xprt.c revision 43cedbf0e8dfb9c5610eb7985d5f21263e313802
1/* 2 * linux/net/sunrpc/xprt.c 3 * 4 * This is a generic RPC call interface supporting congestion avoidance, 5 * and asynchronous calls. 6 * 7 * The interface works like this: 8 * 9 * - When a process places a call, it allocates a request slot if 10 * one is available. Otherwise, it sleeps on the backlog queue 11 * (xprt_reserve). 12 * - Next, the caller puts together the RPC message, stuffs it into 13 * the request struct, and calls xprt_transmit(). 14 * - xprt_transmit sends the message and installs the caller on the 15 * transport's wait list. At the same time, if a reply is expected, 16 * it installs a timer that is run after the packet's timeout has 17 * expired. 18 * - When a packet arrives, the data_ready handler walks the list of 19 * pending requests for that transport. If a matching XID is found, the 20 * caller is woken up, and the timer removed. 21 * - When no reply arrives within the timeout interval, the timer is 22 * fired by the kernel and runs xprt_timer(). It either adjusts the 23 * timeout values (minor timeout) or wakes up the caller with a status 24 * of -ETIMEDOUT. 25 * - When the caller receives a notification from RPC that a reply arrived, 26 * it should release the RPC slot, and process the reply. 27 * If the call timed out, it may choose to retry the operation by 28 * adjusting the initial timeout value, and simply calling rpc_call 29 * again. 30 * 31 * Support for async RPC is done through a set of RPC-specific scheduling 32 * primitives that `transparently' work for processes as well as async 33 * tasks that rely on callbacks. 34 * 35 * Copyright (C) 1995-1997, Olaf Kirch <okir@monad.swb.de> 36 * 37 * Transport switch API copyright (C) 2005, Chuck Lever <cel@netapp.com> 38 */ 39 40#include <linux/module.h> 41 42#include <linux/types.h> 43#include <linux/interrupt.h> 44#include <linux/workqueue.h> 45#include <linux/net.h> 46#include <linux/ktime.h> 47 48#include <linux/sunrpc/clnt.h> 49#include <linux/sunrpc/metrics.h> 50#include <linux/sunrpc/bc_xprt.h> 51 52#include "sunrpc.h" 53 54/* 55 * Local variables 56 */ 57 58#ifdef RPC_DEBUG 59# define RPCDBG_FACILITY RPCDBG_XPRT 60#endif 61 62/* 63 * Local functions 64 */ 65static void xprt_request_init(struct rpc_task *, struct rpc_xprt *); 66static void xprt_connect_status(struct rpc_task *task); 67static int __xprt_get_cong(struct rpc_xprt *, struct rpc_task *); 68 69static DEFINE_SPINLOCK(xprt_list_lock); 70static LIST_HEAD(xprt_list); 71 72/* 73 * The transport code maintains an estimate on the maximum number of out- 74 * standing RPC requests, using a smoothed version of the congestion 75 * avoidance implemented in 44BSD. This is basically the Van Jacobson 76 * congestion algorithm: If a retransmit occurs, the congestion window is 77 * halved; otherwise, it is incremented by 1/cwnd when 78 * 79 * - a reply is received and 80 * - a full number of requests are outstanding and 81 * - the congestion window hasn't been updated recently. 82 */ 83#define RPC_CWNDSHIFT (8U) 84#define RPC_CWNDSCALE (1U << RPC_CWNDSHIFT) 85#define RPC_INITCWND RPC_CWNDSCALE 86#define RPC_MAXCWND(xprt) ((xprt)->max_reqs << RPC_CWNDSHIFT) 87 88#define RPCXPRT_CONGESTED(xprt) ((xprt)->cong >= (xprt)->cwnd) 89 90/** 91 * xprt_register_transport - register a transport implementation 92 * @transport: transport to register 93 * 94 * If a transport implementation is loaded as a kernel module, it can 95 * call this interface to make itself known to the RPC client. 96 * 97 * Returns: 98 * 0: transport successfully registered 99 * -EEXIST: transport already registered 100 * -EINVAL: transport module being unloaded 101 */ 102int xprt_register_transport(struct xprt_class *transport) 103{ 104 struct xprt_class *t; 105 int result; 106 107 result = -EEXIST; 108 spin_lock(&xprt_list_lock); 109 list_for_each_entry(t, &xprt_list, list) { 110 /* don't register the same transport class twice */ 111 if (t->ident == transport->ident) 112 goto out; 113 } 114 115 list_add_tail(&transport->list, &xprt_list); 116 printk(KERN_INFO "RPC: Registered %s transport module.\n", 117 transport->name); 118 result = 0; 119 120out: 121 spin_unlock(&xprt_list_lock); 122 return result; 123} 124EXPORT_SYMBOL_GPL(xprt_register_transport); 125 126/** 127 * xprt_unregister_transport - unregister a transport implementation 128 * @transport: transport to unregister 129 * 130 * Returns: 131 * 0: transport successfully unregistered 132 * -ENOENT: transport never registered 133 */ 134int xprt_unregister_transport(struct xprt_class *transport) 135{ 136 struct xprt_class *t; 137 int result; 138 139 result = 0; 140 spin_lock(&xprt_list_lock); 141 list_for_each_entry(t, &xprt_list, list) { 142 if (t == transport) { 143 printk(KERN_INFO 144 "RPC: Unregistered %s transport module.\n", 145 transport->name); 146 list_del_init(&transport->list); 147 goto out; 148 } 149 } 150 result = -ENOENT; 151 152out: 153 spin_unlock(&xprt_list_lock); 154 return result; 155} 156EXPORT_SYMBOL_GPL(xprt_unregister_transport); 157 158/** 159 * xprt_load_transport - load a transport implementation 160 * @transport_name: transport to load 161 * 162 * Returns: 163 * 0: transport successfully loaded 164 * -ENOENT: transport module not available 165 */ 166int xprt_load_transport(const char *transport_name) 167{ 168 struct xprt_class *t; 169 int result; 170 171 result = 0; 172 spin_lock(&xprt_list_lock); 173 list_for_each_entry(t, &xprt_list, list) { 174 if (strcmp(t->name, transport_name) == 0) { 175 spin_unlock(&xprt_list_lock); 176 goto out; 177 } 178 } 179 spin_unlock(&xprt_list_lock); 180 result = request_module("xprt%s", transport_name); 181out: 182 return result; 183} 184EXPORT_SYMBOL_GPL(xprt_load_transport); 185 186/** 187 * xprt_reserve_xprt - serialize write access to transports 188 * @task: task that is requesting access to the transport 189 * 190 * This prevents mixing the payload of separate requests, and prevents 191 * transport connects from colliding with writes. No congestion control 192 * is provided. 193 */ 194int xprt_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task) 195{ 196 struct rpc_rqst *req = task->tk_rqstp; 197 198 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) { 199 if (task == xprt->snd_task) 200 return 1; 201 goto out_sleep; 202 } 203 xprt->snd_task = task; 204 if (req != NULL) { 205 req->rq_bytes_sent = 0; 206 req->rq_ntrans++; 207 } 208 209 return 1; 210 211out_sleep: 212 dprintk("RPC: %5u failed to lock transport %p\n", 213 task->tk_pid, xprt); 214 task->tk_timeout = 0; 215 task->tk_status = -EAGAIN; 216 if (req != NULL && req->rq_ntrans) 217 rpc_sleep_on(&xprt->resend, task, NULL); 218 else 219 rpc_sleep_on(&xprt->sending, task, NULL); 220 return 0; 221} 222EXPORT_SYMBOL_GPL(xprt_reserve_xprt); 223 224static void xprt_clear_locked(struct rpc_xprt *xprt) 225{ 226 xprt->snd_task = NULL; 227 if (!test_bit(XPRT_CLOSE_WAIT, &xprt->state) || xprt->shutdown) { 228 smp_mb__before_clear_bit(); 229 clear_bit(XPRT_LOCKED, &xprt->state); 230 smp_mb__after_clear_bit(); 231 } else 232 queue_work(rpciod_workqueue, &xprt->task_cleanup); 233} 234 235/* 236 * xprt_reserve_xprt_cong - serialize write access to transports 237 * @task: task that is requesting access to the transport 238 * 239 * Same as xprt_reserve_xprt, but Van Jacobson congestion control is 240 * integrated into the decision of whether a request is allowed to be 241 * woken up and given access to the transport. 242 */ 243int xprt_reserve_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task) 244{ 245 struct rpc_rqst *req = task->tk_rqstp; 246 247 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) { 248 if (task == xprt->snd_task) 249 return 1; 250 goto out_sleep; 251 } 252 if (req == NULL) { 253 xprt->snd_task = task; 254 return 1; 255 } 256 if (__xprt_get_cong(xprt, task)) { 257 xprt->snd_task = task; 258 req->rq_bytes_sent = 0; 259 req->rq_ntrans++; 260 return 1; 261 } 262 xprt_clear_locked(xprt); 263out_sleep: 264 dprintk("RPC: %5u failed to lock transport %p\n", task->tk_pid, xprt); 265 task->tk_timeout = 0; 266 task->tk_status = -EAGAIN; 267 if (req != NULL && req->rq_ntrans) 268 rpc_sleep_on(&xprt->resend, task, NULL); 269 else 270 rpc_sleep_on(&xprt->sending, task, NULL); 271 return 0; 272} 273EXPORT_SYMBOL_GPL(xprt_reserve_xprt_cong); 274 275static inline int xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task) 276{ 277 int retval; 278 279 spin_lock_bh(&xprt->transport_lock); 280 retval = xprt->ops->reserve_xprt(xprt, task); 281 spin_unlock_bh(&xprt->transport_lock); 282 return retval; 283} 284 285static void __xprt_lock_write_next(struct rpc_xprt *xprt) 286{ 287 struct rpc_task *task; 288 struct rpc_rqst *req; 289 290 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) 291 return; 292 293 task = rpc_wake_up_next(&xprt->resend); 294 if (!task) { 295 task = rpc_wake_up_next(&xprt->sending); 296 if (task == NULL) 297 goto out_unlock; 298 } 299 300 req = task->tk_rqstp; 301 xprt->snd_task = task; 302 if (req) { 303 req->rq_bytes_sent = 0; 304 req->rq_ntrans++; 305 } 306 return; 307 308out_unlock: 309 xprt_clear_locked(xprt); 310} 311 312static void __xprt_lock_write_next_cong(struct rpc_xprt *xprt) 313{ 314 struct rpc_task *task; 315 struct rpc_rqst *req; 316 317 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) 318 return; 319 if (RPCXPRT_CONGESTED(xprt)) 320 goto out_unlock; 321 task = rpc_wake_up_next(&xprt->resend); 322 if (!task) { 323 task = rpc_wake_up_next(&xprt->sending); 324 if (task == NULL) 325 goto out_unlock; 326 } 327 328 req = task->tk_rqstp; 329 if (req == NULL) { 330 xprt->snd_task = task; 331 return; 332 } 333 if (__xprt_get_cong(xprt, task)) { 334 xprt->snd_task = task; 335 req->rq_bytes_sent = 0; 336 req->rq_ntrans++; 337 return; 338 } 339out_unlock: 340 xprt_clear_locked(xprt); 341} 342 343/** 344 * xprt_release_xprt - allow other requests to use a transport 345 * @xprt: transport with other tasks potentially waiting 346 * @task: task that is releasing access to the transport 347 * 348 * Note that "task" can be NULL. No congestion control is provided. 349 */ 350void xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task) 351{ 352 if (xprt->snd_task == task) { 353 xprt_clear_locked(xprt); 354 __xprt_lock_write_next(xprt); 355 } 356} 357EXPORT_SYMBOL_GPL(xprt_release_xprt); 358 359/** 360 * xprt_release_xprt_cong - allow other requests to use a transport 361 * @xprt: transport with other tasks potentially waiting 362 * @task: task that is releasing access to the transport 363 * 364 * Note that "task" can be NULL. Another task is awoken to use the 365 * transport if the transport's congestion window allows it. 366 */ 367void xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task) 368{ 369 if (xprt->snd_task == task) { 370 xprt_clear_locked(xprt); 371 __xprt_lock_write_next_cong(xprt); 372 } 373} 374EXPORT_SYMBOL_GPL(xprt_release_xprt_cong); 375 376static inline void xprt_release_write(struct rpc_xprt *xprt, struct rpc_task *task) 377{ 378 spin_lock_bh(&xprt->transport_lock); 379 xprt->ops->release_xprt(xprt, task); 380 spin_unlock_bh(&xprt->transport_lock); 381} 382 383/* 384 * Van Jacobson congestion avoidance. Check if the congestion window 385 * overflowed. Put the task to sleep if this is the case. 386 */ 387static int 388__xprt_get_cong(struct rpc_xprt *xprt, struct rpc_task *task) 389{ 390 struct rpc_rqst *req = task->tk_rqstp; 391 392 if (req->rq_cong) 393 return 1; 394 dprintk("RPC: %5u xprt_cwnd_limited cong = %lu cwnd = %lu\n", 395 task->tk_pid, xprt->cong, xprt->cwnd); 396 if (RPCXPRT_CONGESTED(xprt)) 397 return 0; 398 req->rq_cong = 1; 399 xprt->cong += RPC_CWNDSCALE; 400 return 1; 401} 402 403/* 404 * Adjust the congestion window, and wake up the next task 405 * that has been sleeping due to congestion 406 */ 407static void 408__xprt_put_cong(struct rpc_xprt *xprt, struct rpc_rqst *req) 409{ 410 if (!req->rq_cong) 411 return; 412 req->rq_cong = 0; 413 xprt->cong -= RPC_CWNDSCALE; 414 __xprt_lock_write_next_cong(xprt); 415} 416 417/** 418 * xprt_release_rqst_cong - housekeeping when request is complete 419 * @task: RPC request that recently completed 420 * 421 * Useful for transports that require congestion control. 422 */ 423void xprt_release_rqst_cong(struct rpc_task *task) 424{ 425 __xprt_put_cong(task->tk_xprt, task->tk_rqstp); 426} 427EXPORT_SYMBOL_GPL(xprt_release_rqst_cong); 428 429/** 430 * xprt_adjust_cwnd - adjust transport congestion window 431 * @task: recently completed RPC request used to adjust window 432 * @result: result code of completed RPC request 433 * 434 * We use a time-smoothed congestion estimator to avoid heavy oscillation. 435 */ 436void xprt_adjust_cwnd(struct rpc_task *task, int result) 437{ 438 struct rpc_rqst *req = task->tk_rqstp; 439 struct rpc_xprt *xprt = task->tk_xprt; 440 unsigned long cwnd = xprt->cwnd; 441 442 if (result >= 0 && cwnd <= xprt->cong) { 443 /* The (cwnd >> 1) term makes sure 444 * the result gets rounded properly. */ 445 cwnd += (RPC_CWNDSCALE * RPC_CWNDSCALE + (cwnd >> 1)) / cwnd; 446 if (cwnd > RPC_MAXCWND(xprt)) 447 cwnd = RPC_MAXCWND(xprt); 448 __xprt_lock_write_next_cong(xprt); 449 } else if (result == -ETIMEDOUT) { 450 cwnd >>= 1; 451 if (cwnd < RPC_CWNDSCALE) 452 cwnd = RPC_CWNDSCALE; 453 } 454 dprintk("RPC: cong %ld, cwnd was %ld, now %ld\n", 455 xprt->cong, xprt->cwnd, cwnd); 456 xprt->cwnd = cwnd; 457 __xprt_put_cong(xprt, req); 458} 459EXPORT_SYMBOL_GPL(xprt_adjust_cwnd); 460 461/** 462 * xprt_wake_pending_tasks - wake all tasks on a transport's pending queue 463 * @xprt: transport with waiting tasks 464 * @status: result code to plant in each task before waking it 465 * 466 */ 467void xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status) 468{ 469 if (status < 0) 470 rpc_wake_up_status(&xprt->pending, status); 471 else 472 rpc_wake_up(&xprt->pending); 473} 474EXPORT_SYMBOL_GPL(xprt_wake_pending_tasks); 475 476/** 477 * xprt_wait_for_buffer_space - wait for transport output buffer to clear 478 * @task: task to be put to sleep 479 * @action: function pointer to be executed after wait 480 */ 481void xprt_wait_for_buffer_space(struct rpc_task *task, rpc_action action) 482{ 483 struct rpc_rqst *req = task->tk_rqstp; 484 struct rpc_xprt *xprt = req->rq_xprt; 485 486 task->tk_timeout = req->rq_timeout; 487 rpc_sleep_on(&xprt->pending, task, action); 488} 489EXPORT_SYMBOL_GPL(xprt_wait_for_buffer_space); 490 491/** 492 * xprt_write_space - wake the task waiting for transport output buffer space 493 * @xprt: transport with waiting tasks 494 * 495 * Can be called in a soft IRQ context, so xprt_write_space never sleeps. 496 */ 497void xprt_write_space(struct rpc_xprt *xprt) 498{ 499 if (unlikely(xprt->shutdown)) 500 return; 501 502 spin_lock_bh(&xprt->transport_lock); 503 if (xprt->snd_task) { 504 dprintk("RPC: write space: waking waiting task on " 505 "xprt %p\n", xprt); 506 rpc_wake_up_queued_task(&xprt->pending, xprt->snd_task); 507 } 508 spin_unlock_bh(&xprt->transport_lock); 509} 510EXPORT_SYMBOL_GPL(xprt_write_space); 511 512/** 513 * xprt_set_retrans_timeout_def - set a request's retransmit timeout 514 * @task: task whose timeout is to be set 515 * 516 * Set a request's retransmit timeout based on the transport's 517 * default timeout parameters. Used by transports that don't adjust 518 * the retransmit timeout based on round-trip time estimation. 519 */ 520void xprt_set_retrans_timeout_def(struct rpc_task *task) 521{ 522 task->tk_timeout = task->tk_rqstp->rq_timeout; 523} 524EXPORT_SYMBOL_GPL(xprt_set_retrans_timeout_def); 525 526/* 527 * xprt_set_retrans_timeout_rtt - set a request's retransmit timeout 528 * @task: task whose timeout is to be set 529 * 530 * Set a request's retransmit timeout using the RTT estimator. 531 */ 532void xprt_set_retrans_timeout_rtt(struct rpc_task *task) 533{ 534 int timer = task->tk_msg.rpc_proc->p_timer; 535 struct rpc_clnt *clnt = task->tk_client; 536 struct rpc_rtt *rtt = clnt->cl_rtt; 537 struct rpc_rqst *req = task->tk_rqstp; 538 unsigned long max_timeout = clnt->cl_timeout->to_maxval; 539 540 task->tk_timeout = rpc_calc_rto(rtt, timer); 541 task->tk_timeout <<= rpc_ntimeo(rtt, timer) + req->rq_retries; 542 if (task->tk_timeout > max_timeout || task->tk_timeout == 0) 543 task->tk_timeout = max_timeout; 544} 545EXPORT_SYMBOL_GPL(xprt_set_retrans_timeout_rtt); 546 547static void xprt_reset_majortimeo(struct rpc_rqst *req) 548{ 549 const struct rpc_timeout *to = req->rq_task->tk_client->cl_timeout; 550 551 req->rq_majortimeo = req->rq_timeout; 552 if (to->to_exponential) 553 req->rq_majortimeo <<= to->to_retries; 554 else 555 req->rq_majortimeo += to->to_increment * to->to_retries; 556 if (req->rq_majortimeo > to->to_maxval || req->rq_majortimeo == 0) 557 req->rq_majortimeo = to->to_maxval; 558 req->rq_majortimeo += jiffies; 559} 560 561/** 562 * xprt_adjust_timeout - adjust timeout values for next retransmit 563 * @req: RPC request containing parameters to use for the adjustment 564 * 565 */ 566int xprt_adjust_timeout(struct rpc_rqst *req) 567{ 568 struct rpc_xprt *xprt = req->rq_xprt; 569 const struct rpc_timeout *to = req->rq_task->tk_client->cl_timeout; 570 int status = 0; 571 572 if (time_before(jiffies, req->rq_majortimeo)) { 573 if (to->to_exponential) 574 req->rq_timeout <<= 1; 575 else 576 req->rq_timeout += to->to_increment; 577 if (to->to_maxval && req->rq_timeout >= to->to_maxval) 578 req->rq_timeout = to->to_maxval; 579 req->rq_retries++; 580 } else { 581 req->rq_timeout = to->to_initval; 582 req->rq_retries = 0; 583 xprt_reset_majortimeo(req); 584 /* Reset the RTT counters == "slow start" */ 585 spin_lock_bh(&xprt->transport_lock); 586 rpc_init_rtt(req->rq_task->tk_client->cl_rtt, to->to_initval); 587 spin_unlock_bh(&xprt->transport_lock); 588 status = -ETIMEDOUT; 589 } 590 591 if (req->rq_timeout == 0) { 592 printk(KERN_WARNING "xprt_adjust_timeout: rq_timeout = 0!\n"); 593 req->rq_timeout = 5 * HZ; 594 } 595 return status; 596} 597 598static void xprt_autoclose(struct work_struct *work) 599{ 600 struct rpc_xprt *xprt = 601 container_of(work, struct rpc_xprt, task_cleanup); 602 603 xprt->ops->close(xprt); 604 clear_bit(XPRT_CLOSE_WAIT, &xprt->state); 605 xprt_release_write(xprt, NULL); 606} 607 608/** 609 * xprt_disconnect_done - mark a transport as disconnected 610 * @xprt: transport to flag for disconnect 611 * 612 */ 613void xprt_disconnect_done(struct rpc_xprt *xprt) 614{ 615 dprintk("RPC: disconnected transport %p\n", xprt); 616 spin_lock_bh(&xprt->transport_lock); 617 xprt_clear_connected(xprt); 618 xprt_wake_pending_tasks(xprt, -EAGAIN); 619 spin_unlock_bh(&xprt->transport_lock); 620} 621EXPORT_SYMBOL_GPL(xprt_disconnect_done); 622 623/** 624 * xprt_force_disconnect - force a transport to disconnect 625 * @xprt: transport to disconnect 626 * 627 */ 628void xprt_force_disconnect(struct rpc_xprt *xprt) 629{ 630 /* Don't race with the test_bit() in xprt_clear_locked() */ 631 spin_lock_bh(&xprt->transport_lock); 632 set_bit(XPRT_CLOSE_WAIT, &xprt->state); 633 /* Try to schedule an autoclose RPC call */ 634 if (test_and_set_bit(XPRT_LOCKED, &xprt->state) == 0) 635 queue_work(rpciod_workqueue, &xprt->task_cleanup); 636 xprt_wake_pending_tasks(xprt, -EAGAIN); 637 spin_unlock_bh(&xprt->transport_lock); 638} 639 640/** 641 * xprt_conditional_disconnect - force a transport to disconnect 642 * @xprt: transport to disconnect 643 * @cookie: 'connection cookie' 644 * 645 * This attempts to break the connection if and only if 'cookie' matches 646 * the current transport 'connection cookie'. It ensures that we don't 647 * try to break the connection more than once when we need to retransmit 648 * a batch of RPC requests. 649 * 650 */ 651void xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie) 652{ 653 /* Don't race with the test_bit() in xprt_clear_locked() */ 654 spin_lock_bh(&xprt->transport_lock); 655 if (cookie != xprt->connect_cookie) 656 goto out; 657 if (test_bit(XPRT_CLOSING, &xprt->state) || !xprt_connected(xprt)) 658 goto out; 659 set_bit(XPRT_CLOSE_WAIT, &xprt->state); 660 /* Try to schedule an autoclose RPC call */ 661 if (test_and_set_bit(XPRT_LOCKED, &xprt->state) == 0) 662 queue_work(rpciod_workqueue, &xprt->task_cleanup); 663 xprt_wake_pending_tasks(xprt, -EAGAIN); 664out: 665 spin_unlock_bh(&xprt->transport_lock); 666} 667 668static void 669xprt_init_autodisconnect(unsigned long data) 670{ 671 struct rpc_xprt *xprt = (struct rpc_xprt *)data; 672 673 spin_lock(&xprt->transport_lock); 674 if (!list_empty(&xprt->recv) || xprt->shutdown) 675 goto out_abort; 676 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) 677 goto out_abort; 678 spin_unlock(&xprt->transport_lock); 679 set_bit(XPRT_CONNECTION_CLOSE, &xprt->state); 680 queue_work(rpciod_workqueue, &xprt->task_cleanup); 681 return; 682out_abort: 683 spin_unlock(&xprt->transport_lock); 684} 685 686/** 687 * xprt_connect - schedule a transport connect operation 688 * @task: RPC task that is requesting the connect 689 * 690 */ 691void xprt_connect(struct rpc_task *task) 692{ 693 struct rpc_xprt *xprt = task->tk_xprt; 694 695 dprintk("RPC: %5u xprt_connect xprt %p %s connected\n", task->tk_pid, 696 xprt, (xprt_connected(xprt) ? "is" : "is not")); 697 698 if (!xprt_bound(xprt)) { 699 task->tk_status = -EAGAIN; 700 return; 701 } 702 if (!xprt_lock_write(xprt, task)) 703 return; 704 705 if (test_and_clear_bit(XPRT_CLOSE_WAIT, &xprt->state)) 706 xprt->ops->close(xprt); 707 708 if (xprt_connected(xprt)) 709 xprt_release_write(xprt, task); 710 else { 711 if (task->tk_rqstp) 712 task->tk_rqstp->rq_bytes_sent = 0; 713 714 task->tk_timeout = task->tk_rqstp->rq_timeout; 715 rpc_sleep_on(&xprt->pending, task, xprt_connect_status); 716 717 if (test_bit(XPRT_CLOSING, &xprt->state)) 718 return; 719 if (xprt_test_and_set_connecting(xprt)) 720 return; 721 xprt->stat.connect_start = jiffies; 722 xprt->ops->connect(task); 723 } 724} 725 726static void xprt_connect_status(struct rpc_task *task) 727{ 728 struct rpc_xprt *xprt = task->tk_xprt; 729 730 if (task->tk_status == 0) { 731 xprt->stat.connect_count++; 732 xprt->stat.connect_time += (long)jiffies - xprt->stat.connect_start; 733 dprintk("RPC: %5u xprt_connect_status: connection established\n", 734 task->tk_pid); 735 return; 736 } 737 738 switch (task->tk_status) { 739 case -EAGAIN: 740 dprintk("RPC: %5u xprt_connect_status: retrying\n", task->tk_pid); 741 break; 742 case -ETIMEDOUT: 743 dprintk("RPC: %5u xprt_connect_status: connect attempt timed " 744 "out\n", task->tk_pid); 745 break; 746 default: 747 dprintk("RPC: %5u xprt_connect_status: error %d connecting to " 748 "server %s\n", task->tk_pid, -task->tk_status, 749 task->tk_client->cl_server); 750 xprt_release_write(xprt, task); 751 task->tk_status = -EIO; 752 } 753} 754 755/** 756 * xprt_lookup_rqst - find an RPC request corresponding to an XID 757 * @xprt: transport on which the original request was transmitted 758 * @xid: RPC XID of incoming reply 759 * 760 */ 761struct rpc_rqst *xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid) 762{ 763 struct rpc_rqst *entry; 764 765 list_for_each_entry(entry, &xprt->recv, rq_list) 766 if (entry->rq_xid == xid) 767 return entry; 768 769 dprintk("RPC: xprt_lookup_rqst did not find xid %08x\n", 770 ntohl(xid)); 771 xprt->stat.bad_xids++; 772 return NULL; 773} 774EXPORT_SYMBOL_GPL(xprt_lookup_rqst); 775 776static void xprt_update_rtt(struct rpc_task *task) 777{ 778 struct rpc_rqst *req = task->tk_rqstp; 779 struct rpc_rtt *rtt = task->tk_client->cl_rtt; 780 unsigned timer = task->tk_msg.rpc_proc->p_timer; 781 long m = usecs_to_jiffies(ktime_to_us(req->rq_rtt)); 782 783 if (timer) { 784 if (req->rq_ntrans == 1) 785 rpc_update_rtt(rtt, timer, m); 786 rpc_set_timeo(rtt, timer, req->rq_ntrans - 1); 787 } 788} 789 790/** 791 * xprt_complete_rqst - called when reply processing is complete 792 * @task: RPC request that recently completed 793 * @copied: actual number of bytes received from the transport 794 * 795 * Caller holds transport lock. 796 */ 797void xprt_complete_rqst(struct rpc_task *task, int copied) 798{ 799 struct rpc_rqst *req = task->tk_rqstp; 800 struct rpc_xprt *xprt = req->rq_xprt; 801 802 dprintk("RPC: %5u xid %08x complete (%d bytes received)\n", 803 task->tk_pid, ntohl(req->rq_xid), copied); 804 805 xprt->stat.recvs++; 806 req->rq_rtt = ktime_sub(ktime_get(), req->rq_xtime); 807 if (xprt->ops->timer != NULL) 808 xprt_update_rtt(task); 809 810 list_del_init(&req->rq_list); 811 req->rq_private_buf.len = copied; 812 /* Ensure all writes are done before we update */ 813 /* req->rq_reply_bytes_recvd */ 814 smp_wmb(); 815 req->rq_reply_bytes_recvd = copied; 816 rpc_wake_up_queued_task(&xprt->pending, task); 817} 818EXPORT_SYMBOL_GPL(xprt_complete_rqst); 819 820static void xprt_timer(struct rpc_task *task) 821{ 822 struct rpc_rqst *req = task->tk_rqstp; 823 struct rpc_xprt *xprt = req->rq_xprt; 824 825 if (task->tk_status != -ETIMEDOUT) 826 return; 827 dprintk("RPC: %5u xprt_timer\n", task->tk_pid); 828 829 spin_lock_bh(&xprt->transport_lock); 830 if (!req->rq_reply_bytes_recvd) { 831 if (xprt->ops->timer) 832 xprt->ops->timer(task); 833 } else 834 task->tk_status = 0; 835 spin_unlock_bh(&xprt->transport_lock); 836} 837 838static inline int xprt_has_timer(struct rpc_xprt *xprt) 839{ 840 return xprt->idle_timeout != 0; 841} 842 843/** 844 * xprt_prepare_transmit - reserve the transport before sending a request 845 * @task: RPC task about to send a request 846 * 847 */ 848int xprt_prepare_transmit(struct rpc_task *task) 849{ 850 struct rpc_rqst *req = task->tk_rqstp; 851 struct rpc_xprt *xprt = req->rq_xprt; 852 int err = 0; 853 854 dprintk("RPC: %5u xprt_prepare_transmit\n", task->tk_pid); 855 856 spin_lock_bh(&xprt->transport_lock); 857 if (req->rq_reply_bytes_recvd && !req->rq_bytes_sent) { 858 err = req->rq_reply_bytes_recvd; 859 goto out_unlock; 860 } 861 if (!xprt->ops->reserve_xprt(xprt, task)) 862 err = -EAGAIN; 863out_unlock: 864 spin_unlock_bh(&xprt->transport_lock); 865 return err; 866} 867 868void xprt_end_transmit(struct rpc_task *task) 869{ 870 xprt_release_write(task->tk_rqstp->rq_xprt, task); 871} 872 873/** 874 * xprt_transmit - send an RPC request on a transport 875 * @task: controlling RPC task 876 * 877 * We have to copy the iovec because sendmsg fiddles with its contents. 878 */ 879void xprt_transmit(struct rpc_task *task) 880{ 881 struct rpc_rqst *req = task->tk_rqstp; 882 struct rpc_xprt *xprt = req->rq_xprt; 883 int status; 884 885 dprintk("RPC: %5u xprt_transmit(%u)\n", task->tk_pid, req->rq_slen); 886 887 if (!req->rq_reply_bytes_recvd) { 888 if (list_empty(&req->rq_list) && rpc_reply_expected(task)) { 889 /* 890 * Add to the list only if we're expecting a reply 891 */ 892 spin_lock_bh(&xprt->transport_lock); 893 /* Update the softirq receive buffer */ 894 memcpy(&req->rq_private_buf, &req->rq_rcv_buf, 895 sizeof(req->rq_private_buf)); 896 /* Add request to the receive list */ 897 list_add_tail(&req->rq_list, &xprt->recv); 898 spin_unlock_bh(&xprt->transport_lock); 899 xprt_reset_majortimeo(req); 900 /* Turn off autodisconnect */ 901 del_singleshot_timer_sync(&xprt->timer); 902 } 903 } else if (!req->rq_bytes_sent) 904 return; 905 906 req->rq_connect_cookie = xprt->connect_cookie; 907 req->rq_xtime = ktime_get(); 908 status = xprt->ops->send_request(task); 909 if (status != 0) { 910 task->tk_status = status; 911 return; 912 } 913 914 dprintk("RPC: %5u xmit complete\n", task->tk_pid); 915 task->tk_flags |= RPC_TASK_SENT; 916 spin_lock_bh(&xprt->transport_lock); 917 918 xprt->ops->set_retrans_timeout(task); 919 920 xprt->stat.sends++; 921 xprt->stat.req_u += xprt->stat.sends - xprt->stat.recvs; 922 xprt->stat.bklog_u += xprt->backlog.qlen; 923 924 /* Don't race with disconnect */ 925 if (!xprt_connected(xprt)) 926 task->tk_status = -ENOTCONN; 927 else if (!req->rq_reply_bytes_recvd && rpc_reply_expected(task)) { 928 /* 929 * Sleep on the pending queue since 930 * we're expecting a reply. 931 */ 932 rpc_sleep_on(&xprt->pending, task, xprt_timer); 933 } 934 spin_unlock_bh(&xprt->transport_lock); 935} 936 937static void xprt_alloc_slot(struct rpc_task *task) 938{ 939 struct rpc_xprt *xprt = task->tk_xprt; 940 941 task->tk_status = 0; 942 if (!list_empty(&xprt->free)) { 943 struct rpc_rqst *req = list_entry(xprt->free.next, struct rpc_rqst, rq_list); 944 list_del_init(&req->rq_list); 945 task->tk_rqstp = req; 946 xprt_request_init(task, xprt); 947 return; 948 } 949 dprintk("RPC: waiting for request slot\n"); 950 task->tk_status = -EAGAIN; 951 rpc_sleep_on(&xprt->backlog, task, NULL); 952} 953 954static void xprt_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *req) 955{ 956 memset(req, 0, sizeof(*req)); /* mark unused */ 957 958 spin_lock(&xprt->reserve_lock); 959 list_add(&req->rq_list, &xprt->free); 960 rpc_wake_up_next(&xprt->backlog); 961 spin_unlock(&xprt->reserve_lock); 962} 963 964struct rpc_xprt *xprt_alloc(struct net *net, int size, int max_req) 965{ 966 struct rpc_xprt *xprt; 967 968 xprt = kzalloc(size, GFP_KERNEL); 969 if (xprt == NULL) 970 goto out; 971 atomic_set(&xprt->count, 1); 972 973 xprt->max_reqs = max_req; 974 xprt->slot = kcalloc(max_req, sizeof(struct rpc_rqst), GFP_KERNEL); 975 if (xprt->slot == NULL) 976 goto out_free; 977 978 xprt->xprt_net = get_net(net); 979 return xprt; 980 981out_free: 982 kfree(xprt); 983out: 984 return NULL; 985} 986EXPORT_SYMBOL_GPL(xprt_alloc); 987 988void xprt_free(struct rpc_xprt *xprt) 989{ 990 put_net(xprt->xprt_net); 991 kfree(xprt->slot); 992 kfree(xprt); 993} 994EXPORT_SYMBOL_GPL(xprt_free); 995 996/** 997 * xprt_reserve - allocate an RPC request slot 998 * @task: RPC task requesting a slot allocation 999 * 1000 * If no more slots are available, place the task on the transport's 1001 * backlog queue. 1002 */ 1003void xprt_reserve(struct rpc_task *task) 1004{ 1005 struct rpc_xprt *xprt = task->tk_xprt; 1006 1007 task->tk_status = 0; 1008 if (task->tk_rqstp != NULL) 1009 return; 1010 1011 /* Note: grabbing the xprt_lock_write() here is not strictly needed, 1012 * but ensures that we throttle new slot allocation if the transport 1013 * is congested (e.g. if reconnecting or if we're out of socket 1014 * write buffer space). 1015 */ 1016 task->tk_timeout = 0; 1017 task->tk_status = -EAGAIN; 1018 if (!xprt_lock_write(xprt, task)) 1019 return; 1020 1021 task->tk_status = -EIO; 1022 spin_lock(&xprt->reserve_lock); 1023 xprt_alloc_slot(task); 1024 spin_unlock(&xprt->reserve_lock); 1025 xprt_release_write(xprt, task); 1026} 1027 1028static inline __be32 xprt_alloc_xid(struct rpc_xprt *xprt) 1029{ 1030 return (__force __be32)xprt->xid++; 1031} 1032 1033static inline void xprt_init_xid(struct rpc_xprt *xprt) 1034{ 1035 xprt->xid = net_random(); 1036} 1037 1038static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt) 1039{ 1040 struct rpc_rqst *req = task->tk_rqstp; 1041 1042 req->rq_timeout = task->tk_client->cl_timeout->to_initval; 1043 req->rq_task = task; 1044 req->rq_xprt = xprt; 1045 req->rq_buffer = NULL; 1046 req->rq_xid = xprt_alloc_xid(xprt); 1047 req->rq_release_snd_buf = NULL; 1048 xprt_reset_majortimeo(req); 1049 dprintk("RPC: %5u reserved req %p xid %08x\n", task->tk_pid, 1050 req, ntohl(req->rq_xid)); 1051} 1052 1053/** 1054 * xprt_release - release an RPC request slot 1055 * @task: task which is finished with the slot 1056 * 1057 */ 1058void xprt_release(struct rpc_task *task) 1059{ 1060 struct rpc_xprt *xprt; 1061 struct rpc_rqst *req; 1062 1063 if (!(req = task->tk_rqstp)) 1064 return; 1065 1066 xprt = req->rq_xprt; 1067 rpc_count_iostats(task); 1068 spin_lock_bh(&xprt->transport_lock); 1069 xprt->ops->release_xprt(xprt, task); 1070 if (xprt->ops->release_request) 1071 xprt->ops->release_request(task); 1072 if (!list_empty(&req->rq_list)) 1073 list_del(&req->rq_list); 1074 xprt->last_used = jiffies; 1075 if (list_empty(&xprt->recv) && xprt_has_timer(xprt)) 1076 mod_timer(&xprt->timer, 1077 xprt->last_used + xprt->idle_timeout); 1078 spin_unlock_bh(&xprt->transport_lock); 1079 if (req->rq_buffer) 1080 xprt->ops->buf_free(req->rq_buffer); 1081 if (req->rq_cred != NULL) 1082 put_rpccred(req->rq_cred); 1083 task->tk_rqstp = NULL; 1084 if (req->rq_release_snd_buf) 1085 req->rq_release_snd_buf(req); 1086 1087 dprintk("RPC: %5u release request %p\n", task->tk_pid, req); 1088 if (likely(!bc_prealloc(req))) 1089 xprt_free_slot(xprt, req); 1090 else 1091 xprt_free_bc_request(req); 1092} 1093 1094/** 1095 * xprt_create_transport - create an RPC transport 1096 * @args: rpc transport creation arguments 1097 * 1098 */ 1099struct rpc_xprt *xprt_create_transport(struct xprt_create *args) 1100{ 1101 struct rpc_xprt *xprt; 1102 struct rpc_rqst *req; 1103 struct xprt_class *t; 1104 1105 spin_lock(&xprt_list_lock); 1106 list_for_each_entry(t, &xprt_list, list) { 1107 if (t->ident == args->ident) { 1108 spin_unlock(&xprt_list_lock); 1109 goto found; 1110 } 1111 } 1112 spin_unlock(&xprt_list_lock); 1113 printk(KERN_ERR "RPC: transport (%d) not supported\n", args->ident); 1114 return ERR_PTR(-EIO); 1115 1116found: 1117 xprt = t->setup(args); 1118 if (IS_ERR(xprt)) { 1119 dprintk("RPC: xprt_create_transport: failed, %ld\n", 1120 -PTR_ERR(xprt)); 1121 return xprt; 1122 } 1123 if (test_and_set_bit(XPRT_INITIALIZED, &xprt->state)) 1124 /* ->setup returned a pre-initialized xprt: */ 1125 return xprt; 1126 1127 spin_lock_init(&xprt->transport_lock); 1128 spin_lock_init(&xprt->reserve_lock); 1129 1130 INIT_LIST_HEAD(&xprt->free); 1131 INIT_LIST_HEAD(&xprt->recv); 1132#if defined(CONFIG_SUNRPC_BACKCHANNEL) 1133 spin_lock_init(&xprt->bc_pa_lock); 1134 INIT_LIST_HEAD(&xprt->bc_pa_list); 1135#endif /* CONFIG_SUNRPC_BACKCHANNEL */ 1136 1137 INIT_WORK(&xprt->task_cleanup, xprt_autoclose); 1138 if (xprt_has_timer(xprt)) 1139 setup_timer(&xprt->timer, xprt_init_autodisconnect, 1140 (unsigned long)xprt); 1141 else 1142 init_timer(&xprt->timer); 1143 xprt->last_used = jiffies; 1144 xprt->cwnd = RPC_INITCWND; 1145 xprt->bind_index = 0; 1146 1147 rpc_init_wait_queue(&xprt->binding, "xprt_binding"); 1148 rpc_init_wait_queue(&xprt->pending, "xprt_pending"); 1149 rpc_init_wait_queue(&xprt->sending, "xprt_sending"); 1150 rpc_init_wait_queue(&xprt->resend, "xprt_resend"); 1151 rpc_init_priority_wait_queue(&xprt->backlog, "xprt_backlog"); 1152 1153 /* initialize free list */ 1154 for (req = &xprt->slot[xprt->max_reqs-1]; req >= &xprt->slot[0]; req--) 1155 list_add(&req->rq_list, &xprt->free); 1156 1157 xprt_init_xid(xprt); 1158 1159 dprintk("RPC: created transport %p with %u slots\n", xprt, 1160 xprt->max_reqs); 1161 return xprt; 1162} 1163 1164/** 1165 * xprt_destroy - destroy an RPC transport, killing off all requests. 1166 * @xprt: transport to destroy 1167 * 1168 */ 1169static void xprt_destroy(struct rpc_xprt *xprt) 1170{ 1171 dprintk("RPC: destroying transport %p\n", xprt); 1172 xprt->shutdown = 1; 1173 del_timer_sync(&xprt->timer); 1174 1175 rpc_destroy_wait_queue(&xprt->binding); 1176 rpc_destroy_wait_queue(&xprt->pending); 1177 rpc_destroy_wait_queue(&xprt->sending); 1178 rpc_destroy_wait_queue(&xprt->resend); 1179 rpc_destroy_wait_queue(&xprt->backlog); 1180 cancel_work_sync(&xprt->task_cleanup); 1181 /* 1182 * Tear down transport state and free the rpc_xprt 1183 */ 1184 xprt->ops->destroy(xprt); 1185} 1186 1187/** 1188 * xprt_put - release a reference to an RPC transport. 1189 * @xprt: pointer to the transport 1190 * 1191 */ 1192void xprt_put(struct rpc_xprt *xprt) 1193{ 1194 if (atomic_dec_and_test(&xprt->count)) 1195 xprt_destroy(xprt); 1196} 1197 1198/** 1199 * xprt_get - return a reference to an RPC transport. 1200 * @xprt: pointer to the transport 1201 * 1202 */ 1203struct rpc_xprt *xprt_get(struct rpc_xprt *xprt) 1204{ 1205 if (atomic_inc_not_zero(&xprt->count)) 1206 return xprt; 1207 return NULL; 1208} 1209