linux/net/rds/send.c
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   1/*
   2 * Copyright (c) 2006 Oracle.  All rights reserved.
   3 *
   4 * This software is available to you under a choice of one of two
   5 * licenses.  You may choose to be licensed under the terms of the GNU
   6 * General Public License (GPL) Version 2, available from the file
   7 * COPYING in the main directory of this source tree, or the
   8 * OpenIB.org BSD license below:
   9 *
  10 *     Redistribution and use in source and binary forms, with or
  11 *     without modification, are permitted provided that the following
  12 *     conditions are met:
  13 *
  14 *      - Redistributions of source code must retain the above
  15 *        copyright notice, this list of conditions and the following
  16 *        disclaimer.
  17 *
  18 *      - Redistributions in binary form must reproduce the above
  19 *        copyright notice, this list of conditions and the following
  20 *        disclaimer in the documentation and/or other materials
  21 *        provided with the distribution.
  22 *
  23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  30 * SOFTWARE.
  31 *
  32 */
  33#include <linux/kernel.h>
  34#include <linux/moduleparam.h>
  35#include <linux/gfp.h>
  36#include <net/sock.h>
  37#include <linux/in.h>
  38#include <linux/list.h>
  39#include <linux/ratelimit.h>
  40#include <linux/export.h>
  41
  42#include "rds.h"
  43
  44/* When transmitting messages in rds_send_xmit, we need to emerge from
  45 * time to time and briefly release the CPU. Otherwise the softlock watchdog
  46 * will kick our shin.
  47 * Also, it seems fairer to not let one busy connection stall all the
  48 * others.
  49 *
  50 * send_batch_count is the number of times we'll loop in send_xmit. Setting
  51 * it to 0 will restore the old behavior (where we looped until we had
  52 * drained the queue).
  53 */
  54static int send_batch_count = 64;
  55module_param(send_batch_count, int, 0444);
  56MODULE_PARM_DESC(send_batch_count, " batch factor when working the send queue");
  57
  58static void rds_send_remove_from_sock(struct list_head *messages, int status);
  59
  60/*
  61 * Reset the send state.  Callers must ensure that this doesn't race with
  62 * rds_send_xmit().
  63 */
  64void rds_send_reset(struct rds_connection *conn)
  65{
  66        struct rds_message *rm, *tmp;
  67        unsigned long flags;
  68
  69        if (conn->c_xmit_rm) {
  70                rm = conn->c_xmit_rm;
  71                conn->c_xmit_rm = NULL;
  72                /* Tell the user the RDMA op is no longer mapped by the
  73                 * transport. This isn't entirely true (it's flushed out
  74                 * independently) but as the connection is down, there's
  75                 * no ongoing RDMA to/from that memory */
  76                rds_message_unmapped(rm);
  77                rds_message_put(rm);
  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
 102static int acquire_in_xmit(struct rds_connection *conn)
 103{
 104        return test_and_set_bit(RDS_IN_XMIT, &conn->c_flags) == 0;
 105}
 106
 107static void release_in_xmit(struct rds_connection *conn)
 108{
 109        clear_bit(RDS_IN_XMIT, &conn->c_flags);
 110        smp_mb__after_clear_bit();
 111        /*
 112         * We don't use wait_on_bit()/wake_up_bit() because our waking is in a
 113         * hot path and finding waiters is very rare.  We don't want to walk
 114         * the system-wide hashed waitqueue buckets in the fast path only to
 115         * almost never find waiters.
 116         */
 117        if (waitqueue_active(&conn->c_waitq))
 118                wake_up_all(&conn->c_waitq);
 119}
 120
 121/*
 122 * We're making the conscious trade-off here to only send one message
 123 * down the connection at a time.
 124 *   Pro:
 125 *      - tx queueing is a simple fifo list
 126 *      - reassembly is optional and easily done by transports per conn
 127 *      - no per flow rx lookup at all, straight to the socket
 128 *      - less per-frag memory and wire overhead
 129 *   Con:
 130 *      - queued acks can be delayed behind large messages
 131 *   Depends:
 132 *      - small message latency is higher behind queued large messages
 133 *      - large message latency isn't starved by intervening small sends
 134 */
 135int rds_send_xmit(struct rds_connection *conn)
 136{
 137        struct rds_message *rm;
 138        unsigned long flags;
 139        unsigned int tmp;
 140        struct scatterlist *sg;
 141        int ret = 0;
 142        LIST_HEAD(to_be_dropped);
 143
 144restart:
 145
 146        /*
 147         * sendmsg calls here after having queued its message on the send
 148         * queue.  We only have one task feeding the connection at a time.  If
 149         * another thread is already feeding the queue then we back off.  This
 150         * avoids blocking the caller and trading per-connection data between
 151         * caches per message.
 152         */
 153        if (!acquire_in_xmit(conn)) {
 154                rds_stats_inc(s_send_lock_contention);
 155                ret = -ENOMEM;
 156                goto out;
 157        }
 158
 159        /*
 160         * rds_conn_shutdown() sets the conn state and then tests RDS_IN_XMIT,
 161         * we do the opposite to avoid races.
 162         */
 163        if (!rds_conn_up(conn)) {
 164                release_in_xmit(conn);
 165                ret = 0;
 166                goto out;
 167        }
 168
 169        if (conn->c_trans->xmit_prepare)
 170                conn->c_trans->xmit_prepare(conn);
 171
 172        /*
 173         * spin trying to push headers and data down the connection until
 174         * the connection doesn't make forward progress.
 175         */
 176        while (1) {
 177
 178                rm = conn->c_xmit_rm;
 179
 180                /*
 181                 * If between sending messages, we can send a pending congestion
 182                 * map update.
 183                 */
 184                if (!rm && test_and_clear_bit(0, &conn->c_map_queued)) {
 185                        rm = rds_cong_update_alloc(conn);
 186                        if (IS_ERR(rm)) {
 187                                ret = PTR_ERR(rm);
 188                                break;
 189                        }
 190                        rm->data.op_active = 1;
 191
 192                        conn->c_xmit_rm = rm;
 193                }
 194
 195                /*
 196                 * If not already working on one, grab the next message.
 197                 *
 198                 * c_xmit_rm holds a ref while we're sending this message down
 199                 * the connction.  We can use this ref while holding the
 200                 * send_sem.. rds_send_reset() is serialized with it.
 201                 */
 202                if (!rm) {
 203                        unsigned int len;
 204
 205                        spin_lock_irqsave(&conn->c_lock, flags);
 206
 207                        if (!list_empty(&conn->c_send_queue)) {
 208                                rm = list_entry(conn->c_send_queue.next,
 209                                                struct rds_message,
 210                                                m_conn_item);
 211                                rds_message_addref(rm);
 212
 213                                /*
 214                                 * Move the message from the send queue to the retransmit
 215                                 * list right away.
 216                                 */
 217                                list_move_tail(&rm->m_conn_item, &conn->c_retrans);
 218                        }
 219
 220                        spin_unlock_irqrestore(&conn->c_lock, flags);
 221
 222                        if (!rm)
 223                                break;
 224
 225                        /* Unfortunately, the way Infiniband deals with
 226                         * RDMA to a bad MR key is by moving the entire
 227                         * queue pair to error state. We cold possibly
 228                         * recover from that, but right now we drop the
 229                         * connection.
 230                         * Therefore, we never retransmit messages with RDMA ops.
 231                         */
 232                        if (rm->rdma.op_active &&
 233                            test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) {
 234                                spin_lock_irqsave(&conn->c_lock, flags);
 235                                if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags))
 236                                        list_move(&rm->m_conn_item, &to_be_dropped);
 237                                spin_unlock_irqrestore(&conn->c_lock, flags);
 238                                continue;
 239                        }
 240
 241                        /* Require an ACK every once in a while */
 242                        len = ntohl(rm->m_inc.i_hdr.h_len);
 243                        if (conn->c_unacked_packets == 0 ||
 244                            conn->c_unacked_bytes < len) {
 245                                __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
 246
 247                                conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
 248                                conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
 249                                rds_stats_inc(s_send_ack_required);
 250                        } else {
 251                                conn->c_unacked_bytes -= len;
 252                                conn->c_unacked_packets--;
 253                        }
 254
 255                        conn->c_xmit_rm = rm;
 256                }
 257
 258                /* The transport either sends the whole rdma or none of it */
 259                if (rm->rdma.op_active && !conn->c_xmit_rdma_sent) {
 260                        rm->m_final_op = &rm->rdma;
 261                        ret = conn->c_trans->xmit_rdma(conn, &rm->rdma);
 262                        if (ret)
 263                                break;
 264                        conn->c_xmit_rdma_sent = 1;
 265
 266                        /* The transport owns the mapped memory for now.
 267                         * You can't unmap it while it's on the send queue */
 268                        set_bit(RDS_MSG_MAPPED, &rm->m_flags);
 269                }
 270
 271                if (rm->atomic.op_active && !conn->c_xmit_atomic_sent) {
 272                        rm->m_final_op = &rm->atomic;
 273                        ret = conn->c_trans->xmit_atomic(conn, &rm->atomic);
 274                        if (ret)
 275                                break;
 276                        conn->c_xmit_atomic_sent = 1;
 277
 278                        /* The transport owns the mapped memory for now.
 279                         * You can't unmap it while it's on the send queue */
 280                        set_bit(RDS_MSG_MAPPED, &rm->m_flags);
 281                }
 282
 283                /*
 284                 * A number of cases require an RDS header to be sent
 285                 * even if there is no data.
 286                 * We permit 0-byte sends; rds-ping depends on this.
 287                 * However, if there are exclusively attached silent ops,
 288                 * we skip the hdr/data send, to enable silent operation.
 289                 */
 290                if (rm->data.op_nents == 0) {
 291                        int ops_present;
 292                        int all_ops_are_silent = 1;
 293
 294                        ops_present = (rm->atomic.op_active || rm->rdma.op_active);
 295                        if (rm->atomic.op_active && !rm->atomic.op_silent)
 296                                all_ops_are_silent = 0;
 297                        if (rm->rdma.op_active && !rm->rdma.op_silent)
 298                                all_ops_are_silent = 0;
 299
 300                        if (ops_present && all_ops_are_silent
 301                            && !rm->m_rdma_cookie)
 302                                rm->data.op_active = 0;
 303                }
 304
 305                if (rm->data.op_active && !conn->c_xmit_data_sent) {
 306                        rm->m_final_op = &rm->data;
 307                        ret = conn->c_trans->xmit(conn, rm,
 308                                                  conn->c_xmit_hdr_off,
 309                                                  conn->c_xmit_sg,
 310                                                  conn->c_xmit_data_off);
 311                        if (ret <= 0)
 312                                break;
 313
 314                        if (conn->c_xmit_hdr_off < sizeof(struct rds_header)) {
 315                                tmp = min_t(int, ret,
 316                                            sizeof(struct rds_header) -
 317                                            conn->c_xmit_hdr_off);
 318                                conn->c_xmit_hdr_off += tmp;
 319                                ret -= tmp;
 320                        }
 321
 322                        sg = &rm->data.op_sg[conn->c_xmit_sg];
 323                        while (ret) {
 324                                tmp = min_t(int, ret, sg->length -
 325                                                      conn->c_xmit_data_off);
 326                                conn->c_xmit_data_off += tmp;
 327                                ret -= tmp;
 328                                if (conn->c_xmit_data_off == sg->length) {
 329                                        conn->c_xmit_data_off = 0;
 330                                        sg++;
 331                                        conn->c_xmit_sg++;
 332                                        BUG_ON(ret != 0 &&
 333                                               conn->c_xmit_sg == rm->data.op_nents);
 334                                }
 335                        }
 336
 337                        if (conn->c_xmit_hdr_off == sizeof(struct rds_header) &&
 338                            (conn->c_xmit_sg == rm->data.op_nents))
 339                                conn->c_xmit_data_sent = 1;
 340                }
 341
 342                /*
 343                 * A rm will only take multiple times through this loop
 344                 * if there is a data op. Thus, if the data is sent (or there was
 345                 * none), then we're done with the rm.
 346                 */
 347                if (!rm->data.op_active || conn->c_xmit_data_sent) {
 348                        conn->c_xmit_rm = NULL;
 349                        conn->c_xmit_sg = 0;
 350                        conn->c_xmit_hdr_off = 0;
 351                        conn->c_xmit_data_off = 0;
 352                        conn->c_xmit_rdma_sent = 0;
 353                        conn->c_xmit_atomic_sent = 0;
 354                        conn->c_xmit_data_sent = 0;
 355
 356                        rds_message_put(rm);
 357                }
 358        }
 359
 360        if (conn->c_trans->xmit_complete)
 361                conn->c_trans->xmit_complete(conn);
 362
 363        release_in_xmit(conn);
 364
 365        /* Nuke any messages we decided not to retransmit. */
 366        if (!list_empty(&to_be_dropped)) {
 367                /* irqs on here, so we can put(), unlike above */
 368                list_for_each_entry(rm, &to_be_dropped, m_conn_item)
 369                        rds_message_put(rm);
 370                rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED);
 371        }
 372
 373        /*
 374         * Other senders can queue a message after we last test the send queue
 375         * but before we clear RDS_IN_XMIT.  In that case they'd back off and
 376         * not try and send their newly queued message.  We need to check the
 377         * send queue after having cleared RDS_IN_XMIT so that their message
 378         * doesn't get stuck on the send queue.
 379         *
 380         * If the transport cannot continue (i.e ret != 0), then it must
 381         * call us when more room is available, such as from the tx
 382         * completion handler.
 383         */
 384        if (ret == 0) {
 385                smp_mb();
 386                if (!list_empty(&conn->c_send_queue)) {
 387                        rds_stats_inc(s_send_lock_queue_raced);
 388                        goto restart;
 389                }
 390        }
 391out:
 392        return ret;
 393}
 394
 395static void rds_send_sndbuf_remove(struct rds_sock *rs, struct rds_message *rm)
 396{
 397        u32 len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
 398
 399        assert_spin_locked(&rs->rs_lock);
 400
 401        BUG_ON(rs->rs_snd_bytes < len);
 402        rs->rs_snd_bytes -= len;
 403
 404        if (rs->rs_snd_bytes == 0)
 405                rds_stats_inc(s_send_queue_empty);
 406}
 407
 408static inline int rds_send_is_acked(struct rds_message *rm, u64 ack,
 409                                    is_acked_func is_acked)
 410{
 411        if (is_acked)
 412                return is_acked(rm, ack);
 413        return be64_to_cpu(rm->m_inc.i_hdr.h_sequence) <= ack;
 414}
 415
 416/*
 417 * This is pretty similar to what happens below in the ACK
 418 * handling code - except that we call here as soon as we get
 419 * the IB send completion on the RDMA op and the accompanying
 420 * message.
 421 */
 422void rds_rdma_send_complete(struct rds_message *rm, int status)
 423{
 424        struct rds_sock *rs = NULL;
 425        struct rm_rdma_op *ro;
 426        struct rds_notifier *notifier;
 427        unsigned long flags;
 428
 429        spin_lock_irqsave(&rm->m_rs_lock, flags);
 430
 431        ro = &rm->rdma;
 432        if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) &&
 433            ro->op_active && ro->op_notify && ro->op_notifier) {
 434                notifier = ro->op_notifier;
 435                rs = rm->m_rs;
 436                sock_hold(rds_rs_to_sk(rs));
 437
 438                notifier->n_status = status;
 439                spin_lock(&rs->rs_lock);
 440                list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
 441                spin_unlock(&rs->rs_lock);
 442
 443                ro->op_notifier = NULL;
 444        }
 445
 446        spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 447
 448        if (rs) {
 449                rds_wake_sk_sleep(rs);
 450                sock_put(rds_rs_to_sk(rs));
 451        }
 452}
 453EXPORT_SYMBOL_GPL(rds_rdma_send_complete);
 454
 455/*
 456 * Just like above, except looks at atomic op
 457 */
 458void rds_atomic_send_complete(struct rds_message *rm, int status)
 459{
 460        struct rds_sock *rs = NULL;
 461        struct rm_atomic_op *ao;
 462        struct rds_notifier *notifier;
 463        unsigned long flags;
 464
 465        spin_lock_irqsave(&rm->m_rs_lock, flags);
 466
 467        ao = &rm->atomic;
 468        if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags)
 469            && ao->op_active && ao->op_notify && ao->op_notifier) {
 470                notifier = ao->op_notifier;
 471                rs = rm->m_rs;
 472                sock_hold(rds_rs_to_sk(rs));
 473
 474                notifier->n_status = status;
 475                spin_lock(&rs->rs_lock);
 476                list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
 477                spin_unlock(&rs->rs_lock);
 478
 479                ao->op_notifier = NULL;
 480        }
 481
 482        spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 483
 484        if (rs) {
 485                rds_wake_sk_sleep(rs);
 486                sock_put(rds_rs_to_sk(rs));
 487        }
 488}
 489EXPORT_SYMBOL_GPL(rds_atomic_send_complete);
 490
 491/*
 492 * This is the same as rds_rdma_send_complete except we
 493 * don't do any locking - we have all the ingredients (message,
 494 * socket, socket lock) and can just move the notifier.
 495 */
 496static inline void
 497__rds_send_complete(struct rds_sock *rs, struct rds_message *rm, int status)
 498{
 499        struct rm_rdma_op *ro;
 500        struct rm_atomic_op *ao;
 501
 502        ro = &rm->rdma;
 503        if (ro->op_active && ro->op_notify && ro->op_notifier) {
 504                ro->op_notifier->n_status = status;
 505                list_add_tail(&ro->op_notifier->n_list, &rs->rs_notify_queue);
 506                ro->op_notifier = NULL;
 507        }
 508
 509        ao = &rm->atomic;
 510        if (ao->op_active && ao->op_notify && ao->op_notifier) {
 511                ao->op_notifier->n_status = status;
 512                list_add_tail(&ao->op_notifier->n_list, &rs->rs_notify_queue);
 513                ao->op_notifier = NULL;
 514        }
 515
 516        /* No need to wake the app - caller does this */
 517}
 518
 519/*
 520 * This is called from the IB send completion when we detect
 521 * a RDMA operation that failed with remote access error.
 522 * So speed is not an issue here.
 523 */
 524struct rds_message *rds_send_get_message(struct rds_connection *conn,
 525                                         struct rm_rdma_op *op)
 526{
 527        struct rds_message *rm, *tmp, *found = NULL;
 528        unsigned long flags;
 529
 530        spin_lock_irqsave(&conn->c_lock, flags);
 531
 532        list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
 533                if (&rm->rdma == op) {
 534                        atomic_inc(&rm->m_refcount);
 535                        found = rm;
 536                        goto out;
 537                }
 538        }
 539
 540        list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
 541                if (&rm->rdma == op) {
 542                        atomic_inc(&rm->m_refcount);
 543                        found = rm;
 544                        break;
 545                }
 546        }
 547
 548out:
 549        spin_unlock_irqrestore(&conn->c_lock, flags);
 550
 551        return found;
 552}
 553EXPORT_SYMBOL_GPL(rds_send_get_message);
 554
 555/*
 556 * This removes messages from the socket's list if they're on it.  The list
 557 * argument must be private to the caller, we must be able to modify it
 558 * without locks.  The messages must have a reference held for their
 559 * position on the list.  This function will drop that reference after
 560 * removing the messages from the 'messages' list regardless of if it found
 561 * the messages on the socket list or not.
 562 */
 563static void rds_send_remove_from_sock(struct list_head *messages, int status)
 564{
 565        unsigned long flags;
 566        struct rds_sock *rs = NULL;
 567        struct rds_message *rm;
 568
 569        while (!list_empty(messages)) {
 570                int was_on_sock = 0;
 571
 572                rm = list_entry(messages->next, struct rds_message,
 573                                m_conn_item);
 574                list_del_init(&rm->m_conn_item);
 575
 576                /*
 577                 * If we see this flag cleared then we're *sure* that someone
 578                 * else beat us to removing it from the sock.  If we race
 579                 * with their flag update we'll get the lock and then really
 580                 * see that the flag has been cleared.
 581                 *
 582                 * The message spinlock makes sure nobody clears rm->m_rs
 583                 * while we're messing with it. It does not prevent the
 584                 * message from being removed from the socket, though.
 585                 */
 586                spin_lock_irqsave(&rm->m_rs_lock, flags);
 587                if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags))
 588                        goto unlock_and_drop;
 589
 590                if (rs != rm->m_rs) {
 591                        if (rs) {
 592                                rds_wake_sk_sleep(rs);
 593                                sock_put(rds_rs_to_sk(rs));
 594                        }
 595                        rs = rm->m_rs;
 596                        sock_hold(rds_rs_to_sk(rs));
 597                }
 598                spin_lock(&rs->rs_lock);
 599
 600                if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) {
 601                        struct rm_rdma_op *ro = &rm->rdma;
 602                        struct rds_notifier *notifier;
 603
 604                        list_del_init(&rm->m_sock_item);
 605                        rds_send_sndbuf_remove(rs, rm);
 606
 607                        if (ro->op_active && ro->op_notifier &&
 608                               (ro->op_notify || (ro->op_recverr && status))) {
 609                                notifier = ro->op_notifier;
 610                                list_add_tail(&notifier->n_list,
 611                                                &rs->rs_notify_queue);
 612                                if (!notifier->n_status)
 613                                        notifier->n_status = status;
 614                                rm->rdma.op_notifier = NULL;
 615                        }
 616                        was_on_sock = 1;
 617                        rm->m_rs = NULL;
 618                }
 619                spin_unlock(&rs->rs_lock);
 620
 621unlock_and_drop:
 622                spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 623                rds_message_put(rm);
 624                if (was_on_sock)
 625                        rds_message_put(rm);
 626        }
 627
 628        if (rs) {
 629                rds_wake_sk_sleep(rs);
 630                sock_put(rds_rs_to_sk(rs));
 631        }
 632}
 633
 634/*
 635 * Transports call here when they've determined that the receiver queued
 636 * messages up to, and including, the given sequence number.  Messages are
 637 * moved to the retrans queue when rds_send_xmit picks them off the send
 638 * queue. This means that in the TCP case, the message may not have been
 639 * assigned the m_ack_seq yet - but that's fine as long as tcp_is_acked
 640 * checks the RDS_MSG_HAS_ACK_SEQ bit.
 641 *
 642 * XXX It's not clear to me how this is safely serialized with socket
 643 * destruction.  Maybe it should bail if it sees SOCK_DEAD.
 644 */
 645void rds_send_drop_acked(struct rds_connection *conn, u64 ack,
 646                         is_acked_func is_acked)
 647{
 648        struct rds_message *rm, *tmp;
 649        unsigned long flags;
 650        LIST_HEAD(list);
 651
 652        spin_lock_irqsave(&conn->c_lock, flags);
 653
 654        list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
 655                if (!rds_send_is_acked(rm, ack, is_acked))
 656                        break;
 657
 658                list_move(&rm->m_conn_item, &list);
 659                clear_bit(RDS_MSG_ON_CONN, &rm->m_flags);
 660        }
 661
 662        /* order flag updates with spin locks */
 663        if (!list_empty(&list))
 664                smp_mb__after_clear_bit();
 665
 666        spin_unlock_irqrestore(&conn->c_lock, flags);
 667
 668        /* now remove the messages from the sock list as needed */
 669        rds_send_remove_from_sock(&list, RDS_RDMA_SUCCESS);
 670}
 671EXPORT_SYMBOL_GPL(rds_send_drop_acked);
 672
 673void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest)
 674{
 675        struct rds_message *rm, *tmp;
 676        struct rds_connection *conn;
 677        unsigned long flags;
 678        LIST_HEAD(list);
 679
 680        /* get all the messages we're dropping under the rs lock */
 681        spin_lock_irqsave(&rs->rs_lock, flags);
 682
 683        list_for_each_entry_safe(rm, tmp, &rs->rs_send_queue, m_sock_item) {
 684                if (dest && (dest->sin_addr.s_addr != rm->m_daddr ||
 685                             dest->sin_port != rm->m_inc.i_hdr.h_dport))
 686                        continue;
 687
 688                list_move(&rm->m_sock_item, &list);
 689                rds_send_sndbuf_remove(rs, rm);
 690                clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
 691        }
 692
 693        /* order flag updates with the rs lock */
 694        smp_mb__after_clear_bit();
 695
 696        spin_unlock_irqrestore(&rs->rs_lock, flags);
 697
 698        if (list_empty(&list))
 699                return;
 700
 701        /* Remove the messages from the conn */
 702        list_for_each_entry(rm, &list, m_sock_item) {
 703
 704                conn = rm->m_inc.i_conn;
 705
 706                spin_lock_irqsave(&conn->c_lock, flags);
 707                /*
 708                 * Maybe someone else beat us to removing rm from the conn.
 709                 * If we race with their flag update we'll get the lock and
 710                 * then really see that the flag has been cleared.
 711                 */
 712                if (!test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) {
 713                        spin_unlock_irqrestore(&conn->c_lock, flags);
 714                        continue;
 715                }
 716                list_del_init(&rm->m_conn_item);
 717                spin_unlock_irqrestore(&conn->c_lock, flags);
 718
 719                /*
 720                 * Couldn't grab m_rs_lock in top loop (lock ordering),
 721                 * but we can now.
 722                 */
 723                spin_lock_irqsave(&rm->m_rs_lock, flags);
 724
 725                spin_lock(&rs->rs_lock);
 726                __rds_send_complete(rs, rm, RDS_RDMA_CANCELED);
 727                spin_unlock(&rs->rs_lock);
 728
 729                rm->m_rs = NULL;
 730                spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 731
 732                rds_message_put(rm);
 733        }
 734
 735        rds_wake_sk_sleep(rs);
 736
 737        while (!list_empty(&list)) {
 738                rm = list_entry(list.next, struct rds_message, m_sock_item);
 739                list_del_init(&rm->m_sock_item);
 740
 741                rds_message_wait(rm);
 742                rds_message_put(rm);
 743        }
 744}
 745
 746/*
 747 * we only want this to fire once so we use the callers 'queued'.  It's
 748 * possible that another thread can race with us and remove the
 749 * message from the flow with RDS_CANCEL_SENT_TO.
 750 */
 751static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn,
 752                             struct rds_message *rm, __be16 sport,
 753                             __be16 dport, int *queued)
 754{
 755        unsigned long flags;
 756        u32 len;
 757
 758        if (*queued)
 759                goto out;
 760
 761        len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
 762
 763        /* this is the only place which holds both the socket's rs_lock
 764         * and the connection's c_lock */
 765        spin_lock_irqsave(&rs->rs_lock, flags);
 766
 767        /*
 768         * If there is a little space in sndbuf, we don't queue anything,
 769         * and userspace gets -EAGAIN. But poll() indicates there's send
 770         * room. This can lead to bad behavior (spinning) if snd_bytes isn't
 771         * freed up by incoming acks. So we check the *old* value of
 772         * rs_snd_bytes here to allow the last msg to exceed the buffer,
 773         * and poll() now knows no more data can be sent.
 774         */
 775        if (rs->rs_snd_bytes < rds_sk_sndbuf(rs)) {
 776                rs->rs_snd_bytes += len;
 777
 778                /* let recv side know we are close to send space exhaustion.
 779                 * This is probably not the optimal way to do it, as this
 780                 * means we set the flag on *all* messages as soon as our
 781                 * throughput hits a certain threshold.
 782                 */
 783                if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2)
 784                        __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
 785
 786                list_add_tail(&rm->m_sock_item, &rs->rs_send_queue);
 787                set_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
 788                rds_message_addref(rm);
 789                rm->m_rs = rs;
 790
 791                /* The code ordering is a little weird, but we're
 792                   trying to minimize the time we hold c_lock */
 793                rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport, 0);
 794                rm->m_inc.i_conn = conn;
 795                rds_message_addref(rm);
 796
 797                spin_lock(&conn->c_lock);
 798                rm->m_inc.i_hdr.h_sequence = cpu_to_be64(conn->c_next_tx_seq++);
 799                list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
 800                set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
 801                spin_unlock(&conn->c_lock);
 802
 803                rdsdebug("queued msg %p len %d, rs %p bytes %d seq %llu\n",
 804                         rm, len, rs, rs->rs_snd_bytes,
 805                         (unsigned long long)be64_to_cpu(rm->m_inc.i_hdr.h_sequence));
 806
 807                *queued = 1;
 808        }
 809
 810        spin_unlock_irqrestore(&rs->rs_lock, flags);
 811out:
 812        return *queued;
 813}
 814
 815/*
 816 * rds_message is getting to be quite complicated, and we'd like to allocate
 817 * it all in one go. This figures out how big it needs to be up front.
 818 */
 819static int rds_rm_size(struct msghdr *msg, int data_len)
 820{
 821        struct cmsghdr *cmsg;
 822        int size = 0;
 823        int cmsg_groups = 0;
 824        int retval;
 825
 826        for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
 827                if (!CMSG_OK(msg, cmsg))
 828                        return -EINVAL;
 829
 830                if (cmsg->cmsg_level != SOL_RDS)
 831                        continue;
 832
 833                switch (cmsg->cmsg_type) {
 834                case RDS_CMSG_RDMA_ARGS:
 835                        cmsg_groups |= 1;
 836                        retval = rds_rdma_extra_size(CMSG_DATA(cmsg));
 837                        if (retval < 0)
 838                                return retval;
 839                        size += retval;
 840
 841                        break;
 842
 843                case RDS_CMSG_RDMA_DEST:
 844                case RDS_CMSG_RDMA_MAP:
 845                        cmsg_groups |= 2;
 846                        /* these are valid but do no add any size */
 847                        break;
 848
 849                case RDS_CMSG_ATOMIC_CSWP:
 850                case RDS_CMSG_ATOMIC_FADD:
 851                case RDS_CMSG_MASKED_ATOMIC_CSWP:
 852                case RDS_CMSG_MASKED_ATOMIC_FADD:
 853                        cmsg_groups |= 1;
 854                        size += sizeof(struct scatterlist);
 855                        break;
 856
 857                default:
 858                        return -EINVAL;
 859                }
 860
 861        }
 862
 863        size += ceil(data_len, PAGE_SIZE) * sizeof(struct scatterlist);
 864
 865        /* Ensure (DEST, MAP) are never used with (ARGS, ATOMIC) */
 866        if (cmsg_groups == 3)
 867                return -EINVAL;
 868
 869        return size;
 870}
 871
 872static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
 873                         struct msghdr *msg, int *allocated_mr)
 874{
 875        struct cmsghdr *cmsg;
 876        int ret = 0;
 877
 878        for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
 879                if (!CMSG_OK(msg, cmsg))
 880                        return -EINVAL;
 881
 882                if (cmsg->cmsg_level != SOL_RDS)
 883                        continue;
 884
 885                /* As a side effect, RDMA_DEST and RDMA_MAP will set
 886                 * rm->rdma.m_rdma_cookie and rm->rdma.m_rdma_mr.
 887                 */
 888                switch (cmsg->cmsg_type) {
 889                case RDS_CMSG_RDMA_ARGS:
 890                        ret = rds_cmsg_rdma_args(rs, rm, cmsg);
 891                        break;
 892
 893                case RDS_CMSG_RDMA_DEST:
 894                        ret = rds_cmsg_rdma_dest(rs, rm, cmsg);
 895                        break;
 896
 897                case RDS_CMSG_RDMA_MAP:
 898                        ret = rds_cmsg_rdma_map(rs, rm, cmsg);
 899                        if (!ret)
 900                                *allocated_mr = 1;
 901                        break;
 902                case RDS_CMSG_ATOMIC_CSWP:
 903                case RDS_CMSG_ATOMIC_FADD:
 904                case RDS_CMSG_MASKED_ATOMIC_CSWP:
 905                case RDS_CMSG_MASKED_ATOMIC_FADD:
 906                        ret = rds_cmsg_atomic(rs, rm, cmsg);
 907                        break;
 908
 909                default:
 910                        return -EINVAL;
 911                }
 912
 913                if (ret)
 914                        break;
 915        }
 916
 917        return ret;
 918}
 919
 920int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
 921                size_t payload_len)
 922{
 923        struct sock *sk = sock->sk;
 924        struct rds_sock *rs = rds_sk_to_rs(sk);
 925        struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name;
 926        __be32 daddr;
 927        __be16 dport;
 928        struct rds_message *rm = NULL;
 929        struct rds_connection *conn;
 930        int ret = 0;
 931        int queued = 0, allocated_mr = 0;
 932        int nonblock = msg->msg_flags & MSG_DONTWAIT;
 933        long timeo = sock_sndtimeo(sk, nonblock);
 934
 935        /* Mirror Linux UDP mirror of BSD error message compatibility */
 936        /* XXX: Perhaps MSG_MORE someday */
 937        if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) {
 938                ret = -EOPNOTSUPP;
 939                goto out;
 940        }
 941
 942        if (msg->msg_namelen) {
 943                /* XXX fail non-unicast destination IPs? */
 944                if (msg->msg_namelen < sizeof(*usin) || usin->sin_family != AF_INET) {
 945                        ret = -EINVAL;
 946                        goto out;
 947                }
 948                daddr = usin->sin_addr.s_addr;
 949                dport = usin->sin_port;
 950        } else {
 951                /* We only care about consistency with ->connect() */
 952                lock_sock(sk);
 953                daddr = rs->rs_conn_addr;
 954                dport = rs->rs_conn_port;
 955                release_sock(sk);
 956        }
 957
 958        /* racing with another thread binding seems ok here */
 959        if (daddr == 0 || rs->rs_bound_addr == 0) {
 960                ret = -ENOTCONN; /* XXX not a great errno */
 961                goto out;
 962        }
 963
 964        /* size of rm including all sgs */
 965        ret = rds_rm_size(msg, payload_len);
 966        if (ret < 0)
 967                goto out;
 968
 969        rm = rds_message_alloc(ret, GFP_KERNEL);
 970        if (!rm) {
 971                ret = -ENOMEM;
 972                goto out;
 973        }
 974
 975        /* Attach data to the rm */
 976        if (payload_len) {
 977                rm->data.op_sg = rds_message_alloc_sgs(rm, ceil(payload_len, PAGE_SIZE));
 978                if (!rm->data.op_sg) {
 979                        ret = -ENOMEM;
 980                        goto out;
 981                }
 982                ret = rds_message_copy_from_user(rm, msg->msg_iov, payload_len);
 983                if (ret)
 984                        goto out;
 985        }
 986        rm->data.op_active = 1;
 987
 988        rm->m_daddr = daddr;
 989
 990        /* rds_conn_create has a spinlock that runs with IRQ off.
 991         * Caching the conn in the socket helps a lot. */
 992        if (rs->rs_conn && rs->rs_conn->c_faddr == daddr)
 993                conn = rs->rs_conn;
 994        else {
 995                conn = rds_conn_create_outgoing(rs->rs_bound_addr, daddr,
 996                                        rs->rs_transport,
 997                                        sock->sk->sk_allocation);
 998                if (IS_ERR(conn)) {
 999                        ret = PTR_ERR(conn);
1000                        goto out;
1001                }
1002                rs->rs_conn = conn;
1003        }
1004
1005        /* Parse any control messages the user may have included. */
1006        ret = rds_cmsg_send(rs, rm, msg, &allocated_mr);
1007        if (ret)
1008                goto out;
1009
1010        if (rm->rdma.op_active && !conn->c_trans->xmit_rdma) {
1011                printk_ratelimited(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",
1012                               &rm->rdma, conn->c_trans->xmit_rdma);
1013                ret = -EOPNOTSUPP;
1014                goto out;
1015        }
1016
1017        if (rm->atomic.op_active && !conn->c_trans->xmit_atomic) {
1018                printk_ratelimited(KERN_NOTICE "atomic_op %p conn xmit_atomic %p\n",
1019                               &rm->atomic, conn->c_trans->xmit_atomic);
1020                ret = -EOPNOTSUPP;
1021                goto out;
1022        }
1023
1024        rds_conn_connect_if_down(conn);
1025
1026        ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);
1027        if (ret) {
1028                rs->rs_seen_congestion = 1;
1029                goto out;
1030        }
1031
1032        while (!rds_send_queue_rm(rs, conn, rm, rs->rs_bound_port,
1033                                  dport, &queued)) {
1034                rds_stats_inc(s_send_queue_full);
1035                /* XXX make sure this is reasonable */
1036                if (payload_len > rds_sk_sndbuf(rs)) {
1037                        ret = -EMSGSIZE;
1038                        goto out;
1039                }
1040                if (nonblock) {
1041                        ret = -EAGAIN;
1042                        goto out;
1043                }
1044
1045                timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
1046                                        rds_send_queue_rm(rs, conn, rm,
1047                                                          rs->rs_bound_port,
1048                                                          dport,
1049                                                          &queued),
1050                                        timeo);
1051                rdsdebug("sendmsg woke queued %d timeo %ld\n", queued, timeo);
1052                if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
1053                        continue;
1054
1055                ret = timeo;
1056                if (ret == 0)
1057                        ret = -ETIMEDOUT;
1058                goto out;
1059        }
1060
1061        /*
1062         * By now we've committed to the send.  We reuse rds_send_worker()
1063         * to retry sends in the rds thread if the transport asks us to.
1064         */
1065        rds_stats_inc(s_send_queued);
1066
1067        if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
1068                rds_send_xmit(conn);
1069
1070        rds_message_put(rm);
1071        return payload_len;
1072
1073out:
1074        /* If the user included a RDMA_MAP cmsg, we allocated a MR on the fly.
1075         * If the sendmsg goes through, we keep the MR. If it fails with EAGAIN
1076         * or in any other way, we need to destroy the MR again */
1077        if (allocated_mr)
1078                rds_rdma_unuse(rs, rds_rdma_cookie_key(rm->m_rdma_cookie), 1);
1079
1080        if (rm)
1081                rds_message_put(rm);
1082        return ret;
1083}
1084
1085/*
1086 * Reply to a ping packet.
1087 */
1088int
1089rds_send_pong(struct rds_connection *conn, __be16 dport)
1090{
1091        struct rds_message *rm;
1092        unsigned long flags;
1093        int ret = 0;
1094
1095        rm = rds_message_alloc(0, GFP_ATOMIC);
1096        if (!rm) {
1097                ret = -ENOMEM;
1098                goto out;
1099        }
1100
1101        rm->m_daddr = conn->c_faddr;
1102        rm->data.op_active = 1;
1103
1104        rds_conn_connect_if_down(conn);
1105
1106        ret = rds_cong_wait(conn->c_fcong, dport, 1, NULL);
1107        if (ret)
1108                goto out;
1109
1110        spin_lock_irqsave(&conn->c_lock, flags);
1111        list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
1112        set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
1113        rds_message_addref(rm);
1114        rm->m_inc.i_conn = conn;
1115
1116        rds_message_populate_header(&rm->m_inc.i_hdr, 0, dport,
1117                                    conn->c_next_tx_seq);
1118        conn->c_next_tx_seq++;
1119        spin_unlock_irqrestore(&conn->c_lock, flags);
1120
1121        rds_stats_inc(s_send_queued);
1122        rds_stats_inc(s_send_pong);
1123
1124        if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
1125                queue_delayed_work(rds_wq, &conn->c_send_w, 0);
1126
1127        rds_message_put(rm);
1128        return 0;
1129
1130out:
1131        if (rm)
1132                rds_message_put(rm);
1133        return ret;
1134}
1135
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