1/*
   2 * linux/net/sunrpc/svc_xprt.c
   3 *
   4 * Author: Tom Tucker <tom@opengridcomputing.com>
   5 */
   6
   7#include <linux/sched.h>
   8#include <linux/errno.h>
   9#include <linux/freezer.h>
  10#include <linux/kthread.h>
  11#include <linux/slab.h>
  12#include <net/sock.h>
  13#include <linux/sunrpc/addr.h>
  14#include <linux/sunrpc/stats.h>
  15#include <linux/sunrpc/svc_xprt.h>
  16#include <linux/sunrpc/svcsock.h>
  17#include <linux/sunrpc/xprt.h>
  18#include <linux/module.h>
  19#include <linux/netdevice.h>
  20#include <trace/events/sunrpc.h>
  21
  22#define RPCDBG_FACILITY	RPCDBG_SVCXPRT
  23
  24static unsigned int svc_rpc_per_connection_limit __read_mostly;
  25module_param(svc_rpc_per_connection_limit, uint, 0644);
  26
  27
  28static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt);
  29static int svc_deferred_recv(struct svc_rqst *rqstp);
  30static struct cache_deferred_req *svc_defer(struct cache_req *req);
  31static void svc_age_temp_xprts(struct timer_list *t);
  32static void svc_delete_xprt(struct svc_xprt *xprt);
  33
  34/* apparently the "standard" is that clients close
  35 * idle connections after 5 minutes, servers after
  36 * 6 minutes
  37 *   http://www.connectathon.org/talks96/nfstcp.pdf
  38 */
  39static int svc_conn_age_period = 6*60;
  40
  41/* List of registered transport classes */
  42static DEFINE_SPINLOCK(svc_xprt_class_lock);
  43static LIST_HEAD(svc_xprt_class_list);
  44
  45/* SMP locking strategy:
  46 *
  47 *	svc_pool->sp_lock protects most of the fields of that pool.
  48 *	svc_serv->sv_lock protects sv_tempsocks, sv_permsocks, sv_tmpcnt.
  49 *	when both need to be taken (rare), svc_serv->sv_lock is first.
  50 *	The "service mutex" protects svc_serv->sv_nrthread.
  51 *	svc_sock->sk_lock protects the svc_sock->sk_deferred list
  52 *             and the ->sk_info_authunix cache.
  53 *
  54 *	The XPT_BUSY bit in xprt->xpt_flags prevents a transport being
  55 *	enqueued multiply. During normal transport processing this bit
  56 *	is set by svc_xprt_enqueue and cleared by svc_xprt_received.
  57 *	Providers should not manipulate this bit directly.
  58 *
  59 *	Some flags can be set to certain values at any time
  60 *	providing that certain rules are followed:
  61 *
  62 *	XPT_CONN, XPT_DATA:
  63 *		- Can be set or cleared at any time.
  64 *		- After a set, svc_xprt_enqueue must be called to enqueue
  65 *		  the transport for processing.
  66 *		- After a clear, the transport must be read/accepted.
  67 *		  If this succeeds, it must be set again.
  68 *	XPT_CLOSE:
  69 *		- Can set at any time. It is never cleared.
  70 *      XPT_DEAD:
  71 *		- Can only be set while XPT_BUSY is held which ensures
  72 *		  that no other thread will be using the transport or will
  73 *		  try to set XPT_DEAD.
  74 */
  75int svc_reg_xprt_class(struct svc_xprt_class *xcl)
  76{
  77	struct svc_xprt_class *cl;
  78	int res = -EEXIST;
  79
  80	dprintk("svc: Adding svc transport class '%s'\n", xcl->xcl_name);
  81
  82	INIT_LIST_HEAD(&xcl->xcl_list);
  83	spin_lock(&svc_xprt_class_lock);
  84	/* Make sure there isn't already a class with the same name */
  85	list_for_each_entry(cl, &svc_xprt_class_list, xcl_list) {
  86		if (strcmp(xcl->xcl_name, cl->xcl_name) == 0)
  87			goto out;
  88	}
  89	list_add_tail(&xcl->xcl_list, &svc_xprt_class_list);
  90	res = 0;
  91out:
  92	spin_unlock(&svc_xprt_class_lock);
  93	return res;
  94}
  95EXPORT_SYMBOL_GPL(svc_reg_xprt_class);
  96
  97void svc_unreg_xprt_class(struct svc_xprt_class *xcl)
  98{
  99	dprintk("svc: Removing svc transport class '%s'\n", xcl->xcl_name);
 100	spin_lock(&svc_xprt_class_lock);
 101	list_del_init(&xcl->xcl_list);
 102	spin_unlock(&svc_xprt_class_lock);
 103}
 104EXPORT_SYMBOL_GPL(svc_unreg_xprt_class);
 105
 106/*
 107 * Format the transport list for printing
 108 */
 109int svc_print_xprts(char *buf, int maxlen)
 110{
 111	struct svc_xprt_class *xcl;
 112	char tmpstr[80];
 113	int len = 0;
 114	buf[0] = '\0';
 115
 116	spin_lock(&svc_xprt_class_lock);
 117	list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
 118		int slen;
 119
 120		sprintf(tmpstr, "%s %d\n", xcl->xcl_name, xcl->xcl_max_payload);
 121		slen = strlen(tmpstr);
 122		if (len + slen > maxlen)
 123			break;
 124		len += slen;
 125		strcat(buf, tmpstr);
 126	}
 127	spin_unlock(&svc_xprt_class_lock);
 128
 129	return len;
 130}
 131
 132static void svc_xprt_free(struct kref *kref)
 133{
 134	struct svc_xprt *xprt =
 135		container_of(kref, struct svc_xprt, xpt_ref);
 136	struct module *owner = xprt->xpt_class->xcl_owner;
 137	if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags))
 138		svcauth_unix_info_release(xprt);
 139	put_net(xprt->xpt_net);
 140	/* See comment on corresponding get in xs_setup_bc_tcp(): */
 141	if (xprt->xpt_bc_xprt)
 142		xprt_put(xprt->xpt_bc_xprt);
 143	if (xprt->xpt_bc_xps)
 144		xprt_switch_put(xprt->xpt_bc_xps);
 145	xprt->xpt_ops->xpo_free(xprt);
 146	module_put(owner);
 147}
 148
 149void svc_xprt_put(struct svc_xprt *xprt)
 150{
 151	kref_put(&xprt->xpt_ref, svc_xprt_free);
 152}
 153EXPORT_SYMBOL_GPL(svc_xprt_put);
 154
 155/*
 156 * Called by transport drivers to initialize the transport independent
 157 * portion of the transport instance.
 158 */
 159void svc_xprt_init(struct net *net, struct svc_xprt_class *xcl,
 160		   struct svc_xprt *xprt, struct svc_serv *serv)
 161{
 162	memset(xprt, 0, sizeof(*xprt));
 163	xprt->xpt_class = xcl;
 164	xprt->xpt_ops = xcl->xcl_ops;
 165	kref_init(&xprt->xpt_ref);
 166	xprt->xpt_server = serv;
 167	INIT_LIST_HEAD(&xprt->xpt_list);
 168	INIT_LIST_HEAD(&xprt->xpt_ready);
 169	INIT_LIST_HEAD(&xprt->xpt_deferred);
 170	INIT_LIST_HEAD(&xprt->xpt_users);
 171	mutex_init(&xprt->xpt_mutex);
 172	spin_lock_init(&xprt->xpt_lock);
 173	set_bit(XPT_BUSY, &xprt->xpt_flags);
 174	rpc_init_wait_queue(&xprt->xpt_bc_pending, "xpt_bc_pending");
 175	xprt->xpt_net = get_net(net);
 176	strcpy(xprt->xpt_remotebuf, "uninitialized");
 177}
 178EXPORT_SYMBOL_GPL(svc_xprt_init);
 179
 180static struct svc_xprt *__svc_xpo_create(struct svc_xprt_class *xcl,
 181					 struct svc_serv *serv,
 182					 struct net *net,
 183					 const int family,
 184					 const unsigned short port,
 185					 int flags)
 186{
 187	struct sockaddr_in sin = {
 188		.sin_family		= AF_INET,
 189		.sin_addr.s_addr	= htonl(INADDR_ANY),
 190		.sin_port		= htons(port),
 191	};
 192#if IS_ENABLED(CONFIG_IPV6)
 193	struct sockaddr_in6 sin6 = {
 194		.sin6_family		= AF_INET6,
 195		.sin6_addr		= IN6ADDR_ANY_INIT,
 196		.sin6_port		= htons(port),
 197	};
 198#endif
 199	struct sockaddr *sap;
 200	size_t len;
 201
 202	switch (family) {
 203	case PF_INET:
 204		sap = (struct sockaddr *)&sin;
 205		len = sizeof(sin);
 206		break;
 207#if IS_ENABLED(CONFIG_IPV6)
 208	case PF_INET6:
 209		sap = (struct sockaddr *)&sin6;
 210		len = sizeof(sin6);
 211		break;
 212#endif
 213	default:
 214		return ERR_PTR(-EAFNOSUPPORT);
 215	}
 216
 217	return xcl->xcl_ops->xpo_create(serv, net, sap, len, flags);
 218}
 219
 220/*
 221 * svc_xprt_received conditionally queues the transport for processing
 222 * by another thread. The caller must hold the XPT_BUSY bit and must
 223 * not thereafter touch transport data.
 224 *
 225 * Note: XPT_DATA only gets cleared when a read-attempt finds no (or
 226 * insufficient) data.
 227 */
 228static void svc_xprt_received(struct svc_xprt *xprt)
 229{
 230	if (!test_bit(XPT_BUSY, &xprt->xpt_flags)) {
 231		WARN_ONCE(1, "xprt=0x%p already busy!", xprt);
 232		return;
 233	}
 234
 235	/* As soon as we clear busy, the xprt could be closed and
 236	 * 'put', so we need a reference to call svc_enqueue_xprt with:
 237	 */
 238	svc_xprt_get(xprt);
 239	smp_mb__before_atomic();
 240	clear_bit(XPT_BUSY, &xprt->xpt_flags);
 241	xprt->xpt_server->sv_ops->svo_enqueue_xprt(xprt);
 242	svc_xprt_put(xprt);
 243}
 244
 245void svc_add_new_perm_xprt(struct svc_serv *serv, struct svc_xprt *new)
 246{
 247	clear_bit(XPT_TEMP, &new->xpt_flags);
 248	spin_lock_bh(&serv->sv_lock);
 249	list_add(&new->xpt_list, &serv->sv_permsocks);
 250	spin_unlock_bh(&serv->sv_lock);
 251	svc_xprt_received(new);
 252}
 253
 254static int _svc_create_xprt(struct svc_serv *serv, const char *xprt_name,
 255			    struct net *net, const int family,
 256			    const unsigned short port, int flags)
 257{
 258	struct svc_xprt_class *xcl;
 259
 
 260	spin_lock(&svc_xprt_class_lock);
 261	list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
 262		struct svc_xprt *newxprt;
 263		unsigned short newport;
 264
 265		if (strcmp(xprt_name, xcl->xcl_name))
 266			continue;
 267
 268		if (!try_module_get(xcl->xcl_owner))
 269			goto err;
 270
 271		spin_unlock(&svc_xprt_class_lock);
 272		newxprt = __svc_xpo_create(xcl, serv, net, family, port, flags);
 273		if (IS_ERR(newxprt)) {
 274			module_put(xcl->xcl_owner);
 275			return PTR_ERR(newxprt);
 276		}
 277		svc_add_new_perm_xprt(serv, newxprt);
 278		newport = svc_xprt_local_port(newxprt);
 279		return newport;
 280	}
 281 err:
 282	spin_unlock(&svc_xprt_class_lock);
 
 
 283	/* This errno is exposed to user space.  Provide a reasonable
 284	 * perror msg for a bad transport. */
 285	return -EPROTONOSUPPORT;
 286}
 287
 288int svc_create_xprt(struct svc_serv *serv, const char *xprt_name,
 289		    struct net *net, const int family,
 290		    const unsigned short port, int flags)
 291{
 292	int err;
 293
 294	dprintk("svc: creating transport %s[%d]\n", xprt_name, port);
 295	err = _svc_create_xprt(serv, xprt_name, net, family, port, flags);
 296	if (err == -EPROTONOSUPPORT) {
 297		request_module("svc%s", xprt_name);
 298		err = _svc_create_xprt(serv, xprt_name, net, family, port, flags);
 299	}
 300	if (err)
 301		dprintk("svc: transport %s not found, err %d\n",
 302			xprt_name, err);
 303	return err;
 304}
 305EXPORT_SYMBOL_GPL(svc_create_xprt);
 306
 307/*
 308 * Copy the local and remote xprt addresses to the rqstp structure
 309 */
 310void svc_xprt_copy_addrs(struct svc_rqst *rqstp, struct svc_xprt *xprt)
 311{
 312	memcpy(&rqstp->rq_addr, &xprt->xpt_remote, xprt->xpt_remotelen);
 313	rqstp->rq_addrlen = xprt->xpt_remotelen;
 314
 315	/*
 316	 * Destination address in request is needed for binding the
 317	 * source address in RPC replies/callbacks later.
 318	 */
 319	memcpy(&rqstp->rq_daddr, &xprt->xpt_local, xprt->xpt_locallen);
 320	rqstp->rq_daddrlen = xprt->xpt_locallen;
 321}
 322EXPORT_SYMBOL_GPL(svc_xprt_copy_addrs);
 323
 324/**
 325 * svc_print_addr - Format rq_addr field for printing
 326 * @rqstp: svc_rqst struct containing address to print
 327 * @buf: target buffer for formatted address
 328 * @len: length of target buffer
 329 *
 330 */
 331char *svc_print_addr(struct svc_rqst *rqstp, char *buf, size_t len)
 332{
 333	return __svc_print_addr(svc_addr(rqstp), buf, len);
 334}
 335EXPORT_SYMBOL_GPL(svc_print_addr);
 336
 337static bool svc_xprt_slots_in_range(struct svc_xprt *xprt)
 338{
 339	unsigned int limit = svc_rpc_per_connection_limit;
 340	int nrqsts = atomic_read(&xprt->xpt_nr_rqsts);
 341
 342	return limit == 0 || (nrqsts >= 0 && nrqsts < limit);
 343}
 344
 345static bool svc_xprt_reserve_slot(struct svc_rqst *rqstp, struct svc_xprt *xprt)
 346{
 347	if (!test_bit(RQ_DATA, &rqstp->rq_flags)) {
 348		if (!svc_xprt_slots_in_range(xprt))
 349			return false;
 350		atomic_inc(&xprt->xpt_nr_rqsts);
 351		set_bit(RQ_DATA, &rqstp->rq_flags);
 352	}
 353	return true;
 354}
 355
 356static void svc_xprt_release_slot(struct svc_rqst *rqstp)
 357{
 358	struct svc_xprt	*xprt = rqstp->rq_xprt;
 359	if (test_and_clear_bit(RQ_DATA, &rqstp->rq_flags)) {
 360		atomic_dec(&xprt->xpt_nr_rqsts);
 361		svc_xprt_enqueue(xprt);
 362	}
 363}
 364
 365static bool svc_xprt_has_something_to_do(struct svc_xprt *xprt)
 366{
 367	if (xprt->xpt_flags & ((1<<XPT_CONN)|(1<<XPT_CLOSE)))
 368		return true;
 369	if (xprt->xpt_flags & ((1<<XPT_DATA)|(1<<XPT_DEFERRED))) {
 370		if (xprt->xpt_ops->xpo_has_wspace(xprt) &&
 371		    svc_xprt_slots_in_range(xprt))
 372			return true;
 373		trace_svc_xprt_no_write_space(xprt);
 374		return false;
 375	}
 376	return false;
 377}
 378
 379void svc_xprt_do_enqueue(struct svc_xprt *xprt)
 380{
 381	struct svc_pool *pool;
 382	struct svc_rqst	*rqstp = NULL;
 383	int cpu;
 
 384
 385	if (!svc_xprt_has_something_to_do(xprt))
 386		return;
 387
 388	/* Mark transport as busy. It will remain in this state until
 389	 * the provider calls svc_xprt_received. We update XPT_BUSY
 390	 * atomically because it also guards against trying to enqueue
 391	 * the transport twice.
 392	 */
 393	if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
 394		return;
 
 
 
 395
 396	cpu = get_cpu();
 397	pool = svc_pool_for_cpu(xprt->xpt_server, cpu);
 398
 399	atomic_long_inc(&pool->sp_stats.packets);
 400
 401	spin_lock_bh(&pool->sp_lock);
 402	list_add_tail(&xprt->xpt_ready, &pool->sp_sockets);
 403	pool->sp_stats.sockets_queued++;
 404	spin_unlock_bh(&pool->sp_lock);
 405
 406	/* find a thread for this xprt */
 407	rcu_read_lock();
 408	list_for_each_entry_rcu(rqstp, &pool->sp_all_threads, rq_all) {
 409		if (test_and_set_bit(RQ_BUSY, &rqstp->rq_flags))
 
 410			continue;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 411		atomic_long_inc(&pool->sp_stats.threads_woken);
 412		rqstp->rq_qtime = ktime_get();
 413		wake_up_process(rqstp->rq_task);
 414		goto out_unlock;
 
 415	}
 416	set_bit(SP_CONGESTED, &pool->sp_flags);
 417	rqstp = NULL;
 418out_unlock:
 419	rcu_read_unlock();
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 420	put_cpu();
 
 421	trace_svc_xprt_do_enqueue(xprt, rqstp);
 422}
 423EXPORT_SYMBOL_GPL(svc_xprt_do_enqueue);
 424
 425/*
 426 * Queue up a transport with data pending. If there are idle nfsd
 427 * processes, wake 'em up.
 428 *
 429 */
 430void svc_xprt_enqueue(struct svc_xprt *xprt)
 431{
 432	if (test_bit(XPT_BUSY, &xprt->xpt_flags))
 433		return;
 434	xprt->xpt_server->sv_ops->svo_enqueue_xprt(xprt);
 435}
 436EXPORT_SYMBOL_GPL(svc_xprt_enqueue);
 437
 438/*
 439 * Dequeue the first transport, if there is one.
 440 */
 441static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool)
 442{
 443	struct svc_xprt	*xprt = NULL;
 444
 445	if (list_empty(&pool->sp_sockets))
 446		goto out;
 447
 448	spin_lock_bh(&pool->sp_lock);
 449	if (likely(!list_empty(&pool->sp_sockets))) {
 450		xprt = list_first_entry(&pool->sp_sockets,
 451					struct svc_xprt, xpt_ready);
 452		list_del_init(&xprt->xpt_ready);
 453		svc_xprt_get(xprt);
 
 
 
 454	}
 455	spin_unlock_bh(&pool->sp_lock);
 456out:
 
 457	return xprt;
 458}
 459
 460/**
 461 * svc_reserve - change the space reserved for the reply to a request.
 462 * @rqstp:  The request in question
 463 * @space: new max space to reserve
 464 *
 465 * Each request reserves some space on the output queue of the transport
 466 * to make sure the reply fits.  This function reduces that reserved
 467 * space to be the amount of space used already, plus @space.
 468 *
 469 */
 470void svc_reserve(struct svc_rqst *rqstp, int space)
 471{
 472	space += rqstp->rq_res.head[0].iov_len;
 473
 474	if (space < rqstp->rq_reserved) {
 475		struct svc_xprt *xprt = rqstp->rq_xprt;
 476		atomic_sub((rqstp->rq_reserved - space), &xprt->xpt_reserved);
 477		rqstp->rq_reserved = space;
 478
 
 
 479		svc_xprt_enqueue(xprt);
 480	}
 481}
 482EXPORT_SYMBOL_GPL(svc_reserve);
 483
 484static void svc_xprt_release(struct svc_rqst *rqstp)
 485{
 486	struct svc_xprt	*xprt = rqstp->rq_xprt;
 487
 488	xprt->xpt_ops->xpo_release_rqst(rqstp);
 489
 490	kfree(rqstp->rq_deferred);
 491	rqstp->rq_deferred = NULL;
 492
 493	svc_free_res_pages(rqstp);
 494	rqstp->rq_res.page_len = 0;
 495	rqstp->rq_res.page_base = 0;
 496
 497	/* Reset response buffer and release
 498	 * the reservation.
 499	 * But first, check that enough space was reserved
 500	 * for the reply, otherwise we have a bug!
 501	 */
 502	if ((rqstp->rq_res.len) >  rqstp->rq_reserved)
 503		printk(KERN_ERR "RPC request reserved %d but used %d\n",
 504		       rqstp->rq_reserved,
 505		       rqstp->rq_res.len);
 506
 507	rqstp->rq_res.head[0].iov_len = 0;
 508	svc_reserve(rqstp, 0);
 509	svc_xprt_release_slot(rqstp);
 510	rqstp->rq_xprt = NULL;
 
 511	svc_xprt_put(xprt);
 512}
 513
 514/*
 515 * Some svc_serv's will have occasional work to do, even when a xprt is not
 516 * waiting to be serviced. This function is there to "kick" a task in one of
 517 * those services so that it can wake up and do that work. Note that we only
 518 * bother with pool 0 as we don't need to wake up more than one thread for
 519 * this purpose.
 520 */
 521void svc_wake_up(struct svc_serv *serv)
 522{
 523	struct svc_rqst	*rqstp;
 524	struct svc_pool *pool;
 525
 526	pool = &serv->sv_pools[0];
 527
 528	rcu_read_lock();
 529	list_for_each_entry_rcu(rqstp, &pool->sp_all_threads, rq_all) {
 530		/* skip any that aren't queued */
 531		if (test_bit(RQ_BUSY, &rqstp->rq_flags))
 532			continue;
 533		rcu_read_unlock();
 
 534		wake_up_process(rqstp->rq_task);
 535		trace_svc_wake_up(rqstp->rq_task->pid);
 536		return;
 537	}
 538	rcu_read_unlock();
 539
 540	/* No free entries available */
 541	set_bit(SP_TASK_PENDING, &pool->sp_flags);
 542	smp_wmb();
 543	trace_svc_wake_up(0);
 544}
 545EXPORT_SYMBOL_GPL(svc_wake_up);
 546
 547int svc_port_is_privileged(struct sockaddr *sin)
 548{
 549	switch (sin->sa_family) {
 550	case AF_INET:
 551		return ntohs(((struct sockaddr_in *)sin)->sin_port)
 552			< PROT_SOCK;
 553	case AF_INET6:
 554		return ntohs(((struct sockaddr_in6 *)sin)->sin6_port)
 555			< PROT_SOCK;
 556	default:
 557		return 0;
 558	}
 559}
 560
 561/*
 562 * Make sure that we don't have too many active connections. If we have,
 563 * something must be dropped. It's not clear what will happen if we allow
 564 * "too many" connections, but when dealing with network-facing software,
 565 * we have to code defensively. Here we do that by imposing hard limits.
 566 *
 567 * There's no point in trying to do random drop here for DoS
 568 * prevention. The NFS clients does 1 reconnect in 15 seconds. An
 569 * attacker can easily beat that.
 570 *
 571 * The only somewhat efficient mechanism would be if drop old
 572 * connections from the same IP first. But right now we don't even
 573 * record the client IP in svc_sock.
 574 *
 575 * single-threaded services that expect a lot of clients will probably
 576 * need to set sv_maxconn to override the default value which is based
 577 * on the number of threads
 578 */
 579static void svc_check_conn_limits(struct svc_serv *serv)
 580{
 581	unsigned int limit = serv->sv_maxconn ? serv->sv_maxconn :
 582				(serv->sv_nrthreads+3) * 20;
 583
 584	if (serv->sv_tmpcnt > limit) {
 585		struct svc_xprt *xprt = NULL;
 586		spin_lock_bh(&serv->sv_lock);
 587		if (!list_empty(&serv->sv_tempsocks)) {
 588			/* Try to help the admin */
 589			net_notice_ratelimited("%s: too many open connections, consider increasing the %s\n",
 590					       serv->sv_name, serv->sv_maxconn ?
 591					       "max number of connections" :
 592					       "number of threads");
 593			/*
 594			 * Always select the oldest connection. It's not fair,
 595			 * but so is life
 596			 */
 597			xprt = list_entry(serv->sv_tempsocks.prev,
 598					  struct svc_xprt,
 599					  xpt_list);
 600			set_bit(XPT_CLOSE, &xprt->xpt_flags);
 601			svc_xprt_get(xprt);
 602		}
 603		spin_unlock_bh(&serv->sv_lock);
 604
 605		if (xprt) {
 606			svc_xprt_enqueue(xprt);
 607			svc_xprt_put(xprt);
 608		}
 609	}
 610}
 611
 612static int svc_alloc_arg(struct svc_rqst *rqstp)
 613{
 614	struct svc_serv *serv = rqstp->rq_server;
 615	struct xdr_buf *arg;
 616	int pages;
 617	int i;
 618
 619	/* now allocate needed pages.  If we get a failure, sleep briefly */
 620	pages = (serv->sv_max_mesg + 2 * PAGE_SIZE) >> PAGE_SHIFT;
 621	if (pages > RPCSVC_MAXPAGES) {
 622		pr_warn_once("svc: warning: pages=%u > RPCSVC_MAXPAGES=%lu\n",
 623			     pages, RPCSVC_MAXPAGES);
 624		/* use as many pages as possible */
 625		pages = RPCSVC_MAXPAGES;
 626	}
 627	for (i = 0; i < pages ; i++)
 628		while (rqstp->rq_pages[i] == NULL) {
 629			struct page *p = alloc_page(GFP_KERNEL);
 630			if (!p) {
 631				set_current_state(TASK_INTERRUPTIBLE);
 632				if (signalled() || kthread_should_stop()) {
 633					set_current_state(TASK_RUNNING);
 634					return -EINTR;
 635				}
 636				schedule_timeout(msecs_to_jiffies(500));
 637			}
 638			rqstp->rq_pages[i] = p;
 639		}
 640	rqstp->rq_page_end = &rqstp->rq_pages[i];
 641	rqstp->rq_pages[i++] = NULL; /* this might be seen in nfs_read_actor */
 642
 643	/* Make arg->head point to first page and arg->pages point to rest */
 644	arg = &rqstp->rq_arg;
 645	arg->head[0].iov_base = page_address(rqstp->rq_pages[0]);
 646	arg->head[0].iov_len = PAGE_SIZE;
 647	arg->pages = rqstp->rq_pages + 1;
 648	arg->page_base = 0;
 649	/* save at least one page for response */
 650	arg->page_len = (pages-2)*PAGE_SIZE;
 651	arg->len = (pages-1)*PAGE_SIZE;
 652	arg->tail[0].iov_len = 0;
 653	return 0;
 654}
 655
 656static bool
 657rqst_should_sleep(struct svc_rqst *rqstp)
 658{
 659	struct svc_pool		*pool = rqstp->rq_pool;
 660
 661	/* did someone call svc_wake_up? */
 662	if (test_and_clear_bit(SP_TASK_PENDING, &pool->sp_flags))
 663		return false;
 664
 665	/* was a socket queued? */
 666	if (!list_empty(&pool->sp_sockets))
 667		return false;
 668
 669	/* are we shutting down? */
 670	if (signalled() || kthread_should_stop())
 671		return false;
 672
 673	/* are we freezing? */
 674	if (freezing(current))
 675		return false;
 676
 677	return true;
 678}
 679
 680static struct svc_xprt *svc_get_next_xprt(struct svc_rqst *rqstp, long timeout)
 681{
 
 682	struct svc_pool		*pool = rqstp->rq_pool;
 683	long			time_left = 0;
 684
 685	/* rq_xprt should be clear on entry */
 686	WARN_ON_ONCE(rqstp->rq_xprt);
 687
 688	rqstp->rq_xprt = svc_xprt_dequeue(pool);
 689	if (rqstp->rq_xprt)
 690		goto out_found;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 691
 692	/*
 693	 * We have to be able to interrupt this wait
 694	 * to bring down the daemons ...
 695	 */
 696	set_current_state(TASK_INTERRUPTIBLE);
 697	smp_mb__before_atomic();
 698	clear_bit(SP_CONGESTED, &pool->sp_flags);
 699	clear_bit(RQ_BUSY, &rqstp->rq_flags);
 700	smp_mb__after_atomic();
 701
 702	if (likely(rqst_should_sleep(rqstp)))
 703		time_left = schedule_timeout(timeout);
 704	else
 705		__set_current_state(TASK_RUNNING);
 706
 707	try_to_freeze();
 708
 
 709	set_bit(RQ_BUSY, &rqstp->rq_flags);
 710	smp_mb__after_atomic();
 711	rqstp->rq_xprt = svc_xprt_dequeue(pool);
 712	if (rqstp->rq_xprt)
 713		goto out_found;
 
 714
 715	if (!time_left)
 716		atomic_long_inc(&pool->sp_stats.threads_timedout);
 717
 718	if (signalled() || kthread_should_stop())
 719		return ERR_PTR(-EINTR);
 720	return ERR_PTR(-EAGAIN);
 721out_found:
 722	/* Normally we will wait up to 5 seconds for any required
 723	 * cache information to be provided.
 724	 */
 725	if (!test_bit(SP_CONGESTED, &pool->sp_flags))
 726		rqstp->rq_chandle.thread_wait = 5*HZ;
 727	else
 728		rqstp->rq_chandle.thread_wait = 1*HZ;
 729	trace_svc_xprt_dequeue(rqstp);
 730	return rqstp->rq_xprt;
 731}
 732
 733static void svc_add_new_temp_xprt(struct svc_serv *serv, struct svc_xprt *newxpt)
 734{
 735	spin_lock_bh(&serv->sv_lock);
 736	set_bit(XPT_TEMP, &newxpt->xpt_flags);
 737	list_add(&newxpt->xpt_list, &serv->sv_tempsocks);
 738	serv->sv_tmpcnt++;
 739	if (serv->sv_temptimer.function == NULL) {
 740		/* setup timer to age temp transports */
 741		serv->sv_temptimer.function = svc_age_temp_xprts;
 
 742		mod_timer(&serv->sv_temptimer,
 743			  jiffies + svc_conn_age_period * HZ);
 744	}
 745	spin_unlock_bh(&serv->sv_lock);
 746	svc_xprt_received(newxpt);
 747}
 748
 749static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
 750{
 751	struct svc_serv *serv = rqstp->rq_server;
 752	int len = 0;
 753
 754	if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) {
 755		dprintk("svc_recv: found XPT_CLOSE\n");
 756		if (test_and_clear_bit(XPT_KILL_TEMP, &xprt->xpt_flags))
 757			xprt->xpt_ops->xpo_kill_temp_xprt(xprt);
 758		svc_delete_xprt(xprt);
 759		/* Leave XPT_BUSY set on the dead xprt: */
 760		goto out;
 761	}
 762	if (test_bit(XPT_LISTENER, &xprt->xpt_flags)) {
 763		struct svc_xprt *newxpt;
 764		/*
 765		 * We know this module_get will succeed because the
 766		 * listener holds a reference too
 767		 */
 768		__module_get(xprt->xpt_class->xcl_owner);
 769		svc_check_conn_limits(xprt->xpt_server);
 770		newxpt = xprt->xpt_ops->xpo_accept(xprt);
 771		if (newxpt)
 772			svc_add_new_temp_xprt(serv, newxpt);
 773		else
 774			module_put(xprt->xpt_class->xcl_owner);
 775	} else if (svc_xprt_reserve_slot(rqstp, xprt)) {
 776		/* XPT_DATA|XPT_DEFERRED case: */
 777		dprintk("svc: server %p, pool %u, transport %p, inuse=%d\n",
 778			rqstp, rqstp->rq_pool->sp_id, xprt,
 779			kref_read(&xprt->xpt_ref));
 780		rqstp->rq_deferred = svc_deferred_dequeue(xprt);
 781		if (rqstp->rq_deferred)
 782			len = svc_deferred_recv(rqstp);
 783		else
 784			len = xprt->xpt_ops->xpo_recvfrom(rqstp);
 785		rqstp->rq_stime = ktime_get();
 786		rqstp->rq_reserved = serv->sv_max_mesg;
 787		atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
 788	}
 789	/* clear XPT_BUSY: */
 790	svc_xprt_received(xprt);
 791out:
 792	trace_svc_handle_xprt(xprt, len);
 793	return len;
 794}
 795
 796/*
 797 * Receive the next request on any transport.  This code is carefully
 798 * organised not to touch any cachelines in the shared svc_serv
 799 * structure, only cachelines in the local svc_pool.
 800 */
 801int svc_recv(struct svc_rqst *rqstp, long timeout)
 802{
 803	struct svc_xprt		*xprt = NULL;
 804	struct svc_serv		*serv = rqstp->rq_server;
 805	int			len, err;
 806
 807	dprintk("svc: server %p waiting for data (to = %ld)\n",
 808		rqstp, timeout);
 809
 810	if (rqstp->rq_xprt)
 811		printk(KERN_ERR
 812			"svc_recv: service %p, transport not NULL!\n",
 813			 rqstp);
 814
 815	err = svc_alloc_arg(rqstp);
 816	if (err)
 817		goto out;
 818
 819	try_to_freeze();
 820	cond_resched();
 821	err = -EINTR;
 822	if (signalled() || kthread_should_stop())
 823		goto out;
 824
 825	xprt = svc_get_next_xprt(rqstp, timeout);
 826	if (IS_ERR(xprt)) {
 827		err = PTR_ERR(xprt);
 828		goto out;
 829	}
 830
 831	len = svc_handle_xprt(rqstp, xprt);
 832
 833	/* No data, incomplete (TCP) read, or accept() */
 834	err = -EAGAIN;
 835	if (len <= 0)
 836		goto out_release;
 837
 838	clear_bit(XPT_OLD, &xprt->xpt_flags);
 839
 840	xprt->xpt_ops->xpo_secure_port(rqstp);
 
 
 
 841	rqstp->rq_chandle.defer = svc_defer;
 842	rqstp->rq_xid = svc_getu32(&rqstp->rq_arg.head[0]);
 843
 844	if (serv->sv_stats)
 845		serv->sv_stats->netcnt++;
 846	trace_svc_recv(rqstp, len);
 847	return len;
 848out_release:
 849	rqstp->rq_res.len = 0;
 850	svc_xprt_release(rqstp);
 851out:
 
 852	return err;
 853}
 854EXPORT_SYMBOL_GPL(svc_recv);
 855
 856/*
 857 * Drop request
 858 */
 859void svc_drop(struct svc_rqst *rqstp)
 860{
 861	trace_svc_drop(rqstp);
 862	dprintk("svc: xprt %p dropped request\n", rqstp->rq_xprt);
 863	svc_xprt_release(rqstp);
 864}
 865EXPORT_SYMBOL_GPL(svc_drop);
 866
 867/*
 868 * Return reply to client.
 869 */
 870int svc_send(struct svc_rqst *rqstp)
 871{
 872	struct svc_xprt	*xprt;
 873	int		len = -EFAULT;
 874	struct xdr_buf	*xb;
 875
 876	xprt = rqstp->rq_xprt;
 877	if (!xprt)
 878		goto out;
 879
 880	/* release the receive skb before sending the reply */
 881	xprt->xpt_ops->xpo_release_rqst(rqstp);
 882
 883	/* calculate over-all length */
 884	xb = &rqstp->rq_res;
 885	xb->len = xb->head[0].iov_len +
 886		xb->page_len +
 887		xb->tail[0].iov_len;
 888
 889	/* Grab mutex to serialize outgoing data. */
 890	mutex_lock(&xprt->xpt_mutex);
 891	trace_svc_stats_latency(rqstp);
 892	if (test_bit(XPT_DEAD, &xprt->xpt_flags)
 893			|| test_bit(XPT_CLOSE, &xprt->xpt_flags))
 894		len = -ENOTCONN;
 895	else
 896		len = xprt->xpt_ops->xpo_sendto(rqstp);
 897	mutex_unlock(&xprt->xpt_mutex);
 898	rpc_wake_up(&xprt->xpt_bc_pending);
 899	trace_svc_send(rqstp, len);
 900	svc_xprt_release(rqstp);
 901
 902	if (len == -ECONNREFUSED || len == -ENOTCONN || len == -EAGAIN)
 903		len = 0;
 904out:
 
 905	return len;
 906}
 907
 908/*
 909 * Timer function to close old temporary transports, using
 910 * a mark-and-sweep algorithm.
 911 */
 912static void svc_age_temp_xprts(struct timer_list *t)
 913{
 914	struct svc_serv *serv = from_timer(serv, t, sv_temptimer);
 915	struct svc_xprt *xprt;
 916	struct list_head *le, *next;
 917
 918	dprintk("svc_age_temp_xprts\n");
 919
 920	if (!spin_trylock_bh(&serv->sv_lock)) {
 921		/* busy, try again 1 sec later */
 922		dprintk("svc_age_temp_xprts: busy\n");
 923		mod_timer(&serv->sv_temptimer, jiffies + HZ);
 924		return;
 925	}
 926
 927	list_for_each_safe(le, next, &serv->sv_tempsocks) {
 928		xprt = list_entry(le, struct svc_xprt, xpt_list);
 929
 930		/* First time through, just mark it OLD. Second time
 931		 * through, close it. */
 932		if (!test_and_set_bit(XPT_OLD, &xprt->xpt_flags))
 933			continue;
 934		if (kref_read(&xprt->xpt_ref) > 1 ||
 935		    test_bit(XPT_BUSY, &xprt->xpt_flags))
 936			continue;
 937		list_del_init(le);
 938		set_bit(XPT_CLOSE, &xprt->xpt_flags);
 939		dprintk("queuing xprt %p for closing\n", xprt);
 940
 941		/* a thread will dequeue and close it soon */
 942		svc_xprt_enqueue(xprt);
 943	}
 944	spin_unlock_bh(&serv->sv_lock);
 945
 946	mod_timer(&serv->sv_temptimer, jiffies + svc_conn_age_period * HZ);
 947}
 948
 949/* Close temporary transports whose xpt_local matches server_addr immediately
 950 * instead of waiting for them to be picked up by the timer.
 951 *
 952 * This is meant to be called from a notifier_block that runs when an ip
 953 * address is deleted.
 954 */
 955void svc_age_temp_xprts_now(struct svc_serv *serv, struct sockaddr *server_addr)
 956{
 957	struct svc_xprt *xprt;
 
 
 958	struct list_head *le, *next;
 959	LIST_HEAD(to_be_closed);
 
 
 
 
 960
 961	spin_lock_bh(&serv->sv_lock);
 962	list_for_each_safe(le, next, &serv->sv_tempsocks) {
 963		xprt = list_entry(le, struct svc_xprt, xpt_list);
 964		if (rpc_cmp_addr(server_addr, (struct sockaddr *)
 965				&xprt->xpt_local)) {
 966			dprintk("svc_age_temp_xprts_now: found %p\n", xprt);
 967			list_move(le, &to_be_closed);
 968		}
 969	}
 970	spin_unlock_bh(&serv->sv_lock);
 971
 972	while (!list_empty(&to_be_closed)) {
 973		le = to_be_closed.next;
 974		list_del_init(le);
 975		xprt = list_entry(le, struct svc_xprt, xpt_list);
 976		set_bit(XPT_CLOSE, &xprt->xpt_flags);
 977		set_bit(XPT_KILL_TEMP, &xprt->xpt_flags);
 978		dprintk("svc_age_temp_xprts_now: queuing xprt %p for closing\n",
 979				xprt);
 980		svc_xprt_enqueue(xprt);
 
 981	}
 982}
 983EXPORT_SYMBOL_GPL(svc_age_temp_xprts_now);
 984
 985static void call_xpt_users(struct svc_xprt *xprt)
 986{
 987	struct svc_xpt_user *u;
 988
 989	spin_lock(&xprt->xpt_lock);
 990	while (!list_empty(&xprt->xpt_users)) {
 991		u = list_first_entry(&xprt->xpt_users, struct svc_xpt_user, list);
 992		list_del(&u->list);
 993		u->callback(u);
 994	}
 995	spin_unlock(&xprt->xpt_lock);
 996}
 997
 998/*
 999 * Remove a dead transport
1000 */
1001static void svc_delete_xprt(struct svc_xprt *xprt)
1002{
1003	struct svc_serv	*serv = xprt->xpt_server;
1004	struct svc_deferred_req *dr;
1005
1006	/* Only do this once */
1007	if (test_and_set_bit(XPT_DEAD, &xprt->xpt_flags))
1008		BUG();
1009
1010	dprintk("svc: svc_delete_xprt(%p)\n", xprt);
1011	xprt->xpt_ops->xpo_detach(xprt);
1012
1013	spin_lock_bh(&serv->sv_lock);
1014	list_del_init(&xprt->xpt_list);
1015	WARN_ON_ONCE(!list_empty(&xprt->xpt_ready));
1016	if (test_bit(XPT_TEMP, &xprt->xpt_flags))
1017		serv->sv_tmpcnt--;
1018	spin_unlock_bh(&serv->sv_lock);
1019
1020	while ((dr = svc_deferred_dequeue(xprt)) != NULL)
1021		kfree(dr);
1022
1023	call_xpt_users(xprt);
1024	svc_xprt_put(xprt);
1025}
1026
1027void svc_close_xprt(struct svc_xprt *xprt)
1028{
1029	set_bit(XPT_CLOSE, &xprt->xpt_flags);
1030	if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
1031		/* someone else will have to effect the close */
1032		return;
1033	/*
1034	 * We expect svc_close_xprt() to work even when no threads are
1035	 * running (e.g., while configuring the server before starting
1036	 * any threads), so if the transport isn't busy, we delete
1037	 * it ourself:
1038	 */
1039	svc_delete_xprt(xprt);
1040}
1041EXPORT_SYMBOL_GPL(svc_close_xprt);
1042
1043static int svc_close_list(struct svc_serv *serv, struct list_head *xprt_list, struct net *net)
1044{
1045	struct svc_xprt *xprt;
1046	int ret = 0;
1047
1048	spin_lock(&serv->sv_lock);
1049	list_for_each_entry(xprt, xprt_list, xpt_list) {
1050		if (xprt->xpt_net != net)
1051			continue;
1052		ret++;
1053		set_bit(XPT_CLOSE, &xprt->xpt_flags);
1054		svc_xprt_enqueue(xprt);
1055	}
1056	spin_unlock(&serv->sv_lock);
1057	return ret;
1058}
1059
1060static struct svc_xprt *svc_dequeue_net(struct svc_serv *serv, struct net *net)
1061{
1062	struct svc_pool *pool;
1063	struct svc_xprt *xprt;
1064	struct svc_xprt *tmp;
1065	int i;
1066
1067	for (i = 0; i < serv->sv_nrpools; i++) {
1068		pool = &serv->sv_pools[i];
1069
1070		spin_lock_bh(&pool->sp_lock);
1071		list_for_each_entry_safe(xprt, tmp, &pool->sp_sockets, xpt_ready) {
1072			if (xprt->xpt_net != net)
1073				continue;
1074			list_del_init(&xprt->xpt_ready);
1075			spin_unlock_bh(&pool->sp_lock);
1076			return xprt;
1077		}
1078		spin_unlock_bh(&pool->sp_lock);
1079	}
1080	return NULL;
1081}
1082
1083static void svc_clean_up_xprts(struct svc_serv *serv, struct net *net)
1084{
1085	struct svc_xprt *xprt;
1086
1087	while ((xprt = svc_dequeue_net(serv, net))) {
1088		set_bit(XPT_CLOSE, &xprt->xpt_flags);
1089		svc_delete_xprt(xprt);
1090	}
1091}
1092
1093/*
1094 * Server threads may still be running (especially in the case where the
1095 * service is still running in other network namespaces).
1096 *
1097 * So we shut down sockets the same way we would on a running server, by
1098 * setting XPT_CLOSE, enqueuing, and letting a thread pick it up to do
1099 * the close.  In the case there are no such other threads,
1100 * threads running, svc_clean_up_xprts() does a simple version of a
1101 * server's main event loop, and in the case where there are other
1102 * threads, we may need to wait a little while and then check again to
1103 * see if they're done.
1104 */
1105void svc_close_net(struct svc_serv *serv, struct net *net)
1106{
1107	int delay = 0;
1108
1109	while (svc_close_list(serv, &serv->sv_permsocks, net) +
1110	       svc_close_list(serv, &serv->sv_tempsocks, net)) {
1111
1112		svc_clean_up_xprts(serv, net);
1113		msleep(delay++);
1114	}
1115}
1116
1117/*
1118 * Handle defer and revisit of requests
1119 */
1120
1121static void svc_revisit(struct cache_deferred_req *dreq, int too_many)
1122{
1123	struct svc_deferred_req *dr =
1124		container_of(dreq, struct svc_deferred_req, handle);
1125	struct svc_xprt *xprt = dr->xprt;
1126
1127	spin_lock(&xprt->xpt_lock);
1128	set_bit(XPT_DEFERRED, &xprt->xpt_flags);
1129	if (too_many || test_bit(XPT_DEAD, &xprt->xpt_flags)) {
1130		spin_unlock(&xprt->xpt_lock);
1131		dprintk("revisit canceled\n");
1132		svc_xprt_put(xprt);
1133		trace_svc_drop_deferred(dr);
1134		kfree(dr);
1135		return;
1136	}
1137	dprintk("revisit queued\n");
1138	dr->xprt = NULL;
1139	list_add(&dr->handle.recent, &xprt->xpt_deferred);
1140	spin_unlock(&xprt->xpt_lock);
1141	svc_xprt_enqueue(xprt);
1142	svc_xprt_put(xprt);
1143}
1144
1145/*
1146 * Save the request off for later processing. The request buffer looks
1147 * like this:
1148 *
1149 * <xprt-header><rpc-header><rpc-pagelist><rpc-tail>
1150 *
1151 * This code can only handle requests that consist of an xprt-header
1152 * and rpc-header.
1153 */
1154static struct cache_deferred_req *svc_defer(struct cache_req *req)
1155{
1156	struct svc_rqst *rqstp = container_of(req, struct svc_rqst, rq_chandle);
1157	struct svc_deferred_req *dr;
1158
1159	if (rqstp->rq_arg.page_len || !test_bit(RQ_USEDEFERRAL, &rqstp->rq_flags))
1160		return NULL; /* if more than a page, give up FIXME */
1161	if (rqstp->rq_deferred) {
1162		dr = rqstp->rq_deferred;
1163		rqstp->rq_deferred = NULL;
1164	} else {
1165		size_t skip;
1166		size_t size;
1167		/* FIXME maybe discard if size too large */
1168		size = sizeof(struct svc_deferred_req) + rqstp->rq_arg.len;
1169		dr = kmalloc(size, GFP_KERNEL);
1170		if (dr == NULL)
1171			return NULL;
1172
1173		dr->handle.owner = rqstp->rq_server;
1174		dr->prot = rqstp->rq_prot;
1175		memcpy(&dr->addr, &rqstp->rq_addr, rqstp->rq_addrlen);
1176		dr->addrlen = rqstp->rq_addrlen;
1177		dr->daddr = rqstp->rq_daddr;
1178		dr->argslen = rqstp->rq_arg.len >> 2;
1179		dr->xprt_hlen = rqstp->rq_xprt_hlen;
1180
1181		/* back up head to the start of the buffer and copy */
1182		skip = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len;
1183		memcpy(dr->args, rqstp->rq_arg.head[0].iov_base - skip,
1184		       dr->argslen << 2);
1185	}
1186	svc_xprt_get(rqstp->rq_xprt);
1187	dr->xprt = rqstp->rq_xprt;
1188	set_bit(RQ_DROPME, &rqstp->rq_flags);
1189
1190	dr->handle.revisit = svc_revisit;
1191	trace_svc_defer(rqstp);
1192	return &dr->handle;
1193}
1194
1195/*
1196 * recv data from a deferred request into an active one
1197 */
1198static int svc_deferred_recv(struct svc_rqst *rqstp)
1199{
1200	struct svc_deferred_req *dr = rqstp->rq_deferred;
1201
1202	/* setup iov_base past transport header */
1203	rqstp->rq_arg.head[0].iov_base = dr->args + (dr->xprt_hlen>>2);
1204	/* The iov_len does not include the transport header bytes */
1205	rqstp->rq_arg.head[0].iov_len = (dr->argslen<<2) - dr->xprt_hlen;
1206	rqstp->rq_arg.page_len = 0;
1207	/* The rq_arg.len includes the transport header bytes */
1208	rqstp->rq_arg.len     = dr->argslen<<2;
1209	rqstp->rq_prot        = dr->prot;
1210	memcpy(&rqstp->rq_addr, &dr->addr, dr->addrlen);
1211	rqstp->rq_addrlen     = dr->addrlen;
1212	/* Save off transport header len in case we get deferred again */
1213	rqstp->rq_xprt_hlen   = dr->xprt_hlen;
1214	rqstp->rq_daddr       = dr->daddr;
1215	rqstp->rq_respages    = rqstp->rq_pages;
1216	return (dr->argslen<<2) - dr->xprt_hlen;
1217}
1218
1219
1220static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt)
1221{
1222	struct svc_deferred_req *dr = NULL;
1223
1224	if (!test_bit(XPT_DEFERRED, &xprt->xpt_flags))
1225		return NULL;
1226	spin_lock(&xprt->xpt_lock);
1227	if (!list_empty(&xprt->xpt_deferred)) {
1228		dr = list_entry(xprt->xpt_deferred.next,
1229				struct svc_deferred_req,
1230				handle.recent);
1231		list_del_init(&dr->handle.recent);
1232		trace_svc_revisit_deferred(dr);
1233	} else
1234		clear_bit(XPT_DEFERRED, &xprt->xpt_flags);
1235	spin_unlock(&xprt->xpt_lock);
1236	return dr;
1237}
1238
1239/**
1240 * svc_find_xprt - find an RPC transport instance
1241 * @serv: pointer to svc_serv to search
1242 * @xcl_name: C string containing transport's class name
1243 * @net: owner net pointer
1244 * @af: Address family of transport's local address
1245 * @port: transport's IP port number
1246 *
1247 * Return the transport instance pointer for the endpoint accepting
1248 * connections/peer traffic from the specified transport class,
1249 * address family and port.
1250 *
1251 * Specifying 0 for the address family or port is effectively a
1252 * wild-card, and will result in matching the first transport in the
1253 * service's list that has a matching class name.
1254 */
1255struct svc_xprt *svc_find_xprt(struct svc_serv *serv, const char *xcl_name,
1256			       struct net *net, const sa_family_t af,
1257			       const unsigned short port)
1258{
1259	struct svc_xprt *xprt;
1260	struct svc_xprt *found = NULL;
1261
1262	/* Sanity check the args */
1263	if (serv == NULL || xcl_name == NULL)
1264		return found;
1265
1266	spin_lock_bh(&serv->sv_lock);
1267	list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1268		if (xprt->xpt_net != net)
1269			continue;
1270		if (strcmp(xprt->xpt_class->xcl_name, xcl_name))
1271			continue;
1272		if (af != AF_UNSPEC && af != xprt->xpt_local.ss_family)
1273			continue;
1274		if (port != 0 && port != svc_xprt_local_port(xprt))
1275			continue;
1276		found = xprt;
1277		svc_xprt_get(xprt);
1278		break;
1279	}
1280	spin_unlock_bh(&serv->sv_lock);
1281	return found;
1282}
1283EXPORT_SYMBOL_GPL(svc_find_xprt);
1284
1285static int svc_one_xprt_name(const struct svc_xprt *xprt,
1286			     char *pos, int remaining)
1287{
1288	int len;
1289
1290	len = snprintf(pos, remaining, "%s %u\n",
1291			xprt->xpt_class->xcl_name,
1292			svc_xprt_local_port(xprt));
1293	if (len >= remaining)
1294		return -ENAMETOOLONG;
1295	return len;
1296}
1297
1298/**
1299 * svc_xprt_names - format a buffer with a list of transport names
1300 * @serv: pointer to an RPC service
1301 * @buf: pointer to a buffer to be filled in
1302 * @buflen: length of buffer to be filled in
1303 *
1304 * Fills in @buf with a string containing a list of transport names,
1305 * each name terminated with '\n'.
1306 *
1307 * Returns positive length of the filled-in string on success; otherwise
1308 * a negative errno value is returned if an error occurs.
1309 */
1310int svc_xprt_names(struct svc_serv *serv, char *buf, const int buflen)
1311{
1312	struct svc_xprt *xprt;
1313	int len, totlen;
1314	char *pos;
1315
1316	/* Sanity check args */
1317	if (!serv)
1318		return 0;
1319
1320	spin_lock_bh(&serv->sv_lock);
1321
1322	pos = buf;
1323	totlen = 0;
1324	list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1325		len = svc_one_xprt_name(xprt, pos, buflen - totlen);
1326		if (len < 0) {
1327			*buf = '\0';
1328			totlen = len;
1329		}
1330		if (len <= 0)
1331			break;
1332
1333		pos += len;
1334		totlen += len;
1335	}
1336
1337	spin_unlock_bh(&serv->sv_lock);
1338	return totlen;
1339}
1340EXPORT_SYMBOL_GPL(svc_xprt_names);
1341
1342
1343/*----------------------------------------------------------------------------*/
1344
1345static void *svc_pool_stats_start(struct seq_file *m, loff_t *pos)
1346{
1347	unsigned int pidx = (unsigned int)*pos;
1348	struct svc_serv *serv = m->private;
1349
1350	dprintk("svc_pool_stats_start, *pidx=%u\n", pidx);
1351
1352	if (!pidx)
1353		return SEQ_START_TOKEN;
1354	return (pidx > serv->sv_nrpools ? NULL : &serv->sv_pools[pidx-1]);
1355}
1356
1357static void *svc_pool_stats_next(struct seq_file *m, void *p, loff_t *pos)
1358{
1359	struct svc_pool *pool = p;
1360	struct svc_serv *serv = m->private;
1361
1362	dprintk("svc_pool_stats_next, *pos=%llu\n", *pos);
1363
1364	if (p == SEQ_START_TOKEN) {
1365		pool = &serv->sv_pools[0];
1366	} else {
1367		unsigned int pidx = (pool - &serv->sv_pools[0]);
1368		if (pidx < serv->sv_nrpools-1)
1369			pool = &serv->sv_pools[pidx+1];
1370		else
1371			pool = NULL;
1372	}
1373	++*pos;
1374	return pool;
1375}
1376
1377static void svc_pool_stats_stop(struct seq_file *m, void *p)
1378{
1379}
1380
1381static int svc_pool_stats_show(struct seq_file *m, void *p)
1382{
1383	struct svc_pool *pool = p;
1384
1385	if (p == SEQ_START_TOKEN) {
1386		seq_puts(m, "# pool packets-arrived sockets-enqueued threads-woken threads-timedout\n");
1387		return 0;
1388	}
1389
1390	seq_printf(m, "%u %lu %lu %lu %lu\n",
1391		pool->sp_id,
1392		(unsigned long)atomic_long_read(&pool->sp_stats.packets),
1393		pool->sp_stats.sockets_queued,
1394		(unsigned long)atomic_long_read(&pool->sp_stats.threads_woken),
1395		(unsigned long)atomic_long_read(&pool->sp_stats.threads_timedout));
1396
1397	return 0;
1398}
1399
1400static const struct seq_operations svc_pool_stats_seq_ops = {
1401	.start	= svc_pool_stats_start,
1402	.next	= svc_pool_stats_next,
1403	.stop	= svc_pool_stats_stop,
1404	.show	= svc_pool_stats_show,
1405};
1406
1407int svc_pool_stats_open(struct svc_serv *serv, struct file *file)
1408{
1409	int err;
1410
1411	err = seq_open(file, &svc_pool_stats_seq_ops);
1412	if (!err)
1413		((struct seq_file *) file->private_data)->private = serv;
1414	return err;
1415}
1416EXPORT_SYMBOL(svc_pool_stats_open);
1417
1418/*----------------------------------------------------------------------------*/