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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{
Andy Grover561c7df2010-03-11 13:50:06 +0000511 unsigned long flags;
Andy Grover5c115592009-02-24 15:30:27 +0000512 struct rds_sock *rs = NULL;
513 struct rds_message *rm;
514
Andy Grover5c115592009-02-24 15:30:27 +0000515 while (!list_empty(messages)) {
Andy Grover561c7df2010-03-11 13:50:06 +0000516 int was_on_sock = 0;
517
Andy Grover5c115592009-02-24 15:30:27 +0000518 rm = list_entry(messages->next, struct rds_message,
519 m_conn_item);
520 list_del_init(&rm->m_conn_item);
521
522 /*
523 * If we see this flag cleared then we're *sure* that someone
524 * else beat us to removing it from the sock. If we race
525 * with their flag update we'll get the lock and then really
526 * see that the flag has been cleared.
527 *
528 * The message spinlock makes sure nobody clears rm->m_rs
529 * while we're messing with it. It does not prevent the
530 * message from being removed from the socket, though.
531 */
Andy Grover561c7df2010-03-11 13:50:06 +0000532 spin_lock_irqsave(&rm->m_rs_lock, flags);
Andy Grover5c115592009-02-24 15:30:27 +0000533 if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags))
534 goto unlock_and_drop;
535
536 if (rs != rm->m_rs) {
537 if (rs) {
Andy Grover5c115592009-02-24 15:30:27 +0000538 rds_wake_sk_sleep(rs);
539 sock_put(rds_rs_to_sk(rs));
540 }
541 rs = rm->m_rs;
Andy Grover5c115592009-02-24 15:30:27 +0000542 sock_hold(rds_rs_to_sk(rs));
543 }
Tina Yang048c15e2010-03-11 13:50:00 +0000544 spin_lock(&rs->rs_lock);
Andy Grover5c115592009-02-24 15:30:27 +0000545
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 }
Andy Grover561c7df2010-03-11 13:50:06 +0000561 was_on_sock = 1;
Andy Grover5c115592009-02-24 15:30:27 +0000562 rm->m_rs = NULL;
563 }
Tina Yang048c15e2010-03-11 13:50:00 +0000564 spin_unlock(&rs->rs_lock);
Andy Grover5c115592009-02-24 15:30:27 +0000565
566unlock_and_drop:
Andy Grover561c7df2010-03-11 13:50:06 +0000567 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
Andy Grover5c115592009-02-24 15:30:27 +0000568 rds_message_put(rm);
Andy Grover561c7df2010-03-11 13:50:06 +0000569 if (was_on_sock)
570 rds_message_put(rm);
Andy Grover5c115592009-02-24 15:30:27 +0000571 }
572
573 if (rs) {
Andy Grover5c115592009-02-24 15:30:27 +0000574 rds_wake_sk_sleep(rs);
575 sock_put(rds_rs_to_sk(rs));
576 }
Andy Grover5c115592009-02-24 15:30:27 +0000577}
578
579/*
580 * Transports call here when they've determined that the receiver queued
581 * messages up to, and including, the given sequence number. Messages are
582 * moved to the retrans queue when rds_send_xmit picks them off the send
583 * queue. This means that in the TCP case, the message may not have been
584 * assigned the m_ack_seq yet - but that's fine as long as tcp_is_acked
585 * checks the RDS_MSG_HAS_ACK_SEQ bit.
586 *
587 * XXX It's not clear to me how this is safely serialized with socket
588 * destruction. Maybe it should bail if it sees SOCK_DEAD.
589 */
590void rds_send_drop_acked(struct rds_connection *conn, u64 ack,
591 is_acked_func is_acked)
592{
593 struct rds_message *rm, *tmp;
594 unsigned long flags;
595 LIST_HEAD(list);
596
597 spin_lock_irqsave(&conn->c_lock, flags);
598
599 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
600 if (!rds_send_is_acked(rm, ack, is_acked))
601 break;
602
603 list_move(&rm->m_conn_item, &list);
604 clear_bit(RDS_MSG_ON_CONN, &rm->m_flags);
605 }
606
607 /* order flag updates with spin locks */
608 if (!list_empty(&list))
609 smp_mb__after_clear_bit();
610
611 spin_unlock_irqrestore(&conn->c_lock, flags);
612
613 /* now remove the messages from the sock list as needed */
614 rds_send_remove_from_sock(&list, RDS_RDMA_SUCCESS);
615}
Andy Grover616b7572009-08-21 12:28:32 +0000616EXPORT_SYMBOL_GPL(rds_send_drop_acked);
Andy Grover5c115592009-02-24 15:30:27 +0000617
618void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest)
619{
620 struct rds_message *rm, *tmp;
621 struct rds_connection *conn;
Andy Groverf1cffcb2009-04-01 08:20:18 +0000622 unsigned long flags, flags2;
Andy Grover5c115592009-02-24 15:30:27 +0000623 LIST_HEAD(list);
624 int wake = 0;
625
626 /* get all the messages we're dropping under the rs lock */
627 spin_lock_irqsave(&rs->rs_lock, flags);
628
629 list_for_each_entry_safe(rm, tmp, &rs->rs_send_queue, m_sock_item) {
630 if (dest && (dest->sin_addr.s_addr != rm->m_daddr ||
631 dest->sin_port != rm->m_inc.i_hdr.h_dport))
632 continue;
633
634 wake = 1;
635 list_move(&rm->m_sock_item, &list);
636 rds_send_sndbuf_remove(rs, rm);
637 clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
Andy Grover5c115592009-02-24 15:30:27 +0000638 }
639
640 /* order flag updates with the rs lock */
641 if (wake)
642 smp_mb__after_clear_bit();
643
644 spin_unlock_irqrestore(&rs->rs_lock, flags);
645
Andy Grover5c115592009-02-24 15:30:27 +0000646 conn = NULL;
647
648 /* now remove the messages from the conn list as needed */
649 list_for_each_entry(rm, &list, m_sock_item) {
650 /* We do this here rather than in the loop above, so that
651 * we don't have to nest m_rs_lock under rs->rs_lock */
Andy Groverf1cffcb2009-04-01 08:20:18 +0000652 spin_lock_irqsave(&rm->m_rs_lock, flags2);
Tina Yang550a8002010-03-11 13:50:03 +0000653 /* If this is a RDMA operation, notify the app. */
654 spin_lock(&rs->rs_lock);
655 __rds_rdma_send_complete(rs, rm, RDS_RDMA_CANCELED);
656 spin_unlock(&rs->rs_lock);
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
Tina Yang550a8002010-03-11 13:50:03 +0000685 if (wake)
686 rds_wake_sk_sleep(rs);
687
Andy Grover5c115592009-02-24 15:30:27 +0000688 while (!list_empty(&list)) {
689 rm = list_entry(list.next, struct rds_message, m_sock_item);
690 list_del_init(&rm->m_sock_item);
691
692 rds_message_wait(rm);
693 rds_message_put(rm);
694 }
695}
696
697/*
698 * we only want this to fire once so we use the callers 'queued'. It's
699 * possible that another thread can race with us and remove the
700 * message from the flow with RDS_CANCEL_SENT_TO.
701 */
702static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn,
703 struct rds_message *rm, __be16 sport,
704 __be16 dport, int *queued)
705{
706 unsigned long flags;
707 u32 len;
708
709 if (*queued)
710 goto out;
711
712 len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
713
714 /* this is the only place which holds both the socket's rs_lock
715 * and the connection's c_lock */
716 spin_lock_irqsave(&rs->rs_lock, flags);
717
718 /*
719 * If there is a little space in sndbuf, we don't queue anything,
720 * and userspace gets -EAGAIN. But poll() indicates there's send
721 * room. This can lead to bad behavior (spinning) if snd_bytes isn't
722 * freed up by incoming acks. So we check the *old* value of
723 * rs_snd_bytes here to allow the last msg to exceed the buffer,
724 * and poll() now knows no more data can be sent.
725 */
726 if (rs->rs_snd_bytes < rds_sk_sndbuf(rs)) {
727 rs->rs_snd_bytes += len;
728
729 /* let recv side know we are close to send space exhaustion.
730 * This is probably not the optimal way to do it, as this
731 * means we set the flag on *all* messages as soon as our
732 * throughput hits a certain threshold.
733 */
734 if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2)
735 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
736
737 list_add_tail(&rm->m_sock_item, &rs->rs_send_queue);
738 set_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
739 rds_message_addref(rm);
740 rm->m_rs = rs;
741
742 /* The code ordering is a little weird, but we're
743 trying to minimize the time we hold c_lock */
744 rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport, 0);
745 rm->m_inc.i_conn = conn;
746 rds_message_addref(rm);
747
748 spin_lock(&conn->c_lock);
749 rm->m_inc.i_hdr.h_sequence = cpu_to_be64(conn->c_next_tx_seq++);
750 list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
751 set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
752 spin_unlock(&conn->c_lock);
753
754 rdsdebug("queued msg %p len %d, rs %p bytes %d seq %llu\n",
755 rm, len, rs, rs->rs_snd_bytes,
756 (unsigned long long)be64_to_cpu(rm->m_inc.i_hdr.h_sequence));
757
758 *queued = 1;
759 }
760
761 spin_unlock_irqrestore(&rs->rs_lock, flags);
762out:
763 return *queued;
764}
765
766static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
767 struct msghdr *msg, int *allocated_mr)
768{
769 struct cmsghdr *cmsg;
770 int ret = 0;
771
772 for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
773 if (!CMSG_OK(msg, cmsg))
774 return -EINVAL;
775
776 if (cmsg->cmsg_level != SOL_RDS)
777 continue;
778
779 /* As a side effect, RDMA_DEST and RDMA_MAP will set
780 * rm->m_rdma_cookie and rm->m_rdma_mr.
781 */
782 switch (cmsg->cmsg_type) {
783 case RDS_CMSG_RDMA_ARGS:
784 ret = rds_cmsg_rdma_args(rs, rm, cmsg);
785 break;
786
787 case RDS_CMSG_RDMA_DEST:
788 ret = rds_cmsg_rdma_dest(rs, rm, cmsg);
789 break;
790
791 case RDS_CMSG_RDMA_MAP:
792 ret = rds_cmsg_rdma_map(rs, rm, cmsg);
793 if (!ret)
794 *allocated_mr = 1;
795 break;
796
797 default:
798 return -EINVAL;
799 }
800
801 if (ret)
802 break;
803 }
804
805 return ret;
806}
807
808int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
809 size_t payload_len)
810{
811 struct sock *sk = sock->sk;
812 struct rds_sock *rs = rds_sk_to_rs(sk);
813 struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name;
814 __be32 daddr;
815 __be16 dport;
816 struct rds_message *rm = NULL;
817 struct rds_connection *conn;
818 int ret = 0;
819 int queued = 0, allocated_mr = 0;
820 int nonblock = msg->msg_flags & MSG_DONTWAIT;
Andy Grover1123fd72010-03-11 13:49:56 +0000821 long timeo = sock_sndtimeo(sk, nonblock);
Andy Grover5c115592009-02-24 15:30:27 +0000822
823 /* Mirror Linux UDP mirror of BSD error message compatibility */
824 /* XXX: Perhaps MSG_MORE someday */
825 if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) {
826 printk(KERN_INFO "msg_flags 0x%08X\n", msg->msg_flags);
827 ret = -EOPNOTSUPP;
828 goto out;
829 }
830
831 if (msg->msg_namelen) {
832 /* XXX fail non-unicast destination IPs? */
833 if (msg->msg_namelen < sizeof(*usin) || usin->sin_family != AF_INET) {
834 ret = -EINVAL;
835 goto out;
836 }
837 daddr = usin->sin_addr.s_addr;
838 dport = usin->sin_port;
839 } else {
840 /* We only care about consistency with ->connect() */
841 lock_sock(sk);
842 daddr = rs->rs_conn_addr;
843 dport = rs->rs_conn_port;
844 release_sock(sk);
845 }
846
847 /* racing with another thread binding seems ok here */
848 if (daddr == 0 || rs->rs_bound_addr == 0) {
849 ret = -ENOTCONN; /* XXX not a great errno */
850 goto out;
851 }
852
853 rm = rds_message_copy_from_user(msg->msg_iov, payload_len);
854 if (IS_ERR(rm)) {
855 ret = PTR_ERR(rm);
856 rm = NULL;
857 goto out;
858 }
859
860 rm->m_daddr = daddr;
861
Andy Grover5c115592009-02-24 15:30:27 +0000862 /* 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
Andy Grover49f69692009-04-09 14:09:41 +0000877 /* Parse any control messages the user may have included. */
878 ret = rds_cmsg_send(rs, rm, msg, &allocated_mr);
879 if (ret)
880 goto out;
881
Joe Perchesf64f9e72009-11-29 16:55:45 -0800882 if ((rm->m_rdma_cookie || rm->m_rdma_op) &&
883 conn->c_trans->xmit_rdma == NULL) {
Andy Grover5c115592009-02-24 15:30:27 +0000884 if (printk_ratelimit())
885 printk(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",
886 rm->m_rdma_op, conn->c_trans->xmit_rdma);
887 ret = -EOPNOTSUPP;
888 goto out;
889 }
890
891 /* If the connection is down, trigger a connect. We may
892 * have scheduled a delayed reconnect however - in this case
893 * we should not interfere.
894 */
Joe Perchesf64f9e72009-11-29 16:55:45 -0800895 if (rds_conn_state(conn) == RDS_CONN_DOWN &&
896 !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
Andy Grover5c115592009-02-24 15:30:27 +0000897 queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
898
899 ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);
Andy Groverb98ba522010-03-11 13:50:04 +0000900 if (ret) {
901 rs->rs_seen_congestion = 1;
Andy Grover5c115592009-02-24 15:30:27 +0000902 goto out;
Andy Groverb98ba522010-03-11 13:50:04 +0000903 }
Andy Grover5c115592009-02-24 15:30:27 +0000904
905 while (!rds_send_queue_rm(rs, conn, rm, rs->rs_bound_port,
906 dport, &queued)) {
907 rds_stats_inc(s_send_queue_full);
908 /* XXX make sure this is reasonable */
909 if (payload_len > rds_sk_sndbuf(rs)) {
910 ret = -EMSGSIZE;
911 goto out;
912 }
913 if (nonblock) {
914 ret = -EAGAIN;
915 goto out;
916 }
917
Eric Dumazetaa395142010-04-20 13:03:51 +0000918 timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
Andy Grover5c115592009-02-24 15:30:27 +0000919 rds_send_queue_rm(rs, conn, rm,
920 rs->rs_bound_port,
921 dport,
922 &queued),
923 timeo);
924 rdsdebug("sendmsg woke queued %d timeo %ld\n", queued, timeo);
925 if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
926 continue;
927
928 ret = timeo;
929 if (ret == 0)
930 ret = -ETIMEDOUT;
931 goto out;
932 }
933
934 /*
935 * By now we've committed to the send. We reuse rds_send_worker()
936 * to retry sends in the rds thread if the transport asks us to.
937 */
938 rds_stats_inc(s_send_queued);
939
940 if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
941 rds_send_worker(&conn->c_send_w.work);
942
943 rds_message_put(rm);
944 return payload_len;
945
946out:
947 /* If the user included a RDMA_MAP cmsg, we allocated a MR on the fly.
948 * If the sendmsg goes through, we keep the MR. If it fails with EAGAIN
949 * or in any other way, we need to destroy the MR again */
950 if (allocated_mr)
951 rds_rdma_unuse(rs, rds_rdma_cookie_key(rm->m_rdma_cookie), 1);
952
953 if (rm)
954 rds_message_put(rm);
955 return ret;
956}
957
958/*
959 * Reply to a ping packet.
960 */
961int
962rds_send_pong(struct rds_connection *conn, __be16 dport)
963{
964 struct rds_message *rm;
965 unsigned long flags;
966 int ret = 0;
967
968 rm = rds_message_alloc(0, GFP_ATOMIC);
969 if (rm == NULL) {
970 ret = -ENOMEM;
971 goto out;
972 }
973
974 rm->m_daddr = conn->c_faddr;
975
976 /* If the connection is down, trigger a connect. We may
977 * have scheduled a delayed reconnect however - in this case
978 * we should not interfere.
979 */
Joe Perchesf64f9e72009-11-29 16:55:45 -0800980 if (rds_conn_state(conn) == RDS_CONN_DOWN &&
981 !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
Andy Grover5c115592009-02-24 15:30:27 +0000982 queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
983
984 ret = rds_cong_wait(conn->c_fcong, dport, 1, NULL);
985 if (ret)
986 goto out;
987
988 spin_lock_irqsave(&conn->c_lock, flags);
989 list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
990 set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
991 rds_message_addref(rm);
992 rm->m_inc.i_conn = conn;
993
994 rds_message_populate_header(&rm->m_inc.i_hdr, 0, dport,
995 conn->c_next_tx_seq);
996 conn->c_next_tx_seq++;
997 spin_unlock_irqrestore(&conn->c_lock, flags);
998
999 rds_stats_inc(s_send_queued);
1000 rds_stats_inc(s_send_pong);
1001
1002 queue_delayed_work(rds_wq, &conn->c_send_w, 0);
1003 rds_message_put(rm);
1004 return 0;
1005
1006out:
1007 if (rm)
1008 rds_message_put(rm);
1009 return ret;
1010}