437f1e72609c612c7c140e95724556bd3edf8bde
[linux-2.6.git] / net / rds / send.c
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/gfp.h>
35 #include <net/sock.h>
36 #include <linux/in.h>
37 #include <linux/list.h>
38
39 #include "rds.h"
40
41 /* When transmitting messages in rds_send_xmit, we need to emerge from
42  * time to time and briefly release the CPU. Otherwise the softlock watchdog
43  * will kick our shin.
44  * Also, it seems fairer to not let one busy connection stall all the
45  * others.
46  *
47  * send_batch_count is the number of times we'll loop in send_xmit. Setting
48  * it to 0 will restore the old behavior (where we looped until we had
49  * drained the queue).
50  */
51 static int send_batch_count = 64;
52 module_param(send_batch_count, int, 0444);
53 MODULE_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  */
58 void rds_send_reset(struct rds_connection *conn)
59 {
60         struct rds_message *rm, *tmp;
61         unsigned long flags;
62
63         spin_lock_irqsave(&conn->c_send_lock, flags);
64         if (conn->c_xmit_rm) {
65                 rm = conn->c_xmit_rm;
66                 conn->c_xmit_rm = NULL;
67                 /* Tell the user the RDMA op is no longer mapped by the
68                  * transport. This isn't entirely true (it's flushed out
69                  * independently) but as the connection is down, there's
70                  * no ongoing RDMA to/from that memory */
71                 rds_message_unmapped(rm);
72                 spin_unlock_irqrestore(&conn->c_send_lock, flags);
73
74                 rds_message_put(rm);
75         } else {
76                 spin_unlock_irqrestore(&conn->c_send_lock, flags);
77         }
78
79         conn->c_xmit_sg = 0;
80         conn->c_xmit_hdr_off = 0;
81         conn->c_xmit_data_off = 0;
82         conn->c_xmit_atomic_sent = 0;
83         conn->c_xmit_rdma_sent = 0;
84         conn->c_xmit_data_sent = 0;
85
86         conn->c_map_queued = 0;
87
88         conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
89         conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
90
91         /* Mark messages as retransmissions, and move them to the send q */
92         spin_lock_irqsave(&conn->c_lock, flags);
93         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
94                 set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
95                 set_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags);
96         }
97         list_splice_init(&conn->c_retrans, &conn->c_send_queue);
98         spin_unlock_irqrestore(&conn->c_lock, flags);
99 }
100
101 /*
102  * We're making the concious trade-off here to only send one message
103  * down the connection at a time.
104  *   Pro:
105  *      - tx queueing is a simple fifo list
106  *      - reassembly is optional and easily done by transports per conn
107  *      - no per flow rx lookup at all, straight to the socket
108  *      - less per-frag memory and wire overhead
109  *   Con:
110  *      - queued acks can be delayed behind large messages
111  *   Depends:
112  *      - small message latency is higher behind queued large messages
113  *      - large message latency isn't starved by intervening small sends
114  */
115 int rds_send_xmit(struct rds_connection *conn)
116 {
117         struct rds_message *rm;
118         unsigned long flags;
119         unsigned int tmp;
120         struct scatterlist *sg;
121         int ret = 0;
122         int gen = 0;
123         LIST_HEAD(to_be_dropped);
124
125 restart:
126         if (!rds_conn_up(conn))
127                 goto out;
128
129         /*
130          * sendmsg calls here after having queued its message on the send
131          * queue.  We only have one task feeding the connection at a time.  If
132          * another thread is already feeding the queue then we back off.  This
133          * avoids blocking the caller and trading per-connection data between
134          * caches per message.
135          */
136         if (!spin_trylock_irqsave(&conn->c_send_lock, flags)) {
137                 rds_stats_inc(s_send_lock_contention);
138                 ret = -ENOMEM;
139                 goto out;
140         }
141         atomic_inc(&conn->c_senders);
142
143         if (conn->c_trans->xmit_prepare)
144                 conn->c_trans->xmit_prepare(conn);
145
146         gen = atomic_inc_return(&conn->c_send_generation);
147
148         /*
149          * spin trying to push headers and data down the connection until
150          * the connection doesn't make forward progress.
151          */
152         while (1) {
153
154                 rm = conn->c_xmit_rm;
155
156                 /*
157                  * If between sending messages, we can send a pending congestion
158                  * map update.
159                  */
160                 if (!rm && test_and_clear_bit(0, &conn->c_map_queued)) {
161                         rm = rds_cong_update_alloc(conn);
162                         if (IS_ERR(rm)) {
163                                 ret = PTR_ERR(rm);
164                                 break;
165                         }
166                         rm->data.op_active = 1;
167
168                         conn->c_xmit_rm = rm;
169                 }
170
171                 /*
172                  * If not already working on one, grab the next message.
173                  *
174                  * c_xmit_rm holds a ref while we're sending this message down
175                  * the connction.  We can use this ref while holding the
176                  * send_sem.. rds_send_reset() is serialized with it.
177                  */
178                 if (!rm) {
179                         unsigned int len;
180
181                         spin_lock(&conn->c_lock);
182
183                         if (!list_empty(&conn->c_send_queue)) {
184                                 rm = list_entry(conn->c_send_queue.next,
185                                                 struct rds_message,
186                                                 m_conn_item);
187                                 rds_message_addref(rm);
188
189                                 /*
190                                  * Move the message from the send queue to the retransmit
191                                  * list right away.
192                                  */
193                                 list_move_tail(&rm->m_conn_item, &conn->c_retrans);
194                         }
195
196                         spin_unlock(&conn->c_lock);
197
198                         if (!rm)
199                                 break;
200
201                         /* Unfortunately, the way Infiniband deals with
202                          * RDMA to a bad MR key is by moving the entire
203                          * queue pair to error state. We cold possibly
204                          * recover from that, but right now we drop the
205                          * connection.
206                          * Therefore, we never retransmit messages with RDMA ops.
207                          */
208                         if (rm->rdma.op_active &&
209                             test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) {
210                                 spin_lock(&conn->c_lock);
211                                 if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags))
212                                         list_move(&rm->m_conn_item, &to_be_dropped);
213                                 spin_unlock(&conn->c_lock);
214                                 continue;
215                         }
216
217                         /* Require an ACK every once in a while */
218                         len = ntohl(rm->m_inc.i_hdr.h_len);
219                         if (conn->c_unacked_packets == 0 ||
220                             conn->c_unacked_bytes < len) {
221                                 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
222
223                                 conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
224                                 conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
225                                 rds_stats_inc(s_send_ack_required);
226                         } else {
227                                 conn->c_unacked_bytes -= len;
228                                 conn->c_unacked_packets--;
229                         }
230
231                         conn->c_xmit_rm = rm;
232                 }
233
234                 /* The transport either sends the whole rdma or none of it */
235                 if (rm->rdma.op_active && !conn->c_xmit_rdma_sent) {
236                         rm->m_final_op = &rm->rdma;
237                         ret = conn->c_trans->xmit_rdma(conn, &rm->rdma);
238                         if (ret)
239                                 break;
240                         conn->c_xmit_rdma_sent = 1;
241
242                         /* The transport owns the mapped memory for now.
243                          * You can't unmap it while it's on the send queue */
244                         set_bit(RDS_MSG_MAPPED, &rm->m_flags);
245                 }
246
247                 if (rm->atomic.op_active && !conn->c_xmit_atomic_sent) {
248                         rm->m_final_op = &rm->atomic;
249                         ret = conn->c_trans->xmit_atomic(conn, &rm->atomic);
250                         if (ret)
251                                 break;
252                         conn->c_xmit_atomic_sent = 1;
253
254                         /* The transport owns the mapped memory for now.
255                          * You can't unmap it while it's on the send queue */
256                         set_bit(RDS_MSG_MAPPED, &rm->m_flags);
257                 }
258
259                 /*
260                  * A number of cases require an RDS header to be sent
261                  * even if there is no data.
262                  * We permit 0-byte sends; rds-ping depends on this.
263                  * However, if there are exclusively attached silent ops,
264                  * we skip the hdr/data send, to enable silent operation.
265                  */
266                 if (rm->data.op_nents == 0) {
267                         int ops_present;
268                         int all_ops_are_silent = 1;
269
270                         ops_present = (rm->atomic.op_active || rm->rdma.op_active);
271                         if (rm->atomic.op_active && !rm->atomic.op_silent)
272                                 all_ops_are_silent = 0;
273                         if (rm->rdma.op_active && !rm->rdma.op_silent)
274                                 all_ops_are_silent = 0;
275
276                         if (ops_present && all_ops_are_silent
277                             && !rm->m_rdma_cookie)
278                                 rm->data.op_active = 0;
279                 }
280
281                 if (rm->data.op_active && !conn->c_xmit_data_sent) {
282                         rm->m_final_op = &rm->data;
283                         ret = conn->c_trans->xmit(conn, rm,
284                                                   conn->c_xmit_hdr_off,
285                                                   conn->c_xmit_sg,
286                                                   conn->c_xmit_data_off);
287                         if (ret <= 0)
288                                 break;
289
290                         if (conn->c_xmit_hdr_off < sizeof(struct rds_header)) {
291                                 tmp = min_t(int, ret,
292                                             sizeof(struct rds_header) -
293                                             conn->c_xmit_hdr_off);
294                                 conn->c_xmit_hdr_off += tmp;
295                                 ret -= tmp;
296                         }
297
298                         sg = &rm->data.op_sg[conn->c_xmit_sg];
299                         while (ret) {
300                                 tmp = min_t(int, ret, sg->length -
301                                                       conn->c_xmit_data_off);
302                                 conn->c_xmit_data_off += tmp;
303                                 ret -= tmp;
304                                 if (conn->c_xmit_data_off == sg->length) {
305                                         conn->c_xmit_data_off = 0;
306                                         sg++;
307                                         conn->c_xmit_sg++;
308                                         BUG_ON(ret != 0 &&
309                                                conn->c_xmit_sg == rm->data.op_nents);
310                                 }
311                         }
312
313                         if (conn->c_xmit_hdr_off == sizeof(struct rds_header) &&
314                             (conn->c_xmit_sg == rm->data.op_nents))
315                                 conn->c_xmit_data_sent = 1;
316                 }
317
318                 /*
319                  * A rm will only take multiple times through this loop
320                  * if there is a data op. Thus, if the data is sent (or there was
321                  * none), then we're done with the rm.
322                  */
323                 if (!rm->data.op_active || conn->c_xmit_data_sent) {
324                         conn->c_xmit_rm = NULL;
325                         conn->c_xmit_sg = 0;
326                         conn->c_xmit_hdr_off = 0;
327                         conn->c_xmit_data_off = 0;
328                         conn->c_xmit_rdma_sent = 0;
329                         conn->c_xmit_atomic_sent = 0;
330                         conn->c_xmit_data_sent = 0;
331
332                         rds_message_put(rm);
333                 }
334         }
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         spin_unlock_irqrestore(&conn->c_send_lock, flags);
352
353         /* Nuke any messages we decided not to retransmit. */
354         if (!list_empty(&to_be_dropped)) {
355                 /* irqs on here, so we can put(), unlike above */
356                 list_for_each_entry(rm, &to_be_dropped, m_conn_item)
357                         rds_message_put(rm);
358                 rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED);
359         }
360
361         atomic_dec(&conn->c_senders);
362
363         /*
364          * Other senders will see we have c_send_lock and exit. We
365          * need to recheck the send queue and race again for c_send_lock
366          * to make sure messages don't just sit on the send queue, if
367          * somebody hasn't already beat us into the loop.
368          *
369          * If the transport cannot continue (i.e ret != 0), then it must
370          * call us when more room is available, such as from the tx
371          * completion handler.
372          */
373         if (ret == 0) {
374                 smp_mb();
375                 if (!list_empty(&conn->c_send_queue)) {
376                         rds_stats_inc(s_send_lock_queue_raced);
377                         if (gen == atomic_read(&conn->c_send_generation)) {
378                                 goto restart;
379                         }
380                 }
381         }
382 out:
383         return ret;
384 }
385
386 static void rds_send_sndbuf_remove(struct rds_sock *rs, struct rds_message *rm)
387 {
388         u32 len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
389
390         assert_spin_locked(&rs->rs_lock);
391
392         BUG_ON(rs->rs_snd_bytes < len);
393         rs->rs_snd_bytes -= len;
394
395         if (rs->rs_snd_bytes == 0)
396                 rds_stats_inc(s_send_queue_empty);
397 }
398
399 static inline int rds_send_is_acked(struct rds_message *rm, u64 ack,
400                                     is_acked_func is_acked)
401 {
402         if (is_acked)
403                 return is_acked(rm, ack);
404         return be64_to_cpu(rm->m_inc.i_hdr.h_sequence) <= ack;
405 }
406
407 /*
408  * Returns true if there are no messages on the send and retransmit queues
409  * which have a sequence number greater than or equal to the given sequence
410  * number.
411  */
412 int rds_send_acked_before(struct rds_connection *conn, u64 seq)
413 {
414         struct rds_message *rm, *tmp;
415         int ret = 1;
416
417         spin_lock(&conn->c_lock);
418
419         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
420                 if (be64_to_cpu(rm->m_inc.i_hdr.h_sequence) < seq)
421                         ret = 0;
422                 break;
423         }
424
425         list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
426                 if (be64_to_cpu(rm->m_inc.i_hdr.h_sequence) < seq)
427                         ret = 0;
428                 break;
429         }
430
431         spin_unlock(&conn->c_lock);
432
433         return ret;
434 }
435
436 /*
437  * This is pretty similar to what happens below in the ACK
438  * handling code - except that we call here as soon as we get
439  * the IB send completion on the RDMA op and the accompanying
440  * message.
441  */
442 void rds_rdma_send_complete(struct rds_message *rm, int status)
443 {
444         struct rds_sock *rs = NULL;
445         struct rm_rdma_op *ro;
446         struct rds_notifier *notifier;
447         unsigned long flags;
448
449         spin_lock_irqsave(&rm->m_rs_lock, flags);
450
451         ro = &rm->rdma;
452         if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) &&
453             ro->op_active && ro->op_notify && ro->op_notifier) {
454                 notifier = ro->op_notifier;
455                 rs = rm->m_rs;
456                 sock_hold(rds_rs_to_sk(rs));
457
458                 notifier->n_status = status;
459                 spin_lock(&rs->rs_lock);
460                 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
461                 spin_unlock(&rs->rs_lock);
462
463                 ro->op_notifier = NULL;
464         }
465
466         spin_unlock_irqrestore(&rm->m_rs_lock, flags);
467
468         if (rs) {
469                 rds_wake_sk_sleep(rs);
470                 sock_put(rds_rs_to_sk(rs));
471         }
472 }
473 EXPORT_SYMBOL_GPL(rds_rdma_send_complete);
474
475 /*
476  * Just like above, except looks at atomic op
477  */
478 void rds_atomic_send_complete(struct rds_message *rm, int status)
479 {
480         struct rds_sock *rs = NULL;
481         struct rm_atomic_op *ao;
482         struct rds_notifier *notifier;
483         unsigned long flags;
484
485         spin_lock_irqsave(&rm->m_rs_lock, flags);
486
487         ao = &rm->atomic;
488         if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags)
489             && ao->op_active && ao->op_notify && ao->op_notifier) {
490                 notifier = ao->op_notifier;
491                 rs = rm->m_rs;
492                 sock_hold(rds_rs_to_sk(rs));
493
494                 notifier->n_status = status;
495                 spin_lock(&rs->rs_lock);
496                 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
497                 spin_unlock(&rs->rs_lock);
498
499                 ao->op_notifier = NULL;
500         }
501
502         spin_unlock_irqrestore(&rm->m_rs_lock, flags);
503
504         if (rs) {
505                 rds_wake_sk_sleep(rs);
506                 sock_put(rds_rs_to_sk(rs));
507         }
508 }
509 EXPORT_SYMBOL_GPL(rds_atomic_send_complete);
510
511 /*
512  * This is the same as rds_rdma_send_complete except we
513  * don't do any locking - we have all the ingredients (message,
514  * socket, socket lock) and can just move the notifier.
515  */
516 static inline void
517 __rds_send_complete(struct rds_sock *rs, struct rds_message *rm, int status)
518 {
519         struct rm_rdma_op *ro;
520         struct rm_atomic_op *ao;
521
522         ro = &rm->rdma;
523         if (ro->op_active && ro->op_notify && ro->op_notifier) {
524                 ro->op_notifier->n_status = status;
525                 list_add_tail(&ro->op_notifier->n_list, &rs->rs_notify_queue);
526                 ro->op_notifier = NULL;
527         }
528
529         ao = &rm->atomic;
530         if (ao->op_active && ao->op_notify && ao->op_notifier) {
531                 ao->op_notifier->n_status = status;
532                 list_add_tail(&ao->op_notifier->n_list, &rs->rs_notify_queue);
533                 ao->op_notifier = NULL;
534         }
535
536         /* No need to wake the app - caller does this */
537 }
538
539 /*
540  * This is called from the IB send completion when we detect
541  * a RDMA operation that failed with remote access error.
542  * So speed is not an issue here.
543  */
544 struct rds_message *rds_send_get_message(struct rds_connection *conn,
545                                          struct rm_rdma_op *op)
546 {
547         struct rds_message *rm, *tmp, *found = NULL;
548         unsigned long flags;
549
550         spin_lock_irqsave(&conn->c_lock, flags);
551
552         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
553                 if (&rm->rdma == op) {
554                         atomic_inc(&rm->m_refcount);
555                         found = rm;
556                         goto out;
557                 }
558         }
559
560         list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
561                 if (&rm->rdma == op) {
562                         atomic_inc(&rm->m_refcount);
563                         found = rm;
564                         break;
565                 }
566         }
567
568 out:
569         spin_unlock_irqrestore(&conn->c_lock, flags);
570
571         return found;
572 }
573 EXPORT_SYMBOL_GPL(rds_send_get_message);
574
575 /*
576  * This removes messages from the socket's list if they're on it.  The list
577  * argument must be private to the caller, we must be able to modify it
578  * without locks.  The messages must have a reference held for their
579  * position on the list.  This function will drop that reference after
580  * removing the messages from the 'messages' list regardless of if it found
581  * the messages on the socket list or not.
582  */
583 void rds_send_remove_from_sock(struct list_head *messages, int status)
584 {
585         unsigned long flags;
586         struct rds_sock *rs = NULL;
587         struct rds_message *rm;
588
589         while (!list_empty(messages)) {
590                 int was_on_sock = 0;
591
592                 rm = list_entry(messages->next, struct rds_message,
593                                 m_conn_item);
594                 list_del_init(&rm->m_conn_item);
595
596                 /*
597                  * If we see this flag cleared then we're *sure* that someone
598                  * else beat us to removing it from the sock.  If we race
599                  * with their flag update we'll get the lock and then really
600                  * see that the flag has been cleared.
601                  *
602                  * The message spinlock makes sure nobody clears rm->m_rs
603                  * while we're messing with it. It does not prevent the
604                  * message from being removed from the socket, though.
605                  */
606                 spin_lock_irqsave(&rm->m_rs_lock, flags);
607                 if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags))
608                         goto unlock_and_drop;
609
610                 if (rs != rm->m_rs) {
611                         if (rs) {
612                                 rds_wake_sk_sleep(rs);
613                                 sock_put(rds_rs_to_sk(rs));
614                         }
615                         rs = rm->m_rs;
616                         sock_hold(rds_rs_to_sk(rs));
617                 }
618                 spin_lock(&rs->rs_lock);
619
620                 if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) {
621                         struct rm_rdma_op *ro = &rm->rdma;
622                         struct rds_notifier *notifier;
623
624                         list_del_init(&rm->m_sock_item);
625                         rds_send_sndbuf_remove(rs, rm);
626
627                         if (ro->op_active && ro->op_notifier &&
628                                (ro->op_notify || (ro->op_recverr && status))) {
629                                 notifier = ro->op_notifier;
630                                 list_add_tail(&notifier->n_list,
631                                                 &rs->rs_notify_queue);
632                                 if (!notifier->n_status)
633                                         notifier->n_status = status;
634                                 rm->rdma.op_notifier = NULL;
635                         }
636                         was_on_sock = 1;
637                         rm->m_rs = NULL;
638                 }
639                 spin_unlock(&rs->rs_lock);
640
641 unlock_and_drop:
642                 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
643                 rds_message_put(rm);
644                 if (was_on_sock)
645                         rds_message_put(rm);
646         }
647
648         if (rs) {
649                 rds_wake_sk_sleep(rs);
650                 sock_put(rds_rs_to_sk(rs));
651         }
652 }
653
654 /*
655  * Transports call here when they've determined that the receiver queued
656  * messages up to, and including, the given sequence number.  Messages are
657  * moved to the retrans queue when rds_send_xmit picks them off the send
658  * queue. This means that in the TCP case, the message may not have been
659  * assigned the m_ack_seq yet - but that's fine as long as tcp_is_acked
660  * checks the RDS_MSG_HAS_ACK_SEQ bit.
661  *
662  * XXX It's not clear to me how this is safely serialized with socket
663  * destruction.  Maybe it should bail if it sees SOCK_DEAD.
664  */
665 void rds_send_drop_acked(struct rds_connection *conn, u64 ack,
666                          is_acked_func is_acked)
667 {
668         struct rds_message *rm, *tmp;
669         unsigned long flags;
670         LIST_HEAD(list);
671
672         spin_lock_irqsave(&conn->c_lock, flags);
673
674         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
675                 if (!rds_send_is_acked(rm, ack, is_acked))
676                         break;
677
678                 list_move(&rm->m_conn_item, &list);
679                 clear_bit(RDS_MSG_ON_CONN, &rm->m_flags);
680         }
681
682         /* order flag updates with spin locks */
683         if (!list_empty(&list))
684                 smp_mb__after_clear_bit();
685
686         spin_unlock_irqrestore(&conn->c_lock, flags);
687
688         /* now remove the messages from the sock list as needed */
689         rds_send_remove_from_sock(&list, RDS_RDMA_SUCCESS);
690 }
691 EXPORT_SYMBOL_GPL(rds_send_drop_acked);
692
693 void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest)
694 {
695         struct rds_message *rm, *tmp;
696         struct rds_connection *conn;
697         unsigned long flags;
698         LIST_HEAD(list);
699
700         /* get all the messages we're dropping under the rs lock */
701         spin_lock_irqsave(&rs->rs_lock, flags);
702
703         list_for_each_entry_safe(rm, tmp, &rs->rs_send_queue, m_sock_item) {
704                 if (dest && (dest->sin_addr.s_addr != rm->m_daddr ||
705                              dest->sin_port != rm->m_inc.i_hdr.h_dport))
706                         continue;
707
708                 list_move(&rm->m_sock_item, &list);
709                 rds_send_sndbuf_remove(rs, rm);
710                 clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
711         }
712
713         /* order flag updates with the rs lock */
714         smp_mb__after_clear_bit();
715
716         spin_unlock_irqrestore(&rs->rs_lock, flags);
717
718         if (list_empty(&list))
719                 return;
720
721         /* Remove the messages from the conn */
722         list_for_each_entry(rm, &list, m_sock_item) {
723
724                 conn = rm->m_inc.i_conn;
725
726                 spin_lock_irqsave(&conn->c_lock, flags);
727                 /*
728                  * Maybe someone else beat us to removing rm from the conn.
729                  * If we race with their flag update we'll get the lock and
730                  * then really see that the flag has been cleared.
731                  */
732                 if (!test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) {
733                         spin_unlock_irqrestore(&conn->c_lock, flags);
734                         continue;
735                 }
736                 list_del_init(&rm->m_conn_item);
737                 spin_unlock_irqrestore(&conn->c_lock, flags);
738
739                 /*
740                  * Couldn't grab m_rs_lock in top loop (lock ordering),
741                  * but we can now.
742                  */
743                 spin_lock_irqsave(&rm->m_rs_lock, flags);
744
745                 spin_lock(&rs->rs_lock);
746                 __rds_send_complete(rs, rm, RDS_RDMA_CANCELED);
747                 spin_unlock(&rs->rs_lock);
748
749                 rm->m_rs = NULL;
750                 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
751
752                 rds_message_put(rm);
753         }
754
755         rds_wake_sk_sleep(rs);
756
757         while (!list_empty(&list)) {
758                 rm = list_entry(list.next, struct rds_message, m_sock_item);
759                 list_del_init(&rm->m_sock_item);
760
761                 rds_message_wait(rm);
762                 rds_message_put(rm);
763         }
764 }
765
766 /*
767  * we only want this to fire once so we use the callers 'queued'.  It's
768  * possible that another thread can race with us and remove the
769  * message from the flow with RDS_CANCEL_SENT_TO.
770  */
771 static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn,
772                              struct rds_message *rm, __be16 sport,
773                              __be16 dport, int *queued)
774 {
775         unsigned long flags;
776         u32 len;
777
778         if (*queued)
779                 goto out;
780
781         len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
782
783         /* this is the only place which holds both the socket's rs_lock
784          * and the connection's c_lock */
785         spin_lock_irqsave(&rs->rs_lock, flags);
786
787         /*
788          * If there is a little space in sndbuf, we don't queue anything,
789          * and userspace gets -EAGAIN. But poll() indicates there's send
790          * room. This can lead to bad behavior (spinning) if snd_bytes isn't
791          * freed up by incoming acks. So we check the *old* value of
792          * rs_snd_bytes here to allow the last msg to exceed the buffer,
793          * and poll() now knows no more data can be sent.
794          */
795         if (rs->rs_snd_bytes < rds_sk_sndbuf(rs)) {
796                 rs->rs_snd_bytes += len;
797
798                 /* let recv side know we are close to send space exhaustion.
799                  * This is probably not the optimal way to do it, as this
800                  * means we set the flag on *all* messages as soon as our
801                  * throughput hits a certain threshold.
802                  */
803                 if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2)
804                         __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
805
806                 list_add_tail(&rm->m_sock_item, &rs->rs_send_queue);
807                 set_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
808                 rds_message_addref(rm);
809                 rm->m_rs = rs;
810
811                 /* The code ordering is a little weird, but we're
812                    trying to minimize the time we hold c_lock */
813                 rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport, 0);
814                 rm->m_inc.i_conn = conn;
815                 rds_message_addref(rm);
816
817                 spin_lock(&conn->c_lock);
818                 rm->m_inc.i_hdr.h_sequence = cpu_to_be64(conn->c_next_tx_seq++);
819                 list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
820                 set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
821                 spin_unlock(&conn->c_lock);
822
823                 rdsdebug("queued msg %p len %d, rs %p bytes %d seq %llu\n",
824                          rm, len, rs, rs->rs_snd_bytes,
825                          (unsigned long long)be64_to_cpu(rm->m_inc.i_hdr.h_sequence));
826
827                 *queued = 1;
828         }
829
830         spin_unlock_irqrestore(&rs->rs_lock, flags);
831 out:
832         return *queued;
833 }
834
835 /*
836  * rds_message is getting to be quite complicated, and we'd like to allocate
837  * it all in one go. This figures out how big it needs to be up front.
838  */
839 static int rds_rm_size(struct msghdr *msg, int data_len)
840 {
841         struct cmsghdr *cmsg;
842         int size = 0;
843         int cmsg_groups = 0;
844         int retval;
845
846         for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
847                 if (!CMSG_OK(msg, cmsg))
848                         return -EINVAL;
849
850                 if (cmsg->cmsg_level != SOL_RDS)
851                         continue;
852
853                 switch (cmsg->cmsg_type) {
854                 case RDS_CMSG_RDMA_ARGS:
855                         cmsg_groups |= 1;
856                         retval = rds_rdma_extra_size(CMSG_DATA(cmsg));
857                         if (retval < 0)
858                                 return retval;
859                         size += retval;
860
861                         break;
862
863                 case RDS_CMSG_RDMA_DEST:
864                 case RDS_CMSG_RDMA_MAP:
865                         cmsg_groups |= 2;
866                         /* these are valid but do no add any size */
867                         break;
868
869                 case RDS_CMSG_ATOMIC_CSWP:
870                 case RDS_CMSG_ATOMIC_FADD:
871                         cmsg_groups |= 1;
872                         size += sizeof(struct scatterlist);
873                         break;
874
875                 default:
876                         return -EINVAL;
877                 }
878
879         }
880
881         size += ceil(data_len, PAGE_SIZE) * sizeof(struct scatterlist);
882
883         /* Ensure (DEST, MAP) are never used with (ARGS, ATOMIC) */
884         if (cmsg_groups == 3)
885                 return -EINVAL;
886
887         return size;
888 }
889
890 static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
891                          struct msghdr *msg, int *allocated_mr)
892 {
893         struct cmsghdr *cmsg;
894         int ret = 0;
895
896         for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
897                 if (!CMSG_OK(msg, cmsg))
898                         return -EINVAL;
899
900                 if (cmsg->cmsg_level != SOL_RDS)
901                         continue;
902
903                 /* As a side effect, RDMA_DEST and RDMA_MAP will set
904                  * rm->rdma.m_rdma_cookie and rm->rdma.m_rdma_mr.
905                  */
906                 switch (cmsg->cmsg_type) {
907                 case RDS_CMSG_RDMA_ARGS:
908                         ret = rds_cmsg_rdma_args(rs, rm, cmsg);
909                         break;
910
911                 case RDS_CMSG_RDMA_DEST:
912                         ret = rds_cmsg_rdma_dest(rs, rm, cmsg);
913                         break;
914
915                 case RDS_CMSG_RDMA_MAP:
916                         ret = rds_cmsg_rdma_map(rs, rm, cmsg);
917                         if (!ret)
918                                 *allocated_mr = 1;
919                         break;
920                 case RDS_CMSG_ATOMIC_CSWP:
921                 case RDS_CMSG_ATOMIC_FADD:
922                         ret = rds_cmsg_atomic(rs, rm, cmsg);
923                         break;
924
925                 default:
926                         return -EINVAL;
927                 }
928
929                 if (ret)
930                         break;
931         }
932
933         return ret;
934 }
935
936 int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
937                 size_t payload_len)
938 {
939         struct sock *sk = sock->sk;
940         struct rds_sock *rs = rds_sk_to_rs(sk);
941         struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name;
942         __be32 daddr;
943         __be16 dport;
944         struct rds_message *rm = NULL;
945         struct rds_connection *conn;
946         int ret = 0;
947         int queued = 0, allocated_mr = 0;
948         int nonblock = msg->msg_flags & MSG_DONTWAIT;
949         long timeo = sock_sndtimeo(sk, nonblock);
950
951         /* Mirror Linux UDP mirror of BSD error message compatibility */
952         /* XXX: Perhaps MSG_MORE someday */
953         if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) {
954                 printk(KERN_INFO "msg_flags 0x%08X\n", msg->msg_flags);
955                 ret = -EOPNOTSUPP;
956                 goto out;
957         }
958
959         if (msg->msg_namelen) {
960                 /* XXX fail non-unicast destination IPs? */
961                 if (msg->msg_namelen < sizeof(*usin) || usin->sin_family != AF_INET) {
962                         ret = -EINVAL;
963                         goto out;
964                 }
965                 daddr = usin->sin_addr.s_addr;
966                 dport = usin->sin_port;
967         } else {
968                 /* We only care about consistency with ->connect() */
969                 lock_sock(sk);
970                 daddr = rs->rs_conn_addr;
971                 dport = rs->rs_conn_port;
972                 release_sock(sk);
973         }
974
975         /* racing with another thread binding seems ok here */
976         if (daddr == 0 || rs->rs_bound_addr == 0) {
977                 ret = -ENOTCONN; /* XXX not a great errno */
978                 goto out;
979         }
980
981         /* size of rm including all sgs */
982         ret = rds_rm_size(msg, payload_len);
983         if (ret < 0)
984                 goto out;
985
986         rm = rds_message_alloc(ret, GFP_KERNEL);
987         if (!rm) {
988                 ret = -ENOMEM;
989                 goto out;
990         }
991
992         /* Attach data to the rm */
993         if (payload_len) {
994                 rm->data.op_sg = rds_message_alloc_sgs(rm, ceil(payload_len, PAGE_SIZE));
995                 ret = rds_message_copy_from_user(rm, msg->msg_iov, payload_len);
996                 if (ret)
997                         goto out;
998         }
999         rm->data.op_active = 1;
1000
1001         rm->m_daddr = daddr;
1002
1003         /* rds_conn_create has a spinlock that runs with IRQ off.
1004          * Caching the conn in the socket helps a lot. */
1005         if (rs->rs_conn && rs->rs_conn->c_faddr == daddr)
1006                 conn = rs->rs_conn;
1007         else {
1008                 conn = rds_conn_create_outgoing(rs->rs_bound_addr, daddr,
1009                                         rs->rs_transport,
1010                                         sock->sk->sk_allocation);
1011                 if (IS_ERR(conn)) {
1012                         ret = PTR_ERR(conn);
1013                         goto out;
1014                 }
1015                 rs->rs_conn = conn;
1016         }
1017
1018         /* Parse any control messages the user may have included. */
1019         ret = rds_cmsg_send(rs, rm, msg, &allocated_mr);
1020         if (ret)
1021                 goto out;
1022
1023         if (rm->rdma.op_active && !conn->c_trans->xmit_rdma) {
1024                 if (printk_ratelimit())
1025                         printk(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",
1026                                &rm->rdma, conn->c_trans->xmit_rdma);
1027                 ret = -EOPNOTSUPP;
1028                 goto out;
1029         }
1030
1031         if (rm->atomic.op_active && !conn->c_trans->xmit_atomic) {
1032                 if (printk_ratelimit())
1033                         printk(KERN_NOTICE "atomic_op %p conn xmit_atomic %p\n",
1034                                &rm->atomic, conn->c_trans->xmit_atomic);
1035                 ret = -EOPNOTSUPP;
1036                 goto out;
1037         }
1038
1039         /* If the connection is down, trigger a connect. We may
1040          * have scheduled a delayed reconnect however - in this case
1041          * we should not interfere.
1042          */
1043         if (rds_conn_state(conn) == RDS_CONN_DOWN &&
1044             !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
1045                 queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
1046
1047         ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);
1048         if (ret) {
1049                 rs->rs_seen_congestion = 1;
1050                 goto out;
1051         }
1052
1053         while (!rds_send_queue_rm(rs, conn, rm, rs->rs_bound_port,
1054                                   dport, &queued)) {
1055                 rds_stats_inc(s_send_queue_full);
1056                 /* XXX make sure this is reasonable */
1057                 if (payload_len > rds_sk_sndbuf(rs)) {
1058                         ret = -EMSGSIZE;
1059                         goto out;
1060                 }
1061                 if (nonblock) {
1062                         ret = -EAGAIN;
1063                         goto out;
1064                 }
1065
1066                 timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
1067                                         rds_send_queue_rm(rs, conn, rm,
1068                                                           rs->rs_bound_port,
1069                                                           dport,
1070                                                           &queued),
1071                                         timeo);
1072                 rdsdebug("sendmsg woke queued %d timeo %ld\n", queued, timeo);
1073                 if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
1074                         continue;
1075
1076                 ret = timeo;
1077                 if (ret == 0)
1078                         ret = -ETIMEDOUT;
1079                 goto out;
1080         }
1081
1082         /*
1083          * By now we've committed to the send.  We reuse rds_send_worker()
1084          * to retry sends in the rds thread if the transport asks us to.
1085          */
1086         rds_stats_inc(s_send_queued);
1087
1088         if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
1089                 rds_send_xmit(conn);
1090
1091         rds_message_put(rm);
1092         return payload_len;
1093
1094 out:
1095         /* If the user included a RDMA_MAP cmsg, we allocated a MR on the fly.
1096          * If the sendmsg goes through, we keep the MR. If it fails with EAGAIN
1097          * or in any other way, we need to destroy the MR again */
1098         if (allocated_mr)
1099                 rds_rdma_unuse(rs, rds_rdma_cookie_key(rm->m_rdma_cookie), 1);
1100
1101         if (rm)
1102                 rds_message_put(rm);
1103         return ret;
1104 }
1105
1106 /*
1107  * Reply to a ping packet.
1108  */
1109 int
1110 rds_send_pong(struct rds_connection *conn, __be16 dport)
1111 {
1112         struct rds_message *rm;
1113         unsigned long flags;
1114         int ret = 0;
1115
1116         rm = rds_message_alloc(0, GFP_ATOMIC);
1117         if (!rm) {
1118                 ret = -ENOMEM;
1119                 goto out;
1120         }
1121
1122         rm->m_daddr = conn->c_faddr;
1123         rm->data.op_active = 1;
1124
1125         /* If the connection is down, trigger a connect. We may
1126          * have scheduled a delayed reconnect however - in this case
1127          * we should not interfere.
1128          */
1129         if (rds_conn_state(conn) == RDS_CONN_DOWN &&
1130             !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
1131                 queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
1132
1133         ret = rds_cong_wait(conn->c_fcong, dport, 1, NULL);
1134         if (ret)
1135                 goto out;
1136
1137         spin_lock_irqsave(&conn->c_lock, flags);
1138         list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
1139         set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
1140         rds_message_addref(rm);
1141         rm->m_inc.i_conn = conn;
1142
1143         rds_message_populate_header(&rm->m_inc.i_hdr, 0, dport,
1144                                     conn->c_next_tx_seq);
1145         conn->c_next_tx_seq++;
1146         spin_unlock_irqrestore(&conn->c_lock, flags);
1147
1148         rds_stats_inc(s_send_queued);
1149         rds_stats_inc(s_send_pong);
1150
1151         if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
1152                 rds_send_xmit(conn);
1153
1154         rds_message_put(rm);
1155         return 0;
1156
1157 out:
1158         if (rm)
1159                 rds_message_put(rm);
1160         return ret;
1161 }