1 /*
2  *
3  * This file is provided under a dual BSD/GPLv2 license.  When using or
4  * redistributing this file, you may do so under either license.
5  *
6  * GPL LICENSE SUMMARY
7  *
8  * Copyright(c) 2015 Intel Corporation.
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of version 2 of the GNU General Public License as
12  * published by the Free Software Foundation.
13  *
14  * This program is distributed in the hope that it will be useful, but
15  * WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17  * General Public License for more details.
18  *
19  * BSD LICENSE
20  *
21  * Copyright(c) 2015 Intel Corporation.
22  *
23  * Redistribution and use in source and binary forms, with or without
24  * modification, are permitted provided that the following conditions
25  * are met:
26  *
27  *  - Redistributions of source code must retain the above copyright
28  *    notice, this list of conditions and the following disclaimer.
29  *  - Redistributions in binary form must reproduce the above copyright
30  *    notice, this list of conditions and the following disclaimer in
31  *    the documentation and/or other materials provided with the
32  *    distribution.
33  *  - Neither the name of Intel Corporation nor the names of its
34  *    contributors may be used to endorse or promote products derived
35  *    from this software without specific prior written permission.
36  *
37  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
38  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
39  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
40  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
41  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
42  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
43  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
44  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
45  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
46  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
47  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
48  *
49  */
50 
51 #include "hfi.h"
52 #include "sdma.h"
53 #include "qp.h"
54 
55 /* cut down ridiculously long IB macro names */
56 #define OP(x) IB_OPCODE_UC_##x
57 
58 /**
59  * hfi1_make_uc_req - construct a request packet (SEND, RDMA write)
60  * @qp: a pointer to the QP
61  *
62  * Return 1 if constructed; otherwise, return 0.
63  */
hfi1_make_uc_req(struct hfi1_qp * qp)64 int hfi1_make_uc_req(struct hfi1_qp *qp)
65 {
66 	struct hfi1_other_headers *ohdr;
67 	struct hfi1_swqe *wqe;
68 	unsigned long flags;
69 	u32 hwords = 5;
70 	u32 bth0 = 0;
71 	u32 len;
72 	u32 pmtu = qp->pmtu;
73 	int ret = 0;
74 	int middle = 0;
75 
76 	spin_lock_irqsave(&qp->s_lock, flags);
77 
78 	if (!(ib_hfi1_state_ops[qp->state] & HFI1_PROCESS_SEND_OK)) {
79 		if (!(ib_hfi1_state_ops[qp->state] & HFI1_FLUSH_SEND))
80 			goto bail;
81 		/* We are in the error state, flush the work request. */
82 		if (qp->s_last == qp->s_head)
83 			goto bail;
84 		/* If DMAs are in progress, we can't flush immediately. */
85 		if (atomic_read(&qp->s_iowait.sdma_busy)) {
86 			qp->s_flags |= HFI1_S_WAIT_DMA;
87 			goto bail;
88 		}
89 		clear_ahg(qp);
90 		wqe = get_swqe_ptr(qp, qp->s_last);
91 		hfi1_send_complete(qp, wqe, IB_WC_WR_FLUSH_ERR);
92 		goto done;
93 	}
94 
95 	ohdr = &qp->s_hdr->ibh.u.oth;
96 	if (qp->remote_ah_attr.ah_flags & IB_AH_GRH)
97 		ohdr = &qp->s_hdr->ibh.u.l.oth;
98 
99 	/* Get the next send request. */
100 	wqe = get_swqe_ptr(qp, qp->s_cur);
101 	qp->s_wqe = NULL;
102 	switch (qp->s_state) {
103 	default:
104 		if (!(ib_hfi1_state_ops[qp->state] &
105 		    HFI1_PROCESS_NEXT_SEND_OK))
106 			goto bail;
107 		/* Check if send work queue is empty. */
108 		if (qp->s_cur == qp->s_head) {
109 			clear_ahg(qp);
110 			goto bail;
111 		}
112 		/*
113 		 * Start a new request.
114 		 */
115 		wqe->psn = qp->s_next_psn;
116 		qp->s_psn = qp->s_next_psn;
117 		qp->s_sge.sge = wqe->sg_list[0];
118 		qp->s_sge.sg_list = wqe->sg_list + 1;
119 		qp->s_sge.num_sge = wqe->wr.num_sge;
120 		qp->s_sge.total_len = wqe->length;
121 		len = wqe->length;
122 		qp->s_len = len;
123 		switch (wqe->wr.opcode) {
124 		case IB_WR_SEND:
125 		case IB_WR_SEND_WITH_IMM:
126 			if (len > pmtu) {
127 				qp->s_state = OP(SEND_FIRST);
128 				len = pmtu;
129 				break;
130 			}
131 			if (wqe->wr.opcode == IB_WR_SEND)
132 				qp->s_state = OP(SEND_ONLY);
133 			else {
134 				qp->s_state =
135 					OP(SEND_ONLY_WITH_IMMEDIATE);
136 				/* Immediate data comes after the BTH */
137 				ohdr->u.imm_data = wqe->wr.ex.imm_data;
138 				hwords += 1;
139 			}
140 			if (wqe->wr.send_flags & IB_SEND_SOLICITED)
141 				bth0 |= IB_BTH_SOLICITED;
142 			qp->s_wqe = wqe;
143 			if (++qp->s_cur >= qp->s_size)
144 				qp->s_cur = 0;
145 			break;
146 
147 		case IB_WR_RDMA_WRITE:
148 		case IB_WR_RDMA_WRITE_WITH_IMM:
149 			ohdr->u.rc.reth.vaddr =
150 				cpu_to_be64(wqe->rdma_wr.remote_addr);
151 			ohdr->u.rc.reth.rkey =
152 				cpu_to_be32(wqe->rdma_wr.rkey);
153 			ohdr->u.rc.reth.length = cpu_to_be32(len);
154 			hwords += sizeof(struct ib_reth) / 4;
155 			if (len > pmtu) {
156 				qp->s_state = OP(RDMA_WRITE_FIRST);
157 				len = pmtu;
158 				break;
159 			}
160 			if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
161 				qp->s_state = OP(RDMA_WRITE_ONLY);
162 			else {
163 				qp->s_state =
164 					OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE);
165 				/* Immediate data comes after the RETH */
166 				ohdr->u.rc.imm_data = wqe->wr.ex.imm_data;
167 				hwords += 1;
168 				if (wqe->wr.send_flags & IB_SEND_SOLICITED)
169 					bth0 |= IB_BTH_SOLICITED;
170 			}
171 			qp->s_wqe = wqe;
172 			if (++qp->s_cur >= qp->s_size)
173 				qp->s_cur = 0;
174 			break;
175 
176 		default:
177 			goto bail;
178 		}
179 		break;
180 
181 	case OP(SEND_FIRST):
182 		qp->s_state = OP(SEND_MIDDLE);
183 		/* FALLTHROUGH */
184 	case OP(SEND_MIDDLE):
185 		len = qp->s_len;
186 		if (len > pmtu) {
187 			len = pmtu;
188 			middle = HFI1_CAP_IS_KSET(SDMA_AHG);
189 			break;
190 		}
191 		if (wqe->wr.opcode == IB_WR_SEND)
192 			qp->s_state = OP(SEND_LAST);
193 		else {
194 			qp->s_state = OP(SEND_LAST_WITH_IMMEDIATE);
195 			/* Immediate data comes after the BTH */
196 			ohdr->u.imm_data = wqe->wr.ex.imm_data;
197 			hwords += 1;
198 		}
199 		if (wqe->wr.send_flags & IB_SEND_SOLICITED)
200 			bth0 |= IB_BTH_SOLICITED;
201 		qp->s_wqe = wqe;
202 		if (++qp->s_cur >= qp->s_size)
203 			qp->s_cur = 0;
204 		break;
205 
206 	case OP(RDMA_WRITE_FIRST):
207 		qp->s_state = OP(RDMA_WRITE_MIDDLE);
208 		/* FALLTHROUGH */
209 	case OP(RDMA_WRITE_MIDDLE):
210 		len = qp->s_len;
211 		if (len > pmtu) {
212 			len = pmtu;
213 			middle = HFI1_CAP_IS_KSET(SDMA_AHG);
214 			break;
215 		}
216 		if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
217 			qp->s_state = OP(RDMA_WRITE_LAST);
218 		else {
219 			qp->s_state =
220 				OP(RDMA_WRITE_LAST_WITH_IMMEDIATE);
221 			/* Immediate data comes after the BTH */
222 			ohdr->u.imm_data = wqe->wr.ex.imm_data;
223 			hwords += 1;
224 			if (wqe->wr.send_flags & IB_SEND_SOLICITED)
225 				bth0 |= IB_BTH_SOLICITED;
226 		}
227 		qp->s_wqe = wqe;
228 		if (++qp->s_cur >= qp->s_size)
229 			qp->s_cur = 0;
230 		break;
231 	}
232 	qp->s_len -= len;
233 	qp->s_hdrwords = hwords;
234 	qp->s_cur_sge = &qp->s_sge;
235 	qp->s_cur_size = len;
236 	hfi1_make_ruc_header(qp, ohdr, bth0 | (qp->s_state << 24),
237 			     mask_psn(qp->s_next_psn++), middle);
238 done:
239 	ret = 1;
240 	goto unlock;
241 
242 bail:
243 	qp->s_flags &= ~HFI1_S_BUSY;
244 unlock:
245 	spin_unlock_irqrestore(&qp->s_lock, flags);
246 	return ret;
247 }
248 
249 /**
250  * hfi1_uc_rcv - handle an incoming UC packet
251  * @ibp: the port the packet came in on
252  * @hdr: the header of the packet
253  * @rcv_flags: flags relevant to rcv processing
254  * @data: the packet data
255  * @tlen: the length of the packet
256  * @qp: the QP for this packet.
257  *
258  * This is called from qp_rcv() to process an incoming UC packet
259  * for the given QP.
260  * Called at interrupt level.
261  */
hfi1_uc_rcv(struct hfi1_packet * packet)262 void hfi1_uc_rcv(struct hfi1_packet *packet)
263 {
264 	struct hfi1_ibport *ibp = &packet->rcd->ppd->ibport_data;
265 	struct hfi1_ib_header *hdr = packet->hdr;
266 	u32 rcv_flags = packet->rcv_flags;
267 	void *data = packet->ebuf;
268 	u32 tlen = packet->tlen;
269 	struct hfi1_qp *qp = packet->qp;
270 	struct hfi1_other_headers *ohdr = packet->ohdr;
271 	u32 opcode;
272 	u32 hdrsize = packet->hlen;
273 	u32 psn;
274 	u32 pad;
275 	struct ib_wc wc;
276 	u32 pmtu = qp->pmtu;
277 	struct ib_reth *reth;
278 	int has_grh = rcv_flags & HFI1_HAS_GRH;
279 	int ret;
280 	u32 bth1;
281 	struct ib_grh *grh = NULL;
282 
283 	opcode = be32_to_cpu(ohdr->bth[0]);
284 	if (hfi1_ruc_check_hdr(ibp, hdr, has_grh, qp, opcode))
285 		return;
286 
287 	bth1 = be32_to_cpu(ohdr->bth[1]);
288 	if (unlikely(bth1 & (HFI1_BECN_SMASK | HFI1_FECN_SMASK))) {
289 		if (bth1 & HFI1_BECN_SMASK) {
290 			struct hfi1_pportdata *ppd = ppd_from_ibp(ibp);
291 			u32 rqpn, lqpn;
292 			u16 rlid = be16_to_cpu(hdr->lrh[3]);
293 			u8 sl, sc5;
294 
295 			lqpn = bth1 & HFI1_QPN_MASK;
296 			rqpn = qp->remote_qpn;
297 
298 			sc5 = ibp->sl_to_sc[qp->remote_ah_attr.sl];
299 			sl = ibp->sc_to_sl[sc5];
300 
301 			process_becn(ppd, sl, rlid, lqpn, rqpn,
302 					IB_CC_SVCTYPE_UC);
303 		}
304 
305 		if (bth1 & HFI1_FECN_SMASK) {
306 			u16 pkey = (u16)be32_to_cpu(ohdr->bth[0]);
307 			u16 slid = be16_to_cpu(hdr->lrh[3]);
308 			u16 dlid = be16_to_cpu(hdr->lrh[1]);
309 			u32 src_qp = qp->remote_qpn;
310 			u8 sc5;
311 
312 			sc5 = ibp->sl_to_sc[qp->remote_ah_attr.sl];
313 
314 			return_cnp(ibp, qp, src_qp, pkey, dlid, slid, sc5, grh);
315 		}
316 	}
317 
318 	psn = be32_to_cpu(ohdr->bth[2]);
319 	opcode >>= 24;
320 
321 	/* Compare the PSN verses the expected PSN. */
322 	if (unlikely(cmp_psn(psn, qp->r_psn) != 0)) {
323 		/*
324 		 * Handle a sequence error.
325 		 * Silently drop any current message.
326 		 */
327 		qp->r_psn = psn;
328 inv:
329 		if (qp->r_state == OP(SEND_FIRST) ||
330 		    qp->r_state == OP(SEND_MIDDLE)) {
331 			set_bit(HFI1_R_REWIND_SGE, &qp->r_aflags);
332 			qp->r_sge.num_sge = 0;
333 		} else
334 			hfi1_put_ss(&qp->r_sge);
335 		qp->r_state = OP(SEND_LAST);
336 		switch (opcode) {
337 		case OP(SEND_FIRST):
338 		case OP(SEND_ONLY):
339 		case OP(SEND_ONLY_WITH_IMMEDIATE):
340 			goto send_first;
341 
342 		case OP(RDMA_WRITE_FIRST):
343 		case OP(RDMA_WRITE_ONLY):
344 		case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE):
345 			goto rdma_first;
346 
347 		default:
348 			goto drop;
349 		}
350 	}
351 
352 	/* Check for opcode sequence errors. */
353 	switch (qp->r_state) {
354 	case OP(SEND_FIRST):
355 	case OP(SEND_MIDDLE):
356 		if (opcode == OP(SEND_MIDDLE) ||
357 		    opcode == OP(SEND_LAST) ||
358 		    opcode == OP(SEND_LAST_WITH_IMMEDIATE))
359 			break;
360 		goto inv;
361 
362 	case OP(RDMA_WRITE_FIRST):
363 	case OP(RDMA_WRITE_MIDDLE):
364 		if (opcode == OP(RDMA_WRITE_MIDDLE) ||
365 		    opcode == OP(RDMA_WRITE_LAST) ||
366 		    opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
367 			break;
368 		goto inv;
369 
370 	default:
371 		if (opcode == OP(SEND_FIRST) ||
372 		    opcode == OP(SEND_ONLY) ||
373 		    opcode == OP(SEND_ONLY_WITH_IMMEDIATE) ||
374 		    opcode == OP(RDMA_WRITE_FIRST) ||
375 		    opcode == OP(RDMA_WRITE_ONLY) ||
376 		    opcode == OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE))
377 			break;
378 		goto inv;
379 	}
380 
381 	if (qp->state == IB_QPS_RTR && !(qp->r_flags & HFI1_R_COMM_EST))
382 		qp_comm_est(qp);
383 
384 	/* OK, process the packet. */
385 	switch (opcode) {
386 	case OP(SEND_FIRST):
387 	case OP(SEND_ONLY):
388 	case OP(SEND_ONLY_WITH_IMMEDIATE):
389 send_first:
390 		if (test_and_clear_bit(HFI1_R_REWIND_SGE, &qp->r_aflags))
391 			qp->r_sge = qp->s_rdma_read_sge;
392 		else {
393 			ret = hfi1_get_rwqe(qp, 0);
394 			if (ret < 0)
395 				goto op_err;
396 			if (!ret)
397 				goto drop;
398 			/*
399 			 * qp->s_rdma_read_sge will be the owner
400 			 * of the mr references.
401 			 */
402 			qp->s_rdma_read_sge = qp->r_sge;
403 		}
404 		qp->r_rcv_len = 0;
405 		if (opcode == OP(SEND_ONLY))
406 			goto no_immediate_data;
407 		else if (opcode == OP(SEND_ONLY_WITH_IMMEDIATE))
408 			goto send_last_imm;
409 		/* FALLTHROUGH */
410 	case OP(SEND_MIDDLE):
411 		/* Check for invalid length PMTU or posted rwqe len. */
412 		if (unlikely(tlen != (hdrsize + pmtu + 4)))
413 			goto rewind;
414 		qp->r_rcv_len += pmtu;
415 		if (unlikely(qp->r_rcv_len > qp->r_len))
416 			goto rewind;
417 		hfi1_copy_sge(&qp->r_sge, data, pmtu, 0);
418 		break;
419 
420 	case OP(SEND_LAST_WITH_IMMEDIATE):
421 send_last_imm:
422 		wc.ex.imm_data = ohdr->u.imm_data;
423 		wc.wc_flags = IB_WC_WITH_IMM;
424 		goto send_last;
425 	case OP(SEND_LAST):
426 no_immediate_data:
427 		wc.ex.imm_data = 0;
428 		wc.wc_flags = 0;
429 send_last:
430 		/* Get the number of bytes the message was padded by. */
431 		pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
432 		/* Check for invalid length. */
433 		/* LAST len should be >= 1 */
434 		if (unlikely(tlen < (hdrsize + pad + 4)))
435 			goto rewind;
436 		/* Don't count the CRC. */
437 		tlen -= (hdrsize + pad + 4);
438 		wc.byte_len = tlen + qp->r_rcv_len;
439 		if (unlikely(wc.byte_len > qp->r_len))
440 			goto rewind;
441 		wc.opcode = IB_WC_RECV;
442 		hfi1_copy_sge(&qp->r_sge, data, tlen, 0);
443 		hfi1_put_ss(&qp->s_rdma_read_sge);
444 last_imm:
445 		wc.wr_id = qp->r_wr_id;
446 		wc.status = IB_WC_SUCCESS;
447 		wc.qp = &qp->ibqp;
448 		wc.src_qp = qp->remote_qpn;
449 		wc.slid = qp->remote_ah_attr.dlid;
450 		/*
451 		 * It seems that IB mandates the presence of an SL in a
452 		 * work completion only for the UD transport (see section
453 		 * 11.4.2 of IBTA Vol. 1).
454 		 *
455 		 * However, the way the SL is chosen below is consistent
456 		 * with the way that IB/qib works and is trying avoid
457 		 * introducing incompatibilities.
458 		 *
459 		 * See also OPA Vol. 1, section 9.7.6, and table 9-17.
460 		 */
461 		wc.sl = qp->remote_ah_attr.sl;
462 		/* zero fields that are N/A */
463 		wc.vendor_err = 0;
464 		wc.pkey_index = 0;
465 		wc.dlid_path_bits = 0;
466 		wc.port_num = 0;
467 		/* Signal completion event if the solicited bit is set. */
468 		hfi1_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
469 			      (ohdr->bth[0] &
470 				cpu_to_be32(IB_BTH_SOLICITED)) != 0);
471 		break;
472 
473 	case OP(RDMA_WRITE_FIRST):
474 	case OP(RDMA_WRITE_ONLY):
475 	case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE): /* consume RWQE */
476 rdma_first:
477 		if (unlikely(!(qp->qp_access_flags &
478 			       IB_ACCESS_REMOTE_WRITE))) {
479 			goto drop;
480 		}
481 		reth = &ohdr->u.rc.reth;
482 		qp->r_len = be32_to_cpu(reth->length);
483 		qp->r_rcv_len = 0;
484 		qp->r_sge.sg_list = NULL;
485 		if (qp->r_len != 0) {
486 			u32 rkey = be32_to_cpu(reth->rkey);
487 			u64 vaddr = be64_to_cpu(reth->vaddr);
488 			int ok;
489 
490 			/* Check rkey */
491 			ok = hfi1_rkey_ok(qp, &qp->r_sge.sge, qp->r_len,
492 					  vaddr, rkey, IB_ACCESS_REMOTE_WRITE);
493 			if (unlikely(!ok))
494 				goto drop;
495 			qp->r_sge.num_sge = 1;
496 		} else {
497 			qp->r_sge.num_sge = 0;
498 			qp->r_sge.sge.mr = NULL;
499 			qp->r_sge.sge.vaddr = NULL;
500 			qp->r_sge.sge.length = 0;
501 			qp->r_sge.sge.sge_length = 0;
502 		}
503 		if (opcode == OP(RDMA_WRITE_ONLY))
504 			goto rdma_last;
505 		else if (opcode == OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE)) {
506 			wc.ex.imm_data = ohdr->u.rc.imm_data;
507 			goto rdma_last_imm;
508 		}
509 		/* FALLTHROUGH */
510 	case OP(RDMA_WRITE_MIDDLE):
511 		/* Check for invalid length PMTU or posted rwqe len. */
512 		if (unlikely(tlen != (hdrsize + pmtu + 4)))
513 			goto drop;
514 		qp->r_rcv_len += pmtu;
515 		if (unlikely(qp->r_rcv_len > qp->r_len))
516 			goto drop;
517 		hfi1_copy_sge(&qp->r_sge, data, pmtu, 1);
518 		break;
519 
520 	case OP(RDMA_WRITE_LAST_WITH_IMMEDIATE):
521 		wc.ex.imm_data = ohdr->u.imm_data;
522 rdma_last_imm:
523 		wc.wc_flags = IB_WC_WITH_IMM;
524 
525 		/* Get the number of bytes the message was padded by. */
526 		pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
527 		/* Check for invalid length. */
528 		/* LAST len should be >= 1 */
529 		if (unlikely(tlen < (hdrsize + pad + 4)))
530 			goto drop;
531 		/* Don't count the CRC. */
532 		tlen -= (hdrsize + pad + 4);
533 		if (unlikely(tlen + qp->r_rcv_len != qp->r_len))
534 			goto drop;
535 		if (test_and_clear_bit(HFI1_R_REWIND_SGE, &qp->r_aflags))
536 			hfi1_put_ss(&qp->s_rdma_read_sge);
537 		else {
538 			ret = hfi1_get_rwqe(qp, 1);
539 			if (ret < 0)
540 				goto op_err;
541 			if (!ret)
542 				goto drop;
543 		}
544 		wc.byte_len = qp->r_len;
545 		wc.opcode = IB_WC_RECV_RDMA_WITH_IMM;
546 		hfi1_copy_sge(&qp->r_sge, data, tlen, 1);
547 		hfi1_put_ss(&qp->r_sge);
548 		goto last_imm;
549 
550 	case OP(RDMA_WRITE_LAST):
551 rdma_last:
552 		/* Get the number of bytes the message was padded by. */
553 		pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
554 		/* Check for invalid length. */
555 		/* LAST len should be >= 1 */
556 		if (unlikely(tlen < (hdrsize + pad + 4)))
557 			goto drop;
558 		/* Don't count the CRC. */
559 		tlen -= (hdrsize + pad + 4);
560 		if (unlikely(tlen + qp->r_rcv_len != qp->r_len))
561 			goto drop;
562 		hfi1_copy_sge(&qp->r_sge, data, tlen, 1);
563 		hfi1_put_ss(&qp->r_sge);
564 		break;
565 
566 	default:
567 		/* Drop packet for unknown opcodes. */
568 		goto drop;
569 	}
570 	qp->r_psn++;
571 	qp->r_state = opcode;
572 	return;
573 
574 rewind:
575 	set_bit(HFI1_R_REWIND_SGE, &qp->r_aflags);
576 	qp->r_sge.num_sge = 0;
577 drop:
578 	ibp->n_pkt_drops++;
579 	return;
580 
581 op_err:
582 	hfi1_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
583 	return;
584 
585 }
586