xref: /openbmc/linux/drivers/infiniband/hw/hfi1/uc.c (revision 8e694cd2)
1 /*
2  * Copyright(c) 2015, 2016 Intel Corporation.
3  *
4  * This file is provided under a dual BSD/GPLv2 license.  When using or
5  * redistributing this file, you may do so under either license.
6  *
7  * GPL LICENSE SUMMARY
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of version 2 of the GNU General Public License as
11  * published by the Free Software Foundation.
12  *
13  * This program is distributed in the hope that it will be useful, but
14  * WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16  * General Public License for more details.
17  *
18  * BSD LICENSE
19  *
20  * Redistribution and use in source and binary forms, with or without
21  * modification, are permitted provided that the following conditions
22  * are met:
23  *
24  *  - Redistributions of source code must retain the above copyright
25  *    notice, this list of conditions and the following disclaimer.
26  *  - Redistributions in binary form must reproduce the above copyright
27  *    notice, this list of conditions and the following disclaimer in
28  *    the documentation and/or other materials provided with the
29  *    distribution.
30  *  - Neither the name of Intel Corporation nor the names of its
31  *    contributors may be used to endorse or promote products derived
32  *    from this software without specific prior written permission.
33  *
34  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
35  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
36  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
37  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
38  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
39  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
40  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
41  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
42  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
43  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
44  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
45  *
46  */
47 
48 #include "hfi.h"
49 #include "verbs_txreq.h"
50 #include "qp.h"
51 
52 /* cut down ridiculously long IB macro names */
53 #define OP(x) IB_OPCODE_UC_##x
54 
55 /* only opcode mask for adaptive pio */
56 const u32 uc_only_opcode =
57 	BIT(OP(SEND_ONLY) & 0x1f) |
58 	BIT(OP(SEND_ONLY_WITH_IMMEDIATE & 0x1f)) |
59 	BIT(OP(RDMA_WRITE_ONLY & 0x1f)) |
60 	BIT(OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE & 0x1f));
61 
62 /**
63  * hfi1_make_uc_req - construct a request packet (SEND, RDMA write)
64  * @qp: a pointer to the QP
65  *
66  * Assume s_lock is held.
67  *
68  * Return 1 if constructed; otherwise, return 0.
69  */
70 int hfi1_make_uc_req(struct rvt_qp *qp, struct hfi1_pkt_state *ps)
71 {
72 	struct hfi1_qp_priv *priv = qp->priv;
73 	struct hfi1_other_headers *ohdr;
74 	struct rvt_swqe *wqe;
75 	u32 hwords = 5;
76 	u32 bth0 = 0;
77 	u32 len;
78 	u32 pmtu = qp->pmtu;
79 	int middle = 0;
80 
81 	ps->s_txreq = get_txreq(ps->dev, qp);
82 	if (IS_ERR(ps->s_txreq))
83 		goto bail_no_tx;
84 
85 	if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_SEND_OK)) {
86 		if (!(ib_rvt_state_ops[qp->state] & RVT_FLUSH_SEND))
87 			goto bail;
88 		/* We are in the error state, flush the work request. */
89 		smp_read_barrier_depends(); /* see post_one_send() */
90 		if (qp->s_last == ACCESS_ONCE(qp->s_head))
91 			goto bail;
92 		/* If DMAs are in progress, we can't flush immediately. */
93 		if (iowait_sdma_pending(&priv->s_iowait)) {
94 			qp->s_flags |= RVT_S_WAIT_DMA;
95 			goto bail;
96 		}
97 		clear_ahg(qp);
98 		wqe = rvt_get_swqe_ptr(qp, qp->s_last);
99 		hfi1_send_complete(qp, wqe, IB_WC_WR_FLUSH_ERR);
100 		goto done_free_tx;
101 	}
102 
103 	ohdr = &ps->s_txreq->phdr.hdr.u.oth;
104 	if (qp->remote_ah_attr.ah_flags & IB_AH_GRH)
105 		ohdr = &ps->s_txreq->phdr.hdr.u.l.oth;
106 
107 	/* Get the next send request. */
108 	wqe = rvt_get_swqe_ptr(qp, qp->s_cur);
109 	qp->s_wqe = NULL;
110 	switch (qp->s_state) {
111 	default:
112 		if (!(ib_rvt_state_ops[qp->state] &
113 		    RVT_PROCESS_NEXT_SEND_OK))
114 			goto bail;
115 		/* Check if send work queue is empty. */
116 		smp_read_barrier_depends(); /* see post_one_send() */
117 		if (qp->s_cur == ACCESS_ONCE(qp->s_head)) {
118 			clear_ahg(qp);
119 			goto bail;
120 		}
121 		/*
122 		 * Start a new request.
123 		 */
124 		qp->s_psn = wqe->psn;
125 		qp->s_sge.sge = wqe->sg_list[0];
126 		qp->s_sge.sg_list = wqe->sg_list + 1;
127 		qp->s_sge.num_sge = wqe->wr.num_sge;
128 		qp->s_sge.total_len = wqe->length;
129 		len = wqe->length;
130 		qp->s_len = len;
131 		switch (wqe->wr.opcode) {
132 		case IB_WR_SEND:
133 		case IB_WR_SEND_WITH_IMM:
134 			if (len > pmtu) {
135 				qp->s_state = OP(SEND_FIRST);
136 				len = pmtu;
137 				break;
138 			}
139 			if (wqe->wr.opcode == IB_WR_SEND) {
140 				qp->s_state = OP(SEND_ONLY);
141 			} else {
142 				qp->s_state =
143 					OP(SEND_ONLY_WITH_IMMEDIATE);
144 				/* Immediate data comes after the BTH */
145 				ohdr->u.imm_data = wqe->wr.ex.imm_data;
146 				hwords += 1;
147 			}
148 			if (wqe->wr.send_flags & IB_SEND_SOLICITED)
149 				bth0 |= IB_BTH_SOLICITED;
150 			qp->s_wqe = wqe;
151 			if (++qp->s_cur >= qp->s_size)
152 				qp->s_cur = 0;
153 			break;
154 
155 		case IB_WR_RDMA_WRITE:
156 		case IB_WR_RDMA_WRITE_WITH_IMM:
157 			ohdr->u.rc.reth.vaddr =
158 				cpu_to_be64(wqe->rdma_wr.remote_addr);
159 			ohdr->u.rc.reth.rkey =
160 				cpu_to_be32(wqe->rdma_wr.rkey);
161 			ohdr->u.rc.reth.length = cpu_to_be32(len);
162 			hwords += sizeof(struct ib_reth) / 4;
163 			if (len > pmtu) {
164 				qp->s_state = OP(RDMA_WRITE_FIRST);
165 				len = pmtu;
166 				break;
167 			}
168 			if (wqe->wr.opcode == IB_WR_RDMA_WRITE) {
169 				qp->s_state = OP(RDMA_WRITE_ONLY);
170 			} else {
171 				qp->s_state =
172 					OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE);
173 				/* Immediate data comes after the RETH */
174 				ohdr->u.rc.imm_data = wqe->wr.ex.imm_data;
175 				hwords += 1;
176 				if (wqe->wr.send_flags & IB_SEND_SOLICITED)
177 					bth0 |= IB_BTH_SOLICITED;
178 			}
179 			qp->s_wqe = wqe;
180 			if (++qp->s_cur >= qp->s_size)
181 				qp->s_cur = 0;
182 			break;
183 
184 		default:
185 			goto bail;
186 		}
187 		break;
188 
189 	case OP(SEND_FIRST):
190 		qp->s_state = OP(SEND_MIDDLE);
191 		/* FALLTHROUGH */
192 	case OP(SEND_MIDDLE):
193 		len = qp->s_len;
194 		if (len > pmtu) {
195 			len = pmtu;
196 			middle = HFI1_CAP_IS_KSET(SDMA_AHG);
197 			break;
198 		}
199 		if (wqe->wr.opcode == IB_WR_SEND) {
200 			qp->s_state = OP(SEND_LAST);
201 		} else {
202 			qp->s_state = OP(SEND_LAST_WITH_IMMEDIATE);
203 			/* Immediate data comes after the BTH */
204 			ohdr->u.imm_data = wqe->wr.ex.imm_data;
205 			hwords += 1;
206 		}
207 		if (wqe->wr.send_flags & IB_SEND_SOLICITED)
208 			bth0 |= IB_BTH_SOLICITED;
209 		qp->s_wqe = wqe;
210 		if (++qp->s_cur >= qp->s_size)
211 			qp->s_cur = 0;
212 		break;
213 
214 	case OP(RDMA_WRITE_FIRST):
215 		qp->s_state = OP(RDMA_WRITE_MIDDLE);
216 		/* FALLTHROUGH */
217 	case OP(RDMA_WRITE_MIDDLE):
218 		len = qp->s_len;
219 		if (len > pmtu) {
220 			len = pmtu;
221 			middle = HFI1_CAP_IS_KSET(SDMA_AHG);
222 			break;
223 		}
224 		if (wqe->wr.opcode == IB_WR_RDMA_WRITE) {
225 			qp->s_state = OP(RDMA_WRITE_LAST);
226 		} else {
227 			qp->s_state =
228 				OP(RDMA_WRITE_LAST_WITH_IMMEDIATE);
229 			/* Immediate data comes after the BTH */
230 			ohdr->u.imm_data = wqe->wr.ex.imm_data;
231 			hwords += 1;
232 			if (wqe->wr.send_flags & IB_SEND_SOLICITED)
233 				bth0 |= IB_BTH_SOLICITED;
234 		}
235 		qp->s_wqe = wqe;
236 		if (++qp->s_cur >= qp->s_size)
237 			qp->s_cur = 0;
238 		break;
239 	}
240 	qp->s_len -= len;
241 	qp->s_hdrwords = hwords;
242 	ps->s_txreq->sde = priv->s_sde;
243 	qp->s_cur_sge = &qp->s_sge;
244 	qp->s_cur_size = len;
245 	hfi1_make_ruc_header(qp, ohdr, bth0 | (qp->s_state << 24),
246 			     mask_psn(qp->s_psn++), middle, ps);
247 	/* pbc */
248 	ps->s_txreq->hdr_dwords = qp->s_hdrwords + 2;
249 	return 1;
250 
251 done_free_tx:
252 	hfi1_put_txreq(ps->s_txreq);
253 	ps->s_txreq = NULL;
254 	return 1;
255 
256 bail:
257 	hfi1_put_txreq(ps->s_txreq);
258 
259 bail_no_tx:
260 	ps->s_txreq = NULL;
261 	qp->s_flags &= ~RVT_S_BUSY;
262 	qp->s_hdrwords = 0;
263 	return 0;
264 }
265 
266 /**
267  * hfi1_uc_rcv - handle an incoming UC packet
268  * @ibp: the port the packet came in on
269  * @hdr: the header of the packet
270  * @rcv_flags: flags relevant to rcv processing
271  * @data: the packet data
272  * @tlen: the length of the packet
273  * @qp: the QP for this packet.
274  *
275  * This is called from qp_rcv() to process an incoming UC packet
276  * for the given QP.
277  * Called at interrupt level.
278  */
279 void hfi1_uc_rcv(struct hfi1_packet *packet)
280 {
281 	struct hfi1_ibport *ibp = &packet->rcd->ppd->ibport_data;
282 	struct hfi1_ib_header *hdr = packet->hdr;
283 	u32 rcv_flags = packet->rcv_flags;
284 	void *data = packet->ebuf;
285 	u32 tlen = packet->tlen;
286 	struct rvt_qp *qp = packet->qp;
287 	struct hfi1_other_headers *ohdr = packet->ohdr;
288 	u32 bth0, opcode;
289 	u32 hdrsize = packet->hlen;
290 	u32 psn;
291 	u32 pad;
292 	struct ib_wc wc;
293 	u32 pmtu = qp->pmtu;
294 	struct ib_reth *reth;
295 	int has_grh = rcv_flags & HFI1_HAS_GRH;
296 	int ret;
297 	u32 bth1;
298 
299 	bth0 = be32_to_cpu(ohdr->bth[0]);
300 	if (hfi1_ruc_check_hdr(ibp, hdr, has_grh, qp, bth0))
301 		return;
302 
303 	bth1 = be32_to_cpu(ohdr->bth[1]);
304 	if (unlikely(bth1 & (HFI1_BECN_SMASK | HFI1_FECN_SMASK))) {
305 		if (bth1 & HFI1_BECN_SMASK) {
306 			struct hfi1_pportdata *ppd = ppd_from_ibp(ibp);
307 			u32 rqpn, lqpn;
308 			u16 rlid = be16_to_cpu(hdr->lrh[3]);
309 			u8 sl, sc5;
310 
311 			lqpn = bth1 & RVT_QPN_MASK;
312 			rqpn = qp->remote_qpn;
313 
314 			sc5 = ibp->sl_to_sc[qp->remote_ah_attr.sl];
315 			sl = ibp->sc_to_sl[sc5];
316 
317 			process_becn(ppd, sl, rlid, lqpn, rqpn,
318 				     IB_CC_SVCTYPE_UC);
319 		}
320 
321 		if (bth1 & HFI1_FECN_SMASK) {
322 			struct ib_grh *grh = NULL;
323 			u16 pkey = (u16)be32_to_cpu(ohdr->bth[0]);
324 			u16 slid = be16_to_cpu(hdr->lrh[3]);
325 			u16 dlid = be16_to_cpu(hdr->lrh[1]);
326 			u32 src_qp = qp->remote_qpn;
327 			u8 sc5;
328 
329 			sc5 = ibp->sl_to_sc[qp->remote_ah_attr.sl];
330 			if (has_grh)
331 				grh = &hdr->u.l.grh;
332 
333 			return_cnp(ibp, qp, src_qp, pkey, dlid, slid, sc5,
334 				   grh);
335 		}
336 	}
337 
338 	psn = be32_to_cpu(ohdr->bth[2]);
339 	opcode = (bth0 >> 24) & 0xff;
340 
341 	/* Compare the PSN verses the expected PSN. */
342 	if (unlikely(cmp_psn(psn, qp->r_psn) != 0)) {
343 		/*
344 		 * Handle a sequence error.
345 		 * Silently drop any current message.
346 		 */
347 		qp->r_psn = psn;
348 inv:
349 		if (qp->r_state == OP(SEND_FIRST) ||
350 		    qp->r_state == OP(SEND_MIDDLE)) {
351 			set_bit(RVT_R_REWIND_SGE, &qp->r_aflags);
352 			qp->r_sge.num_sge = 0;
353 		} else {
354 			rvt_put_ss(&qp->r_sge);
355 		}
356 		qp->r_state = OP(SEND_LAST);
357 		switch (opcode) {
358 		case OP(SEND_FIRST):
359 		case OP(SEND_ONLY):
360 		case OP(SEND_ONLY_WITH_IMMEDIATE):
361 			goto send_first;
362 
363 		case OP(RDMA_WRITE_FIRST):
364 		case OP(RDMA_WRITE_ONLY):
365 		case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE):
366 			goto rdma_first;
367 
368 		default:
369 			goto drop;
370 		}
371 	}
372 
373 	/* Check for opcode sequence errors. */
374 	switch (qp->r_state) {
375 	case OP(SEND_FIRST):
376 	case OP(SEND_MIDDLE):
377 		if (opcode == OP(SEND_MIDDLE) ||
378 		    opcode == OP(SEND_LAST) ||
379 		    opcode == OP(SEND_LAST_WITH_IMMEDIATE))
380 			break;
381 		goto inv;
382 
383 	case OP(RDMA_WRITE_FIRST):
384 	case OP(RDMA_WRITE_MIDDLE):
385 		if (opcode == OP(RDMA_WRITE_MIDDLE) ||
386 		    opcode == OP(RDMA_WRITE_LAST) ||
387 		    opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
388 			break;
389 		goto inv;
390 
391 	default:
392 		if (opcode == OP(SEND_FIRST) ||
393 		    opcode == OP(SEND_ONLY) ||
394 		    opcode == OP(SEND_ONLY_WITH_IMMEDIATE) ||
395 		    opcode == OP(RDMA_WRITE_FIRST) ||
396 		    opcode == OP(RDMA_WRITE_ONLY) ||
397 		    opcode == OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE))
398 			break;
399 		goto inv;
400 	}
401 
402 	if (qp->state == IB_QPS_RTR && !(qp->r_flags & RVT_R_COMM_EST))
403 		qp_comm_est(qp);
404 
405 	/* OK, process the packet. */
406 	switch (opcode) {
407 	case OP(SEND_FIRST):
408 	case OP(SEND_ONLY):
409 	case OP(SEND_ONLY_WITH_IMMEDIATE):
410 send_first:
411 		if (test_and_clear_bit(RVT_R_REWIND_SGE, &qp->r_aflags)) {
412 			qp->r_sge = qp->s_rdma_read_sge;
413 		} else {
414 			ret = hfi1_rvt_get_rwqe(qp, 0);
415 			if (ret < 0)
416 				goto op_err;
417 			if (!ret)
418 				goto drop;
419 			/*
420 			 * qp->s_rdma_read_sge will be the owner
421 			 * of the mr references.
422 			 */
423 			qp->s_rdma_read_sge = qp->r_sge;
424 		}
425 		qp->r_rcv_len = 0;
426 		if (opcode == OP(SEND_ONLY))
427 			goto no_immediate_data;
428 		else if (opcode == OP(SEND_ONLY_WITH_IMMEDIATE))
429 			goto send_last_imm;
430 		/* FALLTHROUGH */
431 	case OP(SEND_MIDDLE):
432 		/* Check for invalid length PMTU or posted rwqe len. */
433 		if (unlikely(tlen != (hdrsize + pmtu + 4)))
434 			goto rewind;
435 		qp->r_rcv_len += pmtu;
436 		if (unlikely(qp->r_rcv_len > qp->r_len))
437 			goto rewind;
438 		hfi1_copy_sge(&qp->r_sge, data, pmtu, 0, 0);
439 		break;
440 
441 	case OP(SEND_LAST_WITH_IMMEDIATE):
442 send_last_imm:
443 		wc.ex.imm_data = ohdr->u.imm_data;
444 		wc.wc_flags = IB_WC_WITH_IMM;
445 		goto send_last;
446 	case OP(SEND_LAST):
447 no_immediate_data:
448 		wc.ex.imm_data = 0;
449 		wc.wc_flags = 0;
450 send_last:
451 		/* Get the number of bytes the message was padded by. */
452 		pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
453 		/* Check for invalid length. */
454 		/* LAST len should be >= 1 */
455 		if (unlikely(tlen < (hdrsize + pad + 4)))
456 			goto rewind;
457 		/* Don't count the CRC. */
458 		tlen -= (hdrsize + pad + 4);
459 		wc.byte_len = tlen + qp->r_rcv_len;
460 		if (unlikely(wc.byte_len > qp->r_len))
461 			goto rewind;
462 		wc.opcode = IB_WC_RECV;
463 		hfi1_copy_sge(&qp->r_sge, data, tlen, 0, 0);
464 		rvt_put_ss(&qp->s_rdma_read_sge);
465 last_imm:
466 		wc.wr_id = qp->r_wr_id;
467 		wc.status = IB_WC_SUCCESS;
468 		wc.qp = &qp->ibqp;
469 		wc.src_qp = qp->remote_qpn;
470 		wc.slid = qp->remote_ah_attr.dlid;
471 		/*
472 		 * It seems that IB mandates the presence of an SL in a
473 		 * work completion only for the UD transport (see section
474 		 * 11.4.2 of IBTA Vol. 1).
475 		 *
476 		 * However, the way the SL is chosen below is consistent
477 		 * with the way that IB/qib works and is trying avoid
478 		 * introducing incompatibilities.
479 		 *
480 		 * See also OPA Vol. 1, section 9.7.6, and table 9-17.
481 		 */
482 		wc.sl = qp->remote_ah_attr.sl;
483 		/* zero fields that are N/A */
484 		wc.vendor_err = 0;
485 		wc.pkey_index = 0;
486 		wc.dlid_path_bits = 0;
487 		wc.port_num = 0;
488 		/* Signal completion event if the solicited bit is set. */
489 		rvt_cq_enter(ibcq_to_rvtcq(qp->ibqp.recv_cq), &wc,
490 			     (ohdr->bth[0] &
491 			      cpu_to_be32(IB_BTH_SOLICITED)) != 0);
492 		break;
493 
494 	case OP(RDMA_WRITE_FIRST):
495 	case OP(RDMA_WRITE_ONLY):
496 	case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE): /* consume RWQE */
497 rdma_first:
498 		if (unlikely(!(qp->qp_access_flags &
499 			       IB_ACCESS_REMOTE_WRITE))) {
500 			goto drop;
501 		}
502 		reth = &ohdr->u.rc.reth;
503 		qp->r_len = be32_to_cpu(reth->length);
504 		qp->r_rcv_len = 0;
505 		qp->r_sge.sg_list = NULL;
506 		if (qp->r_len != 0) {
507 			u32 rkey = be32_to_cpu(reth->rkey);
508 			u64 vaddr = be64_to_cpu(reth->vaddr);
509 			int ok;
510 
511 			/* Check rkey */
512 			ok = rvt_rkey_ok(qp, &qp->r_sge.sge, qp->r_len,
513 					 vaddr, rkey, IB_ACCESS_REMOTE_WRITE);
514 			if (unlikely(!ok))
515 				goto drop;
516 			qp->r_sge.num_sge = 1;
517 		} else {
518 			qp->r_sge.num_sge = 0;
519 			qp->r_sge.sge.mr = NULL;
520 			qp->r_sge.sge.vaddr = NULL;
521 			qp->r_sge.sge.length = 0;
522 			qp->r_sge.sge.sge_length = 0;
523 		}
524 		if (opcode == OP(RDMA_WRITE_ONLY)) {
525 			goto rdma_last;
526 		} else if (opcode == OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE)) {
527 			wc.ex.imm_data = ohdr->u.rc.imm_data;
528 			goto rdma_last_imm;
529 		}
530 		/* FALLTHROUGH */
531 	case OP(RDMA_WRITE_MIDDLE):
532 		/* Check for invalid length PMTU or posted rwqe len. */
533 		if (unlikely(tlen != (hdrsize + pmtu + 4)))
534 			goto drop;
535 		qp->r_rcv_len += pmtu;
536 		if (unlikely(qp->r_rcv_len > qp->r_len))
537 			goto drop;
538 		hfi1_copy_sge(&qp->r_sge, data, pmtu, 1, 0);
539 		break;
540 
541 	case OP(RDMA_WRITE_LAST_WITH_IMMEDIATE):
542 		wc.ex.imm_data = ohdr->u.imm_data;
543 rdma_last_imm:
544 		wc.wc_flags = IB_WC_WITH_IMM;
545 
546 		/* Get the number of bytes the message was padded by. */
547 		pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
548 		/* Check for invalid length. */
549 		/* LAST len should be >= 1 */
550 		if (unlikely(tlen < (hdrsize + pad + 4)))
551 			goto drop;
552 		/* Don't count the CRC. */
553 		tlen -= (hdrsize + pad + 4);
554 		if (unlikely(tlen + qp->r_rcv_len != qp->r_len))
555 			goto drop;
556 		if (test_and_clear_bit(RVT_R_REWIND_SGE, &qp->r_aflags)) {
557 			rvt_put_ss(&qp->s_rdma_read_sge);
558 		} else {
559 			ret = hfi1_rvt_get_rwqe(qp, 1);
560 			if (ret < 0)
561 				goto op_err;
562 			if (!ret)
563 				goto drop;
564 		}
565 		wc.byte_len = qp->r_len;
566 		wc.opcode = IB_WC_RECV_RDMA_WITH_IMM;
567 		hfi1_copy_sge(&qp->r_sge, data, tlen, 1, 0);
568 		rvt_put_ss(&qp->r_sge);
569 		goto last_imm;
570 
571 	case OP(RDMA_WRITE_LAST):
572 rdma_last:
573 		/* Get the number of bytes the message was padded by. */
574 		pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
575 		/* Check for invalid length. */
576 		/* LAST len should be >= 1 */
577 		if (unlikely(tlen < (hdrsize + pad + 4)))
578 			goto drop;
579 		/* Don't count the CRC. */
580 		tlen -= (hdrsize + pad + 4);
581 		if (unlikely(tlen + qp->r_rcv_len != qp->r_len))
582 			goto drop;
583 		hfi1_copy_sge(&qp->r_sge, data, tlen, 1, 0);
584 		rvt_put_ss(&qp->r_sge);
585 		break;
586 
587 	default:
588 		/* Drop packet for unknown opcodes. */
589 		goto drop;
590 	}
591 	qp->r_psn++;
592 	qp->r_state = opcode;
593 	return;
594 
595 rewind:
596 	set_bit(RVT_R_REWIND_SGE, &qp->r_aflags);
597 	qp->r_sge.num_sge = 0;
598 drop:
599 	ibp->rvp.n_pkt_drops++;
600 	return;
601 
602 op_err:
603 	hfi1_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
604 }
605