xprt.c revision 343952fa5aac888934ffc203abed26a823400eb6
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 47#include <linux/sunrpc/clnt.h> 48#include <linux/sunrpc/metrics.h> 49 50#include "sunrpc.h" 51 52/* 53 * Local variables 54 */ 55 56#ifdef RPC_DEBUG 57# define RPCDBG_FACILITY RPCDBG_XPRT 58#endif 59 60/* 61 * Local functions 62 */ 63static void xprt_request_init(struct rpc_task *, struct rpc_xprt *); 64static inline void do_xprt_reserve(struct rpc_task *); 65static void xprt_connect_status(struct rpc_task *task); 66static int __xprt_get_cong(struct rpc_xprt *, struct rpc_task *); 67 68static DEFINE_SPINLOCK(xprt_list_lock); 69static LIST_HEAD(xprt_list); 70 71/* 72 * The transport code maintains an estimate on the maximum number of out- 73 * standing RPC requests, using a smoothed version of the congestion 74 * avoidance implemented in 44BSD. This is basically the Van Jacobson 75 * congestion algorithm: If a retransmit occurs, the congestion window is 76 * halved; otherwise, it is incremented by 1/cwnd when 77 * 78 * - a reply is received and 79 * - a full number of requests are outstanding and 80 * - the congestion window hasn't been updated recently. 81 */ 82#define RPC_CWNDSHIFT (8U) 83#define RPC_CWNDSCALE (1U << RPC_CWNDSHIFT) 84#define RPC_INITCWND RPC_CWNDSCALE 85#define RPC_MAXCWND(xprt) ((xprt)->max_reqs << RPC_CWNDSHIFT) 86 87#define RPCXPRT_CONGESTED(xprt) ((xprt)->cong >= (xprt)->cwnd) 88 89/** 90 * xprt_register_transport - register a transport implementation 91 * @transport: transport to register 92 * 93 * If a transport implementation is loaded as a kernel module, it can 94 * call this interface to make itself known to the RPC client. 95 * 96 * Returns: 97 * 0: transport successfully registered 98 * -EEXIST: transport already registered 99 * -EINVAL: transport module being unloaded 100 */ 101int xprt_register_transport(struct xprt_class *transport) 102{ 103 struct xprt_class *t; 104 int result; 105 106 result = -EEXIST; 107 spin_lock(&xprt_list_lock); 108 list_for_each_entry(t, &xprt_list, list) { 109 /* don't register the same transport class twice */ 110 if (t->ident == transport->ident) 111 goto out; 112 } 113 114 list_add_tail(&transport->list, &xprt_list); 115 printk(KERN_INFO "RPC: Registered %s transport module.\n", 116 transport->name); 117 result = 0; 118 119out: 120 spin_unlock(&xprt_list_lock); 121 return result; 122} 123EXPORT_SYMBOL_GPL(xprt_register_transport); 124 125/** 126 * xprt_unregister_transport - unregister a transport implementation 127 * @transport: transport to unregister 128 * 129 * Returns: 130 * 0: transport successfully unregistered 131 * -ENOENT: transport never registered 132 */ 133int xprt_unregister_transport(struct xprt_class *transport) 134{ 135 struct xprt_class *t; 136 int result; 137 138 result = 0; 139 spin_lock(&xprt_list_lock); 140 list_for_each_entry(t, &xprt_list, list) { 141 if (t == transport) { 142 printk(KERN_INFO 143 "RPC: Unregistered %s transport module.\n", 144 transport->name); 145 list_del_init(&transport->list); 146 goto out; 147 } 148 } 149 result = -ENOENT; 150 151out: 152 spin_unlock(&xprt_list_lock); 153 return result; 154} 155EXPORT_SYMBOL_GPL(xprt_unregister_transport); 156 157/** 158 * xprt_load_transport - load a transport implementation 159 * @transport_name: transport to load 160 * 161 * Returns: 162 * 0: transport successfully loaded 163 * -ENOENT: transport module not available 164 */ 165int xprt_load_transport(const char *transport_name) 166{ 167 struct xprt_class *t; 168 char module_name[sizeof t->name + 5]; 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 strcpy(module_name, "xprt"); 181 strncat(module_name, transport_name, sizeof t->name); 182 result = request_module(module_name); 183out: 184 return result; 185} 186EXPORT_SYMBOL_GPL(xprt_load_transport); 187 188/** 189 * xprt_reserve_xprt - serialize write access to transports 190 * @task: task that is requesting access to the transport 191 * 192 * This prevents mixing the payload of separate requests, and prevents 193 * transport connects from colliding with writes. No congestion control 194 * is provided. 195 */ 196int xprt_reserve_xprt(struct rpc_task *task) 197{ 198 struct rpc_rqst *req = task->tk_rqstp; 199 struct rpc_xprt *xprt = req->rq_xprt; 200 201 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) { 202 if (task == xprt->snd_task) 203 return 1; 204 if (task == NULL) 205 return 0; 206 goto out_sleep; 207 } 208 xprt->snd_task = task; 209 if (req) { 210 req->rq_bytes_sent = 0; 211 req->rq_ntrans++; 212 } 213 return 1; 214 215out_sleep: 216 dprintk("RPC: %5u failed to lock transport %p\n", 217 task->tk_pid, xprt); 218 task->tk_timeout = 0; 219 task->tk_status = -EAGAIN; 220 if (req && req->rq_ntrans) 221 rpc_sleep_on(&xprt->resend, task, NULL); 222 else 223 rpc_sleep_on(&xprt->sending, task, NULL); 224 return 0; 225} 226EXPORT_SYMBOL_GPL(xprt_reserve_xprt); 227 228static void xprt_clear_locked(struct rpc_xprt *xprt) 229{ 230 xprt->snd_task = NULL; 231 if (!test_bit(XPRT_CLOSE_WAIT, &xprt->state) || xprt->shutdown) { 232 smp_mb__before_clear_bit(); 233 clear_bit(XPRT_LOCKED, &xprt->state); 234 smp_mb__after_clear_bit(); 235 } else 236 queue_work(rpciod_workqueue, &xprt->task_cleanup); 237} 238 239/* 240 * xprt_reserve_xprt_cong - serialize write access to transports 241 * @task: task that is requesting access to the transport 242 * 243 * Same as xprt_reserve_xprt, but Van Jacobson congestion control is 244 * integrated into the decision of whether a request is allowed to be 245 * woken up and given access to the transport. 246 */ 247int xprt_reserve_xprt_cong(struct rpc_task *task) 248{ 249 struct rpc_xprt *xprt = task->tk_xprt; 250 struct rpc_rqst *req = task->tk_rqstp; 251 252 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) { 253 if (task == xprt->snd_task) 254 return 1; 255 goto out_sleep; 256 } 257 if (__xprt_get_cong(xprt, task)) { 258 xprt->snd_task = task; 259 if (req) { 260 req->rq_bytes_sent = 0; 261 req->rq_ntrans++; 262 } 263 return 1; 264 } 265 xprt_clear_locked(xprt); 266out_sleep: 267 dprintk("RPC: %5u failed to lock transport %p\n", task->tk_pid, xprt); 268 task->tk_timeout = 0; 269 task->tk_status = -EAGAIN; 270 if (req && req->rq_ntrans) 271 rpc_sleep_on(&xprt->resend, task, NULL); 272 else 273 rpc_sleep_on(&xprt->sending, task, NULL); 274 return 0; 275} 276EXPORT_SYMBOL_GPL(xprt_reserve_xprt_cong); 277 278static inline int xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task) 279{ 280 int retval; 281 282 spin_lock_bh(&xprt->transport_lock); 283 retval = xprt->ops->reserve_xprt(task); 284 spin_unlock_bh(&xprt->transport_lock); 285 return retval; 286} 287 288static void __xprt_lock_write_next(struct rpc_xprt *xprt) 289{ 290 struct rpc_task *task; 291 struct rpc_rqst *req; 292 293 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) 294 return; 295 296 task = rpc_wake_up_next(&xprt->resend); 297 if (!task) { 298 task = rpc_wake_up_next(&xprt->sending); 299 if (!task) 300 goto out_unlock; 301 } 302 303 req = task->tk_rqstp; 304 xprt->snd_task = task; 305 if (req) { 306 req->rq_bytes_sent = 0; 307 req->rq_ntrans++; 308 } 309 return; 310 311out_unlock: 312 xprt_clear_locked(xprt); 313} 314 315static void __xprt_lock_write_next_cong(struct rpc_xprt *xprt) 316{ 317 struct rpc_task *task; 318 319 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) 320 return; 321 if (RPCXPRT_CONGESTED(xprt)) 322 goto out_unlock; 323 task = rpc_wake_up_next(&xprt->resend); 324 if (!task) { 325 task = rpc_wake_up_next(&xprt->sending); 326 if (!task) 327 goto out_unlock; 328 } 329 if (__xprt_get_cong(xprt, task)) { 330 struct rpc_rqst *req = task->tk_rqstp; 331 xprt->snd_task = task; 332 if (req) { 333 req->rq_bytes_sent = 0; 334 req->rq_ntrans++; 335 } 336 return; 337 } 338out_unlock: 339 xprt_clear_locked(xprt); 340} 341 342/** 343 * xprt_release_xprt - allow other requests to use a transport 344 * @xprt: transport with other tasks potentially waiting 345 * @task: task that is releasing access to the transport 346 * 347 * Note that "task" can be NULL. No congestion control is provided. 348 */ 349void xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task) 350{ 351 if (xprt->snd_task == task) { 352 xprt_clear_locked(xprt); 353 __xprt_lock_write_next(xprt); 354 } 355} 356EXPORT_SYMBOL_GPL(xprt_release_xprt); 357 358/** 359 * xprt_release_xprt_cong - allow other requests to use a transport 360 * @xprt: transport with other tasks potentially waiting 361 * @task: task that is releasing access to the transport 362 * 363 * Note that "task" can be NULL. Another task is awoken to use the 364 * transport if the transport's congestion window allows it. 365 */ 366void xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task) 367{ 368 if (xprt->snd_task == task) { 369 xprt_clear_locked(xprt); 370 __xprt_lock_write_next_cong(xprt); 371 } 372} 373EXPORT_SYMBOL_GPL(xprt_release_xprt_cong); 374 375static inline void xprt_release_write(struct rpc_xprt *xprt, struct rpc_task *task) 376{ 377 spin_lock_bh(&xprt->transport_lock); 378 xprt->ops->release_xprt(xprt, task); 379 spin_unlock_bh(&xprt->transport_lock); 380} 381 382/* 383 * Van Jacobson congestion avoidance. Check if the congestion window 384 * overflowed. Put the task to sleep if this is the case. 385 */ 386static int 387__xprt_get_cong(struct rpc_xprt *xprt, struct rpc_task *task) 388{ 389 struct rpc_rqst *req = task->tk_rqstp; 390 391 if (req->rq_cong) 392 return 1; 393 dprintk("RPC: %5u xprt_cwnd_limited cong = %lu cwnd = %lu\n", 394 task->tk_pid, xprt->cong, xprt->cwnd); 395 if (RPCXPRT_CONGESTED(xprt)) 396 return 0; 397 req->rq_cong = 1; 398 xprt->cong += RPC_CWNDSCALE; 399 return 1; 400} 401 402/* 403 * Adjust the congestion window, and wake up the next task 404 * that has been sleeping due to congestion 405 */ 406static void 407__xprt_put_cong(struct rpc_xprt *xprt, struct rpc_rqst *req) 408{ 409 if (!req->rq_cong) 410 return; 411 req->rq_cong = 0; 412 xprt->cong -= RPC_CWNDSCALE; 413 __xprt_lock_write_next_cong(xprt); 414} 415 416/** 417 * xprt_release_rqst_cong - housekeeping when request is complete 418 * @task: RPC request that recently completed 419 * 420 * Useful for transports that require congestion control. 421 */ 422void xprt_release_rqst_cong(struct rpc_task *task) 423{ 424 __xprt_put_cong(task->tk_xprt, task->tk_rqstp); 425} 426EXPORT_SYMBOL_GPL(xprt_release_rqst_cong); 427 428/** 429 * xprt_adjust_cwnd - adjust transport congestion window 430 * @task: recently completed RPC request used to adjust window 431 * @result: result code of completed RPC request 432 * 433 * We use a time-smoothed congestion estimator to avoid heavy oscillation. 434 */ 435void xprt_adjust_cwnd(struct rpc_task *task, int result) 436{ 437 struct rpc_rqst *req = task->tk_rqstp; 438 struct rpc_xprt *xprt = task->tk_xprt; 439 unsigned long cwnd = xprt->cwnd; 440 441 if (result >= 0 && cwnd <= xprt->cong) { 442 /* The (cwnd >> 1) term makes sure 443 * the result gets rounded properly. */ 444 cwnd += (RPC_CWNDSCALE * RPC_CWNDSCALE + (cwnd >> 1)) / cwnd; 445 if (cwnd > RPC_MAXCWND(xprt)) 446 cwnd = RPC_MAXCWND(xprt); 447 __xprt_lock_write_next_cong(xprt); 448 } else if (result == -ETIMEDOUT) { 449 cwnd >>= 1; 450 if (cwnd < RPC_CWNDSCALE) 451 cwnd = RPC_CWNDSCALE; 452 } 453 dprintk("RPC: cong %ld, cwnd was %ld, now %ld\n", 454 xprt->cong, xprt->cwnd, cwnd); 455 xprt->cwnd = cwnd; 456 __xprt_put_cong(xprt, req); 457} 458EXPORT_SYMBOL_GPL(xprt_adjust_cwnd); 459 460/** 461 * xprt_wake_pending_tasks - wake all tasks on a transport's pending queue 462 * @xprt: transport with waiting tasks 463 * @status: result code to plant in each task before waking it 464 * 465 */ 466void xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status) 467{ 468 if (status < 0) 469 rpc_wake_up_status(&xprt->pending, status); 470 else 471 rpc_wake_up(&xprt->pending); 472} 473EXPORT_SYMBOL_GPL(xprt_wake_pending_tasks); 474 475/** 476 * xprt_wait_for_buffer_space - wait for transport output buffer to clear 477 * @task: task to be put to sleep 478 * @action: function pointer to be executed after wait 479 */ 480void xprt_wait_for_buffer_space(struct rpc_task *task, rpc_action action) 481{ 482 struct rpc_rqst *req = task->tk_rqstp; 483 struct rpc_xprt *xprt = req->rq_xprt; 484 485 task->tk_timeout = req->rq_timeout; 486 rpc_sleep_on(&xprt->pending, task, action); 487} 488EXPORT_SYMBOL_GPL(xprt_wait_for_buffer_space); 489 490/** 491 * xprt_write_space - wake the task waiting for transport output buffer space 492 * @xprt: transport with waiting tasks 493 * 494 * Can be called in a soft IRQ context, so xprt_write_space never sleeps. 495 */ 496void xprt_write_space(struct rpc_xprt *xprt) 497{ 498 if (unlikely(xprt->shutdown)) 499 return; 500 501 spin_lock_bh(&xprt->transport_lock); 502 if (xprt->snd_task) { 503 dprintk("RPC: write space: waking waiting task on " 504 "xprt %p\n", xprt); 505 rpc_wake_up_queued_task(&xprt->pending, xprt->snd_task); 506 } 507 spin_unlock_bh(&xprt->transport_lock); 508} 509EXPORT_SYMBOL_GPL(xprt_write_space); 510 511/** 512 * xprt_set_retrans_timeout_def - set a request's retransmit timeout 513 * @task: task whose timeout is to be set 514 * 515 * Set a request's retransmit timeout based on the transport's 516 * default timeout parameters. Used by transports that don't adjust 517 * the retransmit timeout based on round-trip time estimation. 518 */ 519void xprt_set_retrans_timeout_def(struct rpc_task *task) 520{ 521 task->tk_timeout = task->tk_rqstp->rq_timeout; 522} 523EXPORT_SYMBOL_GPL(xprt_set_retrans_timeout_def); 524 525/* 526 * xprt_set_retrans_timeout_rtt - set a request's retransmit timeout 527 * @task: task whose timeout is to be set 528 * 529 * Set a request's retransmit timeout using the RTT estimator. 530 */ 531void xprt_set_retrans_timeout_rtt(struct rpc_task *task) 532{ 533 int timer = task->tk_msg.rpc_proc->p_timer; 534 struct rpc_clnt *clnt = task->tk_client; 535 struct rpc_rtt *rtt = clnt->cl_rtt; 536 struct rpc_rqst *req = task->tk_rqstp; 537 unsigned long max_timeout = clnt->cl_timeout->to_maxval; 538 539 task->tk_timeout = rpc_calc_rto(rtt, timer); 540 task->tk_timeout <<= rpc_ntimeo(rtt, timer) + req->rq_retries; 541 if (task->tk_timeout > max_timeout || task->tk_timeout == 0) 542 task->tk_timeout = max_timeout; 543} 544EXPORT_SYMBOL_GPL(xprt_set_retrans_timeout_rtt); 545 546static void xprt_reset_majortimeo(struct rpc_rqst *req) 547{ 548 const struct rpc_timeout *to = req->rq_task->tk_client->cl_timeout; 549 550 req->rq_majortimeo = req->rq_timeout; 551 if (to->to_exponential) 552 req->rq_majortimeo <<= to->to_retries; 553 else 554 req->rq_majortimeo += to->to_increment * to->to_retries; 555 if (req->rq_majortimeo > to->to_maxval || req->rq_majortimeo == 0) 556 req->rq_majortimeo = to->to_maxval; 557 req->rq_majortimeo += jiffies; 558} 559 560/** 561 * xprt_adjust_timeout - adjust timeout values for next retransmit 562 * @req: RPC request containing parameters to use for the adjustment 563 * 564 */ 565int xprt_adjust_timeout(struct rpc_rqst *req) 566{ 567 struct rpc_xprt *xprt = req->rq_xprt; 568 const struct rpc_timeout *to = req->rq_task->tk_client->cl_timeout; 569 int status = 0; 570 571 if (time_before(jiffies, req->rq_majortimeo)) { 572 if (to->to_exponential) 573 req->rq_timeout <<= 1; 574 else 575 req->rq_timeout += to->to_increment; 576 if (to->to_maxval && req->rq_timeout >= to->to_maxval) 577 req->rq_timeout = to->to_maxval; 578 req->rq_retries++; 579 } else { 580 req->rq_timeout = to->to_initval; 581 req->rq_retries = 0; 582 xprt_reset_majortimeo(req); 583 /* Reset the RTT counters == "slow start" */ 584 spin_lock_bh(&xprt->transport_lock); 585 rpc_init_rtt(req->rq_task->tk_client->cl_rtt, to->to_initval); 586 spin_unlock_bh(&xprt->transport_lock); 587 status = -ETIMEDOUT; 588 } 589 590 if (req->rq_timeout == 0) { 591 printk(KERN_WARNING "xprt_adjust_timeout: rq_timeout = 0!\n"); 592 req->rq_timeout = 5 * HZ; 593 } 594 return status; 595} 596 597static void xprt_autoclose(struct work_struct *work) 598{ 599 struct rpc_xprt *xprt = 600 container_of(work, struct rpc_xprt, task_cleanup); 601 602 xprt->ops->close(xprt); 603 clear_bit(XPRT_CLOSE_WAIT, &xprt->state); 604 xprt_release_write(xprt, NULL); 605} 606 607/** 608 * xprt_disconnect_done - mark a transport as disconnected 609 * @xprt: transport to flag for disconnect 610 * 611 */ 612void xprt_disconnect_done(struct rpc_xprt *xprt) 613{ 614 dprintk("RPC: disconnected transport %p\n", xprt); 615 spin_lock_bh(&xprt->transport_lock); 616 xprt_clear_connected(xprt); 617 xprt_wake_pending_tasks(xprt, -EAGAIN); 618 spin_unlock_bh(&xprt->transport_lock); 619} 620EXPORT_SYMBOL_GPL(xprt_disconnect_done); 621 622/** 623 * xprt_force_disconnect - force a transport to disconnect 624 * @xprt: transport to disconnect 625 * 626 */ 627void xprt_force_disconnect(struct rpc_xprt *xprt) 628{ 629 /* Don't race with the test_bit() in xprt_clear_locked() */ 630 spin_lock_bh(&xprt->transport_lock); 631 set_bit(XPRT_CLOSE_WAIT, &xprt->state); 632 /* Try to schedule an autoclose RPC call */ 633 if (test_and_set_bit(XPRT_LOCKED, &xprt->state) == 0) 634 queue_work(rpciod_workqueue, &xprt->task_cleanup); 635 xprt_wake_pending_tasks(xprt, -EAGAIN); 636 spin_unlock_bh(&xprt->transport_lock); 637} 638 639/** 640 * xprt_conditional_disconnect - force a transport to disconnect 641 * @xprt: transport to disconnect 642 * @cookie: 'connection cookie' 643 * 644 * This attempts to break the connection if and only if 'cookie' matches 645 * the current transport 'connection cookie'. It ensures that we don't 646 * try to break the connection more than once when we need to retransmit 647 * a batch of RPC requests. 648 * 649 */ 650void xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie) 651{ 652 /* Don't race with the test_bit() in xprt_clear_locked() */ 653 spin_lock_bh(&xprt->transport_lock); 654 if (cookie != xprt->connect_cookie) 655 goto out; 656 if (test_bit(XPRT_CLOSING, &xprt->state) || !xprt_connected(xprt)) 657 goto out; 658 set_bit(XPRT_CLOSE_WAIT, &xprt->state); 659 /* Try to schedule an autoclose RPC call */ 660 if (test_and_set_bit(XPRT_LOCKED, &xprt->state) == 0) 661 queue_work(rpciod_workqueue, &xprt->task_cleanup); 662 xprt_wake_pending_tasks(xprt, -EAGAIN); 663out: 664 spin_unlock_bh(&xprt->transport_lock); 665} 666 667static void 668xprt_init_autodisconnect(unsigned long data) 669{ 670 struct rpc_xprt *xprt = (struct rpc_xprt *)data; 671 672 spin_lock(&xprt->transport_lock); 673 if (!list_empty(&xprt->recv) || xprt->shutdown) 674 goto out_abort; 675 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) 676 goto out_abort; 677 spin_unlock(&xprt->transport_lock); 678 set_bit(XPRT_CONNECTION_CLOSE, &xprt->state); 679 queue_work(rpciod_workqueue, &xprt->task_cleanup); 680 return; 681out_abort: 682 spin_unlock(&xprt->transport_lock); 683} 684 685/** 686 * xprt_connect - schedule a transport connect operation 687 * @task: RPC task that is requesting the connect 688 * 689 */ 690void xprt_connect(struct rpc_task *task) 691{ 692 struct rpc_xprt *xprt = task->tk_xprt; 693 694 dprintk("RPC: %5u xprt_connect xprt %p %s connected\n", task->tk_pid, 695 xprt, (xprt_connected(xprt) ? "is" : "is not")); 696 697 if (!xprt_bound(xprt)) { 698 task->tk_status = -EAGAIN; 699 return; 700 } 701 if (!xprt_lock_write(xprt, task)) 702 return; 703 if (xprt_connected(xprt)) 704 xprt_release_write(xprt, task); 705 else { 706 if (task->tk_rqstp) 707 task->tk_rqstp->rq_bytes_sent = 0; 708 709 task->tk_timeout = xprt->connect_timeout; 710 rpc_sleep_on(&xprt->pending, task, xprt_connect_status); 711 xprt->stat.connect_start = jiffies; 712 xprt->ops->connect(task); 713 } 714 return; 715} 716 717static void xprt_connect_status(struct rpc_task *task) 718{ 719 struct rpc_xprt *xprt = task->tk_xprt; 720 721 if (task->tk_status == 0) { 722 xprt->stat.connect_count++; 723 xprt->stat.connect_time += (long)jiffies - xprt->stat.connect_start; 724 dprintk("RPC: %5u xprt_connect_status: connection established\n", 725 task->tk_pid); 726 return; 727 } 728 729 switch (task->tk_status) { 730 case -EAGAIN: 731 dprintk("RPC: %5u xprt_connect_status: retrying\n", task->tk_pid); 732 break; 733 case -ETIMEDOUT: 734 dprintk("RPC: %5u xprt_connect_status: connect attempt timed " 735 "out\n", task->tk_pid); 736 break; 737 default: 738 dprintk("RPC: %5u xprt_connect_status: error %d connecting to " 739 "server %s\n", task->tk_pid, -task->tk_status, 740 task->tk_client->cl_server); 741 xprt_release_write(xprt, task); 742 task->tk_status = -EIO; 743 } 744} 745 746/** 747 * xprt_lookup_rqst - find an RPC request corresponding to an XID 748 * @xprt: transport on which the original request was transmitted 749 * @xid: RPC XID of incoming reply 750 * 751 */ 752struct rpc_rqst *xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid) 753{ 754 struct list_head *pos; 755 756 list_for_each(pos, &xprt->recv) { 757 struct rpc_rqst *entry = list_entry(pos, struct rpc_rqst, rq_list); 758 if (entry->rq_xid == xid) 759 return entry; 760 } 761 762 dprintk("RPC: xprt_lookup_rqst did not find xid %08x\n", 763 ntohl(xid)); 764 xprt->stat.bad_xids++; 765 return NULL; 766} 767EXPORT_SYMBOL_GPL(xprt_lookup_rqst); 768 769/** 770 * xprt_update_rtt - update an RPC client's RTT state after receiving a reply 771 * @task: RPC request that recently completed 772 * 773 */ 774void xprt_update_rtt(struct rpc_task *task) 775{ 776 struct rpc_rqst *req = task->tk_rqstp; 777 struct rpc_rtt *rtt = task->tk_client->cl_rtt; 778 unsigned timer = task->tk_msg.rpc_proc->p_timer; 779 780 if (timer) { 781 if (req->rq_ntrans == 1) 782 rpc_update_rtt(rtt, timer, 783 (long)jiffies - req->rq_xtime); 784 rpc_set_timeo(rtt, timer, req->rq_ntrans - 1); 785 } 786} 787EXPORT_SYMBOL_GPL(xprt_update_rtt); 788 789/** 790 * xprt_complete_rqst - called when reply processing is complete 791 * @task: RPC request that recently completed 792 * @copied: actual number of bytes received from the transport 793 * 794 * Caller holds transport lock. 795 */ 796void xprt_complete_rqst(struct rpc_task *task, int copied) 797{ 798 struct rpc_rqst *req = task->tk_rqstp; 799 struct rpc_xprt *xprt = req->rq_xprt; 800 801 dprintk("RPC: %5u xid %08x complete (%d bytes received)\n", 802 task->tk_pid, ntohl(req->rq_xid), copied); 803 804 xprt->stat.recvs++; 805 task->tk_rtt = (long)jiffies - req->rq_xtime; 806 807 list_del_init(&req->rq_list); 808 req->rq_private_buf.len = copied; 809 /* Ensure all writes are done before we update req->rq_received */ 810 smp_wmb(); 811 req->rq_received = copied; 812 rpc_wake_up_queued_task(&xprt->pending, task); 813} 814EXPORT_SYMBOL_GPL(xprt_complete_rqst); 815 816static void xprt_timer(struct rpc_task *task) 817{ 818 struct rpc_rqst *req = task->tk_rqstp; 819 struct rpc_xprt *xprt = req->rq_xprt; 820 821 if (task->tk_status != -ETIMEDOUT) 822 return; 823 dprintk("RPC: %5u xprt_timer\n", task->tk_pid); 824 825 spin_lock_bh(&xprt->transport_lock); 826 if (!req->rq_received) { 827 if (xprt->ops->timer) 828 xprt->ops->timer(task); 829 } else 830 task->tk_status = 0; 831 spin_unlock_bh(&xprt->transport_lock); 832} 833 834/** 835 * xprt_prepare_transmit - reserve the transport before sending a request 836 * @task: RPC task about to send a request 837 * 838 */ 839int xprt_prepare_transmit(struct rpc_task *task) 840{ 841 struct rpc_rqst *req = task->tk_rqstp; 842 struct rpc_xprt *xprt = req->rq_xprt; 843 int err = 0; 844 845 dprintk("RPC: %5u xprt_prepare_transmit\n", task->tk_pid); 846 847 spin_lock_bh(&xprt->transport_lock); 848 if (req->rq_received && !req->rq_bytes_sent) { 849 err = req->rq_received; 850 goto out_unlock; 851 } 852 if (!xprt->ops->reserve_xprt(task)) 853 err = -EAGAIN; 854out_unlock: 855 spin_unlock_bh(&xprt->transport_lock); 856 return err; 857} 858 859void xprt_end_transmit(struct rpc_task *task) 860{ 861 xprt_release_write(task->tk_rqstp->rq_xprt, task); 862} 863 864/** 865 * xprt_transmit - send an RPC request on a transport 866 * @task: controlling RPC task 867 * 868 * We have to copy the iovec because sendmsg fiddles with its contents. 869 */ 870void xprt_transmit(struct rpc_task *task) 871{ 872 struct rpc_rqst *req = task->tk_rqstp; 873 struct rpc_xprt *xprt = req->rq_xprt; 874 int status; 875 876 dprintk("RPC: %5u xprt_transmit(%u)\n", task->tk_pid, req->rq_slen); 877 878 if (!req->rq_received) { 879 if (list_empty(&req->rq_list) && rpc_reply_expected(task)) { 880 /* 881 * Add to the list only if we're expecting a reply 882 */ 883 spin_lock_bh(&xprt->transport_lock); 884 /* Update the softirq receive buffer */ 885 memcpy(&req->rq_private_buf, &req->rq_rcv_buf, 886 sizeof(req->rq_private_buf)); 887 /* Add request to the receive list */ 888 list_add_tail(&req->rq_list, &xprt->recv); 889 spin_unlock_bh(&xprt->transport_lock); 890 xprt_reset_majortimeo(req); 891 /* Turn off autodisconnect */ 892 del_singleshot_timer_sync(&xprt->timer); 893 } 894 } else if (!req->rq_bytes_sent) 895 return; 896 897 req->rq_connect_cookie = xprt->connect_cookie; 898 req->rq_xtime = jiffies; 899 status = xprt->ops->send_request(task); 900 if (status != 0) { 901 task->tk_status = status; 902 return; 903 } 904 905 dprintk("RPC: %5u xmit complete\n", task->tk_pid); 906 spin_lock_bh(&xprt->transport_lock); 907 908 xprt->ops->set_retrans_timeout(task); 909 910 xprt->stat.sends++; 911 xprt->stat.req_u += xprt->stat.sends - xprt->stat.recvs; 912 xprt->stat.bklog_u += xprt->backlog.qlen; 913 914 /* Don't race with disconnect */ 915 if (!xprt_connected(xprt)) 916 task->tk_status = -ENOTCONN; 917 else if (!req->rq_received && rpc_reply_expected(task)) { 918 /* 919 * Sleep on the pending queue since 920 * we're expecting a reply. 921 */ 922 rpc_sleep_on(&xprt->pending, task, xprt_timer); 923 } 924 spin_unlock_bh(&xprt->transport_lock); 925} 926 927static inline void do_xprt_reserve(struct rpc_task *task) 928{ 929 struct rpc_xprt *xprt = task->tk_xprt; 930 931 task->tk_status = 0; 932 if (task->tk_rqstp) 933 return; 934 if (!list_empty(&xprt->free)) { 935 struct rpc_rqst *req = list_entry(xprt->free.next, struct rpc_rqst, rq_list); 936 list_del_init(&req->rq_list); 937 task->tk_rqstp = req; 938 xprt_request_init(task, xprt); 939 return; 940 } 941 dprintk("RPC: waiting for request slot\n"); 942 task->tk_status = -EAGAIN; 943 task->tk_timeout = 0; 944 rpc_sleep_on(&xprt->backlog, task, NULL); 945} 946 947/** 948 * xprt_reserve - allocate an RPC request slot 949 * @task: RPC task requesting a slot allocation 950 * 951 * If no more slots are available, place the task on the transport's 952 * backlog queue. 953 */ 954void xprt_reserve(struct rpc_task *task) 955{ 956 struct rpc_xprt *xprt = task->tk_xprt; 957 958 task->tk_status = -EIO; 959 spin_lock(&xprt->reserve_lock); 960 do_xprt_reserve(task); 961 spin_unlock(&xprt->reserve_lock); 962} 963 964static inline __be32 xprt_alloc_xid(struct rpc_xprt *xprt) 965{ 966 return xprt->xid++; 967} 968 969static inline void xprt_init_xid(struct rpc_xprt *xprt) 970{ 971 xprt->xid = net_random(); 972} 973 974static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt) 975{ 976 struct rpc_rqst *req = task->tk_rqstp; 977 978 req->rq_timeout = task->tk_client->cl_timeout->to_initval; 979 req->rq_task = task; 980 req->rq_xprt = xprt; 981 req->rq_buffer = NULL; 982 req->rq_xid = xprt_alloc_xid(xprt); 983 req->rq_release_snd_buf = NULL; 984 xprt_reset_majortimeo(req); 985 dprintk("RPC: %5u reserved req %p xid %08x\n", task->tk_pid, 986 req, ntohl(req->rq_xid)); 987} 988 989/** 990 * xprt_release - release an RPC request slot 991 * @task: task which is finished with the slot 992 * 993 */ 994void xprt_release(struct rpc_task *task) 995{ 996 struct rpc_xprt *xprt; 997 struct rpc_rqst *req; 998 int is_bc_request; 999 1000 if (!(req = task->tk_rqstp)) 1001 return; 1002 1003 /* Preallocated backchannel request? */ 1004 is_bc_request = bc_prealloc(req); 1005 1006 xprt = req->rq_xprt; 1007 rpc_count_iostats(task); 1008 spin_lock_bh(&xprt->transport_lock); 1009 xprt->ops->release_xprt(xprt, task); 1010 if (xprt->ops->release_request) 1011 xprt->ops->release_request(task); 1012 if (!list_empty(&req->rq_list)) 1013 list_del(&req->rq_list); 1014 xprt->last_used = jiffies; 1015 if (list_empty(&xprt->recv)) 1016 mod_timer(&xprt->timer, 1017 xprt->last_used + xprt->idle_timeout); 1018 spin_unlock_bh(&xprt->transport_lock); 1019 if (!bc_prealloc(req)) 1020 xprt->ops->buf_free(req->rq_buffer); 1021 task->tk_rqstp = NULL; 1022 if (req->rq_release_snd_buf) 1023 req->rq_release_snd_buf(req); 1024 1025 /* 1026 * Early exit if this is a backchannel preallocated request. 1027 * There is no need to have it added to the RPC slot list. 1028 */ 1029 if (is_bc_request) 1030 return; 1031 1032 memset(req, 0, sizeof(*req)); /* mark unused */ 1033 1034 dprintk("RPC: %5u release request %p\n", task->tk_pid, req); 1035 1036 spin_lock(&xprt->reserve_lock); 1037 list_add(&req->rq_list, &xprt->free); 1038 rpc_wake_up_next(&xprt->backlog); 1039 spin_unlock(&xprt->reserve_lock); 1040} 1041 1042/** 1043 * xprt_create_transport - create an RPC transport 1044 * @args: rpc transport creation arguments 1045 * 1046 */ 1047struct rpc_xprt *xprt_create_transport(struct xprt_create *args) 1048{ 1049 struct rpc_xprt *xprt; 1050 struct rpc_rqst *req; 1051 struct xprt_class *t; 1052 1053 spin_lock(&xprt_list_lock); 1054 list_for_each_entry(t, &xprt_list, list) { 1055 if (t->ident == args->ident) { 1056 spin_unlock(&xprt_list_lock); 1057 goto found; 1058 } 1059 } 1060 spin_unlock(&xprt_list_lock); 1061 printk(KERN_ERR "RPC: transport (%d) not supported\n", args->ident); 1062 return ERR_PTR(-EIO); 1063 1064found: 1065 xprt = t->setup(args); 1066 if (IS_ERR(xprt)) { 1067 dprintk("RPC: xprt_create_transport: failed, %ld\n", 1068 -PTR_ERR(xprt)); 1069 return xprt; 1070 } 1071 1072 kref_init(&xprt->kref); 1073 spin_lock_init(&xprt->transport_lock); 1074 spin_lock_init(&xprt->reserve_lock); 1075 1076 INIT_LIST_HEAD(&xprt->free); 1077 INIT_LIST_HEAD(&xprt->recv); 1078#if defined(CONFIG_NFS_V4_1) 1079 spin_lock_init(&xprt->bc_pa_lock); 1080 INIT_LIST_HEAD(&xprt->bc_pa_list); 1081#endif /* CONFIG_NFS_V4_1 */ 1082 1083 INIT_WORK(&xprt->task_cleanup, xprt_autoclose); 1084 setup_timer(&xprt->timer, xprt_init_autodisconnect, 1085 (unsigned long)xprt); 1086 xprt->last_used = jiffies; 1087 xprt->cwnd = RPC_INITCWND; 1088 xprt->bind_index = 0; 1089 1090 rpc_init_wait_queue(&xprt->binding, "xprt_binding"); 1091 rpc_init_wait_queue(&xprt->pending, "xprt_pending"); 1092 rpc_init_wait_queue(&xprt->sending, "xprt_sending"); 1093 rpc_init_wait_queue(&xprt->resend, "xprt_resend"); 1094 rpc_init_priority_wait_queue(&xprt->backlog, "xprt_backlog"); 1095 1096 /* initialize free list */ 1097 for (req = &xprt->slot[xprt->max_reqs-1]; req >= &xprt->slot[0]; req--) 1098 list_add(&req->rq_list, &xprt->free); 1099 1100 xprt_init_xid(xprt); 1101 1102 dprintk("RPC: created transport %p with %u slots\n", xprt, 1103 xprt->max_reqs); 1104 1105 return xprt; 1106} 1107 1108/** 1109 * xprt_destroy - destroy an RPC transport, killing off all requests. 1110 * @kref: kref for the transport to destroy 1111 * 1112 */ 1113static void xprt_destroy(struct kref *kref) 1114{ 1115 struct rpc_xprt *xprt = container_of(kref, struct rpc_xprt, kref); 1116 1117 dprintk("RPC: destroying transport %p\n", xprt); 1118 xprt->shutdown = 1; 1119 del_timer_sync(&xprt->timer); 1120 1121 rpc_destroy_wait_queue(&xprt->binding); 1122 rpc_destroy_wait_queue(&xprt->pending); 1123 rpc_destroy_wait_queue(&xprt->sending); 1124 rpc_destroy_wait_queue(&xprt->resend); 1125 rpc_destroy_wait_queue(&xprt->backlog); 1126 /* 1127 * Tear down transport state and free the rpc_xprt 1128 */ 1129 xprt->ops->destroy(xprt); 1130} 1131 1132/** 1133 * xprt_put - release a reference to an RPC transport. 1134 * @xprt: pointer to the transport 1135 * 1136 */ 1137void xprt_put(struct rpc_xprt *xprt) 1138{ 1139 kref_put(&xprt->kref, xprt_destroy); 1140} 1141 1142/** 1143 * xprt_get - return a reference to an RPC transport. 1144 * @xprt: pointer to the transport 1145 * 1146 */ 1147struct rpc_xprt *xprt_get(struct rpc_xprt *xprt) 1148{ 1149 kref_get(&xprt->kref); 1150 return xprt; 1151} 1152