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 printk(KERN_CRIT "send reset unmapping %p\n", rm);
  72                 rds_message_unmapped(rm);
  73                 spin_unlock_irqrestore(&conn->c_send_lock, flags);
  74
  75                 rds_message_put(rm);
  76         } else {
  77                 spin_unlock_irqrestore(&conn->c_send_lock, flags);
  78         }
  79
  80         conn->c_xmit_sg = 0;
  81         conn->c_xmit_hdr_off = 0;
  82         conn->c_xmit_data_off = 0;
  83         conn->c_xmit_atomic_sent = 0;
  84         conn->c_xmit_rdma_sent = 0;
  85         conn->c_xmit_data_sent = 0;
  86
  87         conn->c_map_queued = 0;
  88
  89         conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
  90         conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
  91
  92         /* Mark messages as retransmissions, and move them to the send q */
  93         spin_lock_irqsave(&conn->c_lock, flags);
  94         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
  95                 set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
  96                 set_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags);
  97         }
  98         list_splice_init(&conn->c_retrans, &conn->c_send_queue);
  99         spin_unlock_irqrestore(&conn->c_lock, flags);
 100 }
 101
 102 /*
 103  * We're making the concious trade-off here to only send one message
 104  * down the connection at a time.
 105  *   Pro:
 106  *      - tx queueing is a simple fifo list
 107  *      - reassembly is optional and easily done by transports per conn
 108  *      - no per flow rx lookup at all, straight to the socket
 109  *      - less per-frag memory and wire overhead
 110  *   Con:
 111  *      - queued acks can be delayed behind large messages
 112  *   Depends:
 113  *      - small message latency is higher behind queued large messages
 114  *      - large message latency isn't starved by intervening small sends
 115  */
 116 int rds_send_xmit(struct rds_connection *conn)
 117 {
 118         struct rds_message *rm;
 119         unsigned long flags;
 120         unsigned int tmp;
 121         struct scatterlist *sg;
 122         int ret = 0;
 123         int gen = 0;
 124         LIST_HEAD(to_be_dropped);
 125
 126 restart:
 127         if (!rds_conn_up(conn))
 128                 goto out;
 129
 130         /*
 131          * sendmsg calls here after having queued its message on the send
 132          * queue.  We only have one task feeding the connection at a time.  If
 133          * another thread is already feeding the queue then we back off.  This
 134          * avoids blocking the caller and trading per-connection data between
 135          * caches per message.
 136          */
 137         if (!spin_trylock_irqsave(&conn->c_send_lock, flags)) {
 138                 rds_stats_inc(s_send_lock_contention);
 139                 ret = -ENOMEM;
 140                 goto out;
 141         }
 142         atomic_inc(&conn->c_senders);
 143
 144         if (conn->c_trans->xmit_prepare)
 145                 conn->c_trans->xmit_prepare(conn);
 146
 147         gen = atomic_inc_return(&conn->c_send_generation);
 148
 149         /*
 150          * spin trying to push headers and data down the connection until
 151          * the connection doesn't make forward progress.
 152          */
 153         while (1) {
 154
 155                 rm = conn->c_xmit_rm;
 156
 157                 /*
 158                  * If between sending messages, we can send a pending congestion
 159                  * map update.
 160                  */
 161                 if (!rm && test_and_clear_bit(0, &conn->c_map_queued)) {
 162                         rm = rds_cong_update_alloc(conn);
 163                         if (IS_ERR(rm)) {
 164                                 ret = PTR_ERR(rm);
 165                                 break;
 166                         }
 167                         rm->data.op_active = 1;
 168
 169                         conn->c_xmit_rm = rm;
 170                 }
 171
 172                 /*
 173                  * If not already working on one, grab the next message.
 174                  *
 175                  * c_xmit_rm holds a ref while we're sending this message down
 176                  * the connction.  We can use this ref while holding the
 177                  * send_sem.. rds_send_reset() is serialized with it.
 178                  */
 179                 if (!rm) {
 180                         unsigned int len;
 181
 182                         spin_lock(&conn->c_lock);
 183
 184                         if (!list_empty(&conn->c_send_queue)) {
 185                                 rm = list_entry(conn->c_send_queue.next,
 186                                                 struct rds_message,
 187                                                 m_conn_item);
 188                                 rds_message_addref(rm);
 189
 190                                 /*
 191                                  * Move the message from the send queue to the retransmit
 192                                  * list right away.
 193                                  */
 194                                 list_move_tail(&rm->m_conn_item, &conn->c_retrans);
 195                         }
 196
 197                         spin_unlock(&conn->c_lock);
 198
 199                         if (!rm)
 200                                 break;
 201
 202                         /* Unfortunately, the way Infiniband deals with
 203                          * RDMA to a bad MR key is by moving the entire
 204                          * queue pair to error state. We cold possibly
 205                          * recover from that, but right now we drop the
 206                          * connection.
 207                          * Therefore, we never retransmit messages with RDMA ops.
 208                          */
 209                         if (rm->rdma.op_active &&
 210                             test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) {
 211                                 spin_lock(&conn->c_lock);
 212                                 if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags))
 213                                         list_move(&rm->m_conn_item, &to_be_dropped);
 214                                 spin_unlock(&conn->c_lock);
 215                                 continue;
 216                         }
 217
 218                         /* Require an ACK every once in a while */
 219                         len = ntohl(rm->m_inc.i_hdr.h_len);
 220                         if (conn->c_unacked_packets == 0 ||
 221                             conn->c_unacked_bytes < len) {
 222                                 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
 223
 224                                 conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
 225                                 conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
 226                                 rds_stats_inc(s_send_ack_required);
 227                         } else {
 228                                 conn->c_unacked_bytes -= len;
 229                                 conn->c_unacked_packets--;
 230                         }
 231
 232                         conn->c_xmit_rm = rm;
 233                 }
 234
 235                 /* The transport either sends the whole rdma or none of it */
 236                 if (rm->rdma.op_active && !conn->c_xmit_rdma_sent) {
 237                         rm->m_final_op = &rm->rdma;
 238                         ret = conn->c_trans->xmit_rdma(conn, &rm->rdma);
 239                         if (ret)
 240                                 break;
 241                         conn->c_xmit_rdma_sent = 1;
 242
 243                         /* The transport owns the mapped memory for now.
 244                          * You can't unmap it while it's on the send queue */
 245                         set_bit(RDS_MSG_MAPPED, &rm->m_flags);
 246                 }
 247
 248                 if (rm->atomic.op_active && !conn->c_xmit_atomic_sent) {
 249                         rm->m_final_op = &rm->atomic;
 250                         ret = conn->c_trans->xmit_atomic(conn, &rm->atomic);
 251                         if (ret)
 252                                 break;
 253                         conn->c_xmit_atomic_sent = 1;
 254
 255                         /* The transport owns the mapped memory for now.
 256                          * You can't unmap it while it's on the send queue */
 257                         set_bit(RDS_MSG_MAPPED, &rm->m_flags);
 258                 }
 259
 260                 /*
 261                  * A number of cases require an RDS header to be sent
 262                  * even if there is no data.
 263                  * We permit 0-byte sends; rds-ping depends on this.
 264                  * However, if there are exclusively attached silent ops,
 265                  * we skip the hdr/data send, to enable silent operation.
 266                  */
 267                 if (rm->data.op_nents == 0) {
 268                         int ops_present;
 269                         int all_ops_are_silent = 1;
 270
 271                         ops_present = (rm->atomic.op_active || rm->rdma.op_active);
 272                         if (rm->atomic.op_active && !rm->atomic.op_silent)
 273                                 all_ops_are_silent = 0;
 274                         if (rm->rdma.op_active && !rm->rdma.op_silent)
 275                                 all_ops_are_silent = 0;
 276
 277                         if (ops_present && all_ops_are_silent
 278                             && !rm->m_rdma_cookie)
 279                                 rm->data.op_active = 0;
 280                 }
 281
 282                 if (rm->data.op_active && !conn->c_xmit_data_sent) {
 283                         rm->m_final_op = &rm->data;
 284                         ret = conn->c_trans->xmit(conn, rm,
 285                                                   conn->c_xmit_hdr_off,
 286                                                   conn->c_xmit_sg,
 287                                                   conn->c_xmit_data_off);
 288                         if (ret <= 0)
 289                                 break;
 290
 291                         if (conn->c_xmit_hdr_off < sizeof(struct rds_header)) {
 292                                 tmp = min_t(int, ret,
 293                                             sizeof(struct rds_header) -
 294                                             conn->c_xmit_hdr_off);
 295                                 conn->c_xmit_hdr_off += tmp;
 296                                 ret -= tmp;
 297                         }
 298
 299                         sg = &rm->data.op_sg[conn->c_xmit_sg];
 300                         while (ret) {
 301                                 tmp = min_t(int, ret, sg->length -
 302                                                       conn->c_xmit_data_off);
 303                                 conn->c_xmit_data_off += tmp;
 304                                 ret -= tmp;
 305                                 if (conn->c_xmit_data_off == sg->length) {
 306                                         conn->c_xmit_data_off = 0;
 307                                         sg++;
 308                                         conn->c_xmit_sg++;
 309                                         BUG_ON(ret != 0 &&
 310                                                conn->c_xmit_sg == rm->data.op_nents);
 311                                 }
 312                         }
 313
 314                         if (conn->c_xmit_hdr_off == sizeof(struct rds_header) &&
 315                             (conn->c_xmit_sg == rm->data.op_nents))
 316                                 conn->c_xmit_data_sent = 1;
 317                 }
 318
 319                 /*
 320                  * A rm will only take multiple times through this loop
 321                  * if there is a data op. Thus, if the data is sent (or there was
 322                  * none), then we're done with the rm.
 323                  */
 324                 if (!rm->data.op_active || conn->c_xmit_data_sent) {
 325                         conn->c_xmit_rm = NULL;
 326                         conn->c_xmit_sg = 0;
 327                         conn->c_xmit_hdr_off = 0;
 328                         conn->c_xmit_data_off = 0;
 329                         conn->c_xmit_rdma_sent = 0;
 330                         conn->c_xmit_atomic_sent = 0;
 331                         conn->c_xmit_data_sent = 0;
 332
 333                         rds_message_put(rm);
 334                 }
 335         }
 336
 337         if (conn->c_trans->xmit_complete)
 338                 conn->c_trans->xmit_complete(conn);
 339
 340         /*
 341          * We might be racing with another sender who queued a message but
 342          * backed off on noticing that we held the c_send_lock.  If we check
 343          * for queued messages after dropping the sem then either we'll
 344          * see the queued message or the queuer will get the sem.  If we
 345          * notice the queued message then we trigger an immediate retry.
 346          *
 347          * We need to be careful only to do this when we stopped processing
 348          * the send queue because it was empty.  It's the only way we
 349          * stop processing the loop when the transport hasn't taken
 350          * responsibility for forward progress.
 351          */
 352         spin_unlock_irqrestore(&conn->c_send_lock, flags);
 353
 354         /* Nuke any messages we decided not to retransmit. */
 355         if (!list_empty(&to_be_dropped)) {
 356                 /* irqs on here, so we can put(), unlike above */
 357                 list_for_each_entry(rm, &to_be_dropped, m_conn_item)
 358                         rds_message_put(rm);
 359                 rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED);
 360         }
 361
 362         atomic_dec(&conn->c_senders);
 363
 364         /*
 365          * Other senders will see we have c_send_lock and exit. We
 366          * need to recheck the send queue and race again for c_send_lock
 367          * to make sure messages don't just sit on the send queue, if
 368          * somebody hasn't already beat us into the loop.
 369          *
 370          * If the transport cannot continue (i.e ret != 0), then it must
 371          * call us when more room is available, such as from the tx
 372          * completion handler.
 373          */
 374         if (ret == 0) {
 375                 smp_mb();
 376                 if (!list_empty(&conn->c_send_queue)) {
 377                         rds_stats_inc(s_send_lock_queue_raced);
 378                         if (gen == atomic_read(&conn->c_send_generation)) {
 379                                 goto restart;
 380                         }
 381                 }
 382         }
 383 out:
 384         return ret;
 385 }
 386
 387 static void rds_send_sndbuf_remove(struct rds_sock *rs, struct rds_message *rm)
 388 {
 389         u32 len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
 390
 391         assert_spin_locked(&rs->rs_lock);
 392
 393         BUG_ON(rs->rs_snd_bytes < len);
 394         rs->rs_snd_bytes -= len;
 395
 396         if (rs->rs_snd_bytes == 0)
 397                 rds_stats_inc(s_send_queue_empty);
 398 }
 399
 400 static inline int rds_send_is_acked(struct rds_message *rm, u64 ack,
 401                                     is_acked_func is_acked)
 402 {
 403         if (is_acked)
 404                 return is_acked(rm, ack);
 405         return be64_to_cpu(rm->m_inc.i_hdr.h_sequence) <= ack;
 406 }
 407
 408 /*
 409  * Returns true if there are no messages on the send and retransmit queues
 410  * which have a sequence number greater than or equal to the given sequence
 411  * number.
 412  */
 413 int rds_send_acked_before(struct rds_connection *conn, u64 seq)
 414 {
 415         struct rds_message *rm, *tmp;
 416         int ret = 1;
 417
 418         spin_lock(&conn->c_lock);
 419
 420         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
 421                 if (be64_to_cpu(rm->m_inc.i_hdr.h_sequence) < seq)
 422                         ret = 0;
 423                 break;
 424         }
 425
 426         list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
 427                 if (be64_to_cpu(rm->m_inc.i_hdr.h_sequence) < seq)
 428                         ret = 0;
 429                 break;
 430         }
 431
 432         spin_unlock(&conn->c_lock);
 433
 434         return ret;
 435 }
 436
 437 /*
 438  * This is pretty similar to what happens below in the ACK
 439  * handling code - except that we call here as soon as we get
 440  * the IB send completion on the RDMA op and the accompanying
 441  * message.
 442  */
 443 void rds_rdma_send_complete(struct rds_message *rm, int status)
 444 {
 445         struct rds_sock *rs = NULL;
 446         struct rm_rdma_op *ro;
 447         struct rds_notifier *notifier;
 448         unsigned long flags;
 449
 450         spin_lock_irqsave(&rm->m_rs_lock, flags);
 451
 452         ro = &rm->rdma;
 453         if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) &&
 454             ro->op_active && ro->op_notify && ro->op_notifier) {
 455                 notifier = ro->op_notifier;
 456                 rs = rm->m_rs;
 457                 sock_hold(rds_rs_to_sk(rs));
 458
 459                 notifier->n_status = status;
 460                 spin_lock(&rs->rs_lock);
 461                 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
 462                 spin_unlock(&rs->rs_lock);
 463
 464                 ro->op_notifier = NULL;
 465         }
 466
 467         spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 468
 469         if (rs) {
 470                 rds_wake_sk_sleep(rs);
 471                 sock_put(rds_rs_to_sk(rs));
 472         }
 473 }
 474 EXPORT_SYMBOL_GPL(rds_rdma_send_complete);
 475
 476 /*
 477  * Just like above, except looks at atomic op
 478  */
 479 void rds_atomic_send_complete(struct rds_message *rm, int status)
 480 {
 481         struct rds_sock *rs = NULL;
 482         struct rm_atomic_op *ao;
 483         struct rds_notifier *notifier;
 484         unsigned long flags;
 485
 486         spin_lock_irqsave(&rm->m_rs_lock, flags);
 487
 488         ao = &rm->atomic;
 489         if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags)
 490             && ao->op_active && ao->op_notify && ao->op_notifier) {
 491                 notifier = ao->op_notifier;
 492                 rs = rm->m_rs;
 493                 sock_hold(rds_rs_to_sk(rs));
 494
 495                 notifier->n_status = status;
 496                 spin_lock(&rs->rs_lock);
 497                 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
 498                 spin_unlock(&rs->rs_lock);
 499
 500                 ao->op_notifier = NULL;
 501         }
 502
 503         spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 504
 505         if (rs) {
 506                 rds_wake_sk_sleep(rs);
 507                 sock_put(rds_rs_to_sk(rs));
 508         }
 509 }
 510 EXPORT_SYMBOL_GPL(rds_atomic_send_complete);
 511
 512 /*
 513  * This is the same as rds_rdma_send_complete except we
 514  * don't do any locking - we have all the ingredients (message,
 515  * socket, socket lock) and can just move the notifier.
 516  */
 517 static inline void
 518 __rds_send_complete(struct rds_sock *rs, struct rds_message *rm, int status)
 519 {
 520         struct rm_rdma_op *ro;
 521         struct rm_atomic_op *ao;
 522
 523         ro = &rm->rdma;
 524         if (ro->op_active && ro->op_notify && ro->op_notifier) {
 525                 ro->op_notifier->n_status = status;
 526                 list_add_tail(&ro->op_notifier->n_list, &rs->rs_notify_queue);
 527                 ro->op_notifier = NULL;
 528         }
 529
 530         ao = &rm->atomic;
 531         if (ao->op_active && ao->op_notify && ao->op_notifier) {
 532                 ao->op_notifier->n_status = status;
 533                 list_add_tail(&ao->op_notifier->n_list, &rs->rs_notify_queue);
 534                 ao->op_notifier = NULL;
 535         }
 536
 537         /* No need to wake the app - caller does this */
 538 }
 539
 540 /*
 541  * This is called from the IB send completion when we detect
 542  * a RDMA operation that failed with remote access error.
 543  * So speed is not an issue here.
 544  */
 545 struct rds_message *rds_send_get_message(struct rds_connection *conn,
 546                                          struct rm_rdma_op *op)
 547 {
 548         struct rds_message *rm, *tmp, *found = NULL;
 549         unsigned long flags;
 550
 551         spin_lock_irqsave(&conn->c_lock, flags);
 552
 553         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
 554                 if (&rm->rdma == op) {
 555                         atomic_inc(&rm->m_refcount);
 556                         found = rm;
 557                         goto out;
 558                 }
 559         }
 560
 561         list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
 562                 if (&rm->rdma == op) {
 563                         atomic_inc(&rm->m_refcount);
 564                         found = rm;
 565                         break;
 566                 }
 567         }
 568
 569 out:
 570         spin_unlock_irqrestore(&conn->c_lock, flags);
 571
 572         return found;
 573 }
 574 EXPORT_SYMBOL_GPL(rds_send_get_message);
 575
 576 /*
 577  * This removes messages from the socket's list if they're on it.  The list
 578  * argument must be private to the caller, we must be able to modify it
 579  * without locks.  The messages must have a reference held for their
 580  * position on the list.  This function will drop that reference after
 581  * removing the messages from the 'messages' list regardless of if it found
 582  * the messages on the socket list or not.
 583  */
 584 void rds_send_remove_from_sock(struct list_head *messages, int status)
 585 {
 586         unsigned long flags;
 587         struct rds_sock *rs = NULL;
 588         struct rds_message *rm;
 589
 590         while (!list_empty(messages)) {
 591                 int was_on_sock = 0;
 592
 593                 rm = list_entry(messages->next, struct rds_message,
 594                                 m_conn_item);
 595                 list_del_init(&rm->m_conn_item);
 596
 597                 /*
 598                  * If we see this flag cleared then we're *sure* that someone
 599                  * else beat us to removing it from the sock.  If we race
 600                  * with their flag update we'll get the lock and then really
 601                  * see that the flag has been cleared.
 602                  *
 603                  * The message spinlock makes sure nobody clears rm->m_rs
 604                  * while we're messing with it. It does not prevent the
 605                  * message from being removed from the socket, though.
 606                  */
 607                 spin_lock_irqsave(&rm->m_rs_lock, flags);
 608                 if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags))
 609                         goto unlock_and_drop;
 610
 611                 if (rs != rm->m_rs) {
 612                         if (rs) {
 613                                 rds_wake_sk_sleep(rs);
 614                                 sock_put(rds_rs_to_sk(rs));
 615                         }
 616                         rs = rm->m_rs;
 617                         sock_hold(rds_rs_to_sk(rs));
 618                 }
 619                 spin_lock(&rs->rs_lock);
 620
 621                 if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) {
 622                         struct rm_rdma_op *ro = &rm->rdma;
 623                         struct rds_notifier *notifier;
 624
 625                         list_del_init(&rm->m_sock_item);
 626                         rds_send_sndbuf_remove(rs, rm);
 627
 628                         if (ro->op_active && ro->op_notifier &&
 629                                (ro->op_notify || (ro->op_recverr && status))) {
 630                                 notifier = ro->op_notifier;
 631                                 list_add_tail(&notifier->n_list,
 632                                                 &rs->rs_notify_queue);
 633                                 if (!notifier->n_status)
 634                                         notifier->n_status = status;
 635                                 rm->rdma.op_notifier = NULL;
 636                         }
 637                         was_on_sock = 1;
 638                         rm->m_rs = NULL;
 639                 }
 640                 spin_unlock(&rs->rs_lock);
 641
 642 unlock_and_drop:
 643                 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 644                 rds_message_put(rm);
 645                 if (was_on_sock)
 646                         rds_message_put(rm);
 647         }
 648
 649         if (rs) {
 650                 rds_wake_sk_sleep(rs);
 651                 sock_put(rds_rs_to_sk(rs));
 652         }
 653 }
 654
 655 /*
 656  * Transports call here when they've determined that the receiver queued
 657  * messages up to, and including, the given sequence number.  Messages are
 658  * moved to the retrans queue when rds_send_xmit picks them off the send
 659  * queue. This means that in the TCP case, the message may not have been
 660  * assigned the m_ack_seq yet - but that's fine as long as tcp_is_acked
 661  * checks the RDS_MSG_HAS_ACK_SEQ bit.
 662  *
 663  * XXX It's not clear to me how this is safely serialized with socket
 664  * destruction.  Maybe it should bail if it sees SOCK_DEAD.
 665  */
 666 void rds_send_drop_acked(struct rds_connection *conn, u64 ack,
 667                          is_acked_func is_acked)
 668 {
 669         struct rds_message *rm, *tmp;
 670         unsigned long flags;
 671         LIST_HEAD(list);
 672
 673         spin_lock_irqsave(&conn->c_lock, flags);
 674
 675         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
 676                 if (!rds_send_is_acked(rm, ack, is_acked))
 677                         break;
 678
 679                 list_move(&rm->m_conn_item, &list);
 680                 clear_bit(RDS_MSG_ON_CONN, &rm->m_flags);
 681         }
 682
 683         /* order flag updates with spin locks */
 684         if (!list_empty(&list))
 685                 smp_mb__after_clear_bit();
 686
 687         spin_unlock_irqrestore(&conn->c_lock, flags);
 688
 689         /* now remove the messages from the sock list as needed */
 690         rds_send_remove_from_sock(&list, RDS_RDMA_SUCCESS);
 691 }
 692 EXPORT_SYMBOL_GPL(rds_send_drop_acked);
 693
 694 void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest)
 695 {
 696         struct rds_message *rm, *tmp;
 697         struct rds_connection *conn;
 698         unsigned long flags;
 699         LIST_HEAD(list);
 700
 701         /* get all the messages we're dropping under the rs lock */
 702         spin_lock_irqsave(&rs->rs_lock, flags);
 703
 704         list_for_each_entry_safe(rm, tmp, &rs->rs_send_queue, m_sock_item) {
 705                 if (dest && (dest->sin_addr.s_addr != rm->m_daddr ||
 706                              dest->sin_port != rm->m_inc.i_hdr.h_dport))
 707                         continue;
 708
 709                 list_move(&rm->m_sock_item, &list);
 710                 rds_send_sndbuf_remove(rs, rm);
 711                 clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
 712         }
 713
 714         /* order flag updates with the rs lock */
 715         smp_mb__after_clear_bit();
 716
 717         spin_unlock_irqrestore(&rs->rs_lock, flags);
 718
 719         if (list_empty(&list))
 720                 return;
 721
 722         /* Remove the messages from the conn */
 723         list_for_each_entry(rm, &list, m_sock_item) {
 724
 725                 conn = rm->m_inc.i_conn;
 726
 727                 spin_lock_irqsave(&conn->c_lock, flags);
 728                 /*
 729                  * Maybe someone else beat us to removing rm from the conn.
 730                  * If we race with their flag update we'll get the lock and
 731                  * then really see that the flag has been cleared.
 732                  */
 733                 if (!test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) {
 734                         spin_unlock_irqrestore(&conn->c_lock, flags);
 735                         continue;
 736                 }
 737                 list_del_init(&rm->m_conn_item);
 738                 spin_unlock_irqrestore(&conn->c_lock, flags);
 739
 740                 /*
 741                  * Couldn't grab m_rs_lock in top loop (lock ordering),
 742                  * but we can now.
 743                  */
 744                 spin_lock_irqsave(&rm->m_rs_lock, flags);
 745
 746                 spin_lock(&rs->rs_lock);
 747                 __rds_send_complete(rs, rm, RDS_RDMA_CANCELED);
 748                 spin_unlock(&rs->rs_lock);
 749
 750                 rm->m_rs = NULL;
 751                 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 752
 753                 rds_message_put(rm);
 754         }
 755
 756         rds_wake_sk_sleep(rs);
 757
 758         while (!list_empty(&list)) {
 759                 rm = list_entry(list.next, struct rds_message, m_sock_item);
 760                 list_del_init(&rm->m_sock_item);
 761
 762                 rds_message_wait(rm);
 763                 rds_message_put(rm);
 764         }
 765 }
 766
 767 /*
 768  * we only want this to fire once so we use the callers 'queued'.  It's
 769  * possible that another thread can race with us and remove the
 770  * message from the flow with RDS_CANCEL_SENT_TO.
 771  */
 772 static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn,
 773                              struct rds_message *rm, __be16 sport,
 774                              __be16 dport, int *queued)
 775 {
 776         unsigned long flags;
 777         u32 len;
 778
 779         if (*queued)
 780                 goto out;
 781
 782         len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
 783
 784         /* this is the only place which holds both the socket's rs_lock
 785          * and the connection's c_lock */
 786         spin_lock_irqsave(&rs->rs_lock, flags);
 787
 788         /*
 789          * If there is a little space in sndbuf, we don't queue anything,
 790          * and userspace gets -EAGAIN. But poll() indicates there's send
 791          * room. This can lead to bad behavior (spinning) if snd_bytes isn't
 792          * freed up by incoming acks. So we check the *old* value of
 793          * rs_snd_bytes here to allow the last msg to exceed the buffer,
 794          * and poll() now knows no more data can be sent.
 795          */
 796         if (rs->rs_snd_bytes < rds_sk_sndbuf(rs)) {
 797                 rs->rs_snd_bytes += len;
 798
 799                 /* let recv side know we are close to send space exhaustion.
 800                  * This is probably not the optimal way to do it, as this
 801                  * means we set the flag on *all* messages as soon as our
 802                  * throughput hits a certain threshold.
 803                  */
 804                 if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2)
 805                         __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
 806
 807                 list_add_tail(&rm->m_sock_item, &rs->rs_send_queue);
 808                 set_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
 809                 rds_message_addref(rm);
 810                 rm->m_rs = rs;
 811
 812                 /* The code ordering is a little weird, but we're
 813                    trying to minimize the time we hold c_lock */
 814                 rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport, 0);
 815                 rm->m_inc.i_conn = conn;
 816                 rds_message_addref(rm);
 817
 818                 spin_lock(&conn->c_lock);
 819                 rm->m_inc.i_hdr.h_sequence = cpu_to_be64(conn->c_next_tx_seq++);
 820                 list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
 821                 set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
 822                 spin_unlock(&conn->c_lock);
 823
 824                 rdsdebug("queued msg %p len %d, rs %p bytes %d seq %llu\n",
 825                          rm, len, rs, rs->rs_snd_bytes,
 826                          (unsigned long long)be64_to_cpu(rm->m_inc.i_hdr.h_sequence));
 827
 828                 *queued = 1;
 829         }
 830
 831         spin_unlock_irqrestore(&rs->rs_lock, flags);
 832 out:
 833         return *queued;
 834 }
 835
 836 /*
 837  * rds_message is getting to be quite complicated, and we'd like to allocate
 838  * it all in one go. This figures out how big it needs to be up front.
 839  */
 840 static int rds_rm_size(struct msghdr *msg, int data_len)
 841 {
 842         struct cmsghdr *cmsg;
 843         int size = 0;
 844         int cmsg_groups = 0;
 845         int retval;
 846
 847         for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
 848                 if (!CMSG_OK(msg, cmsg))
 849                         return -EINVAL;
 850
 851                 if (cmsg->cmsg_level != SOL_RDS)
 852                         continue;
 853
 854                 switch (cmsg->cmsg_type) {
 855                 case RDS_CMSG_RDMA_ARGS:
 856                         cmsg_groups |= 1;
 857                         retval = rds_rdma_extra_size(CMSG_DATA(cmsg));
 858                         if (retval < 0)
 859                                 return retval;
 860                         size += retval;
 861
 862                         break;
 863
 864                 case RDS_CMSG_RDMA_DEST:
 865                 case RDS_CMSG_RDMA_MAP:
 866                         cmsg_groups |= 2;
 867                         /* these are valid but do no add any size */
 868                         break;
 869
 870                 case RDS_CMSG_ATOMIC_CSWP:
 871                 case RDS_CMSG_ATOMIC_FADD:
 872                         cmsg_groups |= 1;
 873                         size += sizeof(struct scatterlist);
 874                         break;
 875
 876                 default:
 877                         return -EINVAL;
 878                 }
 879
 880         }
 881
 882         size += ceil(data_len, PAGE_SIZE) * sizeof(struct scatterlist);
 883
 884         /* Ensure (DEST, MAP) are never used with (ARGS, ATOMIC) */
 885         if (cmsg_groups == 3)
 886                 return -EINVAL;
 887
 888         return size;
 889 }
 890
 891 static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
 892                          struct msghdr *msg, int *allocated_mr)
 893 {
 894         struct cmsghdr *cmsg;
 895         int ret = 0;
 896
 897         for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
 898                 if (!CMSG_OK(msg, cmsg))
 899                         return -EINVAL;
 900
 901                 if (cmsg->cmsg_level != SOL_RDS)
 902                         continue;
 903
 904                 /* As a side effect, RDMA_DEST and RDMA_MAP will set
 905                  * rm->rdma.m_rdma_cookie and rm->rdma.m_rdma_mr.
 906                  */
 907                 switch (cmsg->cmsg_type) {
 908                 case RDS_CMSG_RDMA_ARGS:
 909                         ret = rds_cmsg_rdma_args(rs, rm, cmsg);
 910                         break;
 911
 912                 case RDS_CMSG_RDMA_DEST:
 913                         ret = rds_cmsg_rdma_dest(rs, rm, cmsg);
 914                         break;
 915
 916                 case RDS_CMSG_RDMA_MAP:
 917                         ret = rds_cmsg_rdma_map(rs, rm, cmsg);
 918                         if (!ret)
 919                                 *allocated_mr = 1;
 920                         break;
 921                 case RDS_CMSG_ATOMIC_CSWP:
 922                 case RDS_CMSG_ATOMIC_FADD:
 923                         ret = rds_cmsg_atomic(rs, rm, cmsg);
 924                         break;
 925
 926                 default:
 927                         return -EINVAL;
 928                 }
 929
 930                 if (ret)
 931                         break;
 932         }
 933
 934         return ret;
 935 }
 936
 937 int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
 938                 size_t payload_len)
 939 {
 940         struct sock *sk = sock->sk;
 941         struct rds_sock *rs = rds_sk_to_rs(sk);
 942         struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name;
 943         __be32 daddr;
 944         __be16 dport;
 945         struct rds_message *rm = NULL;
 946         struct rds_connection *conn;
 947         int ret = 0;
 948         int queued = 0, allocated_mr = 0;
 949         int nonblock = msg->msg_flags & MSG_DONTWAIT;
 950         long timeo = sock_sndtimeo(sk, nonblock);
 951
 952         /* Mirror Linux UDP mirror of BSD error message compatibility */
 953         /* XXX: Perhaps MSG_MORE someday */
 954         if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) {
 955                 printk(KERN_INFO "msg_flags 0x%08X\n", msg->msg_flags);
 956                 ret = -EOPNOTSUPP;
 957                 goto out;
 958         }
 959
 960         if (msg->msg_namelen) {
 961                 /* XXX fail non-unicast destination IPs? */
 962                 if (msg->msg_namelen < sizeof(*usin) || usin->sin_family != AF_INET) {
 963                         ret = -EINVAL;
 964                         goto out;
 965                 }
 966                 daddr = usin->sin_addr.s_addr;
 967                 dport = usin->sin_port;
 968         } else {
 969                 /* We only care about consistency with ->connect() */
 970                 lock_sock(sk);
 971                 daddr = rs->rs_conn_addr;
 972                 dport = rs->rs_conn_port;
 973                 release_sock(sk);
 974         }
 975
 976         /* racing with another thread binding seems ok here */
 977         if (daddr == 0 || rs->rs_bound_addr == 0) {
 978                 ret = -ENOTCONN; /* XXX not a great errno */
 979                 goto out;
 980         }
 981
 982         /* size of rm including all sgs */
 983         ret = rds_rm_size(msg, payload_len);
 984         if (ret < 0)
 985                 goto out;
 986
 987         rm = rds_message_alloc(ret, GFP_KERNEL);
 988         if (!rm) {
 989                 ret = -ENOMEM;
 990                 goto out;
 991         }
 992
 993         /* Attach data to the rm */
 994         if (payload_len) {
 995                 rm->data.op_sg = rds_message_alloc_sgs(rm, ceil(payload_len, PAGE_SIZE));
 996                 ret = rds_message_copy_from_user(rm, msg->msg_iov, payload_len);
 997                 if (ret)
 998                         goto out;
 999         }
1000         rm->data.op_active = 1;
1001
1002         rm->m_daddr = daddr;
1003
1004         /* rds_conn_create has a spinlock that runs with IRQ off.
1005          * Caching the conn in the socket helps a lot. */
1006         if (rs->rs_conn && rs->rs_conn->c_faddr == daddr)
1007                 conn = rs->rs_conn;
1008         else {
1009                 conn = rds_conn_create_outgoing(rs->rs_bound_addr, daddr,
1010                                         rs->rs_transport,
1011                                         sock->sk->sk_allocation);
1012                 if (IS_ERR(conn)) {
1013                         ret = PTR_ERR(conn);
1014                         goto out;
1015                 }
1016                 rs->rs_conn = conn;
1017         }
1018
1019         /* Parse any control messages the user may have included. */
1020         ret = rds_cmsg_send(rs, rm, msg, &allocated_mr);
1021         if (ret)
1022                 goto out;
1023
1024         if (rm->rdma.op_active && !conn->c_trans->xmit_rdma) {
1025                 if (printk_ratelimit())
1026                         printk(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",
1027                                &rm->rdma, conn->c_trans->xmit_rdma);
1028                 ret = -EOPNOTSUPP;
1029                 goto out;
1030         }
1031
1032         if (rm->atomic.op_active && !conn->c_trans->xmit_atomic) {
1033                 if (printk_ratelimit())
1034                         printk(KERN_NOTICE "atomic_op %p conn xmit_atomic %p\n",
1035                                &rm->atomic, conn->c_trans->xmit_atomic);
1036                 ret = -EOPNOTSUPP;
1037                 goto out;
1038         }
1039
1040         /* If the connection is down, trigger a connect. We may
1041          * have scheduled a delayed reconnect however - in this case
1042          * we should not interfere.
1043          */
1044         if (rds_conn_state(conn) == RDS_CONN_DOWN &&
1045             !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
1046                 queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
1047
1048         ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);
1049         if (ret) {
1050                 rs->rs_seen_congestion = 1;
1051                 goto out;
1052         }
1053
1054         while (!rds_send_queue_rm(rs, conn, rm, rs->rs_bound_port,
1055                                   dport, &queued)) {
1056                 rds_stats_inc(s_send_queue_full);
1057                 /* XXX make sure this is reasonable */
1058                 if (payload_len > rds_sk_sndbuf(rs)) {
1059                         ret = -EMSGSIZE;
1060                         goto out;
1061                 }
1062                 if (nonblock) {
1063                         ret = -EAGAIN;
1064                         goto out;
1065                 }
1066
1067                 timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
1068                                         rds_send_queue_rm(rs, conn, rm,
1069                                                           rs->rs_bound_port,
1070                                                           dport,
1071                                                           &queued),
1072                                         timeo);
1073                 rdsdebug("sendmsg woke queued %d timeo %ld\n", queued, timeo);
1074                 if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
1075                         continue;
1076
1077                 ret = timeo;
1078                 if (ret == 0)
1079                         ret = -ETIMEDOUT;
1080                 goto out;
1081         }
1082
1083         /*
1084          * By now we've committed to the send.  We reuse rds_send_worker()
1085          * to retry sends in the rds thread if the transport asks us to.
1086          */
1087         rds_stats_inc(s_send_queued);
1088
1089         if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
1090                 rds_send_xmit(conn);
1091
1092         rds_message_put(rm);
1093         return payload_len;
1094
1095 out:
1096         /* If the user included a RDMA_MAP cmsg, we allocated a MR on the fly.
1097          * If the sendmsg goes through, we keep the MR. If it fails with EAGAIN
1098          * or in any other way, we need to destroy the MR again */
1099         if (allocated_mr)
1100                 rds_rdma_unuse(rs, rds_rdma_cookie_key(rm->m_rdma_cookie), 1);
1101
1102         if (rm)
1103                 rds_message_put(rm);
1104         return ret;
1105 }
1106
1107 /*
1108  * Reply to a ping packet.
1109  */
1110 int
1111 rds_send_pong(struct rds_connection *conn, __be16 dport)
1112 {
1113         struct rds_message *rm;
1114         unsigned long flags;
1115         int ret = 0;
1116
1117         rm = rds_message_alloc(0, GFP_ATOMIC);
1118         if (!rm) {
1119                 ret = -ENOMEM;
1120                 goto out;
1121         }
1122
1123         rm->m_daddr = conn->c_faddr;
1124         rm->data.op_active = 1;
1125
1126         /* If the connection is down, trigger a connect. We may
1127          * have scheduled a delayed reconnect however - in this case
1128          * we should not interfere.
1129          */
1130         if (rds_conn_state(conn) == RDS_CONN_DOWN &&
1131             !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
1132                 queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
1133
1134         ret = rds_cong_wait(conn->c_fcong, dport, 1, NULL);
1135         if (ret)
1136                 goto out;
1137
1138         spin_lock_irqsave(&conn->c_lock, flags);
1139         list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
1140         set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
1141         rds_message_addref(rm);
1142         rm->m_inc.i_conn = conn;
1143
1144         rds_message_populate_header(&rm->m_inc.i_hdr, 0, dport,
1145                                     conn->c_next_tx_seq);
1146         conn->c_next_tx_seq++;
1147         spin_unlock_irqrestore(&conn->c_lock, flags);
1148
1149         rds_stats_inc(s_send_queued);
1150         rds_stats_inc(s_send_pong);
1151
1152         if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
1153                 rds_send_xmit(conn);
1154
1155         rds_message_put(rm);
1156         return 0;
1157
1158 out:
1159         if (rm)
1160                 rds_message_put(rm);
1161         return ret;
1162 }