xref: /openbmc/linux/drivers/infiniband/hw/qib/qib_ud.c (revision 9cfc5c90)
1 /*
2  * Copyright (c) 2006, 2007, 2008, 2009 QLogic Corporation. All rights reserved.
3  * Copyright (c) 2005, 2006 PathScale, Inc. All rights reserved.
4  *
5  * This software is available to you under a choice of one of two
6  * licenses.  You may choose to be licensed under the terms of the GNU
7  * General Public License (GPL) Version 2, available from the file
8  * COPYING in the main directory of this source tree, or the
9  * OpenIB.org BSD license below:
10  *
11  *     Redistribution and use in source and binary forms, with or
12  *     without modification, are permitted provided that the following
13  *     conditions are met:
14  *
15  *      - Redistributions of source code must retain the above
16  *        copyright notice, this list of conditions and the following
17  *        disclaimer.
18  *
19  *      - Redistributions in binary form must reproduce the above
20  *        copyright notice, this list of conditions and the following
21  *        disclaimer in the documentation and/or other materials
22  *        provided with the distribution.
23  *
24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
28  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
29  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
30  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
31  * SOFTWARE.
32  */
33 
34 #include <rdma/ib_smi.h>
35 
36 #include "qib.h"
37 #include "qib_mad.h"
38 
39 /**
40  * qib_ud_loopback - handle send on loopback QPs
41  * @sqp: the sending QP
42  * @swqe: the send work request
43  *
44  * This is called from qib_make_ud_req() to forward a WQE addressed
45  * to the same HCA.
46  * Note that the receive interrupt handler may be calling qib_ud_rcv()
47  * while this is being called.
48  */
49 static void qib_ud_loopback(struct qib_qp *sqp, struct qib_swqe *swqe)
50 {
51 	struct qib_ibport *ibp = to_iport(sqp->ibqp.device, sqp->port_num);
52 	struct qib_pportdata *ppd;
53 	struct qib_qp *qp;
54 	struct ib_ah_attr *ah_attr;
55 	unsigned long flags;
56 	struct qib_sge_state ssge;
57 	struct qib_sge *sge;
58 	struct ib_wc wc;
59 	u32 length;
60 	enum ib_qp_type sqptype, dqptype;
61 
62 	qp = qib_lookup_qpn(ibp, swqe->ud_wr.remote_qpn);
63 	if (!qp) {
64 		ibp->n_pkt_drops++;
65 		return;
66 	}
67 
68 	sqptype = sqp->ibqp.qp_type == IB_QPT_GSI ?
69 			IB_QPT_UD : sqp->ibqp.qp_type;
70 	dqptype = qp->ibqp.qp_type == IB_QPT_GSI ?
71 			IB_QPT_UD : qp->ibqp.qp_type;
72 
73 	if (dqptype != sqptype ||
74 	    !(ib_qib_state_ops[qp->state] & QIB_PROCESS_RECV_OK)) {
75 		ibp->n_pkt_drops++;
76 		goto drop;
77 	}
78 
79 	ah_attr = &to_iah(swqe->ud_wr.ah)->attr;
80 	ppd = ppd_from_ibp(ibp);
81 
82 	if (qp->ibqp.qp_num > 1) {
83 		u16 pkey1;
84 		u16 pkey2;
85 		u16 lid;
86 
87 		pkey1 = qib_get_pkey(ibp, sqp->s_pkey_index);
88 		pkey2 = qib_get_pkey(ibp, qp->s_pkey_index);
89 		if (unlikely(!qib_pkey_ok(pkey1, pkey2))) {
90 			lid = ppd->lid | (ah_attr->src_path_bits &
91 					  ((1 << ppd->lmc) - 1));
92 			qib_bad_pqkey(ibp, IB_NOTICE_TRAP_BAD_PKEY, pkey1,
93 				      ah_attr->sl,
94 				      sqp->ibqp.qp_num, qp->ibqp.qp_num,
95 				      cpu_to_be16(lid),
96 				      cpu_to_be16(ah_attr->dlid));
97 			goto drop;
98 		}
99 	}
100 
101 	/*
102 	 * Check that the qkey matches (except for QP0, see 9.6.1.4.1).
103 	 * Qkeys with the high order bit set mean use the
104 	 * qkey from the QP context instead of the WR (see 10.2.5).
105 	 */
106 	if (qp->ibqp.qp_num) {
107 		u32 qkey;
108 
109 		qkey = (int)swqe->ud_wr.remote_qkey < 0 ?
110 			sqp->qkey : swqe->ud_wr.remote_qkey;
111 		if (unlikely(qkey != qp->qkey)) {
112 			u16 lid;
113 
114 			lid = ppd->lid | (ah_attr->src_path_bits &
115 					  ((1 << ppd->lmc) - 1));
116 			qib_bad_pqkey(ibp, IB_NOTICE_TRAP_BAD_QKEY, qkey,
117 				      ah_attr->sl,
118 				      sqp->ibqp.qp_num, qp->ibqp.qp_num,
119 				      cpu_to_be16(lid),
120 				      cpu_to_be16(ah_attr->dlid));
121 			goto drop;
122 		}
123 	}
124 
125 	/*
126 	 * A GRH is expected to precede the data even if not
127 	 * present on the wire.
128 	 */
129 	length = swqe->length;
130 	memset(&wc, 0, sizeof(wc));
131 	wc.byte_len = length + sizeof(struct ib_grh);
132 
133 	if (swqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
134 		wc.wc_flags = IB_WC_WITH_IMM;
135 		wc.ex.imm_data = swqe->wr.ex.imm_data;
136 	}
137 
138 	spin_lock_irqsave(&qp->r_lock, flags);
139 
140 	/*
141 	 * Get the next work request entry to find where to put the data.
142 	 */
143 	if (qp->r_flags & QIB_R_REUSE_SGE)
144 		qp->r_flags &= ~QIB_R_REUSE_SGE;
145 	else {
146 		int ret;
147 
148 		ret = qib_get_rwqe(qp, 0);
149 		if (ret < 0) {
150 			qib_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
151 			goto bail_unlock;
152 		}
153 		if (!ret) {
154 			if (qp->ibqp.qp_num == 0)
155 				ibp->n_vl15_dropped++;
156 			goto bail_unlock;
157 		}
158 	}
159 	/* Silently drop packets which are too big. */
160 	if (unlikely(wc.byte_len > qp->r_len)) {
161 		qp->r_flags |= QIB_R_REUSE_SGE;
162 		ibp->n_pkt_drops++;
163 		goto bail_unlock;
164 	}
165 
166 	if (ah_attr->ah_flags & IB_AH_GRH) {
167 		qib_copy_sge(&qp->r_sge, &ah_attr->grh,
168 			     sizeof(struct ib_grh), 1);
169 		wc.wc_flags |= IB_WC_GRH;
170 	} else
171 		qib_skip_sge(&qp->r_sge, sizeof(struct ib_grh), 1);
172 	ssge.sg_list = swqe->sg_list + 1;
173 	ssge.sge = *swqe->sg_list;
174 	ssge.num_sge = swqe->wr.num_sge;
175 	sge = &ssge.sge;
176 	while (length) {
177 		u32 len = sge->length;
178 
179 		if (len > length)
180 			len = length;
181 		if (len > sge->sge_length)
182 			len = sge->sge_length;
183 		BUG_ON(len == 0);
184 		qib_copy_sge(&qp->r_sge, sge->vaddr, len, 1);
185 		sge->vaddr += len;
186 		sge->length -= len;
187 		sge->sge_length -= len;
188 		if (sge->sge_length == 0) {
189 			if (--ssge.num_sge)
190 				*sge = *ssge.sg_list++;
191 		} else if (sge->length == 0 && sge->mr->lkey) {
192 			if (++sge->n >= QIB_SEGSZ) {
193 				if (++sge->m >= sge->mr->mapsz)
194 					break;
195 				sge->n = 0;
196 			}
197 			sge->vaddr =
198 				sge->mr->map[sge->m]->segs[sge->n].vaddr;
199 			sge->length =
200 				sge->mr->map[sge->m]->segs[sge->n].length;
201 		}
202 		length -= len;
203 	}
204 	qib_put_ss(&qp->r_sge);
205 	if (!test_and_clear_bit(QIB_R_WRID_VALID, &qp->r_aflags))
206 		goto bail_unlock;
207 	wc.wr_id = qp->r_wr_id;
208 	wc.status = IB_WC_SUCCESS;
209 	wc.opcode = IB_WC_RECV;
210 	wc.qp = &qp->ibqp;
211 	wc.src_qp = sqp->ibqp.qp_num;
212 	wc.pkey_index = qp->ibqp.qp_type == IB_QPT_GSI ?
213 		swqe->ud_wr.pkey_index : 0;
214 	wc.slid = ppd->lid | (ah_attr->src_path_bits & ((1 << ppd->lmc) - 1));
215 	wc.sl = ah_attr->sl;
216 	wc.dlid_path_bits = ah_attr->dlid & ((1 << ppd->lmc) - 1);
217 	wc.port_num = qp->port_num;
218 	/* Signal completion event if the solicited bit is set. */
219 	qib_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
220 		     swqe->wr.send_flags & IB_SEND_SOLICITED);
221 	ibp->n_loop_pkts++;
222 bail_unlock:
223 	spin_unlock_irqrestore(&qp->r_lock, flags);
224 drop:
225 	if (atomic_dec_and_test(&qp->refcount))
226 		wake_up(&qp->wait);
227 }
228 
229 /**
230  * qib_make_ud_req - construct a UD request packet
231  * @qp: the QP
232  *
233  * Return 1 if constructed; otherwise, return 0.
234  */
235 int qib_make_ud_req(struct qib_qp *qp)
236 {
237 	struct qib_other_headers *ohdr;
238 	struct ib_ah_attr *ah_attr;
239 	struct qib_pportdata *ppd;
240 	struct qib_ibport *ibp;
241 	struct qib_swqe *wqe;
242 	unsigned long flags;
243 	u32 nwords;
244 	u32 extra_bytes;
245 	u32 bth0;
246 	u16 lrh0;
247 	u16 lid;
248 	int ret = 0;
249 	int next_cur;
250 
251 	spin_lock_irqsave(&qp->s_lock, flags);
252 
253 	if (!(ib_qib_state_ops[qp->state] & QIB_PROCESS_NEXT_SEND_OK)) {
254 		if (!(ib_qib_state_ops[qp->state] & QIB_FLUSH_SEND))
255 			goto bail;
256 		/* We are in the error state, flush the work request. */
257 		if (qp->s_last == qp->s_head)
258 			goto bail;
259 		/* If DMAs are in progress, we can't flush immediately. */
260 		if (atomic_read(&qp->s_dma_busy)) {
261 			qp->s_flags |= QIB_S_WAIT_DMA;
262 			goto bail;
263 		}
264 		wqe = get_swqe_ptr(qp, qp->s_last);
265 		qib_send_complete(qp, wqe, IB_WC_WR_FLUSH_ERR);
266 		goto done;
267 	}
268 
269 	if (qp->s_cur == qp->s_head)
270 		goto bail;
271 
272 	wqe = get_swqe_ptr(qp, qp->s_cur);
273 	next_cur = qp->s_cur + 1;
274 	if (next_cur >= qp->s_size)
275 		next_cur = 0;
276 
277 	/* Construct the header. */
278 	ibp = to_iport(qp->ibqp.device, qp->port_num);
279 	ppd = ppd_from_ibp(ibp);
280 	ah_attr = &to_iah(wqe->ud_wr.ah)->attr;
281 	if (ah_attr->dlid >= QIB_MULTICAST_LID_BASE) {
282 		if (ah_attr->dlid != QIB_PERMISSIVE_LID)
283 			this_cpu_inc(ibp->pmastats->n_multicast_xmit);
284 		else
285 			this_cpu_inc(ibp->pmastats->n_unicast_xmit);
286 	} else {
287 		this_cpu_inc(ibp->pmastats->n_unicast_xmit);
288 		lid = ah_attr->dlid & ~((1 << ppd->lmc) - 1);
289 		if (unlikely(lid == ppd->lid)) {
290 			/*
291 			 * If DMAs are in progress, we can't generate
292 			 * a completion for the loopback packet since
293 			 * it would be out of order.
294 			 * XXX Instead of waiting, we could queue a
295 			 * zero length descriptor so we get a callback.
296 			 */
297 			if (atomic_read(&qp->s_dma_busy)) {
298 				qp->s_flags |= QIB_S_WAIT_DMA;
299 				goto bail;
300 			}
301 			qp->s_cur = next_cur;
302 			spin_unlock_irqrestore(&qp->s_lock, flags);
303 			qib_ud_loopback(qp, wqe);
304 			spin_lock_irqsave(&qp->s_lock, flags);
305 			qib_send_complete(qp, wqe, IB_WC_SUCCESS);
306 			goto done;
307 		}
308 	}
309 
310 	qp->s_cur = next_cur;
311 	extra_bytes = -wqe->length & 3;
312 	nwords = (wqe->length + extra_bytes) >> 2;
313 
314 	/* header size in 32-bit words LRH+BTH+DETH = (8+12+8)/4. */
315 	qp->s_hdrwords = 7;
316 	qp->s_cur_size = wqe->length;
317 	qp->s_cur_sge = &qp->s_sge;
318 	qp->s_srate = ah_attr->static_rate;
319 	qp->s_wqe = wqe;
320 	qp->s_sge.sge = wqe->sg_list[0];
321 	qp->s_sge.sg_list = wqe->sg_list + 1;
322 	qp->s_sge.num_sge = wqe->wr.num_sge;
323 	qp->s_sge.total_len = wqe->length;
324 
325 	if (ah_attr->ah_flags & IB_AH_GRH) {
326 		/* Header size in 32-bit words. */
327 		qp->s_hdrwords += qib_make_grh(ibp, &qp->s_hdr->u.l.grh,
328 					       &ah_attr->grh,
329 					       qp->s_hdrwords, nwords);
330 		lrh0 = QIB_LRH_GRH;
331 		ohdr = &qp->s_hdr->u.l.oth;
332 		/*
333 		 * Don't worry about sending to locally attached multicast
334 		 * QPs.  It is unspecified by the spec. what happens.
335 		 */
336 	} else {
337 		/* Header size in 32-bit words. */
338 		lrh0 = QIB_LRH_BTH;
339 		ohdr = &qp->s_hdr->u.oth;
340 	}
341 	if (wqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
342 		qp->s_hdrwords++;
343 		ohdr->u.ud.imm_data = wqe->wr.ex.imm_data;
344 		bth0 = IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE << 24;
345 	} else
346 		bth0 = IB_OPCODE_UD_SEND_ONLY << 24;
347 	lrh0 |= ah_attr->sl << 4;
348 	if (qp->ibqp.qp_type == IB_QPT_SMI)
349 		lrh0 |= 0xF000; /* Set VL (see ch. 13.5.3.1) */
350 	else
351 		lrh0 |= ibp->sl_to_vl[ah_attr->sl] << 12;
352 	qp->s_hdr->lrh[0] = cpu_to_be16(lrh0);
353 	qp->s_hdr->lrh[1] = cpu_to_be16(ah_attr->dlid);  /* DEST LID */
354 	qp->s_hdr->lrh[2] = cpu_to_be16(qp->s_hdrwords + nwords + SIZE_OF_CRC);
355 	lid = ppd->lid;
356 	if (lid) {
357 		lid |= ah_attr->src_path_bits & ((1 << ppd->lmc) - 1);
358 		qp->s_hdr->lrh[3] = cpu_to_be16(lid);
359 	} else
360 		qp->s_hdr->lrh[3] = IB_LID_PERMISSIVE;
361 	if (wqe->wr.send_flags & IB_SEND_SOLICITED)
362 		bth0 |= IB_BTH_SOLICITED;
363 	bth0 |= extra_bytes << 20;
364 	bth0 |= qp->ibqp.qp_type == IB_QPT_SMI ? QIB_DEFAULT_P_KEY :
365 		qib_get_pkey(ibp, qp->ibqp.qp_type == IB_QPT_GSI ?
366 			     wqe->ud_wr.pkey_index : qp->s_pkey_index);
367 	ohdr->bth[0] = cpu_to_be32(bth0);
368 	/*
369 	 * Use the multicast QP if the destination LID is a multicast LID.
370 	 */
371 	ohdr->bth[1] = ah_attr->dlid >= QIB_MULTICAST_LID_BASE &&
372 		ah_attr->dlid != QIB_PERMISSIVE_LID ?
373 		cpu_to_be32(QIB_MULTICAST_QPN) :
374 		cpu_to_be32(wqe->ud_wr.remote_qpn);
375 	ohdr->bth[2] = cpu_to_be32(qp->s_next_psn++ & QIB_PSN_MASK);
376 	/*
377 	 * Qkeys with the high order bit set mean use the
378 	 * qkey from the QP context instead of the WR (see 10.2.5).
379 	 */
380 	ohdr->u.ud.deth[0] = cpu_to_be32((int)wqe->ud_wr.remote_qkey < 0 ?
381 					 qp->qkey : wqe->ud_wr.remote_qkey);
382 	ohdr->u.ud.deth[1] = cpu_to_be32(qp->ibqp.qp_num);
383 
384 done:
385 	ret = 1;
386 	goto unlock;
387 
388 bail:
389 	qp->s_flags &= ~QIB_S_BUSY;
390 unlock:
391 	spin_unlock_irqrestore(&qp->s_lock, flags);
392 	return ret;
393 }
394 
395 static unsigned qib_lookup_pkey(struct qib_ibport *ibp, u16 pkey)
396 {
397 	struct qib_pportdata *ppd = ppd_from_ibp(ibp);
398 	struct qib_devdata *dd = ppd->dd;
399 	unsigned ctxt = ppd->hw_pidx;
400 	unsigned i;
401 
402 	pkey &= 0x7fff;	/* remove limited/full membership bit */
403 
404 	for (i = 0; i < ARRAY_SIZE(dd->rcd[ctxt]->pkeys); ++i)
405 		if ((dd->rcd[ctxt]->pkeys[i] & 0x7fff) == pkey)
406 			return i;
407 
408 	/*
409 	 * Should not get here, this means hardware failed to validate pkeys.
410 	 * Punt and return index 0.
411 	 */
412 	return 0;
413 }
414 
415 /**
416  * qib_ud_rcv - receive an incoming UD packet
417  * @ibp: the port the packet came in on
418  * @hdr: the packet header
419  * @has_grh: true if the packet has a GRH
420  * @data: the packet data
421  * @tlen: the packet length
422  * @qp: the QP the packet came on
423  *
424  * This is called from qib_qp_rcv() to process an incoming UD packet
425  * for the given QP.
426  * Called at interrupt level.
427  */
428 void qib_ud_rcv(struct qib_ibport *ibp, struct qib_ib_header *hdr,
429 		int has_grh, void *data, u32 tlen, struct qib_qp *qp)
430 {
431 	struct qib_other_headers *ohdr;
432 	int opcode;
433 	u32 hdrsize;
434 	u32 pad;
435 	struct ib_wc wc;
436 	u32 qkey;
437 	u32 src_qp;
438 	u16 dlid;
439 
440 	/* Check for GRH */
441 	if (!has_grh) {
442 		ohdr = &hdr->u.oth;
443 		hdrsize = 8 + 12 + 8;   /* LRH + BTH + DETH */
444 	} else {
445 		ohdr = &hdr->u.l.oth;
446 		hdrsize = 8 + 40 + 12 + 8; /* LRH + GRH + BTH + DETH */
447 	}
448 	qkey = be32_to_cpu(ohdr->u.ud.deth[0]);
449 	src_qp = be32_to_cpu(ohdr->u.ud.deth[1]) & QIB_QPN_MASK;
450 
451 	/*
452 	 * Get the number of bytes the message was padded by
453 	 * and drop incomplete packets.
454 	 */
455 	pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
456 	if (unlikely(tlen < (hdrsize + pad + 4)))
457 		goto drop;
458 
459 	tlen -= hdrsize + pad + 4;
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 			goto drop;
469 		if (qp->ibqp.qp_num > 1) {
470 			u16 pkey1, pkey2;
471 
472 			pkey1 = be32_to_cpu(ohdr->bth[0]);
473 			pkey2 = qib_get_pkey(ibp, qp->s_pkey_index);
474 			if (unlikely(!qib_pkey_ok(pkey1, pkey2))) {
475 				qib_bad_pqkey(ibp, IB_NOTICE_TRAP_BAD_PKEY,
476 					      pkey1,
477 					      (be16_to_cpu(hdr->lrh[0]) >> 4) &
478 						0xF,
479 					      src_qp, qp->ibqp.qp_num,
480 					      hdr->lrh[3], hdr->lrh[1]);
481 				return;
482 			}
483 		}
484 		if (unlikely(qkey != qp->qkey)) {
485 			qib_bad_pqkey(ibp, IB_NOTICE_TRAP_BAD_QKEY, qkey,
486 				      (be16_to_cpu(hdr->lrh[0]) >> 4) & 0xF,
487 				      src_qp, qp->ibqp.qp_num,
488 				      hdr->lrh[3], hdr->lrh[1]);
489 			return;
490 		}
491 		/* Drop invalid MAD packets (see 13.5.3.1). */
492 		if (unlikely(qp->ibqp.qp_num == 1 &&
493 			     (tlen != 256 ||
494 			      (be16_to_cpu(hdr->lrh[0]) >> 12) == 15)))
495 			goto drop;
496 	} else {
497 		struct ib_smp *smp;
498 
499 		/* Drop invalid MAD packets (see 13.5.3.1). */
500 		if (tlen != 256 || (be16_to_cpu(hdr->lrh[0]) >> 12) != 15)
501 			goto drop;
502 		smp = (struct ib_smp *) data;
503 		if ((hdr->lrh[1] == IB_LID_PERMISSIVE ||
504 		     hdr->lrh[3] == IB_LID_PERMISSIVE) &&
505 		    smp->mgmt_class != IB_MGMT_CLASS_SUBN_DIRECTED_ROUTE)
506 			goto drop;
507 	}
508 
509 	/*
510 	 * The opcode is in the low byte when its in network order
511 	 * (top byte when in host order).
512 	 */
513 	opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
514 	if (qp->ibqp.qp_num > 1 &&
515 	    opcode == IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE) {
516 		wc.ex.imm_data = ohdr->u.ud.imm_data;
517 		wc.wc_flags = IB_WC_WITH_IMM;
518 		tlen -= sizeof(u32);
519 	} else if (opcode == IB_OPCODE_UD_SEND_ONLY) {
520 		wc.ex.imm_data = 0;
521 		wc.wc_flags = 0;
522 	} else
523 		goto drop;
524 
525 	/*
526 	 * A GRH is expected to precede the data even if not
527 	 * present on the wire.
528 	 */
529 	wc.byte_len = tlen + sizeof(struct ib_grh);
530 
531 	/*
532 	 * Get the next work request entry to find where to put the data.
533 	 */
534 	if (qp->r_flags & QIB_R_REUSE_SGE)
535 		qp->r_flags &= ~QIB_R_REUSE_SGE;
536 	else {
537 		int ret;
538 
539 		ret = qib_get_rwqe(qp, 0);
540 		if (ret < 0) {
541 			qib_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
542 			return;
543 		}
544 		if (!ret) {
545 			if (qp->ibqp.qp_num == 0)
546 				ibp->n_vl15_dropped++;
547 			return;
548 		}
549 	}
550 	/* Silently drop packets which are too big. */
551 	if (unlikely(wc.byte_len > qp->r_len)) {
552 		qp->r_flags |= QIB_R_REUSE_SGE;
553 		goto drop;
554 	}
555 	if (has_grh) {
556 		qib_copy_sge(&qp->r_sge, &hdr->u.l.grh,
557 			     sizeof(struct ib_grh), 1);
558 		wc.wc_flags |= IB_WC_GRH;
559 	} else
560 		qib_skip_sge(&qp->r_sge, sizeof(struct ib_grh), 1);
561 	qib_copy_sge(&qp->r_sge, data, wc.byte_len - sizeof(struct ib_grh), 1);
562 	qib_put_ss(&qp->r_sge);
563 	if (!test_and_clear_bit(QIB_R_WRID_VALID, &qp->r_aflags))
564 		return;
565 	wc.wr_id = qp->r_wr_id;
566 	wc.status = IB_WC_SUCCESS;
567 	wc.opcode = IB_WC_RECV;
568 	wc.vendor_err = 0;
569 	wc.qp = &qp->ibqp;
570 	wc.src_qp = src_qp;
571 	wc.pkey_index = qp->ibqp.qp_type == IB_QPT_GSI ?
572 		qib_lookup_pkey(ibp, be32_to_cpu(ohdr->bth[0])) : 0;
573 	wc.slid = be16_to_cpu(hdr->lrh[3]);
574 	wc.sl = (be16_to_cpu(hdr->lrh[0]) >> 4) & 0xF;
575 	dlid = be16_to_cpu(hdr->lrh[1]);
576 	/*
577 	 * Save the LMC lower bits if the destination LID is a unicast LID.
578 	 */
579 	wc.dlid_path_bits = dlid >= QIB_MULTICAST_LID_BASE ? 0 :
580 		dlid & ((1 << ppd_from_ibp(ibp)->lmc) - 1);
581 	wc.port_num = qp->port_num;
582 	/* Signal completion event if the solicited bit is set. */
583 	qib_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
584 		     (ohdr->bth[0] &
585 			cpu_to_be32(IB_BTH_SOLICITED)) != 0);
586 	return;
587 
588 drop:
589 	ibp->n_pkt_drops++;
590 }
591