->s_acked == qp->s_cur) {
1008                 if (++qp->s_cur >= qp->s_size)
1009                         qp->s_cur = 0;
1010                 qp->s_acked = qp->s_cur;
1011                 wqe = rvt_get_swqe_ptr(qp, qp->s_cur);
1012                 if (qp->s_acked != qp->s_tail) {
1013                         qp->s_state = OP(SEND_LAST);
1014                         qp->s_psn = wqe->psn;
1015                 }
1016         } else {
1017                 if (++qp->s_acked >= qp->s_size)
1018                         qp->s_acked = 0;
1019                 if (qp->state == IB_QPS_SQD && qp->s_acked == qp->s_cur)
1020                         qp->s_draining = 0;
1021                 wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1022         }
1023         return wqe;
1024 }
1025
1026 /**
1027  * do_rc_ack - process an incoming RC ACK
1028  * @qp: the QP the ACK came in on
1029  * @psn: the packet sequence number of the ACK
1030  * @opcode: the opcode of the request that resulted in the ACK
1031  *
1032  * This is called from qib_rc_rcv_resp() to process an incoming RC ACK
1033  * for the given QP.
1034  * Called at interrupt level with the QP s_lock held.
1035  * Returns 1 if OK, 0 if current operation should be aborted (NAK).
1036  */
1037 static int do_rc_ack(struct rvt_qp *qp, u32 aeth, u32 psn, int opcode,
1038                      u64 val, struct qib_ctxtdata *rcd)
1039 {
1040         struct qib_ibport *ibp;
1041         enum ib_wc_status status;
1042         struct rvt_swqe *wqe;
1043         int ret = 0;
1044         u32 ack_psn;
1045         int diff;
1046
1047         /*
1048          * Note that NAKs implicitly ACK outstanding SEND and RDMA write
1049          * requests and implicitly NAK RDMA read and atomic requests issued
1050          * before the NAK'ed request.  The MSN won't include the NAK'ed
1051          * request but will include an ACK'ed request(s).
1052          */
1053         ack_psn = psn;
1054         if (aeth >> IB_AETH_NAK_SHIFT)
1055                 ack_psn--;
1056         wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1057         ibp = to_iport(qp->ibqp.device, qp->port_num);
1058
1059         /*
1060          * The MSN might be for a later WQE than the PSN indicates so
1061          * only complete WQEs that the PSN finishes.
1062          */
1063         while ((diff = qib_cmp24(ack_psn, wqe->lpsn)) >= 0) {
1064                 /*
1065                  * RDMA_READ_RESPONSE_ONLY is a special case since
1066                  * we want to generate completion events for everything
1067                  * before the RDMA read, copy the data, then generate
1068                  * the completion for the read.
1069                  */
1070                 if (wqe->wr.opcode == IB_WR_RDMA_READ &&
1071                     opcode == OP(RDMA_READ_RESPONSE_ONLY) &&
1072                     diff == 0) {
1073                         ret = 1;
1074                         goto bail;
1075                 }
1076                 /*
1077                  * If this request is a RDMA read or atomic, and the ACK is
1078                  * for a later operation, this ACK NAKs the RDMA read or
1079                  * atomic.  In other words, only a RDMA_READ_LAST or ONLY
1080                  * can ACK a RDMA read and likewise for atomic ops.  Note
1081                  * that the NAK case can only happen if relaxed ordering is
1082                  * used and requests are sent after an RDMA read or atomic
1083                  * is sent but before the response is received.
1084                  */
1085                 if ((wqe->wr.opcode == IB_WR_RDMA_READ &&
1086                      (opcode != OP(RDMA_READ_RESPONSE_LAST) || diff != 0)) ||
1087                     ((wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1088                       wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) &&
1089                      (opcode != OP(ATOMIC_ACKNOWLEDGE) || diff != 0))) {
1090                         /* Retry this request. */
1091                         if (!(qp->r_flags & RVT_R_RDMAR_SEQ)) {
1092                                 qp->r_flags |= RVT_R_RDMAR_SEQ;
1093                                 qib_restart_rc(qp, qp->s_last_psn + 1, 0);
1094                                 if (list_empty(&qp->rspwait)) {
1095                                         qp->r_flags |= RVT_R_RSP_SEND;
1096                                         rvt_get_qp(qp);
1097                                         list_add_tail(&qp->rspwait,
1098                                                       &rcd->qp_wait_list);
1099                                 }
1100                         }
1101                         /*
1102                          * No need to process the ACK/NAK since we are
1103                          * restarting an earlier request.
1104                          */
1105                         goto bail;
1106                 }
1107                 if (wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1108                     wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) {
1109                         u64 *vaddr = wqe->sg_list[0].vaddr;
1110                         *vaddr = val;
1111                 }
1112                 if (qp->s_num_rd_atomic &&
1113                     (wqe->wr.opcode == IB_WR_RDMA_READ ||
1114                      wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1115                      wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)) {
1116                         qp->s_num_rd_atomic--;
1117                         /* Restart sending task if fence is complete */
1118                         if ((qp->s_flags & RVT_S_WAIT_FENCE) &&
1119                             !qp->s_num_rd_atomic) {
1120                                 qp->s_flags &= ~(RVT_S_WAIT_FENCE |
1121                                                  RVT_S_WAIT_ACK);
1122                                 qib_schedule_send(qp);
1123                         } else if (qp->s_flags & RVT_S_WAIT_RDMAR) {
1124                                 qp->s_flags &= ~(RVT_S_WAIT_RDMAR |
1125                                                  RVT_S_WAIT_ACK);
1126                                 qib_schedule_send(qp);
1127                         }
1128                 }
1129                 wqe = do_rc_completion(qp, wqe, ibp);
1130                 if (qp->s_acked == qp->s_tail)
1131                         break;
1132         }
1133
1134         switch (aeth >> IB_AETH_NAK_SHIFT) {
1135         case 0:         /* ACK */
1136                 this_cpu_inc(*ibp->rvp.rc_acks);
1137                 if (qp->s_acked != qp->s_tail) {
1138                         /*
1139                          * We are expecting more ACKs so
1140                          * reset the retransmit timer.
1141                          */
1142                         rvt_mod_retry_timer(qp);
1143                         /*
1144                          * We can stop resending the earlier packets and
1145                          * continue with the next packet the receiver wants.
1146                          */
1147                         if (qib_cmp24(qp->s_psn, psn) <= 0)
1148                                 reset_psn(qp, psn + 1);
1149                 } else {
1150                         /* No more acks - kill all timers */
1151                         rvt_stop_rc_timers(qp);
1152                         if (qib_cmp24(qp->s_psn, psn) <= 0) {
1153                                 qp->s_state = OP(SEND_LAST);
1154                                 qp->s_psn = psn + 1;
1155                         }
1156                 }
1157                 if (qp->s_flags & RVT_S_WAIT_ACK) {
1158                         qp->s_flags &= ~RVT_S_WAIT_ACK;
1159                         qib_schedule_send(qp);
1160                 }
1161                 rvt_get_credit(qp, aeth);
1162                 qp->s_rnr_retry = qp->s_rnr_retry_cnt;
1163                 qp->s_retry = qp->s_retry_cnt;
1164                 update_last_psn(qp, psn);
1165                 return 1;
1166
1167         case 1:         /* RNR NAK */
1168                 ibp->rvp.n_rnr_naks++;
1169                 if (qp->s_acked == qp->s_tail)
1170                         goto bail;
1171                 if (qp->s_flags & RVT_S_WAIT_RNR)
1172                         goto bail;
1173                 if (qp->s_rnr_retry == 0) {
1174                         status = IB_WC_RNR_RETRY_EXC_ERR;
1175                         goto class_b;
1176                 }
1177                 if (qp->s_rnr_retry_cnt < 7)
1178                         qp->s_rnr_retry--;
1179
1180                 /* The last valid PSN is the previous PSN. */
1181                 update_last_psn(qp, psn - 1);
1182
1183                 ibp->rvp.n_rc_resends += (qp->s_psn - psn) & QIB_PSN_MASK;
1184
1185                 reset_psn(qp, psn);
1186
1187                 qp->s_flags &= ~(RVT_S_WAIT_SSN_CREDIT | RVT_S_WAIT_ACK);
1188                 rvt_stop_rc_timers(qp);
1189                 rvt_add_rnr_timer(qp, aeth);
1190                 return 0;
1191
1192         case 3:         /* NAK */
1193                 if (qp->s_acked == qp->s_tail)
1194                         goto bail;
1195                 /* The last valid PSN is the previous PSN. */
1196                 update_last_psn(qp, psn - 1);
1197                 switch ((aeth >> IB_AETH_CREDIT_SHIFT) &
1198                         IB_AETH_CREDIT_MASK) {
1199                 case 0: /* PSN sequence error */
1200                         ibp->rvp.n_seq_naks++;
1201                         /*
1202                          * Back up to the responder's expected PSN.
1203                          * Note that we might get a NAK in the middle of an
1204                          * RDMA READ response which terminates the RDMA
1205                          * READ.
1206                          */
1207                         qib_restart_rc(qp, psn, 0);
1208                         qib_schedule_send(qp);
1209                         break;
1210
1211                 case 1: /* Invalid Request */
1212                         status = IB_WC_REM_INV_REQ_ERR;
1213                         ibp->rvp.n_other_naks++;
1214                         goto class_b;
1215
1216                 case 2: /* Remote Access Error */
1217                         status = IB_WC_REM_ACCESS_ERR;
1218                         ibp->rvp.n_other_naks++;
1219                         goto class_b;
1220
1221                 case 3: /* Remote Operation Error */
1222                         status = IB_WC_REM_OP_ERR;
1223                         ibp->rvp.n_other_naks++;
1224 class_b:
1225                         if (qp->s_last == qp->s_acked) {
1226                                 qib_send_complete(qp, wqe, status);
1227                                 rvt_error_qp(qp, IB_WC_WR_FLUSH_ERR);
1228                         }
1229                         break;
1230
1231                 default:
1232                         /* Ignore other reserved NAK error codes */
1233                         goto reserved;
1234                 }
1235                 qp->s_retry = qp->s_retry_cnt;
1236                 qp->s_rnr_retry = qp->s_rnr_retry_cnt;
1237                 goto bail;
1238
1239         default:                /* 2: reserved */
1240 reserved:
1241                 /* Ignore reserved NAK codes. */
1242                 goto bail;
1243         }
1244
1245 bail:
1246         rvt_stop_rc_timers(qp);
1247         return ret;
1248 }
1249
1250 /*
1251  * We have seen an out of sequence RDMA read middle or last packet.
1252  * This ACKs SENDs and RDMA writes up to the first RDMA read or atomic SWQE.
1253  */
1254 static void rdma_seq_err(struct rvt_qp *qp, struct qib_ibport *ibp, u32 psn,
1255                          struct qib_ctxtdata *rcd)
1256 {
1257         struct rvt_swqe *wqe;
1258
1259         /* Remove QP from retry timer */
1260         rvt_stop_rc_timers(qp);
1261
1262         wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1263
1264         while (qib_cmp24(psn, wqe->lpsn) > 0) {
1265                 if (wqe->wr.opcode == IB_WR_RDMA_READ ||
1266                     wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1267                     wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)
1268                         break;
1269                 wqe = do_rc_completion(qp, wqe, ibp);
1270         }
1271
1272         ibp->rvp.n_rdma_seq++;
1273         qp->r_flags |= RVT_R_RDMAR_SEQ;
1274         qib_restart_rc(qp, qp->s_last_psn + 1, 0);
1275         if (list_empty(&qp->rspwait)) {
1276                 qp->r_flags |= RVT_R_RSP_SEND;
1277                 rvt_get_qp(qp);
1278                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
1279         }
1280 }
1281
1282 /**
1283  * qib_rc_rcv_resp - process an incoming RC response packet
1284  * @ibp: the port this packet came in on
1285  * @ohdr: the other headers for this packet
1286  * @data: the packet data
1287  * @tlen: the packet length
1288  * @qp: the QP for this packet
1289  * @opcode: the opcode for this packet
1290  * @psn: the packet sequence number for this packet
1291  * @hdrsize: the header length
1292  * @pmtu: the path MTU
1293  *
1294  * This is called from qib_rc_rcv() to process an incoming RC response
1295  * packet for the given QP.
1296  * Called at interrupt level.
1297  */
1298 static void qib_rc_rcv_resp(struct qib_ibport *ibp,
1299                             struct ib_other_headers *ohdr,
1300                             void *data, u32 tlen,
1301                             struct rvt_qp *qp,
1302                             u32 opcode,
1303                             u32 psn, u32 hdrsize, u32 pmtu,
1304                             struct qib_ctxtdata *rcd)
1305 {
1306         struct rvt_swqe *wqe;
1307         struct qib_pportdata *ppd = ppd_from_ibp(ibp);
1308         enum ib_wc_status status;
1309         unsigned long flags;
1310         int diff;
1311         u32 pad;
1312         u32 aeth;
1313         u64 val;
1314
1315         if (opcode != OP(RDMA_READ_RESPONSE_MIDDLE)) {
1316                 /*
1317                  * If ACK'd PSN on SDMA busy list try to make progress to
1318                  * reclaim SDMA credits.
1319                  */
1320                 if ((qib_cmp24(psn, qp->s_sending_psn) >= 0) &&
1321                     (qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) <= 0)) {
1322
1323                         /*
1324                          * If send tasklet not running attempt to progress
1325                          * SDMA queue.
1326                          */
1327                         if (!(qp->s_flags & RVT_S_BUSY)) {
1328                                 /* Acquire SDMA Lock */
1329                                 spin_lock_irqsave(&ppd->sdma_lock, flags);
1330                                 /* Invoke sdma make progress */
1331                                 qib_sdma_make_progress(ppd);
1332                                 /* Release SDMA Lock */
1333                                 spin_unlock_irqrestore(&ppd->sdma_lock, flags);
1334                         }
1335                 }
1336         }
1337
1338         spin_lock_irqsave(&qp->s_lock, flags);
1339         if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK))
1340                 goto ack_done;
1341
1342         /* Ignore invalid responses. */
1343         smp_read_barrier_depends(); /* see post_one_send */
1344         if (qib_cmp24(psn, READ_ONCE(qp->s_next_psn)) >= 0)
1345                 goto ack_done;
1346
1347         /* Ignore duplicate responses. */
1348         diff = qib_cmp24(psn, qp->s_last_psn);
1349         if (unlikely(diff <= 0)) {
1350                 /* Update credits for "ghost" ACKs */
1351                 if (diff == 0 && opcode == OP(ACKNOWLEDGE)) {
1352                         aeth = be32_to_cpu(ohdr->u.aeth);
1353                         if ((aeth >> IB_AETH_NAK_SHIFT) == 0)
1354                                 rvt_get_credit(qp, aeth);
1355                 }
1356                 goto ack_done;
1357         }
1358
1359         /*
1360          * Skip everything other than the PSN we expect, if we are waiting
1361          * for a reply to a restarted RDMA read or atomic op.
1362          */
1363         if (qp->r_flags & RVT_R_RDMAR_SEQ) {
1364                 if (qib_cmp24(psn, qp->s_last_psn + 1) != 0)
1365                         goto ack_done;
1366                 qp->r_flags &= ~RVT_R_RDMAR_SEQ;
1367         }
1368
1369         if (unlikely(qp->s_acked == qp->s_tail))
1370                 goto ack_done;
1371         wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1372         status = IB_WC_SUCCESS;
1373
1374         switch (opcode) {
1375         case OP(ACKNOWLEDGE):
1376         case OP(ATOMIC_ACKNOWLEDGE):
1377         case OP(RDMA_READ_RESPONSE_FIRST):
1378                 aeth = be32_to_cpu(ohdr->u.aeth);
1379                 if (opcode == OP(ATOMIC_ACKNOWLEDGE))
1380                         val = ib_u64_get(&ohdr->u.at.atomic_ack_eth);
1381                 else
1382                         val = 0;
1383                 if (!do_rc_ack(qp, aeth, psn, opcode, val, rcd) ||
1384                     opcode != OP(RDMA_READ_RESPONSE_FIRST))
1385                         goto ack_done;
1386                 hdrsize += 4;
1387                 wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1388                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1389                         goto ack_op_err;
1390                 /*
1391                  * If this is a response to a resent RDMA read, we
1392                  * have to be careful to copy the data to the right
1393                  * location.
1394                  */
1395                 qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
1396                                                   wqe, psn, pmtu);
1397                 goto read_middle;
1398
1399         case OP(RDMA_READ_RESPONSE_MIDDLE):
1400                 /* no AETH, no ACK */
1401                 if (unlikely(qib_cmp24(psn, qp->s_last_psn + 1)))
1402                         goto ack_seq_err;
1403                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1404                         goto ack_op_err;
1405 read_middle:
1406                 if (unlikely(tlen != (hdrsize + pmtu + 4)))
1407                         goto ack_len_err;
1408                 if (unlikely(pmtu >= qp->s_rdma_read_len))
1409                         goto ack_len_err;
1410
1411                 /*
1412                  * We got a response so update the timeout.
1413                  * 4.096 usec. * (1 << qp->timeout)
1414                  */
1415                 rvt_mod_retry_timer(qp);
1416                 if (qp->s_flags & RVT_S_WAIT_ACK) {
1417                         qp->s_flags &= ~RVT_S_WAIT_ACK;
1418                         qib_schedule_send(qp);
1419                 }
1420
1421                 if (opcode == OP(RDMA_READ_RESPONSE_MIDDLE))
1422                         qp->s_retry = qp->s_retry_cnt;
1423
1424                 /*
1425                  * Update the RDMA receive state but do the copy w/o
1426                  * holding the locks and blocking interrupts.
1427                  */
1428                 qp->s_rdma_read_len -= pmtu;
1429                 update_last_psn(qp, psn);
1430                 spin_unlock_irqrestore(&qp->s_lock, flags);
1431                 qib_copy_sge(&qp->s_rdma_read_sge, data, pmtu, 0);
1432                 goto bail;
1433
1434         case OP(RDMA_READ_RESPONSE_ONLY):
1435                 aeth = be32_to_cpu(ohdr->u.aeth);
1436                 if (!do_rc_ack(qp, aeth, psn, opcode, 0, rcd))
1437                         goto ack_done;
1438                 /* Get the number of bytes the message was padded by. */
1439                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1440                 /*
1441                  * Check that the data size is >= 0 && <= pmtu.
1442                  * Remember to account for the AETH header (4) and
1443                  * ICRC (4).
1444                  */
1445                 if (unlikely(tlen < (hdrsize + pad + 8)))
1446                         goto ack_len_err;
1447                 /*
1448                  * If this is a response to a resent RDMA read, we
1449                  * have to be careful to copy the data to the right
1450                  * location.
1451                  */
1452                 wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1453                 qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
1454                                                   wqe, psn, pmtu);
1455                 goto read_last;
1456
1457         case OP(RDMA_READ_RESPONSE_LAST):
1458                 /* ACKs READ req. */
1459                 if (unlikely(qib_cmp24(psn, qp->s_last_psn + 1)))
1460                         goto ack_seq_err;
1461                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1462                         goto ack_op_err;
1463                 /* Get the number of bytes the message was padded by. */
1464                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1465                 /*
1466                  * Check that the data size is >= 1 && <= pmtu.
1467                  * Remember to account for the AETH header (4) and
1468                  * ICRC (4).
1469                  */
1470                 if (unlikely(tlen <= (hdrsize + pad + 8)))
1471                         goto ack_len_err;
1472 read_last:
1473                 tlen -= hdrsize + pad + 8;
1474                 if (unlikely(tlen != qp->s_rdma_read_len))
1475                         goto ack_len_err;
1476                 aeth = be32_to_cpu(ohdr->u.aeth);
1477                 qib_copy_sge(&qp->s_rdma_read_sge, data, tlen, 0);
1478                 WARN_ON(qp->s_rdma_read_sge.num_sge);
1479                 (void) do_rc_ack(qp, aeth, psn,
1480                                  OP(RDMA_READ_RESPONSE_LAST), 0, rcd);
1481                 goto ack_done;
1482         }
1483
1484 ack_op_err:
1485         status = IB_WC_LOC_QP_OP_ERR;
1486         goto ack_err;
1487
1488 ack_seq_err:
1489         rdma_seq_err(qp, ibp, psn, rcd);
1490         goto ack_done;
1491
1492 ack_len_err:
1493         status = IB_WC_LOC_LEN_ERR;
1494 ack_err:
1495         if (qp->s_last == qp->s_acked) {
1496                 qib_send_complete(qp, wqe, status);
1497                 rvt_error_qp(qp, IB_WC_WR_FLUSH_ERR);
1498         }
1499 ack_done:
1500         spin_unlock_irqrestore(&qp->s_lock, flags);
1501 bail:
1502         return;
1503 }
1504
1505 /**
1506  * qib_rc_rcv_error - process an incoming duplicate or error RC packet
1507  * @ohdr: the other headers for this packet
1508  * @data: the packet data
1509  * @qp: the QP for this packet
1510  * @opcode: the opcode for this packet
1511  * @psn: the packet sequence number for this packet
1512  * @diff: the difference between the PSN and the expected PSN
1513  *
1514  * This is called from qib_rc_rcv() to process an unexpected
1515  * incoming RC packet for the given QP.
1516  * Called at interrupt level.
1517  * Return 1 if no more processing is needed; otherwise return 0 to
1518  * schedule a response to be sent.
1519  */
1520 static int qib_rc_rcv_error(struct ib_other_headers *ohdr,
1521                             void *data,
1522                             struct rvt_qp *qp,
1523                             u32 opcode,
1524                             u32 psn,
1525                             int diff,
1526                             struct qib_ctxtdata *rcd)
1527 {
1528         struct qib_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
1529         struct rvt_ack_entry *e;
1530         unsigned long flags;
1531         u8 i, prev;
1532         int old_req;
1533
1534         if (diff > 0) {
1535                 /*
1536                  * Packet sequence error.
1537                  * A NAK will ACK earlier sends and RDMA writes.
1538                  * Don't queue the NAK if we already sent one.
1539                  */
1540                 if (!qp->r_nak_state) {
1541                         ibp->rvp.n_rc_seqnak++;
1542                         qp->r_nak_state = IB_NAK_PSN_ERROR;
1543                         /* Use the expected PSN. */
1544                         qp->r_ack_psn = qp->r_psn;
1545                         /*
1546                          * Wait to send the sequence NAK until all packets
1547                          * in the receive queue have been processed.
1548                          * Otherwise, we end up propagating congestion.
1549                          */
1550                         if (list_empty(&qp->rspwait)) {
1551                                 qp->r_flags |= RVT_R_RSP_NAK;
1552                                 rvt_get_qp(qp);
1553                                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
1554                         }
1555                 }
1556                 goto done;
1557         }
1558
1559         /*
1560          * Handle a duplicate request.  Don't re-execute SEND, RDMA
1561          * write or atomic op.  Don't NAK errors, just silently drop
1562          * the duplicate request.  Note that r_sge, r_len, and
1563          * r_rcv_len may be in use so don't modify them.
1564          *
1565          * We are supposed to ACK the earliest duplicate PSN but we
1566          * can coalesce an outstanding duplicate ACK.  We have to
1567          * send the earliest so that RDMA reads can be restarted at
1568          * the requester's expected PSN.
1569          *
1570          * First, find where this duplicate PSN falls within the
1571          * ACKs previously sent.
1572          * old_req is true if there is an older response that is scheduled
1573          * to be sent before sending this one.
1574          */
1575         e = NULL;
1576         old_req = 1;
1577         ibp->rvp.n_rc_dupreq++;
1578
1579         spin_lock_irqsave(&qp->s_lock, flags);
1580
1581         for (i = qp->r_head_ack_queue; ; i = prev) {
1582                 if (i == qp->s_tail_ack_queue)
1583                         old_req = 0;
1584                 if (i)
1585                         prev = i - 1;
1586                 else
1587                         prev = QIB_MAX_RDMA_ATOMIC;
1588                 if (prev == qp->r_head_ack_queue) {
1589                         e = NULL;
1590                         break;
1591                 }
1592                 e = &qp->s_ack_queue[prev];
1593                 if (!e->opcode) {
1594                         e = NULL;
1595                         break;
1596                 }
1597                 if (qib_cmp24(psn, e->psn) >= 0) {
1598                         if (prev == qp->s_tail_ack_queue &&
1599                             qib_cmp24(psn, e->lpsn) <= 0)
1600                                 old_req = 0;
1601                         break;
1602                 }
1603         }
1604         switch (opcode) {
1605         case OP(RDMA_READ_REQUEST): {
1606                 struct ib_reth *reth;
1607                 u32 offset;
1608                 u32 len;
1609
1610                 /*
1611                  * If we didn't find the RDMA read request in the ack queue,
1612                  * we can ignore this request.
1613                  */
1614                 if (!e || e->opcode != OP(RDMA_READ_REQUEST))
1615                         goto unlock_done;
1616                 /* RETH comes after BTH */
1617                 reth = &ohdr->u.rc.reth;
1618                 /*
1619                  * Address range must be a subset of the original
1620                  * request and start on pmtu boundaries.
1621                  * We reuse the old ack_queue slot since the requester
1622                  * should not back up and request an earlier PSN for the
1623                  * same request.
1624                  */
1625                 offset = ((psn - e->psn) & QIB_PSN_MASK) *
1626                         qp->pmtu;
1627                 len = be32_to_cpu(reth->length);
1628                 if (unlikely(offset + len != e->rdma_sge.sge_length))
1629                         goto unlock_done;
1630                 if (e->rdma_sge.mr) {
1631                         rvt_put_mr(e->rdma_sge.mr);
1632                         e->rdma_sge.mr = NULL;
1633                 }
1634                 if (len != 0) {
1635                         u32 rkey = be32_to_cpu(reth->rkey);
1636                         u64 vaddr = be64_to_cpu(reth->vaddr);
1637                         int ok;
1638
1639                         ok = rvt_rkey_ok(qp, &e->rdma_sge, len, vaddr, rkey,
1640                                          IB_ACCESS_REMOTE_READ);
1641                         if (unlikely(!ok))
1642                                 goto unlock_done;
1643                 } else {
1644                         e->rdma_sge.vaddr = NULL;
1645                         e->rdma_sge.length = 0;
1646                         e->rdma_sge.sge_length = 0;
1647                 }
1648                 e->psn = psn;
1649                 if (old_req)
1650                         goto unlock_done;
1651                 qp->s_tail_ack_queue = prev;
1652                 break;
1653         }
1654
1655         case OP(COMPARE_SWAP):
1656         case OP(FETCH_ADD): {
1657                 /*
1658                  * If we didn't find the atomic request in the ack queue
1659                  * or the send tasklet is already backed up to send an
1660                  * earlier entry, we can ignore this request.
1661                  */
1662                 if (!e || e->opcode != (u8) opcode || old_req)
1663                         goto unlock_done;
1664                 qp->s_tail_ack_queue = prev;
1665                 break;
1666         }
1667
1668         default:
1669                 /*
1670                  * Ignore this operation if it doesn't request an ACK
1671                  * or an earlier RDMA read or atomic is going to be resent.
1672                  */
1673                 if (!(psn & IB_BTH_REQ_ACK) || old_req)
1674                         goto unlock_done;
1675                 /*
1676                  * Resend the most recent ACK if this request is
1677                  * after all the previous RDMA reads and atomics.
1678                  */
1679                 if (i == qp->r_head_ack_queue) {
1680                         spin_unlock_irqrestore(&qp->s_lock, flags);
1681                         qp->r_nak_state = 0;
1682                         qp->r_ack_psn = qp->r_psn - 1;
1683                         goto send_ack;
1684                 }
1685                 /*
1686                  * Try to send a simple ACK to work around a Mellanox bug
1687                  * which doesn't accept a RDMA read response or atomic
1688                  * response as an ACK for earlier SENDs or RDMA writes.
1689                  */
1690                 if (!(qp->s_flags & RVT_S_RESP_PENDING)) {
1691                         spin_unlock_irqrestore(&qp->s_lock, flags);
1692                         qp->r_nak_state = 0;
1693                         qp->r_ack_psn = qp->s_ack_queue[i].psn - 1;
1694                         goto send_ack;
1695                 }
1696                 /*
1697                  * Resend the RDMA read or atomic op which
1698                  * ACKs this duplicate request.
1699                  */
1700                 qp->s_tail_ack_queue = i;
1701                 break;
1702         }
1703         qp->s_ack_state = OP(ACKNOWLEDGE);
1704         qp->s_flags |= RVT_S_RESP_PENDING;
1705         qp->r_nak_state = 0;
1706         qib_schedule_send(qp);
1707
1708 unlock_done:
1709         spin_unlock_irqrestore(&qp->s_lock, flags);
1710 done:
1711         return 1;
1712
1713 send_ack:
1714         return 0;
1715 }
1716
1717 static inline void qib_update_ack_queue(struct rvt_qp *qp, unsigned n)
1718 {
1719         unsigned next;
1720
1721         next = n + 1;
1722         if (next > QIB_MAX_RDMA_ATOMIC)
1723                 next = 0;
1724         qp->s_tail_ack_queue = next;
1725         qp->s_ack_state = OP(ACKNOWLEDGE);
1726 }
1727
1728 /**
1729  * qib_rc_rcv - process an incoming RC packet
1730  * @rcd: the context pointer
1731  * @hdr: the header of this packet
1732  * @has_grh: true if the header has a GRH
1733  * @data: the packet data
1734  * @tlen: the packet length
1735  * @qp: the QP for this packet
1736  *
1737  * This is called from qib_qp_rcv() to process an incoming RC packet
1738  * for the given QP.
1739  * Called at interrupt level.
1740  */
1741 void qib_rc_rcv(struct qib_ctxtdata *rcd, struct ib_header *hdr,
1742                 int has_grh, void *data, u32 tlen, struct rvt_qp *qp)
1743 {
1744         struct qib_ibport *ibp = &rcd->ppd->ibport_data;
1745         struct ib_other_headers *ohdr;
1746         u32 opcode;
1747         u32 hdrsize;
1748         u32 psn;
1749         u32 pad;
1750         struct ib_wc wc;
1751         u32 pmtu = qp->pmtu;
1752         int diff;
1753         struct ib_reth *reth;
1754         unsigned long flags;
1755         int ret;
1756
1757         /* Check for GRH */
1758         if (!has_grh) {
1759                 ohdr = &hdr->u.oth;
1760                 hdrsize = 8 + 12;       /* LRH + BTH */
1761         } else {
1762                 ohdr = &hdr->u.l.oth;
1763                 hdrsize = 8 + 40 + 12;  /* LRH + GRH + BTH */
1764         }
1765
1766         opcode = be32_to_cpu(ohdr->bth[0]);
1767         if (qib_ruc_check_hdr(ibp, hdr, has_grh, qp, opcode))
1768                 return;
1769
1770         psn = be32_to_cpu(ohdr->bth[2]);
1771         opcode >>= 24;
1772
1773         /*
1774          * Process responses (ACKs) before anything else.  Note that the
1775          * packet sequence number will be for something in the send work
1776          * queue rather than the expected receive packet sequence number.
1777          * In other words, this QP is the requester.
1778          */
1779         if (opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
1780             opcode <= OP(ATOMIC_ACKNOWLEDGE)) {
1781                 qib_rc_rcv_resp(ibp, ohdr, data, tlen, qp, opcode, psn,
1782                                 hdrsize, pmtu, rcd);
1783                 return;
1784         }
1785
1786         /* Compute 24 bits worth of difference. */
1787         diff = qib_cmp24(psn, qp->r_psn);
1788         if (unlikely(diff)) {
1789                 if (qib_rc_rcv_error(ohdr, data, qp, opcode, psn, diff, rcd))
1790                         return;
1791                 goto send_ack;
1792         }
1793
1794         /* Check for opcode sequence errors. */
1795         switch (qp->r_state) {
1796         case OP(SEND_FIRST):
1797         case OP(SEND_MIDDLE):
1798                 if (opcode == OP(SEND_MIDDLE) ||
1799                     opcode == OP(SEND_LAST) ||
1800                     opcode == OP(SEND_LAST_WITH_IMMEDIATE))
1801                         break;
1802                 goto nack_inv;
1803
1804         case OP(RDMA_WRITE_FIRST):
1805         case OP(RDMA_WRITE_MIDDLE):
1806                 if (opcode == OP(RDMA_WRITE_MIDDLE) ||
1807                     opcode == OP(RDMA_WRITE_LAST) ||
1808                     opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
1809                         break;
1810                 goto nack_inv;
1811
1812         default:
1813                 if (opcode == OP(SEND_MIDDLE) ||
1814                     opcode == OP(SEND_LAST) ||
1815                     opcode == OP(SEND_LAST_WITH_IMMEDIATE) ||
1816                     opcode == OP(RDMA_WRITE_MIDDLE) ||
1817                     opcode == OP(RDMA_WRITE_LAST) ||
1818                     opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
1819                         goto nack_inv;
1820                 /*
1821                  * Note that it is up to the requester to not send a new
1822                  * RDMA read or atomic operation before receiving an ACK
1823                  * for the previous operation.
1824                  */
1825                 break;
1826         }
1827
1828         if (qp->state == IB_QPS_RTR && !(qp->r_flags & RVT_R_COMM_EST))
1829                 rvt_comm_est(qp);
1830
1831         /* OK, process the packet. */
1832         switch (opcode) {
1833         case OP(SEND_FIRST):
1834                 ret = qib_get_rwqe(qp, 0);
1835                 if (ret < 0)
1836                         goto nack_op_err;
1837                 if (!ret)
1838                         goto rnr_nak;
1839                 qp->r_rcv_len = 0;
1840                 /* FALLTHROUGH */
1841         case OP(SEND_MIDDLE):
1842         case OP(RDMA_WRITE_MIDDLE):
1843 send_middle:
1844                 /* Check for invalid length PMTU or posted rwqe len. */
1845                 if (unlikely(tlen != (hdrsize + pmtu + 4)))
1846                         goto nack_inv;
1847                 qp->r_rcv_len += pmtu;
1848                 if (unlikely(qp->r_rcv_len > qp->r_len))
1849                         goto nack_inv;
1850                 qib_copy_sge(&qp->r_sge, data, pmtu, 1);
1851                 break;
1852
1853         case OP(RDMA_WRITE_LAST_WITH_IMMEDIATE):
1854                 /* consume RWQE */
1855                 ret = qib_get_rwqe(qp, 1);
1856                 if (ret < 0)
1857                         goto nack_op_err;
1858                 if (!ret)
1859                         goto rnr_nak;
1860                 goto send_last_imm;
1861
1862         case OP(SEND_ONLY):
1863         case OP(SEND_ONLY_WITH_IMMEDIATE):
1864                 ret = qib_get_rwqe(qp, 0);
1865                 if (ret < 0)
1866                         goto nack_op_err;
1867                 if (!ret)
1868                         goto rnr_nak;
1869                 qp->r_rcv_len = 0;
1870                 if (opcode == OP(SEND_ONLY))
1871                         goto no_immediate_data;
1872                 /* FALLTHROUGH for SEND_ONLY_WITH_IMMEDIATE */
1873         case OP(SEND_LAST_WITH_IMMEDIATE):
1874 send_last_imm:
1875                 wc.ex.imm_data = ohdr->u.imm_data;
1876                 hdrsize += 4;
1877                 wc.wc_flags = IB_WC_WITH_IMM;
1878                 goto send_last;
1879         case OP(SEND_LAST):
1880         case OP(RDMA_WRITE_LAST):
1881 no_immediate_data:
1882                 wc.wc_flags = 0;
1883                 wc.ex.imm_data = 0;
1884 send_last:
1885                 /* Get the number of bytes the message was padded by. */
1886                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1887                 /* Check for invalid length. */
1888                 /* XXX LAST len should be >= 1 */
1889                 if (unlikely(tlen < (hdrsize + pad + 4)))
1890                         goto nack_inv;
1891                 /* Don't count the CRC. */
1892                 tlen -= (hdrsize + pad + 4);
1893                 wc.byte_len = tlen + qp->r_rcv_len;
1894                 if (unlikely(wc.byte_len > qp->r_len))
1895                         goto nack_inv;
1896                 qib_copy_sge(&qp->r_sge, data, tlen, 1);
1897                 rvt_put_ss(&qp->r_sge);
1898                 qp->r_msn++;
1899                 if (!test_and_clear_bit(RVT_R_WRID_VALID, &qp->r_aflags))
1900                         break;
1901                 wc.wr_id = qp->r_wr_id;
1902                 wc.status = IB_WC_SUCCESS;
1903                 if (opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE) ||
1904                     opcode == OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE))
1905                         wc.opcode = IB_WC_RECV_RDMA_WITH_IMM;
1906                 else
1907                         wc.opcode = IB_WC_RECV;
1908                 wc.qp = &qp->ibqp;
1909                 wc.src_qp = qp->remote_qpn;
1910                 wc.slid = rdma_ah_get_dlid(&qp->remote_ah_attr);
1911                 wc.sl = rdma_ah_get_sl(&qp->remote_ah_attr);
1912                 /* zero fields that are N/A */
1913                 wc.vendor_err = 0;
1914                 wc.pkey_index = 0;
1915                 wc.dlid_path_bits = 0;
1916                 wc.port_num = 0;
1917                 /* Signal completion event if the solicited bit is set. */
1918                 rvt_cq_enter(ibcq_to_rvtcq(qp->ibqp.recv_cq), &wc,
1919                              (ohdr->bth[0] &
1920                               cpu_to_be32(IB_BTH_SOLICITED)) != 0);
1921                 break;
1922
1923         case OP(RDMA_WRITE_FIRST):
1924         case OP(RDMA_WRITE_ONLY):
1925         case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE):
1926                 if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_WRITE)))
1927                         goto nack_inv;
1928                 /* consume RWQE */
1929                 reth = &ohdr->u.rc.reth;
1930                 hdrsize += sizeof(*reth);
1931                 qp->r_len = be32_to_cpu(reth->length);
1932                 qp->r_rcv_len = 0;
1933                 qp->r_sge.sg_list = NULL;
1934                 if (qp->r_len != 0) {
1935                         u32 rkey = be32_to_cpu(reth->rkey);
1936                         u64 vaddr = be64_to_cpu(reth->vaddr);
1937                         int ok;
1938
1939                         /* Check rkey & NAK */
1940                         ok = rvt_rkey_ok(qp, &qp->r_sge.sge, qp->r_len, vaddr,
1941                                          rkey, IB_ACCESS_REMOTE_WRITE);
1942                         if (unlikely(!ok))
1943                                 goto nack_acc;
1944                         qp->r_sge.num_sge = 1;
1945                 } else {
1946                         qp->r_sge.num_sge = 0;
1947                         qp->r_sge.sge.mr = NULL;
1948                         qp->r_sge.sge.vaddr = NULL;
1949                         qp->r_sge.sge.length = 0;
1950                         qp->r_sge.sge.sge_length = 0;
1951                 }
1952                 if (opcode == OP(RDMA_WRITE_FIRST))
1953                         goto send_middle;
1954                 else if (opcode == OP(RDMA_WRITE_ONLY))
1955                         goto no_immediate_data;
1956                 ret = qib_get_rwqe(qp, 1);
1957                 if (ret < 0)
1958                         goto nack_op_err;
1959                 if (!ret) {
1960                         rvt_put_ss(&qp->r_sge);
1961                         goto rnr_nak;
1962                 }
1963                 wc.ex.imm_data = ohdr->u.rc.imm_data;
1964                 hdrsize += 4;
1965                 wc.wc_flags = IB_WC_WITH_IMM;
1966                 goto send_last;
1967
1968         case OP(RDMA_READ_REQUEST): {
1969                 struct rvt_ack_entry *e;
1970                 u32 len;
1971                 u8 next;
1972
1973                 if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_READ)))
1974                         goto nack_inv;
1975                 next = qp->r_head_ack_queue + 1;
1976                 /* s_ack_queue is size QIB_MAX_RDMA_ATOMIC+1 so use > not >= */
1977                 if (next > QIB_MAX_RDMA_ATOMIC)
1978                         next = 0;
1979                 spin_lock_irqsave(&qp->s_lock, flags);
1980                 if (unlikely(next == qp->s_tail_ack_queue)) {
1981                         if (!qp->s_ack_queue[next].sent)
1982                                 goto nack_inv_unlck;
1983                         qib_update_ack_queue(qp, next);
1984                 }
1985                 e = &qp->s_ack_queue[qp->r_head_ack_queue];
1986                 if (e->opcode == OP(RDMA_READ_REQUEST) && e->rdma_sge.mr) {
1987                         rvt_put_mr(e->rdma_sge.mr);
1988                         e->rdma_sge.mr = NULL;
1989                 }
1990                 reth = &ohdr->u.rc.reth;
1991                 len = be32_to_cpu(reth->length);
1992                 if (len) {
1993                         u32 rkey = be32_to_cpu(reth->rkey);
1994                         u64 vaddr = be64_to_cpu(reth->vaddr);
1995                         int ok;
1996
1997                         /* Check rkey & NAK */
1998                         ok = rvt_rkey_ok(qp, &e->rdma_sge, len, vaddr,
1999                                          rkey, IB_ACCESS_REMOTE_READ);
2000                         if (unlikely(!ok))
2001                                 goto nack_acc_unlck;
2002                         /*
2003                          * Update the next expected PSN.  We add 1 later
2004                          * below, so only add the remainder here.
2005                          */
2006                         qp->r_psn += rvt_div_mtu(qp, len - 1);
2007                 } else {
2008                         e->rdma_sge.mr = NULL;
2009                         e->rdma_sge.vaddr = NULL;
2010                         e->rdma_sge.length = 0;
2011                         e->rdma_sge.sge_length = 0;
2012                 }
2013                 e->opcode = opcode;
2014                 e->sent = 0;
2015                 e->psn = psn;
2016                 e->lpsn = qp->r_psn;
2017                 /*
2018                  * We need to increment the MSN here instead of when we
2019                  * finish sending the result since a duplicate request would
2020                  * increment it more than once.
2021                  */
2022                 qp->r_msn++;
2023                 qp->r_psn++;
2024                 qp->r_state = opcode;
2025                 qp->r_nak_state = 0;
2026                 qp->r_head_ack_queue = next;
2027
2028                 /* Schedule the send tasklet. */
2029                 qp->s_flags |= RVT_S_RESP_PENDING;
2030                 qib_schedule_send(qp);
2031
2032                 goto sunlock;
2033         }
2034
2035         case OP(COMPARE_SWAP):
2036         case OP(FETCH_ADD): {
2037                 struct ib_atomic_eth *ateth;
2038                 struct rvt_ack_entry *e;
2039                 u64 vaddr;
2040                 atomic64_t *maddr;
2041                 u64 sdata;
2042                 u32 rkey;
2043                 u8 next;
2044
2045                 if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_ATOMIC)))
2046                         goto nack_inv;
2047                 next = qp->r_head_ack_queue + 1;
2048                 if (next > QIB_MAX_RDMA_ATOMIC)
2049                         next = 0;
2050                 spin_lock_irqsave(&qp->s_lock, flags);
2051                 if (unlikely(next == qp->s_tail_ack_queue)) {
2052                         if (!qp->s_ack_queue[next].sent)
2053                                 goto nack_inv_unlck;
2054                         qib_update_ack_queue(qp, next);
2055                 }
2056                 e = &qp->s_ack_queue[qp->r_head_ack_queue];
2057                 if (e->opcode == OP(RDMA_READ_REQUEST) && e->rdma_sge.mr) {
2058                         rvt_put_mr(e->rdma_sge.mr);
2059                         e->rdma_sge.mr = NULL;
2060                 }
2061                 ateth = &ohdr->u.atomic_eth;
2062                 vaddr = get_ib_ateth_vaddr(ateth);
2063                 if (unlikely(vaddr & (sizeof(u64) - 1)))
2064                         goto nack_inv_unlck;
2065                 rkey = be32_to_cpu(ateth->rkey);
2066                 /* Check rkey & NAK */
2067                 if (unlikely(!rvt_rkey_ok(qp, &qp->r_sge.sge, sizeof(u64),
2068                                           vaddr, rkey,
2069                                           IB_ACCESS_REMOTE_ATOMIC)))
2070                         goto nack_acc_unlck;
2071                 /* Perform atomic OP and save result. */
2072                 maddr = (atomic64_t *) qp->r_sge.sge.vaddr;
2073                 sdata = get_ib_ateth_swap(ateth);
2074                 e->atomic_data = (opcode == OP(FETCH_ADD)) ?
2075                         (u64) atomic64_add_return(sdata, maddr) - sdata :
2076                         (u64) cmpxchg((u64 *) qp->r_sge.sge.vaddr,
2077                                       get_ib_ateth_compare(ateth),
2078                                       sdata);
2079                 rvt_put_mr(qp->r_sge.sge.mr);
2080                 qp->r_sge.num_sge = 0;
2081                 e->opcode = opcode;
2082                 e->sent = 0;
2083                 e->psn = psn;
2084                 e->lpsn = psn;
2085                 qp->r_msn++;
2086                 qp->r_psn++;
2087                 qp->r_state = opcode;
2088                 qp->r_nak_state = 0;
2089                 qp->r_head_ack_queue = next;
2090
2091                 /* Schedule the send tasklet. */
2092                 qp->s_flags |= RVT_S_RESP_PENDING;
2093                 qib_schedule_send(qp);
2094
2095                 goto sunlock;
2096         }
2097
2098         default:
2099                 /* NAK unknown opcodes. */
2100                 goto nack_inv;
2101         }
2102         qp->r_psn++;
2103         qp->r_state = opcode;
2104         qp->r_ack_psn = psn;
2105         qp->r_nak_state = 0;
2106         /* Send an ACK if requested or required. */
2107         if (psn & (1 << 31))
2108                 goto send_ack;
2109         return;
2110
2111 rnr_nak:
2112         qp->r_nak_state = IB_RNR_NAK | qp->r_min_rnr_timer;
2113         qp->r_ack_psn = qp->r_psn;
2114         /* Queue RNR NAK for later */
2115         if (list_empty(&qp->rspwait)) {
2116                 qp->r_flags |= RVT_R_RSP_NAK;
2117                 rvt_get_qp(qp);
2118                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
2119         }
2120         return;
2121
2122 nack_op_err:
2123         rvt_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
2124         qp->r_nak_state = IB_NAK_REMOTE_OPERATIONAL_ERROR;
2125         qp->r_ack_psn = qp->r_psn;
2126         /* Queue NAK for later */
2127         if (list_empty(&qp->rspwait)) {
2128                 qp->r_flags |= RVT_R_RSP_NAK;
2129                 rvt_get_qp(qp);
2130                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
2131         }
2132         return;
2133
2134 nack_inv_unlck:
2135         spin_unlock_irqrestore(&qp->s_lock, flags);
2136 nack_inv:
2137         rvt_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
2138         qp->r_nak_state = IB_NAK_INVALID_REQUEST;
2139         qp->r_ack_psn = qp->r_psn;
2140         /* Queue NAK for later */
2141         if (list_empty(&qp->rspwait)) {
2142                 qp->r_flags |= RVT_R_RSP_NAK;
2143                 rvt_get_qp(qp);
2144                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
2145         }
2146         return;
2147
2148 nack_acc_unlck:
2149         spin_unlock_irqrestore(&qp->s_lock, flags);
2150 nack_acc:
2151         rvt_rc_error(qp, IB_WC_LOC_PROT_ERR);
2152         qp->r_nak_state = IB_NAK_REMOTE_ACCESS_ERROR;
2153         qp->r_ack_psn = qp->r_psn;
2154 send_ack:
2155         qib_send_rc_ack(qp);
2156         return;
2157
2158 sunlock:
2159         spin_unlock_irqrestore(&qp->s_lock, flags);
2160 }