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1 /*
2  * GPL HEADER START
3  *
4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 only,
8  * as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope that it will be useful, but
11  * WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13  * General Public License version 2 for more details (a copy is included
14  * in the LICENSE file that accompanied this code).
15  *
16  * You should have received a copy of the GNU General Public License
17  * version 2 along with this program; If not, see
18  * http://www.gnu.org/licenses/gpl-2.0.html
19  *
20  * GPL HEADER END
21  */
22 /*
23  * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
24  * Use is subject to license terms.
25  *
26  * Copyright (c) 2011, 2015, Intel Corporation.
27  */
28 /*
29  * This file is part of Lustre, http://www.lustre.org/
30  * Lustre is a trademark of Sun Microsystems, Inc.
31  *
32  * lnet/lnet/lib-move.c
33  *
34  * Data movement routines
35  */
36 
37 #define DEBUG_SUBSYSTEM S_LNET
38 
39 #include "../../include/linux/lnet/lib-lnet.h"
40 #include <linux/nsproxy.h>
41 #include <net/net_namespace.h>
42 
43 static int local_nid_dist_zero = 1;
44 module_param(local_nid_dist_zero, int, 0444);
45 MODULE_PARM_DESC(local_nid_dist_zero, "Reserved");
46 
47 int
lnet_fail_nid(lnet_nid_t nid,unsigned int threshold)48 lnet_fail_nid(lnet_nid_t nid, unsigned int threshold)
49 {
50 	lnet_test_peer_t *tp;
51 	lnet_test_peer_t *temp;
52 	struct list_head *el;
53 	struct list_head *next;
54 	struct list_head cull;
55 
56 	/* NB: use lnet_net_lock(0) to serialize operations on test peers */
57 	if (threshold) {
58 		/* Adding a new entry */
59 		LIBCFS_ALLOC(tp, sizeof(*tp));
60 		if (!tp)
61 			return -ENOMEM;
62 
63 		tp->tp_nid = nid;
64 		tp->tp_threshold = threshold;
65 
66 		lnet_net_lock(0);
67 		list_add_tail(&tp->tp_list, &the_lnet.ln_test_peers);
68 		lnet_net_unlock(0);
69 		return 0;
70 	}
71 
72 	/* removing entries */
73 	INIT_LIST_HEAD(&cull);
74 
75 	lnet_net_lock(0);
76 
77 	list_for_each_safe(el, next, &the_lnet.ln_test_peers) {
78 		tp = list_entry(el, lnet_test_peer_t, tp_list);
79 
80 		if (!tp->tp_threshold ||    /* needs culling anyway */
81 		    nid == LNET_NID_ANY ||       /* removing all entries */
82 		    tp->tp_nid == nid) {	  /* matched this one */
83 			list_del(&tp->tp_list);
84 			list_add(&tp->tp_list, &cull);
85 		}
86 	}
87 
88 	lnet_net_unlock(0);
89 
90 	list_for_each_entry_safe(tp, temp, &cull, tp_list) {
91 		list_del(&tp->tp_list);
92 		LIBCFS_FREE(tp, sizeof(*tp));
93 	}
94 	return 0;
95 }
96 
97 static int
fail_peer(lnet_nid_t nid,int outgoing)98 fail_peer(lnet_nid_t nid, int outgoing)
99 {
100 	lnet_test_peer_t *tp;
101 	lnet_test_peer_t *temp;
102 	struct list_head *el;
103 	struct list_head *next;
104 	struct list_head cull;
105 	int fail = 0;
106 
107 	INIT_LIST_HEAD(&cull);
108 
109 	/* NB: use lnet_net_lock(0) to serialize operations on test peers */
110 	lnet_net_lock(0);
111 
112 	list_for_each_safe(el, next, &the_lnet.ln_test_peers) {
113 		tp = list_entry(el, lnet_test_peer_t, tp_list);
114 
115 		if (!tp->tp_threshold) {
116 			/* zombie entry */
117 			if (outgoing) {
118 				/*
119 				 * only cull zombies on outgoing tests,
120 				 * since we may be at interrupt priority on
121 				 * incoming messages.
122 				 */
123 				list_del(&tp->tp_list);
124 				list_add(&tp->tp_list, &cull);
125 			}
126 			continue;
127 		}
128 
129 		if (tp->tp_nid == LNET_NID_ANY || /* fail every peer */
130 		    nid == tp->tp_nid) {	/* fail this peer */
131 			fail = 1;
132 
133 			if (tp->tp_threshold != LNET_MD_THRESH_INF) {
134 				tp->tp_threshold--;
135 				if (outgoing &&
136 				    !tp->tp_threshold) {
137 					/* see above */
138 					list_del(&tp->tp_list);
139 					list_add(&tp->tp_list, &cull);
140 				}
141 			}
142 			break;
143 		}
144 	}
145 
146 	lnet_net_unlock(0);
147 
148 	list_for_each_entry_safe(tp, temp, &cull, tp_list) {
149 		list_del(&tp->tp_list);
150 
151 		LIBCFS_FREE(tp, sizeof(*tp));
152 	}
153 
154 	return fail;
155 }
156 
157 unsigned int
lnet_iov_nob(unsigned int niov,struct kvec * iov)158 lnet_iov_nob(unsigned int niov, struct kvec *iov)
159 {
160 	unsigned int nob = 0;
161 
162 	LASSERT(!niov || iov);
163 	while (niov-- > 0)
164 		nob += (iov++)->iov_len;
165 
166 	return nob;
167 }
168 EXPORT_SYMBOL(lnet_iov_nob);
169 
170 void
lnet_copy_iov2iter(struct iov_iter * to,unsigned int nsiov,const struct kvec * siov,unsigned int soffset,unsigned int nob)171 lnet_copy_iov2iter(struct iov_iter *to,
172 		   unsigned int nsiov, const struct kvec *siov,
173 		   unsigned int soffset, unsigned int nob)
174 {
175 	/* NB diov, siov are READ-ONLY */
176 	const char *s;
177 	size_t left;
178 
179 	if (!nob)
180 		return;
181 
182 	/* skip complete frags before 'soffset' */
183 	LASSERT(nsiov > 0);
184 	while (soffset >= siov->iov_len) {
185 		soffset -= siov->iov_len;
186 		siov++;
187 		nsiov--;
188 		LASSERT(nsiov > 0);
189 	}
190 
191 	s = (char *)siov->iov_base + soffset;
192 	left = siov->iov_len - soffset;
193 	do {
194 		size_t n, copy = left;
195 		LASSERT(nsiov > 0);
196 
197 		if (copy > nob)
198 			copy = nob;
199 		n = copy_to_iter(s, copy, to);
200 		if (n != copy)
201 			return;
202 		nob -= n;
203 
204 		siov++;
205 		s = (char *)siov->iov_base;
206 		left = siov->iov_len;
207 		nsiov--;
208 	} while (nob > 0);
209 }
210 EXPORT_SYMBOL(lnet_copy_iov2iter);
211 
212 void
lnet_copy_kiov2iter(struct iov_iter * to,unsigned int nsiov,const lnet_kiov_t * siov,unsigned int soffset,unsigned int nob)213 lnet_copy_kiov2iter(struct iov_iter *to,
214 		    unsigned int nsiov, const lnet_kiov_t *siov,
215 		    unsigned int soffset, unsigned int nob)
216 {
217 	if (!nob)
218 		return;
219 
220 	LASSERT(!in_interrupt());
221 
222 	LASSERT(nsiov > 0);
223 	while (soffset >= siov->bv_len) {
224 		soffset -= siov->bv_len;
225 		siov++;
226 		nsiov--;
227 		LASSERT(nsiov > 0);
228 	}
229 
230 	do {
231 		size_t copy = siov->bv_len - soffset, n;
232 
233 		LASSERT(nsiov > 0);
234 
235 		if (copy > nob)
236 			copy = nob;
237 		n = copy_page_to_iter(siov->bv_page,
238 				      siov->bv_offset + soffset,
239 				      copy, to);
240 		if (n != copy)
241 			return;
242 		nob -= n;
243 		siov++;
244 		nsiov--;
245 		soffset = 0;
246 	} while (nob > 0);
247 }
248 EXPORT_SYMBOL(lnet_copy_kiov2iter);
249 
250 int
lnet_extract_iov(int dst_niov,struct kvec * dst,int src_niov,const struct kvec * src,unsigned int offset,unsigned int len)251 lnet_extract_iov(int dst_niov, struct kvec *dst,
252 		 int src_niov, const struct kvec *src,
253 		 unsigned int offset, unsigned int len)
254 {
255 	/*
256 	 * Initialise 'dst' to the subset of 'src' starting at 'offset',
257 	 * for exactly 'len' bytes, and return the number of entries.
258 	 * NB not destructive to 'src'
259 	 */
260 	unsigned int frag_len;
261 	unsigned int niov;
262 
263 	if (!len)			   /* no data => */
264 		return 0;		     /* no frags */
265 
266 	LASSERT(src_niov > 0);
267 	while (offset >= src->iov_len) {      /* skip initial frags */
268 		offset -= src->iov_len;
269 		src_niov--;
270 		src++;
271 		LASSERT(src_niov > 0);
272 	}
273 
274 	niov = 1;
275 	for (;;) {
276 		LASSERT(src_niov > 0);
277 		LASSERT((int)niov <= dst_niov);
278 
279 		frag_len = src->iov_len - offset;
280 		dst->iov_base = ((char *)src->iov_base) + offset;
281 
282 		if (len <= frag_len) {
283 			dst->iov_len = len;
284 			return niov;
285 		}
286 
287 		dst->iov_len = frag_len;
288 
289 		len -= frag_len;
290 		dst++;
291 		src++;
292 		niov++;
293 		src_niov--;
294 		offset = 0;
295 	}
296 }
297 EXPORT_SYMBOL(lnet_extract_iov);
298 
299 unsigned int
lnet_kiov_nob(unsigned int niov,lnet_kiov_t * kiov)300 lnet_kiov_nob(unsigned int niov, lnet_kiov_t *kiov)
301 {
302 	unsigned int nob = 0;
303 
304 	LASSERT(!niov || kiov);
305 	while (niov-- > 0)
306 		nob += (kiov++)->bv_len;
307 
308 	return nob;
309 }
310 EXPORT_SYMBOL(lnet_kiov_nob);
311 
312 int
lnet_extract_kiov(int dst_niov,lnet_kiov_t * dst,int src_niov,const lnet_kiov_t * src,unsigned int offset,unsigned int len)313 lnet_extract_kiov(int dst_niov, lnet_kiov_t *dst,
314 		  int src_niov, const lnet_kiov_t *src,
315 		  unsigned int offset, unsigned int len)
316 {
317 	/*
318 	 * Initialise 'dst' to the subset of 'src' starting at 'offset',
319 	 * for exactly 'len' bytes, and return the number of entries.
320 	 * NB not destructive to 'src'
321 	 */
322 	unsigned int frag_len;
323 	unsigned int niov;
324 
325 	if (!len)			   /* no data => */
326 		return 0;		     /* no frags */
327 
328 	LASSERT(src_niov > 0);
329 	while (offset >= src->bv_len) {      /* skip initial frags */
330 		offset -= src->bv_len;
331 		src_niov--;
332 		src++;
333 		LASSERT(src_niov > 0);
334 	}
335 
336 	niov = 1;
337 	for (;;) {
338 		LASSERT(src_niov > 0);
339 		LASSERT((int)niov <= dst_niov);
340 
341 		frag_len = src->bv_len - offset;
342 		dst->bv_page = src->bv_page;
343 		dst->bv_offset = src->bv_offset + offset;
344 
345 		if (len <= frag_len) {
346 			dst->bv_len = len;
347 			LASSERT(dst->bv_offset + dst->bv_len
348 					<= PAGE_SIZE);
349 			return niov;
350 		}
351 
352 		dst->bv_len = frag_len;
353 		LASSERT(dst->bv_offset + dst->bv_len <= PAGE_SIZE);
354 
355 		len -= frag_len;
356 		dst++;
357 		src++;
358 		niov++;
359 		src_niov--;
360 		offset = 0;
361 	}
362 }
363 EXPORT_SYMBOL(lnet_extract_kiov);
364 
365 void
lnet_ni_recv(lnet_ni_t * ni,void * private,lnet_msg_t * msg,int delayed,unsigned int offset,unsigned int mlen,unsigned int rlen)366 lnet_ni_recv(lnet_ni_t *ni, void *private, lnet_msg_t *msg, int delayed,
367 	     unsigned int offset, unsigned int mlen, unsigned int rlen)
368 {
369 	unsigned int niov = 0;
370 	struct kvec *iov = NULL;
371 	lnet_kiov_t *kiov = NULL;
372 	struct iov_iter to;
373 	int rc;
374 
375 	LASSERT(!in_interrupt());
376 	LASSERT(!mlen || msg);
377 
378 	if (msg) {
379 		LASSERT(msg->msg_receiving);
380 		LASSERT(!msg->msg_sending);
381 		LASSERT(rlen == msg->msg_len);
382 		LASSERT(mlen <= msg->msg_len);
383 		LASSERT(msg->msg_offset == offset);
384 		LASSERT(msg->msg_wanted == mlen);
385 
386 		msg->msg_receiving = 0;
387 
388 		if (mlen) {
389 			niov = msg->msg_niov;
390 			iov  = msg->msg_iov;
391 			kiov = msg->msg_kiov;
392 
393 			LASSERT(niov > 0);
394 			LASSERT(!iov != !kiov);
395 		}
396 	}
397 
398 	if (iov) {
399 		iov_iter_kvec(&to, ITER_KVEC | READ, iov, niov, mlen + offset);
400 		iov_iter_advance(&to, offset);
401 	} else {
402 		iov_iter_bvec(&to, ITER_BVEC | READ, kiov, niov, mlen + offset);
403 		iov_iter_advance(&to, offset);
404 	}
405 	rc = ni->ni_lnd->lnd_recv(ni, private, msg, delayed, &to, rlen);
406 	if (rc < 0)
407 		lnet_finalize(ni, msg, rc);
408 }
409 
410 static void
lnet_setpayloadbuffer(lnet_msg_t * msg)411 lnet_setpayloadbuffer(lnet_msg_t *msg)
412 {
413 	lnet_libmd_t *md = msg->msg_md;
414 
415 	LASSERT(msg->msg_len > 0);
416 	LASSERT(!msg->msg_routing);
417 	LASSERT(md);
418 	LASSERT(!msg->msg_niov);
419 	LASSERT(!msg->msg_iov);
420 	LASSERT(!msg->msg_kiov);
421 
422 	msg->msg_niov = md->md_niov;
423 	if (md->md_options & LNET_MD_KIOV)
424 		msg->msg_kiov = md->md_iov.kiov;
425 	else
426 		msg->msg_iov = md->md_iov.iov;
427 }
428 
429 void
lnet_prep_send(lnet_msg_t * msg,int type,lnet_process_id_t target,unsigned int offset,unsigned int len)430 lnet_prep_send(lnet_msg_t *msg, int type, lnet_process_id_t target,
431 	       unsigned int offset, unsigned int len)
432 {
433 	msg->msg_type = type;
434 	msg->msg_target = target;
435 	msg->msg_len = len;
436 	msg->msg_offset = offset;
437 
438 	if (len)
439 		lnet_setpayloadbuffer(msg);
440 
441 	memset(&msg->msg_hdr, 0, sizeof(msg->msg_hdr));
442 	msg->msg_hdr.type	   = cpu_to_le32(type);
443 	msg->msg_hdr.dest_nid       = cpu_to_le64(target.nid);
444 	msg->msg_hdr.dest_pid       = cpu_to_le32(target.pid);
445 	/* src_nid will be set later */
446 	msg->msg_hdr.src_pid	= cpu_to_le32(the_lnet.ln_pid);
447 	msg->msg_hdr.payload_length = cpu_to_le32(len);
448 }
449 
450 static void
lnet_ni_send(lnet_ni_t * ni,lnet_msg_t * msg)451 lnet_ni_send(lnet_ni_t *ni, lnet_msg_t *msg)
452 {
453 	void *priv = msg->msg_private;
454 	int rc;
455 
456 	LASSERT(!in_interrupt());
457 	LASSERT(LNET_NETTYP(LNET_NIDNET(ni->ni_nid)) == LOLND ||
458 		(msg->msg_txcredit && msg->msg_peertxcredit));
459 
460 	rc = ni->ni_lnd->lnd_send(ni, priv, msg);
461 	if (rc < 0)
462 		lnet_finalize(ni, msg, rc);
463 }
464 
465 static int
lnet_ni_eager_recv(lnet_ni_t * ni,lnet_msg_t * msg)466 lnet_ni_eager_recv(lnet_ni_t *ni, lnet_msg_t *msg)
467 {
468 	int rc;
469 
470 	LASSERT(!msg->msg_sending);
471 	LASSERT(msg->msg_receiving);
472 	LASSERT(!msg->msg_rx_ready_delay);
473 	LASSERT(ni->ni_lnd->lnd_eager_recv);
474 
475 	msg->msg_rx_ready_delay = 1;
476 	rc = ni->ni_lnd->lnd_eager_recv(ni, msg->msg_private, msg,
477 					&msg->msg_private);
478 	if (rc) {
479 		CERROR("recv from %s / send to %s aborted: eager_recv failed %d\n",
480 		       libcfs_nid2str(msg->msg_rxpeer->lp_nid),
481 		       libcfs_id2str(msg->msg_target), rc);
482 		LASSERT(rc < 0); /* required by my callers */
483 	}
484 
485 	return rc;
486 }
487 
488 /* NB: caller shall hold a ref on 'lp' as I'd drop lnet_net_lock */
489 static void
lnet_ni_query_locked(lnet_ni_t * ni,lnet_peer_t * lp)490 lnet_ni_query_locked(lnet_ni_t *ni, lnet_peer_t *lp)
491 {
492 	unsigned long last_alive = 0;
493 
494 	LASSERT(lnet_peer_aliveness_enabled(lp));
495 	LASSERT(ni->ni_lnd->lnd_query);
496 
497 	lnet_net_unlock(lp->lp_cpt);
498 	ni->ni_lnd->lnd_query(ni, lp->lp_nid, &last_alive);
499 	lnet_net_lock(lp->lp_cpt);
500 
501 	lp->lp_last_query = cfs_time_current();
502 
503 	if (last_alive) /* NI has updated timestamp */
504 		lp->lp_last_alive = last_alive;
505 }
506 
507 /* NB: always called with lnet_net_lock held */
508 static inline int
lnet_peer_is_alive(lnet_peer_t * lp,unsigned long now)509 lnet_peer_is_alive(lnet_peer_t *lp, unsigned long now)
510 {
511 	int alive;
512 	unsigned long deadline;
513 
514 	LASSERT(lnet_peer_aliveness_enabled(lp));
515 
516 	/* Trust lnet_notify() if it has more recent aliveness news, but
517 	 * ignore the initial assumed death (see lnet_peers_start_down()).
518 	 */
519 	if (!lp->lp_alive && lp->lp_alive_count > 0 &&
520 	    cfs_time_aftereq(lp->lp_timestamp, lp->lp_last_alive))
521 		return 0;
522 
523 	deadline = cfs_time_add(lp->lp_last_alive,
524 				cfs_time_seconds(lp->lp_ni->ni_peertimeout));
525 	alive = cfs_time_after(deadline, now);
526 
527 	/* Update obsolete lp_alive except for routers assumed to be dead
528 	 * initially, because router checker would update aliveness in this
529 	 * case, and moreover lp_last_alive at peer creation is assumed.
530 	 */
531 	if (alive && !lp->lp_alive &&
532 	    !(lnet_isrouter(lp) && !lp->lp_alive_count))
533 		lnet_notify_locked(lp, 0, 1, lp->lp_last_alive);
534 
535 	return alive;
536 }
537 
538 /*
539  * NB: returns 1 when alive, 0 when dead, negative when error;
540  *     may drop the lnet_net_lock
541  */
542 static int
lnet_peer_alive_locked(lnet_peer_t * lp)543 lnet_peer_alive_locked(lnet_peer_t *lp)
544 {
545 	unsigned long now = cfs_time_current();
546 
547 	if (!lnet_peer_aliveness_enabled(lp))
548 		return -ENODEV;
549 
550 	if (lnet_peer_is_alive(lp, now))
551 		return 1;
552 
553 	/*
554 	 * Peer appears dead, but we should avoid frequent NI queries (at
555 	 * most once per lnet_queryinterval seconds).
556 	 */
557 	if (lp->lp_last_query) {
558 		static const int lnet_queryinterval = 1;
559 
560 		unsigned long next_query =
561 			   cfs_time_add(lp->lp_last_query,
562 					cfs_time_seconds(lnet_queryinterval));
563 
564 		if (time_before(now, next_query)) {
565 			if (lp->lp_alive)
566 				CWARN("Unexpected aliveness of peer %s: %d < %d (%d/%d)\n",
567 				      libcfs_nid2str(lp->lp_nid),
568 				      (int)now, (int)next_query,
569 				      lnet_queryinterval,
570 				      lp->lp_ni->ni_peertimeout);
571 			return 0;
572 		}
573 	}
574 
575 	/* query NI for latest aliveness news */
576 	lnet_ni_query_locked(lp->lp_ni, lp);
577 
578 	if (lnet_peer_is_alive(lp, now))
579 		return 1;
580 
581 	lnet_notify_locked(lp, 0, 0, lp->lp_last_alive);
582 	return 0;
583 }
584 
585 /**
586  * \param msg The message to be sent.
587  * \param do_send True if lnet_ni_send() should be called in this function.
588  *	  lnet_send() is going to lnet_net_unlock immediately after this, so
589  *	  it sets do_send FALSE and I don't do the unlock/send/lock bit.
590  *
591  * \retval LNET_CREDIT_OK If \a msg sent or OK to send.
592  * \retval LNET_CREDIT_WAIT If \a msg blocked for credit.
593  * \retval -EHOSTUNREACH If the next hop of the message appears dead.
594  * \retval -ECANCELED If the MD of the message has been unlinked.
595  */
596 static int
lnet_post_send_locked(lnet_msg_t * msg,int do_send)597 lnet_post_send_locked(lnet_msg_t *msg, int do_send)
598 {
599 	lnet_peer_t *lp = msg->msg_txpeer;
600 	lnet_ni_t *ni = lp->lp_ni;
601 	int cpt = msg->msg_tx_cpt;
602 	struct lnet_tx_queue *tq = ni->ni_tx_queues[cpt];
603 
604 	/* non-lnet_send() callers have checked before */
605 	LASSERT(!do_send || msg->msg_tx_delayed);
606 	LASSERT(!msg->msg_receiving);
607 	LASSERT(msg->msg_tx_committed);
608 
609 	/* NB 'lp' is always the next hop */
610 	if (!(msg->msg_target.pid & LNET_PID_USERFLAG) &&
611 	    !lnet_peer_alive_locked(lp)) {
612 		the_lnet.ln_counters[cpt]->drop_count++;
613 		the_lnet.ln_counters[cpt]->drop_length += msg->msg_len;
614 		lnet_net_unlock(cpt);
615 
616 		CNETERR("Dropping message for %s: peer not alive\n",
617 			libcfs_id2str(msg->msg_target));
618 		if (do_send)
619 			lnet_finalize(ni, msg, -EHOSTUNREACH);
620 
621 		lnet_net_lock(cpt);
622 		return -EHOSTUNREACH;
623 	}
624 
625 	if (msg->msg_md &&
626 	    (msg->msg_md->md_flags & LNET_MD_FLAG_ABORTED)) {
627 		lnet_net_unlock(cpt);
628 
629 		CNETERR("Aborting message for %s: LNetM[DE]Unlink() already called on the MD/ME.\n",
630 			libcfs_id2str(msg->msg_target));
631 		if (do_send)
632 			lnet_finalize(ni, msg, -ECANCELED);
633 
634 		lnet_net_lock(cpt);
635 		return -ECANCELED;
636 	}
637 
638 	if (!msg->msg_peertxcredit) {
639 		LASSERT((lp->lp_txcredits < 0) ==
640 			!list_empty(&lp->lp_txq));
641 
642 		msg->msg_peertxcredit = 1;
643 		lp->lp_txqnob += msg->msg_len + sizeof(lnet_hdr_t);
644 		lp->lp_txcredits--;
645 
646 		if (lp->lp_txcredits < lp->lp_mintxcredits)
647 			lp->lp_mintxcredits = lp->lp_txcredits;
648 
649 		if (lp->lp_txcredits < 0) {
650 			msg->msg_tx_delayed = 1;
651 			list_add_tail(&msg->msg_list, &lp->lp_txq);
652 			return LNET_CREDIT_WAIT;
653 		}
654 	}
655 
656 	if (!msg->msg_txcredit) {
657 		LASSERT((tq->tq_credits < 0) ==
658 			!list_empty(&tq->tq_delayed));
659 
660 		msg->msg_txcredit = 1;
661 		tq->tq_credits--;
662 
663 		if (tq->tq_credits < tq->tq_credits_min)
664 			tq->tq_credits_min = tq->tq_credits;
665 
666 		if (tq->tq_credits < 0) {
667 			msg->msg_tx_delayed = 1;
668 			list_add_tail(&msg->msg_list, &tq->tq_delayed);
669 			return LNET_CREDIT_WAIT;
670 		}
671 	}
672 
673 	if (do_send) {
674 		lnet_net_unlock(cpt);
675 		lnet_ni_send(ni, msg);
676 		lnet_net_lock(cpt);
677 	}
678 	return LNET_CREDIT_OK;
679 }
680 
681 static lnet_rtrbufpool_t *
lnet_msg2bufpool(lnet_msg_t * msg)682 lnet_msg2bufpool(lnet_msg_t *msg)
683 {
684 	lnet_rtrbufpool_t *rbp;
685 	int cpt;
686 
687 	LASSERT(msg->msg_rx_committed);
688 
689 	cpt = msg->msg_rx_cpt;
690 	rbp = &the_lnet.ln_rtrpools[cpt][0];
691 
692 	LASSERT(msg->msg_len <= LNET_MTU);
693 	while (msg->msg_len > (unsigned int)rbp->rbp_npages * PAGE_SIZE) {
694 		rbp++;
695 		LASSERT(rbp < &the_lnet.ln_rtrpools[cpt][LNET_NRBPOOLS]);
696 	}
697 
698 	return rbp;
699 }
700 
701 static int
lnet_post_routed_recv_locked(lnet_msg_t * msg,int do_recv)702 lnet_post_routed_recv_locked(lnet_msg_t *msg, int do_recv)
703 {
704 	/*
705 	 * lnet_parse is going to lnet_net_unlock immediately after this, so it
706 	 * sets do_recv FALSE and I don't do the unlock/send/lock bit.
707 	 * I return LNET_CREDIT_WAIT if msg blocked and LNET_CREDIT_OK if
708 	 * received or OK to receive
709 	 */
710 	lnet_peer_t *lp = msg->msg_rxpeer;
711 	lnet_rtrbufpool_t *rbp;
712 	lnet_rtrbuf_t *rb;
713 
714 	LASSERT(!msg->msg_iov);
715 	LASSERT(!msg->msg_kiov);
716 	LASSERT(!msg->msg_niov);
717 	LASSERT(msg->msg_routing);
718 	LASSERT(msg->msg_receiving);
719 	LASSERT(!msg->msg_sending);
720 
721 	/* non-lnet_parse callers only receive delayed messages */
722 	LASSERT(!do_recv || msg->msg_rx_delayed);
723 
724 	if (!msg->msg_peerrtrcredit) {
725 		LASSERT((lp->lp_rtrcredits < 0) ==
726 			!list_empty(&lp->lp_rtrq));
727 
728 		msg->msg_peerrtrcredit = 1;
729 		lp->lp_rtrcredits--;
730 		if (lp->lp_rtrcredits < lp->lp_minrtrcredits)
731 			lp->lp_minrtrcredits = lp->lp_rtrcredits;
732 
733 		if (lp->lp_rtrcredits < 0) {
734 			/* must have checked eager_recv before here */
735 			LASSERT(msg->msg_rx_ready_delay);
736 			msg->msg_rx_delayed = 1;
737 			list_add_tail(&msg->msg_list, &lp->lp_rtrq);
738 			return LNET_CREDIT_WAIT;
739 		}
740 	}
741 
742 	rbp = lnet_msg2bufpool(msg);
743 
744 	if (!msg->msg_rtrcredit) {
745 		msg->msg_rtrcredit = 1;
746 		rbp->rbp_credits--;
747 		if (rbp->rbp_credits < rbp->rbp_mincredits)
748 			rbp->rbp_mincredits = rbp->rbp_credits;
749 
750 		if (rbp->rbp_credits < 0) {
751 			/* must have checked eager_recv before here */
752 			LASSERT(msg->msg_rx_ready_delay);
753 			msg->msg_rx_delayed = 1;
754 			list_add_tail(&msg->msg_list, &rbp->rbp_msgs);
755 			return LNET_CREDIT_WAIT;
756 		}
757 	}
758 
759 	LASSERT(!list_empty(&rbp->rbp_bufs));
760 	rb = list_entry(rbp->rbp_bufs.next, lnet_rtrbuf_t, rb_list);
761 	list_del(&rb->rb_list);
762 
763 	msg->msg_niov = rbp->rbp_npages;
764 	msg->msg_kiov = &rb->rb_kiov[0];
765 
766 	if (do_recv) {
767 		int cpt = msg->msg_rx_cpt;
768 
769 		lnet_net_unlock(cpt);
770 		lnet_ni_recv(lp->lp_ni, msg->msg_private, msg, 1,
771 			     0, msg->msg_len, msg->msg_len);
772 		lnet_net_lock(cpt);
773 	}
774 	return LNET_CREDIT_OK;
775 }
776 
777 void
lnet_return_tx_credits_locked(lnet_msg_t * msg)778 lnet_return_tx_credits_locked(lnet_msg_t *msg)
779 {
780 	lnet_peer_t *txpeer = msg->msg_txpeer;
781 	lnet_msg_t *msg2;
782 
783 	if (msg->msg_txcredit) {
784 		struct lnet_ni *ni = txpeer->lp_ni;
785 		struct lnet_tx_queue *tq = ni->ni_tx_queues[msg->msg_tx_cpt];
786 
787 		/* give back NI txcredits */
788 		msg->msg_txcredit = 0;
789 
790 		LASSERT((tq->tq_credits < 0) ==
791 			!list_empty(&tq->tq_delayed));
792 
793 		tq->tq_credits++;
794 		if (tq->tq_credits <= 0) {
795 			msg2 = list_entry(tq->tq_delayed.next,
796 					  lnet_msg_t, msg_list);
797 			list_del(&msg2->msg_list);
798 
799 			LASSERT(msg2->msg_txpeer->lp_ni == ni);
800 			LASSERT(msg2->msg_tx_delayed);
801 
802 			(void)lnet_post_send_locked(msg2, 1);
803 		}
804 	}
805 
806 	if (msg->msg_peertxcredit) {
807 		/* give back peer txcredits */
808 		msg->msg_peertxcredit = 0;
809 
810 		LASSERT((txpeer->lp_txcredits < 0) ==
811 			!list_empty(&txpeer->lp_txq));
812 
813 		txpeer->lp_txqnob -= msg->msg_len + sizeof(lnet_hdr_t);
814 		LASSERT(txpeer->lp_txqnob >= 0);
815 
816 		txpeer->lp_txcredits++;
817 		if (txpeer->lp_txcredits <= 0) {
818 			msg2 = list_entry(txpeer->lp_txq.next,
819 					  lnet_msg_t, msg_list);
820 			list_del(&msg2->msg_list);
821 
822 			LASSERT(msg2->msg_txpeer == txpeer);
823 			LASSERT(msg2->msg_tx_delayed);
824 
825 			(void)lnet_post_send_locked(msg2, 1);
826 		}
827 	}
828 
829 	if (txpeer) {
830 		msg->msg_txpeer = NULL;
831 		lnet_peer_decref_locked(txpeer);
832 	}
833 }
834 
835 void
lnet_schedule_blocked_locked(lnet_rtrbufpool_t * rbp)836 lnet_schedule_blocked_locked(lnet_rtrbufpool_t *rbp)
837 {
838 	lnet_msg_t *msg;
839 
840 	if (list_empty(&rbp->rbp_msgs))
841 		return;
842 	msg = list_entry(rbp->rbp_msgs.next,
843 			 lnet_msg_t, msg_list);
844 	list_del(&msg->msg_list);
845 
846 	(void)lnet_post_routed_recv_locked(msg, 1);
847 }
848 
849 void
lnet_drop_routed_msgs_locked(struct list_head * list,int cpt)850 lnet_drop_routed_msgs_locked(struct list_head *list, int cpt)
851 {
852 	struct list_head drop;
853 	lnet_msg_t *msg;
854 	lnet_msg_t *tmp;
855 
856 	INIT_LIST_HEAD(&drop);
857 
858 	list_splice_init(list, &drop);
859 
860 	lnet_net_unlock(cpt);
861 
862 	list_for_each_entry_safe(msg, tmp, &drop, msg_list) {
863 		lnet_ni_recv(msg->msg_rxpeer->lp_ni, msg->msg_private, NULL,
864 			     0, 0, 0, msg->msg_hdr.payload_length);
865 		list_del_init(&msg->msg_list);
866 		lnet_finalize(NULL, msg, -ECANCELED);
867 	}
868 
869 	lnet_net_lock(cpt);
870 }
871 
872 void
lnet_return_rx_credits_locked(lnet_msg_t * msg)873 lnet_return_rx_credits_locked(lnet_msg_t *msg)
874 {
875 	lnet_peer_t *rxpeer = msg->msg_rxpeer;
876 	lnet_msg_t *msg2;
877 
878 	if (msg->msg_rtrcredit) {
879 		/* give back global router credits */
880 		lnet_rtrbuf_t *rb;
881 		lnet_rtrbufpool_t *rbp;
882 
883 		/*
884 		 * NB If a msg ever blocks for a buffer in rbp_msgs, it stays
885 		 * there until it gets one allocated, or aborts the wait
886 		 * itself
887 		 */
888 		LASSERT(msg->msg_kiov);
889 
890 		rb = list_entry(msg->msg_kiov, lnet_rtrbuf_t, rb_kiov[0]);
891 		rbp = rb->rb_pool;
892 
893 		msg->msg_kiov = NULL;
894 		msg->msg_rtrcredit = 0;
895 
896 		LASSERT(rbp == lnet_msg2bufpool(msg));
897 
898 		LASSERT((rbp->rbp_credits > 0) ==
899 			!list_empty(&rbp->rbp_bufs));
900 
901 		/*
902 		 * If routing is now turned off, we just drop this buffer and
903 		 * don't bother trying to return credits.
904 		 */
905 		if (!the_lnet.ln_routing) {
906 			lnet_destroy_rtrbuf(rb, rbp->rbp_npages);
907 			goto routing_off;
908 		}
909 
910 		/*
911 		 * It is possible that a user has lowered the desired number of
912 		 * buffers in this pool.  Make sure we never put back
913 		 * more buffers than the stated number.
914 		 */
915 		if (unlikely(rbp->rbp_credits >= rbp->rbp_req_nbuffers)) {
916 			/* Discard this buffer so we don't have too many. */
917 			lnet_destroy_rtrbuf(rb, rbp->rbp_npages);
918 			rbp->rbp_nbuffers--;
919 		} else {
920 			list_add(&rb->rb_list, &rbp->rbp_bufs);
921 			rbp->rbp_credits++;
922 			if (rbp->rbp_credits <= 0)
923 				lnet_schedule_blocked_locked(rbp);
924 		}
925 	}
926 
927 routing_off:
928 	if (msg->msg_peerrtrcredit) {
929 		/* give back peer router credits */
930 		msg->msg_peerrtrcredit = 0;
931 
932 		LASSERT((rxpeer->lp_rtrcredits < 0) ==
933 			!list_empty(&rxpeer->lp_rtrq));
934 
935 		rxpeer->lp_rtrcredits++;
936 		/*
937 		 * drop all messages which are queued to be routed on that
938 		 * peer.
939 		 */
940 		if (!the_lnet.ln_routing) {
941 			lnet_drop_routed_msgs_locked(&rxpeer->lp_rtrq,
942 						     msg->msg_rx_cpt);
943 		} else if (rxpeer->lp_rtrcredits <= 0) {
944 			msg2 = list_entry(rxpeer->lp_rtrq.next,
945 					  lnet_msg_t, msg_list);
946 			list_del(&msg2->msg_list);
947 
948 			(void)lnet_post_routed_recv_locked(msg2, 1);
949 		}
950 	}
951 	if (rxpeer) {
952 		msg->msg_rxpeer = NULL;
953 		lnet_peer_decref_locked(rxpeer);
954 	}
955 }
956 
957 static int
lnet_compare_routes(lnet_route_t * r1,lnet_route_t * r2)958 lnet_compare_routes(lnet_route_t *r1, lnet_route_t *r2)
959 {
960 	lnet_peer_t *p1 = r1->lr_gateway;
961 	lnet_peer_t *p2 = r2->lr_gateway;
962 	int r1_hops = (r1->lr_hops == LNET_UNDEFINED_HOPS) ? 1 : r1->lr_hops;
963 	int r2_hops = (r2->lr_hops == LNET_UNDEFINED_HOPS) ? 1 : r2->lr_hops;
964 
965 	if (r1->lr_priority < r2->lr_priority)
966 		return 1;
967 
968 	if (r1->lr_priority > r2->lr_priority)
969 		return -ERANGE;
970 
971 	if (r1_hops < r2_hops)
972 		return 1;
973 
974 	if (r1_hops > r2_hops)
975 		return -ERANGE;
976 
977 	if (p1->lp_txqnob < p2->lp_txqnob)
978 		return 1;
979 
980 	if (p1->lp_txqnob > p2->lp_txqnob)
981 		return -ERANGE;
982 
983 	if (p1->lp_txcredits > p2->lp_txcredits)
984 		return 1;
985 
986 	if (p1->lp_txcredits < p2->lp_txcredits)
987 		return -ERANGE;
988 
989 	if (r1->lr_seq - r2->lr_seq <= 0)
990 		return 1;
991 
992 	return -ERANGE;
993 }
994 
995 static lnet_peer_t *
lnet_find_route_locked(lnet_ni_t * ni,lnet_nid_t target,lnet_nid_t rtr_nid)996 lnet_find_route_locked(lnet_ni_t *ni, lnet_nid_t target, lnet_nid_t rtr_nid)
997 {
998 	lnet_remotenet_t *rnet;
999 	lnet_route_t *route;
1000 	lnet_route_t *best_route;
1001 	lnet_route_t *last_route;
1002 	struct lnet_peer *lp_best;
1003 	struct lnet_peer *lp;
1004 	int rc;
1005 
1006 	/*
1007 	 * If @rtr_nid is not LNET_NID_ANY, return the gateway with
1008 	 * rtr_nid nid, otherwise find the best gateway I can use
1009 	 */
1010 	rnet = lnet_find_net_locked(LNET_NIDNET(target));
1011 	if (!rnet)
1012 		return NULL;
1013 
1014 	lp_best = NULL;
1015 	best_route = NULL;
1016 	last_route = NULL;
1017 	list_for_each_entry(route, &rnet->lrn_routes, lr_list) {
1018 		lp = route->lr_gateway;
1019 
1020 		if (!lnet_is_route_alive(route))
1021 			continue;
1022 
1023 		if (ni && lp->lp_ni != ni)
1024 			continue;
1025 
1026 		if (lp->lp_nid == rtr_nid) /* it's pre-determined router */
1027 			return lp;
1028 
1029 		if (!lp_best) {
1030 			best_route = route;
1031 			last_route = route;
1032 			lp_best = lp;
1033 			continue;
1034 		}
1035 
1036 		/* no protection on below fields, but it's harmless */
1037 		if (last_route->lr_seq - route->lr_seq < 0)
1038 			last_route = route;
1039 
1040 		rc = lnet_compare_routes(route, best_route);
1041 		if (rc < 0)
1042 			continue;
1043 
1044 		best_route = route;
1045 		lp_best = lp;
1046 	}
1047 
1048 	/*
1049 	 * set sequence number on the best router to the latest sequence + 1
1050 	 * so we can round-robin all routers, it's race and inaccurate but
1051 	 * harmless and functional
1052 	 */
1053 	if (best_route)
1054 		best_route->lr_seq = last_route->lr_seq + 1;
1055 	return lp_best;
1056 }
1057 
1058 int
lnet_send(lnet_nid_t src_nid,lnet_msg_t * msg,lnet_nid_t rtr_nid)1059 lnet_send(lnet_nid_t src_nid, lnet_msg_t *msg, lnet_nid_t rtr_nid)
1060 {
1061 	lnet_nid_t dst_nid = msg->msg_target.nid;
1062 	struct lnet_ni *src_ni;
1063 	struct lnet_ni *local_ni;
1064 	struct lnet_peer *lp;
1065 	int cpt;
1066 	int cpt2;
1067 	int rc;
1068 
1069 	/*
1070 	 * NB: rtr_nid is set to LNET_NID_ANY for all current use-cases,
1071 	 * but we might want to use pre-determined router for ACK/REPLY
1072 	 * in the future
1073 	 */
1074 	/* NB: ni == interface pre-determined (ACK/REPLY) */
1075 	LASSERT(!msg->msg_txpeer);
1076 	LASSERT(!msg->msg_sending);
1077 	LASSERT(!msg->msg_target_is_router);
1078 	LASSERT(!msg->msg_receiving);
1079 
1080 	msg->msg_sending = 1;
1081 
1082 	LASSERT(!msg->msg_tx_committed);
1083 	cpt = lnet_cpt_of_nid(rtr_nid == LNET_NID_ANY ? dst_nid : rtr_nid);
1084  again:
1085 	lnet_net_lock(cpt);
1086 
1087 	if (the_lnet.ln_shutdown) {
1088 		lnet_net_unlock(cpt);
1089 		return -ESHUTDOWN;
1090 	}
1091 
1092 	if (src_nid == LNET_NID_ANY) {
1093 		src_ni = NULL;
1094 	} else {
1095 		src_ni = lnet_nid2ni_locked(src_nid, cpt);
1096 		if (!src_ni) {
1097 			lnet_net_unlock(cpt);
1098 			LCONSOLE_WARN("Can't send to %s: src %s is not a local nid\n",
1099 				      libcfs_nid2str(dst_nid),
1100 				      libcfs_nid2str(src_nid));
1101 			return -EINVAL;
1102 		}
1103 		LASSERT(!msg->msg_routing);
1104 	}
1105 
1106 	/* Is this for someone on a local network? */
1107 	local_ni = lnet_net2ni_locked(LNET_NIDNET(dst_nid), cpt);
1108 
1109 	if (local_ni) {
1110 		if (!src_ni) {
1111 			src_ni = local_ni;
1112 			src_nid = src_ni->ni_nid;
1113 		} else if (src_ni == local_ni) {
1114 			lnet_ni_decref_locked(local_ni, cpt);
1115 		} else {
1116 			lnet_ni_decref_locked(local_ni, cpt);
1117 			lnet_ni_decref_locked(src_ni, cpt);
1118 			lnet_net_unlock(cpt);
1119 			LCONSOLE_WARN("No route to %s via from %s\n",
1120 				      libcfs_nid2str(dst_nid),
1121 				      libcfs_nid2str(src_nid));
1122 			return -EINVAL;
1123 		}
1124 
1125 		LASSERT(src_nid != LNET_NID_ANY);
1126 		lnet_msg_commit(msg, cpt);
1127 
1128 		if (!msg->msg_routing)
1129 			msg->msg_hdr.src_nid = cpu_to_le64(src_nid);
1130 
1131 		if (src_ni == the_lnet.ln_loni) {
1132 			/* No send credit hassles with LOLND */
1133 			lnet_net_unlock(cpt);
1134 			lnet_ni_send(src_ni, msg);
1135 
1136 			lnet_net_lock(cpt);
1137 			lnet_ni_decref_locked(src_ni, cpt);
1138 			lnet_net_unlock(cpt);
1139 			return 0;
1140 		}
1141 
1142 		rc = lnet_nid2peer_locked(&lp, dst_nid, cpt);
1143 		/* lp has ref on src_ni; lose mine */
1144 		lnet_ni_decref_locked(src_ni, cpt);
1145 		if (rc) {
1146 			lnet_net_unlock(cpt);
1147 			LCONSOLE_WARN("Error %d finding peer %s\n", rc,
1148 				      libcfs_nid2str(dst_nid));
1149 			/* ENOMEM or shutting down */
1150 			return rc;
1151 		}
1152 		LASSERT(lp->lp_ni == src_ni);
1153 	} else {
1154 		/* sending to a remote network */
1155 		lp = lnet_find_route_locked(src_ni, dst_nid, rtr_nid);
1156 		if (!lp) {
1157 			if (src_ni)
1158 				lnet_ni_decref_locked(src_ni, cpt);
1159 			lnet_net_unlock(cpt);
1160 
1161 			LCONSOLE_WARN("No route to %s via %s (all routers down)\n",
1162 				      libcfs_id2str(msg->msg_target),
1163 				      libcfs_nid2str(src_nid));
1164 			return -EHOSTUNREACH;
1165 		}
1166 
1167 		/*
1168 		 * rtr_nid is LNET_NID_ANY or NID of pre-determined router,
1169 		 * it's possible that rtr_nid isn't LNET_NID_ANY and lp isn't
1170 		 * pre-determined router, this can happen if router table
1171 		 * was changed when we release the lock
1172 		 */
1173 		if (rtr_nid != lp->lp_nid) {
1174 			cpt2 = lnet_cpt_of_nid_locked(lp->lp_nid);
1175 			if (cpt2 != cpt) {
1176 				if (src_ni)
1177 					lnet_ni_decref_locked(src_ni, cpt);
1178 				lnet_net_unlock(cpt);
1179 
1180 				rtr_nid = lp->lp_nid;
1181 				cpt = cpt2;
1182 				goto again;
1183 			}
1184 		}
1185 
1186 		CDEBUG(D_NET, "Best route to %s via %s for %s %d\n",
1187 		       libcfs_nid2str(dst_nid), libcfs_nid2str(lp->lp_nid),
1188 		       lnet_msgtyp2str(msg->msg_type), msg->msg_len);
1189 
1190 		if (!src_ni) {
1191 			src_ni = lp->lp_ni;
1192 			src_nid = src_ni->ni_nid;
1193 		} else {
1194 			LASSERT(src_ni == lp->lp_ni);
1195 			lnet_ni_decref_locked(src_ni, cpt);
1196 		}
1197 
1198 		lnet_peer_addref_locked(lp);
1199 
1200 		LASSERT(src_nid != LNET_NID_ANY);
1201 		lnet_msg_commit(msg, cpt);
1202 
1203 		if (!msg->msg_routing) {
1204 			/* I'm the source and now I know which NI to send on */
1205 			msg->msg_hdr.src_nid = cpu_to_le64(src_nid);
1206 		}
1207 
1208 		msg->msg_target_is_router = 1;
1209 		msg->msg_target.nid = lp->lp_nid;
1210 		msg->msg_target.pid = LNET_PID_LUSTRE;
1211 	}
1212 
1213 	/* 'lp' is our best choice of peer */
1214 
1215 	LASSERT(!msg->msg_peertxcredit);
1216 	LASSERT(!msg->msg_txcredit);
1217 	LASSERT(!msg->msg_txpeer);
1218 
1219 	msg->msg_txpeer = lp;		   /* msg takes my ref on lp */
1220 
1221 	rc = lnet_post_send_locked(msg, 0);
1222 	lnet_net_unlock(cpt);
1223 
1224 	if (rc < 0)
1225 		return rc;
1226 
1227 	if (rc == LNET_CREDIT_OK)
1228 		lnet_ni_send(src_ni, msg);
1229 
1230 	return 0; /* rc == LNET_CREDIT_OK or LNET_CREDIT_WAIT */
1231 }
1232 
1233 void
lnet_drop_message(lnet_ni_t * ni,int cpt,void * private,unsigned int nob)1234 lnet_drop_message(lnet_ni_t *ni, int cpt, void *private, unsigned int nob)
1235 {
1236 	lnet_net_lock(cpt);
1237 	the_lnet.ln_counters[cpt]->drop_count++;
1238 	the_lnet.ln_counters[cpt]->drop_length += nob;
1239 	lnet_net_unlock(cpt);
1240 
1241 	lnet_ni_recv(ni, private, NULL, 0, 0, 0, nob);
1242 }
1243 
1244 static void
lnet_recv_put(lnet_ni_t * ni,lnet_msg_t * msg)1245 lnet_recv_put(lnet_ni_t *ni, lnet_msg_t *msg)
1246 {
1247 	lnet_hdr_t *hdr = &msg->msg_hdr;
1248 
1249 	if (msg->msg_wanted)
1250 		lnet_setpayloadbuffer(msg);
1251 
1252 	lnet_build_msg_event(msg, LNET_EVENT_PUT);
1253 
1254 	/*
1255 	 * Must I ACK?  If so I'll grab the ack_wmd out of the header and put
1256 	 * it back into the ACK during lnet_finalize()
1257 	 */
1258 	msg->msg_ack = !lnet_is_wire_handle_none(&hdr->msg.put.ack_wmd) &&
1259 		       !(msg->msg_md->md_options & LNET_MD_ACK_DISABLE);
1260 
1261 	lnet_ni_recv(ni, msg->msg_private, msg, msg->msg_rx_delayed,
1262 		     msg->msg_offset, msg->msg_wanted, hdr->payload_length);
1263 }
1264 
1265 static int
lnet_parse_put(lnet_ni_t * ni,lnet_msg_t * msg)1266 lnet_parse_put(lnet_ni_t *ni, lnet_msg_t *msg)
1267 {
1268 	lnet_hdr_t *hdr = &msg->msg_hdr;
1269 	struct lnet_match_info info;
1270 	bool ready_delay;
1271 	int rc;
1272 
1273 	/* Convert put fields to host byte order */
1274 	hdr->msg.put.match_bits	= le64_to_cpu(hdr->msg.put.match_bits);
1275 	hdr->msg.put.ptl_index	= le32_to_cpu(hdr->msg.put.ptl_index);
1276 	hdr->msg.put.offset	= le32_to_cpu(hdr->msg.put.offset);
1277 
1278 	info.mi_id.nid	= hdr->src_nid;
1279 	info.mi_id.pid	= hdr->src_pid;
1280 	info.mi_opc	= LNET_MD_OP_PUT;
1281 	info.mi_portal	= hdr->msg.put.ptl_index;
1282 	info.mi_rlength	= hdr->payload_length;
1283 	info.mi_roffset	= hdr->msg.put.offset;
1284 	info.mi_mbits	= hdr->msg.put.match_bits;
1285 
1286 	msg->msg_rx_ready_delay = !ni->ni_lnd->lnd_eager_recv;
1287 	ready_delay = msg->msg_rx_ready_delay;
1288 
1289  again:
1290 	rc = lnet_ptl_match_md(&info, msg);
1291 	switch (rc) {
1292 	default:
1293 		LBUG();
1294 
1295 	case LNET_MATCHMD_OK:
1296 		lnet_recv_put(ni, msg);
1297 		return 0;
1298 
1299 	case LNET_MATCHMD_NONE:
1300 		/**
1301 		 * no eager_recv or has already called it, should
1302 		 * have been attached on delayed list
1303 		 */
1304 		if (ready_delay)
1305 			return 0;
1306 
1307 		rc = lnet_ni_eager_recv(ni, msg);
1308 		if (!rc) {
1309 			ready_delay = true;
1310 			goto again;
1311 		}
1312 		/* fall through */
1313 
1314 	case LNET_MATCHMD_DROP:
1315 		CNETERR("Dropping PUT from %s portal %d match %llu offset %d length %d: %d\n",
1316 			libcfs_id2str(info.mi_id), info.mi_portal,
1317 			info.mi_mbits, info.mi_roffset, info.mi_rlength, rc);
1318 
1319 		return -ENOENT;	/* -ve: OK but no match */
1320 	}
1321 }
1322 
1323 static int
lnet_parse_get(lnet_ni_t * ni,lnet_msg_t * msg,int rdma_get)1324 lnet_parse_get(lnet_ni_t *ni, lnet_msg_t *msg, int rdma_get)
1325 {
1326 	struct lnet_match_info info;
1327 	lnet_hdr_t *hdr = &msg->msg_hdr;
1328 	lnet_handle_wire_t reply_wmd;
1329 	int rc;
1330 
1331 	/* Convert get fields to host byte order */
1332 	hdr->msg.get.match_bits  = le64_to_cpu(hdr->msg.get.match_bits);
1333 	hdr->msg.get.ptl_index   = le32_to_cpu(hdr->msg.get.ptl_index);
1334 	hdr->msg.get.sink_length = le32_to_cpu(hdr->msg.get.sink_length);
1335 	hdr->msg.get.src_offset  = le32_to_cpu(hdr->msg.get.src_offset);
1336 
1337 	info.mi_id.nid  = hdr->src_nid;
1338 	info.mi_id.pid  = hdr->src_pid;
1339 	info.mi_opc     = LNET_MD_OP_GET;
1340 	info.mi_portal  = hdr->msg.get.ptl_index;
1341 	info.mi_rlength = hdr->msg.get.sink_length;
1342 	info.mi_roffset = hdr->msg.get.src_offset;
1343 	info.mi_mbits   = hdr->msg.get.match_bits;
1344 
1345 	rc = lnet_ptl_match_md(&info, msg);
1346 	if (rc == LNET_MATCHMD_DROP) {
1347 		CNETERR("Dropping GET from %s portal %d match %llu offset %d length %d\n",
1348 			libcfs_id2str(info.mi_id), info.mi_portal,
1349 			info.mi_mbits, info.mi_roffset, info.mi_rlength);
1350 		return -ENOENT;	/* -ve: OK but no match */
1351 	}
1352 
1353 	LASSERT(rc == LNET_MATCHMD_OK);
1354 
1355 	lnet_build_msg_event(msg, LNET_EVENT_GET);
1356 
1357 	reply_wmd = hdr->msg.get.return_wmd;
1358 
1359 	lnet_prep_send(msg, LNET_MSG_REPLY, info.mi_id,
1360 		       msg->msg_offset, msg->msg_wanted);
1361 
1362 	msg->msg_hdr.msg.reply.dst_wmd = reply_wmd;
1363 
1364 	if (rdma_get) {
1365 		/* The LND completes the REPLY from her recv procedure */
1366 		lnet_ni_recv(ni, msg->msg_private, msg, 0,
1367 			     msg->msg_offset, msg->msg_len, msg->msg_len);
1368 		return 0;
1369 	}
1370 
1371 	lnet_ni_recv(ni, msg->msg_private, NULL, 0, 0, 0, 0);
1372 	msg->msg_receiving = 0;
1373 
1374 	rc = lnet_send(ni->ni_nid, msg, LNET_NID_ANY);
1375 	if (rc < 0) {
1376 		/* didn't get as far as lnet_ni_send() */
1377 		CERROR("%s: Unable to send REPLY for GET from %s: %d\n",
1378 		       libcfs_nid2str(ni->ni_nid),
1379 		       libcfs_id2str(info.mi_id), rc);
1380 
1381 		lnet_finalize(ni, msg, rc);
1382 	}
1383 
1384 	return 0;
1385 }
1386 
1387 static int
lnet_parse_reply(lnet_ni_t * ni,lnet_msg_t * msg)1388 lnet_parse_reply(lnet_ni_t *ni, lnet_msg_t *msg)
1389 {
1390 	void *private = msg->msg_private;
1391 	lnet_hdr_t *hdr = &msg->msg_hdr;
1392 	lnet_process_id_t src = {0};
1393 	lnet_libmd_t *md;
1394 	int rlength;
1395 	int mlength;
1396 	int cpt;
1397 
1398 	cpt = lnet_cpt_of_cookie(hdr->msg.reply.dst_wmd.wh_object_cookie);
1399 	lnet_res_lock(cpt);
1400 
1401 	src.nid = hdr->src_nid;
1402 	src.pid = hdr->src_pid;
1403 
1404 	/* NB handles only looked up by creator (no flips) */
1405 	md = lnet_wire_handle2md(&hdr->msg.reply.dst_wmd);
1406 	if (!md || !md->md_threshold || md->md_me) {
1407 		CNETERR("%s: Dropping REPLY from %s for %s MD %#llx.%#llx\n",
1408 			libcfs_nid2str(ni->ni_nid), libcfs_id2str(src),
1409 			!md ? "invalid" : "inactive",
1410 			hdr->msg.reply.dst_wmd.wh_interface_cookie,
1411 			hdr->msg.reply.dst_wmd.wh_object_cookie);
1412 		if (md && md->md_me)
1413 			CERROR("REPLY MD also attached to portal %d\n",
1414 			       md->md_me->me_portal);
1415 
1416 		lnet_res_unlock(cpt);
1417 		return -ENOENT;	/* -ve: OK but no match */
1418 	}
1419 
1420 	LASSERT(!md->md_offset);
1421 
1422 	rlength = hdr->payload_length;
1423 	mlength = min_t(uint, rlength, md->md_length);
1424 
1425 	if (mlength < rlength &&
1426 	    !(md->md_options & LNET_MD_TRUNCATE)) {
1427 		CNETERR("%s: Dropping REPLY from %s length %d for MD %#llx would overflow (%d)\n",
1428 			libcfs_nid2str(ni->ni_nid), libcfs_id2str(src),
1429 			rlength, hdr->msg.reply.dst_wmd.wh_object_cookie,
1430 			mlength);
1431 		lnet_res_unlock(cpt);
1432 		return -ENOENT;	/* -ve: OK but no match */
1433 	}
1434 
1435 	CDEBUG(D_NET, "%s: Reply from %s of length %d/%d into md %#llx\n",
1436 	       libcfs_nid2str(ni->ni_nid), libcfs_id2str(src),
1437 	       mlength, rlength, hdr->msg.reply.dst_wmd.wh_object_cookie);
1438 
1439 	lnet_msg_attach_md(msg, md, 0, mlength);
1440 
1441 	if (mlength)
1442 		lnet_setpayloadbuffer(msg);
1443 
1444 	lnet_res_unlock(cpt);
1445 
1446 	lnet_build_msg_event(msg, LNET_EVENT_REPLY);
1447 
1448 	lnet_ni_recv(ni, private, msg, 0, 0, mlength, rlength);
1449 	return 0;
1450 }
1451 
1452 static int
lnet_parse_ack(lnet_ni_t * ni,lnet_msg_t * msg)1453 lnet_parse_ack(lnet_ni_t *ni, lnet_msg_t *msg)
1454 {
1455 	lnet_hdr_t *hdr = &msg->msg_hdr;
1456 	lnet_process_id_t src = {0};
1457 	lnet_libmd_t *md;
1458 	int cpt;
1459 
1460 	src.nid = hdr->src_nid;
1461 	src.pid = hdr->src_pid;
1462 
1463 	/* Convert ack fields to host byte order */
1464 	hdr->msg.ack.match_bits = le64_to_cpu(hdr->msg.ack.match_bits);
1465 	hdr->msg.ack.mlength = le32_to_cpu(hdr->msg.ack.mlength);
1466 
1467 	cpt = lnet_cpt_of_cookie(hdr->msg.ack.dst_wmd.wh_object_cookie);
1468 	lnet_res_lock(cpt);
1469 
1470 	/* NB handles only looked up by creator (no flips) */
1471 	md = lnet_wire_handle2md(&hdr->msg.ack.dst_wmd);
1472 	if (!md || !md->md_threshold || md->md_me) {
1473 		/* Don't moan; this is expected */
1474 		CDEBUG(D_NET,
1475 		       "%s: Dropping ACK from %s to %s MD %#llx.%#llx\n",
1476 		       libcfs_nid2str(ni->ni_nid), libcfs_id2str(src),
1477 		       !md ? "invalid" : "inactive",
1478 		       hdr->msg.ack.dst_wmd.wh_interface_cookie,
1479 		       hdr->msg.ack.dst_wmd.wh_object_cookie);
1480 		if (md && md->md_me)
1481 			CERROR("Source MD also attached to portal %d\n",
1482 			       md->md_me->me_portal);
1483 
1484 		lnet_res_unlock(cpt);
1485 		return -ENOENT;	/* -ve! */
1486 	}
1487 
1488 	CDEBUG(D_NET, "%s: ACK from %s into md %#llx\n",
1489 	       libcfs_nid2str(ni->ni_nid), libcfs_id2str(src),
1490 	       hdr->msg.ack.dst_wmd.wh_object_cookie);
1491 
1492 	lnet_msg_attach_md(msg, md, 0, 0);
1493 
1494 	lnet_res_unlock(cpt);
1495 
1496 	lnet_build_msg_event(msg, LNET_EVENT_ACK);
1497 
1498 	lnet_ni_recv(ni, msg->msg_private, msg, 0, 0, 0, msg->msg_len);
1499 	return 0;
1500 }
1501 
1502 /**
1503  * \retval LNET_CREDIT_OK	If \a msg is forwarded
1504  * \retval LNET_CREDIT_WAIT	If \a msg is blocked because w/o buffer
1505  * \retval -ve			error code
1506  */
1507 int
lnet_parse_forward_locked(lnet_ni_t * ni,lnet_msg_t * msg)1508 lnet_parse_forward_locked(lnet_ni_t *ni, lnet_msg_t *msg)
1509 {
1510 	int rc = 0;
1511 
1512 	if (!the_lnet.ln_routing)
1513 		return -ECANCELED;
1514 
1515 	if (msg->msg_rxpeer->lp_rtrcredits <= 0 ||
1516 	    lnet_msg2bufpool(msg)->rbp_credits <= 0) {
1517 		if (!ni->ni_lnd->lnd_eager_recv) {
1518 			msg->msg_rx_ready_delay = 1;
1519 		} else {
1520 			lnet_net_unlock(msg->msg_rx_cpt);
1521 			rc = lnet_ni_eager_recv(ni, msg);
1522 			lnet_net_lock(msg->msg_rx_cpt);
1523 		}
1524 	}
1525 
1526 	if (!rc)
1527 		rc = lnet_post_routed_recv_locked(msg, 0);
1528 	return rc;
1529 }
1530 
1531 int
lnet_parse_local(lnet_ni_t * ni,lnet_msg_t * msg)1532 lnet_parse_local(lnet_ni_t *ni, lnet_msg_t *msg)
1533 {
1534 	int rc;
1535 
1536 	switch (msg->msg_type) {
1537 	case LNET_MSG_ACK:
1538 		rc = lnet_parse_ack(ni, msg);
1539 		break;
1540 	case LNET_MSG_PUT:
1541 		rc = lnet_parse_put(ni, msg);
1542 		break;
1543 	case LNET_MSG_GET:
1544 		rc = lnet_parse_get(ni, msg, msg->msg_rdma_get);
1545 		break;
1546 	case LNET_MSG_REPLY:
1547 		rc = lnet_parse_reply(ni, msg);
1548 		break;
1549 	default: /* prevent an unused label if !kernel */
1550 		LASSERT(0);
1551 		return -EPROTO;
1552 	}
1553 
1554 	LASSERT(!rc || rc == -ENOENT);
1555 	return rc;
1556 }
1557 
1558 char *
lnet_msgtyp2str(int type)1559 lnet_msgtyp2str(int type)
1560 {
1561 	switch (type) {
1562 	case LNET_MSG_ACK:
1563 		return "ACK";
1564 	case LNET_MSG_PUT:
1565 		return "PUT";
1566 	case LNET_MSG_GET:
1567 		return "GET";
1568 	case LNET_MSG_REPLY:
1569 		return "REPLY";
1570 	case LNET_MSG_HELLO:
1571 		return "HELLO";
1572 	default:
1573 		return "<UNKNOWN>";
1574 	}
1575 }
1576 
1577 void
lnet_print_hdr(lnet_hdr_t * hdr)1578 lnet_print_hdr(lnet_hdr_t *hdr)
1579 {
1580 	lnet_process_id_t src = {0};
1581 	lnet_process_id_t dst = {0};
1582 	char *type_str = lnet_msgtyp2str(hdr->type);
1583 
1584 	src.nid = hdr->src_nid;
1585 	src.pid = hdr->src_pid;
1586 
1587 	dst.nid = hdr->dest_nid;
1588 	dst.pid = hdr->dest_pid;
1589 
1590 	CWARN("P3 Header at %p of type %s\n", hdr, type_str);
1591 	CWARN("    From %s\n", libcfs_id2str(src));
1592 	CWARN("    To   %s\n", libcfs_id2str(dst));
1593 
1594 	switch (hdr->type) {
1595 	default:
1596 		break;
1597 
1598 	case LNET_MSG_PUT:
1599 		CWARN("    Ptl index %d, ack md %#llx.%#llx, match bits %llu\n",
1600 		      hdr->msg.put.ptl_index,
1601 		      hdr->msg.put.ack_wmd.wh_interface_cookie,
1602 		      hdr->msg.put.ack_wmd.wh_object_cookie,
1603 		      hdr->msg.put.match_bits);
1604 		CWARN("    Length %d, offset %d, hdr data %#llx\n",
1605 		      hdr->payload_length, hdr->msg.put.offset,
1606 		      hdr->msg.put.hdr_data);
1607 		break;
1608 
1609 	case LNET_MSG_GET:
1610 		CWARN("    Ptl index %d, return md %#llx.%#llx, match bits %llu\n",
1611 		      hdr->msg.get.ptl_index,
1612 		      hdr->msg.get.return_wmd.wh_interface_cookie,
1613 		      hdr->msg.get.return_wmd.wh_object_cookie,
1614 		      hdr->msg.get.match_bits);
1615 		CWARN("    Length %d, src offset %d\n",
1616 		      hdr->msg.get.sink_length,
1617 		      hdr->msg.get.src_offset);
1618 		break;
1619 
1620 	case LNET_MSG_ACK:
1621 		CWARN("    dst md %#llx.%#llx, manipulated length %d\n",
1622 		      hdr->msg.ack.dst_wmd.wh_interface_cookie,
1623 		      hdr->msg.ack.dst_wmd.wh_object_cookie,
1624 		      hdr->msg.ack.mlength);
1625 		break;
1626 
1627 	case LNET_MSG_REPLY:
1628 		CWARN("    dst md %#llx.%#llx, length %d\n",
1629 		      hdr->msg.reply.dst_wmd.wh_interface_cookie,
1630 		      hdr->msg.reply.dst_wmd.wh_object_cookie,
1631 		      hdr->payload_length);
1632 	}
1633 }
1634 
1635 int
lnet_parse(lnet_ni_t * ni,lnet_hdr_t * hdr,lnet_nid_t from_nid,void * private,int rdma_req)1636 lnet_parse(lnet_ni_t *ni, lnet_hdr_t *hdr, lnet_nid_t from_nid,
1637 	   void *private, int rdma_req)
1638 {
1639 	int rc = 0;
1640 	int cpt;
1641 	int for_me;
1642 	struct lnet_msg *msg;
1643 	lnet_pid_t dest_pid;
1644 	lnet_nid_t dest_nid;
1645 	lnet_nid_t src_nid;
1646 	__u32 payload_length;
1647 	__u32 type;
1648 
1649 	LASSERT(!in_interrupt());
1650 
1651 	type = le32_to_cpu(hdr->type);
1652 	src_nid = le64_to_cpu(hdr->src_nid);
1653 	dest_nid = le64_to_cpu(hdr->dest_nid);
1654 	dest_pid = le32_to_cpu(hdr->dest_pid);
1655 	payload_length = le32_to_cpu(hdr->payload_length);
1656 
1657 	for_me = (ni->ni_nid == dest_nid);
1658 	cpt = lnet_cpt_of_nid(from_nid);
1659 
1660 	switch (type) {
1661 	case LNET_MSG_ACK:
1662 	case LNET_MSG_GET:
1663 		if (payload_length > 0) {
1664 			CERROR("%s, src %s: bad %s payload %d (0 expected)\n",
1665 			       libcfs_nid2str(from_nid),
1666 			       libcfs_nid2str(src_nid),
1667 			       lnet_msgtyp2str(type), payload_length);
1668 			return -EPROTO;
1669 		}
1670 		break;
1671 
1672 	case LNET_MSG_PUT:
1673 	case LNET_MSG_REPLY:
1674 		if (payload_length >
1675 		   (__u32)(for_me ? LNET_MAX_PAYLOAD : LNET_MTU)) {
1676 			CERROR("%s, src %s: bad %s payload %d (%d max expected)\n",
1677 			       libcfs_nid2str(from_nid),
1678 			       libcfs_nid2str(src_nid),
1679 			       lnet_msgtyp2str(type),
1680 			       payload_length,
1681 			       for_me ? LNET_MAX_PAYLOAD : LNET_MTU);
1682 			return -EPROTO;
1683 		}
1684 		break;
1685 
1686 	default:
1687 		CERROR("%s, src %s: Bad message type 0x%x\n",
1688 		       libcfs_nid2str(from_nid),
1689 		       libcfs_nid2str(src_nid), type);
1690 		return -EPROTO;
1691 	}
1692 
1693 	if (the_lnet.ln_routing &&
1694 	    ni->ni_last_alive != ktime_get_real_seconds()) {
1695 		/* NB: so far here is the only place to set NI status to "up */
1696 		lnet_ni_lock(ni);
1697 		ni->ni_last_alive = ktime_get_real_seconds();
1698 		if (ni->ni_status &&
1699 		    ni->ni_status->ns_status == LNET_NI_STATUS_DOWN)
1700 			ni->ni_status->ns_status = LNET_NI_STATUS_UP;
1701 		lnet_ni_unlock(ni);
1702 	}
1703 
1704 	/*
1705 	 * Regard a bad destination NID as a protocol error.  Senders should
1706 	 * know what they're doing; if they don't they're misconfigured, buggy
1707 	 * or malicious so we chop them off at the knees :)
1708 	 */
1709 	if (!for_me) {
1710 		if (LNET_NIDNET(dest_nid) == LNET_NIDNET(ni->ni_nid)) {
1711 			/* should have gone direct */
1712 			CERROR("%s, src %s: Bad dest nid %s (should have been sent direct)\n",
1713 			       libcfs_nid2str(from_nid),
1714 			       libcfs_nid2str(src_nid),
1715 			       libcfs_nid2str(dest_nid));
1716 			return -EPROTO;
1717 		}
1718 
1719 		if (lnet_islocalnid(dest_nid)) {
1720 			/*
1721 			 * dest is another local NI; sender should have used
1722 			 * this node's NID on its own network
1723 			 */
1724 			CERROR("%s, src %s: Bad dest nid %s (it's my nid but on a different network)\n",
1725 			       libcfs_nid2str(from_nid),
1726 			       libcfs_nid2str(src_nid),
1727 			       libcfs_nid2str(dest_nid));
1728 			return -EPROTO;
1729 		}
1730 
1731 		if (rdma_req && type == LNET_MSG_GET) {
1732 			CERROR("%s, src %s: Bad optimized GET for %s (final destination must be me)\n",
1733 			       libcfs_nid2str(from_nid),
1734 			       libcfs_nid2str(src_nid),
1735 			       libcfs_nid2str(dest_nid));
1736 			return -EPROTO;
1737 		}
1738 
1739 		if (!the_lnet.ln_routing) {
1740 			CERROR("%s, src %s: Dropping message for %s (routing not enabled)\n",
1741 			       libcfs_nid2str(from_nid),
1742 			       libcfs_nid2str(src_nid),
1743 			       libcfs_nid2str(dest_nid));
1744 			goto drop;
1745 		}
1746 	}
1747 
1748 	/*
1749 	 * Message looks OK; we're not going to return an error, so we MUST
1750 	 * call back lnd_recv() come what may...
1751 	 */
1752 	if (!list_empty(&the_lnet.ln_test_peers) && /* normally we don't */
1753 	    fail_peer(src_nid, 0)) {	     /* shall we now? */
1754 		CERROR("%s, src %s: Dropping %s to simulate failure\n",
1755 		       libcfs_nid2str(from_nid), libcfs_nid2str(src_nid),
1756 		       lnet_msgtyp2str(type));
1757 		goto drop;
1758 	}
1759 
1760 	if (!list_empty(&the_lnet.ln_drop_rules) &&
1761 	    lnet_drop_rule_match(hdr)) {
1762 		CDEBUG(D_NET, "%s, src %s, dst %s: Dropping %s to simulate silent message loss\n",
1763 		       libcfs_nid2str(from_nid), libcfs_nid2str(src_nid),
1764 		       libcfs_nid2str(dest_nid), lnet_msgtyp2str(type));
1765 		goto drop;
1766 	}
1767 
1768 	msg = lnet_msg_alloc();
1769 	if (!msg) {
1770 		CERROR("%s, src %s: Dropping %s (out of memory)\n",
1771 		       libcfs_nid2str(from_nid), libcfs_nid2str(src_nid),
1772 		       lnet_msgtyp2str(type));
1773 		goto drop;
1774 	}
1775 
1776 	/* msg zeroed in lnet_msg_alloc;
1777 	 * i.e. flags all clear, pointers NULL etc
1778 	 */
1779 	msg->msg_type = type;
1780 	msg->msg_private = private;
1781 	msg->msg_receiving = 1;
1782 	msg->msg_rdma_get = rdma_req;
1783 	msg->msg_wanted = payload_length;
1784 	msg->msg_len = payload_length;
1785 	msg->msg_offset = 0;
1786 	msg->msg_hdr = *hdr;
1787 	/* for building message event */
1788 	msg->msg_from = from_nid;
1789 	if (!for_me) {
1790 		msg->msg_target.pid	= dest_pid;
1791 		msg->msg_target.nid	= dest_nid;
1792 		msg->msg_routing	= 1;
1793 
1794 	} else {
1795 		/* convert common msg->hdr fields to host byteorder */
1796 		msg->msg_hdr.type	= type;
1797 		msg->msg_hdr.src_nid	= src_nid;
1798 		msg->msg_hdr.src_pid	= le32_to_cpu(msg->msg_hdr.src_pid);
1799 		msg->msg_hdr.dest_nid	= dest_nid;
1800 		msg->msg_hdr.dest_pid	= dest_pid;
1801 		msg->msg_hdr.payload_length = payload_length;
1802 	}
1803 
1804 	lnet_net_lock(cpt);
1805 	rc = lnet_nid2peer_locked(&msg->msg_rxpeer, from_nid, cpt);
1806 	if (rc) {
1807 		lnet_net_unlock(cpt);
1808 		CERROR("%s, src %s: Dropping %s (error %d looking up sender)\n",
1809 		       libcfs_nid2str(from_nid), libcfs_nid2str(src_nid),
1810 		       lnet_msgtyp2str(type), rc);
1811 		lnet_msg_free(msg);
1812 		if (rc == -ESHUTDOWN)
1813 			/* We are shutting down. Don't do anything more */
1814 			return 0;
1815 		goto drop;
1816 	}
1817 
1818 	if (lnet_isrouter(msg->msg_rxpeer)) {
1819 		lnet_peer_set_alive(msg->msg_rxpeer);
1820 		if (avoid_asym_router_failure &&
1821 		    LNET_NIDNET(src_nid) != LNET_NIDNET(from_nid)) {
1822 			/* received a remote message from router, update
1823 			 * remote NI status on this router.
1824 			 * NB: multi-hop routed message will be ignored.
1825 			 */
1826 			lnet_router_ni_update_locked(msg->msg_rxpeer,
1827 						     LNET_NIDNET(src_nid));
1828 		}
1829 	}
1830 
1831 	lnet_msg_commit(msg, cpt);
1832 
1833 	/* message delay simulation */
1834 	if (unlikely(!list_empty(&the_lnet.ln_delay_rules) &&
1835 		     lnet_delay_rule_match_locked(hdr, msg))) {
1836 		lnet_net_unlock(cpt);
1837 		return 0;
1838 	}
1839 
1840 	if (!for_me) {
1841 		rc = lnet_parse_forward_locked(ni, msg);
1842 		lnet_net_unlock(cpt);
1843 
1844 		if (rc < 0)
1845 			goto free_drop;
1846 
1847 		if (rc == LNET_CREDIT_OK) {
1848 			lnet_ni_recv(ni, msg->msg_private, msg, 0,
1849 				     0, payload_length, payload_length);
1850 		}
1851 		return 0;
1852 	}
1853 
1854 	lnet_net_unlock(cpt);
1855 
1856 	rc = lnet_parse_local(ni, msg);
1857 	if (rc)
1858 		goto free_drop;
1859 	return 0;
1860 
1861  free_drop:
1862 	LASSERT(!msg->msg_md);
1863 	lnet_finalize(ni, msg, rc);
1864 
1865  drop:
1866 	lnet_drop_message(ni, cpt, private, payload_length);
1867 	return 0;
1868 }
1869 EXPORT_SYMBOL(lnet_parse);
1870 
1871 void
lnet_drop_delayed_msg_list(struct list_head * head,char * reason)1872 lnet_drop_delayed_msg_list(struct list_head *head, char *reason)
1873 {
1874 	while (!list_empty(head)) {
1875 		lnet_process_id_t id = {0};
1876 		lnet_msg_t *msg;
1877 
1878 		msg = list_entry(head->next, lnet_msg_t, msg_list);
1879 		list_del(&msg->msg_list);
1880 
1881 		id.nid = msg->msg_hdr.src_nid;
1882 		id.pid = msg->msg_hdr.src_pid;
1883 
1884 		LASSERT(!msg->msg_md);
1885 		LASSERT(msg->msg_rx_delayed);
1886 		LASSERT(msg->msg_rxpeer);
1887 		LASSERT(msg->msg_hdr.type == LNET_MSG_PUT);
1888 
1889 		CWARN("Dropping delayed PUT from %s portal %d match %llu offset %d length %d: %s\n",
1890 		      libcfs_id2str(id),
1891 		      msg->msg_hdr.msg.put.ptl_index,
1892 		      msg->msg_hdr.msg.put.match_bits,
1893 		      msg->msg_hdr.msg.put.offset,
1894 		      msg->msg_hdr.payload_length, reason);
1895 
1896 		/*
1897 		 * NB I can't drop msg's ref on msg_rxpeer until after I've
1898 		 * called lnet_drop_message(), so I just hang onto msg as well
1899 		 * until that's done
1900 		 */
1901 		lnet_drop_message(msg->msg_rxpeer->lp_ni,
1902 				  msg->msg_rxpeer->lp_cpt,
1903 				  msg->msg_private, msg->msg_len);
1904 		/*
1905 		 * NB: message will not generate event because w/o attached MD,
1906 		 * but we still should give error code so lnet_msg_decommit()
1907 		 * can skip counters operations and other checks.
1908 		 */
1909 		lnet_finalize(msg->msg_rxpeer->lp_ni, msg, -ENOENT);
1910 	}
1911 }
1912 
1913 void
lnet_recv_delayed_msg_list(struct list_head * head)1914 lnet_recv_delayed_msg_list(struct list_head *head)
1915 {
1916 	while (!list_empty(head)) {
1917 		lnet_msg_t *msg;
1918 		lnet_process_id_t id;
1919 
1920 		msg = list_entry(head->next, lnet_msg_t, msg_list);
1921 		list_del(&msg->msg_list);
1922 
1923 		/*
1924 		 * md won't disappear under me, since each msg
1925 		 * holds a ref on it
1926 		 */
1927 		id.nid = msg->msg_hdr.src_nid;
1928 		id.pid = msg->msg_hdr.src_pid;
1929 
1930 		LASSERT(msg->msg_rx_delayed);
1931 		LASSERT(msg->msg_md);
1932 		LASSERT(msg->msg_rxpeer);
1933 		LASSERT(msg->msg_hdr.type == LNET_MSG_PUT);
1934 
1935 		CDEBUG(D_NET, "Resuming delayed PUT from %s portal %d match %llu offset %d length %d.\n",
1936 		       libcfs_id2str(id), msg->msg_hdr.msg.put.ptl_index,
1937 		       msg->msg_hdr.msg.put.match_bits,
1938 		       msg->msg_hdr.msg.put.offset,
1939 		       msg->msg_hdr.payload_length);
1940 
1941 		lnet_recv_put(msg->msg_rxpeer->lp_ni, msg);
1942 	}
1943 }
1944 
1945 /**
1946  * Initiate an asynchronous PUT operation.
1947  *
1948  * There are several events associated with a PUT: completion of the send on
1949  * the initiator node (LNET_EVENT_SEND), and when the send completes
1950  * successfully, the receipt of an acknowledgment (LNET_EVENT_ACK) indicating
1951  * that the operation was accepted by the target. The event LNET_EVENT_PUT is
1952  * used at the target node to indicate the completion of incoming data
1953  * delivery.
1954  *
1955  * The local events will be logged in the EQ associated with the MD pointed to
1956  * by \a mdh handle. Using a MD without an associated EQ results in these
1957  * events being discarded. In this case, the caller must have another
1958  * mechanism (e.g., a higher level protocol) for determining when it is safe
1959  * to modify the memory region associated with the MD.
1960  *
1961  * Note that LNet does not guarantee the order of LNET_EVENT_SEND and
1962  * LNET_EVENT_ACK, though intuitively ACK should happen after SEND.
1963  *
1964  * \param self Indicates the NID of a local interface through which to send
1965  * the PUT request. Use LNET_NID_ANY to let LNet choose one by itself.
1966  * \param mdh A handle for the MD that describes the memory to be sent. The MD
1967  * must be "free floating" (See LNetMDBind()).
1968  * \param ack Controls whether an acknowledgment is requested.
1969  * Acknowledgments are only sent when they are requested by the initiating
1970  * process and the target MD enables them.
1971  * \param target A process identifier for the target process.
1972  * \param portal The index in the \a target's portal table.
1973  * \param match_bits The match bits to use for MD selection at the target
1974  * process.
1975  * \param offset The offset into the target MD (only used when the target
1976  * MD has the LNET_MD_MANAGE_REMOTE option set).
1977  * \param hdr_data 64 bits of user data that can be included in the message
1978  * header. This data is written to an event queue entry at the target if an
1979  * EQ is present on the matching MD.
1980  *
1981  * \retval  0      Success, and only in this case events will be generated
1982  * and logged to EQ (if it exists).
1983  * \retval -EIO    Simulated failure.
1984  * \retval -ENOMEM Memory allocation failure.
1985  * \retval -ENOENT Invalid MD object.
1986  *
1987  * \see lnet_event_t::hdr_data and lnet_event_kind_t.
1988  */
1989 int
LNetPut(lnet_nid_t self,lnet_handle_md_t mdh,lnet_ack_req_t ack,lnet_process_id_t target,unsigned int portal,__u64 match_bits,unsigned int offset,__u64 hdr_data)1990 LNetPut(lnet_nid_t self, lnet_handle_md_t mdh, lnet_ack_req_t ack,
1991 	lnet_process_id_t target, unsigned int portal,
1992 	__u64 match_bits, unsigned int offset,
1993 	__u64 hdr_data)
1994 {
1995 	struct lnet_msg *msg;
1996 	struct lnet_libmd *md;
1997 	int cpt;
1998 	int rc;
1999 
2000 	LASSERT(the_lnet.ln_refcount > 0);
2001 
2002 	if (!list_empty(&the_lnet.ln_test_peers) && /* normally we don't */
2003 	    fail_peer(target.nid, 1)) { /* shall we now? */
2004 		CERROR("Dropping PUT to %s: simulated failure\n",
2005 		       libcfs_id2str(target));
2006 		return -EIO;
2007 	}
2008 
2009 	msg = lnet_msg_alloc();
2010 	if (!msg) {
2011 		CERROR("Dropping PUT to %s: ENOMEM on lnet_msg_t\n",
2012 		       libcfs_id2str(target));
2013 		return -ENOMEM;
2014 	}
2015 	msg->msg_vmflush = !!memory_pressure_get();
2016 
2017 	cpt = lnet_cpt_of_cookie(mdh.cookie);
2018 	lnet_res_lock(cpt);
2019 
2020 	md = lnet_handle2md(&mdh);
2021 	if (!md || !md->md_threshold || md->md_me) {
2022 		CERROR("Dropping PUT (%llu:%d:%s): MD (%d) invalid\n",
2023 		       match_bits, portal, libcfs_id2str(target),
2024 		       !md ? -1 : md->md_threshold);
2025 		if (md && md->md_me)
2026 			CERROR("Source MD also attached to portal %d\n",
2027 			       md->md_me->me_portal);
2028 		lnet_res_unlock(cpt);
2029 
2030 		lnet_msg_free(msg);
2031 		return -ENOENT;
2032 	}
2033 
2034 	CDEBUG(D_NET, "LNetPut -> %s\n", libcfs_id2str(target));
2035 
2036 	lnet_msg_attach_md(msg, md, 0, 0);
2037 
2038 	lnet_prep_send(msg, LNET_MSG_PUT, target, 0, md->md_length);
2039 
2040 	msg->msg_hdr.msg.put.match_bits = cpu_to_le64(match_bits);
2041 	msg->msg_hdr.msg.put.ptl_index = cpu_to_le32(portal);
2042 	msg->msg_hdr.msg.put.offset = cpu_to_le32(offset);
2043 	msg->msg_hdr.msg.put.hdr_data = hdr_data;
2044 
2045 	/* NB handles only looked up by creator (no flips) */
2046 	if (ack == LNET_ACK_REQ) {
2047 		msg->msg_hdr.msg.put.ack_wmd.wh_interface_cookie =
2048 			the_lnet.ln_interface_cookie;
2049 		msg->msg_hdr.msg.put.ack_wmd.wh_object_cookie =
2050 			md->md_lh.lh_cookie;
2051 	} else {
2052 		msg->msg_hdr.msg.put.ack_wmd.wh_interface_cookie =
2053 			LNET_WIRE_HANDLE_COOKIE_NONE;
2054 		msg->msg_hdr.msg.put.ack_wmd.wh_object_cookie =
2055 			LNET_WIRE_HANDLE_COOKIE_NONE;
2056 	}
2057 
2058 	lnet_res_unlock(cpt);
2059 
2060 	lnet_build_msg_event(msg, LNET_EVENT_SEND);
2061 
2062 	rc = lnet_send(self, msg, LNET_NID_ANY);
2063 	if (rc) {
2064 		CNETERR("Error sending PUT to %s: %d\n",
2065 			libcfs_id2str(target), rc);
2066 		lnet_finalize(NULL, msg, rc);
2067 	}
2068 
2069 	/* completion will be signalled by an event */
2070 	return 0;
2071 }
2072 EXPORT_SYMBOL(LNetPut);
2073 
2074 lnet_msg_t *
lnet_create_reply_msg(lnet_ni_t * ni,lnet_msg_t * getmsg)2075 lnet_create_reply_msg(lnet_ni_t *ni, lnet_msg_t *getmsg)
2076 {
2077 	/*
2078 	 * The LND can DMA direct to the GET md (i.e. no REPLY msg).  This
2079 	 * returns a msg for the LND to pass to lnet_finalize() when the sink
2080 	 * data has been received.
2081 	 *
2082 	 * CAVEAT EMPTOR: 'getmsg' is the original GET, which is freed when
2083 	 * lnet_finalize() is called on it, so the LND must call this first
2084 	 */
2085 	struct lnet_msg *msg = lnet_msg_alloc();
2086 	struct lnet_libmd *getmd = getmsg->msg_md;
2087 	lnet_process_id_t peer_id = getmsg->msg_target;
2088 	int cpt;
2089 
2090 	LASSERT(!getmsg->msg_target_is_router);
2091 	LASSERT(!getmsg->msg_routing);
2092 
2093 	if (!msg) {
2094 		CERROR("%s: Dropping REPLY from %s: can't allocate msg\n",
2095 		       libcfs_nid2str(ni->ni_nid), libcfs_id2str(peer_id));
2096 		goto drop;
2097 	}
2098 
2099 	cpt = lnet_cpt_of_cookie(getmd->md_lh.lh_cookie);
2100 	lnet_res_lock(cpt);
2101 
2102 	LASSERT(getmd->md_refcount > 0);
2103 
2104 	if (!getmd->md_threshold) {
2105 		CERROR("%s: Dropping REPLY from %s for inactive MD %p\n",
2106 		       libcfs_nid2str(ni->ni_nid), libcfs_id2str(peer_id),
2107 		       getmd);
2108 		lnet_res_unlock(cpt);
2109 		goto drop;
2110 	}
2111 
2112 	LASSERT(!getmd->md_offset);
2113 
2114 	CDEBUG(D_NET, "%s: Reply from %s md %p\n",
2115 	       libcfs_nid2str(ni->ni_nid), libcfs_id2str(peer_id), getmd);
2116 
2117 	/* setup information for lnet_build_msg_event */
2118 	msg->msg_from = peer_id.nid;
2119 	msg->msg_type = LNET_MSG_GET; /* flag this msg as an "optimized" GET */
2120 	msg->msg_hdr.src_nid = peer_id.nid;
2121 	msg->msg_hdr.payload_length = getmd->md_length;
2122 	msg->msg_receiving = 1; /* required by lnet_msg_attach_md */
2123 
2124 	lnet_msg_attach_md(msg, getmd, getmd->md_offset, getmd->md_length);
2125 	lnet_res_unlock(cpt);
2126 
2127 	cpt = lnet_cpt_of_nid(peer_id.nid);
2128 
2129 	lnet_net_lock(cpt);
2130 	lnet_msg_commit(msg, cpt);
2131 	lnet_net_unlock(cpt);
2132 
2133 	lnet_build_msg_event(msg, LNET_EVENT_REPLY);
2134 
2135 	return msg;
2136 
2137  drop:
2138 	cpt = lnet_cpt_of_nid(peer_id.nid);
2139 
2140 	lnet_net_lock(cpt);
2141 	the_lnet.ln_counters[cpt]->drop_count++;
2142 	the_lnet.ln_counters[cpt]->drop_length += getmd->md_length;
2143 	lnet_net_unlock(cpt);
2144 
2145 	if (msg)
2146 		lnet_msg_free(msg);
2147 
2148 	return NULL;
2149 }
2150 EXPORT_SYMBOL(lnet_create_reply_msg);
2151 
2152 void
lnet_set_reply_msg_len(lnet_ni_t * ni,lnet_msg_t * reply,unsigned int len)2153 lnet_set_reply_msg_len(lnet_ni_t *ni, lnet_msg_t *reply, unsigned int len)
2154 {
2155 	/*
2156 	 * Set the REPLY length, now the RDMA that elides the REPLY message has
2157 	 * completed and I know it.
2158 	 */
2159 	LASSERT(reply);
2160 	LASSERT(reply->msg_type == LNET_MSG_GET);
2161 	LASSERT(reply->msg_ev.type == LNET_EVENT_REPLY);
2162 
2163 	/*
2164 	 * NB I trusted my peer to RDMA.  If she tells me she's written beyond
2165 	 * the end of my buffer, I might as well be dead.
2166 	 */
2167 	LASSERT(len <= reply->msg_ev.mlength);
2168 
2169 	reply->msg_ev.mlength = len;
2170 }
2171 EXPORT_SYMBOL(lnet_set_reply_msg_len);
2172 
2173 /**
2174  * Initiate an asynchronous GET operation.
2175  *
2176  * On the initiator node, an LNET_EVENT_SEND is logged when the GET request
2177  * is sent, and an LNET_EVENT_REPLY is logged when the data returned from
2178  * the target node in the REPLY has been written to local MD.
2179  *
2180  * On the target node, an LNET_EVENT_GET is logged when the GET request
2181  * arrives and is accepted into a MD.
2182  *
2183  * \param self,target,portal,match_bits,offset See the discussion in LNetPut().
2184  * \param mdh A handle for the MD that describes the memory into which the
2185  * requested data will be received. The MD must be "free floating"
2186  * (See LNetMDBind()).
2187  *
2188  * \retval  0      Success, and only in this case events will be generated
2189  * and logged to EQ (if it exists) of the MD.
2190  * \retval -EIO    Simulated failure.
2191  * \retval -ENOMEM Memory allocation failure.
2192  * \retval -ENOENT Invalid MD object.
2193  */
2194 int
LNetGet(lnet_nid_t self,lnet_handle_md_t mdh,lnet_process_id_t target,unsigned int portal,__u64 match_bits,unsigned int offset)2195 LNetGet(lnet_nid_t self, lnet_handle_md_t mdh,
2196 	lnet_process_id_t target, unsigned int portal,
2197 	__u64 match_bits, unsigned int offset)
2198 {
2199 	struct lnet_msg *msg;
2200 	struct lnet_libmd *md;
2201 	int cpt;
2202 	int rc;
2203 
2204 	LASSERT(the_lnet.ln_refcount > 0);
2205 
2206 	if (!list_empty(&the_lnet.ln_test_peers) && /* normally we don't */
2207 	    fail_peer(target.nid, 1)) {	  /* shall we now? */
2208 		CERROR("Dropping GET to %s: simulated failure\n",
2209 		       libcfs_id2str(target));
2210 		return -EIO;
2211 	}
2212 
2213 	msg = lnet_msg_alloc();
2214 	if (!msg) {
2215 		CERROR("Dropping GET to %s: ENOMEM on lnet_msg_t\n",
2216 		       libcfs_id2str(target));
2217 		return -ENOMEM;
2218 	}
2219 
2220 	cpt = lnet_cpt_of_cookie(mdh.cookie);
2221 	lnet_res_lock(cpt);
2222 
2223 	md = lnet_handle2md(&mdh);
2224 	if (!md || !md->md_threshold || md->md_me) {
2225 		CERROR("Dropping GET (%llu:%d:%s): MD (%d) invalid\n",
2226 		       match_bits, portal, libcfs_id2str(target),
2227 		       !md ? -1 : md->md_threshold);
2228 		if (md && md->md_me)
2229 			CERROR("REPLY MD also attached to portal %d\n",
2230 			       md->md_me->me_portal);
2231 
2232 		lnet_res_unlock(cpt);
2233 
2234 		lnet_msg_free(msg);
2235 		return -ENOENT;
2236 	}
2237 
2238 	CDEBUG(D_NET, "LNetGet -> %s\n", libcfs_id2str(target));
2239 
2240 	lnet_msg_attach_md(msg, md, 0, 0);
2241 
2242 	lnet_prep_send(msg, LNET_MSG_GET, target, 0, 0);
2243 
2244 	msg->msg_hdr.msg.get.match_bits = cpu_to_le64(match_bits);
2245 	msg->msg_hdr.msg.get.ptl_index = cpu_to_le32(portal);
2246 	msg->msg_hdr.msg.get.src_offset = cpu_to_le32(offset);
2247 	msg->msg_hdr.msg.get.sink_length = cpu_to_le32(md->md_length);
2248 
2249 	/* NB handles only looked up by creator (no flips) */
2250 	msg->msg_hdr.msg.get.return_wmd.wh_interface_cookie =
2251 		the_lnet.ln_interface_cookie;
2252 	msg->msg_hdr.msg.get.return_wmd.wh_object_cookie =
2253 		md->md_lh.lh_cookie;
2254 
2255 	lnet_res_unlock(cpt);
2256 
2257 	lnet_build_msg_event(msg, LNET_EVENT_SEND);
2258 
2259 	rc = lnet_send(self, msg, LNET_NID_ANY);
2260 	if (rc < 0) {
2261 		CNETERR("Error sending GET to %s: %d\n",
2262 			libcfs_id2str(target), rc);
2263 		lnet_finalize(NULL, msg, rc);
2264 	}
2265 
2266 	/* completion will be signalled by an event */
2267 	return 0;
2268 }
2269 EXPORT_SYMBOL(LNetGet);
2270 
2271 /**
2272  * Calculate distance to node at \a dstnid.
2273  *
2274  * \param dstnid Target NID.
2275  * \param srcnidp If not NULL, NID of the local interface to reach \a dstnid
2276  * is saved here.
2277  * \param orderp If not NULL, order of the route to reach \a dstnid is saved
2278  * here.
2279  *
2280  * \retval 0 If \a dstnid belongs to a local interface, and reserved option
2281  * local_nid_dist_zero is set, which is the default.
2282  * \retval positives Distance to target NID, i.e. number of hops plus one.
2283  * \retval -EHOSTUNREACH If \a dstnid is not reachable.
2284  */
2285 int
LNetDist(lnet_nid_t dstnid,lnet_nid_t * srcnidp,__u32 * orderp)2286 LNetDist(lnet_nid_t dstnid, lnet_nid_t *srcnidp, __u32 *orderp)
2287 {
2288 	struct list_head *e;
2289 	struct lnet_ni *ni;
2290 	lnet_remotenet_t *rnet;
2291 	__u32 dstnet = LNET_NIDNET(dstnid);
2292 	int hops;
2293 	int cpt;
2294 	__u32 order = 2;
2295 	struct list_head *rn_list;
2296 
2297 	/*
2298 	 * if !local_nid_dist_zero, I don't return a distance of 0 ever
2299 	 * (when lustre sees a distance of 0, it substitutes 0@lo), so I
2300 	 * keep order 0 free for 0@lo and order 1 free for a local NID
2301 	 * match
2302 	 */
2303 	LASSERT(the_lnet.ln_refcount > 0);
2304 
2305 	cpt = lnet_net_lock_current();
2306 
2307 	list_for_each(e, &the_lnet.ln_nis) {
2308 		ni = list_entry(e, lnet_ni_t, ni_list);
2309 
2310 		if (ni->ni_nid == dstnid) {
2311 			if (srcnidp)
2312 				*srcnidp = dstnid;
2313 			if (orderp) {
2314 				if (LNET_NETTYP(LNET_NIDNET(dstnid)) == LOLND)
2315 					*orderp = 0;
2316 				else
2317 					*orderp = 1;
2318 			}
2319 			lnet_net_unlock(cpt);
2320 
2321 			return local_nid_dist_zero ? 0 : 1;
2322 		}
2323 
2324 		if (LNET_NIDNET(ni->ni_nid) == dstnet) {
2325 			/*
2326 			 * Check if ni was originally created in
2327 			 * current net namespace.
2328 			 * If not, assign order above 0xffff0000,
2329 			 * to make this ni not a priority.
2330 			 */
2331 			if (!net_eq(ni->ni_net_ns, current->nsproxy->net_ns))
2332 				order += 0xffff0000;
2333 
2334 			if (srcnidp)
2335 				*srcnidp = ni->ni_nid;
2336 			if (orderp)
2337 				*orderp = order;
2338 			lnet_net_unlock(cpt);
2339 			return 1;
2340 		}
2341 
2342 		order++;
2343 	}
2344 
2345 	rn_list = lnet_net2rnethash(dstnet);
2346 	list_for_each(e, rn_list) {
2347 		rnet = list_entry(e, lnet_remotenet_t, lrn_list);
2348 
2349 		if (rnet->lrn_net == dstnet) {
2350 			lnet_route_t *route;
2351 			lnet_route_t *shortest = NULL;
2352 			__u32 shortest_hops = LNET_UNDEFINED_HOPS;
2353 			__u32 route_hops;
2354 
2355 			LASSERT(!list_empty(&rnet->lrn_routes));
2356 
2357 			list_for_each_entry(route, &rnet->lrn_routes,
2358 					    lr_list) {
2359 				route_hops = route->lr_hops;
2360 				if (route_hops == LNET_UNDEFINED_HOPS)
2361 					route_hops = 1;
2362 				if (!shortest ||
2363 				    route_hops < shortest_hops) {
2364 					shortest = route;
2365 					shortest_hops = route_hops;
2366 				}
2367 			}
2368 
2369 			LASSERT(shortest);
2370 			hops = shortest_hops;
2371 			if (srcnidp)
2372 				*srcnidp = shortest->lr_gateway->lp_ni->ni_nid;
2373 			if (orderp)
2374 				*orderp = order;
2375 			lnet_net_unlock(cpt);
2376 			return hops + 1;
2377 		}
2378 		order++;
2379 	}
2380 
2381 	lnet_net_unlock(cpt);
2382 	return -EHOSTUNREACH;
2383 }
2384 EXPORT_SYMBOL(LNetDist);
2385