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 & RVT_MSN_MASK) |
 191                                             (qp->s_nak_state <<
 192                                              RVT_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 (qp->remote_ah_attr.ah_flags & 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(qp->remote_ah_attr.ah_flags & IB_AH_GRH)) {
 641                 hwords += qib_make_grh(ibp, &hdr.u.l.grh,
 642                                        &qp->remote_ah_attr.grh, hwords, 0);
 643                 ohdr = &hdr.u.l.oth;
 644                 lrh0 = QIB_LRH_GRH;
 645         }
 646         /* read pkey_index w/o lock (its atomic) */
 647         bth0 = qib_get_pkey(ibp, qp->s_pkey_index) | (OP(ACKNOWLEDGE) << 24);
 648         if (qp->s_mig_state == IB_MIG_MIGRATED)
 649                 bth0 |= IB_BTH_MIG_REQ;
 650         if (qp->r_nak_state)
 651                 ohdr->u.aeth = cpu_to_be32((qp->r_msn & RVT_MSN_MASK) |
 652                                             (qp->r_nak_state <<
 653                                              RVT_AETH_CREDIT_SHIFT));
 654         else
 655                 ohdr->u.aeth = rvt_compute_aeth(qp);
 656         lrh0 |= ibp->sl_to_vl[qp->remote_ah_attr.sl] << 12 |
 657                 qp->remote_ah_attr.sl << 4;
 658         hdr.lrh[0] = cpu_to_be16(lrh0);
 659         hdr.lrh[1] = cpu_to_be16(qp->remote_ah_attr.dlid);
 660         hdr.lrh[2] = cpu_to_be16(hwords + SIZE_OF_CRC);
 661         hdr.lrh[3] = cpu_to_be16(ppd->lid | qp->remote_ah_attr.src_path_bits);
 662         ohdr->bth[0] = cpu_to_be32(bth0);
 663         ohdr->bth[1] = cpu_to_be32(qp->remote_qpn);
 664         ohdr->bth[2] = cpu_to_be32(qp->r_ack_psn & QIB_PSN_MASK);
 665
 666         spin_unlock_irqrestore(&qp->s_lock, flags);
 667
 668         /* Don't try to send ACKs if the link isn't ACTIVE */
 669         if (!(ppd->lflags & QIBL_LINKACTIVE))
 670                 goto done;
 671
 672         control = dd->f_setpbc_control(ppd, hwords + SIZE_OF_CRC,
 673                                        qp->s_srate, lrh0 >> 12);
 674         /* length is + 1 for the control dword */
 675         pbc = ((u64) control << 32) | (hwords + 1);
 676
 677         piobuf = dd->f_getsendbuf(ppd, pbc, &pbufn);
 678         if (!piobuf) {
 679                 /*
 680                  * We are out of PIO buffers at the moment.
 681                  * Pass responsibility for sending the ACK to the
 682                  * send tasklet so that when a PIO buffer becomes
 683                  * available, the ACK is sent ahead of other outgoing
 684                  * packets.
 685                  */
 686                 spin_lock_irqsave(&qp->s_lock, flags);
 687                 goto queue_ack;
 688         }
 689
 690         /*
 691          * Write the pbc.
 692          * We have to flush after the PBC for correctness
 693          * on some cpus or WC buffer can be written out of order.
 694          */
 695         writeq(pbc, piobuf);
 696
 697         if (dd->flags & QIB_PIO_FLUSH_WC) {
 698                 u32 *hdrp = (u32 *) &hdr;
 699
 700                 qib_flush_wc();
 701                 qib_pio_copy(piobuf + 2, hdrp, hwords - 1);
 702                 qib_flush_wc();
 703                 __raw_writel(hdrp[hwords - 1], piobuf + hwords + 1);
 704         } else
 705                 qib_pio_copy(piobuf + 2, (u32 *) &hdr, hwords);
 706
 707         if (dd->flags & QIB_USE_SPCL_TRIG) {
 708                 u32 spcl_off = (pbufn >= dd->piobcnt2k) ? 2047 : 1023;
 709
 710                 qib_flush_wc();
 711                 __raw_writel(0xaebecede, piobuf + spcl_off);
 712         }
 713
 714         qib_flush_wc();
 715         qib_sendbuf_done(dd, pbufn);
 716
 717         this_cpu_inc(ibp->pmastats->n_unicast_xmit);
 718         goto done;
 719
 720 queue_ack:
 721         if (ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK) {
 722                 this_cpu_inc(*ibp->rvp.rc_qacks);
 723                 qp->s_flags |= RVT_S_ACK_PENDING | RVT_S_RESP_PENDING;
 724                 qp->s_nak_state = qp->r_nak_state;
 725                 qp->s_ack_psn = qp->r_ack_psn;
 726
 727                 /* Schedule the send tasklet. */
 728                 qib_schedule_send(qp);
 729         }
 730 unlock:
 731         spin_unlock_irqrestore(&qp->s_lock, flags);
 732 done:
 733         return;
 734 }
 735
 736 /**
 737  * reset_psn - reset the QP state to send starting from PSN
 738  * @qp: the QP
 739  * @psn: the packet sequence number to restart at
 740  *
 741  * This is called from qib_rc_rcv() to process an incoming RC ACK
 742  * for the given QP.
 743  * Called at interrupt level with the QP s_lock held.
 744  */
 745 static void reset_psn(struct rvt_qp *qp, u32 psn)
 746 {
 747         u32 n = qp->s_acked;
 748         struct rvt_swqe *wqe = rvt_get_swqe_ptr(qp, n);
 749         u32 opcode;
 750
 751         qp->s_cur = n;
 752
 753         /*
 754          * If we are starting the request from the beginning,
 755          * let the normal send code handle initialization.
 756          */
 757         if (qib_cmp24(psn, wqe->psn) <= 0) {
 758                 qp->s_state = OP(SEND_LAST);
 759                 goto done;
 760         }
 761
 762         /* Find the work request opcode corresponding to the given PSN. */
 763         opcode = wqe->wr.opcode;
 764         for (;;) {
 765                 int diff;
 766
 767                 if (++n == qp->s_size)
 768                         n = 0;
 769                 if (n == qp->s_tail)
 770                         break;
 771                 wqe = rvt_get_swqe_ptr(qp, n);
 772                 diff = qib_cmp24(psn, wqe->psn);
 773                 if (diff < 0)
 774                         break;
 775                 qp->s_cur = n;
 776                 /*
 777                  * If we are starting the request from the beginning,
 778                  * let the normal send code handle initialization.
 779                  */
 780                 if (diff == 0) {
 781                         qp->s_state = OP(SEND_LAST);
 782                         goto done;
 783                 }
 784                 opcode = wqe->wr.opcode;
 785         }
 786
 787         /*
 788          * Set the state to restart in the middle of a request.
 789          * Don't change the s_sge, s_cur_sge, or s_cur_size.
 790          * See qib_make_rc_req().
 791          */
 792         switch (opcode) {
 793         case IB_WR_SEND:
 794         case IB_WR_SEND_WITH_IMM:
 795                 qp->s_state = OP(RDMA_READ_RESPONSE_FIRST);
 796                 break;
 797
 798         case IB_WR_RDMA_WRITE:
 799         case IB_WR_RDMA_WRITE_WITH_IMM:
 800                 qp->s_state = OP(RDMA_READ_RESPONSE_LAST);
 801                 break;
 802
 803         case IB_WR_RDMA_READ:
 804                 qp->s_state = OP(RDMA_READ_RESPONSE_MIDDLE);
 805                 break;
 806
 807         default:
 808                 /*
 809                  * This case shouldn't happen since its only
 810                  * one PSN per req.
 811                  */
 812                 qp->s_state = OP(SEND_LAST);
 813         }
 814 done:
 815         qp->s_psn = psn;
 816         /*
 817          * Set RVT_S_WAIT_PSN as qib_rc_complete() may start the timer
 818          * asynchronously before the send tasklet can get scheduled.
 819          * Doing it in qib_make_rc_req() is too late.
 820          */
 821         if ((qib_cmp24(qp->s_psn, qp->s_sending_hpsn) <= 0) &&
 822             (qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) <= 0))
 823                 qp->s_flags |= RVT_S_WAIT_PSN;
 824 }
 825
 826 /*
 827  * Back up requester to resend the last un-ACKed request.
 828  * The QP r_lock and s_lock should be held and interrupts disabled.
 829  */
 830 void qib_restart_rc(struct rvt_qp *qp, u32 psn, int wait)
 831 {
 832         struct rvt_swqe *wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
 833         struct qib_ibport *ibp;
 834
 835         if (qp->s_retry == 0) {
 836                 if (qp->s_mig_state == IB_MIG_ARMED) {
 837                         qib_migrate_qp(qp);
 838                         qp->s_retry = qp->s_retry_cnt;
 839                 } else if (qp->s_last == qp->s_acked) {
 840                         qib_send_complete(qp, wqe, IB_WC_RETRY_EXC_ERR);
 841                         rvt_error_qp(qp, IB_WC_WR_FLUSH_ERR);
 842                         return;
 843                 } else /* XXX need to handle delayed completion */
 844                         return;
 845         } else
 846                 qp->s_retry--;
 847
 848         ibp = to_iport(qp->ibqp.device, qp->port_num);
 849         if (wqe->wr.opcode == IB_WR_RDMA_READ)
 850                 ibp->rvp.n_rc_resends++;
 851         else
 852                 ibp->rvp.n_rc_resends += (qp->s_psn - psn) & QIB_PSN_MASK;
 853
 854         qp->s_flags &= ~(RVT_S_WAIT_FENCE | RVT_S_WAIT_RDMAR |
 855                          RVT_S_WAIT_SSN_CREDIT | RVT_S_WAIT_PSN |
 856                          RVT_S_WAIT_ACK);
 857         if (wait)
 858                 qp->s_flags |= RVT_S_SEND_ONE;
 859         reset_psn(qp, psn);
 860 }
 861
 862 /*
 863  * Set qp->s_sending_psn to the next PSN after the given one.
 864  * This would be psn+1 except when RDMA reads are present.
 865  */
 866 static void reset_sending_psn(struct rvt_qp *qp, u32 psn)
 867 {
 868         struct rvt_swqe *wqe;
 869         u32 n = qp->s_last;
 870
 871         /* Find the work request corresponding to the given PSN. */
 872         for (;;) {
 873                 wqe = rvt_get_swqe_ptr(qp, n);
 874                 if (qib_cmp24(psn, wqe->lpsn) <= 0) {
 875                         if (wqe->wr.opcode == IB_WR_RDMA_READ)
 876                                 qp->s_sending_psn = wqe->lpsn + 1;
 877                         else
 878                                 qp->s_sending_psn = psn + 1;
 879                         break;
 880                 }
 881                 if (++n == qp->s_size)
 882                         n = 0;
 883                 if (n == qp->s_tail)
 884                         break;
 885         }
 886 }
 887
 888 /*
 889  * This should be called with the QP s_lock held and interrupts disabled.
 890  */
 891 void qib_rc_send_complete(struct rvt_qp *qp, struct ib_header *hdr)
 892 {
 893         struct ib_other_headers *ohdr;
 894         struct rvt_swqe *wqe;
 895         u32 opcode;
 896         u32 psn;
 897
 898         if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_OR_FLUSH_SEND))
 899                 return;
 900
 901         /* Find out where the BTH is */
 902         if ((be16_to_cpu(hdr->lrh[0]) & 3) == QIB_LRH_BTH)
 903                 ohdr = &hdr->u.oth;
 904         else
 905                 ohdr = &hdr->u.l.oth;
 906
 907         opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
 908         if (opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
 909             opcode <= OP(ATOMIC_ACKNOWLEDGE)) {
 910                 WARN_ON(!qp->s_rdma_ack_cnt);
 911                 qp->s_rdma_ack_cnt--;
 912                 return;
 913         }
 914
 915         psn = be32_to_cpu(ohdr->bth[2]);
 916         reset_sending_psn(qp, psn);
 917
 918         /*
 919          * Start timer after a packet requesting an ACK has been sent and
 920          * there are still requests that haven't been acked.
 921          */
 922         if ((psn & IB_BTH_REQ_ACK) && qp->s_acked != qp->s_tail &&
 923             !(qp->s_flags & (RVT_S_TIMER | RVT_S_WAIT_RNR | RVT_S_WAIT_PSN)) &&
 924             (ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK))
 925                 rvt_add_retry_timer(qp);
 926
 927         while (qp->s_last != qp->s_acked) {
 928                 u32 s_last;
 929
 930                 wqe = rvt_get_swqe_ptr(qp, qp->s_last);
 931                 if (qib_cmp24(wqe->lpsn, qp->s_sending_psn) >= 0 &&
 932                     qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) <= 0)
 933                         break;
 934                 s_last = qp->s_last;
 935                 if (++s_last >= qp->s_size)
 936                         s_last = 0;
 937                 qp->s_last = s_last;
 938                 /* see post_send() */
 939                 barrier();
 940                 rvt_put_swqe(wqe);
 941                 rvt_qp_swqe_complete(qp, wqe, IB_WC_SUCCESS);
 942         }
 943         /*
 944          * If we were waiting for sends to complete before resending,
 945          * and they are now complete, restart sending.
 946          */
 947         if (qp->s_flags & RVT_S_WAIT_PSN &&
 948             qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) > 0) {
 949                 qp->s_flags &= ~RVT_S_WAIT_PSN;
 950                 qp->s_sending_psn = qp->s_psn;
 951                 qp->s_sending_hpsn = qp->s_psn - 1;
 952                 qib_schedule_send(qp);
 953         }
 954 }
 955
 956 static inline void update_last_psn(struct rvt_qp *qp, u32 psn)
 957 {
 958         qp->s_last_psn = psn;
 959 }
 960
 961 /*
 962  * Generate a SWQE completion.
 963  * This is similar to qib_send_complete but has to check to be sure
 964  * that the SGEs are not being referenced if the SWQE is being resent.
 965  */
 966 static struct rvt_swqe *do_rc_completion(struct rvt_qp *qp,
 967                                          struct rvt_swqe *wqe,
 968                                          struct qib_ibport *ibp)
 969 {
 970         /*
 971          * Don't decrement refcount and don't generate a
 972          * completion if the SWQE is being resent until the send
 973          * is finished.
 974          */
 975         if (qib_cmp24(wqe->lpsn, qp->s_sending_psn) < 0 ||
 976             qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) > 0) {
 977                 u32 s_last;
 978
 979                 rvt_put_swqe(wqe);
 980                 s_last = qp->s_last;
 981                 if (++s_last >= qp->s_size)
 982                         s_last = 0;
 983                 qp->s_last = s_last;
 984                 /* see post_send() */
 985                 barrier();
 986                 rvt_qp_swqe_complete(qp, wqe, IB_WC_SUCCESS);
 987         } else
 988                 this_cpu_inc(*ibp->rvp.rc_delayed_comp);
 989
 990         qp->s_retry = qp->s_retry_cnt;
 991         update_last_psn(qp, wqe->lpsn);
 992
 993         /*
 994          * If we are completing a request which is in the process of
 995          * being resent, we can stop resending it since we know the
 996          * responder has already seen it.
 997          */
 998         if (qp->s_acked == qp->s_cur) {
 999                 if (++qp->s_cur >= qp->s_size)
1000                         qp->s_cur = 0;
1001                 qp->s_acked = qp->s_cur;
1002                 wqe = rvt_get_swqe_ptr(qp, qp->s_cur);
1003                 if (qp->s_acked != qp->s_tail) {
1004                         qp->s_state = OP(SEND_LAST);
1005                         qp->s_psn = wqe->psn;
1006                 }
1007         } else {
1008                 if (++qp->s_acked >= qp->s_size)
1009                         qp->s_acked = 0;
1010                 if (qp->state == IB_QPS_SQD && qp->s_acked == qp->s_cur)
1011                         qp->s_draining = 0;
1012                 wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1013         }
1014         return wqe;
1015 }
1016
1017 /**
1018  * do_rc_ack - process an incoming RC ACK
1019  * @qp: the QP the ACK came in on
1020  * @psn: the packet sequence number of the ACK
1021  * @opcode: the opcode of the request that resulted in the ACK
1022  *
1023  * This is called from qib_rc_rcv_resp() to process an incoming RC ACK
1024  * for the given QP.
1025  * Called at interrupt level with the QP s_lock held.
1026  * Returns 1 if OK, 0 if current operation should be aborted (NAK).
1027  */
1028 static int do_rc_ack(struct rvt_qp *qp, u32 aeth, u32 psn, int opcode,
1029                      u64 val, struct qib_ctxtdata *rcd)
1030 {
1031         struct qib_ibport *ibp;
1032         enum ib_wc_status status;
1033         struct rvt_swqe *wqe;
1034         int ret = 0;
1035         u32 ack_psn;
1036         int diff;
1037
1038         /*
1039          * Note that NAKs implicitly ACK outstanding SEND and RDMA write
1040          * requests and implicitly NAK RDMA read and atomic requests issued
1041          * before the NAK'ed request.  The MSN won't include the NAK'ed
1042          * request but will include an ACK'ed request(s).
1043          */
1044         ack_psn = psn;
1045         if (aeth >> RVT_AETH_NAK_SHIFT)
1046                 ack_psn--;
1047         wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1048         ibp = to_iport(qp->ibqp.device, qp->port_num);
1049
1050         /*
1051          * The MSN might be for a later WQE than the PSN indicates so
1052          * only complete WQEs that the PSN finishes.
1053          */
1054         while ((diff = qib_cmp24(ack_psn, wqe->lpsn)) >= 0) {
1055                 /*
1056                  * RDMA_READ_RESPONSE_ONLY is a special case since
1057                  * we want to generate completion events for everything
1058                  * before the RDMA read, copy the data, then generate
1059                  * the completion for the read.
1060                  */
1061                 if (wqe->wr.opcode == IB_WR_RDMA_READ &&
1062                     opcode == OP(RDMA_READ_RESPONSE_ONLY) &&
1063                     diff == 0) {
1064                         ret = 1;
1065                         goto bail;
1066                 }
1067                 /*
1068                  * If this request is a RDMA read or atomic, and the ACK is
1069                  * for a later operation, this ACK NAKs the RDMA read or
1070                  * atomic.  In other words, only a RDMA_READ_LAST or ONLY
1071                  * can ACK a RDMA read and likewise for atomic ops.  Note
1072                  * that the NAK case can only happen if relaxed ordering is
1073                  * used and requests are sent after an RDMA read or atomic
1074                  * is sent but before the response is received.
1075                  */
1076                 if ((wqe->wr.opcode == IB_WR_RDMA_READ &&
1077                      (opcode != OP(RDMA_READ_RESPONSE_LAST) || diff != 0)) ||
1078                     ((wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1079                       wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) &&
1080                      (opcode != OP(ATOMIC_ACKNOWLEDGE) || diff != 0))) {
1081                         /* Retry this request. */
1082                         if (!(qp->r_flags & RVT_R_RDMAR_SEQ)) {
1083                                 qp->r_flags |= RVT_R_RDMAR_SEQ;
1084                                 qib_restart_rc(qp, qp->s_last_psn + 1, 0);
1085                                 if (list_empty(&qp->rspwait)) {
1086                                         qp->r_flags |= RVT_R_RSP_SEND;
1087                                         rvt_get_qp(qp);
1088                                         list_add_tail(&qp->rspwait,
1089                                                       &rcd->qp_wait_list);
1090                                 }
1091                         }
1092                         /*
1093                          * No need to process the ACK/NAK since we are
1094                          * restarting an earlier request.
1095                          */
1096                         goto bail;
1097                 }
1098                 if (wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1099                     wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) {
1100                         u64 *vaddr = wqe->sg_list[0].vaddr;
1101                         *vaddr = val;
1102                 }
1103                 if (qp->s_num_rd_atomic &&
1104                     (wqe->wr.opcode == IB_WR_RDMA_READ ||
1105                      wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1106                      wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)) {
1107                         qp->s_num_rd_atomic--;
1108                         /* Restart sending task if fence is complete */
1109                         if ((qp->s_flags & RVT_S_WAIT_FENCE) &&
1110                             !qp->s_num_rd_atomic) {
1111                                 qp->s_flags &= ~(RVT_S_WAIT_FENCE |
1112                                                  RVT_S_WAIT_ACK);
1113                                 qib_schedule_send(qp);
1114                         } else if (qp->s_flags & RVT_S_WAIT_RDMAR) {
1115                                 qp->s_flags &= ~(RVT_S_WAIT_RDMAR |
1116                                                  RVT_S_WAIT_ACK);
1117                                 qib_schedule_send(qp);
1118                         }
1119                 }
1120                 wqe = do_rc_completion(qp, wqe, ibp);
1121                 if (qp->s_acked == qp->s_tail)
1122                         break;
1123         }
1124
1125         switch (aeth >> RVT_AETH_NAK_SHIFT) {
1126         case 0:         /* ACK */
1127                 this_cpu_inc(*ibp->rvp.rc_acks);
1128                 if (qp->s_acked != qp->s_tail) {
1129                         /*
1130                          * We are expecting more ACKs so
1131                          * reset the retransmit timer.
1132                          */
1133                         rvt_mod_retry_timer(qp);
1134                         /*
1135                          * We can stop resending the earlier packets and
1136                          * continue with the next packet the receiver wants.
1137                          */
1138                         if (qib_cmp24(qp->s_psn, psn) <= 0)
1139                                 reset_psn(qp, psn + 1);
1140                 } else {
1141                         /* No more acks - kill all timers */
1142                         rvt_stop_rc_timers(qp);
1143                         if (qib_cmp24(qp->s_psn, psn) <= 0) {
1144                                 qp->s_state = OP(SEND_LAST);
1145                                 qp->s_psn = psn + 1;
1146                         }
1147                 }
1148                 if (qp->s_flags & RVT_S_WAIT_ACK) {
1149                         qp->s_flags &= ~RVT_S_WAIT_ACK;
1150                         qib_schedule_send(qp);
1151                 }
1152                 rvt_get_credit(qp, aeth);
1153                 qp->s_rnr_retry = qp->s_rnr_retry_cnt;
1154                 qp->s_retry = qp->s_retry_cnt;
1155                 update_last_psn(qp, psn);
1156                 return 1;
1157
1158         case 1:         /* RNR NAK */
1159                 ibp->rvp.n_rnr_naks++;
1160                 if (qp->s_acked == qp->s_tail)
1161                         goto bail;
1162                 if (qp->s_flags & RVT_S_WAIT_RNR)
1163                         goto bail;
1164                 if (qp->s_rnr_retry == 0) {
1165                         status = IB_WC_RNR_RETRY_EXC_ERR;
1166                         goto class_b;
1167                 }
1168                 if (qp->s_rnr_retry_cnt < 7)
1169                         qp->s_rnr_retry--;
1170
1171                 /* The last valid PSN is the previous PSN. */
1172                 update_last_psn(qp, psn - 1);
1173
1174                 ibp->rvp.n_rc_resends += (qp->s_psn - psn) & QIB_PSN_MASK;
1175
1176                 reset_psn(qp, psn);
1177
1178                 qp->s_flags &= ~(RVT_S_WAIT_SSN_CREDIT | RVT_S_WAIT_ACK);
1179                 rvt_stop_rc_timers(qp);
1180                 rvt_add_rnr_timer(qp, aeth);
1181                 return 0;
1182
1183         case 3:         /* NAK */
1184                 if (qp->s_acked == qp->s_tail)
1185                         goto bail;
1186                 /* The last valid PSN is the previous PSN. */
1187                 update_last_psn(qp, psn - 1);
1188                 switch ((aeth >> RVT_AETH_CREDIT_SHIFT) &
1189                         RVT_AETH_CREDIT_MASK) {
1190                 case 0: /* PSN sequence error */
1191                         ibp->rvp.n_seq_naks++;
1192                         /*
1193                          * Back up to the responder's expected PSN.
1194                          * Note that we might get a NAK in the middle of an
1195                          * RDMA READ response which terminates the RDMA
1196                          * READ.
1197                          */
1198                         qib_restart_rc(qp, psn, 0);
1199                         qib_schedule_send(qp);
1200                         break;
1201
1202                 case 1: /* Invalid Request */
1203                         status = IB_WC_REM_INV_REQ_ERR;
1204                         ibp->rvp.n_other_naks++;
1205                         goto class_b;
1206
1207                 case 2: /* Remote Access Error */
1208                         status = IB_WC_REM_ACCESS_ERR;
1209                         ibp->rvp.n_other_naks++;
1210                         goto class_b;
1211
1212                 case 3: /* Remote Operation Error */
1213                         status = IB_WC_REM_OP_ERR;
1214                         ibp->rvp.n_other_naks++;
1215 class_b:
1216                         if (qp->s_last == qp->s_acked) {
1217                                 qib_send_complete(qp, wqe, status);
1218                                 rvt_error_qp(qp, IB_WC_WR_FLUSH_ERR);
1219                         }
1220                         break;
1221
1222                 default:
1223                         /* Ignore other reserved NAK error codes */
1224                         goto reserved;
1225                 }
1226                 qp->s_retry = qp->s_retry_cnt;
1227                 qp->s_rnr_retry = qp->s_rnr_retry_cnt;
1228                 goto bail;
1229
1230         default:                /* 2: reserved */
1231 reserved:
1232                 /* Ignore reserved NAK codes. */
1233                 goto bail;
1234         }
1235
1236 bail:
1237         rvt_stop_rc_timers(qp);
1238         return ret;
1239 }
1240
1241 /*
1242  * We have seen an out of sequence RDMA read middle or last packet.
1243  * This ACKs SENDs and RDMA writes up to the first RDMA read or atomic SWQE.
1244  */
1245 static void rdma_seq_err(struct rvt_qp *qp, struct qib_ibport *ibp, u32 psn,
1246                          struct qib_ctxtdata *rcd)
1247 {
1248         struct rvt_swqe *wqe;
1249
1250         /* Remove QP from retry timer */
1251         rvt_stop_rc_timers(qp);
1252
1253         wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1254
1255         while (qib_cmp24(psn, wqe->lpsn) > 0) {
1256                 if (wqe->wr.opcode == IB_WR_RDMA_READ ||
1257                     wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1258                     wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)
1259                         break;
1260                 wqe = do_rc_completion(qp, wqe, ibp);
1261         }
1262
1263         ibp->rvp.n_rdma_seq++;
1264         qp->r_flags |= RVT_R_RDMAR_SEQ;
1265         qib_restart_rc(qp, qp->s_last_psn + 1, 0);
1266         if (list_empty(&qp->rspwait)) {
1267                 qp->r_flags |= RVT_R_RSP_SEND;
1268                 rvt_get_qp(qp);
1269                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
1270         }
1271 }
1272
1273 /**
1274  * qib_rc_rcv_resp - process an incoming RC response packet
1275  * @ibp: the port this packet came in on
1276  * @ohdr: the other headers for this packet
1277  * @data: the packet data
1278  * @tlen: the packet length
1279  * @qp: the QP for this packet
1280  * @opcode: the opcode for this packet
1281  * @psn: the packet sequence number for this packet
1282  * @hdrsize: the header length
1283  * @pmtu: the path MTU
1284  *
1285  * This is called from qib_rc_rcv() to process an incoming RC response
1286  * packet for the given QP.
1287  * Called at interrupt level.
1288  */
1289 static void qib_rc_rcv_resp(struct qib_ibport *ibp,
1290                             struct ib_other_headers *ohdr,
1291                             void *data, u32 tlen,
1292                             struct rvt_qp *qp,
1293                             u32 opcode,
1294                             u32 psn, u32 hdrsize, u32 pmtu,
1295                             struct qib_ctxtdata *rcd)
1296 {
1297         struct rvt_swqe *wqe;
1298         struct qib_pportdata *ppd = ppd_from_ibp(ibp);
1299         enum ib_wc_status status;
1300         unsigned long flags;
1301         int diff;
1302         u32 pad;
1303         u32 aeth;
1304         u64 val;
1305
1306         if (opcode != OP(RDMA_READ_RESPONSE_MIDDLE)) {
1307                 /*
1308                  * If ACK'd PSN on SDMA busy list try to make progress to
1309                  * reclaim SDMA credits.
1310                  */
1311                 if ((qib_cmp24(psn, qp->s_sending_psn) >= 0) &&
1312                     (qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) <= 0)) {
1313
1314                         /*
1315                          * If send tasklet not running attempt to progress
1316                          * SDMA queue.
1317                          */
1318                         if (!(qp->s_flags & RVT_S_BUSY)) {
1319                                 /* Acquire SDMA Lock */
1320                                 spin_lock_irqsave(&ppd->sdma_lock, flags);
1321                                 /* Invoke sdma make progress */
1322                                 qib_sdma_make_progress(ppd);
1323                                 /* Release SDMA Lock */
1324                                 spin_unlock_irqrestore(&ppd->sdma_lock, flags);
1325                         }
1326                 }
1327         }
1328
1329         spin_lock_irqsave(&qp->s_lock, flags);
1330         if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK))
1331                 goto ack_done;
1332
1333         /* Ignore invalid responses. */
1334         smp_read_barrier_depends(); /* see post_one_send */
1335         if (qib_cmp24(psn, READ_ONCE(qp->s_next_psn)) >= 0)
1336                 goto ack_done;
1337
1338         /* Ignore duplicate responses. */
1339         diff = qib_cmp24(psn, qp->s_last_psn);
1340         if (unlikely(diff <= 0)) {
1341                 /* Update credits for "ghost" ACKs */
1342                 if (diff == 0 && opcode == OP(ACKNOWLEDGE)) {
1343                         aeth = be32_to_cpu(ohdr->u.aeth);
1344                         if ((aeth >> RVT_AETH_NAK_SHIFT) == 0)
1345                                 rvt_get_credit(qp, aeth);
1346                 }
1347                 goto ack_done;
1348         }
1349
1350         /*
1351          * Skip everything other than the PSN we expect, if we are waiting
1352          * for a reply to a restarted RDMA read or atomic op.
1353          */
1354         if (qp->r_flags & RVT_R_RDMAR_SEQ) {
1355                 if (qib_cmp24(psn, qp->s_last_psn + 1) != 0)
1356                         goto ack_done;
1357                 qp->r_flags &= ~RVT_R_RDMAR_SEQ;
1358         }
1359
1360         if (unlikely(qp->s_acked == qp->s_tail))
1361                 goto ack_done;
1362         wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1363         status = IB_WC_SUCCESS;
1364
1365         switch (opcode) {
1366         case OP(ACKNOWLEDGE):
1367         case OP(ATOMIC_ACKNOWLEDGE):
1368         case OP(RDMA_READ_RESPONSE_FIRST):
1369                 aeth = be32_to_cpu(ohdr->u.aeth);
1370                 if (opcode == OP(ATOMIC_ACKNOWLEDGE))
1371                         val = ib_u64_get(&ohdr->u.at.atomic_ack_eth);
1372                 else
1373                         val = 0;
1374                 if (!do_rc_ack(qp, aeth, psn, opcode, val, rcd) ||
1375                     opcode != OP(RDMA_READ_RESPONSE_FIRST))
1376                         goto ack_done;
1377                 hdrsize += 4;
1378                 wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1379                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1380                         goto ack_op_err;
1381                 /*
1382                  * If this is a response to a resent RDMA read, we
1383                  * have to be careful to copy the data to the right
1384                  * location.
1385                  */
1386                 qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
1387                                                   wqe, psn, pmtu);
1388                 goto read_middle;
1389
1390         case OP(RDMA_READ_RESPONSE_MIDDLE):
1391                 /* no AETH, no ACK */
1392                 if (unlikely(qib_cmp24(psn, qp->s_last_psn + 1)))
1393                         goto ack_seq_err;
1394                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1395                         goto ack_op_err;
1396 read_middle:
1397                 if (unlikely(tlen != (hdrsize + pmtu + 4)))
1398                         goto ack_len_err;
1399                 if (unlikely(pmtu >= qp->s_rdma_read_len))
1400                         goto ack_len_err;
1401
1402                 /*
1403                  * We got a response so update the timeout.
1404                  * 4.096 usec. * (1 << qp->timeout)
1405                  */
1406                 rvt_mod_retry_timer(qp);
1407                 if (qp->s_flags & RVT_S_WAIT_ACK) {
1408                         qp->s_flags &= ~RVT_S_WAIT_ACK;
1409                         qib_schedule_send(qp);
1410                 }
1411
1412                 if (opcode == OP(RDMA_READ_RESPONSE_MIDDLE))
1413                         qp->s_retry = qp->s_retry_cnt;
1414
1415                 /*
1416                  * Update the RDMA receive state but do the copy w/o
1417                  * holding the locks and blocking interrupts.
1418                  */
1419                 qp->s_rdma_read_len -= pmtu;
1420                 update_last_psn(qp, psn);
1421                 spin_unlock_irqrestore(&qp->s_lock, flags);
1422                 qib_copy_sge(&qp->s_rdma_read_sge, data, pmtu, 0);
1423                 goto bail;
1424
1425         case OP(RDMA_READ_RESPONSE_ONLY):
1426                 aeth = be32_to_cpu(ohdr->u.aeth);
1427                 if (!do_rc_ack(qp, aeth, psn, opcode, 0, rcd))
1428                         goto ack_done;
1429                 /* Get the number of bytes the message was padded by. */
1430                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1431                 /*
1432                  * Check that the data size is >= 0 && <= pmtu.
1433                  * Remember to account for the AETH header (4) and
1434                  * ICRC (4).
1435                  */
1436                 if (unlikely(tlen < (hdrsize + pad + 8)))
1437                         goto ack_len_err;
1438                 /*
1439                  * If this is a response to a resent RDMA read, we
1440                  * have to be careful to copy the data to the right
1441                  * location.
1442                  */
1443                 wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1444                 qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
1445                                                   wqe, psn, pmtu);
1446                 goto read_last;
1447
1448         case OP(RDMA_READ_RESPONSE_LAST):
1449                 /* ACKs READ req. */
1450                 if (unlikely(qib_cmp24(psn, qp->s_last_psn + 1)))
1451                         goto ack_seq_err;
1452                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1453                         goto ack_op_err;
1454                 /* Get the number of bytes the message was padded by. */
1455                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1456                 /*
1457                  * Check that the data size is >= 1 && <= pmtu.
1458                  * Remember to account for the AETH header (4) and
1459                  * ICRC (4).
1460                  */
1461                 if (unlikely(tlen <= (hdrsize + pad + 8)))
1462                         goto ack_len_err;
1463 read_last:
1464                 tlen -= hdrsize + pad + 8;
1465                 if (unlikely(tlen != qp->s_rdma_read_len))
1466                         goto ack_len_err;
1467                 aeth = be32_to_cpu(ohdr->u.aeth);
1468                 qib_copy_sge(&qp->s_rdma_read_sge, data, tlen, 0);
1469                 WARN_ON(qp->s_rdma_read_sge.num_sge);
1470                 (void) do_rc_ack(qp, aeth, psn,
1471                                  OP(RDMA_READ_RESPONSE_LAST), 0, rcd);
1472                 goto ack_done;
1473         }
1474
1475 ack_op_err:
1476         status = IB_WC_LOC_QP_OP_ERR;
1477         goto ack_err;
1478
1479 ack_seq_err:
1480         rdma_seq_err(qp, ibp, psn, rcd);
1481         goto ack_done;
1482
1483 ack_len_err:
1484         status = IB_WC_LOC_LEN_ERR;
1485 ack_err:
1486         if (qp->s_last == qp->s_acked) {
1487                 qib_send_complete(qp, wqe, status);
1488                 rvt_error_qp(qp, IB_WC_WR_FLUSH_ERR);
1489         }
1490 ack_done:
1491         spin_unlock_irqrestore(&qp->s_lock, flags);
1492 bail:
1493         return;
1494 }
1495
1496 /**
1497  * qib_rc_rcv_error - process an incoming duplicate or error RC packet
1498  * @ohdr: the other headers for this packet
1499  * @data: the packet data
1500  * @qp: the QP for this packet
1501  * @opcode: the opcode for this packet
1502  * @psn: the packet sequence number for this packet
1503  * @diff: the difference between the PSN and the expected PSN
1504  *
1505  * This is called from qib_rc_rcv() to process an unexpected
1506  * incoming RC packet for the given QP.
1507  * Called at interrupt level.
1508  * Return 1 if no more processing is needed; otherwise return 0 to
1509  * schedule a response to be sent.
1510  */
1511 static int qib_rc_rcv_error(struct ib_other_headers *ohdr,
1512                             void *data,
1513                             struct rvt_qp *qp,
1514                             u32 opcode,
1515                             u32 psn,
1516                             int diff,
1517                             struct qib_ctxtdata *rcd)
1518 {
1519         struct qib_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
1520         struct rvt_ack_entry *e;
1521         unsigned long flags;
1522         u8 i, prev;
1523         int old_req;
1524
1525         if (diff > 0) {
1526                 /*
1527                  * Packet sequence error.
1528                  * A NAK will ACK earlier sends and RDMA writes.
1529                  * Don't queue the NAK if we already sent one.
1530                  */
1531                 if (!qp->r_nak_state) {
1532                         ibp->rvp.n_rc_seqnak++;
1533                         qp->r_nak_state = IB_NAK_PSN_ERROR;
1534                         /* Use the expected PSN. */
1535                         qp->r_ack_psn = qp->r_psn;
1536                         /*
1537                          * Wait to send the sequence NAK until all packets
1538                          * in the receive queue have been processed.
1539                          * Otherwise, we end up propagating congestion.
1540                          */
1541                         if (list_empty(&qp->rspwait)) {
1542                                 qp->r_flags |= RVT_R_RSP_NAK;
1543                                 rvt_get_qp(qp);
1544                                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
1545                         }
1546                 }
1547                 goto done;
1548         }
1549
1550         /*
1551          * Handle a duplicate request.  Don't re-execute SEND, RDMA
1552          * write or atomic op.  Don't NAK errors, just silently drop
1553          * the duplicate request.  Note that r_sge, r_len, and
1554          * r_rcv_len may be in use so don't modify them.
1555          *
1556          * We are supposed to ACK the earliest duplicate PSN but we
1557          * can coalesce an outstanding duplicate ACK.  We have to
1558          * send the earliest so that RDMA reads can be restarted at
1559          * the requester's expected PSN.
1560          *
1561          * First, find where this duplicate PSN falls within the
1562          * ACKs previously sent.
1563          * old_req is true if there is an older response that is scheduled
1564          * to be sent before sending this one.
1565          */
1566         e = NULL;
1567         old_req = 1;
1568         ibp->rvp.n_rc_dupreq++;
1569
1570         spin_lock_irqsave(&qp->s_lock, flags);
1571
1572         for (i = qp->r_head_ack_queue; ; i = prev) {
1573                 if (i == qp->s_tail_ack_queue)
1574                         old_req = 0;
1575                 if (i)
1576                         prev = i - 1;
1577                 else
1578                         prev = QIB_MAX_RDMA_ATOMIC;
1579                 if (prev == qp->r_head_ack_queue) {
1580                         e = NULL;
1581                         break;
1582                 }
1583                 e = &qp->s_ack_queue[prev];
1584                 if (!e->opcode) {
1585                         e = NULL;
1586                         break;
1587                 }
1588                 if (qib_cmp24(psn, e->psn) >= 0) {
1589                         if (prev == qp->s_tail_ack_queue &&
1590                             qib_cmp24(psn, e->lpsn) <= 0)
1591                                 old_req = 0;
1592                         break;
1593                 }
1594         }
1595         switch (opcode) {
1596         case OP(RDMA_READ_REQUEST): {
1597                 struct ib_reth *reth;
1598                 u32 offset;
1599                 u32 len;
1600
1601                 /*
1602                  * If we didn't find the RDMA read request in the ack queue,
1603                  * we can ignore this request.
1604                  */
1605                 if (!e || e->opcode != OP(RDMA_READ_REQUEST))
1606                         goto unlock_done;
1607                 /* RETH comes after BTH */
1608                 reth = &ohdr->u.rc.reth;
1609                 /*
1610                  * Address range must be a subset of the original
1611                  * request and start on pmtu boundaries.
1612                  * We reuse the old ack_queue slot since the requester
1613                  * should not back up and request an earlier PSN for the
1614                  * same request.
1615                  */
1616                 offset = ((psn - e->psn) & QIB_PSN_MASK) *
1617                         qp->pmtu;
1618                 len = be32_to_cpu(reth->length);
1619                 if (unlikely(offset + len != e->rdma_sge.sge_length))
1620                         goto unlock_done;
1621                 if (e->rdma_sge.mr) {
1622                         rvt_put_mr(e->rdma_sge.mr);
1623                         e->rdma_sge.mr = NULL;
1624                 }
1625                 if (len != 0) {
1626                         u32 rkey = be32_to_cpu(reth->rkey);
1627                         u64 vaddr = be64_to_cpu(reth->vaddr);
1628                         int ok;
1629
1630                         ok = rvt_rkey_ok(qp, &e->rdma_sge, len, vaddr, rkey,
1631                                          IB_ACCESS_REMOTE_READ);
1632                         if (unlikely(!ok))
1633                                 goto unlock_done;
1634                 } else {
1635                         e->rdma_sge.vaddr = NULL;
1636                         e->rdma_sge.length = 0;
1637                         e->rdma_sge.sge_length = 0;
1638                 }
1639                 e->psn = psn;
1640                 if (old_req)
1641                         goto unlock_done;
1642                 qp->s_tail_ack_queue = prev;
1643                 break;
1644         }
1645
1646         case OP(COMPARE_SWAP):
1647         case OP(FETCH_ADD): {
1648                 /*
1649                  * If we didn't find the atomic request in the ack queue
1650                  * or the send tasklet is already backed up to send an
1651                  * earlier entry, we can ignore this request.
1652                  */
1653                 if (!e || e->opcode != (u8) opcode || old_req)
1654                         goto unlock_done;
1655                 qp->s_tail_ack_queue = prev;
1656                 break;
1657         }
1658
1659         default:
1660                 /*
1661                  * Ignore this operation if it doesn't request an ACK
1662                  * or an earlier RDMA read or atomic is going to be resent.
1663                  */
1664                 if (!(psn & IB_BTH_REQ_ACK) || old_req)
1665                         goto unlock_done;
1666                 /*
1667                  * Resend the most recent ACK if this request is
1668                  * after all the previous RDMA reads and atomics.
1669                  */
1670                 if (i == qp->r_head_ack_queue) {
1671                         spin_unlock_irqrestore(&qp->s_lock, flags);
1672                         qp->r_nak_state = 0;
1673                         qp->r_ack_psn = qp->r_psn - 1;
1674                         goto send_ack;
1675                 }
1676                 /*
1677                  * Try to send a simple ACK to work around a Mellanox bug
1678                  * which doesn't accept a RDMA read response or atomic
1679                  * response as an ACK for earlier SENDs or RDMA writes.
1680                  */
1681                 if (!(qp->s_flags & RVT_S_RESP_PENDING)) {
1682                         spin_unlock_irqrestore(&qp->s_lock, flags);
1683                         qp->r_nak_state = 0;
1684                         qp->r_ack_psn = qp->s_ack_queue[i].psn - 1;
1685                         goto send_ack;
1686                 }
1687                 /*
1688                  * Resend the RDMA read or atomic op which
1689                  * ACKs this duplicate request.
1690                  */
1691                 qp->s_tail_ack_queue = i;
1692                 break;
1693         }
1694         qp->s_ack_state = OP(ACKNOWLEDGE);
1695         qp->s_flags |= RVT_S_RESP_PENDING;
1696         qp->r_nak_state = 0;
1697         qib_schedule_send(qp);
1698
1699 unlock_done:
1700         spin_unlock_irqrestore(&qp->s_lock, flags);
1701 done:
1702         return 1;
1703
1704 send_ack:
1705         return 0;
1706 }
1707
1708 static inline void qib_update_ack_queue(struct rvt_qp *qp, unsigned n)
1709 {
1710         unsigned next;
1711
1712         next = n + 1;
1713         if (next > QIB_MAX_RDMA_ATOMIC)
1714                 next = 0;
1715         qp->s_tail_ack_queue = next;
1716         qp->s_ack_state = OP(ACKNOWLEDGE);
1717 }
1718
1719 /**
1720  * qib_rc_rcv - process an incoming RC packet
1721  * @rcd: the context pointer
1722  * @hdr: the header of this packet
1723  * @has_grh: true if the header has a GRH
1724  * @data: the packet data
1725  * @tlen: the packet length
1726  * @qp: the QP for this packet
1727  *
1728  * This is called from qib_qp_rcv() to process an incoming RC packet
1729  * for the given QP.
1730  * Called at interrupt level.
1731  */
1732 void qib_rc_rcv(struct qib_ctxtdata *rcd, struct ib_header *hdr,
1733                 int has_grh, void *data, u32 tlen, struct rvt_qp *qp)
1734 {
1735         struct qib_ibport *ibp = &rcd->ppd->ibport_data;
1736         struct ib_other_headers *ohdr;
1737         u32 opcode;
1738         u32 hdrsize;
1739         u32 psn;
1740         u32 pad;
1741         struct ib_wc wc;
1742         u32 pmtu = qp->pmtu;
1743         int diff;
1744         struct ib_reth *reth;
1745         unsigned long flags;
1746         int ret;
1747
1748         /* Check for GRH */
1749         if (!has_grh) {
1750                 ohdr = &hdr->u.oth;
1751                 hdrsize = 8 + 12;       /* LRH + BTH */
1752         } else {
1753                 ohdr = &hdr->u.l.oth;
1754                 hdrsize = 8 + 40 + 12;  /* LRH + GRH + BTH */
1755         }
1756
1757         opcode = be32_to_cpu(ohdr->bth[0]);
1758         if (qib_ruc_check_hdr(ibp, hdr, has_grh, qp, opcode))
1759                 return;
1760
1761         psn = be32_to_cpu(ohdr->bth[2]);
1762         opcode >>= 24;
1763
1764         /*
1765          * Process responses (ACKs) before anything else.  Note that the
1766          * packet sequence number will be for something in the send work
1767          * queue rather than the expected receive packet sequence number.
1768          * In other words, this QP is the requester.
1769          */
1770         if (opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
1771             opcode <= OP(ATOMIC_ACKNOWLEDGE)) {
1772                 qib_rc_rcv_resp(ibp, ohdr, data, tlen, qp, opcode, psn,
1773                                 hdrsize, pmtu, rcd);
1774                 return;
1775         }
1776
1777         /* Compute 24 bits worth of difference. */
1778         diff = qib_cmp24(psn, qp->r_psn);
1779         if (unlikely(diff)) {
1780                 if (qib_rc_rcv_error(ohdr, data, qp, opcode, psn, diff, rcd))
1781                         return;
1782                 goto send_ack;
1783         }
1784
1785         /* Check for opcode sequence errors. */
1786         switch (qp->r_state) {
1787         case OP(SEND_FIRST):
1788         case OP(SEND_MIDDLE):
1789                 if (opcode == OP(SEND_MIDDLE) ||
1790                     opcode == OP(SEND_LAST) ||
1791                     opcode == OP(SEND_LAST_WITH_IMMEDIATE))
1792                         break;
1793                 goto nack_inv;
1794
1795         case OP(RDMA_WRITE_FIRST):
1796         case OP(RDMA_WRITE_MIDDLE):
1797                 if (opcode == OP(RDMA_WRITE_MIDDLE) ||
1798                     opcode == OP(RDMA_WRITE_LAST) ||
1799                     opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
1800                         break;
1801                 goto nack_inv;
1802
1803         default:
1804                 if (opcode == OP(SEND_MIDDLE) ||
1805                     opcode == OP(SEND_LAST) ||
1806                     opcode == OP(SEND_LAST_WITH_IMMEDIATE) ||
1807                     opcode == OP(RDMA_WRITE_MIDDLE) ||
1808                     opcode == OP(RDMA_WRITE_LAST) ||
1809                     opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
1810                         goto nack_inv;
1811                 /*
1812                  * Note that it is up to the requester to not send a new
1813                  * RDMA read or atomic operation before receiving an ACK
1814                  * for the previous operation.
1815                  */
1816                 break;
1817         }
1818
1819         if (qp->state == IB_QPS_RTR && !(qp->r_flags & RVT_R_COMM_EST))
1820                 rvt_comm_est(qp);
1821
1822         /* OK, process the packet. */
1823         switch (opcode) {
1824         case OP(SEND_FIRST):
1825                 ret = qib_get_rwqe(qp, 0);
1826                 if (ret < 0)
1827                         goto nack_op_err;
1828                 if (!ret)
1829                         goto rnr_nak;
1830                 qp->r_rcv_len = 0;
1831                 /* FALLTHROUGH */
1832         case OP(SEND_MIDDLE):
1833         case OP(RDMA_WRITE_MIDDLE):
1834 send_middle:
1835                 /* Check for invalid length PMTU or posted rwqe len. */
1836                 if (unlikely(tlen != (hdrsize + pmtu + 4)))
1837                         goto nack_inv;
1838                 qp->r_rcv_len += pmtu;
1839                 if (unlikely(qp->r_rcv_len > qp->r_len))
1840                         goto nack_inv;
1841                 qib_copy_sge(&qp->r_sge, data, pmtu, 1);
1842                 break;
1843
1844         case OP(RDMA_WRITE_LAST_WITH_IMMEDIATE):
1845                 /* consume RWQE */
1846                 ret = qib_get_rwqe(qp, 1);
1847                 if (ret < 0)
1848                         goto nack_op_err;
1849                 if (!ret)
1850                         goto rnr_nak;
1851                 goto send_last_imm;
1852
1853         case OP(SEND_ONLY):
1854         case OP(SEND_ONLY_WITH_IMMEDIATE):
1855                 ret = qib_get_rwqe(qp, 0);
1856                 if (ret < 0)
1857                         goto nack_op_err;
1858                 if (!ret)
1859                         goto rnr_nak;
1860                 qp->r_rcv_len = 0;
1861                 if (opcode == OP(SEND_ONLY))
1862                         goto no_immediate_data;
1863                 /* FALLTHROUGH for SEND_ONLY_WITH_IMMEDIATE */
1864         case OP(SEND_LAST_WITH_IMMEDIATE):
1865 send_last_imm:
1866                 wc.ex.imm_data = ohdr->u.imm_data;
1867                 hdrsize += 4;
1868                 wc.wc_flags = IB_WC_WITH_IMM;
1869                 goto send_last;
1870         case OP(SEND_LAST):
1871         case OP(RDMA_WRITE_LAST):
1872 no_immediate_data:
1873                 wc.wc_flags = 0;
1874                 wc.ex.imm_data = 0;
1875 send_last:
1876                 /* Get the number of bytes the message was padded by. */
1877                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1878                 /* Check for invalid length. */
1879                 /* XXX LAST len should be >= 1 */
1880                 if (unlikely(tlen < (hdrsize + pad + 4)))
1881                         goto nack_inv;
1882                 /* Don't count the CRC. */
1883                 tlen -= (hdrsize + pad + 4);
1884                 wc.byte_len = tlen + qp->r_rcv_len;
1885                 if (unlikely(wc.byte_len > qp->r_len))
1886                         goto nack_inv;
1887                 qib_copy_sge(&qp->r_sge, data, tlen, 1);
1888                 rvt_put_ss(&qp->r_sge);
1889                 qp->r_msn++;
1890                 if (!test_and_clear_bit(RVT_R_WRID_VALID, &qp->r_aflags))
1891                         break;
1892                 wc.wr_id = qp->r_wr_id;
1893                 wc.status = IB_WC_SUCCESS;
1894                 if (opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE) ||
1895                     opcode == OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE))
1896                         wc.opcode = IB_WC_RECV_RDMA_WITH_IMM;
1897                 else
1898                         wc.opcode = IB_WC_RECV;
1899                 wc.qp = &qp->ibqp;
1900                 wc.src_qp = qp->remote_qpn;
1901                 wc.slid = qp->remote_ah_attr.dlid;
1902                 wc.sl = qp->remote_ah_attr.sl;
1903                 /* zero fields that are N/A */
1904                 wc.vendor_err = 0;
1905                 wc.pkey_index = 0;
1906                 wc.dlid_path_bits = 0;
1907                 wc.port_num = 0;
1908                 /* Signal completion event if the solicited bit is set. */
1909                 rvt_cq_enter(ibcq_to_rvtcq(qp->ibqp.recv_cq), &wc,
1910                              (ohdr->bth[0] &
1911                               cpu_to_be32(IB_BTH_SOLICITED)) != 0);
1912                 break;
1913
1914         case OP(RDMA_WRITE_FIRST):
1915         case OP(RDMA_WRITE_ONLY):
1916         case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE):
1917                 if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_WRITE)))
1918                         goto nack_inv;
1919                 /* consume RWQE */
1920                 reth = &ohdr->u.rc.reth;
1921                 hdrsize += sizeof(*reth);
1922                 qp->r_len = be32_to_cpu(reth->length);
1923                 qp->r_rcv_len = 0;
1924                 qp->r_sge.sg_list = NULL;
1925                 if (qp->r_len != 0) {
1926                         u32 rkey = be32_to_cpu(reth->rkey);
1927                         u64 vaddr = be64_to_cpu(reth->vaddr);
1928                         int ok;
1929
1930                         /* Check rkey & NAK */
1931                         ok = rvt_rkey_ok(qp, &qp->r_sge.sge, qp->r_len, vaddr,
1932                                          rkey, IB_ACCESS_REMOTE_WRITE);
1933                         if (unlikely(!ok))
1934                                 goto nack_acc;
1935                         qp->r_sge.num_sge = 1;
1936                 } else {
1937                         qp->r_sge.num_sge = 0;
1938                         qp->r_sge.sge.mr = NULL;
1939                         qp->r_sge.sge.vaddr = NULL;
1940                         qp->r_sge.sge.length = 0;
1941                         qp->r_sge.sge.sge_length = 0;
1942                 }
1943                 if (opcode == OP(RDMA_WRITE_FIRST))
1944                         goto send_middle;
1945                 else if (opcode == OP(RDMA_WRITE_ONLY))
1946                         goto no_immediate_data;
1947                 ret = qib_get_rwqe(qp, 1);
1948                 if (ret < 0)
1949                         goto nack_op_err;
1950                 if (!ret)
1951                         goto rnr_nak;
1952                 wc.ex.imm_data = ohdr->u.rc.imm_data;
1953                 hdrsize += 4;
1954                 wc.wc_flags = IB_WC_WITH_IMM;
1955                 goto send_last;
1956
1957         case OP(RDMA_READ_REQUEST): {
1958                 struct rvt_ack_entry *e;
1959                 u32 len;
1960                 u8 next;
1961
1962                 if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_READ)))
1963                         goto nack_inv;
1964                 next = qp->r_head_ack_queue + 1;
1965                 /* s_ack_queue is size QIB_MAX_RDMA_ATOMIC+1 so use > not >= */
1966                 if (next > QIB_MAX_RDMA_ATOMIC)
1967                         next = 0;
1968                 spin_lock_irqsave(&qp->s_lock, flags);
1969                 if (unlikely(next == qp->s_tail_ack_queue)) {
1970                         if (!qp->s_ack_queue[next].sent)
1971                                 goto nack_inv_unlck;
1972                         qib_update_ack_queue(qp, next);
1973                 }
1974                 e = &qp->s_ack_queue[qp->r_head_ack_queue];
1975                 if (e->opcode == OP(RDMA_READ_REQUEST) && e->rdma_sge.mr) {
1976                         rvt_put_mr(e->rdma_sge.mr);
1977                         e->rdma_sge.mr = NULL;
1978                 }
1979                 reth = &ohdr->u.rc.reth;
1980                 len = be32_to_cpu(reth->length);
1981                 if (len) {
1982                         u32 rkey = be32_to_cpu(reth->rkey);
1983                         u64 vaddr = be64_to_cpu(reth->vaddr);
1984                         int ok;
1985
1986                         /* Check rkey & NAK */
1987                         ok = rvt_rkey_ok(qp, &e->rdma_sge, len, vaddr,
1988                                          rkey, IB_ACCESS_REMOTE_READ);
1989                         if (unlikely(!ok))
1990                                 goto nack_acc_unlck;
1991                         /*
1992                          * Update the next expected PSN.  We add 1 later
1993                          * below, so only add the remainder here.
1994                          */
1995                         qp->r_psn += rvt_div_mtu(qp, len - 1);
1996                 } else {
1997                         e->rdma_sge.mr = NULL;
1998                         e->rdma_sge.vaddr = NULL;
1999                         e->rdma_sge.length = 0;
2000                         e->rdma_sge.sge_length = 0;
2001                 }
2002                 e->opcode = opcode;
2003                 e->sent = 0;
2004                 e->psn = psn;
2005                 e->lpsn = qp->r_psn;
2006                 /*
2007                  * We need to increment the MSN here instead of when we
2008                  * finish sending the result since a duplicate request would
2009                  * increment it more than once.
2010                  */
2011                 qp->r_msn++;
2012                 qp->r_psn++;
2013                 qp->r_state = opcode;
2014                 qp->r_nak_state = 0;
2015                 qp->r_head_ack_queue = next;
2016
2017                 /* Schedule the send tasklet. */
2018                 qp->s_flags |= RVT_S_RESP_PENDING;
2019                 qib_schedule_send(qp);
2020
2021                 goto sunlock;
2022         }
2023
2024         case OP(COMPARE_SWAP):
2025         case OP(FETCH_ADD): {
2026                 struct ib_atomic_eth *ateth;
2027                 struct rvt_ack_entry *e;
2028                 u64 vaddr;
2029                 atomic64_t *maddr;
2030                 u64 sdata;
2031                 u32 rkey;
2032                 u8 next;
2033
2034                 if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_ATOMIC)))
2035                         goto nack_inv;
2036                 next = qp->r_head_ack_queue + 1;
2037                 if (next > QIB_MAX_RDMA_ATOMIC)
2038                         next = 0;
2039                 spin_lock_irqsave(&qp->s_lock, flags);
2040                 if (unlikely(next == qp->s_tail_ack_queue)) {
2041                         if (!qp->s_ack_queue[next].sent)
2042                                 goto nack_inv_unlck;
2043                         qib_update_ack_queue(qp, next);
2044                 }
2045                 e = &qp->s_ack_queue[qp->r_head_ack_queue];
2046                 if (e->opcode == OP(RDMA_READ_REQUEST) && e->rdma_sge.mr) {
2047                         rvt_put_mr(e->rdma_sge.mr);
2048                         e->rdma_sge.mr = NULL;
2049                 }
2050                 ateth = &ohdr->u.atomic_eth;
2051                 vaddr = get_ib_ateth_vaddr(ateth);
2052                 if (unlikely(vaddr & (sizeof(u64) - 1)))
2053                         goto nack_inv_unlck;
2054                 rkey = be32_to_cpu(ateth->rkey);
2055                 /* Check rkey & NAK */
2056                 if (unlikely(!rvt_rkey_ok(qp, &qp->r_sge.sge, sizeof(u64),
2057                                           vaddr, rkey,
2058                                           IB_ACCESS_REMOTE_ATOMIC)))
2059                         goto nack_acc_unlck;
2060                 /* Perform atomic OP and save result. */
2061                 maddr = (atomic64_t *) qp->r_sge.sge.vaddr;
2062                 sdata = get_ib_ateth_swap(ateth);
2063                 e->atomic_data = (opcode == OP(FETCH_ADD)) ?
2064                         (u64) atomic64_add_return(sdata, maddr) - sdata :
2065                         (u64) cmpxchg((u64 *) qp->r_sge.sge.vaddr,
2066                                       get_ib_ateth_compare(ateth),
2067                                       sdata);
2068                 rvt_put_mr(qp->r_sge.sge.mr);
2069                 qp->r_sge.num_sge = 0;
2070                 e->opcode = opcode;
2071                 e->sent = 0;
2072                 e->psn = psn;
2073                 e->lpsn = psn;
2074                 qp->r_msn++;
2075                 qp->r_psn++;
2076                 qp->r_state = opcode;
2077                 qp->r_nak_state = 0;
2078                 qp->r_head_ack_queue = next;
2079
2080                 /* Schedule the send tasklet. */
2081                 qp->s_flags |= RVT_S_RESP_PENDING;
2082                 qib_schedule_send(qp);
2083
2084                 goto sunlock;
2085         }
2086
2087         default:
2088                 /* NAK unknown opcodes. */
2089                 goto nack_inv;
2090         }
2091         qp->r_psn++;
2092         qp->r_state = opcode;
2093         qp->r_ack_psn = psn;
2094         qp->r_nak_state = 0;
2095         /* Send an ACK if requested or required. */
2096         if (psn & (1 << 31))
2097                 goto send_ack;
2098         return;
2099
2100 rnr_nak:
2101         qp->r_nak_state = IB_RNR_NAK | qp->r_min_rnr_timer;
2102         qp->r_ack_psn = qp->r_psn;
2103         /* Queue RNR NAK for later */
2104         if (list_empty(&qp->rspwait)) {
2105                 qp->r_flags |= RVT_R_RSP_NAK;
2106                 rvt_get_qp(qp);
2107                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
2108         }
2109         return;
2110
2111 nack_op_err:
2112         rvt_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
2113         qp->r_nak_state = IB_NAK_REMOTE_OPERATIONAL_ERROR;
2114         qp->r_ack_psn = qp->r_psn;
2115         /* Queue NAK for later */
2116         if (list_empty(&qp->rspwait)) {
2117                 qp->r_flags |= RVT_R_RSP_NAK;
2118                 rvt_get_qp(qp);
2119                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
2120         }
2121         return;
2122
2123 nack_inv_unlck:
2124         spin_unlock_irqrestore(&qp->s_lock, flags);
2125 nack_inv:
2126         rvt_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
2127         qp->r_nak_state = IB_NAK_INVALID_REQUEST;
2128         qp->r_ack_psn = qp->r_psn;
2129         /* Queue NAK for later */
2130         if (list_empty(&qp->rspwait)) {
2131                 qp->r_flags |= RVT_R_RSP_NAK;
2132                 rvt_get_qp(qp);
2133                 list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
2134         }
2135         return;
2136
2137 nack_acc_unlck:
2138         spin_unlock_irqrestore(&qp->s_lock, flags);
2139 nack_acc:
2140         rvt_rc_error(qp, IB_WC_LOC_PROT_ERR);
2141         qp->r_nak_state = IB_NAK_REMOTE_ACCESS_ERROR;
2142         qp->r_ack_psn = qp->r_psn;
2143 send_ack:
2144         qib_send_rc_ack(qp);
2145         return;
2146
2147 sunlock:
2148         spin_unlock_irqrestore(&qp->s_lock, flags);
2149 }