net/rds/send.c

   1 /*
   2  * Copyright (c) 2006 Oracle.  All rights reserved.
   3  *
   4  * This software is available to you under a choice of one of two
   5  * licenses.  You may choose to be licensed under the terms of the GNU
   6  * General Public License (GPL) Version 2, available from the file
   7  * COPYING in the main directory of this source tree, or the
   8  * OpenIB.org BSD license below:
   9  *
  10  *     Redistribution and use in source and binary forms, with or
  11  *     without modification, are permitted provided that the following
  12  *     conditions are met:
  13  *
  14  *      - Redistributions of source code must retain the above
  15  *        copyright notice, this list of conditions and the following
  16  *        disclaimer.
  17  *
  18  *      - Redistributions in binary form must reproduce the above
  19  *        copyright notice, this list of conditions and the following
  20  *        disclaimer in the documentation and/or other materials
  21  *        provided with the distribution.
  22  *
  23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  30  * SOFTWARE.
  31  *
  32  */
  33 #include <linux/kernel.h>
  34 #include <linux/gfp.h>
  35 #include <net/sock.h>
  36 #include <linux/in.h>
  37 #include <linux/list.h>
  38
  39 #include "rds.h"
  40
  41 /* When transmitting messages in rds_send_xmit, we need to emerge from
  42  * time to time and briefly release the CPU. Otherwise the softlock watchdog
  43  * will kick our shin.
  44  * Also, it seems fairer to not let one busy connection stall all the
  45  * others.
  46  *
  47  * send_batch_count is the number of times we'll loop in send_xmit. Setting
  48  * it to 0 will restore the old behavior (where we looped until we had
  49  * drained the queue).
  50  */
  51 static int send_batch_count = 64;
  52 module_param(send_batch_count, int, 0444);
  53 MODULE_PARM_DESC(send_batch_count, " batch factor when working the send queue");
  54
  55 /*
  56  * Reset the send state.  Callers must ensure that this doesn't race with
  57  * rds_send_xmit().
  58  */
  59 void rds_send_reset(struct rds_connection *conn)
  60 {
  61         struct rds_message *rm, *tmp;
  62         unsigned long flags;
  63
  64         if (conn->c_xmit_rm) {
  65                 rm = conn->c_xmit_rm;
  66                 conn->c_xmit_rm = NULL;
  67                 /* Tell the user the RDMA op is no longer mapped by the
  68                  * transport. This isn't entirely true (it's flushed out
  69                  * independently) but as the connection is down, there's
  70                  * no ongoing RDMA to/from that memory */
  71                 rds_message_unmapped(rm);
  72                 rds_message_put(rm);
  73         }
  74
  75         conn->c_xmit_sg = 0;
  76         conn->c_xmit_hdr_off = 0;
  77         conn->c_xmit_data_off = 0;
  78         conn->c_xmit_atomic_sent = 0;
  79         conn->c_xmit_rdma_sent = 0;
  80         conn->c_xmit_data_sent = 0;
  81
  82         conn->c_map_queued = 0;
  83
  84         conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
  85         conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
  86
  87         /* Mark messages as retransmissions, and move them to the send q */
  88         spin_lock_irqsave(&conn->c_lock, flags);
  89         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
  90                 set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
  91                 set_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags);
  92         }
  93         list_splice_init(&conn->c_retrans, &conn->c_send_queue);
  94         spin_unlock_irqrestore(&conn->c_lock, flags);
  95 }
  96
  97 static int acquire_in_xmit(struct rds_connection *conn)
  98 {
  99         return test_and_set_bit(RDS_IN_XMIT, &conn->c_flags) == 0;
 100 }
 101
 102 static void release_in_xmit(struct rds_connection *conn)
 103 {
 104         clear_bit(RDS_IN_XMIT, &conn->c_flags);
 105         smp_mb__after_clear_bit();
 106         /*
 107          * We don't use wait_on_bit()/wake_up_bit() because our waking is in a
 108          * hot path and finding waiters is very rare.  We don't want to walk
 109          * the system-wide hashed waitqueue buckets in the fast path only to
 110          * almost never find waiters.
 111          */
 112         if (waitqueue_active(&conn->c_waitq))
 113                 wake_up_all(&conn->c_waitq);
 114 }
 115
 116 /*
 117  * We're making the concious trade-off here to only send one message
 118  * down the connection at a time.
 119  *   Pro:
 120  *      - tx queueing is a simple fifo list
 121  *      - reassembly is optional and easily done by transports per conn
 122  *      - no per flow rx lookup at all, straight to the socket
 123  *      - less per-frag memory and wire overhead
 124  *   Con:
 125  *      - queued acks can be delayed behind large messages
 126  *   Depends:
 127  *      - small message latency is higher behind queued large messages
 128  *      - large message latency isn't starved by intervening small sends
 129  */
 130 int rds_send_xmit(struct rds_connection *conn)
 131 {
 132         struct rds_message *rm;
 133         unsigned long flags;
 134         unsigned int tmp;
 135         struct scatterlist *sg;
 136         int ret = 0;
 137         LIST_HEAD(to_be_dropped);
 138
 139 restart:
 140
 141         /*
 142          * sendmsg calls here after having queued its message on the send
 143          * queue.  We only have one task feeding the connection at a time.  If
 144          * another thread is already feeding the queue then we back off.  This
 145          * avoids blocking the caller and trading per-connection data between
 146          * caches per message.
 147          */
 148         if (!acquire_in_xmit(conn)) {
 149                 rds_stats_inc(s_send_lock_contention);
 150                 ret = -ENOMEM;
 151                 goto out;
 152         }
 153
 154         /*
 155          * rds_conn_shutdown() sets the conn state and then tests RDS_IN_XMIT,
 156          * we do the opposite to avoid races.
 157          */
 158         if (!rds_conn_up(conn)) {
 159                 release_in_xmit(conn);
 160                 ret = 0;
 161                 goto out;
 162         }
 163
 164         if (conn->c_trans->xmit_prepare)
 165                 conn->c_trans->xmit_prepare(conn);
 166
 167         /*
 168          * spin trying to push headers and data down the connection until
 169          * the connection doesn't make forward progress.
 170          */
 171         while (1) {
 172
 173                 rm = conn->c_xmit_rm;
 174
 175                 /*
 176                  * If between sending messages, we can send a pending congestion
 177                  * map update.
 178                  */
 179                 if (!rm && test_and_clear_bit(0, &conn->c_map_queued)) {
 180                         rm = rds_cong_update_alloc(conn);
 181                         if (IS_ERR(rm)) {
 182                                 ret = PTR_ERR(rm);
 183                                 break;
 184                         }
 185                         rm->data.op_active = 1;
 186
 187                         conn->c_xmit_rm = rm;
 188                 }
 189
 190                 /*
 191                  * If not already working on one, grab the next message.
 192                  *
 193                  * c_xmit_rm holds a ref while we're sending this message down
 194                  * the connction.  We can use this ref while holding the
 195                  * send_sem.. rds_send_reset() is serialized with it.
 196                  */
 197                 if (!rm) {
 198                         unsigned int len;
 199
 200                         spin_lock_irqsave(&conn->c_lock, flags);
 201
 202                         if (!list_empty(&conn->c_send_queue)) {
 203                                 rm = list_entry(conn->c_send_queue.next,
 204                                                 struct rds_message,
 205                                                 m_conn_item);
 206                                 rds_message_addref(rm);
 207
 208                                 /*
 209                                  * Move the message from the send queue to the retransmit
 210                                  * list right away.
 211                                  */
 212                                 list_move_tail(&rm->m_conn_item, &conn->c_retrans);
 213                         }
 214
 215                         spin_unlock_irqrestore(&conn->c_lock, flags);
 216
 217                         if (!rm)
 218                                 break;
 219
 220                         /* Unfortunately, the way Infiniband deals with
 221                          * RDMA to a bad MR key is by moving the entire
 222                          * queue pair to error state. We cold possibly
 223                          * recover from that, but right now we drop the
 224                          * connection.
 225                          * Therefore, we never retransmit messages with RDMA ops.
 226                          */
 227                         if (rm->rdma.op_active &&
 228                             test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) {
 229                                 spin_lock_irqsave(&conn->c_lock, flags);
 230                                 if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags))
 231                                         list_move(&rm->m_conn_item, &to_be_dropped);
 232                                 spin_unlock_irqrestore(&conn->c_lock, flags);
 233                                 continue;
 234                         }
 235
 236                         /* Require an ACK every once in a while */
 237                         len = ntohl(rm->m_inc.i_hdr.h_len);
 238                         if (conn->c_unacked_packets == 0 ||
 239                             conn->c_unacked_bytes < len) {
 240                                 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
 241
 242                                 conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
 243                                 conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
 244                                 rds_stats_inc(s_send_ack_required);
 245                         } else {
 246                                 conn->c_unacked_bytes -= len;
 247                                 conn->c_unacked_packets--;
 248                         }
 249
 250                         conn->c_xmit_rm = rm;
 251                 }
 252
 253                 /* The transport either sends the whole rdma or none of it */
 254                 if (rm->rdma.op_active && !conn->c_xmit_rdma_sent) {
 255                         rm->m_final_op = &rm->rdma;
 256                         ret = conn->c_trans->xmit_rdma(conn, &rm->rdma);
 257                         if (ret)
 258                                 break;
 259                         conn->c_xmit_rdma_sent = 1;
 260
 261                         /* The transport owns the mapped memory for now.
 262                          * You can't unmap it while it's on the send queue */
 263                         set_bit(RDS_MSG_MAPPED, &rm->m_flags);
 264                 }
 265
 266                 if (rm->atomic.op_active && !conn->c_xmit_atomic_sent) {
 267                         rm->m_final_op = &rm->atomic;
 268                         ret = conn->c_trans->xmit_atomic(conn, &rm->atomic);
 269                         if (ret)
 270                                 break;
 271                         conn->c_xmit_atomic_sent = 1;
 272
 273                         /* The transport owns the mapped memory for now.
 274                          * You can't unmap it while it's on the send queue */
 275                         set_bit(RDS_MSG_MAPPED, &rm->m_flags);
 276                 }
 277
 278                 /*
 279                  * A number of cases require an RDS header to be sent
 280                  * even if there is no data.
 281                  * We permit 0-byte sends; rds-ping depends on this.
 282                  * However, if there are exclusively attached silent ops,
 283                  * we skip the hdr/data send, to enable silent operation.
 284                  */
 285                 if (rm->data.op_nents == 0) {
 286                         int ops_present;
 287                         int all_ops_are_silent = 1;
 288
 289                         ops_present = (rm->atomic.op_active || rm->rdma.op_active);
 290                         if (rm->atomic.op_active && !rm->atomic.op_silent)
 291                                 all_ops_are_silent = 0;
 292                         if (rm->rdma.op_active && !rm->rdma.op_silent)
 293                                 all_ops_are_silent = 0;
 294
 295                         if (ops_present && all_ops_are_silent
 296                             && !rm->m_rdma_cookie)
 297                                 rm->data.op_active = 0;
 298                 }
 299
 300                 if (rm->data.op_active && !conn->c_xmit_data_sent) {
 301                         rm->m_final_op = &rm->data;
 302                         ret = conn->c_trans->xmit(conn, rm,
 303                                                   conn->c_xmit_hdr_off,
 304                                                   conn->c_xmit_sg,
 305                                                   conn->c_xmit_data_off);
 306                         if (ret <= 0)
 307                                 break;
 308
 309                         if (conn->c_xmit_hdr_off < sizeof(struct rds_header)) {
 310                                 tmp = min_t(int, ret,
 311                                             sizeof(struct rds_header) -
 312                                             conn->c_xmit_hdr_off);
 313                                 conn->c_xmit_hdr_off += tmp;
 314                                 ret -= tmp;
 315                         }
 316
 317                         sg = &rm->data.op_sg[conn->c_xmit_sg];
 318                         while (ret) {
 319                                 tmp = min_t(int, ret, sg->length -
 320                                                       conn->c_xmit_data_off);
 321                                 conn->c_xmit_data_off += tmp;
 322                                 ret -= tmp;
 323                                 if (conn->c_xmit_data_off == sg->length) {
 324                                         conn->c_xmit_data_off = 0;
 325                                         sg++;
 326                                         conn->c_xmit_sg++;
 327                                         BUG_ON(ret != 0 &&
 328                                                conn->c_xmit_sg == rm->data.op_nents);
 329                                 }
 330                         }
 331
 332                         if (conn->c_xmit_hdr_off == sizeof(struct rds_header) &&
 333                             (conn->c_xmit_sg == rm->data.op_nents))
 334                                 conn->c_xmit_data_sent = 1;
 335                 }
 336
 337                 /*
 338                  * A rm will only take multiple times through this loop
 339                  * if there is a data op. Thus, if the data is sent (or there was
 340                  * none), then we're done with the rm.
 341                  */
 342                 if (!rm->data.op_active || conn->c_xmit_data_sent) {
 343                         conn->c_xmit_rm = NULL;
 344                         conn->c_xmit_sg = 0;
 345                         conn->c_xmit_hdr_off = 0;
 346                         conn->c_xmit_data_off = 0;
 347                         conn->c_xmit_rdma_sent = 0;
 348                         conn->c_xmit_atomic_sent = 0;
 349                         conn->c_xmit_data_sent = 0;
 350
 351                         rds_message_put(rm);
 352                 }
 353         }
 354
 355         if (conn->c_trans->xmit_complete)
 356                 conn->c_trans->xmit_complete(conn);
 357
 358         release_in_xmit(conn);
 359
 360         /* Nuke any messages we decided not to retransmit. */
 361         if (!list_empty(&to_be_dropped)) {
 362                 /* irqs on here, so we can put(), unlike above */
 363                 list_for_each_entry(rm, &to_be_dropped, m_conn_item)
 364                         rds_message_put(rm);
 365                 rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED);
 366         }
 367
 368         /*
 369          * Other senders can queue a message after we last test the send queue
 370          * but before we clear RDS_IN_XMIT.  In that case they'd back off and
 371          * not try and send their newly queued message.  We need to check the
 372          * send queue after having cleared RDS_IN_XMIT so that their message
 373          * doesn't get stuck on the send queue.
 374          *
 375          * If the transport cannot continue (i.e ret != 0), then it must
 376          * call us when more room is available, such as from the tx
 377          * completion handler.
 378          */
 379         if (ret == 0) {
 380                 smp_mb();
 381                 if (!list_empty(&conn->c_send_queue)) {
 382                         rds_stats_inc(s_send_lock_queue_raced);
 383                         goto restart;
 384                 }
 385         }
 386 out:
 387         return ret;
 388 }
 389
 390 static void rds_send_sndbuf_remove(struct rds_sock *rs, struct rds_message *rm)
 391 {
 392         u32 len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
 393
 394         assert_spin_locked(&rs->rs_lock);
 395
 396         BUG_ON(rs->rs_snd_bytes < len);
 397         rs->rs_snd_bytes -= len;
 398
 399         if (rs->rs_snd_bytes == 0)
 400                 rds_stats_inc(s_send_queue_empty);
 401 }
 402
 403 static inline int rds_send_is_acked(struct rds_message *rm, u64 ack,
 404                                     is_acked_func is_acked)
 405 {
 406         if (is_acked)
 407                 return is_acked(rm, ack);
 408         return be64_to_cpu(rm->m_inc.i_hdr.h_sequence) <= ack;
 409 }
 410
 411 /*
 412  * This is pretty similar to what happens below in the ACK
 413  * handling code - except that we call here as soon as we get
 414  * the IB send completion on the RDMA op and the accompanying
 415  * message.
 416  */
 417 void rds_rdma_send_complete(struct rds_message *rm, int status)
 418 {
 419         struct rds_sock *rs = NULL;
 420         struct rm_rdma_op *ro;
 421         struct rds_notifier *notifier;
 422         unsigned long flags;
 423
 424         spin_lock_irqsave(&rm->m_rs_lock, flags);
 425
 426         ro = &rm->rdma;
 427         if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) &&
 428             ro->op_active && ro->op_notify && ro->op_notifier) {
 429                 notifier = ro->op_notifier;
 430                 rs = rm->m_rs;
 431                 sock_hold(rds_rs_to_sk(rs));
 432
 433                 notifier->n_status = status;
 434                 spin_lock(&rs->rs_lock);
 435                 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
 436                 spin_unlock(&rs->rs_lock);
 437
 438                 ro->op_notifier = NULL;
 439         }
 440
 441         spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 442
 443         if (rs) {
 444                 rds_wake_sk_sleep(rs);
 445                 sock_put(rds_rs_to_sk(rs));
 446         }
 447 }
 448 EXPORT_SYMBOL_GPL(rds_rdma_send_complete);
 449
 450 /*
 451  * Just like above, except looks at atomic op
 452  */
 453 void rds_atomic_send_complete(struct rds_message *rm, int status)
 454 {
 455         struct rds_sock *rs = NULL;
 456         struct rm_atomic_op *ao;
 457         struct rds_notifier *notifier;
 458         unsigned long flags;
 459
 460         spin_lock_irqsave(&rm->m_rs_lock, flags);
 461
 462         ao = &rm->atomic;
 463         if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags)
 464             && ao->op_active && ao->op_notify && ao->op_notifier) {
 465                 notifier = ao->op_notifier;
 466                 rs = rm->m_rs;
 467                 sock_hold(rds_rs_to_sk(rs));
 468
 469                 notifier->n_status = status;
 470                 spin_lock(&rs->rs_lock);
 471                 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
 472                 spin_unlock(&rs->rs_lock);
 473
 474                 ao->op_notifier = NULL;
 475         }
 476
 477         spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 478
 479         if (rs) {
 480                 rds_wake_sk_sleep(rs);
 481                 sock_put(rds_rs_to_sk(rs));
 482         }
 483 }
 484 EXPORT_SYMBOL_GPL(rds_atomic_send_complete);
 485
 486 /*
 487  * This is the same as rds_rdma_send_complete except we
 488  * don't do any locking - we have all the ingredients (message,
 489  * socket, socket lock) and can just move the notifier.
 490  */
 491 static inline void
 492 __rds_send_complete(struct rds_sock *rs, struct rds_message *rm, int status)
 493 {
 494         struct rm_rdma_op *ro;
 495         struct rm_atomic_op *ao;
 496
 497         ro = &rm->rdma;
 498         if (ro->op_active && ro->op_notify && ro->op_notifier) {
 499                 ro->op_notifier->n_status = status;
 500                 list_add_tail(&ro->op_notifier->n_list, &rs->rs_notify_queue);
 501                 ro->op_notifier = NULL;
 502         }
 503
 504         ao = &rm->atomic;
 505         if (ao->op_active && ao->op_notify && ao->op_notifier) {
 506                 ao->op_notifier->n_status = status;
 507                 list_add_tail(&ao->op_notifier->n_list, &rs->rs_notify_queue);
 508                 ao->op_notifier = NULL;
 509         }
 510
 511         /* No need to wake the app - caller does this */
 512 }
 513
 514 /*
 515  * This is called from the IB send completion when we detect
 516  * a RDMA operation that failed with remote access error.
 517  * So speed is not an issue here.
 518  */
 519 struct rds_message *rds_send_get_message(struct rds_connection *conn,
 520                                          struct rm_rdma_op *op)
 521 {
 522         struct rds_message *rm, *tmp, *found = NULL;
 523         unsigned long flags;
 524
 525         spin_lock_irqsave(&conn->c_lock, flags);
 526
 527         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
 528                 if (&rm->rdma == op) {
 529                         atomic_inc(&rm->m_refcount);
 530                         found = rm;
 531                         goto out;
 532                 }
 533         }
 534
 535         list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
 536                 if (&rm->rdma == op) {
 537                         atomic_inc(&rm->m_refcount);
 538                         found = rm;
 539                         break;
 540                 }
 541         }
 542
 543 out:
 544         spin_unlock_irqrestore(&conn->c_lock, flags);
 545
 546         return found;
 547 }
 548 EXPORT_SYMBOL_GPL(rds_send_get_message);
 549
 550 /*
 551  * This removes messages from the socket's list if they're on it.  The list
 552  * argument must be private to the caller, we must be able to modify it
 553  * without locks.  The messages must have a reference held for their
 554  * position on the list.  This function will drop that reference after
 555  * removing the messages from the 'messages' list regardless of if it found
 556  * the messages on the socket list or not.
 557  */
 558 void rds_send_remove_from_sock(struct list_head *messages, int status)
 559 {
 560         unsigned long flags;
 561         struct rds_sock *rs = NULL;
 562         struct rds_message *rm;
 563
 564         while (!list_empty(messages)) {
 565                 int was_on_sock = 0;
 566
 567                 rm = list_entry(messages->next, struct rds_message,
 568                                 m_conn_item);
 569                 list_del_init(&rm->m_conn_item);
 570
 571                 /*
 572                  * If we see this flag cleared then we're *sure* that someone
 573                  * else beat us to removing it from the sock.  If we race
 574                  * with their flag update we'll get the lock and then really
 575                  * see that the flag has been cleared.
 576                  *
 577                  * The message spinlock makes sure nobody clears rm->m_rs
 578                  * while we're messing with it. It does not prevent the
 579                  * message from being removed from the socket, though.
 580                  */
 581                 spin_lock_irqsave(&rm->m_rs_lock, flags);
 582                 if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags))
 583                         goto unlock_and_drop;
 584
 585                 if (rs != rm->m_rs) {
 586                         if (rs) {
 587                                 rds_wake_sk_sleep(rs);
 588                                 sock_put(rds_rs_to_sk(rs));
 589                         }
 590                         rs = rm->m_rs;
 591                         sock_hold(rds_rs_to_sk(rs));
 592                 }
 593                 spin_lock(&rs->rs_lock);
 594
 595                 if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) {
 596                         struct rm_rdma_op *ro = &rm->rdma;
 597                         struct rds_notifier *notifier;
 598
 599                         list_del_init(&rm->m_sock_item);
 600                         rds_send_sndbuf_remove(rs, rm);
 601
 602                         if (ro->op_active && ro->op_notifier &&
 603                                (ro->op_notify || (ro->op_recverr && status))) {
 604                                 notifier = ro->op_notifier;
 605                                 list_add_tail(&notifier->n_list,
 606                                                 &rs->rs_notify_queue);
 607                                 if (!notifier->n_status)
 608                                         notifier->n_status = status;
 609                                 rm->rdma.op_notifier = NULL;
 610                         }
 611                         was_on_sock = 1;
 612                         rm->m_rs = NULL;
 613                 }
 614                 spin_unlock(&rs->rs_lock);
 615
 616 unlock_and_drop:
 617                 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 618                 rds_message_put(rm);
 619                 if (was_on_sock)
 620                         rds_message_put(rm);
 621         }
 622
 623         if (rs) {
 624                 rds_wake_sk_sleep(rs);
 625                 sock_put(rds_rs_to_sk(rs));
 626         }
 627 }
 628
 629 /*
 630  * Transports call here when they've determined that the receiver queued
 631  * messages up to, and including, the given sequence number.  Messages are
 632  * moved to the retrans queue when rds_send_xmit picks them off the send
 633  * queue. This means that in the TCP case, the message may not have been
 634  * assigned the m_ack_seq yet - but that's fine as long as tcp_is_acked
 635  * checks the RDS_MSG_HAS_ACK_SEQ bit.
 636  *
 637  * XXX It's not clear to me how this is safely serialized with socket
 638  * destruction.  Maybe it should bail if it sees SOCK_DEAD.
 639  */
 640 void rds_send_drop_acked(struct rds_connection *conn, u64 ack,
 641                          is_acked_func is_acked)
 642 {
 643         struct rds_message *rm, *tmp;
 644         unsigned long flags;
 645         LIST_HEAD(list);
 646
 647         spin_lock_irqsave(&conn->c_lock, flags);
 648
 649         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
 650                 if (!rds_send_is_acked(rm, ack, is_acked))
 651                         break;
 652
 653                 list_move(&rm->m_conn_item, &list);
 654                 clear_bit(RDS_MSG_ON_CONN, &rm->m_flags);
 655         }
 656
 657         /* order flag updates with spin locks */
 658         if (!list_empty(&list))
 659                 smp_mb__after_clear_bit();
 660
 661         spin_unlock_irqrestore(&conn->c_lock, flags);
 662
 663         /* now remove the messages from the sock list as needed */
 664         rds_send_remove_from_sock(&list, RDS_RDMA_SUCCESS);
 665 }
 666 EXPORT_SYMBOL_GPL(rds_send_drop_acked);
 667
 668 void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest)
 669 {
 670         struct rds_message *rm, *tmp;
 671         struct rds_connection *conn;
 672         unsigned long flags;
 673         LIST_HEAD(list);
 674
 675         /* get all the messages we're dropping under the rs lock */
 676         spin_lock_irqsave(&rs->rs_lock, flags);
 677
 678         list_for_each_entry_safe(rm, tmp, &rs->rs_send_queue, m_sock_item) {
 679                 if (dest && (dest->sin_addr.s_addr != rm->m_daddr ||
 680                              dest->sin_port != rm->m_inc.i_hdr.h_dport))
 681                         continue;
 682
 683                 list_move(&rm->m_sock_item, &list);
 684                 rds_send_sndbuf_remove(rs, rm);
 685                 clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
 686         }
 687
 688         /* order flag updates with the rs lock */
 689         smp_mb__after_clear_bit();
 690
 691         spin_unlock_irqrestore(&rs->rs_lock, flags);
 692
 693         if (list_empty(&list))
 694                 return;
 695
 696         /* Remove the messages from the conn */
 697         list_for_each_entry(rm, &list, m_sock_item) {
 698
 699                 conn = rm->m_inc.i_conn;
 700
 701                 spin_lock_irqsave(&conn->c_lock, flags);
 702                 /*
 703                  * Maybe someone else beat us to removing rm from the conn.
 704                  * If we race with their flag update we'll get the lock and
 705                  * then really see that the flag has been cleared.
 706                  */
 707                 if (!test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) {
 708                         spin_unlock_irqrestore(&conn->c_lock, flags);
 709                         continue;
 710                 }
 711                 list_del_init(&rm->m_conn_item);
 712                 spin_unlock_irqrestore(&conn->c_lock, flags);
 713
 714                 /*
 715                  * Couldn't grab m_rs_lock in top loop (lock ordering),
 716                  * but we can now.
 717                  */
 718                 spin_lock_irqsave(&rm->m_rs_lock, flags);
 719
 720                 spin_lock(&rs->rs_lock);
 721                 __rds_send_complete(rs, rm, RDS_RDMA_CANCELED);
 722                 spin_unlock(&rs->rs_lock);
 723
 724                 rm->m_rs = NULL;
 725                 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 726
 727                 rds_message_put(rm);
 728         }
 729
 730         rds_wake_sk_sleep(rs);
 731
 732         while (!list_empty(&list)) {
 733                 rm = list_entry(list.next, struct rds_message, m_sock_item);
 734                 list_del_init(&rm->m_sock_item);
 735
 736                 rds_message_wait(rm);
 737                 rds_message_put(rm);
 738         }
 739 }
 740
 741 /*
 742  * we only want this to fire once so we use the callers 'queued'.  It's
 743  * possible that another thread can race with us and remove the
 744  * message from the flow with RDS_CANCEL_SENT_TO.
 745  */
 746 static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn,
 747                              struct rds_message *rm, __be16 sport,
 748                              __be16 dport, int *queued)
 749 {
 750         unsigned long flags;
 751         u32 len;
 752
 753         if (*queued)
 754                 goto out;
 755
 756         len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
 757
 758         /* this is the only place which holds both the socket's rs_lock
 759          * and the connection's c_lock */
 760         spin_lock_irqsave(&rs->rs_lock, flags);
 761
 762         /*
 763          * If there is a little space in sndbuf, we don't queue anything,
 764          * and userspace gets -EAGAIN. But poll() indicates there's send
 765          * room. This can lead to bad behavior (spinning) if snd_bytes isn't
 766          * freed up by incoming acks. So we check the *old* value of
 767          * rs_snd_bytes here to allow the last msg to exceed the buffer,
 768          * and poll() now knows no more data can be sent.
 769          */
 770         if (rs->rs_snd_bytes < rds_sk_sndbuf(rs)) {
 771                 rs->rs_snd_bytes += len;
 772
 773                 /* let recv side know we are close to send space exhaustion.
 774                  * This is probably not the optimal way to do it, as this
 775                  * means we set the flag on *all* messages as soon as our
 776                  * throughput hits a certain threshold.
 777                  */
 778                 if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2)
 779                         __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
 780
 781                 list_add_tail(&rm->m_sock_item, &rs->rs_send_queue);
 782                 set_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
 783                 rds_message_addref(rm);
 784                 rm->m_rs = rs;
 785
 786                 /* The code ordering is a little weird, but we're
 787                    trying to minimize the time we hold c_lock */
 788                 rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport, 0);
 789                 rm->m_inc.i_conn = conn;
 790                 rds_message_addref(rm);
 791
 792                 spin_lock(&conn->c_lock);
 793                 rm->m_inc.i_hdr.h_sequence = cpu_to_be64(conn->c_next_tx_seq++);
 794                 list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
 795                 set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
 796                 spin_unlock(&conn->c_lock);
 797
 798                 rdsdebug("queued msg %p len %d, rs %p bytes %d seq %llu\n",
 799                          rm, len, rs, rs->rs_snd_bytes,
 800                          (unsigned long long)be64_to_cpu(rm->m_inc.i_hdr.h_sequence));
 801
 802                 *queued = 1;
 803         }
 804
 805         spin_unlock_irqrestore(&rs->rs_lock, flags);
 806 out:
 807         return *queued;
 808 }
 809
 810 /*
 811  * rds_message is getting to be quite complicated, and we'd like to allocate
 812  * it all in one go. This figures out how big it needs to be up front.
 813  */
 814 static int rds_rm_size(struct msghdr *msg, int data_len)
 815 {
 816         struct cmsghdr *cmsg;
 817         int size = 0;
 818         int cmsg_groups = 0;
 819         int retval;
 820
 821         for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
 822                 if (!CMSG_OK(msg, cmsg))
 823                         return -EINVAL;
 824
 825                 if (cmsg->cmsg_level != SOL_RDS)
 826                         continue;
 827
 828                 switch (cmsg->cmsg_type) {
 829                 case RDS_CMSG_RDMA_ARGS:
 830                         cmsg_groups |= 1;
 831                         retval = rds_rdma_extra_size(CMSG_DATA(cmsg));
 832                         if (retval < 0)
 833                                 return retval;
 834                         size += retval;
 835
 836                         break;
 837
 838                 case RDS_CMSG_RDMA_DEST:
 839                 case RDS_CMSG_RDMA_MAP:
 840                         cmsg_groups |= 2;
 841                         /* these are valid but do no add any size */
 842                         break;
 843
 844                 case RDS_CMSG_ATOMIC_CSWP:
 845                 case RDS_CMSG_ATOMIC_FADD:
 846                 case RDS_CMSG_MASKED_ATOMIC_CSWP:
 847                 case RDS_CMSG_MASKED_ATOMIC_FADD:
 848                         cmsg_groups |= 1;
 849                         size += sizeof(struct scatterlist);
 850                         break;
 851
 852                 default:
 853                         return -EINVAL;
 854                 }
 855
 856         }
 857
 858         size += ceil(data_len, PAGE_SIZE) * sizeof(struct scatterlist);
 859
 860         /* Ensure (DEST, MAP) are never used with (ARGS, ATOMIC) */
 861         if (cmsg_groups == 3)
 862                 return -EINVAL;
 863
 864         return size;
 865 }
 866
 867 static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
 868                          struct msghdr *msg, int *allocated_mr)
 869 {
 870         struct cmsghdr *cmsg;
 871         int ret = 0;
 872
 873         for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
 874                 if (!CMSG_OK(msg, cmsg))
 875                         return -EINVAL;
 876
 877                 if (cmsg->cmsg_level != SOL_RDS)
 878                         continue;
 879
 880                 /* As a side effect, RDMA_DEST and RDMA_MAP will set
 881                  * rm->rdma.m_rdma_cookie and rm->rdma.m_rdma_mr.
 882                  */
 883                 switch (cmsg->cmsg_type) {
 884                 case RDS_CMSG_RDMA_ARGS:
 885                         ret = rds_cmsg_rdma_args(rs, rm, cmsg);
 886                         break;
 887
 888                 case RDS_CMSG_RDMA_DEST:
 889                         ret = rds_cmsg_rdma_dest(rs, rm, cmsg);
 890                         break;
 891
 892                 case RDS_CMSG_RDMA_MAP:
 893                         ret = rds_cmsg_rdma_map(rs, rm, cmsg);
 894                         if (!ret)
 895                                 *allocated_mr = 1;
 896                         break;
 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                         ret = rds_cmsg_atomic(rs, rm, cmsg);
 902                         break;
 903
 904                 default:
 905                         return -EINVAL;
 906                 }
 907
 908                 if (ret)
 909                         break;
 910         }
 911
 912         return ret;
 913 }
 914
 915 int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
 916                 size_t payload_len)
 917 {
 918         struct sock *sk = sock->sk;
 919         struct rds_sock *rs = rds_sk_to_rs(sk);
 920         struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name;
 921         __be32 daddr;
 922         __be16 dport;
 923         struct rds_message *rm = NULL;
 924         struct rds_connection *conn;
 925         int ret = 0;
 926         int queued = 0, allocated_mr = 0;
 927         int nonblock = msg->msg_flags & MSG_DONTWAIT;
 928         long timeo = sock_sndtimeo(sk, nonblock);
 929
 930         /* Mirror Linux UDP mirror of BSD error message compatibility */
 931         /* XXX: Perhaps MSG_MORE someday */
 932         if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) {
 933                 printk(KERN_INFO "msg_flags 0x%08X\n", msg->msg_flags);
 934                 ret = -EOPNOTSUPP;
 935                 goto out;
 936         }
 937
 938         if (msg->msg_namelen) {
 939                 /* XXX fail non-unicast destination IPs? */
 940                 if (msg->msg_namelen < sizeof(*usin) || usin->sin_family != AF_INET) {
 941                         ret = -EINVAL;
 942                         goto out;
 943                 }
 944                 daddr = usin->sin_addr.s_addr;
 945                 dport = usin->sin_port;
 946         } else {
 947                 /* We only care about consistency with ->connect() */
 948                 lock_sock(sk);
 949                 daddr = rs->rs_conn_addr;
 950                 dport = rs->rs_conn_port;
 951                 release_sock(sk);
 952         }
 953
 954         /* racing with another thread binding seems ok here */
 955         if (daddr == 0 || rs->rs_bound_addr == 0) {
 956                 ret = -ENOTCONN; /* XXX not a great errno */
 957                 goto out;
 958         }
 959
 960         /* size of rm including all sgs */
 961         ret = rds_rm_size(msg, payload_len);
 962         if (ret < 0)
 963                 goto out;
 964
 965         rm = rds_message_alloc(ret, GFP_KERNEL);
 966         if (!rm) {
 967                 ret = -ENOMEM;
 968                 goto out;
 969         }
 970
 971         /* Attach data to the rm */
 972         if (payload_len) {
 973                 rm->data.op_sg = rds_message_alloc_sgs(rm, ceil(payload_len, PAGE_SIZE));
 974                 ret = rds_message_copy_from_user(rm, msg->msg_iov, payload_len);
 975                 if (ret)
 976                         goto out;
 977         }
 978         rm->data.op_active = 1;
 979
 980         rm->m_daddr = daddr;
 981
 982         /* rds_conn_create has a spinlock that runs with IRQ off.
 983          * Caching the conn in the socket helps a lot. */
 984         if (rs->rs_conn && rs->rs_conn->c_faddr == daddr)
 985                 conn = rs->rs_conn;
 986         else {
 987                 conn = rds_conn_create_outgoing(rs->rs_bound_addr, daddr,
 988                                         rs->rs_transport,
 989                                         sock->sk->sk_allocation);
 990                 if (IS_ERR(conn)) {
 991                         ret = PTR_ERR(conn);
 992                         goto out;
 993                 }
 994                 rs->rs_conn = conn;
 995         }
 996
 997         /* Parse any control messages the user may have included. */
 998         ret = rds_cmsg_send(rs, rm, msg, &allocated_mr);
 999         if (ret)
1000                 goto out;
1001
1002         if (rm->rdma.op_active && !conn->c_trans->xmit_rdma) {
1003                 if (printk_ratelimit())
1004                         printk(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",
1005                                &rm->rdma, conn->c_trans->xmit_rdma);
1006                 ret = -EOPNOTSUPP;
1007                 goto out;
1008         }
1009
1010         if (rm->atomic.op_active && !conn->c_trans->xmit_atomic) {
1011                 if (printk_ratelimit())
1012                         printk(KERN_NOTICE "atomic_op %p conn xmit_atomic %p\n",
1013                                &rm->atomic, conn->c_trans->xmit_atomic);
1014                 ret = -EOPNOTSUPP;
1015                 goto out;
1016         }
1017
1018         rds_conn_connect_if_down(conn);
1019
1020         ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);
1021         if (ret) {
1022                 rs->rs_seen_congestion = 1;
1023                 goto out;
1024         }
1025
1026         while (!rds_send_queue_rm(rs, conn, rm, rs->rs_bound_port,
1027                                   dport, &queued)) {
1028                 rds_stats_inc(s_send_queue_full);
1029                 /* XXX make sure this is reasonable */
1030                 if (payload_len > rds_sk_sndbuf(rs)) {
1031                         ret = -EMSGSIZE;
1032                         goto out;
1033                 }
1034                 if (nonblock) {
1035                         ret = -EAGAIN;
1036                         goto out;
1037                 }
1038
1039                 timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
1040                                         rds_send_queue_rm(rs, conn, rm,
1041                                                           rs->rs_bound_port,
1042                                                           dport,
1043                                                           &queued),
1044                                         timeo);
1045                 rdsdebug("sendmsg woke queued %d timeo %ld\n", queued, timeo);
1046                 if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
1047                         continue;
1048
1049                 ret = timeo;
1050                 if (ret == 0)
1051                         ret = -ETIMEDOUT;
1052                 goto out;
1053         }
1054
1055         /*
1056          * By now we've committed to the send.  We reuse rds_send_worker()
1057          * to retry sends in the rds thread if the transport asks us to.
1058          */
1059         rds_stats_inc(s_send_queued);
1060
1061         if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
1062                 rds_send_xmit(conn);
1063
1064         rds_message_put(rm);
1065         return payload_len;
1066
1067 out:
1068         /* If the user included a RDMA_MAP cmsg, we allocated a MR on the fly.
1069          * If the sendmsg goes through, we keep the MR. If it fails with EAGAIN
1070          * or in any other way, we need to destroy the MR again */
1071         if (allocated_mr)
1072                 rds_rdma_unuse(rs, rds_rdma_cookie_key(rm->m_rdma_cookie), 1);
1073
1074         if (rm)
1075                 rds_message_put(rm);
1076         return ret;
1077 }
1078
1079 /*
1080  * Reply to a ping packet.
1081  */
1082 int
1083 rds_send_pong(struct rds_connection *conn, __be16 dport)
1084 {
1085         struct rds_message *rm;
1086         unsigned long flags;
1087         int ret = 0;
1088
1089         rm = rds_message_alloc(0, GFP_ATOMIC);
1090         if (!rm) {
1091                 ret = -ENOMEM;
1092                 goto out;
1093         }
1094
1095         rm->m_daddr = conn->c_faddr;
1096         rm->data.op_active = 1;
1097
1098         rds_conn_connect_if_down(conn);
1099
1100         ret = rds_cong_wait(conn->c_fcong, dport, 1, NULL);
1101         if (ret)
1102                 goto out;
1103
1104         spin_lock_irqsave(&conn->c_lock, flags);
1105         list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
1106         set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
1107         rds_message_addref(rm);
1108         rm->m_inc.i_conn = conn;
1109
1110         rds_message_populate_header(&rm->m_inc.i_hdr, 0, dport,
1111                                     conn->c_next_tx_seq);
1112         conn->c_next_tx_seq++;
1113         spin_unlock_irqrestore(&conn->c_lock, flags);
1114
1115         rds_stats_inc(s_send_queued);
1116         rds_stats_inc(s_send_pong);
1117
1118         if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
1119                 rds_send_xmit(conn);
1120
1121         rds_message_put(rm);
1122         return 0;
1123
1124 out:
1125         if (rm)
1126                 rds_message_put(rm);
1127         return ret;
1128 }