xref: /openbmc/linux/drivers/infiniband/hw/qib/qib_ud.c (revision ee89bd6b)
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 
61 	qp = qib_lookup_qpn(ibp, swqe->wr.wr.ud.remote_qpn);
62 	if (!qp) {
63 		ibp->n_pkt_drops++;
64 		return;
65 	}
66 	if (qp->ibqp.qp_type != sqp->ibqp.qp_type ||
67 	    !(ib_qib_state_ops[qp->state] & QIB_PROCESS_RECV_OK)) {
68 		ibp->n_pkt_drops++;
69 		goto drop;
70 	}
71 
72 	ah_attr = &to_iah(swqe->wr.wr.ud.ah)->attr;
73 	ppd = ppd_from_ibp(ibp);
74 
75 	if (qp->ibqp.qp_num > 1) {
76 		u16 pkey1;
77 		u16 pkey2;
78 		u16 lid;
79 
80 		pkey1 = qib_get_pkey(ibp, sqp->s_pkey_index);
81 		pkey2 = qib_get_pkey(ibp, qp->s_pkey_index);
82 		if (unlikely(!qib_pkey_ok(pkey1, pkey2))) {
83 			lid = ppd->lid | (ah_attr->src_path_bits &
84 					  ((1 << ppd->lmc) - 1));
85 			qib_bad_pqkey(ibp, IB_NOTICE_TRAP_BAD_PKEY, pkey1,
86 				      ah_attr->sl,
87 				      sqp->ibqp.qp_num, qp->ibqp.qp_num,
88 				      cpu_to_be16(lid),
89 				      cpu_to_be16(ah_attr->dlid));
90 			goto drop;
91 		}
92 	}
93 
94 	/*
95 	 * Check that the qkey matches (except for QP0, see 9.6.1.4.1).
96 	 * Qkeys with the high order bit set mean use the
97 	 * qkey from the QP context instead of the WR (see 10.2.5).
98 	 */
99 	if (qp->ibqp.qp_num) {
100 		u32 qkey;
101 
102 		qkey = (int)swqe->wr.wr.ud.remote_qkey < 0 ?
103 			sqp->qkey : swqe->wr.wr.ud.remote_qkey;
104 		if (unlikely(qkey != qp->qkey)) {
105 			u16 lid;
106 
107 			lid = ppd->lid | (ah_attr->src_path_bits &
108 					  ((1 << ppd->lmc) - 1));
109 			qib_bad_pqkey(ibp, IB_NOTICE_TRAP_BAD_QKEY, qkey,
110 				      ah_attr->sl,
111 				      sqp->ibqp.qp_num, qp->ibqp.qp_num,
112 				      cpu_to_be16(lid),
113 				      cpu_to_be16(ah_attr->dlid));
114 			goto drop;
115 		}
116 	}
117 
118 	/*
119 	 * A GRH is expected to precede the data even if not
120 	 * present on the wire.
121 	 */
122 	length = swqe->length;
123 	memset(&wc, 0, sizeof wc);
124 	wc.byte_len = length + sizeof(struct ib_grh);
125 
126 	if (swqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
127 		wc.wc_flags = IB_WC_WITH_IMM;
128 		wc.ex.imm_data = swqe->wr.ex.imm_data;
129 	}
130 
131 	spin_lock_irqsave(&qp->r_lock, flags);
132 
133 	/*
134 	 * Get the next work request entry to find where to put the data.
135 	 */
136 	if (qp->r_flags & QIB_R_REUSE_SGE)
137 		qp->r_flags &= ~QIB_R_REUSE_SGE;
138 	else {
139 		int ret;
140 
141 		ret = qib_get_rwqe(qp, 0);
142 		if (ret < 0) {
143 			qib_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
144 			goto bail_unlock;
145 		}
146 		if (!ret) {
147 			if (qp->ibqp.qp_num == 0)
148 				ibp->n_vl15_dropped++;
149 			goto bail_unlock;
150 		}
151 	}
152 	/* Silently drop packets which are too big. */
153 	if (unlikely(wc.byte_len > qp->r_len)) {
154 		qp->r_flags |= QIB_R_REUSE_SGE;
155 		ibp->n_pkt_drops++;
156 		goto bail_unlock;
157 	}
158 
159 	if (ah_attr->ah_flags & IB_AH_GRH) {
160 		qib_copy_sge(&qp->r_sge, &ah_attr->grh,
161 			     sizeof(struct ib_grh), 1);
162 		wc.wc_flags |= IB_WC_GRH;
163 	} else
164 		qib_skip_sge(&qp->r_sge, sizeof(struct ib_grh), 1);
165 	ssge.sg_list = swqe->sg_list + 1;
166 	ssge.sge = *swqe->sg_list;
167 	ssge.num_sge = swqe->wr.num_sge;
168 	sge = &ssge.sge;
169 	while (length) {
170 		u32 len = sge->length;
171 
172 		if (len > length)
173 			len = length;
174 		if (len > sge->sge_length)
175 			len = sge->sge_length;
176 		BUG_ON(len == 0);
177 		qib_copy_sge(&qp->r_sge, sge->vaddr, len, 1);
178 		sge->vaddr += len;
179 		sge->length -= len;
180 		sge->sge_length -= len;
181 		if (sge->sge_length == 0) {
182 			if (--ssge.num_sge)
183 				*sge = *ssge.sg_list++;
184 		} else if (sge->length == 0 && sge->mr->lkey) {
185 			if (++sge->n >= QIB_SEGSZ) {
186 				if (++sge->m >= sge->mr->mapsz)
187 					break;
188 				sge->n = 0;
189 			}
190 			sge->vaddr =
191 				sge->mr->map[sge->m]->segs[sge->n].vaddr;
192 			sge->length =
193 				sge->mr->map[sge->m]->segs[sge->n].length;
194 		}
195 		length -= len;
196 	}
197 	qib_put_ss(&qp->r_sge);
198 	if (!test_and_clear_bit(QIB_R_WRID_VALID, &qp->r_aflags))
199 		goto bail_unlock;
200 	wc.wr_id = qp->r_wr_id;
201 	wc.status = IB_WC_SUCCESS;
202 	wc.opcode = IB_WC_RECV;
203 	wc.qp = &qp->ibqp;
204 	wc.src_qp = sqp->ibqp.qp_num;
205 	wc.pkey_index = qp->ibqp.qp_type == IB_QPT_GSI ?
206 		swqe->wr.wr.ud.pkey_index : 0;
207 	wc.slid = ppd->lid | (ah_attr->src_path_bits & ((1 << ppd->lmc) - 1));
208 	wc.sl = ah_attr->sl;
209 	wc.dlid_path_bits = ah_attr->dlid & ((1 << ppd->lmc) - 1);
210 	wc.port_num = qp->port_num;
211 	/* Signal completion event if the solicited bit is set. */
212 	qib_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
213 		     swqe->wr.send_flags & IB_SEND_SOLICITED);
214 	ibp->n_loop_pkts++;
215 bail_unlock:
216 	spin_unlock_irqrestore(&qp->r_lock, flags);
217 drop:
218 	if (atomic_dec_and_test(&qp->refcount))
219 		wake_up(&qp->wait);
220 }
221 
222 /**
223  * qib_make_ud_req - construct a UD request packet
224  * @qp: the QP
225  *
226  * Return 1 if constructed; otherwise, return 0.
227  */
228 int qib_make_ud_req(struct qib_qp *qp)
229 {
230 	struct qib_other_headers *ohdr;
231 	struct ib_ah_attr *ah_attr;
232 	struct qib_pportdata *ppd;
233 	struct qib_ibport *ibp;
234 	struct qib_swqe *wqe;
235 	unsigned long flags;
236 	u32 nwords;
237 	u32 extra_bytes;
238 	u32 bth0;
239 	u16 lrh0;
240 	u16 lid;
241 	int ret = 0;
242 	int next_cur;
243 
244 	spin_lock_irqsave(&qp->s_lock, flags);
245 
246 	if (!(ib_qib_state_ops[qp->state] & QIB_PROCESS_NEXT_SEND_OK)) {
247 		if (!(ib_qib_state_ops[qp->state] & QIB_FLUSH_SEND))
248 			goto bail;
249 		/* We are in the error state, flush the work request. */
250 		if (qp->s_last == qp->s_head)
251 			goto bail;
252 		/* If DMAs are in progress, we can't flush immediately. */
253 		if (atomic_read(&qp->s_dma_busy)) {
254 			qp->s_flags |= QIB_S_WAIT_DMA;
255 			goto bail;
256 		}
257 		wqe = get_swqe_ptr(qp, qp->s_last);
258 		qib_send_complete(qp, wqe, IB_WC_WR_FLUSH_ERR);
259 		goto done;
260 	}
261 
262 	if (qp->s_cur == qp->s_head)
263 		goto bail;
264 
265 	wqe = get_swqe_ptr(qp, qp->s_cur);
266 	next_cur = qp->s_cur + 1;
267 	if (next_cur >= qp->s_size)
268 		next_cur = 0;
269 
270 	/* Construct the header. */
271 	ibp = to_iport(qp->ibqp.device, qp->port_num);
272 	ppd = ppd_from_ibp(ibp);
273 	ah_attr = &to_iah(wqe->wr.wr.ud.ah)->attr;
274 	if (ah_attr->dlid >= QIB_MULTICAST_LID_BASE) {
275 		if (ah_attr->dlid != QIB_PERMISSIVE_LID)
276 			ibp->n_multicast_xmit++;
277 		else
278 			ibp->n_unicast_xmit++;
279 	} else {
280 		ibp->n_unicast_xmit++;
281 		lid = ah_attr->dlid & ~((1 << ppd->lmc) - 1);
282 		if (unlikely(lid == ppd->lid)) {
283 			/*
284 			 * If DMAs are in progress, we can't generate
285 			 * a completion for the loopback packet since
286 			 * it would be out of order.
287 			 * XXX Instead of waiting, we could queue a
288 			 * zero length descriptor so we get a callback.
289 			 */
290 			if (atomic_read(&qp->s_dma_busy)) {
291 				qp->s_flags |= QIB_S_WAIT_DMA;
292 				goto bail;
293 			}
294 			qp->s_cur = next_cur;
295 			spin_unlock_irqrestore(&qp->s_lock, flags);
296 			qib_ud_loopback(qp, wqe);
297 			spin_lock_irqsave(&qp->s_lock, flags);
298 			qib_send_complete(qp, wqe, IB_WC_SUCCESS);
299 			goto done;
300 		}
301 	}
302 
303 	qp->s_cur = next_cur;
304 	extra_bytes = -wqe->length & 3;
305 	nwords = (wqe->length + extra_bytes) >> 2;
306 
307 	/* header size in 32-bit words LRH+BTH+DETH = (8+12+8)/4. */
308 	qp->s_hdrwords = 7;
309 	qp->s_cur_size = wqe->length;
310 	qp->s_cur_sge = &qp->s_sge;
311 	qp->s_srate = ah_attr->static_rate;
312 	qp->s_wqe = wqe;
313 	qp->s_sge.sge = wqe->sg_list[0];
314 	qp->s_sge.sg_list = wqe->sg_list + 1;
315 	qp->s_sge.num_sge = wqe->wr.num_sge;
316 	qp->s_sge.total_len = wqe->length;
317 
318 	if (ah_attr->ah_flags & IB_AH_GRH) {
319 		/* Header size in 32-bit words. */
320 		qp->s_hdrwords += qib_make_grh(ibp, &qp->s_hdr->u.l.grh,
321 					       &ah_attr->grh,
322 					       qp->s_hdrwords, nwords);
323 		lrh0 = QIB_LRH_GRH;
324 		ohdr = &qp->s_hdr->u.l.oth;
325 		/*
326 		 * Don't worry about sending to locally attached multicast
327 		 * QPs.  It is unspecified by the spec. what happens.
328 		 */
329 	} else {
330 		/* Header size in 32-bit words. */
331 		lrh0 = QIB_LRH_BTH;
332 		ohdr = &qp->s_hdr->u.oth;
333 	}
334 	if (wqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
335 		qp->s_hdrwords++;
336 		ohdr->u.ud.imm_data = wqe->wr.ex.imm_data;
337 		bth0 = IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE << 24;
338 	} else
339 		bth0 = IB_OPCODE_UD_SEND_ONLY << 24;
340 	lrh0 |= ah_attr->sl << 4;
341 	if (qp->ibqp.qp_type == IB_QPT_SMI)
342 		lrh0 |= 0xF000; /* Set VL (see ch. 13.5.3.1) */
343 	else
344 		lrh0 |= ibp->sl_to_vl[ah_attr->sl] << 12;
345 	qp->s_hdr->lrh[0] = cpu_to_be16(lrh0);
346 	qp->s_hdr->lrh[1] = cpu_to_be16(ah_attr->dlid);  /* DEST LID */
347 	qp->s_hdr->lrh[2] = cpu_to_be16(qp->s_hdrwords + nwords + SIZE_OF_CRC);
348 	lid = ppd->lid;
349 	if (lid) {
350 		lid |= ah_attr->src_path_bits & ((1 << ppd->lmc) - 1);
351 		qp->s_hdr->lrh[3] = cpu_to_be16(lid);
352 	} else
353 		qp->s_hdr->lrh[3] = IB_LID_PERMISSIVE;
354 	if (wqe->wr.send_flags & IB_SEND_SOLICITED)
355 		bth0 |= IB_BTH_SOLICITED;
356 	bth0 |= extra_bytes << 20;
357 	bth0 |= qp->ibqp.qp_type == IB_QPT_SMI ? QIB_DEFAULT_P_KEY :
358 		qib_get_pkey(ibp, qp->ibqp.qp_type == IB_QPT_GSI ?
359 			     wqe->wr.wr.ud.pkey_index : qp->s_pkey_index);
360 	ohdr->bth[0] = cpu_to_be32(bth0);
361 	/*
362 	 * Use the multicast QP if the destination LID is a multicast LID.
363 	 */
364 	ohdr->bth[1] = ah_attr->dlid >= QIB_MULTICAST_LID_BASE &&
365 		ah_attr->dlid != QIB_PERMISSIVE_LID ?
366 		cpu_to_be32(QIB_MULTICAST_QPN) :
367 		cpu_to_be32(wqe->wr.wr.ud.remote_qpn);
368 	ohdr->bth[2] = cpu_to_be32(qp->s_next_psn++ & QIB_PSN_MASK);
369 	/*
370 	 * Qkeys with the high order bit set mean use the
371 	 * qkey from the QP context instead of the WR (see 10.2.5).
372 	 */
373 	ohdr->u.ud.deth[0] = cpu_to_be32((int)wqe->wr.wr.ud.remote_qkey < 0 ?
374 					 qp->qkey : wqe->wr.wr.ud.remote_qkey);
375 	ohdr->u.ud.deth[1] = cpu_to_be32(qp->ibqp.qp_num);
376 
377 done:
378 	ret = 1;
379 	goto unlock;
380 
381 bail:
382 	qp->s_flags &= ~QIB_S_BUSY;
383 unlock:
384 	spin_unlock_irqrestore(&qp->s_lock, flags);
385 	return ret;
386 }
387 
388 static unsigned qib_lookup_pkey(struct qib_ibport *ibp, u16 pkey)
389 {
390 	struct qib_pportdata *ppd = ppd_from_ibp(ibp);
391 	struct qib_devdata *dd = ppd->dd;
392 	unsigned ctxt = ppd->hw_pidx;
393 	unsigned i;
394 
395 	pkey &= 0x7fff;	/* remove limited/full membership bit */
396 
397 	for (i = 0; i < ARRAY_SIZE(dd->rcd[ctxt]->pkeys); ++i)
398 		if ((dd->rcd[ctxt]->pkeys[i] & 0x7fff) == pkey)
399 			return i;
400 
401 	/*
402 	 * Should not get here, this means hardware failed to validate pkeys.
403 	 * Punt and return index 0.
404 	 */
405 	return 0;
406 }
407 
408 /**
409  * qib_ud_rcv - receive an incoming UD packet
410  * @ibp: the port 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 qib_qp_rcv() to process an incoming UD packet
418  * for the given QP.
419  * Called at interrupt level.
420  */
421 void qib_ud_rcv(struct qib_ibport *ibp, struct qib_ib_header *hdr,
422 		int has_grh, void *data, u32 tlen, struct qib_qp *qp)
423 {
424 	struct qib_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 
433 	/* Check for GRH */
434 	if (!has_grh) {
435 		ohdr = &hdr->u.oth;
436 		hdrsize = 8 + 12 + 8;   /* LRH + BTH + DETH */
437 	} else {
438 		ohdr = &hdr->u.l.oth;
439 		hdrsize = 8 + 40 + 12 + 8; /* LRH + GRH + BTH + DETH */
440 	}
441 	qkey = be32_to_cpu(ohdr->u.ud.deth[0]);
442 	src_qp = be32_to_cpu(ohdr->u.ud.deth[1]) & QIB_QPN_MASK;
443 
444 	/*
445 	 * Get the number of bytes the message was padded by
446 	 * and drop incomplete packets.
447 	 */
448 	pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
449 	if (unlikely(tlen < (hdrsize + pad + 4)))
450 		goto drop;
451 
452 	tlen -= hdrsize + pad + 4;
453 
454 	/*
455 	 * Check that the permissive LID is only used on QP0
456 	 * and the QKEY matches (see 9.6.1.4.1 and 9.6.1.5.1).
457 	 */
458 	if (qp->ibqp.qp_num) {
459 		if (unlikely(hdr->lrh[1] == IB_LID_PERMISSIVE ||
460 			     hdr->lrh[3] == IB_LID_PERMISSIVE))
461 			goto drop;
462 		if (qp->ibqp.qp_num > 1) {
463 			u16 pkey1, pkey2;
464 
465 			pkey1 = be32_to_cpu(ohdr->bth[0]);
466 			pkey2 = qib_get_pkey(ibp, qp->s_pkey_index);
467 			if (unlikely(!qib_pkey_ok(pkey1, pkey2))) {
468 				qib_bad_pqkey(ibp, IB_NOTICE_TRAP_BAD_PKEY,
469 					      pkey1,
470 					      (be16_to_cpu(hdr->lrh[0]) >> 4) &
471 						0xF,
472 					      src_qp, qp->ibqp.qp_num,
473 					      hdr->lrh[3], hdr->lrh[1]);
474 				return;
475 			}
476 		}
477 		if (unlikely(qkey != qp->qkey)) {
478 			qib_bad_pqkey(ibp, IB_NOTICE_TRAP_BAD_QKEY, qkey,
479 				      (be16_to_cpu(hdr->lrh[0]) >> 4) & 0xF,
480 				      src_qp, qp->ibqp.qp_num,
481 				      hdr->lrh[3], hdr->lrh[1]);
482 			return;
483 		}
484 		/* Drop invalid MAD packets (see 13.5.3.1). */
485 		if (unlikely(qp->ibqp.qp_num == 1 &&
486 			     (tlen != 256 ||
487 			      (be16_to_cpu(hdr->lrh[0]) >> 12) == 15)))
488 			goto drop;
489 	} else {
490 		struct ib_smp *smp;
491 
492 		/* Drop invalid MAD packets (see 13.5.3.1). */
493 		if (tlen != 256 || (be16_to_cpu(hdr->lrh[0]) >> 12) != 15)
494 			goto drop;
495 		smp = (struct ib_smp *) data;
496 		if ((hdr->lrh[1] == IB_LID_PERMISSIVE ||
497 		     hdr->lrh[3] == IB_LID_PERMISSIVE) &&
498 		    smp->mgmt_class != IB_MGMT_CLASS_SUBN_DIRECTED_ROUTE)
499 			goto drop;
500 	}
501 
502 	/*
503 	 * The opcode is in the low byte when its in network order
504 	 * (top byte when in host order).
505 	 */
506 	opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
507 	if (qp->ibqp.qp_num > 1 &&
508 	    opcode == IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE) {
509 		wc.ex.imm_data = ohdr->u.ud.imm_data;
510 		wc.wc_flags = IB_WC_WITH_IMM;
511 		tlen -= sizeof(u32);
512 	} else if (opcode == IB_OPCODE_UD_SEND_ONLY) {
513 		wc.ex.imm_data = 0;
514 		wc.wc_flags = 0;
515 	} else
516 		goto drop;
517 
518 	/*
519 	 * A GRH is expected to precede the data even if not
520 	 * present on the wire.
521 	 */
522 	wc.byte_len = tlen + sizeof(struct ib_grh);
523 
524 	/*
525 	 * Get the next work request entry to find where to put the data.
526 	 */
527 	if (qp->r_flags & QIB_R_REUSE_SGE)
528 		qp->r_flags &= ~QIB_R_REUSE_SGE;
529 	else {
530 		int ret;
531 
532 		ret = qib_get_rwqe(qp, 0);
533 		if (ret < 0) {
534 			qib_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
535 			return;
536 		}
537 		if (!ret) {
538 			if (qp->ibqp.qp_num == 0)
539 				ibp->n_vl15_dropped++;
540 			return;
541 		}
542 	}
543 	/* Silently drop packets which are too big. */
544 	if (unlikely(wc.byte_len > qp->r_len)) {
545 		qp->r_flags |= QIB_R_REUSE_SGE;
546 		goto drop;
547 	}
548 	if (has_grh) {
549 		qib_copy_sge(&qp->r_sge, &hdr->u.l.grh,
550 			     sizeof(struct ib_grh), 1);
551 		wc.wc_flags |= IB_WC_GRH;
552 	} else
553 		qib_skip_sge(&qp->r_sge, sizeof(struct ib_grh), 1);
554 	qib_copy_sge(&qp->r_sge, data, wc.byte_len - sizeof(struct ib_grh), 1);
555 	qib_put_ss(&qp->r_sge);
556 	if (!test_and_clear_bit(QIB_R_WRID_VALID, &qp->r_aflags))
557 		return;
558 	wc.wr_id = qp->r_wr_id;
559 	wc.status = IB_WC_SUCCESS;
560 	wc.opcode = IB_WC_RECV;
561 	wc.vendor_err = 0;
562 	wc.qp = &qp->ibqp;
563 	wc.src_qp = src_qp;
564 	wc.pkey_index = qp->ibqp.qp_type == IB_QPT_GSI ?
565 		qib_lookup_pkey(ibp, be32_to_cpu(ohdr->bth[0])) : 0;
566 	wc.slid = be16_to_cpu(hdr->lrh[3]);
567 	wc.sl = (be16_to_cpu(hdr->lrh[0]) >> 4) & 0xF;
568 	dlid = be16_to_cpu(hdr->lrh[1]);
569 	/*
570 	 * Save the LMC lower bits if the destination LID is a unicast LID.
571 	 */
572 	wc.dlid_path_bits = dlid >= QIB_MULTICAST_LID_BASE ? 0 :
573 		dlid & ((1 << ppd_from_ibp(ibp)->lmc) - 1);
574 	wc.port_num = qp->port_num;
575 	/* Signal completion event if the solicited bit is set. */
576 	qib_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
577 		     (ohdr->bth[0] &
578 			cpu_to_be32(IB_BTH_SOLICITED)) != 0);
579 	return;
580 
581 drop:
582 	ibp->n_pkt_drops++;
583 }
584