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