1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  linux/net/sunrpc/xprt.c
   4 *
   5 *  This is a generic RPC call interface supporting congestion avoidance,
   6 *  and asynchronous calls.
   7 *
   8 *  The interface works like this:
   9 *
  10 *  -	When a process places a call, it allocates a request slot if
  11 *	one is available. Otherwise, it sleeps on the backlog queue
  12 *	(xprt_reserve).
  13 *  -	Next, the caller puts together the RPC message, stuffs it into
  14 *	the request struct, and calls xprt_transmit().
  15 *  -	xprt_transmit sends the message and installs the caller on the
  16 *	transport's wait list. At the same time, if a reply is expected,
  17 *	it installs a timer that is run after the packet's timeout has
  18 *	expired.
  19 *  -	When a packet arrives, the data_ready handler walks the list of
  20 *	pending requests for that transport. If a matching XID is found, the
  21 *	caller is woken up, and the timer removed.
  22 *  -	When no reply arrives within the timeout interval, the timer is
  23 *	fired by the kernel and runs xprt_timer(). It either adjusts the
  24 *	timeout values (minor timeout) or wakes up the caller with a status
  25 *	of -ETIMEDOUT.
  26 *  -	When the caller receives a notification from RPC that a reply arrived,
  27 *	it should release the RPC slot, and process the reply.
  28 *	If the call timed out, it may choose to retry the operation by
  29 *	adjusting the initial timeout value, and simply calling rpc_call
  30 *	again.
  31 *
  32 *  Support for async RPC is done through a set of RPC-specific scheduling
  33 *  primitives that `transparently' work for processes as well as async
  34 *  tasks that rely on callbacks.
  35 *
  36 *  Copyright (C) 1995-1997, Olaf Kirch <okir@monad.swb.de>
  37 *
  38 *  Transport switch API copyright (C) 2005, Chuck Lever <cel@netapp.com>
  39 */
  40
  41#include <linux/module.h>
  42
  43#include <linux/types.h>
  44#include <linux/interrupt.h>
  45#include <linux/workqueue.h>
  46#include <linux/net.h>
  47#include <linux/ktime.h>
  48
  49#include <linux/sunrpc/clnt.h>
  50#include <linux/sunrpc/metrics.h>
  51#include <linux/sunrpc/bc_xprt.h>
  52#include <linux/rcupdate.h>
  53#include <linux/sched/mm.h>
  54
  55#include <trace/events/sunrpc.h>
  56
  57#include "sunrpc.h"
  58#include "sysfs.h"
  59#include "fail.h"
  60
  61/*
  62 * Local variables
  63 */
  64
  65#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
  66# define RPCDBG_FACILITY	RPCDBG_XPRT
  67#endif
  68
  69/*
  70 * Local functions
  71 */
  72static void	xprt_init(struct rpc_xprt *xprt, struct net *net);
  73static __be32	xprt_alloc_xid(struct rpc_xprt *xprt);
  74static void	xprt_destroy(struct rpc_xprt *xprt);
  75static void	xprt_request_init(struct rpc_task *task);
  76static int	xprt_request_prepare(struct rpc_rqst *req, struct xdr_buf *buf);
  77
  78static DEFINE_SPINLOCK(xprt_list_lock);
  79static LIST_HEAD(xprt_list);
  80
  81static unsigned long xprt_request_timeout(const struct rpc_rqst *req)
  82{
  83	unsigned long timeout = jiffies + req->rq_timeout;
  84
  85	if (time_before(timeout, req->rq_majortimeo))
  86		return timeout;
  87	return req->rq_majortimeo;
  88}
  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
 158static void
 159xprt_class_release(const struct xprt_class *t)
 160{
 161	module_put(t->owner);
 162}
 163
 164static const struct xprt_class *
 165xprt_class_find_by_ident_locked(int ident)
 166{
 167	const struct xprt_class *t;
 168
 169	list_for_each_entry(t, &xprt_list, list) {
 170		if (t->ident != ident)
 171			continue;
 172		if (!try_module_get(t->owner))
 173			continue;
 174		return t;
 175	}
 176	return NULL;
 177}
 178
 179static const struct xprt_class *
 180xprt_class_find_by_ident(int ident)
 181{
 182	const struct xprt_class *t;
 183
 184	spin_lock(&xprt_list_lock);
 185	t = xprt_class_find_by_ident_locked(ident);
 186	spin_unlock(&xprt_list_lock);
 187	return t;
 188}
 189
 190static const struct xprt_class *
 191xprt_class_find_by_netid_locked(const char *netid)
 192{
 193	const struct xprt_class *t;
 194	unsigned int i;
 195
 196	list_for_each_entry(t, &xprt_list, list) {
 197		for (i = 0; t->netid[i][0] != '\0'; i++) {
 198			if (strcmp(t->netid[i], netid) != 0)
 199				continue;
 200			if (!try_module_get(t->owner))
 201				continue;
 202			return t;
 203		}
 204	}
 205	return NULL;
 206}
 207
 208static const struct xprt_class *
 209xprt_class_find_by_netid(const char *netid)
 210{
 211	const struct xprt_class *t;
 212
 213	spin_lock(&xprt_list_lock);
 214	t = xprt_class_find_by_netid_locked(netid);
 215	if (!t) {
 216		spin_unlock(&xprt_list_lock);
 217		request_module("rpc%s", netid);
 218		spin_lock(&xprt_list_lock);
 219		t = xprt_class_find_by_netid_locked(netid);
 220	}
 221	spin_unlock(&xprt_list_lock);
 222	return t;
 223}
 224
 225/**
 226 * xprt_find_transport_ident - convert a netid into a transport identifier
 227 * @netid: transport to load
 228 *
 229 * Returns:
 230 * > 0:		transport identifier
 231 * -ENOENT:	transport module not available
 232 */
 233int xprt_find_transport_ident(const char *netid)
 234{
 235	const struct xprt_class *t;
 236	int ret;
 237
 238	t = xprt_class_find_by_netid(netid);
 239	if (!t)
 240		return -ENOENT;
 241	ret = t->ident;
 242	xprt_class_release(t);
 243	return ret;
 244}
 245EXPORT_SYMBOL_GPL(xprt_find_transport_ident);
 246
 247static void xprt_clear_locked(struct rpc_xprt *xprt)
 248{
 249	xprt->snd_task = NULL;
 250	if (!test_bit(XPRT_CLOSE_WAIT, &xprt->state))
 251		clear_bit_unlock(XPRT_LOCKED, &xprt->state);
 252	else
 253		queue_work(xprtiod_workqueue, &xprt->task_cleanup);
 254}
 255
 256/**
 257 * xprt_reserve_xprt - serialize write access to transports
 258 * @task: task that is requesting access to the transport
 259 * @xprt: pointer to the target transport
 260 *
 261 * This prevents mixing the payload of separate requests, and prevents
 262 * transport connects from colliding with writes.  No congestion control
 263 * is provided.
 264 */
 265int xprt_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
 266{
 267	struct rpc_rqst *req = task->tk_rqstp;
 268
 269	if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {
 270		if (task == xprt->snd_task)
 271			goto out_locked;
 272		goto out_sleep;
 273	}
 274	if (test_bit(XPRT_WRITE_SPACE, &xprt->state))
 275		goto out_unlock;
 276	xprt->snd_task = task;
 277
 278out_locked:
 279	trace_xprt_reserve_xprt(xprt, task);
 280	return 1;
 281
 282out_unlock:
 283	xprt_clear_locked(xprt);
 284out_sleep:
 285	task->tk_status = -EAGAIN;
 286	if (RPC_IS_SOFT(task) || RPC_IS_SOFTCONN(task))
 287		rpc_sleep_on_timeout(&xprt->sending, task, NULL,
 288				xprt_request_timeout(req));
 289	else
 290		rpc_sleep_on(&xprt->sending, task, NULL);
 291	return 0;
 292}
 293EXPORT_SYMBOL_GPL(xprt_reserve_xprt);
 294
 295static bool
 296xprt_need_congestion_window_wait(struct rpc_xprt *xprt)
 297{
 298	return test_bit(XPRT_CWND_WAIT, &xprt->state);
 299}
 300
 301static void
 302xprt_set_congestion_window_wait(struct rpc_xprt *xprt)
 303{
 304	if (!list_empty(&xprt->xmit_queue)) {
 305		/* Peek at head of queue to see if it can make progress */
 306		if (list_first_entry(&xprt->xmit_queue, struct rpc_rqst,
 307					rq_xmit)->rq_cong)
 308			return;
 309	}
 310	set_bit(XPRT_CWND_WAIT, &xprt->state);
 311}
 312
 313static void
 314xprt_test_and_clear_congestion_window_wait(struct rpc_xprt *xprt)
 315{
 316	if (!RPCXPRT_CONGESTED(xprt))
 317		clear_bit(XPRT_CWND_WAIT, &xprt->state);
 318}
 319
 320/*
 321 * xprt_reserve_xprt_cong - serialize write access to transports
 322 * @task: task that is requesting access to the transport
 323 *
 324 * Same as xprt_reserve_xprt, but Van Jacobson congestion control is
 325 * integrated into the decision of whether a request is allowed to be
 326 * woken up and given access to the transport.
 327 * Note that the lock is only granted if we know there are free slots.
 328 */
 329int xprt_reserve_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task)
 330{
 331	struct rpc_rqst *req = task->tk_rqstp;
 332
 333	if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {
 334		if (task == xprt->snd_task)
 335			goto out_locked;
 336		goto out_sleep;
 337	}
 338	if (req == NULL) {
 339		xprt->snd_task = task;
 340		goto out_locked;
 341	}
 342	if (test_bit(XPRT_WRITE_SPACE, &xprt->state))
 343		goto out_unlock;
 344	if (!xprt_need_congestion_window_wait(xprt)) {
 345		xprt->snd_task = task;
 346		goto out_locked;
 347	}
 348out_unlock:
 349	xprt_clear_locked(xprt);
 350out_sleep:
 351	task->tk_status = -EAGAIN;
 352	if (RPC_IS_SOFT(task) || RPC_IS_SOFTCONN(task))
 353		rpc_sleep_on_timeout(&xprt->sending, task, NULL,
 354				xprt_request_timeout(req));
 355	else
 356		rpc_sleep_on(&xprt->sending, task, NULL);
 357	return 0;
 358out_locked:
 359	trace_xprt_reserve_cong(xprt, task);
 360	return 1;
 361}
 362EXPORT_SYMBOL_GPL(xprt_reserve_xprt_cong);
 363
 364static inline int xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task)
 365{
 366	int retval;
 367
 368	if (test_bit(XPRT_LOCKED, &xprt->state) && xprt->snd_task == task)
 369		return 1;
 370	spin_lock(&xprt->transport_lock);
 371	retval = xprt->ops->reserve_xprt(xprt, task);
 372	spin_unlock(&xprt->transport_lock);
 373	return retval;
 374}
 375
 376static bool __xprt_lock_write_func(struct rpc_task *task, void *data)
 377{
 378	struct rpc_xprt *xprt = data;
 379
 380	xprt->snd_task = task;
 381	return true;
 382}
 383
 384static void __xprt_lock_write_next(struct rpc_xprt *xprt)
 385{
 386	if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
 387		return;
 388	if (test_bit(XPRT_WRITE_SPACE, &xprt->state))
 389		goto out_unlock;
 390	if (rpc_wake_up_first_on_wq(xprtiod_workqueue, &xprt->sending,
 391				__xprt_lock_write_func, xprt))
 392		return;
 393out_unlock:
 394	xprt_clear_locked(xprt);
 395}
 396
 397static void __xprt_lock_write_next_cong(struct rpc_xprt *xprt)
 398{
 399	if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
 400		return;
 401	if (test_bit(XPRT_WRITE_SPACE, &xprt->state))
 402		goto out_unlock;
 403	if (xprt_need_congestion_window_wait(xprt))
 404		goto out_unlock;
 405	if (rpc_wake_up_first_on_wq(xprtiod_workqueue, &xprt->sending,
 406				__xprt_lock_write_func, xprt))
 407		return;
 408out_unlock:
 409	xprt_clear_locked(xprt);
 410}
 411
 412/**
 413 * xprt_release_xprt - allow other requests to use a transport
 414 * @xprt: transport with other tasks potentially waiting
 415 * @task: task that is releasing access to the transport
 416 *
 417 * Note that "task" can be NULL.  No congestion control is provided.
 418 */
 419void xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
 420{
 421	if (xprt->snd_task == task) {
 422		xprt_clear_locked(xprt);
 423		__xprt_lock_write_next(xprt);
 424	}
 425	trace_xprt_release_xprt(xprt, task);
 426}
 427EXPORT_SYMBOL_GPL(xprt_release_xprt);
 428
 429/**
 430 * xprt_release_xprt_cong - allow other requests to use a transport
 431 * @xprt: transport with other tasks potentially waiting
 432 * @task: task that is releasing access to the transport
 433 *
 434 * Note that "task" can be NULL.  Another task is awoken to use the
 435 * transport if the transport's congestion window allows it.
 436 */
 437void xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task)
 438{
 439	if (xprt->snd_task == task) {
 440		xprt_clear_locked(xprt);
 441		__xprt_lock_write_next_cong(xprt);
 442	}
 443	trace_xprt_release_cong(xprt, task);
 444}
 445EXPORT_SYMBOL_GPL(xprt_release_xprt_cong);
 446
 447void xprt_release_write(struct rpc_xprt *xprt, struct rpc_task *task)
 448{
 449	if (xprt->snd_task != task)
 450		return;
 451	spin_lock(&xprt->transport_lock);
 452	xprt->ops->release_xprt(xprt, task);
 453	spin_unlock(&xprt->transport_lock);
 454}
 455
 456/*
 457 * Van Jacobson congestion avoidance. Check if the congestion window
 458 * overflowed. Put the task to sleep if this is the case.
 459 */
 460static int
 461__xprt_get_cong(struct rpc_xprt *xprt, struct rpc_rqst *req)
 462{
 463	if (req->rq_cong)
 464		return 1;
 465	trace_xprt_get_cong(xprt, req->rq_task);
 466	if (RPCXPRT_CONGESTED(xprt)) {
 467		xprt_set_congestion_window_wait(xprt);
 468		return 0;
 469	}
 470	req->rq_cong = 1;
 471	xprt->cong += RPC_CWNDSCALE;
 472	return 1;
 473}
 474
 475/*
 476 * Adjust the congestion window, and wake up the next task
 477 * that has been sleeping due to congestion
 478 */
 479static void
 480__xprt_put_cong(struct rpc_xprt *xprt, struct rpc_rqst *req)
 481{
 482	if (!req->rq_cong)
 483		return;
 484	req->rq_cong = 0;
 485	xprt->cong -= RPC_CWNDSCALE;
 486	xprt_test_and_clear_congestion_window_wait(xprt);
 487	trace_xprt_put_cong(xprt, req->rq_task);
 488	__xprt_lock_write_next_cong(xprt);
 489}
 490
 491/**
 492 * xprt_request_get_cong - Request congestion control credits
 493 * @xprt: pointer to transport
 494 * @req: pointer to RPC request
 495 *
 496 * Useful for transports that require congestion control.
 497 */
 498bool
 499xprt_request_get_cong(struct rpc_xprt *xprt, struct rpc_rqst *req)
 500{
 501	bool ret = false;
 502
 503	if (req->rq_cong)
 504		return true;
 505	spin_lock(&xprt->transport_lock);
 506	ret = __xprt_get_cong(xprt, req) != 0;
 507	spin_unlock(&xprt->transport_lock);
 508	return ret;
 509}
 510EXPORT_SYMBOL_GPL(xprt_request_get_cong);
 511
 512/**
 513 * xprt_release_rqst_cong - housekeeping when request is complete
 514 * @task: RPC request that recently completed
 515 *
 516 * Useful for transports that require congestion control.
 517 */
 518void xprt_release_rqst_cong(struct rpc_task *task)
 519{
 520	struct rpc_rqst *req = task->tk_rqstp;
 521
 522	__xprt_put_cong(req->rq_xprt, req);
 523}
 524EXPORT_SYMBOL_GPL(xprt_release_rqst_cong);
 525
 526static void xprt_clear_congestion_window_wait_locked(struct rpc_xprt *xprt)
 527{
 528	if (test_and_clear_bit(XPRT_CWND_WAIT, &xprt->state))
 529		__xprt_lock_write_next_cong(xprt);
 530}
 531
 532/*
 533 * Clear the congestion window wait flag and wake up the next
 534 * entry on xprt->sending
 535 */
 536static void
 537xprt_clear_congestion_window_wait(struct rpc_xprt *xprt)
 538{
 539	if (test_and_clear_bit(XPRT_CWND_WAIT, &xprt->state)) {
 540		spin_lock(&xprt->transport_lock);
 541		__xprt_lock_write_next_cong(xprt);
 542		spin_unlock(&xprt->transport_lock);
 543	}
 544}
 545
 546/**
 547 * xprt_adjust_cwnd - adjust transport congestion window
 548 * @xprt: pointer to xprt
 549 * @task: recently completed RPC request used to adjust window
 550 * @result: result code of completed RPC request
 551 *
 552 * The transport code maintains an estimate on the maximum number of out-
 553 * standing RPC requests, using a smoothed version of the congestion
 554 * avoidance implemented in 44BSD. This is basically the Van Jacobson
 555 * congestion algorithm: If a retransmit occurs, the congestion window is
 556 * halved; otherwise, it is incremented by 1/cwnd when
 557 *
 558 *	-	a reply is received and
 559 *	-	a full number of requests are outstanding and
 560 *	-	the congestion window hasn't been updated recently.
 561 */
 562void xprt_adjust_cwnd(struct rpc_xprt *xprt, struct rpc_task *task, int result)
 563{
 564	struct rpc_rqst *req = task->tk_rqstp;
 565	unsigned long cwnd = xprt->cwnd;
 566
 567	if (result >= 0 && cwnd <= xprt->cong) {
 568		/* The (cwnd >> 1) term makes sure
 569		 * the result gets rounded properly. */
 570		cwnd += (RPC_CWNDSCALE * RPC_CWNDSCALE + (cwnd >> 1)) / cwnd;
 571		if (cwnd > RPC_MAXCWND(xprt))
 572			cwnd = RPC_MAXCWND(xprt);
 573		__xprt_lock_write_next_cong(xprt);
 574	} else if (result == -ETIMEDOUT) {
 575		cwnd >>= 1;
 576		if (cwnd < RPC_CWNDSCALE)
 577			cwnd = RPC_CWNDSCALE;
 578	}
 579	dprintk("RPC:       cong %ld, cwnd was %ld, now %ld\n",
 580			xprt->cong, xprt->cwnd, cwnd);
 581	xprt->cwnd = cwnd;
 582	__xprt_put_cong(xprt, req);
 583}
 584EXPORT_SYMBOL_GPL(xprt_adjust_cwnd);
 585
 586/**
 587 * xprt_wake_pending_tasks - wake all tasks on a transport's pending queue
 588 * @xprt: transport with waiting tasks
 589 * @status: result code to plant in each task before waking it
 590 *
 591 */
 592void xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status)
 593{
 594	if (status < 0)
 595		rpc_wake_up_status(&xprt->pending, status);
 596	else
 597		rpc_wake_up(&xprt->pending);
 598}
 599EXPORT_SYMBOL_GPL(xprt_wake_pending_tasks);
 600
 601/**
 602 * xprt_wait_for_buffer_space - wait for transport output buffer to clear
 603 * @xprt: transport
 604 *
 605 * Note that we only set the timer for the case of RPC_IS_SOFT(), since
 606 * we don't in general want to force a socket disconnection due to
 607 * an incomplete RPC call transmission.
 608 */
 609void xprt_wait_for_buffer_space(struct rpc_xprt *xprt)
 610{
 611	set_bit(XPRT_WRITE_SPACE, &xprt->state);
 612}
 613EXPORT_SYMBOL_GPL(xprt_wait_for_buffer_space);
 614
 615static bool
 616xprt_clear_write_space_locked(struct rpc_xprt *xprt)
 617{
 618	if (test_and_clear_bit(XPRT_WRITE_SPACE, &xprt->state)) {
 619		__xprt_lock_write_next(xprt);
 620		dprintk("RPC:       write space: waking waiting task on "
 621				"xprt %p\n", xprt);
 622		return true;
 623	}
 624	return false;
 625}
 626
 627/**
 628 * xprt_write_space - wake the task waiting for transport output buffer space
 629 * @xprt: transport with waiting tasks
 630 *
 631 * Can be called in a soft IRQ context, so xprt_write_space never sleeps.
 632 */
 633bool xprt_write_space(struct rpc_xprt *xprt)
 634{
 635	bool ret;
 636
 637	if (!test_bit(XPRT_WRITE_SPACE, &xprt->state))
 638		return false;
 639	spin_lock(&xprt->transport_lock);
 640	ret = xprt_clear_write_space_locked(xprt);
 641	spin_unlock(&xprt->transport_lock);
 642	return ret;
 643}
 644EXPORT_SYMBOL_GPL(xprt_write_space);
 645
 646static unsigned long xprt_abs_ktime_to_jiffies(ktime_t abstime)
 647{
 648	s64 delta = ktime_to_ns(ktime_get() - abstime);
 649	return likely(delta >= 0) ?
 650		jiffies - nsecs_to_jiffies(delta) :
 651		jiffies + nsecs_to_jiffies(-delta);
 652}
 653
 654static unsigned long xprt_calc_majortimeo(struct rpc_rqst *req,
 655		const struct rpc_timeout *to)
 656{
 
 657	unsigned long majortimeo = req->rq_timeout;
 658
 659	if (to->to_exponential)
 660		majortimeo <<= to->to_retries;
 661	else
 662		majortimeo += to->to_increment * to->to_retries;
 663	if (majortimeo > to->to_maxval || majortimeo == 0)
 664		majortimeo = to->to_maxval;
 665	return majortimeo;
 666}
 667
 668static void xprt_reset_majortimeo(struct rpc_rqst *req,
 669		const struct rpc_timeout *to)
 670{
 671	req->rq_majortimeo += xprt_calc_majortimeo(req, to);
 672}
 673
 674static void xprt_reset_minortimeo(struct rpc_rqst *req)
 675{
 676	req->rq_minortimeo += req->rq_timeout;
 677}
 678
 679static void xprt_init_majortimeo(struct rpc_task *task, struct rpc_rqst *req,
 680		const struct rpc_timeout *to)
 681{
 682	unsigned long time_init;
 683	struct rpc_xprt *xprt = req->rq_xprt;
 684
 685	if (likely(xprt && xprt_connected(xprt)))
 686		time_init = jiffies;
 687	else
 688		time_init = xprt_abs_ktime_to_jiffies(task->tk_start);
 689
 690	req->rq_timeout = to->to_initval;
 691	req->rq_majortimeo = time_init + xprt_calc_majortimeo(req, to);
 692	req->rq_minortimeo = time_init + req->rq_timeout;
 693}
 694
 695/**
 696 * xprt_adjust_timeout - adjust timeout values for next retransmit
 697 * @req: RPC request containing parameters to use for the adjustment
 698 *
 699 */
 700int xprt_adjust_timeout(struct rpc_rqst *req)
 701{
 702	struct rpc_xprt *xprt = req->rq_xprt;
 703	const struct rpc_timeout *to = req->rq_task->tk_client->cl_timeout;
 704	int status = 0;
 705
 706	if (time_before(jiffies, req->rq_majortimeo)) {
 707		if (time_before(jiffies, req->rq_minortimeo))
 708			return status;
 709		if (to->to_exponential)
 710			req->rq_timeout <<= 1;
 711		else
 712			req->rq_timeout += to->to_increment;
 713		if (to->to_maxval && req->rq_timeout >= to->to_maxval)
 714			req->rq_timeout = to->to_maxval;
 715		req->rq_retries++;
 716	} else {
 717		req->rq_timeout = to->to_initval;
 718		req->rq_retries = 0;
 719		xprt_reset_majortimeo(req, to);
 720		/* Reset the RTT counters == "slow start" */
 721		spin_lock(&xprt->transport_lock);
 722		rpc_init_rtt(req->rq_task->tk_client->cl_rtt, to->to_initval);
 723		spin_unlock(&xprt->transport_lock);
 724		status = -ETIMEDOUT;
 725	}
 726	xprt_reset_minortimeo(req);
 727
 728	if (req->rq_timeout == 0) {
 729		printk(KERN_WARNING "xprt_adjust_timeout: rq_timeout = 0!\n");
 730		req->rq_timeout = 5 * HZ;
 731	}
 732	return status;
 733}
 734
 735static void xprt_autoclose(struct work_struct *work)
 736{
 737	struct rpc_xprt *xprt =
 738		container_of(work, struct rpc_xprt, task_cleanup);
 739	unsigned int pflags = memalloc_nofs_save();
 740
 741	trace_xprt_disconnect_auto(xprt);
 742	xprt->connect_cookie++;
 743	smp_mb__before_atomic();
 744	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
 745	xprt->ops->close(xprt);
 746	xprt_release_write(xprt, NULL);
 747	wake_up_bit(&xprt->state, XPRT_LOCKED);
 748	memalloc_nofs_restore(pflags);
 749}
 750
 751/**
 752 * xprt_disconnect_done - mark a transport as disconnected
 753 * @xprt: transport to flag for disconnect
 754 *
 755 */
 756void xprt_disconnect_done(struct rpc_xprt *xprt)
 757{
 758	trace_xprt_disconnect_done(xprt);
 759	spin_lock(&xprt->transport_lock);
 760	xprt_clear_connected(xprt);
 761	xprt_clear_write_space_locked(xprt);
 762	xprt_clear_congestion_window_wait_locked(xprt);
 763	xprt_wake_pending_tasks(xprt, -ENOTCONN);
 764	spin_unlock(&xprt->transport_lock);
 765}
 766EXPORT_SYMBOL_GPL(xprt_disconnect_done);
 767
 768/**
 769 * xprt_schedule_autoclose_locked - Try to schedule an autoclose RPC call
 770 * @xprt: transport to disconnect
 771 */
 772static void xprt_schedule_autoclose_locked(struct rpc_xprt *xprt)
 773{
 774	if (test_and_set_bit(XPRT_CLOSE_WAIT, &xprt->state))
 775		return;
 776	if (test_and_set_bit(XPRT_LOCKED, &xprt->state) == 0)
 777		queue_work(xprtiod_workqueue, &xprt->task_cleanup);
 778	else if (xprt->snd_task && !test_bit(XPRT_SND_IS_COOKIE, &xprt->state))
 779		rpc_wake_up_queued_task_set_status(&xprt->pending,
 780						   xprt->snd_task, -ENOTCONN);
 781}
 782
 783/**
 784 * xprt_force_disconnect - force a transport to disconnect
 785 * @xprt: transport to disconnect
 786 *
 787 */
 788void xprt_force_disconnect(struct rpc_xprt *xprt)
 789{
 790	trace_xprt_disconnect_force(xprt);
 791
 792	/* Don't race with the test_bit() in xprt_clear_locked() */
 793	spin_lock(&xprt->transport_lock);
 794	xprt_schedule_autoclose_locked(xprt);
 795	spin_unlock(&xprt->transport_lock);
 796}
 797EXPORT_SYMBOL_GPL(xprt_force_disconnect);
 798
 799static unsigned int
 800xprt_connect_cookie(struct rpc_xprt *xprt)
 801{
 802	return READ_ONCE(xprt->connect_cookie);
 803}
 804
 805static bool
 806xprt_request_retransmit_after_disconnect(struct rpc_task *task)
 807{
 808	struct rpc_rqst *req = task->tk_rqstp;
 809	struct rpc_xprt *xprt = req->rq_xprt;
 810
 811	return req->rq_connect_cookie != xprt_connect_cookie(xprt) ||
 812		!xprt_connected(xprt);
 813}
 814
 815/**
 816 * xprt_conditional_disconnect - force a transport to disconnect
 817 * @xprt: transport to disconnect
 818 * @cookie: 'connection cookie'
 819 *
 820 * This attempts to break the connection if and only if 'cookie' matches
 821 * the current transport 'connection cookie'. It ensures that we don't
 822 * try to break the connection more than once when we need to retransmit
 823 * a batch of RPC requests.
 824 *
 825 */
 826void xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie)
 827{
 828	/* Don't race with the test_bit() in xprt_clear_locked() */
 829	spin_lock(&xprt->transport_lock);
 830	if (cookie != xprt->connect_cookie)
 831		goto out;
 832	if (test_bit(XPRT_CLOSING, &xprt->state))
 833		goto out;
 834	xprt_schedule_autoclose_locked(xprt);
 835out:
 836	spin_unlock(&xprt->transport_lock);
 837}
 838
 839static bool
 840xprt_has_timer(const struct rpc_xprt *xprt)
 841{
 842	return xprt->idle_timeout != 0;
 843}
 844
 845static void
 846xprt_schedule_autodisconnect(struct rpc_xprt *xprt)
 847	__must_hold(&xprt->transport_lock)
 848{
 849	xprt->last_used = jiffies;
 850	if (RB_EMPTY_ROOT(&xprt->recv_queue) && xprt_has_timer(xprt))
 851		mod_timer(&xprt->timer, xprt->last_used + xprt->idle_timeout);
 852}
 853
 854static void
 855xprt_init_autodisconnect(struct timer_list *t)
 856{
 857	struct rpc_xprt *xprt = from_timer(xprt, t, timer);
 858
 859	if (!RB_EMPTY_ROOT(&xprt->recv_queue))
 860		return;
 861	/* Reset xprt->last_used to avoid connect/autodisconnect cycling */
 862	xprt->last_used = jiffies;
 863	if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
 864		return;
 865	queue_work(xprtiod_workqueue, &xprt->task_cleanup);
 866}
 867
 868#if IS_ENABLED(CONFIG_FAIL_SUNRPC)
 869static void xprt_inject_disconnect(struct rpc_xprt *xprt)
 870{
 871	if (!fail_sunrpc.ignore_client_disconnect &&
 872	    should_fail(&fail_sunrpc.attr, 1))
 873		xprt->ops->inject_disconnect(xprt);
 874}
 875#else
 876static inline void xprt_inject_disconnect(struct rpc_xprt *xprt)
 877{
 878}
 879#endif
 880
 881bool xprt_lock_connect(struct rpc_xprt *xprt,
 882		struct rpc_task *task,
 883		void *cookie)
 884{
 885	bool ret = false;
 886
 887	spin_lock(&xprt->transport_lock);
 888	if (!test_bit(XPRT_LOCKED, &xprt->state))
 889		goto out;
 890	if (xprt->snd_task != task)
 891		goto out;
 892	set_bit(XPRT_SND_IS_COOKIE, &xprt->state);
 893	xprt->snd_task = cookie;
 894	ret = true;
 895out:
 896	spin_unlock(&xprt->transport_lock);
 897	return ret;
 898}
 899EXPORT_SYMBOL_GPL(xprt_lock_connect);
 900
 901void xprt_unlock_connect(struct rpc_xprt *xprt, void *cookie)
 902{
 903	spin_lock(&xprt->transport_lock);
 904	if (xprt->snd_task != cookie)
 905		goto out;
 906	if (!test_bit(XPRT_LOCKED, &xprt->state))
 907		goto out;
 908	xprt->snd_task =NULL;
 909	clear_bit(XPRT_SND_IS_COOKIE, &xprt->state);
 910	xprt->ops->release_xprt(xprt, NULL);
 911	xprt_schedule_autodisconnect(xprt);
 912out:
 913	spin_unlock(&xprt->transport_lock);
 914	wake_up_bit(&xprt->state, XPRT_LOCKED);
 915}
 916EXPORT_SYMBOL_GPL(xprt_unlock_connect);
 917
 918/**
 919 * xprt_connect - schedule a transport connect operation
 920 * @task: RPC task that is requesting the connect
 921 *
 922 */
 923void xprt_connect(struct rpc_task *task)
 924{
 925	struct rpc_xprt	*xprt = task->tk_rqstp->rq_xprt;
 926
 927	trace_xprt_connect(xprt);
 928
 929	if (!xprt_bound(xprt)) {
 930		task->tk_status = -EAGAIN;
 931		return;
 932	}
 933	if (!xprt_lock_write(xprt, task))
 934		return;
 935
 936	if (!xprt_connected(xprt) && !test_bit(XPRT_CLOSE_WAIT, &xprt->state)) {
 937		task->tk_rqstp->rq_connect_cookie = xprt->connect_cookie;
 938		rpc_sleep_on_timeout(&xprt->pending, task, NULL,
 939				xprt_request_timeout(task->tk_rqstp));
 940
 941		if (test_bit(XPRT_CLOSING, &xprt->state))
 942			return;
 943		if (xprt_test_and_set_connecting(xprt))
 944			return;
 945		/* Race breaker */
 946		if (!xprt_connected(xprt)) {
 947			xprt->stat.connect_start = jiffies;
 948			xprt->ops->connect(xprt, task);
 949		} else {
 950			xprt_clear_connecting(xprt);
 951			task->tk_status = 0;
 952			rpc_wake_up_queued_task(&xprt->pending, task);
 953		}
 954	}
 955	xprt_release_write(xprt, task);
 956}
 957
 958/**
 959 * xprt_reconnect_delay - compute the wait before scheduling a connect
 960 * @xprt: transport instance
 961 *
 962 */
 963unsigned long xprt_reconnect_delay(const struct rpc_xprt *xprt)
 964{
 965	unsigned long start, now = jiffies;
 966
 967	start = xprt->stat.connect_start + xprt->reestablish_timeout;
 968	if (time_after(start, now))
 969		return start - now;
 970	return 0;
 971}
 972EXPORT_SYMBOL_GPL(xprt_reconnect_delay);
 973
 974/**
 975 * xprt_reconnect_backoff - compute the new re-establish timeout
 976 * @xprt: transport instance
 977 * @init_to: initial reestablish timeout
 978 *
 979 */
 980void xprt_reconnect_backoff(struct rpc_xprt *xprt, unsigned long init_to)
 981{
 982	xprt->reestablish_timeout <<= 1;
 983	if (xprt->reestablish_timeout > xprt->max_reconnect_timeout)
 984		xprt->reestablish_timeout = xprt->max_reconnect_timeout;
 985	if (xprt->reestablish_timeout < init_to)
 986		xprt->reestablish_timeout = init_to;
 987}
 988EXPORT_SYMBOL_GPL(xprt_reconnect_backoff);
 989
 990enum xprt_xid_rb_cmp {
 991	XID_RB_EQUAL,
 992	XID_RB_LEFT,
 993	XID_RB_RIGHT,
 994};
 995static enum xprt_xid_rb_cmp
 996xprt_xid_cmp(__be32 xid1, __be32 xid2)
 997{
 998	if (xid1 == xid2)
 999		return XID_RB_EQUAL;
1000	if ((__force u32)xid1 < (__force u32)xid2)
1001		return XID_RB_LEFT;
1002	return XID_RB_RIGHT;
1003}
1004
1005static struct rpc_rqst *
1006xprt_request_rb_find(struct rpc_xprt *xprt, __be32 xid)
1007{
1008	struct rb_node *n = xprt->recv_queue.rb_node;
1009	struct rpc_rqst *req;
1010
1011	while (n != NULL) {
1012		req = rb_entry(n, struct rpc_rqst, rq_recv);
1013		switch (xprt_xid_cmp(xid, req->rq_xid)) {
1014		case XID_RB_LEFT:
1015			n = n->rb_left;
1016			break;
1017		case XID_RB_RIGHT:
1018			n = n->rb_right;
1019			break;
1020		case XID_RB_EQUAL:
1021			return req;
1022		}
1023	}
1024	return NULL;
1025}
1026
1027static void
1028xprt_request_rb_insert(struct rpc_xprt *xprt, struct rpc_rqst *new)
1029{
1030	struct rb_node **p = &xprt->recv_queue.rb_node;
1031	struct rb_node *n = NULL;
1032	struct rpc_rqst *req;
1033
1034	while (*p != NULL) {
1035		n = *p;
1036		req = rb_entry(n, struct rpc_rqst, rq_recv);
1037		switch(xprt_xid_cmp(new->rq_xid, req->rq_xid)) {
1038		case XID_RB_LEFT:
1039			p = &n->rb_left;
1040			break;
1041		case XID_RB_RIGHT:
1042			p = &n->rb_right;
1043			break;
1044		case XID_RB_EQUAL:
1045			WARN_ON_ONCE(new != req);
1046			return;
1047		}
1048	}
1049	rb_link_node(&new->rq_recv, n, p);
1050	rb_insert_color(&new->rq_recv, &xprt->recv_queue);
1051}
1052
1053static void
1054xprt_request_rb_remove(struct rpc_xprt *xprt, struct rpc_rqst *req)
1055{
1056	rb_erase(&req->rq_recv, &xprt->recv_queue);
1057}
1058
1059/**
1060 * xprt_lookup_rqst - find an RPC request corresponding to an XID
1061 * @xprt: transport on which the original request was transmitted
1062 * @xid: RPC XID of incoming reply
1063 *
1064 * Caller holds xprt->queue_lock.
1065 */
1066struct rpc_rqst *xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid)
1067{
1068	struct rpc_rqst *entry;
1069
1070	entry = xprt_request_rb_find(xprt, xid);
1071	if (entry != NULL) {
1072		trace_xprt_lookup_rqst(xprt, xid, 0);
1073		entry->rq_rtt = ktime_sub(ktime_get(), entry->rq_xtime);
1074		return entry;
1075	}
1076
1077	dprintk("RPC:       xprt_lookup_rqst did not find xid %08x\n",
1078			ntohl(xid));
1079	trace_xprt_lookup_rqst(xprt, xid, -ENOENT);
1080	xprt->stat.bad_xids++;
1081	return NULL;
1082}
1083EXPORT_SYMBOL_GPL(xprt_lookup_rqst);
1084
1085static bool
1086xprt_is_pinned_rqst(struct rpc_rqst *req)
1087{
1088	return atomic_read(&req->rq_pin) != 0;
1089}
1090
1091/**
1092 * xprt_pin_rqst - Pin a request on the transport receive list
1093 * @req: Request to pin
1094 *
1095 * Caller must ensure this is atomic with the call to xprt_lookup_rqst()
1096 * so should be holding xprt->queue_lock.
1097 */
1098void xprt_pin_rqst(struct rpc_rqst *req)
1099{
1100	atomic_inc(&req->rq_pin);
1101}
1102EXPORT_SYMBOL_GPL(xprt_pin_rqst);
1103
1104/**
1105 * xprt_unpin_rqst - Unpin a request on the transport receive list
1106 * @req: Request to pin
1107 *
1108 * Caller should be holding xprt->queue_lock.
1109 */
1110void xprt_unpin_rqst(struct rpc_rqst *req)
1111{
1112	if (!test_bit(RPC_TASK_MSG_PIN_WAIT, &req->rq_task->tk_runstate)) {
1113		atomic_dec(&req->rq_pin);
1114		return;
1115	}
1116	if (atomic_dec_and_test(&req->rq_pin))
1117		wake_up_var(&req->rq_pin);
1118}
1119EXPORT_SYMBOL_GPL(xprt_unpin_rqst);
1120
1121static void xprt_wait_on_pinned_rqst(struct rpc_rqst *req)
1122{
1123	wait_var_event(&req->rq_pin, !xprt_is_pinned_rqst(req));
1124}
1125
1126static bool
1127xprt_request_data_received(struct rpc_task *task)
1128{
1129	return !test_bit(RPC_TASK_NEED_RECV, &task->tk_runstate) &&
1130		READ_ONCE(task->tk_rqstp->rq_reply_bytes_recvd) != 0;
1131}
1132
1133static bool
1134xprt_request_need_enqueue_receive(struct rpc_task *task, struct rpc_rqst *req)
1135{
1136	return !test_bit(RPC_TASK_NEED_RECV, &task->tk_runstate) &&
1137		READ_ONCE(task->tk_rqstp->rq_reply_bytes_recvd) == 0;
1138}
1139
1140/**
1141 * xprt_request_enqueue_receive - Add an request to the receive queue
1142 * @task: RPC task
1143 *
1144 */
1145int
1146xprt_request_enqueue_receive(struct rpc_task *task)
1147{
1148	struct rpc_rqst *req = task->tk_rqstp;
1149	struct rpc_xprt *xprt = req->rq_xprt;
1150	int ret;
1151
1152	if (!xprt_request_need_enqueue_receive(task, req))
1153		return 0;
1154
1155	ret = xprt_request_prepare(task->tk_rqstp, &req->rq_rcv_buf);
1156	if (ret)
1157		return ret;
1158	spin_lock(&xprt->queue_lock);
1159
1160	/* Update the softirq receive buffer */
1161	memcpy(&req->rq_private_buf, &req->rq_rcv_buf,
1162			sizeof(req->rq_private_buf));
1163
1164	/* Add request to the receive list */
1165	xprt_request_rb_insert(xprt, req);
1166	set_bit(RPC_TASK_NEED_RECV, &task->tk_runstate);
1167	spin_unlock(&xprt->queue_lock);
1168
1169	/* Turn off autodisconnect */
1170	del_timer_sync(&xprt->timer);
1171	return 0;
1172}
1173
1174/**
1175 * xprt_request_dequeue_receive_locked - Remove a request from the receive queue
1176 * @task: RPC task
1177 *
1178 * Caller must hold xprt->queue_lock.
1179 */
1180static void
1181xprt_request_dequeue_receive_locked(struct rpc_task *task)
1182{
1183	struct rpc_rqst *req = task->tk_rqstp;
1184
1185	if (test_and_clear_bit(RPC_TASK_NEED_RECV, &task->tk_runstate))
1186		xprt_request_rb_remove(req->rq_xprt, req);
1187}
1188
1189/**
1190 * xprt_update_rtt - Update RPC RTT statistics
1191 * @task: RPC request that recently completed
1192 *
1193 * Caller holds xprt->queue_lock.
1194 */
1195void xprt_update_rtt(struct rpc_task *task)
1196{
1197	struct rpc_rqst *req = task->tk_rqstp;
1198	struct rpc_rtt *rtt = task->tk_client->cl_rtt;
1199	unsigned int timer = task->tk_msg.rpc_proc->p_timer;
1200	long m = usecs_to_jiffies(ktime_to_us(req->rq_rtt));
1201
1202	if (timer) {
1203		if (req->rq_ntrans == 1)
1204			rpc_update_rtt(rtt, timer, m);
1205		rpc_set_timeo(rtt, timer, req->rq_ntrans - 1);
1206	}
1207}
1208EXPORT_SYMBOL_GPL(xprt_update_rtt);
1209
1210/**
1211 * xprt_complete_rqst - called when reply processing is complete
1212 * @task: RPC request that recently completed
1213 * @copied: actual number of bytes received from the transport
1214 *
1215 * Caller holds xprt->queue_lock.
1216 */
1217void xprt_complete_rqst(struct rpc_task *task, int copied)
1218{
1219	struct rpc_rqst *req = task->tk_rqstp;
1220	struct rpc_xprt *xprt = req->rq_xprt;
1221
1222	xprt->stat.recvs++;
1223
1224	xdr_free_bvec(&req->rq_rcv_buf);
1225	req->rq_private_buf.bvec = NULL;
1226	req->rq_private_buf.len = copied;
1227	/* Ensure all writes are done before we update */
1228	/* req->rq_reply_bytes_recvd */
1229	smp_wmb();
1230	req->rq_reply_bytes_recvd = copied;
1231	xprt_request_dequeue_receive_locked(task);
1232	rpc_wake_up_queued_task(&xprt->pending, task);
1233}
1234EXPORT_SYMBOL_GPL(xprt_complete_rqst);
1235
1236static void xprt_timer(struct rpc_task *task)
1237{
1238	struct rpc_rqst *req = task->tk_rqstp;
1239	struct rpc_xprt *xprt = req->rq_xprt;
1240
1241	if (task->tk_status != -ETIMEDOUT)
1242		return;
1243
1244	trace_xprt_timer(xprt, req->rq_xid, task->tk_status);
1245	if (!req->rq_reply_bytes_recvd) {
1246		if (xprt->ops->timer)
1247			xprt->ops->timer(xprt, task);
1248	} else
1249		task->tk_status = 0;
1250}
1251
1252/**
1253 * xprt_wait_for_reply_request_def - wait for reply
1254 * @task: pointer to rpc_task
1255 *
1256 * Set a request's retransmit timeout based on the transport's
1257 * default timeout parameters.  Used by transports that don't adjust
1258 * the retransmit timeout based on round-trip time estimation,
1259 * and put the task to sleep on the pending queue.
1260 */
1261void xprt_wait_for_reply_request_def(struct rpc_task *task)
1262{
1263	struct rpc_rqst *req = task->tk_rqstp;
1264
1265	rpc_sleep_on_timeout(&req->rq_xprt->pending, task, xprt_timer,
1266			xprt_request_timeout(req));
1267}
1268EXPORT_SYMBOL_GPL(xprt_wait_for_reply_request_def);
1269
1270/**
1271 * xprt_wait_for_reply_request_rtt - wait for reply using RTT estimator
1272 * @task: pointer to rpc_task
1273 *
1274 * Set a request's retransmit timeout using the RTT estimator,
1275 * and put the task to sleep on the pending queue.
1276 */
1277void xprt_wait_for_reply_request_rtt(struct rpc_task *task)
1278{
1279	int timer = task->tk_msg.rpc_proc->p_timer;
1280	struct rpc_clnt *clnt = task->tk_client;
1281	struct rpc_rtt *rtt = clnt->cl_rtt;
1282	struct rpc_rqst *req = task->tk_rqstp;
1283	unsigned long max_timeout = clnt->cl_timeout->to_maxval;
1284	unsigned long timeout;
1285
1286	timeout = rpc_calc_rto(rtt, timer);
1287	timeout <<= rpc_ntimeo(rtt, timer) + req->rq_retries;
1288	if (timeout > max_timeout || timeout == 0)
1289		timeout = max_timeout;
1290	rpc_sleep_on_timeout(&req->rq_xprt->pending, task, xprt_timer,
1291			jiffies + timeout);
1292}
1293EXPORT_SYMBOL_GPL(xprt_wait_for_reply_request_rtt);
1294
1295/**
1296 * xprt_request_wait_receive - wait for the reply to an RPC request
1297 * @task: RPC task about to send a request
1298 *
1299 */
1300void xprt_request_wait_receive(struct rpc_task *task)
1301{
1302	struct rpc_rqst *req = task->tk_rqstp;
1303	struct rpc_xprt *xprt = req->rq_xprt;
1304
1305	if (!test_bit(RPC_TASK_NEED_RECV, &task->tk_runstate))
1306		return;
1307	/*
1308	 * Sleep on the pending queue if we're expecting a reply.
1309	 * The spinlock ensures atomicity between the test of
1310	 * req->rq_reply_bytes_recvd, and the call to rpc_sleep_on().
1311	 */
1312	spin_lock(&xprt->queue_lock);
1313	if (test_bit(RPC_TASK_NEED_RECV, &task->tk_runstate)) {
1314		xprt->ops->wait_for_reply_request(task);
1315		/*
1316		 * Send an extra queue wakeup call if the
1317		 * connection was dropped in case the call to
1318		 * rpc_sleep_on() raced.
1319		 */
1320		if (xprt_request_retransmit_after_disconnect(task))
1321			rpc_wake_up_queued_task_set_status(&xprt->pending,
1322					task, -ENOTCONN);
1323	}
1324	spin_unlock(&xprt->queue_lock);
1325}
1326
1327static bool
1328xprt_request_need_enqueue_transmit(struct rpc_task *task, struct rpc_rqst *req)
1329{
1330	return !test_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate);
1331}
1332
1333/**
1334 * xprt_request_enqueue_transmit - queue a task for transmission
1335 * @task: pointer to rpc_task
1336 *
1337 * Add a task to the transmission queue.
1338 */
1339void
1340xprt_request_enqueue_transmit(struct rpc_task *task)
1341{
1342	struct rpc_rqst *pos, *req = task->tk_rqstp;
1343	struct rpc_xprt *xprt = req->rq_xprt;
1344	int ret;
1345
1346	if (xprt_request_need_enqueue_transmit(task, req)) {
1347		ret = xprt_request_prepare(task->tk_rqstp, &req->rq_snd_buf);
1348		if (ret) {
1349			task->tk_status = ret;
1350			return;
1351		}
1352		req->rq_bytes_sent = 0;
1353		spin_lock(&xprt->queue_lock);
1354		/*
1355		 * Requests that carry congestion control credits are added
1356		 * to the head of the list to avoid starvation issues.
1357		 */
1358		if (req->rq_cong) {
1359			xprt_clear_congestion_window_wait(xprt);
1360			list_for_each_entry(pos, &xprt->xmit_queue, rq_xmit) {
1361				if (pos->rq_cong)
1362					continue;
1363				/* Note: req is added _before_ pos */
1364				list_add_tail(&req->rq_xmit, &pos->rq_xmit);
1365				INIT_LIST_HEAD(&req->rq_xmit2);
1366				goto out;
1367			}
1368		} else if (!req->rq_seqno) {
1369			list_for_each_entry(pos, &xprt->xmit_queue, rq_xmit) {
1370				if (pos->rq_task->tk_owner != task->tk_owner)
1371					continue;
1372				list_add_tail(&req->rq_xmit2, &pos->rq_xmit2);
1373				INIT_LIST_HEAD(&req->rq_xmit);
1374				goto out;
1375			}
1376		}
1377		list_add_tail(&req->rq_xmit, &xprt->xmit_queue);
1378		INIT_LIST_HEAD(&req->rq_xmit2);
1379out:
1380		atomic_long_inc(&xprt->xmit_queuelen);
1381		set_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate);
1382		spin_unlock(&xprt->queue_lock);
1383	}
1384}
1385
1386/**
1387 * xprt_request_dequeue_transmit_locked - remove a task from the transmission queue
1388 * @task: pointer to rpc_task
1389 *
1390 * Remove a task from the transmission queue
1391 * Caller must hold xprt->queue_lock
1392 */
1393static void
1394xprt_request_dequeue_transmit_locked(struct rpc_task *task)
1395{
1396	struct rpc_rqst *req = task->tk_rqstp;
1397
1398	if (!test_and_clear_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate))
1399		return;
1400	if (!list_empty(&req->rq_xmit)) {
1401		list_del(&req->rq_xmit);
1402		if (!list_empty(&req->rq_xmit2)) {
1403			struct rpc_rqst *next = list_first_entry(&req->rq_xmit2,
1404					struct rpc_rqst, rq_xmit2);
1405			list_del(&req->rq_xmit2);
1406			list_add_tail(&next->rq_xmit, &next->rq_xprt->xmit_queue);
1407		}
1408	} else
1409		list_del(&req->rq_xmit2);
1410	atomic_long_dec(&req->rq_xprt->xmit_queuelen);
1411	xdr_free_bvec(&req->rq_snd_buf);
1412}
1413
1414/**
1415 * xprt_request_dequeue_transmit - remove a task from the transmission queue
1416 * @task: pointer to rpc_task
1417 *
1418 * Remove a task from the transmission queue
1419 */
1420static void
1421xprt_request_dequeue_transmit(struct rpc_task *task)
1422{
1423	struct rpc_rqst *req = task->tk_rqstp;
1424	struct rpc_xprt *xprt = req->rq_xprt;
1425
1426	spin_lock(&xprt->queue_lock);
1427	xprt_request_dequeue_transmit_locked(task);
1428	spin_unlock(&xprt->queue_lock);
1429}
1430
1431/**
1432 * xprt_request_dequeue_xprt - remove a task from the transmit+receive queue
1433 * @task: pointer to rpc_task
1434 *
1435 * Remove a task from the transmit and receive queues, and ensure that
1436 * it is not pinned by the receive work item.
1437 */
1438void
1439xprt_request_dequeue_xprt(struct rpc_task *task)
1440{
1441	struct rpc_rqst	*req = task->tk_rqstp;
1442	struct rpc_xprt *xprt = req->rq_xprt;
1443
1444	if (test_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate) ||
1445	    test_bit(RPC_TASK_NEED_RECV, &task->tk_runstate) ||
1446	    xprt_is_pinned_rqst(req)) {
1447		spin_lock(&xprt->queue_lock);
1448		while (xprt_is_pinned_rqst(req)) {
1449			set_bit(RPC_TASK_MSG_PIN_WAIT, &task->tk_runstate);
1450			spin_unlock(&xprt->queue_lock);
1451			xprt_wait_on_pinned_rqst(req);
1452			spin_lock(&xprt->queue_lock);
1453			clear_bit(RPC_TASK_MSG_PIN_WAIT, &task->tk_runstate);
1454		}
1455		xprt_request_dequeue_transmit_locked(task);
1456		xprt_request_dequeue_receive_locked(task);
1457		spin_unlock(&xprt->queue_lock);
1458		xdr_free_bvec(&req->rq_rcv_buf);
1459	}
1460}
1461
1462/**
1463 * xprt_request_prepare - prepare an encoded request for transport
1464 * @req: pointer to rpc_rqst
1465 * @buf: pointer to send/rcv xdr_buf
1466 *
1467 * Calls into the transport layer to do whatever is needed to prepare
1468 * the request for transmission or receive.
1469 * Returns error, or zero.
1470 */
1471static int
1472xprt_request_prepare(struct rpc_rqst *req, struct xdr_buf *buf)
1473{
1474	struct rpc_xprt *xprt = req->rq_xprt;
1475
1476	if (xprt->ops->prepare_request)
1477		return xprt->ops->prepare_request(req, buf);
1478	return 0;
1479}
1480
1481/**
1482 * xprt_request_need_retransmit - Test if a task needs retransmission
1483 * @task: pointer to rpc_task
1484 *
1485 * Test for whether a connection breakage requires the task to retransmit
1486 */
1487bool
1488xprt_request_need_retransmit(struct rpc_task *task)
1489{
1490	return xprt_request_retransmit_after_disconnect(task);
1491}
1492
1493/**
1494 * xprt_prepare_transmit - reserve the transport before sending a request
1495 * @task: RPC task about to send a request
1496 *
1497 */
1498bool xprt_prepare_transmit(struct rpc_task *task)
1499{
1500	struct rpc_rqst	*req = task->tk_rqstp;
1501	struct rpc_xprt	*xprt = req->rq_xprt;
1502
1503	if (!xprt_lock_write(xprt, task)) {
1504		/* Race breaker: someone may have transmitted us */
1505		if (!test_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate))
1506			rpc_wake_up_queued_task_set_status(&xprt->sending,
1507					task, 0);
1508		return false;
1509
1510	}
1511	if (atomic_read(&xprt->swapper))
1512		/* This will be clear in __rpc_execute */
1513		current->flags |= PF_MEMALLOC;
1514	return true;
1515}
1516
1517void xprt_end_transmit(struct rpc_task *task)
1518{
1519	struct rpc_xprt	*xprt = task->tk_rqstp->rq_xprt;
1520
1521	xprt_inject_disconnect(xprt);
1522	xprt_release_write(xprt, task);
1523}
1524
1525/**
1526 * xprt_request_transmit - send an RPC request on a transport
1527 * @req: pointer to request to transmit
1528 * @snd_task: RPC task that owns the transport lock
1529 *
1530 * This performs the transmission of a single request.
1531 * Note that if the request is not the same as snd_task, then it
1532 * does need to be pinned.
1533 * Returns '0' on success.
1534 */
1535static int
1536xprt_request_transmit(struct rpc_rqst *req, struct rpc_task *snd_task)
1537{
1538	struct rpc_xprt *xprt = req->rq_xprt;
1539	struct rpc_task *task = req->rq_task;
1540	unsigned int connect_cookie;
1541	int is_retrans = RPC_WAS_SENT(task);
1542	int status;
1543
1544	if (!req->rq_bytes_sent) {
1545		if (xprt_request_data_received(task)) {
1546			status = 0;
1547			goto out_dequeue;
1548		}
1549		/* Verify that our message lies in the RPCSEC_GSS window */
1550		if (rpcauth_xmit_need_reencode(task)) {
1551			status = -EBADMSG;
1552			goto out_dequeue;
1553		}
1554		if (RPC_SIGNALLED(task)) {
1555			status = -ERESTARTSYS;
1556			goto out_dequeue;
1557		}
1558	}
1559
1560	/*
1561	 * Update req->rq_ntrans before transmitting to avoid races with
1562	 * xprt_update_rtt(), which needs to know that it is recording a
1563	 * reply to the first transmission.
1564	 */
1565	req->rq_ntrans++;
1566
1567	trace_rpc_xdr_sendto(task, &req->rq_snd_buf);
1568	connect_cookie = xprt->connect_cookie;
1569	status = xprt->ops->send_request(req);
1570	if (status != 0) {
1571		req->rq_ntrans--;
1572		trace_xprt_transmit(req, status);
1573		return status;
1574	}
1575
1576	if (is_retrans) {
1577		task->tk_client->cl_stats->rpcretrans++;
1578		trace_xprt_retransmit(req);
1579	}
1580
1581	xprt_inject_disconnect(xprt);
1582
1583	task->tk_flags |= RPC_TASK_SENT;
1584	spin_lock(&xprt->transport_lock);
1585
1586	xprt->stat.sends++;
1587	xprt->stat.req_u += xprt->stat.sends - xprt->stat.recvs;
1588	xprt->stat.bklog_u += xprt->backlog.qlen;
1589	xprt->stat.sending_u += xprt->sending.qlen;
1590	xprt->stat.pending_u += xprt->pending.qlen;
1591	spin_unlock(&xprt->transport_lock);
1592
1593	req->rq_connect_cookie = connect_cookie;
1594out_dequeue:
1595	trace_xprt_transmit(req, status);
1596	xprt_request_dequeue_transmit(task);
1597	rpc_wake_up_queued_task_set_status(&xprt->sending, task, status);
1598	return status;
1599}
1600
1601/**
1602 * xprt_transmit - send an RPC request on a transport
1603 * @task: controlling RPC task
1604 *
1605 * Attempts to drain the transmit queue. On exit, either the transport
1606 * signalled an error that needs to be handled before transmission can
1607 * resume, or @task finished transmitting, and detected that it already
1608 * received a reply.
1609 */
1610void
1611xprt_transmit(struct rpc_task *task)
1612{
1613	struct rpc_rqst *next, *req = task->tk_rqstp;
1614	struct rpc_xprt	*xprt = req->rq_xprt;
1615	int status;
1616
1617	spin_lock(&xprt->queue_lock);
1618	for (;;) {
1619		next = list_first_entry_or_null(&xprt->xmit_queue,
1620						struct rpc_rqst, rq_xmit);
1621		if (!next)
1622			break;
1623		xprt_pin_rqst(next);
1624		spin_unlock(&xprt->queue_lock);
1625		status = xprt_request_transmit(next, task);
1626		if (status == -EBADMSG && next != req)
1627			status = 0;
1628		spin_lock(&xprt->queue_lock);
1629		xprt_unpin_rqst(next);
1630		if (status < 0) {
1631			if (test_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate))
1632				task->tk_status = status;
1633			break;
1634		}
1635		/* Was @task transmitted, and has it received a reply? */
1636		if (xprt_request_data_received(task) &&
1637		    !test_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate))
1638			break;
1639		cond_resched_lock(&xprt->queue_lock);
1640	}
1641	spin_unlock(&xprt->queue_lock);
1642}
1643
1644static void xprt_complete_request_init(struct rpc_task *task)
1645{
1646	if (task->tk_rqstp)
1647		xprt_request_init(task);
1648}
1649
1650void xprt_add_backlog(struct rpc_xprt *xprt, struct rpc_task *task)
1651{
1652	set_bit(XPRT_CONGESTED, &xprt->state);
1653	rpc_sleep_on(&xprt->backlog, task, xprt_complete_request_init);
1654}
1655EXPORT_SYMBOL_GPL(xprt_add_backlog);
1656
1657static bool __xprt_set_rq(struct rpc_task *task, void *data)
1658{
1659	struct rpc_rqst *req = data;
1660
1661	if (task->tk_rqstp == NULL) {
1662		memset(req, 0, sizeof(*req));	/* mark unused */
1663		task->tk_rqstp = req;
1664		return true;
1665	}
1666	return false;
1667}
1668
1669bool xprt_wake_up_backlog(struct rpc_xprt *xprt, struct rpc_rqst *req)
1670{
1671	if (rpc_wake_up_first(&xprt->backlog, __xprt_set_rq, req) == NULL) {
1672		clear_bit(XPRT_CONGESTED, &xprt->state);
1673		return false;
1674	}
1675	return true;
1676}
1677EXPORT_SYMBOL_GPL(xprt_wake_up_backlog);
1678
1679static bool xprt_throttle_congested(struct rpc_xprt *xprt, struct rpc_task *task)
1680{
1681	bool ret = false;
1682
1683	if (!test_bit(XPRT_CONGESTED, &xprt->state))
1684		goto out;
1685	spin_lock(&xprt->reserve_lock);
1686	if (test_bit(XPRT_CONGESTED, &xprt->state)) {
1687		xprt_add_backlog(xprt, task);
1688		ret = true;
1689	}
1690	spin_unlock(&xprt->reserve_lock);
1691out:
1692	return ret;
1693}
1694
1695static struct rpc_rqst *xprt_dynamic_alloc_slot(struct rpc_xprt *xprt)
1696{
1697	struct rpc_rqst *req = ERR_PTR(-EAGAIN);
1698
1699	if (xprt->num_reqs >= xprt->max_reqs)
1700		goto out;
1701	++xprt->num_reqs;
1702	spin_unlock(&xprt->reserve_lock);
1703	req = kzalloc(sizeof(*req), rpc_task_gfp_mask());
1704	spin_lock(&xprt->reserve_lock);
1705	if (req != NULL)
1706		goto out;
1707	--xprt->num_reqs;
1708	req = ERR_PTR(-ENOMEM);
1709out:
1710	return req;
1711}
1712
1713static bool xprt_dynamic_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *req)
1714{
1715	if (xprt->num_reqs > xprt->min_reqs) {
1716		--xprt->num_reqs;
1717		kfree(req);
1718		return true;
1719	}
1720	return false;
1721}
1722
1723void xprt_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task)
1724{
1725	struct rpc_rqst *req;
1726
1727	spin_lock(&xprt->reserve_lock);
1728	if (!list_empty(&xprt->free)) {
1729		req = list_entry(xprt->free.next, struct rpc_rqst, rq_list);
1730		list_del(&req->rq_list);
1731		goto out_init_req;
1732	}
1733	req = xprt_dynamic_alloc_slot(xprt);
1734	if (!IS_ERR(req))
1735		goto out_init_req;
1736	switch (PTR_ERR(req)) {
1737	case -ENOMEM:
1738		dprintk("RPC:       dynamic allocation of request slot "
1739				"failed! Retrying\n");
1740		task->tk_status = -ENOMEM;
1741		break;
1742	case -EAGAIN:
1743		xprt_add_backlog(xprt, task);
1744		dprintk("RPC:       waiting for request slot\n");
1745		fallthrough;
1746	default:
1747		task->tk_status = -EAGAIN;
1748	}
1749	spin_unlock(&xprt->reserve_lock);
1750	return;
1751out_init_req:
1752	xprt->stat.max_slots = max_t(unsigned int, xprt->stat.max_slots,
1753				     xprt->num_reqs);
1754	spin_unlock(&xprt->reserve_lock);
1755
1756	task->tk_status = 0;
1757	task->tk_rqstp = req;
1758}
1759EXPORT_SYMBOL_GPL(xprt_alloc_slot);
1760
1761void xprt_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *req)
1762{
1763	spin_lock(&xprt->reserve_lock);
1764	if (!xprt_wake_up_backlog(xprt, req) &&
1765	    !xprt_dynamic_free_slot(xprt, req)) {
1766		memset(req, 0, sizeof(*req));	/* mark unused */
1767		list_add(&req->rq_list, &xprt->free);
1768	}
1769	spin_unlock(&xprt->reserve_lock);
1770}
1771EXPORT_SYMBOL_GPL(xprt_free_slot);
1772
1773static void xprt_free_all_slots(struct rpc_xprt *xprt)
1774{
1775	struct rpc_rqst *req;
1776	while (!list_empty(&xprt->free)) {
1777		req = list_first_entry(&xprt->free, struct rpc_rqst, rq_list);
1778		list_del(&req->rq_list);
1779		kfree(req);
1780	}
1781}
1782
1783static DEFINE_IDA(rpc_xprt_ids);
1784
1785void xprt_cleanup_ids(void)
1786{
1787	ida_destroy(&rpc_xprt_ids);
1788}
1789
1790static int xprt_alloc_id(struct rpc_xprt *xprt)
1791{
1792	int id;
1793
1794	id = ida_alloc(&rpc_xprt_ids, GFP_KERNEL);
1795	if (id < 0)
1796		return id;
1797
1798	xprt->id = id;
1799	return 0;
1800}
1801
1802static void xprt_free_id(struct rpc_xprt *xprt)
1803{
1804	ida_free(&rpc_xprt_ids, xprt->id);
1805}
1806
1807struct rpc_xprt *xprt_alloc(struct net *net, size_t size,
1808		unsigned int num_prealloc,
1809		unsigned int max_alloc)
1810{
1811	struct rpc_xprt *xprt;
1812	struct rpc_rqst *req;
1813	int i;
1814
1815	xprt = kzalloc(size, GFP_KERNEL);
1816	if (xprt == NULL)
1817		goto out;
1818
1819	xprt_alloc_id(xprt);
1820	xprt_init(xprt, net);
1821
1822	for (i = 0; i < num_prealloc; i++) {
1823		req = kzalloc(sizeof(struct rpc_rqst), GFP_KERNEL);
1824		if (!req)
1825			goto out_free;
1826		list_add(&req->rq_list, &xprt->free);
1827	}
1828	xprt->max_reqs = max_t(unsigned int, max_alloc, num_prealloc);
1829	xprt->min_reqs = num_prealloc;
1830	xprt->num_reqs = num_prealloc;
1831
1832	return xprt;
1833
1834out_free:
1835	xprt_free(xprt);
1836out:
1837	return NULL;
1838}
1839EXPORT_SYMBOL_GPL(xprt_alloc);
1840
1841void xprt_free(struct rpc_xprt *xprt)
1842{
1843	put_net_track(xprt->xprt_net, &xprt->ns_tracker);
1844	xprt_free_all_slots(xprt);
1845	xprt_free_id(xprt);
1846	rpc_sysfs_xprt_destroy(xprt);
1847	kfree_rcu(xprt, rcu);
1848}
1849EXPORT_SYMBOL_GPL(xprt_free);
1850
1851static void
1852xprt_init_connect_cookie(struct rpc_rqst *req, struct rpc_xprt *xprt)
1853{
1854	req->rq_connect_cookie = xprt_connect_cookie(xprt) - 1;
1855}
1856
1857static __be32
1858xprt_alloc_xid(struct rpc_xprt *xprt)
1859{
1860	__be32 xid;
1861
1862	spin_lock(&xprt->reserve_lock);
1863	xid = (__force __be32)xprt->xid++;
1864	spin_unlock(&xprt->reserve_lock);
1865	return xid;
1866}
1867
1868static void
1869xprt_init_xid(struct rpc_xprt *xprt)
1870{
1871	xprt->xid = get_random_u32();
1872}
1873
1874static void
1875xprt_request_init(struct rpc_task *task)
1876{
1877	struct rpc_xprt *xprt = task->tk_xprt;
1878	struct rpc_rqst	*req = task->tk_rqstp;
1879
1880	req->rq_task	= task;
1881	req->rq_xprt    = xprt;
1882	req->rq_buffer  = NULL;
1883	req->rq_xid	= xprt_alloc_xid(xprt);
1884	xprt_init_connect_cookie(req, xprt);
1885	req->rq_snd_buf.len = 0;
1886	req->rq_snd_buf.buflen = 0;
1887	req->rq_rcv_buf.len = 0;
1888	req->rq_rcv_buf.buflen = 0;
1889	req->rq_snd_buf.bvec = NULL;
1890	req->rq_rcv_buf.bvec = NULL;
1891	req->rq_release_snd_buf = NULL;
1892	xprt_init_majortimeo(task, req, task->tk_client->cl_timeout);
1893
1894	trace_xprt_reserve(req);
1895}
1896
1897static void
1898xprt_do_reserve(struct rpc_xprt *xprt, struct rpc_task *task)
1899{
1900	xprt->ops->alloc_slot(xprt, task);
1901	if (task->tk_rqstp != NULL)
1902		xprt_request_init(task);
1903}
1904
1905/**
1906 * xprt_reserve - allocate an RPC request slot
1907 * @task: RPC task requesting a slot allocation
1908 *
1909 * If the transport is marked as being congested, or if no more
1910 * slots are available, place the task on the transport's
1911 * backlog queue.
1912 */
1913void xprt_reserve(struct rpc_task *task)
1914{
1915	struct rpc_xprt *xprt = task->tk_xprt;
1916
1917	task->tk_status = 0;
1918	if (task->tk_rqstp != NULL)
1919		return;
1920
1921	task->tk_status = -EAGAIN;
1922	if (!xprt_throttle_congested(xprt, task))
1923		xprt_do_reserve(xprt, task);
1924}
1925
1926/**
1927 * xprt_retry_reserve - allocate an RPC request slot
1928 * @task: RPC task requesting a slot allocation
1929 *
1930 * If no more slots are available, place the task on the transport's
1931 * backlog queue.
1932 * Note that the only difference with xprt_reserve is that we now
1933 * ignore the value of the XPRT_CONGESTED flag.
1934 */
1935void xprt_retry_reserve(struct rpc_task *task)
1936{
1937	struct rpc_xprt *xprt = task->tk_xprt;
1938
1939	task->tk_status = 0;
1940	if (task->tk_rqstp != NULL)
1941		return;
1942
1943	task->tk_status = -EAGAIN;
1944	xprt_do_reserve(xprt, task);
1945}
1946
1947/**
1948 * xprt_release - release an RPC request slot
1949 * @task: task which is finished with the slot
1950 *
1951 */
1952void xprt_release(struct rpc_task *task)
1953{
1954	struct rpc_xprt	*xprt;
1955	struct rpc_rqst	*req = task->tk_rqstp;
1956
1957	if (req == NULL) {
1958		if (task->tk_client) {
1959			xprt = task->tk_xprt;
1960			xprt_release_write(xprt, task);
1961		}
1962		return;
1963	}
1964
1965	xprt = req->rq_xprt;
1966	xprt_request_dequeue_xprt(task);
1967	spin_lock(&xprt->transport_lock);
1968	xprt->ops->release_xprt(xprt, task);
1969	if (xprt->ops->release_request)
1970		xprt->ops->release_request(task);
1971	xprt_schedule_autodisconnect(xprt);
1972	spin_unlock(&xprt->transport_lock);
1973	if (req->rq_buffer)
1974		xprt->ops->buf_free(task);
1975	if (req->rq_cred != NULL)
1976		put_rpccred(req->rq_cred);
1977	if (req->rq_release_snd_buf)
1978		req->rq_release_snd_buf(req);
1979
1980	task->tk_rqstp = NULL;
1981	if (likely(!bc_prealloc(req)))
1982		xprt->ops->free_slot(xprt, req);
1983	else
1984		xprt_free_bc_request(req);
1985}
1986
1987#ifdef CONFIG_SUNRPC_BACKCHANNEL
1988void
1989xprt_init_bc_request(struct rpc_rqst *req, struct rpc_task *task,
1990		const struct rpc_timeout *to)
1991{
1992	struct xdr_buf *xbufp = &req->rq_snd_buf;
1993
1994	task->tk_rqstp = req;
1995	req->rq_task = task;
1996	xprt_init_connect_cookie(req, req->rq_xprt);
1997	/*
1998	 * Set up the xdr_buf length.
1999	 * This also indicates that the buffer is XDR encoded already.
2000	 */
2001	xbufp->len = xbufp->head[0].iov_len + xbufp->page_len +
2002		xbufp->tail[0].iov_len;
2003	/*
2004	 * Backchannel Replies are sent with !RPC_TASK_SOFT and
2005	 * RPC_TASK_NO_RETRANS_TIMEOUT. The major timeout setting
2006	 * affects only how long each Reply waits to be sent when
2007	 * a transport connection cannot be established.
2008	 */
2009	xprt_init_majortimeo(task, req, to);
2010}
2011#endif
2012
2013static void xprt_init(struct rpc_xprt *xprt, struct net *net)
2014{
2015	kref_init(&xprt->kref);
2016
2017	spin_lock_init(&xprt->transport_lock);
2018	spin_lock_init(&xprt->reserve_lock);
2019	spin_lock_init(&xprt->queue_lock);
2020
2021	INIT_LIST_HEAD(&xprt->free);
2022	xprt->recv_queue = RB_ROOT;
2023	INIT_LIST_HEAD(&xprt->xmit_queue);
2024#if defined(CONFIG_SUNRPC_BACKCHANNEL)
2025	spin_lock_init(&xprt->bc_pa_lock);
2026	INIT_LIST_HEAD(&xprt->bc_pa_list);
2027#endif /* CONFIG_SUNRPC_BACKCHANNEL */
2028	INIT_LIST_HEAD(&xprt->xprt_switch);
2029
2030	xprt->last_used = jiffies;
2031	xprt->cwnd = RPC_INITCWND;
2032	xprt->bind_index = 0;
2033
2034	rpc_init_wait_queue(&xprt->binding, "xprt_binding");
2035	rpc_init_wait_queue(&xprt->pending, "xprt_pending");
2036	rpc_init_wait_queue(&xprt->sending, "xprt_sending");
2037	rpc_init_priority_wait_queue(&xprt->backlog, "xprt_backlog");
2038
2039	xprt_init_xid(xprt);
2040
2041	xprt->xprt_net = get_net_track(net, &xprt->ns_tracker, GFP_KERNEL);
2042}
2043
2044/**
2045 * xprt_create_transport - create an RPC transport
2046 * @args: rpc transport creation arguments
2047 *
2048 */
2049struct rpc_xprt *xprt_create_transport(struct xprt_create *args)
2050{
2051	struct rpc_xprt	*xprt;
2052	const struct xprt_class *t;
2053
2054	t = xprt_class_find_by_ident(args->ident);
2055	if (!t) {
2056		dprintk("RPC: transport (%d) not supported\n", args->ident);
2057		return ERR_PTR(-EIO);
2058	}
2059
2060	xprt = t->setup(args);
2061	xprt_class_release(t);
2062
2063	if (IS_ERR(xprt))
2064		goto out;
2065	if (args->flags & XPRT_CREATE_NO_IDLE_TIMEOUT)
2066		xprt->idle_timeout = 0;
2067	INIT_WORK(&xprt->task_cleanup, xprt_autoclose);
2068	if (xprt_has_timer(xprt))
2069		timer_setup(&xprt->timer, xprt_init_autodisconnect, 0);
2070	else
2071		timer_setup(&xprt->timer, NULL, 0);
2072
2073	if (strlen(args->servername) > RPC_MAXNETNAMELEN) {
2074		xprt_destroy(xprt);
2075		return ERR_PTR(-EINVAL);
2076	}
2077	xprt->servername = kstrdup(args->servername, GFP_KERNEL);
2078	if (xprt->servername == NULL) {
2079		xprt_destroy(xprt);
2080		return ERR_PTR(-ENOMEM);
2081	}
2082
2083	rpc_xprt_debugfs_register(xprt);
2084
2085	trace_xprt_create(xprt);
2086out:
2087	return xprt;
2088}
2089
2090static void xprt_destroy_cb(struct work_struct *work)
2091{
2092	struct rpc_xprt *xprt =
2093		container_of(work, struct rpc_xprt, task_cleanup);
2094
2095	trace_xprt_destroy(xprt);
2096
2097	rpc_xprt_debugfs_unregister(xprt);
2098	rpc_destroy_wait_queue(&xprt->binding);
2099	rpc_destroy_wait_queue(&xprt->pending);
2100	rpc_destroy_wait_queue(&xprt->sending);
2101	rpc_destroy_wait_queue(&xprt->backlog);
2102	kfree(xprt->servername);
2103	/*
2104	 * Destroy any existing back channel
2105	 */
2106	xprt_destroy_backchannel(xprt, UINT_MAX);
2107
2108	/*
2109	 * Tear down transport state and free the rpc_xprt
2110	 */
2111	xprt->ops->destroy(xprt);
2112}
2113
2114/**
2115 * xprt_destroy - destroy an RPC transport, killing off all requests.
2116 * @xprt: transport to destroy
2117 *
2118 */
2119static void xprt_destroy(struct rpc_xprt *xprt)
2120{
2121	/*
2122	 * Exclude transport connect/disconnect handlers and autoclose
2123	 */
2124	wait_on_bit_lock(&xprt->state, XPRT_LOCKED, TASK_UNINTERRUPTIBLE);
2125
2126	/*
2127	 * xprt_schedule_autodisconnect() can run after XPRT_LOCKED
2128	 * is cleared.  We use ->transport_lock to ensure the mod_timer()
2129	 * can only run *before* del_time_sync(), never after.
2130	 */
2131	spin_lock(&xprt->transport_lock);
2132	del_timer_sync(&xprt->timer);
2133	spin_unlock(&xprt->transport_lock);
2134
2135	/*
2136	 * Destroy sockets etc from the system workqueue so they can
2137	 * safely flush receive work running on rpciod.
2138	 */
2139	INIT_WORK(&xprt->task_cleanup, xprt_destroy_cb);
2140	schedule_work(&xprt->task_cleanup);
2141}
2142
2143static void xprt_destroy_kref(struct kref *kref)
2144{
2145	xprt_destroy(container_of(kref, struct rpc_xprt, kref));
2146}
2147
2148/**
2149 * xprt_get - return a reference to an RPC transport.
2150 * @xprt: pointer to the transport
2151 *
2152 */
2153struct rpc_xprt *xprt_get(struct rpc_xprt *xprt)
2154{
2155	if (xprt != NULL && kref_get_unless_zero(&xprt->kref))
2156		return xprt;
2157	return NULL;
2158}
2159EXPORT_SYMBOL_GPL(xprt_get);
2160
2161/**
2162 * xprt_put - release a reference to an RPC transport.
2163 * @xprt: pointer to the transport
2164 *
2165 */
2166void xprt_put(struct rpc_xprt *xprt)
2167{
2168	if (xprt != NULL)
2169		kref_put(&xprt->kref, xprt_destroy_kref);
2170}
2171EXPORT_SYMBOL_GPL(xprt_put);
2172
2173void xprt_set_offline_locked(struct rpc_xprt *xprt, struct rpc_xprt_switch *xps)
2174{
2175	if (!test_and_set_bit(XPRT_OFFLINE, &xprt->state)) {
2176		spin_lock(&xps->xps_lock);
2177		xps->xps_nactive--;
2178		spin_unlock(&xps->xps_lock);
2179	}
2180}
2181
2182void xprt_set_online_locked(struct rpc_xprt *xprt, struct rpc_xprt_switch *xps)
2183{
2184	if (test_and_clear_bit(XPRT_OFFLINE, &xprt->state)) {
2185		spin_lock(&xps->xps_lock);
2186		xps->xps_nactive++;
2187		spin_unlock(&xps->xps_lock);
2188	}
2189}
2190
2191void xprt_delete_locked(struct rpc_xprt *xprt, struct rpc_xprt_switch *xps)
2192{
2193	if (test_and_set_bit(XPRT_REMOVE, &xprt->state))
2194		return;
2195
2196	xprt_force_disconnect(xprt);
2197	if (!test_bit(XPRT_CONNECTED, &xprt->state))
2198		return;
2199
2200	if (!xprt->sending.qlen && !xprt->pending.qlen &&
2201	    !xprt->backlog.qlen && !atomic_long_read(&xprt->queuelen))
2202		rpc_xprt_switch_remove_xprt(xps, xprt, true);
2203}