blob: d60d31309032903cf0765570af6d0ca070fafca4 [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>
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"
Andy Grover5c115592009-02-24 15:30:27 +000040
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;
Andy Grover15133f62010-01-12 14:33:38 -080076 conn->c_xmit_atomic_sent = 0;
Andy Grover5c115592009-02-24 15:30:27 +000077
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,
Andy Grover6200ed72010-01-12 10:53:05 -0800153 conn->c_map_offset);
Andy Grover5c115592009-02-24 15:30:27 +0000154 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;
Andy Grover8690bfa2010-01-12 11:56:44 -0800167 if (rm &&
Andy Grover5c115592009-02-24 15:30:27 +0000168 conn->c_xmit_hdr_off == sizeof(struct rds_header) &&
Andy Grover6c7cc6e2010-01-27 18:04:18 -0800169 conn->c_xmit_sg == rm->data.op_nents) {
Andy Grover5c115592009-02-24 15:30:27 +0000170 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;
Andy Grover15133f62010-01-12 14:33:38 -0800175 conn->c_xmit_atomic_sent = 0;
Andy Grover5c115592009-02-24 15:30:27 +0000176
177 /* Release the reference to the previous message. */
178 rds_message_put(rm);
179 rm = NULL;
180 }
181
182 /* If we're asked to send a cong map update, do so.
183 */
Andy Grover8690bfa2010-01-12 11:56:44 -0800184 if (!rm && test_and_clear_bit(0, &conn->c_map_queued)) {
185 if (conn->c_trans->xmit_cong_map) {
Andy Grover5c115592009-02-24 15:30:27 +0000186 conn->c_map_offset = 0;
187 conn->c_map_bytes = sizeof(struct rds_header) +
188 RDS_CONG_MAP_BYTES;
189 continue;
190 }
191
192 rm = rds_cong_update_alloc(conn);
193 if (IS_ERR(rm)) {
194 ret = PTR_ERR(rm);
195 break;
196 }
197
198 conn->c_xmit_rm = rm;
199 }
200
201 /*
202 * Grab the next message from the send queue, if there is one.
203 *
204 * c_xmit_rm holds a ref while we're sending this message down
205 * the connction. We can use this ref while holding the
206 * send_sem.. rds_send_reset() is serialized with it.
207 */
Andy Grover8690bfa2010-01-12 11:56:44 -0800208 if (!rm) {
Andy Grover5c115592009-02-24 15:30:27 +0000209 unsigned int len;
210
211 spin_lock_irqsave(&conn->c_lock, flags);
212
213 if (!list_empty(&conn->c_send_queue)) {
214 rm = list_entry(conn->c_send_queue.next,
215 struct rds_message,
216 m_conn_item);
217 rds_message_addref(rm);
218
219 /*
220 * Move the message from the send queue to the retransmit
221 * list right away.
222 */
223 list_move_tail(&rm->m_conn_item, &conn->c_retrans);
224 }
225
226 spin_unlock_irqrestore(&conn->c_lock, flags);
227
Andy Grover8690bfa2010-01-12 11:56:44 -0800228 if (!rm) {
Andy Grover5c115592009-02-24 15:30:27 +0000229 was_empty = 1;
230 break;
231 }
232
233 /* Unfortunately, the way Infiniband deals with
234 * RDMA to a bad MR key is by moving the entire
235 * queue pair to error state. We cold possibly
236 * recover from that, but right now we drop the
237 * connection.
238 * Therefore, we never retransmit messages with RDMA ops.
239 */
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800240 if (rm->rdma.op_active &&
Joe Perchesf64f9e72009-11-29 16:55:45 -0800241 test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) {
Andy Grover5c115592009-02-24 15:30:27 +0000242 spin_lock_irqsave(&conn->c_lock, flags);
243 if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags))
244 list_move(&rm->m_conn_item, &to_be_dropped);
245 spin_unlock_irqrestore(&conn->c_lock, flags);
246 rds_message_put(rm);
247 continue;
248 }
249
250 /* Require an ACK every once in a while */
251 len = ntohl(rm->m_inc.i_hdr.h_len);
Joe Perchesf64f9e72009-11-29 16:55:45 -0800252 if (conn->c_unacked_packets == 0 ||
253 conn->c_unacked_bytes < len) {
Andy Grover5c115592009-02-24 15:30:27 +0000254 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
255
256 conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
257 conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
258 rds_stats_inc(s_send_ack_required);
259 } else {
260 conn->c_unacked_bytes -= len;
261 conn->c_unacked_packets--;
262 }
263
264 conn->c_xmit_rm = rm;
265 }
266
Andy Grover15133f62010-01-12 14:33:38 -0800267
268 if (rm->atomic.op_active && !conn->c_xmit_atomic_sent) {
Andy Grover241eef32010-01-19 21:25:26 -0800269 ret = conn->c_trans->xmit_atomic(conn, rm);
Andy Grover15133f62010-01-12 14:33:38 -0800270 if (ret)
271 break;
272 conn->c_xmit_atomic_sent = 1;
273 /* The transport owns the mapped memory for now.
274 * You can't unmap it while it's on the send queue */
275 set_bit(RDS_MSG_MAPPED, &rm->m_flags);
276 }
277
Andy Grover5c115592009-02-24 15:30:27 +0000278 /*
279 * Try and send an rdma message. Let's see if we can
280 * keep this simple and require that the transport either
281 * send the whole rdma or none of it.
282 */
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800283 if (rm->rdma.op_active && !conn->c_xmit_rdma_sent) {
284 ret = conn->c_trans->xmit_rdma(conn, &rm->rdma);
Andy Grover5c115592009-02-24 15:30:27 +0000285 if (ret)
286 break;
287 conn->c_xmit_rdma_sent = 1;
Andy Grover241eef32010-01-19 21:25:26 -0800288
289 /* rdmas need data sent, even if just the header */
290 rm->data.op_active = 1;
291
Andy Grover5c115592009-02-24 15:30:27 +0000292 /* The transport owns the mapped memory for now.
293 * You can't unmap it while it's on the send queue */
294 set_bit(RDS_MSG_MAPPED, &rm->m_flags);
295 }
296
Andy Grover241eef32010-01-19 21:25:26 -0800297 if (rm->data.op_active
298 && (conn->c_xmit_hdr_off < sizeof(struct rds_header) ||
Andy Grover6c7cc6e2010-01-27 18:04:18 -0800299 conn->c_xmit_sg < rm->data.op_nents)) {
Andy Grover5c115592009-02-24 15:30:27 +0000300 ret = conn->c_trans->xmit(conn, rm,
301 conn->c_xmit_hdr_off,
302 conn->c_xmit_sg,
303 conn->c_xmit_data_off);
304 if (ret <= 0)
305 break;
306
307 if (conn->c_xmit_hdr_off < sizeof(struct rds_header)) {
308 tmp = min_t(int, ret,
309 sizeof(struct rds_header) -
310 conn->c_xmit_hdr_off);
311 conn->c_xmit_hdr_off += tmp;
312 ret -= tmp;
313 }
314
Andy Grover6c7cc6e2010-01-27 18:04:18 -0800315 sg = &rm->data.op_sg[conn->c_xmit_sg];
Andy Grover5c115592009-02-24 15:30:27 +0000316 while (ret) {
317 tmp = min_t(int, ret, sg->length -
318 conn->c_xmit_data_off);
319 conn->c_xmit_data_off += tmp;
320 ret -= tmp;
321 if (conn->c_xmit_data_off == sg->length) {
322 conn->c_xmit_data_off = 0;
323 sg++;
324 conn->c_xmit_sg++;
325 BUG_ON(ret != 0 &&
Andy Grover6c7cc6e2010-01-27 18:04:18 -0800326 conn->c_xmit_sg == rm->data.op_nents);
Andy Grover5c115592009-02-24 15:30:27 +0000327 }
328 }
329 }
330 }
331
332 /* Nuke any messages we decided not to retransmit. */
333 if (!list_empty(&to_be_dropped))
334 rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED);
335
336 if (conn->c_trans->xmit_complete)
337 conn->c_trans->xmit_complete(conn);
338
339 /*
340 * We might be racing with another sender who queued a message but
341 * backed off on noticing that we held the c_send_lock. If we check
342 * for queued messages after dropping the sem then either we'll
343 * see the queued message or the queuer will get the sem. If we
344 * notice the queued message then we trigger an immediate retry.
345 *
346 * We need to be careful only to do this when we stopped processing
347 * the send queue because it was empty. It's the only way we
348 * stop processing the loop when the transport hasn't taken
349 * responsibility for forward progress.
350 */
351 mutex_unlock(&conn->c_send_lock);
352
353 if (conn->c_map_bytes || (send_quota == 0 && !was_empty)) {
354 /* We exhausted the send quota, but there's work left to
355 * do. Return and (re-)schedule the send worker.
356 */
357 ret = -EAGAIN;
358 }
359
360 if (ret == 0 && was_empty) {
361 /* A simple bit test would be way faster than taking the
362 * spin lock */
363 spin_lock_irqsave(&conn->c_lock, flags);
364 if (!list_empty(&conn->c_send_queue)) {
365 rds_stats_inc(s_send_sem_queue_raced);
366 ret = -EAGAIN;
367 }
368 spin_unlock_irqrestore(&conn->c_lock, flags);
369 }
370out:
371 return ret;
372}
373
374static void rds_send_sndbuf_remove(struct rds_sock *rs, struct rds_message *rm)
375{
376 u32 len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
377
378 assert_spin_locked(&rs->rs_lock);
379
380 BUG_ON(rs->rs_snd_bytes < len);
381 rs->rs_snd_bytes -= len;
382
383 if (rs->rs_snd_bytes == 0)
384 rds_stats_inc(s_send_queue_empty);
385}
386
387static inline int rds_send_is_acked(struct rds_message *rm, u64 ack,
388 is_acked_func is_acked)
389{
390 if (is_acked)
391 return is_acked(rm, ack);
392 return be64_to_cpu(rm->m_inc.i_hdr.h_sequence) <= ack;
393}
394
395/*
396 * Returns true if there are no messages on the send and retransmit queues
397 * which have a sequence number greater than or equal to the given sequence
398 * number.
399 */
400int rds_send_acked_before(struct rds_connection *conn, u64 seq)
401{
402 struct rds_message *rm, *tmp;
403 int ret = 1;
404
405 spin_lock(&conn->c_lock);
406
407 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
408 if (be64_to_cpu(rm->m_inc.i_hdr.h_sequence) < seq)
409 ret = 0;
410 break;
411 }
412
413 list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
414 if (be64_to_cpu(rm->m_inc.i_hdr.h_sequence) < seq)
415 ret = 0;
416 break;
417 }
418
419 spin_unlock(&conn->c_lock);
420
421 return ret;
422}
423
424/*
425 * This is pretty similar to what happens below in the ACK
426 * handling code - except that we call here as soon as we get
427 * the IB send completion on the RDMA op and the accompanying
428 * message.
429 */
430void rds_rdma_send_complete(struct rds_message *rm, int status)
431{
432 struct rds_sock *rs = NULL;
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800433 struct rm_rdma_op *ro;
Andy Grover5c115592009-02-24 15:30:27 +0000434 struct rds_notifier *notifier;
Andy Grover9de08642010-03-29 16:50:54 -0700435 unsigned long flags;
Andy Grover5c115592009-02-24 15:30:27 +0000436
Andy Grover9de08642010-03-29 16:50:54 -0700437 spin_lock_irqsave(&rm->m_rs_lock, flags);
Andy Grover5c115592009-02-24 15:30:27 +0000438
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800439 ro = &rm->rdma;
Joe Perchesf64f9e72009-11-29 16:55:45 -0800440 if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) &&
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800441 ro->op_active && ro->op_notify && ro->op_notifier) {
442 notifier = ro->op_notifier;
Andy Grover5c115592009-02-24 15:30:27 +0000443 rs = rm->m_rs;
444 sock_hold(rds_rs_to_sk(rs));
445
446 notifier->n_status = status;
447 spin_lock(&rs->rs_lock);
448 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
449 spin_unlock(&rs->rs_lock);
450
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800451 ro->op_notifier = NULL;
Andy Grover5c115592009-02-24 15:30:27 +0000452 }
453
Andy Grover9de08642010-03-29 16:50:54 -0700454 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
Andy Grover5c115592009-02-24 15:30:27 +0000455
456 if (rs) {
457 rds_wake_sk_sleep(rs);
458 sock_put(rds_rs_to_sk(rs));
459 }
460}
Andy Grover616b7572009-08-21 12:28:32 +0000461EXPORT_SYMBOL_GPL(rds_rdma_send_complete);
Andy Grover5c115592009-02-24 15:30:27 +0000462
463/*
Andy Grover15133f62010-01-12 14:33:38 -0800464 * Just like above, except looks at atomic op
465 */
466void rds_atomic_send_complete(struct rds_message *rm, int status)
467{
468 struct rds_sock *rs = NULL;
469 struct rm_atomic_op *ao;
470 struct rds_notifier *notifier;
471
472 spin_lock(&rm->m_rs_lock);
473
474 ao = &rm->atomic;
475 if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags)
476 && ao->op_active && ao->op_notify && ao->op_notifier) {
477 notifier = ao->op_notifier;
478 rs = rm->m_rs;
479 sock_hold(rds_rs_to_sk(rs));
480
481 notifier->n_status = status;
482 spin_lock(&rs->rs_lock);
483 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
484 spin_unlock(&rs->rs_lock);
485
486 ao->op_notifier = NULL;
487 }
488
489 spin_unlock(&rm->m_rs_lock);
490
491 if (rs) {
492 rds_wake_sk_sleep(rs);
493 sock_put(rds_rs_to_sk(rs));
494 }
495}
496EXPORT_SYMBOL_GPL(rds_atomic_send_complete);
497
498/*
Andy Grover5c115592009-02-24 15:30:27 +0000499 * This is the same as rds_rdma_send_complete except we
500 * don't do any locking - we have all the ingredients (message,
501 * socket, socket lock) and can just move the notifier.
502 */
503static inline void
504__rds_rdma_send_complete(struct rds_sock *rs, struct rds_message *rm, int status)
505{
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800506 struct rm_rdma_op *ro;
Andy Grover5c115592009-02-24 15:30:27 +0000507
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800508 ro = &rm->rdma;
509 if (ro->op_active && ro->op_notify && ro->op_notifier) {
510 ro->op_notifier->n_status = status;
511 list_add_tail(&ro->op_notifier->n_list, &rs->rs_notify_queue);
512 ro->op_notifier = NULL;
Andy Grover5c115592009-02-24 15:30:27 +0000513 }
514
515 /* No need to wake the app - caller does this */
516}
517
518/*
519 * This is called from the IB send completion when we detect
520 * a RDMA operation that failed with remote access error.
521 * So speed is not an issue here.
522 */
523struct rds_message *rds_send_get_message(struct rds_connection *conn,
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800524 struct rm_rdma_op *op)
Andy Grover5c115592009-02-24 15:30:27 +0000525{
526 struct rds_message *rm, *tmp, *found = NULL;
527 unsigned long flags;
528
529 spin_lock_irqsave(&conn->c_lock, flags);
530
531 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800532 if (&rm->rdma == op) {
Andy Grover5c115592009-02-24 15:30:27 +0000533 atomic_inc(&rm->m_refcount);
534 found = rm;
535 goto out;
536 }
537 }
538
539 list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800540 if (&rm->rdma == op) {
Andy Grover5c115592009-02-24 15:30:27 +0000541 atomic_inc(&rm->m_refcount);
542 found = rm;
543 break;
544 }
545 }
546
547out:
548 spin_unlock_irqrestore(&conn->c_lock, flags);
549
550 return found;
551}
Andy Grover616b7572009-08-21 12:28:32 +0000552EXPORT_SYMBOL_GPL(rds_send_get_message);
Andy Grover5c115592009-02-24 15:30:27 +0000553
554/*
555 * This removes messages from the socket's list if they're on it. The list
556 * argument must be private to the caller, we must be able to modify it
557 * without locks. The messages must have a reference held for their
558 * position on the list. This function will drop that reference after
559 * removing the messages from the 'messages' list regardless of if it found
560 * the messages on the socket list or not.
561 */
562void rds_send_remove_from_sock(struct list_head *messages, int status)
563{
Andy Grover561c7df2010-03-11 13:50:06 +0000564 unsigned long flags;
Andy Grover5c115592009-02-24 15:30:27 +0000565 struct rds_sock *rs = NULL;
566 struct rds_message *rm;
567
Andy Grover5c115592009-02-24 15:30:27 +0000568 while (!list_empty(messages)) {
Andy Grover561c7df2010-03-11 13:50:06 +0000569 int was_on_sock = 0;
570
Andy Grover5c115592009-02-24 15:30:27 +0000571 rm = list_entry(messages->next, struct rds_message,
572 m_conn_item);
573 list_del_init(&rm->m_conn_item);
574
575 /*
576 * If we see this flag cleared then we're *sure* that someone
577 * else beat us to removing it from the sock. If we race
578 * with their flag update we'll get the lock and then really
579 * see that the flag has been cleared.
580 *
581 * The message spinlock makes sure nobody clears rm->m_rs
582 * while we're messing with it. It does not prevent the
583 * message from being removed from the socket, though.
584 */
Andy Grover561c7df2010-03-11 13:50:06 +0000585 spin_lock_irqsave(&rm->m_rs_lock, flags);
Andy Grover5c115592009-02-24 15:30:27 +0000586 if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags))
587 goto unlock_and_drop;
588
589 if (rs != rm->m_rs) {
590 if (rs) {
Andy Grover5c115592009-02-24 15:30:27 +0000591 rds_wake_sk_sleep(rs);
592 sock_put(rds_rs_to_sk(rs));
593 }
594 rs = rm->m_rs;
Andy Grover5c115592009-02-24 15:30:27 +0000595 sock_hold(rds_rs_to_sk(rs));
596 }
Tina Yang048c15e2010-03-11 13:50:00 +0000597 spin_lock(&rs->rs_lock);
Andy Grover5c115592009-02-24 15:30:27 +0000598
599 if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) {
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800600 struct rm_rdma_op *ro = &rm->rdma;
Andy Grover5c115592009-02-24 15:30:27 +0000601 struct rds_notifier *notifier;
602
603 list_del_init(&rm->m_sock_item);
604 rds_send_sndbuf_remove(rs, rm);
605
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800606 if (ro->op_active && ro->op_notifier &&
607 (ro->op_notify || (ro->op_recverr && status))) {
608 notifier = ro->op_notifier;
Andy Grover5c115592009-02-24 15:30:27 +0000609 list_add_tail(&notifier->n_list,
610 &rs->rs_notify_queue);
611 if (!notifier->n_status)
612 notifier->n_status = status;
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800613 rm->rdma.op_notifier = NULL;
Andy Grover5c115592009-02-24 15:30:27 +0000614 }
Andy Grover561c7df2010-03-11 13:50:06 +0000615 was_on_sock = 1;
Andy Grover5c115592009-02-24 15:30:27 +0000616 rm->m_rs = NULL;
617 }
Tina Yang048c15e2010-03-11 13:50:00 +0000618 spin_unlock(&rs->rs_lock);
Andy Grover5c115592009-02-24 15:30:27 +0000619
620unlock_and_drop:
Andy Grover561c7df2010-03-11 13:50:06 +0000621 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
Andy Grover5c115592009-02-24 15:30:27 +0000622 rds_message_put(rm);
Andy Grover561c7df2010-03-11 13:50:06 +0000623 if (was_on_sock)
624 rds_message_put(rm);
Andy Grover5c115592009-02-24 15:30:27 +0000625 }
626
627 if (rs) {
Andy Grover5c115592009-02-24 15:30:27 +0000628 rds_wake_sk_sleep(rs);
629 sock_put(rds_rs_to_sk(rs));
630 }
Andy Grover5c115592009-02-24 15:30:27 +0000631}
632
633/*
634 * Transports call here when they've determined that the receiver queued
635 * messages up to, and including, the given sequence number. Messages are
636 * moved to the retrans queue when rds_send_xmit picks them off the send
637 * queue. This means that in the TCP case, the message may not have been
638 * assigned the m_ack_seq yet - but that's fine as long as tcp_is_acked
639 * checks the RDS_MSG_HAS_ACK_SEQ bit.
640 *
641 * XXX It's not clear to me how this is safely serialized with socket
642 * destruction. Maybe it should bail if it sees SOCK_DEAD.
643 */
644void rds_send_drop_acked(struct rds_connection *conn, u64 ack,
645 is_acked_func is_acked)
646{
647 struct rds_message *rm, *tmp;
648 unsigned long flags;
649 LIST_HEAD(list);
650
651 spin_lock_irqsave(&conn->c_lock, flags);
652
653 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
654 if (!rds_send_is_acked(rm, ack, is_acked))
655 break;
656
657 list_move(&rm->m_conn_item, &list);
658 clear_bit(RDS_MSG_ON_CONN, &rm->m_flags);
659 }
660
661 /* order flag updates with spin locks */
662 if (!list_empty(&list))
663 smp_mb__after_clear_bit();
664
665 spin_unlock_irqrestore(&conn->c_lock, flags);
666
667 /* now remove the messages from the sock list as needed */
668 rds_send_remove_from_sock(&list, RDS_RDMA_SUCCESS);
669}
Andy Grover616b7572009-08-21 12:28:32 +0000670EXPORT_SYMBOL_GPL(rds_send_drop_acked);
Andy Grover5c115592009-02-24 15:30:27 +0000671
672void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest)
673{
674 struct rds_message *rm, *tmp;
675 struct rds_connection *conn;
Andy Grover7c82eaf2010-02-19 18:01:41 -0800676 unsigned long flags;
Andy Grover5c115592009-02-24 15:30:27 +0000677 LIST_HEAD(list);
Andy Grover5c115592009-02-24 15:30:27 +0000678
679 /* get all the messages we're dropping under the rs lock */
680 spin_lock_irqsave(&rs->rs_lock, flags);
681
682 list_for_each_entry_safe(rm, tmp, &rs->rs_send_queue, m_sock_item) {
683 if (dest && (dest->sin_addr.s_addr != rm->m_daddr ||
684 dest->sin_port != rm->m_inc.i_hdr.h_dport))
685 continue;
686
Andy Grover5c115592009-02-24 15:30:27 +0000687 list_move(&rm->m_sock_item, &list);
688 rds_send_sndbuf_remove(rs, rm);
689 clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
Andy Grover5c115592009-02-24 15:30:27 +0000690 }
691
692 /* order flag updates with the rs lock */
Andy Grover7c82eaf2010-02-19 18:01:41 -0800693 smp_mb__after_clear_bit();
Andy Grover5c115592009-02-24 15:30:27 +0000694
695 spin_unlock_irqrestore(&rs->rs_lock, flags);
696
Andy Grover7c82eaf2010-02-19 18:01:41 -0800697 if (list_empty(&list))
698 return;
Andy Grover5c115592009-02-24 15:30:27 +0000699
Andy Grover7c82eaf2010-02-19 18:01:41 -0800700 /* Remove the messages from the conn */
Andy Grover5c115592009-02-24 15:30:27 +0000701 list_for_each_entry(rm, &list, m_sock_item) {
Andy Grover7c82eaf2010-02-19 18:01:41 -0800702
703 conn = rm->m_inc.i_conn;
Andy Grover7c82eaf2010-02-19 18:01:41 -0800704
Andy Grover9de08642010-03-29 16:50:54 -0700705 spin_lock_irqsave(&conn->c_lock, flags);
Andy Grover7c82eaf2010-02-19 18:01:41 -0800706 /*
707 * Maybe someone else beat us to removing rm from the conn.
708 * If we race with their flag update we'll get the lock and
709 * then really see that the flag has been cleared.
710 */
711 if (!test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) {
712 spin_unlock_irqrestore(&conn->c_lock, flags);
713 continue;
714 }
Andy Grover9de08642010-03-29 16:50:54 -0700715 list_del_init(&rm->m_conn_item);
716 spin_unlock_irqrestore(&conn->c_lock, flags);
Andy Grover7c82eaf2010-02-19 18:01:41 -0800717
718 /*
719 * Couldn't grab m_rs_lock in top loop (lock ordering),
720 * but we can now.
721 */
Andy Grover9de08642010-03-29 16:50:54 -0700722 spin_lock_irqsave(&rm->m_rs_lock, flags);
Andy Grover7c82eaf2010-02-19 18:01:41 -0800723
Tina Yang550a8002010-03-11 13:50:03 +0000724 spin_lock(&rs->rs_lock);
725 __rds_rdma_send_complete(rs, rm, RDS_RDMA_CANCELED);
726 spin_unlock(&rs->rs_lock);
Andy Grover7c82eaf2010-02-19 18:01:41 -0800727
Andy Grover5c115592009-02-24 15:30:27 +0000728 rm->m_rs = NULL;
Andy Grover9de08642010-03-29 16:50:54 -0700729 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
Andy Grover5c115592009-02-24 15:30:27 +0000730
Andy Grover7c82eaf2010-02-19 18:01:41 -0800731 rds_message_put(rm);
Andy Grover5c115592009-02-24 15:30:27 +0000732 }
733
Andy Grover7c82eaf2010-02-19 18:01:41 -0800734 rds_wake_sk_sleep(rs);
Tina Yang550a8002010-03-11 13:50:03 +0000735
Andy Grover5c115592009-02-24 15:30:27 +0000736 while (!list_empty(&list)) {
737 rm = list_entry(list.next, struct rds_message, m_sock_item);
738 list_del_init(&rm->m_sock_item);
739
740 rds_message_wait(rm);
741 rds_message_put(rm);
742 }
743}
744
745/*
746 * we only want this to fire once so we use the callers 'queued'. It's
747 * possible that another thread can race with us and remove the
748 * message from the flow with RDS_CANCEL_SENT_TO.
749 */
750static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn,
751 struct rds_message *rm, __be16 sport,
752 __be16 dport, int *queued)
753{
754 unsigned long flags;
755 u32 len;
756
757 if (*queued)
758 goto out;
759
760 len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
761
762 /* this is the only place which holds both the socket's rs_lock
763 * and the connection's c_lock */
764 spin_lock_irqsave(&rs->rs_lock, flags);
765
766 /*
767 * If there is a little space in sndbuf, we don't queue anything,
768 * and userspace gets -EAGAIN. But poll() indicates there's send
769 * room. This can lead to bad behavior (spinning) if snd_bytes isn't
770 * freed up by incoming acks. So we check the *old* value of
771 * rs_snd_bytes here to allow the last msg to exceed the buffer,
772 * and poll() now knows no more data can be sent.
773 */
774 if (rs->rs_snd_bytes < rds_sk_sndbuf(rs)) {
775 rs->rs_snd_bytes += len;
776
777 /* let recv side know we are close to send space exhaustion.
778 * This is probably not the optimal way to do it, as this
779 * means we set the flag on *all* messages as soon as our
780 * throughput hits a certain threshold.
781 */
782 if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2)
783 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
784
785 list_add_tail(&rm->m_sock_item, &rs->rs_send_queue);
786 set_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
787 rds_message_addref(rm);
788 rm->m_rs = rs;
789
790 /* The code ordering is a little weird, but we're
791 trying to minimize the time we hold c_lock */
792 rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport, 0);
793 rm->m_inc.i_conn = conn;
794 rds_message_addref(rm);
795
796 spin_lock(&conn->c_lock);
797 rm->m_inc.i_hdr.h_sequence = cpu_to_be64(conn->c_next_tx_seq++);
798 list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
799 set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
800 spin_unlock(&conn->c_lock);
801
802 rdsdebug("queued msg %p len %d, rs %p bytes %d seq %llu\n",
803 rm, len, rs, rs->rs_snd_bytes,
804 (unsigned long long)be64_to_cpu(rm->m_inc.i_hdr.h_sequence));
805
806 *queued = 1;
807 }
808
809 spin_unlock_irqrestore(&rs->rs_lock, flags);
810out:
811 return *queued;
812}
813
Andy Groverfc445082010-01-12 12:56:06 -0800814/*
815 * rds_message is getting to be quite complicated, and we'd like to allocate
816 * it all in one go. This figures out how big it needs to be up front.
817 */
818static int rds_rm_size(struct msghdr *msg, int data_len)
819{
Andy Groverff87e972010-01-12 14:13:15 -0800820 struct cmsghdr *cmsg;
Andy Groverfc445082010-01-12 12:56:06 -0800821 int size = 0;
Andy Groverff87e972010-01-12 14:13:15 -0800822 int retval;
Andy Groverfc445082010-01-12 12:56:06 -0800823
Andy Groverff87e972010-01-12 14:13:15 -0800824 for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
825 if (!CMSG_OK(msg, cmsg))
826 return -EINVAL;
827
828 if (cmsg->cmsg_level != SOL_RDS)
829 continue;
830
831 switch (cmsg->cmsg_type) {
832 case RDS_CMSG_RDMA_ARGS:
833 retval = rds_rdma_extra_size(CMSG_DATA(cmsg));
834 if (retval < 0)
835 return retval;
836 size += retval;
837 break;
838
839 case RDS_CMSG_RDMA_DEST:
840 case RDS_CMSG_RDMA_MAP:
841 /* these are valid but do no add any size */
842 break;
843
Andy Grover15133f62010-01-12 14:33:38 -0800844 case RDS_CMSG_ATOMIC_CSWP:
845 case RDS_CMSG_ATOMIC_FADD:
846 size += sizeof(struct scatterlist);
847 break;
848
Andy Groverff87e972010-01-12 14:13:15 -0800849 default:
850 return -EINVAL;
851 }
852
853 }
854
855 size += ceil(data_len, PAGE_SIZE) * sizeof(struct scatterlist);
Andy Groverfc445082010-01-12 12:56:06 -0800856
857 return size;
858}
859
Andy Grover5c115592009-02-24 15:30:27 +0000860static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
861 struct msghdr *msg, int *allocated_mr)
862{
863 struct cmsghdr *cmsg;
864 int ret = 0;
865
866 for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
867 if (!CMSG_OK(msg, cmsg))
868 return -EINVAL;
869
870 if (cmsg->cmsg_level != SOL_RDS)
871 continue;
872
873 /* As a side effect, RDMA_DEST and RDMA_MAP will set
Andy Grover15133f62010-01-12 14:33:38 -0800874 * rm->rdma.m_rdma_cookie and rm->rdma.m_rdma_mr.
Andy Grover5c115592009-02-24 15:30:27 +0000875 */
876 switch (cmsg->cmsg_type) {
877 case RDS_CMSG_RDMA_ARGS:
878 ret = rds_cmsg_rdma_args(rs, rm, cmsg);
879 break;
880
881 case RDS_CMSG_RDMA_DEST:
882 ret = rds_cmsg_rdma_dest(rs, rm, cmsg);
883 break;
884
885 case RDS_CMSG_RDMA_MAP:
886 ret = rds_cmsg_rdma_map(rs, rm, cmsg);
887 if (!ret)
888 *allocated_mr = 1;
889 break;
Andy Grover15133f62010-01-12 14:33:38 -0800890 case RDS_CMSG_ATOMIC_CSWP:
891 case RDS_CMSG_ATOMIC_FADD:
892 ret = rds_cmsg_atomic(rs, rm, cmsg);
893 break;
Andy Grover5c115592009-02-24 15:30:27 +0000894
895 default:
896 return -EINVAL;
897 }
898
899 if (ret)
900 break;
901 }
902
903 return ret;
904}
905
906int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
907 size_t payload_len)
908{
909 struct sock *sk = sock->sk;
910 struct rds_sock *rs = rds_sk_to_rs(sk);
911 struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name;
912 __be32 daddr;
913 __be16 dport;
914 struct rds_message *rm = NULL;
915 struct rds_connection *conn;
916 int ret = 0;
917 int queued = 0, allocated_mr = 0;
918 int nonblock = msg->msg_flags & MSG_DONTWAIT;
Andy Grover1123fd72010-03-11 13:49:56 +0000919 long timeo = sock_sndtimeo(sk, nonblock);
Andy Grover5c115592009-02-24 15:30:27 +0000920
921 /* Mirror Linux UDP mirror of BSD error message compatibility */
922 /* XXX: Perhaps MSG_MORE someday */
923 if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) {
924 printk(KERN_INFO "msg_flags 0x%08X\n", msg->msg_flags);
925 ret = -EOPNOTSUPP;
926 goto out;
927 }
928
929 if (msg->msg_namelen) {
930 /* XXX fail non-unicast destination IPs? */
931 if (msg->msg_namelen < sizeof(*usin) || usin->sin_family != AF_INET) {
932 ret = -EINVAL;
933 goto out;
934 }
935 daddr = usin->sin_addr.s_addr;
936 dport = usin->sin_port;
937 } else {
938 /* We only care about consistency with ->connect() */
939 lock_sock(sk);
940 daddr = rs->rs_conn_addr;
941 dport = rs->rs_conn_port;
942 release_sock(sk);
943 }
944
945 /* racing with another thread binding seems ok here */
946 if (daddr == 0 || rs->rs_bound_addr == 0) {
947 ret = -ENOTCONN; /* XXX not a great errno */
948 goto out;
949 }
950
Andy Groverfc445082010-01-12 12:56:06 -0800951 /* size of rm including all sgs */
952 ret = rds_rm_size(msg, payload_len);
953 if (ret < 0)
954 goto out;
955
956 rm = rds_message_alloc(ret, GFP_KERNEL);
957 if (!rm) {
958 ret = -ENOMEM;
Andy Grover5c115592009-02-24 15:30:27 +0000959 goto out;
960 }
961
Andy Grover6c7cc6e2010-01-27 18:04:18 -0800962 rm->data.op_sg = rds_message_alloc_sgs(rm, ceil(payload_len, PAGE_SIZE));
Andy Groverfc445082010-01-12 12:56:06 -0800963 /* XXX fix this to not allocate memory */
964 ret = rds_message_copy_from_user(rm, msg->msg_iov, payload_len);
965 if (ret)
966 goto out;
967
Andy Grover5c115592009-02-24 15:30:27 +0000968 rm->m_daddr = daddr;
969
Andy Grover5c115592009-02-24 15:30:27 +0000970 /* rds_conn_create has a spinlock that runs with IRQ off.
971 * Caching the conn in the socket helps a lot. */
972 if (rs->rs_conn && rs->rs_conn->c_faddr == daddr)
973 conn = rs->rs_conn;
974 else {
975 conn = rds_conn_create_outgoing(rs->rs_bound_addr, daddr,
976 rs->rs_transport,
977 sock->sk->sk_allocation);
978 if (IS_ERR(conn)) {
979 ret = PTR_ERR(conn);
980 goto out;
981 }
982 rs->rs_conn = conn;
983 }
984
Andy Grover49f69692009-04-09 14:09:41 +0000985 /* Parse any control messages the user may have included. */
986 ret = rds_cmsg_send(rs, rm, msg, &allocated_mr);
987 if (ret)
988 goto out;
989
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800990 if ((rm->m_rdma_cookie || rm->rdma.op_active) &&
991 !conn->c_trans->xmit_rdma) {
Andy Grover5c115592009-02-24 15:30:27 +0000992 if (printk_ratelimit())
993 printk(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800994 &rm->rdma, conn->c_trans->xmit_rdma);
Andy Grover15133f62010-01-12 14:33:38 -0800995 ret = -EOPNOTSUPP;
996 goto out;
997 }
998
999 if (rm->atomic.op_active && !conn->c_trans->xmit_atomic) {
1000 if (printk_ratelimit())
1001 printk(KERN_NOTICE "atomic_op %p conn xmit_atomic %p\n",
1002 &rm->atomic, conn->c_trans->xmit_atomic);
Andy Grover5c115592009-02-24 15:30:27 +00001003 ret = -EOPNOTSUPP;
1004 goto out;
1005 }
1006
1007 /* If the connection is down, trigger a connect. We may
1008 * have scheduled a delayed reconnect however - in this case
1009 * we should not interfere.
1010 */
Joe Perchesf64f9e72009-11-29 16:55:45 -08001011 if (rds_conn_state(conn) == RDS_CONN_DOWN &&
1012 !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
Andy Grover5c115592009-02-24 15:30:27 +00001013 queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
1014
1015 ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);
Andy Groverb98ba522010-03-11 13:50:04 +00001016 if (ret) {
1017 rs->rs_seen_congestion = 1;
Andy Grover5c115592009-02-24 15:30:27 +00001018 goto out;
Andy Groverb98ba522010-03-11 13:50:04 +00001019 }
Andy Grover5c115592009-02-24 15:30:27 +00001020
1021 while (!rds_send_queue_rm(rs, conn, rm, rs->rs_bound_port,
1022 dport, &queued)) {
1023 rds_stats_inc(s_send_queue_full);
1024 /* XXX make sure this is reasonable */
1025 if (payload_len > rds_sk_sndbuf(rs)) {
1026 ret = -EMSGSIZE;
1027 goto out;
1028 }
1029 if (nonblock) {
1030 ret = -EAGAIN;
1031 goto out;
1032 }
1033
Eric Dumazetaa395142010-04-20 13:03:51 +00001034 timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
Andy Grover5c115592009-02-24 15:30:27 +00001035 rds_send_queue_rm(rs, conn, rm,
1036 rs->rs_bound_port,
1037 dport,
1038 &queued),
1039 timeo);
1040 rdsdebug("sendmsg woke queued %d timeo %ld\n", queued, timeo);
1041 if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
1042 continue;
1043
1044 ret = timeo;
1045 if (ret == 0)
1046 ret = -ETIMEDOUT;
1047 goto out;
1048 }
1049
1050 /*
1051 * By now we've committed to the send. We reuse rds_send_worker()
1052 * to retry sends in the rds thread if the transport asks us to.
1053 */
1054 rds_stats_inc(s_send_queued);
1055
1056 if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
1057 rds_send_worker(&conn->c_send_w.work);
1058
1059 rds_message_put(rm);
1060 return payload_len;
1061
1062out:
1063 /* If the user included a RDMA_MAP cmsg, we allocated a MR on the fly.
1064 * If the sendmsg goes through, we keep the MR. If it fails with EAGAIN
1065 * or in any other way, we need to destroy the MR again */
1066 if (allocated_mr)
1067 rds_rdma_unuse(rs, rds_rdma_cookie_key(rm->m_rdma_cookie), 1);
1068
1069 if (rm)
1070 rds_message_put(rm);
1071 return ret;
1072}
1073
1074/*
1075 * Reply to a ping packet.
1076 */
1077int
1078rds_send_pong(struct rds_connection *conn, __be16 dport)
1079{
1080 struct rds_message *rm;
1081 unsigned long flags;
1082 int ret = 0;
1083
1084 rm = rds_message_alloc(0, GFP_ATOMIC);
Andy Grover8690bfa2010-01-12 11:56:44 -08001085 if (!rm) {
Andy Grover5c115592009-02-24 15:30:27 +00001086 ret = -ENOMEM;
1087 goto out;
1088 }
1089
1090 rm->m_daddr = conn->c_faddr;
1091
1092 /* If the connection is down, trigger a connect. We may
1093 * have scheduled a delayed reconnect however - in this case
1094 * we should not interfere.
1095 */
Joe Perchesf64f9e72009-11-29 16:55:45 -08001096 if (rds_conn_state(conn) == RDS_CONN_DOWN &&
1097 !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
Andy Grover5c115592009-02-24 15:30:27 +00001098 queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
1099
1100 ret = rds_cong_wait(conn->c_fcong, dport, 1, NULL);
1101 if (ret)
1102 goto out;
1103
1104 spin_lock_irqsave(&conn->c_lock, flags);
1105 list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
1106 set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
1107 rds_message_addref(rm);
1108 rm->m_inc.i_conn = conn;
1109
1110 rds_message_populate_header(&rm->m_inc.i_hdr, 0, dport,
1111 conn->c_next_tx_seq);
1112 conn->c_next_tx_seq++;
1113 spin_unlock_irqrestore(&conn->c_lock, flags);
1114
1115 rds_stats_inc(s_send_queued);
1116 rds_stats_inc(s_send_pong);
1117
1118 queue_delayed_work(rds_wq, &conn->c_send_w, 0);
1119 rds_message_put(rm);
1120 return 0;
1121
1122out:
1123 if (rm)
1124 rds_message_put(rm);
1125 return ret;
1126}