drivers/infiniband/hw/ipath/ipath_ud.c

   1 /*
   2  * Copyright (c) 2006 QLogic, Inc. 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 static int init_sge(struct ipath_qp *qp, struct ipath_rwqe *wqe,
  40                     u32 *lengthp, struct ipath_sge_state *ss)
  41 {
  42         struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
  43         int user = to_ipd(qp->ibqp.pd)->user;
  44         int i, j, ret;
  45         struct ib_wc wc;
  46
  47         *lengthp = 0;
  48         for (i = j = 0; i < wqe->num_sge; i++) {
  49                 if (wqe->sg_list[i].length == 0)
  50                         continue;
  51                 /* Check LKEY */
  52                 if ((user && wqe->sg_list[i].lkey == 0) ||
  53                     !ipath_lkey_ok(&dev->lk_table,
  54                                    j ? &ss->sg_list[j - 1] : &ss->sge,
  55                                    &wqe->sg_list[i], IB_ACCESS_LOCAL_WRITE))
  56                         goto bad_lkey;
  57                 *lengthp += wqe->sg_list[i].length;
  58                 j++;
  59         }
  60         ss->num_sge = j;
  61         ret = 1;
  62         goto bail;
  63
  64 bad_lkey:
  65         wc.wr_id = wqe->wr_id;
  66         wc.status = IB_WC_LOC_PROT_ERR;
  67         wc.opcode = IB_WC_RECV;
  68         wc.vendor_err = 0;
  69         wc.byte_len = 0;
  70         wc.imm_data = 0;
  71         wc.qp_num = qp->ibqp.qp_num;
  72         wc.src_qp = 0;
  73         wc.wc_flags = 0;
  74         wc.pkey_index = 0;
  75         wc.slid = 0;
  76         wc.sl = 0;
  77         wc.dlid_path_bits = 0;
  78         wc.port_num = 0;
  79         /* Signal solicited completion event. */
  80         ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc, 1);
  81         ret = 0;
  82 bail:
  83         return ret;
  84 }
  85
  86 /**
  87  * ipath_ud_loopback - handle send on loopback QPs
  88  * @sqp: the QP
  89  * @ss: the SGE state
  90  * @length: the length of the data to send
  91  * @wr: the work request
  92  * @wc: the work completion entry
  93  *
  94  * This is called from ipath_post_ud_send() to forward a WQE addressed
  95  * to the same HCA.
  96  * Note that the receive interrupt handler may be calling ipath_ud_rcv()
  97  * while this is being called.
  98  */
  99 static void ipath_ud_loopback(struct ipath_qp *sqp,
 100                               struct ipath_sge_state *ss,
 101                               u32 length, struct ib_send_wr *wr,
 102                               struct ib_wc *wc)
 103 {
 104         struct ipath_ibdev *dev = to_idev(sqp->ibqp.device);
 105         struct ipath_qp *qp;
 106         struct ib_ah_attr *ah_attr;
 107         unsigned long flags;
 108         struct ipath_rq *rq;
 109         struct ipath_srq *srq;
 110         struct ipath_sge_state rsge;
 111         struct ipath_sge *sge;
 112         struct ipath_rwq *wq;
 113         struct ipath_rwqe *wqe;
 114         void (*handler)(struct ib_event *, void *);
 115         u32 tail;
 116         u32 rlen;
 117
 118         qp = ipath_lookup_qpn(&dev->qp_table, wr->wr.ud.remote_qpn);
 119         if (!qp)
 120                 return;
 121
 122         /*
 123          * Check that the qkey matches (except for QP0, see 9.6.1.4.1).
 124          * Qkeys with the high order bit set mean use the
 125          * qkey from the QP context instead of the WR (see 10.2.5).
 126          */
 127         if (unlikely(qp->ibqp.qp_num &&
 128                      ((int) wr->wr.ud.remote_qkey < 0
 129                       ? qp->qkey : wr->wr.ud.remote_qkey) != qp->qkey)) {
 130                 /* XXX OK to lose a count once in a while. */
 131                 dev->qkey_violations++;
 132                 dev->n_pkt_drops++;
 133                 goto done;
 134         }
 135
 136         /*
 137          * A GRH is expected to preceed the data even if not
 138          * present on the wire.
 139          */
 140         wc->byte_len = length + sizeof(struct ib_grh);
 141
 142         if (wr->opcode == IB_WR_SEND_WITH_IMM) {
 143                 wc->wc_flags = IB_WC_WITH_IMM;
 144                 wc->imm_data = wr->imm_data;
 145         } else {
 146                 wc->wc_flags = 0;
 147                 wc->imm_data = 0;
 148         }
 149
 150         if (wr->num_sge > 1) {
 151                 rsge.sg_list = kmalloc((wr->num_sge - 1) *
 152                                         sizeof(struct ipath_sge),
 153                                        GFP_ATOMIC);
 154         } else
 155                 rsge.sg_list = NULL;
 156
 157         /*
 158          * Get the next work request entry to find where to put the data.
 159          * Note that it is safe to drop the lock after changing rq->tail
 160          * since ipath_post_receive() won't fill the empty slot.
 161          */
 162         if (qp->ibqp.srq) {
 163                 srq = to_isrq(qp->ibqp.srq);
 164                 handler = srq->ibsrq.event_handler;
 165                 rq = &srq->rq;
 166         } else {
 167                 srq = NULL;
 168                 handler = NULL;
 169                 rq = &qp->r_rq;
 170         }
 171
 172         spin_lock_irqsave(&rq->lock, flags);
 173         wq = rq->wq;
 174         tail = wq->tail;
 175         while (1) {
 176                 if (unlikely(tail == wq->head)) {
 177                         spin_unlock_irqrestore(&rq->lock, flags);
 178                         dev->n_pkt_drops++;
 179                         goto bail_sge;
 180                 }
 181                 wqe = get_rwqe_ptr(rq, tail);
 182                 if (++tail >= rq->size)
 183                         tail = 0;
 184                 if (init_sge(qp, wqe, &rlen, &rsge))
 185                         break;
 186                 wq->tail = tail;
 187         }
 188         /* Silently drop packets which are too big. */
 189         if (wc->byte_len > rlen) {
 190                 spin_unlock_irqrestore(&rq->lock, flags);
 191                 dev->n_pkt_drops++;
 192                 goto bail_sge;
 193         }
 194         wq->tail = tail;
 195         wc->wr_id = wqe->wr_id;
 196         if (handler) {
 197                 u32 n;
 198
 199                 /*
 200                  * validate head pointer value and compute
 201                  * the number of remaining WQEs.
 202                  */
 203                 n = wq->head;
 204                 if (n >= rq->size)
 205                         n = 0;
 206                 if (n < tail)
 207                         n += rq->size - tail;
 208                 else
 209                         n -= tail;
 210                 if (n < srq->limit) {
 211                         struct ib_event ev;
 212
 213                         srq->limit = 0;
 214                         spin_unlock_irqrestore(&rq->lock, flags);
 215                         ev.device = qp->ibqp.device;
 216                         ev.element.srq = qp->ibqp.srq;
 217                         ev.event = IB_EVENT_SRQ_LIMIT_REACHED;
 218                         handler(&ev, srq->ibsrq.srq_context);
 219                 } else
 220                         spin_unlock_irqrestore(&rq->lock, flags);
 221         } else
 222                 spin_unlock_irqrestore(&rq->lock, flags);
 223
 224         ah_attr = &to_iah(wr->wr.ud.ah)->attr;
 225         if (ah_attr->ah_flags & IB_AH_GRH) {
 226                 ipath_copy_sge(&rsge, &ah_attr->grh, sizeof(struct ib_grh));
 227                 wc->wc_flags |= IB_WC_GRH;
 228         } else
 229                 ipath_skip_sge(&rsge, sizeof(struct ib_grh));
 230         sge = &ss->sge;
 231         while (length) {
 232                 u32 len = sge->length;
 233
 234                 if (len > length)
 235                         len = length;
 236                 BUG_ON(len == 0);
 237                 ipath_copy_sge(&rsge, sge->vaddr, len);
 238                 sge->vaddr += len;
 239                 sge->length -= len;
 240                 sge->sge_length -= len;
 241                 if (sge->sge_length == 0) {
 242                         if (--ss->num_sge)
 243                                 *sge = *ss->sg_list++;
 244                 } else if (sge->length == 0 && sge->mr != NULL) {
 245                         if (++sge->n >= IPATH_SEGSZ) {
 246                                 if (++sge->m >= sge->mr->mapsz)
 247                                         break;
 248                                 sge->n = 0;
 249                         }
 250                         sge->vaddr =
 251                                 sge->mr->map[sge->m]->segs[sge->n].vaddr;
 252                         sge->length =
 253                                 sge->mr->map[sge->m]->segs[sge->n].length;
 254                 }
 255                 length -= len;
 256         }
 257         wc->status = IB_WC_SUCCESS;
 258         wc->opcode = IB_WC_RECV;
 259         wc->vendor_err = 0;
 260         wc->qp_num = qp->ibqp.qp_num;
 261         wc->src_qp = sqp->ibqp.qp_num;
 262         /* XXX do we know which pkey matched? Only needed for GSI. */
 263         wc->pkey_index = 0;
 264         wc->slid = dev->dd->ipath_lid |
 265                 (ah_attr->src_path_bits &
 266                  ((1 << (dev->mkeyprot_resv_lmc & 7)) - 1));
 267         wc->sl = ah_attr->sl;
 268         wc->dlid_path_bits =
 269                 ah_attr->dlid & ((1 << (dev->mkeyprot_resv_lmc & 7)) - 1);
 270         /* Signal completion event if the solicited bit is set. */
 271         ipath_cq_enter(to_icq(qp->ibqp.recv_cq), wc,
 272                        wr->send_flags & IB_SEND_SOLICITED);
 273
 274 bail_sge:
 275         kfree(rsge.sg_list);
 276 done:
 277         if (atomic_dec_and_test(&qp->refcount))
 278                 wake_up(&qp->wait);
 279 }
 280
 281 /**
 282  * ipath_post_ud_send - post a UD send on QP
 283  * @qp: the QP
 284  * @wr: the work request
 285  *
 286  * Note that we actually send the data as it is posted instead of putting
 287  * the request into a ring buffer.  If we wanted to use a ring buffer,
 288  * we would need to save a reference to the destination address in the SWQE.
 289  */
 290 int ipath_post_ud_send(struct ipath_qp *qp, struct ib_send_wr *wr)
 291 {
 292         struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
 293         struct ipath_other_headers *ohdr;
 294         struct ib_ah_attr *ah_attr;
 295         struct ipath_sge_state ss;
 296         struct ipath_sge *sg_list;
 297         struct ib_wc wc;
 298         u32 hwords;
 299         u32 nwords;
 300         u32 len;
 301         u32 extra_bytes;
 302         u32 bth0;
 303         u16 lrh0;
 304         u16 lid;
 305         int i;
 306         int ret;
 307
 308         if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_SEND_OK)) {
 309                 ret = 0;
 310                 goto bail;
 311         }
 312
 313         /* IB spec says that num_sge == 0 is OK. */
 314         if (wr->num_sge > qp->s_max_sge) {
 315                 ret = -EINVAL;
 316                 goto bail;
 317         }
 318
 319         if (wr->num_sge > 1) {
 320                 sg_list = kmalloc((qp->s_max_sge - 1) * sizeof(*sg_list),
 321                                   GFP_ATOMIC);
 322                 if (!sg_list) {
 323                         ret = -ENOMEM;
 324                         goto bail;
 325                 }
 326         } else
 327                 sg_list = NULL;
 328
 329         /* Check the buffer to send. */
 330         ss.sg_list = sg_list;
 331         ss.sge.mr = NULL;
 332         ss.sge.vaddr = NULL;
 333         ss.sge.length = 0;
 334         ss.sge.sge_length = 0;
 335         ss.num_sge = 0;
 336         len = 0;
 337         for (i = 0; i < wr->num_sge; i++) {
 338                 /* Check LKEY */
 339                 if (to_ipd(qp->ibqp.pd)->user && wr->sg_list[i].lkey == 0) {
 340                         ret = -EINVAL;
 341                         goto bail;
 342                 }
 343
 344                 if (wr->sg_list[i].length == 0)
 345                         continue;
 346                 if (!ipath_lkey_ok(&dev->lk_table, ss.num_sge ?
 347                                    sg_list + ss.num_sge - 1 : &ss.sge,
 348                                    &wr->sg_list[i], 0)) {
 349                         ret = -EINVAL;
 350                         goto bail;
 351                 }
 352                 len += wr->sg_list[i].length;
 353                 ss.num_sge++;
 354         }
 355         /* Check for invalid packet size. */
 356         if (len > dev->dd->ipath_ibmtu) {
 357                 ret = -EINVAL;
 358                 goto bail;
 359         }
 360         extra_bytes = (4 - len) & 3;
 361         nwords = (len + extra_bytes) >> 2;
 362
 363         /* Construct the header. */
 364         ah_attr = &to_iah(wr->wr.ud.ah)->attr;
 365         if (ah_attr->dlid == 0) {
 366                 ret = -EINVAL;
 367                 goto bail;
 368         }
 369         if (ah_attr->dlid >= IPATH_MULTICAST_LID_BASE) {
 370                 if (ah_attr->dlid != IPATH_PERMISSIVE_LID)
 371                         dev->n_multicast_xmit++;
 372                 else
 373                         dev->n_unicast_xmit++;
 374         } else {
 375                 dev->n_unicast_xmit++;
 376                 lid = ah_attr->dlid &
 377                         ~((1 << (dev->mkeyprot_resv_lmc & 7)) - 1);
 378                 if (unlikely(lid == dev->dd->ipath_lid)) {
 379                         /*
 380                          * Pass in an uninitialized ib_wc to save stack
 381                          * space.
 382                          */
 383                         ipath_ud_loopback(qp, &ss, len, wr, &wc);
 384                         goto done;
 385                 }
 386         }
 387         if (ah_attr->ah_flags & IB_AH_GRH) {
 388                 /* Header size in 32-bit words. */
 389                 hwords = 17;
 390                 lrh0 = IPATH_LRH_GRH;
 391                 ohdr = &qp->s_hdr.u.l.oth;
 392                 qp->s_hdr.u.l.grh.version_tclass_flow =
 393                         cpu_to_be32((6 << 28) |
 394                                     (ah_attr->grh.traffic_class << 20) |
 395                                     ah_attr->grh.flow_label);
 396                 qp->s_hdr.u.l.grh.paylen =
 397                         cpu_to_be16(((wr->opcode ==
 398                                       IB_WR_SEND_WITH_IMM ? 6 : 5) +
 399                                      nwords + SIZE_OF_CRC) << 2);
 400                 /* next_hdr is defined by C8-7 in ch. 8.4.1 */
 401                 qp->s_hdr.u.l.grh.next_hdr = 0x1B;
 402                 qp->s_hdr.u.l.grh.hop_limit = ah_attr->grh.hop_limit;
 403                 /* The SGID is 32-bit aligned. */
 404                 qp->s_hdr.u.l.grh.sgid.global.subnet_prefix =
 405                         dev->gid_prefix;
 406                 qp->s_hdr.u.l.grh.sgid.global.interface_id =
 407                         dev->dd->ipath_guid;
 408                 qp->s_hdr.u.l.grh.dgid = ah_attr->grh.dgid;
 409                 /*
 410                  * Don't worry about sending to locally attached multicast
 411                  * QPs.  It is unspecified by the spec. what happens.
 412                  */
 413         } else {
 414                 /* Header size in 32-bit words. */
 415                 hwords = 7;
 416                 lrh0 = IPATH_LRH_BTH;
 417                 ohdr = &qp->s_hdr.u.oth;
 418         }
 419         if (wr->opcode == IB_WR_SEND_WITH_IMM) {
 420                 ohdr->u.ud.imm_data = wr->imm_data;
 421                 wc.imm_data = wr->imm_data;
 422                 hwords += 1;
 423                 bth0 = IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE << 24;
 424         } else if (wr->opcode == IB_WR_SEND) {
 425                 wc.imm_data = 0;
 426                 bth0 = IB_OPCODE_UD_SEND_ONLY << 24;
 427         } else {
 428                 ret = -EINVAL;
 429                 goto bail;
 430         }
 431         lrh0 |= ah_attr->sl << 4;
 432         if (qp->ibqp.qp_type == IB_QPT_SMI)
 433                 lrh0 |= 0xF000; /* Set VL (see ch. 13.5.3.1) */
 434         qp->s_hdr.lrh[0] = cpu_to_be16(lrh0);
 435         qp->s_hdr.lrh[1] = cpu_to_be16(ah_attr->dlid);  /* DEST LID */
 436         qp->s_hdr.lrh[2] = cpu_to_be16(hwords + nwords + SIZE_OF_CRC);
 437         lid = dev->dd->ipath_lid;
 438         if (lid) {
 439                 lid |= ah_attr->src_path_bits &
 440                         ((1 << (dev->mkeyprot_resv_lmc & 7)) - 1);
 441                 qp->s_hdr.lrh[3] = cpu_to_be16(lid);
 442         } else
 443                 qp->s_hdr.lrh[3] = IB_LID_PERMISSIVE;
 444         if (wr->send_flags & IB_SEND_SOLICITED)
 445                 bth0 |= 1 << 23;
 446         bth0 |= extra_bytes << 20;
 447         bth0 |= qp->ibqp.qp_type == IB_QPT_SMI ? IPATH_DEFAULT_P_KEY :
 448                 ipath_get_pkey(dev->dd, qp->s_pkey_index);
 449         ohdr->bth[0] = cpu_to_be32(bth0);
 450         /*
 451          * Use the multicast QP if the destination LID is a multicast LID.
 452          */
 453         ohdr->bth[1] = ah_attr->dlid >= IPATH_MULTICAST_LID_BASE &&
 454                 ah_attr->dlid != IPATH_PERMISSIVE_LID ?
 455                 __constant_cpu_to_be32(IPATH_MULTICAST_QPN) :
 456                 cpu_to_be32(wr->wr.ud.remote_qpn);
 457         /* XXX Could lose a PSN count but not worth locking */
 458         ohdr->bth[2] = cpu_to_be32(qp->s_next_psn++ & IPATH_PSN_MASK);
 459         /*
 460          * Qkeys with the high order bit set mean use the
 461          * qkey from the QP context instead of the WR (see 10.2.5).
 462          */
 463         ohdr->u.ud.deth[0] = cpu_to_be32((int)wr->wr.ud.remote_qkey < 0 ?
 464                                          qp->qkey : wr->wr.ud.remote_qkey);
 465         ohdr->u.ud.deth[1] = cpu_to_be32(qp->ibqp.qp_num);
 466         if (ipath_verbs_send(dev->dd, hwords, (u32 *) &qp->s_hdr,
 467                              len, &ss))
 468                 dev->n_no_piobuf++;
 469
 470 done:
 471         /* Queue the completion status entry. */
 472         if (!test_bit(IPATH_S_SIGNAL_REQ_WR, &qp->s_flags) ||
 473             (wr->send_flags & IB_SEND_SIGNALED)) {
 474                 wc.wr_id = wr->wr_id;
 475                 wc.status = IB_WC_SUCCESS;
 476                 wc.vendor_err = 0;
 477                 wc.opcode = IB_WC_SEND;
 478                 wc.byte_len = len;
 479                 wc.qp_num = qp->ibqp.qp_num;
 480                 wc.src_qp = 0;
 481                 wc.wc_flags = 0;
 482                 /* XXX initialize other fields? */
 483                 ipath_cq_enter(to_icq(qp->ibqp.send_cq), &wc, 0);
 484         }
 485         kfree(sg_list);
 486
 487         ret = 0;
 488
 489 bail:
 490         return ret;
 491 }
 492
 493 /**
 494  * ipath_ud_rcv - receive an incoming UD packet
 495  * @dev: the device the packet came in on
 496  * @hdr: the packet header
 497  * @has_grh: true if the packet has a GRH
 498  * @data: the packet data
 499  * @tlen: the packet length
 500  * @qp: the QP the packet came on
 501  *
 502  * This is called from ipath_qp_rcv() to process an incoming UD packet
 503  * for the given QP.
 504  * Called at interrupt level.
 505  */
 506 void ipath_ud_rcv(struct ipath_ibdev *dev, struct ipath_ib_header *hdr,
 507                   int has_grh, void *data, u32 tlen, struct ipath_qp *qp)
 508 {
 509         struct ipath_other_headers *ohdr;
 510         int opcode;
 511         u32 hdrsize;
 512         u32 pad;
 513         struct ib_wc wc;
 514         u32 qkey;
 515         u32 src_qp;
 516         u16 dlid;
 517         int header_in_data;
 518
 519         /* Check for GRH */
 520         if (!has_grh) {
 521                 ohdr = &hdr->u.oth;
 522                 hdrsize = 8 + 12 + 8;   /* LRH + BTH + DETH */
 523                 qkey = be32_to_cpu(ohdr->u.ud.deth[0]);
 524                 src_qp = be32_to_cpu(ohdr->u.ud.deth[1]);
 525                 header_in_data = 0;
 526         } else {
 527                 ohdr = &hdr->u.l.oth;
 528                 hdrsize = 8 + 40 + 12 + 8; /* LRH + GRH + BTH + DETH */
 529                 /*
 530                  * The header with GRH is 68 bytes and the core driver sets
 531                  * the eager header buffer size to 56 bytes so the last 12
 532                  * bytes of the IB header is in the data buffer.
 533                  */
 534                 header_in_data = dev->dd->ipath_rcvhdrentsize == 16;
 535                 if (header_in_data) {
 536                         qkey = be32_to_cpu(((__be32 *) data)[1]);
 537                         src_qp = be32_to_cpu(((__be32 *) data)[2]);
 538                         data += 12;
 539                 } else {
 540                         qkey = be32_to_cpu(ohdr->u.ud.deth[0]);
 541                         src_qp = be32_to_cpu(ohdr->u.ud.deth[1]);
 542                 }
 543         }
 544         src_qp &= IPATH_QPN_MASK;
 545
 546         /*
 547          * Check that the permissive LID is only used on QP0
 548          * and the QKEY matches (see 9.6.1.4.1 and 9.6.1.5.1).
 549          */
 550         if (qp->ibqp.qp_num) {
 551                 if (unlikely(hdr->lrh[1] == IB_LID_PERMISSIVE ||
 552                              hdr->lrh[3] == IB_LID_PERMISSIVE)) {
 553                         dev->n_pkt_drops++;
 554                         goto bail;
 555                 }
 556                 if (unlikely(qkey != qp->qkey)) {
 557                         /* XXX OK to lose a count once in a while. */
 558                         dev->qkey_violations++;
 559                         dev->n_pkt_drops++;
 560                         goto bail;
 561                 }
 562         } else if (hdr->lrh[1] == IB_LID_PERMISSIVE ||
 563                    hdr->lrh[3] == IB_LID_PERMISSIVE) {
 564                 struct ib_smp *smp = (struct ib_smp *) data;
 565
 566                 if (smp->mgmt_class != IB_MGMT_CLASS_SUBN_DIRECTED_ROUTE) {
 567                         dev->n_pkt_drops++;
 568                         goto bail;
 569                 }
 570         }
 571
 572         /* Get the number of bytes the message was padded by. */
 573         pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
 574         if (unlikely(tlen < (hdrsize + pad + 4))) {
 575                 /* Drop incomplete packets. */
 576                 dev->n_pkt_drops++;
 577                 goto bail;
 578         }
 579         tlen -= hdrsize + pad + 4;
 580
 581         /* Drop invalid MAD packets (see 13.5.3.1). */
 582         if (unlikely((qp->ibqp.qp_num == 0 &&
 583                       (tlen != 256 ||
 584                        (be16_to_cpu(hdr->lrh[0]) >> 12) != 15)) ||
 585                      (qp->ibqp.qp_num == 1 &&
 586                       (tlen != 256 ||
 587                        (be16_to_cpu(hdr->lrh[0]) >> 12) == 15)))) {
 588                 dev->n_pkt_drops++;
 589                 goto bail;
 590         }
 591
 592         /*
 593          * A GRH is expected to preceed the data even if not
 594          * present on the wire.
 595          */
 596         wc.byte_len = tlen + sizeof(struct ib_grh);
 597
 598         /*
 599          * The opcode is in the low byte when its in network order
 600          * (top byte when in host order).
 601          */
 602         opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
 603         if (qp->ibqp.qp_num > 1 &&
 604             opcode == IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE) {
 605                 if (header_in_data) {
 606                         wc.imm_data = *(__be32 *) data;
 607                         data += sizeof(__be32);
 608                 } else
 609                         wc.imm_data = ohdr->u.ud.imm_data;
 610                 wc.wc_flags = IB_WC_WITH_IMM;
 611                 hdrsize += sizeof(u32);
 612         } else if (opcode == IB_OPCODE_UD_SEND_ONLY) {
 613                 wc.imm_data = 0;
 614                 wc.wc_flags = 0;
 615         } else {
 616                 dev->n_pkt_drops++;
 617                 goto bail;
 618         }
 619
 620         /*
 621          * Get the next work request entry to find where to put the data.
 622          */
 623         if (qp->r_reuse_sge)
 624                 qp->r_reuse_sge = 0;
 625         else if (!ipath_get_rwqe(qp, 0)) {
 626                 /*
 627                  * Count VL15 packets dropped due to no receive buffer.
 628                  * Otherwise, count them as buffer overruns since usually,
 629                  * the HW will be able to receive packets even if there are
 630                  * no QPs with posted receive buffers.
 631                  */
 632                 if (qp->ibqp.qp_num == 0)
 633                         dev->n_vl15_dropped++;
 634                 else
 635                         dev->rcv_errors++;
 636                 goto bail;
 637         }
 638         /* Silently drop packets which are too big. */
 639         if (wc.byte_len > qp->r_len) {
 640                 qp->r_reuse_sge = 1;
 641                 dev->n_pkt_drops++;
 642                 goto bail;
 643         }
 644         if (has_grh) {
 645                 ipath_copy_sge(&qp->r_sge, &hdr->u.l.grh,
 646                                sizeof(struct ib_grh));
 647                 wc.wc_flags |= IB_WC_GRH;
 648         } else
 649                 ipath_skip_sge(&qp->r_sge, sizeof(struct ib_grh));
 650         ipath_copy_sge(&qp->r_sge, data,
 651                        wc.byte_len - sizeof(struct ib_grh));
 652         wc.wr_id = qp->r_wr_id;
 653         wc.status = IB_WC_SUCCESS;
 654         wc.opcode = IB_WC_RECV;
 655         wc.vendor_err = 0;
 656         wc.qp_num = qp->ibqp.qp_num;
 657         wc.src_qp = src_qp;
 658         /* XXX do we know which pkey matched? Only needed for GSI. */
 659         wc.pkey_index = 0;
 660         wc.slid = be16_to_cpu(hdr->lrh[3]);
 661         wc.sl = (be16_to_cpu(hdr->lrh[0]) >> 4) & 0xF;
 662         dlid = be16_to_cpu(hdr->lrh[1]);
 663         /*
 664          * Save the LMC lower bits if the destination LID is a unicast LID.
 665          */
 666         wc.dlid_path_bits = dlid >= IPATH_MULTICAST_LID_BASE ? 0 :
 667                 dlid & ((1 << (dev->mkeyprot_resv_lmc & 7)) - 1);
 668         /* Signal completion event if the solicited bit is set. */
 669         ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
 670                        (ohdr->bth[0] &
 671                         __constant_cpu_to_be32(1 << 23)) != 0);
 672
 673 bail:;
 674 }