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/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 (rm->rdma.op_active &&
 263                             test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) {
 264                                 spin_lock_irqsave(&cp->cp_lock, flags);
 265                                 if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags))
 266                                         list_move(&rm->m_conn_item, &to_be_dropped);
 267                                 spin_unlock_irqrestore(&cp->cp_lock, flags);
 268                                 continue;
 269                         }
 270
 271                         /* Require an ACK every once in a while */
 272                         len = ntohl(rm->m_inc.i_hdr.h_len);
 273                         if (cp->cp_unacked_packets == 0 ||
 274                             cp->cp_unacked_bytes < len) {
 275                                 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
 276
 277                                 cp->cp_unacked_packets =
 278                                         rds_sysctl_max_unacked_packets;
 279                                 cp->cp_unacked_bytes =
 280                                         rds_sysctl_max_unacked_bytes;
 281                                 rds_stats_inc(s_send_ack_required);
 282                         } else {
 283                                 cp->cp_unacked_bytes -= len;
 284                                 cp->cp_unacked_packets--;
 285                         }
 286
 287                         cp->cp_xmit_rm = rm;
 288                 }
 289
 290                 /* The transport either sends the whole rdma or none of it */
 291                 if (rm->rdma.op_active && !cp->cp_xmit_rdma_sent) {
 292                         rm->m_final_op = &rm->rdma;
 293                         /* The transport owns the mapped memory for now.
 294                          * You can't unmap it while it's on the send queue
 295                          */
 296                         set_bit(RDS_MSG_MAPPED, &rm->m_flags);
 297                         ret = conn->c_trans->xmit_rdma(conn, &rm->rdma);
 298                         if (ret) {
 299                                 clear_bit(RDS_MSG_MAPPED, &rm->m_flags);
 300                                 wake_up_interruptible(&rm->m_flush_wait);
 301                                 break;
 302                         }
 303                         cp->cp_xmit_rdma_sent = 1;
 304
 305                 }
 306
 307                 if (rm->atomic.op_active && !cp->cp_xmit_atomic_sent) {
 308                         rm->m_final_op = &rm->atomic;
 309                         /* The transport owns the mapped memory for now.
 310                          * You can't unmap it while it's on the send queue
 311                          */
 312                         set_bit(RDS_MSG_MAPPED, &rm->m_flags);
 313                         ret = conn->c_trans->xmit_atomic(conn, &rm->atomic);
 314                         if (ret) {
 315                                 clear_bit(RDS_MSG_MAPPED, &rm->m_flags);
 316                                 wake_up_interruptible(&rm->m_flush_wait);
 317                                 break;
 318                         }
 319                         cp->cp_xmit_atomic_sent = 1;
 320
 321                 }
 322
 323                 /*
 324                  * A number of cases require an RDS header to be sent
 325                  * even if there is no data.
 326                  * We permit 0-byte sends; rds-ping depends on this.
 327                  * However, if there are exclusively attached silent ops,
 328                  * we skip the hdr/data send, to enable silent operation.
 329                  */
 330                 if (rm->data.op_nents == 0) {
 331                         int ops_present;
 332                         int all_ops_are_silent = 1;
 333
 334                         ops_present = (rm->atomic.op_active || rm->rdma.op_active);
 335                         if (rm->atomic.op_active && !rm->atomic.op_silent)
 336                                 all_ops_are_silent = 0;
 337                         if (rm->rdma.op_active && !rm->rdma.op_silent)
 338                                 all_ops_are_silent = 0;
 339
 340                         if (ops_present && all_ops_are_silent
 341                             && !rm->m_rdma_cookie)
 342                                 rm->data.op_active = 0;
 343                 }
 344
 345                 if (rm->data.op_active && !cp->cp_xmit_data_sent) {
 346                         rm->m_final_op = &rm->data;
 347
 348                         ret = conn->c_trans->xmit(conn, rm,
 349                                                   cp->cp_xmit_hdr_off,
 350                                                   cp->cp_xmit_sg,
 351                                                   cp->cp_xmit_data_off);
 352                         if (ret <= 0)
 353                                 break;
 354
 355                         if (cp->cp_xmit_hdr_off < sizeof(struct rds_header)) {
 356                                 tmp = min_t(int, ret,
 357                                             sizeof(struct rds_header) -
 358                                             cp->cp_xmit_hdr_off);
 359                                 cp->cp_xmit_hdr_off += tmp;
 360                                 ret -= tmp;
 361                         }
 362
 363                         sg = &rm->data.op_sg[cp->cp_xmit_sg];
 364                         while (ret) {
 365                                 tmp = min_t(int, ret, sg->length -
 366                                                       cp->cp_xmit_data_off);
 367                                 cp->cp_xmit_data_off += tmp;
 368                                 ret -= tmp;
 369                                 if (cp->cp_xmit_data_off == sg->length) {
 370                                         cp->cp_xmit_data_off = 0;
 371                                         sg++;
 372                                         cp->cp_xmit_sg++;
 373                                         BUG_ON(ret != 0 && cp->cp_xmit_sg ==
 374                                                rm->data.op_nents);
 375                                 }
 376                         }
 377
 378                         if (cp->cp_xmit_hdr_off == sizeof(struct rds_header) &&
 379                             (cp->cp_xmit_sg == rm->data.op_nents))
 380                                 cp->cp_xmit_data_sent = 1;
 381                 }
 382
 383                 /*
 384                  * A rm will only take multiple times through this loop
 385                  * if there is a data op. Thus, if the data is sent (or there was
 386                  * none), then we're done with the rm.
 387                  */
 388                 if (!rm->data.op_active || cp->cp_xmit_data_sent) {
 389                         cp->cp_xmit_rm = NULL;
 390                         cp->cp_xmit_sg = 0;
 391                         cp->cp_xmit_hdr_off = 0;
 392                         cp->cp_xmit_data_off = 0;
 393                         cp->cp_xmit_rdma_sent = 0;
 394                         cp->cp_xmit_atomic_sent = 0;
 395                         cp->cp_xmit_data_sent = 0;
 396
 397                         rds_message_put(rm);
 398                 }
 399         }
 400
 401 over_batch:
 402         if (conn->c_trans->xmit_path_complete)
 403                 conn->c_trans->xmit_path_complete(cp);
 404         release_in_xmit(cp);
 405
 406         /* Nuke any messages we decided not to retransmit. */
 407         if (!list_empty(&to_be_dropped)) {
 408                 /* irqs on here, so we can put(), unlike above */
 409                 list_for_each_entry(rm, &to_be_dropped, m_conn_item)
 410                         rds_message_put(rm);
 411                 rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED);
 412         }
 413
 414         /*
 415          * Other senders can queue a message after we last test the send queue
 416          * but before we clear RDS_IN_XMIT.  In that case they'd back off and
 417          * not try and send their newly queued message.  We need to check the
 418          * send queue after having cleared RDS_IN_XMIT so that their message
 419          * doesn't get stuck on the send queue.
 420          *
 421          * If the transport cannot continue (i.e ret != 0), then it must
 422          * call us when more room is available, such as from the tx
 423          * completion handler.
 424          *
 425          * We have an extra generation check here so that if someone manages
 426          * to jump in after our release_in_xmit, we'll see that they have done
 427          * some work and we will skip our goto
 428          */
 429         if (ret == 0) {
 430                 smp_mb();
 431                 if ((test_bit(0, &conn->c_map_queued) ||
 432                      !list_empty(&cp->cp_send_queue)) &&
 433                     send_gen == cp->cp_send_gen) {
 434                         rds_stats_inc(s_send_lock_queue_raced);
 435                         if (batch_count < send_batch_count)
 436                                 goto restart;
 437                         queue_delayed_work(rds_wq, &cp->cp_send_w, 1);
 438                 }
 439         }
 440 out:
 441         return ret;
 442 }
 443 EXPORT_SYMBOL_GPL(rds_send_xmit);
 444
 445 static void rds_send_sndbuf_remove(struct rds_sock *rs, struct rds_message *rm)
 446 {
 447         u32 len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
 448
 449         assert_spin_locked(&rs->rs_lock);
 450
 451         BUG_ON(rs->rs_snd_bytes < len);
 452         rs->rs_snd_bytes -= len;
 453
 454         if (rs->rs_snd_bytes == 0)
 455                 rds_stats_inc(s_send_queue_empty);
 456 }
 457
 458 static inline int rds_send_is_acked(struct rds_message *rm, u64 ack,
 459                                     is_acked_func is_acked)
 460 {
 461         if (is_acked)
 462                 return is_acked(rm, ack);
 463         return be64_to_cpu(rm->m_inc.i_hdr.h_sequence) <= ack;
 464 }
 465
 466 /*
 467  * This is pretty similar to what happens below in the ACK
 468  * handling code - except that we call here as soon as we get
 469  * the IB send completion on the RDMA op and the accompanying
 470  * message.
 471  */
 472 void rds_rdma_send_complete(struct rds_message *rm, int status)
 473 {
 474         struct rds_sock *rs = NULL;
 475         struct rm_rdma_op *ro;
 476         struct rds_notifier *notifier;
 477         unsigned long flags;
 478
 479         spin_lock_irqsave(&rm->m_rs_lock, flags);
 480
 481         ro = &rm->rdma;
 482         if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) &&
 483             ro->op_active && ro->op_notify && ro->op_notifier) {
 484                 notifier = ro->op_notifier;
 485                 rs = rm->m_rs;
 486                 sock_hold(rds_rs_to_sk(rs));
 487
 488                 notifier->n_status = status;
 489                 spin_lock(&rs->rs_lock);
 490                 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
 491                 spin_unlock(&rs->rs_lock);
 492
 493                 ro->op_notifier = NULL;
 494         }
 495
 496         spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 497
 498         if (rs) {
 499                 rds_wake_sk_sleep(rs);
 500                 sock_put(rds_rs_to_sk(rs));
 501         }
 502 }
 503 EXPORT_SYMBOL_GPL(rds_rdma_send_complete);
 504
 505 /*
 506  * Just like above, except looks at atomic op
 507  */
 508 void rds_atomic_send_complete(struct rds_message *rm, int status)
 509 {
 510         struct rds_sock *rs = NULL;
 511         struct rm_atomic_op *ao;
 512         struct rds_notifier *notifier;
 513         unsigned long flags;
 514
 515         spin_lock_irqsave(&rm->m_rs_lock, flags);
 516
 517         ao = &rm->atomic;
 518         if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags)
 519             && ao->op_active && ao->op_notify && ao->op_notifier) {
 520                 notifier = ao->op_notifier;
 521                 rs = rm->m_rs;
 522                 sock_hold(rds_rs_to_sk(rs));
 523
 524                 notifier->n_status = status;
 525                 spin_lock(&rs->rs_lock);
 526                 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
 527                 spin_unlock(&rs->rs_lock);
 528
 529                 ao->op_notifier = NULL;
 530         }
 531
 532         spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 533
 534         if (rs) {
 535                 rds_wake_sk_sleep(rs);
 536                 sock_put(rds_rs_to_sk(rs));
 537         }
 538 }
 539 EXPORT_SYMBOL_GPL(rds_atomic_send_complete);
 540
 541 /*
 542  * This is the same as rds_rdma_send_complete except we
 543  * don't do any locking - we have all the ingredients (message,
 544  * socket, socket lock) and can just move the notifier.
 545  */
 546 static inline void
 547 __rds_send_complete(struct rds_sock *rs, struct rds_message *rm, int status)
 548 {
 549         struct rm_rdma_op *ro;
 550         struct rm_atomic_op *ao;
 551
 552         ro = &rm->rdma;
 553         if (ro->op_active && ro->op_notify && ro->op_notifier) {
 554                 ro->op_notifier->n_status = status;
 555                 list_add_tail(&ro->op_notifier->n_list, &rs->rs_notify_queue);
 556                 ro->op_notifier = NULL;
 557         }
 558
 559         ao = &rm->atomic;
 560         if (ao->op_active && ao->op_notify && ao->op_notifier) {
 561                 ao->op_notifier->n_status = status;
 562                 list_add_tail(&ao->op_notifier->n_list, &rs->rs_notify_queue);
 563                 ao->op_notifier = NULL;
 564         }
 565
 566         /* No need to wake the app - caller does this */
 567 }
 568
 569 /*
 570  * This removes messages from the socket's list if they're on it.  The list
 571  * argument must be private to the caller, we must be able to modify it
 572  * without locks.  The messages must have a reference held for their
 573  * position on the list.  This function will drop that reference after
 574  * removing the messages from the 'messages' list regardless of if it found
 575  * the messages on the socket list or not.
 576  */
 577 static void rds_send_remove_from_sock(struct list_head *messages, int status)
 578 {
 579         unsigned long flags;
 580         struct rds_sock *rs = NULL;
 581         struct rds_message *rm;
 582
 583         while (!list_empty(messages)) {
 584                 int was_on_sock = 0;
 585
 586                 rm = list_entry(messages->next, struct rds_message,
 587                                 m_conn_item);
 588                 list_del_init(&rm->m_conn_item);
 589
 590                 /*
 591                  * If we see this flag cleared then we're *sure* that someone
 592                  * else beat us to removing it from the sock.  If we race
 593                  * with their flag update we'll get the lock and then really
 594                  * see that the flag has been cleared.
 595                  *
 596                  * The message spinlock makes sure nobody clears rm->m_rs
 597                  * while we're messing with it. It does not prevent the
 598                  * message from being removed from the socket, though.
 599                  */
 600                 spin_lock_irqsave(&rm->m_rs_lock, flags);
 601                 if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags))
 602                         goto unlock_and_drop;
 603
 604                 if (rs != rm->m_rs) {
 605                         if (rs) {
 606                                 rds_wake_sk_sleep(rs);
 607                                 sock_put(rds_rs_to_sk(rs));
 608                         }
 609                         rs = rm->m_rs;
 610                         if (rs)
 611                                 sock_hold(rds_rs_to_sk(rs));
 612                 }
 613                 if (!rs)
 614                         goto unlock_and_drop;
 615                 spin_lock(&rs->rs_lock);
 616
 617                 if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) {
 618                         struct rm_rdma_op *ro = &rm->rdma;
 619                         struct rds_notifier *notifier;
 620
 621                         list_del_init(&rm->m_sock_item);
 622                         rds_send_sndbuf_remove(rs, rm);
 623
 624                         if (ro->op_active && ro->op_notifier &&
 625                                (ro->op_notify || (ro->op_recverr && status))) {
 626                                 notifier = ro->op_notifier;
 627                                 list_add_tail(&notifier->n_list,
 628                                                 &rs->rs_notify_queue);
 629                                 if (!notifier->n_status)
 630                                         notifier->n_status = status;
 631                                 rm->rdma.op_notifier = NULL;
 632                         }
 633                         was_on_sock = 1;
 634                         rm->m_rs = NULL;
 635                 }
 636                 spin_unlock(&rs->rs_lock);
 637
 638 unlock_and_drop:
 639                 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 640                 rds_message_put(rm);
 641                 if (was_on_sock)
 642                         rds_message_put(rm);
 643         }
 644
 645         if (rs) {
 646                 rds_wake_sk_sleep(rs);
 647                 sock_put(rds_rs_to_sk(rs));
 648         }
 649 }
 650
 651 /*
 652  * Transports call here when they've determined that the receiver queued
 653  * messages up to, and including, the given sequence number.  Messages are
 654  * moved to the retrans queue when rds_send_xmit picks them off the send
 655  * queue. This means that in the TCP case, the message may not have been
 656  * assigned the m_ack_seq yet - but that's fine as long as tcp_is_acked
 657  * checks the RDS_MSG_HAS_ACK_SEQ bit.
 658  */
 659 void rds_send_path_drop_acked(struct rds_conn_path *cp, u64 ack,
 660                               is_acked_func is_acked)
 661 {
 662         struct rds_message *rm, *tmp;
 663         unsigned long flags;
 664         LIST_HEAD(list);
 665
 666         spin_lock_irqsave(&cp->cp_lock, flags);
 667
 668         list_for_each_entry_safe(rm, tmp, &cp->cp_retrans, m_conn_item) {
 669                 if (!rds_send_is_acked(rm, ack, is_acked))
 670                         break;
 671
 672                 list_move(&rm->m_conn_item, &list);
 673                 clear_bit(RDS_MSG_ON_CONN, &rm->m_flags);
 674         }
 675
 676         /* order flag updates with spin locks */
 677         if (!list_empty(&list))
 678                 smp_mb__after_atomic();
 679
 680         spin_unlock_irqrestore(&cp->cp_lock, flags);
 681
 682         /* now remove the messages from the sock list as needed */
 683         rds_send_remove_from_sock(&list, RDS_RDMA_SUCCESS);
 684 }
 685 EXPORT_SYMBOL_GPL(rds_send_path_drop_acked);
 686
 687 void rds_send_drop_acked(struct rds_connection *conn, u64 ack,
 688                          is_acked_func is_acked)
 689 {
 690         WARN_ON(conn->c_trans->t_mp_capable);
 691         rds_send_path_drop_acked(&conn->c_path[0], ack, is_acked);
 692 }
 693 EXPORT_SYMBOL_GPL(rds_send_drop_acked);
 694
 695 void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest)
 696 {
 697         struct rds_message *rm, *tmp;
 698         struct rds_connection *conn;
 699         struct rds_conn_path *cp;
 700         unsigned long flags;
 701         LIST_HEAD(list);
 702
 703         /* get all the messages we're dropping under the rs lock */
 704         spin_lock_irqsave(&rs->rs_lock, flags);
 705
 706         list_for_each_entry_safe(rm, tmp, &rs->rs_send_queue, m_sock_item) {
 707                 if (dest && (dest->sin_addr.s_addr != rm->m_daddr ||
 708                              dest->sin_port != rm->m_inc.i_hdr.h_dport))
 709                         continue;
 710
 711                 list_move(&rm->m_sock_item, &list);
 712                 rds_send_sndbuf_remove(rs, rm);
 713                 clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
 714         }
 715
 716         /* order flag updates with the rs lock */
 717         smp_mb__after_atomic();
 718
 719         spin_unlock_irqrestore(&rs->rs_lock, flags);
 720
 721         if (list_empty(&list))
 722                 return;
 723
 724         /* Remove the messages from the conn */
 725         list_for_each_entry(rm, &list, m_sock_item) {
 726
 727                 conn = rm->m_inc.i_conn;
 728                 if (conn->c_trans->t_mp_capable)
 729                         cp = rm->m_inc.i_conn_path;
 730                 else
 731                         cp = &conn->c_path[0];
 732
 733                 spin_lock_irqsave(&cp->cp_lock, flags);
 734                 /*
 735                  * Maybe someone else beat us to removing rm from the conn.
 736                  * If we race with their flag update we'll get the lock and
 737                  * then really see that the flag has been cleared.
 738                  */
 739                 if (!test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) {
 740                         spin_unlock_irqrestore(&cp->cp_lock, flags);
 741                         spin_lock_irqsave(&rm->m_rs_lock, flags);
 742                         rm->m_rs = NULL;
 743                         spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 744                         continue;
 745                 }
 746                 list_del_init(&rm->m_conn_item);
 747                 spin_unlock_irqrestore(&cp->cp_lock, flags);
 748
 749                 /*
 750                  * Couldn't grab m_rs_lock in top loop (lock ordering),
 751                  * but we can now.
 752                  */
 753                 spin_lock_irqsave(&rm->m_rs_lock, flags);
 754
 755                 spin_lock(&rs->rs_lock);
 756                 __rds_send_complete(rs, rm, RDS_RDMA_CANCELED);
 757                 spin_unlock(&rs->rs_lock);
 758
 759                 rm->m_rs = NULL;
 760                 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 761
 762                 rds_message_put(rm);
 763         }
 764
 765         rds_wake_sk_sleep(rs);
 766
 767         while (!list_empty(&list)) {
 768                 rm = list_entry(list.next, struct rds_message, m_sock_item);
 769                 list_del_init(&rm->m_sock_item);
 770                 rds_message_wait(rm);
 771
 772                 /* just in case the code above skipped this message
 773                  * because RDS_MSG_ON_CONN wasn't set, run it again here
 774                  * taking m_rs_lock is the only thing that keeps us
 775                  * from racing with ack processing.
 776                  */
 777                 spin_lock_irqsave(&rm->m_rs_lock, flags);
 778
 779                 spin_lock(&rs->rs_lock);
 780                 __rds_send_complete(rs, rm, RDS_RDMA_CANCELED);
 781                 spin_unlock(&rs->rs_lock);
 782
 783                 rm->m_rs = NULL;
 784                 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 785
 786                 rds_message_put(rm);
 787         }
 788 }
 789
 790 /*
 791  * we only want this to fire once so we use the callers 'queued'.  It's
 792  * possible that another thread can race with us and remove the
 793  * message from the flow with RDS_CANCEL_SENT_TO.
 794  */
 795 static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn,
 796                              struct rds_conn_path *cp,
 797                              struct rds_message *rm, __be16 sport,
 798                              __be16 dport, int *queued)
 799 {
 800         unsigned long flags;
 801         u32 len;
 802
 803         if (*queued)
 804                 goto out;
 805
 806         len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
 807
 808         /* this is the only place which holds both the socket's rs_lock
 809          * and the connection's c_lock */
 810         spin_lock_irqsave(&rs->rs_lock, flags);
 811
 812         /*
 813          * If there is a little space in sndbuf, we don't queue anything,
 814          * and userspace gets -EAGAIN. But poll() indicates there's send
 815          * room. This can lead to bad behavior (spinning) if snd_bytes isn't
 816          * freed up by incoming acks. So we check the *old* value of
 817          * rs_snd_bytes here to allow the last msg to exceed the buffer,
 818          * and poll() now knows no more data can be sent.
 819          */
 820         if (rs->rs_snd_bytes < rds_sk_sndbuf(rs)) {
 821                 rs->rs_snd_bytes += len;
 822
 823                 /* let recv side know we are close to send space exhaustion.
 824                  * This is probably not the optimal way to do it, as this
 825                  * means we set the flag on *all* messages as soon as our
 826                  * throughput hits a certain threshold.
 827                  */
 828                 if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2)
 829                         __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
 830
 831                 list_add_tail(&rm->m_sock_item, &rs->rs_send_queue);
 832                 set_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
 833                 rds_message_addref(rm);
 834                 rm->m_rs = rs;
 835
 836                 /* The code ordering is a little weird, but we're
 837                    trying to minimize the time we hold c_lock */
 838                 rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport, 0);
 839                 rm->m_inc.i_conn = conn;
 840                 rm->m_inc.i_conn_path = cp;
 841                 rds_message_addref(rm);
 842
 843                 spin_lock(&cp->cp_lock);
 844                 rm->m_inc.i_hdr.h_sequence = cpu_to_be64(cp->cp_next_tx_seq++);
 845                 list_add_tail(&rm->m_conn_item, &cp->cp_send_queue);
 846                 set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
 847                 spin_unlock(&cp->cp_lock);
 848
 849                 rdsdebug("queued msg %p len %d, rs %p bytes %d seq %llu\n",
 850                          rm, len, rs, rs->rs_snd_bytes,
 851                          (unsigned long long)be64_to_cpu(rm->m_inc.i_hdr.h_sequence));
 852
 853                 *queued = 1;
 854         }
 855
 856         spin_unlock_irqrestore(&rs->rs_lock, flags);
 857 out:
 858         return *queued;
 859 }
 860
 861 /*
 862  * rds_message is getting to be quite complicated, and we'd like to allocate
 863  * it all in one go. This figures out how big it needs to be up front.
 864  */
 865 static int rds_rm_size(struct msghdr *msg, int data_len)
 866 {
 867         struct cmsghdr *cmsg;
 868         int size = 0;
 869         int cmsg_groups = 0;
 870         int retval;
 871
 872         for_each_cmsghdr(cmsg, msg) {
 873                 if (!CMSG_OK(msg, cmsg))
 874                         return -EINVAL;
 875
 876                 if (cmsg->cmsg_level != SOL_RDS)
 877                         continue;
 878
 879                 switch (cmsg->cmsg_type) {
 880                 case RDS_CMSG_RDMA_ARGS:
 881                         cmsg_groups |= 1;
 882                         retval = rds_rdma_extra_size(CMSG_DATA(cmsg));
 883                         if (retval < 0)
 884                                 return retval;
 885                         size += retval;
 886
 887                         break;
 888
 889                 case RDS_CMSG_RDMA_DEST:
 890                 case RDS_CMSG_RDMA_MAP:
 891                         cmsg_groups |= 2;
 892                         /* these are valid but do no add any size */
 893                         break;
 894
 895                 case RDS_CMSG_ATOMIC_CSWP:
 896                 case RDS_CMSG_ATOMIC_FADD:
 897                 case RDS_CMSG_MASKED_ATOMIC_CSWP:
 898                 case RDS_CMSG_MASKED_ATOMIC_FADD:
 899                         cmsg_groups |= 1;
 900                         size += sizeof(struct scatterlist);
 901                         break;
 902
 903                 default:
 904                         return -EINVAL;
 905                 }
 906
 907         }
 908
 909         size += ceil(data_len, PAGE_SIZE) * sizeof(struct scatterlist);
 910
 911         /* Ensure (DEST, MAP) are never used with (ARGS, ATOMIC) */
 912         if (cmsg_groups == 3)
 913                 return -EINVAL;
 914
 915         return size;
 916 }
 917
 918 static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
 919                          struct msghdr *msg, int *allocated_mr)
 920 {
 921         struct cmsghdr *cmsg;
 922         int ret = 0;
 923
 924         for_each_cmsghdr(cmsg, msg) {
 925                 if (!CMSG_OK(msg, cmsg))
 926                         return -EINVAL;
 927
 928                 if (cmsg->cmsg_level != SOL_RDS)
 929                         continue;
 930
 931                 /* As a side effect, RDMA_DEST and RDMA_MAP will set
 932                  * rm->rdma.m_rdma_cookie and rm->rdma.m_rdma_mr.
 933                  */
 934                 switch (cmsg->cmsg_type) {
 935                 case RDS_CMSG_RDMA_ARGS:
 936                         ret = rds_cmsg_rdma_args(rs, rm, cmsg);
 937                         break;
 938
 939                 case RDS_CMSG_RDMA_DEST:
 940                         ret = rds_cmsg_rdma_dest(rs, rm, cmsg);
 941                         break;
 942
 943                 case RDS_CMSG_RDMA_MAP:
 944                         ret = rds_cmsg_rdma_map(rs, rm, cmsg);
 945                         if (!ret)
 946                                 *allocated_mr = 1;
 947                         break;
 948                 case RDS_CMSG_ATOMIC_CSWP:
 949                 case RDS_CMSG_ATOMIC_FADD:
 950                 case RDS_CMSG_MASKED_ATOMIC_CSWP:
 951                 case RDS_CMSG_MASKED_ATOMIC_FADD:
 952                         ret = rds_cmsg_atomic(rs, rm, cmsg);
 953                         break;
 954
 955                 default:
 956                         return -EINVAL;
 957                 }
 958
 959                 if (ret)
 960                         break;
 961         }
 962
 963         return ret;
 964 }
 965
 966 static void rds_send_ping(struct rds_connection *conn);
 967
 968 static int rds_send_mprds_hash(struct rds_sock *rs, struct rds_connection *conn)
 969 {
 970         int hash;
 971
 972         if (conn->c_npaths == 0)
 973                 hash = RDS_MPATH_HASH(rs, RDS_MPATH_WORKERS);
 974         else
 975                 hash = RDS_MPATH_HASH(rs, conn->c_npaths);
 976         if (conn->c_npaths == 0 && hash != 0) {
 977                 rds_send_ping(conn);
 978
 979                 if (conn->c_npaths == 0) {
 980                         wait_event_interruptible(conn->c_hs_waitq,
 981                                                  (conn->c_npaths != 0));
 982                 }
 983                 if (conn->c_npaths == 1)
 984                         hash = 0;
 985         }
 986         return hash;
 987 }
 988
 989 int rds_sendmsg(struct socket *sock, struct msghdr *msg, size_t payload_len)
 990 {
 991         struct sock *sk = sock->sk;
 992         struct rds_sock *rs = rds_sk_to_rs(sk);
 993         DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
 994         __be32 daddr;
 995         __be16 dport;
 996         struct rds_message *rm = NULL;
 997         struct rds_connection *conn;
 998         int ret = 0;
 999         int queued = 0, allocated_mr = 0;
1000         int nonblock = msg->msg_flags & MSG_DONTWAIT;
1001         long timeo = sock_sndtimeo(sk, nonblock);
1002         struct rds_conn_path *cpath;
1003
1004         /* Mirror Linux UDP mirror of BSD error message compatibility */
1005         /* XXX: Perhaps MSG_MORE someday */
1006         if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) {
1007                 ret = -EOPNOTSUPP;
1008                 goto out;
1009         }
1010
1011         if (msg->msg_namelen) {
1012                 /* XXX fail non-unicast destination IPs? */
1013                 if (msg->msg_namelen < sizeof(*usin) || usin->sin_family != AF_INET) {
1014                         ret = -EINVAL;
1015                         goto out;
1016                 }
1017                 daddr = usin->sin_addr.s_addr;
1018                 dport = usin->sin_port;
1019         } else {
1020                 /* We only care about consistency with ->connect() */
1021                 lock_sock(sk);
1022                 daddr = rs->rs_conn_addr;
1023                 dport = rs->rs_conn_port;
1024                 release_sock(sk);
1025         }
1026
1027         lock_sock(sk);
1028         if (daddr == 0 || rs->rs_bound_addr == 0) {
1029                 release_sock(sk);
1030                 ret = -ENOTCONN; /* XXX not a great errno */
1031                 goto out;
1032         }
1033         release_sock(sk);
1034
1035         if (payload_len > rds_sk_sndbuf(rs)) {
1036                 ret = -EMSGSIZE;
1037                 goto out;
1038         }
1039
1040         /* size of rm including all sgs */
1041         ret = rds_rm_size(msg, payload_len);
1042         if (ret < 0)
1043                 goto out;
1044
1045         rm = rds_message_alloc(ret, GFP_KERNEL);
1046         if (!rm) {
1047                 ret = -ENOMEM;
1048                 goto out;
1049         }
1050
1051         /* Attach data to the rm */
1052         if (payload_len) {
1053                 rm->data.op_sg = rds_message_alloc_sgs(rm, ceil(payload_len, PAGE_SIZE));
1054                 if (!rm->data.op_sg) {
1055                         ret = -ENOMEM;
1056                         goto out;
1057                 }
1058                 ret = rds_message_copy_from_user(rm, &msg->msg_iter);
1059                 if (ret)
1060                         goto out;
1061         }
1062         rm->data.op_active = 1;
1063
1064         rm->m_daddr = daddr;
1065
1066         /* rds_conn_create has a spinlock that runs with IRQ off.
1067          * Caching the conn in the socket helps a lot. */
1068         if (rs->rs_conn && rs->rs_conn->c_faddr == daddr)
1069                 conn = rs->rs_conn;
1070         else {
1071                 conn = rds_conn_create_outgoing(sock_net(sock->sk),
1072                                                 rs->rs_bound_addr, daddr,
1073                                         rs->rs_transport,
1074                                         sock->sk->sk_allocation);
1075                 if (IS_ERR(conn)) {
1076                         ret = PTR_ERR(conn);
1077                         goto out;
1078                 }
1079                 rs->rs_conn = conn;
1080         }
1081
1082         /* Parse any control messages the user may have included. */
1083         ret = rds_cmsg_send(rs, rm, msg, &allocated_mr);
1084         if (ret)
1085                 goto out;
1086
1087         if (rm->rdma.op_active && !conn->c_trans->xmit_rdma) {
1088                 printk_ratelimited(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",
1089                                &rm->rdma, conn->c_trans->xmit_rdma);
1090                 ret = -EOPNOTSUPP;
1091                 goto out;
1092         }
1093
1094         if (rm->atomic.op_active && !conn->c_trans->xmit_atomic) {
1095                 printk_ratelimited(KERN_NOTICE "atomic_op %p conn xmit_atomic %p\n",
1096                                &rm->atomic, conn->c_trans->xmit_atomic);
1097                 ret = -EOPNOTSUPP;
1098                 goto out;
1099         }
1100
1101         if (conn->c_trans->t_mp_capable)
1102                 cpath = &conn->c_path[rds_send_mprds_hash(rs, conn)];
1103         else
1104                 cpath = &conn->c_path[0];
1105
1106         rds_conn_path_connect_if_down(cpath);
1107
1108         ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);
1109         if (ret) {
1110                 rs->rs_seen_congestion = 1;
1111                 goto out;
1112         }
1113         while (!rds_send_queue_rm(rs, conn, cpath, rm, rs->rs_bound_port,
1114                                   dport, &queued)) {
1115                 rds_stats_inc(s_send_queue_full);
1116
1117                 if (nonblock) {
1118                         ret = -EAGAIN;
1119                         goto out;
1120                 }
1121
1122                 timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
1123                                         rds_send_queue_rm(rs, conn, cpath, rm,
1124                                                           rs->rs_bound_port,
1125                                                           dport,
1126                                                           &queued),
1127                                         timeo);
1128                 rdsdebug("sendmsg woke queued %d timeo %ld\n", queued, timeo);
1129                 if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
1130                         continue;
1131
1132                 ret = timeo;
1133                 if (ret == 0)
1134                         ret = -ETIMEDOUT;
1135                 goto out;
1136         }
1137
1138         /*
1139          * By now we've committed to the send.  We reuse rds_send_worker()
1140          * to retry sends in the rds thread if the transport asks us to.
1141          */
1142         rds_stats_inc(s_send_queued);
1143
1144         ret = rds_send_xmit(cpath);
1145         if (ret == -ENOMEM || ret == -EAGAIN)
1146                 queue_delayed_work(rds_wq, &cpath->cp_send_w, 1);
1147
1148         rds_message_put(rm);
1149         return payload_len;
1150
1151 out:
1152         /* If the user included a RDMA_MAP cmsg, we allocated a MR on the fly.
1153          * If the sendmsg goes through, we keep the MR. If it fails with EAGAIN
1154          * or in any other way, we need to destroy the MR again */
1155         if (allocated_mr)
1156                 rds_rdma_unuse(rs, rds_rdma_cookie_key(rm->m_rdma_cookie), 1);
1157
1158         if (rm)
1159                 rds_message_put(rm);
1160         return ret;
1161 }
1162
1163 /*
1164  * send out a probe. Can be shared by rds_send_ping,
1165  * rds_send_pong, rds_send_hb.
1166  * rds_send_hb should use h_flags
1167  *   RDS_FLAG_HB_PING|RDS_FLAG_ACK_REQUIRED
1168  * or
1169  *   RDS_FLAG_HB_PONG|RDS_FLAG_ACK_REQUIRED
1170  */
1171 int
1172 rds_send_probe(struct rds_conn_path *cp, __be16 sport,
1173                __be16 dport, u8 h_flags)
1174 {
1175         struct rds_message *rm;
1176         unsigned long flags;
1177         int ret = 0;
1178
1179         rm = rds_message_alloc(0, GFP_ATOMIC);
1180         if (!rm) {
1181                 ret = -ENOMEM;
1182                 goto out;
1183         }
1184
1185         rm->m_daddr = cp->cp_conn->c_faddr;
1186         rm->data.op_active = 1;
1187
1188         rds_conn_path_connect_if_down(cp);
1189
1190         ret = rds_cong_wait(cp->cp_conn->c_fcong, dport, 1, NULL);
1191         if (ret)
1192                 goto out;
1193
1194         spin_lock_irqsave(&cp->cp_lock, flags);
1195         list_add_tail(&rm->m_conn_item, &cp->cp_send_queue);
1196         set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
1197         rds_message_addref(rm);
1198         rm->m_inc.i_conn = cp->cp_conn;
1199         rm->m_inc.i_conn_path = cp;
1200
1201         rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport,
1202                                     cp->cp_next_tx_seq);
1203         rm->m_inc.i_hdr.h_flags |= h_flags;
1204         cp->cp_next_tx_seq++;
1205
1206         if (RDS_HS_PROBE(sport, dport) && cp->cp_conn->c_trans->t_mp_capable) {
1207                 u16 npaths = RDS_MPATH_WORKERS;
1208
1209                 rds_message_add_extension(&rm->m_inc.i_hdr,
1210                                           RDS_EXTHDR_NPATHS, &npaths,
1211                                           sizeof(npaths));
1212         }
1213         spin_unlock_irqrestore(&cp->cp_lock, flags);
1214
1215         rds_stats_inc(s_send_queued);
1216         rds_stats_inc(s_send_pong);
1217
1218         /* schedule the send work on rds_wq */
1219         queue_delayed_work(rds_wq, &cp->cp_send_w, 1);
1220
1221         rds_message_put(rm);
1222         return 0;
1223
1224 out:
1225         if (rm)
1226                 rds_message_put(rm);
1227         return ret;
1228 }
1229
1230 int
1231 rds_send_pong(struct rds_conn_path *cp, __be16 dport)
1232 {
1233         return rds_send_probe(cp, 0, dport, 0);
1234 }
1235
1236 void
1237 rds_send_ping(struct rds_connection *conn)
1238 {
1239         unsigned long flags;
1240         struct rds_conn_path *cp = &conn->c_path[0];
1241
1242         spin_lock_irqsave(&cp->cp_lock, flags);
1243         if (conn->c_ping_triggered) {
1244                 spin_unlock_irqrestore(&cp->cp_lock, flags);
1245                 return;
1246         }
1247         conn->c_ping_triggered = 1;
1248         spin_unlock_irqrestore(&cp->cp_lock, flags);
1249         rds_send_probe(&conn->c_path[0], RDS_FLAG_PROBE_PORT, 0, 0);
1250 }