1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * linux/net/sunrpc/svc_xprt.c
   4 *
   5 * Author: Tom Tucker <tom@opengridcomputing.com>
   6 */
   7
   8#include <linux/sched.h>
   9#include <linux/sched/mm.h>
  10#include <linux/errno.h>
  11#include <linux/freezer.h>
 
  12#include <linux/slab.h>
  13#include <net/sock.h>
  14#include <linux/sunrpc/addr.h>
  15#include <linux/sunrpc/stats.h>
  16#include <linux/sunrpc/svc_xprt.h>
  17#include <linux/sunrpc/svcsock.h>
  18#include <linux/sunrpc/xprt.h>
  19#include <linux/sunrpc/bc_xprt.h>
  20#include <linux/module.h>
  21#include <linux/netdevice.h>
  22#include <trace/events/sunrpc.h>
  23
  24#define RPCDBG_FACILITY	RPCDBG_SVCXPRT
  25
  26static unsigned int svc_rpc_per_connection_limit __read_mostly;
  27module_param(svc_rpc_per_connection_limit, uint, 0644);
  28
  29
  30static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt);
  31static int svc_deferred_recv(struct svc_rqst *rqstp);
  32static struct cache_deferred_req *svc_defer(struct cache_req *req);
  33static void svc_age_temp_xprts(struct timer_list *t);
  34static void svc_delete_xprt(struct svc_xprt *xprt);
  35
  36/* apparently the "standard" is that clients close
  37 * idle connections after 5 minutes, servers after
  38 * 6 minutes
  39 *   http://nfsv4bat.org/Documents/ConnectAThon/1996/nfstcp.pdf
  40 */
  41static int svc_conn_age_period = 6*60;
  42
  43/* List of registered transport classes */
  44static DEFINE_SPINLOCK(svc_xprt_class_lock);
  45static LIST_HEAD(svc_xprt_class_list);
  46
  47/* SMP locking strategy:
  48 *
  49 *	svc_pool->sp_lock protects most of the fields of that pool.
  50 *	svc_serv->sv_lock protects sv_tempsocks, sv_permsocks, sv_tmpcnt.
  51 *	when both need to be taken (rare), svc_serv->sv_lock is first.
  52 *	The "service mutex" protects svc_serv->sv_nrthread.
  53 *	svc_sock->sk_lock protects the svc_sock->sk_deferred list
  54 *             and the ->sk_info_authunix cache.
  55 *
  56 *	The XPT_BUSY bit in xprt->xpt_flags prevents a transport being
  57 *	enqueued multiply. During normal transport processing this bit
  58 *	is set by svc_xprt_enqueue and cleared by svc_xprt_received.
  59 *	Providers should not manipulate this bit directly.
  60 *
  61 *	Some flags can be set to certain values at any time
  62 *	providing that certain rules are followed:
  63 *
  64 *	XPT_CONN, XPT_DATA:
  65 *		- Can be set or cleared at any time.
  66 *		- After a set, svc_xprt_enqueue must be called to enqueue
  67 *		  the transport for processing.
  68 *		- After a clear, the transport must be read/accepted.
  69 *		  If this succeeds, it must be set again.
  70 *	XPT_CLOSE:
  71 *		- Can set at any time. It is never cleared.
  72 *      XPT_DEAD:
  73 *		- Can only be set while XPT_BUSY is held which ensures
  74 *		  that no other thread will be using the transport or will
  75 *		  try to set XPT_DEAD.
  76 */
  77
  78/**
  79 * svc_reg_xprt_class - Register a server-side RPC transport class
  80 * @xcl: New transport class to be registered
  81 *
  82 * Returns zero on success; otherwise a negative errno is returned.
  83 */
  84int svc_reg_xprt_class(struct svc_xprt_class *xcl)
  85{
  86	struct svc_xprt_class *cl;
  87	int res = -EEXIST;
  88
 
 
  89	INIT_LIST_HEAD(&xcl->xcl_list);
  90	spin_lock(&svc_xprt_class_lock);
  91	/* Make sure there isn't already a class with the same name */
  92	list_for_each_entry(cl, &svc_xprt_class_list, xcl_list) {
  93		if (strcmp(xcl->xcl_name, cl->xcl_name) == 0)
  94			goto out;
  95	}
  96	list_add_tail(&xcl->xcl_list, &svc_xprt_class_list);
  97	res = 0;
  98out:
  99	spin_unlock(&svc_xprt_class_lock);
 100	return res;
 101}
 102EXPORT_SYMBOL_GPL(svc_reg_xprt_class);
 103
 104/**
 105 * svc_unreg_xprt_class - Unregister a server-side RPC transport class
 106 * @xcl: Transport class to be unregistered
 107 *
 108 */
 109void svc_unreg_xprt_class(struct svc_xprt_class *xcl)
 110{
 
 111	spin_lock(&svc_xprt_class_lock);
 112	list_del_init(&xcl->xcl_list);
 113	spin_unlock(&svc_xprt_class_lock);
 114}
 115EXPORT_SYMBOL_GPL(svc_unreg_xprt_class);
 116
 117/**
 118 * svc_print_xprts - Format the transport list for printing
 119 * @buf: target buffer for formatted address
 120 * @maxlen: length of target buffer
 121 *
 122 * Fills in @buf with a string containing a list of transport names, each name
 123 * terminated with '\n'. If the buffer is too small, some entries may be
 124 * missing, but it is guaranteed that all lines in the output buffer are
 125 * complete.
 126 *
 127 * Returns positive length of the filled-in string.
 128 */
 129int svc_print_xprts(char *buf, int maxlen)
 130{
 131	struct svc_xprt_class *xcl;
 132	char tmpstr[80];
 133	int len = 0;
 134	buf[0] = '\0';
 135
 136	spin_lock(&svc_xprt_class_lock);
 137	list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
 138		int slen;
 139
 140		slen = snprintf(tmpstr, sizeof(tmpstr), "%s %d\n",
 141				xcl->xcl_name, xcl->xcl_max_payload);
 142		if (slen >= sizeof(tmpstr) || len + slen >= maxlen)
 143			break;
 144		len += slen;
 145		strcat(buf, tmpstr);
 146	}
 147	spin_unlock(&svc_xprt_class_lock);
 148
 149	return len;
 150}
 151
 152/**
 153 * svc_xprt_deferred_close - Close a transport
 154 * @xprt: transport instance
 155 *
 156 * Used in contexts that need to defer the work of shutting down
 157 * the transport to an nfsd thread.
 158 */
 159void svc_xprt_deferred_close(struct svc_xprt *xprt)
 160{
 161	if (!test_and_set_bit(XPT_CLOSE, &xprt->xpt_flags))
 162		svc_xprt_enqueue(xprt);
 163}
 164EXPORT_SYMBOL_GPL(svc_xprt_deferred_close);
 165
 166static void svc_xprt_free(struct kref *kref)
 167{
 168	struct svc_xprt *xprt =
 169		container_of(kref, struct svc_xprt, xpt_ref);
 170	struct module *owner = xprt->xpt_class->xcl_owner;
 171	if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags))
 172		svcauth_unix_info_release(xprt);
 173	put_cred(xprt->xpt_cred);
 174	put_net_track(xprt->xpt_net, &xprt->ns_tracker);
 175	/* See comment on corresponding get in xs_setup_bc_tcp(): */
 176	if (xprt->xpt_bc_xprt)
 177		xprt_put(xprt->xpt_bc_xprt);
 178	if (xprt->xpt_bc_xps)
 179		xprt_switch_put(xprt->xpt_bc_xps);
 180	trace_svc_xprt_free(xprt);
 181	xprt->xpt_ops->xpo_free(xprt);
 182	module_put(owner);
 183}
 184
 185void svc_xprt_put(struct svc_xprt *xprt)
 186{
 187	kref_put(&xprt->xpt_ref, svc_xprt_free);
 188}
 189EXPORT_SYMBOL_GPL(svc_xprt_put);
 190
 191/*
 192 * Called by transport drivers to initialize the transport independent
 193 * portion of the transport instance.
 194 */
 195void svc_xprt_init(struct net *net, struct svc_xprt_class *xcl,
 196		   struct svc_xprt *xprt, struct svc_serv *serv)
 197{
 198	memset(xprt, 0, sizeof(*xprt));
 199	xprt->xpt_class = xcl;
 200	xprt->xpt_ops = xcl->xcl_ops;
 201	kref_init(&xprt->xpt_ref);
 202	xprt->xpt_server = serv;
 203	INIT_LIST_HEAD(&xprt->xpt_list);
 
 204	INIT_LIST_HEAD(&xprt->xpt_deferred);
 205	INIT_LIST_HEAD(&xprt->xpt_users);
 206	mutex_init(&xprt->xpt_mutex);
 207	spin_lock_init(&xprt->xpt_lock);
 208	set_bit(XPT_BUSY, &xprt->xpt_flags);
 209	xprt->xpt_net = get_net_track(net, &xprt->ns_tracker, GFP_ATOMIC);
 210	strcpy(xprt->xpt_remotebuf, "uninitialized");
 211}
 212EXPORT_SYMBOL_GPL(svc_xprt_init);
 213
 214static struct svc_xprt *__svc_xpo_create(struct svc_xprt_class *xcl,
 215					 struct svc_serv *serv,
 216					 struct net *net,
 217					 const int family,
 218					 const unsigned short port,
 219					 int flags)
 220{
 221	struct sockaddr_in sin = {
 222		.sin_family		= AF_INET,
 223		.sin_addr.s_addr	= htonl(INADDR_ANY),
 224		.sin_port		= htons(port),
 225	};
 226#if IS_ENABLED(CONFIG_IPV6)
 227	struct sockaddr_in6 sin6 = {
 228		.sin6_family		= AF_INET6,
 229		.sin6_addr		= IN6ADDR_ANY_INIT,
 230		.sin6_port		= htons(port),
 231	};
 232#endif
 233	struct svc_xprt *xprt;
 234	struct sockaddr *sap;
 235	size_t len;
 236
 237	switch (family) {
 238	case PF_INET:
 239		sap = (struct sockaddr *)&sin;
 240		len = sizeof(sin);
 241		break;
 242#if IS_ENABLED(CONFIG_IPV6)
 243	case PF_INET6:
 244		sap = (struct sockaddr *)&sin6;
 245		len = sizeof(sin6);
 246		break;
 247#endif
 248	default:
 249		return ERR_PTR(-EAFNOSUPPORT);
 250	}
 251
 252	xprt = xcl->xcl_ops->xpo_create(serv, net, sap, len, flags);
 253	if (IS_ERR(xprt))
 254		trace_svc_xprt_create_err(serv->sv_program->pg_name,
 255					  xcl->xcl_name, sap, len, xprt);
 256	return xprt;
 257}
 258
 259/**
 260 * svc_xprt_received - start next receiver thread
 261 * @xprt: controlling transport
 262 *
 263 * The caller must hold the XPT_BUSY bit and must
 264 * not thereafter touch transport data.
 265 *
 266 * Note: XPT_DATA only gets cleared when a read-attempt finds no (or
 267 * insufficient) data.
 268 */
 269void svc_xprt_received(struct svc_xprt *xprt)
 270{
 271	if (!test_bit(XPT_BUSY, &xprt->xpt_flags)) {
 272		WARN_ONCE(1, "xprt=0x%p already busy!", xprt);
 273		return;
 274	}
 275
 276	/* As soon as we clear busy, the xprt could be closed and
 277	 * 'put', so we need a reference to call svc_xprt_enqueue with:
 278	 */
 279	svc_xprt_get(xprt);
 280	smp_mb__before_atomic();
 281	clear_bit(XPT_BUSY, &xprt->xpt_flags);
 282	svc_xprt_enqueue(xprt);
 283	svc_xprt_put(xprt);
 284}
 285EXPORT_SYMBOL_GPL(svc_xprt_received);
 286
 287void svc_add_new_perm_xprt(struct svc_serv *serv, struct svc_xprt *new)
 288{
 289	clear_bit(XPT_TEMP, &new->xpt_flags);
 290	spin_lock_bh(&serv->sv_lock);
 291	list_add(&new->xpt_list, &serv->sv_permsocks);
 292	spin_unlock_bh(&serv->sv_lock);
 293	svc_xprt_received(new);
 294}
 295
 296static int _svc_xprt_create(struct svc_serv *serv, const char *xprt_name,
 297			    struct net *net, const int family,
 298			    const unsigned short port, int flags,
 299			    const struct cred *cred)
 300{
 301	struct svc_xprt_class *xcl;
 302
 303	spin_lock(&svc_xprt_class_lock);
 304	list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
 305		struct svc_xprt *newxprt;
 306		unsigned short newport;
 307
 308		if (strcmp(xprt_name, xcl->xcl_name))
 309			continue;
 310
 311		if (!try_module_get(xcl->xcl_owner))
 312			goto err;
 313
 314		spin_unlock(&svc_xprt_class_lock);
 315		newxprt = __svc_xpo_create(xcl, serv, net, family, port, flags);
 316		if (IS_ERR(newxprt)) {
 317			module_put(xcl->xcl_owner);
 318			return PTR_ERR(newxprt);
 319		}
 320		newxprt->xpt_cred = get_cred(cred);
 321		svc_add_new_perm_xprt(serv, newxprt);
 322		newport = svc_xprt_local_port(newxprt);
 323		return newport;
 324	}
 325 err:
 326	spin_unlock(&svc_xprt_class_lock);
 327	/* This errno is exposed to user space.  Provide a reasonable
 328	 * perror msg for a bad transport. */
 329	return -EPROTONOSUPPORT;
 330}
 331
 332/**
 333 * svc_xprt_create - Add a new listener to @serv
 334 * @serv: target RPC service
 335 * @xprt_name: transport class name
 336 * @net: network namespace
 337 * @family: network address family
 338 * @port: listener port
 339 * @flags: SVC_SOCK flags
 340 * @cred: credential to bind to this transport
 341 *
 342 * Return values:
 343 *   %0: New listener added successfully
 344 *   %-EPROTONOSUPPORT: Requested transport type not supported
 345 */
 346int svc_xprt_create(struct svc_serv *serv, const char *xprt_name,
 347		    struct net *net, const int family,
 348		    const unsigned short port, int flags,
 349		    const struct cred *cred)
 350{
 351	int err;
 352
 353	err = _svc_xprt_create(serv, xprt_name, net, family, port, flags, cred);
 354	if (err == -EPROTONOSUPPORT) {
 355		request_module("svc%s", xprt_name);
 356		err = _svc_xprt_create(serv, xprt_name, net, family, port, flags, cred);
 357	}
 358	return err;
 359}
 360EXPORT_SYMBOL_GPL(svc_xprt_create);
 361
 362/*
 363 * Copy the local and remote xprt addresses to the rqstp structure
 364 */
 365void svc_xprt_copy_addrs(struct svc_rqst *rqstp, struct svc_xprt *xprt)
 366{
 367	memcpy(&rqstp->rq_addr, &xprt->xpt_remote, xprt->xpt_remotelen);
 368	rqstp->rq_addrlen = xprt->xpt_remotelen;
 369
 370	/*
 371	 * Destination address in request is needed for binding the
 372	 * source address in RPC replies/callbacks later.
 373	 */
 374	memcpy(&rqstp->rq_daddr, &xprt->xpt_local, xprt->xpt_locallen);
 375	rqstp->rq_daddrlen = xprt->xpt_locallen;
 376}
 377EXPORT_SYMBOL_GPL(svc_xprt_copy_addrs);
 378
 379/**
 380 * svc_print_addr - Format rq_addr field for printing
 381 * @rqstp: svc_rqst struct containing address to print
 382 * @buf: target buffer for formatted address
 383 * @len: length of target buffer
 384 *
 385 */
 386char *svc_print_addr(struct svc_rqst *rqstp, char *buf, size_t len)
 387{
 388	return __svc_print_addr(svc_addr(rqstp), buf, len);
 389}
 390EXPORT_SYMBOL_GPL(svc_print_addr);
 391
 392static bool svc_xprt_slots_in_range(struct svc_xprt *xprt)
 393{
 394	unsigned int limit = svc_rpc_per_connection_limit;
 395	int nrqsts = atomic_read(&xprt->xpt_nr_rqsts);
 396
 397	return limit == 0 || (nrqsts >= 0 && nrqsts < limit);
 398}
 399
 400static bool svc_xprt_reserve_slot(struct svc_rqst *rqstp, struct svc_xprt *xprt)
 401{
 402	if (!test_bit(RQ_DATA, &rqstp->rq_flags)) {
 403		if (!svc_xprt_slots_in_range(xprt))
 404			return false;
 405		atomic_inc(&xprt->xpt_nr_rqsts);
 406		set_bit(RQ_DATA, &rqstp->rq_flags);
 407	}
 408	return true;
 409}
 410
 411static void svc_xprt_release_slot(struct svc_rqst *rqstp)
 412{
 413	struct svc_xprt	*xprt = rqstp->rq_xprt;
 414	if (test_and_clear_bit(RQ_DATA, &rqstp->rq_flags)) {
 415		atomic_dec(&xprt->xpt_nr_rqsts);
 416		smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */
 417		svc_xprt_enqueue(xprt);
 418	}
 419}
 420
 421static bool svc_xprt_ready(struct svc_xprt *xprt)
 422{
 423	unsigned long xpt_flags;
 424
 425	/*
 426	 * If another cpu has recently updated xpt_flags,
 427	 * sk_sock->flags, xpt_reserved, or xpt_nr_rqsts, we need to
 428	 * know about it; otherwise it's possible that both that cpu and
 429	 * this one could call svc_xprt_enqueue() without either
 430	 * svc_xprt_enqueue() recognizing that the conditions below
 431	 * are satisfied, and we could stall indefinitely:
 432	 */
 433	smp_rmb();
 434	xpt_flags = READ_ONCE(xprt->xpt_flags);
 435
 436	trace_svc_xprt_enqueue(xprt, xpt_flags);
 437	if (xpt_flags & BIT(XPT_BUSY))
 438		return false;
 439	if (xpt_flags & (BIT(XPT_CONN) | BIT(XPT_CLOSE) | BIT(XPT_HANDSHAKE)))
 440		return true;
 441	if (xpt_flags & (BIT(XPT_DATA) | BIT(XPT_DEFERRED))) {
 442		if (xprt->xpt_ops->xpo_has_wspace(xprt) &&
 443		    svc_xprt_slots_in_range(xprt))
 444			return true;
 445		trace_svc_xprt_no_write_space(xprt);
 446		return false;
 447	}
 448	return false;
 449}
 450
 451/**
 452 * svc_xprt_enqueue - Queue a transport on an idle nfsd thread
 453 * @xprt: transport with data pending
 454 *
 455 */
 456void svc_xprt_enqueue(struct svc_xprt *xprt)
 457{
 458	struct svc_pool *pool;
 
 
 459
 460	if (!svc_xprt_ready(xprt))
 461		return;
 462
 463	/* Mark transport as busy. It will remain in this state until
 464	 * the provider calls svc_xprt_received. We update XPT_BUSY
 465	 * atomically because it also guards against trying to enqueue
 466	 * the transport twice.
 467	 */
 468	if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
 469		return;
 470
 471	pool = svc_pool_for_cpu(xprt->xpt_server);
 
 472
 473	percpu_counter_inc(&pool->sp_sockets_queued);
 474	lwq_enqueue(&xprt->xpt_ready, &pool->sp_xprts);
 475
 476	svc_pool_wake_idle_thread(pool);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 477}
 478EXPORT_SYMBOL_GPL(svc_xprt_enqueue);
 479
 480/*
 481 * Dequeue the first transport, if there is one.
 482 */
 483static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool)
 484{
 485	struct svc_xprt	*xprt = NULL;
 486
 487	xprt = lwq_dequeue(&pool->sp_xprts, struct svc_xprt, xpt_ready);
 488	if (xprt)
 
 
 
 
 
 
 489		svc_xprt_get(xprt);
 
 
 
 490	return xprt;
 491}
 492
 493/**
 494 * svc_reserve - change the space reserved for the reply to a request.
 495 * @rqstp:  The request in question
 496 * @space: new max space to reserve
 497 *
 498 * Each request reserves some space on the output queue of the transport
 499 * to make sure the reply fits.  This function reduces that reserved
 500 * space to be the amount of space used already, plus @space.
 501 *
 502 */
 503void svc_reserve(struct svc_rqst *rqstp, int space)
 504{
 505	struct svc_xprt *xprt = rqstp->rq_xprt;
 506
 507	space += rqstp->rq_res.head[0].iov_len;
 508
 509	if (xprt && space < rqstp->rq_reserved) {
 510		atomic_sub((rqstp->rq_reserved - space), &xprt->xpt_reserved);
 511		rqstp->rq_reserved = space;
 512		smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */
 513		svc_xprt_enqueue(xprt);
 514	}
 515}
 516EXPORT_SYMBOL_GPL(svc_reserve);
 517
 518static void free_deferred(struct svc_xprt *xprt, struct svc_deferred_req *dr)
 519{
 520	if (!dr)
 521		return;
 522
 523	xprt->xpt_ops->xpo_release_ctxt(xprt, dr->xprt_ctxt);
 524	kfree(dr);
 525}
 526
 527static void svc_xprt_release(struct svc_rqst *rqstp)
 528{
 529	struct svc_xprt	*xprt = rqstp->rq_xprt;
 530
 531	xprt->xpt_ops->xpo_release_ctxt(xprt, rqstp->rq_xprt_ctxt);
 532	rqstp->rq_xprt_ctxt = NULL;
 533
 534	free_deferred(xprt, rqstp->rq_deferred);
 535	rqstp->rq_deferred = NULL;
 536
 537	svc_rqst_release_pages(rqstp);
 538	rqstp->rq_res.page_len = 0;
 539	rqstp->rq_res.page_base = 0;
 540
 541	/* Reset response buffer and release
 542	 * the reservation.
 543	 * But first, check that enough space was reserved
 544	 * for the reply, otherwise we have a bug!
 545	 */
 546	if ((rqstp->rq_res.len) >  rqstp->rq_reserved)
 547		printk(KERN_ERR "RPC request reserved %d but used %d\n",
 548		       rqstp->rq_reserved,
 549		       rqstp->rq_res.len);
 550
 551	rqstp->rq_res.head[0].iov_len = 0;
 552	svc_reserve(rqstp, 0);
 553	svc_xprt_release_slot(rqstp);
 554	rqstp->rq_xprt = NULL;
 555	svc_xprt_put(xprt);
 556}
 557
 558/**
 559 * svc_wake_up - Wake up a service thread for non-transport work
 560 * @serv: RPC service
 561 *
 562 * Some svc_serv's will have occasional work to do, even when a xprt is not
 563 * waiting to be serviced. This function is there to "kick" a task in one of
 564 * those services so that it can wake up and do that work. Note that we only
 565 * bother with pool 0 as we don't need to wake up more than one thread for
 566 * this purpose.
 567 */
 568void svc_wake_up(struct svc_serv *serv)
 569{
 570	struct svc_pool *pool = &serv->sv_pools[0];
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 571
 
 572	set_bit(SP_TASK_PENDING, &pool->sp_flags);
 573	svc_pool_wake_idle_thread(pool);
 
 574}
 575EXPORT_SYMBOL_GPL(svc_wake_up);
 576
 577int svc_port_is_privileged(struct sockaddr *sin)
 578{
 579	switch (sin->sa_family) {
 580	case AF_INET:
 581		return ntohs(((struct sockaddr_in *)sin)->sin_port)
 582			< PROT_SOCK;
 583	case AF_INET6:
 584		return ntohs(((struct sockaddr_in6 *)sin)->sin6_port)
 585			< PROT_SOCK;
 586	default:
 587		return 0;
 588	}
 589}
 590
 591/*
 592 * Make sure that we don't have too many active connections. If we have,
 593 * something must be dropped. It's not clear what will happen if we allow
 594 * "too many" connections, but when dealing with network-facing software,
 595 * we have to code defensively. Here we do that by imposing hard limits.
 596 *
 597 * There's no point in trying to do random drop here for DoS
 598 * prevention. The NFS clients does 1 reconnect in 15 seconds. An
 599 * attacker can easily beat that.
 600 *
 601 * The only somewhat efficient mechanism would be if drop old
 602 * connections from the same IP first. But right now we don't even
 603 * record the client IP in svc_sock.
 604 *
 605 * single-threaded services that expect a lot of clients will probably
 606 * need to set sv_maxconn to override the default value which is based
 607 * on the number of threads
 608 */
 609static void svc_check_conn_limits(struct svc_serv *serv)
 610{
 611	unsigned int limit = serv->sv_maxconn ? serv->sv_maxconn :
 612				(serv->sv_nrthreads+3) * 20;
 613
 614	if (serv->sv_tmpcnt > limit) {
 615		struct svc_xprt *xprt = NULL;
 616		spin_lock_bh(&serv->sv_lock);
 617		if (!list_empty(&serv->sv_tempsocks)) {
 618			/* Try to help the admin */
 619			net_notice_ratelimited("%s: too many open connections, consider increasing the %s\n",
 620					       serv->sv_name, serv->sv_maxconn ?
 621					       "max number of connections" :
 622					       "number of threads");
 623			/*
 624			 * Always select the oldest connection. It's not fair,
 625			 * but so is life
 626			 */
 627			xprt = list_entry(serv->sv_tempsocks.prev,
 628					  struct svc_xprt,
 629					  xpt_list);
 630			set_bit(XPT_CLOSE, &xprt->xpt_flags);
 631			svc_xprt_get(xprt);
 632		}
 633		spin_unlock_bh(&serv->sv_lock);
 634
 635		if (xprt) {
 636			svc_xprt_enqueue(xprt);
 637			svc_xprt_put(xprt);
 638		}
 639	}
 640}
 641
 642static bool svc_alloc_arg(struct svc_rqst *rqstp)
 643{
 644	struct svc_serv *serv = rqstp->rq_server;
 645	struct xdr_buf *arg = &rqstp->rq_arg;
 646	unsigned long pages, filled, ret;
 
 647
 
 648	pages = (serv->sv_max_mesg + 2 * PAGE_SIZE) >> PAGE_SHIFT;
 649	if (pages > RPCSVC_MAXPAGES) {
 650		pr_warn_once("svc: warning: pages=%lu > RPCSVC_MAXPAGES=%lu\n",
 651			     pages, RPCSVC_MAXPAGES);
 652		/* use as many pages as possible */
 653		pages = RPCSVC_MAXPAGES;
 654	}
 655
 656	for (filled = 0; filled < pages; filled = ret) {
 657		ret = alloc_pages_bulk_array(GFP_KERNEL, pages,
 658					     rqstp->rq_pages);
 659		if (ret > filled)
 660			/* Made progress, don't sleep yet */
 661			continue;
 662
 663		set_current_state(TASK_IDLE);
 664		if (svc_thread_should_stop(rqstp)) {
 665			set_current_state(TASK_RUNNING);
 666			return false;
 667		}
 668		trace_svc_alloc_arg_err(pages, ret);
 669		memalloc_retry_wait(GFP_KERNEL);
 670	}
 671	rqstp->rq_page_end = &rqstp->rq_pages[pages];
 672	rqstp->rq_pages[pages] = NULL; /* this might be seen in nfsd_splice_actor() */
 673
 674	/* Make arg->head point to first page and arg->pages point to rest */
 
 675	arg->head[0].iov_base = page_address(rqstp->rq_pages[0]);
 676	arg->head[0].iov_len = PAGE_SIZE;
 677	arg->pages = rqstp->rq_pages + 1;
 678	arg->page_base = 0;
 679	/* save at least one page for response */
 680	arg->page_len = (pages-2)*PAGE_SIZE;
 681	arg->len = (pages-1)*PAGE_SIZE;
 682	arg->tail[0].iov_len = 0;
 683
 684	rqstp->rq_xid = xdr_zero;
 685	return true;
 686}
 687
 688static bool
 689svc_thread_should_sleep(struct svc_rqst *rqstp)
 690{
 691	struct svc_pool		*pool = rqstp->rq_pool;
 692
 693	/* did someone call svc_wake_up? */
 694	if (test_bit(SP_TASK_PENDING, &pool->sp_flags))
 695		return false;
 696
 697	/* was a socket queued? */
 698	if (!lwq_empty(&pool->sp_xprts))
 699		return false;
 700
 701	/* are we shutting down? */
 702	if (svc_thread_should_stop(rqstp))
 703		return false;
 704
 705#if defined(CONFIG_SUNRPC_BACKCHANNEL)
 706	if (svc_is_backchannel(rqstp)) {
 707		if (!lwq_empty(&rqstp->rq_server->sv_cb_list))
 708			return false;
 709	}
 710#endif
 711
 712	return true;
 713}
 714
 715static void svc_thread_wait_for_work(struct svc_rqst *rqstp)
 716{
 717	struct svc_pool *pool = rqstp->rq_pool;
 
 718
 719	if (svc_thread_should_sleep(rqstp)) {
 720		set_current_state(TASK_IDLE | TASK_FREEZABLE);
 721		llist_add(&rqstp->rq_idle, &pool->sp_idle_threads);
 722		if (likely(svc_thread_should_sleep(rqstp)))
 723			schedule();
 724
 725		while (!llist_del_first_this(&pool->sp_idle_threads,
 726					     &rqstp->rq_idle)) {
 727			/* Work just became available.  This thread can only
 728			 * handle it after removing rqstp from the idle
 729			 * list. If that attempt failed, some other thread
 730			 * must have queued itself after finding no
 731			 * work to do, so that thread has taken responsibly
 732			 * for this new work.  This thread can safely sleep
 733			 * until woken again.
 734			 */
 735			schedule();
 736			set_current_state(TASK_IDLE | TASK_FREEZABLE);
 737		}
 
 738		__set_current_state(TASK_RUNNING);
 739	} else {
 740		cond_resched();
 741	}
 742	try_to_freeze();
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 743}
 744
 745static void svc_add_new_temp_xprt(struct svc_serv *serv, struct svc_xprt *newxpt)
 746{
 747	spin_lock_bh(&serv->sv_lock);
 748	set_bit(XPT_TEMP, &newxpt->xpt_flags);
 749	list_add(&newxpt->xpt_list, &serv->sv_tempsocks);
 750	serv->sv_tmpcnt++;
 751	if (serv->sv_temptimer.function == NULL) {
 752		/* setup timer to age temp transports */
 753		serv->sv_temptimer.function = svc_age_temp_xprts;
 754		mod_timer(&serv->sv_temptimer,
 755			  jiffies + svc_conn_age_period * HZ);
 756	}
 757	spin_unlock_bh(&serv->sv_lock);
 758	svc_xprt_received(newxpt);
 759}
 760
 761static void svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
 762{
 763	struct svc_serv *serv = rqstp->rq_server;
 764	int len = 0;
 765
 766	if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) {
 767		if (test_and_clear_bit(XPT_KILL_TEMP, &xprt->xpt_flags))
 768			xprt->xpt_ops->xpo_kill_temp_xprt(xprt);
 769		svc_delete_xprt(xprt);
 770		/* Leave XPT_BUSY set on the dead xprt: */
 771		goto out;
 772	}
 773	if (test_bit(XPT_LISTENER, &xprt->xpt_flags)) {
 774		struct svc_xprt *newxpt;
 775		/*
 776		 * We know this module_get will succeed because the
 777		 * listener holds a reference too
 778		 */
 779		__module_get(xprt->xpt_class->xcl_owner);
 780		svc_check_conn_limits(xprt->xpt_server);
 781		newxpt = xprt->xpt_ops->xpo_accept(xprt);
 782		if (newxpt) {
 783			newxpt->xpt_cred = get_cred(xprt->xpt_cred);
 784			svc_add_new_temp_xprt(serv, newxpt);
 785			trace_svc_xprt_accept(newxpt, serv->sv_name);
 786		} else {
 787			module_put(xprt->xpt_class->xcl_owner);
 788		}
 789		svc_xprt_received(xprt);
 790	} else if (test_bit(XPT_HANDSHAKE, &xprt->xpt_flags)) {
 791		xprt->xpt_ops->xpo_handshake(xprt);
 792		svc_xprt_received(xprt);
 793	} else if (svc_xprt_reserve_slot(rqstp, xprt)) {
 794		/* XPT_DATA|XPT_DEFERRED case: */
 
 
 
 795		rqstp->rq_deferred = svc_deferred_dequeue(xprt);
 796		if (rqstp->rq_deferred)
 797			len = svc_deferred_recv(rqstp);
 798		else
 799			len = xprt->xpt_ops->xpo_recvfrom(rqstp);
 
 
 
 800		rqstp->rq_reserved = serv->sv_max_mesg;
 801		atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
 802		if (len <= 0)
 803			goto out;
 804
 805		trace_svc_xdr_recvfrom(&rqstp->rq_arg);
 806
 807		clear_bit(XPT_OLD, &xprt->xpt_flags);
 808
 809		rqstp->rq_chandle.defer = svc_defer;
 810
 811		if (serv->sv_stats)
 812			serv->sv_stats->netcnt++;
 813		percpu_counter_inc(&rqstp->rq_pool->sp_messages_arrived);
 814		rqstp->rq_stime = ktime_get();
 815		svc_process(rqstp);
 816	} else
 817		svc_xprt_received(xprt);
 818
 819out:
 820	rqstp->rq_res.len = 0;
 821	svc_xprt_release(rqstp);
 822}
 823
 824static void svc_thread_wake_next(struct svc_rqst *rqstp)
 825{
 826	if (!svc_thread_should_sleep(rqstp))
 827		/* More work pending after I dequeued some,
 828		 * wake another worker
 829		 */
 830		svc_pool_wake_idle_thread(rqstp->rq_pool);
 831}
 832
 833/**
 834 * svc_recv - Receive and process the next request on any transport
 835 * @rqstp: an idle RPC service thread
 836 *
 837 * This code is carefully organised not to touch any cachelines in
 838 * the shared svc_serv structure, only cachelines in the local
 839 * svc_pool.
 840 */
 841void svc_recv(struct svc_rqst *rqstp)
 842{
 843	struct svc_pool *pool = rqstp->rq_pool;
 844
 845	if (!svc_alloc_arg(rqstp))
 846		return;
 847
 848	svc_thread_wait_for_work(rqstp);
 
 
 849
 850	clear_bit(SP_TASK_PENDING, &pool->sp_flags);
 
 
 
 
 851
 852	if (svc_thread_should_stop(rqstp)) {
 853		svc_thread_wake_next(rqstp);
 854		return;
 
 855	}
 856
 857	rqstp->rq_xprt = svc_xprt_dequeue(pool);
 858	if (rqstp->rq_xprt) {
 859		struct svc_xprt *xprt = rqstp->rq_xprt;
 860
 861		svc_thread_wake_next(rqstp);
 862		/* Normally we will wait up to 5 seconds for any required
 863		 * cache information to be provided.  When there are no
 864		 * idle threads, we reduce the wait time.
 865		 */
 866		if (pool->sp_idle_threads.first)
 867			rqstp->rq_chandle.thread_wait = 5 * HZ;
 868		else
 869			rqstp->rq_chandle.thread_wait = 1 * HZ;
 870
 871		trace_svc_xprt_dequeue(rqstp);
 872		svc_handle_xprt(rqstp, xprt);
 873	}
 874
 875#if defined(CONFIG_SUNRPC_BACKCHANNEL)
 876	if (svc_is_backchannel(rqstp)) {
 877		struct svc_serv *serv = rqstp->rq_server;
 878		struct rpc_rqst *req;
 879
 880		req = lwq_dequeue(&serv->sv_cb_list,
 881				  struct rpc_rqst, rq_bc_list);
 882		if (req) {
 883			svc_thread_wake_next(rqstp);
 884			svc_process_bc(req, rqstp);
 885		}
 886	}
 887#endif
 888}
 889EXPORT_SYMBOL_GPL(svc_recv);
 890
 891/*
 892 * Drop request
 893 */
 894void svc_drop(struct svc_rqst *rqstp)
 895{
 896	trace_svc_drop(rqstp);
 
 897}
 898EXPORT_SYMBOL_GPL(svc_drop);
 899
 900/**
 901 * svc_send - Return reply to client
 902 * @rqstp: RPC transaction context
 903 *
 904 */
 905void svc_send(struct svc_rqst *rqstp)
 906{
 907	struct svc_xprt	*xprt;
 
 908	struct xdr_buf	*xb;
 909	int status;
 910
 911	xprt = rqstp->rq_xprt;
 
 
 912
 913	/* calculate over-all length */
 914	xb = &rqstp->rq_res;
 915	xb->len = xb->head[0].iov_len +
 916		xb->page_len +
 917		xb->tail[0].iov_len;
 918	trace_svc_xdr_sendto(rqstp->rq_xid, xb);
 919	trace_svc_stats_latency(rqstp);
 920
 921	status = xprt->xpt_ops->xpo_sendto(rqstp);
 922
 923	trace_svc_send(rqstp, status);
 
 
 
 
 
 
 924}
 925
 926/*
 927 * Timer function to close old temporary transports, using
 928 * a mark-and-sweep algorithm.
 929 */
 930static void svc_age_temp_xprts(struct timer_list *t)
 931{
 932	struct svc_serv *serv = from_timer(serv, t, sv_temptimer);
 933	struct svc_xprt *xprt;
 934	struct list_head *le, *next;
 935
 936	dprintk("svc_age_temp_xprts\n");
 937
 938	if (!spin_trylock_bh(&serv->sv_lock)) {
 939		/* busy, try again 1 sec later */
 940		dprintk("svc_age_temp_xprts: busy\n");
 941		mod_timer(&serv->sv_temptimer, jiffies + HZ);
 942		return;
 943	}
 944
 945	list_for_each_safe(le, next, &serv->sv_tempsocks) {
 946		xprt = list_entry(le, struct svc_xprt, xpt_list);
 947
 948		/* First time through, just mark it OLD. Second time
 949		 * through, close it. */
 950		if (!test_and_set_bit(XPT_OLD, &xprt->xpt_flags))
 951			continue;
 952		if (kref_read(&xprt->xpt_ref) > 1 ||
 953		    test_bit(XPT_BUSY, &xprt->xpt_flags))
 954			continue;
 955		list_del_init(le);
 956		set_bit(XPT_CLOSE, &xprt->xpt_flags);
 957		dprintk("queuing xprt %p for closing\n", xprt);
 958
 959		/* a thread will dequeue and close it soon */
 960		svc_xprt_enqueue(xprt);
 961	}
 962	spin_unlock_bh(&serv->sv_lock);
 963
 964	mod_timer(&serv->sv_temptimer, jiffies + svc_conn_age_period * HZ);
 965}
 966
 967/* Close temporary transports whose xpt_local matches server_addr immediately
 968 * instead of waiting for them to be picked up by the timer.
 969 *
 970 * This is meant to be called from a notifier_block that runs when an ip
 971 * address is deleted.
 972 */
 973void svc_age_temp_xprts_now(struct svc_serv *serv, struct sockaddr *server_addr)
 974{
 975	struct svc_xprt *xprt;
 976	struct list_head *le, *next;
 977	LIST_HEAD(to_be_closed);
 978
 979	spin_lock_bh(&serv->sv_lock);
 980	list_for_each_safe(le, next, &serv->sv_tempsocks) {
 981		xprt = list_entry(le, struct svc_xprt, xpt_list);
 982		if (rpc_cmp_addr(server_addr, (struct sockaddr *)
 983				&xprt->xpt_local)) {
 984			dprintk("svc_age_temp_xprts_now: found %p\n", xprt);
 985			list_move(le, &to_be_closed);
 986		}
 987	}
 988	spin_unlock_bh(&serv->sv_lock);
 989
 990	while (!list_empty(&to_be_closed)) {
 991		le = to_be_closed.next;
 992		list_del_init(le);
 993		xprt = list_entry(le, struct svc_xprt, xpt_list);
 994		set_bit(XPT_CLOSE, &xprt->xpt_flags);
 995		set_bit(XPT_KILL_TEMP, &xprt->xpt_flags);
 996		dprintk("svc_age_temp_xprts_now: queuing xprt %p for closing\n",
 997				xprt);
 998		svc_xprt_enqueue(xprt);
 999	}
1000}
1001EXPORT_SYMBOL_GPL(svc_age_temp_xprts_now);
1002
1003static void call_xpt_users(struct svc_xprt *xprt)
1004{
1005	struct svc_xpt_user *u;
1006
1007	spin_lock(&xprt->xpt_lock);
1008	while (!list_empty(&xprt->xpt_users)) {
1009		u = list_first_entry(&xprt->xpt_users, struct svc_xpt_user, list);
1010		list_del_init(&u->list);
1011		u->callback(u);
1012	}
1013	spin_unlock(&xprt->xpt_lock);
1014}
1015
1016/*
1017 * Remove a dead transport
1018 */
1019static void svc_delete_xprt(struct svc_xprt *xprt)
1020{
1021	struct svc_serv	*serv = xprt->xpt_server;
1022	struct svc_deferred_req *dr;
1023
1024	if (test_and_set_bit(XPT_DEAD, &xprt->xpt_flags))
1025		return;
1026
1027	trace_svc_xprt_detach(xprt);
1028	xprt->xpt_ops->xpo_detach(xprt);
1029	if (xprt->xpt_bc_xprt)
1030		xprt->xpt_bc_xprt->ops->close(xprt->xpt_bc_xprt);
1031
1032	spin_lock_bh(&serv->sv_lock);
1033	list_del_init(&xprt->xpt_list);
 
1034	if (test_bit(XPT_TEMP, &xprt->xpt_flags))
1035		serv->sv_tmpcnt--;
1036	spin_unlock_bh(&serv->sv_lock);
1037
1038	while ((dr = svc_deferred_dequeue(xprt)) != NULL)
1039		free_deferred(xprt, dr);
1040
1041	call_xpt_users(xprt);
1042	svc_xprt_put(xprt);
1043}
1044
1045/**
1046 * svc_xprt_close - Close a client connection
1047 * @xprt: transport to disconnect
1048 *
1049 */
1050void svc_xprt_close(struct svc_xprt *xprt)
1051{
1052	trace_svc_xprt_close(xprt);
1053	set_bit(XPT_CLOSE, &xprt->xpt_flags);
1054	if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
1055		/* someone else will have to effect the close */
1056		return;
1057	/*
1058	 * We expect svc_close_xprt() to work even when no threads are
1059	 * running (e.g., while configuring the server before starting
1060	 * any threads), so if the transport isn't busy, we delete
1061	 * it ourself:
1062	 */
1063	svc_delete_xprt(xprt);
1064}
1065EXPORT_SYMBOL_GPL(svc_xprt_close);
1066
1067static int svc_close_list(struct svc_serv *serv, struct list_head *xprt_list, struct net *net)
1068{
1069	struct svc_xprt *xprt;
1070	int ret = 0;
1071
1072	spin_lock_bh(&serv->sv_lock);
1073	list_for_each_entry(xprt, xprt_list, xpt_list) {
1074		if (xprt->xpt_net != net)
1075			continue;
1076		ret++;
1077		set_bit(XPT_CLOSE, &xprt->xpt_flags);
1078		svc_xprt_enqueue(xprt);
1079	}
1080	spin_unlock_bh(&serv->sv_lock);
1081	return ret;
1082}
1083
1084static void svc_clean_up_xprts(struct svc_serv *serv, struct net *net)
1085{
 
1086	struct svc_xprt *xprt;
 
1087	int i;
1088
1089	for (i = 0; i < serv->sv_nrpools; i++) {
1090		struct svc_pool *pool = &serv->sv_pools[i];
1091		struct llist_node *q, **t1, *t2;
1092
1093		q = lwq_dequeue_all(&pool->sp_xprts);
1094		lwq_for_each_safe(xprt, t1, t2, &q, xpt_ready) {
1095			if (xprt->xpt_net == net) {
1096				set_bit(XPT_CLOSE, &xprt->xpt_flags);
1097				svc_delete_xprt(xprt);
1098				xprt = NULL;
1099			}
1100		}
 
 
 
 
 
 
 
 
1101
1102		if (q)
1103			lwq_enqueue_batch(q, &pool->sp_xprts);
 
1104	}
1105}
1106
1107/**
1108 * svc_xprt_destroy_all - Destroy transports associated with @serv
1109 * @serv: RPC service to be shut down
1110 * @net: target network namespace
1111 *
1112 * Server threads may still be running (especially in the case where the
1113 * service is still running in other network namespaces).
1114 *
1115 * So we shut down sockets the same way we would on a running server, by
1116 * setting XPT_CLOSE, enqueuing, and letting a thread pick it up to do
1117 * the close.  In the case there are no such other threads,
1118 * threads running, svc_clean_up_xprts() does a simple version of a
1119 * server's main event loop, and in the case where there are other
1120 * threads, we may need to wait a little while and then check again to
1121 * see if they're done.
1122 */
1123void svc_xprt_destroy_all(struct svc_serv *serv, struct net *net)
1124{
1125	int delay = 0;
1126
1127	while (svc_close_list(serv, &serv->sv_permsocks, net) +
1128	       svc_close_list(serv, &serv->sv_tempsocks, net)) {
1129
1130		svc_clean_up_xprts(serv, net);
1131		msleep(delay++);
1132	}
1133}
1134EXPORT_SYMBOL_GPL(svc_xprt_destroy_all);
1135
1136/*
1137 * Handle defer and revisit of requests
1138 */
1139
1140static void svc_revisit(struct cache_deferred_req *dreq, int too_many)
1141{
1142	struct svc_deferred_req *dr =
1143		container_of(dreq, struct svc_deferred_req, handle);
1144	struct svc_xprt *xprt = dr->xprt;
1145
1146	spin_lock(&xprt->xpt_lock);
1147	set_bit(XPT_DEFERRED, &xprt->xpt_flags);
1148	if (too_many || test_bit(XPT_DEAD, &xprt->xpt_flags)) {
1149		spin_unlock(&xprt->xpt_lock);
1150		trace_svc_defer_drop(dr);
1151		free_deferred(xprt, dr);
1152		svc_xprt_put(xprt);
 
1153		return;
1154	}
1155	dr->xprt = NULL;
1156	list_add(&dr->handle.recent, &xprt->xpt_deferred);
1157	spin_unlock(&xprt->xpt_lock);
1158	trace_svc_defer_queue(dr);
1159	svc_xprt_enqueue(xprt);
1160	svc_xprt_put(xprt);
1161}
1162
1163/*
1164 * Save the request off for later processing. The request buffer looks
1165 * like this:
1166 *
1167 * <xprt-header><rpc-header><rpc-pagelist><rpc-tail>
1168 *
1169 * This code can only handle requests that consist of an xprt-header
1170 * and rpc-header.
1171 */
1172static struct cache_deferred_req *svc_defer(struct cache_req *req)
1173{
1174	struct svc_rqst *rqstp = container_of(req, struct svc_rqst, rq_chandle);
1175	struct svc_deferred_req *dr;
1176
1177	if (rqstp->rq_arg.page_len || !test_bit(RQ_USEDEFERRAL, &rqstp->rq_flags))
1178		return NULL; /* if more than a page, give up FIXME */
1179	if (rqstp->rq_deferred) {
1180		dr = rqstp->rq_deferred;
1181		rqstp->rq_deferred = NULL;
1182	} else {
1183		size_t skip;
1184		size_t size;
1185		/* FIXME maybe discard if size too large */
1186		size = sizeof(struct svc_deferred_req) + rqstp->rq_arg.len;
1187		dr = kmalloc(size, GFP_KERNEL);
1188		if (dr == NULL)
1189			return NULL;
1190
1191		dr->handle.owner = rqstp->rq_server;
1192		dr->prot = rqstp->rq_prot;
1193		memcpy(&dr->addr, &rqstp->rq_addr, rqstp->rq_addrlen);
1194		dr->addrlen = rqstp->rq_addrlen;
1195		dr->daddr = rqstp->rq_daddr;
1196		dr->argslen = rqstp->rq_arg.len >> 2;
 
1197
1198		/* back up head to the start of the buffer and copy */
1199		skip = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len;
1200		memcpy(dr->args, rqstp->rq_arg.head[0].iov_base - skip,
1201		       dr->argslen << 2);
1202	}
1203	dr->xprt_ctxt = rqstp->rq_xprt_ctxt;
1204	rqstp->rq_xprt_ctxt = NULL;
1205	trace_svc_defer(rqstp);
1206	svc_xprt_get(rqstp->rq_xprt);
1207	dr->xprt = rqstp->rq_xprt;
1208	set_bit(RQ_DROPME, &rqstp->rq_flags);
1209
1210	dr->handle.revisit = svc_revisit;
1211	return &dr->handle;
1212}
1213
1214/*
1215 * recv data from a deferred request into an active one
1216 */
1217static noinline int svc_deferred_recv(struct svc_rqst *rqstp)
1218{
1219	struct svc_deferred_req *dr = rqstp->rq_deferred;
1220
1221	trace_svc_defer_recv(dr);
1222
1223	/* setup iov_base past transport header */
1224	rqstp->rq_arg.head[0].iov_base = dr->args;
1225	/* The iov_len does not include the transport header bytes */
1226	rqstp->rq_arg.head[0].iov_len = dr->argslen << 2;
1227	rqstp->rq_arg.page_len = 0;
1228	/* The rq_arg.len includes the transport header bytes */
1229	rqstp->rq_arg.len     = dr->argslen << 2;
1230	rqstp->rq_prot        = dr->prot;
1231	memcpy(&rqstp->rq_addr, &dr->addr, dr->addrlen);
1232	rqstp->rq_addrlen     = dr->addrlen;
1233	/* Save off transport header len in case we get deferred again */
 
1234	rqstp->rq_daddr       = dr->daddr;
1235	rqstp->rq_respages    = rqstp->rq_pages;
1236	rqstp->rq_xprt_ctxt   = dr->xprt_ctxt;
1237
1238	dr->xprt_ctxt = NULL;
1239	svc_xprt_received(rqstp->rq_xprt);
1240	return dr->argslen << 2;
1241}
1242
1243
1244static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt)
1245{
1246	struct svc_deferred_req *dr = NULL;
1247
1248	if (!test_bit(XPT_DEFERRED, &xprt->xpt_flags))
1249		return NULL;
1250	spin_lock(&xprt->xpt_lock);
1251	if (!list_empty(&xprt->xpt_deferred)) {
1252		dr = list_entry(xprt->xpt_deferred.next,
1253				struct svc_deferred_req,
1254				handle.recent);
1255		list_del_init(&dr->handle.recent);
1256	} else
1257		clear_bit(XPT_DEFERRED, &xprt->xpt_flags);
1258	spin_unlock(&xprt->xpt_lock);
1259	return dr;
1260}
1261
1262/**
1263 * svc_find_xprt - find an RPC transport instance
1264 * @serv: pointer to svc_serv to search
1265 * @xcl_name: C string containing transport's class name
1266 * @net: owner net pointer
1267 * @af: Address family of transport's local address
1268 * @port: transport's IP port number
1269 *
1270 * Return the transport instance pointer for the endpoint accepting
1271 * connections/peer traffic from the specified transport class,
1272 * address family and port.
1273 *
1274 * Specifying 0 for the address family or port is effectively a
1275 * wild-card, and will result in matching the first transport in the
1276 * service's list that has a matching class name.
1277 */
1278struct svc_xprt *svc_find_xprt(struct svc_serv *serv, const char *xcl_name,
1279			       struct net *net, const sa_family_t af,
1280			       const unsigned short port)
1281{
1282	struct svc_xprt *xprt;
1283	struct svc_xprt *found = NULL;
1284
1285	/* Sanity check the args */
1286	if (serv == NULL || xcl_name == NULL)
1287		return found;
1288
1289	spin_lock_bh(&serv->sv_lock);
1290	list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1291		if (xprt->xpt_net != net)
1292			continue;
1293		if (strcmp(xprt->xpt_class->xcl_name, xcl_name))
1294			continue;
1295		if (af != AF_UNSPEC && af != xprt->xpt_local.ss_family)
1296			continue;
1297		if (port != 0 && port != svc_xprt_local_port(xprt))
1298			continue;
1299		found = xprt;
1300		svc_xprt_get(xprt);
1301		break;
1302	}
1303	spin_unlock_bh(&serv->sv_lock);
1304	return found;
1305}
1306EXPORT_SYMBOL_GPL(svc_find_xprt);
1307
1308static int svc_one_xprt_name(const struct svc_xprt *xprt,
1309			     char *pos, int remaining)
1310{
1311	int len;
1312
1313	len = snprintf(pos, remaining, "%s %u\n",
1314			xprt->xpt_class->xcl_name,
1315			svc_xprt_local_port(xprt));
1316	if (len >= remaining)
1317		return -ENAMETOOLONG;
1318	return len;
1319}
1320
1321/**
1322 * svc_xprt_names - format a buffer with a list of transport names
1323 * @serv: pointer to an RPC service
1324 * @buf: pointer to a buffer to be filled in
1325 * @buflen: length of buffer to be filled in
1326 *
1327 * Fills in @buf with a string containing a list of transport names,
1328 * each name terminated with '\n'.
1329 *
1330 * Returns positive length of the filled-in string on success; otherwise
1331 * a negative errno value is returned if an error occurs.
1332 */
1333int svc_xprt_names(struct svc_serv *serv, char *buf, const int buflen)
1334{
1335	struct svc_xprt *xprt;
1336	int len, totlen;
1337	char *pos;
1338
1339	/* Sanity check args */
1340	if (!serv)
1341		return 0;
1342
1343	spin_lock_bh(&serv->sv_lock);
1344
1345	pos = buf;
1346	totlen = 0;
1347	list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1348		len = svc_one_xprt_name(xprt, pos, buflen - totlen);
1349		if (len < 0) {
1350			*buf = '\0';
1351			totlen = len;
1352		}
1353		if (len <= 0)
1354			break;
1355
1356		pos += len;
1357		totlen += len;
1358	}
1359
1360	spin_unlock_bh(&serv->sv_lock);
1361	return totlen;
1362}
1363EXPORT_SYMBOL_GPL(svc_xprt_names);
1364
 
1365/*----------------------------------------------------------------------------*/
1366
1367static void *svc_pool_stats_start(struct seq_file *m, loff_t *pos)
1368{
1369	unsigned int pidx = (unsigned int)*pos;
1370	struct svc_info *si = m->private;
1371
1372	dprintk("svc_pool_stats_start, *pidx=%u\n", pidx);
1373
1374	mutex_lock(si->mutex);
1375
1376	if (!pidx)
1377		return SEQ_START_TOKEN;
1378	if (!si->serv)
1379		return NULL;
1380	return pidx > si->serv->sv_nrpools ? NULL
1381		: &si->serv->sv_pools[pidx - 1];
1382}
1383
1384static void *svc_pool_stats_next(struct seq_file *m, void *p, loff_t *pos)
1385{
1386	struct svc_pool *pool = p;
1387	struct svc_info *si = m->private;
1388	struct svc_serv *serv = si->serv;
1389
1390	dprintk("svc_pool_stats_next, *pos=%llu\n", *pos);
1391
1392	if (!serv) {
1393		pool = NULL;
1394	} else if (p == SEQ_START_TOKEN) {
1395		pool = &serv->sv_pools[0];
1396	} else {
1397		unsigned int pidx = (pool - &serv->sv_pools[0]);
1398		if (pidx < serv->sv_nrpools-1)
1399			pool = &serv->sv_pools[pidx+1];
1400		else
1401			pool = NULL;
1402	}
1403	++*pos;
1404	return pool;
1405}
1406
1407static void svc_pool_stats_stop(struct seq_file *m, void *p)
1408{
1409	struct svc_info *si = m->private;
1410
1411	mutex_unlock(si->mutex);
1412}
1413
1414static int svc_pool_stats_show(struct seq_file *m, void *p)
1415{
1416	struct svc_pool *pool = p;
1417
1418	if (p == SEQ_START_TOKEN) {
1419		seq_puts(m, "# pool packets-arrived sockets-enqueued threads-woken threads-timedout\n");
1420		return 0;
1421	}
1422
1423	seq_printf(m, "%u %llu %llu %llu 0\n",
1424		   pool->sp_id,
1425		   percpu_counter_sum_positive(&pool->sp_messages_arrived),
1426		   percpu_counter_sum_positive(&pool->sp_sockets_queued),
1427		   percpu_counter_sum_positive(&pool->sp_threads_woken));
 
1428
1429	return 0;
1430}
1431
1432static const struct seq_operations svc_pool_stats_seq_ops = {
1433	.start	= svc_pool_stats_start,
1434	.next	= svc_pool_stats_next,
1435	.stop	= svc_pool_stats_stop,
1436	.show	= svc_pool_stats_show,
1437};
1438
1439int svc_pool_stats_open(struct svc_info *info, struct file *file)
1440{
1441	struct seq_file *seq;
1442	int err;
1443
1444	err = seq_open(file, &svc_pool_stats_seq_ops);
1445	if (err)
1446		return err;
1447	seq = file->private_data;
1448	seq->private = info;
1449
1450	return 0;
1451}
1452EXPORT_SYMBOL(svc_pool_stats_open);
1453
1454/*----------------------------------------------------------------------------*/