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. Caller must hold c_send_lock when calling here.
  57  */
  58 void rds_send_reset(struct rds_connection *conn)
  59 {
  60         struct rds_message *rm, *tmp;
  61         unsigned long flags;
  62
  63         spin_lock_irqsave(&conn->c_send_lock, flags);
  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                 spin_unlock_irqrestore(&conn->c_send_lock, flags);
  73
  74                 rds_message_put(rm);
  75         } else {
  76                 spin_unlock_irqrestore(&conn->c_send_lock, flags);
  77         }
  78
  79         conn->c_xmit_sg = 0;
  80         conn->c_xmit_hdr_off = 0;
  81         conn->c_xmit_data_off = 0;
  82         conn->c_xmit_atomic_sent = 0;
  83         conn->c_xmit_rdma_sent = 0;
  84         conn->c_xmit_data_sent = 0;
  85
  86         conn->c_map_queued = 0;
  87
  88         conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
  89         conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
  90
  91         /* Mark messages as retransmissions, and move them to the send q */
  92         spin_lock_irqsave(&conn->c_lock, flags);
  93         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
  94                 set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
  95                 set_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags);
  96         }
  97         list_splice_init(&conn->c_retrans, &conn->c_send_queue);
  98         spin_unlock_irqrestore(&conn->c_lock, flags);
  99 }
 100
 101 /*
 102  * We're making the concious trade-off here to only send one message
 103  * down the connection at a time.
 104  *   Pro:
 105  *      - tx queueing is a simple fifo list
 106  *      - reassembly is optional and easily done by transports per conn
 107  *      - no per flow rx lookup at all, straight to the socket
 108  *      - less per-frag memory and wire overhead
 109  *   Con:
 110  *      - queued acks can be delayed behind large messages
 111  *   Depends:
 112  *      - small message latency is higher behind queued large messages
 113  *      - large message latency isn't starved by intervening small sends
 114  */
 115 int rds_send_xmit(struct rds_connection *conn)
 116 {
 117         struct rds_message *rm;
 118         unsigned long flags;
 119         unsigned int tmp;
 120         struct scatterlist *sg;
 121         int ret = 0;
 122         int gen = 0;
 123         LIST_HEAD(to_be_dropped);
 124
 125 restart:
 126         if (!rds_conn_up(conn))
 127                 goto out;
 128
 129         /*
 130          * sendmsg calls here after having queued its message on the send
 131          * queue.  We only have one task feeding the connection at a time.  If
 132          * another thread is already feeding the queue then we back off.  This
 133          * avoids blocking the caller and trading per-connection data between
 134          * caches per message.
 135          */
 136         if (!spin_trylock_irqsave(&conn->c_send_lock, flags)) {
 137                 rds_stats_inc(s_send_lock_contention);
 138                 ret = -ENOMEM;
 139                 goto out;
 140         }
 141         atomic_inc(&conn->c_senders);
 142
 143         if (conn->c_trans->xmit_prepare)
 144                 conn->c_trans->xmit_prepare(conn);
 145
 146         gen = atomic_inc_return(&conn->c_send_generation);
 147
 148         /*
 149          * spin trying to push headers and data down the connection until
 150          * the connection doesn't make forward progress.
 151          */
 152         while (1) {
 153
 154                 rm = conn->c_xmit_rm;
 155
 156                 /*
 157                  * If between sending messages, we can send a pending congestion
 158                  * map update.
 159                  */
 160                 if (!rm && test_and_clear_bit(0, &conn->c_map_queued)) {
 161                         rm = rds_cong_update_alloc(conn);
 162                         if (IS_ERR(rm)) {
 163                                 ret = PTR_ERR(rm);
 164                                 break;
 165                         }
 166                         rm->data.op_active = 1;
 167
 168                         conn->c_xmit_rm = rm;
 169                 }
 170
 171                 /*
 172                  * If not already working on one, grab the next message.
 173                  *
 174                  * c_xmit_rm holds a ref while we're sending this message down
 175                  * the connction.  We can use this ref while holding the
 176                  * send_sem.. rds_send_reset() is serialized with it.
 177                  */
 178                 if (!rm) {
 179                         unsigned int len;
 180
 181                         spin_lock(&conn->c_lock);
 182
 183                         if (!list_empty(&conn->c_send_queue)) {
 184                                 rm = list_entry(conn->c_send_queue.next,
 185                                                 struct rds_message,
 186                                                 m_conn_item);
 187                                 rds_message_addref(rm);
 188
 189                                 /*
 190                                  * Move the message from the send queue to the retransmit
 191                                  * list right away.
 192                                  */
 193                                 list_move_tail(&rm->m_conn_item, &conn->c_retrans);
 194                         }
 195
 196                         spin_unlock(&conn->c_lock);
 197
 198                         if (!rm)
 199                                 break;
 200
 201                         /* Unfortunately, the way Infiniband deals with
 202                          * RDMA to a bad MR key is by moving the entire
 203                          * queue pair to error state. We cold possibly
 204                          * recover from that, but right now we drop the
 205                          * connection.
 206                          * Therefore, we never retransmit messages with RDMA ops.
 207                          */
 208                         if (rm->rdma.op_active &&
 209                             test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) {
 210                                 spin_lock(&conn->c_lock);
 211                                 if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags))
 212                                         list_move(&rm->m_conn_item, &to_be_dropped);
 213                                 spin_unlock(&conn->c_lock);
 214                                 continue;
 215                         }
 216
 217                         /* Require an ACK every once in a while */
 218                         len = ntohl(rm->m_inc.i_hdr.h_len);
 219                         if (conn->c_unacked_packets == 0 ||
 220                             conn->c_unacked_bytes < len) {
 221                                 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
 222
 223                                 conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
 224                                 conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
 225                                 rds_stats_inc(s_send_ack_required);
 226                         } else {
 227                                 conn->c_unacked_bytes -= len;
 228                                 conn->c_unacked_packets--;
 229                         }
 230
 231                         conn->c_xmit_rm = rm;
 232                 }
 233
 234                 /* The transport either sends the whole rdma or none of it */
 235                 if (rm->rdma.op_active && !conn->c_xmit_rdma_sent) {
 236                         rds_message_addref(rm);
 237                         rm->m_final_op = &rm->rdma;
 238                         ret = conn->c_trans->xmit_rdma(conn, &rm->rdma);
 239                         if (ret) {
 240                                 rds_message_put(rm);
 241                                 break;
 242                         }
 243                         conn->c_xmit_rdma_sent = 1;
 244
 245                         /* The transport owns the mapped memory for now.
 246                          * You can't unmap it while it's on the send queue */
 247                         set_bit(RDS_MSG_MAPPED, &rm->m_flags);
 248                 }
 249
 250                 if (rm->atomic.op_active && !conn->c_xmit_atomic_sent) {
 251                         rds_message_addref(rm);
 252                         rm->m_final_op = &rm->atomic;
 253                         ret = conn->c_trans->xmit_atomic(conn, &rm->atomic);
 254                         if (ret) {
 255                                 rds_message_put(rm);
 256                                 break;
 257                         }
 258                         conn->c_xmit_atomic_sent = 1;
 259
 260                         /* The transport owns the mapped memory for now.
 261                          * You can't unmap it while it's on the send queue */
 262                         set_bit(RDS_MSG_MAPPED, &rm->m_flags);
 263                 }
 264
 265                 /*
 266                  * A number of cases require an RDS header to be sent
 267                  * even if there is no data.
 268                  * We permit 0-byte sends; rds-ping depends on this.
 269                  * However, if there are exclusively attached silent ops,
 270                  * we skip the hdr/data send, to enable silent operation.
 271                  */
 272                 if (rm->data.op_nents == 0) {
 273                         int ops_present;
 274                         int all_ops_are_silent = 1;
 275
 276                         ops_present = (rm->atomic.op_active || rm->rdma.op_active);
 277                         if (rm->atomic.op_active && !rm->atomic.op_silent)
 278                                 all_ops_are_silent = 0;
 279                         if (rm->rdma.op_active && !rm->rdma.op_silent)
 280                                 all_ops_are_silent = 0;
 281
 282                         if (ops_present && all_ops_are_silent
 283                             && !rm->m_rdma_cookie)
 284                                 rm->data.op_active = 0;
 285                 }
 286
 287                 if (rm->data.op_active && !conn->c_xmit_data_sent) {
 288                         rm->m_final_op = &rm->data;
 289                         ret = conn->c_trans->xmit(conn, rm,
 290                                                   conn->c_xmit_hdr_off,
 291                                                   conn->c_xmit_sg,
 292                                                   conn->c_xmit_data_off);
 293                         if (ret <= 0)
 294                                 break;
 295
 296                         if (conn->c_xmit_hdr_off < sizeof(struct rds_header)) {
 297                                 tmp = min_t(int, ret,
 298                                             sizeof(struct rds_header) -
 299                                             conn->c_xmit_hdr_off);
 300                                 conn->c_xmit_hdr_off += tmp;
 301                                 ret -= tmp;
 302                         }
 303
 304                         sg = &rm->data.op_sg[conn->c_xmit_sg];
 305                         while (ret) {
 306                                 tmp = min_t(int, ret, sg->length -
 307                                                       conn->c_xmit_data_off);
 308                                 conn->c_xmit_data_off += tmp;
 309                                 ret -= tmp;
 310                                 if (conn->c_xmit_data_off == sg->length) {
 311                                         conn->c_xmit_data_off = 0;
 312                                         sg++;
 313                                         conn->c_xmit_sg++;
 314                                         BUG_ON(ret != 0 &&
 315                                                conn->c_xmit_sg == rm->data.op_nents);
 316                                 }
 317                         }
 318
 319                         if (conn->c_xmit_hdr_off == sizeof(struct rds_header) &&
 320                             (conn->c_xmit_sg == rm->data.op_nents))
 321                                 conn->c_xmit_data_sent = 1;
 322                 }
 323
 324                 /*
 325                  * A rm will only take multiple times through this loop
 326                  * if there is a data op. Thus, if the data is sent (or there was
 327                  * none), then we're done with the rm.
 328                  */
 329                 if (!rm->data.op_active || conn->c_xmit_data_sent) {
 330                         conn->c_xmit_rm = NULL;
 331                         conn->c_xmit_sg = 0;
 332                         conn->c_xmit_hdr_off = 0;
 333                         conn->c_xmit_data_off = 0;
 334                         conn->c_xmit_rdma_sent = 0;
 335                         conn->c_xmit_atomic_sent = 0;
 336                         conn->c_xmit_data_sent = 0;
 337
 338                         rds_message_put(rm);
 339                 }
 340         }
 341
 342         if (conn->c_trans->xmit_complete)
 343                 conn->c_trans->xmit_complete(conn);
 344
 345         /*
 346          * We might be racing with another sender who queued a message but
 347          * backed off on noticing that we held the c_send_lock.  If we check
 348          * for queued messages after dropping the sem then either we'll
 349          * see the queued message or the queuer will get the sem.  If we
 350          * notice the queued message then we trigger an immediate retry.
 351          *
 352          * We need to be careful only to do this when we stopped processing
 353          * the send queue because it was empty.  It's the only way we
 354          * stop processing the loop when the transport hasn't taken
 355          * responsibility for forward progress.
 356          */
 357         spin_unlock_irqrestore(&conn->c_send_lock, flags);
 358
 359         /* Nuke any messages we decided not to retransmit. */
 360         if (!list_empty(&to_be_dropped)) {
 361                 /* irqs on here, so we can put(), unlike above */
 362                 list_for_each_entry(rm, &to_be_dropped, m_conn_item)
 363                         rds_message_put(rm);
 364                 rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED);
 365         }
 366
 367         atomic_dec(&conn->c_senders);
 368
 369         /*
 370          * Other senders will see we have c_send_lock and exit. We
 371          * need to recheck the send queue and race again for c_send_lock
 372          * to make sure messages don't just sit on the send queue, if
 373          * somebody hasn't already beat us into the loop.
 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                         if (gen == atomic_read(&conn->c_send_generation)) {
 384                                 goto restart;
 385                         }
 386                 }
 387         }
 388 out:
 389         return ret;
 390 }
 391
 392 static void rds_send_sndbuf_remove(struct rds_sock *rs, struct rds_message *rm)
 393 {
 394         u32 len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
 395
 396         assert_spin_locked(&rs->rs_lock);
 397
 398         BUG_ON(rs->rs_snd_bytes < len);
 399         rs->rs_snd_bytes -= len;
 400
 401         if (rs->rs_snd_bytes == 0)
 402                 rds_stats_inc(s_send_queue_empty);
 403 }
 404
 405 static inline int rds_send_is_acked(struct rds_message *rm, u64 ack,
 406                                     is_acked_func is_acked)
 407 {
 408         if (is_acked)
 409                 return is_acked(rm, ack);
 410         return be64_to_cpu(rm->m_inc.i_hdr.h_sequence) <= ack;
 411 }
 412
 413 /*
 414  * Returns true if there are no messages on the send and retransmit queues
 415  * which have a sequence number greater than or equal to the given sequence
 416  * number.
 417  */
 418 int rds_send_acked_before(struct rds_connection *conn, u64 seq)
 419 {
 420         struct rds_message *rm, *tmp;
 421         int ret = 1;
 422
 423         spin_lock(&conn->c_lock);
 424
 425         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
 426                 if (be64_to_cpu(rm->m_inc.i_hdr.h_sequence) < seq)
 427                         ret = 0;
 428                 break;
 429         }
 430
 431         list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
 432                 if (be64_to_cpu(rm->m_inc.i_hdr.h_sequence) < seq)
 433                         ret = 0;
 434                 break;
 435         }
 436
 437         spin_unlock(&conn->c_lock);
 438
 439         return ret;
 440 }
 441
 442 /*
 443  * This is pretty similar to what happens below in the ACK
 444  * handling code - except that we call here as soon as we get
 445  * the IB send completion on the RDMA op and the accompanying
 446  * message.
 447  */
 448 void rds_rdma_send_complete(struct rds_message *rm, int status)
 449 {
 450         struct rds_sock *rs = NULL;
 451         struct rm_rdma_op *ro;
 452         struct rds_notifier *notifier;
 453         unsigned long flags;
 454
 455         spin_lock_irqsave(&rm->m_rs_lock, flags);
 456
 457         ro = &rm->rdma;
 458         if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) &&
 459             ro->op_active && ro->op_notify && ro->op_notifier) {
 460                 notifier = ro->op_notifier;
 461                 rs = rm->m_rs;
 462                 sock_hold(rds_rs_to_sk(rs));
 463
 464                 notifier->n_status = status;
 465                 spin_lock(&rs->rs_lock);
 466                 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
 467                 spin_unlock(&rs->rs_lock);
 468
 469                 ro->op_notifier = NULL;
 470         }
 471
 472         spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 473
 474         if (rs) {
 475                 rds_wake_sk_sleep(rs);
 476                 sock_put(rds_rs_to_sk(rs));
 477         }
 478 }
 479 EXPORT_SYMBOL_GPL(rds_rdma_send_complete);
 480
 481 /*
 482  * Just like above, except looks at atomic op
 483  */
 484 void rds_atomic_send_complete(struct rds_message *rm, int status)
 485 {
 486         struct rds_sock *rs = NULL;
 487         struct rm_atomic_op *ao;
 488         struct rds_notifier *notifier;
 489         unsigned long flags;
 490
 491         spin_lock_irqsave(&rm->m_rs_lock, flags);
 492
 493         ao = &rm->atomic;
 494         if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags)
 495             && ao->op_active && ao->op_notify && ao->op_notifier) {
 496                 notifier = ao->op_notifier;
 497                 rs = rm->m_rs;
 498                 sock_hold(rds_rs_to_sk(rs));
 499
 500                 notifier->n_status = status;
 501                 spin_lock(&rs->rs_lock);
 502                 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
 503                 spin_unlock(&rs->rs_lock);
 504
 505                 ao->op_notifier = NULL;
 506         }
 507
 508         spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 509
 510         if (rs) {
 511                 rds_wake_sk_sleep(rs);
 512                 sock_put(rds_rs_to_sk(rs));
 513         }
 514 }
 515 EXPORT_SYMBOL_GPL(rds_atomic_send_complete);
 516
 517 /*
 518  * This is the same as rds_rdma_send_complete except we
 519  * don't do any locking - we have all the ingredients (message,
 520  * socket, socket lock) and can just move the notifier.
 521  */
 522 static inline void
 523 __rds_send_complete(struct rds_sock *rs, struct rds_message *rm, int status)
 524 {
 525         struct rm_rdma_op *ro;
 526         struct rm_atomic_op *ao;
 527
 528         ro = &rm->rdma;
 529         if (ro->op_active && ro->op_notify && ro->op_notifier) {
 530                 ro->op_notifier->n_status = status;
 531                 list_add_tail(&ro->op_notifier->n_list, &rs->rs_notify_queue);
 532                 ro->op_notifier = NULL;
 533         }
 534
 535         ao = &rm->atomic;
 536         if (ao->op_active && ao->op_notify && ao->op_notifier) {
 537                 ao->op_notifier->n_status = status;
 538                 list_add_tail(&ao->op_notifier->n_list, &rs->rs_notify_queue);
 539                 ao->op_notifier = NULL;
 540         }
 541
 542         /* No need to wake the app - caller does this */
 543 }
 544
 545 /*
 546  * This is called from the IB send completion when we detect
 547  * a RDMA operation that failed with remote access error.
 548  * So speed is not an issue here.
 549  */
 550 struct rds_message *rds_send_get_message(struct rds_connection *conn,
 551                                          struct rm_rdma_op *op)
 552 {
 553         struct rds_message *rm, *tmp, *found = NULL;
 554         unsigned long flags;
 555
 556         spin_lock_irqsave(&conn->c_lock, flags);
 557
 558         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
 559                 if (&rm->rdma == op) {
 560                         atomic_inc(&rm->m_refcount);
 561                         found = rm;
 562                         goto out;
 563                 }
 564         }
 565
 566         list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
 567                 if (&rm->rdma == op) {
 568                         atomic_inc(&rm->m_refcount);
 569                         found = rm;
 570                         break;
 571                 }
 572         }
 573
 574 out:
 575         spin_unlock_irqrestore(&conn->c_lock, flags);
 576
 577         return found;
 578 }
 579 EXPORT_SYMBOL_GPL(rds_send_get_message);
 580
 581 /*
 582  * This removes messages from the socket's list if they're on it.  The list
 583  * argument must be private to the caller, we must be able to modify it
 584  * without locks.  The messages must have a reference held for their
 585  * position on the list.  This function will drop that reference after
 586  * removing the messages from the 'messages' list regardless of if it found
 587  * the messages on the socket list or not.
 588  */
 589 void rds_send_remove_from_sock(struct list_head *messages, int status)
 590 {
 591         unsigned long flags;
 592         struct rds_sock *rs = NULL;
 593         struct rds_message *rm;
 594
 595         while (!list_empty(messages)) {
 596                 int was_on_sock = 0;
 597
 598                 rm = list_entry(messages->next, struct rds_message,
 599                                 m_conn_item);
 600                 list_del_init(&rm->m_conn_item);
 601
 602                 /*
 603                  * If we see this flag cleared then we're *sure* that someone
 604                  * else beat us to removing it from the sock.  If we race
 605                  * with their flag update we'll get the lock and then really
 606                  * see that the flag has been cleared.
 607                  *
 608                  * The message spinlock makes sure nobody clears rm->m_rs
 609                  * while we're messing with it. It does not prevent the
 610                  * message from being removed from the socket, though.
 611                  */
 612                 spin_lock_irqsave(&rm->m_rs_lock, flags);
 613                 if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags))
 614                         goto unlock_and_drop;
 615
 616                 if (rs != rm->m_rs) {
 617                         if (rs) {
 618                                 rds_wake_sk_sleep(rs);
 619                                 sock_put(rds_rs_to_sk(rs));
 620                         }
 621                         rs = rm->m_rs;
 622                         sock_hold(rds_rs_to_sk(rs));
 623                 }
 624                 spin_lock(&rs->rs_lock);
 625
 626                 if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) {
 627                         struct rm_rdma_op *ro = &rm->rdma;
 628                         struct rds_notifier *notifier;
 629
 630                         list_del_init(&rm->m_sock_item);
 631                         rds_send_sndbuf_remove(rs, rm);
 632
 633                         if (ro->op_active && ro->op_notifier &&
 634                                (ro->op_notify || (ro->op_recverr && status))) {
 635                                 notifier = ro->op_notifier;
 636                                 list_add_tail(&notifier->n_list,
 637                                                 &rs->rs_notify_queue);
 638                                 if (!notifier->n_status)
 639                                         notifier->n_status = status;
 640                                 rm->rdma.op_notifier = NULL;
 641                         }
 642                         was_on_sock = 1;
 643                         rm->m_rs = NULL;
 644                 }
 645                 spin_unlock(&rs->rs_lock);
 646
 647 unlock_and_drop:
 648                 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 649                 rds_message_put(rm);
 650                 if (was_on_sock)
 651                         rds_message_put(rm);
 652         }
 653
 654         if (rs) {
 655                 rds_wake_sk_sleep(rs);
 656                 sock_put(rds_rs_to_sk(rs));
 657         }
 658 }
 659
 660 /*
 661  * Transports call here when they've determined that the receiver queued
 662  * messages up to, and including, the given sequence number.  Messages are
 663  * moved to the retrans queue when rds_send_xmit picks them off the send
 664  * queue. This means that in the TCP case, the message may not have been
 665  * assigned the m_ack_seq yet - but that's fine as long as tcp_is_acked
 666  * checks the RDS_MSG_HAS_ACK_SEQ bit.
 667  *
 668  * XXX It's not clear to me how this is safely serialized with socket
 669  * destruction.  Maybe it should bail if it sees SOCK_DEAD.
 670  */
 671 void rds_send_drop_acked(struct rds_connection *conn, u64 ack,
 672                          is_acked_func is_acked)
 673 {
 674         struct rds_message *rm, *tmp;
 675         unsigned long flags;
 676         LIST_HEAD(list);
 677
 678         spin_lock_irqsave(&conn->c_lock, flags);
 679
 680         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
 681                 if (!rds_send_is_acked(rm, ack, is_acked))
 682                         break;
 683
 684                 list_move(&rm->m_conn_item, &list);
 685                 clear_bit(RDS_MSG_ON_CONN, &rm->m_flags);
 686         }
 687
 688         /* order flag updates with spin locks */
 689         if (!list_empty(&list))
 690                 smp_mb__after_clear_bit();
 691
 692         spin_unlock_irqrestore(&conn->c_lock, flags);
 693
 694         /* now remove the messages from the sock list as needed */
 695         rds_send_remove_from_sock(&list, RDS_RDMA_SUCCESS);
 696 }
 697 EXPORT_SYMBOL_GPL(rds_send_drop_acked);
 698
 699 void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest)
 700 {
 701         struct rds_message *rm, *tmp;
 702         struct rds_connection *conn;
 703         unsigned long flags;
 704         LIST_HEAD(list);
 705
 706         /* get all the messages we're dropping under the rs lock */
 707         spin_lock_irqsave(&rs->rs_lock, flags);
 708
 709         list_for_each_entry_safe(rm, tmp, &rs->rs_send_queue, m_sock_item) {
 710                 if (dest && (dest->sin_addr.s_addr != rm->m_daddr ||
 711                              dest->sin_port != rm->m_inc.i_hdr.h_dport))
 712                         continue;
 713
 714                 list_move(&rm->m_sock_item, &list);
 715                 rds_send_sndbuf_remove(rs, rm);
 716                 clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
 717         }
 718
 719         /* order flag updates with the rs lock */
 720         smp_mb__after_clear_bit();
 721
 722         spin_unlock_irqrestore(&rs->rs_lock, flags);
 723
 724         if (list_empty(&list))
 725                 return;
 726
 727         /* Remove the messages from the conn */
 728         list_for_each_entry(rm, &list, m_sock_item) {
 729
 730                 conn = rm->m_inc.i_conn;
 731
 732                 spin_lock_irqsave(&conn->c_lock, flags);
 733                 /*
 734                  * Maybe someone else beat us to removing rm from the conn.
 735                  * If we race with their flag update we'll get the lock and
 736                  * then really see that the flag has been cleared.
 737                  */
 738                 if (!test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) {
 739                         spin_unlock_irqrestore(&conn->c_lock, flags);
 740                         continue;
 741                 }
 742                 list_del_init(&rm->m_conn_item);
 743                 spin_unlock_irqrestore(&conn->c_lock, flags);
 744
 745                 /*
 746                  * Couldn't grab m_rs_lock in top loop (lock ordering),
 747                  * but we can now.
 748                  */
 749                 spin_lock_irqsave(&rm->m_rs_lock, flags);
 750
 751                 spin_lock(&rs->rs_lock);
 752                 __rds_send_complete(rs, rm, RDS_RDMA_CANCELED);
 753                 spin_unlock(&rs->rs_lock);
 754
 755                 rm->m_rs = NULL;
 756                 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 757
 758                 rds_message_put(rm);
 759         }
 760
 761         rds_wake_sk_sleep(rs);
 762
 763         while (!list_empty(&list)) {
 764                 rm = list_entry(list.next, struct rds_message, m_sock_item);
 765                 list_del_init(&rm->m_sock_item);
 766
 767                 rds_message_wait(rm);
 768                 rds_message_put(rm);
 769         }
 770 }
 771
 772 /*
 773  * we only want this to fire once so we use the callers 'queued'.  It's
 774  * possible that another thread can race with us and remove the
 775  * message from the flow with RDS_CANCEL_SENT_TO.
 776  */
 777 static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn,
 778                              struct rds_message *rm, __be16 sport,
 779                              __be16 dport, int *queued)
 780 {
 781         unsigned long flags;
 782         u32 len;
 783
 784         if (*queued)
 785                 goto out;
 786
 787         len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
 788
 789         /* this is the only place which holds both the socket's rs_lock
 790          * and the connection's c_lock */
 791         spin_lock_irqsave(&rs->rs_lock, flags);
 792
 793         /*
 794          * If there is a little space in sndbuf, we don't queue anything,
 795          * and userspace gets -EAGAIN. But poll() indicates there's send
 796          * room. This can lead to bad behavior (spinning) if snd_bytes isn't
 797          * freed up by incoming acks. So we check the *old* value of
 798          * rs_snd_bytes here to allow the last msg to exceed the buffer,
 799          * and poll() now knows no more data can be sent.
 800          */
 801         if (rs->rs_snd_bytes < rds_sk_sndbuf(rs)) {
 802                 rs->rs_snd_bytes += len;
 803
 804                 /* let recv side know we are close to send space exhaustion.
 805                  * This is probably not the optimal way to do it, as this
 806                  * means we set the flag on *all* messages as soon as our
 807                  * throughput hits a certain threshold.
 808                  */
 809                 if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2)
 810                         __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
 811
 812                 list_add_tail(&rm->m_sock_item, &rs->rs_send_queue);
 813                 set_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
 814                 rds_message_addref(rm);
 815                 rm->m_rs = rs;
 816
 817                 /* The code ordering is a little weird, but we're
 818                    trying to minimize the time we hold c_lock */
 819                 rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport, 0);
 820                 rm->m_inc.i_conn = conn;
 821                 rds_message_addref(rm);
 822
 823                 spin_lock(&conn->c_lock);
 824                 rm->m_inc.i_hdr.h_sequence = cpu_to_be64(conn->c_next_tx_seq++);
 825                 list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
 826                 set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
 827                 spin_unlock(&conn->c_lock);
 828
 829                 rdsdebug("queued msg %p len %d, rs %p bytes %d seq %llu\n",
 830                          rm, len, rs, rs->rs_snd_bytes,
 831                          (unsigned long long)be64_to_cpu(rm->m_inc.i_hdr.h_sequence));
 832
 833                 *queued = 1;
 834         }
 835
 836         spin_unlock_irqrestore(&rs->rs_lock, flags);
 837 out:
 838         return *queued;
 839 }
 840
 841 /*
 842  * rds_message is getting to be quite complicated, and we'd like to allocate
 843  * it all in one go. This figures out how big it needs to be up front.
 844  */
 845 static int rds_rm_size(struct msghdr *msg, int data_len)
 846 {
 847         struct cmsghdr *cmsg;
 848         int size = 0;
 849         int cmsg_groups = 0;
 850         int retval;
 851
 852         for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
 853                 if (!CMSG_OK(msg, cmsg))
 854                         return -EINVAL;
 855
 856                 if (cmsg->cmsg_level != SOL_RDS)
 857                         continue;
 858
 859                 switch (cmsg->cmsg_type) {
 860                 case RDS_CMSG_RDMA_ARGS:
 861                         cmsg_groups |= 1;
 862                         retval = rds_rdma_extra_size(CMSG_DATA(cmsg));
 863                         if (retval < 0)
 864                                 return retval;
 865                         size += retval;
 866
 867                         break;
 868
 869                 case RDS_CMSG_RDMA_DEST:
 870                 case RDS_CMSG_RDMA_MAP:
 871                         cmsg_groups |= 2;
 872                         /* these are valid but do no add any size */
 873                         break;
 874
 875                 case RDS_CMSG_ATOMIC_CSWP:
 876                 case RDS_CMSG_ATOMIC_FADD:
 877                         cmsg_groups |= 1;
 878                         size += sizeof(struct scatterlist);
 879                         break;
 880
 881                 default:
 882                         return -EINVAL;
 883                 }
 884
 885         }
 886
 887         size += ceil(data_len, PAGE_SIZE) * sizeof(struct scatterlist);
 888
 889         /* Ensure (DEST, MAP) are never used with (ARGS, ATOMIC) */
 890         if (cmsg_groups == 3)
 891                 return -EINVAL;
 892
 893         return size;
 894 }
 895
 896 static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
 897                          struct msghdr *msg, int *allocated_mr)
 898 {
 899         struct cmsghdr *cmsg;
 900         int ret = 0;
 901
 902         for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
 903                 if (!CMSG_OK(msg, cmsg))
 904                         return -EINVAL;
 905
 906                 if (cmsg->cmsg_level != SOL_RDS)
 907                         continue;
 908
 909                 /* As a side effect, RDMA_DEST and RDMA_MAP will set
 910                  * rm->rdma.m_rdma_cookie and rm->rdma.m_rdma_mr.
 911                  */
 912                 switch (cmsg->cmsg_type) {
 913                 case RDS_CMSG_RDMA_ARGS:
 914                         ret = rds_cmsg_rdma_args(rs, rm, cmsg);
 915                         break;
 916
 917                 case RDS_CMSG_RDMA_DEST:
 918                         ret = rds_cmsg_rdma_dest(rs, rm, cmsg);
 919                         break;
 920
 921                 case RDS_CMSG_RDMA_MAP:
 922                         ret = rds_cmsg_rdma_map(rs, rm, cmsg);
 923                         if (!ret)
 924                                 *allocated_mr = 1;
 925                         break;
 926                 case RDS_CMSG_ATOMIC_CSWP:
 927                 case RDS_CMSG_ATOMIC_FADD:
 928                         ret = rds_cmsg_atomic(rs, rm, cmsg);
 929                         break;
 930
 931                 default:
 932                         return -EINVAL;
 933                 }
 934
 935                 if (ret)
 936                         break;
 937         }
 938
 939         return ret;
 940 }
 941
 942 int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
 943                 size_t payload_len)
 944 {
 945         struct sock *sk = sock->sk;
 946         struct rds_sock *rs = rds_sk_to_rs(sk);
 947         struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name;
 948         __be32 daddr;
 949         __be16 dport;
 950         struct rds_message *rm = NULL;
 951         struct rds_connection *conn;
 952         int ret = 0;
 953         int queued = 0, allocated_mr = 0;
 954         int nonblock = msg->msg_flags & MSG_DONTWAIT;
 955         long timeo = sock_sndtimeo(sk, nonblock);
 956
 957         /* Mirror Linux UDP mirror of BSD error message compatibility */
 958         /* XXX: Perhaps MSG_MORE someday */
 959         if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) {
 960                 printk(KERN_INFO "msg_flags 0x%08X\n", msg->msg_flags);
 961                 ret = -EOPNOTSUPP;
 962                 goto out;
 963         }
 964
 965         if (msg->msg_namelen) {
 966                 /* XXX fail non-unicast destination IPs? */
 967                 if (msg->msg_namelen < sizeof(*usin) || usin->sin_family != AF_INET) {
 968                         ret = -EINVAL;
 969                         goto out;
 970                 }
 971                 daddr = usin->sin_addr.s_addr;
 972                 dport = usin->sin_port;
 973         } else {
 974                 /* We only care about consistency with ->connect() */
 975                 lock_sock(sk);
 976                 daddr = rs->rs_conn_addr;
 977                 dport = rs->rs_conn_port;
 978                 release_sock(sk);
 979         }
 980
 981         /* racing with another thread binding seems ok here */
 982         if (daddr == 0 || rs->rs_bound_addr == 0) {
 983                 ret = -ENOTCONN; /* XXX not a great errno */
 984                 goto out;
 985         }
 986
 987         /* size of rm including all sgs */
 988         ret = rds_rm_size(msg, payload_len);
 989         if (ret < 0)
 990                 goto out;
 991
 992         rm = rds_message_alloc(ret, GFP_KERNEL);
 993         if (!rm) {
 994                 ret = -ENOMEM;
 995                 goto out;
 996         }
 997
 998         /* Attach data to the rm */
 999         if (payload_len) {
1000                 rm->data.op_sg = rds_message_alloc_sgs(rm, ceil(payload_len, PAGE_SIZE));
1001                 ret = rds_message_copy_from_user(rm, msg->msg_iov, payload_len);
1002                 if (ret)
1003                         goto out;
1004         }
1005         rm->data.op_active = 1;
1006
1007         rm->m_daddr = daddr;
1008
1009         /* rds_conn_create has a spinlock that runs with IRQ off.
1010          * Caching the conn in the socket helps a lot. */
1011         if (rs->rs_conn && rs->rs_conn->c_faddr == daddr)
1012                 conn = rs->rs_conn;
1013         else {
1014                 conn = rds_conn_create_outgoing(rs->rs_bound_addr, daddr,
1015                                         rs->rs_transport,
1016                                         sock->sk->sk_allocation);
1017                 if (IS_ERR(conn)) {
1018                         ret = PTR_ERR(conn);
1019                         goto out;
1020                 }
1021                 rs->rs_conn = conn;
1022         }
1023
1024         /* Parse any control messages the user may have included. */
1025         ret = rds_cmsg_send(rs, rm, msg, &allocated_mr);
1026         if (ret)
1027                 goto out;
1028
1029         if (rm->rdma.op_active && !conn->c_trans->xmit_rdma) {
1030                 if (printk_ratelimit())
1031                         printk(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",
1032                                &rm->rdma, conn->c_trans->xmit_rdma);
1033                 ret = -EOPNOTSUPP;
1034                 goto out;
1035         }
1036
1037         if (rm->atomic.op_active && !conn->c_trans->xmit_atomic) {
1038                 if (printk_ratelimit())
1039                         printk(KERN_NOTICE "atomic_op %p conn xmit_atomic %p\n",
1040                                &rm->atomic, conn->c_trans->xmit_atomic);
1041                 ret = -EOPNOTSUPP;
1042                 goto out;
1043         }
1044
1045         /* If the connection is down, trigger a connect. We may
1046          * have scheduled a delayed reconnect however - in this case
1047          * we should not interfere.
1048          */
1049         if (rds_conn_state(conn) == RDS_CONN_DOWN &&
1050             !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
1051                 queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
1052
1053         ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);
1054         if (ret) {
1055                 rs->rs_seen_congestion = 1;
1056                 goto out;
1057         }
1058
1059         while (!rds_send_queue_rm(rs, conn, rm, rs->rs_bound_port,
1060                                   dport, &queued)) {
1061                 rds_stats_inc(s_send_queue_full);
1062                 /* XXX make sure this is reasonable */
1063                 if (payload_len > rds_sk_sndbuf(rs)) {
1064                         ret = -EMSGSIZE;
1065                         goto out;
1066                 }
1067                 if (nonblock) {
1068                         ret = -EAGAIN;
1069                         goto out;
1070                 }
1071
1072                 timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
1073                                         rds_send_queue_rm(rs, conn, rm,
1074                                                           rs->rs_bound_port,
1075                                                           dport,
1076                                                           &queued),
1077                                         timeo);
1078                 rdsdebug("sendmsg woke queued %d timeo %ld\n", queued, timeo);
1079                 if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
1080                         continue;
1081
1082                 ret = timeo;
1083                 if (ret == 0)
1084                         ret = -ETIMEDOUT;
1085                 goto out;
1086         }
1087
1088         /*
1089          * By now we've committed to the send.  We reuse rds_send_worker()
1090          * to retry sends in the rds thread if the transport asks us to.
1091          */
1092         rds_stats_inc(s_send_queued);
1093
1094         if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
1095                 rds_send_xmit(conn);
1096
1097         rds_message_put(rm);
1098         return payload_len;
1099
1100 out:
1101         /* If the user included a RDMA_MAP cmsg, we allocated a MR on the fly.
1102          * If the sendmsg goes through, we keep the MR. If it fails with EAGAIN
1103          * or in any other way, we need to destroy the MR again */
1104         if (allocated_mr)
1105                 rds_rdma_unuse(rs, rds_rdma_cookie_key(rm->m_rdma_cookie), 1);
1106
1107         if (rm)
1108                 rds_message_put(rm);
1109         return ret;
1110 }
1111
1112 /*
1113  * Reply to a ping packet.
1114  */
1115 int
1116 rds_send_pong(struct rds_connection *conn, __be16 dport)
1117 {
1118         struct rds_message *rm;
1119         unsigned long flags;
1120         int ret = 0;
1121
1122         rm = rds_message_alloc(0, GFP_ATOMIC);
1123         if (!rm) {
1124                 ret = -ENOMEM;
1125                 goto out;
1126         }
1127
1128         rm->m_daddr = conn->c_faddr;
1129         rm->data.op_active = 1;
1130
1131         /* If the connection is down, trigger a connect. We may
1132          * have scheduled a delayed reconnect however - in this case
1133          * we should not interfere.
1134          */
1135         if (rds_conn_state(conn) == RDS_CONN_DOWN &&
1136             !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
1137                 queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
1138
1139         ret = rds_cong_wait(conn->c_fcong, dport, 1, NULL);
1140         if (ret)
1141                 goto out;
1142
1143         spin_lock_irqsave(&conn->c_lock, flags);
1144         list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
1145         set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
1146         rds_message_addref(rm);
1147         rm->m_inc.i_conn = conn;
1148
1149         rds_message_populate_header(&rm->m_inc.i_hdr, 0, dport,
1150                                     conn->c_next_tx_seq);
1151         conn->c_next_tx_seq++;
1152         spin_unlock_irqrestore(&conn->c_lock, flags);
1153
1154         rds_stats_inc(s_send_queued);
1155         rds_stats_inc(s_send_pong);
1156
1157         if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
1158                 rds_send_xmit(conn);
1159
1160         rds_message_put(rm);
1161         return 0;
1162
1163 out:
1164         if (rm)
1165                 rds_message_put(rm);
1166         return ret;
1167 }