RDS/IB: Do not wait for send ring to be empty on conn shutdown
[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         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                  * Transports either define a special xmit_cong_map function,
152                  * or we allocate a cong_map message and treat it just like any
153                  * other send.
154                  */
155                 if (!rm && test_and_clear_bit(0, &conn->c_map_queued)) {
156                         if (conn->c_trans->xmit_cong_map) {
157                                 unsigned long map_offset = 0;
158                                 unsigned long map_bytes = sizeof(struct rds_header) +
159                                         RDS_CONG_MAP_BYTES;
160
161                                 while (map_bytes) {
162                                         ret = conn->c_trans->xmit_cong_map(conn, conn->c_lcong,
163                                                                            map_offset);
164                                         if (ret <= 0) {
165                                                 /* too far down the rabbithole! */
166                                                 mutex_unlock(&conn->c_send_lock);
167                                                 rds_conn_error(conn, "Cong map xmit failed\n");
168                                                 goto out;
169                                         }
170
171                                         map_offset += ret;
172                                         map_bytes -= ret;
173                                 }
174                         } else {
175                                 /* send cong update like a normal rm */
176                                 rm = rds_cong_update_alloc(conn);
177                                 if (IS_ERR(rm)) {
178                                         ret = PTR_ERR(rm);
179                                         break;
180                                 }
181                                 rm->data.op_active = 1;
182
183                                 conn->c_xmit_rm = rm;
184                         }
185                 }
186
187                 /*
188                  * If not already working on one, grab the next message.
189                  *
190                  * c_xmit_rm holds a ref while we're sending this message down
191                  * the connction.  We can use this ref while holding the
192                  * send_sem.. rds_send_reset() is serialized with it.
193                  */
194                 if (!rm) {
195                         unsigned int len;
196
197                         spin_lock_irqsave(&conn->c_lock, flags);
198
199                         if (!list_empty(&conn->c_send_queue)) {
200                                 rm = list_entry(conn->c_send_queue.next,
201                                                 struct rds_message,
202                                                 m_conn_item);
203                                 rds_message_addref(rm);
204
205                                 /*
206                                  * Move the message from the send queue to the retransmit
207                                  * list right away.
208                                  */
209                                 list_move_tail(&rm->m_conn_item, &conn->c_retrans);
210                         }
211
212                         spin_unlock_irqrestore(&conn->c_lock, flags);
213
214                         if (!rm) {
215                                 was_empty = 1;
216                                 break;
217                         }
218
219                         /* Unfortunately, the way Infiniband deals with
220                          * RDMA to a bad MR key is by moving the entire
221                          * queue pair to error state. We cold possibly
222                          * recover from that, but right now we drop the
223                          * connection.
224                          * Therefore, we never retransmit messages with RDMA ops.
225                          */
226                         if (rm->rdma.op_active &&
227                             test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) {
228                                 spin_lock_irqsave(&conn->c_lock, flags);
229                                 if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags))
230                                         list_move(&rm->m_conn_item, &to_be_dropped);
231                                 spin_unlock_irqrestore(&conn->c_lock, flags);
232                                 rds_message_put(rm);
233                                 continue;
234                         }
235
236                         /* Require an ACK every once in a while */
237                         len = ntohl(rm->m_inc.i_hdr.h_len);
238                         if (conn->c_unacked_packets == 0 ||
239                             conn->c_unacked_bytes < len) {
240                                 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
241
242                                 conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
243                                 conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
244                                 rds_stats_inc(s_send_ack_required);
245                         } else {
246                                 conn->c_unacked_bytes -= len;
247                                 conn->c_unacked_packets--;
248                         }
249
250                         conn->c_xmit_rm = rm;
251                 }
252
253                 /* The transport either sends the whole rdma or none of it */
254                 if (rm->rdma.op_active && !conn->c_xmit_rdma_sent) {
255                         rm->m_final_op = &rm->rdma;
256                         ret = conn->c_trans->xmit_rdma(conn, &rm->rdma);
257                         if (ret)
258                                 break;
259                         conn->c_xmit_rdma_sent = 1;
260
261                         /* The transport owns the mapped memory for now.
262                          * You can't unmap it while it's on the send queue */
263                         set_bit(RDS_MSG_MAPPED, &rm->m_flags);
264                 }
265
266                 if (rm->atomic.op_active && !conn->c_xmit_atomic_sent) {
267                         rm->m_final_op = &rm->atomic;
268                         ret = conn->c_trans->xmit_atomic(conn, &rm->atomic);
269                         if (ret)
270                                 break;
271                         conn->c_xmit_atomic_sent = 1;
272
273                         /* The transport owns the mapped memory for now.
274                          * You can't unmap it while it's on the send queue */
275                         set_bit(RDS_MSG_MAPPED, &rm->m_flags);
276                 }
277
278                 /*
279                  * A number of cases require an RDS header to be sent
280                  * even if there is no data.
281                  * We permit 0-byte sends; rds-ping depends on this.
282                  * However, if there are exclusively attached silent ops,
283                  * we skip the hdr/data send, to enable silent operation.
284                  */
285                 if (rm->data.op_nents == 0) {
286                         int ops_present;
287                         int all_ops_are_silent = 1;
288
289                         ops_present = (rm->atomic.op_active || rm->rdma.op_active);
290                         if (rm->atomic.op_active && !rm->atomic.op_silent)
291                                 all_ops_are_silent = 0;
292                         if (rm->rdma.op_active && !rm->rdma.op_silent)
293                                 all_ops_are_silent = 0;
294
295                         if (ops_present && all_ops_are_silent
296                             && !rm->m_rdma_cookie)
297                                 rm->data.op_active = 0;
298                 }
299
300                 if (rm->data.op_active && !conn->c_xmit_data_sent) {
301                         rm->m_final_op = &rm->data;
302                         ret = conn->c_trans->xmit(conn, rm,
303                                                   conn->c_xmit_hdr_off,
304                                                   conn->c_xmit_sg,
305                                                   conn->c_xmit_data_off);
306                         if (ret <= 0)
307                                 break;
308
309                         if (conn->c_xmit_hdr_off < sizeof(struct rds_header)) {
310                                 tmp = min_t(int, ret,
311                                             sizeof(struct rds_header) -
312                                             conn->c_xmit_hdr_off);
313                                 conn->c_xmit_hdr_off += tmp;
314                                 ret -= tmp;
315                         }
316
317                         sg = &rm->data.op_sg[conn->c_xmit_sg];
318                         while (ret) {
319                                 tmp = min_t(int, ret, sg->length -
320                                                       conn->c_xmit_data_off);
321                                 conn->c_xmit_data_off += tmp;
322                                 ret -= tmp;
323                                 if (conn->c_xmit_data_off == sg->length) {
324                                         conn->c_xmit_data_off = 0;
325                                         sg++;
326                                         conn->c_xmit_sg++;
327                                         BUG_ON(ret != 0 &&
328                                                conn->c_xmit_sg == rm->data.op_nents);
329                                 }
330                         }
331
332                         if (conn->c_xmit_hdr_off == sizeof(struct rds_header) &&
333                             (conn->c_xmit_sg == rm->data.op_nents))
334                                 conn->c_xmit_data_sent = 1;
335                 }
336
337                 /*
338                  * A rm will only take multiple times through this loop
339                  * if there is a data op. Thus, if the data is sent (or there was
340                  * none), then we're done with the rm.
341                  */
342                 if (!rm->data.op_active || conn->c_xmit_data_sent) {
343                         conn->c_xmit_rm = NULL;
344                         conn->c_xmit_sg = 0;
345                         conn->c_xmit_hdr_off = 0;
346                         conn->c_xmit_data_off = 0;
347                         conn->c_xmit_rdma_sent = 0;
348                         conn->c_xmit_atomic_sent = 0;
349                         conn->c_xmit_data_sent = 0;
350
351                         rds_message_put(rm);
352                 }
353         }
354
355         /* Nuke any messages we decided not to retransmit. */
356         if (!list_empty(&to_be_dropped))
357                 rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED);
358
359         if (conn->c_trans->xmit_complete)
360                 conn->c_trans->xmit_complete(conn);
361
362         /*
363          * We might be racing with another sender who queued a message but
364          * backed off on noticing that we held the c_send_lock.  If we check
365          * for queued messages after dropping the sem then either we'll
366          * see the queued message or the queuer will get the sem.  If we
367          * notice the queued message then we trigger an immediate retry.
368          *
369          * We need to be careful only to do this when we stopped processing
370          * the send queue because it was empty.  It's the only way we
371          * stop processing the loop when the transport hasn't taken
372          * responsibility for forward progress.
373          */
374         mutex_unlock(&conn->c_send_lock);
375
376         if (send_quota == 0 && !was_empty) {
377                 /* We exhausted the send quota, but there's work left to
378                  * do. Return and (re-)schedule the send worker.
379                  */
380                 ret = -EAGAIN;
381         }
382
383         if (ret == 0 && was_empty) {
384                 /* A simple bit test would be way faster than taking the
385                  * spin lock */
386                 spin_lock_irqsave(&conn->c_lock, flags);
387                 if (!list_empty(&conn->c_send_queue)) {
388                         rds_stats_inc(s_send_sem_queue_raced);
389                         ret = -EAGAIN;
390                 }
391                 spin_unlock_irqrestore(&conn->c_lock, flags);
392         }
393 out:
394         return ret;
395 }
396
397 static void rds_send_sndbuf_remove(struct rds_sock *rs, struct rds_message *rm)
398 {
399         u32 len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
400
401         assert_spin_locked(&rs->rs_lock);
402
403         BUG_ON(rs->rs_snd_bytes < len);
404         rs->rs_snd_bytes -= len;
405
406         if (rs->rs_snd_bytes == 0)
407                 rds_stats_inc(s_send_queue_empty);
408 }
409
410 static inline int rds_send_is_acked(struct rds_message *rm, u64 ack,
411                                     is_acked_func is_acked)
412 {
413         if (is_acked)
414                 return is_acked(rm, ack);
415         return be64_to_cpu(rm->m_inc.i_hdr.h_sequence) <= ack;
416 }
417
418 /*
419  * Returns true if there are no messages on the send and retransmit queues
420  * which have a sequence number greater than or equal to the given sequence
421  * number.
422  */
423 int rds_send_acked_before(struct rds_connection *conn, u64 seq)
424 {
425         struct rds_message *rm, *tmp;
426         int ret = 1;
427
428         spin_lock(&conn->c_lock);
429
430         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
431                 if (be64_to_cpu(rm->m_inc.i_hdr.h_sequence) < seq)
432                         ret = 0;
433                 break;
434         }
435
436         list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
437                 if (be64_to_cpu(rm->m_inc.i_hdr.h_sequence) < seq)
438                         ret = 0;
439                 break;
440         }
441
442         spin_unlock(&conn->c_lock);
443
444         return ret;
445 }
446
447 /*
448  * This is pretty similar to what happens below in the ACK
449  * handling code - except that we call here as soon as we get
450  * the IB send completion on the RDMA op and the accompanying
451  * message.
452  */
453 void rds_rdma_send_complete(struct rds_message *rm, int status)
454 {
455         struct rds_sock *rs = NULL;
456         struct rm_rdma_op *ro;
457         struct rds_notifier *notifier;
458         unsigned long flags;
459
460         spin_lock_irqsave(&rm->m_rs_lock, flags);
461
462         ro = &rm->rdma;
463         if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) &&
464             ro->op_active && ro->op_notify && ro->op_notifier) {
465                 notifier = ro->op_notifier;
466                 rs = rm->m_rs;
467                 sock_hold(rds_rs_to_sk(rs));
468
469                 notifier->n_status = status;
470                 spin_lock(&rs->rs_lock);
471                 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
472                 spin_unlock(&rs->rs_lock);
473
474                 ro->op_notifier = NULL;
475         }
476
477         spin_unlock_irqrestore(&rm->m_rs_lock, flags);
478
479         if (rs) {
480                 rds_wake_sk_sleep(rs);
481                 sock_put(rds_rs_to_sk(rs));
482         }
483 }
484 EXPORT_SYMBOL_GPL(rds_rdma_send_complete);
485
486 /*
487  * Just like above, except looks at atomic op
488  */
489 void rds_atomic_send_complete(struct rds_message *rm, int status)
490 {
491         struct rds_sock *rs = NULL;
492         struct rm_atomic_op *ao;
493         struct rds_notifier *notifier;
494
495         spin_lock(&rm->m_rs_lock);
496
497         ao = &rm->atomic;
498         if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags)
499             && ao->op_active && ao->op_notify && ao->op_notifier) {
500                 notifier = ao->op_notifier;
501                 rs = rm->m_rs;
502                 sock_hold(rds_rs_to_sk(rs));
503
504                 notifier->n_status = status;
505                 spin_lock(&rs->rs_lock);
506                 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
507                 spin_unlock(&rs->rs_lock);
508
509                 ao->op_notifier = NULL;
510         }
511
512         spin_unlock(&rm->m_rs_lock);
513
514         if (rs) {
515                 rds_wake_sk_sleep(rs);
516                 sock_put(rds_rs_to_sk(rs));
517         }
518 }
519 EXPORT_SYMBOL_GPL(rds_atomic_send_complete);
520
521 /*
522  * This is the same as rds_rdma_send_complete except we
523  * don't do any locking - we have all the ingredients (message,
524  * socket, socket lock) and can just move the notifier.
525  */
526 static inline void
527 __rds_send_complete(struct rds_sock *rs, struct rds_message *rm, int status)
528 {
529         struct rm_rdma_op *ro;
530         struct rm_atomic_op *ao;
531
532         ro = &rm->rdma;
533         if (ro->op_active && ro->op_notify && ro->op_notifier) {
534                 ro->op_notifier->n_status = status;
535                 list_add_tail(&ro->op_notifier->n_list, &rs->rs_notify_queue);
536                 ro->op_notifier = NULL;
537         }
538
539         ao = &rm->atomic;
540         if (ao->op_active && ao->op_notify && ao->op_notifier) {
541                 ao->op_notifier->n_status = status;
542                 list_add_tail(&ao->op_notifier->n_list, &rs->rs_notify_queue);
543                 ao->op_notifier = NULL;
544         }
545
546         /* No need to wake the app - caller does this */
547 }
548
549 /*
550  * This is called from the IB send completion when we detect
551  * a RDMA operation that failed with remote access error.
552  * So speed is not an issue here.
553  */
554 struct rds_message *rds_send_get_message(struct rds_connection *conn,
555                                          struct rm_rdma_op *op)
556 {
557         struct rds_message *rm, *tmp, *found = NULL;
558         unsigned long flags;
559
560         spin_lock_irqsave(&conn->c_lock, flags);
561
562         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
563                 if (&rm->rdma == op) {
564                         atomic_inc(&rm->m_refcount);
565                         found = rm;
566                         goto out;
567                 }
568         }
569
570         list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
571                 if (&rm->rdma == op) {
572                         atomic_inc(&rm->m_refcount);
573                         found = rm;
574                         break;
575                 }
576         }
577
578 out:
579         spin_unlock_irqrestore(&conn->c_lock, flags);
580
581         return found;
582 }
583 EXPORT_SYMBOL_GPL(rds_send_get_message);
584
585 /*
586  * This removes messages from the socket's list if they're on it.  The list
587  * argument must be private to the caller, we must be able to modify it
588  * without locks.  The messages must have a reference held for their
589  * position on the list.  This function will drop that reference after
590  * removing the messages from the 'messages' list regardless of if it found
591  * the messages on the socket list or not.
592  */
593 void rds_send_remove_from_sock(struct list_head *messages, int status)
594 {
595         unsigned long flags;
596         struct rds_sock *rs = NULL;
597         struct rds_message *rm;
598
599         while (!list_empty(messages)) {
600                 int was_on_sock = 0;
601
602                 rm = list_entry(messages->next, struct rds_message,
603                                 m_conn_item);
604                 list_del_init(&rm->m_conn_item);
605
606                 /*
607                  * If we see this flag cleared then we're *sure* that someone
608                  * else beat us to removing it from the sock.  If we race
609                  * with their flag update we'll get the lock and then really
610                  * see that the flag has been cleared.
611                  *
612                  * The message spinlock makes sure nobody clears rm->m_rs
613                  * while we're messing with it. It does not prevent the
614                  * message from being removed from the socket, though.
615                  */
616                 spin_lock_irqsave(&rm->m_rs_lock, flags);
617                 if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags))
618                         goto unlock_and_drop;
619
620                 if (rs != rm->m_rs) {
621                         if (rs) {
622                                 rds_wake_sk_sleep(rs);
623                                 sock_put(rds_rs_to_sk(rs));
624                         }
625                         rs = rm->m_rs;
626                         sock_hold(rds_rs_to_sk(rs));
627                 }
628                 spin_lock(&rs->rs_lock);
629
630                 if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) {
631                         struct rm_rdma_op *ro = &rm->rdma;
632                         struct rds_notifier *notifier;
633
634                         list_del_init(&rm->m_sock_item);
635                         rds_send_sndbuf_remove(rs, rm);
636
637                         if (ro->op_active && ro->op_notifier &&
638                                (ro->op_notify || (ro->op_recverr && status))) {
639                                 notifier = ro->op_notifier;
640                                 list_add_tail(&notifier->n_list,
641                                                 &rs->rs_notify_queue);
642                                 if (!notifier->n_status)
643                                         notifier->n_status = status;
644                                 rm->rdma.op_notifier = NULL;
645                         }
646                         was_on_sock = 1;
647                         rm->m_rs = NULL;
648                 }
649                 spin_unlock(&rs->rs_lock);
650
651 unlock_and_drop:
652                 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
653                 rds_message_put(rm);
654                 if (was_on_sock)
655                         rds_message_put(rm);
656         }
657
658         if (rs) {
659                 rds_wake_sk_sleep(rs);
660                 sock_put(rds_rs_to_sk(rs));
661         }
662 }
663
664 /*
665  * Transports call here when they've determined that the receiver queued
666  * messages up to, and including, the given sequence number.  Messages are
667  * moved to the retrans queue when rds_send_xmit picks them off the send
668  * queue. This means that in the TCP case, the message may not have been
669  * assigned the m_ack_seq yet - but that's fine as long as tcp_is_acked
670  * checks the RDS_MSG_HAS_ACK_SEQ bit.
671  *
672  * XXX It's not clear to me how this is safely serialized with socket
673  * destruction.  Maybe it should bail if it sees SOCK_DEAD.
674  */
675 void rds_send_drop_acked(struct rds_connection *conn, u64 ack,
676                          is_acked_func is_acked)
677 {
678         struct rds_message *rm, *tmp;
679         unsigned long flags;
680         LIST_HEAD(list);
681
682         spin_lock_irqsave(&conn->c_lock, flags);
683
684         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
685                 if (!rds_send_is_acked(rm, ack, is_acked))
686                         break;
687
688                 list_move(&rm->m_conn_item, &list);
689                 clear_bit(RDS_MSG_ON_CONN, &rm->m_flags);
690         }
691
692         /* order flag updates with spin locks */
693         if (!list_empty(&list))
694                 smp_mb__after_clear_bit();
695
696         spin_unlock_irqrestore(&conn->c_lock, flags);
697
698         /* now remove the messages from the sock list as needed */
699         rds_send_remove_from_sock(&list, RDS_RDMA_SUCCESS);
700 }
701 EXPORT_SYMBOL_GPL(rds_send_drop_acked);
702
703 void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest)
704 {
705         struct rds_message *rm, *tmp;
706         struct rds_connection *conn;
707         unsigned long flags;
708         LIST_HEAD(list);
709
710         /* get all the messages we're dropping under the rs lock */
711         spin_lock_irqsave(&rs->rs_lock, flags);
712
713         list_for_each_entry_safe(rm, tmp, &rs->rs_send_queue, m_sock_item) {
714                 if (dest && (dest->sin_addr.s_addr != rm->m_daddr ||
715                              dest->sin_port != rm->m_inc.i_hdr.h_dport))
716                         continue;
717
718                 list_move(&rm->m_sock_item, &list);
719                 rds_send_sndbuf_remove(rs, rm);
720                 clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
721         }
722
723         /* order flag updates with the rs lock */
724         smp_mb__after_clear_bit();
725
726         spin_unlock_irqrestore(&rs->rs_lock, flags);
727
728         if (list_empty(&list))
729                 return;
730
731         /* Remove the messages from the conn */
732         list_for_each_entry(rm, &list, m_sock_item) {
733
734                 conn = rm->m_inc.i_conn;
735
736                 spin_lock_irqsave(&conn->c_lock, flags);
737                 /*
738                  * Maybe someone else beat us to removing rm from the conn.
739                  * If we race with their flag update we'll get the lock and
740                  * then really see that the flag has been cleared.
741                  */
742                 if (!test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) {
743                         spin_unlock_irqrestore(&conn->c_lock, flags);
744                         continue;
745                 }
746                 list_del_init(&rm->m_conn_item);
747                 spin_unlock_irqrestore(&conn->c_lock, flags);
748
749                 /*
750                  * Couldn't grab m_rs_lock in top loop (lock ordering),
751                  * but we can now.
752                  */
753                 spin_lock_irqsave(&rm->m_rs_lock, flags);
754
755                 spin_lock(&rs->rs_lock);
756                 __rds_send_complete(rs, rm, RDS_RDMA_CANCELED);
757                 spin_unlock(&rs->rs_lock);
758
759                 rm->m_rs = NULL;
760                 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
761
762                 rds_message_put(rm);
763         }
764
765         rds_wake_sk_sleep(rs);
766
767         while (!list_empty(&list)) {
768                 rm = list_entry(list.next, struct rds_message, m_sock_item);
769                 list_del_init(&rm->m_sock_item);
770
771                 rds_message_wait(rm);
772                 rds_message_put(rm);
773         }
774 }
775
776 /*
777  * we only want this to fire once so we use the callers 'queued'.  It's
778  * possible that another thread can race with us and remove the
779  * message from the flow with RDS_CANCEL_SENT_TO.
780  */
781 static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn,
782                              struct rds_message *rm, __be16 sport,
783                              __be16 dport, int *queued)
784 {
785         unsigned long flags;
786         u32 len;
787
788         if (*queued)
789                 goto out;
790
791         len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
792
793         /* this is the only place which holds both the socket's rs_lock
794          * and the connection's c_lock */
795         spin_lock_irqsave(&rs->rs_lock, flags);
796
797         /*
798          * If there is a little space in sndbuf, we don't queue anything,
799          * and userspace gets -EAGAIN. But poll() indicates there's send
800          * room. This can lead to bad behavior (spinning) if snd_bytes isn't
801          * freed up by incoming acks. So we check the *old* value of
802          * rs_snd_bytes here to allow the last msg to exceed the buffer,
803          * and poll() now knows no more data can be sent.
804          */
805         if (rs->rs_snd_bytes < rds_sk_sndbuf(rs)) {
806                 rs->rs_snd_bytes += len;
807
808                 /* let recv side know we are close to send space exhaustion.
809                  * This is probably not the optimal way to do it, as this
810                  * means we set the flag on *all* messages as soon as our
811                  * throughput hits a certain threshold.
812                  */
813                 if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2)
814                         __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
815
816                 list_add_tail(&rm->m_sock_item, &rs->rs_send_queue);
817                 set_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
818                 rds_message_addref(rm);
819                 rm->m_rs = rs;
820
821                 /* The code ordering is a little weird, but we're
822                    trying to minimize the time we hold c_lock */
823                 rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport, 0);
824                 rm->m_inc.i_conn = conn;
825                 rds_message_addref(rm);
826
827                 spin_lock(&conn->c_lock);
828                 rm->m_inc.i_hdr.h_sequence = cpu_to_be64(conn->c_next_tx_seq++);
829                 list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
830                 set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
831                 spin_unlock(&conn->c_lock);
832
833                 rdsdebug("queued msg %p len %d, rs %p bytes %d seq %llu\n",
834                          rm, len, rs, rs->rs_snd_bytes,
835                          (unsigned long long)be64_to_cpu(rm->m_inc.i_hdr.h_sequence));
836
837                 *queued = 1;
838         }
839
840         spin_unlock_irqrestore(&rs->rs_lock, flags);
841 out:
842         return *queued;
843 }
844
845 /*
846  * rds_message is getting to be quite complicated, and we'd like to allocate
847  * it all in one go. This figures out how big it needs to be up front.
848  */
849 static int rds_rm_size(struct msghdr *msg, int data_len)
850 {
851         struct cmsghdr *cmsg;
852         int size = 0;
853         int cmsg_groups = 0;
854         int retval;
855
856         for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
857                 if (!CMSG_OK(msg, cmsg))
858                         return -EINVAL;
859
860                 if (cmsg->cmsg_level != SOL_RDS)
861                         continue;
862
863                 switch (cmsg->cmsg_type) {
864                 case RDS_CMSG_RDMA_ARGS:
865                         cmsg_groups |= 1;
866                         retval = rds_rdma_extra_size(CMSG_DATA(cmsg));
867                         if (retval < 0)
868                                 return retval;
869                         size += retval;
870
871                         break;
872
873                 case RDS_CMSG_RDMA_DEST:
874                 case RDS_CMSG_RDMA_MAP:
875                         cmsg_groups |= 2;
876                         /* these are valid but do no add any size */
877                         break;
878
879                 case RDS_CMSG_ATOMIC_CSWP:
880                 case RDS_CMSG_ATOMIC_FADD:
881                         cmsg_groups |= 1;
882                         size += sizeof(struct scatterlist);
883                         break;
884
885                 default:
886                         return -EINVAL;
887                 }
888
889         }
890
891         size += ceil(data_len, PAGE_SIZE) * sizeof(struct scatterlist);
892
893         /* Ensure (DEST, MAP) are never used with (ARGS, ATOMIC) */
894         if (cmsg_groups == 3)
895                 return -EINVAL;
896
897         return size;
898 }
899
900 static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
901                          struct msghdr *msg, int *allocated_mr)
902 {
903         struct cmsghdr *cmsg;
904         int ret = 0;
905
906         for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
907                 if (!CMSG_OK(msg, cmsg))
908                         return -EINVAL;
909
910                 if (cmsg->cmsg_level != SOL_RDS)
911                         continue;
912
913                 /* As a side effect, RDMA_DEST and RDMA_MAP will set
914                  * rm->rdma.m_rdma_cookie and rm->rdma.m_rdma_mr.
915                  */
916                 switch (cmsg->cmsg_type) {
917                 case RDS_CMSG_RDMA_ARGS:
918                         ret = rds_cmsg_rdma_args(rs, rm, cmsg);
919                         break;
920
921                 case RDS_CMSG_RDMA_DEST:
922                         ret = rds_cmsg_rdma_dest(rs, rm, cmsg);
923                         break;
924
925                 case RDS_CMSG_RDMA_MAP:
926                         ret = rds_cmsg_rdma_map(rs, rm, cmsg);
927                         if (!ret)
928                                 *allocated_mr = 1;
929                         break;
930                 case RDS_CMSG_ATOMIC_CSWP:
931                 case RDS_CMSG_ATOMIC_FADD:
932                         ret = rds_cmsg_atomic(rs, rm, cmsg);
933                         break;
934
935                 default:
936                         return -EINVAL;
937                 }
938
939                 if (ret)
940                         break;
941         }
942
943         return ret;
944 }
945
946 int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
947                 size_t payload_len)
948 {
949         struct sock *sk = sock->sk;
950         struct rds_sock *rs = rds_sk_to_rs(sk);
951         struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name;
952         __be32 daddr;
953         __be16 dport;
954         struct rds_message *rm = NULL;
955         struct rds_connection *conn;
956         int ret = 0;
957         int queued = 0, allocated_mr = 0;
958         int nonblock = msg->msg_flags & MSG_DONTWAIT;
959         long timeo = sock_sndtimeo(sk, nonblock);
960
961         /* Mirror Linux UDP mirror of BSD error message compatibility */
962         /* XXX: Perhaps MSG_MORE someday */
963         if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) {
964                 printk(KERN_INFO "msg_flags 0x%08X\n", msg->msg_flags);
965                 ret = -EOPNOTSUPP;
966                 goto out;
967         }
968
969         if (msg->msg_namelen) {
970                 /* XXX fail non-unicast destination IPs? */
971                 if (msg->msg_namelen < sizeof(*usin) || usin->sin_family != AF_INET) {
972                         ret = -EINVAL;
973                         goto out;
974                 }
975                 daddr = usin->sin_addr.s_addr;
976                 dport = usin->sin_port;
977         } else {
978                 /* We only care about consistency with ->connect() */
979                 lock_sock(sk);
980                 daddr = rs->rs_conn_addr;
981                 dport = rs->rs_conn_port;
982                 release_sock(sk);
983         }
984
985         /* racing with another thread binding seems ok here */
986         if (daddr == 0 || rs->rs_bound_addr == 0) {
987                 ret = -ENOTCONN; /* XXX not a great errno */
988                 goto out;
989         }
990
991         /* size of rm including all sgs */
992         ret = rds_rm_size(msg, payload_len);
993         if (ret < 0)
994                 goto out;
995
996         rm = rds_message_alloc(ret, GFP_KERNEL);
997         if (!rm) {
998                 ret = -ENOMEM;
999                 goto out;
1000         }
1001
1002         /* Attach data to the rm */
1003         if (payload_len) {
1004                 rm->data.op_sg = rds_message_alloc_sgs(rm, ceil(payload_len, PAGE_SIZE));
1005                 ret = rds_message_copy_from_user(rm, msg->msg_iov, payload_len);
1006                 if (ret)
1007                         goto out;
1008         }
1009         rm->data.op_active = 1;
1010
1011         rm->m_daddr = daddr;
1012
1013         /* rds_conn_create has a spinlock that runs with IRQ off.
1014          * Caching the conn in the socket helps a lot. */
1015         if (rs->rs_conn && rs->rs_conn->c_faddr == daddr)
1016                 conn = rs->rs_conn;
1017         else {
1018                 conn = rds_conn_create_outgoing(rs->rs_bound_addr, daddr,
1019                                         rs->rs_transport,
1020                                         sock->sk->sk_allocation);
1021                 if (IS_ERR(conn)) {
1022                         ret = PTR_ERR(conn);
1023                         goto out;
1024                 }
1025                 rs->rs_conn = conn;
1026         }
1027
1028         /* Parse any control messages the user may have included. */
1029         ret = rds_cmsg_send(rs, rm, msg, &allocated_mr);
1030         if (ret)
1031                 goto out;
1032
1033         if (rm->rdma.op_active && !conn->c_trans->xmit_rdma) {
1034                 if (printk_ratelimit())
1035                         printk(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",
1036                                &rm->rdma, conn->c_trans->xmit_rdma);
1037                 ret = -EOPNOTSUPP;
1038                 goto out;
1039         }
1040
1041         if (rm->atomic.op_active && !conn->c_trans->xmit_atomic) {
1042                 if (printk_ratelimit())
1043                         printk(KERN_NOTICE "atomic_op %p conn xmit_atomic %p\n",
1044                                &rm->atomic, conn->c_trans->xmit_atomic);
1045                 ret = -EOPNOTSUPP;
1046                 goto out;
1047         }
1048
1049         /* If the connection is down, trigger a connect. We may
1050          * have scheduled a delayed reconnect however - in this case
1051          * we should not interfere.
1052          */
1053         if (rds_conn_state(conn) == RDS_CONN_DOWN &&
1054             !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
1055                 queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
1056
1057         ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);
1058         if (ret) {
1059                 rs->rs_seen_congestion = 1;
1060                 goto out;
1061         }
1062
1063         while (!rds_send_queue_rm(rs, conn, rm, rs->rs_bound_port,
1064                                   dport, &queued)) {
1065                 rds_stats_inc(s_send_queue_full);
1066                 /* XXX make sure this is reasonable */
1067                 if (payload_len > rds_sk_sndbuf(rs)) {
1068                         ret = -EMSGSIZE;
1069                         goto out;
1070                 }
1071                 if (nonblock) {
1072                         ret = -EAGAIN;
1073                         goto out;
1074                 }
1075
1076                 timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
1077                                         rds_send_queue_rm(rs, conn, rm,
1078                                                           rs->rs_bound_port,
1079                                                           dport,
1080                                                           &queued),
1081                                         timeo);
1082                 rdsdebug("sendmsg woke queued %d timeo %ld\n", queued, timeo);
1083                 if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
1084                         continue;
1085
1086                 ret = timeo;
1087                 if (ret == 0)
1088                         ret = -ETIMEDOUT;
1089                 goto out;
1090         }
1091
1092         /*
1093          * By now we've committed to the send.  We reuse rds_send_worker()
1094          * to retry sends in the rds thread if the transport asks us to.
1095          */
1096         rds_stats_inc(s_send_queued);
1097
1098         if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
1099                 rds_send_worker(&conn->c_send_w.work);
1100
1101         rds_message_put(rm);
1102         return payload_len;
1103
1104 out:
1105         /* If the user included a RDMA_MAP cmsg, we allocated a MR on the fly.
1106          * If the sendmsg goes through, we keep the MR. If it fails with EAGAIN
1107          * or in any other way, we need to destroy the MR again */
1108         if (allocated_mr)
1109                 rds_rdma_unuse(rs, rds_rdma_cookie_key(rm->m_rdma_cookie), 1);
1110
1111         if (rm)
1112                 rds_message_put(rm);
1113         return ret;
1114 }
1115
1116 /*
1117  * Reply to a ping packet.
1118  */
1119 int
1120 rds_send_pong(struct rds_connection *conn, __be16 dport)
1121 {
1122         struct rds_message *rm;
1123         unsigned long flags;
1124         int ret = 0;
1125
1126         rm = rds_message_alloc(0, GFP_ATOMIC);
1127         if (!rm) {
1128                 ret = -ENOMEM;
1129                 goto out;
1130         }
1131
1132         rm->m_daddr = conn->c_faddr;
1133
1134         /* If the connection is down, trigger a connect. We may
1135          * have scheduled a delayed reconnect however - in this case
1136          * we should not interfere.
1137          */
1138         if (rds_conn_state(conn) == RDS_CONN_DOWN &&
1139             !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
1140                 queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
1141
1142         ret = rds_cong_wait(conn->c_fcong, dport, 1, NULL);
1143         if (ret)
1144                 goto out;
1145
1146         spin_lock_irqsave(&conn->c_lock, flags);
1147         list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
1148         set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
1149         rds_message_addref(rm);
1150         rm->m_inc.i_conn = conn;
1151
1152         rds_message_populate_header(&rm->m_inc.i_hdr, 0, dport,
1153                                     conn->c_next_tx_seq);
1154         conn->c_next_tx_seq++;
1155         spin_unlock_irqrestore(&conn->c_lock, flags);
1156
1157         rds_stats_inc(s_send_queued);
1158         rds_stats_inc(s_send_pong);
1159
1160         queue_delayed_work(rds_wq, &conn->c_send_w, 0);
1161         rds_message_put(rm);
1162         return 0;
1163
1164 out:
1165         if (rm)
1166                 rds_message_put(rm);
1167         return ret;
1168 }