xprt.c revision 3fa21e07e6acefa31f974d57fba2b6920a7ebd1a
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#include <linux/sunrpc/bc_xprt.h> 50 51#include "sunrpc.h" 52 53/* 54 * Local variables 55 */ 56 57#ifdef RPC_DEBUG 58# define RPCDBG_FACILITY RPCDBG_XPRT 59#endif 60 61/* 62 * Local functions 63 */ 64static void xprt_request_init(struct rpc_task *, struct rpc_xprt *); 65static inline void do_xprt_reserve(struct rpc_task *); 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 char module_name[sizeof t->name + 5]; 170 int result; 171 172 result = 0; 173 spin_lock(&xprt_list_lock); 174 list_for_each_entry(t, &xprt_list, list) { 175 if (strcmp(t->name, transport_name) == 0) { 176 spin_unlock(&xprt_list_lock); 177 goto out; 178 } 179 } 180 spin_unlock(&xprt_list_lock); 181 strcpy(module_name, "xprt"); 182 strncat(module_name, transport_name, sizeof t->name); 183 result = request_module(module_name); 184out: 185 return result; 186} 187EXPORT_SYMBOL_GPL(xprt_load_transport); 188 189/** 190 * xprt_reserve_xprt - serialize write access to transports 191 * @task: task that is requesting access to the transport 192 * 193 * This prevents mixing the payload of separate requests, and prevents 194 * transport connects from colliding with writes. No congestion control 195 * is provided. 196 */ 197int xprt_reserve_xprt(struct rpc_task *task) 198{ 199 struct rpc_rqst *req = task->tk_rqstp; 200 struct rpc_xprt *xprt = req->rq_xprt; 201 202 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) { 203 if (task == xprt->snd_task) 204 return 1; 205 if (task == NULL) 206 return 0; 207 goto out_sleep; 208 } 209 xprt->snd_task = task; 210 if (req) { 211 req->rq_bytes_sent = 0; 212 req->rq_ntrans++; 213 } 214 return 1; 215 216out_sleep: 217 dprintk("RPC: %5u failed to lock transport %p\n", 218 task->tk_pid, xprt); 219 task->tk_timeout = 0; 220 task->tk_status = -EAGAIN; 221 if (req && req->rq_ntrans) 222 rpc_sleep_on(&xprt->resend, task, NULL); 223 else 224 rpc_sleep_on(&xprt->sending, task, NULL); 225 return 0; 226} 227EXPORT_SYMBOL_GPL(xprt_reserve_xprt); 228 229static void xprt_clear_locked(struct rpc_xprt *xprt) 230{ 231 xprt->snd_task = NULL; 232 if (!test_bit(XPRT_CLOSE_WAIT, &xprt->state) || xprt->shutdown) { 233 smp_mb__before_clear_bit(); 234 clear_bit(XPRT_LOCKED, &xprt->state); 235 smp_mb__after_clear_bit(); 236 } else 237 queue_work(rpciod_workqueue, &xprt->task_cleanup); 238} 239 240/* 241 * xprt_reserve_xprt_cong - serialize write access to transports 242 * @task: task that is requesting access to the transport 243 * 244 * Same as xprt_reserve_xprt, but Van Jacobson congestion control is 245 * integrated into the decision of whether a request is allowed to be 246 * woken up and given access to the transport. 247 */ 248int xprt_reserve_xprt_cong(struct rpc_task *task) 249{ 250 struct rpc_xprt *xprt = task->tk_xprt; 251 struct rpc_rqst *req = task->tk_rqstp; 252 253 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) { 254 if (task == xprt->snd_task) 255 return 1; 256 goto out_sleep; 257 } 258 if (__xprt_get_cong(xprt, task)) { 259 xprt->snd_task = task; 260 if (req) { 261 req->rq_bytes_sent = 0; 262 req->rq_ntrans++; 263 } 264 return 1; 265 } 266 xprt_clear_locked(xprt); 267out_sleep: 268 dprintk("RPC: %5u failed to lock transport %p\n", task->tk_pid, xprt); 269 task->tk_timeout = 0; 270 task->tk_status = -EAGAIN; 271 if (req && req->rq_ntrans) 272 rpc_sleep_on(&xprt->resend, task, NULL); 273 else 274 rpc_sleep_on(&xprt->sending, task, NULL); 275 return 0; 276} 277EXPORT_SYMBOL_GPL(xprt_reserve_xprt_cong); 278 279static inline int xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task) 280{ 281 int retval; 282 283 spin_lock_bh(&xprt->transport_lock); 284 retval = xprt->ops->reserve_xprt(task); 285 spin_unlock_bh(&xprt->transport_lock); 286 return retval; 287} 288 289static void __xprt_lock_write_next(struct rpc_xprt *xprt) 290{ 291 struct rpc_task *task; 292 struct rpc_rqst *req; 293 294 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) 295 return; 296 297 task = rpc_wake_up_next(&xprt->resend); 298 if (!task) { 299 task = rpc_wake_up_next(&xprt->sending); 300 if (!task) 301 goto out_unlock; 302 } 303 304 req = task->tk_rqstp; 305 xprt->snd_task = task; 306 if (req) { 307 req->rq_bytes_sent = 0; 308 req->rq_ntrans++; 309 } 310 return; 311 312out_unlock: 313 xprt_clear_locked(xprt); 314} 315 316static void __xprt_lock_write_next_cong(struct rpc_xprt *xprt) 317{ 318 struct rpc_task *task; 319 320 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) 321 return; 322 if (RPCXPRT_CONGESTED(xprt)) 323 goto out_unlock; 324 task = rpc_wake_up_next(&xprt->resend); 325 if (!task) { 326 task = rpc_wake_up_next(&xprt->sending); 327 if (!task) 328 goto out_unlock; 329 } 330 if (__xprt_get_cong(xprt, task)) { 331 struct rpc_rqst *req = task->tk_rqstp; 332 xprt->snd_task = task; 333 if (req) { 334 req->rq_bytes_sent = 0; 335 req->rq_ntrans++; 336 } 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 = xprt->connect_timeout; 715 rpc_sleep_on(&xprt->pending, task, xprt_connect_status); 716 xprt->stat.connect_start = jiffies; 717 xprt->ops->connect(task); 718 } 719} 720 721static void xprt_connect_status(struct rpc_task *task) 722{ 723 struct rpc_xprt *xprt = task->tk_xprt; 724 725 if (task->tk_status == 0) { 726 xprt->stat.connect_count++; 727 xprt->stat.connect_time += (long)jiffies - xprt->stat.connect_start; 728 dprintk("RPC: %5u xprt_connect_status: connection established\n", 729 task->tk_pid); 730 return; 731 } 732 733 switch (task->tk_status) { 734 case -EAGAIN: 735 dprintk("RPC: %5u xprt_connect_status: retrying\n", task->tk_pid); 736 break; 737 case -ETIMEDOUT: 738 dprintk("RPC: %5u xprt_connect_status: connect attempt timed " 739 "out\n", task->tk_pid); 740 break; 741 default: 742 dprintk("RPC: %5u xprt_connect_status: error %d connecting to " 743 "server %s\n", task->tk_pid, -task->tk_status, 744 task->tk_client->cl_server); 745 xprt_release_write(xprt, task); 746 task->tk_status = -EIO; 747 } 748} 749 750/** 751 * xprt_lookup_rqst - find an RPC request corresponding to an XID 752 * @xprt: transport on which the original request was transmitted 753 * @xid: RPC XID of incoming reply 754 * 755 */ 756struct rpc_rqst *xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid) 757{ 758 struct list_head *pos; 759 760 list_for_each(pos, &xprt->recv) { 761 struct rpc_rqst *entry = list_entry(pos, struct rpc_rqst, rq_list); 762 if (entry->rq_xid == xid) 763 return entry; 764 } 765 766 dprintk("RPC: xprt_lookup_rqst did not find xid %08x\n", 767 ntohl(xid)); 768 xprt->stat.bad_xids++; 769 return NULL; 770} 771EXPORT_SYMBOL_GPL(xprt_lookup_rqst); 772 773/** 774 * xprt_update_rtt - update an RPC client's RTT state after receiving a reply 775 * @task: RPC request that recently completed 776 * 777 */ 778void xprt_update_rtt(struct rpc_task *task) 779{ 780 struct rpc_rqst *req = task->tk_rqstp; 781 struct rpc_rtt *rtt = task->tk_client->cl_rtt; 782 unsigned timer = task->tk_msg.rpc_proc->p_timer; 783 784 if (timer) { 785 if (req->rq_ntrans == 1) 786 rpc_update_rtt(rtt, timer, 787 (long)jiffies - req->rq_xtime); 788 rpc_set_timeo(rtt, timer, req->rq_ntrans - 1); 789 } 790} 791EXPORT_SYMBOL_GPL(xprt_update_rtt); 792 793/** 794 * xprt_complete_rqst - called when reply processing is complete 795 * @task: RPC request that recently completed 796 * @copied: actual number of bytes received from the transport 797 * 798 * Caller holds transport lock. 799 */ 800void xprt_complete_rqst(struct rpc_task *task, int copied) 801{ 802 struct rpc_rqst *req = task->tk_rqstp; 803 struct rpc_xprt *xprt = req->rq_xprt; 804 805 dprintk("RPC: %5u xid %08x complete (%d bytes received)\n", 806 task->tk_pid, ntohl(req->rq_xid), copied); 807 808 xprt->stat.recvs++; 809 task->tk_rtt = (long)jiffies - req->rq_xtime; 810 811 list_del_init(&req->rq_list); 812 req->rq_private_buf.len = copied; 813 /* Ensure all writes are done before we update */ 814 /* req->rq_reply_bytes_recvd */ 815 smp_wmb(); 816 req->rq_reply_bytes_recvd = copied; 817 rpc_wake_up_queued_task(&xprt->pending, task); 818} 819EXPORT_SYMBOL_GPL(xprt_complete_rqst); 820 821static void xprt_timer(struct rpc_task *task) 822{ 823 struct rpc_rqst *req = task->tk_rqstp; 824 struct rpc_xprt *xprt = req->rq_xprt; 825 826 if (task->tk_status != -ETIMEDOUT) 827 return; 828 dprintk("RPC: %5u xprt_timer\n", task->tk_pid); 829 830 spin_lock_bh(&xprt->transport_lock); 831 if (!req->rq_reply_bytes_recvd) { 832 if (xprt->ops->timer) 833 xprt->ops->timer(task); 834 } else 835 task->tk_status = 0; 836 spin_unlock_bh(&xprt->transport_lock); 837} 838 839static inline int xprt_has_timer(struct rpc_xprt *xprt) 840{ 841 return xprt->idle_timeout != 0; 842} 843 844/** 845 * xprt_prepare_transmit - reserve the transport before sending a request 846 * @task: RPC task about to send a request 847 * 848 */ 849int xprt_prepare_transmit(struct rpc_task *task) 850{ 851 struct rpc_rqst *req = task->tk_rqstp; 852 struct rpc_xprt *xprt = req->rq_xprt; 853 int err = 0; 854 855 dprintk("RPC: %5u xprt_prepare_transmit\n", task->tk_pid); 856 857 spin_lock_bh(&xprt->transport_lock); 858 if (req->rq_reply_bytes_recvd && !req->rq_bytes_sent) { 859 err = req->rq_reply_bytes_recvd; 860 goto out_unlock; 861 } 862 if (!xprt->ops->reserve_xprt(task)) 863 err = -EAGAIN; 864out_unlock: 865 spin_unlock_bh(&xprt->transport_lock); 866 return err; 867} 868 869void xprt_end_transmit(struct rpc_task *task) 870{ 871 xprt_release_write(task->tk_rqstp->rq_xprt, task); 872} 873 874/** 875 * xprt_transmit - send an RPC request on a transport 876 * @task: controlling RPC task 877 * 878 * We have to copy the iovec because sendmsg fiddles with its contents. 879 */ 880void xprt_transmit(struct rpc_task *task) 881{ 882 struct rpc_rqst *req = task->tk_rqstp; 883 struct rpc_xprt *xprt = req->rq_xprt; 884 int status; 885 886 dprintk("RPC: %5u xprt_transmit(%u)\n", task->tk_pid, req->rq_slen); 887 888 if (!req->rq_reply_bytes_recvd) { 889 if (list_empty(&req->rq_list) && rpc_reply_expected(task)) { 890 /* 891 * Add to the list only if we're expecting a reply 892 */ 893 spin_lock_bh(&xprt->transport_lock); 894 /* Update the softirq receive buffer */ 895 memcpy(&req->rq_private_buf, &req->rq_rcv_buf, 896 sizeof(req->rq_private_buf)); 897 /* Add request to the receive list */ 898 list_add_tail(&req->rq_list, &xprt->recv); 899 spin_unlock_bh(&xprt->transport_lock); 900 xprt_reset_majortimeo(req); 901 /* Turn off autodisconnect */ 902 del_singleshot_timer_sync(&xprt->timer); 903 } 904 } else if (!req->rq_bytes_sent) 905 return; 906 907 req->rq_connect_cookie = xprt->connect_cookie; 908 req->rq_xtime = jiffies; 909 status = xprt->ops->send_request(task); 910 if (status != 0) { 911 task->tk_status = status; 912 return; 913 } 914 915 dprintk("RPC: %5u xmit complete\n", task->tk_pid); 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 inline void do_xprt_reserve(struct rpc_task *task) 938{ 939 struct rpc_xprt *xprt = task->tk_xprt; 940 941 task->tk_status = 0; 942 if (task->tk_rqstp) 943 return; 944 if (!list_empty(&xprt->free)) { 945 struct rpc_rqst *req = list_entry(xprt->free.next, struct rpc_rqst, rq_list); 946 list_del_init(&req->rq_list); 947 task->tk_rqstp = req; 948 xprt_request_init(task, xprt); 949 return; 950 } 951 dprintk("RPC: waiting for request slot\n"); 952 task->tk_status = -EAGAIN; 953 task->tk_timeout = 0; 954 rpc_sleep_on(&xprt->backlog, task, NULL); 955} 956 957/** 958 * xprt_reserve - allocate an RPC request slot 959 * @task: RPC task requesting a slot allocation 960 * 961 * If no more slots are available, place the task on the transport's 962 * backlog queue. 963 */ 964void xprt_reserve(struct rpc_task *task) 965{ 966 struct rpc_xprt *xprt = task->tk_xprt; 967 968 task->tk_status = -EIO; 969 spin_lock(&xprt->reserve_lock); 970 do_xprt_reserve(task); 971 spin_unlock(&xprt->reserve_lock); 972} 973 974static inline __be32 xprt_alloc_xid(struct rpc_xprt *xprt) 975{ 976 return (__force __be32)xprt->xid++; 977} 978 979static inline void xprt_init_xid(struct rpc_xprt *xprt) 980{ 981 xprt->xid = net_random(); 982} 983 984static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt) 985{ 986 struct rpc_rqst *req = task->tk_rqstp; 987 988 req->rq_timeout = task->tk_client->cl_timeout->to_initval; 989 req->rq_task = task; 990 req->rq_xprt = xprt; 991 req->rq_buffer = NULL; 992 req->rq_xid = xprt_alloc_xid(xprt); 993 req->rq_release_snd_buf = NULL; 994 xprt_reset_majortimeo(req); 995 dprintk("RPC: %5u reserved req %p xid %08x\n", task->tk_pid, 996 req, ntohl(req->rq_xid)); 997} 998 999/** 1000 * xprt_release - release an RPC request slot 1001 * @task: task which is finished with the slot 1002 * 1003 */ 1004void xprt_release(struct rpc_task *task) 1005{ 1006 struct rpc_xprt *xprt; 1007 struct rpc_rqst *req; 1008 int is_bc_request; 1009 1010 if (!(req = task->tk_rqstp)) 1011 return; 1012 1013 /* Preallocated backchannel request? */ 1014 is_bc_request = bc_prealloc(req); 1015 1016 xprt = req->rq_xprt; 1017 rpc_count_iostats(task); 1018 spin_lock_bh(&xprt->transport_lock); 1019 xprt->ops->release_xprt(xprt, task); 1020 if (xprt->ops->release_request) 1021 xprt->ops->release_request(task); 1022 if (!list_empty(&req->rq_list)) 1023 list_del(&req->rq_list); 1024 xprt->last_used = jiffies; 1025 if (list_empty(&xprt->recv) && xprt_has_timer(xprt)) 1026 mod_timer(&xprt->timer, 1027 xprt->last_used + xprt->idle_timeout); 1028 spin_unlock_bh(&xprt->transport_lock); 1029 if (!bc_prealloc(req)) 1030 xprt->ops->buf_free(req->rq_buffer); 1031 task->tk_rqstp = NULL; 1032 if (req->rq_release_snd_buf) 1033 req->rq_release_snd_buf(req); 1034 1035 dprintk("RPC: %5u release request %p\n", task->tk_pid, req); 1036 if (likely(!is_bc_request)) { 1037 memset(req, 0, sizeof(*req)); /* mark unused */ 1038 1039 spin_lock(&xprt->reserve_lock); 1040 list_add(&req->rq_list, &xprt->free); 1041 rpc_wake_up_next(&xprt->backlog); 1042 spin_unlock(&xprt->reserve_lock); 1043 } else 1044 xprt_free_bc_request(req); 1045} 1046 1047/** 1048 * xprt_create_transport - create an RPC transport 1049 * @args: rpc transport creation arguments 1050 * 1051 */ 1052struct rpc_xprt *xprt_create_transport(struct xprt_create *args) 1053{ 1054 struct rpc_xprt *xprt; 1055 struct rpc_rqst *req; 1056 struct xprt_class *t; 1057 1058 spin_lock(&xprt_list_lock); 1059 list_for_each_entry(t, &xprt_list, list) { 1060 if (t->ident == args->ident) { 1061 spin_unlock(&xprt_list_lock); 1062 goto found; 1063 } 1064 } 1065 spin_unlock(&xprt_list_lock); 1066 printk(KERN_ERR "RPC: transport (%d) not supported\n", args->ident); 1067 return ERR_PTR(-EIO); 1068 1069found: 1070 xprt = t->setup(args); 1071 if (IS_ERR(xprt)) { 1072 dprintk("RPC: xprt_create_transport: failed, %ld\n", 1073 -PTR_ERR(xprt)); 1074 return xprt; 1075 } 1076 1077 kref_init(&xprt->kref); 1078 spin_lock_init(&xprt->transport_lock); 1079 spin_lock_init(&xprt->reserve_lock); 1080 1081 INIT_LIST_HEAD(&xprt->free); 1082 INIT_LIST_HEAD(&xprt->recv); 1083#if defined(CONFIG_NFS_V4_1) 1084 spin_lock_init(&xprt->bc_pa_lock); 1085 INIT_LIST_HEAD(&xprt->bc_pa_list); 1086#endif /* CONFIG_NFS_V4_1 */ 1087 1088 INIT_WORK(&xprt->task_cleanup, xprt_autoclose); 1089 if (xprt_has_timer(xprt)) 1090 setup_timer(&xprt->timer, xprt_init_autodisconnect, 1091 (unsigned long)xprt); 1092 else 1093 init_timer(&xprt->timer); 1094 xprt->last_used = jiffies; 1095 xprt->cwnd = RPC_INITCWND; 1096 xprt->bind_index = 0; 1097 1098 rpc_init_wait_queue(&xprt->binding, "xprt_binding"); 1099 rpc_init_wait_queue(&xprt->pending, "xprt_pending"); 1100 rpc_init_wait_queue(&xprt->sending, "xprt_sending"); 1101 rpc_init_wait_queue(&xprt->resend, "xprt_resend"); 1102 rpc_init_priority_wait_queue(&xprt->backlog, "xprt_backlog"); 1103 1104 /* initialize free list */ 1105 for (req = &xprt->slot[xprt->max_reqs-1]; req >= &xprt->slot[0]; req--) 1106 list_add(&req->rq_list, &xprt->free); 1107 1108 xprt_init_xid(xprt); 1109 1110 dprintk("RPC: created transport %p with %u slots\n", xprt, 1111 xprt->max_reqs); 1112 return xprt; 1113} 1114 1115/** 1116 * xprt_destroy - destroy an RPC transport, killing off all requests. 1117 * @kref: kref for the transport to destroy 1118 * 1119 */ 1120static void xprt_destroy(struct kref *kref) 1121{ 1122 struct rpc_xprt *xprt = container_of(kref, struct rpc_xprt, kref); 1123 1124 dprintk("RPC: destroying transport %p\n", xprt); 1125 xprt->shutdown = 1; 1126 del_timer_sync(&xprt->timer); 1127 1128 rpc_destroy_wait_queue(&xprt->binding); 1129 rpc_destroy_wait_queue(&xprt->pending); 1130 rpc_destroy_wait_queue(&xprt->sending); 1131 rpc_destroy_wait_queue(&xprt->resend); 1132 rpc_destroy_wait_queue(&xprt->backlog); 1133 /* 1134 * Tear down transport state and free the rpc_xprt 1135 */ 1136 xprt->ops->destroy(xprt); 1137} 1138 1139/** 1140 * xprt_put - release a reference to an RPC transport. 1141 * @xprt: pointer to the transport 1142 * 1143 */ 1144void xprt_put(struct rpc_xprt *xprt) 1145{ 1146 kref_put(&xprt->kref, xprt_destroy); 1147} 1148 1149/** 1150 * xprt_get - return a reference to an RPC transport. 1151 * @xprt: pointer to the transport 1152 * 1153 */ 1154struct rpc_xprt *xprt_get(struct rpc_xprt *xprt) 1155{ 1156 kref_get(&xprt->kref); 1157 return xprt; 1158} 1159