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 static void rds_send_remove_from_sock(struct list_head *messages, int status); 56 57 /* 58 * Reset the send state. Callers must ensure that this doesn't race with 59 * rds_send_xmit(). 60 */ 61 void rds_send_reset(struct rds_connection *conn) 62 { 63 struct rds_message *rm, *tmp; 64 unsigned long flags; 65 66 if (conn->c_xmit_rm) { 67 rm = conn->c_xmit_rm; 68 conn->c_xmit_rm = NULL; 69 /* Tell the user the RDMA op is no longer mapped by the 70 * transport. This isn't entirely true (it's flushed out 71 * independently) but as the connection is down, there's 72 * no ongoing RDMA to/from that memory */ 73 rds_message_unmapped(rm); 74 rds_message_put(rm); 75 } 76 77 conn->c_xmit_sg = 0; 78 conn->c_xmit_hdr_off = 0; 79 conn->c_xmit_data_off = 0; 80 conn->c_xmit_atomic_sent = 0; 81 conn->c_xmit_rdma_sent = 0; 82 conn->c_xmit_data_sent = 0; 83 84 conn->c_map_queued = 0; 85 86 conn->c_unacked_packets = rds_sysctl_max_unacked_packets; 87 conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes; 88 89 /* Mark messages as retransmissions, and move them to the send q */ 90 spin_lock_irqsave(&conn->c_lock, flags); 91 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) { 92 set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags); 93 set_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags); 94 } 95 list_splice_init(&conn->c_retrans, &conn->c_send_queue); 96 spin_unlock_irqrestore(&conn->c_lock, flags); 97 } 98 99 static int acquire_in_xmit(struct rds_connection *conn) 100 { 101 return test_and_set_bit(RDS_IN_XMIT, &conn->c_flags) == 0; 102 } 103 104 static void release_in_xmit(struct rds_connection *conn) 105 { 106 clear_bit(RDS_IN_XMIT, &conn->c_flags); 107 smp_mb__after_clear_bit(); 108 /* 109 * We don't use wait_on_bit()/wake_up_bit() because our waking is in a 110 * hot path and finding waiters is very rare. We don't want to walk 111 * the system-wide hashed waitqueue buckets in the fast path only to 112 * almost never find waiters. 113 */ 114 if (waitqueue_active(&conn->c_waitq)) 115 wake_up_all(&conn->c_waitq); 116 } 117 118 /* 119 * We're making the concious trade-off here to only send one message 120 * down the connection at a time. 121 * Pro: 122 * - tx queueing is a simple fifo list 123 * - reassembly is optional and easily done by transports per conn 124 * - no per flow rx lookup at all, straight to the socket 125 * - less per-frag memory and wire overhead 126 * Con: 127 * - queued acks can be delayed behind large messages 128 * Depends: 129 * - small message latency is higher behind queued large messages 130 * - large message latency isn't starved by intervening small sends 131 */ 132 int rds_send_xmit(struct rds_connection *conn) 133 { 134 struct rds_message *rm; 135 unsigned long flags; 136 unsigned int tmp; 137 struct scatterlist *sg; 138 int ret = 0; 139 LIST_HEAD(to_be_dropped); 140 141 restart: 142 143 /* 144 * sendmsg calls here after having queued its message on the send 145 * queue. We only have one task feeding the connection at a time. If 146 * another thread is already feeding the queue then we back off. This 147 * avoids blocking the caller and trading per-connection data between 148 * caches per message. 149 */ 150 if (!acquire_in_xmit(conn)) { 151 rds_stats_inc(s_send_lock_contention); 152 ret = -ENOMEM; 153 goto out; 154 } 155 156 /* 157 * rds_conn_shutdown() sets the conn state and then tests RDS_IN_XMIT, 158 * we do the opposite to avoid races. 159 */ 160 if (!rds_conn_up(conn)) { 161 release_in_xmit(conn); 162 ret = 0; 163 goto out; 164 } 165 166 if (conn->c_trans->xmit_prepare) 167 conn->c_trans->xmit_prepare(conn); 168 169 /* 170 * spin trying to push headers and data down the connection until 171 * the connection doesn't make forward progress. 172 */ 173 while (1) { 174 175 rm = conn->c_xmit_rm; 176 177 /* 178 * If between sending messages, we can send a pending congestion 179 * map update. 180 */ 181 if (!rm && test_and_clear_bit(0, &conn->c_map_queued)) { 182 rm = rds_cong_update_alloc(conn); 183 if (IS_ERR(rm)) { 184 ret = PTR_ERR(rm); 185 break; 186 } 187 rm->data.op_active = 1; 188 189 conn->c_xmit_rm = rm; 190 } 191 192 /* 193 * If not already working on one, grab the next message. 194 * 195 * c_xmit_rm holds a ref while we're sending this message down 196 * the connction. We can use this ref while holding the 197 * send_sem.. rds_send_reset() is serialized with it. 198 */ 199 if (!rm) { 200 unsigned int len; 201 202 spin_lock_irqsave(&conn->c_lock, flags); 203 204 if (!list_empty(&conn->c_send_queue)) { 205 rm = list_entry(conn->c_send_queue.next, 206 struct rds_message, 207 m_conn_item); 208 rds_message_addref(rm); 209 210 /* 211 * Move the message from the send queue to the retransmit 212 * list right away. 213 */ 214 list_move_tail(&rm->m_conn_item, &conn->c_retrans); 215 } 216 217 spin_unlock_irqrestore(&conn->c_lock, flags); 218 219 if (!rm) 220 break; 221 222 /* Unfortunately, the way Infiniband deals with 223 * RDMA to a bad MR key is by moving the entire 224 * queue pair to error state. We cold possibly 225 * recover from that, but right now we drop the 226 * connection. 227 * Therefore, we never retransmit messages with RDMA ops. 228 */ 229 if (rm->rdma.op_active && 230 test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) { 231 spin_lock_irqsave(&conn->c_lock, flags); 232 if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) 233 list_move(&rm->m_conn_item, &to_be_dropped); 234 spin_unlock_irqrestore(&conn->c_lock, flags); 235 continue; 236 } 237 238 /* Require an ACK every once in a while */ 239 len = ntohl(rm->m_inc.i_hdr.h_len); 240 if (conn->c_unacked_packets == 0 || 241 conn->c_unacked_bytes < len) { 242 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags); 243 244 conn->c_unacked_packets = rds_sysctl_max_unacked_packets; 245 conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes; 246 rds_stats_inc(s_send_ack_required); 247 } else { 248 conn->c_unacked_bytes -= len; 249 conn->c_unacked_packets--; 250 } 251 252 conn->c_xmit_rm = rm; 253 } 254 255 /* The transport either sends the whole rdma or none of it */ 256 if (rm->rdma.op_active && !conn->c_xmit_rdma_sent) { 257 rm->m_final_op = &rm->rdma; 258 ret = conn->c_trans->xmit_rdma(conn, &rm->rdma); 259 if (ret) 260 break; 261 conn->c_xmit_rdma_sent = 1; 262 263 /* The transport owns the mapped memory for now. 264 * You can't unmap it while it's on the send queue */ 265 set_bit(RDS_MSG_MAPPED, &rm->m_flags); 266 } 267 268 if (rm->atomic.op_active && !conn->c_xmit_atomic_sent) { 269 rm->m_final_op = &rm->atomic; 270 ret = conn->c_trans->xmit_atomic(conn, &rm->atomic); 271 if (ret) 272 break; 273 conn->c_xmit_atomic_sent = 1; 274 275 /* The transport owns the mapped memory for now. 276 * You can't unmap it while it's on the send queue */ 277 set_bit(RDS_MSG_MAPPED, &rm->m_flags); 278 } 279 280 /* 281 * A number of cases require an RDS header to be sent 282 * even if there is no data. 283 * We permit 0-byte sends; rds-ping depends on this. 284 * However, if there are exclusively attached silent ops, 285 * we skip the hdr/data send, to enable silent operation. 286 */ 287 if (rm->data.op_nents == 0) { 288 int ops_present; 289 int all_ops_are_silent = 1; 290 291 ops_present = (rm->atomic.op_active || rm->rdma.op_active); 292 if (rm->atomic.op_active && !rm->atomic.op_silent) 293 all_ops_are_silent = 0; 294 if (rm->rdma.op_active && !rm->rdma.op_silent) 295 all_ops_are_silent = 0; 296 297 if (ops_present && all_ops_are_silent 298 && !rm->m_rdma_cookie) 299 rm->data.op_active = 0; 300 } 301 302 if (rm->data.op_active && !conn->c_xmit_data_sent) { 303 rm->m_final_op = &rm->data; 304 ret = conn->c_trans->xmit(conn, rm, 305 conn->c_xmit_hdr_off, 306 conn->c_xmit_sg, 307 conn->c_xmit_data_off); 308 if (ret <= 0) 309 break; 310 311 if (conn->c_xmit_hdr_off < sizeof(struct rds_header)) { 312 tmp = min_t(int, ret, 313 sizeof(struct rds_header) - 314 conn->c_xmit_hdr_off); 315 conn->c_xmit_hdr_off += tmp; 316 ret -= tmp; 317 } 318 319 sg = &rm->data.op_sg[conn->c_xmit_sg]; 320 while (ret) { 321 tmp = min_t(int, ret, sg->length - 322 conn->c_xmit_data_off); 323 conn->c_xmit_data_off += tmp; 324 ret -= tmp; 325 if (conn->c_xmit_data_off == sg->length) { 326 conn->c_xmit_data_off = 0; 327 sg++; 328 conn->c_xmit_sg++; 329 BUG_ON(ret != 0 && 330 conn->c_xmit_sg == rm->data.op_nents); 331 } 332 } 333 334 if (conn->c_xmit_hdr_off == sizeof(struct rds_header) && 335 (conn->c_xmit_sg == rm->data.op_nents)) 336 conn->c_xmit_data_sent = 1; 337 } 338 339 /* 340 * A rm will only take multiple times through this loop 341 * if there is a data op. Thus, if the data is sent (or there was 342 * none), then we're done with the rm. 343 */ 344 if (!rm->data.op_active || conn->c_xmit_data_sent) { 345 conn->c_xmit_rm = NULL; 346 conn->c_xmit_sg = 0; 347 conn->c_xmit_hdr_off = 0; 348 conn->c_xmit_data_off = 0; 349 conn->c_xmit_rdma_sent = 0; 350 conn->c_xmit_atomic_sent = 0; 351 conn->c_xmit_data_sent = 0; 352 353 rds_message_put(rm); 354 } 355 } 356 357 if (conn->c_trans->xmit_complete) 358 conn->c_trans->xmit_complete(conn); 359 360 release_in_xmit(conn); 361 362 /* Nuke any messages we decided not to retransmit. */ 363 if (!list_empty(&to_be_dropped)) { 364 /* irqs on here, so we can put(), unlike above */ 365 list_for_each_entry(rm, &to_be_dropped, m_conn_item) 366 rds_message_put(rm); 367 rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED); 368 } 369 370 /* 371 * Other senders can queue a message after we last test the send queue 372 * but before we clear RDS_IN_XMIT. In that case they'd back off and 373 * not try and send their newly queued message. We need to check the 374 * send queue after having cleared RDS_IN_XMIT so that their message 375 * doesn't get stuck on the send queue. 376 * 377 * If the transport cannot continue (i.e ret != 0), then it must 378 * call us when more room is available, such as from the tx 379 * completion handler. 380 */ 381 if (ret == 0) { 382 smp_mb(); 383 if (!list_empty(&conn->c_send_queue)) { 384 rds_stats_inc(s_send_lock_queue_raced); 385 goto restart; 386 } 387 } 388 out: 389 return ret; 390 } 391 392 static void rds_send_sndbuf_remove(struct rds_sock *rs, struct rds_message *rm) 393 { 394 u32 len = be32_to_cpu(rm->m_inc.i_hdr.h_len); 395 396 assert_spin_locked(&rs->rs_lock); 397 398 BUG_ON(rs->rs_snd_bytes < len); 399 rs->rs_snd_bytes -= len; 400 401 if (rs->rs_snd_bytes == 0) 402 rds_stats_inc(s_send_queue_empty); 403 } 404 405 static inline int rds_send_is_acked(struct rds_message *rm, u64 ack, 406 is_acked_func is_acked) 407 { 408 if (is_acked) 409 return is_acked(rm, ack); 410 return be64_to_cpu(rm->m_inc.i_hdr.h_sequence) <= ack; 411 } 412 413 /* 414 * This is pretty similar to what happens below in the ACK 415 * handling code - except that we call here as soon as we get 416 * the IB send completion on the RDMA op and the accompanying 417 * message. 418 */ 419 void rds_rdma_send_complete(struct rds_message *rm, int status) 420 { 421 struct rds_sock *rs = NULL; 422 struct rm_rdma_op *ro; 423 struct rds_notifier *notifier; 424 unsigned long flags; 425 426 spin_lock_irqsave(&rm->m_rs_lock, flags); 427 428 ro = &rm->rdma; 429 if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) && 430 ro->op_active && ro->op_notify && ro->op_notifier) { 431 notifier = ro->op_notifier; 432 rs = rm->m_rs; 433 sock_hold(rds_rs_to_sk(rs)); 434 435 notifier->n_status = status; 436 spin_lock(&rs->rs_lock); 437 list_add_tail(¬ifier->n_list, &rs->rs_notify_queue); 438 spin_unlock(&rs->rs_lock); 439 440 ro->op_notifier = NULL; 441 } 442 443 spin_unlock_irqrestore(&rm->m_rs_lock, flags); 444 445 if (rs) { 446 rds_wake_sk_sleep(rs); 447 sock_put(rds_rs_to_sk(rs)); 448 } 449 } 450 EXPORT_SYMBOL_GPL(rds_rdma_send_complete); 451 452 /* 453 * Just like above, except looks at atomic op 454 */ 455 void rds_atomic_send_complete(struct rds_message *rm, int status) 456 { 457 struct rds_sock *rs = NULL; 458 struct rm_atomic_op *ao; 459 struct rds_notifier *notifier; 460 unsigned long flags; 461 462 spin_lock_irqsave(&rm->m_rs_lock, flags); 463 464 ao = &rm->atomic; 465 if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) 466 && ao->op_active && ao->op_notify && ao->op_notifier) { 467 notifier = ao->op_notifier; 468 rs = rm->m_rs; 469 sock_hold(rds_rs_to_sk(rs)); 470 471 notifier->n_status = status; 472 spin_lock(&rs->rs_lock); 473 list_add_tail(¬ifier->n_list, &rs->rs_notify_queue); 474 spin_unlock(&rs->rs_lock); 475 476 ao->op_notifier = NULL; 477 } 478 479 spin_unlock_irqrestore(&rm->m_rs_lock, flags); 480 481 if (rs) { 482 rds_wake_sk_sleep(rs); 483 sock_put(rds_rs_to_sk(rs)); 484 } 485 } 486 EXPORT_SYMBOL_GPL(rds_atomic_send_complete); 487 488 /* 489 * This is the same as rds_rdma_send_complete except we 490 * don't do any locking - we have all the ingredients (message, 491 * socket, socket lock) and can just move the notifier. 492 */ 493 static inline void 494 __rds_send_complete(struct rds_sock *rs, struct rds_message *rm, int status) 495 { 496 struct rm_rdma_op *ro; 497 struct rm_atomic_op *ao; 498 499 ro = &rm->rdma; 500 if (ro->op_active && ro->op_notify && ro->op_notifier) { 501 ro->op_notifier->n_status = status; 502 list_add_tail(&ro->op_notifier->n_list, &rs->rs_notify_queue); 503 ro->op_notifier = NULL; 504 } 505 506 ao = &rm->atomic; 507 if (ao->op_active && ao->op_notify && ao->op_notifier) { 508 ao->op_notifier->n_status = status; 509 list_add_tail(&ao->op_notifier->n_list, &rs->rs_notify_queue); 510 ao->op_notifier = NULL; 511 } 512 513 /* No need to wake the app - caller does this */ 514 } 515 516 /* 517 * This is called from the IB send completion when we detect 518 * a RDMA operation that failed with remote access error. 519 * So speed is not an issue here. 520 */ 521 struct rds_message *rds_send_get_message(struct rds_connection *conn, 522 struct rm_rdma_op *op) 523 { 524 struct rds_message *rm, *tmp, *found = NULL; 525 unsigned long flags; 526 527 spin_lock_irqsave(&conn->c_lock, flags); 528 529 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) { 530 if (&rm->rdma == op) { 531 atomic_inc(&rm->m_refcount); 532 found = rm; 533 goto out; 534 } 535 } 536 537 list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) { 538 if (&rm->rdma == op) { 539 atomic_inc(&rm->m_refcount); 540 found = rm; 541 break; 542 } 543 } 544 545 out: 546 spin_unlock_irqrestore(&conn->c_lock, flags); 547 548 return found; 549 } 550 EXPORT_SYMBOL_GPL(rds_send_get_message); 551 552 /* 553 * This removes messages from the socket's list if they're on it. The list 554 * argument must be private to the caller, we must be able to modify it 555 * without locks. The messages must have a reference held for their 556 * position on the list. This function will drop that reference after 557 * removing the messages from the 'messages' list regardless of if it found 558 * the messages on the socket list or not. 559 */ 560 static void rds_send_remove_from_sock(struct list_head *messages, int status) 561 { 562 unsigned long flags; 563 struct rds_sock *rs = NULL; 564 struct rds_message *rm; 565 566 while (!list_empty(messages)) { 567 int was_on_sock = 0; 568 569 rm = list_entry(messages->next, struct rds_message, 570 m_conn_item); 571 list_del_init(&rm->m_conn_item); 572 573 /* 574 * If we see this flag cleared then we're *sure* that someone 575 * else beat us to removing it from the sock. If we race 576 * with their flag update we'll get the lock and then really 577 * see that the flag has been cleared. 578 * 579 * The message spinlock makes sure nobody clears rm->m_rs 580 * while we're messing with it. It does not prevent the 581 * message from being removed from the socket, though. 582 */ 583 spin_lock_irqsave(&rm->m_rs_lock, flags); 584 if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) 585 goto unlock_and_drop; 586 587 if (rs != rm->m_rs) { 588 if (rs) { 589 rds_wake_sk_sleep(rs); 590 sock_put(rds_rs_to_sk(rs)); 591 } 592 rs = rm->m_rs; 593 sock_hold(rds_rs_to_sk(rs)); 594 } 595 spin_lock(&rs->rs_lock); 596 597 if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) { 598 struct rm_rdma_op *ro = &rm->rdma; 599 struct rds_notifier *notifier; 600 601 list_del_init(&rm->m_sock_item); 602 rds_send_sndbuf_remove(rs, rm); 603 604 if (ro->op_active && ro->op_notifier && 605 (ro->op_notify || (ro->op_recverr && status))) { 606 notifier = ro->op_notifier; 607 list_add_tail(¬ifier->n_list, 608 &rs->rs_notify_queue); 609 if (!notifier->n_status) 610 notifier->n_status = status; 611 rm->rdma.op_notifier = NULL; 612 } 613 was_on_sock = 1; 614 rm->m_rs = NULL; 615 } 616 spin_unlock(&rs->rs_lock); 617 618 unlock_and_drop: 619 spin_unlock_irqrestore(&rm->m_rs_lock, flags); 620 rds_message_put(rm); 621 if (was_on_sock) 622 rds_message_put(rm); 623 } 624 625 if (rs) { 626 rds_wake_sk_sleep(rs); 627 sock_put(rds_rs_to_sk(rs)); 628 } 629 } 630 631 /* 632 * Transports call here when they've determined that the receiver queued 633 * messages up to, and including, the given sequence number. Messages are 634 * moved to the retrans queue when rds_send_xmit picks them off the send 635 * queue. This means that in the TCP case, the message may not have been 636 * assigned the m_ack_seq yet - but that's fine as long as tcp_is_acked 637 * checks the RDS_MSG_HAS_ACK_SEQ bit. 638 * 639 * XXX It's not clear to me how this is safely serialized with socket 640 * destruction. Maybe it should bail if it sees SOCK_DEAD. 641 */ 642 void rds_send_drop_acked(struct rds_connection *conn, u64 ack, 643 is_acked_func is_acked) 644 { 645 struct rds_message *rm, *tmp; 646 unsigned long flags; 647 LIST_HEAD(list); 648 649 spin_lock_irqsave(&conn->c_lock, flags); 650 651 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) { 652 if (!rds_send_is_acked(rm, ack, is_acked)) 653 break; 654 655 list_move(&rm->m_conn_item, &list); 656 clear_bit(RDS_MSG_ON_CONN, &rm->m_flags); 657 } 658 659 /* order flag updates with spin locks */ 660 if (!list_empty(&list)) 661 smp_mb__after_clear_bit(); 662 663 spin_unlock_irqrestore(&conn->c_lock, flags); 664 665 /* now remove the messages from the sock list as needed */ 666 rds_send_remove_from_sock(&list, RDS_RDMA_SUCCESS); 667 } 668 EXPORT_SYMBOL_GPL(rds_send_drop_acked); 669 670 void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest) 671 { 672 struct rds_message *rm, *tmp; 673 struct rds_connection *conn; 674 unsigned long flags; 675 LIST_HEAD(list); 676 677 /* get all the messages we're dropping under the rs lock */ 678 spin_lock_irqsave(&rs->rs_lock, flags); 679 680 list_for_each_entry_safe(rm, tmp, &rs->rs_send_queue, m_sock_item) { 681 if (dest && (dest->sin_addr.s_addr != rm->m_daddr || 682 dest->sin_port != rm->m_inc.i_hdr.h_dport)) 683 continue; 684 685 list_move(&rm->m_sock_item, &list); 686 rds_send_sndbuf_remove(rs, rm); 687 clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags); 688 } 689 690 /* order flag updates with the rs lock */ 691 smp_mb__after_clear_bit(); 692 693 spin_unlock_irqrestore(&rs->rs_lock, flags); 694 695 if (list_empty(&list)) 696 return; 697 698 /* Remove the messages from the conn */ 699 list_for_each_entry(rm, &list, m_sock_item) { 700 701 conn = rm->m_inc.i_conn; 702 703 spin_lock_irqsave(&conn->c_lock, flags); 704 /* 705 * Maybe someone else beat us to removing rm from the conn. 706 * If we race with their flag update we'll get the lock and 707 * then really see that the flag has been cleared. 708 */ 709 if (!test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) { 710 spin_unlock_irqrestore(&conn->c_lock, flags); 711 continue; 712 } 713 list_del_init(&rm->m_conn_item); 714 spin_unlock_irqrestore(&conn->c_lock, flags); 715 716 /* 717 * Couldn't grab m_rs_lock in top loop (lock ordering), 718 * but we can now. 719 */ 720 spin_lock_irqsave(&rm->m_rs_lock, flags); 721 722 spin_lock(&rs->rs_lock); 723 __rds_send_complete(rs, rm, RDS_RDMA_CANCELED); 724 spin_unlock(&rs->rs_lock); 725 726 rm->m_rs = NULL; 727 spin_unlock_irqrestore(&rm->m_rs_lock, flags); 728 729 rds_message_put(rm); 730 } 731 732 rds_wake_sk_sleep(rs); 733 734 while (!list_empty(&list)) { 735 rm = list_entry(list.next, struct rds_message, m_sock_item); 736 list_del_init(&rm->m_sock_item); 737 738 rds_message_wait(rm); 739 rds_message_put(rm); 740 } 741 } 742 743 /* 744 * we only want this to fire once so we use the callers 'queued'. It's 745 * possible that another thread can race with us and remove the 746 * message from the flow with RDS_CANCEL_SENT_TO. 747 */ 748 static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn, 749 struct rds_message *rm, __be16 sport, 750 __be16 dport, int *queued) 751 { 752 unsigned long flags; 753 u32 len; 754 755 if (*queued) 756 goto out; 757 758 len = be32_to_cpu(rm->m_inc.i_hdr.h_len); 759 760 /* this is the only place which holds both the socket's rs_lock 761 * and the connection's c_lock */ 762 spin_lock_irqsave(&rs->rs_lock, flags); 763 764 /* 765 * If there is a little space in sndbuf, we don't queue anything, 766 * and userspace gets -EAGAIN. But poll() indicates there's send 767 * room. This can lead to bad behavior (spinning) if snd_bytes isn't 768 * freed up by incoming acks. So we check the *old* value of 769 * rs_snd_bytes here to allow the last msg to exceed the buffer, 770 * and poll() now knows no more data can be sent. 771 */ 772 if (rs->rs_snd_bytes < rds_sk_sndbuf(rs)) { 773 rs->rs_snd_bytes += len; 774 775 /* let recv side know we are close to send space exhaustion. 776 * This is probably not the optimal way to do it, as this 777 * means we set the flag on *all* messages as soon as our 778 * throughput hits a certain threshold. 779 */ 780 if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2) 781 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags); 782 783 list_add_tail(&rm->m_sock_item, &rs->rs_send_queue); 784 set_bit(RDS_MSG_ON_SOCK, &rm->m_flags); 785 rds_message_addref(rm); 786 rm->m_rs = rs; 787 788 /* The code ordering is a little weird, but we're 789 trying to minimize the time we hold c_lock */ 790 rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport, 0); 791 rm->m_inc.i_conn = conn; 792 rds_message_addref(rm); 793 794 spin_lock(&conn->c_lock); 795 rm->m_inc.i_hdr.h_sequence = cpu_to_be64(conn->c_next_tx_seq++); 796 list_add_tail(&rm->m_conn_item, &conn->c_send_queue); 797 set_bit(RDS_MSG_ON_CONN, &rm->m_flags); 798 spin_unlock(&conn->c_lock); 799 800 rdsdebug("queued msg %p len %d, rs %p bytes %d seq %llu\n", 801 rm, len, rs, rs->rs_snd_bytes, 802 (unsigned long long)be64_to_cpu(rm->m_inc.i_hdr.h_sequence)); 803 804 *queued = 1; 805 } 806 807 spin_unlock_irqrestore(&rs->rs_lock, flags); 808 out: 809 return *queued; 810 } 811 812 /* 813 * rds_message is getting to be quite complicated, and we'd like to allocate 814 * it all in one go. This figures out how big it needs to be up front. 815 */ 816 static int rds_rm_size(struct msghdr *msg, int data_len) 817 { 818 struct cmsghdr *cmsg; 819 int size = 0; 820 int cmsg_groups = 0; 821 int retval; 822 823 for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) { 824 if (!CMSG_OK(msg, cmsg)) 825 return -EINVAL; 826 827 if (cmsg->cmsg_level != SOL_RDS) 828 continue; 829 830 switch (cmsg->cmsg_type) { 831 case RDS_CMSG_RDMA_ARGS: 832 cmsg_groups |= 1; 833 retval = rds_rdma_extra_size(CMSG_DATA(cmsg)); 834 if (retval < 0) 835 return retval; 836 size += retval; 837 838 break; 839 840 case RDS_CMSG_RDMA_DEST: 841 case RDS_CMSG_RDMA_MAP: 842 cmsg_groups |= 2; 843 /* these are valid but do no add any size */ 844 break; 845 846 case RDS_CMSG_ATOMIC_CSWP: 847 case RDS_CMSG_ATOMIC_FADD: 848 case RDS_CMSG_MASKED_ATOMIC_CSWP: 849 case RDS_CMSG_MASKED_ATOMIC_FADD: 850 cmsg_groups |= 1; 851 size += sizeof(struct scatterlist); 852 break; 853 854 default: 855 return -EINVAL; 856 } 857 858 } 859 860 size += ceil(data_len, PAGE_SIZE) * sizeof(struct scatterlist); 861 862 /* Ensure (DEST, MAP) are never used with (ARGS, ATOMIC) */ 863 if (cmsg_groups == 3) 864 return -EINVAL; 865 866 return size; 867 } 868 869 static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm, 870 struct msghdr *msg, int *allocated_mr) 871 { 872 struct cmsghdr *cmsg; 873 int ret = 0; 874 875 for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) { 876 if (!CMSG_OK(msg, cmsg)) 877 return -EINVAL; 878 879 if (cmsg->cmsg_level != SOL_RDS) 880 continue; 881 882 /* As a side effect, RDMA_DEST and RDMA_MAP will set 883 * rm->rdma.m_rdma_cookie and rm->rdma.m_rdma_mr. 884 */ 885 switch (cmsg->cmsg_type) { 886 case RDS_CMSG_RDMA_ARGS: 887 ret = rds_cmsg_rdma_args(rs, rm, cmsg); 888 break; 889 890 case RDS_CMSG_RDMA_DEST: 891 ret = rds_cmsg_rdma_dest(rs, rm, cmsg); 892 break; 893 894 case RDS_CMSG_RDMA_MAP: 895 ret = rds_cmsg_rdma_map(rs, rm, cmsg); 896 if (!ret) 897 *allocated_mr = 1; 898 break; 899 case RDS_CMSG_ATOMIC_CSWP: 900 case RDS_CMSG_ATOMIC_FADD: 901 case RDS_CMSG_MASKED_ATOMIC_CSWP: 902 case RDS_CMSG_MASKED_ATOMIC_FADD: 903 ret = rds_cmsg_atomic(rs, rm, cmsg); 904 break; 905 906 default: 907 return -EINVAL; 908 } 909 910 if (ret) 911 break; 912 } 913 914 return ret; 915 } 916 917 int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg, 918 size_t payload_len) 919 { 920 struct sock *sk = sock->sk; 921 struct rds_sock *rs = rds_sk_to_rs(sk); 922 struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name; 923 __be32 daddr; 924 __be16 dport; 925 struct rds_message *rm = NULL; 926 struct rds_connection *conn; 927 int ret = 0; 928 int queued = 0, allocated_mr = 0; 929 int nonblock = msg->msg_flags & MSG_DONTWAIT; 930 long timeo = sock_sndtimeo(sk, nonblock); 931 932 /* Mirror Linux UDP mirror of BSD error message compatibility */ 933 /* XXX: Perhaps MSG_MORE someday */ 934 if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) { 935 printk(KERN_INFO "msg_flags 0x%08X\n", msg->msg_flags); 936 ret = -EOPNOTSUPP; 937 goto out; 938 } 939 940 if (msg->msg_namelen) { 941 /* XXX fail non-unicast destination IPs? */ 942 if (msg->msg_namelen < sizeof(*usin) || usin->sin_family != AF_INET) { 943 ret = -EINVAL; 944 goto out; 945 } 946 daddr = usin->sin_addr.s_addr; 947 dport = usin->sin_port; 948 } else { 949 /* We only care about consistency with ->connect() */ 950 lock_sock(sk); 951 daddr = rs->rs_conn_addr; 952 dport = rs->rs_conn_port; 953 release_sock(sk); 954 } 955 956 /* racing with another thread binding seems ok here */ 957 if (daddr == 0 || rs->rs_bound_addr == 0) { 958 ret = -ENOTCONN; /* XXX not a great errno */ 959 goto out; 960 } 961 962 /* size of rm including all sgs */ 963 ret = rds_rm_size(msg, payload_len); 964 if (ret < 0) 965 goto out; 966 967 rm = rds_message_alloc(ret, GFP_KERNEL); 968 if (!rm) { 969 ret = -ENOMEM; 970 goto out; 971 } 972 973 /* Attach data to the rm */ 974 if (payload_len) { 975 rm->data.op_sg = rds_message_alloc_sgs(rm, ceil(payload_len, PAGE_SIZE)); 976 if (!rm->data.op_sg) { 977 ret = -ENOMEM; 978 goto out; 979 } 980 ret = rds_message_copy_from_user(rm, msg->msg_iov, payload_len); 981 if (ret) 982 goto out; 983 } 984 rm->data.op_active = 1; 985 986 rm->m_daddr = daddr; 987 988 /* rds_conn_create has a spinlock that runs with IRQ off. 989 * Caching the conn in the socket helps a lot. */ 990 if (rs->rs_conn && rs->rs_conn->c_faddr == daddr) 991 conn = rs->rs_conn; 992 else { 993 conn = rds_conn_create_outgoing(rs->rs_bound_addr, daddr, 994 rs->rs_transport, 995 sock->sk->sk_allocation); 996 if (IS_ERR(conn)) { 997 ret = PTR_ERR(conn); 998 goto out; 999 } 1000 rs->rs_conn = conn; 1001 } 1002 1003 /* Parse any control messages the user may have included. */ 1004 ret = rds_cmsg_send(rs, rm, msg, &allocated_mr); 1005 if (ret) 1006 goto out; 1007 1008 if (rm->rdma.op_active && !conn->c_trans->xmit_rdma) { 1009 if (printk_ratelimit()) 1010 printk(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n", 1011 &rm->rdma, conn->c_trans->xmit_rdma); 1012 ret = -EOPNOTSUPP; 1013 goto out; 1014 } 1015 1016 if (rm->atomic.op_active && !conn->c_trans->xmit_atomic) { 1017 if (printk_ratelimit()) 1018 printk(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 1073 out: 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 */ 1088 int 1089 rds_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 rds_send_xmit(conn); 1126 1127 rds_message_put(rm); 1128 return 0; 1129 1130 out: 1131 if (rm) 1132 rds_message_put(rm); 1133 return ret; 1134 } 1135