drivers/infiniband/hw/qib/qib_ud.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 <rdma/ib_smi.h>
  35 #include <rdma/ib_verbs.h>
  36
  37 #include "qib.h"
  38 #include "qib_mad.h"
  39
  40 /**
  41  * qib_ud_loopback - handle send on loopback QPs
  42  * @sqp: the sending QP
  43  * @swqe: the send work request
  44  *
  45  * This is called from qib_make_ud_req() to forward a WQE addressed
  46  * to the same HCA.
  47  * Note that the receive interrupt handler may be calling qib_ud_rcv()
  48  * while this is being called.
  49  */
  50 static void qib_ud_loopback(struct rvt_qp *sqp, struct rvt_swqe *swqe)
  51 {
  52         struct qib_ibport *ibp = to_iport(sqp->ibqp.device, sqp->port_num);
  53         struct qib_pportdata *ppd = ppd_from_ibp(ibp);
  54         struct qib_devdata *dd = ppd->dd;
  55         struct rvt_dev_info *rdi = &dd->verbs_dev.rdi;
  56         struct rvt_qp *qp;
  57         struct ib_ah_attr *ah_attr;
  58         unsigned long flags;
  59         struct rvt_sge_state ssge;
  60         struct rvt_sge *sge;
  61         struct ib_wc wc;
  62         u32 length;
  63         enum ib_qp_type sqptype, dqptype;
  64
  65         rcu_read_lock();
  66         qp = rvt_lookup_qpn(rdi, &ibp->rvp, swqe->ud_wr.remote_qpn);
  67         if (!qp) {
  68                 ibp->rvp.n_pkt_drops++;
  69                 rcu_read_unlock();
  70                 return;
  71         }
  72
  73         sqptype = sqp->ibqp.qp_type == IB_QPT_GSI ?
  74                         IB_QPT_UD : sqp->ibqp.qp_type;
  75         dqptype = qp->ibqp.qp_type == IB_QPT_GSI ?
  76                         IB_QPT_UD : qp->ibqp.qp_type;
  77
  78         if (dqptype != sqptype ||
  79             !(ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK)) {
  80                 ibp->rvp.n_pkt_drops++;
  81                 goto drop;
  82         }
  83
  84         ah_attr = &ibah_to_rvtah(swqe->ud_wr.ah)->attr;
  85         ppd = ppd_from_ibp(ibp);
  86
  87         if (qp->ibqp.qp_num > 1) {
  88                 u16 pkey1;
  89                 u16 pkey2;
  90                 u16 lid;
  91
  92                 pkey1 = qib_get_pkey(ibp, sqp->s_pkey_index);
  93                 pkey2 = qib_get_pkey(ibp, qp->s_pkey_index);
  94                 if (unlikely(!qib_pkey_ok(pkey1, pkey2))) {
  95                         lid = ppd->lid | (ah_attr->src_path_bits &
  96                                           ((1 << ppd->lmc) - 1));
  97                         qib_bad_pqkey(ibp, IB_NOTICE_TRAP_BAD_PKEY, pkey1,
  98                                       ah_attr->sl,
  99                                       sqp->ibqp.qp_num, qp->ibqp.qp_num,
 100                                       cpu_to_be16(lid),
 101                                       cpu_to_be16(ah_attr->dlid));
 102                         goto drop;
 103                 }
 104         }
 105
 106         /*
 107          * Check that the qkey matches (except for QP0, see 9.6.1.4.1).
 108          * Qkeys with the high order bit set mean use the
 109          * qkey from the QP context instead of the WR (see 10.2.5).
 110          */
 111         if (qp->ibqp.qp_num) {
 112                 u32 qkey;
 113
 114                 qkey = (int)swqe->ud_wr.remote_qkey < 0 ?
 115                         sqp->qkey : swqe->ud_wr.remote_qkey;
 116                 if (unlikely(qkey != qp->qkey)) {
 117                         u16 lid;
 118
 119                         lid = ppd->lid | (ah_attr->src_path_bits &
 120                                           ((1 << ppd->lmc) - 1));
 121                         qib_bad_pqkey(ibp, IB_NOTICE_TRAP_BAD_QKEY, qkey,
 122                                       ah_attr->sl,
 123                                       sqp->ibqp.qp_num, qp->ibqp.qp_num,
 124                                       cpu_to_be16(lid),
 125                                       cpu_to_be16(ah_attr->dlid));
 126                         goto drop;
 127                 }
 128         }
 129
 130         /*
 131          * A GRH is expected to precede the data even if not
 132          * present on the wire.
 133          */
 134         length = swqe->length;
 135         memset(&wc, 0, sizeof(wc));
 136         wc.byte_len = length + sizeof(struct ib_grh);
 137
 138         if (swqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
 139                 wc.wc_flags = IB_WC_WITH_IMM;
 140                 wc.ex.imm_data = swqe->wr.ex.imm_data;
 141         }
 142
 143         spin_lock_irqsave(&qp->r_lock, flags);
 144
 145         /*
 146          * Get the next work request entry to find where to put the data.
 147          */
 148         if (qp->r_flags & RVT_R_REUSE_SGE)
 149                 qp->r_flags &= ~RVT_R_REUSE_SGE;
 150         else {
 151                 int ret;
 152
 153                 ret = qib_get_rwqe(qp, 0);
 154                 if (ret < 0) {
 155                         qib_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
 156                         goto bail_unlock;
 157                 }
 158                 if (!ret) {
 159                         if (qp->ibqp.qp_num == 0)
 160                                 ibp->rvp.n_vl15_dropped++;
 161                         goto bail_unlock;
 162                 }
 163         }
 164         /* Silently drop packets which are too big. */
 165         if (unlikely(wc.byte_len > qp->r_len)) {
 166                 qp->r_flags |= RVT_R_REUSE_SGE;
 167                 ibp->rvp.n_pkt_drops++;
 168                 goto bail_unlock;
 169         }
 170
 171         if (ah_attr->ah_flags & IB_AH_GRH) {
 172                 struct ib_grh grh;
 173                 struct ib_global_route grd = ah_attr->grh;
 174
 175                 qib_make_grh(ibp, &grh, &grd, 0, 0);
 176                 qib_copy_sge(&qp->r_sge, &grh,
 177                              sizeof(grh), 1);
 178                 wc.wc_flags |= IB_WC_GRH;
 179         } else
 180                 qib_skip_sge(&qp->r_sge, sizeof(struct ib_grh), 1);
 181         ssge.sg_list = swqe->sg_list + 1;
 182         ssge.sge = *swqe->sg_list;
 183         ssge.num_sge = swqe->wr.num_sge;
 184         sge = &ssge.sge;
 185         while (length) {
 186                 u32 len = sge->length;
 187
 188                 if (len > length)
 189                         len = length;
 190                 if (len > sge->sge_length)
 191                         len = sge->sge_length;
 192                 BUG_ON(len == 0);
 193                 qib_copy_sge(&qp->r_sge, sge->vaddr, len, 1);
 194                 sge->vaddr += len;
 195                 sge->length -= len;
 196                 sge->sge_length -= len;
 197                 if (sge->sge_length == 0) {
 198                         if (--ssge.num_sge)
 199                                 *sge = *ssge.sg_list++;
 200                 } else if (sge->length == 0 && sge->mr->lkey) {
 201                         if (++sge->n >= RVT_SEGSZ) {
 202                                 if (++sge->m >= sge->mr->mapsz)
 203                                         break;
 204                                 sge->n = 0;
 205                         }
 206                         sge->vaddr =
 207                                 sge->mr->map[sge->m]->segs[sge->n].vaddr;
 208                         sge->length =
 209                                 sge->mr->map[sge->m]->segs[sge->n].length;
 210                 }
 211                 length -= len;
 212         }
 213         rvt_put_ss(&qp->r_sge);
 214         if (!test_and_clear_bit(RVT_R_WRID_VALID, &qp->r_aflags))
 215                 goto bail_unlock;
 216         wc.wr_id = qp->r_wr_id;
 217         wc.status = IB_WC_SUCCESS;
 218         wc.opcode = IB_WC_RECV;
 219         wc.qp = &qp->ibqp;
 220         wc.src_qp = sqp->ibqp.qp_num;
 221         wc.pkey_index = qp->ibqp.qp_type == IB_QPT_GSI ?
 222                 swqe->ud_wr.pkey_index : 0;
 223         wc.slid = ppd->lid | (ah_attr->src_path_bits & ((1 << ppd->lmc) - 1));
 224         wc.sl = ah_attr->sl;
 225         wc.dlid_path_bits = ah_attr->dlid & ((1 << ppd->lmc) - 1);
 226         wc.port_num = qp->port_num;
 227         /* Signal completion event if the solicited bit is set. */
 228         rvt_cq_enter(ibcq_to_rvtcq(qp->ibqp.recv_cq), &wc,
 229                      swqe->wr.send_flags & IB_SEND_SOLICITED);
 230         ibp->rvp.n_loop_pkts++;
 231 bail_unlock:
 232         spin_unlock_irqrestore(&qp->r_lock, flags);
 233 drop:
 234         rcu_read_unlock();
 235 }
 236
 237 /**
 238  * qib_make_ud_req - construct a UD request packet
 239  * @qp: the QP
 240  *
 241  * Assumes the s_lock is held.
 242  *
 243  * Return 1 if constructed; otherwise, return 0.
 244  */
 245 int qib_make_ud_req(struct rvt_qp *qp, unsigned long *flags)
 246 {
 247         struct qib_qp_priv *priv = qp->priv;
 248         struct qib_other_headers *ohdr;
 249         struct ib_ah_attr *ah_attr;
 250         struct qib_pportdata *ppd;
 251         struct qib_ibport *ibp;
 252         struct rvt_swqe *wqe;
 253         u32 nwords;
 254         u32 extra_bytes;
 255         u32 bth0;
 256         u16 lrh0;
 257         u16 lid;
 258         int ret = 0;
 259         int next_cur;
 260
 261         if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_NEXT_SEND_OK)) {
 262                 if (!(ib_rvt_state_ops[qp->state] & RVT_FLUSH_SEND))
 263                         goto bail;
 264                 /* We are in the error state, flush the work request. */
 265                 smp_read_barrier_depends(); /* see post_one_send */
 266                 if (qp->s_last == ACCESS_ONCE(qp->s_head))
 267                         goto bail;
 268                 /* If DMAs are in progress, we can't flush immediately. */
 269                 if (atomic_read(&priv->s_dma_busy)) {
 270                         qp->s_flags |= RVT_S_WAIT_DMA;
 271                         goto bail;
 272                 }
 273                 wqe = rvt_get_swqe_ptr(qp, qp->s_last);
 274                 qib_send_complete(qp, wqe, IB_WC_WR_FLUSH_ERR);
 275                 goto done;
 276         }
 277
 278         /* see post_one_send() */
 279         smp_read_barrier_depends();
 280         if (qp->s_cur == ACCESS_ONCE(qp->s_head))
 281                 goto bail;
 282
 283         wqe = rvt_get_swqe_ptr(qp, qp->s_cur);
 284         next_cur = qp->s_cur + 1;
 285         if (next_cur >= qp->s_size)
 286                 next_cur = 0;
 287
 288         /* Construct the header. */
 289         ibp = to_iport(qp->ibqp.device, qp->port_num);
 290         ppd = ppd_from_ibp(ibp);
 291         ah_attr = &ibah_to_rvtah(wqe->ud_wr.ah)->attr;
 292         if (ah_attr->dlid >= be16_to_cpu(IB_MULTICAST_LID_BASE)) {
 293                 if (ah_attr->dlid != be16_to_cpu(IB_LID_PERMISSIVE))
 294                         this_cpu_inc(ibp->pmastats->n_multicast_xmit);
 295                 else
 296                         this_cpu_inc(ibp->pmastats->n_unicast_xmit);
 297         } else {
 298                 this_cpu_inc(ibp->pmastats->n_unicast_xmit);
 299                 lid = ah_attr->dlid & ~((1 << ppd->lmc) - 1);
 300                 if (unlikely(lid == ppd->lid)) {
 301                         unsigned long tflags = *flags;
 302                         /*
 303                          * If DMAs are in progress, we can't generate
 304                          * a completion for the loopback packet since
 305                          * it would be out of order.
 306                          * XXX Instead of waiting, we could queue a
 307                          * zero length descriptor so we get a callback.
 308                          */
 309                         if (atomic_read(&priv->s_dma_busy)) {
 310                                 qp->s_flags |= RVT_S_WAIT_DMA;
 311                                 goto bail;
 312                         }
 313                         qp->s_cur = next_cur;
 314                         spin_unlock_irqrestore(&qp->s_lock, tflags);
 315                         qib_ud_loopback(qp, wqe);
 316                         spin_lock_irqsave(&qp->s_lock, tflags);
 317                         *flags = tflags;
 318                         qib_send_complete(qp, wqe, IB_WC_SUCCESS);
 319                         goto done;
 320                 }
 321         }
 322
 323         qp->s_cur = next_cur;
 324         extra_bytes = -wqe->length & 3;
 325         nwords = (wqe->length + extra_bytes) >> 2;
 326
 327         /* header size in 32-bit words LRH+BTH+DETH = (8+12+8)/4. */
 328         qp->s_hdrwords = 7;
 329         qp->s_cur_size = wqe->length;
 330         qp->s_cur_sge = &qp->s_sge;
 331         qp->s_srate = ah_attr->static_rate;
 332         qp->s_wqe = wqe;
 333         qp->s_sge.sge = wqe->sg_list[0];
 334         qp->s_sge.sg_list = wqe->sg_list + 1;
 335         qp->s_sge.num_sge = wqe->wr.num_sge;
 336         qp->s_sge.total_len = wqe->length;
 337
 338         if (ah_attr->ah_flags & IB_AH_GRH) {
 339                 /* Header size in 32-bit words. */
 340                 qp->s_hdrwords += qib_make_grh(ibp, &priv->s_hdr->u.l.grh,
 341                                                &ah_attr->grh,
 342                                                qp->s_hdrwords, nwords);
 343                 lrh0 = QIB_LRH_GRH;
 344                 ohdr = &priv->s_hdr->u.l.oth;
 345                 /*
 346                  * Don't worry about sending to locally attached multicast
 347                  * QPs.  It is unspecified by the spec. what happens.
 348                  */
 349         } else {
 350                 /* Header size in 32-bit words. */
 351                 lrh0 = QIB_LRH_BTH;
 352                 ohdr = &priv->s_hdr->u.oth;
 353         }
 354         if (wqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
 355                 qp->s_hdrwords++;
 356                 ohdr->u.ud.imm_data = wqe->wr.ex.imm_data;
 357                 bth0 = IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE << 24;
 358         } else
 359                 bth0 = IB_OPCODE_UD_SEND_ONLY << 24;
 360         lrh0 |= ah_attr->sl << 4;
 361         if (qp->ibqp.qp_type == IB_QPT_SMI)
 362                 lrh0 |= 0xF000; /* Set VL (see ch. 13.5.3.1) */
 363         else
 364                 lrh0 |= ibp->sl_to_vl[ah_attr->sl] << 12;
 365         priv->s_hdr->lrh[0] = cpu_to_be16(lrh0);
 366         priv->s_hdr->lrh[1] = cpu_to_be16(ah_attr->dlid);  /* DEST LID */
 367         priv->s_hdr->lrh[2] =
 368                         cpu_to_be16(qp->s_hdrwords + nwords + SIZE_OF_CRC);
 369         lid = ppd->lid;
 370         if (lid) {
 371                 lid |= ah_attr->src_path_bits & ((1 << ppd->lmc) - 1);
 372                 priv->s_hdr->lrh[3] = cpu_to_be16(lid);
 373         } else
 374                 priv->s_hdr->lrh[3] = IB_LID_PERMISSIVE;
 375         if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 376                 bth0 |= IB_BTH_SOLICITED;
 377         bth0 |= extra_bytes << 20;
 378         bth0 |= qp->ibqp.qp_type == IB_QPT_SMI ? QIB_DEFAULT_P_KEY :
 379                 qib_get_pkey(ibp, qp->ibqp.qp_type == IB_QPT_GSI ?
 380                              wqe->ud_wr.pkey_index : qp->s_pkey_index);
 381         ohdr->bth[0] = cpu_to_be32(bth0);
 382         /*
 383          * Use the multicast QP if the destination LID is a multicast LID.
 384          */
 385         ohdr->bth[1] = ah_attr->dlid >= be16_to_cpu(IB_MULTICAST_LID_BASE) &&
 386                 ah_attr->dlid != be16_to_cpu(IB_LID_PERMISSIVE) ?
 387                 cpu_to_be32(QIB_MULTICAST_QPN) :
 388                 cpu_to_be32(wqe->ud_wr.remote_qpn);
 389         ohdr->bth[2] = cpu_to_be32(wqe->psn & QIB_PSN_MASK);
 390         /*
 391          * Qkeys with the high order bit set mean use the
 392          * qkey from the QP context instead of the WR (see 10.2.5).
 393          */
 394         ohdr->u.ud.deth[0] = cpu_to_be32((int)wqe->ud_wr.remote_qkey < 0 ?
 395                                          qp->qkey : wqe->ud_wr.remote_qkey);
 396         ohdr->u.ud.deth[1] = cpu_to_be32(qp->ibqp.qp_num);
 397
 398 done:
 399         return 1;
 400 bail:
 401         qp->s_flags &= ~RVT_S_BUSY;
 402         return ret;
 403 }
 404
 405 static unsigned qib_lookup_pkey(struct qib_ibport *ibp, u16 pkey)
 406 {
 407         struct qib_pportdata *ppd = ppd_from_ibp(ibp);
 408         struct qib_devdata *dd = ppd->dd;
 409         unsigned ctxt = ppd->hw_pidx;
 410         unsigned i;
 411
 412         pkey &= 0x7fff; /* remove limited/full membership bit */
 413
 414         for (i = 0; i < ARRAY_SIZE(dd->rcd[ctxt]->pkeys); ++i)
 415                 if ((dd->rcd[ctxt]->pkeys[i] & 0x7fff) == pkey)
 416                         return i;
 417
 418         /*
 419          * Should not get here, this means hardware failed to validate pkeys.
 420          * Punt and return index 0.
 421          */
 422         return 0;
 423 }
 424
 425 /**
 426  * qib_ud_rcv - receive an incoming UD packet
 427  * @ibp: the port the packet came in on
 428  * @hdr: the packet header
 429  * @has_grh: true if the packet has a GRH
 430  * @data: the packet data
 431  * @tlen: the packet length
 432  * @qp: the QP the packet came on
 433  *
 434  * This is called from qib_qp_rcv() to process an incoming UD packet
 435  * for the given QP.
 436  * Called at interrupt level.
 437  */
 438 void qib_ud_rcv(struct qib_ibport *ibp, struct qib_ib_header *hdr,
 439                 int has_grh, void *data, u32 tlen, struct rvt_qp *qp)
 440 {
 441         struct qib_other_headers *ohdr;
 442         int opcode;
 443         u32 hdrsize;
 444         u32 pad;
 445         struct ib_wc wc;
 446         u32 qkey;
 447         u32 src_qp;
 448         u16 dlid;
 449
 450         /* Check for GRH */
 451         if (!has_grh) {
 452                 ohdr = &hdr->u.oth;
 453                 hdrsize = 8 + 12 + 8;   /* LRH + BTH + DETH */
 454         } else {
 455                 ohdr = &hdr->u.l.oth;
 456                 hdrsize = 8 + 40 + 12 + 8; /* LRH + GRH + BTH + DETH */
 457         }
 458         qkey = be32_to_cpu(ohdr->u.ud.deth[0]);
 459         src_qp = be32_to_cpu(ohdr->u.ud.deth[1]) & RVT_QPN_MASK;
 460
 461         /*
 462          * Get the number of bytes the message was padded by
 463          * and drop incomplete packets.
 464          */
 465         pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
 466         if (unlikely(tlen < (hdrsize + pad + 4)))
 467                 goto drop;
 468
 469         tlen -= hdrsize + pad + 4;
 470
 471         /*
 472          * Check that the permissive LID is only used on QP0
 473          * and the QKEY matches (see 9.6.1.4.1 and 9.6.1.5.1).
 474          */
 475         if (qp->ibqp.qp_num) {
 476                 if (unlikely(hdr->lrh[1] == IB_LID_PERMISSIVE ||
 477                              hdr->lrh[3] == IB_LID_PERMISSIVE))
 478                         goto drop;
 479                 if (qp->ibqp.qp_num > 1) {
 480                         u16 pkey1, pkey2;
 481
 482                         pkey1 = be32_to_cpu(ohdr->bth[0]);
 483                         pkey2 = qib_get_pkey(ibp, qp->s_pkey_index);
 484                         if (unlikely(!qib_pkey_ok(pkey1, pkey2))) {
 485                                 qib_bad_pqkey(ibp, IB_NOTICE_TRAP_BAD_PKEY,
 486                                               pkey1,
 487                                               (be16_to_cpu(hdr->lrh[0]) >> 4) &
 488                                                 0xF,
 489                                               src_qp, qp->ibqp.qp_num,
 490                                               hdr->lrh[3], hdr->lrh[1]);
 491                                 return;
 492                         }
 493                 }
 494                 if (unlikely(qkey != qp->qkey)) {
 495                         qib_bad_pqkey(ibp, IB_NOTICE_TRAP_BAD_QKEY, qkey,
 496                                       (be16_to_cpu(hdr->lrh[0]) >> 4) & 0xF,
 497                                       src_qp, qp->ibqp.qp_num,
 498                                       hdr->lrh[3], hdr->lrh[1]);
 499                         return;
 500                 }
 501                 /* Drop invalid MAD packets (see 13.5.3.1). */
 502                 if (unlikely(qp->ibqp.qp_num == 1 &&
 503                              (tlen != 256 ||
 504                               (be16_to_cpu(hdr->lrh[0]) >> 12) == 15)))
 505                         goto drop;
 506         } else {
 507                 struct ib_smp *smp;
 508
 509                 /* Drop invalid MAD packets (see 13.5.3.1). */
 510                 if (tlen != 256 || (be16_to_cpu(hdr->lrh[0]) >> 12) != 15)
 511                         goto drop;
 512                 smp = (struct ib_smp *) data;
 513                 if ((hdr->lrh[1] == IB_LID_PERMISSIVE ||
 514                      hdr->lrh[3] == IB_LID_PERMISSIVE) &&
 515                     smp->mgmt_class != IB_MGMT_CLASS_SUBN_DIRECTED_ROUTE)
 516                         goto drop;
 517         }
 518
 519         /*
 520          * The opcode is in the low byte when its in network order
 521          * (top byte when in host order).
 522          */
 523         opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
 524         if (qp->ibqp.qp_num > 1 &&
 525             opcode == IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE) {
 526                 wc.ex.imm_data = ohdr->u.ud.imm_data;
 527                 wc.wc_flags = IB_WC_WITH_IMM;
 528                 tlen -= sizeof(u32);
 529         } else if (opcode == IB_OPCODE_UD_SEND_ONLY) {
 530                 wc.ex.imm_data = 0;
 531                 wc.wc_flags = 0;
 532         } else
 533                 goto drop;
 534
 535         /*
 536          * A GRH is expected to precede the data even if not
 537          * present on the wire.
 538          */
 539         wc.byte_len = tlen + sizeof(struct ib_grh);
 540
 541         /*
 542          * Get the next work request entry to find where to put the data.
 543          */
 544         if (qp->r_flags & RVT_R_REUSE_SGE)
 545                 qp->r_flags &= ~RVT_R_REUSE_SGE;
 546         else {
 547                 int ret;
 548
 549                 ret = qib_get_rwqe(qp, 0);
 550                 if (ret < 0) {
 551                         qib_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
 552                         return;
 553                 }
 554                 if (!ret) {
 555                         if (qp->ibqp.qp_num == 0)
 556                                 ibp->rvp.n_vl15_dropped++;
 557                         return;
 558                 }
 559         }
 560         /* Silently drop packets which are too big. */
 561         if (unlikely(wc.byte_len > qp->r_len)) {
 562                 qp->r_flags |= RVT_R_REUSE_SGE;
 563                 goto drop;
 564         }
 565         if (has_grh) {
 566                 qib_copy_sge(&qp->r_sge, &hdr->u.l.grh,
 567                              sizeof(struct ib_grh), 1);
 568                 wc.wc_flags |= IB_WC_GRH;
 569         } else
 570                 qib_skip_sge(&qp->r_sge, sizeof(struct ib_grh), 1);
 571         qib_copy_sge(&qp->r_sge, data, wc.byte_len - sizeof(struct ib_grh), 1);
 572         rvt_put_ss(&qp->r_sge);
 573         if (!test_and_clear_bit(RVT_R_WRID_VALID, &qp->r_aflags))
 574                 return;
 575         wc.wr_id = qp->r_wr_id;
 576         wc.status = IB_WC_SUCCESS;
 577         wc.opcode = IB_WC_RECV;
 578         wc.vendor_err = 0;
 579         wc.qp = &qp->ibqp;
 580         wc.src_qp = src_qp;
 581         wc.pkey_index = qp->ibqp.qp_type == IB_QPT_GSI ?
 582                 qib_lookup_pkey(ibp, be32_to_cpu(ohdr->bth[0])) : 0;
 583         wc.slid = be16_to_cpu(hdr->lrh[3]);
 584         wc.sl = (be16_to_cpu(hdr->lrh[0]) >> 4) & 0xF;
 585         dlid = be16_to_cpu(hdr->lrh[1]);
 586         /*
 587          * Save the LMC lower bits if the destination LID is a unicast LID.
 588          */
 589         wc.dlid_path_bits = dlid >= be16_to_cpu(IB_MULTICAST_LID_BASE) ? 0 :
 590                 dlid & ((1 << ppd_from_ibp(ibp)->lmc) - 1);
 591         wc.port_num = qp->port_num;
 592         /* Signal completion event if the solicited bit is set. */
 593         rvt_cq_enter(ibcq_to_rvtcq(qp->ibqp.recv_cq), &wc,
 594                      (ohdr->bth[0] &
 595                         cpu_to_be32(IB_BTH_SOLICITED)) != 0);
 596         return;
 597
 598 drop:
 599         ibp->rvp.n_pkt_drops++;
 600 }