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TOMOYO Linux Cross Reference
Linux/net/rds/send.c

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  1 /*
  2  * Copyright (c) 2006 Oracle.  All rights reserved.
  3  *
  4  * This software is available to you under a choice of one of two
  5  * licenses.  You may choose to be licensed under the terms of the GNU
  6  * General Public License (GPL) Version 2, available from the file
  7  * COPYING in the main directory of this source tree, or the
  8  * OpenIB.org BSD license below:
  9  *
 10  *     Redistribution and use in source and binary forms, with or
 11  *     without modification, are permitted provided that the following
 12  *     conditions are met:
 13  *
 14  *      - Redistributions of source code must retain the above
 15  *        copyright notice, this list of conditions and the following
 16  *        disclaimer.
 17  *
 18  *      - Redistributions in binary form must reproduce the above
 19  *        copyright notice, this list of conditions and the following
 20  *        disclaimer in the documentation and/or other materials
 21  *        provided with the distribution.
 22  *
 23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 30  * SOFTWARE.
 31  *
 32  */
 33 #include <linux/kernel.h>
 34 #include <linux/moduleparam.h>
 35 #include <linux/gfp.h>
 36 #include <net/sock.h>
 37 #include <linux/in.h>
 38 #include <linux/list.h>
 39 #include <linux/ratelimit.h>
 40 #include <linux/export.h>
 41 #include <linux/sizes.h>
 42 
 43 #include "rds.h"
 44 
 45 /* When transmitting messages in rds_send_xmit, we need to emerge from
 46  * time to time and briefly release the CPU. Otherwise the softlock watchdog
 47  * will kick our shin.
 48  * Also, it seems fairer to not let one busy connection stall all the
 49  * others.
 50  *
 51  * send_batch_count is the number of times we'll loop in send_xmit. Setting
 52  * it to 0 will restore the old behavior (where we looped until we had
 53  * drained the queue).
 54  */
 55 static int send_batch_count = SZ_1K;
 56 module_param(send_batch_count, int, 0444);
 57 MODULE_PARM_DESC(send_batch_count, " batch factor when working the send queue");
 58 
 59 static void rds_send_remove_from_sock(struct list_head *messages, int status);
 60 
 61 /*
 62  * Reset the send state.  Callers must ensure that this doesn't race with
 63  * rds_send_xmit().
 64  */
 65 void rds_send_path_reset(struct rds_conn_path *cp)
 66 {
 67         struct rds_message *rm, *tmp;
 68         unsigned long flags;
 69 
 70         if (cp->cp_xmit_rm) {
 71                 rm = cp->cp_xmit_rm;
 72                 cp->cp_xmit_rm = NULL;
 73                 /* Tell the user the RDMA op is no longer mapped by the
 74                  * transport. This isn't entirely true (it's flushed out
 75                  * independently) but as the connection is down, there's
 76                  * no ongoing RDMA to/from that memory */
 77                 rds_message_unmapped(rm);
 78                 rds_message_put(rm);
 79         }
 80 
 81         cp->cp_xmit_sg = 0;
 82         cp->cp_xmit_hdr_off = 0;
 83         cp->cp_xmit_data_off = 0;
 84         cp->cp_xmit_atomic_sent = 0;
 85         cp->cp_xmit_rdma_sent = 0;
 86         cp->cp_xmit_data_sent = 0;
 87 
 88         cp->cp_conn->c_map_queued = 0;
 89 
 90         cp->cp_unacked_packets = rds_sysctl_max_unacked_packets;
 91         cp->cp_unacked_bytes = rds_sysctl_max_unacked_bytes;
 92 
 93         /* Mark messages as retransmissions, and move them to the send q */
 94         spin_lock_irqsave(&cp->cp_lock, flags);
 95         list_for_each_entry_safe(rm, tmp, &cp->cp_retrans, m_conn_item) {
 96                 set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
 97                 set_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags);
 98         }
 99         list_splice_init(&cp->cp_retrans, &cp->cp_send_queue);
100         spin_unlock_irqrestore(&cp->cp_lock, flags);
101 }
102 EXPORT_SYMBOL_GPL(rds_send_path_reset);
103 
104 static int acquire_in_xmit(struct rds_conn_path *cp)
105 {
106         return test_and_set_bit(RDS_IN_XMIT, &cp->cp_flags) == 0;
107 }
108 
109 static void release_in_xmit(struct rds_conn_path *cp)
110 {
111         clear_bit(RDS_IN_XMIT, &cp->cp_flags);
112         smp_mb__after_atomic();
113         /*
114          * We don't use wait_on_bit()/wake_up_bit() because our waking is in a
115          * hot path and finding waiters is very rare.  We don't want to walk
116          * the system-wide hashed waitqueue buckets in the fast path only to
117          * almost never find waiters.
118          */
119         if (waitqueue_active(&cp->cp_waitq))
120                 wake_up_all(&cp->cp_waitq);
121 }
122 
123 /*
124  * We're making the conscious trade-off here to only send one message
125  * down the connection at a time.
126  *   Pro:
127  *      - tx queueing is a simple fifo list
128  *      - reassembly is optional and easily done by transports per conn
129  *      - no per flow rx lookup at all, straight to the socket
130  *      - less per-frag memory and wire overhead
131  *   Con:
132  *      - queued acks can be delayed behind large messages
133  *   Depends:
134  *      - small message latency is higher behind queued large messages
135  *      - large message latency isn't starved by intervening small sends
136  */
137 int rds_send_xmit(struct rds_conn_path *cp)
138 {
139         struct rds_connection *conn = cp->cp_conn;
140         struct rds_message *rm;
141         unsigned long flags;
142         unsigned int tmp;
143         struct scatterlist *sg;
144         int ret = 0;
145         LIST_HEAD(to_be_dropped);
146         int batch_count;
147         unsigned long send_gen = 0;
148 
149 restart:
150         batch_count = 0;
151 
152         /*
153          * sendmsg calls here after having queued its message on the send
154          * queue.  We only have one task feeding the connection at a time.  If
155          * another thread is already feeding the queue then we back off.  This
156          * avoids blocking the caller and trading per-connection data between
157          * caches per message.
158          */
159         if (!acquire_in_xmit(cp)) {
160                 rds_stats_inc(s_send_lock_contention);
161                 ret = -ENOMEM;
162                 goto out;
163         }
164 
165         /*
166          * we record the send generation after doing the xmit acquire.
167          * if someone else manages to jump in and do some work, we'll use
168          * this to avoid a goto restart farther down.
169          *
170          * The acquire_in_xmit() check above ensures that only one
171          * caller can increment c_send_gen at any time.
172          */
173         cp->cp_send_gen++;
174         send_gen = cp->cp_send_gen;
175 
176         /*
177          * rds_conn_shutdown() sets the conn state and then tests RDS_IN_XMIT,
178          * we do the opposite to avoid races.
179          */
180         if (!rds_conn_path_up(cp)) {
181                 release_in_xmit(cp);
182                 ret = 0;
183                 goto out;
184         }
185 
186         if (conn->c_trans->xmit_path_prepare)
187                 conn->c_trans->xmit_path_prepare(cp);
188 
189         /*
190          * spin trying to push headers and data down the connection until
191          * the connection doesn't make forward progress.
192          */
193         while (1) {
194 
195                 rm = cp->cp_xmit_rm;
196 
197                 /*
198                  * If between sending messages, we can send a pending congestion
199                  * map update.
200                  */
201                 if (!rm && test_and_clear_bit(0, &conn->c_map_queued)) {
202                         rm = rds_cong_update_alloc(conn);
203                         if (IS_ERR(rm)) {
204                                 ret = PTR_ERR(rm);
205                                 break;
206                         }
207                         rm->data.op_active = 1;
208                         rm->m_inc.i_conn_path = cp;
209                         rm->m_inc.i_conn = cp->cp_conn;
210 
211                         cp->cp_xmit_rm = rm;
212                 }
213 
214                 /*
215                  * If not already working on one, grab the next message.
216                  *
217                  * cp_xmit_rm holds a ref while we're sending this message down
218                  * the connction.  We can use this ref while holding the
219                  * send_sem.. rds_send_reset() is serialized with it.
220                  */
221                 if (!rm) {
222                         unsigned int len;
223 
224                         batch_count++;
225 
226                         /* we want to process as big a batch as we can, but
227                          * we also want to avoid softlockups.  If we've been
228                          * through a lot of messages, lets back off and see
229                          * if anyone else jumps in
230                          */
231                         if (batch_count >= send_batch_count)
232                                 goto over_batch;
233 
234                         spin_lock_irqsave(&cp->cp_lock, flags);
235 
236                         if (!list_empty(&cp->cp_send_queue)) {
237                                 rm = list_entry(cp->cp_send_queue.next,
238                                                 struct rds_message,
239                                                 m_conn_item);
240                                 rds_message_addref(rm);
241 
242                                 /*
243                                  * Move the message from the send queue to the retransmit
244                                  * list right away.
245                                  */
246                                 list_move_tail(&rm->m_conn_item,
247                                                &cp->cp_retrans);
248                         }
249 
250                         spin_unlock_irqrestore(&cp->cp_lock, flags);
251 
252                         if (!rm)
253                                 break;
254 
255                         /* Unfortunately, the way Infiniband deals with
256                          * RDMA to a bad MR key is by moving the entire
257                          * queue pair to error state. We cold possibly
258                          * recover from that, but right now we drop the
259                          * connection.
260                          * Therefore, we never retransmit messages with RDMA ops.
261                          */
262                         if (test_bit(RDS_MSG_FLUSH, &rm->m_flags) ||
263                             (rm->rdma.op_active &&
264                             test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags))) {
265                                 spin_lock_irqsave(&cp->cp_lock, flags);
266                                 if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags))
267                                         list_move(&rm->m_conn_item, &to_be_dropped);
268                                 spin_unlock_irqrestore(&cp->cp_lock, flags);
269                                 continue;
270                         }
271 
272                         /* Require an ACK every once in a while */
273                         len = ntohl(rm->m_inc.i_hdr.h_len);
274                         if (cp->cp_unacked_packets == 0 ||
275                             cp->cp_unacked_bytes < len) {
276                                 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
277 
278                                 cp->cp_unacked_packets =
279                                         rds_sysctl_max_unacked_packets;
280                                 cp->cp_unacked_bytes =
281                                         rds_sysctl_max_unacked_bytes;
282                                 rds_stats_inc(s_send_ack_required);
283                         } else {
284                                 cp->cp_unacked_bytes -= len;
285                                 cp->cp_unacked_packets--;
286                         }
287 
288                         cp->cp_xmit_rm = rm;
289                 }
290 
291                 /* The transport either sends the whole rdma or none of it */
292                 if (rm->rdma.op_active && !cp->cp_xmit_rdma_sent) {
293                         rm->m_final_op = &rm->rdma;
294                         /* The transport owns the mapped memory for now.
295                          * You can't unmap it while it's on the send queue
296                          */
297                         set_bit(RDS_MSG_MAPPED, &rm->m_flags);
298                         ret = conn->c_trans->xmit_rdma(conn, &rm->rdma);
299                         if (ret) {
300                                 clear_bit(RDS_MSG_MAPPED, &rm->m_flags);
301                                 wake_up_interruptible(&rm->m_flush_wait);
302                                 break;
303                         }
304                         cp->cp_xmit_rdma_sent = 1;
305 
306                 }
307 
308                 if (rm->atomic.op_active && !cp->cp_xmit_atomic_sent) {
309                         rm->m_final_op = &rm->atomic;
310                         /* The transport owns the mapped memory for now.
311                          * You can't unmap it while it's on the send queue
312                          */
313                         set_bit(RDS_MSG_MAPPED, &rm->m_flags);
314                         ret = conn->c_trans->xmit_atomic(conn, &rm->atomic);
315                         if (ret) {
316                                 clear_bit(RDS_MSG_MAPPED, &rm->m_flags);
317                                 wake_up_interruptible(&rm->m_flush_wait);
318                                 break;
319                         }
320                         cp->cp_xmit_atomic_sent = 1;
321 
322                 }
323 
324                 /*
325                  * A number of cases require an RDS header to be sent
326                  * even if there is no data.
327                  * We permit 0-byte sends; rds-ping depends on this.
328                  * However, if there are exclusively attached silent ops,
329                  * we skip the hdr/data send, to enable silent operation.
330                  */
331                 if (rm->data.op_nents == 0) {
332                         int ops_present;
333                         int all_ops_are_silent = 1;
334 
335                         ops_present = (rm->atomic.op_active || rm->rdma.op_active);
336                         if (rm->atomic.op_active && !rm->atomic.op_silent)
337                                 all_ops_are_silent = 0;
338                         if (rm->rdma.op_active && !rm->rdma.op_silent)
339                                 all_ops_are_silent = 0;
340 
341                         if (ops_present && all_ops_are_silent
342                             && !rm->m_rdma_cookie)
343                                 rm->data.op_active = 0;
344                 }
345 
346                 if (rm->data.op_active && !cp->cp_xmit_data_sent) {
347                         rm->m_final_op = &rm->data;
348 
349                         ret = conn->c_trans->xmit(conn, rm,
350                                                   cp->cp_xmit_hdr_off,
351                                                   cp->cp_xmit_sg,
352                                                   cp->cp_xmit_data_off);
353                         if (ret <= 0)
354                                 break;
355 
356                         if (cp->cp_xmit_hdr_off < sizeof(struct rds_header)) {
357                                 tmp = min_t(int, ret,
358                                             sizeof(struct rds_header) -
359                                             cp->cp_xmit_hdr_off);
360                                 cp->cp_xmit_hdr_off += tmp;
361                                 ret -= tmp;
362                         }
363 
364                         sg = &rm->data.op_sg[cp->cp_xmit_sg];
365                         while (ret) {
366                                 tmp = min_t(int, ret, sg->length -
367                                                       cp->cp_xmit_data_off);
368                                 cp->cp_xmit_data_off += tmp;
369                                 ret -= tmp;
370                                 if (cp->cp_xmit_data_off == sg->length) {
371                                         cp->cp_xmit_data_off = 0;
372                                         sg++;
373                                         cp->cp_xmit_sg++;
374                                         BUG_ON(ret != 0 && cp->cp_xmit_sg ==
375                                                rm->data.op_nents);
376                                 }
377                         }
378 
379                         if (cp->cp_xmit_hdr_off == sizeof(struct rds_header) &&
380                             (cp->cp_xmit_sg == rm->data.op_nents))
381                                 cp->cp_xmit_data_sent = 1;
382                 }
383 
384                 /*
385                  * A rm will only take multiple times through this loop
386                  * if there is a data op. Thus, if the data is sent (or there was
387                  * none), then we're done with the rm.
388                  */
389                 if (!rm->data.op_active || cp->cp_xmit_data_sent) {
390                         cp->cp_xmit_rm = NULL;
391                         cp->cp_xmit_sg = 0;
392                         cp->cp_xmit_hdr_off = 0;
393                         cp->cp_xmit_data_off = 0;
394                         cp->cp_xmit_rdma_sent = 0;
395                         cp->cp_xmit_atomic_sent = 0;
396                         cp->cp_xmit_data_sent = 0;
397 
398                         rds_message_put(rm);
399                 }
400         }
401 
402 over_batch:
403         if (conn->c_trans->xmit_path_complete)
404                 conn->c_trans->xmit_path_complete(cp);
405         release_in_xmit(cp);
406 
407         /* Nuke any messages we decided not to retransmit. */
408         if (!list_empty(&to_be_dropped)) {
409                 /* irqs on here, so we can put(), unlike above */
410                 list_for_each_entry(rm, &to_be_dropped, m_conn_item)
411                         rds_message_put(rm);
412                 rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED);
413         }
414 
415         /*
416          * Other senders can queue a message after we last test the send queue
417          * but before we clear RDS_IN_XMIT.  In that case they'd back off and
418          * not try and send their newly queued message.  We need to check the
419          * send queue after having cleared RDS_IN_XMIT so that their message
420          * doesn't get stuck on the send queue.
421          *
422          * If the transport cannot continue (i.e ret != 0), then it must
423          * call us when more room is available, such as from the tx
424          * completion handler.
425          *
426          * We have an extra generation check here so that if someone manages
427          * to jump in after our release_in_xmit, we'll see that they have done
428          * some work and we will skip our goto
429          */
430         if (ret == 0) {
431                 smp_mb();
432                 if ((test_bit(0, &conn->c_map_queued) ||
433                      !list_empty(&cp->cp_send_queue)) &&
434                     send_gen == cp->cp_send_gen) {
435                         rds_stats_inc(s_send_lock_queue_raced);
436                         if (batch_count < send_batch_count)
437                                 goto restart;
438                         queue_delayed_work(rds_wq, &cp->cp_send_w, 1);
439                 }
440         }
441 out:
442         return ret;
443 }
444 EXPORT_SYMBOL_GPL(rds_send_xmit);
445 
446 static void rds_send_sndbuf_remove(struct rds_sock *rs, struct rds_message *rm)
447 {
448         u32 len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
449 
450         assert_spin_locked(&rs->rs_lock);
451 
452         BUG_ON(rs->rs_snd_bytes < len);
453         rs->rs_snd_bytes -= len;
454 
455         if (rs->rs_snd_bytes == 0)
456                 rds_stats_inc(s_send_queue_empty);
457 }
458 
459 static inline int rds_send_is_acked(struct rds_message *rm, u64 ack,
460                                     is_acked_func is_acked)
461 {
462         if (is_acked)
463                 return is_acked(rm, ack);
464         return be64_to_cpu(rm->m_inc.i_hdr.h_sequence) <= ack;
465 }
466 
467 /*
468  * This is pretty similar to what happens below in the ACK
469  * handling code - except that we call here as soon as we get
470  * the IB send completion on the RDMA op and the accompanying
471  * message.
472  */
473 void rds_rdma_send_complete(struct rds_message *rm, int status)
474 {
475         struct rds_sock *rs = NULL;
476         struct rm_rdma_op *ro;
477         struct rds_notifier *notifier;
478         unsigned long flags;
479         unsigned int notify = 0;
480 
481         spin_lock_irqsave(&rm->m_rs_lock, flags);
482 
483         notify =  rm->rdma.op_notify | rm->data.op_notify;
484         ro = &rm->rdma;
485         if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) &&
486             ro->op_active && notify && ro->op_notifier) {
487                 notifier = ro->op_notifier;
488                 rs = rm->m_rs;
489                 sock_hold(rds_rs_to_sk(rs));
490 
491                 notifier->n_status = status;
492                 spin_lock(&rs->rs_lock);
493                 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
494                 spin_unlock(&rs->rs_lock);
495 
496                 ro->op_notifier = NULL;
497         }
498 
499         spin_unlock_irqrestore(&rm->m_rs_lock, flags);
500 
501         if (rs) {
502                 rds_wake_sk_sleep(rs);
503                 sock_put(rds_rs_to_sk(rs));
504         }
505 }
506 EXPORT_SYMBOL_GPL(rds_rdma_send_complete);
507 
508 /*
509  * Just like above, except looks at atomic op
510  */
511 void rds_atomic_send_complete(struct rds_message *rm, int status)
512 {
513         struct rds_sock *rs = NULL;
514         struct rm_atomic_op *ao;
515         struct rds_notifier *notifier;
516         unsigned long flags;
517 
518         spin_lock_irqsave(&rm->m_rs_lock, flags);
519 
520         ao = &rm->atomic;
521         if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags)
522             && ao->op_active && ao->op_notify && ao->op_notifier) {
523                 notifier = ao->op_notifier;
524                 rs = rm->m_rs;
525                 sock_hold(rds_rs_to_sk(rs));
526 
527                 notifier->n_status = status;
528                 spin_lock(&rs->rs_lock);
529                 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
530                 spin_unlock(&rs->rs_lock);
531 
532                 ao->op_notifier = NULL;
533         }
534 
535         spin_unlock_irqrestore(&rm->m_rs_lock, flags);
536 
537         if (rs) {
538                 rds_wake_sk_sleep(rs);
539                 sock_put(rds_rs_to_sk(rs));
540         }
541 }
542 EXPORT_SYMBOL_GPL(rds_atomic_send_complete);
543 
544 /*
545  * This is the same as rds_rdma_send_complete except we
546  * don't do any locking - we have all the ingredients (message,
547  * socket, socket lock) and can just move the notifier.
548  */
549 static inline void
550 __rds_send_complete(struct rds_sock *rs, struct rds_message *rm, int status)
551 {
552         struct rm_rdma_op *ro;
553         struct rm_atomic_op *ao;
554 
555         ro = &rm->rdma;
556         if (ro->op_active && ro->op_notify && ro->op_notifier) {
557                 ro->op_notifier->n_status = status;
558                 list_add_tail(&ro->op_notifier->n_list, &rs->rs_notify_queue);
559                 ro->op_notifier = NULL;
560         }
561 
562         ao = &rm->atomic;
563         if (ao->op_active && ao->op_notify && ao->op_notifier) {
564                 ao->op_notifier->n_status = status;
565                 list_add_tail(&ao->op_notifier->n_list, &rs->rs_notify_queue);
566                 ao->op_notifier = NULL;
567         }
568 
569         /* No need to wake the app - caller does this */
570 }
571 
572 /*
573  * This removes messages from the socket's list if they're on it.  The list
574  * argument must be private to the caller, we must be able to modify it
575  * without locks.  The messages must have a reference held for their
576  * position on the list.  This function will drop that reference after
577  * removing the messages from the 'messages' list regardless of if it found
578  * the messages on the socket list or not.
579  */
580 static void rds_send_remove_from_sock(struct list_head *messages, int status)
581 {
582         unsigned long flags;
583         struct rds_sock *rs = NULL;
584         struct rds_message *rm;
585 
586         while (!list_empty(messages)) {
587                 int was_on_sock = 0;
588 
589                 rm = list_entry(messages->next, struct rds_message,
590                                 m_conn_item);
591                 list_del_init(&rm->m_conn_item);
592 
593                 /*
594                  * If we see this flag cleared then we're *sure* that someone
595                  * else beat us to removing it from the sock.  If we race
596                  * with their flag update we'll get the lock and then really
597                  * see that the flag has been cleared.
598                  *
599                  * The message spinlock makes sure nobody clears rm->m_rs
600                  * while we're messing with it. It does not prevent the
601                  * message from being removed from the socket, though.
602                  */
603                 spin_lock_irqsave(&rm->m_rs_lock, flags);
604                 if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags))
605                         goto unlock_and_drop;
606 
607                 if (rs != rm->m_rs) {
608                         if (rs) {
609                                 rds_wake_sk_sleep(rs);
610                                 sock_put(rds_rs_to_sk(rs));
611                         }
612                         rs = rm->m_rs;
613                         if (rs)
614                                 sock_hold(rds_rs_to_sk(rs));
615                 }
616                 if (!rs)
617                         goto unlock_and_drop;
618                 spin_lock(&rs->rs_lock);
619 
620                 if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) {
621                         struct rm_rdma_op *ro = &rm->rdma;
622                         struct rds_notifier *notifier;
623 
624                         list_del_init(&rm->m_sock_item);
625                         rds_send_sndbuf_remove(rs, rm);
626 
627                         if (ro->op_active && ro->op_notifier &&
628                                (ro->op_notify || (ro->op_recverr && status))) {
629                                 notifier = ro->op_notifier;
630                                 list_add_tail(&notifier->n_list,
631                                                 &rs->rs_notify_queue);
632                                 if (!notifier->n_status)
633                                         notifier->n_status = status;
634                                 rm->rdma.op_notifier = NULL;
635                         }
636                         was_on_sock = 1;
637                         rm->m_rs = NULL;
638                 }
639                 spin_unlock(&rs->rs_lock);
640 
641 unlock_and_drop:
642                 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
643                 rds_message_put(rm);
644                 if (was_on_sock)
645                         rds_message_put(rm);
646         }
647 
648         if (rs) {
649                 rds_wake_sk_sleep(rs);
650                 sock_put(rds_rs_to_sk(rs));
651         }
652 }
653 
654 /*
655  * Transports call here when they've determined that the receiver queued
656  * messages up to, and including, the given sequence number.  Messages are
657  * moved to the retrans queue when rds_send_xmit picks them off the send
658  * queue. This means that in the TCP case, the message may not have been
659  * assigned the m_ack_seq yet - but that's fine as long as tcp_is_acked
660  * checks the RDS_MSG_HAS_ACK_SEQ bit.
661  */
662 void rds_send_path_drop_acked(struct rds_conn_path *cp, u64 ack,
663                               is_acked_func is_acked)
664 {
665         struct rds_message *rm, *tmp;
666         unsigned long flags;
667         LIST_HEAD(list);
668 
669         spin_lock_irqsave(&cp->cp_lock, flags);
670 
671         list_for_each_entry_safe(rm, tmp, &cp->cp_retrans, m_conn_item) {
672                 if (!rds_send_is_acked(rm, ack, is_acked))
673                         break;
674 
675                 list_move(&rm->m_conn_item, &list);
676                 clear_bit(RDS_MSG_ON_CONN, &rm->m_flags);
677         }
678 
679         /* order flag updates with spin locks */
680         if (!list_empty(&list))
681                 smp_mb__after_atomic();
682 
683         spin_unlock_irqrestore(&cp->cp_lock, flags);
684 
685         /* now remove the messages from the sock list as needed */
686         rds_send_remove_from_sock(&list, RDS_RDMA_SUCCESS);
687 }
688 EXPORT_SYMBOL_GPL(rds_send_path_drop_acked);
689 
690 void rds_send_drop_acked(struct rds_connection *conn, u64 ack,
691                          is_acked_func is_acked)
692 {
693         WARN_ON(conn->c_trans->t_mp_capable);
694         rds_send_path_drop_acked(&conn->c_path[0], ack, is_acked);
695 }
696 EXPORT_SYMBOL_GPL(rds_send_drop_acked);
697 
698 void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest)
699 {
700         struct rds_message *rm, *tmp;
701         struct rds_connection *conn;
702         struct rds_conn_path *cp;
703         unsigned long flags;
704         LIST_HEAD(list);
705 
706         /* get all the messages we're dropping under the rs lock */
707         spin_lock_irqsave(&rs->rs_lock, flags);
708 
709         list_for_each_entry_safe(rm, tmp, &rs->rs_send_queue, m_sock_item) {
710                 if (dest && (dest->sin_addr.s_addr != rm->m_daddr ||
711                              dest->sin_port != rm->m_inc.i_hdr.h_dport))
712                         continue;
713 
714                 list_move(&rm->m_sock_item, &list);
715                 rds_send_sndbuf_remove(rs, rm);
716                 clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
717         }
718 
719         /* order flag updates with the rs lock */
720         smp_mb__after_atomic();
721 
722         spin_unlock_irqrestore(&rs->rs_lock, flags);
723 
724         if (list_empty(&list))
725                 return;
726 
727         /* Remove the messages from the conn */
728         list_for_each_entry(rm, &list, m_sock_item) {
729 
730                 conn = rm->m_inc.i_conn;
731                 if (conn->c_trans->t_mp_capable)
732                         cp = rm->m_inc.i_conn_path;
733                 else
734                         cp = &conn->c_path[0];
735 
736                 spin_lock_irqsave(&cp->cp_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(&cp->cp_lock, flags);
744                         spin_lock_irqsave(&rm->m_rs_lock, flags);
745                         rm->m_rs = NULL;
746                         spin_unlock_irqrestore(&rm->m_rs_lock, flags);
747                         continue;
748                 }
749                 list_del_init(&rm->m_conn_item);
750                 spin_unlock_irqrestore(&cp->cp_lock, flags);
751 
752                 /*
753                  * Couldn't grab m_rs_lock in top loop (lock ordering),
754                  * but we can now.
755                  */
756                 spin_lock_irqsave(&rm->m_rs_lock, flags);
757 
758                 spin_lock(&rs->rs_lock);
759                 __rds_send_complete(rs, rm, RDS_RDMA_CANCELED);
760                 spin_unlock(&rs->rs_lock);
761 
762                 rm->m_rs = NULL;
763                 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
764 
765                 rds_message_put(rm);
766         }
767 
768         rds_wake_sk_sleep(rs);
769 
770         while (!list_empty(&list)) {
771                 rm = list_entry(list.next, struct rds_message, m_sock_item);
772                 list_del_init(&rm->m_sock_item);
773                 rds_message_wait(rm);
774 
775                 /* just in case the code above skipped this message
776                  * because RDS_MSG_ON_CONN wasn't set, run it again here
777                  * taking m_rs_lock is the only thing that keeps us
778                  * from racing with ack processing.
779                  */
780                 spin_lock_irqsave(&rm->m_rs_lock, flags);
781 
782                 spin_lock(&rs->rs_lock);
783                 __rds_send_complete(rs, rm, RDS_RDMA_CANCELED);
784                 spin_unlock(&rs->rs_lock);
785 
786                 rm->m_rs = NULL;
787                 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
788 
789                 rds_message_put(rm);
790         }
791 }
792 
793 /*
794  * we only want this to fire once so we use the callers 'queued'.  It's
795  * possible that another thread can race with us and remove the
796  * message from the flow with RDS_CANCEL_SENT_TO.
797  */
798 static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn,
799                              struct rds_conn_path *cp,
800                              struct rds_message *rm, __be16 sport,
801                              __be16 dport, int *queued)
802 {
803         unsigned long flags;
804         u32 len;
805 
806         if (*queued)
807                 goto out;
808 
809         len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
810 
811         /* this is the only place which holds both the socket's rs_lock
812          * and the connection's c_lock */
813         spin_lock_irqsave(&rs->rs_lock, flags);
814 
815         /*
816          * If there is a little space in sndbuf, we don't queue anything,
817          * and userspace gets -EAGAIN. But poll() indicates there's send
818          * room. This can lead to bad behavior (spinning) if snd_bytes isn't
819          * freed up by incoming acks. So we check the *old* value of
820          * rs_snd_bytes here to allow the last msg to exceed the buffer,
821          * and poll() now knows no more data can be sent.
822          */
823         if (rs->rs_snd_bytes < rds_sk_sndbuf(rs)) {
824                 rs->rs_snd_bytes += len;
825 
826                 /* let recv side know we are close to send space exhaustion.
827                  * This is probably not the optimal way to do it, as this
828                  * means we set the flag on *all* messages as soon as our
829                  * throughput hits a certain threshold.
830                  */
831                 if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2)
832                         __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
833 
834                 list_add_tail(&rm->m_sock_item, &rs->rs_send_queue);
835                 set_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
836                 rds_message_addref(rm);
837                 rm->m_rs = rs;
838 
839                 /* The code ordering is a little weird, but we're
840                    trying to minimize the time we hold c_lock */
841                 rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport, 0);
842                 rm->m_inc.i_conn = conn;
843                 rm->m_inc.i_conn_path = cp;
844                 rds_message_addref(rm);
845 
846                 spin_lock(&cp->cp_lock);
847                 rm->m_inc.i_hdr.h_sequence = cpu_to_be64(cp->cp_next_tx_seq++);
848                 list_add_tail(&rm->m_conn_item, &cp->cp_send_queue);
849                 set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
850                 spin_unlock(&cp->cp_lock);
851 
852                 rdsdebug("queued msg %p len %d, rs %p bytes %d seq %llu\n",
853                          rm, len, rs, rs->rs_snd_bytes,
854                          (unsigned long long)be64_to_cpu(rm->m_inc.i_hdr.h_sequence));
855 
856                 *queued = 1;
857         }
858 
859         spin_unlock_irqrestore(&rs->rs_lock, flags);
860 out:
861         return *queued;
862 }
863 
864 /*
865  * rds_message is getting to be quite complicated, and we'd like to allocate
866  * it all in one go. This figures out how big it needs to be up front.
867  */
868 static int rds_rm_size(struct msghdr *msg, int data_len)
869 {
870         struct cmsghdr *cmsg;
871         int size = 0;
872         int cmsg_groups = 0;
873         int retval;
874 
875         for_each_cmsghdr(cmsg, msg) {
876                 if (!CMSG_OK(msg, cmsg))
877                         return -EINVAL;
878 
879                 if (cmsg->cmsg_level != SOL_RDS)
880                         continue;
881 
882                 switch (cmsg->cmsg_type) {
883                 case RDS_CMSG_RDMA_ARGS:
884                         cmsg_groups |= 1;
885                         retval = rds_rdma_extra_size(CMSG_DATA(cmsg));
886                         if (retval < 0)
887                                 return retval;
888                         size += retval;
889 
890                         break;
891 
892                 case RDS_CMSG_RDMA_DEST:
893                 case RDS_CMSG_RDMA_MAP:
894                         cmsg_groups |= 2;
895                         /* these are valid but do no add any size */
896                         break;
897 
898                 case RDS_CMSG_ATOMIC_CSWP:
899                 case RDS_CMSG_ATOMIC_FADD:
900                 case RDS_CMSG_MASKED_ATOMIC_CSWP:
901                 case RDS_CMSG_MASKED_ATOMIC_FADD:
902                         cmsg_groups |= 1;
903                         size += sizeof(struct scatterlist);
904                         break;
905 
906                 default:
907                         return -EINVAL;
908                 }
909 
910         }
911 
912         size += ceil(data_len, PAGE_SIZE) * sizeof(struct scatterlist);
913 
914         /* Ensure (DEST, MAP) are never used with (ARGS, ATOMIC) */
915         if (cmsg_groups == 3)
916                 return -EINVAL;
917 
918         return size;
919 }
920 
921 static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
922                          struct msghdr *msg, int *allocated_mr)
923 {
924         struct cmsghdr *cmsg;
925         int ret = 0;
926 
927         for_each_cmsghdr(cmsg, msg) {
928                 if (!CMSG_OK(msg, cmsg))
929                         return -EINVAL;
930 
931                 if (cmsg->cmsg_level != SOL_RDS)
932                         continue;
933 
934                 /* As a side effect, RDMA_DEST and RDMA_MAP will set
935                  * rm->rdma.m_rdma_cookie and rm->rdma.m_rdma_mr.
936                  */
937                 switch (cmsg->cmsg_type) {
938                 case RDS_CMSG_RDMA_ARGS:
939                         ret = rds_cmsg_rdma_args(rs, rm, cmsg);
940                         break;
941 
942                 case RDS_CMSG_RDMA_DEST:
943                         ret = rds_cmsg_rdma_dest(rs, rm, cmsg);
944                         break;
945 
946                 case RDS_CMSG_RDMA_MAP:
947                         ret = rds_cmsg_rdma_map(rs, rm, cmsg);
948                         if (!ret)
949                                 *allocated_mr = 1;
950                         else if (ret == -ENODEV)
951                                 /* Accommodate the get_mr() case which can fail
952                                  * if connection isn't established yet.
953                                  */
954                                 ret = -EAGAIN;
955                         break;
956                 case RDS_CMSG_ATOMIC_CSWP:
957                 case RDS_CMSG_ATOMIC_FADD:
958                 case RDS_CMSG_MASKED_ATOMIC_CSWP:
959                 case RDS_CMSG_MASKED_ATOMIC_FADD:
960                         ret = rds_cmsg_atomic(rs, rm, cmsg);
961                         break;
962 
963                 default:
964                         return -EINVAL;
965                 }
966 
967                 if (ret)
968                         break;
969         }
970 
971         return ret;
972 }
973 
974 static void rds_send_ping(struct rds_connection *conn);
975 
976 static int rds_send_mprds_hash(struct rds_sock *rs, struct rds_connection *conn)
977 {
978         int hash;
979 
980         if (conn->c_npaths == 0)
981                 hash = RDS_MPATH_HASH(rs, RDS_MPATH_WORKERS);
982         else
983                 hash = RDS_MPATH_HASH(rs, conn->c_npaths);
984         if (conn->c_npaths == 0 && hash != 0) {
985                 rds_send_ping(conn);
986 
987                 if (conn->c_npaths == 0) {
988                         wait_event_interruptible(conn->c_hs_waitq,
989                                                  (conn->c_npaths != 0));
990                 }
991                 if (conn->c_npaths == 1)
992                         hash = 0;
993         }
994         return hash;
995 }
996 
997 static int rds_rdma_bytes(struct msghdr *msg, size_t *rdma_bytes)
998 {
999         struct rds_rdma_args *args;
1000         struct cmsghdr *cmsg;
1001 
1002         for_each_cmsghdr(cmsg, msg) {
1003                 if (!CMSG_OK(msg, cmsg))
1004                         return -EINVAL;
1005 
1006                 if (cmsg->cmsg_level != SOL_RDS)
1007                         continue;
1008 
1009                 if (cmsg->cmsg_type == RDS_CMSG_RDMA_ARGS) {
1010                         args = CMSG_DATA(cmsg);
1011                         *rdma_bytes += args->remote_vec.bytes;
1012                 }
1013         }
1014         return 0;
1015 }
1016 
1017 int rds_sendmsg(struct socket *sock, struct msghdr *msg, size_t payload_len)
1018 {
1019         struct sock *sk = sock->sk;
1020         struct rds_sock *rs = rds_sk_to_rs(sk);
1021         DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
1022         __be32 daddr;
1023         __be16 dport;
1024         struct rds_message *rm = NULL;
1025         struct rds_connection *conn;
1026         int ret = 0;
1027         int queued = 0, allocated_mr = 0;
1028         int nonblock = msg->msg_flags & MSG_DONTWAIT;
1029         long timeo = sock_sndtimeo(sk, nonblock);
1030         struct rds_conn_path *cpath;
1031         size_t total_payload_len = payload_len, rdma_payload_len = 0;
1032 
1033         /* Mirror Linux UDP mirror of BSD error message compatibility */
1034         /* XXX: Perhaps MSG_MORE someday */
1035         if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) {
1036                 ret = -EOPNOTSUPP;
1037                 goto out;
1038         }
1039 
1040         if (msg->msg_namelen) {
1041                 /* XXX fail non-unicast destination IPs? */
1042                 if (msg->msg_namelen < sizeof(*usin) || usin->sin_family != AF_INET) {
1043                         ret = -EINVAL;
1044                         goto out;
1045                 }
1046                 daddr = usin->sin_addr.s_addr;
1047                 dport = usin->sin_port;
1048         } else {
1049                 /* We only care about consistency with ->connect() */
1050                 lock_sock(sk);
1051                 daddr = rs->rs_conn_addr;
1052                 dport = rs->rs_conn_port;
1053                 release_sock(sk);
1054         }
1055 
1056         lock_sock(sk);
1057         if (daddr == 0 || rs->rs_bound_addr == 0) {
1058                 release_sock(sk);
1059                 ret = -ENOTCONN; /* XXX not a great errno */
1060                 goto out;
1061         }
1062         release_sock(sk);
1063 
1064         ret = rds_rdma_bytes(msg, &rdma_payload_len);
1065         if (ret)
1066                 goto out;
1067 
1068         total_payload_len += rdma_payload_len;
1069         if (max_t(size_t, payload_len, rdma_payload_len) > RDS_MAX_MSG_SIZE) {
1070                 ret = -EMSGSIZE;
1071                 goto out;
1072         }
1073 
1074         if (payload_len > rds_sk_sndbuf(rs)) {
1075                 ret = -EMSGSIZE;
1076                 goto out;
1077         }
1078 
1079         /* size of rm including all sgs */
1080         ret = rds_rm_size(msg, payload_len);
1081         if (ret < 0)
1082                 goto out;
1083 
1084         rm = rds_message_alloc(ret, GFP_KERNEL);
1085         if (!rm) {
1086                 ret = -ENOMEM;
1087                 goto out;
1088         }
1089 
1090         /* Attach data to the rm */
1091         if (payload_len) {
1092                 rm->data.op_sg = rds_message_alloc_sgs(rm, ceil(payload_len, PAGE_SIZE));
1093                 if (!rm->data.op_sg) {
1094                         ret = -ENOMEM;
1095                         goto out;
1096                 }
1097                 ret = rds_message_copy_from_user(rm, &msg->msg_iter);
1098                 if (ret)
1099                         goto out;
1100         }
1101         rm->data.op_active = 1;
1102 
1103         rm->m_daddr = daddr;
1104 
1105         /* rds_conn_create has a spinlock that runs with IRQ off.
1106          * Caching the conn in the socket helps a lot. */
1107         if (rs->rs_conn && rs->rs_conn->c_faddr == daddr)
1108                 conn = rs->rs_conn;
1109         else {
1110                 conn = rds_conn_create_outgoing(sock_net(sock->sk),
1111                                                 rs->rs_bound_addr, daddr,
1112                                         rs->rs_transport,
1113                                         sock->sk->sk_allocation);
1114                 if (IS_ERR(conn)) {
1115                         ret = PTR_ERR(conn);
1116                         goto out;
1117                 }
1118                 rs->rs_conn = conn;
1119         }
1120 
1121         /* Parse any control messages the user may have included. */
1122         ret = rds_cmsg_send(rs, rm, msg, &allocated_mr);
1123         if (ret) {
1124                 /* Trigger connection so that its ready for the next retry */
1125                 if (ret ==  -EAGAIN)
1126                         rds_conn_connect_if_down(conn);
1127                 goto out;
1128         }
1129 
1130         if (rm->rdma.op_active && !conn->c_trans->xmit_rdma) {
1131                 printk_ratelimited(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",
1132                                &rm->rdma, conn->c_trans->xmit_rdma);
1133                 ret = -EOPNOTSUPP;
1134                 goto out;
1135         }
1136 
1137         if (rm->atomic.op_active && !conn->c_trans->xmit_atomic) {
1138                 printk_ratelimited(KERN_NOTICE "atomic_op %p conn xmit_atomic %p\n",
1139                                &rm->atomic, conn->c_trans->xmit_atomic);
1140                 ret = -EOPNOTSUPP;
1141                 goto out;
1142         }
1143 
1144         if (conn->c_trans->t_mp_capable)
1145                 cpath = &conn->c_path[rds_send_mprds_hash(rs, conn)];
1146         else
1147                 cpath = &conn->c_path[0];
1148 
1149         rds_conn_path_connect_if_down(cpath);
1150 
1151         ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);
1152         if (ret) {
1153                 rs->rs_seen_congestion = 1;
1154                 goto out;
1155         }
1156         while (!rds_send_queue_rm(rs, conn, cpath, rm, rs->rs_bound_port,
1157                                   dport, &queued)) {
1158                 rds_stats_inc(s_send_queue_full);
1159 
1160                 if (nonblock) {
1161                         ret = -EAGAIN;
1162                         goto out;
1163                 }
1164 
1165                 timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
1166                                         rds_send_queue_rm(rs, conn, cpath, rm,
1167                                                           rs->rs_bound_port,
1168                                                           dport,
1169                                                           &queued),
1170                                         timeo);
1171                 rdsdebug("sendmsg woke queued %d timeo %ld\n", queued, timeo);
1172                 if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
1173                         continue;
1174 
1175                 ret = timeo;
1176                 if (ret == 0)
1177                         ret = -ETIMEDOUT;
1178                 goto out;
1179         }
1180 
1181         /*
1182          * By now we've committed to the send.  We reuse rds_send_worker()
1183          * to retry sends in the rds thread if the transport asks us to.
1184          */
1185         rds_stats_inc(s_send_queued);
1186 
1187         ret = rds_send_xmit(cpath);
1188         if (ret == -ENOMEM || ret == -EAGAIN)
1189                 queue_delayed_work(rds_wq, &cpath->cp_send_w, 1);
1190 
1191         rds_message_put(rm);
1192         return payload_len;
1193 
1194 out:
1195         /* If the user included a RDMA_MAP cmsg, we allocated a MR on the fly.
1196          * If the sendmsg goes through, we keep the MR. If it fails with EAGAIN
1197          * or in any other way, we need to destroy the MR again */
1198         if (allocated_mr)
1199                 rds_rdma_unuse(rs, rds_rdma_cookie_key(rm->m_rdma_cookie), 1);
1200 
1201         if (rm)
1202                 rds_message_put(rm);
1203         return ret;
1204 }
1205 
1206 /*
1207  * send out a probe. Can be shared by rds_send_ping,
1208  * rds_send_pong, rds_send_hb.
1209  * rds_send_hb should use h_flags
1210  *   RDS_FLAG_HB_PING|RDS_FLAG_ACK_REQUIRED
1211  * or
1212  *   RDS_FLAG_HB_PONG|RDS_FLAG_ACK_REQUIRED
1213  */
1214 static int
1215 rds_send_probe(struct rds_conn_path *cp, __be16 sport,
1216                __be16 dport, u8 h_flags)
1217 {
1218         struct rds_message *rm;
1219         unsigned long flags;
1220         int ret = 0;
1221 
1222         rm = rds_message_alloc(0, GFP_ATOMIC);
1223         if (!rm) {
1224                 ret = -ENOMEM;
1225                 goto out;
1226         }
1227 
1228         rm->m_daddr = cp->cp_conn->c_faddr;
1229         rm->data.op_active = 1;
1230 
1231         rds_conn_path_connect_if_down(cp);
1232 
1233         ret = rds_cong_wait(cp->cp_conn->c_fcong, dport, 1, NULL);
1234         if (ret)
1235                 goto out;
1236 
1237         spin_lock_irqsave(&cp->cp_lock, flags);
1238         list_add_tail(&rm->m_conn_item, &cp->cp_send_queue);
1239         set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
1240         rds_message_addref(rm);
1241         rm->m_inc.i_conn = cp->cp_conn;
1242         rm->m_inc.i_conn_path = cp;
1243 
1244         rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport,
1245                                     cp->cp_next_tx_seq);
1246         rm->m_inc.i_hdr.h_flags |= h_flags;
1247         cp->cp_next_tx_seq++;
1248 
1249         if (RDS_HS_PROBE(sport, dport) && cp->cp_conn->c_trans->t_mp_capable) {
1250                 u16 npaths = RDS_MPATH_WORKERS;
1251 
1252                 rds_message_add_extension(&rm->m_inc.i_hdr,
1253                                           RDS_EXTHDR_NPATHS, &npaths,
1254                                           sizeof(npaths));
1255                 rds_message_add_extension(&rm->m_inc.i_hdr,
1256                                           RDS_EXTHDR_GEN_NUM,
1257                                           &cp->cp_conn->c_my_gen_num,
1258                                           sizeof(u32));
1259         }
1260         spin_unlock_irqrestore(&cp->cp_lock, flags);
1261 
1262         rds_stats_inc(s_send_queued);
1263         rds_stats_inc(s_send_pong);
1264 
1265         /* schedule the send work on rds_wq */
1266         queue_delayed_work(rds_wq, &cp->cp_send_w, 1);
1267 
1268         rds_message_put(rm);
1269         return 0;
1270 
1271 out:
1272         if (rm)
1273                 rds_message_put(rm);
1274         return ret;
1275 }
1276 
1277 int
1278 rds_send_pong(struct rds_conn_path *cp, __be16 dport)
1279 {
1280         return rds_send_probe(cp, 0, dport, 0);
1281 }
1282 
1283 static void
1284 rds_send_ping(struct rds_connection *conn)
1285 {
1286         unsigned long flags;
1287         struct rds_conn_path *cp = &conn->c_path[0];
1288 
1289         spin_lock_irqsave(&cp->cp_lock, flags);
1290         if (conn->c_ping_triggered) {
1291                 spin_unlock_irqrestore(&cp->cp_lock, flags);
1292                 return;
1293         }
1294         conn->c_ping_triggered = 1;
1295         spin_unlock_irqrestore(&cp->cp_lock, flags);
1296         rds_send_probe(&conn->c_path[0], RDS_FLAG_PROBE_PORT, 0, 0);
1297 }
1298 

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