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v4.6
   1/*
   2 * linux/net/sunrpc/svc.c
   3 *
   4 * High-level RPC service routines
   5 *
   6 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
   7 *
   8 * Multiple threads pools and NUMAisation
   9 * Copyright (c) 2006 Silicon Graphics, Inc.
  10 * by Greg Banks <gnb@melbourne.sgi.com>
  11 */
  12
  13#include <linux/linkage.h>
  14#include <linux/sched.h>
  15#include <linux/errno.h>
  16#include <linux/net.h>
  17#include <linux/in.h>
  18#include <linux/mm.h>
  19#include <linux/interrupt.h>
  20#include <linux/module.h>
  21#include <linux/kthread.h>
  22#include <linux/slab.h>
  23
  24#include <linux/sunrpc/types.h>
  25#include <linux/sunrpc/xdr.h>
  26#include <linux/sunrpc/stats.h>
  27#include <linux/sunrpc/svcsock.h>
  28#include <linux/sunrpc/clnt.h>
  29#include <linux/sunrpc/bc_xprt.h>
  30
  31#include <trace/events/sunrpc.h>
  32
  33#define RPCDBG_FACILITY	RPCDBG_SVCDSP
  34
  35static void svc_unregister(const struct svc_serv *serv, struct net *net);
  36
  37#define svc_serv_is_pooled(serv)    ((serv)->sv_ops->svo_function)
  38
 
 
 
 
 
 
 
 
 
 
  39#define SVC_POOL_DEFAULT	SVC_POOL_GLOBAL
  40
  41/*
  42 * Structure for mapping cpus to pools and vice versa.
  43 * Setup once during sunrpc initialisation.
  44 */
  45struct svc_pool_map svc_pool_map = {
 
 
 
 
 
 
 
 
 
  46	.mode = SVC_POOL_DEFAULT
  47};
  48EXPORT_SYMBOL_GPL(svc_pool_map);
  49
  50static DEFINE_MUTEX(svc_pool_map_mutex);/* protects svc_pool_map.count only */
  51
  52static int
  53param_set_pool_mode(const char *val, struct kernel_param *kp)
  54{
  55	int *ip = (int *)kp->arg;
  56	struct svc_pool_map *m = &svc_pool_map;
  57	int err;
  58
  59	mutex_lock(&svc_pool_map_mutex);
  60
  61	err = -EBUSY;
  62	if (m->count)
  63		goto out;
  64
  65	err = 0;
  66	if (!strncmp(val, "auto", 4))
  67		*ip = SVC_POOL_AUTO;
  68	else if (!strncmp(val, "global", 6))
  69		*ip = SVC_POOL_GLOBAL;
  70	else if (!strncmp(val, "percpu", 6))
  71		*ip = SVC_POOL_PERCPU;
  72	else if (!strncmp(val, "pernode", 7))
  73		*ip = SVC_POOL_PERNODE;
  74	else
  75		err = -EINVAL;
  76
  77out:
  78	mutex_unlock(&svc_pool_map_mutex);
  79	return err;
  80}
  81
  82static int
  83param_get_pool_mode(char *buf, struct kernel_param *kp)
  84{
  85	int *ip = (int *)kp->arg;
  86
  87	switch (*ip)
  88	{
  89	case SVC_POOL_AUTO:
  90		return strlcpy(buf, "auto", 20);
  91	case SVC_POOL_GLOBAL:
  92		return strlcpy(buf, "global", 20);
  93	case SVC_POOL_PERCPU:
  94		return strlcpy(buf, "percpu", 20);
  95	case SVC_POOL_PERNODE:
  96		return strlcpy(buf, "pernode", 20);
  97	default:
  98		return sprintf(buf, "%d", *ip);
  99	}
 100}
 101
 102module_param_call(pool_mode, param_set_pool_mode, param_get_pool_mode,
 103		 &svc_pool_map.mode, 0644);
 104
 105/*
 106 * Detect best pool mapping mode heuristically,
 107 * according to the machine's topology.
 108 */
 109static int
 110svc_pool_map_choose_mode(void)
 111{
 112	unsigned int node;
 113
 114	if (nr_online_nodes > 1) {
 115		/*
 116		 * Actually have multiple NUMA nodes,
 117		 * so split pools on NUMA node boundaries
 118		 */
 119		return SVC_POOL_PERNODE;
 120	}
 121
 122	node = first_online_node;
 123	if (nr_cpus_node(node) > 2) {
 124		/*
 125		 * Non-trivial SMP, or CONFIG_NUMA on
 126		 * non-NUMA hardware, e.g. with a generic
 127		 * x86_64 kernel on Xeons.  In this case we
 128		 * want to divide the pools on cpu boundaries.
 129		 */
 130		return SVC_POOL_PERCPU;
 131	}
 132
 133	/* default: one global pool */
 134	return SVC_POOL_GLOBAL;
 135}
 136
 137/*
 138 * Allocate the to_pool[] and pool_to[] arrays.
 139 * Returns 0 on success or an errno.
 140 */
 141static int
 142svc_pool_map_alloc_arrays(struct svc_pool_map *m, unsigned int maxpools)
 143{
 144	m->to_pool = kcalloc(maxpools, sizeof(unsigned int), GFP_KERNEL);
 145	if (!m->to_pool)
 146		goto fail;
 147	m->pool_to = kcalloc(maxpools, sizeof(unsigned int), GFP_KERNEL);
 148	if (!m->pool_to)
 149		goto fail_free;
 150
 151	return 0;
 152
 153fail_free:
 154	kfree(m->to_pool);
 155	m->to_pool = NULL;
 156fail:
 157	return -ENOMEM;
 158}
 159
 160/*
 161 * Initialise the pool map for SVC_POOL_PERCPU mode.
 162 * Returns number of pools or <0 on error.
 163 */
 164static int
 165svc_pool_map_init_percpu(struct svc_pool_map *m)
 166{
 167	unsigned int maxpools = nr_cpu_ids;
 168	unsigned int pidx = 0;
 169	unsigned int cpu;
 170	int err;
 171
 172	err = svc_pool_map_alloc_arrays(m, maxpools);
 173	if (err)
 174		return err;
 175
 176	for_each_online_cpu(cpu) {
 177		BUG_ON(pidx >= maxpools);
 178		m->to_pool[cpu] = pidx;
 179		m->pool_to[pidx] = cpu;
 180		pidx++;
 181	}
 182	/* cpus brought online later all get mapped to pool0, sorry */
 183
 184	return pidx;
 185};
 186
 187
 188/*
 189 * Initialise the pool map for SVC_POOL_PERNODE mode.
 190 * Returns number of pools or <0 on error.
 191 */
 192static int
 193svc_pool_map_init_pernode(struct svc_pool_map *m)
 194{
 195	unsigned int maxpools = nr_node_ids;
 196	unsigned int pidx = 0;
 197	unsigned int node;
 198	int err;
 199
 200	err = svc_pool_map_alloc_arrays(m, maxpools);
 201	if (err)
 202		return err;
 203
 204	for_each_node_with_cpus(node) {
 205		/* some architectures (e.g. SN2) have cpuless nodes */
 206		BUG_ON(pidx > maxpools);
 207		m->to_pool[node] = pidx;
 208		m->pool_to[pidx] = node;
 209		pidx++;
 210	}
 211	/* nodes brought online later all get mapped to pool0, sorry */
 212
 213	return pidx;
 214}
 215
 216
 217/*
 218 * Add a reference to the global map of cpus to pools (and
 219 * vice versa).  Initialise the map if we're the first user.
 220 * Returns the number of pools.
 221 */
 222unsigned int
 223svc_pool_map_get(void)
 224{
 225	struct svc_pool_map *m = &svc_pool_map;
 226	int npools = -1;
 227
 228	mutex_lock(&svc_pool_map_mutex);
 229
 230	if (m->count++) {
 231		mutex_unlock(&svc_pool_map_mutex);
 232		return m->npools;
 233	}
 234
 235	if (m->mode == SVC_POOL_AUTO)
 236		m->mode = svc_pool_map_choose_mode();
 237
 238	switch (m->mode) {
 239	case SVC_POOL_PERCPU:
 240		npools = svc_pool_map_init_percpu(m);
 241		break;
 242	case SVC_POOL_PERNODE:
 243		npools = svc_pool_map_init_pernode(m);
 244		break;
 245	}
 246
 247	if (npools < 0) {
 248		/* default, or memory allocation failure */
 249		npools = 1;
 250		m->mode = SVC_POOL_GLOBAL;
 251	}
 252	m->npools = npools;
 253
 254	mutex_unlock(&svc_pool_map_mutex);
 255	return m->npools;
 256}
 257EXPORT_SYMBOL_GPL(svc_pool_map_get);
 258
 259/*
 260 * Drop a reference to the global map of cpus to pools.
 261 * When the last reference is dropped, the map data is
 262 * freed; this allows the sysadmin to change the pool
 263 * mode using the pool_mode module option without
 264 * rebooting or re-loading sunrpc.ko.
 265 */
 266void
 267svc_pool_map_put(void)
 268{
 269	struct svc_pool_map *m = &svc_pool_map;
 270
 271	mutex_lock(&svc_pool_map_mutex);
 272
 273	if (!--m->count) {
 
 274		kfree(m->to_pool);
 275		m->to_pool = NULL;
 276		kfree(m->pool_to);
 277		m->pool_to = NULL;
 278		m->npools = 0;
 279	}
 280
 281	mutex_unlock(&svc_pool_map_mutex);
 282}
 283EXPORT_SYMBOL_GPL(svc_pool_map_put);
 284
 285static int svc_pool_map_get_node(unsigned int pidx)
 286{
 287	const struct svc_pool_map *m = &svc_pool_map;
 288
 289	if (m->count) {
 290		if (m->mode == SVC_POOL_PERCPU)
 291			return cpu_to_node(m->pool_to[pidx]);
 292		if (m->mode == SVC_POOL_PERNODE)
 293			return m->pool_to[pidx];
 294	}
 295	return NUMA_NO_NODE;
 296}
 297/*
 298 * Set the given thread's cpus_allowed mask so that it
 299 * will only run on cpus in the given pool.
 300 */
 301static inline void
 302svc_pool_map_set_cpumask(struct task_struct *task, unsigned int pidx)
 303{
 304	struct svc_pool_map *m = &svc_pool_map;
 305	unsigned int node = m->pool_to[pidx];
 306
 307	/*
 308	 * The caller checks for sv_nrpools > 1, which
 309	 * implies that we've been initialized.
 310	 */
 311	WARN_ON_ONCE(m->count == 0);
 312	if (m->count == 0)
 313		return;
 314
 315	switch (m->mode) {
 316	case SVC_POOL_PERCPU:
 317	{
 318		set_cpus_allowed_ptr(task, cpumask_of(node));
 319		break;
 320	}
 321	case SVC_POOL_PERNODE:
 322	{
 323		set_cpus_allowed_ptr(task, cpumask_of_node(node));
 324		break;
 325	}
 326	}
 327}
 328
 329/*
 330 * Use the mapping mode to choose a pool for a given CPU.
 331 * Used when enqueueing an incoming RPC.  Always returns
 332 * a non-NULL pool pointer.
 333 */
 334struct svc_pool *
 335svc_pool_for_cpu(struct svc_serv *serv, int cpu)
 336{
 337	struct svc_pool_map *m = &svc_pool_map;
 338	unsigned int pidx = 0;
 339
 340	/*
 341	 * An uninitialised map happens in a pure client when
 342	 * lockd is brought up, so silently treat it the
 343	 * same as SVC_POOL_GLOBAL.
 344	 */
 345	if (svc_serv_is_pooled(serv)) {
 346		switch (m->mode) {
 347		case SVC_POOL_PERCPU:
 348			pidx = m->to_pool[cpu];
 349			break;
 350		case SVC_POOL_PERNODE:
 351			pidx = m->to_pool[cpu_to_node(cpu)];
 352			break;
 353		}
 354	}
 355	return &serv->sv_pools[pidx % serv->sv_nrpools];
 356}
 357
 358int svc_rpcb_setup(struct svc_serv *serv, struct net *net)
 359{
 360	int err;
 361
 362	err = rpcb_create_local(net);
 363	if (err)
 364		return err;
 365
 366	/* Remove any stale portmap registrations */
 367	svc_unregister(serv, net);
 368	return 0;
 369}
 370EXPORT_SYMBOL_GPL(svc_rpcb_setup);
 371
 372void svc_rpcb_cleanup(struct svc_serv *serv, struct net *net)
 373{
 374	svc_unregister(serv, net);
 375	rpcb_put_local(net);
 376}
 377EXPORT_SYMBOL_GPL(svc_rpcb_cleanup);
 378
 379static int svc_uses_rpcbind(struct svc_serv *serv)
 380{
 381	struct svc_program	*progp;
 382	unsigned int		i;
 383
 384	for (progp = serv->sv_program; progp; progp = progp->pg_next) {
 385		for (i = 0; i < progp->pg_nvers; i++) {
 386			if (progp->pg_vers[i] == NULL)
 387				continue;
 388			if (progp->pg_vers[i]->vs_hidden == 0)
 389				return 1;
 390		}
 391	}
 392
 393	return 0;
 394}
 395
 396int svc_bind(struct svc_serv *serv, struct net *net)
 397{
 398	if (!svc_uses_rpcbind(serv))
 399		return 0;
 400	return svc_rpcb_setup(serv, net);
 401}
 402EXPORT_SYMBOL_GPL(svc_bind);
 403
 404/*
 405 * Create an RPC service
 406 */
 407static struct svc_serv *
 408__svc_create(struct svc_program *prog, unsigned int bufsize, int npools,
 409	     struct svc_serv_ops *ops)
 410{
 411	struct svc_serv	*serv;
 412	unsigned int vers;
 413	unsigned int xdrsize;
 414	unsigned int i;
 415
 416	if (!(serv = kzalloc(sizeof(*serv), GFP_KERNEL)))
 417		return NULL;
 418	serv->sv_name      = prog->pg_name;
 419	serv->sv_program   = prog;
 420	serv->sv_nrthreads = 1;
 421	serv->sv_stats     = prog->pg_stats;
 422	if (bufsize > RPCSVC_MAXPAYLOAD)
 423		bufsize = RPCSVC_MAXPAYLOAD;
 424	serv->sv_max_payload = bufsize? bufsize : 4096;
 425	serv->sv_max_mesg  = roundup(serv->sv_max_payload + PAGE_SIZE, PAGE_SIZE);
 426	serv->sv_ops = ops;
 427	xdrsize = 0;
 428	while (prog) {
 429		prog->pg_lovers = prog->pg_nvers-1;
 430		for (vers=0; vers<prog->pg_nvers ; vers++)
 431			if (prog->pg_vers[vers]) {
 432				prog->pg_hivers = vers;
 433				if (prog->pg_lovers > vers)
 434					prog->pg_lovers = vers;
 435				if (prog->pg_vers[vers]->vs_xdrsize > xdrsize)
 436					xdrsize = prog->pg_vers[vers]->vs_xdrsize;
 437			}
 438		prog = prog->pg_next;
 439	}
 440	serv->sv_xdrsize   = xdrsize;
 441	INIT_LIST_HEAD(&serv->sv_tempsocks);
 442	INIT_LIST_HEAD(&serv->sv_permsocks);
 443	init_timer(&serv->sv_temptimer);
 444	spin_lock_init(&serv->sv_lock);
 445
 446	serv->sv_nrpools = npools;
 447	serv->sv_pools =
 448		kcalloc(serv->sv_nrpools, sizeof(struct svc_pool),
 449			GFP_KERNEL);
 450	if (!serv->sv_pools) {
 451		kfree(serv);
 452		return NULL;
 453	}
 454
 455	for (i = 0; i < serv->sv_nrpools; i++) {
 456		struct svc_pool *pool = &serv->sv_pools[i];
 457
 458		dprintk("svc: initialising pool %u for %s\n",
 459				i, serv->sv_name);
 460
 461		pool->sp_id = i;
 
 462		INIT_LIST_HEAD(&pool->sp_sockets);
 463		INIT_LIST_HEAD(&pool->sp_all_threads);
 464		spin_lock_init(&pool->sp_lock);
 465	}
 466
 
 
 
 467	return serv;
 468}
 469
 470struct svc_serv *
 471svc_create(struct svc_program *prog, unsigned int bufsize,
 472	   struct svc_serv_ops *ops)
 473{
 474	return __svc_create(prog, bufsize, /*npools*/1, ops);
 475}
 476EXPORT_SYMBOL_GPL(svc_create);
 477
 478struct svc_serv *
 479svc_create_pooled(struct svc_program *prog, unsigned int bufsize,
 480		  struct svc_serv_ops *ops)
 
 481{
 482	struct svc_serv *serv;
 483	unsigned int npools = svc_pool_map_get();
 484
 485	serv = __svc_create(prog, bufsize, npools, ops);
 486	if (!serv)
 487		goto out_err;
 488	return serv;
 489out_err:
 490	svc_pool_map_put();
 491	return NULL;
 492}
 493EXPORT_SYMBOL_GPL(svc_create_pooled);
 494
 495void svc_shutdown_net(struct svc_serv *serv, struct net *net)
 496{
 497	svc_close_net(serv, net);
 
 498
 499	if (serv->sv_ops->svo_shutdown)
 500		serv->sv_ops->svo_shutdown(serv, net);
 501}
 502EXPORT_SYMBOL_GPL(svc_shutdown_net);
 503
 504/*
 505 * Destroy an RPC service. Should be called with appropriate locking to
 506 * protect the sv_nrthreads, sv_permsocks and sv_tempsocks.
 507 */
 508void
 509svc_destroy(struct svc_serv *serv)
 510{
 511	dprintk("svc: svc_destroy(%s, %d)\n",
 512				serv->sv_program->pg_name,
 513				serv->sv_nrthreads);
 514
 515	if (serv->sv_nrthreads) {
 516		if (--(serv->sv_nrthreads) != 0) {
 517			svc_sock_update_bufs(serv);
 518			return;
 519		}
 520	} else
 521		printk("svc_destroy: no threads for serv=%p!\n", serv);
 522
 523	del_timer_sync(&serv->sv_temptimer);
 524
 525	/*
 526	 * The last user is gone and thus all sockets have to be destroyed to
 527	 * the point. Check this.
 528	 */
 
 
 
 529	BUG_ON(!list_empty(&serv->sv_permsocks));
 530	BUG_ON(!list_empty(&serv->sv_tempsocks));
 531
 532	cache_clean_deferred(serv);
 533
 534	if (svc_serv_is_pooled(serv))
 535		svc_pool_map_put();
 536
 
 537	kfree(serv->sv_pools);
 538	kfree(serv);
 539}
 540EXPORT_SYMBOL_GPL(svc_destroy);
 541
 542/*
 543 * Allocate an RPC server's buffer space.
 544 * We allocate pages and place them in rq_argpages.
 545 */
 546static int
 547svc_init_buffer(struct svc_rqst *rqstp, unsigned int size, int node)
 548{
 549	unsigned int pages, arghi;
 550
 551	/* bc_xprt uses fore channel allocated buffers */
 552	if (svc_is_backchannel(rqstp))
 553		return 1;
 554
 555	pages = size / PAGE_SIZE + 1; /* extra page as we hold both request and reply.
 556				       * We assume one is at most one page
 557				       */
 558	arghi = 0;
 559	WARN_ON_ONCE(pages > RPCSVC_MAXPAGES);
 560	if (pages > RPCSVC_MAXPAGES)
 561		pages = RPCSVC_MAXPAGES;
 562	while (pages) {
 563		struct page *p = alloc_pages_node(node, GFP_KERNEL, 0);
 564		if (!p)
 565			break;
 566		rqstp->rq_pages[arghi++] = p;
 567		pages--;
 568	}
 569	return pages == 0;
 570}
 571
 572/*
 573 * Release an RPC server buffer
 574 */
 575static void
 576svc_release_buffer(struct svc_rqst *rqstp)
 577{
 578	unsigned int i;
 579
 580	for (i = 0; i < ARRAY_SIZE(rqstp->rq_pages); i++)
 581		if (rqstp->rq_pages[i])
 582			put_page(rqstp->rq_pages[i]);
 583}
 584
 585struct svc_rqst *
 586svc_rqst_alloc(struct svc_serv *serv, struct svc_pool *pool, int node)
 587{
 588	struct svc_rqst	*rqstp;
 589
 590	rqstp = kzalloc_node(sizeof(*rqstp), GFP_KERNEL, node);
 591	if (!rqstp)
 592		return rqstp;
 
 
 593
 594	__set_bit(RQ_BUSY, &rqstp->rq_flags);
 595	spin_lock_init(&rqstp->rq_lock);
 
 
 
 596	rqstp->rq_server = serv;
 597	rqstp->rq_pool = pool;
 598
 599	rqstp->rq_argp = kmalloc_node(serv->sv_xdrsize, GFP_KERNEL, node);
 600	if (!rqstp->rq_argp)
 601		goto out_enomem;
 602
 603	rqstp->rq_resp = kmalloc_node(serv->sv_xdrsize, GFP_KERNEL, node);
 604	if (!rqstp->rq_resp)
 605		goto out_enomem;
 606
 607	if (!svc_init_buffer(rqstp, serv->sv_max_mesg, node))
 608		goto out_enomem;
 609
 610	return rqstp;
 
 
 611out_enomem:
 612	svc_rqst_free(rqstp);
 613	return NULL;
 614}
 615EXPORT_SYMBOL_GPL(svc_rqst_alloc);
 616
 617struct svc_rqst *
 618svc_prepare_thread(struct svc_serv *serv, struct svc_pool *pool, int node)
 619{
 620	struct svc_rqst	*rqstp;
 621
 622	rqstp = svc_rqst_alloc(serv, pool, node);
 623	if (!rqstp)
 624		return ERR_PTR(-ENOMEM);
 625
 626	serv->sv_nrthreads++;
 627	spin_lock_bh(&pool->sp_lock);
 628	pool->sp_nrthreads++;
 629	list_add_rcu(&rqstp->rq_all, &pool->sp_all_threads);
 630	spin_unlock_bh(&pool->sp_lock);
 631	return rqstp;
 632}
 633EXPORT_SYMBOL_GPL(svc_prepare_thread);
 634
 635/*
 636 * Choose a pool in which to create a new thread, for svc_set_num_threads
 637 */
 638static inline struct svc_pool *
 639choose_pool(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)
 640{
 641	if (pool != NULL)
 642		return pool;
 643
 644	return &serv->sv_pools[(*state)++ % serv->sv_nrpools];
 645}
 646
 647/*
 648 * Choose a thread to kill, for svc_set_num_threads
 649 */
 650static inline struct task_struct *
 651choose_victim(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)
 652{
 653	unsigned int i;
 654	struct task_struct *task = NULL;
 655
 656	if (pool != NULL) {
 657		spin_lock_bh(&pool->sp_lock);
 658	} else {
 659		/* choose a pool in round-robin fashion */
 660		for (i = 0; i < serv->sv_nrpools; i++) {
 661			pool = &serv->sv_pools[--(*state) % serv->sv_nrpools];
 662			spin_lock_bh(&pool->sp_lock);
 663			if (!list_empty(&pool->sp_all_threads))
 664				goto found_pool;
 665			spin_unlock_bh(&pool->sp_lock);
 666		}
 667		return NULL;
 668	}
 669
 670found_pool:
 671	if (!list_empty(&pool->sp_all_threads)) {
 672		struct svc_rqst *rqstp;
 673
 674		/*
 675		 * Remove from the pool->sp_all_threads list
 676		 * so we don't try to kill it again.
 677		 */
 678		rqstp = list_entry(pool->sp_all_threads.next, struct svc_rqst, rq_all);
 679		set_bit(RQ_VICTIM, &rqstp->rq_flags);
 680		list_del_rcu(&rqstp->rq_all);
 681		task = rqstp->rq_task;
 682	}
 683	spin_unlock_bh(&pool->sp_lock);
 684
 685	return task;
 686}
 687
 688/*
 689 * Create or destroy enough new threads to make the number
 690 * of threads the given number.  If `pool' is non-NULL, applies
 691 * only to threads in that pool, otherwise round-robins between
 692 * all pools.  Caller must ensure that mutual exclusion between this and
 693 * server startup or shutdown.
 694 *
 695 * Destroying threads relies on the service threads filling in
 696 * rqstp->rq_task, which only the nfs ones do.  Assumes the serv
 697 * has been created using svc_create_pooled().
 698 *
 699 * Based on code that used to be in nfsd_svc() but tweaked
 700 * to be pool-aware.
 701 */
 702int
 703svc_set_num_threads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
 704{
 705	struct svc_rqst	*rqstp;
 706	struct task_struct *task;
 707	struct svc_pool *chosen_pool;
 708	int error = 0;
 709	unsigned int state = serv->sv_nrthreads-1;
 710	int node;
 711
 712	if (pool == NULL) {
 713		/* The -1 assumes caller has done a svc_get() */
 714		nrservs -= (serv->sv_nrthreads-1);
 715	} else {
 716		spin_lock_bh(&pool->sp_lock);
 717		nrservs -= pool->sp_nrthreads;
 718		spin_unlock_bh(&pool->sp_lock);
 719	}
 720
 721	/* create new threads */
 722	while (nrservs > 0) {
 723		nrservs--;
 724		chosen_pool = choose_pool(serv, pool, &state);
 725
 726		node = svc_pool_map_get_node(chosen_pool->sp_id);
 727		rqstp = svc_prepare_thread(serv, chosen_pool, node);
 728		if (IS_ERR(rqstp)) {
 729			error = PTR_ERR(rqstp);
 730			break;
 731		}
 732
 733		__module_get(serv->sv_ops->svo_module);
 734		task = kthread_create_on_node(serv->sv_ops->svo_function, rqstp,
 735					      node, "%s", serv->sv_name);
 736		if (IS_ERR(task)) {
 737			error = PTR_ERR(task);
 738			module_put(serv->sv_ops->svo_module);
 739			svc_exit_thread(rqstp);
 740			break;
 741		}
 742
 743		rqstp->rq_task = task;
 744		if (serv->sv_nrpools > 1)
 745			svc_pool_map_set_cpumask(task, chosen_pool->sp_id);
 746
 747		svc_sock_update_bufs(serv);
 748		wake_up_process(task);
 749	}
 750	/* destroy old threads */
 751	while (nrservs < 0 &&
 752	       (task = choose_victim(serv, pool, &state)) != NULL) {
 753		send_sig(SIGINT, task, 1);
 754		nrservs++;
 755	}
 756
 757	return error;
 758}
 759EXPORT_SYMBOL_GPL(svc_set_num_threads);
 760
 761/*
 762 * Called from a server thread as it's exiting. Caller must hold the "service
 763 * mutex" for the service.
 764 */
 765void
 766svc_rqst_free(struct svc_rqst *rqstp)
 767{
 
 
 
 768	svc_release_buffer(rqstp);
 769	kfree(rqstp->rq_resp);
 770	kfree(rqstp->rq_argp);
 771	kfree(rqstp->rq_auth_data);
 772	kfree_rcu(rqstp, rq_rcu_head);
 773}
 774EXPORT_SYMBOL_GPL(svc_rqst_free);
 775
 776void
 777svc_exit_thread(struct svc_rqst *rqstp)
 778{
 779	struct svc_serv	*serv = rqstp->rq_server;
 780	struct svc_pool	*pool = rqstp->rq_pool;
 781
 782	spin_lock_bh(&pool->sp_lock);
 783	pool->sp_nrthreads--;
 784	if (!test_and_set_bit(RQ_VICTIM, &rqstp->rq_flags))
 785		list_del_rcu(&rqstp->rq_all);
 786	spin_unlock_bh(&pool->sp_lock);
 787
 788	svc_rqst_free(rqstp);
 789
 790	/* Release the server */
 791	if (serv)
 792		svc_destroy(serv);
 793}
 794EXPORT_SYMBOL_GPL(svc_exit_thread);
 795
 796/*
 797 * Register an "inet" protocol family netid with the local
 798 * rpcbind daemon via an rpcbind v4 SET request.
 799 *
 800 * No netconfig infrastructure is available in the kernel, so
 801 * we map IP_ protocol numbers to netids by hand.
 802 *
 803 * Returns zero on success; a negative errno value is returned
 804 * if any error occurs.
 805 */
 806static int __svc_rpcb_register4(struct net *net, const u32 program,
 807				const u32 version,
 808				const unsigned short protocol,
 809				const unsigned short port)
 810{
 811	const struct sockaddr_in sin = {
 812		.sin_family		= AF_INET,
 813		.sin_addr.s_addr	= htonl(INADDR_ANY),
 814		.sin_port		= htons(port),
 815	};
 816	const char *netid;
 817	int error;
 818
 819	switch (protocol) {
 820	case IPPROTO_UDP:
 821		netid = RPCBIND_NETID_UDP;
 822		break;
 823	case IPPROTO_TCP:
 824		netid = RPCBIND_NETID_TCP;
 825		break;
 826	default:
 827		return -ENOPROTOOPT;
 828	}
 829
 830	error = rpcb_v4_register(net, program, version,
 831					(const struct sockaddr *)&sin, netid);
 832
 833	/*
 834	 * User space didn't support rpcbind v4, so retry this
 835	 * registration request with the legacy rpcbind v2 protocol.
 836	 */
 837	if (error == -EPROTONOSUPPORT)
 838		error = rpcb_register(net, program, version, protocol, port);
 839
 840	return error;
 841}
 842
 843#if IS_ENABLED(CONFIG_IPV6)
 844/*
 845 * Register an "inet6" protocol family netid with the local
 846 * rpcbind daemon via an rpcbind v4 SET request.
 847 *
 848 * No netconfig infrastructure is available in the kernel, so
 849 * we map IP_ protocol numbers to netids by hand.
 850 *
 851 * Returns zero on success; a negative errno value is returned
 852 * if any error occurs.
 853 */
 854static int __svc_rpcb_register6(struct net *net, const u32 program,
 855				const u32 version,
 856				const unsigned short protocol,
 857				const unsigned short port)
 858{
 859	const struct sockaddr_in6 sin6 = {
 860		.sin6_family		= AF_INET6,
 861		.sin6_addr		= IN6ADDR_ANY_INIT,
 862		.sin6_port		= htons(port),
 863	};
 864	const char *netid;
 865	int error;
 866
 867	switch (protocol) {
 868	case IPPROTO_UDP:
 869		netid = RPCBIND_NETID_UDP6;
 870		break;
 871	case IPPROTO_TCP:
 872		netid = RPCBIND_NETID_TCP6;
 873		break;
 874	default:
 875		return -ENOPROTOOPT;
 876	}
 877
 878	error = rpcb_v4_register(net, program, version,
 879					(const struct sockaddr *)&sin6, netid);
 880
 881	/*
 882	 * User space didn't support rpcbind version 4, so we won't
 883	 * use a PF_INET6 listener.
 884	 */
 885	if (error == -EPROTONOSUPPORT)
 886		error = -EAFNOSUPPORT;
 887
 888	return error;
 889}
 890#endif	/* IS_ENABLED(CONFIG_IPV6) */
 891
 892/*
 893 * Register a kernel RPC service via rpcbind version 4.
 894 *
 895 * Returns zero on success; a negative errno value is returned
 896 * if any error occurs.
 897 */
 898static int __svc_register(struct net *net, const char *progname,
 899			  const u32 program, const u32 version,
 900			  const int family,
 901			  const unsigned short protocol,
 902			  const unsigned short port)
 903{
 904	int error = -EAFNOSUPPORT;
 905
 906	switch (family) {
 907	case PF_INET:
 908		error = __svc_rpcb_register4(net, program, version,
 909						protocol, port);
 910		break;
 911#if IS_ENABLED(CONFIG_IPV6)
 912	case PF_INET6:
 913		error = __svc_rpcb_register6(net, program, version,
 914						protocol, port);
 915#endif
 916	}
 917
 
 
 
 918	return error;
 919}
 920
 921/**
 922 * svc_register - register an RPC service with the local portmapper
 923 * @serv: svc_serv struct for the service to register
 924 * @net: net namespace for the service to register
 925 * @family: protocol family of service's listener socket
 926 * @proto: transport protocol number to advertise
 927 * @port: port to advertise
 928 *
 929 * Service is registered for any address in the passed-in protocol family
 930 */
 931int svc_register(const struct svc_serv *serv, struct net *net,
 932		 const int family, const unsigned short proto,
 933		 const unsigned short port)
 934{
 935	struct svc_program	*progp;
 936	struct svc_version	*vers;
 937	unsigned int		i;
 938	int			error = 0;
 939
 940	WARN_ON_ONCE(proto == 0 && port == 0);
 941	if (proto == 0 && port == 0)
 942		return -EINVAL;
 943
 944	for (progp = serv->sv_program; progp; progp = progp->pg_next) {
 945		for (i = 0; i < progp->pg_nvers; i++) {
 946			vers = progp->pg_vers[i];
 947			if (vers == NULL)
 948				continue;
 949
 950			dprintk("svc: svc_register(%sv%d, %s, %u, %u)%s\n",
 951					progp->pg_name,
 952					i,
 953					proto == IPPROTO_UDP?  "udp" : "tcp",
 954					port,
 955					family,
 956					vers->vs_hidden ?
 957					" (but not telling portmap)" : "");
 958
 959			if (vers->vs_hidden)
 960				continue;
 961
 962			error = __svc_register(net, progp->pg_name, progp->pg_prog,
 963						i, family, proto, port);
 964
 965			if (vers->vs_rpcb_optnl) {
 966				error = 0;
 967				continue;
 968			}
 969
 970			if (error < 0) {
 971				printk(KERN_WARNING "svc: failed to register "
 972					"%sv%u RPC service (errno %d).\n",
 973					progp->pg_name, i, -error);
 974				break;
 975			}
 976		}
 977	}
 978
 979	return error;
 980}
 981
 982/*
 983 * If user space is running rpcbind, it should take the v4 UNSET
 984 * and clear everything for this [program, version].  If user space
 985 * is running portmap, it will reject the v4 UNSET, but won't have
 986 * any "inet6" entries anyway.  So a PMAP_UNSET should be sufficient
 987 * in this case to clear all existing entries for [program, version].
 988 */
 989static void __svc_unregister(struct net *net, const u32 program, const u32 version,
 990			     const char *progname)
 991{
 992	int error;
 993
 994	error = rpcb_v4_register(net, program, version, NULL, "");
 995
 996	/*
 997	 * User space didn't support rpcbind v4, so retry this
 998	 * request with the legacy rpcbind v2 protocol.
 999	 */
1000	if (error == -EPROTONOSUPPORT)
1001		error = rpcb_register(net, program, version, 0, 0);
1002
1003	dprintk("svc: %s(%sv%u), error %d\n",
1004			__func__, progname, version, error);
1005}
1006
1007/*
1008 * All netids, bind addresses and ports registered for [program, version]
1009 * are removed from the local rpcbind database (if the service is not
1010 * hidden) to make way for a new instance of the service.
1011 *
1012 * The result of unregistration is reported via dprintk for those who want
1013 * verification of the result, but is otherwise not important.
1014 */
1015static void svc_unregister(const struct svc_serv *serv, struct net *net)
1016{
1017	struct svc_program *progp;
1018	unsigned long flags;
1019	unsigned int i;
1020
1021	clear_thread_flag(TIF_SIGPENDING);
1022
1023	for (progp = serv->sv_program; progp; progp = progp->pg_next) {
1024		for (i = 0; i < progp->pg_nvers; i++) {
1025			if (progp->pg_vers[i] == NULL)
1026				continue;
1027			if (progp->pg_vers[i]->vs_hidden)
1028				continue;
1029
1030			dprintk("svc: attempting to unregister %sv%u\n",
1031				progp->pg_name, i);
1032			__svc_unregister(net, progp->pg_prog, i, progp->pg_name);
1033		}
1034	}
1035
1036	spin_lock_irqsave(&current->sighand->siglock, flags);
1037	recalc_sigpending();
1038	spin_unlock_irqrestore(&current->sighand->siglock, flags);
1039}
1040
1041/*
1042 * dprintk the given error with the address of the client that caused it.
1043 */
1044#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
1045static __printf(2, 3)
1046void svc_printk(struct svc_rqst *rqstp, const char *fmt, ...)
1047{
1048	struct va_format vaf;
1049	va_list args;
 
1050	char 	buf[RPC_MAX_ADDRBUFLEN];
1051
1052	va_start(args, fmt);
1053
1054	vaf.fmt = fmt;
1055	vaf.va = &args;
1056
1057	dprintk("svc: %s: %pV", svc_print_addr(rqstp, buf, sizeof(buf)), &vaf);
 
1058
 
 
1059	va_end(args);
 
 
1060}
1061#else
1062static __printf(2,3) void svc_printk(struct svc_rqst *rqstp, const char *fmt, ...) {}
1063#endif
1064
1065/*
1066 * Common routine for processing the RPC request.
1067 */
1068static int
1069svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
1070{
1071	struct svc_program	*progp;
1072	struct svc_version	*versp = NULL;	/* compiler food */
1073	struct svc_procedure	*procp = NULL;
1074	struct svc_serv		*serv = rqstp->rq_server;
1075	kxdrproc_t		xdr;
1076	__be32			*statp;
1077	u32			prog, vers, proc;
1078	__be32			auth_stat, rpc_stat;
1079	int			auth_res;
1080	__be32			*reply_statp;
1081
1082	rpc_stat = rpc_success;
1083
1084	if (argv->iov_len < 6*4)
1085		goto err_short_len;
1086
1087	/* Will be turned off only in gss privacy case: */
1088	set_bit(RQ_SPLICE_OK, &rqstp->rq_flags);
1089	/* Will be turned off only when NFSv4 Sessions are used */
1090	set_bit(RQ_USEDEFERRAL, &rqstp->rq_flags);
1091	clear_bit(RQ_DROPME, &rqstp->rq_flags);
1092
1093	/* Setup reply header */
1094	rqstp->rq_xprt->xpt_ops->xpo_prep_reply_hdr(rqstp);
1095
1096	svc_putu32(resv, rqstp->rq_xid);
1097
1098	vers = svc_getnl(argv);
1099
1100	/* First words of reply: */
1101	svc_putnl(resv, 1);		/* REPLY */
1102
1103	if (vers != 2)		/* RPC version number */
1104		goto err_bad_rpc;
1105
1106	/* Save position in case we later decide to reject: */
1107	reply_statp = resv->iov_base + resv->iov_len;
1108
1109	svc_putnl(resv, 0);		/* ACCEPT */
1110
1111	rqstp->rq_prog = prog = svc_getnl(argv);	/* program number */
1112	rqstp->rq_vers = vers = svc_getnl(argv);	/* version number */
1113	rqstp->rq_proc = proc = svc_getnl(argv);	/* procedure number */
1114
 
 
1115	for (progp = serv->sv_program; progp; progp = progp->pg_next)
1116		if (prog == progp->pg_prog)
1117			break;
1118
1119	/*
1120	 * Decode auth data, and add verifier to reply buffer.
1121	 * We do this before anything else in order to get a decent
1122	 * auth verifier.
1123	 */
1124	auth_res = svc_authenticate(rqstp, &auth_stat);
1125	/* Also give the program a chance to reject this call: */
1126	if (auth_res == SVC_OK && progp) {
1127		auth_stat = rpc_autherr_badcred;
1128		auth_res = progp->pg_authenticate(rqstp);
1129	}
1130	switch (auth_res) {
1131	case SVC_OK:
1132		break;
1133	case SVC_GARBAGE:
1134		goto err_garbage;
1135	case SVC_SYSERR:
1136		rpc_stat = rpc_system_err;
1137		goto err_bad;
1138	case SVC_DENIED:
1139		goto err_bad_auth;
1140	case SVC_CLOSE:
1141		if (test_bit(XPT_TEMP, &rqstp->rq_xprt->xpt_flags))
1142			svc_close_xprt(rqstp->rq_xprt);
1143	case SVC_DROP:
1144		goto dropit;
1145	case SVC_COMPLETE:
1146		goto sendit;
1147	}
1148
1149	if (progp == NULL)
1150		goto err_bad_prog;
1151
1152	if (vers >= progp->pg_nvers ||
1153	  !(versp = progp->pg_vers[vers]))
1154		goto err_bad_vers;
1155
1156	procp = versp->vs_proc + proc;
1157	if (proc >= versp->vs_nproc || !procp->pc_func)
1158		goto err_bad_proc;
1159	rqstp->rq_procinfo = procp;
1160
1161	/* Syntactic check complete */
1162	serv->sv_stats->rpccnt++;
1163
1164	/* Build the reply header. */
1165	statp = resv->iov_base +resv->iov_len;
1166	svc_putnl(resv, RPC_SUCCESS);
1167
1168	/* Bump per-procedure stats counter */
1169	procp->pc_count++;
1170
1171	/* Initialize storage for argp and resp */
1172	memset(rqstp->rq_argp, 0, procp->pc_argsize);
1173	memset(rqstp->rq_resp, 0, procp->pc_ressize);
1174
1175	/* un-reserve some of the out-queue now that we have a
1176	 * better idea of reply size
1177	 */
1178	if (procp->pc_xdrressize)
1179		svc_reserve_auth(rqstp, procp->pc_xdrressize<<2);
1180
1181	/* Call the function that processes the request. */
1182	if (!versp->vs_dispatch) {
1183		/* Decode arguments */
1184		xdr = procp->pc_decode;
1185		if (xdr && !xdr(rqstp, argv->iov_base, rqstp->rq_argp))
1186			goto err_garbage;
1187
1188		*statp = procp->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
1189
1190		/* Encode reply */
1191		if (test_bit(RQ_DROPME, &rqstp->rq_flags)) {
1192			if (procp->pc_release)
1193				procp->pc_release(rqstp, NULL, rqstp->rq_resp);
1194			goto dropit;
1195		}
1196		if (*statp == rpc_success &&
1197		    (xdr = procp->pc_encode) &&
1198		    !xdr(rqstp, resv->iov_base+resv->iov_len, rqstp->rq_resp)) {
1199			dprintk("svc: failed to encode reply\n");
1200			/* serv->sv_stats->rpcsystemerr++; */
1201			*statp = rpc_system_err;
1202		}
1203	} else {
1204		dprintk("svc: calling dispatcher\n");
1205		if (!versp->vs_dispatch(rqstp, statp)) {
1206			/* Release reply info */
1207			if (procp->pc_release)
1208				procp->pc_release(rqstp, NULL, rqstp->rq_resp);
1209			goto dropit;
1210		}
1211	}
1212
1213	/* Check RPC status result */
1214	if (*statp != rpc_success)
1215		resv->iov_len = ((void*)statp)  - resv->iov_base + 4;
1216
1217	/* Release reply info */
1218	if (procp->pc_release)
1219		procp->pc_release(rqstp, NULL, rqstp->rq_resp);
1220
1221	if (procp->pc_encode == NULL)
1222		goto dropit;
1223
1224 sendit:
1225	if (svc_authorise(rqstp))
1226		goto dropit;
1227	return 1;		/* Caller can now send it */
1228
1229 dropit:
1230	svc_authorise(rqstp);	/* doesn't hurt to call this twice */
1231	dprintk("svc: svc_process dropit\n");
1232	return 0;
1233
1234err_short_len:
1235	svc_printk(rqstp, "short len %Zd, dropping request\n",
1236			argv->iov_len);
1237
1238	goto dropit;			/* drop request */
1239
1240err_bad_rpc:
1241	serv->sv_stats->rpcbadfmt++;
1242	svc_putnl(resv, 1);	/* REJECT */
1243	svc_putnl(resv, 0);	/* RPC_MISMATCH */
1244	svc_putnl(resv, 2);	/* Only RPCv2 supported */
1245	svc_putnl(resv, 2);
1246	goto sendit;
1247
1248err_bad_auth:
1249	dprintk("svc: authentication failed (%d)\n", ntohl(auth_stat));
1250	serv->sv_stats->rpcbadauth++;
1251	/* Restore write pointer to location of accept status: */
1252	xdr_ressize_check(rqstp, reply_statp);
1253	svc_putnl(resv, 1);	/* REJECT */
1254	svc_putnl(resv, 1);	/* AUTH_ERROR */
1255	svc_putnl(resv, ntohl(auth_stat));	/* status */
1256	goto sendit;
1257
1258err_bad_prog:
1259	dprintk("svc: unknown program %d\n", prog);
1260	serv->sv_stats->rpcbadfmt++;
1261	svc_putnl(resv, RPC_PROG_UNAVAIL);
1262	goto sendit;
1263
1264err_bad_vers:
1265	svc_printk(rqstp, "unknown version (%d for prog %d, %s)\n",
1266		       vers, prog, progp->pg_name);
1267
1268	serv->sv_stats->rpcbadfmt++;
1269	svc_putnl(resv, RPC_PROG_MISMATCH);
1270	svc_putnl(resv, progp->pg_lovers);
1271	svc_putnl(resv, progp->pg_hivers);
1272	goto sendit;
1273
1274err_bad_proc:
1275	svc_printk(rqstp, "unknown procedure (%d)\n", proc);
1276
1277	serv->sv_stats->rpcbadfmt++;
1278	svc_putnl(resv, RPC_PROC_UNAVAIL);
1279	goto sendit;
1280
1281err_garbage:
1282	svc_printk(rqstp, "failed to decode args\n");
1283
1284	rpc_stat = rpc_garbage_args;
1285err_bad:
1286	serv->sv_stats->rpcbadfmt++;
1287	svc_putnl(resv, ntohl(rpc_stat));
1288	goto sendit;
1289}
 
1290
1291/*
1292 * Process the RPC request.
1293 */
1294int
1295svc_process(struct svc_rqst *rqstp)
1296{
1297	struct kvec		*argv = &rqstp->rq_arg.head[0];
1298	struct kvec		*resv = &rqstp->rq_res.head[0];
1299	struct svc_serv		*serv = rqstp->rq_server;
1300	u32			dir;
1301
1302	/*
1303	 * Setup response xdr_buf.
1304	 * Initially it has just one page
1305	 */
1306	rqstp->rq_next_page = &rqstp->rq_respages[1];
1307	resv->iov_base = page_address(rqstp->rq_respages[0]);
1308	resv->iov_len = 0;
1309	rqstp->rq_res.pages = rqstp->rq_respages + 1;
1310	rqstp->rq_res.len = 0;
1311	rqstp->rq_res.page_base = 0;
1312	rqstp->rq_res.page_len = 0;
1313	rqstp->rq_res.buflen = PAGE_SIZE;
1314	rqstp->rq_res.tail[0].iov_base = NULL;
1315	rqstp->rq_res.tail[0].iov_len = 0;
1316
 
 
1317	dir  = svc_getnl(argv);
1318	if (dir != 0) {
1319		/* direction != CALL */
1320		svc_printk(rqstp, "bad direction %d, dropping request\n", dir);
1321		serv->sv_stats->rpcbadfmt++;
1322		goto out_drop;
 
1323	}
1324
1325	/* Returns 1 for send, 0 for drop */
1326	if (likely(svc_process_common(rqstp, argv, resv))) {
1327		int ret = svc_send(rqstp);
1328
1329		trace_svc_process(rqstp, ret);
1330		return ret;
1331	}
1332out_drop:
1333	trace_svc_process(rqstp, 0);
1334	svc_drop(rqstp);
1335	return 0;
1336}
1337EXPORT_SYMBOL_GPL(svc_process);
1338
1339#if defined(CONFIG_SUNRPC_BACKCHANNEL)
1340/*
1341 * Process a backchannel RPC request that arrived over an existing
1342 * outbound connection
1343 */
1344int
1345bc_svc_process(struct svc_serv *serv, struct rpc_rqst *req,
1346	       struct svc_rqst *rqstp)
1347{
1348	struct kvec	*argv = &rqstp->rq_arg.head[0];
1349	struct kvec	*resv = &rqstp->rq_res.head[0];
1350	struct rpc_task *task;
1351	int proc_error;
1352	int error;
1353
1354	dprintk("svc: %s(%p)\n", __func__, req);
1355
1356	/* Build the svc_rqst used by the common processing routine */
1357	rqstp->rq_xprt = serv->sv_bc_xprt;
1358	rqstp->rq_xid = req->rq_xid;
1359	rqstp->rq_prot = req->rq_xprt->prot;
1360	rqstp->rq_server = serv;
1361
1362	rqstp->rq_addrlen = sizeof(req->rq_xprt->addr);
1363	memcpy(&rqstp->rq_addr, &req->rq_xprt->addr, rqstp->rq_addrlen);
1364	memcpy(&rqstp->rq_arg, &req->rq_rcv_buf, sizeof(rqstp->rq_arg));
1365	memcpy(&rqstp->rq_res, &req->rq_snd_buf, sizeof(rqstp->rq_res));
1366
1367	/* Adjust the argument buffer length */
1368	rqstp->rq_arg.len = req->rq_private_buf.len;
1369	if (rqstp->rq_arg.len <= rqstp->rq_arg.head[0].iov_len) {
1370		rqstp->rq_arg.head[0].iov_len = rqstp->rq_arg.len;
1371		rqstp->rq_arg.page_len = 0;
1372	} else if (rqstp->rq_arg.len <= rqstp->rq_arg.head[0].iov_len +
1373			rqstp->rq_arg.page_len)
1374		rqstp->rq_arg.page_len = rqstp->rq_arg.len -
1375			rqstp->rq_arg.head[0].iov_len;
1376	else
1377		rqstp->rq_arg.len = rqstp->rq_arg.head[0].iov_len +
1378			rqstp->rq_arg.page_len;
1379
1380	/* reset result send buffer "put" position */
1381	resv->iov_len = 0;
1382
 
 
 
 
 
1383	/*
1384	 * Skip the next two words because they've already been
1385	 * processed in the transport
1386	 */
1387	svc_getu32(argv);	/* XID */
1388	svc_getnl(argv);	/* CALLDIR */
1389
1390	/* Parse and execute the bc call */
1391	proc_error = svc_process_common(rqstp, argv, resv);
1392
1393	atomic_inc(&req->rq_xprt->bc_free_slots);
1394	if (!proc_error) {
1395		/* Processing error: drop the request */
1396		xprt_free_bc_request(req);
1397		return 0;
1398	}
1399
1400	/* Finally, send the reply synchronously */
1401	memcpy(&req->rq_snd_buf, &rqstp->rq_res, sizeof(req->rq_snd_buf));
1402	task = rpc_run_bc_task(req);
1403	if (IS_ERR(task)) {
1404		error = PTR_ERR(task);
1405		goto out;
1406	}
1407
1408	WARN_ON_ONCE(atomic_read(&task->tk_count) != 1);
1409	error = task->tk_status;
1410	rpc_put_task(task);
1411
1412out:
1413	dprintk("svc: %s(), error=%d\n", __func__, error);
1414	return error;
1415}
1416EXPORT_SYMBOL_GPL(bc_svc_process);
1417#endif /* CONFIG_SUNRPC_BACKCHANNEL */
1418
1419/*
1420 * Return (transport-specific) limit on the rpc payload.
1421 */
1422u32 svc_max_payload(const struct svc_rqst *rqstp)
1423{
1424	u32 max = rqstp->rq_xprt->xpt_class->xcl_max_payload;
1425
1426	if (rqstp->rq_server->sv_max_payload < max)
1427		max = rqstp->rq_server->sv_max_payload;
1428	return max;
1429}
1430EXPORT_SYMBOL_GPL(svc_max_payload);
v3.1
   1/*
   2 * linux/net/sunrpc/svc.c
   3 *
   4 * High-level RPC service routines
   5 *
   6 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
   7 *
   8 * Multiple threads pools and NUMAisation
   9 * Copyright (c) 2006 Silicon Graphics, Inc.
  10 * by Greg Banks <gnb@melbourne.sgi.com>
  11 */
  12
  13#include <linux/linkage.h>
  14#include <linux/sched.h>
  15#include <linux/errno.h>
  16#include <linux/net.h>
  17#include <linux/in.h>
  18#include <linux/mm.h>
  19#include <linux/interrupt.h>
  20#include <linux/module.h>
  21#include <linux/kthread.h>
  22#include <linux/slab.h>
  23
  24#include <linux/sunrpc/types.h>
  25#include <linux/sunrpc/xdr.h>
  26#include <linux/sunrpc/stats.h>
  27#include <linux/sunrpc/svcsock.h>
  28#include <linux/sunrpc/clnt.h>
  29#include <linux/sunrpc/bc_xprt.h>
  30
 
 
  31#define RPCDBG_FACILITY	RPCDBG_SVCDSP
  32
  33static void svc_unregister(const struct svc_serv *serv);
  34
  35#define svc_serv_is_pooled(serv)    ((serv)->sv_function)
  36
  37/*
  38 * Mode for mapping cpus to pools.
  39 */
  40enum {
  41	SVC_POOL_AUTO = -1,	/* choose one of the others */
  42	SVC_POOL_GLOBAL,	/* no mapping, just a single global pool
  43				 * (legacy & UP mode) */
  44	SVC_POOL_PERCPU,	/* one pool per cpu */
  45	SVC_POOL_PERNODE	/* one pool per numa node */
  46};
  47#define SVC_POOL_DEFAULT	SVC_POOL_GLOBAL
  48
  49/*
  50 * Structure for mapping cpus to pools and vice versa.
  51 * Setup once during sunrpc initialisation.
  52 */
  53static struct svc_pool_map {
  54	int count;			/* How many svc_servs use us */
  55	int mode;			/* Note: int not enum to avoid
  56					 * warnings about "enumeration value
  57					 * not handled in switch" */
  58	unsigned int npools;
  59	unsigned int *pool_to;		/* maps pool id to cpu or node */
  60	unsigned int *to_pool;		/* maps cpu or node to pool id */
  61} svc_pool_map = {
  62	.count = 0,
  63	.mode = SVC_POOL_DEFAULT
  64};
 
 
  65static DEFINE_MUTEX(svc_pool_map_mutex);/* protects svc_pool_map.count only */
  66
  67static int
  68param_set_pool_mode(const char *val, struct kernel_param *kp)
  69{
  70	int *ip = (int *)kp->arg;
  71	struct svc_pool_map *m = &svc_pool_map;
  72	int err;
  73
  74	mutex_lock(&svc_pool_map_mutex);
  75
  76	err = -EBUSY;
  77	if (m->count)
  78		goto out;
  79
  80	err = 0;
  81	if (!strncmp(val, "auto", 4))
  82		*ip = SVC_POOL_AUTO;
  83	else if (!strncmp(val, "global", 6))
  84		*ip = SVC_POOL_GLOBAL;
  85	else if (!strncmp(val, "percpu", 6))
  86		*ip = SVC_POOL_PERCPU;
  87	else if (!strncmp(val, "pernode", 7))
  88		*ip = SVC_POOL_PERNODE;
  89	else
  90		err = -EINVAL;
  91
  92out:
  93	mutex_unlock(&svc_pool_map_mutex);
  94	return err;
  95}
  96
  97static int
  98param_get_pool_mode(char *buf, struct kernel_param *kp)
  99{
 100	int *ip = (int *)kp->arg;
 101
 102	switch (*ip)
 103	{
 104	case SVC_POOL_AUTO:
 105		return strlcpy(buf, "auto", 20);
 106	case SVC_POOL_GLOBAL:
 107		return strlcpy(buf, "global", 20);
 108	case SVC_POOL_PERCPU:
 109		return strlcpy(buf, "percpu", 20);
 110	case SVC_POOL_PERNODE:
 111		return strlcpy(buf, "pernode", 20);
 112	default:
 113		return sprintf(buf, "%d", *ip);
 114	}
 115}
 116
 117module_param_call(pool_mode, param_set_pool_mode, param_get_pool_mode,
 118		 &svc_pool_map.mode, 0644);
 119
 120/*
 121 * Detect best pool mapping mode heuristically,
 122 * according to the machine's topology.
 123 */
 124static int
 125svc_pool_map_choose_mode(void)
 126{
 127	unsigned int node;
 128
 129	if (nr_online_nodes > 1) {
 130		/*
 131		 * Actually have multiple NUMA nodes,
 132		 * so split pools on NUMA node boundaries
 133		 */
 134		return SVC_POOL_PERNODE;
 135	}
 136
 137	node = first_online_node;
 138	if (nr_cpus_node(node) > 2) {
 139		/*
 140		 * Non-trivial SMP, or CONFIG_NUMA on
 141		 * non-NUMA hardware, e.g. with a generic
 142		 * x86_64 kernel on Xeons.  In this case we
 143		 * want to divide the pools on cpu boundaries.
 144		 */
 145		return SVC_POOL_PERCPU;
 146	}
 147
 148	/* default: one global pool */
 149	return SVC_POOL_GLOBAL;
 150}
 151
 152/*
 153 * Allocate the to_pool[] and pool_to[] arrays.
 154 * Returns 0 on success or an errno.
 155 */
 156static int
 157svc_pool_map_alloc_arrays(struct svc_pool_map *m, unsigned int maxpools)
 158{
 159	m->to_pool = kcalloc(maxpools, sizeof(unsigned int), GFP_KERNEL);
 160	if (!m->to_pool)
 161		goto fail;
 162	m->pool_to = kcalloc(maxpools, sizeof(unsigned int), GFP_KERNEL);
 163	if (!m->pool_to)
 164		goto fail_free;
 165
 166	return 0;
 167
 168fail_free:
 169	kfree(m->to_pool);
 
 170fail:
 171	return -ENOMEM;
 172}
 173
 174/*
 175 * Initialise the pool map for SVC_POOL_PERCPU mode.
 176 * Returns number of pools or <0 on error.
 177 */
 178static int
 179svc_pool_map_init_percpu(struct svc_pool_map *m)
 180{
 181	unsigned int maxpools = nr_cpu_ids;
 182	unsigned int pidx = 0;
 183	unsigned int cpu;
 184	int err;
 185
 186	err = svc_pool_map_alloc_arrays(m, maxpools);
 187	if (err)
 188		return err;
 189
 190	for_each_online_cpu(cpu) {
 191		BUG_ON(pidx > maxpools);
 192		m->to_pool[cpu] = pidx;
 193		m->pool_to[pidx] = cpu;
 194		pidx++;
 195	}
 196	/* cpus brought online later all get mapped to pool0, sorry */
 197
 198	return pidx;
 199};
 200
 201
 202/*
 203 * Initialise the pool map for SVC_POOL_PERNODE mode.
 204 * Returns number of pools or <0 on error.
 205 */
 206static int
 207svc_pool_map_init_pernode(struct svc_pool_map *m)
 208{
 209	unsigned int maxpools = nr_node_ids;
 210	unsigned int pidx = 0;
 211	unsigned int node;
 212	int err;
 213
 214	err = svc_pool_map_alloc_arrays(m, maxpools);
 215	if (err)
 216		return err;
 217
 218	for_each_node_with_cpus(node) {
 219		/* some architectures (e.g. SN2) have cpuless nodes */
 220		BUG_ON(pidx > maxpools);
 221		m->to_pool[node] = pidx;
 222		m->pool_to[pidx] = node;
 223		pidx++;
 224	}
 225	/* nodes brought online later all get mapped to pool0, sorry */
 226
 227	return pidx;
 228}
 229
 230
 231/*
 232 * Add a reference to the global map of cpus to pools (and
 233 * vice versa).  Initialise the map if we're the first user.
 234 * Returns the number of pools.
 235 */
 236static unsigned int
 237svc_pool_map_get(void)
 238{
 239	struct svc_pool_map *m = &svc_pool_map;
 240	int npools = -1;
 241
 242	mutex_lock(&svc_pool_map_mutex);
 243
 244	if (m->count++) {
 245		mutex_unlock(&svc_pool_map_mutex);
 246		return m->npools;
 247	}
 248
 249	if (m->mode == SVC_POOL_AUTO)
 250		m->mode = svc_pool_map_choose_mode();
 251
 252	switch (m->mode) {
 253	case SVC_POOL_PERCPU:
 254		npools = svc_pool_map_init_percpu(m);
 255		break;
 256	case SVC_POOL_PERNODE:
 257		npools = svc_pool_map_init_pernode(m);
 258		break;
 259	}
 260
 261	if (npools < 0) {
 262		/* default, or memory allocation failure */
 263		npools = 1;
 264		m->mode = SVC_POOL_GLOBAL;
 265	}
 266	m->npools = npools;
 267
 268	mutex_unlock(&svc_pool_map_mutex);
 269	return m->npools;
 270}
 271
 272
 273/*
 274 * Drop a reference to the global map of cpus to pools.
 275 * When the last reference is dropped, the map data is
 276 * freed; this allows the sysadmin to change the pool
 277 * mode using the pool_mode module option without
 278 * rebooting or re-loading sunrpc.ko.
 279 */
 280static void
 281svc_pool_map_put(void)
 282{
 283	struct svc_pool_map *m = &svc_pool_map;
 284
 285	mutex_lock(&svc_pool_map_mutex);
 286
 287	if (!--m->count) {
 288		m->mode = SVC_POOL_DEFAULT;
 289		kfree(m->to_pool);
 
 290		kfree(m->pool_to);
 
 291		m->npools = 0;
 292	}
 293
 294	mutex_unlock(&svc_pool_map_mutex);
 295}
 
 296
 
 
 
 297
 
 
 
 
 
 
 
 
 298/*
 299 * Set the given thread's cpus_allowed mask so that it
 300 * will only run on cpus in the given pool.
 301 */
 302static inline void
 303svc_pool_map_set_cpumask(struct task_struct *task, unsigned int pidx)
 304{
 305	struct svc_pool_map *m = &svc_pool_map;
 306	unsigned int node = m->pool_to[pidx];
 307
 308	/*
 309	 * The caller checks for sv_nrpools > 1, which
 310	 * implies that we've been initialized.
 311	 */
 312	BUG_ON(m->count == 0);
 
 
 313
 314	switch (m->mode) {
 315	case SVC_POOL_PERCPU:
 316	{
 317		set_cpus_allowed_ptr(task, cpumask_of(node));
 318		break;
 319	}
 320	case SVC_POOL_PERNODE:
 321	{
 322		set_cpus_allowed_ptr(task, cpumask_of_node(node));
 323		break;
 324	}
 325	}
 326}
 327
 328/*
 329 * Use the mapping mode to choose a pool for a given CPU.
 330 * Used when enqueueing an incoming RPC.  Always returns
 331 * a non-NULL pool pointer.
 332 */
 333struct svc_pool *
 334svc_pool_for_cpu(struct svc_serv *serv, int cpu)
 335{
 336	struct svc_pool_map *m = &svc_pool_map;
 337	unsigned int pidx = 0;
 338
 339	/*
 340	 * An uninitialised map happens in a pure client when
 341	 * lockd is brought up, so silently treat it the
 342	 * same as SVC_POOL_GLOBAL.
 343	 */
 344	if (svc_serv_is_pooled(serv)) {
 345		switch (m->mode) {
 346		case SVC_POOL_PERCPU:
 347			pidx = m->to_pool[cpu];
 348			break;
 349		case SVC_POOL_PERNODE:
 350			pidx = m->to_pool[cpu_to_node(cpu)];
 351			break;
 352		}
 353	}
 354	return &serv->sv_pools[pidx % serv->sv_nrpools];
 355}
 356
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 357
 358/*
 359 * Create an RPC service
 360 */
 361static struct svc_serv *
 362__svc_create(struct svc_program *prog, unsigned int bufsize, int npools,
 363	     void (*shutdown)(struct svc_serv *serv))
 364{
 365	struct svc_serv	*serv;
 366	unsigned int vers;
 367	unsigned int xdrsize;
 368	unsigned int i;
 369
 370	if (!(serv = kzalloc(sizeof(*serv), GFP_KERNEL)))
 371		return NULL;
 372	serv->sv_name      = prog->pg_name;
 373	serv->sv_program   = prog;
 374	serv->sv_nrthreads = 1;
 375	serv->sv_stats     = prog->pg_stats;
 376	if (bufsize > RPCSVC_MAXPAYLOAD)
 377		bufsize = RPCSVC_MAXPAYLOAD;
 378	serv->sv_max_payload = bufsize? bufsize : 4096;
 379	serv->sv_max_mesg  = roundup(serv->sv_max_payload + PAGE_SIZE, PAGE_SIZE);
 380	serv->sv_shutdown  = shutdown;
 381	xdrsize = 0;
 382	while (prog) {
 383		prog->pg_lovers = prog->pg_nvers-1;
 384		for (vers=0; vers<prog->pg_nvers ; vers++)
 385			if (prog->pg_vers[vers]) {
 386				prog->pg_hivers = vers;
 387				if (prog->pg_lovers > vers)
 388					prog->pg_lovers = vers;
 389				if (prog->pg_vers[vers]->vs_xdrsize > xdrsize)
 390					xdrsize = prog->pg_vers[vers]->vs_xdrsize;
 391			}
 392		prog = prog->pg_next;
 393	}
 394	serv->sv_xdrsize   = xdrsize;
 395	INIT_LIST_HEAD(&serv->sv_tempsocks);
 396	INIT_LIST_HEAD(&serv->sv_permsocks);
 397	init_timer(&serv->sv_temptimer);
 398	spin_lock_init(&serv->sv_lock);
 399
 400	serv->sv_nrpools = npools;
 401	serv->sv_pools =
 402		kcalloc(serv->sv_nrpools, sizeof(struct svc_pool),
 403			GFP_KERNEL);
 404	if (!serv->sv_pools) {
 405		kfree(serv);
 406		return NULL;
 407	}
 408
 409	for (i = 0; i < serv->sv_nrpools; i++) {
 410		struct svc_pool *pool = &serv->sv_pools[i];
 411
 412		dprintk("svc: initialising pool %u for %s\n",
 413				i, serv->sv_name);
 414
 415		pool->sp_id = i;
 416		INIT_LIST_HEAD(&pool->sp_threads);
 417		INIT_LIST_HEAD(&pool->sp_sockets);
 418		INIT_LIST_HEAD(&pool->sp_all_threads);
 419		spin_lock_init(&pool->sp_lock);
 420	}
 421
 422	/* Remove any stale portmap registrations */
 423	svc_unregister(serv);
 424
 425	return serv;
 426}
 427
 428struct svc_serv *
 429svc_create(struct svc_program *prog, unsigned int bufsize,
 430	   void (*shutdown)(struct svc_serv *serv))
 431{
 432	return __svc_create(prog, bufsize, /*npools*/1, shutdown);
 433}
 434EXPORT_SYMBOL_GPL(svc_create);
 435
 436struct svc_serv *
 437svc_create_pooled(struct svc_program *prog, unsigned int bufsize,
 438		  void (*shutdown)(struct svc_serv *serv),
 439		  svc_thread_fn func, struct module *mod)
 440{
 441	struct svc_serv *serv;
 442	unsigned int npools = svc_pool_map_get();
 443
 444	serv = __svc_create(prog, bufsize, npools, shutdown);
 
 
 
 
 
 
 
 
 445
 446	if (serv != NULL) {
 447		serv->sv_function = func;
 448		serv->sv_module = mod;
 449	}
 450
 451	return serv;
 
 452}
 453EXPORT_SYMBOL_GPL(svc_create_pooled);
 454
 455/*
 456 * Destroy an RPC service. Should be called with appropriate locking to
 457 * protect the sv_nrthreads, sv_permsocks and sv_tempsocks.
 458 */
 459void
 460svc_destroy(struct svc_serv *serv)
 461{
 462	dprintk("svc: svc_destroy(%s, %d)\n",
 463				serv->sv_program->pg_name,
 464				serv->sv_nrthreads);
 465
 466	if (serv->sv_nrthreads) {
 467		if (--(serv->sv_nrthreads) != 0) {
 468			svc_sock_update_bufs(serv);
 469			return;
 470		}
 471	} else
 472		printk("svc_destroy: no threads for serv=%p!\n", serv);
 473
 474	del_timer_sync(&serv->sv_temptimer);
 475
 476	svc_close_all(&serv->sv_tempsocks);
 477
 478	if (serv->sv_shutdown)
 479		serv->sv_shutdown(serv);
 480
 481	svc_close_all(&serv->sv_permsocks);
 482
 483	BUG_ON(!list_empty(&serv->sv_permsocks));
 484	BUG_ON(!list_empty(&serv->sv_tempsocks));
 485
 486	cache_clean_deferred(serv);
 487
 488	if (svc_serv_is_pooled(serv))
 489		svc_pool_map_put();
 490
 491	svc_unregister(serv);
 492	kfree(serv->sv_pools);
 493	kfree(serv);
 494}
 495EXPORT_SYMBOL_GPL(svc_destroy);
 496
 497/*
 498 * Allocate an RPC server's buffer space.
 499 * We allocate pages and place them in rq_argpages.
 500 */
 501static int
 502svc_init_buffer(struct svc_rqst *rqstp, unsigned int size)
 503{
 504	unsigned int pages, arghi;
 505
 506	/* bc_xprt uses fore channel allocated buffers */
 507	if (svc_is_backchannel(rqstp))
 508		return 1;
 509
 510	pages = size / PAGE_SIZE + 1; /* extra page as we hold both request and reply.
 511				       * We assume one is at most one page
 512				       */
 513	arghi = 0;
 514	BUG_ON(pages > RPCSVC_MAXPAGES);
 
 
 515	while (pages) {
 516		struct page *p = alloc_page(GFP_KERNEL);
 517		if (!p)
 518			break;
 519		rqstp->rq_pages[arghi++] = p;
 520		pages--;
 521	}
 522	return pages == 0;
 523}
 524
 525/*
 526 * Release an RPC server buffer
 527 */
 528static void
 529svc_release_buffer(struct svc_rqst *rqstp)
 530{
 531	unsigned int i;
 532
 533	for (i = 0; i < ARRAY_SIZE(rqstp->rq_pages); i++)
 534		if (rqstp->rq_pages[i])
 535			put_page(rqstp->rq_pages[i]);
 536}
 537
 538struct svc_rqst *
 539svc_prepare_thread(struct svc_serv *serv, struct svc_pool *pool)
 540{
 541	struct svc_rqst	*rqstp;
 542
 543	rqstp = kzalloc(sizeof(*rqstp), GFP_KERNEL);
 544	if (!rqstp)
 545		goto out_enomem;
 546
 547	init_waitqueue_head(&rqstp->rq_wait);
 548
 549	serv->sv_nrthreads++;
 550	spin_lock_bh(&pool->sp_lock);
 551	pool->sp_nrthreads++;
 552	list_add(&rqstp->rq_all, &pool->sp_all_threads);
 553	spin_unlock_bh(&pool->sp_lock);
 554	rqstp->rq_server = serv;
 555	rqstp->rq_pool = pool;
 556
 557	rqstp->rq_argp = kmalloc(serv->sv_xdrsize, GFP_KERNEL);
 558	if (!rqstp->rq_argp)
 559		goto out_thread;
 560
 561	rqstp->rq_resp = kmalloc(serv->sv_xdrsize, GFP_KERNEL);
 562	if (!rqstp->rq_resp)
 563		goto out_thread;
 564
 565	if (!svc_init_buffer(rqstp, serv->sv_max_mesg))
 566		goto out_thread;
 567
 568	return rqstp;
 569out_thread:
 570	svc_exit_thread(rqstp);
 571out_enomem:
 572	return ERR_PTR(-ENOMEM);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 573}
 574EXPORT_SYMBOL_GPL(svc_prepare_thread);
 575
 576/*
 577 * Choose a pool in which to create a new thread, for svc_set_num_threads
 578 */
 579static inline struct svc_pool *
 580choose_pool(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)
 581{
 582	if (pool != NULL)
 583		return pool;
 584
 585	return &serv->sv_pools[(*state)++ % serv->sv_nrpools];
 586}
 587
 588/*
 589 * Choose a thread to kill, for svc_set_num_threads
 590 */
 591static inline struct task_struct *
 592choose_victim(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)
 593{
 594	unsigned int i;
 595	struct task_struct *task = NULL;
 596
 597	if (pool != NULL) {
 598		spin_lock_bh(&pool->sp_lock);
 599	} else {
 600		/* choose a pool in round-robin fashion */
 601		for (i = 0; i < serv->sv_nrpools; i++) {
 602			pool = &serv->sv_pools[--(*state) % serv->sv_nrpools];
 603			spin_lock_bh(&pool->sp_lock);
 604			if (!list_empty(&pool->sp_all_threads))
 605				goto found_pool;
 606			spin_unlock_bh(&pool->sp_lock);
 607		}
 608		return NULL;
 609	}
 610
 611found_pool:
 612	if (!list_empty(&pool->sp_all_threads)) {
 613		struct svc_rqst *rqstp;
 614
 615		/*
 616		 * Remove from the pool->sp_all_threads list
 617		 * so we don't try to kill it again.
 618		 */
 619		rqstp = list_entry(pool->sp_all_threads.next, struct svc_rqst, rq_all);
 620		list_del_init(&rqstp->rq_all);
 
 621		task = rqstp->rq_task;
 622	}
 623	spin_unlock_bh(&pool->sp_lock);
 624
 625	return task;
 626}
 627
 628/*
 629 * Create or destroy enough new threads to make the number
 630 * of threads the given number.  If `pool' is non-NULL, applies
 631 * only to threads in that pool, otherwise round-robins between
 632 * all pools.  Must be called with a svc_get() reference and
 633 * the BKL or another lock to protect access to svc_serv fields.
 634 *
 635 * Destroying threads relies on the service threads filling in
 636 * rqstp->rq_task, which only the nfs ones do.  Assumes the serv
 637 * has been created using svc_create_pooled().
 638 *
 639 * Based on code that used to be in nfsd_svc() but tweaked
 640 * to be pool-aware.
 641 */
 642int
 643svc_set_num_threads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
 644{
 645	struct svc_rqst	*rqstp;
 646	struct task_struct *task;
 647	struct svc_pool *chosen_pool;
 648	int error = 0;
 649	unsigned int state = serv->sv_nrthreads-1;
 
 650
 651	if (pool == NULL) {
 652		/* The -1 assumes caller has done a svc_get() */
 653		nrservs -= (serv->sv_nrthreads-1);
 654	} else {
 655		spin_lock_bh(&pool->sp_lock);
 656		nrservs -= pool->sp_nrthreads;
 657		spin_unlock_bh(&pool->sp_lock);
 658	}
 659
 660	/* create new threads */
 661	while (nrservs > 0) {
 662		nrservs--;
 663		chosen_pool = choose_pool(serv, pool, &state);
 664
 665		rqstp = svc_prepare_thread(serv, chosen_pool);
 
 666		if (IS_ERR(rqstp)) {
 667			error = PTR_ERR(rqstp);
 668			break;
 669		}
 670
 671		__module_get(serv->sv_module);
 672		task = kthread_create(serv->sv_function, rqstp, serv->sv_name);
 
 673		if (IS_ERR(task)) {
 674			error = PTR_ERR(task);
 675			module_put(serv->sv_module);
 676			svc_exit_thread(rqstp);
 677			break;
 678		}
 679
 680		rqstp->rq_task = task;
 681		if (serv->sv_nrpools > 1)
 682			svc_pool_map_set_cpumask(task, chosen_pool->sp_id);
 683
 684		svc_sock_update_bufs(serv);
 685		wake_up_process(task);
 686	}
 687	/* destroy old threads */
 688	while (nrservs < 0 &&
 689	       (task = choose_victim(serv, pool, &state)) != NULL) {
 690		send_sig(SIGINT, task, 1);
 691		nrservs++;
 692	}
 693
 694	return error;
 695}
 696EXPORT_SYMBOL_GPL(svc_set_num_threads);
 697
 698/*
 699 * Called from a server thread as it's exiting. Caller must hold the BKL or
 700 * the "service mutex", whichever is appropriate for the service.
 701 */
 702void
 703svc_exit_thread(struct svc_rqst *rqstp)
 704{
 705	struct svc_serv	*serv = rqstp->rq_server;
 706	struct svc_pool	*pool = rqstp->rq_pool;
 707
 708	svc_release_buffer(rqstp);
 709	kfree(rqstp->rq_resp);
 710	kfree(rqstp->rq_argp);
 711	kfree(rqstp->rq_auth_data);
 
 
 
 
 
 
 
 
 
 712
 713	spin_lock_bh(&pool->sp_lock);
 714	pool->sp_nrthreads--;
 715	list_del(&rqstp->rq_all);
 
 716	spin_unlock_bh(&pool->sp_lock);
 717
 718	kfree(rqstp);
 719
 720	/* Release the server */
 721	if (serv)
 722		svc_destroy(serv);
 723}
 724EXPORT_SYMBOL_GPL(svc_exit_thread);
 725
 726/*
 727 * Register an "inet" protocol family netid with the local
 728 * rpcbind daemon via an rpcbind v4 SET request.
 729 *
 730 * No netconfig infrastructure is available in the kernel, so
 731 * we map IP_ protocol numbers to netids by hand.
 732 *
 733 * Returns zero on success; a negative errno value is returned
 734 * if any error occurs.
 735 */
 736static int __svc_rpcb_register4(const u32 program, const u32 version,
 
 737				const unsigned short protocol,
 738				const unsigned short port)
 739{
 740	const struct sockaddr_in sin = {
 741		.sin_family		= AF_INET,
 742		.sin_addr.s_addr	= htonl(INADDR_ANY),
 743		.sin_port		= htons(port),
 744	};
 745	const char *netid;
 746	int error;
 747
 748	switch (protocol) {
 749	case IPPROTO_UDP:
 750		netid = RPCBIND_NETID_UDP;
 751		break;
 752	case IPPROTO_TCP:
 753		netid = RPCBIND_NETID_TCP;
 754		break;
 755	default:
 756		return -ENOPROTOOPT;
 757	}
 758
 759	error = rpcb_v4_register(program, version,
 760					(const struct sockaddr *)&sin, netid);
 761
 762	/*
 763	 * User space didn't support rpcbind v4, so retry this
 764	 * registration request with the legacy rpcbind v2 protocol.
 765	 */
 766	if (error == -EPROTONOSUPPORT)
 767		error = rpcb_register(program, version, protocol, port);
 768
 769	return error;
 770}
 771
 772#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 773/*
 774 * Register an "inet6" protocol family netid with the local
 775 * rpcbind daemon via an rpcbind v4 SET request.
 776 *
 777 * No netconfig infrastructure is available in the kernel, so
 778 * we map IP_ protocol numbers to netids by hand.
 779 *
 780 * Returns zero on success; a negative errno value is returned
 781 * if any error occurs.
 782 */
 783static int __svc_rpcb_register6(const u32 program, const u32 version,
 
 784				const unsigned short protocol,
 785				const unsigned short port)
 786{
 787	const struct sockaddr_in6 sin6 = {
 788		.sin6_family		= AF_INET6,
 789		.sin6_addr		= IN6ADDR_ANY_INIT,
 790		.sin6_port		= htons(port),
 791	};
 792	const char *netid;
 793	int error;
 794
 795	switch (protocol) {
 796	case IPPROTO_UDP:
 797		netid = RPCBIND_NETID_UDP6;
 798		break;
 799	case IPPROTO_TCP:
 800		netid = RPCBIND_NETID_TCP6;
 801		break;
 802	default:
 803		return -ENOPROTOOPT;
 804	}
 805
 806	error = rpcb_v4_register(program, version,
 807					(const struct sockaddr *)&sin6, netid);
 808
 809	/*
 810	 * User space didn't support rpcbind version 4, so we won't
 811	 * use a PF_INET6 listener.
 812	 */
 813	if (error == -EPROTONOSUPPORT)
 814		error = -EAFNOSUPPORT;
 815
 816	return error;
 817}
 818#endif	/* defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) */
 819
 820/*
 821 * Register a kernel RPC service via rpcbind version 4.
 822 *
 823 * Returns zero on success; a negative errno value is returned
 824 * if any error occurs.
 825 */
 826static int __svc_register(const char *progname,
 827			  const u32 program, const u32 version,
 828			  const int family,
 829			  const unsigned short protocol,
 830			  const unsigned short port)
 831{
 832	int error = -EAFNOSUPPORT;
 833
 834	switch (family) {
 835	case PF_INET:
 836		error = __svc_rpcb_register4(program, version,
 837						protocol, port);
 838		break;
 839#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 840	case PF_INET6:
 841		error = __svc_rpcb_register6(program, version,
 842						protocol, port);
 843#endif	/* defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) */
 844	}
 845
 846	if (error < 0)
 847		printk(KERN_WARNING "svc: failed to register %sv%u RPC "
 848			"service (errno %d).\n", progname, version, -error);
 849	return error;
 850}
 851
 852/**
 853 * svc_register - register an RPC service with the local portmapper
 854 * @serv: svc_serv struct for the service to register
 
 855 * @family: protocol family of service's listener socket
 856 * @proto: transport protocol number to advertise
 857 * @port: port to advertise
 858 *
 859 * Service is registered for any address in the passed-in protocol family
 860 */
 861int svc_register(const struct svc_serv *serv, const int family,
 862		 const unsigned short proto, const unsigned short port)
 
 863{
 864	struct svc_program	*progp;
 
 865	unsigned int		i;
 866	int			error = 0;
 867
 868	BUG_ON(proto == 0 && port == 0);
 
 
 869
 870	for (progp = serv->sv_program; progp; progp = progp->pg_next) {
 871		for (i = 0; i < progp->pg_nvers; i++) {
 872			if (progp->pg_vers[i] == NULL)
 
 873				continue;
 874
 875			dprintk("svc: svc_register(%sv%d, %s, %u, %u)%s\n",
 876					progp->pg_name,
 877					i,
 878					proto == IPPROTO_UDP?  "udp" : "tcp",
 879					port,
 880					family,
 881					progp->pg_vers[i]->vs_hidden?
 882						" (but not telling portmap)" : "");
 883
 884			if (progp->pg_vers[i]->vs_hidden)
 885				continue;
 886
 887			error = __svc_register(progp->pg_name, progp->pg_prog,
 888						i, family, proto, port);
 889			if (error < 0)
 
 
 
 
 
 
 
 
 
 890				break;
 
 891		}
 892	}
 893
 894	return error;
 895}
 896
 897/*
 898 * If user space is running rpcbind, it should take the v4 UNSET
 899 * and clear everything for this [program, version].  If user space
 900 * is running portmap, it will reject the v4 UNSET, but won't have
 901 * any "inet6" entries anyway.  So a PMAP_UNSET should be sufficient
 902 * in this case to clear all existing entries for [program, version].
 903 */
 904static void __svc_unregister(const u32 program, const u32 version,
 905			     const char *progname)
 906{
 907	int error;
 908
 909	error = rpcb_v4_register(program, version, NULL, "");
 910
 911	/*
 912	 * User space didn't support rpcbind v4, so retry this
 913	 * request with the legacy rpcbind v2 protocol.
 914	 */
 915	if (error == -EPROTONOSUPPORT)
 916		error = rpcb_register(program, version, 0, 0);
 917
 918	dprintk("svc: %s(%sv%u), error %d\n",
 919			__func__, progname, version, error);
 920}
 921
 922/*
 923 * All netids, bind addresses and ports registered for [program, version]
 924 * are removed from the local rpcbind database (if the service is not
 925 * hidden) to make way for a new instance of the service.
 926 *
 927 * The result of unregistration is reported via dprintk for those who want
 928 * verification of the result, but is otherwise not important.
 929 */
 930static void svc_unregister(const struct svc_serv *serv)
 931{
 932	struct svc_program *progp;
 933	unsigned long flags;
 934	unsigned int i;
 935
 936	clear_thread_flag(TIF_SIGPENDING);
 937
 938	for (progp = serv->sv_program; progp; progp = progp->pg_next) {
 939		for (i = 0; i < progp->pg_nvers; i++) {
 940			if (progp->pg_vers[i] == NULL)
 941				continue;
 942			if (progp->pg_vers[i]->vs_hidden)
 943				continue;
 944
 945			dprintk("svc: attempting to unregister %sv%u\n",
 946				progp->pg_name, i);
 947			__svc_unregister(progp->pg_prog, i, progp->pg_name);
 948		}
 949	}
 950
 951	spin_lock_irqsave(&current->sighand->siglock, flags);
 952	recalc_sigpending();
 953	spin_unlock_irqrestore(&current->sighand->siglock, flags);
 954}
 955
 956/*
 957 * Printk the given error with the address of the client that caused it.
 958 */
 959static int
 960__attribute__ ((format (printf, 2, 3)))
 961svc_printk(struct svc_rqst *rqstp, const char *fmt, ...)
 962{
 
 963	va_list args;
 964	int 	r;
 965	char 	buf[RPC_MAX_ADDRBUFLEN];
 966
 967	if (!net_ratelimit())
 968		return 0;
 
 
 969
 970	printk(KERN_WARNING "svc: %s: ",
 971		svc_print_addr(rqstp, buf, sizeof(buf)));
 972
 973	va_start(args, fmt);
 974	r = vprintk(fmt, args);
 975	va_end(args);
 976
 977	return r;
 978}
 
 
 
 979
 980/*
 981 * Common routine for processing the RPC request.
 982 */
 983static int
 984svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
 985{
 986	struct svc_program	*progp;
 987	struct svc_version	*versp = NULL;	/* compiler food */
 988	struct svc_procedure	*procp = NULL;
 989	struct svc_serv		*serv = rqstp->rq_server;
 990	kxdrproc_t		xdr;
 991	__be32			*statp;
 992	u32			prog, vers, proc;
 993	__be32			auth_stat, rpc_stat;
 994	int			auth_res;
 995	__be32			*reply_statp;
 996
 997	rpc_stat = rpc_success;
 998
 999	if (argv->iov_len < 6*4)
1000		goto err_short_len;
1001
1002	/* Will be turned off only in gss privacy case: */
1003	rqstp->rq_splice_ok = 1;
1004	/* Will be turned off only when NFSv4 Sessions are used */
1005	rqstp->rq_usedeferral = 1;
1006	rqstp->rq_dropme = false;
1007
1008	/* Setup reply header */
1009	rqstp->rq_xprt->xpt_ops->xpo_prep_reply_hdr(rqstp);
1010
1011	svc_putu32(resv, rqstp->rq_xid);
1012
1013	vers = svc_getnl(argv);
1014
1015	/* First words of reply: */
1016	svc_putnl(resv, 1);		/* REPLY */
1017
1018	if (vers != 2)		/* RPC version number */
1019		goto err_bad_rpc;
1020
1021	/* Save position in case we later decide to reject: */
1022	reply_statp = resv->iov_base + resv->iov_len;
1023
1024	svc_putnl(resv, 0);		/* ACCEPT */
1025
1026	rqstp->rq_prog = prog = svc_getnl(argv);	/* program number */
1027	rqstp->rq_vers = vers = svc_getnl(argv);	/* version number */
1028	rqstp->rq_proc = proc = svc_getnl(argv);	/* procedure number */
1029
1030	progp = serv->sv_program;
1031
1032	for (progp = serv->sv_program; progp; progp = progp->pg_next)
1033		if (prog == progp->pg_prog)
1034			break;
1035
1036	/*
1037	 * Decode auth data, and add verifier to reply buffer.
1038	 * We do this before anything else in order to get a decent
1039	 * auth verifier.
1040	 */
1041	auth_res = svc_authenticate(rqstp, &auth_stat);
1042	/* Also give the program a chance to reject this call: */
1043	if (auth_res == SVC_OK && progp) {
1044		auth_stat = rpc_autherr_badcred;
1045		auth_res = progp->pg_authenticate(rqstp);
1046	}
1047	switch (auth_res) {
1048	case SVC_OK:
1049		break;
1050	case SVC_GARBAGE:
1051		goto err_garbage;
1052	case SVC_SYSERR:
1053		rpc_stat = rpc_system_err;
1054		goto err_bad;
1055	case SVC_DENIED:
1056		goto err_bad_auth;
1057	case SVC_CLOSE:
1058		if (test_bit(XPT_TEMP, &rqstp->rq_xprt->xpt_flags))
1059			svc_close_xprt(rqstp->rq_xprt);
1060	case SVC_DROP:
1061		goto dropit;
1062	case SVC_COMPLETE:
1063		goto sendit;
1064	}
1065
1066	if (progp == NULL)
1067		goto err_bad_prog;
1068
1069	if (vers >= progp->pg_nvers ||
1070	  !(versp = progp->pg_vers[vers]))
1071		goto err_bad_vers;
1072
1073	procp = versp->vs_proc + proc;
1074	if (proc >= versp->vs_nproc || !procp->pc_func)
1075		goto err_bad_proc;
1076	rqstp->rq_procinfo = procp;
1077
1078	/* Syntactic check complete */
1079	serv->sv_stats->rpccnt++;
1080
1081	/* Build the reply header. */
1082	statp = resv->iov_base +resv->iov_len;
1083	svc_putnl(resv, RPC_SUCCESS);
1084
1085	/* Bump per-procedure stats counter */
1086	procp->pc_count++;
1087
1088	/* Initialize storage for argp and resp */
1089	memset(rqstp->rq_argp, 0, procp->pc_argsize);
1090	memset(rqstp->rq_resp, 0, procp->pc_ressize);
1091
1092	/* un-reserve some of the out-queue now that we have a
1093	 * better idea of reply size
1094	 */
1095	if (procp->pc_xdrressize)
1096		svc_reserve_auth(rqstp, procp->pc_xdrressize<<2);
1097
1098	/* Call the function that processes the request. */
1099	if (!versp->vs_dispatch) {
1100		/* Decode arguments */
1101		xdr = procp->pc_decode;
1102		if (xdr && !xdr(rqstp, argv->iov_base, rqstp->rq_argp))
1103			goto err_garbage;
1104
1105		*statp = procp->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
1106
1107		/* Encode reply */
1108		if (rqstp->rq_dropme) {
1109			if (procp->pc_release)
1110				procp->pc_release(rqstp, NULL, rqstp->rq_resp);
1111			goto dropit;
1112		}
1113		if (*statp == rpc_success &&
1114		    (xdr = procp->pc_encode) &&
1115		    !xdr(rqstp, resv->iov_base+resv->iov_len, rqstp->rq_resp)) {
1116			dprintk("svc: failed to encode reply\n");
1117			/* serv->sv_stats->rpcsystemerr++; */
1118			*statp = rpc_system_err;
1119		}
1120	} else {
1121		dprintk("svc: calling dispatcher\n");
1122		if (!versp->vs_dispatch(rqstp, statp)) {
1123			/* Release reply info */
1124			if (procp->pc_release)
1125				procp->pc_release(rqstp, NULL, rqstp->rq_resp);
1126			goto dropit;
1127		}
1128	}
1129
1130	/* Check RPC status result */
1131	if (*statp != rpc_success)
1132		resv->iov_len = ((void*)statp)  - resv->iov_base + 4;
1133
1134	/* Release reply info */
1135	if (procp->pc_release)
1136		procp->pc_release(rqstp, NULL, rqstp->rq_resp);
1137
1138	if (procp->pc_encode == NULL)
1139		goto dropit;
1140
1141 sendit:
1142	if (svc_authorise(rqstp))
1143		goto dropit;
1144	return 1;		/* Caller can now send it */
1145
1146 dropit:
1147	svc_authorise(rqstp);	/* doesn't hurt to call this twice */
1148	dprintk("svc: svc_process dropit\n");
1149	return 0;
1150
1151err_short_len:
1152	svc_printk(rqstp, "short len %Zd, dropping request\n",
1153			argv->iov_len);
1154
1155	goto dropit;			/* drop request */
1156
1157err_bad_rpc:
1158	serv->sv_stats->rpcbadfmt++;
1159	svc_putnl(resv, 1);	/* REJECT */
1160	svc_putnl(resv, 0);	/* RPC_MISMATCH */
1161	svc_putnl(resv, 2);	/* Only RPCv2 supported */
1162	svc_putnl(resv, 2);
1163	goto sendit;
1164
1165err_bad_auth:
1166	dprintk("svc: authentication failed (%d)\n", ntohl(auth_stat));
1167	serv->sv_stats->rpcbadauth++;
1168	/* Restore write pointer to location of accept status: */
1169	xdr_ressize_check(rqstp, reply_statp);
1170	svc_putnl(resv, 1);	/* REJECT */
1171	svc_putnl(resv, 1);	/* AUTH_ERROR */
1172	svc_putnl(resv, ntohl(auth_stat));	/* status */
1173	goto sendit;
1174
1175err_bad_prog:
1176	dprintk("svc: unknown program %d\n", prog);
1177	serv->sv_stats->rpcbadfmt++;
1178	svc_putnl(resv, RPC_PROG_UNAVAIL);
1179	goto sendit;
1180
1181err_bad_vers:
1182	svc_printk(rqstp, "unknown version (%d for prog %d, %s)\n",
1183		       vers, prog, progp->pg_name);
1184
1185	serv->sv_stats->rpcbadfmt++;
1186	svc_putnl(resv, RPC_PROG_MISMATCH);
1187	svc_putnl(resv, progp->pg_lovers);
1188	svc_putnl(resv, progp->pg_hivers);
1189	goto sendit;
1190
1191err_bad_proc:
1192	svc_printk(rqstp, "unknown procedure (%d)\n", proc);
1193
1194	serv->sv_stats->rpcbadfmt++;
1195	svc_putnl(resv, RPC_PROC_UNAVAIL);
1196	goto sendit;
1197
1198err_garbage:
1199	svc_printk(rqstp, "failed to decode args\n");
1200
1201	rpc_stat = rpc_garbage_args;
1202err_bad:
1203	serv->sv_stats->rpcbadfmt++;
1204	svc_putnl(resv, ntohl(rpc_stat));
1205	goto sendit;
1206}
1207EXPORT_SYMBOL_GPL(svc_process);
1208
1209/*
1210 * Process the RPC request.
1211 */
1212int
1213svc_process(struct svc_rqst *rqstp)
1214{
1215	struct kvec		*argv = &rqstp->rq_arg.head[0];
1216	struct kvec		*resv = &rqstp->rq_res.head[0];
1217	struct svc_serv		*serv = rqstp->rq_server;
1218	u32			dir;
1219
1220	/*
1221	 * Setup response xdr_buf.
1222	 * Initially it has just one page
1223	 */
1224	rqstp->rq_resused = 1;
1225	resv->iov_base = page_address(rqstp->rq_respages[0]);
1226	resv->iov_len = 0;
1227	rqstp->rq_res.pages = rqstp->rq_respages + 1;
1228	rqstp->rq_res.len = 0;
1229	rqstp->rq_res.page_base = 0;
1230	rqstp->rq_res.page_len = 0;
1231	rqstp->rq_res.buflen = PAGE_SIZE;
1232	rqstp->rq_res.tail[0].iov_base = NULL;
1233	rqstp->rq_res.tail[0].iov_len = 0;
1234
1235	rqstp->rq_xid = svc_getu32(argv);
1236
1237	dir  = svc_getnl(argv);
1238	if (dir != 0) {
1239		/* direction != CALL */
1240		svc_printk(rqstp, "bad direction %d, dropping request\n", dir);
1241		serv->sv_stats->rpcbadfmt++;
1242		svc_drop(rqstp);
1243		return 0;
1244	}
1245
1246	/* Returns 1 for send, 0 for drop */
1247	if (svc_process_common(rqstp, argv, resv))
1248		return svc_send(rqstp);
1249	else {
1250		svc_drop(rqstp);
1251		return 0;
1252	}
 
 
 
 
1253}
 
1254
1255#if defined(CONFIG_SUNRPC_BACKCHANNEL)
1256/*
1257 * Process a backchannel RPC request that arrived over an existing
1258 * outbound connection
1259 */
1260int
1261bc_svc_process(struct svc_serv *serv, struct rpc_rqst *req,
1262	       struct svc_rqst *rqstp)
1263{
1264	struct kvec	*argv = &rqstp->rq_arg.head[0];
1265	struct kvec	*resv = &rqstp->rq_res.head[0];
 
 
 
 
 
1266
1267	/* Build the svc_rqst used by the common processing routine */
1268	rqstp->rq_xprt = serv->sv_bc_xprt;
1269	rqstp->rq_xid = req->rq_xid;
1270	rqstp->rq_prot = req->rq_xprt->prot;
1271	rqstp->rq_server = serv;
1272
1273	rqstp->rq_addrlen = sizeof(req->rq_xprt->addr);
1274	memcpy(&rqstp->rq_addr, &req->rq_xprt->addr, rqstp->rq_addrlen);
1275	memcpy(&rqstp->rq_arg, &req->rq_rcv_buf, sizeof(rqstp->rq_arg));
1276	memcpy(&rqstp->rq_res, &req->rq_snd_buf, sizeof(rqstp->rq_res));
1277
 
 
 
 
 
 
 
 
 
 
 
 
 
1278	/* reset result send buffer "put" position */
1279	resv->iov_len = 0;
1280
1281	if (rqstp->rq_prot != IPPROTO_TCP) {
1282		printk(KERN_ERR "No support for Non-TCP transports!\n");
1283		BUG();
1284	}
1285
1286	/*
1287	 * Skip the next two words because they've already been
1288	 * processed in the trasport
1289	 */
1290	svc_getu32(argv);	/* XID */
1291	svc_getnl(argv);	/* CALLDIR */
1292
1293	/* Returns 1 for send, 0 for drop */
1294	if (svc_process_common(rqstp, argv, resv)) {
1295		memcpy(&req->rq_snd_buf, &rqstp->rq_res,
1296						sizeof(req->rq_snd_buf));
1297		return bc_send(req);
1298	} else {
1299		/* Nothing to do to drop request */
1300		return 0;
1301	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1302}
1303EXPORT_SYMBOL_GPL(bc_svc_process);
1304#endif /* CONFIG_SUNRPC_BACKCHANNEL */
1305
1306/*
1307 * Return (transport-specific) limit on the rpc payload.
1308 */
1309u32 svc_max_payload(const struct svc_rqst *rqstp)
1310{
1311	u32 max = rqstp->rq_xprt->xpt_class->xcl_max_payload;
1312
1313	if (rqstp->rq_server->sv_max_payload < max)
1314		max = rqstp->rq_server->sv_max_payload;
1315	return max;
1316}
1317EXPORT_SYMBOL_GPL(svc_max_payload);