drivers/infiniband/hw/hfi1/uc.c

   1 /*
   2  * Copyright(c) 2015 - 2018 Intel Corporation.
   3  *
   4  * This file is provided under a dual BSD/GPLv2 license.  When using or
   5  * redistributing this file, you may do so under either license.
   6  *
   7  * GPL LICENSE SUMMARY
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of version 2 of the GNU General Public License as
  11  * published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * General Public License for more details.
  17  *
  18  * BSD LICENSE
  19  *
  20  * Redistribution and use in source and binary forms, with or without
  21  * modification, are permitted provided that the following conditions
  22  * are met:
  23  *
  24  *  - Redistributions of source code must retain the above copyright
  25  *    notice, this list of conditions and the following disclaimer.
  26  *  - Redistributions in binary form must reproduce the above copyright
  27  *    notice, this list of conditions and the following disclaimer in
  28  *    the documentation and/or other materials provided with the
  29  *    distribution.
  30  *  - Neither the name of Intel Corporation nor the names of its
  31  *    contributors may be used to endorse or promote products derived
  32  *    from this software without specific prior written permission.
  33  *
  34  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  35  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  36  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  37  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  38  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  39  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  40  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  41  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  42  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  43  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  44  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  45  *
  46  */
  47
  48 #include "hfi.h"
  49 #include "verbs_txreq.h"
  50 #include "qp.h"
  51
  52 /* cut down ridiculously long IB macro names */
  53 #define OP(x) UC_OP(x)
  54
  55 /**
  56  * hfi1_make_uc_req - construct a request packet (SEND, RDMA write)
  57  * @qp: a pointer to the QP
  58  *
  59  * Assume s_lock is held.
  60  *
  61  * Return 1 if constructed; otherwise, return 0.
  62  */
  63 int hfi1_make_uc_req(struct rvt_qp *qp, struct hfi1_pkt_state *ps)
  64 {
  65         struct hfi1_qp_priv *priv = qp->priv;
  66         struct ib_other_headers *ohdr;
  67         struct rvt_swqe *wqe;
  68         u32 hwords = 5;
  69         u32 bth0 = 0;
  70         u32 len;
  71         u32 pmtu = qp->pmtu;
  72         int middle = 0;
  73
  74         ps->s_txreq = get_txreq(ps->dev, qp);
  75         if (!ps->s_txreq)
  76                 goto bail_no_tx;
  77
  78         if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_SEND_OK)) {
  79                 if (!(ib_rvt_state_ops[qp->state] & RVT_FLUSH_SEND))
  80                         goto bail;
  81                 /* We are in the error state, flush the work request. */
  82                 smp_read_barrier_depends(); /* see post_one_send() */
  83                 if (qp->s_last == ACCESS_ONCE(qp->s_head))
  84                         goto bail;
  85                 /* If DMAs are in progress, we can't flush immediately. */
  86                 if (iowait_sdma_pending(&priv->s_iowait)) {
  87                         qp->s_flags |= RVT_S_WAIT_DMA;
  88                         goto bail;
  89                 }
  90                 clear_ahg(qp);
  91                 wqe = rvt_get_swqe_ptr(qp, qp->s_last);
  92                 hfi1_send_complete(qp, wqe, IB_WC_WR_FLUSH_ERR);
  93                 goto done_free_tx;
  94         }
  95
  96         ohdr = &ps->s_txreq->phdr.hdr.u.oth;
  97         if (qp->remote_ah_attr.ah_flags & IB_AH_GRH)
  98                 ohdr = &ps->s_txreq->phdr.hdr.u.l.oth;
  99
 100         /* Get the next send request. */
 101         wqe = rvt_get_swqe_ptr(qp, qp->s_cur);
 102         qp->s_wqe = NULL;
 103         switch (qp->s_state) {
 104         default:
 105                 if (!(ib_rvt_state_ops[qp->state] &
 106                     RVT_PROCESS_NEXT_SEND_OK))
 107                         goto bail;
 108                 /* Check if send work queue is empty. */
 109                 smp_read_barrier_depends(); /* see post_one_send() */
 110                 if (qp->s_cur == ACCESS_ONCE(qp->s_head)) {
 111                         clear_ahg(qp);
 112                         goto bail;
 113                 }
 114                 /*
 115                  * Local operations are processed immediately
 116                  * after all prior requests have completed.
 117                  */
 118                 if (wqe->wr.opcode == IB_WR_REG_MR ||
 119                     wqe->wr.opcode == IB_WR_LOCAL_INV) {
 120                         int local_ops = 0;
 121                         int err = 0;
 122
 123                         if (qp->s_last != qp->s_cur)
 124                                 goto bail;
 125                         if (++qp->s_cur == qp->s_size)
 126                                 qp->s_cur = 0;
 127                         if (!(wqe->wr.send_flags & RVT_SEND_COMPLETION_ONLY)) {
 128                                 err = rvt_invalidate_rkey(
 129                                         qp, wqe->wr.ex.invalidate_rkey);
 130                                 local_ops = 1;
 131                         }
 132                         hfi1_send_complete(qp, wqe, err ? IB_WC_LOC_PROT_ERR
 133                                                         : IB_WC_SUCCESS);
 134                         if (local_ops)
 135                                 atomic_dec(&qp->local_ops_pending);
 136                         qp->s_hdrwords = 0;
 137                         goto done_free_tx;
 138                 }
 139                 /*
 140                  * Start a new request.
 141                  */
 142                 qp->s_psn = wqe->psn;
 143                 qp->s_sge.sge = wqe->sg_list[0];
 144                 qp->s_sge.sg_list = wqe->sg_list + 1;
 145                 qp->s_sge.num_sge = wqe->wr.num_sge;
 146                 qp->s_sge.total_len = wqe->length;
 147                 len = wqe->length;
 148                 qp->s_len = len;
 149                 switch (wqe->wr.opcode) {
 150                 case IB_WR_SEND:
 151                 case IB_WR_SEND_WITH_IMM:
 152                         if (len > pmtu) {
 153                                 qp->s_state = OP(SEND_FIRST);
 154                                 len = pmtu;
 155                                 break;
 156                         }
 157                         if (wqe->wr.opcode == IB_WR_SEND) {
 158                                 qp->s_state = OP(SEND_ONLY);
 159                         } else {
 160                                 qp->s_state =
 161                                         OP(SEND_ONLY_WITH_IMMEDIATE);
 162                                 /* Immediate data comes after the BTH */
 163                                 ohdr->u.imm_data = wqe->wr.ex.imm_data;
 164                                 hwords += 1;
 165                         }
 166                         if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 167                                 bth0 |= IB_BTH_SOLICITED;
 168                         qp->s_wqe = wqe;
 169                         if (++qp->s_cur >= qp->s_size)
 170                                 qp->s_cur = 0;
 171                         break;
 172
 173                 case IB_WR_RDMA_WRITE:
 174                 case IB_WR_RDMA_WRITE_WITH_IMM:
 175                         ohdr->u.rc.reth.vaddr =
 176                                 cpu_to_be64(wqe->rdma_wr.remote_addr);
 177                         ohdr->u.rc.reth.rkey =
 178                                 cpu_to_be32(wqe->rdma_wr.rkey);
 179                         ohdr->u.rc.reth.length = cpu_to_be32(len);
 180                         hwords += sizeof(struct ib_reth) / 4;
 181                         if (len > pmtu) {
 182                                 qp->s_state = OP(RDMA_WRITE_FIRST);
 183                                 len = pmtu;
 184                                 break;
 185                         }
 186                         if (wqe->wr.opcode == IB_WR_RDMA_WRITE) {
 187                                 qp->s_state = OP(RDMA_WRITE_ONLY);
 188                         } else {
 189                                 qp->s_state =
 190                                         OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE);
 191                                 /* Immediate data comes after the RETH */
 192                                 ohdr->u.rc.imm_data = wqe->wr.ex.imm_data;
 193                                 hwords += 1;
 194                                 if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 195                                         bth0 |= IB_BTH_SOLICITED;
 196                         }
 197                         qp->s_wqe = wqe;
 198                         if (++qp->s_cur >= qp->s_size)
 199                                 qp->s_cur = 0;
 200                         break;
 201
 202                 default:
 203                         goto bail;
 204                 }
 205                 break;
 206
 207         case OP(SEND_FIRST):
 208                 qp->s_state = OP(SEND_MIDDLE);
 209                 /* FALLTHROUGH */
 210         case OP(SEND_MIDDLE):
 211                 len = qp->s_len;
 212                 if (len > pmtu) {
 213                         len = pmtu;
 214                         middle = HFI1_CAP_IS_KSET(SDMA_AHG);
 215                         break;
 216                 }
 217                 if (wqe->wr.opcode == IB_WR_SEND) {
 218                         qp->s_state = OP(SEND_LAST);
 219                 } else {
 220                         qp->s_state = OP(SEND_LAST_WITH_IMMEDIATE);
 221                         /* Immediate data comes after the BTH */
 222                         ohdr->u.imm_data = wqe->wr.ex.imm_data;
 223                         hwords += 1;
 224                 }
 225                 if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 226                         bth0 |= IB_BTH_SOLICITED;
 227                 qp->s_wqe = wqe;
 228                 if (++qp->s_cur >= qp->s_size)
 229                         qp->s_cur = 0;
 230                 break;
 231
 232         case OP(RDMA_WRITE_FIRST):
 233                 qp->s_state = OP(RDMA_WRITE_MIDDLE);
 234                 /* FALLTHROUGH */
 235         case OP(RDMA_WRITE_MIDDLE):
 236                 len = qp->s_len;
 237                 if (len > pmtu) {
 238                         len = pmtu;
 239                         middle = HFI1_CAP_IS_KSET(SDMA_AHG);
 240                         break;
 241                 }
 242                 if (wqe->wr.opcode == IB_WR_RDMA_WRITE) {
 243                         qp->s_state = OP(RDMA_WRITE_LAST);
 244                 } else {
 245                         qp->s_state =
 246                                 OP(RDMA_WRITE_LAST_WITH_IMMEDIATE);
 247                         /* Immediate data comes after the BTH */
 248                         ohdr->u.imm_data = wqe->wr.ex.imm_data;
 249                         hwords += 1;
 250                         if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 251                                 bth0 |= IB_BTH_SOLICITED;
 252                 }
 253                 qp->s_wqe = wqe;
 254                 if (++qp->s_cur >= qp->s_size)
 255                         qp->s_cur = 0;
 256                 break;
 257         }
 258         qp->s_len -= len;
 259         qp->s_hdrwords = hwords;
 260         ps->s_txreq->sde = priv->s_sde;
 261         qp->s_cur_sge = &qp->s_sge;
 262         qp->s_cur_size = len;
 263         hfi1_make_ruc_header(qp, ohdr, bth0 | (qp->s_state << 24),
 264                              mask_psn(qp->s_psn++), middle, ps);
 265         /* pbc */
 266         ps->s_txreq->hdr_dwords = qp->s_hdrwords + 2;
 267         return 1;
 268
 269 done_free_tx:
 270         hfi1_put_txreq(ps->s_txreq);
 271         ps->s_txreq = NULL;
 272         return 1;
 273
 274 bail:
 275         hfi1_put_txreq(ps->s_txreq);
 276
 277 bail_no_tx:
 278         ps->s_txreq = NULL;
 279         qp->s_flags &= ~RVT_S_BUSY;
 280         qp->s_hdrwords = 0;
 281         return 0;
 282 }
 283
 284 /**
 285  * hfi1_uc_rcv - handle an incoming UC packet
 286  * @ibp: the port the packet came in on
 287  * @hdr: the header of the packet
 288  * @rcv_flags: flags relevant to rcv processing
 289  * @data: the packet data
 290  * @tlen: the length of the packet
 291  * @qp: the QP for this packet.
 292  *
 293  * This is called from qp_rcv() to process an incoming UC packet
 294  * for the given QP.
 295  * Called at interrupt level.
 296  */
 297 void hfi1_uc_rcv(struct hfi1_packet *packet)
 298 {
 299         struct hfi1_ibport *ibp = &packet->rcd->ppd->ibport_data;
 300         struct ib_header *hdr = packet->hdr;
 301         u32 rcv_flags = packet->rcv_flags;
 302         void *data = packet->ebuf;
 303         u32 tlen = packet->tlen;
 304         struct rvt_qp *qp = packet->qp;
 305         struct ib_other_headers *ohdr = packet->ohdr;
 306         u32 bth0, opcode;
 307         u32 hdrsize = packet->hlen;
 308         u32 psn;
 309         u32 pad;
 310         struct ib_wc wc;
 311         u32 pmtu = qp->pmtu;
 312         struct ib_reth *reth;
 313         int has_grh = rcv_flags & HFI1_HAS_GRH;
 314         int ret;
 315
 316         bth0 = be32_to_cpu(ohdr->bth[0]);
 317         if (hfi1_ruc_check_hdr(ibp, hdr, has_grh, qp, bth0))
 318                 return;
 319
 320         process_ecn(qp, packet, true);
 321
 322         psn = be32_to_cpu(ohdr->bth[2]);
 323         opcode = (bth0 >> 24) & 0xff;
 324
 325         /* Compare the PSN verses the expected PSN. */
 326         if (unlikely(cmp_psn(psn, qp->r_psn) != 0)) {
 327                 /*
 328                  * Handle a sequence error.
 329                  * Silently drop any current message.
 330                  */
 331                 qp->r_psn = psn;
 332 inv:
 333                 if (qp->r_state == OP(SEND_FIRST) ||
 334                     qp->r_state == OP(SEND_MIDDLE)) {
 335                         set_bit(RVT_R_REWIND_SGE, &qp->r_aflags);
 336                         qp->r_sge.num_sge = 0;
 337                 } else {
 338                         rvt_put_ss(&qp->r_sge);
 339                 }
 340                 qp->r_state = OP(SEND_LAST);
 341                 switch (opcode) {
 342                 case OP(SEND_FIRST):
 343                 case OP(SEND_ONLY):
 344                 case OP(SEND_ONLY_WITH_IMMEDIATE):
 345                         goto send_first;
 346
 347                 case OP(RDMA_WRITE_FIRST):
 348                 case OP(RDMA_WRITE_ONLY):
 349                 case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE):
 350                         goto rdma_first;
 351
 352                 default:
 353                         goto drop;
 354                 }
 355         }
 356
 357         /* Check for opcode sequence errors. */
 358         switch (qp->r_state) {
 359         case OP(SEND_FIRST):
 360         case OP(SEND_MIDDLE):
 361                 if (opcode == OP(SEND_MIDDLE) ||
 362                     opcode == OP(SEND_LAST) ||
 363                     opcode == OP(SEND_LAST_WITH_IMMEDIATE))
 364                         break;
 365                 goto inv;
 366
 367         case OP(RDMA_WRITE_FIRST):
 368         case OP(RDMA_WRITE_MIDDLE):
 369                 if (opcode == OP(RDMA_WRITE_MIDDLE) ||
 370                     opcode == OP(RDMA_WRITE_LAST) ||
 371                     opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
 372                         break;
 373                 goto inv;
 374
 375         default:
 376                 if (opcode == OP(SEND_FIRST) ||
 377                     opcode == OP(SEND_ONLY) ||
 378                     opcode == OP(SEND_ONLY_WITH_IMMEDIATE) ||
 379                     opcode == OP(RDMA_WRITE_FIRST) ||
 380                     opcode == OP(RDMA_WRITE_ONLY) ||
 381                     opcode == OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE))
 382                         break;
 383                 goto inv;
 384         }
 385
 386         if (qp->state == IB_QPS_RTR && !(qp->r_flags & RVT_R_COMM_EST))
 387                 qp_comm_est(qp);
 388
 389         /* OK, process the packet. */
 390         switch (opcode) {
 391         case OP(SEND_FIRST):
 392         case OP(SEND_ONLY):
 393         case OP(SEND_ONLY_WITH_IMMEDIATE):
 394 send_first:
 395                 if (test_and_clear_bit(RVT_R_REWIND_SGE, &qp->r_aflags)) {
 396                         qp->r_sge = qp->s_rdma_read_sge;
 397                 } else {
 398                         ret = hfi1_rvt_get_rwqe(qp, 0);
 399                         if (ret < 0)
 400                                 goto op_err;
 401                         if (!ret)
 402                                 goto drop;
 403                         /*
 404                          * qp->s_rdma_read_sge will be the owner
 405                          * of the mr references.
 406                          */
 407                         qp->s_rdma_read_sge = qp->r_sge;
 408                 }
 409                 qp->r_rcv_len = 0;
 410                 if (opcode == OP(SEND_ONLY))
 411                         goto no_immediate_data;
 412                 else if (opcode == OP(SEND_ONLY_WITH_IMMEDIATE))
 413                         goto send_last_imm;
 414                 /* FALLTHROUGH */
 415         case OP(SEND_MIDDLE):
 416                 /* Check for invalid length PMTU or posted rwqe len. */
 417                 if (unlikely(tlen != (hdrsize + pmtu + 4)))
 418                         goto rewind;
 419                 qp->r_rcv_len += pmtu;
 420                 if (unlikely(qp->r_rcv_len > qp->r_len))
 421                         goto rewind;
 422                 hfi1_copy_sge(&qp->r_sge, data, pmtu, 0, 0);
 423                 break;
 424
 425         case OP(SEND_LAST_WITH_IMMEDIATE):
 426 send_last_imm:
 427                 wc.ex.imm_data = ohdr->u.imm_data;
 428                 wc.wc_flags = IB_WC_WITH_IMM;
 429                 goto send_last;
 430         case OP(SEND_LAST):
 431 no_immediate_data:
 432                 wc.ex.imm_data = 0;
 433                 wc.wc_flags = 0;
 434 send_last:
 435                 /* Get the number of bytes the message was padded by. */
 436                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
 437                 /* Check for invalid length. */
 438                 /* LAST len should be >= 1 */
 439                 if (unlikely(tlen < (hdrsize + pad + 4)))
 440                         goto rewind;
 441                 /* Don't count the CRC. */
 442                 tlen -= (hdrsize + pad + 4);
 443                 wc.byte_len = tlen + qp->r_rcv_len;
 444                 if (unlikely(wc.byte_len > qp->r_len))
 445                         goto rewind;
 446                 wc.opcode = IB_WC_RECV;
 447                 hfi1_copy_sge(&qp->r_sge, data, tlen, 0, 0);
 448                 rvt_put_ss(&qp->s_rdma_read_sge);
 449 last_imm:
 450                 wc.wr_id = qp->r_wr_id;
 451                 wc.status = IB_WC_SUCCESS;
 452                 wc.qp = &qp->ibqp;
 453                 wc.src_qp = qp->remote_qpn;
 454                 wc.slid = qp->remote_ah_attr.dlid;
 455                 /*
 456                  * It seems that IB mandates the presence of an SL in a
 457                  * work completion only for the UD transport (see section
 458                  * 11.4.2 of IBTA Vol. 1).
 459                  *
 460                  * However, the way the SL is chosen below is consistent
 461                  * with the way that IB/qib works and is trying avoid
 462                  * introducing incompatibilities.
 463                  *
 464                  * See also OPA Vol. 1, section 9.7.6, and table 9-17.
 465                  */
 466                 wc.sl = qp->remote_ah_attr.sl;
 467                 /* zero fields that are N/A */
 468                 wc.vendor_err = 0;
 469                 wc.pkey_index = 0;
 470                 wc.dlid_path_bits = 0;
 471                 wc.port_num = 0;
 472                 /* Signal completion event if the solicited bit is set. */
 473                 rvt_cq_enter(ibcq_to_rvtcq(qp->ibqp.recv_cq), &wc,
 474                              (ohdr->bth[0] &
 475                               cpu_to_be32(IB_BTH_SOLICITED)) != 0);
 476                 break;
 477
 478         case OP(RDMA_WRITE_FIRST):
 479         case OP(RDMA_WRITE_ONLY):
 480         case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE): /* consume RWQE */
 481 rdma_first:
 482                 if (unlikely(!(qp->qp_access_flags &
 483                                IB_ACCESS_REMOTE_WRITE))) {
 484                         goto drop;
 485                 }
 486                 reth = &ohdr->u.rc.reth;
 487                 qp->r_len = be32_to_cpu(reth->length);
 488                 qp->r_rcv_len = 0;
 489                 qp->r_sge.sg_list = NULL;
 490                 if (qp->r_len != 0) {
 491                         u32 rkey = be32_to_cpu(reth->rkey);
 492                         u64 vaddr = be64_to_cpu(reth->vaddr);
 493                         int ok;
 494
 495                         /* Check rkey */
 496                         ok = rvt_rkey_ok(qp, &qp->r_sge.sge, qp->r_len,
 497                                          vaddr, rkey, IB_ACCESS_REMOTE_WRITE);
 498                         if (unlikely(!ok))
 499                                 goto drop;
 500                         qp->r_sge.num_sge = 1;
 501                 } else {
 502                         qp->r_sge.num_sge = 0;
 503                         qp->r_sge.sge.mr = NULL;
 504                         qp->r_sge.sge.vaddr = NULL;
 505                         qp->r_sge.sge.length = 0;
 506                         qp->r_sge.sge.sge_length = 0;
 507                 }
 508                 if (opcode == OP(RDMA_WRITE_ONLY)) {
 509                         goto rdma_last;
 510                 } else if (opcode == OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE)) {
 511                         wc.ex.imm_data = ohdr->u.rc.imm_data;
 512                         goto rdma_last_imm;
 513                 }
 514                 /* FALLTHROUGH */
 515         case OP(RDMA_WRITE_MIDDLE):
 516                 /* Check for invalid length PMTU or posted rwqe len. */
 517                 if (unlikely(tlen != (hdrsize + pmtu + 4)))
 518                         goto drop;
 519                 qp->r_rcv_len += pmtu;
 520                 if (unlikely(qp->r_rcv_len > qp->r_len))
 521                         goto drop;
 522                 hfi1_copy_sge(&qp->r_sge, data, pmtu, 1, 0);
 523                 break;
 524
 525         case OP(RDMA_WRITE_LAST_WITH_IMMEDIATE):
 526                 wc.ex.imm_data = ohdr->u.imm_data;
 527 rdma_last_imm:
 528                 wc.wc_flags = IB_WC_WITH_IMM;
 529
 530                 /* Get the number of bytes the message was padded by. */
 531                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
 532                 /* Check for invalid length. */
 533                 /* LAST len should be >= 1 */
 534                 if (unlikely(tlen < (hdrsize + pad + 4)))
 535                         goto drop;
 536                 /* Don't count the CRC. */
 537                 tlen -= (hdrsize + pad + 4);
 538                 if (unlikely(tlen + qp->r_rcv_len != qp->r_len))
 539                         goto drop;
 540                 if (test_and_clear_bit(RVT_R_REWIND_SGE, &qp->r_aflags)) {
 541                         rvt_put_ss(&qp->s_rdma_read_sge);
 542                 } else {
 543                         ret = hfi1_rvt_get_rwqe(qp, 1);
 544                         if (ret < 0)
 545                                 goto op_err;
 546                         if (!ret)
 547                                 goto drop;
 548                 }
 549                 wc.byte_len = qp->r_len;
 550                 wc.opcode = IB_WC_RECV_RDMA_WITH_IMM;
 551                 hfi1_copy_sge(&qp->r_sge, data, tlen, 1, 0);
 552                 rvt_put_ss(&qp->r_sge);
 553                 goto last_imm;
 554
 555         case OP(RDMA_WRITE_LAST):
 556 rdma_last:
 557                 /* Get the number of bytes the message was padded by. */
 558                 pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
 559                 /* Check for invalid length. */
 560                 /* LAST len should be >= 1 */
 561                 if (unlikely(tlen < (hdrsize + pad + 4)))
 562                         goto drop;
 563                 /* Don't count the CRC. */
 564                 tlen -= (hdrsize + pad + 4);
 565                 if (unlikely(tlen + qp->r_rcv_len != qp->r_len))
 566                         goto drop;
 567                 hfi1_copy_sge(&qp->r_sge, data, tlen, 1, 0);
 568                 rvt_put_ss(&qp->r_sge);
 569                 break;
 570
 571         default:
 572                 /* Drop packet for unknown opcodes. */
 573                 goto drop;
 574         }
 575         qp->r_psn++;
 576         qp->r_state = opcode;
 577         return;
 578
 579 rewind:
 580         set_bit(RVT_R_REWIND_SGE, &qp->r_aflags);
 581         qp->r_sge.num_sge = 0;
 582 drop:
 583         ibp->rvp.n_pkt_drops++;
 584         return;
 585
 586 op_err:
 587         hfi1_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
 588 }