rds: make local functions/variables static
[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 static void rds_send_remove_from_sock(struct list_head *messages, int status);
56
57 /*
58  * Reset the send state.  Callers must ensure that this doesn't race with
59  * rds_send_xmit().
60  */
61 void rds_send_reset(struct rds_connection *conn)
62 {
63         struct rds_message *rm, *tmp;
64         unsigned long flags;
65
66         if (conn->c_xmit_rm) {
67                 rm = conn->c_xmit_rm;
68                 conn->c_xmit_rm = NULL;
69                 /* Tell the user the RDMA op is no longer mapped by the
70                  * transport. This isn't entirely true (it's flushed out
71                  * independently) but as the connection is down, there's
72                  * no ongoing RDMA to/from that memory */
73                 rds_message_unmapped(rm);
74                 rds_message_put(rm);
75         }
76
77         conn->c_xmit_sg = 0;
78         conn->c_xmit_hdr_off = 0;
79         conn->c_xmit_data_off = 0;
80         conn->c_xmit_atomic_sent = 0;
81         conn->c_xmit_rdma_sent = 0;
82         conn->c_xmit_data_sent = 0;
83
84         conn->c_map_queued = 0;
85
86         conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
87         conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
88
89         /* Mark messages as retransmissions, and move them to the send q */
90         spin_lock_irqsave(&conn->c_lock, flags);
91         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
92                 set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
93                 set_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags);
94         }
95         list_splice_init(&conn->c_retrans, &conn->c_send_queue);
96         spin_unlock_irqrestore(&conn->c_lock, flags);
97 }
98
99 static int acquire_in_xmit(struct rds_connection *conn)
100 {
101         return test_and_set_bit(RDS_IN_XMIT, &conn->c_flags) == 0;
102 }
103
104 static void release_in_xmit(struct rds_connection *conn)
105 {
106         clear_bit(RDS_IN_XMIT, &conn->c_flags);
107         smp_mb__after_clear_bit();
108         /*
109          * We don't use wait_on_bit()/wake_up_bit() because our waking is in a
110          * hot path and finding waiters is very rare.  We don't want to walk
111          * the system-wide hashed waitqueue buckets in the fast path only to
112          * almost never find waiters.
113          */
114         if (waitqueue_active(&conn->c_waitq))
115                 wake_up_all(&conn->c_waitq);
116 }
117
118 /*
119  * We're making the concious trade-off here to only send one message
120  * down the connection at a time.
121  *   Pro:
122  *      - tx queueing is a simple fifo list
123  *      - reassembly is optional and easily done by transports per conn
124  *      - no per flow rx lookup at all, straight to the socket
125  *      - less per-frag memory and wire overhead
126  *   Con:
127  *      - queued acks can be delayed behind large messages
128  *   Depends:
129  *      - small message latency is higher behind queued large messages
130  *      - large message latency isn't starved by intervening small sends
131  */
132 int rds_send_xmit(struct rds_connection *conn)
133 {
134         struct rds_message *rm;
135         unsigned long flags;
136         unsigned int tmp;
137         struct scatterlist *sg;
138         int ret = 0;
139         LIST_HEAD(to_be_dropped);
140
141 restart:
142
143         /*
144          * sendmsg calls here after having queued its message on the send
145          * queue.  We only have one task feeding the connection at a time.  If
146          * another thread is already feeding the queue then we back off.  This
147          * avoids blocking the caller and trading per-connection data between
148          * caches per message.
149          */
150         if (!acquire_in_xmit(conn)) {
151                 rds_stats_inc(s_send_lock_contention);
152                 ret = -ENOMEM;
153                 goto out;
154         }
155
156         /*
157          * rds_conn_shutdown() sets the conn state and then tests RDS_IN_XMIT,
158          * we do the opposite to avoid races.
159          */
160         if (!rds_conn_up(conn)) {
161                 release_in_xmit(conn);
162                 ret = 0;
163                 goto out;
164         }
165
166         if (conn->c_trans->xmit_prepare)
167                 conn->c_trans->xmit_prepare(conn);
168
169         /*
170          * spin trying to push headers and data down the connection until
171          * the connection doesn't make forward progress.
172          */
173         while (1) {
174
175                 rm = conn->c_xmit_rm;
176
177                 /*
178                  * If between sending messages, we can send a pending congestion
179                  * map update.
180                  */
181                 if (!rm && test_and_clear_bit(0, &conn->c_map_queued)) {
182                         rm = rds_cong_update_alloc(conn);
183                         if (IS_ERR(rm)) {
184                                 ret = PTR_ERR(rm);
185                                 break;
186                         }
187                         rm->data.op_active = 1;
188
189                         conn->c_xmit_rm = rm;
190                 }
191
192                 /*
193                  * If not already working on one, grab the next message.
194                  *
195                  * c_xmit_rm holds a ref while we're sending this message down
196                  * the connction.  We can use this ref while holding the
197                  * send_sem.. rds_send_reset() is serialized with it.
198                  */
199                 if (!rm) {
200                         unsigned int len;
201
202                         spin_lock_irqsave(&conn->c_lock, flags);
203
204                         if (!list_empty(&conn->c_send_queue)) {
205                                 rm = list_entry(conn->c_send_queue.next,
206                                                 struct rds_message,
207                                                 m_conn_item);
208                                 rds_message_addref(rm);
209
210                                 /*
211                                  * Move the message from the send queue to the retransmit
212                                  * list right away.
213                                  */
214                                 list_move_tail(&rm->m_conn_item, &conn->c_retrans);
215                         }
216
217                         spin_unlock_irqrestore(&conn->c_lock, flags);
218
219                         if (!rm)
220                                 break;
221
222                         /* Unfortunately, the way Infiniband deals with
223                          * RDMA to a bad MR key is by moving the entire
224                          * queue pair to error state. We cold possibly
225                          * recover from that, but right now we drop the
226                          * connection.
227                          * Therefore, we never retransmit messages with RDMA ops.
228                          */
229                         if (rm->rdma.op_active &&
230                             test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) {
231                                 spin_lock_irqsave(&conn->c_lock, flags);
232                                 if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags))
233                                         list_move(&rm->m_conn_item, &to_be_dropped);
234                                 spin_unlock_irqrestore(&conn->c_lock, flags);
235                                 continue;
236                         }
237
238                         /* Require an ACK every once in a while */
239                         len = ntohl(rm->m_inc.i_hdr.h_len);
240                         if (conn->c_unacked_packets == 0 ||
241                             conn->c_unacked_bytes < len) {
242                                 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
243
244                                 conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
245                                 conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
246                                 rds_stats_inc(s_send_ack_required);
247                         } else {
248                                 conn->c_unacked_bytes -= len;
249                                 conn->c_unacked_packets--;
250                         }
251
252                         conn->c_xmit_rm = rm;
253                 }
254
255                 /* The transport either sends the whole rdma or none of it */
256                 if (rm->rdma.op_active && !conn->c_xmit_rdma_sent) {
257                         rm->m_final_op = &rm->rdma;
258                         ret = conn->c_trans->xmit_rdma(conn, &rm->rdma);
259                         if (ret)
260                                 break;
261                         conn->c_xmit_rdma_sent = 1;
262
263                         /* The transport owns the mapped memory for now.
264                          * You can't unmap it while it's on the send queue */
265                         set_bit(RDS_MSG_MAPPED, &rm->m_flags);
266                 }
267
268                 if (rm->atomic.op_active && !conn->c_xmit_atomic_sent) {
269                         rm->m_final_op = &rm->atomic;
270                         ret = conn->c_trans->xmit_atomic(conn, &rm->atomic);
271                         if (ret)
272                                 break;
273                         conn->c_xmit_atomic_sent = 1;
274
275                         /* The transport owns the mapped memory for now.
276                          * You can't unmap it while it's on the send queue */
277                         set_bit(RDS_MSG_MAPPED, &rm->m_flags);
278                 }
279
280                 /*
281                  * A number of cases require an RDS header to be sent
282                  * even if there is no data.
283                  * We permit 0-byte sends; rds-ping depends on this.
284                  * However, if there are exclusively attached silent ops,
285                  * we skip the hdr/data send, to enable silent operation.
286                  */
287                 if (rm->data.op_nents == 0) {
288                         int ops_present;
289                         int all_ops_are_silent = 1;
290
291                         ops_present = (rm->atomic.op_active || rm->rdma.op_active);
292                         if (rm->atomic.op_active && !rm->atomic.op_silent)
293                                 all_ops_are_silent = 0;
294                         if (rm->rdma.op_active && !rm->rdma.op_silent)
295                                 all_ops_are_silent = 0;
296
297                         if (ops_present && all_ops_are_silent
298                             && !rm->m_rdma_cookie)
299                                 rm->data.op_active = 0;
300                 }
301
302                 if (rm->data.op_active && !conn->c_xmit_data_sent) {
303                         rm->m_final_op = &rm->data;
304                         ret = conn->c_trans->xmit(conn, rm,
305                                                   conn->c_xmit_hdr_off,
306                                                   conn->c_xmit_sg,
307                                                   conn->c_xmit_data_off);
308                         if (ret <= 0)
309                                 break;
310
311                         if (conn->c_xmit_hdr_off < sizeof(struct rds_header)) {
312                                 tmp = min_t(int, ret,
313                                             sizeof(struct rds_header) -
314                                             conn->c_xmit_hdr_off);
315                                 conn->c_xmit_hdr_off += tmp;
316                                 ret -= tmp;
317                         }
318
319                         sg = &rm->data.op_sg[conn->c_xmit_sg];
320                         while (ret) {
321                                 tmp = min_t(int, ret, sg->length -
322                                                       conn->c_xmit_data_off);
323                                 conn->c_xmit_data_off += tmp;
324                                 ret -= tmp;
325                                 if (conn->c_xmit_data_off == sg->length) {
326                                         conn->c_xmit_data_off = 0;
327                                         sg++;
328                                         conn->c_xmit_sg++;
329                                         BUG_ON(ret != 0 &&
330                                                conn->c_xmit_sg == rm->data.op_nents);
331                                 }
332                         }
333
334                         if (conn->c_xmit_hdr_off == sizeof(struct rds_header) &&
335                             (conn->c_xmit_sg == rm->data.op_nents))
336                                 conn->c_xmit_data_sent = 1;
337                 }
338
339                 /*
340                  * A rm will only take multiple times through this loop
341                  * if there is a data op. Thus, if the data is sent (or there was
342                  * none), then we're done with the rm.
343                  */
344                 if (!rm->data.op_active || conn->c_xmit_data_sent) {
345                         conn->c_xmit_rm = NULL;
346                         conn->c_xmit_sg = 0;
347                         conn->c_xmit_hdr_off = 0;
348                         conn->c_xmit_data_off = 0;
349                         conn->c_xmit_rdma_sent = 0;
350                         conn->c_xmit_atomic_sent = 0;
351                         conn->c_xmit_data_sent = 0;
352
353                         rds_message_put(rm);
354                 }
355         }
356
357         if (conn->c_trans->xmit_complete)
358                 conn->c_trans->xmit_complete(conn);
359
360         release_in_xmit(conn);
361
362         /* Nuke any messages we decided not to retransmit. */
363         if (!list_empty(&to_be_dropped)) {
364                 /* irqs on here, so we can put(), unlike above */
365                 list_for_each_entry(rm, &to_be_dropped, m_conn_item)
366                         rds_message_put(rm);
367                 rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED);
368         }
369
370         /*
371          * Other senders can queue a message after we last test the send queue
372          * but before we clear RDS_IN_XMIT.  In that case they'd back off and
373          * not try and send their newly queued message.  We need to check the
374          * send queue after having cleared RDS_IN_XMIT so that their message
375          * doesn't get stuck on the send queue.
376          *
377          * If the transport cannot continue (i.e ret != 0), then it must
378          * call us when more room is available, such as from the tx
379          * completion handler.
380          */
381         if (ret == 0) {
382                 smp_mb();
383                 if (!list_empty(&conn->c_send_queue)) {
384                         rds_stats_inc(s_send_lock_queue_raced);
385                         goto restart;
386                 }
387         }
388 out:
389         return ret;
390 }
391
392 static void rds_send_sndbuf_remove(struct rds_sock *rs, struct rds_message *rm)
393 {
394         u32 len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
395
396         assert_spin_locked(&rs->rs_lock);
397
398         BUG_ON(rs->rs_snd_bytes < len);
399         rs->rs_snd_bytes -= len;
400
401         if (rs->rs_snd_bytes == 0)
402                 rds_stats_inc(s_send_queue_empty);
403 }
404
405 static inline int rds_send_is_acked(struct rds_message *rm, u64 ack,
406                                     is_acked_func is_acked)
407 {
408         if (is_acked)
409                 return is_acked(rm, ack);
410         return be64_to_cpu(rm->m_inc.i_hdr.h_sequence) <= ack;
411 }
412
413 /*
414  * This is pretty similar to what happens below in the ACK
415  * handling code - except that we call here as soon as we get
416  * the IB send completion on the RDMA op and the accompanying
417  * message.
418  */
419 void rds_rdma_send_complete(struct rds_message *rm, int status)
420 {
421         struct rds_sock *rs = NULL;
422         struct rm_rdma_op *ro;
423         struct rds_notifier *notifier;
424         unsigned long flags;
425
426         spin_lock_irqsave(&rm->m_rs_lock, flags);
427
428         ro = &rm->rdma;
429         if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) &&
430             ro->op_active && ro->op_notify && ro->op_notifier) {
431                 notifier = ro->op_notifier;
432                 rs = rm->m_rs;
433                 sock_hold(rds_rs_to_sk(rs));
434
435                 notifier->n_status = status;
436                 spin_lock(&rs->rs_lock);
437                 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
438                 spin_unlock(&rs->rs_lock);
439
440                 ro->op_notifier = NULL;
441         }
442
443         spin_unlock_irqrestore(&rm->m_rs_lock, flags);
444
445         if (rs) {
446                 rds_wake_sk_sleep(rs);
447                 sock_put(rds_rs_to_sk(rs));
448         }
449 }
450 EXPORT_SYMBOL_GPL(rds_rdma_send_complete);
451
452 /*
453  * Just like above, except looks at atomic op
454  */
455 void rds_atomic_send_complete(struct rds_message *rm, int status)
456 {
457         struct rds_sock *rs = NULL;
458         struct rm_atomic_op *ao;
459         struct rds_notifier *notifier;
460         unsigned long flags;
461
462         spin_lock_irqsave(&rm->m_rs_lock, flags);
463
464         ao = &rm->atomic;
465         if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags)
466             && ao->op_active && ao->op_notify && ao->op_notifier) {
467                 notifier = ao->op_notifier;
468                 rs = rm->m_rs;
469                 sock_hold(rds_rs_to_sk(rs));
470
471                 notifier->n_status = status;
472                 spin_lock(&rs->rs_lock);
473                 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
474                 spin_unlock(&rs->rs_lock);
475
476                 ao->op_notifier = NULL;
477         }
478
479         spin_unlock_irqrestore(&rm->m_rs_lock, flags);
480
481         if (rs) {
482                 rds_wake_sk_sleep(rs);
483                 sock_put(rds_rs_to_sk(rs));
484         }
485 }
486 EXPORT_SYMBOL_GPL(rds_atomic_send_complete);
487
488 /*
489  * This is the same as rds_rdma_send_complete except we
490  * don't do any locking - we have all the ingredients (message,
491  * socket, socket lock) and can just move the notifier.
492  */
493 static inline void
494 __rds_send_complete(struct rds_sock *rs, struct rds_message *rm, int status)
495 {
496         struct rm_rdma_op *ro;
497         struct rm_atomic_op *ao;
498
499         ro = &rm->rdma;
500         if (ro->op_active && ro->op_notify && ro->op_notifier) {
501                 ro->op_notifier->n_status = status;
502                 list_add_tail(&ro->op_notifier->n_list, &rs->rs_notify_queue);
503                 ro->op_notifier = NULL;
504         }
505
506         ao = &rm->atomic;
507         if (ao->op_active && ao->op_notify && ao->op_notifier) {
508                 ao->op_notifier->n_status = status;
509                 list_add_tail(&ao->op_notifier->n_list, &rs->rs_notify_queue);
510                 ao->op_notifier = NULL;
511         }
512
513         /* No need to wake the app - caller does this */
514 }
515
516 /*
517  * This is called from the IB send completion when we detect
518  * a RDMA operation that failed with remote access error.
519  * So speed is not an issue here.
520  */
521 struct rds_message *rds_send_get_message(struct rds_connection *conn,
522                                          struct rm_rdma_op *op)
523 {
524         struct rds_message *rm, *tmp, *found = NULL;
525         unsigned long flags;
526
527         spin_lock_irqsave(&conn->c_lock, flags);
528
529         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
530                 if (&rm->rdma == op) {
531                         atomic_inc(&rm->m_refcount);
532                         found = rm;
533                         goto out;
534                 }
535         }
536
537         list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
538                 if (&rm->rdma == op) {
539                         atomic_inc(&rm->m_refcount);
540                         found = rm;
541                         break;
542                 }
543         }
544
545 out:
546         spin_unlock_irqrestore(&conn->c_lock, flags);
547
548         return found;
549 }
550 EXPORT_SYMBOL_GPL(rds_send_get_message);
551
552 /*
553  * This removes messages from the socket's list if they're on it.  The list
554  * argument must be private to the caller, we must be able to modify it
555  * without locks.  The messages must have a reference held for their
556  * position on the list.  This function will drop that reference after
557  * removing the messages from the 'messages' list regardless of if it found
558  * the messages on the socket list or not.
559  */
560 static void rds_send_remove_from_sock(struct list_head *messages, int status)
561 {
562         unsigned long flags;
563         struct rds_sock *rs = NULL;
564         struct rds_message *rm;
565
566         while (!list_empty(messages)) {
567                 int was_on_sock = 0;
568
569                 rm = list_entry(messages->next, struct rds_message,
570                                 m_conn_item);
571                 list_del_init(&rm->m_conn_item);
572
573                 /*
574                  * If we see this flag cleared then we're *sure* that someone
575                  * else beat us to removing it from the sock.  If we race
576                  * with their flag update we'll get the lock and then really
577                  * see that the flag has been cleared.
578                  *
579                  * The message spinlock makes sure nobody clears rm->m_rs
580                  * while we're messing with it. It does not prevent the
581                  * message from being removed from the socket, though.
582                  */
583                 spin_lock_irqsave(&rm->m_rs_lock, flags);
584                 if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags))
585                         goto unlock_and_drop;
586
587                 if (rs != rm->m_rs) {
588                         if (rs) {
589                                 rds_wake_sk_sleep(rs);
590                                 sock_put(rds_rs_to_sk(rs));
591                         }
592                         rs = rm->m_rs;
593                         sock_hold(rds_rs_to_sk(rs));
594                 }
595                 spin_lock(&rs->rs_lock);
596
597                 if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) {
598                         struct rm_rdma_op *ro = &rm->rdma;
599                         struct rds_notifier *notifier;
600
601                         list_del_init(&rm->m_sock_item);
602                         rds_send_sndbuf_remove(rs, rm);
603
604                         if (ro->op_active && ro->op_notifier &&
605                                (ro->op_notify || (ro->op_recverr && status))) {
606                                 notifier = ro->op_notifier;
607                                 list_add_tail(&notifier->n_list,
608                                                 &rs->rs_notify_queue);
609                                 if (!notifier->n_status)
610                                         notifier->n_status = status;
611                                 rm->rdma.op_notifier = NULL;
612                         }
613                         was_on_sock = 1;
614                         rm->m_rs = NULL;
615                 }
616                 spin_unlock(&rs->rs_lock);
617
618 unlock_and_drop:
619                 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
620                 rds_message_put(rm);
621                 if (was_on_sock)
622                         rds_message_put(rm);
623         }
624
625         if (rs) {
626                 rds_wake_sk_sleep(rs);
627                 sock_put(rds_rs_to_sk(rs));
628         }
629 }
630
631 /*
632  * Transports call here when they've determined that the receiver queued
633  * messages up to, and including, the given sequence number.  Messages are
634  * moved to the retrans queue when rds_send_xmit picks them off the send
635  * queue. This means that in the TCP case, the message may not have been
636  * assigned the m_ack_seq yet - but that's fine as long as tcp_is_acked
637  * checks the RDS_MSG_HAS_ACK_SEQ bit.
638  *
639  * XXX It's not clear to me how this is safely serialized with socket
640  * destruction.  Maybe it should bail if it sees SOCK_DEAD.
641  */
642 void rds_send_drop_acked(struct rds_connection *conn, u64 ack,
643                          is_acked_func is_acked)
644 {
645         struct rds_message *rm, *tmp;
646         unsigned long flags;
647         LIST_HEAD(list);
648
649         spin_lock_irqsave(&conn->c_lock, flags);
650
651         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
652                 if (!rds_send_is_acked(rm, ack, is_acked))
653                         break;
654
655                 list_move(&rm->m_conn_item, &list);
656                 clear_bit(RDS_MSG_ON_CONN, &rm->m_flags);
657         }
658
659         /* order flag updates with spin locks */
660         if (!list_empty(&list))
661                 smp_mb__after_clear_bit();
662
663         spin_unlock_irqrestore(&conn->c_lock, flags);
664
665         /* now remove the messages from the sock list as needed */
666         rds_send_remove_from_sock(&list, RDS_RDMA_SUCCESS);
667 }
668 EXPORT_SYMBOL_GPL(rds_send_drop_acked);
669
670 void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest)
671 {
672         struct rds_message *rm, *tmp;
673         struct rds_connection *conn;
674         unsigned long flags;
675         LIST_HEAD(list);
676
677         /* get all the messages we're dropping under the rs lock */
678         spin_lock_irqsave(&rs->rs_lock, flags);
679
680         list_for_each_entry_safe(rm, tmp, &rs->rs_send_queue, m_sock_item) {
681                 if (dest && (dest->sin_addr.s_addr != rm->m_daddr ||
682                              dest->sin_port != rm->m_inc.i_hdr.h_dport))
683                         continue;
684
685                 list_move(&rm->m_sock_item, &list);
686                 rds_send_sndbuf_remove(rs, rm);
687                 clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
688         }
689
690         /* order flag updates with the rs lock */
691         smp_mb__after_clear_bit();
692
693         spin_unlock_irqrestore(&rs->rs_lock, flags);
694
695         if (list_empty(&list))
696                 return;
697
698         /* Remove the messages from the conn */
699         list_for_each_entry(rm, &list, m_sock_item) {
700
701                 conn = rm->m_inc.i_conn;
702
703                 spin_lock_irqsave(&conn->c_lock, flags);
704                 /*
705                  * Maybe someone else beat us to removing rm from the conn.
706                  * If we race with their flag update we'll get the lock and
707                  * then really see that the flag has been cleared.
708                  */
709                 if (!test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) {
710                         spin_unlock_irqrestore(&conn->c_lock, flags);
711                         continue;
712                 }
713                 list_del_init(&rm->m_conn_item);
714                 spin_unlock_irqrestore(&conn->c_lock, flags);
715
716                 /*
717                  * Couldn't grab m_rs_lock in top loop (lock ordering),
718                  * but we can now.
719                  */
720                 spin_lock_irqsave(&rm->m_rs_lock, flags);
721
722                 spin_lock(&rs->rs_lock);
723                 __rds_send_complete(rs, rm, RDS_RDMA_CANCELED);
724                 spin_unlock(&rs->rs_lock);
725
726                 rm->m_rs = NULL;
727                 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
728
729                 rds_message_put(rm);
730         }
731
732         rds_wake_sk_sleep(rs);
733
734         while (!list_empty(&list)) {
735                 rm = list_entry(list.next, struct rds_message, m_sock_item);
736                 list_del_init(&rm->m_sock_item);
737
738                 rds_message_wait(rm);
739                 rds_message_put(rm);
740         }
741 }
742
743 /*
744  * we only want this to fire once so we use the callers 'queued'.  It's
745  * possible that another thread can race with us and remove the
746  * message from the flow with RDS_CANCEL_SENT_TO.
747  */
748 static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn,
749                              struct rds_message *rm, __be16 sport,
750                              __be16 dport, int *queued)
751 {
752         unsigned long flags;
753         u32 len;
754
755         if (*queued)
756                 goto out;
757
758         len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
759
760         /* this is the only place which holds both the socket's rs_lock
761          * and the connection's c_lock */
762         spin_lock_irqsave(&rs->rs_lock, flags);
763
764         /*
765          * If there is a little space in sndbuf, we don't queue anything,
766          * and userspace gets -EAGAIN. But poll() indicates there's send
767          * room. This can lead to bad behavior (spinning) if snd_bytes isn't
768          * freed up by incoming acks. So we check the *old* value of
769          * rs_snd_bytes here to allow the last msg to exceed the buffer,
770          * and poll() now knows no more data can be sent.
771          */
772         if (rs->rs_snd_bytes < rds_sk_sndbuf(rs)) {
773                 rs->rs_snd_bytes += len;
774
775                 /* let recv side know we are close to send space exhaustion.
776                  * This is probably not the optimal way to do it, as this
777                  * means we set the flag on *all* messages as soon as our
778                  * throughput hits a certain threshold.
779                  */
780                 if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2)
781                         __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
782
783                 list_add_tail(&rm->m_sock_item, &rs->rs_send_queue);
784                 set_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
785                 rds_message_addref(rm);
786                 rm->m_rs = rs;
787
788                 /* The code ordering is a little weird, but we're
789                    trying to minimize the time we hold c_lock */
790                 rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport, 0);
791                 rm->m_inc.i_conn = conn;
792                 rds_message_addref(rm);
793
794                 spin_lock(&conn->c_lock);
795                 rm->m_inc.i_hdr.h_sequence = cpu_to_be64(conn->c_next_tx_seq++);
796                 list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
797                 set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
798                 spin_unlock(&conn->c_lock);
799
800                 rdsdebug("queued msg %p len %d, rs %p bytes %d seq %llu\n",
801                          rm, len, rs, rs->rs_snd_bytes,
802                          (unsigned long long)be64_to_cpu(rm->m_inc.i_hdr.h_sequence));
803
804                 *queued = 1;
805         }
806
807         spin_unlock_irqrestore(&rs->rs_lock, flags);
808 out:
809         return *queued;
810 }
811
812 /*
813  * rds_message is getting to be quite complicated, and we'd like to allocate
814  * it all in one go. This figures out how big it needs to be up front.
815  */
816 static int rds_rm_size(struct msghdr *msg, int data_len)
817 {
818         struct cmsghdr *cmsg;
819         int size = 0;
820         int cmsg_groups = 0;
821         int retval;
822
823         for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
824                 if (!CMSG_OK(msg, cmsg))
825                         return -EINVAL;
826
827                 if (cmsg->cmsg_level != SOL_RDS)
828                         continue;
829
830                 switch (cmsg->cmsg_type) {
831                 case RDS_CMSG_RDMA_ARGS:
832                         cmsg_groups |= 1;
833                         retval = rds_rdma_extra_size(CMSG_DATA(cmsg));
834                         if (retval < 0)
835                                 return retval;
836                         size += retval;
837
838                         break;
839
840                 case RDS_CMSG_RDMA_DEST:
841                 case RDS_CMSG_RDMA_MAP:
842                         cmsg_groups |= 2;
843                         /* these are valid but do no add any size */
844                         break;
845
846                 case RDS_CMSG_ATOMIC_CSWP:
847                 case RDS_CMSG_ATOMIC_FADD:
848                 case RDS_CMSG_MASKED_ATOMIC_CSWP:
849                 case RDS_CMSG_MASKED_ATOMIC_FADD:
850                         cmsg_groups |= 1;
851                         size += sizeof(struct scatterlist);
852                         break;
853
854                 default:
855                         return -EINVAL;
856                 }
857
858         }
859
860         size += ceil(data_len, PAGE_SIZE) * sizeof(struct scatterlist);
861
862         /* Ensure (DEST, MAP) are never used with (ARGS, ATOMIC) */
863         if (cmsg_groups == 3)
864                 return -EINVAL;
865
866         return size;
867 }
868
869 static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
870                          struct msghdr *msg, int *allocated_mr)
871 {
872         struct cmsghdr *cmsg;
873         int ret = 0;
874
875         for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
876                 if (!CMSG_OK(msg, cmsg))
877                         return -EINVAL;
878
879                 if (cmsg->cmsg_level != SOL_RDS)
880                         continue;
881
882                 /* As a side effect, RDMA_DEST and RDMA_MAP will set
883                  * rm->rdma.m_rdma_cookie and rm->rdma.m_rdma_mr.
884                  */
885                 switch (cmsg->cmsg_type) {
886                 case RDS_CMSG_RDMA_ARGS:
887                         ret = rds_cmsg_rdma_args(rs, rm, cmsg);
888                         break;
889
890                 case RDS_CMSG_RDMA_DEST:
891                         ret = rds_cmsg_rdma_dest(rs, rm, cmsg);
892                         break;
893
894                 case RDS_CMSG_RDMA_MAP:
895                         ret = rds_cmsg_rdma_map(rs, rm, cmsg);
896                         if (!ret)
897                                 *allocated_mr = 1;
898                         break;
899                 case RDS_CMSG_ATOMIC_CSWP:
900                 case RDS_CMSG_ATOMIC_FADD:
901                 case RDS_CMSG_MASKED_ATOMIC_CSWP:
902                 case RDS_CMSG_MASKED_ATOMIC_FADD:
903                         ret = rds_cmsg_atomic(rs, rm, cmsg);
904                         break;
905
906                 default:
907                         return -EINVAL;
908                 }
909
910                 if (ret)
911                         break;
912         }
913
914         return ret;
915 }
916
917 int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
918                 size_t payload_len)
919 {
920         struct sock *sk = sock->sk;
921         struct rds_sock *rs = rds_sk_to_rs(sk);
922         struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name;
923         __be32 daddr;
924         __be16 dport;
925         struct rds_message *rm = NULL;
926         struct rds_connection *conn;
927         int ret = 0;
928         int queued = 0, allocated_mr = 0;
929         int nonblock = msg->msg_flags & MSG_DONTWAIT;
930         long timeo = sock_sndtimeo(sk, nonblock);
931
932         /* Mirror Linux UDP mirror of BSD error message compatibility */
933         /* XXX: Perhaps MSG_MORE someday */
934         if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) {
935                 printk(KERN_INFO "msg_flags 0x%08X\n", msg->msg_flags);
936                 ret = -EOPNOTSUPP;
937                 goto out;
938         }
939
940         if (msg->msg_namelen) {
941                 /* XXX fail non-unicast destination IPs? */
942                 if (msg->msg_namelen < sizeof(*usin) || usin->sin_family != AF_INET) {
943                         ret = -EINVAL;
944                         goto out;
945                 }
946                 daddr = usin->sin_addr.s_addr;
947                 dport = usin->sin_port;
948         } else {
949                 /* We only care about consistency with ->connect() */
950                 lock_sock(sk);
951                 daddr = rs->rs_conn_addr;
952                 dport = rs->rs_conn_port;
953                 release_sock(sk);
954         }
955
956         /* racing with another thread binding seems ok here */
957         if (daddr == 0 || rs->rs_bound_addr == 0) {
958                 ret = -ENOTCONN; /* XXX not a great errno */
959                 goto out;
960         }
961
962         /* size of rm including all sgs */
963         ret = rds_rm_size(msg, payload_len);
964         if (ret < 0)
965                 goto out;
966
967         rm = rds_message_alloc(ret, GFP_KERNEL);
968         if (!rm) {
969                 ret = -ENOMEM;
970                 goto out;
971         }
972
973         /* Attach data to the rm */
974         if (payload_len) {
975                 rm->data.op_sg = rds_message_alloc_sgs(rm, ceil(payload_len, PAGE_SIZE));
976                 ret = rds_message_copy_from_user(rm, msg->msg_iov, payload_len);
977                 if (ret)
978                         goto out;
979         }
980         rm->data.op_active = 1;
981
982         rm->m_daddr = daddr;
983
984         /* rds_conn_create has a spinlock that runs with IRQ off.
985          * Caching the conn in the socket helps a lot. */
986         if (rs->rs_conn && rs->rs_conn->c_faddr == daddr)
987                 conn = rs->rs_conn;
988         else {
989                 conn = rds_conn_create_outgoing(rs->rs_bound_addr, daddr,
990                                         rs->rs_transport,
991                                         sock->sk->sk_allocation);
992                 if (IS_ERR(conn)) {
993                         ret = PTR_ERR(conn);
994                         goto out;
995                 }
996                 rs->rs_conn = conn;
997         }
998
999         /* Parse any control messages the user may have included. */
1000         ret = rds_cmsg_send(rs, rm, msg, &allocated_mr);
1001         if (ret)
1002                 goto out;
1003
1004         if (rm->rdma.op_active && !conn->c_trans->xmit_rdma) {
1005                 if (printk_ratelimit())
1006                         printk(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",
1007                                &rm->rdma, conn->c_trans->xmit_rdma);
1008                 ret = -EOPNOTSUPP;
1009                 goto out;
1010         }
1011
1012         if (rm->atomic.op_active && !conn->c_trans->xmit_atomic) {
1013                 if (printk_ratelimit())
1014                         printk(KERN_NOTICE "atomic_op %p conn xmit_atomic %p\n",
1015                                &rm->atomic, conn->c_trans->xmit_atomic);
1016                 ret = -EOPNOTSUPP;
1017                 goto out;
1018         }
1019
1020         rds_conn_connect_if_down(conn);
1021
1022         ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);
1023         if (ret) {
1024                 rs->rs_seen_congestion = 1;
1025                 goto out;
1026         }
1027
1028         while (!rds_send_queue_rm(rs, conn, rm, rs->rs_bound_port,
1029                                   dport, &queued)) {
1030                 rds_stats_inc(s_send_queue_full);
1031                 /* XXX make sure this is reasonable */
1032                 if (payload_len > rds_sk_sndbuf(rs)) {
1033                         ret = -EMSGSIZE;
1034                         goto out;
1035                 }
1036                 if (nonblock) {
1037                         ret = -EAGAIN;
1038                         goto out;
1039                 }
1040
1041                 timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
1042                                         rds_send_queue_rm(rs, conn, rm,
1043                                                           rs->rs_bound_port,
1044                                                           dport,
1045                                                           &queued),
1046                                         timeo);
1047                 rdsdebug("sendmsg woke queued %d timeo %ld\n", queued, timeo);
1048                 if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
1049                         continue;
1050
1051                 ret = timeo;
1052                 if (ret == 0)
1053                         ret = -ETIMEDOUT;
1054                 goto out;
1055         }
1056
1057         /*
1058          * By now we've committed to the send.  We reuse rds_send_worker()
1059          * to retry sends in the rds thread if the transport asks us to.
1060          */
1061         rds_stats_inc(s_send_queued);
1062
1063         if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
1064                 rds_send_xmit(conn);
1065
1066         rds_message_put(rm);
1067         return payload_len;
1068
1069 out:
1070         /* If the user included a RDMA_MAP cmsg, we allocated a MR on the fly.
1071          * If the sendmsg goes through, we keep the MR. If it fails with EAGAIN
1072          * or in any other way, we need to destroy the MR again */
1073         if (allocated_mr)
1074                 rds_rdma_unuse(rs, rds_rdma_cookie_key(rm->m_rdma_cookie), 1);
1075
1076         if (rm)
1077                 rds_message_put(rm);
1078         return ret;
1079 }
1080
1081 /*
1082  * Reply to a ping packet.
1083  */
1084 int
1085 rds_send_pong(struct rds_connection *conn, __be16 dport)
1086 {
1087         struct rds_message *rm;
1088         unsigned long flags;
1089         int ret = 0;
1090
1091         rm = rds_message_alloc(0, GFP_ATOMIC);
1092         if (!rm) {
1093                 ret = -ENOMEM;
1094                 goto out;
1095         }
1096
1097         rm->m_daddr = conn->c_faddr;
1098         rm->data.op_active = 1;
1099
1100         rds_conn_connect_if_down(conn);
1101
1102         ret = rds_cong_wait(conn->c_fcong, dport, 1, NULL);
1103         if (ret)
1104                 goto out;
1105
1106         spin_lock_irqsave(&conn->c_lock, flags);
1107         list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
1108         set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
1109         rds_message_addref(rm);
1110         rm->m_inc.i_conn = conn;
1111
1112         rds_message_populate_header(&rm->m_inc.i_hdr, 0, dport,
1113                                     conn->c_next_tx_seq);
1114         conn->c_next_tx_seq++;
1115         spin_unlock_irqrestore(&conn->c_lock, flags);
1116
1117         rds_stats_inc(s_send_queued);
1118         rds_stats_inc(s_send_pong);
1119
1120         if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
1121                 rds_send_xmit(conn);
1122
1123         rds_message_put(rm);
1124         return 0;
1125
1126 out:
1127         if (rm)
1128                 rds_message_put(rm);
1129         return ret;
1130 }