drivers/infiniband/hw/qib/qib_uc.c

   1 /*
   2  * Copyright (c) 2006, 2007, 2008, 2009, 2010 QLogic Corporation.
   3  * All rights reserved.
   4  * Copyright (c) 2005, 2006 PathScale, Inc. All rights reserved.
   5  *
   6  * This software is available to you under a choice of one of two
   7  * licenses.  You may choose to be licensed under the terms of the GNU
   8  * General Public License (GPL) Version 2, available from the file
   9  * COPYING in the main directory of this source tree, or the
  10  * OpenIB.org BSD license below:
  11  *
  12  *     Redistribution and use in source and binary forms, with or
  13  *     without modification, are permitted provided that the following
  14  *     conditions are met:
  15  *
  16  *      - Redistributions of source code must retain the above
  17  *        copyright notice, this list of conditions and the following
  18  *        disclaimer.
  19  *
  20  *      - Redistributions in binary form must reproduce the above
  21  *        copyright notice, this list of conditions and the following
  22  *        disclaimer in the documentation and/or other materials
  23  *        provided with the distribution.
  24  *
  25  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  26  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  27  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  28  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  29  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  30  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  31  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  32  * SOFTWARE.
  33  */
  34
  35 #include "qib.h"
  36
  37 /* cut down ridiculously long IB macro names */
  38 #define OP(x) IB_OPCODE_UC_##x
  39
  40 /**
  41  * qib_make_uc_req - construct a request packet (SEND, RDMA write)
  42  * @qp: a pointer to the QP
  43  *
  44  * Return 1 if constructed; otherwise, return 0.
  45  */
  46 int qib_make_uc_req(struct qib_qp *qp)
  47 {
  48         struct qib_other_headers *ohdr;
  49         struct qib_swqe *wqe;
  50         unsigned long flags;
  51         u32 hwords;
  52         u32 bth0;
  53         u32 len;
  54         u32 pmtu = qp->pmtu;
  55         int ret = 0;
  56
  57         spin_lock_irqsave(&qp->s_lock, flags);
  58
  59         if (!(ib_qib_state_ops[qp->state] & QIB_PROCESS_SEND_OK)) {
  60                 if (!(ib_qib_state_ops[qp->state] & QIB_FLUSH_SEND))
  61                         goto bail;
  62                 /* We are in the error state, flush the work request. */
  63                 if (qp->s_last == qp->s_head)
  64                         goto bail;
  65                 /* If DMAs are in progress, we can't flush immediately. */
  66                 if (atomic_read(&qp->s_dma_busy)) {
  67                         qp->s_flags |= QIB_S_WAIT_DMA;
  68                         goto bail;
  69                 }
  70                 wqe = get_swqe_ptr(qp, qp->s_last);
  71                 qib_send_complete(qp, wqe, IB_WC_WR_FLUSH_ERR);
  72                 goto done;
  73         }
  74
  75         ohdr = &qp->s_hdr->u.oth;
  76         if (qp->remote_ah_attr.ah_flags & IB_AH_GRH)
  77                 ohdr = &qp->s_hdr->u.l.oth;
  78
  79         /* header size in 32-bit words LRH+BTH = (8+12)/4. */
  80         hwords = 5;
  81         bth0 = 0;
  82
  83         /* Get the next send request. */
  84         wqe = get_swqe_ptr(qp, qp->s_cur);
  85         qp->s_wqe = NULL;
  86         switch (qp->s_state) {
  87         default:
  88                 if (!(ib_qib_state_ops[qp->state] &
  89                     QIB_PROCESS_NEXT_SEND_OK))
  90                         goto bail;
  91                 /* Check if send work queue is empty. */
  92                 if (qp->s_cur == qp->s_head)
  93                         goto bail;
  94                 /*
  95                  * Start a new request.
  96                  */
  97                 wqe->psn = qp->s_next_psn;
  98                 qp->s_psn = qp->s_next_psn;
  99                 qp->s_sge.sge = wqe->sg_list[0];
 100                 qp->s_sge.sg_list = wqe->sg_list + 1;
 101                 qp->s_sge.num_sge = wqe->wr.num_sge;
 102                 qp->s_sge.total_len = wqe->length;
 103                 len = wqe->length;
 104                 qp->s_len = len;
 105                 switch (wqe->wr.opcode) {
 106                 case IB_WR_SEND:
 107                 case IB_WR_SEND_WITH_IMM:
 108                         if (len > pmtu) {
 109                                 qp->s_state = OP(SEND_FIRST);
 110                                 len = pmtu;
 111                                 break;
 112                         }
 113                         if (wqe->wr.opcode == IB_WR_SEND)
 114                                 qp->s_state = OP(SEND_ONLY);
 115                         else {
 116                                 qp->s_state =
 117                                         OP(SEND_ONLY_WITH_IMMEDIATE);
 118                                 /* Immediate data comes after the BTH */
 119                                 ohdr->u.imm_data = wqe->wr.ex.imm_data;
 120                                 hwords += 1;
 121                         }
 122                         if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 123                                 bth0 |= IB_BTH_SOLICITED;
 124                         qp->s_wqe = wqe;
 125                         if (++qp->s_cur >= qp->s_size)
 126                                 qp->s_cur = 0;
 127                         break;
 128
 129                 case IB_WR_RDMA_WRITE:
 130                 case IB_WR_RDMA_WRITE_WITH_IMM:
 131                         ohdr->u.rc.reth.vaddr =
 132                                 cpu_to_be64(wqe->wr.wr.rdma.remote_addr);
 133                         ohdr->u.rc.reth.rkey =
 134                                 cpu_to_be32(wqe->wr.wr.rdma.rkey);
 135                         ohdr->u.rc.reth.length = cpu_to_be32(len);
 136                         hwords += sizeof(struct ib_reth) / 4;
 137                         if (len > pmtu) {
 138                                 qp->s_state = OP(RDMA_WRITE_FIRST);
 139                                 len = pmtu;
 140                                 break;
 141                         }
 142                         if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
 143                                 qp->s_state = OP(RDMA_WRITE_ONLY);
 144                         else {
 145                                 qp->s_state =
 146                                         OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE);
 147                                 /* Immediate data comes after the RETH */
 148                                 ohdr->u.rc.imm_data = wqe->wr.ex.imm_data;
 149                                 hwords += 1;
 150                                 if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 151                                         bth0 |= IB_BTH_SOLICITED;
 152                         }
 153                         qp->s_wqe = wqe;
 154                         if (++qp->s_cur >= qp->s_size)
 155                                 qp->s_cur = 0;
 156                         break;
 157
 158                 default:
 159                         goto bail;
 160                 }
 161                 break;
 162
 163         case OP(SEND_FIRST):
 164                 qp->s_state = OP(SEND_MIDDLE);
 165                 /* FALLTHROUGH */
 166         case OP(SEND_MIDDLE):
 167                 len = qp->s_len;
 168                 if (len > pmtu) {
 169                         len = pmtu;
 170                         break;
 171                 }
 172                 if (wqe->wr.opcode == IB_WR_SEND)
 173                         qp->s_state = OP(SEND_LAST);
 174                 else {
 175                         qp->s_state = OP(SEND_LAST_WITH_IMMEDIATE);
 176                         /* Immediate data comes after the BTH */
 177                         ohdr->u.imm_data = wqe->wr.ex.imm_data;
 178                         hwords += 1;
 179                 }
 180                 if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 181                         bth0 |= IB_BTH_SOLICITED;
 182                 qp->s_wqe = wqe;
 183                 if (++qp->s_cur >= qp->s_size)
 184                         qp->s_cur = 0;
 185                 break;
 186
 187         case OP(RDMA_WRITE_FIRST):
 188                 qp->s_state = OP(RDMA_WRITE_MIDDLE);
 189                 /* FALLTHROUGH */
 190         case OP(RDMA_WRITE_MIDDLE):
 191                 len = qp->s_len;
 192                 if (len > pmtu) {
 193                         len = pmtu;
 194                         break;
 195                 }
 196                 if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
 197                         qp->s_state = OP(RDMA_WRITE_LAST);
 198                 else {
 199                         qp->s_state =
 200                                 OP(RDMA_WRITE_LAST_WITH_IMMEDIATE);
 201                         /* Immediate data comes after the BTH */
 202                         ohdr->u.imm_data = wqe->wr.ex.imm_data;
 203                         hwords += 1;
 204                         if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 205                                 bth0 |= IB_BTH_SOLICITED;
 206                 }
 207                 qp->s_wqe = wqe;
 208                 if (++qp->s_cur >= qp->s_size)
 209                         qp->s_cur = 0;
 210                 break;
 211         }
 212         qp->s_len -= len;
 213         qp->s_hdrwords = hwords;
 214         qp->s_cur_sge = &qp->s_sge;
 215         qp->s_cur_size = len;
 216         qib_make_ruc_header(qp, ohdr, bth0 | (qp->s_state << 24),
 217                             qp->s_next_psn++ & QIB_PSN_MASK);
 218 done:
 219         ret = 1;
 220         goto unlock;
 221
 222 bail:
 223         qp->s_flags &= ~QIB_S_BUSY;
 224 unlock:
 225         spin_unlock_irqrestore(&qp->s_lock, flags);
 226         return ret;
 227 }
 228
 229 /**
 230  * qib_uc_rcv - handle an incoming UC packet
 231  * @ibp: the port the packet came in on
 232  * @hdr: the header of the packet
 233  * @has_grh: true if the packet has a GRH
 234  * @data: the packet data
 235  * @tlen: the length of the packet
 236  * @qp: the QP for this packet.
 237  *
 238  * This is called from qib_qp_rcv() to process an incoming UC packet
 239  * for the given QP.
 240  * Called at interrupt level.
 241  */
 242 void qib_uc_rcv(struct qib_ibport *ibp, struct qib_ib_header *hdr,
 243                 int has_grh, void *data, u32 tlen, struct qib_qp *qp)
 244 {
 245         struct qib_other_headers *ohdr;
 246         u32 opcode;
 247         u32 hdrsize;
 248         u32 psn;
 249         u32 pad;
 250         struct ib_wc wc;
 251         u32 pmtu = qp->pmtu;
 252         struct ib_reth *reth;
 253         int ret;
 254
 255         /* Check for GRH */
 256         if (!has_grh) {
 257                 ohdr = &hdr->u.oth;
 258                 hdrsize = 8 + 12;       /* LRH + BTH */
 259         } else {
 260                 ohdr = &hdr->u.l.oth;
 261                 hdrsize = 8 + 40 + 12;  /* LRH + GRH + BTH */
 262         }
 263
 264         opcode = be32_to_cpu(ohdr->bth[0]);
 265         if (qib_ruc_check_hdr(ibp, hdr, has_grh, qp, opcode))
 266                 return;
 267
 268         psn = be32_to_cpu(ohdr->bth[2]);
 269         opcode >>= 24;
 270
 271         /* Compare the PSN verses the expected PSN. */
 272         if (unlikely(qib_cmp24(psn, qp->r_psn) != 0)) {
 273                 /*
 274                  * Handle a sequence error.
 275                  * Silently drop any current message.
 276                  */
 277                 qp->r_psn = psn;
 278 inv:
 279                 if (qp->r_state == OP(SEND_FIRST) ||
 280                     qp->r_state == OP(SEND_MIDDLE)) {
 281                         set_bit(QIB_R_REWIND_SGE, &qp->r_aflags);
 282                         qp->r_sge.num_sge = 0;
 283                 } else
 284                         while (qp->r_sge.num_sge) {
 285                                 atomic_dec(&qp->r_sge.sge.mr->refcount);
 286                                 if (--qp->r_sge.num_sge)
 287                                         qp->r_sge.sge = *qp->r_sge.sg_list++;
 288                         }
 289                 qp->r_state = OP(SEND_LAST);
 290                 switch (opcode) {
 291                 case OP(SEND_FIRST):
 292                 case OP(SEND_ONLY):
 293                 case OP(SEND_ONLY_WITH_IMMEDIATE):
 294                         goto send_first;
 295
 296                 case OP(RDMA_WRITE_FIRST):
 297                 case OP(RDMA_WRITE_ONLY):
 298                 case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE):
 299                         goto rdma_first;
 300
 301                 default:
 302                         goto drop;
 303                 }
 304         }
 305
 306         /* Check for opcode sequence errors. */
 307         switch (qp->r_state) {
 308         case OP(SEND_FIRST):
 309         case OP(SEND_MIDDLE):
 310                 if (opcode == OP(SEND_MIDDLE) ||
 311                     opcode == OP(SEND_LAST) ||
 312                     opcode == OP(SEND_LAST_WITH_IMMEDIATE))
 313                         break;
 314                 goto inv;
 315
 316         case OP(RDMA_WRITE_FIRST):
 317         case OP(RDMA_WRITE_MIDDLE):
 318                 if (opcode == OP(RDMA_WRITE_MIDDLE) ||
 319                     opcode == OP(RDMA_WRITE_LAST) ||
 320                     opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
 321                         break;
 322                 goto inv;
 323
 324         default:
 325                 if (opcode == OP(SEND_FIRST) ||
 326                     opcode == OP(SEND_ONLY) ||
 327                     opcode == OP(SEND_ONLY_WITH_IMMEDIATE) ||
 328                     opcode == OP(RDMA_WRITE_FIRST) ||
 329                     opcode == OP(RDMA_WRITE_ONLY) ||
 330                     opcode == OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE))
 331                         break;
 332                 goto inv;
 333         }
 334
 335         if (qp->state == IB_QPS_RTR && !(qp->r_flags & QIB_R_COMM_EST)) {
 336                 qp->r_flags |= QIB_R_COMM_EST;
 337                 if (qp->ibqp.event_handler) {
 338                         struct ib_event ev;
 339
 340                         ev.device = qp->ibqp.device;
 341                         ev.element.qp = &qp->ibqp;
 342                         ev.event = IB_EVENT_COMM_EST;
 343                         qp->ibqp.event_handler(&ev, qp->ibqp.qp_context);
 344                 }
 345         }
 346
 347         /* OK, process the packet. */
 348         switch (opcode) {
 349         case OP(SEND_FIRST):
 350         case OP(SEND_ONLY):
 351         case OP(SEND_ONLY_WITH_IMMEDIATE):
 352 send_first:
 353                 if (test_and_clear_bit(QIB_R_REWIND_SGE, &qp->r_aflags))
 354                         qp->r_sge = qp->s_rdma_read_sge;
 355                 else {
 356                         ret = qib_get_rwqe(qp, 0);
 357                         if (ret < 0)
 358                                 goto op_err;
 359                         if (!ret)
 360                                 goto drop;
 361                         /*
 362                          * qp->s_rdma_read_sge will be the owner
 363                          * of the mr references.
 364                          */
 365                         qp->s_rdma_read_sge = qp->r_sge;
 366                 }
 367                 qp->r_rcv_len = 0;
 368                 if (opcode == OP(SEND_ONLY))
 369                         goto no_immediate_data;
 370                 else if (opcode == OP(SEND_ONLY_WITH_IMMEDIATE))
 371                         goto send_last_imm;
 372                 /* FALLTHROUGH */
 373         case OP(SEND_MIDDLE):
 374                 /* Check for invalid length PMTU or posted rwqe len. */
 375                 if (unlikely(tlen != (hdrsize + pmtu + 4)))
 376                         goto rewind;
 377                 qp->r_rcv_len += pmtu;
 378                 if (unlikely(qp->r_rcv_len > qp->r_len))
 379                         goto rewind;
 380                 qib_copy_sge(&qp->r_sge, data, pmtu, 0);
 381                 break;
 382
 383         case OP(SEND_LAST_WITH_IMMEDIATE):
 384 send_last_imm:
 385                 wc.ex.imm_data = ohdr->u.imm_data;
 386                 hdrsize += 4;
 387                 wc.wc_flags = IB_WC_WITH_IMM;
 388                 goto send_last;
 389         case OP(SEND_LAST):
 390 no_immediate_data:
 391                 wc.ex.imm_data = 0;
 392                 wc.wc_flags = 0;
 393 send_last:
 394                 /* Get the number of bytes the message was padded by. */
 395                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
 396                 /* Check for invalid length. */
 397                 /* XXX LAST len should be >= 1 */
 398                 if (unlikely(tlen < (hdrsize + pad + 4)))
 399                         goto rewind;
 400                 /* Don't count the CRC. */
 401                 tlen -= (hdrsize + pad + 4);
 402                 wc.byte_len = tlen + qp->r_rcv_len;
 403                 if (unlikely(wc.byte_len > qp->r_len))
 404                         goto rewind;
 405                 wc.opcode = IB_WC_RECV;
 406                 qib_copy_sge(&qp->r_sge, data, tlen, 0);
 407                 while (qp->s_rdma_read_sge.num_sge) {
 408                         atomic_dec(&qp->s_rdma_read_sge.sge.mr->refcount);
 409                         if (--qp->s_rdma_read_sge.num_sge)
 410                                 qp->s_rdma_read_sge.sge =
 411                                         *qp->s_rdma_read_sge.sg_list++;
 412                 }
 413 last_imm:
 414                 wc.wr_id = qp->r_wr_id;
 415                 wc.status = IB_WC_SUCCESS;
 416                 wc.qp = &qp->ibqp;
 417                 wc.src_qp = qp->remote_qpn;
 418                 wc.slid = qp->remote_ah_attr.dlid;
 419                 wc.sl = qp->remote_ah_attr.sl;
 420                 /* zero fields that are N/A */
 421                 wc.vendor_err = 0;
 422                 wc.pkey_index = 0;
 423                 wc.dlid_path_bits = 0;
 424                 wc.port_num = 0;
 425                 /* Signal completion event if the solicited bit is set. */
 426                 qib_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
 427                              (ohdr->bth[0] &
 428                                 cpu_to_be32(IB_BTH_SOLICITED)) != 0);
 429                 break;
 430
 431         case OP(RDMA_WRITE_FIRST):
 432         case OP(RDMA_WRITE_ONLY):
 433         case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE): /* consume RWQE */
 434 rdma_first:
 435                 if (unlikely(!(qp->qp_access_flags &
 436                                IB_ACCESS_REMOTE_WRITE))) {
 437                         goto drop;
 438                 }
 439                 reth = &ohdr->u.rc.reth;
 440                 hdrsize += sizeof(*reth);
 441                 qp->r_len = be32_to_cpu(reth->length);
 442                 qp->r_rcv_len = 0;
 443                 qp->r_sge.sg_list = NULL;
 444                 if (qp->r_len != 0) {
 445                         u32 rkey = be32_to_cpu(reth->rkey);
 446                         u64 vaddr = be64_to_cpu(reth->vaddr);
 447                         int ok;
 448
 449                         /* Check rkey */
 450                         ok = qib_rkey_ok(qp, &qp->r_sge.sge, qp->r_len,
 451                                          vaddr, rkey, IB_ACCESS_REMOTE_WRITE);
 452                         if (unlikely(!ok))
 453                                 goto drop;
 454                         qp->r_sge.num_sge = 1;
 455                 } else {
 456                         qp->r_sge.num_sge = 0;
 457                         qp->r_sge.sge.mr = NULL;
 458                         qp->r_sge.sge.vaddr = NULL;
 459                         qp->r_sge.sge.length = 0;
 460                         qp->r_sge.sge.sge_length = 0;
 461                 }
 462                 if (opcode == OP(RDMA_WRITE_ONLY))
 463                         goto rdma_last;
 464                 else if (opcode == OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE)) {
 465                         wc.ex.imm_data = ohdr->u.rc.imm_data;
 466                         goto rdma_last_imm;
 467                 }
 468                 /* FALLTHROUGH */
 469         case OP(RDMA_WRITE_MIDDLE):
 470                 /* Check for invalid length PMTU or posted rwqe len. */
 471                 if (unlikely(tlen != (hdrsize + pmtu + 4)))
 472                         goto drop;
 473                 qp->r_rcv_len += pmtu;
 474                 if (unlikely(qp->r_rcv_len > qp->r_len))
 475                         goto drop;
 476                 qib_copy_sge(&qp->r_sge, data, pmtu, 1);
 477                 break;
 478
 479         case OP(RDMA_WRITE_LAST_WITH_IMMEDIATE):
 480                 wc.ex.imm_data = ohdr->u.imm_data;
 481 rdma_last_imm:
 482                 hdrsize += 4;
 483                 wc.wc_flags = IB_WC_WITH_IMM;
 484
 485                 /* Get the number of bytes the message was padded by. */
 486                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
 487                 /* Check for invalid length. */
 488                 /* XXX LAST len should be >= 1 */
 489                 if (unlikely(tlen < (hdrsize + pad + 4)))
 490                         goto drop;
 491                 /* Don't count the CRC. */
 492                 tlen -= (hdrsize + pad + 4);
 493                 if (unlikely(tlen + qp->r_rcv_len != qp->r_len))
 494                         goto drop;
 495                 if (test_and_clear_bit(QIB_R_REWIND_SGE, &qp->r_aflags))
 496                         while (qp->s_rdma_read_sge.num_sge) {
 497                                 atomic_dec(&qp->s_rdma_read_sge.sge.mr->
 498                                            refcount);
 499                                 if (--qp->s_rdma_read_sge.num_sge)
 500                                         qp->s_rdma_read_sge.sge =
 501                                                 *qp->s_rdma_read_sge.sg_list++;
 502                         }
 503                 else {
 504                         ret = qib_get_rwqe(qp, 1);
 505                         if (ret < 0)
 506                                 goto op_err;
 507                         if (!ret)
 508                                 goto drop;
 509                 }
 510                 wc.byte_len = qp->r_len;
 511                 wc.opcode = IB_WC_RECV_RDMA_WITH_IMM;
 512                 qib_copy_sge(&qp->r_sge, data, tlen, 1);
 513                 while (qp->r_sge.num_sge) {
 514                         atomic_dec(&qp->r_sge.sge.mr->refcount);
 515                         if (--qp->r_sge.num_sge)
 516                                 qp->r_sge.sge = *qp->r_sge.sg_list++;
 517                 }
 518                 goto last_imm;
 519
 520         case OP(RDMA_WRITE_LAST):
 521 rdma_last:
 522                 /* Get the number of bytes the message was padded by. */
 523                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
 524                 /* Check for invalid length. */
 525                 /* XXX LAST len should be >= 1 */
 526                 if (unlikely(tlen < (hdrsize + pad + 4)))
 527                         goto drop;
 528                 /* Don't count the CRC. */
 529                 tlen -= (hdrsize + pad + 4);
 530                 if (unlikely(tlen + qp->r_rcv_len != qp->r_len))
 531                         goto drop;
 532                 qib_copy_sge(&qp->r_sge, data, tlen, 1);
 533                 while (qp->r_sge.num_sge) {
 534                         atomic_dec(&qp->r_sge.sge.mr->refcount);
 535                         if (--qp->r_sge.num_sge)
 536                                 qp->r_sge.sge = *qp->r_sge.sg_list++;
 537                 }
 538                 break;
 539
 540         default:
 541                 /* Drop packet for unknown opcodes. */
 542                 goto drop;
 543         }
 544         qp->r_psn++;
 545         qp->r_state = opcode;
 546         return;
 547
 548 rewind:
 549         set_bit(QIB_R_REWIND_SGE, &qp->r_aflags);
 550         qp->r_sge.num_sge = 0;
 551 drop:
 552         ibp->n_pkt_drops++;
 553         return;
 554
 555 op_err:
 556         qib_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
 557         return;
 558
 559 }