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