git.oblomov.eu Git - linux-2.6/blob - drivers/infiniband/hw/ipath/ipath_ud.c

   1 /*
   2  * Copyright (c) 2006, 2007, 2008 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
  36 #include "ipath_verbs.h"
  37 #include "ipath_kernel.h"
  38
  39 /**
  40  * ipath_ud_loopback - handle send on loopback QPs
  41  * @sqp: the sending QP
  42  * @swqe: the send work request
  43  *
  44  * This is called from ipath_make_ud_req() to forward a WQE addressed
  45  * to the same HCA.
  46  * Note that the receive interrupt handler may be calling ipath_ud_rcv()
  47  * while this is being called.
  48  */
  49 static void ipath_ud_loopback(struct ipath_qp *sqp, struct ipath_swqe *swqe)
  50 {
  51         struct ipath_ibdev *dev = to_idev(sqp->ibqp.device);
  52         struct ipath_qp *qp;
  53         struct ib_ah_attr *ah_attr;
  54         unsigned long flags;
  55         struct ipath_rq *rq;
  56         struct ipath_srq *srq;
  57         struct ipath_sge_state rsge;
  58         struct ipath_sge *sge;
  59         struct ipath_rwq *wq;
  60         struct ipath_rwqe *wqe;
  61         void (*handler)(struct ib_event *, void *);
  62         struct ib_wc wc;
  63         u32 tail;
  64         u32 rlen;
  65         u32 length;
  66
  67         qp = ipath_lookup_qpn(&dev->qp_table, swqe->wr.wr.ud.remote_qpn);
  68         if (!qp || !(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_RECV_OK)) {
  69                 dev->n_pkt_drops++;
  70                 goto done;
  71         }
  72
  73         rsge.sg_list = NULL;
  74
  75         /*
  76          * Check that the qkey matches (except for QP0, see 9.6.1.4.1).
  77          * Qkeys with the high order bit set mean use the
  78          * qkey from the QP context instead of the WR (see 10.2.5).
  79          */
  80         if (unlikely(qp->ibqp.qp_num &&
  81                      ((int) swqe->wr.wr.ud.remote_qkey < 0 ?
  82                       sqp->qkey : swqe->wr.wr.ud.remote_qkey) != qp->qkey)) {
  83                 /* XXX OK to lose a count once in a while. */
  84                 dev->qkey_violations++;
  85                 dev->n_pkt_drops++;
  86                 goto drop;
  87         }
  88
  89         /*
  90          * A GRH is expected to preceed the data even if not
  91          * present on the wire.
  92          */
  93         length = swqe->length;
  94         memset(&wc, 0, sizeof wc);
  95         wc.byte_len = length + sizeof(struct ib_grh);
  96
  97         if (swqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
  98                 wc.wc_flags = IB_WC_WITH_IMM;
  99                 wc.ex.imm_data = swqe->wr.ex.imm_data;
 100         }
 101
 102         /*
 103          * This would be a lot simpler if we could call ipath_get_rwqe()
 104          * but that uses state that the receive interrupt handler uses
 105          * so we would need to lock out receive interrupts while doing
 106          * local loopback.
 107          */
 108         if (qp->ibqp.srq) {
 109                 srq = to_isrq(qp->ibqp.srq);
 110                 handler = srq->ibsrq.event_handler;
 111                 rq = &srq->rq;
 112         } else {
 113                 srq = NULL;
 114                 handler = NULL;
 115                 rq = &qp->r_rq;
 116         }
 117
 118         if (rq->max_sge > 1) {
 119                 /*
 120                  * XXX We could use GFP_KERNEL if ipath_do_send()
 121                  * was always called from the tasklet instead of
 122                  * from ipath_post_send().
 123                  */
 124                 rsge.sg_list = kmalloc((rq->max_sge - 1) *
 125                                         sizeof(struct ipath_sge),
 126                                        GFP_ATOMIC);
 127                 if (!rsge.sg_list) {
 128                         dev->n_pkt_drops++;
 129                         goto drop;
 130                 }
 131         }
 132
 133         /*
 134          * Get the next work request entry to find where to put the data.
 135          * Note that it is safe to drop the lock after changing rq->tail
 136          * since ipath_post_receive() won't fill the empty slot.
 137          */
 138         spin_lock_irqsave(&rq->lock, flags);
 139         wq = rq->wq;
 140         tail = wq->tail;
 141         /* Validate tail before using it since it is user writable. */
 142         if (tail >= rq->size)
 143                 tail = 0;
 144         if (unlikely(tail == wq->head)) {
 145                 spin_unlock_irqrestore(&rq->lock, flags);
 146                 dev->n_pkt_drops++;
 147                 goto drop;
 148         }
 149         wqe = get_rwqe_ptr(rq, tail);
 150         if (!ipath_init_sge(qp, wqe, &rlen, &rsge)) {
 151                 spin_unlock_irqrestore(&rq->lock, flags);
 152                 dev->n_pkt_drops++;
 153                 goto drop;
 154         }
 155         /* Silently drop packets which are too big. */
 156         if (wc.byte_len > rlen) {
 157                 spin_unlock_irqrestore(&rq->lock, flags);
 158                 dev->n_pkt_drops++;
 159                 goto drop;
 160         }
 161         if (++tail >= rq->size)
 162                 tail = 0;
 163         wq->tail = tail;
 164         wc.wr_id = wqe->wr_id;
 165         if (handler) {
 166                 u32 n;
 167
 168                 /*
 169                  * validate head pointer value and compute
 170                  * the number of remaining WQEs.
 171                  */
 172                 n = wq->head;
 173                 if (n >= rq->size)
 174                         n = 0;
 175                 if (n < tail)
 176                         n += rq->size - tail;
 177                 else
 178                         n -= tail;
 179                 if (n < srq->limit) {
 180                         struct ib_event ev;
 181
 182                         srq->limit = 0;
 183                         spin_unlock_irqrestore(&rq->lock, flags);
 184                         ev.device = qp->ibqp.device;
 185                         ev.element.srq = qp->ibqp.srq;
 186                         ev.event = IB_EVENT_SRQ_LIMIT_REACHED;
 187                         handler(&ev, srq->ibsrq.srq_context);
 188                 } else
 189                         spin_unlock_irqrestore(&rq->lock, flags);
 190         } else
 191                 spin_unlock_irqrestore(&rq->lock, flags);
 192
 193         ah_attr = &to_iah(swqe->wr.wr.ud.ah)->attr;
 194         if (ah_attr->ah_flags & IB_AH_GRH) {
 195                 ipath_copy_sge(&rsge, &ah_attr->grh, sizeof(struct ib_grh));
 196                 wc.wc_flags |= IB_WC_GRH;
 197         } else
 198                 ipath_skip_sge(&rsge, sizeof(struct ib_grh));
 199         sge = swqe->sg_list;
 200         while (length) {
 201                 u32 len = sge->length;
 202
 203                 if (len > length)
 204                         len = length;
 205                 if (len > sge->sge_length)
 206                         len = sge->sge_length;
 207                 BUG_ON(len == 0);
 208                 ipath_copy_sge(&rsge, sge->vaddr, len);
 209                 sge->vaddr += len;
 210                 sge->length -= len;
 211                 sge->sge_length -= len;
 212                 if (sge->sge_length == 0) {
 213                         if (--swqe->wr.num_sge)
 214                                 sge++;
 215                 } else if (sge->length == 0 && sge->mr != NULL) {
 216                         if (++sge->n >= IPATH_SEGSZ) {
 217                                 if (++sge->m >= sge->mr->mapsz)
 218                                         break;
 219                                 sge->n = 0;
 220                         }
 221                         sge->vaddr =
 222                                 sge->mr->map[sge->m]->segs[sge->n].vaddr;
 223                         sge->length =
 224                                 sge->mr->map[sge->m]->segs[sge->n].length;
 225                 }
 226                 length -= len;
 227         }
 228         wc.status = IB_WC_SUCCESS;
 229         wc.opcode = IB_WC_RECV;
 230         wc.qp = &qp->ibqp;
 231         wc.src_qp = sqp->ibqp.qp_num;
 232         /* XXX do we know which pkey matched? Only needed for GSI. */
 233         wc.pkey_index = 0;
 234         wc.slid = dev->dd->ipath_lid |
 235                 (ah_attr->src_path_bits &
 236                  ((1 << dev->dd->ipath_lmc) - 1));
 237         wc.sl = ah_attr->sl;
 238         wc.dlid_path_bits =
 239                 ah_attr->dlid & ((1 << dev->dd->ipath_lmc) - 1);
 240         wc.port_num = 1;
 241         /* Signal completion event if the solicited bit is set. */
 242         ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
 243                        swqe->wr.send_flags & IB_SEND_SOLICITED);
 244 drop:
 245         kfree(rsge.sg_list);
 246         if (atomic_dec_and_test(&qp->refcount))
 247                 wake_up(&qp->wait);
 248 done:;
 249 }
 250
 251 /**
 252  * ipath_make_ud_req - construct a UD request packet
 253  * @qp: the QP
 254  *
 255  * Return 1 if constructed; otherwise, return 0.
 256  */
 257 int ipath_make_ud_req(struct ipath_qp *qp)
 258 {
 259         struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
 260         struct ipath_other_headers *ohdr;
 261         struct ib_ah_attr *ah_attr;
 262         struct ipath_swqe *wqe;
 263         unsigned long flags;
 264         u32 nwords;
 265         u32 extra_bytes;
 266         u32 bth0;
 267         u16 lrh0;
 268         u16 lid;
 269         int ret = 0;
 270         int next_cur;
 271
 272         spin_lock_irqsave(&qp->s_lock, flags);
 273
 274         if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_NEXT_SEND_OK)) {
 275                 if (!(ib_ipath_state_ops[qp->state] & IPATH_FLUSH_SEND))
 276                         goto bail;
 277                 /* We are in the error state, flush the work request. */
 278                 if (qp->s_last == qp->s_head)
 279                         goto bail;
 280                 /* If DMAs are in progress, we can't flush immediately. */
 281                 if (atomic_read(&qp->s_dma_busy)) {
 282                         qp->s_flags |= IPATH_S_WAIT_DMA;
 283                         goto bail;
 284                 }
 285                 wqe = get_swqe_ptr(qp, qp->s_last);
 286                 ipath_send_complete(qp, wqe, IB_WC_WR_FLUSH_ERR);
 287                 goto done;
 288         }
 289
 290         if (qp->s_cur == qp->s_head)
 291                 goto bail;
 292
 293         wqe = get_swqe_ptr(qp, qp->s_cur);
 294         next_cur = qp->s_cur + 1;
 295         if (next_cur >= qp->s_size)
 296                 next_cur = 0;
 297
 298         /* Construct the header. */
 299         ah_attr = &to_iah(wqe->wr.wr.ud.ah)->attr;
 300         if (ah_attr->dlid >= IPATH_MULTICAST_LID_BASE) {
 301                 if (ah_attr->dlid != IPATH_PERMISSIVE_LID)
 302                         dev->n_multicast_xmit++;
 303                 else
 304                         dev->n_unicast_xmit++;
 305         } else {
 306                 dev->n_unicast_xmit++;
 307                 lid = ah_attr->dlid & ~((1 << dev->dd->ipath_lmc) - 1);
 308                 if (unlikely(lid == dev->dd->ipath_lid)) {
 309                         /*
 310                          * If DMAs are in progress, we can't generate
 311                          * a completion for the loopback packet since
 312                          * it would be out of order.
 313                          * XXX Instead of waiting, we could queue a
 314                          * zero length descriptor so we get a callback.
 315                          */
 316                         if (atomic_read(&qp->s_dma_busy)) {
 317                                 qp->s_flags |= IPATH_S_WAIT_DMA;
 318                                 goto bail;
 319                         }
 320                         qp->s_cur = next_cur;
 321                         spin_unlock_irqrestore(&qp->s_lock, flags);
 322                         ipath_ud_loopback(qp, wqe);
 323                         spin_lock_irqsave(&qp->s_lock, flags);
 324                         ipath_send_complete(qp, wqe, IB_WC_SUCCESS);
 325                         goto done;
 326                 }
 327         }
 328
 329         qp->s_cur = next_cur;
 330         extra_bytes = -wqe->length & 3;
 331         nwords = (wqe->length + extra_bytes) >> 2;
 332
 333         /* header size in 32-bit words LRH+BTH+DETH = (8+12+8)/4. */
 334         qp->s_hdrwords = 7;
 335         qp->s_cur_size = wqe->length;
 336         qp->s_cur_sge = &qp->s_sge;
 337         qp->s_dmult = ah_attr->static_rate;
 338         qp->s_wqe = wqe;
 339         qp->s_sge.sge = wqe->sg_list[0];
 340         qp->s_sge.sg_list = wqe->sg_list + 1;
 341         qp->s_sge.num_sge = wqe->wr.num_sge;
 342
 343         if (ah_attr->ah_flags & IB_AH_GRH) {
 344                 /* Header size in 32-bit words. */
 345                 qp->s_hdrwords += ipath_make_grh(dev, &qp->s_hdr.u.l.grh,
 346                                                  &ah_attr->grh,
 347                                                  qp->s_hdrwords, nwords);
 348                 lrh0 = IPATH_LRH_GRH;
 349                 ohdr = &qp->s_hdr.u.l.oth;
 350                 /*
 351                  * Don't worry about sending to locally attached multicast
 352                  * QPs.  It is unspecified by the spec. what happens.
 353                  */
 354         } else {
 355                 /* Header size in 32-bit words. */
 356                 lrh0 = IPATH_LRH_BTH;
 357                 ohdr = &qp->s_hdr.u.oth;
 358         }
 359         if (wqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
 360                 qp->s_hdrwords++;
 361                 ohdr->u.ud.imm_data = wqe->wr.ex.imm_data;
 362                 bth0 = IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE << 24;
 363         } else
 364                 bth0 = IB_OPCODE_UD_SEND_ONLY << 24;
 365         lrh0 |= ah_attr->sl << 4;
 366         if (qp->ibqp.qp_type == IB_QPT_SMI)
 367                 lrh0 |= 0xF000; /* Set VL (see ch. 13.5.3.1) */
 368         qp->s_hdr.lrh[0] = cpu_to_be16(lrh0);
 369         qp->s_hdr.lrh[1] = cpu_to_be16(ah_attr->dlid);  /* DEST LID */
 370         qp->s_hdr.lrh[2] = cpu_to_be16(qp->s_hdrwords + nwords +
 371                                            SIZE_OF_CRC);
 372         lid = dev->dd->ipath_lid;
 373         if (lid) {
 374                 lid |= ah_attr->src_path_bits &
 375                         ((1 << dev->dd->ipath_lmc) - 1);
 376                 qp->s_hdr.lrh[3] = cpu_to_be16(lid);
 377         } else
 378                 qp->s_hdr.lrh[3] = IB_LID_PERMISSIVE;
 379         if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 380                 bth0 |= 1 << 23;
 381         bth0 |= extra_bytes << 20;
 382         bth0 |= qp->ibqp.qp_type == IB_QPT_SMI ? IPATH_DEFAULT_P_KEY :
 383                 ipath_get_pkey(dev->dd, qp->s_pkey_index);
 384         ohdr->bth[0] = cpu_to_be32(bth0);
 385         /*
 386          * Use the multicast QP if the destination LID is a multicast LID.
 387          */
 388         ohdr->bth[1] = ah_attr->dlid >= IPATH_MULTICAST_LID_BASE &&
 389                 ah_attr->dlid != IPATH_PERMISSIVE_LID ?
 390                 __constant_cpu_to_be32(IPATH_MULTICAST_QPN) :
 391                 cpu_to_be32(wqe->wr.wr.ud.remote_qpn);
 392         ohdr->bth[2] = cpu_to_be32(qp->s_next_psn++ & IPATH_PSN_MASK);
 393         /*
 394          * Qkeys with the high order bit set mean use the
 395          * qkey from the QP context instead of the WR (see 10.2.5).
 396          */
 397         ohdr->u.ud.deth[0] = cpu_to_be32((int)wqe->wr.wr.ud.remote_qkey < 0 ?
 398                                          qp->qkey : wqe->wr.wr.ud.remote_qkey);
 399         ohdr->u.ud.deth[1] = cpu_to_be32(qp->ibqp.qp_num);
 400
 401 done:
 402         ret = 1;
 403         goto unlock;
 404
 405 bail:
 406         qp->s_flags &= ~IPATH_S_BUSY;
 407 unlock:
 408         spin_unlock_irqrestore(&qp->s_lock, flags);
 409         return ret;
 410 }
 411
 412 /**
 413  * ipath_ud_rcv - receive an incoming UD packet
 414  * @dev: the device the packet came in on
 415  * @hdr: the packet header
 416  * @has_grh: true if the packet has a GRH
 417  * @data: the packet data
 418  * @tlen: the packet length
 419  * @qp: the QP the packet came on
 420  *
 421  * This is called from ipath_qp_rcv() to process an incoming UD packet
 422  * for the given QP.
 423  * Called at interrupt level.
 424  */
 425 void ipath_ud_rcv(struct ipath_ibdev *dev, struct ipath_ib_header *hdr,
 426                   int has_grh, void *data, u32 tlen, struct ipath_qp *qp)
 427 {
 428         struct ipath_other_headers *ohdr;
 429         int opcode;
 430         u32 hdrsize;
 431         u32 pad;
 432         struct ib_wc wc;
 433         u32 qkey;
 434         u32 src_qp;
 435         u16 dlid;
 436         int header_in_data;
 437
 438         /* Check for GRH */
 439         if (!has_grh) {
 440                 ohdr = &hdr->u.oth;
 441                 hdrsize = 8 + 12 + 8;   /* LRH + BTH + DETH */
 442                 qkey = be32_to_cpu(ohdr->u.ud.deth[0]);
 443                 src_qp = be32_to_cpu(ohdr->u.ud.deth[1]);
 444                 header_in_data = 0;
 445         } else {
 446                 ohdr = &hdr->u.l.oth;
 447                 hdrsize = 8 + 40 + 12 + 8; /* LRH + GRH + BTH + DETH */
 448                 /*
 449                  * The header with GRH is 68 bytes and the core driver sets
 450                  * the eager header buffer size to 56 bytes so the last 12
 451                  * bytes of the IB header is in the data buffer.
 452                  */
 453                 header_in_data = dev->dd->ipath_rcvhdrentsize == 16;
 454                 if (header_in_data) {
 455                         qkey = be32_to_cpu(((__be32 *) data)[1]);
 456                         src_qp = be32_to_cpu(((__be32 *) data)[2]);
 457                         data += 12;
 458                 } else {
 459                         qkey = be32_to_cpu(ohdr->u.ud.deth[0]);
 460                         src_qp = be32_to_cpu(ohdr->u.ud.deth[1]);
 461                 }
 462         }
 463         src_qp &= IPATH_QPN_MASK;
 464
 465         /*
 466          * Check that the permissive LID is only used on QP0
 467          * and the QKEY matches (see 9.6.1.4.1 and 9.6.1.5.1).
 468          */
 469         if (qp->ibqp.qp_num) {
 470                 if (unlikely(hdr->lrh[1] == IB_LID_PERMISSIVE ||
 471                              hdr->lrh[3] == IB_LID_PERMISSIVE)) {
 472                         dev->n_pkt_drops++;
 473                         goto bail;
 474                 }
 475                 if (unlikely(qkey != qp->qkey)) {
 476                         /* XXX OK to lose a count once in a while. */
 477                         dev->qkey_violations++;
 478                         dev->n_pkt_drops++;
 479                         goto bail;
 480                 }
 481         } else if (hdr->lrh[1] == IB_LID_PERMISSIVE ||
 482                    hdr->lrh[3] == IB_LID_PERMISSIVE) {
 483                 struct ib_smp *smp = (struct ib_smp *) data;
 484
 485                 if (smp->mgmt_class != IB_MGMT_CLASS_SUBN_DIRECTED_ROUTE) {
 486                         dev->n_pkt_drops++;
 487                         goto bail;
 488                 }
 489         }
 490
 491         /*
 492          * The opcode is in the low byte when its in network order
 493          * (top byte when in host order).
 494          */
 495         opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
 496         if (qp->ibqp.qp_num > 1 &&
 497             opcode == IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE) {
 498                 if (header_in_data) {
 499                         wc.ex.imm_data = *(__be32 *) data;
 500                         data += sizeof(__be32);
 501                 } else
 502                         wc.ex.imm_data = ohdr->u.ud.imm_data;
 503                 wc.wc_flags = IB_WC_WITH_IMM;
 504                 hdrsize += sizeof(u32);
 505         } else if (opcode == IB_OPCODE_UD_SEND_ONLY) {
 506                 wc.ex.imm_data = 0;
 507                 wc.wc_flags = 0;
 508         } else {
 509                 dev->n_pkt_drops++;
 510                 goto bail;
 511         }
 512
 513         /* Get the number of bytes the message was padded by. */
 514         pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
 515         if (unlikely(tlen < (hdrsize + pad + 4))) {
 516                 /* Drop incomplete packets. */
 517                 dev->n_pkt_drops++;
 518                 goto bail;
 519         }
 520         tlen -= hdrsize + pad + 4;
 521
 522         /* Drop invalid MAD packets (see 13.5.3.1). */
 523         if (unlikely((qp->ibqp.qp_num == 0 &&
 524                       (tlen != 256 ||
 525                        (be16_to_cpu(hdr->lrh[0]) >> 12) != 15)) ||
 526                      (qp->ibqp.qp_num == 1 &&
 527                       (tlen != 256 ||
 528                        (be16_to_cpu(hdr->lrh[0]) >> 12) == 15)))) {
 529                 dev->n_pkt_drops++;
 530                 goto bail;
 531         }
 532
 533         /*
 534          * A GRH is expected to preceed the data even if not
 535          * present on the wire.
 536          */
 537         wc.byte_len = tlen + sizeof(struct ib_grh);
 538
 539         /*
 540          * Get the next work request entry to find where to put the data.
 541          */
 542         if (qp->r_flags & IPATH_R_REUSE_SGE)
 543                 qp->r_flags &= ~IPATH_R_REUSE_SGE;
 544         else if (!ipath_get_rwqe(qp, 0)) {
 545                 /*
 546                  * Count VL15 packets dropped due to no receive buffer.
 547                  * Otherwise, count them as buffer overruns since usually,
 548                  * the HW will be able to receive packets even if there are
 549                  * no QPs with posted receive buffers.
 550                  */
 551                 if (qp->ibqp.qp_num == 0)
 552                         dev->n_vl15_dropped++;
 553                 else
 554                         dev->rcv_errors++;
 555                 goto bail;
 556         }
 557         /* Silently drop packets which are too big. */
 558         if (wc.byte_len > qp->r_len) {
 559                 qp->r_flags |= IPATH_R_REUSE_SGE;
 560                 dev->n_pkt_drops++;
 561                 goto bail;
 562         }
 563         if (has_grh) {
 564                 ipath_copy_sge(&qp->r_sge, &hdr->u.l.grh,
 565                                sizeof(struct ib_grh));
 566                 wc.wc_flags |= IB_WC_GRH;
 567         } else
 568                 ipath_skip_sge(&qp->r_sge, sizeof(struct ib_grh));
 569         ipath_copy_sge(&qp->r_sge, data,
 570                        wc.byte_len - sizeof(struct ib_grh));
 571         if (!test_and_clear_bit(IPATH_R_WRID_VALID, &qp->r_aflags))
 572                 goto bail;
 573         wc.wr_id = qp->r_wr_id;
 574         wc.status = IB_WC_SUCCESS;
 575         wc.opcode = IB_WC_RECV;
 576         wc.vendor_err = 0;
 577         wc.qp = &qp->ibqp;
 578         wc.src_qp = src_qp;
 579         /* XXX do we know which pkey matched? Only needed for GSI. */
 580         wc.pkey_index = 0;
 581         wc.slid = be16_to_cpu(hdr->lrh[3]);
 582         wc.sl = (be16_to_cpu(hdr->lrh[0]) >> 4) & 0xF;
 583         dlid = be16_to_cpu(hdr->lrh[1]);
 584         /*
 585          * Save the LMC lower bits if the destination LID is a unicast LID.
 586          */
 587         wc.dlid_path_bits = dlid >= IPATH_MULTICAST_LID_BASE ? 0 :
 588                 dlid & ((1 << dev->dd->ipath_lmc) - 1);
 589         wc.port_num = 1;
 590         /* Signal completion event if the solicited bit is set. */
 591         ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
 592                        (ohdr->bth[0] &
 593                         __constant_cpu_to_be32(1 << 23)) != 0);
 594
 595 bail:;
 596 }