net/rds/send.c

   1 /*
   2  * Copyright (c) 2006, 2018 Oracle and/or its affiliates. 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         unsigned int notify = 0;
 479
 480         spin_lock_irqsave(&rm->m_rs_lock, flags);
 481
 482         notify =  rm->rdma.op_notify | rm->data.op_notify;
 483         ro = &rm->rdma;
 484         if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) &&
 485             ro->op_active && notify && ro->op_notifier) {
 486                 notifier = ro->op_notifier;
 487                 rs = rm->m_rs;
 488                 sock_hold(rds_rs_to_sk(rs));
 489
 490                 notifier->n_status = status;
 491                 spin_lock(&rs->rs_lock);
 492                 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
 493                 spin_unlock(&rs->rs_lock);
 494
 495                 ro->op_notifier = NULL;
 496         }
 497
 498         spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 499
 500         if (rs) {
 501                 rds_wake_sk_sleep(rs);
 502                 sock_put(rds_rs_to_sk(rs));
 503         }
 504 }
 505 EXPORT_SYMBOL_GPL(rds_rdma_send_complete);
 506
 507 /*
 508  * Just like above, except looks at atomic op
 509  */
 510 void rds_atomic_send_complete(struct rds_message *rm, int status)
 511 {
 512         struct rds_sock *rs = NULL;
 513         struct rm_atomic_op *ao;
 514         struct rds_notifier *notifier;
 515         unsigned long flags;
 516
 517         spin_lock_irqsave(&rm->m_rs_lock, flags);
 518
 519         ao = &rm->atomic;
 520         if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags)
 521             && ao->op_active && ao->op_notify && ao->op_notifier) {
 522                 notifier = ao->op_notifier;
 523                 rs = rm->m_rs;
 524                 sock_hold(rds_rs_to_sk(rs));
 525
 526                 notifier->n_status = status;
 527                 spin_lock(&rs->rs_lock);
 528                 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
 529                 spin_unlock(&rs->rs_lock);
 530
 531                 ao->op_notifier = NULL;
 532         }
 533
 534         spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 535
 536         if (rs) {
 537                 rds_wake_sk_sleep(rs);
 538                 sock_put(rds_rs_to_sk(rs));
 539         }
 540 }
 541 EXPORT_SYMBOL_GPL(rds_atomic_send_complete);
 542
 543 /*
 544  * This is the same as rds_rdma_send_complete except we
 545  * don't do any locking - we have all the ingredients (message,
 546  * socket, socket lock) and can just move the notifier.
 547  */
 548 static inline void
 549 __rds_send_complete(struct rds_sock *rs, struct rds_message *rm, int status)
 550 {
 551         struct rm_rdma_op *ro;
 552         struct rm_atomic_op *ao;
 553
 554         ro = &rm->rdma;
 555         if (ro->op_active && ro->op_notify && ro->op_notifier) {
 556                 ro->op_notifier->n_status = status;
 557                 list_add_tail(&ro->op_notifier->n_list, &rs->rs_notify_queue);
 558                 ro->op_notifier = NULL;
 559         }
 560
 561         ao = &rm->atomic;
 562         if (ao->op_active && ao->op_notify && ao->op_notifier) {
 563                 ao->op_notifier->n_status = status;
 564                 list_add_tail(&ao->op_notifier->n_list, &rs->rs_notify_queue);
 565                 ao->op_notifier = NULL;
 566         }
 567
 568         /* No need to wake the app - caller does this */
 569 }
 570
 571 /*
 572  * This removes messages from the socket's list if they're on it.  The list
 573  * argument must be private to the caller, we must be able to modify it
 574  * without locks.  The messages must have a reference held for their
 575  * position on the list.  This function will drop that reference after
 576  * removing the messages from the 'messages' list regardless of if it found
 577  * the messages on the socket list or not.
 578  */
 579 static void rds_send_remove_from_sock(struct list_head *messages, int status)
 580 {
 581         unsigned long flags;
 582         struct rds_sock *rs = NULL;
 583         struct rds_message *rm;
 584
 585         while (!list_empty(messages)) {
 586                 int was_on_sock = 0;
 587
 588                 rm = list_entry(messages->next, struct rds_message,
 589                                 m_conn_item);
 590                 list_del_init(&rm->m_conn_item);
 591
 592                 /*
 593                  * If we see this flag cleared then we're *sure* that someone
 594                  * else beat us to removing it from the sock.  If we race
 595                  * with their flag update we'll get the lock and then really
 596                  * see that the flag has been cleared.
 597                  *
 598                  * The message spinlock makes sure nobody clears rm->m_rs
 599                  * while we're messing with it. It does not prevent the
 600                  * message from being removed from the socket, though.
 601                  */
 602                 spin_lock_irqsave(&rm->m_rs_lock, flags);
 603                 if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags))
 604                         goto unlock_and_drop;
 605
 606                 if (rs != rm->m_rs) {
 607                         if (rs) {
 608                                 rds_wake_sk_sleep(rs);
 609                                 sock_put(rds_rs_to_sk(rs));
 610                         }
 611                         rs = rm->m_rs;
 612                         if (rs)
 613                                 sock_hold(rds_rs_to_sk(rs));
 614                 }
 615                 if (!rs)
 616                         goto unlock_and_drop;
 617                 spin_lock(&rs->rs_lock);
 618
 619                 if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) {
 620                         struct rm_rdma_op *ro = &rm->rdma;
 621                         struct rds_notifier *notifier;
 622
 623                         list_del_init(&rm->m_sock_item);
 624                         rds_send_sndbuf_remove(rs, rm);
 625
 626                         if (ro->op_active && ro->op_notifier &&
 627                                (ro->op_notify || (ro->op_recverr && status))) {
 628                                 notifier = ro->op_notifier;
 629                                 list_add_tail(&notifier->n_list,
 630                                                 &rs->rs_notify_queue);
 631                                 if (!notifier->n_status)
 632                                         notifier->n_status = status;
 633                                 rm->rdma.op_notifier = NULL;
 634                         }
 635                         was_on_sock = 1;
 636                         rm->m_rs = NULL;
 637                 }
 638                 spin_unlock(&rs->rs_lock);
 639
 640 unlock_and_drop:
 641                 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 642                 rds_message_put(rm);
 643                 if (was_on_sock)
 644                         rds_message_put(rm);
 645         }
 646
 647         if (rs) {
 648                 rds_wake_sk_sleep(rs);
 649                 sock_put(rds_rs_to_sk(rs));
 650         }
 651 }
 652
 653 /*
 654  * Transports call here when they've determined that the receiver queued
 655  * messages up to, and including, the given sequence number.  Messages are
 656  * moved to the retrans queue when rds_send_xmit picks them off the send
 657  * queue. This means that in the TCP case, the message may not have been
 658  * assigned the m_ack_seq yet - but that's fine as long as tcp_is_acked
 659  * checks the RDS_MSG_HAS_ACK_SEQ bit.
 660  */
 661 void rds_send_path_drop_acked(struct rds_conn_path *cp, u64 ack,
 662                               is_acked_func is_acked)
 663 {
 664         struct rds_message *rm, *tmp;
 665         unsigned long flags;
 666         LIST_HEAD(list);
 667
 668         spin_lock_irqsave(&cp->cp_lock, flags);
 669
 670         list_for_each_entry_safe(rm, tmp, &cp->cp_retrans, m_conn_item) {
 671                 if (!rds_send_is_acked(rm, ack, is_acked))
 672                         break;
 673
 674                 list_move(&rm->m_conn_item, &list);
 675                 clear_bit(RDS_MSG_ON_CONN, &rm->m_flags);
 676         }
 677
 678         /* order flag updates with spin locks */
 679         if (!list_empty(&list))
 680                 smp_mb__after_atomic();
 681
 682         spin_unlock_irqrestore(&cp->cp_lock, flags);
 683
 684         /* now remove the messages from the sock list as needed */
 685         rds_send_remove_from_sock(&list, RDS_RDMA_SUCCESS);
 686 }
 687 EXPORT_SYMBOL_GPL(rds_send_path_drop_acked);
 688
 689 void rds_send_drop_acked(struct rds_connection *conn, u64 ack,
 690                          is_acked_func is_acked)
 691 {
 692         WARN_ON(conn->c_trans->t_mp_capable);
 693         rds_send_path_drop_acked(&conn->c_path[0], ack, is_acked);
 694 }
 695 EXPORT_SYMBOL_GPL(rds_send_drop_acked);
 696
 697 void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest)
 698 {
 699         struct rds_message *rm, *tmp;
 700         struct rds_connection *conn;
 701         struct rds_conn_path *cp;
 702         unsigned long flags;
 703         LIST_HEAD(list);
 704
 705         /* get all the messages we're dropping under the rs lock */
 706         spin_lock_irqsave(&rs->rs_lock, flags);
 707
 708         list_for_each_entry_safe(rm, tmp, &rs->rs_send_queue, m_sock_item) {
 709                 if (dest && (dest->sin_addr.s_addr != rm->m_daddr ||
 710                              dest->sin_port != rm->m_inc.i_hdr.h_dport))
 711                         continue;
 712
 713                 list_move(&rm->m_sock_item, &list);
 714                 rds_send_sndbuf_remove(rs, rm);
 715                 clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
 716         }
 717
 718         /* order flag updates with the rs lock */
 719         smp_mb__after_atomic();
 720
 721         spin_unlock_irqrestore(&rs->rs_lock, flags);
 722
 723         if (list_empty(&list))
 724                 return;
 725
 726         /* Remove the messages from the conn */
 727         list_for_each_entry(rm, &list, m_sock_item) {
 728
 729                 conn = rm->m_inc.i_conn;
 730                 if (conn->c_trans->t_mp_capable)
 731                         cp = rm->m_inc.i_conn_path;
 732                 else
 733                         cp = &conn->c_path[0];
 734
 735                 spin_lock_irqsave(&cp->cp_lock, flags);
 736                 /*
 737                  * Maybe someone else beat us to removing rm from the conn.
 738                  * If we race with their flag update we'll get the lock and
 739                  * then really see that the flag has been cleared.
 740                  */
 741                 if (!test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) {
 742                         spin_unlock_irqrestore(&cp->cp_lock, flags);
 743                         spin_lock_irqsave(&rm->m_rs_lock, flags);
 744                         rm->m_rs = NULL;
 745                         spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 746                         continue;
 747                 }
 748                 list_del_init(&rm->m_conn_item);
 749                 spin_unlock_irqrestore(&cp->cp_lock, flags);
 750
 751                 /*
 752                  * Couldn't grab m_rs_lock in top loop (lock ordering),
 753                  * but we can now.
 754                  */
 755                 spin_lock_irqsave(&rm->m_rs_lock, flags);
 756
 757                 spin_lock(&rs->rs_lock);
 758                 __rds_send_complete(rs, rm, RDS_RDMA_CANCELED);
 759                 spin_unlock(&rs->rs_lock);
 760
 761                 rm->m_rs = NULL;
 762                 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 763
 764                 rds_message_put(rm);
 765         }
 766
 767         rds_wake_sk_sleep(rs);
 768
 769         while (!list_empty(&list)) {
 770                 rm = list_entry(list.next, struct rds_message, m_sock_item);
 771                 list_del_init(&rm->m_sock_item);
 772                 rds_message_wait(rm);
 773
 774                 /* just in case the code above skipped this message
 775                  * because RDS_MSG_ON_CONN wasn't set, run it again here
 776                  * taking m_rs_lock is the only thing that keeps us
 777                  * from racing with ack processing.
 778                  */
 779                 spin_lock_irqsave(&rm->m_rs_lock, flags);
 780
 781                 spin_lock(&rs->rs_lock);
 782                 __rds_send_complete(rs, rm, RDS_RDMA_CANCELED);
 783                 spin_unlock(&rs->rs_lock);
 784
 785                 rm->m_rs = NULL;
 786                 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 787
 788                 rds_message_put(rm);
 789         }
 790 }
 791
 792 /*
 793  * we only want this to fire once so we use the callers 'queued'.  It's
 794  * possible that another thread can race with us and remove the
 795  * message from the flow with RDS_CANCEL_SENT_TO.
 796  */
 797 static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn,
 798                              struct rds_conn_path *cp,
 799                              struct rds_message *rm, __be16 sport,
 800                              __be16 dport, int *queued)
 801 {
 802         unsigned long flags;
 803         u32 len;
 804
 805         if (*queued)
 806                 goto out;
 807
 808         len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
 809
 810         /* this is the only place which holds both the socket's rs_lock
 811          * and the connection's c_lock */
 812         spin_lock_irqsave(&rs->rs_lock, flags);
 813
 814         /*
 815          * If there is a little space in sndbuf, we don't queue anything,
 816          * and userspace gets -EAGAIN. But poll() indicates there's send
 817          * room. This can lead to bad behavior (spinning) if snd_bytes isn't
 818          * freed up by incoming acks. So we check the *old* value of
 819          * rs_snd_bytes here to allow the last msg to exceed the buffer,
 820          * and poll() now knows no more data can be sent.
 821          */
 822         if (rs->rs_snd_bytes < rds_sk_sndbuf(rs)) {
 823                 rs->rs_snd_bytes += len;
 824
 825                 /* let recv side know we are close to send space exhaustion.
 826                  * This is probably not the optimal way to do it, as this
 827                  * means we set the flag on *all* messages as soon as our
 828                  * throughput hits a certain threshold.
 829                  */
 830                 if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2)
 831                         __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
 832
 833                 list_add_tail(&rm->m_sock_item, &rs->rs_send_queue);
 834                 set_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
 835                 rds_message_addref(rm);
 836                 rm->m_rs = rs;
 837
 838                 /* The code ordering is a little weird, but we're
 839                    trying to minimize the time we hold c_lock */
 840                 rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport, 0);
 841                 rm->m_inc.i_conn = conn;
 842                 rm->m_inc.i_conn_path = cp;
 843                 rds_message_addref(rm);
 844
 845                 spin_lock(&cp->cp_lock);
 846                 rm->m_inc.i_hdr.h_sequence = cpu_to_be64(cp->cp_next_tx_seq++);
 847                 list_add_tail(&rm->m_conn_item, &cp->cp_send_queue);
 848                 set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
 849                 spin_unlock(&cp->cp_lock);
 850
 851                 rdsdebug("queued msg %p len %d, rs %p bytes %d seq %llu\n",
 852                          rm, len, rs, rs->rs_snd_bytes,
 853                          (unsigned long long)be64_to_cpu(rm->m_inc.i_hdr.h_sequence));
 854
 855                 *queued = 1;
 856         }
 857
 858         spin_unlock_irqrestore(&rs->rs_lock, flags);
 859 out:
 860         return *queued;
 861 }
 862
 863 /*
 864  * rds_message is getting to be quite complicated, and we'd like to allocate
 865  * it all in one go. This figures out how big it needs to be up front.
 866  */
 867 static int rds_rm_size(struct msghdr *msg, int data_len)
 868 {
 869         struct cmsghdr *cmsg;
 870         int size = 0;
 871         int cmsg_groups = 0;
 872         int retval;
 873
 874         for_each_cmsghdr(cmsg, msg) {
 875                 if (!CMSG_OK(msg, cmsg))
 876                         return -EINVAL;
 877
 878                 if (cmsg->cmsg_level != SOL_RDS)
 879                         continue;
 880
 881                 switch (cmsg->cmsg_type) {
 882                 case RDS_CMSG_RDMA_ARGS:
 883                         cmsg_groups |= 1;
 884                         retval = rds_rdma_extra_size(CMSG_DATA(cmsg));
 885                         if (retval < 0)
 886                                 return retval;
 887                         size += retval;
 888
 889                         break;
 890
 891                 case RDS_CMSG_RDMA_DEST:
 892                 case RDS_CMSG_RDMA_MAP:
 893                         cmsg_groups |= 2;
 894                         /* these are valid but do no add any size */
 895                         break;
 896
 897                 case RDS_CMSG_ATOMIC_CSWP:
 898                 case RDS_CMSG_ATOMIC_FADD:
 899                 case RDS_CMSG_MASKED_ATOMIC_CSWP:
 900                 case RDS_CMSG_MASKED_ATOMIC_FADD:
 901                         cmsg_groups |= 1;
 902                         size += sizeof(struct scatterlist);
 903                         break;
 904
 905                 default:
 906                         return -EINVAL;
 907                 }
 908
 909         }
 910
 911         size += ceil(data_len, PAGE_SIZE) * sizeof(struct scatterlist);
 912
 913         /* Ensure (DEST, MAP) are never used with (ARGS, ATOMIC) */
 914         if (cmsg_groups == 3)
 915                 return -EINVAL;
 916
 917         return size;
 918 }
 919
 920 static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
 921                          struct msghdr *msg, int *allocated_mr)
 922 {
 923         struct cmsghdr *cmsg;
 924         int ret = 0;
 925
 926         for_each_cmsghdr(cmsg, msg) {
 927                 if (!CMSG_OK(msg, cmsg))
 928                         return -EINVAL;
 929
 930                 if (cmsg->cmsg_level != SOL_RDS)
 931                         continue;
 932
 933                 /* As a side effect, RDMA_DEST and RDMA_MAP will set
 934                  * rm->rdma.m_rdma_cookie and rm->rdma.m_rdma_mr.
 935                  */
 936                 switch (cmsg->cmsg_type) {
 937                 case RDS_CMSG_RDMA_ARGS:
 938                         ret = rds_cmsg_rdma_args(rs, rm, cmsg);
 939                         break;
 940
 941                 case RDS_CMSG_RDMA_DEST:
 942                         ret = rds_cmsg_rdma_dest(rs, rm, cmsg);
 943                         break;
 944
 945                 case RDS_CMSG_RDMA_MAP:
 946                         ret = rds_cmsg_rdma_map(rs, rm, cmsg);
 947                         if (!ret)
 948                                 *allocated_mr = 1;
 949                         else if (ret == -ENODEV)
 950                                 /* Accommodate the get_mr() case which can fail
 951                                  * if connection isn't established yet.
 952                                  */
 953                                 ret = -EAGAIN;
 954                         break;
 955                 case RDS_CMSG_ATOMIC_CSWP:
 956                 case RDS_CMSG_ATOMIC_FADD:
 957                 case RDS_CMSG_MASKED_ATOMIC_CSWP:
 958                 case RDS_CMSG_MASKED_ATOMIC_FADD:
 959                         ret = rds_cmsg_atomic(rs, rm, cmsg);
 960                         break;
 961
 962                 default:
 963                         return -EINVAL;
 964                 }
 965
 966                 if (ret)
 967                         break;
 968         }
 969
 970         return ret;
 971 }
 972
 973 static void rds_send_ping(struct rds_connection *conn);
 974
 975 static int rds_send_mprds_hash(struct rds_sock *rs, struct rds_connection *conn)
 976 {
 977         int hash;
 978
 979         if (conn->c_npaths == 0)
 980                 hash = RDS_MPATH_HASH(rs, RDS_MPATH_WORKERS);
 981         else
 982                 hash = RDS_MPATH_HASH(rs, conn->c_npaths);
 983         if (conn->c_npaths == 0 && hash != 0) {
 984                 rds_send_ping(conn);
 985
 986                 /* The underlying connection is not up yet.  Need to wait
 987                  * until it is up to be sure that the non-zero c_path can be
 988                  * used.  But if we are interrupted, we have to use the zero
 989                  * c_path in case the connection ends up being non-MP capable.
 990                  */
 991                 if (conn->c_npaths == 0)
 992                         if (wait_event_interruptible(conn->c_hs_waitq,
 993                                                      conn->c_npaths != 0))
 994                                 hash = 0;
 995                 if (conn->c_npaths == 1)
 996                         hash = 0;
 997         }
 998         return hash;
 999 }
1000
1001 static int rds_rdma_bytes(struct msghdr *msg, size_t *rdma_bytes)
1002 {
1003         struct rds_rdma_args *args;
1004         struct cmsghdr *cmsg;
1005
1006         for_each_cmsghdr(cmsg, msg) {
1007                 if (!CMSG_OK(msg, cmsg))
1008                         return -EINVAL;
1009
1010                 if (cmsg->cmsg_level != SOL_RDS)
1011                         continue;
1012
1013                 if (cmsg->cmsg_type == RDS_CMSG_RDMA_ARGS) {
1014                         if (cmsg->cmsg_len <
1015                             CMSG_LEN(sizeof(struct rds_rdma_args)))
1016                                 return -EINVAL;
1017                         args = CMSG_DATA(cmsg);
1018                         *rdma_bytes += args->remote_vec.bytes;
1019                 }
1020         }
1021         return 0;
1022 }
1023
1024 int rds_sendmsg(struct socket *sock, struct msghdr *msg, size_t payload_len)
1025 {
1026         struct sock *sk = sock->sk;
1027         struct rds_sock *rs = rds_sk_to_rs(sk);
1028         DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
1029         __be32 daddr;
1030         __be16 dport;
1031         struct rds_message *rm = NULL;
1032         struct rds_connection *conn;
1033         int ret = 0;
1034         int queued = 0, allocated_mr = 0;
1035         int nonblock = msg->msg_flags & MSG_DONTWAIT;
1036         long timeo = sock_sndtimeo(sk, nonblock);
1037         struct rds_conn_path *cpath;
1038         size_t total_payload_len = payload_len, rdma_payload_len = 0;
1039
1040         /* Mirror Linux UDP mirror of BSD error message compatibility */
1041         /* XXX: Perhaps MSG_MORE someday */
1042         if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) {
1043                 ret = -EOPNOTSUPP;
1044                 goto out;
1045         }
1046
1047         if (msg->msg_namelen) {
1048                 /* XXX fail non-unicast destination IPs? */
1049                 if (msg->msg_namelen < sizeof(*usin) || usin->sin_family != AF_INET) {
1050                         ret = -EINVAL;
1051                         goto out;
1052                 }
1053                 daddr = usin->sin_addr.s_addr;
1054                 dport = usin->sin_port;
1055         } else {
1056                 /* We only care about consistency with ->connect() */
1057                 lock_sock(sk);
1058                 daddr = rs->rs_conn_addr;
1059                 dport = rs->rs_conn_port;
1060                 release_sock(sk);
1061         }
1062
1063         lock_sock(sk);
1064         if (daddr == 0 || rs->rs_bound_addr == 0) {
1065                 release_sock(sk);
1066                 ret = -ENOTCONN; /* XXX not a great errno */
1067                 goto out;
1068         }
1069         release_sock(sk);
1070
1071         ret = rds_rdma_bytes(msg, &rdma_payload_len);
1072         if (ret)
1073                 goto out;
1074
1075         total_payload_len += rdma_payload_len;
1076         if (max_t(size_t, payload_len, rdma_payload_len) > RDS_MAX_MSG_SIZE) {
1077                 ret = -EMSGSIZE;
1078                 goto out;
1079         }
1080
1081         if (payload_len > rds_sk_sndbuf(rs)) {
1082                 ret = -EMSGSIZE;
1083                 goto out;
1084         }
1085
1086         /* size of rm including all sgs */
1087         ret = rds_rm_size(msg, payload_len);
1088         if (ret < 0)
1089                 goto out;
1090
1091         rm = rds_message_alloc(ret, GFP_KERNEL);
1092         if (!rm) {
1093                 ret = -ENOMEM;
1094                 goto out;
1095         }
1096
1097         /* Attach data to the rm */
1098         if (payload_len) {
1099                 rm->data.op_sg = rds_message_alloc_sgs(rm, ceil(payload_len, PAGE_SIZE));
1100                 if (!rm->data.op_sg) {
1101                         ret = -ENOMEM;
1102                         goto out;
1103                 }
1104                 ret = rds_message_copy_from_user(rm, &msg->msg_iter);
1105                 if (ret)
1106                         goto out;
1107         }
1108         rm->data.op_active = 1;
1109
1110         rm->m_daddr = daddr;
1111
1112         /* rds_conn_create has a spinlock that runs with IRQ off.
1113          * Caching the conn in the socket helps a lot. */
1114         if (rs->rs_conn && rs->rs_conn->c_faddr == daddr)
1115                 conn = rs->rs_conn;
1116         else {
1117                 conn = rds_conn_create_outgoing(sock_net(sock->sk),
1118                                                 rs->rs_bound_addr, daddr,
1119                                         rs->rs_transport,
1120                                         sock->sk->sk_allocation);
1121                 if (IS_ERR(conn)) {
1122                         ret = PTR_ERR(conn);
1123                         goto out;
1124                 }
1125                 rs->rs_conn = conn;
1126         }
1127
1128         /* Parse any control messages the user may have included. */
1129         ret = rds_cmsg_send(rs, rm, msg, &allocated_mr);
1130         if (ret) {
1131                 /* Trigger connection so that its ready for the next retry */
1132                 if (ret ==  -EAGAIN)
1133                         rds_conn_connect_if_down(conn);
1134                 goto out;
1135         }
1136
1137         if (rm->rdma.op_active && !conn->c_trans->xmit_rdma) {
1138                 printk_ratelimited(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",
1139                                &rm->rdma, conn->c_trans->xmit_rdma);
1140                 ret = -EOPNOTSUPP;
1141                 goto out;
1142         }
1143
1144         if (rm->atomic.op_active && !conn->c_trans->xmit_atomic) {
1145                 printk_ratelimited(KERN_NOTICE "atomic_op %p conn xmit_atomic %p\n",
1146                                &rm->atomic, conn->c_trans->xmit_atomic);
1147                 ret = -EOPNOTSUPP;
1148                 goto out;
1149         }
1150
1151         if (conn->c_trans->t_mp_capable)
1152                 cpath = &conn->c_path[rds_send_mprds_hash(rs, conn)];
1153         else
1154                 cpath = &conn->c_path[0];
1155
1156         rds_conn_path_connect_if_down(cpath);
1157
1158         ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);
1159         if (ret) {
1160                 rs->rs_seen_congestion = 1;
1161                 goto out;
1162         }
1163         while (!rds_send_queue_rm(rs, conn, cpath, rm, rs->rs_bound_port,
1164                                   dport, &queued)) {
1165                 rds_stats_inc(s_send_queue_full);
1166
1167                 if (nonblock) {
1168                         ret = -EAGAIN;
1169                         goto out;
1170                 }
1171
1172                 timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
1173                                         rds_send_queue_rm(rs, conn, cpath, rm,
1174                                                           rs->rs_bound_port,
1175                                                           dport,
1176                                                           &queued),
1177                                         timeo);
1178                 rdsdebug("sendmsg woke queued %d timeo %ld\n", queued, timeo);
1179                 if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
1180                         continue;
1181
1182                 ret = timeo;
1183                 if (ret == 0)
1184                         ret = -ETIMEDOUT;
1185                 goto out;
1186         }
1187
1188         /*
1189          * By now we've committed to the send.  We reuse rds_send_worker()
1190          * to retry sends in the rds thread if the transport asks us to.
1191          */
1192         rds_stats_inc(s_send_queued);
1193
1194         ret = rds_send_xmit(cpath);
1195         if (ret == -ENOMEM || ret == -EAGAIN)
1196                 queue_delayed_work(rds_wq, &cpath->cp_send_w, 1);
1197
1198         rds_message_put(rm);
1199         return payload_len;
1200
1201 out:
1202         /* If the user included a RDMA_MAP cmsg, we allocated a MR on the fly.
1203          * If the sendmsg goes through, we keep the MR. If it fails with EAGAIN
1204          * or in any other way, we need to destroy the MR again */
1205         if (allocated_mr)
1206                 rds_rdma_unuse(rs, rds_rdma_cookie_key(rm->m_rdma_cookie), 1);
1207
1208         if (rm)
1209                 rds_message_put(rm);
1210         return ret;
1211 }
1212
1213 /*
1214  * send out a probe. Can be shared by rds_send_ping,
1215  * rds_send_pong, rds_send_hb.
1216  * rds_send_hb should use h_flags
1217  *   RDS_FLAG_HB_PING|RDS_FLAG_ACK_REQUIRED
1218  * or
1219  *   RDS_FLAG_HB_PONG|RDS_FLAG_ACK_REQUIRED
1220  */
1221 int
1222 rds_send_probe(struct rds_conn_path *cp, __be16 sport,
1223                __be16 dport, u8 h_flags)
1224 {
1225         struct rds_message *rm;
1226         unsigned long flags;
1227         int ret = 0;
1228
1229         rm = rds_message_alloc(0, GFP_ATOMIC);
1230         if (!rm) {
1231                 ret = -ENOMEM;
1232                 goto out;
1233         }
1234
1235         rm->m_daddr = cp->cp_conn->c_faddr;
1236         rm->data.op_active = 1;
1237
1238         rds_conn_path_connect_if_down(cp);
1239
1240         ret = rds_cong_wait(cp->cp_conn->c_fcong, dport, 1, NULL);
1241         if (ret)
1242                 goto out;
1243
1244         spin_lock_irqsave(&cp->cp_lock, flags);
1245         list_add_tail(&rm->m_conn_item, &cp->cp_send_queue);
1246         set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
1247         rds_message_addref(rm);
1248         rm->m_inc.i_conn = cp->cp_conn;
1249         rm->m_inc.i_conn_path = cp;
1250
1251         rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport,
1252                                     cp->cp_next_tx_seq);
1253         rm->m_inc.i_hdr.h_flags |= h_flags;
1254         cp->cp_next_tx_seq++;
1255
1256         if (RDS_HS_PROBE(sport, dport) && cp->cp_conn->c_trans->t_mp_capable) {
1257                 u16 npaths = RDS_MPATH_WORKERS;
1258
1259                 rds_message_add_extension(&rm->m_inc.i_hdr,
1260                                           RDS_EXTHDR_NPATHS, &npaths,
1261                                           sizeof(npaths));
1262         }
1263         spin_unlock_irqrestore(&cp->cp_lock, flags);
1264
1265         rds_stats_inc(s_send_queued);
1266         rds_stats_inc(s_send_pong);
1267
1268         /* schedule the send work on rds_wq */
1269         queue_delayed_work(rds_wq, &cp->cp_send_w, 1);
1270
1271         rds_message_put(rm);
1272         return 0;
1273
1274 out:
1275         if (rm)
1276                 rds_message_put(rm);
1277         return ret;
1278 }
1279
1280 int
1281 rds_send_pong(struct rds_conn_path *cp, __be16 dport)
1282 {
1283         return rds_send_probe(cp, 0, dport, 0);
1284 }
1285
1286 void
1287 rds_send_ping(struct rds_connection *conn)
1288 {
1289         unsigned long flags;
1290         struct rds_conn_path *cp = &conn->c_path[0];
1291
1292         spin_lock_irqsave(&cp->cp_lock, flags);
1293         if (conn->c_ping_triggered) {
1294                 spin_unlock_irqrestore(&cp->cp_lock, flags);
1295                 return;
1296         }
1297         conn->c_ping_triggered = 1;
1298         spin_unlock_irqrestore(&cp->cp_lock, flags);
1299         rds_send_probe(&conn->c_path[0], RDS_FLAG_PROBE_PORT, 0, 0);
1300 }