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1 /*
2  * Copyright (c) 2006 Oracle.  All rights reserved.
3  *
4  * This software is available to you under a choice of one of two
5  * licenses.  You may choose to be licensed under the terms of the GNU
6  * General Public License (GPL) Version 2, available from the file
7  * COPYING in the main directory of this source tree, or the
8  * OpenIB.org BSD license below:
9  *
10  *     Redistribution and use in source and binary forms, with or
11  *     without modification, are permitted provided that the following
12  *     conditions are met:
13  *
14  *      - Redistributions of source code must retain the above
15  *        copyright notice, this list of conditions and the following
16  *        disclaimer.
17  *
18  *      - Redistributions in binary form must reproduce the above
19  *        copyright notice, this list of conditions and the following
20  *        disclaimer in the documentation and/or other materials
21  *        provided with the distribution.
22  *
23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30  * SOFTWARE.
31  *
32  */
33 #include <linux/kernel.h>
34 #include <linux/slab.h>
35 #include <net/sock.h>
36 #include <linux/in.h>
37 #include <linux/export.h>
38 #include <linux/time.h>
39 #include <linux/rds.h>
40 
41 #include "rds.h"
42 
rds_inc_init(struct rds_incoming * inc,struct rds_connection * conn,__be32 saddr)43 void rds_inc_init(struct rds_incoming *inc, struct rds_connection *conn,
44 		  __be32 saddr)
45 {
46 	atomic_set(&inc->i_refcount, 1);
47 	INIT_LIST_HEAD(&inc->i_item);
48 	inc->i_conn = conn;
49 	inc->i_saddr = saddr;
50 	inc->i_rdma_cookie = 0;
51 	inc->i_rx_tstamp.tv_sec = 0;
52 	inc->i_rx_tstamp.tv_usec = 0;
53 }
54 EXPORT_SYMBOL_GPL(rds_inc_init);
55 
rds_inc_path_init(struct rds_incoming * inc,struct rds_conn_path * cp,__be32 saddr)56 void rds_inc_path_init(struct rds_incoming *inc, struct rds_conn_path *cp,
57 		       __be32 saddr)
58 {
59 	atomic_set(&inc->i_refcount, 1);
60 	INIT_LIST_HEAD(&inc->i_item);
61 	inc->i_conn = cp->cp_conn;
62 	inc->i_conn_path = cp;
63 	inc->i_saddr = saddr;
64 	inc->i_rdma_cookie = 0;
65 	inc->i_rx_tstamp.tv_sec = 0;
66 	inc->i_rx_tstamp.tv_usec = 0;
67 }
68 EXPORT_SYMBOL_GPL(rds_inc_path_init);
69 
rds_inc_addref(struct rds_incoming * inc)70 static void rds_inc_addref(struct rds_incoming *inc)
71 {
72 	rdsdebug("addref inc %p ref %d\n", inc, atomic_read(&inc->i_refcount));
73 	atomic_inc(&inc->i_refcount);
74 }
75 
rds_inc_put(struct rds_incoming * inc)76 void rds_inc_put(struct rds_incoming *inc)
77 {
78 	rdsdebug("put inc %p ref %d\n", inc, atomic_read(&inc->i_refcount));
79 	if (atomic_dec_and_test(&inc->i_refcount)) {
80 		BUG_ON(!list_empty(&inc->i_item));
81 
82 		inc->i_conn->c_trans->inc_free(inc);
83 	}
84 }
85 EXPORT_SYMBOL_GPL(rds_inc_put);
86 
rds_recv_rcvbuf_delta(struct rds_sock * rs,struct sock * sk,struct rds_cong_map * map,int delta,__be16 port)87 static void rds_recv_rcvbuf_delta(struct rds_sock *rs, struct sock *sk,
88 				  struct rds_cong_map *map,
89 				  int delta, __be16 port)
90 {
91 	int now_congested;
92 
93 	if (delta == 0)
94 		return;
95 
96 	rs->rs_rcv_bytes += delta;
97 	now_congested = rs->rs_rcv_bytes > rds_sk_rcvbuf(rs);
98 
99 	rdsdebug("rs %p (%pI4:%u) recv bytes %d buf %d "
100 	  "now_cong %d delta %d\n",
101 	  rs, &rs->rs_bound_addr,
102 	  ntohs(rs->rs_bound_port), rs->rs_rcv_bytes,
103 	  rds_sk_rcvbuf(rs), now_congested, delta);
104 
105 	/* wasn't -> am congested */
106 	if (!rs->rs_congested && now_congested) {
107 		rs->rs_congested = 1;
108 		rds_cong_set_bit(map, port);
109 		rds_cong_queue_updates(map);
110 	}
111 	/* was -> aren't congested */
112 	/* Require more free space before reporting uncongested to prevent
113 	   bouncing cong/uncong state too often */
114 	else if (rs->rs_congested && (rs->rs_rcv_bytes < (rds_sk_rcvbuf(rs)/2))) {
115 		rs->rs_congested = 0;
116 		rds_cong_clear_bit(map, port);
117 		rds_cong_queue_updates(map);
118 	}
119 
120 	/* do nothing if no change in cong state */
121 }
122 
123 /*
124  * Process all extension headers that come with this message.
125  */
rds_recv_incoming_exthdrs(struct rds_incoming * inc,struct rds_sock * rs)126 static void rds_recv_incoming_exthdrs(struct rds_incoming *inc, struct rds_sock *rs)
127 {
128 	struct rds_header *hdr = &inc->i_hdr;
129 	unsigned int pos = 0, type, len;
130 	union {
131 		struct rds_ext_header_version version;
132 		struct rds_ext_header_rdma rdma;
133 		struct rds_ext_header_rdma_dest rdma_dest;
134 	} buffer;
135 
136 	while (1) {
137 		len = sizeof(buffer);
138 		type = rds_message_next_extension(hdr, &pos, &buffer, &len);
139 		if (type == RDS_EXTHDR_NONE)
140 			break;
141 		/* Process extension header here */
142 		switch (type) {
143 		case RDS_EXTHDR_RDMA:
144 			rds_rdma_unuse(rs, be32_to_cpu(buffer.rdma.h_rdma_rkey), 0);
145 			break;
146 
147 		case RDS_EXTHDR_RDMA_DEST:
148 			/* We ignore the size for now. We could stash it
149 			 * somewhere and use it for error checking. */
150 			inc->i_rdma_cookie = rds_rdma_make_cookie(
151 					be32_to_cpu(buffer.rdma_dest.h_rdma_rkey),
152 					be32_to_cpu(buffer.rdma_dest.h_rdma_offset));
153 
154 			break;
155 		}
156 	}
157 }
158 
rds_recv_hs_exthdrs(struct rds_header * hdr,struct rds_connection * conn)159 static void rds_recv_hs_exthdrs(struct rds_header *hdr,
160 				struct rds_connection *conn)
161 {
162 	unsigned int pos = 0, type, len;
163 	union {
164 		struct rds_ext_header_version version;
165 		u16 rds_npaths;
166 	} buffer;
167 
168 	while (1) {
169 		len = sizeof(buffer);
170 		type = rds_message_next_extension(hdr, &pos, &buffer, &len);
171 		if (type == RDS_EXTHDR_NONE)
172 			break;
173 		/* Process extension header here */
174 		switch (type) {
175 		case RDS_EXTHDR_NPATHS:
176 			conn->c_npaths = min_t(int, RDS_MPATH_WORKERS,
177 					       buffer.rds_npaths);
178 			break;
179 		default:
180 			pr_warn_ratelimited("ignoring unknown exthdr type "
181 					     "0x%x\n", type);
182 		}
183 	}
184 	/* if RDS_EXTHDR_NPATHS was not found, default to a single-path */
185 	conn->c_npaths = max_t(int, conn->c_npaths, 1);
186 }
187 
188 /* rds_start_mprds() will synchronously start multiple paths when appropriate.
189  * The scheme is based on the following rules:
190  *
191  * 1. rds_sendmsg on first connect attempt sends the probe ping, with the
192  *    sender's npaths (s_npaths)
193  * 2. rcvr of probe-ping knows the mprds_paths = min(s_npaths, r_npaths). It
194  *    sends back a probe-pong with r_npaths. After that, if rcvr is the
195  *    smaller ip addr, it starts rds_conn_path_connect_if_down on all
196  *    mprds_paths.
197  * 3. sender gets woken up, and can move to rds_conn_path_connect_if_down.
198  *    If it is the smaller ipaddr, rds_conn_path_connect_if_down can be
199  *    called after reception of the probe-pong on all mprds_paths.
200  *    Otherwise (sender of probe-ping is not the smaller ip addr): just call
201  *    rds_conn_path_connect_if_down on the hashed path. (see rule 4)
202  * 4. when cp_index > 0, rds_connect_worker must only trigger
203  *    a connection if laddr < faddr.
204  * 5. sender may end up queuing the packet on the cp. will get sent out later.
205  *    when connection is completed.
206  */
rds_start_mprds(struct rds_connection * conn)207 static void rds_start_mprds(struct rds_connection *conn)
208 {
209 	int i;
210 	struct rds_conn_path *cp;
211 
212 	if (conn->c_npaths > 1 && conn->c_laddr < conn->c_faddr) {
213 		for (i = 1; i < conn->c_npaths; i++) {
214 			cp = &conn->c_path[i];
215 			rds_conn_path_connect_if_down(cp);
216 		}
217 	}
218 }
219 
220 /*
221  * The transport must make sure that this is serialized against other
222  * rx and conn reset on this specific conn.
223  *
224  * We currently assert that only one fragmented message will be sent
225  * down a connection at a time.  This lets us reassemble in the conn
226  * instead of per-flow which means that we don't have to go digging through
227  * flows to tear down partial reassembly progress on conn failure and
228  * we save flow lookup and locking for each frag arrival.  It does mean
229  * that small messages will wait behind large ones.  Fragmenting at all
230  * is only to reduce the memory consumption of pre-posted buffers.
231  *
232  * The caller passes in saddr and daddr instead of us getting it from the
233  * conn.  This lets loopback, who only has one conn for both directions,
234  * tell us which roles the addrs in the conn are playing for this message.
235  */
rds_recv_incoming(struct rds_connection * conn,__be32 saddr,__be32 daddr,struct rds_incoming * inc,gfp_t gfp)236 void rds_recv_incoming(struct rds_connection *conn, __be32 saddr, __be32 daddr,
237 		       struct rds_incoming *inc, gfp_t gfp)
238 {
239 	struct rds_sock *rs = NULL;
240 	struct sock *sk;
241 	unsigned long flags;
242 	struct rds_conn_path *cp;
243 
244 	inc->i_conn = conn;
245 	inc->i_rx_jiffies = jiffies;
246 	if (conn->c_trans->t_mp_capable)
247 		cp = inc->i_conn_path;
248 	else
249 		cp = &conn->c_path[0];
250 
251 	rdsdebug("conn %p next %llu inc %p seq %llu len %u sport %u dport %u "
252 		 "flags 0x%x rx_jiffies %lu\n", conn,
253 		 (unsigned long long)cp->cp_next_rx_seq,
254 		 inc,
255 		 (unsigned long long)be64_to_cpu(inc->i_hdr.h_sequence),
256 		 be32_to_cpu(inc->i_hdr.h_len),
257 		 be16_to_cpu(inc->i_hdr.h_sport),
258 		 be16_to_cpu(inc->i_hdr.h_dport),
259 		 inc->i_hdr.h_flags,
260 		 inc->i_rx_jiffies);
261 
262 	/*
263 	 * Sequence numbers should only increase.  Messages get their
264 	 * sequence number as they're queued in a sending conn.  They
265 	 * can be dropped, though, if the sending socket is closed before
266 	 * they hit the wire.  So sequence numbers can skip forward
267 	 * under normal operation.  They can also drop back in the conn
268 	 * failover case as previously sent messages are resent down the
269 	 * new instance of a conn.  We drop those, otherwise we have
270 	 * to assume that the next valid seq does not come after a
271 	 * hole in the fragment stream.
272 	 *
273 	 * The headers don't give us a way to realize if fragments of
274 	 * a message have been dropped.  We assume that frags that arrive
275 	 * to a flow are part of the current message on the flow that is
276 	 * being reassembled.  This means that senders can't drop messages
277 	 * from the sending conn until all their frags are sent.
278 	 *
279 	 * XXX we could spend more on the wire to get more robust failure
280 	 * detection, arguably worth it to avoid data corruption.
281 	 */
282 	if (be64_to_cpu(inc->i_hdr.h_sequence) < cp->cp_next_rx_seq &&
283 	    (inc->i_hdr.h_flags & RDS_FLAG_RETRANSMITTED)) {
284 		rds_stats_inc(s_recv_drop_old_seq);
285 		goto out;
286 	}
287 	cp->cp_next_rx_seq = be64_to_cpu(inc->i_hdr.h_sequence) + 1;
288 
289 	if (rds_sysctl_ping_enable && inc->i_hdr.h_dport == 0) {
290 		if (inc->i_hdr.h_sport == 0) {
291 			rdsdebug("ignore ping with 0 sport from 0x%x\n", saddr);
292 			goto out;
293 		}
294 		rds_stats_inc(s_recv_ping);
295 		rds_send_pong(cp, inc->i_hdr.h_sport);
296 		/* if this is a handshake ping, start multipath if necessary */
297 		if (RDS_HS_PROBE(inc->i_hdr.h_sport, inc->i_hdr.h_dport)) {
298 			rds_recv_hs_exthdrs(&inc->i_hdr, cp->cp_conn);
299 			rds_start_mprds(cp->cp_conn);
300 		}
301 		goto out;
302 	}
303 
304 	if (inc->i_hdr.h_dport ==  RDS_FLAG_PROBE_PORT &&
305 	    inc->i_hdr.h_sport == 0) {
306 		rds_recv_hs_exthdrs(&inc->i_hdr, cp->cp_conn);
307 		/* if this is a handshake pong, start multipath if necessary */
308 		rds_start_mprds(cp->cp_conn);
309 		wake_up(&cp->cp_conn->c_hs_waitq);
310 		goto out;
311 	}
312 
313 	rs = rds_find_bound(daddr, inc->i_hdr.h_dport);
314 	if (!rs) {
315 		rds_stats_inc(s_recv_drop_no_sock);
316 		goto out;
317 	}
318 
319 	/* Process extension headers */
320 	rds_recv_incoming_exthdrs(inc, rs);
321 
322 	/* We can be racing with rds_release() which marks the socket dead. */
323 	sk = rds_rs_to_sk(rs);
324 
325 	/* serialize with rds_release -> sock_orphan */
326 	write_lock_irqsave(&rs->rs_recv_lock, flags);
327 	if (!sock_flag(sk, SOCK_DEAD)) {
328 		rdsdebug("adding inc %p to rs %p's recv queue\n", inc, rs);
329 		rds_stats_inc(s_recv_queued);
330 		rds_recv_rcvbuf_delta(rs, sk, inc->i_conn->c_lcong,
331 				      be32_to_cpu(inc->i_hdr.h_len),
332 				      inc->i_hdr.h_dport);
333 		if (sock_flag(sk, SOCK_RCVTSTAMP))
334 			do_gettimeofday(&inc->i_rx_tstamp);
335 		rds_inc_addref(inc);
336 		list_add_tail(&inc->i_item, &rs->rs_recv_queue);
337 		__rds_wake_sk_sleep(sk);
338 	} else {
339 		rds_stats_inc(s_recv_drop_dead_sock);
340 	}
341 	write_unlock_irqrestore(&rs->rs_recv_lock, flags);
342 
343 out:
344 	if (rs)
345 		rds_sock_put(rs);
346 }
347 EXPORT_SYMBOL_GPL(rds_recv_incoming);
348 
349 /*
350  * be very careful here.  This is being called as the condition in
351  * wait_event_*() needs to cope with being called many times.
352  */
rds_next_incoming(struct rds_sock * rs,struct rds_incoming ** inc)353 static int rds_next_incoming(struct rds_sock *rs, struct rds_incoming **inc)
354 {
355 	unsigned long flags;
356 
357 	if (!*inc) {
358 		read_lock_irqsave(&rs->rs_recv_lock, flags);
359 		if (!list_empty(&rs->rs_recv_queue)) {
360 			*inc = list_entry(rs->rs_recv_queue.next,
361 					  struct rds_incoming,
362 					  i_item);
363 			rds_inc_addref(*inc);
364 		}
365 		read_unlock_irqrestore(&rs->rs_recv_lock, flags);
366 	}
367 
368 	return *inc != NULL;
369 }
370 
rds_still_queued(struct rds_sock * rs,struct rds_incoming * inc,int drop)371 static int rds_still_queued(struct rds_sock *rs, struct rds_incoming *inc,
372 			    int drop)
373 {
374 	struct sock *sk = rds_rs_to_sk(rs);
375 	int ret = 0;
376 	unsigned long flags;
377 
378 	write_lock_irqsave(&rs->rs_recv_lock, flags);
379 	if (!list_empty(&inc->i_item)) {
380 		ret = 1;
381 		if (drop) {
382 			/* XXX make sure this i_conn is reliable */
383 			rds_recv_rcvbuf_delta(rs, sk, inc->i_conn->c_lcong,
384 					      -be32_to_cpu(inc->i_hdr.h_len),
385 					      inc->i_hdr.h_dport);
386 			list_del_init(&inc->i_item);
387 			rds_inc_put(inc);
388 		}
389 	}
390 	write_unlock_irqrestore(&rs->rs_recv_lock, flags);
391 
392 	rdsdebug("inc %p rs %p still %d dropped %d\n", inc, rs, ret, drop);
393 	return ret;
394 }
395 
396 /*
397  * Pull errors off the error queue.
398  * If msghdr is NULL, we will just purge the error queue.
399  */
rds_notify_queue_get(struct rds_sock * rs,struct msghdr * msghdr)400 int rds_notify_queue_get(struct rds_sock *rs, struct msghdr *msghdr)
401 {
402 	struct rds_notifier *notifier;
403 	struct rds_rdma_notify cmsg = { 0 }; /* fill holes with zero */
404 	unsigned int count = 0, max_messages = ~0U;
405 	unsigned long flags;
406 	LIST_HEAD(copy);
407 	int err = 0;
408 
409 
410 	/* put_cmsg copies to user space and thus may sleep. We can't do this
411 	 * with rs_lock held, so first grab as many notifications as we can stuff
412 	 * in the user provided cmsg buffer. We don't try to copy more, to avoid
413 	 * losing notifications - except when the buffer is so small that it wouldn't
414 	 * even hold a single notification. Then we give him as much of this single
415 	 * msg as we can squeeze in, and set MSG_CTRUNC.
416 	 */
417 	if (msghdr) {
418 		max_messages = msghdr->msg_controllen / CMSG_SPACE(sizeof(cmsg));
419 		if (!max_messages)
420 			max_messages = 1;
421 	}
422 
423 	spin_lock_irqsave(&rs->rs_lock, flags);
424 	while (!list_empty(&rs->rs_notify_queue) && count < max_messages) {
425 		notifier = list_entry(rs->rs_notify_queue.next,
426 				struct rds_notifier, n_list);
427 		list_move(&notifier->n_list, &copy);
428 		count++;
429 	}
430 	spin_unlock_irqrestore(&rs->rs_lock, flags);
431 
432 	if (!count)
433 		return 0;
434 
435 	while (!list_empty(&copy)) {
436 		notifier = list_entry(copy.next, struct rds_notifier, n_list);
437 
438 		if (msghdr) {
439 			cmsg.user_token = notifier->n_user_token;
440 			cmsg.status = notifier->n_status;
441 
442 			err = put_cmsg(msghdr, SOL_RDS, RDS_CMSG_RDMA_STATUS,
443 				       sizeof(cmsg), &cmsg);
444 			if (err)
445 				break;
446 		}
447 
448 		list_del_init(&notifier->n_list);
449 		kfree(notifier);
450 	}
451 
452 	/* If we bailed out because of an error in put_cmsg,
453 	 * we may be left with one or more notifications that we
454 	 * didn't process. Return them to the head of the list. */
455 	if (!list_empty(&copy)) {
456 		spin_lock_irqsave(&rs->rs_lock, flags);
457 		list_splice(&copy, &rs->rs_notify_queue);
458 		spin_unlock_irqrestore(&rs->rs_lock, flags);
459 	}
460 
461 	return err;
462 }
463 
464 /*
465  * Queue a congestion notification
466  */
rds_notify_cong(struct rds_sock * rs,struct msghdr * msghdr)467 static int rds_notify_cong(struct rds_sock *rs, struct msghdr *msghdr)
468 {
469 	uint64_t notify = rs->rs_cong_notify;
470 	unsigned long flags;
471 	int err;
472 
473 	err = put_cmsg(msghdr, SOL_RDS, RDS_CMSG_CONG_UPDATE,
474 			sizeof(notify), &notify);
475 	if (err)
476 		return err;
477 
478 	spin_lock_irqsave(&rs->rs_lock, flags);
479 	rs->rs_cong_notify &= ~notify;
480 	spin_unlock_irqrestore(&rs->rs_lock, flags);
481 
482 	return 0;
483 }
484 
485 /*
486  * Receive any control messages.
487  */
rds_cmsg_recv(struct rds_incoming * inc,struct msghdr * msg,struct rds_sock * rs)488 static int rds_cmsg_recv(struct rds_incoming *inc, struct msghdr *msg,
489 			 struct rds_sock *rs)
490 {
491 	int ret = 0;
492 
493 	if (inc->i_rdma_cookie) {
494 		ret = put_cmsg(msg, SOL_RDS, RDS_CMSG_RDMA_DEST,
495 				sizeof(inc->i_rdma_cookie), &inc->i_rdma_cookie);
496 		if (ret)
497 			return ret;
498 	}
499 
500 	if ((inc->i_rx_tstamp.tv_sec != 0) &&
501 	    sock_flag(rds_rs_to_sk(rs), SOCK_RCVTSTAMP)) {
502 		ret = put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMP,
503 			       sizeof(struct timeval),
504 			       &inc->i_rx_tstamp);
505 		if (ret)
506 			return ret;
507 	}
508 
509 	return 0;
510 }
511 
rds_recvmsg(struct socket * sock,struct msghdr * msg,size_t size,int msg_flags)512 int rds_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
513 		int msg_flags)
514 {
515 	struct sock *sk = sock->sk;
516 	struct rds_sock *rs = rds_sk_to_rs(sk);
517 	long timeo;
518 	int ret = 0, nonblock = msg_flags & MSG_DONTWAIT;
519 	DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
520 	struct rds_incoming *inc = NULL;
521 
522 	/* udp_recvmsg()->sock_recvtimeo() gets away without locking too.. */
523 	timeo = sock_rcvtimeo(sk, nonblock);
524 
525 	rdsdebug("size %zu flags 0x%x timeo %ld\n", size, msg_flags, timeo);
526 
527 	if (msg_flags & MSG_OOB)
528 		goto out;
529 
530 	while (1) {
531 		struct iov_iter save;
532 		/* If there are pending notifications, do those - and nothing else */
533 		if (!list_empty(&rs->rs_notify_queue)) {
534 			ret = rds_notify_queue_get(rs, msg);
535 			break;
536 		}
537 
538 		if (rs->rs_cong_notify) {
539 			ret = rds_notify_cong(rs, msg);
540 			break;
541 		}
542 
543 		if (!rds_next_incoming(rs, &inc)) {
544 			if (nonblock) {
545 				ret = -EAGAIN;
546 				break;
547 			}
548 
549 			timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
550 					(!list_empty(&rs->rs_notify_queue) ||
551 					 rs->rs_cong_notify ||
552 					 rds_next_incoming(rs, &inc)), timeo);
553 			rdsdebug("recvmsg woke inc %p timeo %ld\n", inc,
554 				 timeo);
555 			if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
556 				continue;
557 
558 			ret = timeo;
559 			if (ret == 0)
560 				ret = -ETIMEDOUT;
561 			break;
562 		}
563 
564 		rdsdebug("copying inc %p from %pI4:%u to user\n", inc,
565 			 &inc->i_conn->c_faddr,
566 			 ntohs(inc->i_hdr.h_sport));
567 		save = msg->msg_iter;
568 		ret = inc->i_conn->c_trans->inc_copy_to_user(inc, &msg->msg_iter);
569 		if (ret < 0)
570 			break;
571 
572 		/*
573 		 * if the message we just copied isn't at the head of the
574 		 * recv queue then someone else raced us to return it, try
575 		 * to get the next message.
576 		 */
577 		if (!rds_still_queued(rs, inc, !(msg_flags & MSG_PEEK))) {
578 			rds_inc_put(inc);
579 			inc = NULL;
580 			rds_stats_inc(s_recv_deliver_raced);
581 			msg->msg_iter = save;
582 			continue;
583 		}
584 
585 		if (ret < be32_to_cpu(inc->i_hdr.h_len)) {
586 			if (msg_flags & MSG_TRUNC)
587 				ret = be32_to_cpu(inc->i_hdr.h_len);
588 			msg->msg_flags |= MSG_TRUNC;
589 		}
590 
591 		if (rds_cmsg_recv(inc, msg, rs)) {
592 			ret = -EFAULT;
593 			goto out;
594 		}
595 
596 		rds_stats_inc(s_recv_delivered);
597 
598 		if (sin) {
599 			sin->sin_family = AF_INET;
600 			sin->sin_port = inc->i_hdr.h_sport;
601 			sin->sin_addr.s_addr = inc->i_saddr;
602 			memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
603 			msg->msg_namelen = sizeof(*sin);
604 		}
605 		break;
606 	}
607 
608 	if (inc)
609 		rds_inc_put(inc);
610 
611 out:
612 	return ret;
613 }
614 
615 /*
616  * The socket is being shut down and we're asked to drop messages that were
617  * queued for recvmsg.  The caller has unbound the socket so the receive path
618  * won't queue any more incoming fragments or messages on the socket.
619  */
rds_clear_recv_queue(struct rds_sock * rs)620 void rds_clear_recv_queue(struct rds_sock *rs)
621 {
622 	struct sock *sk = rds_rs_to_sk(rs);
623 	struct rds_incoming *inc, *tmp;
624 	unsigned long flags;
625 
626 	write_lock_irqsave(&rs->rs_recv_lock, flags);
627 	list_for_each_entry_safe(inc, tmp, &rs->rs_recv_queue, i_item) {
628 		rds_recv_rcvbuf_delta(rs, sk, inc->i_conn->c_lcong,
629 				      -be32_to_cpu(inc->i_hdr.h_len),
630 				      inc->i_hdr.h_dport);
631 		list_del_init(&inc->i_item);
632 		rds_inc_put(inc);
633 	}
634 	write_unlock_irqrestore(&rs->rs_recv_lock, flags);
635 }
636 
637 /*
638  * inc->i_saddr isn't used here because it is only set in the receive
639  * path.
640  */
rds_inc_info_copy(struct rds_incoming * inc,struct rds_info_iterator * iter,__be32 saddr,__be32 daddr,int flip)641 void rds_inc_info_copy(struct rds_incoming *inc,
642 		       struct rds_info_iterator *iter,
643 		       __be32 saddr, __be32 daddr, int flip)
644 {
645 	struct rds_info_message minfo;
646 
647 	minfo.seq = be64_to_cpu(inc->i_hdr.h_sequence);
648 	minfo.len = be32_to_cpu(inc->i_hdr.h_len);
649 
650 	if (flip) {
651 		minfo.laddr = daddr;
652 		minfo.faddr = saddr;
653 		minfo.lport = inc->i_hdr.h_dport;
654 		minfo.fport = inc->i_hdr.h_sport;
655 	} else {
656 		minfo.laddr = saddr;
657 		minfo.faddr = daddr;
658 		minfo.lport = inc->i_hdr.h_sport;
659 		minfo.fport = inc->i_hdr.h_dport;
660 	}
661 
662 	minfo.flags = 0;
663 
664 	rds_info_copy(iter, &minfo, sizeof(minfo));
665 }
666