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1/*
2 * Copyright (c) 2006 Oracle. All rights reserved.
3 *
4 * This software is available to you under a choice of one of two
5 * licenses. You may choose to be licensed under the terms of the GNU
6 * General Public License (GPL) Version 2, available from the file
7 * COPYING in the main directory of this source tree, or the
8 * OpenIB.org BSD license below:
9 *
10 * Redistribution and use in source and binary forms, with or
11 * without modification, are permitted provided that the following
12 * conditions are met:
13 *
14 * - Redistributions of source code must retain the above
15 * copyright notice, this list of conditions and the following
16 * disclaimer.
17 *
18 * - Redistributions in binary form must reproduce the above
19 * copyright notice, this list of conditions and the following
20 * disclaimer in the documentation and/or other materials
21 * provided with the distribution.
22 *
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30 * SOFTWARE.
31 *
32 */
33#include <linux/kernel.h>
34#include <linux/moduleparam.h>
35#include <linux/gfp.h>
36#include <net/sock.h>
37#include <linux/in.h>
38#include <linux/list.h>
39#include <linux/ratelimit.h>
40#include <linux/export.h>
41#include <linux/sizes.h>
42
43#include "rds.h"
44
45/* When transmitting messages in rds_send_xmit, we need to emerge from
46 * time to time and briefly release the CPU. Otherwise the softlock watchdog
47 * will kick our shin.
48 * Also, it seems fairer to not let one busy connection stall all the
49 * others.
50 *
51 * send_batch_count is the number of times we'll loop in send_xmit. Setting
52 * it to 0 will restore the old behavior (where we looped until we had
53 * drained the queue).
54 */
55static int send_batch_count = SZ_1K;
56module_param(send_batch_count, int, 0444);
57MODULE_PARM_DESC(send_batch_count, " batch factor when working the send queue");
58
59static void rds_send_remove_from_sock(struct list_head *messages, int status);
60
61/*
62 * Reset the send state. Callers must ensure that this doesn't race with
63 * rds_send_xmit().
64 */
65void rds_send_reset(struct rds_connection *conn)
66{
67 struct rds_message *rm, *tmp;
68 unsigned long flags;
69
70 if (conn->c_xmit_rm) {
71 rm = conn->c_xmit_rm;
72 conn->c_xmit_rm = NULL;
73 /* Tell the user the RDMA op is no longer mapped by the
74 * transport. This isn't entirely true (it's flushed out
75 * independently) but as the connection is down, there's
76 * no ongoing RDMA to/from that memory */
77 rds_message_unmapped(rm);
78 rds_message_put(rm);
79 }
80
81 conn->c_xmit_sg = 0;
82 conn->c_xmit_hdr_off = 0;
83 conn->c_xmit_data_off = 0;
84 conn->c_xmit_atomic_sent = 0;
85 conn->c_xmit_rdma_sent = 0;
86 conn->c_xmit_data_sent = 0;
87
88 conn->c_map_queued = 0;
89
90 conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
91 conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
92
93 /* Mark messages as retransmissions, and move them to the send q */
94 spin_lock_irqsave(&conn->c_lock, flags);
95 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
96 set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
97 set_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags);
98 }
99 list_splice_init(&conn->c_retrans, &conn->c_send_queue);
100 spin_unlock_irqrestore(&conn->c_lock, flags);
101}
102
103static int acquire_in_xmit(struct rds_connection *conn)
104{
105 return test_and_set_bit(RDS_IN_XMIT, &conn->c_flags) == 0;
106}
107
108static void release_in_xmit(struct rds_connection *conn)
109{
110 clear_bit(RDS_IN_XMIT, &conn->c_flags);
111 smp_mb__after_atomic();
112 /*
113 * We don't use wait_on_bit()/wake_up_bit() because our waking is in a
114 * hot path and finding waiters is very rare. We don't want to walk
115 * the system-wide hashed waitqueue buckets in the fast path only to
116 * almost never find waiters.
117 */
118 if (waitqueue_active(&conn->c_waitq))
119 wake_up_all(&conn->c_waitq);
120}
121
122/*
123 * We're making the conscious trade-off here to only send one message
124 * down the connection at a time.
125 * Pro:
126 * - tx queueing is a simple fifo list
127 * - reassembly is optional and easily done by transports per conn
128 * - no per flow rx lookup at all, straight to the socket
129 * - less per-frag memory and wire overhead
130 * Con:
131 * - queued acks can be delayed behind large messages
132 * Depends:
133 * - small message latency is higher behind queued large messages
134 * - large message latency isn't starved by intervening small sends
135 */
136int rds_send_xmit(struct rds_connection *conn)
137{
138 struct rds_message *rm;
139 unsigned long flags;
140 unsigned int tmp;
141 struct scatterlist *sg;
142 int ret = 0;
143 LIST_HEAD(to_be_dropped);
144 int batch_count;
145 unsigned long send_gen = 0;
146
147restart:
148 batch_count = 0;
149
150 /*
151 * sendmsg calls here after having queued its message on the send
152 * queue. We only have one task feeding the connection at a time. If
153 * another thread is already feeding the queue then we back off. This
154 * avoids blocking the caller and trading per-connection data between
155 * caches per message.
156 */
157 if (!acquire_in_xmit(conn)) {
158 rds_stats_inc(s_send_lock_contention);
159 ret = -ENOMEM;
160 goto out;
161 }
162
163 /*
164 * we record the send generation after doing the xmit acquire.
165 * if someone else manages to jump in and do some work, we'll use
166 * this to avoid a goto restart farther down.
167 *
168 * The acquire_in_xmit() check above ensures that only one
169 * caller can increment c_send_gen at any time.
170 */
171 conn->c_send_gen++;
172 send_gen = conn->c_send_gen;
173
174 /*
175 * rds_conn_shutdown() sets the conn state and then tests RDS_IN_XMIT,
176 * we do the opposite to avoid races.
177 */
178 if (!rds_conn_up(conn)) {
179 release_in_xmit(conn);
180 ret = 0;
181 goto out;
182 }
183
184 if (conn->c_trans->xmit_prepare)
185 conn->c_trans->xmit_prepare(conn);
186
187 /*
188 * spin trying to push headers and data down the connection until
189 * the connection doesn't make forward progress.
190 */
191 while (1) {
192
193 rm = conn->c_xmit_rm;
194
195 /*
196 * If between sending messages, we can send a pending congestion
197 * map update.
198 */
199 if (!rm && test_and_clear_bit(0, &conn->c_map_queued)) {
200 rm = rds_cong_update_alloc(conn);
201 if (IS_ERR(rm)) {
202 ret = PTR_ERR(rm);
203 break;
204 }
205 rm->data.op_active = 1;
206
207 conn->c_xmit_rm = rm;
208 }
209
210 /*
211 * If not already working on one, grab the next message.
212 *
213 * c_xmit_rm holds a ref while we're sending this message down
214 * the connction. We can use this ref while holding the
215 * send_sem.. rds_send_reset() is serialized with it.
216 */
217 if (!rm) {
218 unsigned int len;
219
220 batch_count++;
221
222 /* we want to process as big a batch as we can, but
223 * we also want to avoid softlockups. If we've been
224 * through a lot of messages, lets back off and see
225 * if anyone else jumps in
226 */
227 if (batch_count >= send_batch_count)
228 goto over_batch;
229
230 spin_lock_irqsave(&conn->c_lock, flags);
231
232 if (!list_empty(&conn->c_send_queue)) {
233 rm = list_entry(conn->c_send_queue.next,
234 struct rds_message,
235 m_conn_item);
236 rds_message_addref(rm);
237
238 /*
239 * Move the message from the send queue to the retransmit
240 * list right away.
241 */
242 list_move_tail(&rm->m_conn_item, &conn->c_retrans);
243 }
244
245 spin_unlock_irqrestore(&conn->c_lock, flags);
246
247 if (!rm)
248 break;
249
250 /* Unfortunately, the way Infiniband deals with
251 * RDMA to a bad MR key is by moving the entire
252 * queue pair to error state. We cold possibly
253 * recover from that, but right now we drop the
254 * connection.
255 * Therefore, we never retransmit messages with RDMA ops.
256 */
257 if (rm->rdma.op_active &&
258 test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) {
259 spin_lock_irqsave(&conn->c_lock, flags);
260 if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags))
261 list_move(&rm->m_conn_item, &to_be_dropped);
262 spin_unlock_irqrestore(&conn->c_lock, flags);
263 continue;
264 }
265
266 /* Require an ACK every once in a while */
267 len = ntohl(rm->m_inc.i_hdr.h_len);
268 if (conn->c_unacked_packets == 0 ||
269 conn->c_unacked_bytes < len) {
270 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
271
272 conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
273 conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
274 rds_stats_inc(s_send_ack_required);
275 } else {
276 conn->c_unacked_bytes -= len;
277 conn->c_unacked_packets--;
278 }
279
280 conn->c_xmit_rm = rm;
281 }
282
283 /* The transport either sends the whole rdma or none of it */
284 if (rm->rdma.op_active && !conn->c_xmit_rdma_sent) {
285 rm->m_final_op = &rm->rdma;
286 /* The transport owns the mapped memory for now.
287 * You can't unmap it while it's on the send queue
288 */
289 set_bit(RDS_MSG_MAPPED, &rm->m_flags);
290 ret = conn->c_trans->xmit_rdma(conn, &rm->rdma);
291 if (ret) {
292 clear_bit(RDS_MSG_MAPPED, &rm->m_flags);
293 wake_up_interruptible(&rm->m_flush_wait);
294 break;
295 }
296 conn->c_xmit_rdma_sent = 1;
297
298 }
299
300 if (rm->atomic.op_active && !conn->c_xmit_atomic_sent) {
301 rm->m_final_op = &rm->atomic;
302 /* The transport owns the mapped memory for now.
303 * You can't unmap it while it's on the send queue
304 */
305 set_bit(RDS_MSG_MAPPED, &rm->m_flags);
306 ret = conn->c_trans->xmit_atomic(conn, &rm->atomic);
307 if (ret) {
308 clear_bit(RDS_MSG_MAPPED, &rm->m_flags);
309 wake_up_interruptible(&rm->m_flush_wait);
310 break;
311 }
312 conn->c_xmit_atomic_sent = 1;
313
314 }
315
316 /*
317 * A number of cases require an RDS header to be sent
318 * even if there is no data.
319 * We permit 0-byte sends; rds-ping depends on this.
320 * However, if there are exclusively attached silent ops,
321 * we skip the hdr/data send, to enable silent operation.
322 */
323 if (rm->data.op_nents == 0) {
324 int ops_present;
325 int all_ops_are_silent = 1;
326
327 ops_present = (rm->atomic.op_active || rm->rdma.op_active);
328 if (rm->atomic.op_active && !rm->atomic.op_silent)
329 all_ops_are_silent = 0;
330 if (rm->rdma.op_active && !rm->rdma.op_silent)
331 all_ops_are_silent = 0;
332
333 if (ops_present && all_ops_are_silent
334 && !rm->m_rdma_cookie)
335 rm->data.op_active = 0;
336 }
337
338 if (rm->data.op_active && !conn->c_xmit_data_sent) {
339 rm->m_final_op = &rm->data;
340 ret = conn->c_trans->xmit(conn, rm,
341 conn->c_xmit_hdr_off,
342 conn->c_xmit_sg,
343 conn->c_xmit_data_off);
344 if (ret <= 0)
345 break;
346
347 if (conn->c_xmit_hdr_off < sizeof(struct rds_header)) {
348 tmp = min_t(int, ret,
349 sizeof(struct rds_header) -
350 conn->c_xmit_hdr_off);
351 conn->c_xmit_hdr_off += tmp;
352 ret -= tmp;
353 }
354
355 sg = &rm->data.op_sg[conn->c_xmit_sg];
356 while (ret) {
357 tmp = min_t(int, ret, sg->length -
358 conn->c_xmit_data_off);
359 conn->c_xmit_data_off += tmp;
360 ret -= tmp;
361 if (conn->c_xmit_data_off == sg->length) {
362 conn->c_xmit_data_off = 0;
363 sg++;
364 conn->c_xmit_sg++;
365 BUG_ON(ret != 0 &&
366 conn->c_xmit_sg == rm->data.op_nents);
367 }
368 }
369
370 if (conn->c_xmit_hdr_off == sizeof(struct rds_header) &&
371 (conn->c_xmit_sg == rm->data.op_nents))
372 conn->c_xmit_data_sent = 1;
373 }
374
375 /*
376 * A rm will only take multiple times through this loop
377 * if there is a data op. Thus, if the data is sent (or there was
378 * none), then we're done with the rm.
379 */
380 if (!rm->data.op_active || conn->c_xmit_data_sent) {
381 conn->c_xmit_rm = NULL;
382 conn->c_xmit_sg = 0;
383 conn->c_xmit_hdr_off = 0;
384 conn->c_xmit_data_off = 0;
385 conn->c_xmit_rdma_sent = 0;
386 conn->c_xmit_atomic_sent = 0;
387 conn->c_xmit_data_sent = 0;
388
389 rds_message_put(rm);
390 }
391 }
392
393over_batch:
394 if (conn->c_trans->xmit_complete)
395 conn->c_trans->xmit_complete(conn);
396 release_in_xmit(conn);
397
398 /* Nuke any messages we decided not to retransmit. */
399 if (!list_empty(&to_be_dropped)) {
400 /* irqs on here, so we can put(), unlike above */
401 list_for_each_entry(rm, &to_be_dropped, m_conn_item)
402 rds_message_put(rm);
403 rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED);
404 }
405
406 /*
407 * Other senders can queue a message after we last test the send queue
408 * but before we clear RDS_IN_XMIT. In that case they'd back off and
409 * not try and send their newly queued message. We need to check the
410 * send queue after having cleared RDS_IN_XMIT so that their message
411 * doesn't get stuck on the send queue.
412 *
413 * If the transport cannot continue (i.e ret != 0), then it must
414 * call us when more room is available, such as from the tx
415 * completion handler.
416 *
417 * We have an extra generation check here so that if someone manages
418 * to jump in after our release_in_xmit, we'll see that they have done
419 * some work and we will skip our goto
420 */
421 if (ret == 0) {
422 smp_mb();
423 if ((test_bit(0, &conn->c_map_queued) ||
424 !list_empty(&conn->c_send_queue)) &&
425 send_gen == conn->c_send_gen) {
426 rds_stats_inc(s_send_lock_queue_raced);
427 if (batch_count < send_batch_count)
428 goto restart;
429 queue_delayed_work(rds_wq, &conn->c_send_w, 1);
430 }
431 }
432out:
433 return ret;
434}
435EXPORT_SYMBOL_GPL(rds_send_xmit);
436
437static void rds_send_sndbuf_remove(struct rds_sock *rs, struct rds_message *rm)
438{
439 u32 len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
440
441 assert_spin_locked(&rs->rs_lock);
442
443 BUG_ON(rs->rs_snd_bytes < len);
444 rs->rs_snd_bytes -= len;
445
446 if (rs->rs_snd_bytes == 0)
447 rds_stats_inc(s_send_queue_empty);
448}
449
450static inline int rds_send_is_acked(struct rds_message *rm, u64 ack,
451 is_acked_func is_acked)
452{
453 if (is_acked)
454 return is_acked(rm, ack);
455 return be64_to_cpu(rm->m_inc.i_hdr.h_sequence) <= ack;
456}
457
458/*
459 * This is pretty similar to what happens below in the ACK
460 * handling code - except that we call here as soon as we get
461 * the IB send completion on the RDMA op and the accompanying
462 * message.
463 */
464void rds_rdma_send_complete(struct rds_message *rm, int status)
465{
466 struct rds_sock *rs = NULL;
467 struct rm_rdma_op *ro;
468 struct rds_notifier *notifier;
469 unsigned long flags;
470
471 spin_lock_irqsave(&rm->m_rs_lock, flags);
472
473 ro = &rm->rdma;
474 if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) &&
475 ro->op_active && ro->op_notify && ro->op_notifier) {
476 notifier = ro->op_notifier;
477 rs = rm->m_rs;
478 sock_hold(rds_rs_to_sk(rs));
479
480 notifier->n_status = status;
481 spin_lock(&rs->rs_lock);
482 list_add_tail(¬ifier->n_list, &rs->rs_notify_queue);
483 spin_unlock(&rs->rs_lock);
484
485 ro->op_notifier = NULL;
486 }
487
488 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
489
490 if (rs) {
491 rds_wake_sk_sleep(rs);
492 sock_put(rds_rs_to_sk(rs));
493 }
494}
495EXPORT_SYMBOL_GPL(rds_rdma_send_complete);
496
497/*
498 * Just like above, except looks at atomic op
499 */
500void rds_atomic_send_complete(struct rds_message *rm, int status)
501{
502 struct rds_sock *rs = NULL;
503 struct rm_atomic_op *ao;
504 struct rds_notifier *notifier;
505 unsigned long flags;
506
507 spin_lock_irqsave(&rm->m_rs_lock, flags);
508
509 ao = &rm->atomic;
510 if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags)
511 && ao->op_active && ao->op_notify && ao->op_notifier) {
512 notifier = ao->op_notifier;
513 rs = rm->m_rs;
514 sock_hold(rds_rs_to_sk(rs));
515
516 notifier->n_status = status;
517 spin_lock(&rs->rs_lock);
518 list_add_tail(¬ifier->n_list, &rs->rs_notify_queue);
519 spin_unlock(&rs->rs_lock);
520
521 ao->op_notifier = NULL;
522 }
523
524 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
525
526 if (rs) {
527 rds_wake_sk_sleep(rs);
528 sock_put(rds_rs_to_sk(rs));
529 }
530}
531EXPORT_SYMBOL_GPL(rds_atomic_send_complete);
532
533/*
534 * This is the same as rds_rdma_send_complete except we
535 * don't do any locking - we have all the ingredients (message,
536 * socket, socket lock) and can just move the notifier.
537 */
538static inline void
539__rds_send_complete(struct rds_sock *rs, struct rds_message *rm, int status)
540{
541 struct rm_rdma_op *ro;
542 struct rm_atomic_op *ao;
543
544 ro = &rm->rdma;
545 if (ro->op_active && ro->op_notify && ro->op_notifier) {
546 ro->op_notifier->n_status = status;
547 list_add_tail(&ro->op_notifier->n_list, &rs->rs_notify_queue);
548 ro->op_notifier = NULL;
549 }
550
551 ao = &rm->atomic;
552 if (ao->op_active && ao->op_notify && ao->op_notifier) {
553 ao->op_notifier->n_status = status;
554 list_add_tail(&ao->op_notifier->n_list, &rs->rs_notify_queue);
555 ao->op_notifier = NULL;
556 }
557
558 /* No need to wake the app - caller does this */
559}
560
561/*
562 * This is called from the IB send completion when we detect
563 * a RDMA operation that failed with remote access error.
564 * So speed is not an issue here.
565 */
566struct rds_message *rds_send_get_message(struct rds_connection *conn,
567 struct rm_rdma_op *op)
568{
569 struct rds_message *rm, *tmp, *found = NULL;
570 unsigned long flags;
571
572 spin_lock_irqsave(&conn->c_lock, flags);
573
574 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
575 if (&rm->rdma == op) {
576 atomic_inc(&rm->m_refcount);
577 found = rm;
578 goto out;
579 }
580 }
581
582 list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
583 if (&rm->rdma == op) {
584 atomic_inc(&rm->m_refcount);
585 found = rm;
586 break;
587 }
588 }
589
590out:
591 spin_unlock_irqrestore(&conn->c_lock, flags);
592
593 return found;
594}
595EXPORT_SYMBOL_GPL(rds_send_get_message);
596
597/*
598 * This removes messages from the socket's list if they're on it. The list
599 * argument must be private to the caller, we must be able to modify it
600 * without locks. The messages must have a reference held for their
601 * position on the list. This function will drop that reference after
602 * removing the messages from the 'messages' list regardless of if it found
603 * the messages on the socket list or not.
604 */
605static void rds_send_remove_from_sock(struct list_head *messages, int status)
606{
607 unsigned long flags;
608 struct rds_sock *rs = NULL;
609 struct rds_message *rm;
610
611 while (!list_empty(messages)) {
612 int was_on_sock = 0;
613
614 rm = list_entry(messages->next, struct rds_message,
615 m_conn_item);
616 list_del_init(&rm->m_conn_item);
617
618 /*
619 * If we see this flag cleared then we're *sure* that someone
620 * else beat us to removing it from the sock. If we race
621 * with their flag update we'll get the lock and then really
622 * see that the flag has been cleared.
623 *
624 * The message spinlock makes sure nobody clears rm->m_rs
625 * while we're messing with it. It does not prevent the
626 * message from being removed from the socket, though.
627 */
628 spin_lock_irqsave(&rm->m_rs_lock, flags);
629 if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags))
630 goto unlock_and_drop;
631
632 if (rs != rm->m_rs) {
633 if (rs) {
634 rds_wake_sk_sleep(rs);
635 sock_put(rds_rs_to_sk(rs));
636 }
637 rs = rm->m_rs;
638 if (rs)
639 sock_hold(rds_rs_to_sk(rs));
640 }
641 if (!rs)
642 goto unlock_and_drop;
643 spin_lock(&rs->rs_lock);
644
645 if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) {
646 struct rm_rdma_op *ro = &rm->rdma;
647 struct rds_notifier *notifier;
648
649 list_del_init(&rm->m_sock_item);
650 rds_send_sndbuf_remove(rs, rm);
651
652 if (ro->op_active && ro->op_notifier &&
653 (ro->op_notify || (ro->op_recverr && status))) {
654 notifier = ro->op_notifier;
655 list_add_tail(¬ifier->n_list,
656 &rs->rs_notify_queue);
657 if (!notifier->n_status)
658 notifier->n_status = status;
659 rm->rdma.op_notifier = NULL;
660 }
661 was_on_sock = 1;
662 rm->m_rs = NULL;
663 }
664 spin_unlock(&rs->rs_lock);
665
666unlock_and_drop:
667 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
668 rds_message_put(rm);
669 if (was_on_sock)
670 rds_message_put(rm);
671 }
672
673 if (rs) {
674 rds_wake_sk_sleep(rs);
675 sock_put(rds_rs_to_sk(rs));
676 }
677}
678
679/*
680 * Transports call here when they've determined that the receiver queued
681 * messages up to, and including, the given sequence number. Messages are
682 * moved to the retrans queue when rds_send_xmit picks them off the send
683 * queue. This means that in the TCP case, the message may not have been
684 * assigned the m_ack_seq yet - but that's fine as long as tcp_is_acked
685 * checks the RDS_MSG_HAS_ACK_SEQ bit.
686 */
687void rds_send_drop_acked(struct rds_connection *conn, u64 ack,
688 is_acked_func is_acked)
689{
690 struct rds_message *rm, *tmp;
691 unsigned long flags;
692 LIST_HEAD(list);
693
694 spin_lock_irqsave(&conn->c_lock, flags);
695
696 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
697 if (!rds_send_is_acked(rm, ack, is_acked))
698 break;
699
700 list_move(&rm->m_conn_item, &list);
701 clear_bit(RDS_MSG_ON_CONN, &rm->m_flags);
702 }
703
704 /* order flag updates with spin locks */
705 if (!list_empty(&list))
706 smp_mb__after_atomic();
707
708 spin_unlock_irqrestore(&conn->c_lock, flags);
709
710 /* now remove the messages from the sock list as needed */
711 rds_send_remove_from_sock(&list, RDS_RDMA_SUCCESS);
712}
713EXPORT_SYMBOL_GPL(rds_send_drop_acked);
714
715void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest)
716{
717 struct rds_message *rm, *tmp;
718 struct rds_connection *conn;
719 unsigned long flags;
720 LIST_HEAD(list);
721
722 /* get all the messages we're dropping under the rs lock */
723 spin_lock_irqsave(&rs->rs_lock, flags);
724
725 list_for_each_entry_safe(rm, tmp, &rs->rs_send_queue, m_sock_item) {
726 if (dest && (dest->sin_addr.s_addr != rm->m_daddr ||
727 dest->sin_port != rm->m_inc.i_hdr.h_dport))
728 continue;
729
730 list_move(&rm->m_sock_item, &list);
731 rds_send_sndbuf_remove(rs, rm);
732 clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
733 }
734
735 /* order flag updates with the rs lock */
736 smp_mb__after_atomic();
737
738 spin_unlock_irqrestore(&rs->rs_lock, flags);
739
740 if (list_empty(&list))
741 return;
742
743 /* Remove the messages from the conn */
744 list_for_each_entry(rm, &list, m_sock_item) {
745
746 conn = rm->m_inc.i_conn;
747
748 spin_lock_irqsave(&conn->c_lock, flags);
749 /*
750 * Maybe someone else beat us to removing rm from the conn.
751 * If we race with their flag update we'll get the lock and
752 * then really see that the flag has been cleared.
753 */
754 if (!test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) {
755 spin_unlock_irqrestore(&conn->c_lock, flags);
756 spin_lock_irqsave(&rm->m_rs_lock, flags);
757 rm->m_rs = NULL;
758 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
759 continue;
760 }
761 list_del_init(&rm->m_conn_item);
762 spin_unlock_irqrestore(&conn->c_lock, flags);
763
764 /*
765 * Couldn't grab m_rs_lock in top loop (lock ordering),
766 * but we can now.
767 */
768 spin_lock_irqsave(&rm->m_rs_lock, flags);
769
770 spin_lock(&rs->rs_lock);
771 __rds_send_complete(rs, rm, RDS_RDMA_CANCELED);
772 spin_unlock(&rs->rs_lock);
773
774 rm->m_rs = NULL;
775 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
776
777 rds_message_put(rm);
778 }
779
780 rds_wake_sk_sleep(rs);
781
782 while (!list_empty(&list)) {
783 rm = list_entry(list.next, struct rds_message, m_sock_item);
784 list_del_init(&rm->m_sock_item);
785 rds_message_wait(rm);
786
787 /* just in case the code above skipped this message
788 * because RDS_MSG_ON_CONN wasn't set, run it again here
789 * taking m_rs_lock is the only thing that keeps us
790 * from racing with ack processing.
791 */
792 spin_lock_irqsave(&rm->m_rs_lock, flags);
793
794 spin_lock(&rs->rs_lock);
795 __rds_send_complete(rs, rm, RDS_RDMA_CANCELED);
796 spin_unlock(&rs->rs_lock);
797
798 rm->m_rs = NULL;
799 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
800
801 rds_message_put(rm);
802 }
803}
804
805/*
806 * we only want this to fire once so we use the callers 'queued'. It's
807 * possible that another thread can race with us and remove the
808 * message from the flow with RDS_CANCEL_SENT_TO.
809 */
810static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn,
811 struct rds_message *rm, __be16 sport,
812 __be16 dport, int *queued)
813{
814 unsigned long flags;
815 u32 len;
816
817 if (*queued)
818 goto out;
819
820 len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
821
822 /* this is the only place which holds both the socket's rs_lock
823 * and the connection's c_lock */
824 spin_lock_irqsave(&rs->rs_lock, flags);
825
826 /*
827 * If there is a little space in sndbuf, we don't queue anything,
828 * and userspace gets -EAGAIN. But poll() indicates there's send
829 * room. This can lead to bad behavior (spinning) if snd_bytes isn't
830 * freed up by incoming acks. So we check the *old* value of
831 * rs_snd_bytes here to allow the last msg to exceed the buffer,
832 * and poll() now knows no more data can be sent.
833 */
834 if (rs->rs_snd_bytes < rds_sk_sndbuf(rs)) {
835 rs->rs_snd_bytes += len;
836
837 /* let recv side know we are close to send space exhaustion.
838 * This is probably not the optimal way to do it, as this
839 * means we set the flag on *all* messages as soon as our
840 * throughput hits a certain threshold.
841 */
842 if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2)
843 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
844
845 list_add_tail(&rm->m_sock_item, &rs->rs_send_queue);
846 set_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
847 rds_message_addref(rm);
848 rm->m_rs = rs;
849
850 /* The code ordering is a little weird, but we're
851 trying to minimize the time we hold c_lock */
852 rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport, 0);
853 rm->m_inc.i_conn = conn;
854 rds_message_addref(rm);
855
856 spin_lock(&conn->c_lock);
857 rm->m_inc.i_hdr.h_sequence = cpu_to_be64(conn->c_next_tx_seq++);
858 list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
859 set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
860 spin_unlock(&conn->c_lock);
861
862 rdsdebug("queued msg %p len %d, rs %p bytes %d seq %llu\n",
863 rm, len, rs, rs->rs_snd_bytes,
864 (unsigned long long)be64_to_cpu(rm->m_inc.i_hdr.h_sequence));
865
866 *queued = 1;
867 }
868
869 spin_unlock_irqrestore(&rs->rs_lock, flags);
870out:
871 return *queued;
872}
873
874/*
875 * rds_message is getting to be quite complicated, and we'd like to allocate
876 * it all in one go. This figures out how big it needs to be up front.
877 */
878static int rds_rm_size(struct msghdr *msg, int data_len)
879{
880 struct cmsghdr *cmsg;
881 int size = 0;
882 int cmsg_groups = 0;
883 int retval;
884
885 for_each_cmsghdr(cmsg, msg) {
886 if (!CMSG_OK(msg, cmsg))
887 return -EINVAL;
888
889 if (cmsg->cmsg_level != SOL_RDS)
890 continue;
891
892 switch (cmsg->cmsg_type) {
893 case RDS_CMSG_RDMA_ARGS:
894 cmsg_groups |= 1;
895 retval = rds_rdma_extra_size(CMSG_DATA(cmsg));
896 if (retval < 0)
897 return retval;
898 size += retval;
899
900 break;
901
902 case RDS_CMSG_RDMA_DEST:
903 case RDS_CMSG_RDMA_MAP:
904 cmsg_groups |= 2;
905 /* these are valid but do no add any size */
906 break;
907
908 case RDS_CMSG_ATOMIC_CSWP:
909 case RDS_CMSG_ATOMIC_FADD:
910 case RDS_CMSG_MASKED_ATOMIC_CSWP:
911 case RDS_CMSG_MASKED_ATOMIC_FADD:
912 cmsg_groups |= 1;
913 size += sizeof(struct scatterlist);
914 break;
915
916 default:
917 return -EINVAL;
918 }
919
920 }
921
922 size += ceil(data_len, PAGE_SIZE) * sizeof(struct scatterlist);
923
924 /* Ensure (DEST, MAP) are never used with (ARGS, ATOMIC) */
925 if (cmsg_groups == 3)
926 return -EINVAL;
927
928 return size;
929}
930
931static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
932 struct msghdr *msg, int *allocated_mr)
933{
934 struct cmsghdr *cmsg;
935 int ret = 0;
936
937 for_each_cmsghdr(cmsg, msg) {
938 if (!CMSG_OK(msg, cmsg))
939 return -EINVAL;
940
941 if (cmsg->cmsg_level != SOL_RDS)
942 continue;
943
944 /* As a side effect, RDMA_DEST and RDMA_MAP will set
945 * rm->rdma.m_rdma_cookie and rm->rdma.m_rdma_mr.
946 */
947 switch (cmsg->cmsg_type) {
948 case RDS_CMSG_RDMA_ARGS:
949 ret = rds_cmsg_rdma_args(rs, rm, cmsg);
950 break;
951
952 case RDS_CMSG_RDMA_DEST:
953 ret = rds_cmsg_rdma_dest(rs, rm, cmsg);
954 break;
955
956 case RDS_CMSG_RDMA_MAP:
957 ret = rds_cmsg_rdma_map(rs, rm, cmsg);
958 if (!ret)
959 *allocated_mr = 1;
960 break;
961 case RDS_CMSG_ATOMIC_CSWP:
962 case RDS_CMSG_ATOMIC_FADD:
963 case RDS_CMSG_MASKED_ATOMIC_CSWP:
964 case RDS_CMSG_MASKED_ATOMIC_FADD:
965 ret = rds_cmsg_atomic(rs, rm, cmsg);
966 break;
967
968 default:
969 return -EINVAL;
970 }
971
972 if (ret)
973 break;
974 }
975
976 return ret;
977}
978
979int rds_sendmsg(struct socket *sock, struct msghdr *msg, size_t payload_len)
980{
981 struct sock *sk = sock->sk;
982 struct rds_sock *rs = rds_sk_to_rs(sk);
983 DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
984 __be32 daddr;
985 __be16 dport;
986 struct rds_message *rm = NULL;
987 struct rds_connection *conn;
988 int ret = 0;
989 int queued = 0, allocated_mr = 0;
990 int nonblock = msg->msg_flags & MSG_DONTWAIT;
991 long timeo = sock_sndtimeo(sk, nonblock);
992
993 /* Mirror Linux UDP mirror of BSD error message compatibility */
994 /* XXX: Perhaps MSG_MORE someday */
995 if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) {
996 ret = -EOPNOTSUPP;
997 goto out;
998 }
999
1000 if (msg->msg_namelen) {
1001 /* XXX fail non-unicast destination IPs? */
1002 if (msg->msg_namelen < sizeof(*usin) || usin->sin_family != AF_INET) {
1003 ret = -EINVAL;
1004 goto out;
1005 }
1006 daddr = usin->sin_addr.s_addr;
1007 dport = usin->sin_port;
1008 } else {
1009 /* We only care about consistency with ->connect() */
1010 lock_sock(sk);
1011 daddr = rs->rs_conn_addr;
1012 dport = rs->rs_conn_port;
1013 release_sock(sk);
1014 }
1015
1016 lock_sock(sk);
1017 if (daddr == 0 || rs->rs_bound_addr == 0) {
1018 release_sock(sk);
1019 ret = -ENOTCONN; /* XXX not a great errno */
1020 goto out;
1021 }
1022 release_sock(sk);
1023
1024 if (payload_len > rds_sk_sndbuf(rs)) {
1025 ret = -EMSGSIZE;
1026 goto out;
1027 }
1028
1029 /* size of rm including all sgs */
1030 ret = rds_rm_size(msg, payload_len);
1031 if (ret < 0)
1032 goto out;
1033
1034 rm = rds_message_alloc(ret, GFP_KERNEL);
1035 if (!rm) {
1036 ret = -ENOMEM;
1037 goto out;
1038 }
1039
1040 /* Attach data to the rm */
1041 if (payload_len) {
1042 rm->data.op_sg = rds_message_alloc_sgs(rm, ceil(payload_len, PAGE_SIZE));
1043 if (!rm->data.op_sg) {
1044 ret = -ENOMEM;
1045 goto out;
1046 }
1047 ret = rds_message_copy_from_user(rm, &msg->msg_iter);
1048 if (ret)
1049 goto out;
1050 }
1051 rm->data.op_active = 1;
1052
1053 rm->m_daddr = daddr;
1054
1055 /* rds_conn_create has a spinlock that runs with IRQ off.
1056 * Caching the conn in the socket helps a lot. */
1057 if (rs->rs_conn && rs->rs_conn->c_faddr == daddr)
1058 conn = rs->rs_conn;
1059 else {
1060 conn = rds_conn_create_outgoing(sock_net(sock->sk),
1061 rs->rs_bound_addr, daddr,
1062 rs->rs_transport,
1063 sock->sk->sk_allocation);
1064 if (IS_ERR(conn)) {
1065 ret = PTR_ERR(conn);
1066 goto out;
1067 }
1068 rs->rs_conn = conn;
1069 }
1070
1071 /* Parse any control messages the user may have included. */
1072 ret = rds_cmsg_send(rs, rm, msg, &allocated_mr);
1073 if (ret)
1074 goto out;
1075
1076 if (rm->rdma.op_active && !conn->c_trans->xmit_rdma) {
1077 printk_ratelimited(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",
1078 &rm->rdma, conn->c_trans->xmit_rdma);
1079 ret = -EOPNOTSUPP;
1080 goto out;
1081 }
1082
1083 if (rm->atomic.op_active && !conn->c_trans->xmit_atomic) {
1084 printk_ratelimited(KERN_NOTICE "atomic_op %p conn xmit_atomic %p\n",
1085 &rm->atomic, conn->c_trans->xmit_atomic);
1086 ret = -EOPNOTSUPP;
1087 goto out;
1088 }
1089
1090 rds_conn_connect_if_down(conn);
1091
1092 ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);
1093 if (ret) {
1094 rs->rs_seen_congestion = 1;
1095 goto out;
1096 }
1097
1098 while (!rds_send_queue_rm(rs, conn, rm, rs->rs_bound_port,
1099 dport, &queued)) {
1100 rds_stats_inc(s_send_queue_full);
1101
1102 if (nonblock) {
1103 ret = -EAGAIN;
1104 goto out;
1105 }
1106
1107 timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
1108 rds_send_queue_rm(rs, conn, rm,
1109 rs->rs_bound_port,
1110 dport,
1111 &queued),
1112 timeo);
1113 rdsdebug("sendmsg woke queued %d timeo %ld\n", queued, timeo);
1114 if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
1115 continue;
1116
1117 ret = timeo;
1118 if (ret == 0)
1119 ret = -ETIMEDOUT;
1120 goto out;
1121 }
1122
1123 /*
1124 * By now we've committed to the send. We reuse rds_send_worker()
1125 * to retry sends in the rds thread if the transport asks us to.
1126 */
1127 rds_stats_inc(s_send_queued);
1128
1129 ret = rds_send_xmit(conn);
1130 if (ret == -ENOMEM || ret == -EAGAIN)
1131 queue_delayed_work(rds_wq, &conn->c_send_w, 1);
1132
1133 rds_message_put(rm);
1134 return payload_len;
1135
1136out:
1137 /* If the user included a RDMA_MAP cmsg, we allocated a MR on the fly.
1138 * If the sendmsg goes through, we keep the MR. If it fails with EAGAIN
1139 * or in any other way, we need to destroy the MR again */
1140 if (allocated_mr)
1141 rds_rdma_unuse(rs, rds_rdma_cookie_key(rm->m_rdma_cookie), 1);
1142
1143 if (rm)
1144 rds_message_put(rm);
1145 return ret;
1146}
1147
1148/*
1149 * Reply to a ping packet.
1150 */
1151int
1152rds_send_pong(struct rds_connection *conn, __be16 dport)
1153{
1154 struct rds_message *rm;
1155 unsigned long flags;
1156 int ret = 0;
1157
1158 rm = rds_message_alloc(0, GFP_ATOMIC);
1159 if (!rm) {
1160 ret = -ENOMEM;
1161 goto out;
1162 }
1163
1164 rm->m_daddr = conn->c_faddr;
1165 rm->data.op_active = 1;
1166
1167 rds_conn_connect_if_down(conn);
1168
1169 ret = rds_cong_wait(conn->c_fcong, dport, 1, NULL);
1170 if (ret)
1171 goto out;
1172
1173 spin_lock_irqsave(&conn->c_lock, flags);
1174 list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
1175 set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
1176 rds_message_addref(rm);
1177 rm->m_inc.i_conn = conn;
1178
1179 rds_message_populate_header(&rm->m_inc.i_hdr, 0, dport,
1180 conn->c_next_tx_seq);
1181 conn->c_next_tx_seq++;
1182 spin_unlock_irqrestore(&conn->c_lock, flags);
1183
1184 rds_stats_inc(s_send_queued);
1185 rds_stats_inc(s_send_pong);
1186
1187 /* schedule the send work on rds_wq */
1188 queue_delayed_work(rds_wq, &conn->c_send_w, 1);
1189
1190 rds_message_put(rm);
1191 return 0;
1192
1193out:
1194 if (rm)
1195 rds_message_put(rm);
1196 return ret;
1197}
1/*
2 * Copyright (c) 2006 Oracle. All rights reserved.
3 *
4 * This software is available to you under a choice of one of two
5 * licenses. You may choose to be licensed under the terms of the GNU
6 * General Public License (GPL) Version 2, available from the file
7 * COPYING in the main directory of this source tree, or the
8 * OpenIB.org BSD license below:
9 *
10 * Redistribution and use in source and binary forms, with or
11 * without modification, are permitted provided that the following
12 * conditions are met:
13 *
14 * - Redistributions of source code must retain the above
15 * copyright notice, this list of conditions and the following
16 * disclaimer.
17 *
18 * - Redistributions in binary form must reproduce the above
19 * copyright notice, this list of conditions and the following
20 * disclaimer in the documentation and/or other materials
21 * provided with the distribution.
22 *
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30 * SOFTWARE.
31 *
32 */
33#include <linux/kernel.h>
34#include <linux/moduleparam.h>
35#include <linux/gfp.h>
36#include <net/sock.h>
37#include <linux/in.h>
38#include <linux/list.h>
39#include <linux/ratelimit.h>
40#include <linux/export.h>
41#include <linux/sizes.h>
42
43#include "rds.h"
44
45/* When transmitting messages in rds_send_xmit, we need to emerge from
46 * time to time and briefly release the CPU. Otherwise the softlock watchdog
47 * will kick our shin.
48 * Also, it seems fairer to not let one busy connection stall all the
49 * others.
50 *
51 * send_batch_count is the number of times we'll loop in send_xmit. Setting
52 * it to 0 will restore the old behavior (where we looped until we had
53 * drained the queue).
54 */
55static int send_batch_count = SZ_1K;
56module_param(send_batch_count, int, 0444);
57MODULE_PARM_DESC(send_batch_count, " batch factor when working the send queue");
58
59static void rds_send_remove_from_sock(struct list_head *messages, int status);
60
61/*
62 * Reset the send state. Callers must ensure that this doesn't race with
63 * rds_send_xmit().
64 */
65void rds_send_path_reset(struct rds_conn_path *cp)
66{
67 struct rds_message *rm, *tmp;
68 unsigned long flags;
69
70 if (cp->cp_xmit_rm) {
71 rm = cp->cp_xmit_rm;
72 cp->cp_xmit_rm = NULL;
73 /* Tell the user the RDMA op is no longer mapped by the
74 * transport. This isn't entirely true (it's flushed out
75 * independently) but as the connection is down, there's
76 * no ongoing RDMA to/from that memory */
77 rds_message_unmapped(rm);
78 rds_message_put(rm);
79 }
80
81 cp->cp_xmit_sg = 0;
82 cp->cp_xmit_hdr_off = 0;
83 cp->cp_xmit_data_off = 0;
84 cp->cp_xmit_atomic_sent = 0;
85 cp->cp_xmit_rdma_sent = 0;
86 cp->cp_xmit_data_sent = 0;
87
88 cp->cp_conn->c_map_queued = 0;
89
90 cp->cp_unacked_packets = rds_sysctl_max_unacked_packets;
91 cp->cp_unacked_bytes = rds_sysctl_max_unacked_bytes;
92
93 /* Mark messages as retransmissions, and move them to the send q */
94 spin_lock_irqsave(&cp->cp_lock, flags);
95 list_for_each_entry_safe(rm, tmp, &cp->cp_retrans, m_conn_item) {
96 set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
97 set_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags);
98 }
99 list_splice_init(&cp->cp_retrans, &cp->cp_send_queue);
100 spin_unlock_irqrestore(&cp->cp_lock, flags);
101}
102EXPORT_SYMBOL_GPL(rds_send_path_reset);
103
104static int acquire_in_xmit(struct rds_conn_path *cp)
105{
106 return test_and_set_bit(RDS_IN_XMIT, &cp->cp_flags) == 0;
107}
108
109static void release_in_xmit(struct rds_conn_path *cp)
110{
111 clear_bit(RDS_IN_XMIT, &cp->cp_flags);
112 smp_mb__after_atomic();
113 /*
114 * We don't use wait_on_bit()/wake_up_bit() because our waking is in a
115 * hot path and finding waiters is very rare. We don't want to walk
116 * the system-wide hashed waitqueue buckets in the fast path only to
117 * almost never find waiters.
118 */
119 if (waitqueue_active(&cp->cp_waitq))
120 wake_up_all(&cp->cp_waitq);
121}
122
123/*
124 * We're making the conscious trade-off here to only send one message
125 * down the connection at a time.
126 * Pro:
127 * - tx queueing is a simple fifo list
128 * - reassembly is optional and easily done by transports per conn
129 * - no per flow rx lookup at all, straight to the socket
130 * - less per-frag memory and wire overhead
131 * Con:
132 * - queued acks can be delayed behind large messages
133 * Depends:
134 * - small message latency is higher behind queued large messages
135 * - large message latency isn't starved by intervening small sends
136 */
137int rds_send_xmit(struct rds_conn_path *cp)
138{
139 struct rds_connection *conn = cp->cp_conn;
140 struct rds_message *rm;
141 unsigned long flags;
142 unsigned int tmp;
143 struct scatterlist *sg;
144 int ret = 0;
145 LIST_HEAD(to_be_dropped);
146 int batch_count;
147 unsigned long send_gen = 0;
148
149restart:
150 batch_count = 0;
151
152 /*
153 * sendmsg calls here after having queued its message on the send
154 * queue. We only have one task feeding the connection at a time. If
155 * another thread is already feeding the queue then we back off. This
156 * avoids blocking the caller and trading per-connection data between
157 * caches per message.
158 */
159 if (!acquire_in_xmit(cp)) {
160 rds_stats_inc(s_send_lock_contention);
161 ret = -ENOMEM;
162 goto out;
163 }
164
165 /*
166 * we record the send generation after doing the xmit acquire.
167 * if someone else manages to jump in and do some work, we'll use
168 * this to avoid a goto restart farther down.
169 *
170 * The acquire_in_xmit() check above ensures that only one
171 * caller can increment c_send_gen at any time.
172 */
173 cp->cp_send_gen++;
174 send_gen = cp->cp_send_gen;
175
176 /*
177 * rds_conn_shutdown() sets the conn state and then tests RDS_IN_XMIT,
178 * we do the opposite to avoid races.
179 */
180 if (!rds_conn_path_up(cp)) {
181 release_in_xmit(cp);
182 ret = 0;
183 goto out;
184 }
185
186 if (conn->c_trans->xmit_path_prepare)
187 conn->c_trans->xmit_path_prepare(cp);
188
189 /*
190 * spin trying to push headers and data down the connection until
191 * the connection doesn't make forward progress.
192 */
193 while (1) {
194
195 rm = cp->cp_xmit_rm;
196
197 /*
198 * If between sending messages, we can send a pending congestion
199 * map update.
200 */
201 if (!rm && test_and_clear_bit(0, &conn->c_map_queued)) {
202 rm = rds_cong_update_alloc(conn);
203 if (IS_ERR(rm)) {
204 ret = PTR_ERR(rm);
205 break;
206 }
207 rm->data.op_active = 1;
208 rm->m_inc.i_conn_path = cp;
209 rm->m_inc.i_conn = cp->cp_conn;
210
211 cp->cp_xmit_rm = rm;
212 }
213
214 /*
215 * If not already working on one, grab the next message.
216 *
217 * cp_xmit_rm holds a ref while we're sending this message down
218 * the connction. We can use this ref while holding the
219 * send_sem.. rds_send_reset() is serialized with it.
220 */
221 if (!rm) {
222 unsigned int len;
223
224 batch_count++;
225
226 /* we want to process as big a batch as we can, but
227 * we also want to avoid softlockups. If we've been
228 * through a lot of messages, lets back off and see
229 * if anyone else jumps in
230 */
231 if (batch_count >= send_batch_count)
232 goto over_batch;
233
234 spin_lock_irqsave(&cp->cp_lock, flags);
235
236 if (!list_empty(&cp->cp_send_queue)) {
237 rm = list_entry(cp->cp_send_queue.next,
238 struct rds_message,
239 m_conn_item);
240 rds_message_addref(rm);
241
242 /*
243 * Move the message from the send queue to the retransmit
244 * list right away.
245 */
246 list_move_tail(&rm->m_conn_item,
247 &cp->cp_retrans);
248 }
249
250 spin_unlock_irqrestore(&cp->cp_lock, flags);
251
252 if (!rm)
253 break;
254
255 /* Unfortunately, the way Infiniband deals with
256 * RDMA to a bad MR key is by moving the entire
257 * queue pair to error state. We cold possibly
258 * recover from that, but right now we drop the
259 * connection.
260 * Therefore, we never retransmit messages with RDMA ops.
261 */
262 if (test_bit(RDS_MSG_FLUSH, &rm->m_flags) ||
263 (rm->rdma.op_active &&
264 test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags))) {
265 spin_lock_irqsave(&cp->cp_lock, flags);
266 if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags))
267 list_move(&rm->m_conn_item, &to_be_dropped);
268 spin_unlock_irqrestore(&cp->cp_lock, flags);
269 continue;
270 }
271
272 /* Require an ACK every once in a while */
273 len = ntohl(rm->m_inc.i_hdr.h_len);
274 if (cp->cp_unacked_packets == 0 ||
275 cp->cp_unacked_bytes < len) {
276 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
277
278 cp->cp_unacked_packets =
279 rds_sysctl_max_unacked_packets;
280 cp->cp_unacked_bytes =
281 rds_sysctl_max_unacked_bytes;
282 rds_stats_inc(s_send_ack_required);
283 } else {
284 cp->cp_unacked_bytes -= len;
285 cp->cp_unacked_packets--;
286 }
287
288 cp->cp_xmit_rm = rm;
289 }
290
291 /* The transport either sends the whole rdma or none of it */
292 if (rm->rdma.op_active && !cp->cp_xmit_rdma_sent) {
293 rm->m_final_op = &rm->rdma;
294 /* The transport owns the mapped memory for now.
295 * You can't unmap it while it's on the send queue
296 */
297 set_bit(RDS_MSG_MAPPED, &rm->m_flags);
298 ret = conn->c_trans->xmit_rdma(conn, &rm->rdma);
299 if (ret) {
300 clear_bit(RDS_MSG_MAPPED, &rm->m_flags);
301 wake_up_interruptible(&rm->m_flush_wait);
302 break;
303 }
304 cp->cp_xmit_rdma_sent = 1;
305
306 }
307
308 if (rm->atomic.op_active && !cp->cp_xmit_atomic_sent) {
309 rm->m_final_op = &rm->atomic;
310 /* The transport owns the mapped memory for now.
311 * You can't unmap it while it's on the send queue
312 */
313 set_bit(RDS_MSG_MAPPED, &rm->m_flags);
314 ret = conn->c_trans->xmit_atomic(conn, &rm->atomic);
315 if (ret) {
316 clear_bit(RDS_MSG_MAPPED, &rm->m_flags);
317 wake_up_interruptible(&rm->m_flush_wait);
318 break;
319 }
320 cp->cp_xmit_atomic_sent = 1;
321
322 }
323
324 /*
325 * A number of cases require an RDS header to be sent
326 * even if there is no data.
327 * We permit 0-byte sends; rds-ping depends on this.
328 * However, if there are exclusively attached silent ops,
329 * we skip the hdr/data send, to enable silent operation.
330 */
331 if (rm->data.op_nents == 0) {
332 int ops_present;
333 int all_ops_are_silent = 1;
334
335 ops_present = (rm->atomic.op_active || rm->rdma.op_active);
336 if (rm->atomic.op_active && !rm->atomic.op_silent)
337 all_ops_are_silent = 0;
338 if (rm->rdma.op_active && !rm->rdma.op_silent)
339 all_ops_are_silent = 0;
340
341 if (ops_present && all_ops_are_silent
342 && !rm->m_rdma_cookie)
343 rm->data.op_active = 0;
344 }
345
346 if (rm->data.op_active && !cp->cp_xmit_data_sent) {
347 rm->m_final_op = &rm->data;
348
349 ret = conn->c_trans->xmit(conn, rm,
350 cp->cp_xmit_hdr_off,
351 cp->cp_xmit_sg,
352 cp->cp_xmit_data_off);
353 if (ret <= 0)
354 break;
355
356 if (cp->cp_xmit_hdr_off < sizeof(struct rds_header)) {
357 tmp = min_t(int, ret,
358 sizeof(struct rds_header) -
359 cp->cp_xmit_hdr_off);
360 cp->cp_xmit_hdr_off += tmp;
361 ret -= tmp;
362 }
363
364 sg = &rm->data.op_sg[cp->cp_xmit_sg];
365 while (ret) {
366 tmp = min_t(int, ret, sg->length -
367 cp->cp_xmit_data_off);
368 cp->cp_xmit_data_off += tmp;
369 ret -= tmp;
370 if (cp->cp_xmit_data_off == sg->length) {
371 cp->cp_xmit_data_off = 0;
372 sg++;
373 cp->cp_xmit_sg++;
374 BUG_ON(ret != 0 && cp->cp_xmit_sg ==
375 rm->data.op_nents);
376 }
377 }
378
379 if (cp->cp_xmit_hdr_off == sizeof(struct rds_header) &&
380 (cp->cp_xmit_sg == rm->data.op_nents))
381 cp->cp_xmit_data_sent = 1;
382 }
383
384 /*
385 * A rm will only take multiple times through this loop
386 * if there is a data op. Thus, if the data is sent (or there was
387 * none), then we're done with the rm.
388 */
389 if (!rm->data.op_active || cp->cp_xmit_data_sent) {
390 cp->cp_xmit_rm = NULL;
391 cp->cp_xmit_sg = 0;
392 cp->cp_xmit_hdr_off = 0;
393 cp->cp_xmit_data_off = 0;
394 cp->cp_xmit_rdma_sent = 0;
395 cp->cp_xmit_atomic_sent = 0;
396 cp->cp_xmit_data_sent = 0;
397
398 rds_message_put(rm);
399 }
400 }
401
402over_batch:
403 if (conn->c_trans->xmit_path_complete)
404 conn->c_trans->xmit_path_complete(cp);
405 release_in_xmit(cp);
406
407 /* Nuke any messages we decided not to retransmit. */
408 if (!list_empty(&to_be_dropped)) {
409 /* irqs on here, so we can put(), unlike above */
410 list_for_each_entry(rm, &to_be_dropped, m_conn_item)
411 rds_message_put(rm);
412 rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED);
413 }
414
415 /*
416 * Other senders can queue a message after we last test the send queue
417 * but before we clear RDS_IN_XMIT. In that case they'd back off and
418 * not try and send their newly queued message. We need to check the
419 * send queue after having cleared RDS_IN_XMIT so that their message
420 * doesn't get stuck on the send queue.
421 *
422 * If the transport cannot continue (i.e ret != 0), then it must
423 * call us when more room is available, such as from the tx
424 * completion handler.
425 *
426 * We have an extra generation check here so that if someone manages
427 * to jump in after our release_in_xmit, we'll see that they have done
428 * some work and we will skip our goto
429 */
430 if (ret == 0) {
431 smp_mb();
432 if ((test_bit(0, &conn->c_map_queued) ||
433 !list_empty(&cp->cp_send_queue)) &&
434 send_gen == cp->cp_send_gen) {
435 rds_stats_inc(s_send_lock_queue_raced);
436 if (batch_count < send_batch_count)
437 goto restart;
438 queue_delayed_work(rds_wq, &cp->cp_send_w, 1);
439 }
440 }
441out:
442 return ret;
443}
444EXPORT_SYMBOL_GPL(rds_send_xmit);
445
446static void rds_send_sndbuf_remove(struct rds_sock *rs, struct rds_message *rm)
447{
448 u32 len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
449
450 assert_spin_locked(&rs->rs_lock);
451
452 BUG_ON(rs->rs_snd_bytes < len);
453 rs->rs_snd_bytes -= len;
454
455 if (rs->rs_snd_bytes == 0)
456 rds_stats_inc(s_send_queue_empty);
457}
458
459static inline int rds_send_is_acked(struct rds_message *rm, u64 ack,
460 is_acked_func is_acked)
461{
462 if (is_acked)
463 return is_acked(rm, ack);
464 return be64_to_cpu(rm->m_inc.i_hdr.h_sequence) <= ack;
465}
466
467/*
468 * This is pretty similar to what happens below in the ACK
469 * handling code - except that we call here as soon as we get
470 * the IB send completion on the RDMA op and the accompanying
471 * message.
472 */
473void rds_rdma_send_complete(struct rds_message *rm, int status)
474{
475 struct rds_sock *rs = NULL;
476 struct rm_rdma_op *ro;
477 struct rds_notifier *notifier;
478 unsigned long flags;
479
480 spin_lock_irqsave(&rm->m_rs_lock, flags);
481
482 ro = &rm->rdma;
483 if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) &&
484 ro->op_active && ro->op_notify && ro->op_notifier) {
485 notifier = ro->op_notifier;
486 rs = rm->m_rs;
487 sock_hold(rds_rs_to_sk(rs));
488
489 notifier->n_status = status;
490 spin_lock(&rs->rs_lock);
491 list_add_tail(¬ifier->n_list, &rs->rs_notify_queue);
492 spin_unlock(&rs->rs_lock);
493
494 ro->op_notifier = NULL;
495 }
496
497 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
498
499 if (rs) {
500 rds_wake_sk_sleep(rs);
501 sock_put(rds_rs_to_sk(rs));
502 }
503}
504EXPORT_SYMBOL_GPL(rds_rdma_send_complete);
505
506/*
507 * Just like above, except looks at atomic op
508 */
509void rds_atomic_send_complete(struct rds_message *rm, int status)
510{
511 struct rds_sock *rs = NULL;
512 struct rm_atomic_op *ao;
513 struct rds_notifier *notifier;
514 unsigned long flags;
515
516 spin_lock_irqsave(&rm->m_rs_lock, flags);
517
518 ao = &rm->atomic;
519 if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags)
520 && ao->op_active && ao->op_notify && ao->op_notifier) {
521 notifier = ao->op_notifier;
522 rs = rm->m_rs;
523 sock_hold(rds_rs_to_sk(rs));
524
525 notifier->n_status = status;
526 spin_lock(&rs->rs_lock);
527 list_add_tail(¬ifier->n_list, &rs->rs_notify_queue);
528 spin_unlock(&rs->rs_lock);
529
530 ao->op_notifier = NULL;
531 }
532
533 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
534
535 if (rs) {
536 rds_wake_sk_sleep(rs);
537 sock_put(rds_rs_to_sk(rs));
538 }
539}
540EXPORT_SYMBOL_GPL(rds_atomic_send_complete);
541
542/*
543 * This is the same as rds_rdma_send_complete except we
544 * don't do any locking - we have all the ingredients (message,
545 * socket, socket lock) and can just move the notifier.
546 */
547static inline void
548__rds_send_complete(struct rds_sock *rs, struct rds_message *rm, int status)
549{
550 struct rm_rdma_op *ro;
551 struct rm_atomic_op *ao;
552
553 ro = &rm->rdma;
554 if (ro->op_active && ro->op_notify && ro->op_notifier) {
555 ro->op_notifier->n_status = status;
556 list_add_tail(&ro->op_notifier->n_list, &rs->rs_notify_queue);
557 ro->op_notifier = NULL;
558 }
559
560 ao = &rm->atomic;
561 if (ao->op_active && ao->op_notify && ao->op_notifier) {
562 ao->op_notifier->n_status = status;
563 list_add_tail(&ao->op_notifier->n_list, &rs->rs_notify_queue);
564 ao->op_notifier = NULL;
565 }
566
567 /* No need to wake the app - caller does this */
568}
569
570/*
571 * This removes messages from the socket's list if they're on it. The list
572 * argument must be private to the caller, we must be able to modify it
573 * without locks. The messages must have a reference held for their
574 * position on the list. This function will drop that reference after
575 * removing the messages from the 'messages' list regardless of if it found
576 * the messages on the socket list or not.
577 */
578static void rds_send_remove_from_sock(struct list_head *messages, int status)
579{
580 unsigned long flags;
581 struct rds_sock *rs = NULL;
582 struct rds_message *rm;
583
584 while (!list_empty(messages)) {
585 int was_on_sock = 0;
586
587 rm = list_entry(messages->next, struct rds_message,
588 m_conn_item);
589 list_del_init(&rm->m_conn_item);
590
591 /*
592 * If we see this flag cleared then we're *sure* that someone
593 * else beat us to removing it from the sock. If we race
594 * with their flag update we'll get the lock and then really
595 * see that the flag has been cleared.
596 *
597 * The message spinlock makes sure nobody clears rm->m_rs
598 * while we're messing with it. It does not prevent the
599 * message from being removed from the socket, though.
600 */
601 spin_lock_irqsave(&rm->m_rs_lock, flags);
602 if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags))
603 goto unlock_and_drop;
604
605 if (rs != rm->m_rs) {
606 if (rs) {
607 rds_wake_sk_sleep(rs);
608 sock_put(rds_rs_to_sk(rs));
609 }
610 rs = rm->m_rs;
611 if (rs)
612 sock_hold(rds_rs_to_sk(rs));
613 }
614 if (!rs)
615 goto unlock_and_drop;
616 spin_lock(&rs->rs_lock);
617
618 if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) {
619 struct rm_rdma_op *ro = &rm->rdma;
620 struct rds_notifier *notifier;
621
622 list_del_init(&rm->m_sock_item);
623 rds_send_sndbuf_remove(rs, rm);
624
625 if (ro->op_active && ro->op_notifier &&
626 (ro->op_notify || (ro->op_recverr && status))) {
627 notifier = ro->op_notifier;
628 list_add_tail(¬ifier->n_list,
629 &rs->rs_notify_queue);
630 if (!notifier->n_status)
631 notifier->n_status = status;
632 rm->rdma.op_notifier = NULL;
633 }
634 was_on_sock = 1;
635 rm->m_rs = NULL;
636 }
637 spin_unlock(&rs->rs_lock);
638
639unlock_and_drop:
640 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
641 rds_message_put(rm);
642 if (was_on_sock)
643 rds_message_put(rm);
644 }
645
646 if (rs) {
647 rds_wake_sk_sleep(rs);
648 sock_put(rds_rs_to_sk(rs));
649 }
650}
651
652/*
653 * Transports call here when they've determined that the receiver queued
654 * messages up to, and including, the given sequence number. Messages are
655 * moved to the retrans queue when rds_send_xmit picks them off the send
656 * queue. This means that in the TCP case, the message may not have been
657 * assigned the m_ack_seq yet - but that's fine as long as tcp_is_acked
658 * checks the RDS_MSG_HAS_ACK_SEQ bit.
659 */
660void rds_send_path_drop_acked(struct rds_conn_path *cp, u64 ack,
661 is_acked_func is_acked)
662{
663 struct rds_message *rm, *tmp;
664 unsigned long flags;
665 LIST_HEAD(list);
666
667 spin_lock_irqsave(&cp->cp_lock, flags);
668
669 list_for_each_entry_safe(rm, tmp, &cp->cp_retrans, m_conn_item) {
670 if (!rds_send_is_acked(rm, ack, is_acked))
671 break;
672
673 list_move(&rm->m_conn_item, &list);
674 clear_bit(RDS_MSG_ON_CONN, &rm->m_flags);
675 }
676
677 /* order flag updates with spin locks */
678 if (!list_empty(&list))
679 smp_mb__after_atomic();
680
681 spin_unlock_irqrestore(&cp->cp_lock, flags);
682
683 /* now remove the messages from the sock list as needed */
684 rds_send_remove_from_sock(&list, RDS_RDMA_SUCCESS);
685}
686EXPORT_SYMBOL_GPL(rds_send_path_drop_acked);
687
688void rds_send_drop_acked(struct rds_connection *conn, u64 ack,
689 is_acked_func is_acked)
690{
691 WARN_ON(conn->c_trans->t_mp_capable);
692 rds_send_path_drop_acked(&conn->c_path[0], ack, is_acked);
693}
694EXPORT_SYMBOL_GPL(rds_send_drop_acked);
695
696void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest)
697{
698 struct rds_message *rm, *tmp;
699 struct rds_connection *conn;
700 struct rds_conn_path *cp;
701 unsigned long flags;
702 LIST_HEAD(list);
703
704 /* get all the messages we're dropping under the rs lock */
705 spin_lock_irqsave(&rs->rs_lock, flags);
706
707 list_for_each_entry_safe(rm, tmp, &rs->rs_send_queue, m_sock_item) {
708 if (dest && (dest->sin_addr.s_addr != rm->m_daddr ||
709 dest->sin_port != rm->m_inc.i_hdr.h_dport))
710 continue;
711
712 list_move(&rm->m_sock_item, &list);
713 rds_send_sndbuf_remove(rs, rm);
714 clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
715 }
716
717 /* order flag updates with the rs lock */
718 smp_mb__after_atomic();
719
720 spin_unlock_irqrestore(&rs->rs_lock, flags);
721
722 if (list_empty(&list))
723 return;
724
725 /* Remove the messages from the conn */
726 list_for_each_entry(rm, &list, m_sock_item) {
727
728 conn = rm->m_inc.i_conn;
729 if (conn->c_trans->t_mp_capable)
730 cp = rm->m_inc.i_conn_path;
731 else
732 cp = &conn->c_path[0];
733
734 spin_lock_irqsave(&cp->cp_lock, flags);
735 /*
736 * Maybe someone else beat us to removing rm from the conn.
737 * If we race with their flag update we'll get the lock and
738 * then really see that the flag has been cleared.
739 */
740 if (!test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) {
741 spin_unlock_irqrestore(&cp->cp_lock, flags);
742 spin_lock_irqsave(&rm->m_rs_lock, flags);
743 rm->m_rs = NULL;
744 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
745 continue;
746 }
747 list_del_init(&rm->m_conn_item);
748 spin_unlock_irqrestore(&cp->cp_lock, flags);
749
750 /*
751 * Couldn't grab m_rs_lock in top loop (lock ordering),
752 * but we can now.
753 */
754 spin_lock_irqsave(&rm->m_rs_lock, flags);
755
756 spin_lock(&rs->rs_lock);
757 __rds_send_complete(rs, rm, RDS_RDMA_CANCELED);
758 spin_unlock(&rs->rs_lock);
759
760 rm->m_rs = NULL;
761 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
762
763 rds_message_put(rm);
764 }
765
766 rds_wake_sk_sleep(rs);
767
768 while (!list_empty(&list)) {
769 rm = list_entry(list.next, struct rds_message, m_sock_item);
770 list_del_init(&rm->m_sock_item);
771 rds_message_wait(rm);
772
773 /* just in case the code above skipped this message
774 * because RDS_MSG_ON_CONN wasn't set, run it again here
775 * taking m_rs_lock is the only thing that keeps us
776 * from racing with ack processing.
777 */
778 spin_lock_irqsave(&rm->m_rs_lock, flags);
779
780 spin_lock(&rs->rs_lock);
781 __rds_send_complete(rs, rm, RDS_RDMA_CANCELED);
782 spin_unlock(&rs->rs_lock);
783
784 rm->m_rs = NULL;
785 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
786
787 rds_message_put(rm);
788 }
789}
790
791/*
792 * we only want this to fire once so we use the callers 'queued'. It's
793 * possible that another thread can race with us and remove the
794 * message from the flow with RDS_CANCEL_SENT_TO.
795 */
796static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn,
797 struct rds_conn_path *cp,
798 struct rds_message *rm, __be16 sport,
799 __be16 dport, int *queued)
800{
801 unsigned long flags;
802 u32 len;
803
804 if (*queued)
805 goto out;
806
807 len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
808
809 /* this is the only place which holds both the socket's rs_lock
810 * and the connection's c_lock */
811 spin_lock_irqsave(&rs->rs_lock, flags);
812
813 /*
814 * If there is a little space in sndbuf, we don't queue anything,
815 * and userspace gets -EAGAIN. But poll() indicates there's send
816 * room. This can lead to bad behavior (spinning) if snd_bytes isn't
817 * freed up by incoming acks. So we check the *old* value of
818 * rs_snd_bytes here to allow the last msg to exceed the buffer,
819 * and poll() now knows no more data can be sent.
820 */
821 if (rs->rs_snd_bytes < rds_sk_sndbuf(rs)) {
822 rs->rs_snd_bytes += len;
823
824 /* let recv side know we are close to send space exhaustion.
825 * This is probably not the optimal way to do it, as this
826 * means we set the flag on *all* messages as soon as our
827 * throughput hits a certain threshold.
828 */
829 if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2)
830 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
831
832 list_add_tail(&rm->m_sock_item, &rs->rs_send_queue);
833 set_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
834 rds_message_addref(rm);
835 rm->m_rs = rs;
836
837 /* The code ordering is a little weird, but we're
838 trying to minimize the time we hold c_lock */
839 rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport, 0);
840 rm->m_inc.i_conn = conn;
841 rm->m_inc.i_conn_path = cp;
842 rds_message_addref(rm);
843
844 spin_lock(&cp->cp_lock);
845 rm->m_inc.i_hdr.h_sequence = cpu_to_be64(cp->cp_next_tx_seq++);
846 list_add_tail(&rm->m_conn_item, &cp->cp_send_queue);
847 set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
848 spin_unlock(&cp->cp_lock);
849
850 rdsdebug("queued msg %p len %d, rs %p bytes %d seq %llu\n",
851 rm, len, rs, rs->rs_snd_bytes,
852 (unsigned long long)be64_to_cpu(rm->m_inc.i_hdr.h_sequence));
853
854 *queued = 1;
855 }
856
857 spin_unlock_irqrestore(&rs->rs_lock, flags);
858out:
859 return *queued;
860}
861
862/*
863 * rds_message is getting to be quite complicated, and we'd like to allocate
864 * it all in one go. This figures out how big it needs to be up front.
865 */
866static int rds_rm_size(struct msghdr *msg, int data_len)
867{
868 struct cmsghdr *cmsg;
869 int size = 0;
870 int cmsg_groups = 0;
871 int retval;
872
873 for_each_cmsghdr(cmsg, msg) {
874 if (!CMSG_OK(msg, cmsg))
875 return -EINVAL;
876
877 if (cmsg->cmsg_level != SOL_RDS)
878 continue;
879
880 switch (cmsg->cmsg_type) {
881 case RDS_CMSG_RDMA_ARGS:
882 cmsg_groups |= 1;
883 retval = rds_rdma_extra_size(CMSG_DATA(cmsg));
884 if (retval < 0)
885 return retval;
886 size += retval;
887
888 break;
889
890 case RDS_CMSG_RDMA_DEST:
891 case RDS_CMSG_RDMA_MAP:
892 cmsg_groups |= 2;
893 /* these are valid but do no add any size */
894 break;
895
896 case RDS_CMSG_ATOMIC_CSWP:
897 case RDS_CMSG_ATOMIC_FADD:
898 case RDS_CMSG_MASKED_ATOMIC_CSWP:
899 case RDS_CMSG_MASKED_ATOMIC_FADD:
900 cmsg_groups |= 1;
901 size += sizeof(struct scatterlist);
902 break;
903
904 default:
905 return -EINVAL;
906 }
907
908 }
909
910 size += ceil(data_len, PAGE_SIZE) * sizeof(struct scatterlist);
911
912 /* Ensure (DEST, MAP) are never used with (ARGS, ATOMIC) */
913 if (cmsg_groups == 3)
914 return -EINVAL;
915
916 return size;
917}
918
919static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
920 struct msghdr *msg, int *allocated_mr)
921{
922 struct cmsghdr *cmsg;
923 int ret = 0;
924
925 for_each_cmsghdr(cmsg, msg) {
926 if (!CMSG_OK(msg, cmsg))
927 return -EINVAL;
928
929 if (cmsg->cmsg_level != SOL_RDS)
930 continue;
931
932 /* As a side effect, RDMA_DEST and RDMA_MAP will set
933 * rm->rdma.m_rdma_cookie and rm->rdma.m_rdma_mr.
934 */
935 switch (cmsg->cmsg_type) {
936 case RDS_CMSG_RDMA_ARGS:
937 ret = rds_cmsg_rdma_args(rs, rm, cmsg);
938 break;
939
940 case RDS_CMSG_RDMA_DEST:
941 ret = rds_cmsg_rdma_dest(rs, rm, cmsg);
942 break;
943
944 case RDS_CMSG_RDMA_MAP:
945 ret = rds_cmsg_rdma_map(rs, rm, cmsg);
946 if (!ret)
947 *allocated_mr = 1;
948 break;
949 case RDS_CMSG_ATOMIC_CSWP:
950 case RDS_CMSG_ATOMIC_FADD:
951 case RDS_CMSG_MASKED_ATOMIC_CSWP:
952 case RDS_CMSG_MASKED_ATOMIC_FADD:
953 ret = rds_cmsg_atomic(rs, rm, cmsg);
954 break;
955
956 default:
957 return -EINVAL;
958 }
959
960 if (ret)
961 break;
962 }
963
964 return ret;
965}
966
967static void rds_send_ping(struct rds_connection *conn);
968
969static int rds_send_mprds_hash(struct rds_sock *rs, struct rds_connection *conn)
970{
971 int hash;
972
973 if (conn->c_npaths == 0)
974 hash = RDS_MPATH_HASH(rs, RDS_MPATH_WORKERS);
975 else
976 hash = RDS_MPATH_HASH(rs, conn->c_npaths);
977 if (conn->c_npaths == 0 && hash != 0) {
978 rds_send_ping(conn);
979
980 if (conn->c_npaths == 0) {
981 wait_event_interruptible(conn->c_hs_waitq,
982 (conn->c_npaths != 0));
983 }
984 if (conn->c_npaths == 1)
985 hash = 0;
986 }
987 return hash;
988}
989
990int rds_sendmsg(struct socket *sock, struct msghdr *msg, size_t payload_len)
991{
992 struct sock *sk = sock->sk;
993 struct rds_sock *rs = rds_sk_to_rs(sk);
994 DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
995 __be32 daddr;
996 __be16 dport;
997 struct rds_message *rm = NULL;
998 struct rds_connection *conn;
999 int ret = 0;
1000 int queued = 0, allocated_mr = 0;
1001 int nonblock = msg->msg_flags & MSG_DONTWAIT;
1002 long timeo = sock_sndtimeo(sk, nonblock);
1003 struct rds_conn_path *cpath;
1004
1005 /* Mirror Linux UDP mirror of BSD error message compatibility */
1006 /* XXX: Perhaps MSG_MORE someday */
1007 if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) {
1008 ret = -EOPNOTSUPP;
1009 goto out;
1010 }
1011
1012 if (msg->msg_namelen) {
1013 /* XXX fail non-unicast destination IPs? */
1014 if (msg->msg_namelen < sizeof(*usin) || usin->sin_family != AF_INET) {
1015 ret = -EINVAL;
1016 goto out;
1017 }
1018 daddr = usin->sin_addr.s_addr;
1019 dport = usin->sin_port;
1020 } else {
1021 /* We only care about consistency with ->connect() */
1022 lock_sock(sk);
1023 daddr = rs->rs_conn_addr;
1024 dport = rs->rs_conn_port;
1025 release_sock(sk);
1026 }
1027
1028 lock_sock(sk);
1029 if (daddr == 0 || rs->rs_bound_addr == 0) {
1030 release_sock(sk);
1031 ret = -ENOTCONN; /* XXX not a great errno */
1032 goto out;
1033 }
1034 release_sock(sk);
1035
1036 if (payload_len > rds_sk_sndbuf(rs)) {
1037 ret = -EMSGSIZE;
1038 goto out;
1039 }
1040
1041 /* size of rm including all sgs */
1042 ret = rds_rm_size(msg, payload_len);
1043 if (ret < 0)
1044 goto out;
1045
1046 rm = rds_message_alloc(ret, GFP_KERNEL);
1047 if (!rm) {
1048 ret = -ENOMEM;
1049 goto out;
1050 }
1051
1052 /* Attach data to the rm */
1053 if (payload_len) {
1054 rm->data.op_sg = rds_message_alloc_sgs(rm, ceil(payload_len, PAGE_SIZE));
1055 if (!rm->data.op_sg) {
1056 ret = -ENOMEM;
1057 goto out;
1058 }
1059 ret = rds_message_copy_from_user(rm, &msg->msg_iter);
1060 if (ret)
1061 goto out;
1062 }
1063 rm->data.op_active = 1;
1064
1065 rm->m_daddr = daddr;
1066
1067 /* rds_conn_create has a spinlock that runs with IRQ off.
1068 * Caching the conn in the socket helps a lot. */
1069 if (rs->rs_conn && rs->rs_conn->c_faddr == daddr)
1070 conn = rs->rs_conn;
1071 else {
1072 conn = rds_conn_create_outgoing(sock_net(sock->sk),
1073 rs->rs_bound_addr, daddr,
1074 rs->rs_transport,
1075 sock->sk->sk_allocation);
1076 if (IS_ERR(conn)) {
1077 ret = PTR_ERR(conn);
1078 goto out;
1079 }
1080 rs->rs_conn = conn;
1081 }
1082
1083 /* Parse any control messages the user may have included. */
1084 ret = rds_cmsg_send(rs, rm, msg, &allocated_mr);
1085 if (ret)
1086 goto out;
1087
1088 if (rm->rdma.op_active && !conn->c_trans->xmit_rdma) {
1089 printk_ratelimited(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",
1090 &rm->rdma, conn->c_trans->xmit_rdma);
1091 ret = -EOPNOTSUPP;
1092 goto out;
1093 }
1094
1095 if (rm->atomic.op_active && !conn->c_trans->xmit_atomic) {
1096 printk_ratelimited(KERN_NOTICE "atomic_op %p conn xmit_atomic %p\n",
1097 &rm->atomic, conn->c_trans->xmit_atomic);
1098 ret = -EOPNOTSUPP;
1099 goto out;
1100 }
1101
1102 if (conn->c_trans->t_mp_capable)
1103 cpath = &conn->c_path[rds_send_mprds_hash(rs, conn)];
1104 else
1105 cpath = &conn->c_path[0];
1106
1107 rds_conn_path_connect_if_down(cpath);
1108
1109 ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);
1110 if (ret) {
1111 rs->rs_seen_congestion = 1;
1112 goto out;
1113 }
1114 while (!rds_send_queue_rm(rs, conn, cpath, rm, rs->rs_bound_port,
1115 dport, &queued)) {
1116 rds_stats_inc(s_send_queue_full);
1117
1118 if (nonblock) {
1119 ret = -EAGAIN;
1120 goto out;
1121 }
1122
1123 timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
1124 rds_send_queue_rm(rs, conn, cpath, rm,
1125 rs->rs_bound_port,
1126 dport,
1127 &queued),
1128 timeo);
1129 rdsdebug("sendmsg woke queued %d timeo %ld\n", queued, timeo);
1130 if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
1131 continue;
1132
1133 ret = timeo;
1134 if (ret == 0)
1135 ret = -ETIMEDOUT;
1136 goto out;
1137 }
1138
1139 /*
1140 * By now we've committed to the send. We reuse rds_send_worker()
1141 * to retry sends in the rds thread if the transport asks us to.
1142 */
1143 rds_stats_inc(s_send_queued);
1144
1145 ret = rds_send_xmit(cpath);
1146 if (ret == -ENOMEM || ret == -EAGAIN)
1147 queue_delayed_work(rds_wq, &cpath->cp_send_w, 1);
1148
1149 rds_message_put(rm);
1150 return payload_len;
1151
1152out:
1153 /* If the user included a RDMA_MAP cmsg, we allocated a MR on the fly.
1154 * If the sendmsg goes through, we keep the MR. If it fails with EAGAIN
1155 * or in any other way, we need to destroy the MR again */
1156 if (allocated_mr)
1157 rds_rdma_unuse(rs, rds_rdma_cookie_key(rm->m_rdma_cookie), 1);
1158
1159 if (rm)
1160 rds_message_put(rm);
1161 return ret;
1162}
1163
1164/*
1165 * send out a probe. Can be shared by rds_send_ping,
1166 * rds_send_pong, rds_send_hb.
1167 * rds_send_hb should use h_flags
1168 * RDS_FLAG_HB_PING|RDS_FLAG_ACK_REQUIRED
1169 * or
1170 * RDS_FLAG_HB_PONG|RDS_FLAG_ACK_REQUIRED
1171 */
1172int
1173rds_send_probe(struct rds_conn_path *cp, __be16 sport,
1174 __be16 dport, u8 h_flags)
1175{
1176 struct rds_message *rm;
1177 unsigned long flags;
1178 int ret = 0;
1179
1180 rm = rds_message_alloc(0, GFP_ATOMIC);
1181 if (!rm) {
1182 ret = -ENOMEM;
1183 goto out;
1184 }
1185
1186 rm->m_daddr = cp->cp_conn->c_faddr;
1187 rm->data.op_active = 1;
1188
1189 rds_conn_path_connect_if_down(cp);
1190
1191 ret = rds_cong_wait(cp->cp_conn->c_fcong, dport, 1, NULL);
1192 if (ret)
1193 goto out;
1194
1195 spin_lock_irqsave(&cp->cp_lock, flags);
1196 list_add_tail(&rm->m_conn_item, &cp->cp_send_queue);
1197 set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
1198 rds_message_addref(rm);
1199 rm->m_inc.i_conn = cp->cp_conn;
1200 rm->m_inc.i_conn_path = cp;
1201
1202 rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport,
1203 cp->cp_next_tx_seq);
1204 rm->m_inc.i_hdr.h_flags |= h_flags;
1205 cp->cp_next_tx_seq++;
1206
1207 if (RDS_HS_PROBE(sport, dport) && cp->cp_conn->c_trans->t_mp_capable) {
1208 u16 npaths = RDS_MPATH_WORKERS;
1209
1210 rds_message_add_extension(&rm->m_inc.i_hdr,
1211 RDS_EXTHDR_NPATHS, &npaths,
1212 sizeof(npaths));
1213 rds_message_add_extension(&rm->m_inc.i_hdr,
1214 RDS_EXTHDR_GEN_NUM,
1215 &cp->cp_conn->c_my_gen_num,
1216 sizeof(u32));
1217 }
1218 spin_unlock_irqrestore(&cp->cp_lock, flags);
1219
1220 rds_stats_inc(s_send_queued);
1221 rds_stats_inc(s_send_pong);
1222
1223 /* schedule the send work on rds_wq */
1224 queue_delayed_work(rds_wq, &cp->cp_send_w, 1);
1225
1226 rds_message_put(rm);
1227 return 0;
1228
1229out:
1230 if (rm)
1231 rds_message_put(rm);
1232 return ret;
1233}
1234
1235int
1236rds_send_pong(struct rds_conn_path *cp, __be16 dport)
1237{
1238 return rds_send_probe(cp, 0, dport, 0);
1239}
1240
1241void
1242rds_send_ping(struct rds_connection *conn)
1243{
1244 unsigned long flags;
1245 struct rds_conn_path *cp = &conn->c_path[0];
1246
1247 spin_lock_irqsave(&cp->cp_lock, flags);
1248 if (conn->c_ping_triggered) {
1249 spin_unlock_irqrestore(&cp->cp_lock, flags);
1250 return;
1251 }
1252 conn->c_ping_triggered = 1;
1253 spin_unlock_irqrestore(&cp->cp_lock, flags);
1254 rds_send_probe(&conn->c_path[0], RDS_FLAG_PROBE_PORT, 0, 0);
1255}