blob: 104fe033203da51eeef849782e1c291e072cdde6 [file] [log] [blame]
Andy Grover5c115592009-02-24 15:30:27 +00001/*
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 <net/sock.h>
35#include <linux/in.h>
36#include <linux/list.h>
37
38#include "rds.h"
39#include "rdma.h"
40
41/* When transmitting messages in rds_send_xmit, we need to emerge from
42 * time to time and briefly release the CPU. Otherwise the softlock watchdog
43 * will kick our shin.
44 * Also, it seems fairer to not let one busy connection stall all the
45 * others.
46 *
47 * send_batch_count is the number of times we'll loop in send_xmit. Setting
48 * it to 0 will restore the old behavior (where we looped until we had
49 * drained the queue).
50 */
51static int send_batch_count = 64;
52module_param(send_batch_count, int, 0444);
53MODULE_PARM_DESC(send_batch_count, " batch factor when working the send queue");
54
55/*
56 * Reset the send state. Caller must hold c_send_lock when calling here.
57 */
58void rds_send_reset(struct rds_connection *conn)
59{
60 struct rds_message *rm, *tmp;
61 unsigned long flags;
62
63 if (conn->c_xmit_rm) {
64 /* Tell the user the RDMA op is no longer mapped by the
65 * transport. This isn't entirely true (it's flushed out
66 * independently) but as the connection is down, there's
67 * no ongoing RDMA to/from that memory */
68 rds_message_unmapped(conn->c_xmit_rm);
69 rds_message_put(conn->c_xmit_rm);
70 conn->c_xmit_rm = NULL;
71 }
72 conn->c_xmit_sg = 0;
73 conn->c_xmit_hdr_off = 0;
74 conn->c_xmit_data_off = 0;
75 conn->c_xmit_rdma_sent = 0;
76
77 conn->c_map_queued = 0;
78
79 conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
80 conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
81
82 /* Mark messages as retransmissions, and move them to the send q */
83 spin_lock_irqsave(&conn->c_lock, flags);
84 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
85 set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
86 set_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags);
87 }
88 list_splice_init(&conn->c_retrans, &conn->c_send_queue);
89 spin_unlock_irqrestore(&conn->c_lock, flags);
90}
91
92/*
93 * We're making the concious trade-off here to only send one message
94 * down the connection at a time.
95 * Pro:
96 * - tx queueing is a simple fifo list
97 * - reassembly is optional and easily done by transports per conn
98 * - no per flow rx lookup at all, straight to the socket
99 * - less per-frag memory and wire overhead
100 * Con:
101 * - queued acks can be delayed behind large messages
102 * Depends:
103 * - small message latency is higher behind queued large messages
104 * - large message latency isn't starved by intervening small sends
105 */
106int rds_send_xmit(struct rds_connection *conn)
107{
108 struct rds_message *rm;
109 unsigned long flags;
110 unsigned int tmp;
111 unsigned int send_quota = send_batch_count;
112 struct scatterlist *sg;
113 int ret = 0;
114 int was_empty = 0;
115 LIST_HEAD(to_be_dropped);
116
117 /*
118 * sendmsg calls here after having queued its message on the send
119 * queue. We only have one task feeding the connection at a time. If
120 * another thread is already feeding the queue then we back off. This
121 * avoids blocking the caller and trading per-connection data between
122 * caches per message.
123 *
124 * The sem holder will issue a retry if they notice that someone queued
125 * a message after they stopped walking the send queue but before they
126 * dropped the sem.
127 */
128 if (!mutex_trylock(&conn->c_send_lock)) {
129 rds_stats_inc(s_send_sem_contention);
130 ret = -ENOMEM;
131 goto out;
132 }
133
134 if (conn->c_trans->xmit_prepare)
135 conn->c_trans->xmit_prepare(conn);
136
137 /*
138 * spin trying to push headers and data down the connection until
139 * the connection doens't make forward progress.
140 */
141 while (--send_quota) {
142 /*
143 * See if need to send a congestion map update if we're
144 * between sending messages. The send_sem protects our sole
145 * use of c_map_offset and _bytes.
146 * Note this is used only by transports that define a special
147 * xmit_cong_map function. For all others, we create allocate
148 * a cong_map message and treat it just like any other send.
149 */
150 if (conn->c_map_bytes) {
151 ret = conn->c_trans->xmit_cong_map(conn, conn->c_lcong,
152 conn->c_map_offset);
153 if (ret <= 0)
154 break;
155
156 conn->c_map_offset += ret;
157 conn->c_map_bytes -= ret;
158 if (conn->c_map_bytes)
159 continue;
160 }
161
162 /* If we're done sending the current message, clear the
163 * offset and S/G temporaries.
164 */
165 rm = conn->c_xmit_rm;
166 if (rm != NULL &&
167 conn->c_xmit_hdr_off == sizeof(struct rds_header) &&
168 conn->c_xmit_sg == rm->m_nents) {
169 conn->c_xmit_rm = NULL;
170 conn->c_xmit_sg = 0;
171 conn->c_xmit_hdr_off = 0;
172 conn->c_xmit_data_off = 0;
173 conn->c_xmit_rdma_sent = 0;
174
175 /* Release the reference to the previous message. */
176 rds_message_put(rm);
177 rm = NULL;
178 }
179
180 /* If we're asked to send a cong map update, do so.
181 */
182 if (rm == NULL && test_and_clear_bit(0, &conn->c_map_queued)) {
183 if (conn->c_trans->xmit_cong_map != NULL) {
184 conn->c_map_offset = 0;
185 conn->c_map_bytes = sizeof(struct rds_header) +
186 RDS_CONG_MAP_BYTES;
187 continue;
188 }
189
190 rm = rds_cong_update_alloc(conn);
191 if (IS_ERR(rm)) {
192 ret = PTR_ERR(rm);
193 break;
194 }
195
196 conn->c_xmit_rm = rm;
197 }
198
199 /*
200 * Grab the next message from the send queue, if there is one.
201 *
202 * c_xmit_rm holds a ref while we're sending this message down
203 * the connction. We can use this ref while holding the
204 * send_sem.. rds_send_reset() is serialized with it.
205 */
206 if (rm == NULL) {
207 unsigned int len;
208
209 spin_lock_irqsave(&conn->c_lock, flags);
210
211 if (!list_empty(&conn->c_send_queue)) {
212 rm = list_entry(conn->c_send_queue.next,
213 struct rds_message,
214 m_conn_item);
215 rds_message_addref(rm);
216
217 /*
218 * Move the message from the send queue to the retransmit
219 * list right away.
220 */
221 list_move_tail(&rm->m_conn_item, &conn->c_retrans);
222 }
223
224 spin_unlock_irqrestore(&conn->c_lock, flags);
225
226 if (rm == NULL) {
227 was_empty = 1;
228 break;
229 }
230
231 /* Unfortunately, the way Infiniband deals with
232 * RDMA to a bad MR key is by moving the entire
233 * queue pair to error state. We cold possibly
234 * recover from that, but right now we drop the
235 * connection.
236 * Therefore, we never retransmit messages with RDMA ops.
237 */
238 if (rm->m_rdma_op
239 && test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) {
240 spin_lock_irqsave(&conn->c_lock, flags);
241 if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags))
242 list_move(&rm->m_conn_item, &to_be_dropped);
243 spin_unlock_irqrestore(&conn->c_lock, flags);
244 rds_message_put(rm);
245 continue;
246 }
247
248 /* Require an ACK every once in a while */
249 len = ntohl(rm->m_inc.i_hdr.h_len);
250 if (conn->c_unacked_packets == 0
251 || conn->c_unacked_bytes < len) {
252 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
253
254 conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
255 conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
256 rds_stats_inc(s_send_ack_required);
257 } else {
258 conn->c_unacked_bytes -= len;
259 conn->c_unacked_packets--;
260 }
261
262 conn->c_xmit_rm = rm;
263 }
264
265 /*
266 * Try and send an rdma message. Let's see if we can
267 * keep this simple and require that the transport either
268 * send the whole rdma or none of it.
269 */
270 if (rm->m_rdma_op && !conn->c_xmit_rdma_sent) {
271 ret = conn->c_trans->xmit_rdma(conn, rm->m_rdma_op);
272 if (ret)
273 break;
274 conn->c_xmit_rdma_sent = 1;
275 /* The transport owns the mapped memory for now.
276 * You can't unmap it while it's on the send queue */
277 set_bit(RDS_MSG_MAPPED, &rm->m_flags);
278 }
279
280 if (conn->c_xmit_hdr_off < sizeof(struct rds_header) ||
281 conn->c_xmit_sg < rm->m_nents) {
282 ret = conn->c_trans->xmit(conn, rm,
283 conn->c_xmit_hdr_off,
284 conn->c_xmit_sg,
285 conn->c_xmit_data_off);
286 if (ret <= 0)
287 break;
288
289 if (conn->c_xmit_hdr_off < sizeof(struct rds_header)) {
290 tmp = min_t(int, ret,
291 sizeof(struct rds_header) -
292 conn->c_xmit_hdr_off);
293 conn->c_xmit_hdr_off += tmp;
294 ret -= tmp;
295 }
296
297 sg = &rm->m_sg[conn->c_xmit_sg];
298 while (ret) {
299 tmp = min_t(int, ret, sg->length -
300 conn->c_xmit_data_off);
301 conn->c_xmit_data_off += tmp;
302 ret -= tmp;
303 if (conn->c_xmit_data_off == sg->length) {
304 conn->c_xmit_data_off = 0;
305 sg++;
306 conn->c_xmit_sg++;
307 BUG_ON(ret != 0 &&
308 conn->c_xmit_sg == rm->m_nents);
309 }
310 }
311 }
312 }
313
314 /* Nuke any messages we decided not to retransmit. */
315 if (!list_empty(&to_be_dropped))
316 rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED);
317
318 if (conn->c_trans->xmit_complete)
319 conn->c_trans->xmit_complete(conn);
320
321 /*
322 * We might be racing with another sender who queued a message but
323 * backed off on noticing that we held the c_send_lock. If we check
324 * for queued messages after dropping the sem then either we'll
325 * see the queued message or the queuer will get the sem. If we
326 * notice the queued message then we trigger an immediate retry.
327 *
328 * We need to be careful only to do this when we stopped processing
329 * the send queue because it was empty. It's the only way we
330 * stop processing the loop when the transport hasn't taken
331 * responsibility for forward progress.
332 */
333 mutex_unlock(&conn->c_send_lock);
334
335 if (conn->c_map_bytes || (send_quota == 0 && !was_empty)) {
336 /* We exhausted the send quota, but there's work left to
337 * do. Return and (re-)schedule the send worker.
338 */
339 ret = -EAGAIN;
340 }
341
342 if (ret == 0 && was_empty) {
343 /* A simple bit test would be way faster than taking the
344 * spin lock */
345 spin_lock_irqsave(&conn->c_lock, flags);
346 if (!list_empty(&conn->c_send_queue)) {
347 rds_stats_inc(s_send_sem_queue_raced);
348 ret = -EAGAIN;
349 }
350 spin_unlock_irqrestore(&conn->c_lock, flags);
351 }
352out:
353 return ret;
354}
355
356static void rds_send_sndbuf_remove(struct rds_sock *rs, struct rds_message *rm)
357{
358 u32 len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
359
360 assert_spin_locked(&rs->rs_lock);
361
362 BUG_ON(rs->rs_snd_bytes < len);
363 rs->rs_snd_bytes -= len;
364
365 if (rs->rs_snd_bytes == 0)
366 rds_stats_inc(s_send_queue_empty);
367}
368
369static inline int rds_send_is_acked(struct rds_message *rm, u64 ack,
370 is_acked_func is_acked)
371{
372 if (is_acked)
373 return is_acked(rm, ack);
374 return be64_to_cpu(rm->m_inc.i_hdr.h_sequence) <= ack;
375}
376
377/*
378 * Returns true if there are no messages on the send and retransmit queues
379 * which have a sequence number greater than or equal to the given sequence
380 * number.
381 */
382int rds_send_acked_before(struct rds_connection *conn, u64 seq)
383{
384 struct rds_message *rm, *tmp;
385 int ret = 1;
386
387 spin_lock(&conn->c_lock);
388
389 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
390 if (be64_to_cpu(rm->m_inc.i_hdr.h_sequence) < seq)
391 ret = 0;
392 break;
393 }
394
395 list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
396 if (be64_to_cpu(rm->m_inc.i_hdr.h_sequence) < seq)
397 ret = 0;
398 break;
399 }
400
401 spin_unlock(&conn->c_lock);
402
403 return ret;
404}
405
406/*
407 * This is pretty similar to what happens below in the ACK
408 * handling code - except that we call here as soon as we get
409 * the IB send completion on the RDMA op and the accompanying
410 * message.
411 */
412void rds_rdma_send_complete(struct rds_message *rm, int status)
413{
414 struct rds_sock *rs = NULL;
415 struct rds_rdma_op *ro;
416 struct rds_notifier *notifier;
417
418 spin_lock(&rm->m_rs_lock);
419
420 ro = rm->m_rdma_op;
421 if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags)
422 && ro && ro->r_notify && ro->r_notifier) {
423 notifier = ro->r_notifier;
424 rs = rm->m_rs;
425 sock_hold(rds_rs_to_sk(rs));
426
427 notifier->n_status = status;
428 spin_lock(&rs->rs_lock);
429 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
430 spin_unlock(&rs->rs_lock);
431
432 ro->r_notifier = NULL;
433 }
434
435 spin_unlock(&rm->m_rs_lock);
436
437 if (rs) {
438 rds_wake_sk_sleep(rs);
439 sock_put(rds_rs_to_sk(rs));
440 }
441}
442
443/*
444 * This is the same as rds_rdma_send_complete except we
445 * don't do any locking - we have all the ingredients (message,
446 * socket, socket lock) and can just move the notifier.
447 */
448static inline void
449__rds_rdma_send_complete(struct rds_sock *rs, struct rds_message *rm, int status)
450{
451 struct rds_rdma_op *ro;
452
453 ro = rm->m_rdma_op;
454 if (ro && ro->r_notify && ro->r_notifier) {
455 ro->r_notifier->n_status = status;
456 list_add_tail(&ro->r_notifier->n_list, &rs->rs_notify_queue);
457 ro->r_notifier = NULL;
458 }
459
460 /* No need to wake the app - caller does this */
461}
462
463/*
464 * This is called from the IB send completion when we detect
465 * a RDMA operation that failed with remote access error.
466 * So speed is not an issue here.
467 */
468struct rds_message *rds_send_get_message(struct rds_connection *conn,
469 struct rds_rdma_op *op)
470{
471 struct rds_message *rm, *tmp, *found = NULL;
472 unsigned long flags;
473
474 spin_lock_irqsave(&conn->c_lock, flags);
475
476 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
477 if (rm->m_rdma_op == op) {
478 atomic_inc(&rm->m_refcount);
479 found = rm;
480 goto out;
481 }
482 }
483
484 list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
485 if (rm->m_rdma_op == op) {
486 atomic_inc(&rm->m_refcount);
487 found = rm;
488 break;
489 }
490 }
491
492out:
493 spin_unlock_irqrestore(&conn->c_lock, flags);
494
495 return found;
496}
497
498/*
499 * This removes messages from the socket's list if they're on it. The list
500 * argument must be private to the caller, we must be able to modify it
501 * without locks. The messages must have a reference held for their
502 * position on the list. This function will drop that reference after
503 * removing the messages from the 'messages' list regardless of if it found
504 * the messages on the socket list or not.
505 */
506void rds_send_remove_from_sock(struct list_head *messages, int status)
507{
508 unsigned long flags = 0; /* silence gcc :P */
509 struct rds_sock *rs = NULL;
510 struct rds_message *rm;
511
512 local_irq_save(flags);
513 while (!list_empty(messages)) {
514 rm = list_entry(messages->next, struct rds_message,
515 m_conn_item);
516 list_del_init(&rm->m_conn_item);
517
518 /*
519 * If we see this flag cleared then we're *sure* that someone
520 * else beat us to removing it from the sock. If we race
521 * with their flag update we'll get the lock and then really
522 * see that the flag has been cleared.
523 *
524 * The message spinlock makes sure nobody clears rm->m_rs
525 * while we're messing with it. It does not prevent the
526 * message from being removed from the socket, though.
527 */
528 spin_lock(&rm->m_rs_lock);
529 if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags))
530 goto unlock_and_drop;
531
532 if (rs != rm->m_rs) {
533 if (rs) {
534 spin_unlock(&rs->rs_lock);
535 rds_wake_sk_sleep(rs);
536 sock_put(rds_rs_to_sk(rs));
537 }
538 rs = rm->m_rs;
539 spin_lock(&rs->rs_lock);
540 sock_hold(rds_rs_to_sk(rs));
541 }
542
543 if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) {
544 struct rds_rdma_op *ro = rm->m_rdma_op;
545 struct rds_notifier *notifier;
546
547 list_del_init(&rm->m_sock_item);
548 rds_send_sndbuf_remove(rs, rm);
549
550 if (ro && ro->r_notifier
551 && (status || ro->r_notify)) {
552 notifier = ro->r_notifier;
553 list_add_tail(&notifier->n_list,
554 &rs->rs_notify_queue);
555 if (!notifier->n_status)
556 notifier->n_status = status;
557 rm->m_rdma_op->r_notifier = NULL;
558 }
559 rds_message_put(rm);
560 rm->m_rs = NULL;
561 }
562
563unlock_and_drop:
564 spin_unlock(&rm->m_rs_lock);
565 rds_message_put(rm);
566 }
567
568 if (rs) {
569 spin_unlock(&rs->rs_lock);
570 rds_wake_sk_sleep(rs);
571 sock_put(rds_rs_to_sk(rs));
572 }
573 local_irq_restore(flags);
574}
575
576/*
577 * Transports call here when they've determined that the receiver queued
578 * messages up to, and including, the given sequence number. Messages are
579 * moved to the retrans queue when rds_send_xmit picks them off the send
580 * queue. This means that in the TCP case, the message may not have been
581 * assigned the m_ack_seq yet - but that's fine as long as tcp_is_acked
582 * checks the RDS_MSG_HAS_ACK_SEQ bit.
583 *
584 * XXX It's not clear to me how this is safely serialized with socket
585 * destruction. Maybe it should bail if it sees SOCK_DEAD.
586 */
587void rds_send_drop_acked(struct rds_connection *conn, u64 ack,
588 is_acked_func is_acked)
589{
590 struct rds_message *rm, *tmp;
591 unsigned long flags;
592 LIST_HEAD(list);
593
594 spin_lock_irqsave(&conn->c_lock, flags);
595
596 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
597 if (!rds_send_is_acked(rm, ack, is_acked))
598 break;
599
600 list_move(&rm->m_conn_item, &list);
601 clear_bit(RDS_MSG_ON_CONN, &rm->m_flags);
602 }
603
604 /* order flag updates with spin locks */
605 if (!list_empty(&list))
606 smp_mb__after_clear_bit();
607
608 spin_unlock_irqrestore(&conn->c_lock, flags);
609
610 /* now remove the messages from the sock list as needed */
611 rds_send_remove_from_sock(&list, RDS_RDMA_SUCCESS);
612}
613
614void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest)
615{
616 struct rds_message *rm, *tmp;
617 struct rds_connection *conn;
Andy Groverf1cffcb2009-04-01 08:20:18 +0000618 unsigned long flags, flags2;
Andy Grover5c115592009-02-24 15:30:27 +0000619 LIST_HEAD(list);
620 int wake = 0;
621
622 /* get all the messages we're dropping under the rs lock */
623 spin_lock_irqsave(&rs->rs_lock, flags);
624
625 list_for_each_entry_safe(rm, tmp, &rs->rs_send_queue, m_sock_item) {
626 if (dest && (dest->sin_addr.s_addr != rm->m_daddr ||
627 dest->sin_port != rm->m_inc.i_hdr.h_dport))
628 continue;
629
630 wake = 1;
631 list_move(&rm->m_sock_item, &list);
632 rds_send_sndbuf_remove(rs, rm);
633 clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
634
635 /* If this is a RDMA operation, notify the app. */
636 __rds_rdma_send_complete(rs, rm, RDS_RDMA_CANCELED);
637 }
638
639 /* order flag updates with the rs lock */
640 if (wake)
641 smp_mb__after_clear_bit();
642
643 spin_unlock_irqrestore(&rs->rs_lock, flags);
644
645 if (wake)
646 rds_wake_sk_sleep(rs);
647
648 conn = NULL;
649
650 /* now remove the messages from the conn list as needed */
651 list_for_each_entry(rm, &list, m_sock_item) {
652 /* We do this here rather than in the loop above, so that
653 * we don't have to nest m_rs_lock under rs->rs_lock */
Andy Groverf1cffcb2009-04-01 08:20:18 +0000654 spin_lock_irqsave(&rm->m_rs_lock, flags2);
Andy Grover5c115592009-02-24 15:30:27 +0000655 rm->m_rs = NULL;
Andy Groverf1cffcb2009-04-01 08:20:18 +0000656 spin_unlock_irqrestore(&rm->m_rs_lock, flags2);
Andy Grover5c115592009-02-24 15:30:27 +0000657
658 /*
659 * If we see this flag cleared then we're *sure* that someone
660 * else beat us to removing it from the conn. If we race
661 * with their flag update we'll get the lock and then really
662 * see that the flag has been cleared.
663 */
664 if (!test_bit(RDS_MSG_ON_CONN, &rm->m_flags))
665 continue;
666
667 if (conn != rm->m_inc.i_conn) {
668 if (conn)
669 spin_unlock_irqrestore(&conn->c_lock, flags);
670 conn = rm->m_inc.i_conn;
671 spin_lock_irqsave(&conn->c_lock, flags);
672 }
673
674 if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) {
675 list_del_init(&rm->m_conn_item);
676 rds_message_put(rm);
677 }
678 }
679
680 if (conn)
681 spin_unlock_irqrestore(&conn->c_lock, flags);
682
683 while (!list_empty(&list)) {
684 rm = list_entry(list.next, struct rds_message, m_sock_item);
685 list_del_init(&rm->m_sock_item);
686
687 rds_message_wait(rm);
688 rds_message_put(rm);
689 }
690}
691
692/*
693 * we only want this to fire once so we use the callers 'queued'. It's
694 * possible that another thread can race with us and remove the
695 * message from the flow with RDS_CANCEL_SENT_TO.
696 */
697static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn,
698 struct rds_message *rm, __be16 sport,
699 __be16 dport, int *queued)
700{
701 unsigned long flags;
702 u32 len;
703
704 if (*queued)
705 goto out;
706
707 len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
708
709 /* this is the only place which holds both the socket's rs_lock
710 * and the connection's c_lock */
711 spin_lock_irqsave(&rs->rs_lock, flags);
712
713 /*
714 * If there is a little space in sndbuf, we don't queue anything,
715 * and userspace gets -EAGAIN. But poll() indicates there's send
716 * room. This can lead to bad behavior (spinning) if snd_bytes isn't
717 * freed up by incoming acks. So we check the *old* value of
718 * rs_snd_bytes here to allow the last msg to exceed the buffer,
719 * and poll() now knows no more data can be sent.
720 */
721 if (rs->rs_snd_bytes < rds_sk_sndbuf(rs)) {
722 rs->rs_snd_bytes += len;
723
724 /* let recv side know we are close to send space exhaustion.
725 * This is probably not the optimal way to do it, as this
726 * means we set the flag on *all* messages as soon as our
727 * throughput hits a certain threshold.
728 */
729 if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2)
730 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
731
732 list_add_tail(&rm->m_sock_item, &rs->rs_send_queue);
733 set_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
734 rds_message_addref(rm);
735 rm->m_rs = rs;
736
737 /* The code ordering is a little weird, but we're
738 trying to minimize the time we hold c_lock */
739 rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport, 0);
740 rm->m_inc.i_conn = conn;
741 rds_message_addref(rm);
742
743 spin_lock(&conn->c_lock);
744 rm->m_inc.i_hdr.h_sequence = cpu_to_be64(conn->c_next_tx_seq++);
745 list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
746 set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
747 spin_unlock(&conn->c_lock);
748
749 rdsdebug("queued msg %p len %d, rs %p bytes %d seq %llu\n",
750 rm, len, rs, rs->rs_snd_bytes,
751 (unsigned long long)be64_to_cpu(rm->m_inc.i_hdr.h_sequence));
752
753 *queued = 1;
754 }
755
756 spin_unlock_irqrestore(&rs->rs_lock, flags);
757out:
758 return *queued;
759}
760
761static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
762 struct msghdr *msg, int *allocated_mr)
763{
764 struct cmsghdr *cmsg;
765 int ret = 0;
766
767 for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
768 if (!CMSG_OK(msg, cmsg))
769 return -EINVAL;
770
771 if (cmsg->cmsg_level != SOL_RDS)
772 continue;
773
774 /* As a side effect, RDMA_DEST and RDMA_MAP will set
775 * rm->m_rdma_cookie and rm->m_rdma_mr.
776 */
777 switch (cmsg->cmsg_type) {
778 case RDS_CMSG_RDMA_ARGS:
779 ret = rds_cmsg_rdma_args(rs, rm, cmsg);
780 break;
781
782 case RDS_CMSG_RDMA_DEST:
783 ret = rds_cmsg_rdma_dest(rs, rm, cmsg);
784 break;
785
786 case RDS_CMSG_RDMA_MAP:
787 ret = rds_cmsg_rdma_map(rs, rm, cmsg);
788 if (!ret)
789 *allocated_mr = 1;
790 break;
791
792 default:
793 return -EINVAL;
794 }
795
796 if (ret)
797 break;
798 }
799
800 return ret;
801}
802
803int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
804 size_t payload_len)
805{
806 struct sock *sk = sock->sk;
807 struct rds_sock *rs = rds_sk_to_rs(sk);
808 struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name;
809 __be32 daddr;
810 __be16 dport;
811 struct rds_message *rm = NULL;
812 struct rds_connection *conn;
813 int ret = 0;
814 int queued = 0, allocated_mr = 0;
815 int nonblock = msg->msg_flags & MSG_DONTWAIT;
816 long timeo = sock_rcvtimeo(sk, nonblock);
817
818 /* Mirror Linux UDP mirror of BSD error message compatibility */
819 /* XXX: Perhaps MSG_MORE someday */
820 if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) {
821 printk(KERN_INFO "msg_flags 0x%08X\n", msg->msg_flags);
822 ret = -EOPNOTSUPP;
823 goto out;
824 }
825
826 if (msg->msg_namelen) {
827 /* XXX fail non-unicast destination IPs? */
828 if (msg->msg_namelen < sizeof(*usin) || usin->sin_family != AF_INET) {
829 ret = -EINVAL;
830 goto out;
831 }
832 daddr = usin->sin_addr.s_addr;
833 dport = usin->sin_port;
834 } else {
835 /* We only care about consistency with ->connect() */
836 lock_sock(sk);
837 daddr = rs->rs_conn_addr;
838 dport = rs->rs_conn_port;
839 release_sock(sk);
840 }
841
842 /* racing with another thread binding seems ok here */
843 if (daddr == 0 || rs->rs_bound_addr == 0) {
844 ret = -ENOTCONN; /* XXX not a great errno */
845 goto out;
846 }
847
848 rm = rds_message_copy_from_user(msg->msg_iov, payload_len);
849 if (IS_ERR(rm)) {
850 ret = PTR_ERR(rm);
851 rm = NULL;
852 goto out;
853 }
854
855 rm->m_daddr = daddr;
856
857 /* Parse any control messages the user may have included. */
858 ret = rds_cmsg_send(rs, rm, msg, &allocated_mr);
859 if (ret)
860 goto out;
861
862 /* rds_conn_create has a spinlock that runs with IRQ off.
863 * Caching the conn in the socket helps a lot. */
864 if (rs->rs_conn && rs->rs_conn->c_faddr == daddr)
865 conn = rs->rs_conn;
866 else {
867 conn = rds_conn_create_outgoing(rs->rs_bound_addr, daddr,
868 rs->rs_transport,
869 sock->sk->sk_allocation);
870 if (IS_ERR(conn)) {
871 ret = PTR_ERR(conn);
872 goto out;
873 }
874 rs->rs_conn = conn;
875 }
876
877 if ((rm->m_rdma_cookie || rm->m_rdma_op)
878 && conn->c_trans->xmit_rdma == NULL) {
879 if (printk_ratelimit())
880 printk(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",
881 rm->m_rdma_op, conn->c_trans->xmit_rdma);
882 ret = -EOPNOTSUPP;
883 goto out;
884 }
885
886 /* If the connection is down, trigger a connect. We may
887 * have scheduled a delayed reconnect however - in this case
888 * we should not interfere.
889 */
890 if (rds_conn_state(conn) == RDS_CONN_DOWN
891 && !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
892 queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
893
894 ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);
895 if (ret)
896 goto out;
897
898 while (!rds_send_queue_rm(rs, conn, rm, rs->rs_bound_port,
899 dport, &queued)) {
900 rds_stats_inc(s_send_queue_full);
901 /* XXX make sure this is reasonable */
902 if (payload_len > rds_sk_sndbuf(rs)) {
903 ret = -EMSGSIZE;
904 goto out;
905 }
906 if (nonblock) {
907 ret = -EAGAIN;
908 goto out;
909 }
910
911 timeo = wait_event_interruptible_timeout(*sk->sk_sleep,
912 rds_send_queue_rm(rs, conn, rm,
913 rs->rs_bound_port,
914 dport,
915 &queued),
916 timeo);
917 rdsdebug("sendmsg woke queued %d timeo %ld\n", queued, timeo);
918 if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
919 continue;
920
921 ret = timeo;
922 if (ret == 0)
923 ret = -ETIMEDOUT;
924 goto out;
925 }
926
927 /*
928 * By now we've committed to the send. We reuse rds_send_worker()
929 * to retry sends in the rds thread if the transport asks us to.
930 */
931 rds_stats_inc(s_send_queued);
932
933 if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
934 rds_send_worker(&conn->c_send_w.work);
935
936 rds_message_put(rm);
937 return payload_len;
938
939out:
940 /* If the user included a RDMA_MAP cmsg, we allocated a MR on the fly.
941 * If the sendmsg goes through, we keep the MR. If it fails with EAGAIN
942 * or in any other way, we need to destroy the MR again */
943 if (allocated_mr)
944 rds_rdma_unuse(rs, rds_rdma_cookie_key(rm->m_rdma_cookie), 1);
945
946 if (rm)
947 rds_message_put(rm);
948 return ret;
949}
950
951/*
952 * Reply to a ping packet.
953 */
954int
955rds_send_pong(struct rds_connection *conn, __be16 dport)
956{
957 struct rds_message *rm;
958 unsigned long flags;
959 int ret = 0;
960
961 rm = rds_message_alloc(0, GFP_ATOMIC);
962 if (rm == NULL) {
963 ret = -ENOMEM;
964 goto out;
965 }
966
967 rm->m_daddr = conn->c_faddr;
968
969 /* If the connection is down, trigger a connect. We may
970 * have scheduled a delayed reconnect however - in this case
971 * we should not interfere.
972 */
973 if (rds_conn_state(conn) == RDS_CONN_DOWN
974 && !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
975 queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
976
977 ret = rds_cong_wait(conn->c_fcong, dport, 1, NULL);
978 if (ret)
979 goto out;
980
981 spin_lock_irqsave(&conn->c_lock, flags);
982 list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
983 set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
984 rds_message_addref(rm);
985 rm->m_inc.i_conn = conn;
986
987 rds_message_populate_header(&rm->m_inc.i_hdr, 0, dport,
988 conn->c_next_tx_seq);
989 conn->c_next_tx_seq++;
990 spin_unlock_irqrestore(&conn->c_lock, flags);
991
992 rds_stats_inc(s_send_queued);
993 rds_stats_inc(s_send_pong);
994
995 queue_delayed_work(rds_wq, &conn->c_send_w, 0);
996 rds_message_put(rm);
997 return 0;
998
999out:
1000 if (rm)
1001 rds_message_put(rm);
1002 return ret;
1003}