RDS: Stop supporting old cong map sending method
[linux-3.10.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         if (conn->c_xmit_rm) {
64                 /* Tell the user the RDMA op is no longer mapped by the
65                  * transport. This isn't entirely true (it's flushed out
66                  * independently) but as the connection is down, there's
67                  * no ongoing RDMA to/from that memory */
68                 rds_message_unmapped(conn->c_xmit_rm);
69                 rds_message_put(conn->c_xmit_rm);
70                 conn->c_xmit_rm = NULL;
71         }
72         conn->c_xmit_sg = 0;
73         conn->c_xmit_hdr_off = 0;
74         conn->c_xmit_data_off = 0;
75         conn->c_xmit_atomic_sent = 0;
76         conn->c_xmit_rdma_sent = 0;
77         conn->c_xmit_data_sent = 0;
78
79         conn->c_map_queued = 0;
80
81         conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
82         conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
83
84         /* Mark messages as retransmissions, and move them to the send q */
85         spin_lock_irqsave(&conn->c_lock, flags);
86         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
87                 set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
88                 set_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags);
89         }
90         list_splice_init(&conn->c_retrans, &conn->c_send_queue);
91         spin_unlock_irqrestore(&conn->c_lock, flags);
92 }
93
94 /*
95  * We're making the concious trade-off here to only send one message
96  * down the connection at a time.
97  *   Pro:
98  *      - tx queueing is a simple fifo list
99  *      - reassembly is optional and easily done by transports per conn
100  *      - no per flow rx lookup at all, straight to the socket
101  *      - less per-frag memory and wire overhead
102  *   Con:
103  *      - queued acks can be delayed behind large messages
104  *   Depends:
105  *      - small message latency is higher behind queued large messages
106  *      - large message latency isn't starved by intervening small sends
107  */
108 int rds_send_xmit(struct rds_connection *conn)
109 {
110         struct rds_message *rm;
111         unsigned long flags;
112         unsigned int tmp;
113         unsigned int send_quota = send_batch_count;
114         struct scatterlist *sg;
115         int ret = 0;
116         int was_empty = 0;
117         LIST_HEAD(to_be_dropped);
118
119         /*
120          * sendmsg calls here after having queued its message on the send
121          * queue.  We only have one task feeding the connection at a time.  If
122          * another thread is already feeding the queue then we back off.  This
123          * avoids blocking the caller and trading per-connection data between
124          * caches per message.
125          *
126          * The sem holder will issue a retry if they notice that someone queued
127          * a message after they stopped walking the send queue but before they
128          * dropped the sem.
129          */
130         if (!mutex_trylock(&conn->c_send_lock)) {
131                 rds_stats_inc(s_send_sem_contention);
132                 ret = -ENOMEM;
133                 goto out;
134         }
135
136         if (conn->c_trans->xmit_prepare)
137                 conn->c_trans->xmit_prepare(conn);
138
139         /*
140          * spin trying to push headers and data down the connection until
141          * the connection doesn't make forward progress.
142          */
143         while (--send_quota) {
144
145                 rm = conn->c_xmit_rm;
146
147                 /*
148                  * If between sending messages, we can send a pending congestion
149                  * map update.
150                  */
151                 if (!rm && test_and_clear_bit(0, &conn->c_map_queued)) {
152                         rm = rds_cong_update_alloc(conn);
153                         if (IS_ERR(rm)) {
154                                 ret = PTR_ERR(rm);
155                                 break;
156                         }
157                         rm->data.op_active = 1;
158
159                         conn->c_xmit_rm = rm;
160                 }
161
162                 /*
163                  * If not already working on one, grab the next message.
164                  *
165                  * c_xmit_rm holds a ref while we're sending this message down
166                  * the connction.  We can use this ref while holding the
167                  * send_sem.. rds_send_reset() is serialized with it.
168                  */
169                 if (!rm) {
170                         unsigned int len;
171
172                         spin_lock_irqsave(&conn->c_lock, flags);
173
174                         if (!list_empty(&conn->c_send_queue)) {
175                                 rm = list_entry(conn->c_send_queue.next,
176                                                 struct rds_message,
177                                                 m_conn_item);
178                                 rds_message_addref(rm);
179
180                                 /*
181                                  * Move the message from the send queue to the retransmit
182                                  * list right away.
183                                  */
184                                 list_move_tail(&rm->m_conn_item, &conn->c_retrans);
185                         }
186
187                         spin_unlock_irqrestore(&conn->c_lock, flags);
188
189                         if (!rm) {
190                                 was_empty = 1;
191                                 break;
192                         }
193
194                         /* Unfortunately, the way Infiniband deals with
195                          * RDMA to a bad MR key is by moving the entire
196                          * queue pair to error state. We cold possibly
197                          * recover from that, but right now we drop the
198                          * connection.
199                          * Therefore, we never retransmit messages with RDMA ops.
200                          */
201                         if (rm->rdma.op_active &&
202                             test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) {
203                                 spin_lock_irqsave(&conn->c_lock, flags);
204                                 if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags))
205                                         list_move(&rm->m_conn_item, &to_be_dropped);
206                                 spin_unlock_irqrestore(&conn->c_lock, flags);
207                                 rds_message_put(rm);
208                                 continue;
209                         }
210
211                         /* Require an ACK every once in a while */
212                         len = ntohl(rm->m_inc.i_hdr.h_len);
213                         if (conn->c_unacked_packets == 0 ||
214                             conn->c_unacked_bytes < len) {
215                                 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
216
217                                 conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
218                                 conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
219                                 rds_stats_inc(s_send_ack_required);
220                         } else {
221                                 conn->c_unacked_bytes -= len;
222                                 conn->c_unacked_packets--;
223                         }
224
225                         conn->c_xmit_rm = rm;
226                 }
227
228                 /* The transport either sends the whole rdma or none of it */
229                 if (rm->rdma.op_active && !conn->c_xmit_rdma_sent) {
230                         rm->m_final_op = &rm->rdma;
231                         ret = conn->c_trans->xmit_rdma(conn, &rm->rdma);
232                         if (ret)
233                                 break;
234                         conn->c_xmit_rdma_sent = 1;
235
236                         /* The transport owns the mapped memory for now.
237                          * You can't unmap it while it's on the send queue */
238                         set_bit(RDS_MSG_MAPPED, &rm->m_flags);
239                 }
240
241                 if (rm->atomic.op_active && !conn->c_xmit_atomic_sent) {
242                         rm->m_final_op = &rm->atomic;
243                         ret = conn->c_trans->xmit_atomic(conn, &rm->atomic);
244                         if (ret)
245                                 break;
246                         conn->c_xmit_atomic_sent = 1;
247
248                         /* The transport owns the mapped memory for now.
249                          * You can't unmap it while it's on the send queue */
250                         set_bit(RDS_MSG_MAPPED, &rm->m_flags);
251                 }
252
253                 /*
254                  * A number of cases require an RDS header to be sent
255                  * even if there is no data.
256                  * We permit 0-byte sends; rds-ping depends on this.
257                  * However, if there are exclusively attached silent ops,
258                  * we skip the hdr/data send, to enable silent operation.
259                  */
260                 if (rm->data.op_nents == 0) {
261                         int ops_present;
262                         int all_ops_are_silent = 1;
263
264                         ops_present = (rm->atomic.op_active || rm->rdma.op_active);
265                         if (rm->atomic.op_active && !rm->atomic.op_silent)
266                                 all_ops_are_silent = 0;
267                         if (rm->rdma.op_active && !rm->rdma.op_silent)
268                                 all_ops_are_silent = 0;
269
270                         if (ops_present && all_ops_are_silent
271                             && !rm->m_rdma_cookie)
272                                 rm->data.op_active = 0;
273                 }
274
275                 if (rm->data.op_active && !conn->c_xmit_data_sent) {
276                         rm->m_final_op = &rm->data;
277                         ret = conn->c_trans->xmit(conn, rm,
278                                                   conn->c_xmit_hdr_off,
279                                                   conn->c_xmit_sg,
280                                                   conn->c_xmit_data_off);
281                         if (ret <= 0)
282                                 break;
283
284                         if (conn->c_xmit_hdr_off < sizeof(struct rds_header)) {
285                                 tmp = min_t(int, ret,
286                                             sizeof(struct rds_header) -
287                                             conn->c_xmit_hdr_off);
288                                 conn->c_xmit_hdr_off += tmp;
289                                 ret -= tmp;
290                         }
291
292                         sg = &rm->data.op_sg[conn->c_xmit_sg];
293                         while (ret) {
294                                 tmp = min_t(int, ret, sg->length -
295                                                       conn->c_xmit_data_off);
296                                 conn->c_xmit_data_off += tmp;
297                                 ret -= tmp;
298                                 if (conn->c_xmit_data_off == sg->length) {
299                                         conn->c_xmit_data_off = 0;
300                                         sg++;
301                                         conn->c_xmit_sg++;
302                                         BUG_ON(ret != 0 &&
303                                                conn->c_xmit_sg == rm->data.op_nents);
304                                 }
305                         }
306
307                         if (conn->c_xmit_hdr_off == sizeof(struct rds_header) &&
308                             (conn->c_xmit_sg == rm->data.op_nents))
309                                 conn->c_xmit_data_sent = 1;
310                 }
311
312                 /*
313                  * A rm will only take multiple times through this loop
314                  * if there is a data op. Thus, if the data is sent (or there was
315                  * none), then we're done with the rm.
316                  */
317                 if (!rm->data.op_active || conn->c_xmit_data_sent) {
318                         conn->c_xmit_rm = NULL;
319                         conn->c_xmit_sg = 0;
320                         conn->c_xmit_hdr_off = 0;
321                         conn->c_xmit_data_off = 0;
322                         conn->c_xmit_rdma_sent = 0;
323                         conn->c_xmit_atomic_sent = 0;
324                         conn->c_xmit_data_sent = 0;
325
326                         rds_message_put(rm);
327                 }
328         }
329
330         /* Nuke any messages we decided not to retransmit. */
331         if (!list_empty(&to_be_dropped))
332                 rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED);
333
334         if (conn->c_trans->xmit_complete)
335                 conn->c_trans->xmit_complete(conn);
336
337         /*
338          * We might be racing with another sender who queued a message but
339          * backed off on noticing that we held the c_send_lock.  If we check
340          * for queued messages after dropping the sem then either we'll
341          * see the queued message or the queuer will get the sem.  If we
342          * notice the queued message then we trigger an immediate retry.
343          *
344          * We need to be careful only to do this when we stopped processing
345          * the send queue because it was empty.  It's the only way we
346          * stop processing the loop when the transport hasn't taken
347          * responsibility for forward progress.
348          */
349         mutex_unlock(&conn->c_send_lock);
350
351         if (send_quota == 0 && !was_empty) {
352                 /* We exhausted the send quota, but there's work left to
353                  * do. Return and (re-)schedule the send worker.
354                  */
355                 ret = -EAGAIN;
356         }
357
358         if (ret == 0 && was_empty) {
359                 /* A simple bit test would be way faster than taking the
360                  * spin lock */
361                 spin_lock_irqsave(&conn->c_lock, flags);
362                 if (!list_empty(&conn->c_send_queue)) {
363                         rds_stats_inc(s_send_sem_queue_raced);
364                         ret = -EAGAIN;
365                 }
366                 spin_unlock_irqrestore(&conn->c_lock, flags);
367         }
368 out:
369         return ret;
370 }
371
372 static void rds_send_sndbuf_remove(struct rds_sock *rs, struct rds_message *rm)
373 {
374         u32 len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
375
376         assert_spin_locked(&rs->rs_lock);
377
378         BUG_ON(rs->rs_snd_bytes < len);
379         rs->rs_snd_bytes -= len;
380
381         if (rs->rs_snd_bytes == 0)
382                 rds_stats_inc(s_send_queue_empty);
383 }
384
385 static inline int rds_send_is_acked(struct rds_message *rm, u64 ack,
386                                     is_acked_func is_acked)
387 {
388         if (is_acked)
389                 return is_acked(rm, ack);
390         return be64_to_cpu(rm->m_inc.i_hdr.h_sequence) <= ack;
391 }
392
393 /*
394  * Returns true if there are no messages on the send and retransmit queues
395  * which have a sequence number greater than or equal to the given sequence
396  * number.
397  */
398 int rds_send_acked_before(struct rds_connection *conn, u64 seq)
399 {
400         struct rds_message *rm, *tmp;
401         int ret = 1;
402
403         spin_lock(&conn->c_lock);
404
405         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
406                 if (be64_to_cpu(rm->m_inc.i_hdr.h_sequence) < seq)
407                         ret = 0;
408                 break;
409         }
410
411         list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
412                 if (be64_to_cpu(rm->m_inc.i_hdr.h_sequence) < seq)
413                         ret = 0;
414                 break;
415         }
416
417         spin_unlock(&conn->c_lock);
418
419         return ret;
420 }
421
422 /*
423  * This is pretty similar to what happens below in the ACK
424  * handling code - except that we call here as soon as we get
425  * the IB send completion on the RDMA op and the accompanying
426  * message.
427  */
428 void rds_rdma_send_complete(struct rds_message *rm, int status)
429 {
430         struct rds_sock *rs = NULL;
431         struct rm_rdma_op *ro;
432         struct rds_notifier *notifier;
433         unsigned long flags;
434
435         spin_lock_irqsave(&rm->m_rs_lock, flags);
436
437         ro = &rm->rdma;
438         if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) &&
439             ro->op_active && ro->op_notify && ro->op_notifier) {
440                 notifier = ro->op_notifier;
441                 rs = rm->m_rs;
442                 sock_hold(rds_rs_to_sk(rs));
443
444                 notifier->n_status = status;
445                 spin_lock(&rs->rs_lock);
446                 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
447                 spin_unlock(&rs->rs_lock);
448
449                 ro->op_notifier = NULL;
450         }
451
452         spin_unlock_irqrestore(&rm->m_rs_lock, flags);
453
454         if (rs) {
455                 rds_wake_sk_sleep(rs);
456                 sock_put(rds_rs_to_sk(rs));
457         }
458 }
459 EXPORT_SYMBOL_GPL(rds_rdma_send_complete);
460
461 /*
462  * Just like above, except looks at atomic op
463  */
464 void rds_atomic_send_complete(struct rds_message *rm, int status)
465 {
466         struct rds_sock *rs = NULL;
467         struct rm_atomic_op *ao;
468         struct rds_notifier *notifier;
469
470         spin_lock(&rm->m_rs_lock);
471
472         ao = &rm->atomic;
473         if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags)
474             && ao->op_active && ao->op_notify && ao->op_notifier) {
475                 notifier = ao->op_notifier;
476                 rs = rm->m_rs;
477                 sock_hold(rds_rs_to_sk(rs));
478
479                 notifier->n_status = status;
480                 spin_lock(&rs->rs_lock);
481                 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
482                 spin_unlock(&rs->rs_lock);
483
484                 ao->op_notifier = NULL;
485         }
486
487         spin_unlock(&rm->m_rs_lock);
488
489         if (rs) {
490                 rds_wake_sk_sleep(rs);
491                 sock_put(rds_rs_to_sk(rs));
492         }
493 }
494 EXPORT_SYMBOL_GPL(rds_atomic_send_complete);
495
496 /*
497  * This is the same as rds_rdma_send_complete except we
498  * don't do any locking - we have all the ingredients (message,
499  * socket, socket lock) and can just move the notifier.
500  */
501 static inline void
502 __rds_send_complete(struct rds_sock *rs, struct rds_message *rm, int status)
503 {
504         struct rm_rdma_op *ro;
505         struct rm_atomic_op *ao;
506
507         ro = &rm->rdma;
508         if (ro->op_active && ro->op_notify && ro->op_notifier) {
509                 ro->op_notifier->n_status = status;
510                 list_add_tail(&ro->op_notifier->n_list, &rs->rs_notify_queue);
511                 ro->op_notifier = NULL;
512         }
513
514         ao = &rm->atomic;
515         if (ao->op_active && ao->op_notify && ao->op_notifier) {
516                 ao->op_notifier->n_status = status;
517                 list_add_tail(&ao->op_notifier->n_list, &rs->rs_notify_queue);
518                 ao->op_notifier = NULL;
519         }
520
521         /* No need to wake the app - caller does this */
522 }
523
524 /*
525  * This is called from the IB send completion when we detect
526  * a RDMA operation that failed with remote access error.
527  * So speed is not an issue here.
528  */
529 struct rds_message *rds_send_get_message(struct rds_connection *conn,
530                                          struct rm_rdma_op *op)
531 {
532         struct rds_message *rm, *tmp, *found = NULL;
533         unsigned long flags;
534
535         spin_lock_irqsave(&conn->c_lock, flags);
536
537         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
538                 if (&rm->rdma == op) {
539                         atomic_inc(&rm->m_refcount);
540                         found = rm;
541                         goto out;
542                 }
543         }
544
545         list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
546                 if (&rm->rdma == op) {
547                         atomic_inc(&rm->m_refcount);
548                         found = rm;
549                         break;
550                 }
551         }
552
553 out:
554         spin_unlock_irqrestore(&conn->c_lock, flags);
555
556         return found;
557 }
558 EXPORT_SYMBOL_GPL(rds_send_get_message);
559
560 /*
561  * This removes messages from the socket's list if they're on it.  The list
562  * argument must be private to the caller, we must be able to modify it
563  * without locks.  The messages must have a reference held for their
564  * position on the list.  This function will drop that reference after
565  * removing the messages from the 'messages' list regardless of if it found
566  * the messages on the socket list or not.
567  */
568 void rds_send_remove_from_sock(struct list_head *messages, int status)
569 {
570         unsigned long flags;
571         struct rds_sock *rs = NULL;
572         struct rds_message *rm;
573
574         while (!list_empty(messages)) {
575                 int was_on_sock = 0;
576
577                 rm = list_entry(messages->next, struct rds_message,
578                                 m_conn_item);
579                 list_del_init(&rm->m_conn_item);
580
581                 /*
582                  * If we see this flag cleared then we're *sure* that someone
583                  * else beat us to removing it from the sock.  If we race
584                  * with their flag update we'll get the lock and then really
585                  * see that the flag has been cleared.
586                  *
587                  * The message spinlock makes sure nobody clears rm->m_rs
588                  * while we're messing with it. It does not prevent the
589                  * message from being removed from the socket, though.
590                  */
591                 spin_lock_irqsave(&rm->m_rs_lock, flags);
592                 if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags))
593                         goto unlock_and_drop;
594
595                 if (rs != rm->m_rs) {
596                         if (rs) {
597                                 rds_wake_sk_sleep(rs);
598                                 sock_put(rds_rs_to_sk(rs));
599                         }
600                         rs = rm->m_rs;
601                         sock_hold(rds_rs_to_sk(rs));
602                 }
603                 spin_lock(&rs->rs_lock);
604
605                 if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) {
606                         struct rm_rdma_op *ro = &rm->rdma;
607                         struct rds_notifier *notifier;
608
609                         list_del_init(&rm->m_sock_item);
610                         rds_send_sndbuf_remove(rs, rm);
611
612                         if (ro->op_active && ro->op_notifier &&
613                                (ro->op_notify || (ro->op_recverr && status))) {
614                                 notifier = ro->op_notifier;
615                                 list_add_tail(&notifier->n_list,
616                                                 &rs->rs_notify_queue);
617                                 if (!notifier->n_status)
618                                         notifier->n_status = status;
619                                 rm->rdma.op_notifier = NULL;
620                         }
621                         was_on_sock = 1;
622                         rm->m_rs = NULL;
623                 }
624                 spin_unlock(&rs->rs_lock);
625
626 unlock_and_drop:
627                 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
628                 rds_message_put(rm);
629                 if (was_on_sock)
630                         rds_message_put(rm);
631         }
632
633         if (rs) {
634                 rds_wake_sk_sleep(rs);
635                 sock_put(rds_rs_to_sk(rs));
636         }
637 }
638
639 /*
640  * Transports call here when they've determined that the receiver queued
641  * messages up to, and including, the given sequence number.  Messages are
642  * moved to the retrans queue when rds_send_xmit picks them off the send
643  * queue. This means that in the TCP case, the message may not have been
644  * assigned the m_ack_seq yet - but that's fine as long as tcp_is_acked
645  * checks the RDS_MSG_HAS_ACK_SEQ bit.
646  *
647  * XXX It's not clear to me how this is safely serialized with socket
648  * destruction.  Maybe it should bail if it sees SOCK_DEAD.
649  */
650 void rds_send_drop_acked(struct rds_connection *conn, u64 ack,
651                          is_acked_func is_acked)
652 {
653         struct rds_message *rm, *tmp;
654         unsigned long flags;
655         LIST_HEAD(list);
656
657         spin_lock_irqsave(&conn->c_lock, flags);
658
659         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
660                 if (!rds_send_is_acked(rm, ack, is_acked))
661                         break;
662
663                 list_move(&rm->m_conn_item, &list);
664                 clear_bit(RDS_MSG_ON_CONN, &rm->m_flags);
665         }
666
667         /* order flag updates with spin locks */
668         if (!list_empty(&list))
669                 smp_mb__after_clear_bit();
670
671         spin_unlock_irqrestore(&conn->c_lock, flags);
672
673         /* now remove the messages from the sock list as needed */
674         rds_send_remove_from_sock(&list, RDS_RDMA_SUCCESS);
675 }
676 EXPORT_SYMBOL_GPL(rds_send_drop_acked);
677
678 void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest)
679 {
680         struct rds_message *rm, *tmp;
681         struct rds_connection *conn;
682         unsigned long flags;
683         LIST_HEAD(list);
684
685         /* get all the messages we're dropping under the rs lock */
686         spin_lock_irqsave(&rs->rs_lock, flags);
687
688         list_for_each_entry_safe(rm, tmp, &rs->rs_send_queue, m_sock_item) {
689                 if (dest && (dest->sin_addr.s_addr != rm->m_daddr ||
690                              dest->sin_port != rm->m_inc.i_hdr.h_dport))
691                         continue;
692
693                 list_move(&rm->m_sock_item, &list);
694                 rds_send_sndbuf_remove(rs, rm);
695                 clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
696         }
697
698         /* order flag updates with the rs lock */
699         smp_mb__after_clear_bit();
700
701         spin_unlock_irqrestore(&rs->rs_lock, flags);
702
703         if (list_empty(&list))
704                 return;
705
706         /* Remove the messages from the conn */
707         list_for_each_entry(rm, &list, m_sock_item) {
708
709                 conn = rm->m_inc.i_conn;
710
711                 spin_lock_irqsave(&conn->c_lock, flags);
712                 /*
713                  * Maybe someone else beat us to removing rm from the conn.
714                  * If we race with their flag update we'll get the lock and
715                  * then really see that the flag has been cleared.
716                  */
717                 if (!test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) {
718                         spin_unlock_irqrestore(&conn->c_lock, flags);
719                         continue;
720                 }
721                 list_del_init(&rm->m_conn_item);
722                 spin_unlock_irqrestore(&conn->c_lock, flags);
723
724                 /*
725                  * Couldn't grab m_rs_lock in top loop (lock ordering),
726                  * but we can now.
727                  */
728                 spin_lock_irqsave(&rm->m_rs_lock, flags);
729
730                 spin_lock(&rs->rs_lock);
731                 __rds_send_complete(rs, rm, RDS_RDMA_CANCELED);
732                 spin_unlock(&rs->rs_lock);
733
734                 rm->m_rs = NULL;
735                 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
736
737                 rds_message_put(rm);
738         }
739
740         rds_wake_sk_sleep(rs);
741
742         while (!list_empty(&list)) {
743                 rm = list_entry(list.next, struct rds_message, m_sock_item);
744                 list_del_init(&rm->m_sock_item);
745
746                 rds_message_wait(rm);
747                 rds_message_put(rm);
748         }
749 }
750
751 /*
752  * we only want this to fire once so we use the callers 'queued'.  It's
753  * possible that another thread can race with us and remove the
754  * message from the flow with RDS_CANCEL_SENT_TO.
755  */
756 static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn,
757                              struct rds_message *rm, __be16 sport,
758                              __be16 dport, int *queued)
759 {
760         unsigned long flags;
761         u32 len;
762
763         if (*queued)
764                 goto out;
765
766         len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
767
768         /* this is the only place which holds both the socket's rs_lock
769          * and the connection's c_lock */
770         spin_lock_irqsave(&rs->rs_lock, flags);
771
772         /*
773          * If there is a little space in sndbuf, we don't queue anything,
774          * and userspace gets -EAGAIN. But poll() indicates there's send
775          * room. This can lead to bad behavior (spinning) if snd_bytes isn't
776          * freed up by incoming acks. So we check the *old* value of
777          * rs_snd_bytes here to allow the last msg to exceed the buffer,
778          * and poll() now knows no more data can be sent.
779          */
780         if (rs->rs_snd_bytes < rds_sk_sndbuf(rs)) {
781                 rs->rs_snd_bytes += len;
782
783                 /* let recv side know we are close to send space exhaustion.
784                  * This is probably not the optimal way to do it, as this
785                  * means we set the flag on *all* messages as soon as our
786                  * throughput hits a certain threshold.
787                  */
788                 if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2)
789                         __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
790
791                 list_add_tail(&rm->m_sock_item, &rs->rs_send_queue);
792                 set_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
793                 rds_message_addref(rm);
794                 rm->m_rs = rs;
795
796                 /* The code ordering is a little weird, but we're
797                    trying to minimize the time we hold c_lock */
798                 rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport, 0);
799                 rm->m_inc.i_conn = conn;
800                 rds_message_addref(rm);
801
802                 spin_lock(&conn->c_lock);
803                 rm->m_inc.i_hdr.h_sequence = cpu_to_be64(conn->c_next_tx_seq++);
804                 list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
805                 set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
806                 spin_unlock(&conn->c_lock);
807
808                 rdsdebug("queued msg %p len %d, rs %p bytes %d seq %llu\n",
809                          rm, len, rs, rs->rs_snd_bytes,
810                          (unsigned long long)be64_to_cpu(rm->m_inc.i_hdr.h_sequence));
811
812                 *queued = 1;
813         }
814
815         spin_unlock_irqrestore(&rs->rs_lock, flags);
816 out:
817         return *queued;
818 }
819
820 /*
821  * rds_message is getting to be quite complicated, and we'd like to allocate
822  * it all in one go. This figures out how big it needs to be up front.
823  */
824 static int rds_rm_size(struct msghdr *msg, int data_len)
825 {
826         struct cmsghdr *cmsg;
827         int size = 0;
828         int cmsg_groups = 0;
829         int retval;
830
831         for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
832                 if (!CMSG_OK(msg, cmsg))
833                         return -EINVAL;
834
835                 if (cmsg->cmsg_level != SOL_RDS)
836                         continue;
837
838                 switch (cmsg->cmsg_type) {
839                 case RDS_CMSG_RDMA_ARGS:
840                         cmsg_groups |= 1;
841                         retval = rds_rdma_extra_size(CMSG_DATA(cmsg));
842                         if (retval < 0)
843                                 return retval;
844                         size += retval;
845
846                         break;
847
848                 case RDS_CMSG_RDMA_DEST:
849                 case RDS_CMSG_RDMA_MAP:
850                         cmsg_groups |= 2;
851                         /* these are valid but do no add any size */
852                         break;
853
854                 case RDS_CMSG_ATOMIC_CSWP:
855                 case RDS_CMSG_ATOMIC_FADD:
856                         cmsg_groups |= 1;
857                         size += sizeof(struct scatterlist);
858                         break;
859
860                 default:
861                         return -EINVAL;
862                 }
863
864         }
865
866         size += ceil(data_len, PAGE_SIZE) * sizeof(struct scatterlist);
867
868         /* Ensure (DEST, MAP) are never used with (ARGS, ATOMIC) */
869         if (cmsg_groups == 3)
870                 return -EINVAL;
871
872         return size;
873 }
874
875 static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
876                          struct msghdr *msg, int *allocated_mr)
877 {
878         struct cmsghdr *cmsg;
879         int ret = 0;
880
881         for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
882                 if (!CMSG_OK(msg, cmsg))
883                         return -EINVAL;
884
885                 if (cmsg->cmsg_level != SOL_RDS)
886                         continue;
887
888                 /* As a side effect, RDMA_DEST and RDMA_MAP will set
889                  * rm->rdma.m_rdma_cookie and rm->rdma.m_rdma_mr.
890                  */
891                 switch (cmsg->cmsg_type) {
892                 case RDS_CMSG_RDMA_ARGS:
893                         ret = rds_cmsg_rdma_args(rs, rm, cmsg);
894                         break;
895
896                 case RDS_CMSG_RDMA_DEST:
897                         ret = rds_cmsg_rdma_dest(rs, rm, cmsg);
898                         break;
899
900                 case RDS_CMSG_RDMA_MAP:
901                         ret = rds_cmsg_rdma_map(rs, rm, cmsg);
902                         if (!ret)
903                                 *allocated_mr = 1;
904                         break;
905                 case RDS_CMSG_ATOMIC_CSWP:
906                 case RDS_CMSG_ATOMIC_FADD:
907                         ret = rds_cmsg_atomic(rs, rm, cmsg);
908                         break;
909
910                 default:
911                         return -EINVAL;
912                 }
913
914                 if (ret)
915                         break;
916         }
917
918         return ret;
919 }
920
921 int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
922                 size_t payload_len)
923 {
924         struct sock *sk = sock->sk;
925         struct rds_sock *rs = rds_sk_to_rs(sk);
926         struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name;
927         __be32 daddr;
928         __be16 dport;
929         struct rds_message *rm = NULL;
930         struct rds_connection *conn;
931         int ret = 0;
932         int queued = 0, allocated_mr = 0;
933         int nonblock = msg->msg_flags & MSG_DONTWAIT;
934         long timeo = sock_sndtimeo(sk, nonblock);
935
936         /* Mirror Linux UDP mirror of BSD error message compatibility */
937         /* XXX: Perhaps MSG_MORE someday */
938         if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) {
939                 printk(KERN_INFO "msg_flags 0x%08X\n", msg->msg_flags);
940                 ret = -EOPNOTSUPP;
941                 goto out;
942         }
943
944         if (msg->msg_namelen) {
945                 /* XXX fail non-unicast destination IPs? */
946                 if (msg->msg_namelen < sizeof(*usin) || usin->sin_family != AF_INET) {
947                         ret = -EINVAL;
948                         goto out;
949                 }
950                 daddr = usin->sin_addr.s_addr;
951                 dport = usin->sin_port;
952         } else {
953                 /* We only care about consistency with ->connect() */
954                 lock_sock(sk);
955                 daddr = rs->rs_conn_addr;
956                 dport = rs->rs_conn_port;
957                 release_sock(sk);
958         }
959
960         /* racing with another thread binding seems ok here */
961         if (daddr == 0 || rs->rs_bound_addr == 0) {
962                 ret = -ENOTCONN; /* XXX not a great errno */
963                 goto out;
964         }
965
966         /* size of rm including all sgs */
967         ret = rds_rm_size(msg, payload_len);
968         if (ret < 0)
969                 goto out;
970
971         rm = rds_message_alloc(ret, GFP_KERNEL);
972         if (!rm) {
973                 ret = -ENOMEM;
974                 goto out;
975         }
976
977         /* Attach data to the rm */
978         if (payload_len) {
979                 rm->data.op_sg = rds_message_alloc_sgs(rm, ceil(payload_len, PAGE_SIZE));
980                 ret = rds_message_copy_from_user(rm, msg->msg_iov, payload_len);
981                 if (ret)
982                         goto out;
983         }
984         rm->data.op_active = 1;
985
986         rm->m_daddr = daddr;
987
988         /* rds_conn_create has a spinlock that runs with IRQ off.
989          * Caching the conn in the socket helps a lot. */
990         if (rs->rs_conn && rs->rs_conn->c_faddr == daddr)
991                 conn = rs->rs_conn;
992         else {
993                 conn = rds_conn_create_outgoing(rs->rs_bound_addr, daddr,
994                                         rs->rs_transport,
995                                         sock->sk->sk_allocation);
996                 if (IS_ERR(conn)) {
997                         ret = PTR_ERR(conn);
998                         goto out;
999                 }
1000                 rs->rs_conn = conn;
1001         }
1002
1003         /* Parse any control messages the user may have included. */
1004         ret = rds_cmsg_send(rs, rm, msg, &allocated_mr);
1005         if (ret)
1006                 goto out;
1007
1008         if (rm->rdma.op_active && !conn->c_trans->xmit_rdma) {
1009                 if (printk_ratelimit())
1010                         printk(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",
1011                                &rm->rdma, conn->c_trans->xmit_rdma);
1012                 ret = -EOPNOTSUPP;
1013                 goto out;
1014         }
1015
1016         if (rm->atomic.op_active && !conn->c_trans->xmit_atomic) {
1017                 if (printk_ratelimit())
1018                         printk(KERN_NOTICE "atomic_op %p conn xmit_atomic %p\n",
1019                                &rm->atomic, conn->c_trans->xmit_atomic);
1020                 ret = -EOPNOTSUPP;
1021                 goto out;
1022         }
1023
1024         /* If the connection is down, trigger a connect. We may
1025          * have scheduled a delayed reconnect however - in this case
1026          * we should not interfere.
1027          */
1028         if (rds_conn_state(conn) == RDS_CONN_DOWN &&
1029             !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
1030                 queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
1031
1032         ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);
1033         if (ret) {
1034                 rs->rs_seen_congestion = 1;
1035                 goto out;
1036         }
1037
1038         while (!rds_send_queue_rm(rs, conn, rm, rs->rs_bound_port,
1039                                   dport, &queued)) {
1040                 rds_stats_inc(s_send_queue_full);
1041                 /* XXX make sure this is reasonable */
1042                 if (payload_len > rds_sk_sndbuf(rs)) {
1043                         ret = -EMSGSIZE;
1044                         goto out;
1045                 }
1046                 if (nonblock) {
1047                         ret = -EAGAIN;
1048                         goto out;
1049                 }
1050
1051                 timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
1052                                         rds_send_queue_rm(rs, conn, rm,
1053                                                           rs->rs_bound_port,
1054                                                           dport,
1055                                                           &queued),
1056                                         timeo);
1057                 rdsdebug("sendmsg woke queued %d timeo %ld\n", queued, timeo);
1058                 if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
1059                         continue;
1060
1061                 ret = timeo;
1062                 if (ret == 0)
1063                         ret = -ETIMEDOUT;
1064                 goto out;
1065         }
1066
1067         /*
1068          * By now we've committed to the send.  We reuse rds_send_worker()
1069          * to retry sends in the rds thread if the transport asks us to.
1070          */
1071         rds_stats_inc(s_send_queued);
1072
1073         if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
1074                 rds_send_worker(&conn->c_send_w.work);
1075
1076         rds_message_put(rm);
1077         return payload_len;
1078
1079 out:
1080         /* If the user included a RDMA_MAP cmsg, we allocated a MR on the fly.
1081          * If the sendmsg goes through, we keep the MR. If it fails with EAGAIN
1082          * or in any other way, we need to destroy the MR again */
1083         if (allocated_mr)
1084                 rds_rdma_unuse(rs, rds_rdma_cookie_key(rm->m_rdma_cookie), 1);
1085
1086         if (rm)
1087                 rds_message_put(rm);
1088         return ret;
1089 }
1090
1091 /*
1092  * Reply to a ping packet.
1093  */
1094 int
1095 rds_send_pong(struct rds_connection *conn, __be16 dport)
1096 {
1097         struct rds_message *rm;
1098         unsigned long flags;
1099         int ret = 0;
1100
1101         rm = rds_message_alloc(0, GFP_ATOMIC);
1102         if (!rm) {
1103                 ret = -ENOMEM;
1104                 goto out;
1105         }
1106
1107         rm->m_daddr = conn->c_faddr;
1108
1109         /* If the connection is down, trigger a connect. We may
1110          * have scheduled a delayed reconnect however - in this case
1111          * we should not interfere.
1112          */
1113         if (rds_conn_state(conn) == RDS_CONN_DOWN &&
1114             !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
1115                 queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
1116
1117         ret = rds_cong_wait(conn->c_fcong, dport, 1, NULL);
1118         if (ret)
1119                 goto out;
1120
1121         spin_lock_irqsave(&conn->c_lock, flags);
1122         list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
1123         set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
1124         rds_message_addref(rm);
1125         rm->m_inc.i_conn = conn;
1126
1127         rds_message_populate_header(&rm->m_inc.i_hdr, 0, dport,
1128                                     conn->c_next_tx_seq);
1129         conn->c_next_tx_seq++;
1130         spin_unlock_irqrestore(&conn->c_lock, flags);
1131
1132         rds_stats_inc(s_send_queued);
1133         rds_stats_inc(s_send_pong);
1134
1135         queue_delayed_work(rds_wq, &conn->c_send_w, 0);
1136         rds_message_put(rm);
1137         return 0;
1138
1139 out:
1140         if (rm)
1141                 rds_message_put(rm);
1142         return ret;
1143 }