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[linux-2.6.git] / 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
271         spin_lock_irqsave(&qp->s_lock, flags);
272
273         if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_NEXT_SEND_OK)) {
274                 if (!(ib_ipath_state_ops[qp->state] & IPATH_FLUSH_SEND))
275                         goto bail;
276                 /* We are in the error state, flush the work request. */
277                 if (qp->s_last == qp->s_head)
278                         goto bail;
279                 /* If DMAs are in progress, we can't flush immediately. */
280                 if (atomic_read(&qp->s_dma_busy)) {
281                         qp->s_flags |= IPATH_S_WAIT_DMA;
282                         goto bail;
283                 }
284                 wqe = get_swqe_ptr(qp, qp->s_last);
285                 ipath_send_complete(qp, wqe, IB_WC_WR_FLUSH_ERR);
286                 goto done;
287         }
288
289         if (qp->s_cur == qp->s_head)
290                 goto bail;
291
292         wqe = get_swqe_ptr(qp, qp->s_cur);
293         if (++qp->s_cur >= qp->s_size)
294                 qp->s_cur = 0;
295
296         /* Construct the header. */
297         ah_attr = &to_iah(wqe->wr.wr.ud.ah)->attr;
298         if (ah_attr->dlid >= IPATH_MULTICAST_LID_BASE) {
299                 if (ah_attr->dlid != IPATH_PERMISSIVE_LID)
300                         dev->n_multicast_xmit++;
301                 else
302                         dev->n_unicast_xmit++;
303         } else {
304                 dev->n_unicast_xmit++;
305                 lid = ah_attr->dlid & ~((1 << dev->dd->ipath_lmc) - 1);
306                 if (unlikely(lid == dev->dd->ipath_lid)) {
307                         /*
308                          * If DMAs are in progress, we can't generate
309                          * a completion for the loopback packet since
310                          * it would be out of order.
311                          * XXX Instead of waiting, we could queue a
312                          * zero length descriptor so we get a callback.
313                          */
314                         if (atomic_read(&qp->s_dma_busy)) {
315                                 qp->s_flags |= IPATH_S_WAIT_DMA;
316                                 goto bail;
317                         }
318                         spin_unlock_irqrestore(&qp->s_lock, flags);
319                         ipath_ud_loopback(qp, wqe);
320                         spin_lock_irqsave(&qp->s_lock, flags);
321                         ipath_send_complete(qp, wqe, IB_WC_SUCCESS);
322                         goto done;
323                 }
324         }
325
326         extra_bytes = -wqe->length & 3;
327         nwords = (wqe->length + extra_bytes) >> 2;
328
329         /* header size in 32-bit words LRH+BTH+DETH = (8+12+8)/4. */
330         qp->s_hdrwords = 7;
331         qp->s_cur_size = wqe->length;
332         qp->s_cur_sge = &qp->s_sge;
333         qp->s_dmult = ah_attr->static_rate;
334         qp->s_wqe = wqe;
335         qp->s_sge.sge = wqe->sg_list[0];
336         qp->s_sge.sg_list = wqe->sg_list + 1;
337         qp->s_sge.num_sge = wqe->wr.num_sge;
338
339         if (ah_attr->ah_flags & IB_AH_GRH) {
340                 /* Header size in 32-bit words. */
341                 qp->s_hdrwords += ipath_make_grh(dev, &qp->s_hdr.u.l.grh,
342                                                  &ah_attr->grh,
343                                                  qp->s_hdrwords, nwords);
344                 lrh0 = IPATH_LRH_GRH;
345                 ohdr = &qp->s_hdr.u.l.oth;
346                 /*
347                  * Don't worry about sending to locally attached multicast
348                  * QPs.  It is unspecified by the spec. what happens.
349                  */
350         } else {
351                 /* Header size in 32-bit words. */
352                 lrh0 = IPATH_LRH_BTH;
353                 ohdr = &qp->s_hdr.u.oth;
354         }
355         if (wqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
356                 qp->s_hdrwords++;
357                 ohdr->u.ud.imm_data = wqe->wr.ex.imm_data;
358                 bth0 = IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE << 24;
359         } else
360                 bth0 = IB_OPCODE_UD_SEND_ONLY << 24;
361         lrh0 |= ah_attr->sl << 4;
362         if (qp->ibqp.qp_type == IB_QPT_SMI)
363                 lrh0 |= 0xF000; /* Set VL (see ch. 13.5.3.1) */
364         qp->s_hdr.lrh[0] = cpu_to_be16(lrh0);
365         qp->s_hdr.lrh[1] = cpu_to_be16(ah_attr->dlid);  /* DEST LID */
366         qp->s_hdr.lrh[2] = cpu_to_be16(qp->s_hdrwords + nwords +
367                                            SIZE_OF_CRC);
368         lid = dev->dd->ipath_lid;
369         if (lid) {
370                 lid |= ah_attr->src_path_bits &
371                         ((1 << dev->dd->ipath_lmc) - 1);
372                 qp->s_hdr.lrh[3] = cpu_to_be16(lid);
373         } else
374                 qp->s_hdr.lrh[3] = IB_LID_PERMISSIVE;
375         if (wqe->wr.send_flags & IB_SEND_SOLICITED)
376                 bth0 |= 1 << 23;
377         bth0 |= extra_bytes << 20;
378         bth0 |= qp->ibqp.qp_type == IB_QPT_SMI ? IPATH_DEFAULT_P_KEY :
379                 ipath_get_pkey(dev->dd, qp->s_pkey_index);
380         ohdr->bth[0] = cpu_to_be32(bth0);
381         /*
382          * Use the multicast QP if the destination LID is a multicast LID.
383          */
384         ohdr->bth[1] = ah_attr->dlid >= IPATH_MULTICAST_LID_BASE &&
385                 ah_attr->dlid != IPATH_PERMISSIVE_LID ?
386                 __constant_cpu_to_be32(IPATH_MULTICAST_QPN) :
387                 cpu_to_be32(wqe->wr.wr.ud.remote_qpn);
388         ohdr->bth[2] = cpu_to_be32(qp->s_next_psn++ & IPATH_PSN_MASK);
389         /*
390          * Qkeys with the high order bit set mean use the
391          * qkey from the QP context instead of the WR (see 10.2.5).
392          */
393         ohdr->u.ud.deth[0] = cpu_to_be32((int)wqe->wr.wr.ud.remote_qkey < 0 ?
394                                          qp->qkey : wqe->wr.wr.ud.remote_qkey);
395         ohdr->u.ud.deth[1] = cpu_to_be32(qp->ibqp.qp_num);
396
397 done:
398         ret = 1;
399         goto unlock;
400
401 bail:
402         qp->s_flags &= ~IPATH_S_BUSY;
403 unlock:
404         spin_unlock_irqrestore(&qp->s_lock, flags);
405         return ret;
406 }
407
408 /**
409  * ipath_ud_rcv - receive an incoming UD packet
410  * @dev: the device the packet came in on
411  * @hdr: the packet header
412  * @has_grh: true if the packet has a GRH
413  * @data: the packet data
414  * @tlen: the packet length
415  * @qp: the QP the packet came on
416  *
417  * This is called from ipath_qp_rcv() to process an incoming UD packet
418  * for the given QP.
419  * Called at interrupt level.
420  */
421 void ipath_ud_rcv(struct ipath_ibdev *dev, struct ipath_ib_header *hdr,
422                   int has_grh, void *data, u32 tlen, struct ipath_qp *qp)
423 {
424         struct ipath_other_headers *ohdr;
425         int opcode;
426         u32 hdrsize;
427         u32 pad;
428         struct ib_wc wc;
429         u32 qkey;
430         u32 src_qp;
431         u16 dlid;
432         int header_in_data;
433
434         /* Check for GRH */
435         if (!has_grh) {
436                 ohdr = &hdr->u.oth;
437                 hdrsize = 8 + 12 + 8;   /* LRH + BTH + DETH */
438                 qkey = be32_to_cpu(ohdr->u.ud.deth[0]);
439                 src_qp = be32_to_cpu(ohdr->u.ud.deth[1]);
440                 header_in_data = 0;
441         } else {
442                 ohdr = &hdr->u.l.oth;
443                 hdrsize = 8 + 40 + 12 + 8; /* LRH + GRH + BTH + DETH */
444                 /*
445                  * The header with GRH is 68 bytes and the core driver sets
446                  * the eager header buffer size to 56 bytes so the last 12
447                  * bytes of the IB header is in the data buffer.
448                  */
449                 header_in_data = dev->dd->ipath_rcvhdrentsize == 16;
450                 if (header_in_data) {
451                         qkey = be32_to_cpu(((__be32 *) data)[1]);
452                         src_qp = be32_to_cpu(((__be32 *) data)[2]);
453                         data += 12;
454                 } else {
455                         qkey = be32_to_cpu(ohdr->u.ud.deth[0]);
456                         src_qp = be32_to_cpu(ohdr->u.ud.deth[1]);
457                 }
458         }
459         src_qp &= IPATH_QPN_MASK;
460
461         /*
462          * Check that the permissive LID is only used on QP0
463          * and the QKEY matches (see 9.6.1.4.1 and 9.6.1.5.1).
464          */
465         if (qp->ibqp.qp_num) {
466                 if (unlikely(hdr->lrh[1] == IB_LID_PERMISSIVE ||
467                              hdr->lrh[3] == IB_LID_PERMISSIVE)) {
468                         dev->n_pkt_drops++;
469                         goto bail;
470                 }
471                 if (unlikely(qkey != qp->qkey)) {
472                         /* XXX OK to lose a count once in a while. */
473                         dev->qkey_violations++;
474                         dev->n_pkt_drops++;
475                         goto bail;
476                 }
477         } else if (hdr->lrh[1] == IB_LID_PERMISSIVE ||
478                    hdr->lrh[3] == IB_LID_PERMISSIVE) {
479                 struct ib_smp *smp = (struct ib_smp *) data;
480
481                 if (smp->mgmt_class != IB_MGMT_CLASS_SUBN_DIRECTED_ROUTE) {
482                         dev->n_pkt_drops++;
483                         goto bail;
484                 }
485         }
486
487         /*
488          * The opcode is in the low byte when its in network order
489          * (top byte when in host order).
490          */
491         opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
492         if (qp->ibqp.qp_num > 1 &&
493             opcode == IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE) {
494                 if (header_in_data) {
495                         wc.ex.imm_data = *(__be32 *) data;
496                         data += sizeof(__be32);
497                 } else
498                         wc.ex.imm_data = ohdr->u.ud.imm_data;
499                 wc.wc_flags = IB_WC_WITH_IMM;
500                 hdrsize += sizeof(u32);
501         } else if (opcode == IB_OPCODE_UD_SEND_ONLY) {
502                 wc.ex.imm_data = 0;
503                 wc.wc_flags = 0;
504         } else {
505                 dev->n_pkt_drops++;
506                 goto bail;
507         }
508
509         /* Get the number of bytes the message was padded by. */
510         pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
511         if (unlikely(tlen < (hdrsize + pad + 4))) {
512                 /* Drop incomplete packets. */
513                 dev->n_pkt_drops++;
514                 goto bail;
515         }
516         tlen -= hdrsize + pad + 4;
517
518         /* Drop invalid MAD packets (see 13.5.3.1). */
519         if (unlikely((qp->ibqp.qp_num == 0 &&
520                       (tlen != 256 ||
521                        (be16_to_cpu(hdr->lrh[0]) >> 12) != 15)) ||
522                      (qp->ibqp.qp_num == 1 &&
523                       (tlen != 256 ||
524                        (be16_to_cpu(hdr->lrh[0]) >> 12) == 15)))) {
525                 dev->n_pkt_drops++;
526                 goto bail;
527         }
528
529         /*
530          * A GRH is expected to preceed the data even if not
531          * present on the wire.
532          */
533         wc.byte_len = tlen + sizeof(struct ib_grh);
534
535         /*
536          * Get the next work request entry to find where to put the data.
537          */
538         if (qp->r_flags & IPATH_R_REUSE_SGE)
539                 qp->r_flags &= ~IPATH_R_REUSE_SGE;
540         else if (!ipath_get_rwqe(qp, 0)) {
541                 /*
542                  * Count VL15 packets dropped due to no receive buffer.
543                  * Otherwise, count them as buffer overruns since usually,
544                  * the HW will be able to receive packets even if there are
545                  * no QPs with posted receive buffers.
546                  */
547                 if (qp->ibqp.qp_num == 0)
548                         dev->n_vl15_dropped++;
549                 else
550                         dev->rcv_errors++;
551                 goto bail;
552         }
553         /* Silently drop packets which are too big. */
554         if (wc.byte_len > qp->r_len) {
555                 qp->r_flags |= IPATH_R_REUSE_SGE;
556                 dev->n_pkt_drops++;
557                 goto bail;
558         }
559         if (has_grh) {
560                 ipath_copy_sge(&qp->r_sge, &hdr->u.l.grh,
561                                sizeof(struct ib_grh));
562                 wc.wc_flags |= IB_WC_GRH;
563         } else
564                 ipath_skip_sge(&qp->r_sge, sizeof(struct ib_grh));
565         ipath_copy_sge(&qp->r_sge, data,
566                        wc.byte_len - sizeof(struct ib_grh));
567         if (!test_and_clear_bit(IPATH_R_WRID_VALID, &qp->r_aflags))
568                 goto bail;
569         wc.wr_id = qp->r_wr_id;
570         wc.status = IB_WC_SUCCESS;
571         wc.opcode = IB_WC_RECV;
572         wc.vendor_err = 0;
573         wc.qp = &qp->ibqp;
574         wc.src_qp = src_qp;
575         /* XXX do we know which pkey matched? Only needed for GSI. */
576         wc.pkey_index = 0;
577         wc.slid = be16_to_cpu(hdr->lrh[3]);
578         wc.sl = (be16_to_cpu(hdr->lrh[0]) >> 4) & 0xF;
579         dlid = be16_to_cpu(hdr->lrh[1]);
580         /*
581          * Save the LMC lower bits if the destination LID is a unicast LID.
582          */
583         wc.dlid_path_bits = dlid >= IPATH_MULTICAST_LID_BASE ? 0 :
584                 dlid & ((1 << dev->dd->ipath_lmc) - 1);
585         wc.port_num = 1;
586         /* Signal completion event if the solicited bit is set. */
587         ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
588                        (ohdr->bth[0] &
589                         __constant_cpu_to_be32(1 << 23)) != 0);
590
591 bail:;
592 }