summaryrefslogtreecommitdiff
path: root/drivers/infiniband/hw/qib/qib_ud.c
blob: 10d062561bd96f49617a754d26873353b39d78a4 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
/*
 * Copyright (c) 2006, 2007, 2008, 2009 QLogic Corporation. All rights reserved.
 * Copyright (c) 2005, 2006 PathScale, Inc. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <rdma/ib_smi.h>
#include <rdma/ib_verbs.h>

#include "qib.h"
#include "qib_mad.h"

/**
 * qib_ud_loopback - handle send on loopback QPs
 * @sqp: the sending QP
 * @swqe: the send work request
 *
 * This is called from qib_make_ud_req() to forward a WQE addressed
 * to the same HCA.
 * Note that the receive interrupt handler may be calling qib_ud_rcv()
 * while this is being called.
 */
static void qib_ud_loopback(struct rvt_qp *sqp, struct rvt_swqe *swqe)
{
	struct qib_ibport *ibp = to_iport(sqp->ibqp.device, sqp->port_num);
	struct qib_pportdata *ppd = ppd_from_ibp(ibp);
	struct qib_devdata *dd = ppd->dd;
	struct rvt_dev_info *rdi = &dd->verbs_dev.rdi;
	struct rvt_qp *qp;
	struct ib_ah_attr *ah_attr;
	unsigned long flags;
	struct rvt_sge_state ssge;
	struct rvt_sge *sge;
	struct ib_wc wc;
	u32 length;
	enum ib_qp_type sqptype, dqptype;

	rcu_read_lock();
	qp = rvt_lookup_qpn(rdi, &ibp->rvp, swqe->ud_wr.remote_qpn);
	if (!qp) {
		ibp->rvp.n_pkt_drops++;
		rcu_read_unlock();
		return;
	}

	sqptype = sqp->ibqp.qp_type == IB_QPT_GSI ?
			IB_QPT_UD : sqp->ibqp.qp_type;
	dqptype = qp->ibqp.qp_type == IB_QPT_GSI ?
			IB_QPT_UD : qp->ibqp.qp_type;

	if (dqptype != sqptype ||
	    !(ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK)) {
		ibp->rvp.n_pkt_drops++;
		goto drop;
	}

	ah_attr = &ibah_to_rvtah(swqe->ud_wr.ah)->attr;
	ppd = ppd_from_ibp(ibp);

	if (qp->ibqp.qp_num > 1) {
		u16 pkey1;
		u16 pkey2;
		u16 lid;

		pkey1 = qib_get_pkey(ibp, sqp->s_pkey_index);
		pkey2 = qib_get_pkey(ibp, qp->s_pkey_index);
		if (unlikely(!qib_pkey_ok(pkey1, pkey2))) {
			lid = ppd->lid | (ah_attr->src_path_bits &
					  ((1 << ppd->lmc) - 1));
			qib_bad_pqkey(ibp, IB_NOTICE_TRAP_BAD_PKEY, pkey1,
				      ah_attr->sl,
				      sqp->ibqp.qp_num, qp->ibqp.qp_num,
				      cpu_to_be16(lid),
				      cpu_to_be16(ah_attr->dlid));
			goto drop;
		}
	}

	/*
	 * Check that the qkey matches (except for QP0, see 9.6.1.4.1).
	 * Qkeys with the high order bit set mean use the
	 * qkey from the QP context instead of the WR (see 10.2.5).
	 */
	if (qp->ibqp.qp_num) {
		u32 qkey;

		qkey = (int)swqe->ud_wr.remote_qkey < 0 ?
			sqp->qkey : swqe->ud_wr.remote_qkey;
		if (unlikely(qkey != qp->qkey)) {
			u16 lid;

			lid = ppd->lid | (ah_attr->src_path_bits &
					  ((1 << ppd->lmc) - 1));
			qib_bad_pqkey(ibp, IB_NOTICE_TRAP_BAD_QKEY, qkey,
				      ah_attr->sl,
				      sqp->ibqp.qp_num, qp->ibqp.qp_num,
				      cpu_to_be16(lid),
				      cpu_to_be16(ah_attr->dlid));
			goto drop;
		}
	}

	/*
	 * A GRH is expected to precede the data even if not
	 * present on the wire.
	 */
	length = swqe->length;
	memset(&wc, 0, sizeof(wc));
	wc.byte_len = length + sizeof(struct ib_grh);

	if (swqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
		wc.wc_flags = IB_WC_WITH_IMM;
		wc.ex.imm_data = swqe->wr.ex.imm_data;
	}

	spin_lock_irqsave(&qp->r_lock, flags);

	/*
	 * Get the next work request entry to find where to put the data.
	 */
	if (qp->r_flags & RVT_R_REUSE_SGE)
		qp->r_flags &= ~RVT_R_REUSE_SGE;
	else {
		int ret;

		ret = qib_get_rwqe(qp, 0);
		if (ret < 0) {
			qib_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
			goto bail_unlock;
		}
		if (!ret) {
			if (qp->ibqp.qp_num == 0)
				ibp->rvp.n_vl15_dropped++;
			goto bail_unlock;
		}
	}
	/* Silently drop packets which are too big. */
	if (unlikely(wc.byte_len > qp->r_len)) {
		qp->r_flags |= RVT_R_REUSE_SGE;
		ibp->rvp.n_pkt_drops++;
		goto bail_unlock;
	}

	if (ah_attr->ah_flags & IB_AH_GRH) {
		struct ib_grh grh;
		struct ib_global_route grd = ah_attr->grh;

		qib_make_grh(ibp, &grh, &grd, 0, 0);
		qib_copy_sge(&qp->r_sge, &grh,
			     sizeof(grh), 1);
		wc.wc_flags |= IB_WC_GRH;
	} else
		qib_skip_sge(&qp->r_sge, sizeof(struct ib_grh), 1);
	ssge.sg_list = swqe->sg_list + 1;
	ssge.sge = *swqe->sg_list;
	ssge.num_sge = swqe->wr.num_sge;
	sge = &ssge.sge;
	while (length) {
		u32 len = sge->length;

		if (len > length)
			len = length;
		if (len > sge->sge_length)
			len = sge->sge_length;
		BUG_ON(len == 0);
		qib_copy_sge(&qp->r_sge, sge->vaddr, len, 1);
		sge->vaddr += len;
		sge->length -= len;
		sge->sge_length -= len;
		if (sge->sge_length == 0) {
			if (--ssge.num_sge)
				*sge = *ssge.sg_list++;
		} else if (sge->length == 0 && sge->mr->lkey) {
			if (++sge->n >= RVT_SEGSZ) {
				if (++sge->m >= sge->mr->mapsz)
					break;
				sge->n = 0;
			}
			sge->vaddr =
				sge->mr->map[sge->m]->segs[sge->n].vaddr;
			sge->length =
				sge->mr->map[sge->m]->segs[sge->n].length;
		}
		length -= len;
	}
	rvt_put_ss(&qp->r_sge);
	if (!test_and_clear_bit(RVT_R_WRID_VALID, &qp->r_aflags))
		goto bail_unlock;
	wc.wr_id = qp->r_wr_id;
	wc.status = IB_WC_SUCCESS;
	wc.opcode = IB_WC_RECV;
	wc.qp = &qp->ibqp;
	wc.src_qp = sqp->ibqp.qp_num;
	wc.pkey_index = qp->ibqp.qp_type == IB_QPT_GSI ?
		swqe->ud_wr.pkey_index : 0;
	wc.slid = ppd->lid | (ah_attr->src_path_bits & ((1 << ppd->lmc) - 1));
	wc.sl = ah_attr->sl;
	wc.dlid_path_bits = ah_attr->dlid & ((1 << ppd->lmc) - 1);
	wc.port_num = qp->port_num;
	/* Signal completion event if the solicited bit is set. */
	rvt_cq_enter(ibcq_to_rvtcq(qp->ibqp.recv_cq), &wc,
		     swqe->wr.send_flags & IB_SEND_SOLICITED);
	ibp->rvp.n_loop_pkts++;
bail_unlock:
	spin_unlock_irqrestore(&qp->r_lock, flags);
drop:
	rcu_read_unlock();
}

/**
 * qib_make_ud_req - construct a UD request packet
 * @qp: the QP
 *
 * Assumes the s_lock is held.
 *
 * Return 1 if constructed; otherwise, return 0.
 */
int qib_make_ud_req(struct rvt_qp *qp, unsigned long *flags)
{
	struct qib_qp_priv *priv = qp->priv;
	struct qib_other_headers *ohdr;
	struct ib_ah_attr *ah_attr;
	struct qib_pportdata *ppd;
	struct qib_ibport *ibp;
	struct rvt_swqe *wqe;
	u32 nwords;
	u32 extra_bytes;
	u32 bth0;
	u16 lrh0;
	u16 lid;
	int ret = 0;
	int next_cur;

	if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_NEXT_SEND_OK)) {
		if (!(ib_rvt_state_ops[qp->state] & RVT_FLUSH_SEND))
			goto bail;
		/* We are in the error state, flush the work request. */
		smp_read_barrier_depends(); /* see post_one_send */
		if (qp->s_last == ACCESS_ONCE(qp->s_head))
			goto bail;
		/* If DMAs are in progress, we can't flush immediately. */
		if (atomic_read(&priv->s_dma_busy)) {
			qp->s_flags |= RVT_S_WAIT_DMA;
			goto bail;
		}
		wqe = rvt_get_swqe_ptr(qp, qp->s_last);
		qib_send_complete(qp, wqe, IB_WC_WR_FLUSH_ERR);
		goto done;
	}

	/* see post_one_send() */
	smp_read_barrier_depends();
	if (qp->s_cur == ACCESS_ONCE(qp->s_head))
		goto bail;

	wqe = rvt_get_swqe_ptr(qp, qp->s_cur);
	next_cur = qp->s_cur + 1;
	if (next_cur >= qp->s_size)
		next_cur = 0;

	/* Construct the header. */
	ibp = to_iport(qp->ibqp.device, qp->port_num);
	ppd = ppd_from_ibp(ibp);
	ah_attr = &ibah_to_rvtah(wqe->ud_wr.ah)->attr;
	if (ah_attr->dlid >= be16_to_cpu(IB_MULTICAST_LID_BASE)) {
		if (ah_attr->dlid != be16_to_cpu(IB_LID_PERMISSIVE))
			this_cpu_inc(ibp->pmastats->n_multicast_xmit);
		else
			this_cpu_inc(ibp->pmastats->n_unicast_xmit);
	} else {
		this_cpu_inc(ibp->pmastats->n_unicast_xmit);
		lid = ah_attr->dlid & ~((1 << ppd->lmc) - 1);
		if (unlikely(lid == ppd->lid)) {
			unsigned long tflags = *flags;
			/*
			 * If DMAs are in progress, we can't generate
			 * a completion for the loopback packet since
			 * it would be out of order.
			 * XXX Instead of waiting, we could queue a
			 * zero length descriptor so we get a callback.
			 */
			if (atomic_read(&priv->s_dma_busy)) {
				qp->s_flags |= RVT_S_WAIT_DMA;
				goto bail;
			}
			qp->s_cur = next_cur;
			spin_unlock_irqrestore(&qp->s_lock, tflags);
			qib_ud_loopback(qp, wqe);
			spin_lock_irqsave(&qp->s_lock, tflags);
			*flags = tflags;
			qib_send_complete(qp, wqe, IB_WC_SUCCESS);
			goto done;
		}
	}

	qp->s_cur = next_cur;
	extra_bytes = -wqe->length & 3;
	nwords = (wqe->length + extra_bytes) >> 2;

	/* header size in 32-bit words LRH+BTH+DETH = (8+12+8)/4. */
	qp->s_hdrwords = 7;
	qp->s_cur_size = wqe->length;
	qp->s_cur_sge = &qp->s_sge;
	qp->s_srate = ah_attr->static_rate;
	qp->s_wqe = wqe;
	qp->s_sge.sge = wqe->sg_list[0];
	qp->s_sge.sg_list = wqe->sg_list + 1;
	qp->s_sge.num_sge = wqe->wr.num_sge;
	qp->s_sge.total_len = wqe->length;

	if (ah_attr->ah_flags & IB_AH_GRH) {
		/* Header size in 32-bit words. */
		qp->s_hdrwords += qib_make_grh(ibp, &priv->s_hdr->u.l.grh,
					       &ah_attr->grh,
					       qp->s_hdrwords, nwords);
		lrh0 = QIB_LRH_GRH;
		ohdr = &priv->s_hdr->u.l.oth;
		/*
		 * Don't worry about sending to locally attached multicast
		 * QPs.  It is unspecified by the spec. what happens.
		 */
	} else {
		/* Header size in 32-bit words. */
		lrh0 = QIB_LRH_BTH;
		ohdr = &priv->s_hdr->u.oth;
	}
	if (wqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
		qp->s_hdrwords++;
		ohdr->u.ud.imm_data = wqe->wr.ex.imm_data;
		bth0 = IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE << 24;
	} else
		bth0 = IB_OPCODE_UD_SEND_ONLY << 24;
	lrh0 |= ah_attr->sl << 4;
	if (qp->ibqp.qp_type == IB_QPT_SMI)
		lrh0 |= 0xF000; /* Set VL (see ch. 13.5.3.1) */
	else
		lrh0 |= ibp->sl_to_vl[ah_attr->sl] << 12;
	priv->s_hdr->lrh[0] = cpu_to_be16(lrh0);
	priv->s_hdr->lrh[1] = cpu_to_be16(ah_attr->dlid);  /* DEST LID */
	priv->s_hdr->lrh[2] =
			cpu_to_be16(qp->s_hdrwords + nwords + SIZE_OF_CRC);
	lid = ppd->lid;
	if (lid) {
		lid |= ah_attr->src_path_bits & ((1 << ppd->lmc) - 1);
		priv->s_hdr->lrh[3] = cpu_to_be16(lid);
	} else
		priv->s_hdr->lrh[3] = IB_LID_PERMISSIVE;
	if (wqe->wr.send_flags & IB_SEND_SOLICITED)
		bth0 |= IB_BTH_SOLICITED;
	bth0 |= extra_bytes << 20;
	bth0 |= qp->ibqp.qp_type == IB_QPT_SMI ? QIB_DEFAULT_P_KEY :
		qib_get_pkey(ibp, qp->ibqp.qp_type == IB_QPT_GSI ?
			     wqe->ud_wr.pkey_index : qp->s_pkey_index);
	ohdr->bth[0] = cpu_to_be32(bth0);
	/*
	 * Use the multicast QP if the destination LID is a multicast LID.
	 */
	ohdr->bth[1] = ah_attr->dlid >= be16_to_cpu(IB_MULTICAST_LID_BASE) &&
		ah_attr->dlid != be16_to_cpu(IB_LID_PERMISSIVE) ?
		cpu_to_be32(QIB_MULTICAST_QPN) :
		cpu_to_be32(wqe->ud_wr.remote_qpn);
	ohdr->bth[2] = cpu_to_be32(wqe->psn & QIB_PSN_MASK);
	/*
	 * Qkeys with the high order bit set mean use the
	 * qkey from the QP context instead of the WR (see 10.2.5).
	 */
	ohdr->u.ud.deth[0] = cpu_to_be32((int)wqe->ud_wr.remote_qkey < 0 ?
					 qp->qkey : wqe->ud_wr.remote_qkey);
	ohdr->u.ud.deth[1] = cpu_to_be32(qp->ibqp.qp_num);

done:
	return 1;
bail:
	qp->s_flags &= ~RVT_S_BUSY;
	return ret;
}

static unsigned qib_lookup_pkey(struct qib_ibport *ibp, u16 pkey)
{
	struct qib_pportdata *ppd = ppd_from_ibp(ibp);
	struct qib_devdata *dd = ppd->dd;
	unsigned ctxt = ppd->hw_pidx;
	unsigned i;

	pkey &= 0x7fff;	/* remove limited/full membership bit */

	for (i = 0; i < ARRAY_SIZE(dd->rcd[ctxt]->pkeys); ++i)
		if ((dd->rcd[ctxt]->pkeys[i] & 0x7fff) == pkey)
			return i;

	/*
	 * Should not get here, this means hardware failed to validate pkeys.
	 * Punt and return index 0.
	 */
	return 0;
}

/**
 * qib_ud_rcv - receive an incoming UD packet
 * @ibp: the port the packet came in on
 * @hdr: the packet header
 * @has_grh: true if the packet has a GRH
 * @data: the packet data
 * @tlen: the packet length
 * @qp: the QP the packet came on
 *
 * This is called from qib_qp_rcv() to process an incoming UD packet
 * for the given QP.
 * Called at interrupt level.
 */
void qib_ud_rcv(struct qib_ibport *ibp, struct qib_ib_header *hdr,
		int has_grh, void *data, u32 tlen, struct rvt_qp *qp)
{
	struct qib_other_headers *ohdr;
	int opcode;
	u32 hdrsize;
	u32 pad;
	struct ib_wc wc;
	u32 qkey;
	u32 src_qp;
	u16 dlid;

	/* Check for GRH */
	if (!has_grh) {
		ohdr = &hdr->u.oth;
		hdrsize = 8 + 12 + 8;   /* LRH + BTH + DETH */
	} else {
		ohdr = &hdr->u.l.oth;
		hdrsize = 8 + 40 + 12 + 8; /* LRH + GRH + BTH + DETH */
	}
	qkey = be32_to_cpu(ohdr->u.ud.deth[0]);
	src_qp = be32_to_cpu(ohdr->u.ud.deth[1]) & RVT_QPN_MASK;

	/*
	 * Get the number of bytes the message was padded by
	 * and drop incomplete packets.
	 */
	pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
	if (unlikely(tlen < (hdrsize + pad + 4)))
		goto drop;

	tlen -= hdrsize + pad + 4;

	/*
	 * Check that the permissive LID is only used on QP0
	 * and the QKEY matches (see 9.6.1.4.1 and 9.6.1.5.1).
	 */
	if (qp->ibqp.qp_num) {
		if (unlikely(hdr->lrh[1] == IB_LID_PERMISSIVE ||
			     hdr->lrh[3] == IB_LID_PERMISSIVE))
			goto drop;
		if (qp->ibqp.qp_num > 1) {
			u16 pkey1, pkey2;

			pkey1 = be32_to_cpu(ohdr->bth[0]);
			pkey2 = qib_get_pkey(ibp, qp->s_pkey_index);
			if (unlikely(!qib_pkey_ok(pkey1, pkey2))) {
				qib_bad_pqkey(ibp, IB_NOTICE_TRAP_BAD_PKEY,
					      pkey1,
					      (be16_to_cpu(hdr->lrh[0]) >> 4) &
						0xF,
					      src_qp, qp->ibqp.qp_num,
					      hdr->lrh[3], hdr->lrh[1]);
				return;
			}
		}
		if (unlikely(qkey != qp->qkey)) {
			qib_bad_pqkey(ibp, IB_NOTICE_TRAP_BAD_QKEY, qkey,
				      (be16_to_cpu(hdr->lrh[0]) >> 4) & 0xF,
				      src_qp, qp->ibqp.qp_num,
				      hdr->lrh[3], hdr->lrh[1]);
			return;
		}
		/* Drop invalid MAD packets (see 13.5.3.1). */
		if (unlikely(qp->ibqp.qp_num == 1 &&
			     (tlen != 256 ||
			      (be16_to_cpu(hdr->lrh[0]) >> 12) == 15)))
			goto drop;
	} else {
		struct ib_smp *smp;

		/* Drop invalid MAD packets (see 13.5.3.1). */
		if (tlen != 256 || (be16_to_cpu(hdr->lrh[0]) >> 12) != 15)
			goto drop;
		smp = (struct ib_smp *) data;
		if ((hdr->lrh[1] == IB_LID_PERMISSIVE ||
		     hdr->lrh[3] == IB_LID_PERMISSIVE) &&
		    smp->mgmt_class != IB_MGMT_CLASS_SUBN_DIRECTED_ROUTE)
			goto drop;
	}

	/*
	 * The opcode is in the low byte when its in network order
	 * (top byte when in host order).
	 */
	opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
	if (qp->ibqp.qp_num > 1 &&
	    opcode == IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE) {
		wc.ex.imm_data = ohdr->u.ud.imm_data;
		wc.wc_flags = IB_WC_WITH_IMM;
		tlen -= sizeof(u32);
	} else if (opcode == IB_OPCODE_UD_SEND_ONLY) {
		wc.ex.imm_data = 0;
		wc.wc_flags = 0;
	} else
		goto drop;

	/*
	 * A GRH is expected to precede the data even if not
	 * present on the wire.
	 */
	wc.byte_len = tlen + sizeof(struct ib_grh);

	/*
	 * Get the next work request entry to find where to put the data.
	 */
	if (qp->r_flags & RVT_R_REUSE_SGE)
		qp->r_flags &= ~RVT_R_REUSE_SGE;
	else {
		int ret;

		ret = qib_get_rwqe(qp, 0);
		if (ret < 0) {
			qib_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
			return;
		}
		if (!ret) {
			if (qp->ibqp.qp_num == 0)
				ibp->rvp.n_vl15_dropped++;
			return;
		}
	}
	/* Silently drop packets which are too big. */
	if (unlikely(wc.byte_len > qp->r_len)) {
		qp->r_flags |= RVT_R_REUSE_SGE;
		goto drop;
	}
	if (has_grh) {
		qib_copy_sge(&qp->r_sge, &hdr->u.l.grh,
			     sizeof(struct ib_grh), 1);
		wc.wc_flags |= IB_WC_GRH;
	} else
		qib_skip_sge(&qp->r_sge, sizeof(struct ib_grh), 1);
	qib_copy_sge(&qp->r_sge, data, wc.byte_len - sizeof(struct ib_grh), 1);
	rvt_put_ss(&qp->r_sge);
	if (!test_and_clear_bit(RVT_R_WRID_VALID, &qp->r_aflags))
		return;
	wc.wr_id = qp->r_wr_id;
	wc.status = IB_WC_SUCCESS;
	wc.opcode = IB_WC_RECV;
	wc.vendor_err = 0;
	wc.qp = &qp->ibqp;
	wc.src_qp = src_qp;
	wc.pkey_index = qp->ibqp.qp_type == IB_QPT_GSI ?
		qib_lookup_pkey(ibp, be32_to_cpu(ohdr->bth[0])) : 0;
	wc.slid = be16_to_cpu(hdr->lrh[3]);
	wc.sl = (be16_to_cpu(hdr->lrh[0]) >> 4) & 0xF;
	dlid = be16_to_cpu(hdr->lrh[1]);
	/*
	 * Save the LMC lower bits if the destination LID is a unicast LID.
	 */
	wc.dlid_path_bits = dlid >= be16_to_cpu(IB_MULTICAST_LID_BASE) ? 0 :
		dlid & ((1 << ppd_from_ibp(ibp)->lmc) - 1);
	wc.port_num = qp->port_num;
	/* Signal completion event if the solicited bit is set. */
	rvt_cq_enter(ibcq_to_rvtcq(qp->ibqp.recv_cq), &wc,
		     (ohdr->bth[0] &
			cpu_to_be32(IB_BTH_SOLICITED)) != 0);
	return;

drop:
	ibp->rvp.n_pkt_drops++;
}