blob: b2fccfc207690f5bfa231af389031a7dce8a218b [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 */
Joe Perchesf64f9e72009-11-29 16:55:45 -0800238 if (rm->m_rdma_op &&
239 test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) {
Andy Grover5c115592009-02-24 15:30:27 +0000240 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);
Joe Perchesf64f9e72009-11-29 16:55:45 -0800250 if (conn->c_unacked_packets == 0 ||
251 conn->c_unacked_bytes < len) {
Andy Grover5c115592009-02-24 15:30:27 +0000252 __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;
Joe Perchesf64f9e72009-11-29 16:55:45 -0800421 if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) &&
422 ro && ro->r_notify && ro->r_notifier) {
Andy Grover5c115592009-02-24 15:30:27 +0000423 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}
Andy Grover616b7572009-08-21 12:28:32 +0000442EXPORT_SYMBOL_GPL(rds_rdma_send_complete);
Andy Grover5c115592009-02-24 15:30:27 +0000443
444/*
445 * This is the same as rds_rdma_send_complete except we
446 * don't do any locking - we have all the ingredients (message,
447 * socket, socket lock) and can just move the notifier.
448 */
449static inline void
450__rds_rdma_send_complete(struct rds_sock *rs, struct rds_message *rm, int status)
451{
452 struct rds_rdma_op *ro;
453
454 ro = rm->m_rdma_op;
455 if (ro && ro->r_notify && ro->r_notifier) {
456 ro->r_notifier->n_status = status;
457 list_add_tail(&ro->r_notifier->n_list, &rs->rs_notify_queue);
458 ro->r_notifier = NULL;
459 }
460
461 /* No need to wake the app - caller does this */
462}
463
464/*
465 * This is called from the IB send completion when we detect
466 * a RDMA operation that failed with remote access error.
467 * So speed is not an issue here.
468 */
469struct rds_message *rds_send_get_message(struct rds_connection *conn,
470 struct rds_rdma_op *op)
471{
472 struct rds_message *rm, *tmp, *found = NULL;
473 unsigned long flags;
474
475 spin_lock_irqsave(&conn->c_lock, flags);
476
477 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
478 if (rm->m_rdma_op == op) {
479 atomic_inc(&rm->m_refcount);
480 found = rm;
481 goto out;
482 }
483 }
484
485 list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
486 if (rm->m_rdma_op == op) {
487 atomic_inc(&rm->m_refcount);
488 found = rm;
489 break;
490 }
491 }
492
493out:
494 spin_unlock_irqrestore(&conn->c_lock, flags);
495
496 return found;
497}
Andy Grover616b7572009-08-21 12:28:32 +0000498EXPORT_SYMBOL_GPL(rds_send_get_message);
Andy Grover5c115592009-02-24 15:30:27 +0000499
500/*
501 * This removes messages from the socket's list if they're on it. The list
502 * argument must be private to the caller, we must be able to modify it
503 * without locks. The messages must have a reference held for their
504 * position on the list. This function will drop that reference after
505 * removing the messages from the 'messages' list regardless of if it found
506 * the messages on the socket list or not.
507 */
508void rds_send_remove_from_sock(struct list_head *messages, int status)
509{
510 unsigned long flags = 0; /* silence gcc :P */
511 struct rds_sock *rs = NULL;
512 struct rds_message *rm;
513
514 local_irq_save(flags);
515 while (!list_empty(messages)) {
516 rm = list_entry(messages->next, struct rds_message,
517 m_conn_item);
518 list_del_init(&rm->m_conn_item);
519
520 /*
521 * If we see this flag cleared then we're *sure* that someone
522 * else beat us to removing it from the sock. If we race
523 * with their flag update we'll get the lock and then really
524 * see that the flag has been cleared.
525 *
526 * The message spinlock makes sure nobody clears rm->m_rs
527 * while we're messing with it. It does not prevent the
528 * message from being removed from the socket, though.
529 */
530 spin_lock(&rm->m_rs_lock);
531 if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags))
532 goto unlock_and_drop;
533
534 if (rs != rm->m_rs) {
535 if (rs) {
536 spin_unlock(&rs->rs_lock);
537 rds_wake_sk_sleep(rs);
538 sock_put(rds_rs_to_sk(rs));
539 }
540 rs = rm->m_rs;
541 spin_lock(&rs->rs_lock);
542 sock_hold(rds_rs_to_sk(rs));
543 }
544
545 if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) {
546 struct rds_rdma_op *ro = rm->m_rdma_op;
547 struct rds_notifier *notifier;
548
549 list_del_init(&rm->m_sock_item);
550 rds_send_sndbuf_remove(rs, rm);
551
Joe Perchesf64f9e72009-11-29 16:55:45 -0800552 if (ro && ro->r_notifier && (status || ro->r_notify)) {
Andy Grover5c115592009-02-24 15:30:27 +0000553 notifier = ro->r_notifier;
554 list_add_tail(&notifier->n_list,
555 &rs->rs_notify_queue);
556 if (!notifier->n_status)
557 notifier->n_status = status;
558 rm->m_rdma_op->r_notifier = NULL;
559 }
560 rds_message_put(rm);
561 rm->m_rs = NULL;
562 }
563
564unlock_and_drop:
565 spin_unlock(&rm->m_rs_lock);
566 rds_message_put(rm);
567 }
568
569 if (rs) {
570 spin_unlock(&rs->rs_lock);
571 rds_wake_sk_sleep(rs);
572 sock_put(rds_rs_to_sk(rs));
573 }
574 local_irq_restore(flags);
575}
576
577/*
578 * Transports call here when they've determined that the receiver queued
579 * messages up to, and including, the given sequence number. Messages are
580 * moved to the retrans queue when rds_send_xmit picks them off the send
581 * queue. This means that in the TCP case, the message may not have been
582 * assigned the m_ack_seq yet - but that's fine as long as tcp_is_acked
583 * checks the RDS_MSG_HAS_ACK_SEQ bit.
584 *
585 * XXX It's not clear to me how this is safely serialized with socket
586 * destruction. Maybe it should bail if it sees SOCK_DEAD.
587 */
588void rds_send_drop_acked(struct rds_connection *conn, u64 ack,
589 is_acked_func is_acked)
590{
591 struct rds_message *rm, *tmp;
592 unsigned long flags;
593 LIST_HEAD(list);
594
595 spin_lock_irqsave(&conn->c_lock, flags);
596
597 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
598 if (!rds_send_is_acked(rm, ack, is_acked))
599 break;
600
601 list_move(&rm->m_conn_item, &list);
602 clear_bit(RDS_MSG_ON_CONN, &rm->m_flags);
603 }
604
605 /* order flag updates with spin locks */
606 if (!list_empty(&list))
607 smp_mb__after_clear_bit();
608
609 spin_unlock_irqrestore(&conn->c_lock, flags);
610
611 /* now remove the messages from the sock list as needed */
612 rds_send_remove_from_sock(&list, RDS_RDMA_SUCCESS);
613}
Andy Grover616b7572009-08-21 12:28:32 +0000614EXPORT_SYMBOL_GPL(rds_send_drop_acked);
Andy Grover5c115592009-02-24 15:30:27 +0000615
616void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest)
617{
618 struct rds_message *rm, *tmp;
619 struct rds_connection *conn;
Andy Groverf1cffcb2009-04-01 08:20:18 +0000620 unsigned long flags, flags2;
Andy Grover5c115592009-02-24 15:30:27 +0000621 LIST_HEAD(list);
622 int wake = 0;
623
624 /* get all the messages we're dropping under the rs lock */
625 spin_lock_irqsave(&rs->rs_lock, flags);
626
627 list_for_each_entry_safe(rm, tmp, &rs->rs_send_queue, m_sock_item) {
628 if (dest && (dest->sin_addr.s_addr != rm->m_daddr ||
629 dest->sin_port != rm->m_inc.i_hdr.h_dport))
630 continue;
631
632 wake = 1;
633 list_move(&rm->m_sock_item, &list);
634 rds_send_sndbuf_remove(rs, rm);
635 clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
636
637 /* If this is a RDMA operation, notify the app. */
638 __rds_rdma_send_complete(rs, rm, RDS_RDMA_CANCELED);
639 }
640
641 /* order flag updates with the rs lock */
642 if (wake)
643 smp_mb__after_clear_bit();
644
645 spin_unlock_irqrestore(&rs->rs_lock, flags);
646
647 if (wake)
648 rds_wake_sk_sleep(rs);
649
650 conn = NULL;
651
652 /* now remove the messages from the conn list as needed */
653 list_for_each_entry(rm, &list, m_sock_item) {
654 /* We do this here rather than in the loop above, so that
655 * we don't have to nest m_rs_lock under rs->rs_lock */
Andy Groverf1cffcb2009-04-01 08:20:18 +0000656 spin_lock_irqsave(&rm->m_rs_lock, flags2);
Andy Grover5c115592009-02-24 15:30:27 +0000657 rm->m_rs = NULL;
Andy Groverf1cffcb2009-04-01 08:20:18 +0000658 spin_unlock_irqrestore(&rm->m_rs_lock, flags2);
Andy Grover5c115592009-02-24 15:30:27 +0000659
660 /*
661 * If we see this flag cleared then we're *sure* that someone
662 * else beat us to removing it from the conn. If we race
663 * with their flag update we'll get the lock and then really
664 * see that the flag has been cleared.
665 */
666 if (!test_bit(RDS_MSG_ON_CONN, &rm->m_flags))
667 continue;
668
669 if (conn != rm->m_inc.i_conn) {
670 if (conn)
671 spin_unlock_irqrestore(&conn->c_lock, flags);
672 conn = rm->m_inc.i_conn;
673 spin_lock_irqsave(&conn->c_lock, flags);
674 }
675
676 if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) {
677 list_del_init(&rm->m_conn_item);
678 rds_message_put(rm);
679 }
680 }
681
682 if (conn)
683 spin_unlock_irqrestore(&conn->c_lock, flags);
684
685 while (!list_empty(&list)) {
686 rm = list_entry(list.next, struct rds_message, m_sock_item);
687 list_del_init(&rm->m_sock_item);
688
689 rds_message_wait(rm);
690 rds_message_put(rm);
691 }
692}
693
694/*
695 * we only want this to fire once so we use the callers 'queued'. It's
696 * possible that another thread can race with us and remove the
697 * message from the flow with RDS_CANCEL_SENT_TO.
698 */
699static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn,
700 struct rds_message *rm, __be16 sport,
701 __be16 dport, int *queued)
702{
703 unsigned long flags;
704 u32 len;
705
706 if (*queued)
707 goto out;
708
709 len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
710
711 /* this is the only place which holds both the socket's rs_lock
712 * and the connection's c_lock */
713 spin_lock_irqsave(&rs->rs_lock, flags);
714
715 /*
716 * If there is a little space in sndbuf, we don't queue anything,
717 * and userspace gets -EAGAIN. But poll() indicates there's send
718 * room. This can lead to bad behavior (spinning) if snd_bytes isn't
719 * freed up by incoming acks. So we check the *old* value of
720 * rs_snd_bytes here to allow the last msg to exceed the buffer,
721 * and poll() now knows no more data can be sent.
722 */
723 if (rs->rs_snd_bytes < rds_sk_sndbuf(rs)) {
724 rs->rs_snd_bytes += len;
725
726 /* let recv side know we are close to send space exhaustion.
727 * This is probably not the optimal way to do it, as this
728 * means we set the flag on *all* messages as soon as our
729 * throughput hits a certain threshold.
730 */
731 if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2)
732 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
733
734 list_add_tail(&rm->m_sock_item, &rs->rs_send_queue);
735 set_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
736 rds_message_addref(rm);
737 rm->m_rs = rs;
738
739 /* The code ordering is a little weird, but we're
740 trying to minimize the time we hold c_lock */
741 rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport, 0);
742 rm->m_inc.i_conn = conn;
743 rds_message_addref(rm);
744
745 spin_lock(&conn->c_lock);
746 rm->m_inc.i_hdr.h_sequence = cpu_to_be64(conn->c_next_tx_seq++);
747 list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
748 set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
749 spin_unlock(&conn->c_lock);
750
751 rdsdebug("queued msg %p len %d, rs %p bytes %d seq %llu\n",
752 rm, len, rs, rs->rs_snd_bytes,
753 (unsigned long long)be64_to_cpu(rm->m_inc.i_hdr.h_sequence));
754
755 *queued = 1;
756 }
757
758 spin_unlock_irqrestore(&rs->rs_lock, flags);
759out:
760 return *queued;
761}
762
763static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
764 struct msghdr *msg, int *allocated_mr)
765{
766 struct cmsghdr *cmsg;
767 int ret = 0;
768
769 for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
770 if (!CMSG_OK(msg, cmsg))
771 return -EINVAL;
772
773 if (cmsg->cmsg_level != SOL_RDS)
774 continue;
775
776 /* As a side effect, RDMA_DEST and RDMA_MAP will set
777 * rm->m_rdma_cookie and rm->m_rdma_mr.
778 */
779 switch (cmsg->cmsg_type) {
780 case RDS_CMSG_RDMA_ARGS:
781 ret = rds_cmsg_rdma_args(rs, rm, cmsg);
782 break;
783
784 case RDS_CMSG_RDMA_DEST:
785 ret = rds_cmsg_rdma_dest(rs, rm, cmsg);
786 break;
787
788 case RDS_CMSG_RDMA_MAP:
789 ret = rds_cmsg_rdma_map(rs, rm, cmsg);
790 if (!ret)
791 *allocated_mr = 1;
792 break;
793
794 default:
795 return -EINVAL;
796 }
797
798 if (ret)
799 break;
800 }
801
802 return ret;
803}
804
805int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
806 size_t payload_len)
807{
808 struct sock *sk = sock->sk;
809 struct rds_sock *rs = rds_sk_to_rs(sk);
810 struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name;
811 __be32 daddr;
812 __be16 dport;
813 struct rds_message *rm = NULL;
814 struct rds_connection *conn;
815 int ret = 0;
816 int queued = 0, allocated_mr = 0;
817 int nonblock = msg->msg_flags & MSG_DONTWAIT;
818 long timeo = sock_rcvtimeo(sk, nonblock);
819
820 /* Mirror Linux UDP mirror of BSD error message compatibility */
821 /* XXX: Perhaps MSG_MORE someday */
822 if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) {
823 printk(KERN_INFO "msg_flags 0x%08X\n", msg->msg_flags);
824 ret = -EOPNOTSUPP;
825 goto out;
826 }
827
828 if (msg->msg_namelen) {
829 /* XXX fail non-unicast destination IPs? */
830 if (msg->msg_namelen < sizeof(*usin) || usin->sin_family != AF_INET) {
831 ret = -EINVAL;
832 goto out;
833 }
834 daddr = usin->sin_addr.s_addr;
835 dport = usin->sin_port;
836 } else {
837 /* We only care about consistency with ->connect() */
838 lock_sock(sk);
839 daddr = rs->rs_conn_addr;
840 dport = rs->rs_conn_port;
841 release_sock(sk);
842 }
843
844 /* racing with another thread binding seems ok here */
845 if (daddr == 0 || rs->rs_bound_addr == 0) {
846 ret = -ENOTCONN; /* XXX not a great errno */
847 goto out;
848 }
849
850 rm = rds_message_copy_from_user(msg->msg_iov, payload_len);
851 if (IS_ERR(rm)) {
852 ret = PTR_ERR(rm);
853 rm = NULL;
854 goto out;
855 }
856
857 rm->m_daddr = daddr;
858
Andy Grover5c115592009-02-24 15:30:27 +0000859 /* rds_conn_create has a spinlock that runs with IRQ off.
860 * Caching the conn in the socket helps a lot. */
861 if (rs->rs_conn && rs->rs_conn->c_faddr == daddr)
862 conn = rs->rs_conn;
863 else {
864 conn = rds_conn_create_outgoing(rs->rs_bound_addr, daddr,
865 rs->rs_transport,
866 sock->sk->sk_allocation);
867 if (IS_ERR(conn)) {
868 ret = PTR_ERR(conn);
869 goto out;
870 }
871 rs->rs_conn = conn;
872 }
873
Andy Grover49f69692009-04-09 14:09:41 +0000874 /* Parse any control messages the user may have included. */
875 ret = rds_cmsg_send(rs, rm, msg, &allocated_mr);
876 if (ret)
877 goto out;
878
Joe Perchesf64f9e72009-11-29 16:55:45 -0800879 if ((rm->m_rdma_cookie || rm->m_rdma_op) &&
880 conn->c_trans->xmit_rdma == NULL) {
Andy Grover5c115592009-02-24 15:30:27 +0000881 if (printk_ratelimit())
882 printk(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",
883 rm->m_rdma_op, conn->c_trans->xmit_rdma);
884 ret = -EOPNOTSUPP;
885 goto out;
886 }
887
888 /* If the connection is down, trigger a connect. We may
889 * have scheduled a delayed reconnect however - in this case
890 * we should not interfere.
891 */
Joe Perchesf64f9e72009-11-29 16:55:45 -0800892 if (rds_conn_state(conn) == RDS_CONN_DOWN &&
893 !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
Andy Grover5c115592009-02-24 15:30:27 +0000894 queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
895
896 ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);
897 if (ret)
898 goto out;
899
900 while (!rds_send_queue_rm(rs, conn, rm, rs->rs_bound_port,
901 dport, &queued)) {
902 rds_stats_inc(s_send_queue_full);
903 /* XXX make sure this is reasonable */
904 if (payload_len > rds_sk_sndbuf(rs)) {
905 ret = -EMSGSIZE;
906 goto out;
907 }
908 if (nonblock) {
909 ret = -EAGAIN;
910 goto out;
911 }
912
913 timeo = wait_event_interruptible_timeout(*sk->sk_sleep,
914 rds_send_queue_rm(rs, conn, rm,
915 rs->rs_bound_port,
916 dport,
917 &queued),
918 timeo);
919 rdsdebug("sendmsg woke queued %d timeo %ld\n", queued, timeo);
920 if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
921 continue;
922
923 ret = timeo;
924 if (ret == 0)
925 ret = -ETIMEDOUT;
926 goto out;
927 }
928
929 /*
930 * By now we've committed to the send. We reuse rds_send_worker()
931 * to retry sends in the rds thread if the transport asks us to.
932 */
933 rds_stats_inc(s_send_queued);
934
935 if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
936 rds_send_worker(&conn->c_send_w.work);
937
938 rds_message_put(rm);
939 return payload_len;
940
941out:
942 /* If the user included a RDMA_MAP cmsg, we allocated a MR on the fly.
943 * If the sendmsg goes through, we keep the MR. If it fails with EAGAIN
944 * or in any other way, we need to destroy the MR again */
945 if (allocated_mr)
946 rds_rdma_unuse(rs, rds_rdma_cookie_key(rm->m_rdma_cookie), 1);
947
948 if (rm)
949 rds_message_put(rm);
950 return ret;
951}
952
953/*
954 * Reply to a ping packet.
955 */
956int
957rds_send_pong(struct rds_connection *conn, __be16 dport)
958{
959 struct rds_message *rm;
960 unsigned long flags;
961 int ret = 0;
962
963 rm = rds_message_alloc(0, GFP_ATOMIC);
964 if (rm == NULL) {
965 ret = -ENOMEM;
966 goto out;
967 }
968
969 rm->m_daddr = conn->c_faddr;
970
971 /* If the connection is down, trigger a connect. We may
972 * have scheduled a delayed reconnect however - in this case
973 * we should not interfere.
974 */
Joe Perchesf64f9e72009-11-29 16:55:45 -0800975 if (rds_conn_state(conn) == RDS_CONN_DOWN &&
976 !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
Andy Grover5c115592009-02-24 15:30:27 +0000977 queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
978
979 ret = rds_cong_wait(conn->c_fcong, dport, 1, NULL);
980 if (ret)
981 goto out;
982
983 spin_lock_irqsave(&conn->c_lock, flags);
984 list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
985 set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
986 rds_message_addref(rm);
987 rm->m_inc.i_conn = conn;
988
989 rds_message_populate_header(&rm->m_inc.i_hdr, 0, dport,
990 conn->c_next_tx_seq);
991 conn->c_next_tx_seq++;
992 spin_unlock_irqrestore(&conn->c_lock, flags);
993
994 rds_stats_inc(s_send_queued);
995 rds_stats_inc(s_send_pong);
996
997 queue_delayed_work(rds_wq, &conn->c_send_w, 0);
998 rds_message_put(rm);
999 return 0;
1000
1001out:
1002 if (rm)
1003 rds_message_put(rm);
1004 return ret;
1005}