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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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090034#include <linux/gfp.h>
Andy Grover5c115592009-02-24 15:30:27 +000035#include <net/sock.h>
36#include <linux/in.h>
37#include <linux/list.h>
38
39#include "rds.h"
40#include "rdma.h"
41
42/* When transmitting messages in rds_send_xmit, we need to emerge from
43 * time to time and briefly release the CPU. Otherwise the softlock watchdog
44 * will kick our shin.
45 * Also, it seems fairer to not let one busy connection stall all the
46 * others.
47 *
48 * send_batch_count is the number of times we'll loop in send_xmit. Setting
49 * it to 0 will restore the old behavior (where we looped until we had
50 * drained the queue).
51 */
52static int send_batch_count = 64;
53module_param(send_batch_count, int, 0444);
54MODULE_PARM_DESC(send_batch_count, " batch factor when working the send queue");
55
56/*
57 * Reset the send state. Caller must hold c_send_lock when calling here.
58 */
59void rds_send_reset(struct rds_connection *conn)
60{
61 struct rds_message *rm, *tmp;
62 unsigned long flags;
63
64 if (conn->c_xmit_rm) {
65 /* Tell the user the RDMA op is no longer mapped by the
66 * transport. This isn't entirely true (it's flushed out
67 * independently) but as the connection is down, there's
68 * no ongoing RDMA to/from that memory */
69 rds_message_unmapped(conn->c_xmit_rm);
70 rds_message_put(conn->c_xmit_rm);
71 conn->c_xmit_rm = NULL;
72 }
73 conn->c_xmit_sg = 0;
74 conn->c_xmit_hdr_off = 0;
75 conn->c_xmit_data_off = 0;
76 conn->c_xmit_rdma_sent = 0;
77
78 conn->c_map_queued = 0;
79
80 conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
81 conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
82
83 /* Mark messages as retransmissions, and move them to the send q */
84 spin_lock_irqsave(&conn->c_lock, flags);
85 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
86 set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
87 set_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags);
88 }
89 list_splice_init(&conn->c_retrans, &conn->c_send_queue);
90 spin_unlock_irqrestore(&conn->c_lock, flags);
91}
92
93/*
94 * We're making the concious trade-off here to only send one message
95 * down the connection at a time.
96 * Pro:
97 * - tx queueing is a simple fifo list
98 * - reassembly is optional and easily done by transports per conn
99 * - no per flow rx lookup at all, straight to the socket
100 * - less per-frag memory and wire overhead
101 * Con:
102 * - queued acks can be delayed behind large messages
103 * Depends:
104 * - small message latency is higher behind queued large messages
105 * - large message latency isn't starved by intervening small sends
106 */
107int rds_send_xmit(struct rds_connection *conn)
108{
109 struct rds_message *rm;
110 unsigned long flags;
111 unsigned int tmp;
112 unsigned int send_quota = send_batch_count;
113 struct scatterlist *sg;
114 int ret = 0;
115 int was_empty = 0;
116 LIST_HEAD(to_be_dropped);
117
118 /*
119 * sendmsg calls here after having queued its message on the send
120 * queue. We only have one task feeding the connection at a time. If
121 * another thread is already feeding the queue then we back off. This
122 * avoids blocking the caller and trading per-connection data between
123 * caches per message.
124 *
125 * The sem holder will issue a retry if they notice that someone queued
126 * a message after they stopped walking the send queue but before they
127 * dropped the sem.
128 */
129 if (!mutex_trylock(&conn->c_send_lock)) {
130 rds_stats_inc(s_send_sem_contention);
131 ret = -ENOMEM;
132 goto out;
133 }
134
135 if (conn->c_trans->xmit_prepare)
136 conn->c_trans->xmit_prepare(conn);
137
138 /*
139 * spin trying to push headers and data down the connection until
140 * the connection doens't make forward progress.
141 */
142 while (--send_quota) {
143 /*
144 * See if need to send a congestion map update if we're
145 * between sending messages. The send_sem protects our sole
146 * use of c_map_offset and _bytes.
147 * Note this is used only by transports that define a special
148 * xmit_cong_map function. For all others, we create allocate
149 * a cong_map message and treat it just like any other send.
150 */
151 if (conn->c_map_bytes) {
152 ret = conn->c_trans->xmit_cong_map(conn, conn->c_lcong,
153 conn->c_map_offset);
154 if (ret <= 0)
155 break;
156
157 conn->c_map_offset += ret;
158 conn->c_map_bytes -= ret;
159 if (conn->c_map_bytes)
160 continue;
161 }
162
163 /* If we're done sending the current message, clear the
164 * offset and S/G temporaries.
165 */
166 rm = conn->c_xmit_rm;
167 if (rm != NULL &&
168 conn->c_xmit_hdr_off == sizeof(struct rds_header) &&
169 conn->c_xmit_sg == rm->m_nents) {
170 conn->c_xmit_rm = NULL;
171 conn->c_xmit_sg = 0;
172 conn->c_xmit_hdr_off = 0;
173 conn->c_xmit_data_off = 0;
174 conn->c_xmit_rdma_sent = 0;
175
176 /* Release the reference to the previous message. */
177 rds_message_put(rm);
178 rm = NULL;
179 }
180
181 /* If we're asked to send a cong map update, do so.
182 */
183 if (rm == NULL && test_and_clear_bit(0, &conn->c_map_queued)) {
184 if (conn->c_trans->xmit_cong_map != NULL) {
185 conn->c_map_offset = 0;
186 conn->c_map_bytes = sizeof(struct rds_header) +
187 RDS_CONG_MAP_BYTES;
188 continue;
189 }
190
191 rm = rds_cong_update_alloc(conn);
192 if (IS_ERR(rm)) {
193 ret = PTR_ERR(rm);
194 break;
195 }
196
197 conn->c_xmit_rm = rm;
198 }
199
200 /*
201 * Grab the next message from the send queue, if there is one.
202 *
203 * c_xmit_rm holds a ref while we're sending this message down
204 * the connction. We can use this ref while holding the
205 * send_sem.. rds_send_reset() is serialized with it.
206 */
207 if (rm == NULL) {
208 unsigned int len;
209
210 spin_lock_irqsave(&conn->c_lock, flags);
211
212 if (!list_empty(&conn->c_send_queue)) {
213 rm = list_entry(conn->c_send_queue.next,
214 struct rds_message,
215 m_conn_item);
216 rds_message_addref(rm);
217
218 /*
219 * Move the message from the send queue to the retransmit
220 * list right away.
221 */
222 list_move_tail(&rm->m_conn_item, &conn->c_retrans);
223 }
224
225 spin_unlock_irqrestore(&conn->c_lock, flags);
226
227 if (rm == NULL) {
228 was_empty = 1;
229 break;
230 }
231
232 /* Unfortunately, the way Infiniband deals with
233 * RDMA to a bad MR key is by moving the entire
234 * queue pair to error state. We cold possibly
235 * recover from that, but right now we drop the
236 * connection.
237 * Therefore, we never retransmit messages with RDMA ops.
238 */
Joe Perchesf64f9e72009-11-29 16:55:45 -0800239 if (rm->m_rdma_op &&
240 test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) {
Andy Grover5c115592009-02-24 15:30:27 +0000241 spin_lock_irqsave(&conn->c_lock, flags);
242 if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags))
243 list_move(&rm->m_conn_item, &to_be_dropped);
244 spin_unlock_irqrestore(&conn->c_lock, flags);
245 rds_message_put(rm);
246 continue;
247 }
248
249 /* Require an ACK every once in a while */
250 len = ntohl(rm->m_inc.i_hdr.h_len);
Joe Perchesf64f9e72009-11-29 16:55:45 -0800251 if (conn->c_unacked_packets == 0 ||
252 conn->c_unacked_bytes < len) {
Andy Grover5c115592009-02-24 15:30:27 +0000253 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
254
255 conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
256 conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
257 rds_stats_inc(s_send_ack_required);
258 } else {
259 conn->c_unacked_bytes -= len;
260 conn->c_unacked_packets--;
261 }
262
263 conn->c_xmit_rm = rm;
264 }
265
266 /*
267 * Try and send an rdma message. Let's see if we can
268 * keep this simple and require that the transport either
269 * send the whole rdma or none of it.
270 */
271 if (rm->m_rdma_op && !conn->c_xmit_rdma_sent) {
272 ret = conn->c_trans->xmit_rdma(conn, rm->m_rdma_op);
273 if (ret)
274 break;
275 conn->c_xmit_rdma_sent = 1;
276 /* The transport owns the mapped memory for now.
277 * You can't unmap it while it's on the send queue */
278 set_bit(RDS_MSG_MAPPED, &rm->m_flags);
279 }
280
281 if (conn->c_xmit_hdr_off < sizeof(struct rds_header) ||
282 conn->c_xmit_sg < rm->m_nents) {
283 ret = conn->c_trans->xmit(conn, rm,
284 conn->c_xmit_hdr_off,
285 conn->c_xmit_sg,
286 conn->c_xmit_data_off);
287 if (ret <= 0)
288 break;
289
290 if (conn->c_xmit_hdr_off < sizeof(struct rds_header)) {
291 tmp = min_t(int, ret,
292 sizeof(struct rds_header) -
293 conn->c_xmit_hdr_off);
294 conn->c_xmit_hdr_off += tmp;
295 ret -= tmp;
296 }
297
298 sg = &rm->m_sg[conn->c_xmit_sg];
299 while (ret) {
300 tmp = min_t(int, ret, sg->length -
301 conn->c_xmit_data_off);
302 conn->c_xmit_data_off += tmp;
303 ret -= tmp;
304 if (conn->c_xmit_data_off == sg->length) {
305 conn->c_xmit_data_off = 0;
306 sg++;
307 conn->c_xmit_sg++;
308 BUG_ON(ret != 0 &&
309 conn->c_xmit_sg == rm->m_nents);
310 }
311 }
312 }
313 }
314
315 /* Nuke any messages we decided not to retransmit. */
316 if (!list_empty(&to_be_dropped))
317 rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED);
318
319 if (conn->c_trans->xmit_complete)
320 conn->c_trans->xmit_complete(conn);
321
322 /*
323 * We might be racing with another sender who queued a message but
324 * backed off on noticing that we held the c_send_lock. If we check
325 * for queued messages after dropping the sem then either we'll
326 * see the queued message or the queuer will get the sem. If we
327 * notice the queued message then we trigger an immediate retry.
328 *
329 * We need to be careful only to do this when we stopped processing
330 * the send queue because it was empty. It's the only way we
331 * stop processing the loop when the transport hasn't taken
332 * responsibility for forward progress.
333 */
334 mutex_unlock(&conn->c_send_lock);
335
336 if (conn->c_map_bytes || (send_quota == 0 && !was_empty)) {
337 /* We exhausted the send quota, but there's work left to
338 * do. Return and (re-)schedule the send worker.
339 */
340 ret = -EAGAIN;
341 }
342
343 if (ret == 0 && was_empty) {
344 /* A simple bit test would be way faster than taking the
345 * spin lock */
346 spin_lock_irqsave(&conn->c_lock, flags);
347 if (!list_empty(&conn->c_send_queue)) {
348 rds_stats_inc(s_send_sem_queue_raced);
349 ret = -EAGAIN;
350 }
351 spin_unlock_irqrestore(&conn->c_lock, flags);
352 }
353out:
354 return ret;
355}
356
357static void rds_send_sndbuf_remove(struct rds_sock *rs, struct rds_message *rm)
358{
359 u32 len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
360
361 assert_spin_locked(&rs->rs_lock);
362
363 BUG_ON(rs->rs_snd_bytes < len);
364 rs->rs_snd_bytes -= len;
365
366 if (rs->rs_snd_bytes == 0)
367 rds_stats_inc(s_send_queue_empty);
368}
369
370static inline int rds_send_is_acked(struct rds_message *rm, u64 ack,
371 is_acked_func is_acked)
372{
373 if (is_acked)
374 return is_acked(rm, ack);
375 return be64_to_cpu(rm->m_inc.i_hdr.h_sequence) <= ack;
376}
377
378/*
379 * Returns true if there are no messages on the send and retransmit queues
380 * which have a sequence number greater than or equal to the given sequence
381 * number.
382 */
383int rds_send_acked_before(struct rds_connection *conn, u64 seq)
384{
385 struct rds_message *rm, *tmp;
386 int ret = 1;
387
388 spin_lock(&conn->c_lock);
389
390 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
391 if (be64_to_cpu(rm->m_inc.i_hdr.h_sequence) < seq)
392 ret = 0;
393 break;
394 }
395
396 list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
397 if (be64_to_cpu(rm->m_inc.i_hdr.h_sequence) < seq)
398 ret = 0;
399 break;
400 }
401
402 spin_unlock(&conn->c_lock);
403
404 return ret;
405}
406
407/*
408 * This is pretty similar to what happens below in the ACK
409 * handling code - except that we call here as soon as we get
410 * the IB send completion on the RDMA op and the accompanying
411 * message.
412 */
413void rds_rdma_send_complete(struct rds_message *rm, int status)
414{
415 struct rds_sock *rs = NULL;
416 struct rds_rdma_op *ro;
417 struct rds_notifier *notifier;
418
419 spin_lock(&rm->m_rs_lock);
420
421 ro = rm->m_rdma_op;
Joe Perchesf64f9e72009-11-29 16:55:45 -0800422 if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) &&
423 ro && ro->r_notify && ro->r_notifier) {
Andy Grover5c115592009-02-24 15:30:27 +0000424 notifier = ro->r_notifier;
425 rs = rm->m_rs;
426 sock_hold(rds_rs_to_sk(rs));
427
428 notifier->n_status = status;
429 spin_lock(&rs->rs_lock);
430 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
431 spin_unlock(&rs->rs_lock);
432
433 ro->r_notifier = NULL;
434 }
435
436 spin_unlock(&rm->m_rs_lock);
437
438 if (rs) {
439 rds_wake_sk_sleep(rs);
440 sock_put(rds_rs_to_sk(rs));
441 }
442}
Andy Grover616b7572009-08-21 12:28:32 +0000443EXPORT_SYMBOL_GPL(rds_rdma_send_complete);
Andy Grover5c115592009-02-24 15:30:27 +0000444
445/*
446 * This is the same as rds_rdma_send_complete except we
447 * don't do any locking - we have all the ingredients (message,
448 * socket, socket lock) and can just move the notifier.
449 */
450static inline void
451__rds_rdma_send_complete(struct rds_sock *rs, struct rds_message *rm, int status)
452{
453 struct rds_rdma_op *ro;
454
455 ro = rm->m_rdma_op;
456 if (ro && ro->r_notify && ro->r_notifier) {
457 ro->r_notifier->n_status = status;
458 list_add_tail(&ro->r_notifier->n_list, &rs->rs_notify_queue);
459 ro->r_notifier = NULL;
460 }
461
462 /* No need to wake the app - caller does this */
463}
464
465/*
466 * This is called from the IB send completion when we detect
467 * a RDMA operation that failed with remote access error.
468 * So speed is not an issue here.
469 */
470struct rds_message *rds_send_get_message(struct rds_connection *conn,
471 struct rds_rdma_op *op)
472{
473 struct rds_message *rm, *tmp, *found = NULL;
474 unsigned long flags;
475
476 spin_lock_irqsave(&conn->c_lock, flags);
477
478 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
479 if (rm->m_rdma_op == op) {
480 atomic_inc(&rm->m_refcount);
481 found = rm;
482 goto out;
483 }
484 }
485
486 list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
487 if (rm->m_rdma_op == op) {
488 atomic_inc(&rm->m_refcount);
489 found = rm;
490 break;
491 }
492 }
493
494out:
495 spin_unlock_irqrestore(&conn->c_lock, flags);
496
497 return found;
498}
Andy Grover616b7572009-08-21 12:28:32 +0000499EXPORT_SYMBOL_GPL(rds_send_get_message);
Andy Grover5c115592009-02-24 15:30:27 +0000500
501/*
502 * This removes messages from the socket's list if they're on it. The list
503 * argument must be private to the caller, we must be able to modify it
504 * without locks. The messages must have a reference held for their
505 * position on the list. This function will drop that reference after
506 * removing the messages from the 'messages' list regardless of if it found
507 * the messages on the socket list or not.
508 */
509void rds_send_remove_from_sock(struct list_head *messages, int status)
510{
511 unsigned long flags = 0; /* silence gcc :P */
512 struct rds_sock *rs = NULL;
513 struct rds_message *rm;
514
515 local_irq_save(flags);
516 while (!list_empty(messages)) {
517 rm = list_entry(messages->next, struct rds_message,
518 m_conn_item);
519 list_del_init(&rm->m_conn_item);
520
521 /*
522 * If we see this flag cleared then we're *sure* that someone
523 * else beat us to removing it from the sock. If we race
524 * with their flag update we'll get the lock and then really
525 * see that the flag has been cleared.
526 *
527 * The message spinlock makes sure nobody clears rm->m_rs
528 * while we're messing with it. It does not prevent the
529 * message from being removed from the socket, though.
530 */
531 spin_lock(&rm->m_rs_lock);
532 if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags))
533 goto unlock_and_drop;
534
535 if (rs != rm->m_rs) {
536 if (rs) {
537 spin_unlock(&rs->rs_lock);
538 rds_wake_sk_sleep(rs);
539 sock_put(rds_rs_to_sk(rs));
540 }
541 rs = rm->m_rs;
542 spin_lock(&rs->rs_lock);
543 sock_hold(rds_rs_to_sk(rs));
544 }
545
546 if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) {
547 struct rds_rdma_op *ro = rm->m_rdma_op;
548 struct rds_notifier *notifier;
549
550 list_del_init(&rm->m_sock_item);
551 rds_send_sndbuf_remove(rs, rm);
552
Joe Perchesf64f9e72009-11-29 16:55:45 -0800553 if (ro && ro->r_notifier && (status || ro->r_notify)) {
Andy Grover5c115592009-02-24 15:30:27 +0000554 notifier = ro->r_notifier;
555 list_add_tail(&notifier->n_list,
556 &rs->rs_notify_queue);
557 if (!notifier->n_status)
558 notifier->n_status = status;
559 rm->m_rdma_op->r_notifier = NULL;
560 }
561 rds_message_put(rm);
562 rm->m_rs = NULL;
563 }
564
565unlock_and_drop:
566 spin_unlock(&rm->m_rs_lock);
567 rds_message_put(rm);
568 }
569
570 if (rs) {
571 spin_unlock(&rs->rs_lock);
572 rds_wake_sk_sleep(rs);
573 sock_put(rds_rs_to_sk(rs));
574 }
575 local_irq_restore(flags);
576}
577
578/*
579 * Transports call here when they've determined that the receiver queued
580 * messages up to, and including, the given sequence number. Messages are
581 * moved to the retrans queue when rds_send_xmit picks them off the send
582 * queue. This means that in the TCP case, the message may not have been
583 * assigned the m_ack_seq yet - but that's fine as long as tcp_is_acked
584 * checks the RDS_MSG_HAS_ACK_SEQ bit.
585 *
586 * XXX It's not clear to me how this is safely serialized with socket
587 * destruction. Maybe it should bail if it sees SOCK_DEAD.
588 */
589void rds_send_drop_acked(struct rds_connection *conn, u64 ack,
590 is_acked_func is_acked)
591{
592 struct rds_message *rm, *tmp;
593 unsigned long flags;
594 LIST_HEAD(list);
595
596 spin_lock_irqsave(&conn->c_lock, flags);
597
598 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
599 if (!rds_send_is_acked(rm, ack, is_acked))
600 break;
601
602 list_move(&rm->m_conn_item, &list);
603 clear_bit(RDS_MSG_ON_CONN, &rm->m_flags);
604 }
605
606 /* order flag updates with spin locks */
607 if (!list_empty(&list))
608 smp_mb__after_clear_bit();
609
610 spin_unlock_irqrestore(&conn->c_lock, flags);
611
612 /* now remove the messages from the sock list as needed */
613 rds_send_remove_from_sock(&list, RDS_RDMA_SUCCESS);
614}
Andy Grover616b7572009-08-21 12:28:32 +0000615EXPORT_SYMBOL_GPL(rds_send_drop_acked);
Andy Grover5c115592009-02-24 15:30:27 +0000616
617void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest)
618{
619 struct rds_message *rm, *tmp;
620 struct rds_connection *conn;
Andy Groverf1cffcb2009-04-01 08:20:18 +0000621 unsigned long flags, flags2;
Andy Grover5c115592009-02-24 15:30:27 +0000622 LIST_HEAD(list);
623 int wake = 0;
624
625 /* get all the messages we're dropping under the rs lock */
626 spin_lock_irqsave(&rs->rs_lock, flags);
627
628 list_for_each_entry_safe(rm, tmp, &rs->rs_send_queue, m_sock_item) {
629 if (dest && (dest->sin_addr.s_addr != rm->m_daddr ||
630 dest->sin_port != rm->m_inc.i_hdr.h_dport))
631 continue;
632
633 wake = 1;
634 list_move(&rm->m_sock_item, &list);
635 rds_send_sndbuf_remove(rs, rm);
636 clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
637
638 /* If this is a RDMA operation, notify the app. */
639 __rds_rdma_send_complete(rs, rm, RDS_RDMA_CANCELED);
640 }
641
642 /* order flag updates with the rs lock */
643 if (wake)
644 smp_mb__after_clear_bit();
645
646 spin_unlock_irqrestore(&rs->rs_lock, flags);
647
648 if (wake)
649 rds_wake_sk_sleep(rs);
650
651 conn = NULL;
652
653 /* now remove the messages from the conn list as needed */
654 list_for_each_entry(rm, &list, m_sock_item) {
655 /* We do this here rather than in the loop above, so that
656 * we don't have to nest m_rs_lock under rs->rs_lock */
Andy Groverf1cffcb2009-04-01 08:20:18 +0000657 spin_lock_irqsave(&rm->m_rs_lock, flags2);
Andy Grover5c115592009-02-24 15:30:27 +0000658 rm->m_rs = NULL;
Andy Groverf1cffcb2009-04-01 08:20:18 +0000659 spin_unlock_irqrestore(&rm->m_rs_lock, flags2);
Andy Grover5c115592009-02-24 15:30:27 +0000660
661 /*
662 * If we see this flag cleared then we're *sure* that someone
663 * else beat us to removing it from the conn. If we race
664 * with their flag update we'll get the lock and then really
665 * see that the flag has been cleared.
666 */
667 if (!test_bit(RDS_MSG_ON_CONN, &rm->m_flags))
668 continue;
669
670 if (conn != rm->m_inc.i_conn) {
671 if (conn)
672 spin_unlock_irqrestore(&conn->c_lock, flags);
673 conn = rm->m_inc.i_conn;
674 spin_lock_irqsave(&conn->c_lock, flags);
675 }
676
677 if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) {
678 list_del_init(&rm->m_conn_item);
679 rds_message_put(rm);
680 }
681 }
682
683 if (conn)
684 spin_unlock_irqrestore(&conn->c_lock, flags);
685
686 while (!list_empty(&list)) {
687 rm = list_entry(list.next, struct rds_message, m_sock_item);
688 list_del_init(&rm->m_sock_item);
689
690 rds_message_wait(rm);
691 rds_message_put(rm);
692 }
693}
694
695/*
696 * we only want this to fire once so we use the callers 'queued'. It's
697 * possible that another thread can race with us and remove the
698 * message from the flow with RDS_CANCEL_SENT_TO.
699 */
700static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn,
701 struct rds_message *rm, __be16 sport,
702 __be16 dport, int *queued)
703{
704 unsigned long flags;
705 u32 len;
706
707 if (*queued)
708 goto out;
709
710 len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
711
712 /* this is the only place which holds both the socket's rs_lock
713 * and the connection's c_lock */
714 spin_lock_irqsave(&rs->rs_lock, flags);
715
716 /*
717 * If there is a little space in sndbuf, we don't queue anything,
718 * and userspace gets -EAGAIN. But poll() indicates there's send
719 * room. This can lead to bad behavior (spinning) if snd_bytes isn't
720 * freed up by incoming acks. So we check the *old* value of
721 * rs_snd_bytes here to allow the last msg to exceed the buffer,
722 * and poll() now knows no more data can be sent.
723 */
724 if (rs->rs_snd_bytes < rds_sk_sndbuf(rs)) {
725 rs->rs_snd_bytes += len;
726
727 /* let recv side know we are close to send space exhaustion.
728 * This is probably not the optimal way to do it, as this
729 * means we set the flag on *all* messages as soon as our
730 * throughput hits a certain threshold.
731 */
732 if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2)
733 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
734
735 list_add_tail(&rm->m_sock_item, &rs->rs_send_queue);
736 set_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
737 rds_message_addref(rm);
738 rm->m_rs = rs;
739
740 /* The code ordering is a little weird, but we're
741 trying to minimize the time we hold c_lock */
742 rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport, 0);
743 rm->m_inc.i_conn = conn;
744 rds_message_addref(rm);
745
746 spin_lock(&conn->c_lock);
747 rm->m_inc.i_hdr.h_sequence = cpu_to_be64(conn->c_next_tx_seq++);
748 list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
749 set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
750 spin_unlock(&conn->c_lock);
751
752 rdsdebug("queued msg %p len %d, rs %p bytes %d seq %llu\n",
753 rm, len, rs, rs->rs_snd_bytes,
754 (unsigned long long)be64_to_cpu(rm->m_inc.i_hdr.h_sequence));
755
756 *queued = 1;
757 }
758
759 spin_unlock_irqrestore(&rs->rs_lock, flags);
760out:
761 return *queued;
762}
763
764static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
765 struct msghdr *msg, int *allocated_mr)
766{
767 struct cmsghdr *cmsg;
768 int ret = 0;
769
770 for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
771 if (!CMSG_OK(msg, cmsg))
772 return -EINVAL;
773
774 if (cmsg->cmsg_level != SOL_RDS)
775 continue;
776
777 /* As a side effect, RDMA_DEST and RDMA_MAP will set
778 * rm->m_rdma_cookie and rm->m_rdma_mr.
779 */
780 switch (cmsg->cmsg_type) {
781 case RDS_CMSG_RDMA_ARGS:
782 ret = rds_cmsg_rdma_args(rs, rm, cmsg);
783 break;
784
785 case RDS_CMSG_RDMA_DEST:
786 ret = rds_cmsg_rdma_dest(rs, rm, cmsg);
787 break;
788
789 case RDS_CMSG_RDMA_MAP:
790 ret = rds_cmsg_rdma_map(rs, rm, cmsg);
791 if (!ret)
792 *allocated_mr = 1;
793 break;
794
795 default:
796 return -EINVAL;
797 }
798
799 if (ret)
800 break;
801 }
802
803 return ret;
804}
805
806int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
807 size_t payload_len)
808{
809 struct sock *sk = sock->sk;
810 struct rds_sock *rs = rds_sk_to_rs(sk);
811 struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name;
812 __be32 daddr;
813 __be16 dport;
814 struct rds_message *rm = NULL;
815 struct rds_connection *conn;
816 int ret = 0;
817 int queued = 0, allocated_mr = 0;
818 int nonblock = msg->msg_flags & MSG_DONTWAIT;
819 long timeo = sock_rcvtimeo(sk, nonblock);
820
821 /* Mirror Linux UDP mirror of BSD error message compatibility */
822 /* XXX: Perhaps MSG_MORE someday */
823 if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) {
824 printk(KERN_INFO "msg_flags 0x%08X\n", msg->msg_flags);
825 ret = -EOPNOTSUPP;
826 goto out;
827 }
828
829 if (msg->msg_namelen) {
830 /* XXX fail non-unicast destination IPs? */
831 if (msg->msg_namelen < sizeof(*usin) || usin->sin_family != AF_INET) {
832 ret = -EINVAL;
833 goto out;
834 }
835 daddr = usin->sin_addr.s_addr;
836 dport = usin->sin_port;
837 } else {
838 /* We only care about consistency with ->connect() */
839 lock_sock(sk);
840 daddr = rs->rs_conn_addr;
841 dport = rs->rs_conn_port;
842 release_sock(sk);
843 }
844
845 /* racing with another thread binding seems ok here */
846 if (daddr == 0 || rs->rs_bound_addr == 0) {
847 ret = -ENOTCONN; /* XXX not a great errno */
848 goto out;
849 }
850
851 rm = rds_message_copy_from_user(msg->msg_iov, payload_len);
852 if (IS_ERR(rm)) {
853 ret = PTR_ERR(rm);
854 rm = NULL;
855 goto out;
856 }
857
858 rm->m_daddr = daddr;
859
Andy Grover5c115592009-02-24 15:30:27 +0000860 /* rds_conn_create has a spinlock that runs with IRQ off.
861 * Caching the conn in the socket helps a lot. */
862 if (rs->rs_conn && rs->rs_conn->c_faddr == daddr)
863 conn = rs->rs_conn;
864 else {
865 conn = rds_conn_create_outgoing(rs->rs_bound_addr, daddr,
866 rs->rs_transport,
867 sock->sk->sk_allocation);
868 if (IS_ERR(conn)) {
869 ret = PTR_ERR(conn);
870 goto out;
871 }
872 rs->rs_conn = conn;
873 }
874
Andy Grover49f69692009-04-09 14:09:41 +0000875 /* Parse any control messages the user may have included. */
876 ret = rds_cmsg_send(rs, rm, msg, &allocated_mr);
877 if (ret)
878 goto out;
879
Joe Perchesf64f9e72009-11-29 16:55:45 -0800880 if ((rm->m_rdma_cookie || rm->m_rdma_op) &&
881 conn->c_trans->xmit_rdma == NULL) {
Andy Grover5c115592009-02-24 15:30:27 +0000882 if (printk_ratelimit())
883 printk(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",
884 rm->m_rdma_op, conn->c_trans->xmit_rdma);
885 ret = -EOPNOTSUPP;
886 goto out;
887 }
888
889 /* If the connection is down, trigger a connect. We may
890 * have scheduled a delayed reconnect however - in this case
891 * we should not interfere.
892 */
Joe Perchesf64f9e72009-11-29 16:55:45 -0800893 if (rds_conn_state(conn) == RDS_CONN_DOWN &&
894 !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
Andy Grover5c115592009-02-24 15:30:27 +0000895 queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
896
897 ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);
898 if (ret)
899 goto out;
900
901 while (!rds_send_queue_rm(rs, conn, rm, rs->rs_bound_port,
902 dport, &queued)) {
903 rds_stats_inc(s_send_queue_full);
904 /* XXX make sure this is reasonable */
905 if (payload_len > rds_sk_sndbuf(rs)) {
906 ret = -EMSGSIZE;
907 goto out;
908 }
909 if (nonblock) {
910 ret = -EAGAIN;
911 goto out;
912 }
913
914 timeo = wait_event_interruptible_timeout(*sk->sk_sleep,
915 rds_send_queue_rm(rs, conn, rm,
916 rs->rs_bound_port,
917 dport,
918 &queued),
919 timeo);
920 rdsdebug("sendmsg woke queued %d timeo %ld\n", queued, timeo);
921 if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
922 continue;
923
924 ret = timeo;
925 if (ret == 0)
926 ret = -ETIMEDOUT;
927 goto out;
928 }
929
930 /*
931 * By now we've committed to the send. We reuse rds_send_worker()
932 * to retry sends in the rds thread if the transport asks us to.
933 */
934 rds_stats_inc(s_send_queued);
935
936 if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
937 rds_send_worker(&conn->c_send_w.work);
938
939 rds_message_put(rm);
940 return payload_len;
941
942out:
943 /* If the user included a RDMA_MAP cmsg, we allocated a MR on the fly.
944 * If the sendmsg goes through, we keep the MR. If it fails with EAGAIN
945 * or in any other way, we need to destroy the MR again */
946 if (allocated_mr)
947 rds_rdma_unuse(rs, rds_rdma_cookie_key(rm->m_rdma_cookie), 1);
948
949 if (rm)
950 rds_message_put(rm);
951 return ret;
952}
953
954/*
955 * Reply to a ping packet.
956 */
957int
958rds_send_pong(struct rds_connection *conn, __be16 dport)
959{
960 struct rds_message *rm;
961 unsigned long flags;
962 int ret = 0;
963
964 rm = rds_message_alloc(0, GFP_ATOMIC);
965 if (rm == NULL) {
966 ret = -ENOMEM;
967 goto out;
968 }
969
970 rm->m_daddr = conn->c_faddr;
971
972 /* If the connection is down, trigger a connect. We may
973 * have scheduled a delayed reconnect however - in this case
974 * we should not interfere.
975 */
Joe Perchesf64f9e72009-11-29 16:55:45 -0800976 if (rds_conn_state(conn) == RDS_CONN_DOWN &&
977 !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
Andy Grover5c115592009-02-24 15:30:27 +0000978 queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
979
980 ret = rds_cong_wait(conn->c_fcong, dport, 1, NULL);
981 if (ret)
982 goto out;
983
984 spin_lock_irqsave(&conn->c_lock, flags);
985 list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
986 set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
987 rds_message_addref(rm);
988 rm->m_inc.i_conn = conn;
989
990 rds_message_populate_header(&rm->m_inc.i_hdr, 0, dport,
991 conn->c_next_tx_seq);
992 conn->c_next_tx_seq++;
993 spin_unlock_irqrestore(&conn->c_lock, flags);
994
995 rds_stats_inc(s_send_queued);
996 rds_stats_inc(s_send_pong);
997
998 queue_delayed_work(rds_wq, &conn->c_send_w, 0);
999 rds_message_put(rm);
1000 return 0;
1001
1002out:
1003 if (rm)
1004 rds_message_put(rm);
1005 return ret;
1006}