1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * net/sunrpc/cache.c
   4 *
   5 * Generic code for various authentication-related caches
   6 * used by sunrpc clients and servers.
   7 *
   8 * Copyright (C) 2002 Neil Brown <neilb@cse.unsw.edu.au>
 
 
 
   9 */
  10
  11#include <linux/types.h>
  12#include <linux/fs.h>
  13#include <linux/file.h>
  14#include <linux/slab.h>
  15#include <linux/signal.h>
  16#include <linux/sched.h>
  17#include <linux/kmod.h>
  18#include <linux/list.h>
  19#include <linux/module.h>
  20#include <linux/ctype.h>
  21#include <linux/string_helpers.h>
  22#include <linux/uaccess.h>
  23#include <linux/poll.h>
  24#include <linux/seq_file.h>
  25#include <linux/proc_fs.h>
  26#include <linux/net.h>
  27#include <linux/workqueue.h>
  28#include <linux/mutex.h>
  29#include <linux/pagemap.h>
  30#include <asm/ioctls.h>
  31#include <linux/sunrpc/types.h>
  32#include <linux/sunrpc/cache.h>
  33#include <linux/sunrpc/stats.h>
  34#include <linux/sunrpc/rpc_pipe_fs.h>
  35#include <trace/events/sunrpc.h>
  36
  37#include "netns.h"
  38#include "fail.h"
  39
  40#define	 RPCDBG_FACILITY RPCDBG_CACHE
  41
  42static bool cache_defer_req(struct cache_req *req, struct cache_head *item);
  43static void cache_revisit_request(struct cache_head *item);
  44
  45static void cache_init(struct cache_head *h, struct cache_detail *detail)
  46{
  47	time64_t now = seconds_since_boot();
  48	INIT_HLIST_NODE(&h->cache_list);
  49	h->flags = 0;
  50	kref_init(&h->ref);
  51	h->expiry_time = now + CACHE_NEW_EXPIRY;
  52	if (now <= detail->flush_time)
  53		/* ensure it isn't already expired */
  54		now = detail->flush_time + 1;
  55	h->last_refresh = now;
  56}
  57
  58static void cache_fresh_unlocked(struct cache_head *head,
  59				struct cache_detail *detail);
  60
  61static struct cache_head *sunrpc_cache_find_rcu(struct cache_detail *detail,
  62						struct cache_head *key,
  63						int hash)
  64{
  65	struct hlist_head *head = &detail->hash_table[hash];
  66	struct cache_head *tmp;
  67
  68	rcu_read_lock();
  69	hlist_for_each_entry_rcu(tmp, head, cache_list) {
  70		if (!detail->match(tmp, key))
  71			continue;
  72		if (test_bit(CACHE_VALID, &tmp->flags) &&
  73		    cache_is_expired(detail, tmp))
  74			continue;
  75		tmp = cache_get_rcu(tmp);
  76		rcu_read_unlock();
  77		return tmp;
  78	}
  79	rcu_read_unlock();
  80	return NULL;
  81}
  82
  83static void sunrpc_begin_cache_remove_entry(struct cache_head *ch,
  84					    struct cache_detail *cd)
  85{
  86	/* Must be called under cd->hash_lock */
  87	hlist_del_init_rcu(&ch->cache_list);
  88	set_bit(CACHE_CLEANED, &ch->flags);
  89	cd->entries --;
  90}
  91
  92static void sunrpc_end_cache_remove_entry(struct cache_head *ch,
  93					  struct cache_detail *cd)
  94{
  95	cache_fresh_unlocked(ch, cd);
  96	cache_put(ch, cd);
  97}
  98
  99static struct cache_head *sunrpc_cache_add_entry(struct cache_detail *detail,
 100						 struct cache_head *key,
 101						 int hash)
 102{
 103	struct cache_head *new, *tmp, *freeme = NULL;
 104	struct hlist_head *head = &detail->hash_table[hash];
 
 
 
 
 
 
 
 
 
 105
 106	new = detail->alloc();
 107	if (!new)
 108		return NULL;
 109	/* must fully initialise 'new', else
 110	 * we might get lose if we need to
 111	 * cache_put it soon.
 112	 */
 113	cache_init(new, detail);
 114	detail->init(new, key);
 115
 116	spin_lock(&detail->hash_lock);
 117
 118	/* check if entry appeared while we slept */
 119	hlist_for_each_entry_rcu(tmp, head, cache_list,
 120				 lockdep_is_held(&detail->hash_lock)) {
 121		if (!detail->match(tmp, key))
 122			continue;
 123		if (test_bit(CACHE_VALID, &tmp->flags) &&
 124		    cache_is_expired(detail, tmp)) {
 125			sunrpc_begin_cache_remove_entry(tmp, detail);
 126			trace_cache_entry_expired(detail, tmp);
 127			freeme = tmp;
 128			break;
 
 
 
 
 129		}
 130		cache_get(tmp);
 131		spin_unlock(&detail->hash_lock);
 132		cache_put(new, detail);
 133		return tmp;
 134	}
 135
 136	hlist_add_head_rcu(&new->cache_list, head);
 137	detail->entries++;
 138	cache_get(new);
 139	spin_unlock(&detail->hash_lock);
 140
 141	if (freeme)
 142		sunrpc_end_cache_remove_entry(freeme, detail);
 143	return new;
 144}
 
 145
 146struct cache_head *sunrpc_cache_lookup_rcu(struct cache_detail *detail,
 147					   struct cache_head *key, int hash)
 148{
 149	struct cache_head *ret;
 150
 151	ret = sunrpc_cache_find_rcu(detail, key, hash);
 152	if (ret)
 153		return ret;
 154	/* Didn't find anything, insert an empty entry */
 155	return sunrpc_cache_add_entry(detail, key, hash);
 156}
 157EXPORT_SYMBOL_GPL(sunrpc_cache_lookup_rcu);
 158
 159static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch);
 160
 161static void cache_fresh_locked(struct cache_head *head, time64_t expiry,
 162			       struct cache_detail *detail)
 163{
 164	time64_t now = seconds_since_boot();
 165	if (now <= detail->flush_time)
 166		/* ensure it isn't immediately treated as expired */
 167		now = detail->flush_time + 1;
 168	head->expiry_time = expiry;
 169	head->last_refresh = now;
 170	smp_wmb(); /* paired with smp_rmb() in cache_is_valid() */
 171	set_bit(CACHE_VALID, &head->flags);
 172}
 173
 174static void cache_fresh_unlocked(struct cache_head *head,
 175				 struct cache_detail *detail)
 176{
 177	if (test_and_clear_bit(CACHE_PENDING, &head->flags)) {
 178		cache_revisit_request(head);
 179		cache_dequeue(detail, head);
 180	}
 181}
 182
 183static void cache_make_negative(struct cache_detail *detail,
 184				struct cache_head *h)
 185{
 186	set_bit(CACHE_NEGATIVE, &h->flags);
 187	trace_cache_entry_make_negative(detail, h);
 188}
 189
 190static void cache_entry_update(struct cache_detail *detail,
 191			       struct cache_head *h,
 192			       struct cache_head *new)
 193{
 194	if (!test_bit(CACHE_NEGATIVE, &new->flags)) {
 195		detail->update(h, new);
 196		trace_cache_entry_update(detail, h);
 197	} else {
 198		cache_make_negative(detail, h);
 199	}
 200}
 201
 202struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
 203				       struct cache_head *new, struct cache_head *old, int hash)
 204{
 205	/* The 'old' entry is to be replaced by 'new'.
 206	 * If 'old' is not VALID, we update it directly,
 207	 * otherwise we need to replace it
 208	 */
 
 209	struct cache_head *tmp;
 210
 211	if (!test_bit(CACHE_VALID, &old->flags)) {
 212		spin_lock(&detail->hash_lock);
 213		if (!test_bit(CACHE_VALID, &old->flags)) {
 214			cache_entry_update(detail, old, new);
 215			cache_fresh_locked(old, new->expiry_time, detail);
 216			spin_unlock(&detail->hash_lock);
 
 
 
 217			cache_fresh_unlocked(old, detail);
 218			return old;
 219		}
 220		spin_unlock(&detail->hash_lock);
 221	}
 222	/* We need to insert a new entry */
 223	tmp = detail->alloc();
 224	if (!tmp) {
 225		cache_put(old, detail);
 226		return NULL;
 227	}
 228	cache_init(tmp, detail);
 229	detail->init(tmp, old);
 
 230
 231	spin_lock(&detail->hash_lock);
 232	cache_entry_update(detail, tmp, new);
 233	hlist_add_head(&tmp->cache_list, &detail->hash_table[hash]);
 
 
 
 
 234	detail->entries++;
 235	cache_get(tmp);
 236	cache_fresh_locked(tmp, new->expiry_time, detail);
 237	cache_fresh_locked(old, 0, detail);
 238	spin_unlock(&detail->hash_lock);
 239	cache_fresh_unlocked(tmp, detail);
 240	cache_fresh_unlocked(old, detail);
 241	cache_put(old, detail);
 242	return tmp;
 243}
 244EXPORT_SYMBOL_GPL(sunrpc_cache_update);
 245
 246static inline int cache_is_valid(struct cache_head *h)
 
 
 
 
 
 
 
 247{
 248	if (!test_bit(CACHE_VALID, &h->flags))
 249		return -EAGAIN;
 250	else {
 251		/* entry is valid */
 252		if (test_bit(CACHE_NEGATIVE, &h->flags))
 253			return -ENOENT;
 254		else {
 255			/*
 256			 * In combination with write barrier in
 257			 * sunrpc_cache_update, ensures that anyone
 258			 * using the cache entry after this sees the
 259			 * updated contents:
 260			 */
 261			smp_rmb();
 262			return 0;
 263		}
 264	}
 265}
 266
 267static int try_to_negate_entry(struct cache_detail *detail, struct cache_head *h)
 268{
 269	int rv;
 270
 271	spin_lock(&detail->hash_lock);
 272	rv = cache_is_valid(h);
 273	if (rv == -EAGAIN) {
 274		cache_make_negative(detail, h);
 275		cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY,
 276				   detail);
 277		rv = -ENOENT;
 278	}
 279	spin_unlock(&detail->hash_lock);
 
 
 280	cache_fresh_unlocked(h, detail);
 281	return rv;
 282}
 283
 284/*
 285 * This is the generic cache management routine for all
 286 * the authentication caches.
 287 * It checks the currency of a cache item and will (later)
 288 * initiate an upcall to fill it if needed.
 289 *
 290 *
 291 * Returns 0 if the cache_head can be used, or cache_puts it and returns
 292 * -EAGAIN if upcall is pending and request has been queued
 293 * -ETIMEDOUT if upcall failed or request could not be queue or
 294 *           upcall completed but item is still invalid (implying that
 295 *           the cache item has been replaced with a newer one).
 296 * -ENOENT if cache entry was negative
 297 */
 298int cache_check(struct cache_detail *detail,
 299		    struct cache_head *h, struct cache_req *rqstp)
 300{
 301	int rv;
 302	time64_t refresh_age, age;
 303
 304	/* First decide return status as best we can */
 305	rv = cache_is_valid(h);
 306
 307	/* now see if we want to start an upcall */
 308	refresh_age = (h->expiry_time - h->last_refresh);
 309	age = seconds_since_boot() - h->last_refresh;
 310
 311	if (rqstp == NULL) {
 312		if (rv == -EAGAIN)
 313			rv = -ENOENT;
 314	} else if (rv == -EAGAIN ||
 315		   (h->expiry_time != 0 && age > refresh_age/2)) {
 316		dprintk("RPC:       Want update, refage=%lld, age=%lld\n",
 317				refresh_age, age);
 318		switch (detail->cache_upcall(detail, h)) {
 319		case -EINVAL:
 320			rv = try_to_negate_entry(detail, h);
 321			break;
 322		case -EAGAIN:
 323			cache_fresh_unlocked(h, detail);
 324			break;
 
 
 
 
 
 325		}
 326	}
 327
 328	if (rv == -EAGAIN) {
 329		if (!cache_defer_req(rqstp, h)) {
 330			/*
 331			 * Request was not deferred; handle it as best
 332			 * we can ourselves:
 333			 */
 334			rv = cache_is_valid(h);
 335			if (rv == -EAGAIN)
 336				rv = -ETIMEDOUT;
 337		}
 338	}
 339	if (rv)
 340		cache_put(h, detail);
 341	return rv;
 342}
 343EXPORT_SYMBOL_GPL(cache_check);
 344
 345/*
 346 * caches need to be periodically cleaned.
 347 * For this we maintain a list of cache_detail and
 348 * a current pointer into that list and into the table
 349 * for that entry.
 350 *
 351 * Each time cache_clean is called it finds the next non-empty entry
 352 * in the current table and walks the list in that entry
 353 * looking for entries that can be removed.
 354 *
 355 * An entry gets removed if:
 356 * - The expiry is before current time
 357 * - The last_refresh time is before the flush_time for that cache
 358 *
 359 * later we might drop old entries with non-NEVER expiry if that table
 360 * is getting 'full' for some definition of 'full'
 361 *
 362 * The question of "how often to scan a table" is an interesting one
 363 * and is answered in part by the use of the "nextcheck" field in the
 364 * cache_detail.
 365 * When a scan of a table begins, the nextcheck field is set to a time
 366 * that is well into the future.
 367 * While scanning, if an expiry time is found that is earlier than the
 368 * current nextcheck time, nextcheck is set to that expiry time.
 369 * If the flush_time is ever set to a time earlier than the nextcheck
 370 * time, the nextcheck time is then set to that flush_time.
 371 *
 372 * A table is then only scanned if the current time is at least
 373 * the nextcheck time.
 374 *
 375 */
 376
 377static LIST_HEAD(cache_list);
 378static DEFINE_SPINLOCK(cache_list_lock);
 379static struct cache_detail *current_detail;
 380static int current_index;
 381
 382static void do_cache_clean(struct work_struct *work);
 383static struct delayed_work cache_cleaner;
 384
 385void sunrpc_init_cache_detail(struct cache_detail *cd)
 386{
 387	spin_lock_init(&cd->hash_lock);
 388	INIT_LIST_HEAD(&cd->queue);
 389	spin_lock(&cache_list_lock);
 390	cd->nextcheck = 0;
 391	cd->entries = 0;
 392	atomic_set(&cd->writers, 0);
 393	cd->last_close = 0;
 394	cd->last_warn = -1;
 395	list_add(&cd->others, &cache_list);
 396	spin_unlock(&cache_list_lock);
 397
 398	/* start the cleaning process */
 399	queue_delayed_work(system_power_efficient_wq, &cache_cleaner, 0);
 400}
 401EXPORT_SYMBOL_GPL(sunrpc_init_cache_detail);
 402
 403void sunrpc_destroy_cache_detail(struct cache_detail *cd)
 404{
 405	cache_purge(cd);
 406	spin_lock(&cache_list_lock);
 407	spin_lock(&cd->hash_lock);
 
 
 
 
 
 408	if (current_detail == cd)
 409		current_detail = NULL;
 410	list_del_init(&cd->others);
 411	spin_unlock(&cd->hash_lock);
 412	spin_unlock(&cache_list_lock);
 413	if (list_empty(&cache_list)) {
 414		/* module must be being unloaded so its safe to kill the worker */
 415		cancel_delayed_work_sync(&cache_cleaner);
 416	}
 
 
 
 417}
 418EXPORT_SYMBOL_GPL(sunrpc_destroy_cache_detail);
 419
 420/* clean cache tries to find something to clean
 421 * and cleans it.
 422 * It returns 1 if it cleaned something,
 423 *            0 if it didn't find anything this time
 424 *           -1 if it fell off the end of the list.
 425 */
 426static int cache_clean(void)
 427{
 428	int rv = 0;
 429	struct list_head *next;
 430
 431	spin_lock(&cache_list_lock);
 432
 433	/* find a suitable table if we don't already have one */
 434	while (current_detail == NULL ||
 435	    current_index >= current_detail->hash_size) {
 436		if (current_detail)
 437			next = current_detail->others.next;
 438		else
 439			next = cache_list.next;
 440		if (next == &cache_list) {
 441			current_detail = NULL;
 442			spin_unlock(&cache_list_lock);
 443			return -1;
 444		}
 445		current_detail = list_entry(next, struct cache_detail, others);
 446		if (current_detail->nextcheck > seconds_since_boot())
 447			current_index = current_detail->hash_size;
 448		else {
 449			current_index = 0;
 450			current_detail->nextcheck = seconds_since_boot()+30*60;
 451		}
 452	}
 453
 454	/* find a non-empty bucket in the table */
 455	while (current_detail &&
 456	       current_index < current_detail->hash_size &&
 457	       hlist_empty(&current_detail->hash_table[current_index]))
 458		current_index++;
 459
 460	/* find a cleanable entry in the bucket and clean it, or set to next bucket */
 461
 462	if (current_detail && current_index < current_detail->hash_size) {
 463		struct cache_head *ch = NULL;
 464		struct cache_detail *d;
 465		struct hlist_head *head;
 466		struct hlist_node *tmp;
 467
 468		spin_lock(&current_detail->hash_lock);
 469
 470		/* Ok, now to clean this strand */
 471
 472		head = &current_detail->hash_table[current_index];
 473		hlist_for_each_entry_safe(ch, tmp, head, cache_list) {
 474			if (current_detail->nextcheck > ch->expiry_time)
 475				current_detail->nextcheck = ch->expiry_time+1;
 476			if (!cache_is_expired(current_detail, ch))
 477				continue;
 478
 479			sunrpc_begin_cache_remove_entry(ch, current_detail);
 480			trace_cache_entry_expired(current_detail, ch);
 
 481			rv = 1;
 482			break;
 483		}
 484
 485		spin_unlock(&current_detail->hash_lock);
 486		d = current_detail;
 487		if (!ch)
 488			current_index ++;
 489		spin_unlock(&cache_list_lock);
 490		if (ch)
 491			sunrpc_end_cache_remove_entry(ch, d);
 
 
 
 
 492	} else
 493		spin_unlock(&cache_list_lock);
 494
 495	return rv;
 496}
 497
 498/*
 499 * We want to regularly clean the cache, so we need to schedule some work ...
 500 */
 501static void do_cache_clean(struct work_struct *work)
 502{
 503	int delay;
 504
 505	if (list_empty(&cache_list))
 506		return;
 507
 508	if (cache_clean() == -1)
 509		delay = round_jiffies_relative(30*HZ);
 510	else
 511		delay = 5;
 512
 513	queue_delayed_work(system_power_efficient_wq, &cache_cleaner, delay);
 
 
 
 
 514}
 515
 516
 517/*
 518 * Clean all caches promptly.  This just calls cache_clean
 519 * repeatedly until we are sure that every cache has had a chance to
 520 * be fully cleaned
 521 */
 522void cache_flush(void)
 523{
 524	while (cache_clean() != -1)
 525		cond_resched();
 526	while (cache_clean() != -1)
 527		cond_resched();
 528}
 529EXPORT_SYMBOL_GPL(cache_flush);
 530
 531void cache_purge(struct cache_detail *detail)
 532{
 533	struct cache_head *ch = NULL;
 534	struct hlist_head *head = NULL;
 535	int i = 0;
 536
 537	spin_lock(&detail->hash_lock);
 538	if (!detail->entries) {
 539		spin_unlock(&detail->hash_lock);
 540		return;
 541	}
 542
 543	dprintk("RPC: %d entries in %s cache\n", detail->entries, detail->name);
 544	for (i = 0; i < detail->hash_size; i++) {
 545		head = &detail->hash_table[i];
 546		while (!hlist_empty(head)) {
 547			ch = hlist_entry(head->first, struct cache_head,
 548					 cache_list);
 549			sunrpc_begin_cache_remove_entry(ch, detail);
 550			spin_unlock(&detail->hash_lock);
 551			sunrpc_end_cache_remove_entry(ch, detail);
 552			spin_lock(&detail->hash_lock);
 553		}
 554	}
 555	spin_unlock(&detail->hash_lock);
 556}
 557EXPORT_SYMBOL_GPL(cache_purge);
 558
 559
 560/*
 561 * Deferral and Revisiting of Requests.
 562 *
 563 * If a cache lookup finds a pending entry, we
 564 * need to defer the request and revisit it later.
 565 * All deferred requests are stored in a hash table,
 566 * indexed by "struct cache_head *".
 567 * As it may be wasteful to store a whole request
 568 * structure, we allow the request to provide a
 569 * deferred form, which must contain a
 570 * 'struct cache_deferred_req'
 571 * This cache_deferred_req contains a method to allow
 572 * it to be revisited when cache info is available
 573 */
 574
 575#define	DFR_HASHSIZE	(PAGE_SIZE/sizeof(struct list_head))
 576#define	DFR_HASH(item)	((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE)
 577
 578#define	DFR_MAX	300	/* ??? */
 579
 580static DEFINE_SPINLOCK(cache_defer_lock);
 581static LIST_HEAD(cache_defer_list);
 582static struct hlist_head cache_defer_hash[DFR_HASHSIZE];
 583static int cache_defer_cnt;
 584
 585static void __unhash_deferred_req(struct cache_deferred_req *dreq)
 586{
 587	hlist_del_init(&dreq->hash);
 588	if (!list_empty(&dreq->recent)) {
 589		list_del_init(&dreq->recent);
 590		cache_defer_cnt--;
 591	}
 592}
 593
 594static void __hash_deferred_req(struct cache_deferred_req *dreq, struct cache_head *item)
 595{
 596	int hash = DFR_HASH(item);
 597
 598	INIT_LIST_HEAD(&dreq->recent);
 599	hlist_add_head(&dreq->hash, &cache_defer_hash[hash]);
 600}
 601
 602static void setup_deferral(struct cache_deferred_req *dreq,
 603			   struct cache_head *item,
 604			   int count_me)
 605{
 606
 607	dreq->item = item;
 608
 609	spin_lock(&cache_defer_lock);
 610
 611	__hash_deferred_req(dreq, item);
 612
 613	if (count_me) {
 614		cache_defer_cnt++;
 615		list_add(&dreq->recent, &cache_defer_list);
 616	}
 617
 618	spin_unlock(&cache_defer_lock);
 619
 620}
 621
 622struct thread_deferred_req {
 623	struct cache_deferred_req handle;
 624	struct completion completion;
 625};
 626
 627static void cache_restart_thread(struct cache_deferred_req *dreq, int too_many)
 628{
 629	struct thread_deferred_req *dr =
 630		container_of(dreq, struct thread_deferred_req, handle);
 631	complete(&dr->completion);
 632}
 633
 634static void cache_wait_req(struct cache_req *req, struct cache_head *item)
 635{
 636	struct thread_deferred_req sleeper;
 637	struct cache_deferred_req *dreq = &sleeper.handle;
 638
 639	sleeper.completion = COMPLETION_INITIALIZER_ONSTACK(sleeper.completion);
 640	dreq->revisit = cache_restart_thread;
 641
 642	setup_deferral(dreq, item, 0);
 643
 644	if (!test_bit(CACHE_PENDING, &item->flags) ||
 645	    wait_for_completion_interruptible_timeout(
 646		    &sleeper.completion, req->thread_wait) <= 0) {
 647		/* The completion wasn't completed, so we need
 648		 * to clean up
 649		 */
 650		spin_lock(&cache_defer_lock);
 651		if (!hlist_unhashed(&sleeper.handle.hash)) {
 652			__unhash_deferred_req(&sleeper.handle);
 653			spin_unlock(&cache_defer_lock);
 654		} else {
 655			/* cache_revisit_request already removed
 656			 * this from the hash table, but hasn't
 657			 * called ->revisit yet.  It will very soon
 658			 * and we need to wait for it.
 659			 */
 660			spin_unlock(&cache_defer_lock);
 661			wait_for_completion(&sleeper.completion);
 662		}
 663	}
 664}
 665
 666static void cache_limit_defers(void)
 667{
 668	/* Make sure we haven't exceed the limit of allowed deferred
 669	 * requests.
 670	 */
 671	struct cache_deferred_req *discard = NULL;
 672
 673	if (cache_defer_cnt <= DFR_MAX)
 674		return;
 675
 676	spin_lock(&cache_defer_lock);
 677
 678	/* Consider removing either the first or the last */
 679	if (cache_defer_cnt > DFR_MAX) {
 680		if (get_random_u32_below(2))
 681			discard = list_entry(cache_defer_list.next,
 682					     struct cache_deferred_req, recent);
 683		else
 684			discard = list_entry(cache_defer_list.prev,
 685					     struct cache_deferred_req, recent);
 686		__unhash_deferred_req(discard);
 687	}
 688	spin_unlock(&cache_defer_lock);
 689	if (discard)
 690		discard->revisit(discard, 1);
 691}
 692
 693#if IS_ENABLED(CONFIG_FAIL_SUNRPC)
 694static inline bool cache_defer_immediately(void)
 695{
 696	return !fail_sunrpc.ignore_cache_wait &&
 697		should_fail(&fail_sunrpc.attr, 1);
 698}
 699#else
 700static inline bool cache_defer_immediately(void)
 701{
 702	return false;
 703}
 704#endif
 705
 706/* Return true if and only if a deferred request is queued. */
 707static bool cache_defer_req(struct cache_req *req, struct cache_head *item)
 708{
 709	struct cache_deferred_req *dreq;
 710
 711	if (!cache_defer_immediately()) {
 712		cache_wait_req(req, item);
 713		if (!test_bit(CACHE_PENDING, &item->flags))
 714			return false;
 715	}
 716
 717	dreq = req->defer(req);
 718	if (dreq == NULL)
 719		return false;
 720	setup_deferral(dreq, item, 1);
 721	if (!test_bit(CACHE_PENDING, &item->flags))
 722		/* Bit could have been cleared before we managed to
 723		 * set up the deferral, so need to revisit just in case
 724		 */
 725		cache_revisit_request(item);
 726
 727	cache_limit_defers();
 728	return true;
 729}
 730
 731static void cache_revisit_request(struct cache_head *item)
 732{
 733	struct cache_deferred_req *dreq;
 734	struct hlist_node *tmp;
 
 735	int hash = DFR_HASH(item);
 736	LIST_HEAD(pending);
 737
 
 738	spin_lock(&cache_defer_lock);
 739
 740	hlist_for_each_entry_safe(dreq, tmp, &cache_defer_hash[hash], hash)
 741		if (dreq->item == item) {
 742			__unhash_deferred_req(dreq);
 743			list_add(&dreq->recent, &pending);
 744		}
 745
 746	spin_unlock(&cache_defer_lock);
 747
 748	while (!list_empty(&pending)) {
 749		dreq = list_entry(pending.next, struct cache_deferred_req, recent);
 750		list_del_init(&dreq->recent);
 751		dreq->revisit(dreq, 0);
 752	}
 753}
 754
 755void cache_clean_deferred(void *owner)
 756{
 757	struct cache_deferred_req *dreq, *tmp;
 758	LIST_HEAD(pending);
 
 759
 
 760	spin_lock(&cache_defer_lock);
 761
 762	list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) {
 763		if (dreq->owner == owner) {
 764			__unhash_deferred_req(dreq);
 765			list_add(&dreq->recent, &pending);
 766		}
 767	}
 768	spin_unlock(&cache_defer_lock);
 769
 770	while (!list_empty(&pending)) {
 771		dreq = list_entry(pending.next, struct cache_deferred_req, recent);
 772		list_del_init(&dreq->recent);
 773		dreq->revisit(dreq, 1);
 774	}
 775}
 776
 777/*
 778 * communicate with user-space
 779 *
 780 * We have a magic /proc file - /proc/net/rpc/<cachename>/channel.
 781 * On read, you get a full request, or block.
 782 * On write, an update request is processed.
 783 * Poll works if anything to read, and always allows write.
 784 *
 785 * Implemented by linked list of requests.  Each open file has
 786 * a ->private that also exists in this list.  New requests are added
 787 * to the end and may wakeup and preceding readers.
 788 * New readers are added to the head.  If, on read, an item is found with
 789 * CACHE_UPCALLING clear, we free it from the list.
 790 *
 791 */
 792
 793static DEFINE_SPINLOCK(queue_lock);
 
 794
 795struct cache_queue {
 796	struct list_head	list;
 797	int			reader;	/* if 0, then request */
 798};
 799struct cache_request {
 800	struct cache_queue	q;
 801	struct cache_head	*item;
 802	char			* buf;
 803	int			len;
 804	int			readers;
 805};
 806struct cache_reader {
 807	struct cache_queue	q;
 808	int			offset;	/* if non-0, we have a refcnt on next request */
 809};
 810
 811static int cache_request(struct cache_detail *detail,
 812			       struct cache_request *crq)
 813{
 814	char *bp = crq->buf;
 815	int len = PAGE_SIZE;
 816
 817	detail->cache_request(detail, crq->item, &bp, &len);
 818	if (len < 0)
 819		return -E2BIG;
 820	return PAGE_SIZE - len;
 821}
 822
 823static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
 824			  loff_t *ppos, struct cache_detail *cd)
 825{
 826	struct cache_reader *rp = filp->private_data;
 827	struct cache_request *rq;
 828	struct inode *inode = file_inode(filp);
 829	int err;
 830
 831	if (count == 0)
 832		return 0;
 833
 834	inode_lock(inode); /* protect against multiple concurrent
 835			      * readers on this file */
 836 again:
 837	spin_lock(&queue_lock);
 838	/* need to find next request */
 839	while (rp->q.list.next != &cd->queue &&
 840	       list_entry(rp->q.list.next, struct cache_queue, list)
 841	       ->reader) {
 842		struct list_head *next = rp->q.list.next;
 843		list_move(&rp->q.list, next);
 844	}
 845	if (rp->q.list.next == &cd->queue) {
 846		spin_unlock(&queue_lock);
 847		inode_unlock(inode);
 848		WARN_ON_ONCE(rp->offset);
 849		return 0;
 850	}
 851	rq = container_of(rp->q.list.next, struct cache_request, q.list);
 852	WARN_ON_ONCE(rq->q.reader);
 853	if (rp->offset == 0)
 854		rq->readers++;
 855	spin_unlock(&queue_lock);
 856
 857	if (rq->len == 0) {
 858		err = cache_request(cd, rq);
 859		if (err < 0)
 860			goto out;
 861		rq->len = err;
 862	}
 863
 864	if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
 865		err = -EAGAIN;
 866		spin_lock(&queue_lock);
 867		list_move(&rp->q.list, &rq->q.list);
 868		spin_unlock(&queue_lock);
 869	} else {
 870		if (rp->offset + count > rq->len)
 871			count = rq->len - rp->offset;
 872		err = -EFAULT;
 873		if (copy_to_user(buf, rq->buf + rp->offset, count))
 874			goto out;
 875		rp->offset += count;
 876		if (rp->offset >= rq->len) {
 877			rp->offset = 0;
 878			spin_lock(&queue_lock);
 879			list_move(&rp->q.list, &rq->q.list);
 880			spin_unlock(&queue_lock);
 881		}
 882		err = 0;
 883	}
 884 out:
 885	if (rp->offset == 0) {
 886		/* need to release rq */
 887		spin_lock(&queue_lock);
 888		rq->readers--;
 889		if (rq->readers == 0 &&
 890		    !test_bit(CACHE_PENDING, &rq->item->flags)) {
 891			list_del(&rq->q.list);
 892			spin_unlock(&queue_lock);
 893			cache_put(rq->item, cd);
 894			kfree(rq->buf);
 895			kfree(rq);
 896		} else
 897			spin_unlock(&queue_lock);
 898	}
 899	if (err == -EAGAIN)
 900		goto again;
 901	inode_unlock(inode);
 902	return err ? err :  count;
 903}
 904
 905static ssize_t cache_do_downcall(char *kaddr, const char __user *buf,
 906				 size_t count, struct cache_detail *cd)
 907{
 908	ssize_t ret;
 909
 910	if (count == 0)
 911		return -EINVAL;
 912	if (copy_from_user(kaddr, buf, count))
 913		return -EFAULT;
 914	kaddr[count] = '\0';
 915	ret = cd->cache_parse(cd, kaddr, count);
 916	if (!ret)
 917		ret = count;
 918	return ret;
 919}
 920
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 921static ssize_t cache_downcall(struct address_space *mapping,
 922			      const char __user *buf,
 923			      size_t count, struct cache_detail *cd)
 924{
 925	char *write_buf;
 
 926	ssize_t ret = -ENOMEM;
 927
 928	if (count >= 32768) { /* 32k is max userland buffer, lets check anyway */
 929		ret = -EINVAL;
 930		goto out;
 931	}
 932
 933	write_buf = kvmalloc(count + 1, GFP_KERNEL);
 934	if (!write_buf)
 935		goto out;
 936
 937	ret = cache_do_downcall(write_buf, buf, count, cd);
 938	kvfree(write_buf);
 939out:
 
 
 
 
 
 
 940	return ret;
 
 
 941}
 942
 943static ssize_t cache_write(struct file *filp, const char __user *buf,
 944			   size_t count, loff_t *ppos,
 945			   struct cache_detail *cd)
 946{
 947	struct address_space *mapping = filp->f_mapping;
 948	struct inode *inode = file_inode(filp);
 949	ssize_t ret = -EINVAL;
 950
 951	if (!cd->cache_parse)
 952		goto out;
 953
 954	inode_lock(inode);
 955	ret = cache_downcall(mapping, buf, count, cd);
 956	inode_unlock(inode);
 957out:
 958	return ret;
 959}
 960
 961static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
 962
 963static __poll_t cache_poll(struct file *filp, poll_table *wait,
 964			       struct cache_detail *cd)
 965{
 966	__poll_t mask;
 967	struct cache_reader *rp = filp->private_data;
 968	struct cache_queue *cq;
 969
 970	poll_wait(filp, &queue_wait, wait);
 971
 972	/* alway allow write */
 973	mask = EPOLLOUT | EPOLLWRNORM;
 974
 975	if (!rp)
 976		return mask;
 977
 978	spin_lock(&queue_lock);
 979
 980	for (cq= &rp->q; &cq->list != &cd->queue;
 981	     cq = list_entry(cq->list.next, struct cache_queue, list))
 982		if (!cq->reader) {
 983			mask |= EPOLLIN | EPOLLRDNORM;
 984			break;
 985		}
 986	spin_unlock(&queue_lock);
 987	return mask;
 988}
 989
 990static int cache_ioctl(struct inode *ino, struct file *filp,
 991		       unsigned int cmd, unsigned long arg,
 992		       struct cache_detail *cd)
 993{
 994	int len = 0;
 995	struct cache_reader *rp = filp->private_data;
 996	struct cache_queue *cq;
 997
 998	if (cmd != FIONREAD || !rp)
 999		return -EINVAL;
1000
1001	spin_lock(&queue_lock);
1002
1003	/* only find the length remaining in current request,
1004	 * or the length of the next request
1005	 */
1006	for (cq= &rp->q; &cq->list != &cd->queue;
1007	     cq = list_entry(cq->list.next, struct cache_queue, list))
1008		if (!cq->reader) {
1009			struct cache_request *cr =
1010				container_of(cq, struct cache_request, q);
1011			len = cr->len - rp->offset;
1012			break;
1013		}
1014	spin_unlock(&queue_lock);
1015
1016	return put_user(len, (int __user *)arg);
1017}
1018
1019static int cache_open(struct inode *inode, struct file *filp,
1020		      struct cache_detail *cd)
1021{
1022	struct cache_reader *rp = NULL;
1023
1024	if (!cd || !try_module_get(cd->owner))
1025		return -EACCES;
1026	nonseekable_open(inode, filp);
1027	if (filp->f_mode & FMODE_READ) {
1028		rp = kmalloc(sizeof(*rp), GFP_KERNEL);
1029		if (!rp) {
1030			module_put(cd->owner);
1031			return -ENOMEM;
1032		}
1033		rp->offset = 0;
1034		rp->q.reader = 1;
1035
1036		spin_lock(&queue_lock);
1037		list_add(&rp->q.list, &cd->queue);
1038		spin_unlock(&queue_lock);
1039	}
1040	if (filp->f_mode & FMODE_WRITE)
1041		atomic_inc(&cd->writers);
1042	filp->private_data = rp;
1043	return 0;
1044}
1045
1046static int cache_release(struct inode *inode, struct file *filp,
1047			 struct cache_detail *cd)
1048{
1049	struct cache_reader *rp = filp->private_data;
1050
1051	if (rp) {
1052		spin_lock(&queue_lock);
1053		if (rp->offset) {
1054			struct cache_queue *cq;
1055			for (cq= &rp->q; &cq->list != &cd->queue;
1056			     cq = list_entry(cq->list.next, struct cache_queue, list))
1057				if (!cq->reader) {
1058					container_of(cq, struct cache_request, q)
1059						->readers--;
1060					break;
1061				}
1062			rp->offset = 0;
1063		}
1064		list_del(&rp->q.list);
1065		spin_unlock(&queue_lock);
1066
1067		filp->private_data = NULL;
1068		kfree(rp);
1069
1070	}
1071	if (filp->f_mode & FMODE_WRITE) {
1072		atomic_dec(&cd->writers);
1073		cd->last_close = seconds_since_boot();
 
1074	}
1075	module_put(cd->owner);
1076	return 0;
1077}
1078
1079
1080
1081static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch)
1082{
1083	struct cache_queue *cq, *tmp;
1084	struct cache_request *cr;
1085	LIST_HEAD(dequeued);
1086
1087	spin_lock(&queue_lock);
1088	list_for_each_entry_safe(cq, tmp, &detail->queue, list)
1089		if (!cq->reader) {
1090			cr = container_of(cq, struct cache_request, q);
1091			if (cr->item != ch)
1092				continue;
1093			if (test_bit(CACHE_PENDING, &ch->flags))
1094				/* Lost a race and it is pending again */
1095				break;
1096			if (cr->readers != 0)
1097				continue;
1098			list_move(&cr->q.list, &dequeued);
 
 
 
 
 
1099		}
1100	spin_unlock(&queue_lock);
1101	while (!list_empty(&dequeued)) {
1102		cr = list_entry(dequeued.next, struct cache_request, q.list);
1103		list_del(&cr->q.list);
1104		cache_put(cr->item, detail);
1105		kfree(cr->buf);
1106		kfree(cr);
1107	}
1108}
1109
1110/*
1111 * Support routines for text-based upcalls.
1112 * Fields are separated by spaces.
1113 * Fields are either mangled to quote space tab newline slosh with slosh
1114 * or a hexified with a leading \x
1115 * Record is terminated with newline.
1116 *
1117 */
1118
1119void qword_add(char **bpp, int *lp, char *str)
1120{
1121	char *bp = *bpp;
1122	int len = *lp;
1123	int ret;
1124
1125	if (len < 0) return;
1126
1127	ret = string_escape_str(str, bp, len, ESCAPE_OCTAL, "\\ \n\t");
1128	if (ret >= len) {
1129		bp += len;
1130		len = -1;
1131	} else {
1132		bp += ret;
1133		len -= ret;
 
 
 
 
 
 
 
 
 
 
 
 
 
1134		*bp++ = ' ';
1135		len--;
1136	}
1137	*bpp = bp;
1138	*lp = len;
1139}
1140EXPORT_SYMBOL_GPL(qword_add);
1141
1142void qword_addhex(char **bpp, int *lp, char *buf, int blen)
1143{
1144	char *bp = *bpp;
1145	int len = *lp;
1146
1147	if (len < 0) return;
1148
1149	if (len > 2) {
1150		*bp++ = '\\';
1151		*bp++ = 'x';
1152		len -= 2;
1153		while (blen && len >= 2) {
1154			bp = hex_byte_pack(bp, *buf++);
 
 
1155			len -= 2;
1156			blen--;
1157		}
1158	}
1159	if (blen || len<1) len = -1;
1160	else {
1161		*bp++ = ' ';
1162		len--;
1163	}
1164	*bpp = bp;
1165	*lp = len;
1166}
1167EXPORT_SYMBOL_GPL(qword_addhex);
1168
1169static void warn_no_listener(struct cache_detail *detail)
1170{
1171	if (detail->last_warn != detail->last_close) {
1172		detail->last_warn = detail->last_close;
1173		if (detail->warn_no_listener)
1174			detail->warn_no_listener(detail, detail->last_close != 0);
1175	}
1176}
1177
1178static bool cache_listeners_exist(struct cache_detail *detail)
1179{
1180	if (atomic_read(&detail->writers))
1181		return true;
1182	if (detail->last_close == 0)
1183		/* This cache was never opened */
1184		return false;
1185	if (detail->last_close < seconds_since_boot() - 30)
1186		/*
1187		 * We allow for the possibility that someone might
1188		 * restart a userspace daemon without restarting the
1189		 * server; but after 30 seconds, we give up.
1190		 */
1191		 return false;
1192	return true;
1193}
1194
1195/*
1196 * register an upcall request to user-space and queue it up for read() by the
1197 * upcall daemon.
1198 *
1199 * Each request is at most one page long.
1200 */
1201static int cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
 
 
 
 
1202{
 
1203	char *buf;
1204	struct cache_request *crq;
1205	int ret = 0;
 
1206
1207	if (test_bit(CACHE_CLEANED, &h->flags))
1208		/* Too late to make an upcall */
1209		return -EAGAIN;
 
1210
1211	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1212	if (!buf)
1213		return -EAGAIN;
1214
1215	crq = kmalloc(sizeof (*crq), GFP_KERNEL);
1216	if (!crq) {
1217		kfree(buf);
1218		return -EAGAIN;
1219	}
1220
 
 
 
 
 
 
 
 
 
1221	crq->q.reader = 0;
 
1222	crq->buf = buf;
1223	crq->len = 0;
1224	crq->readers = 0;
1225	spin_lock(&queue_lock);
1226	if (test_bit(CACHE_PENDING, &h->flags)) {
1227		crq->item = cache_get(h);
1228		list_add_tail(&crq->q.list, &detail->queue);
1229		trace_cache_entry_upcall(detail, h);
1230	} else
1231		/* Lost a race, no longer PENDING, so don't enqueue */
1232		ret = -EAGAIN;
1233	spin_unlock(&queue_lock);
1234	wake_up(&queue_wait);
1235	if (ret == -EAGAIN) {
1236		kfree(buf);
1237		kfree(crq);
1238	}
1239	return ret;
1240}
1241
1242int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
1243{
1244	if (test_and_set_bit(CACHE_PENDING, &h->flags))
1245		return 0;
1246	return cache_pipe_upcall(detail, h);
1247}
1248EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall);
1249
1250int sunrpc_cache_pipe_upcall_timeout(struct cache_detail *detail,
1251				     struct cache_head *h)
1252{
1253	if (!cache_listeners_exist(detail)) {
1254		warn_no_listener(detail);
1255		trace_cache_entry_no_listener(detail, h);
1256		return -EINVAL;
1257	}
1258	return sunrpc_cache_pipe_upcall(detail, h);
1259}
1260EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall_timeout);
1261
1262/*
1263 * parse a message from user-space and pass it
1264 * to an appropriate cache
1265 * Messages are, like requests, separated into fields by
1266 * spaces and dequotes as \xHEXSTRING or embedded \nnn octal
1267 *
1268 * Message is
1269 *   reply cachename expiry key ... content....
1270 *
1271 * key and content are both parsed by cache
1272 */
1273
 
1274int qword_get(char **bpp, char *dest, int bufsize)
1275{
1276	/* return bytes copied, or -1 on error */
1277	char *bp = *bpp;
1278	int len = 0;
1279
1280	while (*bp == ' ') bp++;
1281
1282	if (bp[0] == '\\' && bp[1] == 'x') {
1283		/* HEX STRING */
1284		bp += 2;
1285		while (len < bufsize - 1) {
1286			int h, l;
1287
1288			h = hex_to_bin(bp[0]);
1289			if (h < 0)
1290				break;
1291
1292			l = hex_to_bin(bp[1]);
1293			if (l < 0)
1294				break;
1295
1296			*dest++ = (h << 4) | l;
1297			bp += 2;
1298			len++;
1299		}
1300	} else {
1301		/* text with \nnn octal quoting */
1302		while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) {
1303			if (*bp == '\\' &&
1304			    isodigit(bp[1]) && (bp[1] <= '3') &&
1305			    isodigit(bp[2]) &&
1306			    isodigit(bp[3])) {
1307				int byte = (*++bp -'0');
1308				bp++;
1309				byte = (byte << 3) | (*bp++ - '0');
1310				byte = (byte << 3) | (*bp++ - '0');
1311				*dest++ = byte;
1312				len++;
1313			} else {
1314				*dest++ = *bp++;
1315				len++;
1316			}
1317		}
1318	}
1319
1320	if (*bp != ' ' && *bp != '\n' && *bp != '\0')
1321		return -1;
1322	while (*bp == ' ') bp++;
1323	*bpp = bp;
1324	*dest = '\0';
1325	return len;
1326}
1327EXPORT_SYMBOL_GPL(qword_get);
1328
1329
1330/*
1331 * support /proc/net/rpc/$CACHENAME/content
1332 * as a seqfile.
1333 * We call ->cache_show passing NULL for the item to
1334 * get a header, then pass each real item in the cache
1335 */
1336
1337static void *__cache_seq_start(struct seq_file *m, loff_t *pos)
 
 
 
 
 
1338{
1339	loff_t n = *pos;
1340	unsigned int hash, entry;
1341	struct cache_head *ch;
1342	struct cache_detail *cd = m->private;
 
1343
 
1344	if (!n--)
1345		return SEQ_START_TOKEN;
1346	hash = n >> 32;
1347	entry = n & ((1LL<<32) - 1);
1348
1349	hlist_for_each_entry_rcu(ch, &cd->hash_table[hash], cache_list)
1350		if (!entry--)
1351			return ch;
1352	n &= ~((1LL<<32) - 1);
1353	do {
1354		hash++;
1355		n += 1LL<<32;
1356	} while(hash < cd->hash_size &&
1357		hlist_empty(&cd->hash_table[hash]));
1358	if (hash >= cd->hash_size)
1359		return NULL;
1360	*pos = n+1;
1361	return hlist_entry_safe(rcu_dereference_raw(
1362				hlist_first_rcu(&cd->hash_table[hash])),
1363				struct cache_head, cache_list);
1364}
1365
1366static void *cache_seq_next(struct seq_file *m, void *p, loff_t *pos)
1367{
1368	struct cache_head *ch = p;
1369	int hash = (*pos >> 32);
1370	struct cache_detail *cd = m->private;
1371
1372	if (p == SEQ_START_TOKEN)
1373		hash = 0;
1374	else if (ch->cache_list.next == NULL) {
1375		hash++;
1376		*pos += 1LL<<32;
1377	} else {
1378		++*pos;
1379		return hlist_entry_safe(rcu_dereference_raw(
1380					hlist_next_rcu(&ch->cache_list)),
1381					struct cache_head, cache_list);
1382	}
1383	*pos &= ~((1LL<<32) - 1);
1384	while (hash < cd->hash_size &&
1385	       hlist_empty(&cd->hash_table[hash])) {
1386		hash++;
1387		*pos += 1LL<<32;
1388	}
1389	if (hash >= cd->hash_size)
1390		return NULL;
1391	++*pos;
1392	return hlist_entry_safe(rcu_dereference_raw(
1393				hlist_first_rcu(&cd->hash_table[hash])),
1394				struct cache_head, cache_list);
1395}
1396
1397void *cache_seq_start_rcu(struct seq_file *m, loff_t *pos)
1398	__acquires(RCU)
1399{
1400	rcu_read_lock();
1401	return __cache_seq_start(m, pos);
1402}
1403EXPORT_SYMBOL_GPL(cache_seq_start_rcu);
1404
1405void *cache_seq_next_rcu(struct seq_file *file, void *p, loff_t *pos)
1406{
1407	return cache_seq_next(file, p, pos);
1408}
1409EXPORT_SYMBOL_GPL(cache_seq_next_rcu);
1410
1411void cache_seq_stop_rcu(struct seq_file *m, void *p)
1412	__releases(RCU)
1413{
1414	rcu_read_unlock();
1415}
1416EXPORT_SYMBOL_GPL(cache_seq_stop_rcu);
1417
1418static int c_show(struct seq_file *m, void *p)
1419{
1420	struct cache_head *cp = p;
1421	struct cache_detail *cd = m->private;
1422
1423	if (p == SEQ_START_TOKEN)
1424		return cd->cache_show(m, cd, NULL);
1425
1426	ifdebug(CACHE)
1427		seq_printf(m, "# expiry=%lld refcnt=%d flags=%lx\n",
1428			   convert_to_wallclock(cp->expiry_time),
1429			   kref_read(&cp->ref), cp->flags);
1430	if (!cache_get_rcu(cp))
1431		return 0;
1432
1433	if (cache_check(cd, cp, NULL))
1434		/* cache_check does a cache_put on failure */
1435		seq_puts(m, "# ");
1436	else {
1437		if (cache_is_expired(cd, cp))
1438			seq_puts(m, "# ");
1439		cache_put(cp, cd);
1440	}
1441
1442	return cd->cache_show(m, cd, cp);
1443}
1444
1445static const struct seq_operations cache_content_op = {
1446	.start	= cache_seq_start_rcu,
1447	.next	= cache_seq_next_rcu,
1448	.stop	= cache_seq_stop_rcu,
1449	.show	= c_show,
1450};
1451
1452static int content_open(struct inode *inode, struct file *file,
1453			struct cache_detail *cd)
1454{
1455	struct seq_file *seq;
1456	int err;
1457
1458	if (!cd || !try_module_get(cd->owner))
1459		return -EACCES;
1460
1461	err = seq_open(file, &cache_content_op);
1462	if (err) {
1463		module_put(cd->owner);
1464		return err;
1465	}
1466
1467	seq = file->private_data;
1468	seq->private = cd;
1469	return 0;
1470}
1471
1472static int content_release(struct inode *inode, struct file *file,
1473		struct cache_detail *cd)
1474{
1475	int ret = seq_release(inode, file);
1476	module_put(cd->owner);
1477	return ret;
1478}
1479
1480static int open_flush(struct inode *inode, struct file *file,
1481			struct cache_detail *cd)
1482{
1483	if (!cd || !try_module_get(cd->owner))
1484		return -EACCES;
1485	return nonseekable_open(inode, file);
1486}
1487
1488static int release_flush(struct inode *inode, struct file *file,
1489			struct cache_detail *cd)
1490{
1491	module_put(cd->owner);
1492	return 0;
1493}
1494
1495static ssize_t read_flush(struct file *file, char __user *buf,
1496			  size_t count, loff_t *ppos,
1497			  struct cache_detail *cd)
1498{
1499	char tbuf[22];
 
1500	size_t len;
1501
1502	len = snprintf(tbuf, sizeof(tbuf), "%llu\n",
1503			convert_to_wallclock(cd->flush_time));
1504	return simple_read_from_buffer(buf, count, ppos, tbuf, len);
 
 
 
 
 
 
 
 
1505}
1506
1507static ssize_t write_flush(struct file *file, const char __user *buf,
1508			   size_t count, loff_t *ppos,
1509			   struct cache_detail *cd)
1510{
1511	char tbuf[20];
1512	char *ep;
1513	time64_t now;
1514
1515	if (*ppos || count > sizeof(tbuf)-1)
1516		return -EINVAL;
1517	if (copy_from_user(tbuf, buf, count))
1518		return -EFAULT;
1519	tbuf[count] = 0;
1520	simple_strtoul(tbuf, &ep, 0);
1521	if (*ep && *ep != '\n')
1522		return -EINVAL;
1523	/* Note that while we check that 'buf' holds a valid number,
1524	 * we always ignore the value and just flush everything.
1525	 * Making use of the number leads to races.
1526	 */
1527
1528	now = seconds_since_boot();
1529	/* Always flush everything, so behave like cache_purge()
1530	 * Do this by advancing flush_time to the current time,
1531	 * or by one second if it has already reached the current time.
1532	 * Newly added cache entries will always have ->last_refresh greater
1533	 * that ->flush_time, so they don't get flushed prematurely.
1534	 */
1535
1536	if (cd->flush_time >= now)
1537		now = cd->flush_time + 1;
1538
1539	cd->flush_time = now;
1540	cd->nextcheck = now;
1541	cache_flush();
1542
1543	if (cd->flush)
1544		cd->flush();
1545
1546	*ppos += count;
1547	return count;
1548}
1549
1550static ssize_t cache_read_procfs(struct file *filp, char __user *buf,
1551				 size_t count, loff_t *ppos)
1552{
1553	struct cache_detail *cd = pde_data(file_inode(filp));
1554
1555	return cache_read(filp, buf, count, ppos, cd);
1556}
1557
1558static ssize_t cache_write_procfs(struct file *filp, const char __user *buf,
1559				  size_t count, loff_t *ppos)
1560{
1561	struct cache_detail *cd = pde_data(file_inode(filp));
1562
1563	return cache_write(filp, buf, count, ppos, cd);
1564}
1565
1566static __poll_t cache_poll_procfs(struct file *filp, poll_table *wait)
1567{
1568	struct cache_detail *cd = pde_data(file_inode(filp));
1569
1570	return cache_poll(filp, wait, cd);
1571}
1572
1573static long cache_ioctl_procfs(struct file *filp,
1574			       unsigned int cmd, unsigned long arg)
1575{
1576	struct inode *inode = file_inode(filp);
1577	struct cache_detail *cd = pde_data(inode);
1578
1579	return cache_ioctl(inode, filp, cmd, arg, cd);
1580}
1581
1582static int cache_open_procfs(struct inode *inode, struct file *filp)
1583{
1584	struct cache_detail *cd = pde_data(inode);
1585
1586	return cache_open(inode, filp, cd);
1587}
1588
1589static int cache_release_procfs(struct inode *inode, struct file *filp)
1590{
1591	struct cache_detail *cd = pde_data(inode);
1592
1593	return cache_release(inode, filp, cd);
1594}
1595
1596static const struct proc_ops cache_channel_proc_ops = {
1597	.proc_read	= cache_read_procfs,
1598	.proc_write	= cache_write_procfs,
1599	.proc_poll	= cache_poll_procfs,
1600	.proc_ioctl	= cache_ioctl_procfs, /* for FIONREAD */
1601	.proc_open	= cache_open_procfs,
1602	.proc_release	= cache_release_procfs,
 
 
1603};
1604
1605static int content_open_procfs(struct inode *inode, struct file *filp)
1606{
1607	struct cache_detail *cd = pde_data(inode);
1608
1609	return content_open(inode, filp, cd);
1610}
1611
1612static int content_release_procfs(struct inode *inode, struct file *filp)
1613{
1614	struct cache_detail *cd = pde_data(inode);
1615
1616	return content_release(inode, filp, cd);
1617}
1618
1619static const struct proc_ops content_proc_ops = {
1620	.proc_open	= content_open_procfs,
1621	.proc_read	= seq_read,
1622	.proc_lseek	= seq_lseek,
1623	.proc_release	= content_release_procfs,
1624};
1625
1626static int open_flush_procfs(struct inode *inode, struct file *filp)
1627{
1628	struct cache_detail *cd = pde_data(inode);
1629
1630	return open_flush(inode, filp, cd);
1631}
1632
1633static int release_flush_procfs(struct inode *inode, struct file *filp)
1634{
1635	struct cache_detail *cd = pde_data(inode);
1636
1637	return release_flush(inode, filp, cd);
1638}
1639
1640static ssize_t read_flush_procfs(struct file *filp, char __user *buf,
1641			    size_t count, loff_t *ppos)
1642{
1643	struct cache_detail *cd = pde_data(file_inode(filp));
1644
1645	return read_flush(filp, buf, count, ppos, cd);
1646}
1647
1648static ssize_t write_flush_procfs(struct file *filp,
1649				  const char __user *buf,
1650				  size_t count, loff_t *ppos)
1651{
1652	struct cache_detail *cd = pde_data(file_inode(filp));
1653
1654	return write_flush(filp, buf, count, ppos, cd);
1655}
1656
1657static const struct proc_ops cache_flush_proc_ops = {
1658	.proc_open	= open_flush_procfs,
1659	.proc_read	= read_flush_procfs,
1660	.proc_write	= write_flush_procfs,
1661	.proc_release	= release_flush_procfs,
 
1662};
1663
1664static void remove_cache_proc_entries(struct cache_detail *cd)
1665{
1666	if (cd->procfs) {
1667		proc_remove(cd->procfs);
1668		cd->procfs = NULL;
1669	}
 
 
 
 
 
 
 
 
 
1670}
1671
 
1672static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1673{
1674	struct proc_dir_entry *p;
1675	struct sunrpc_net *sn;
1676
1677	if (!IS_ENABLED(CONFIG_PROC_FS))
1678		return 0;
1679
1680	sn = net_generic(net, sunrpc_net_id);
1681	cd->procfs = proc_mkdir(cd->name, sn->proc_net_rpc);
1682	if (cd->procfs == NULL)
1683		goto out_nomem;
 
 
1684
1685	p = proc_create_data("flush", S_IFREG | 0600,
1686			     cd->procfs, &cache_flush_proc_ops, cd);
 
 
1687	if (p == NULL)
1688		goto out_nomem;
1689
1690	if (cd->cache_request || cd->cache_parse) {
1691		p = proc_create_data("channel", S_IFREG | 0600, cd->procfs,
1692				     &cache_channel_proc_ops, cd);
 
 
1693		if (p == NULL)
1694			goto out_nomem;
1695	}
1696	if (cd->cache_show) {
1697		p = proc_create_data("content", S_IFREG | 0400, cd->procfs,
1698				     &content_proc_ops, cd);
 
 
1699		if (p == NULL)
1700			goto out_nomem;
1701	}
1702	return 0;
1703out_nomem:
1704	remove_cache_proc_entries(cd);
1705	return -ENOMEM;
1706}
 
 
 
 
 
 
1707
1708void __init cache_initialize(void)
1709{
1710	INIT_DEFERRABLE_WORK(&cache_cleaner, do_cache_clean);
1711}
1712
1713int cache_register_net(struct cache_detail *cd, struct net *net)
1714{
1715	int ret;
1716
1717	sunrpc_init_cache_detail(cd);
1718	ret = create_cache_proc_entries(cd, net);
1719	if (ret)
1720		sunrpc_destroy_cache_detail(cd);
1721	return ret;
1722}
1723EXPORT_SYMBOL_GPL(cache_register_net);
1724
1725void cache_unregister_net(struct cache_detail *cd, struct net *net)
1726{
1727	remove_cache_proc_entries(cd);
1728	sunrpc_destroy_cache_detail(cd);
1729}
1730EXPORT_SYMBOL_GPL(cache_unregister_net);
1731
1732struct cache_detail *cache_create_net(const struct cache_detail *tmpl, struct net *net)
1733{
1734	struct cache_detail *cd;
1735	int i;
1736
1737	cd = kmemdup(tmpl, sizeof(struct cache_detail), GFP_KERNEL);
1738	if (cd == NULL)
1739		return ERR_PTR(-ENOMEM);
1740
1741	cd->hash_table = kcalloc(cd->hash_size, sizeof(struct hlist_head),
1742				 GFP_KERNEL);
1743	if (cd->hash_table == NULL) {
1744		kfree(cd);
1745		return ERR_PTR(-ENOMEM);
1746	}
1747
1748	for (i = 0; i < cd->hash_size; i++)
1749		INIT_HLIST_HEAD(&cd->hash_table[i]);
1750	cd->net = net;
1751	return cd;
1752}
1753EXPORT_SYMBOL_GPL(cache_create_net);
1754
1755void cache_destroy_net(struct cache_detail *cd, struct net *net)
1756{
1757	kfree(cd->hash_table);
1758	kfree(cd);
1759}
1760EXPORT_SYMBOL_GPL(cache_destroy_net);
1761
1762static ssize_t cache_read_pipefs(struct file *filp, char __user *buf,
1763				 size_t count, loff_t *ppos)
1764{
1765	struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1766
1767	return cache_read(filp, buf, count, ppos, cd);
1768}
1769
1770static ssize_t cache_write_pipefs(struct file *filp, const char __user *buf,
1771				  size_t count, loff_t *ppos)
1772{
1773	struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1774
1775	return cache_write(filp, buf, count, ppos, cd);
1776}
1777
1778static __poll_t cache_poll_pipefs(struct file *filp, poll_table *wait)
1779{
1780	struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1781
1782	return cache_poll(filp, wait, cd);
1783}
1784
1785static long cache_ioctl_pipefs(struct file *filp,
1786			      unsigned int cmd, unsigned long arg)
1787{
1788	struct inode *inode = file_inode(filp);
1789	struct cache_detail *cd = RPC_I(inode)->private;
1790
1791	return cache_ioctl(inode, filp, cmd, arg, cd);
1792}
1793
1794static int cache_open_pipefs(struct inode *inode, struct file *filp)
1795{
1796	struct cache_detail *cd = RPC_I(inode)->private;
1797
1798	return cache_open(inode, filp, cd);
1799}
1800
1801static int cache_release_pipefs(struct inode *inode, struct file *filp)
1802{
1803	struct cache_detail *cd = RPC_I(inode)->private;
1804
1805	return cache_release(inode, filp, cd);
1806}
1807
1808const struct file_operations cache_file_operations_pipefs = {
1809	.owner		= THIS_MODULE,
 
1810	.read		= cache_read_pipefs,
1811	.write		= cache_write_pipefs,
1812	.poll		= cache_poll_pipefs,
1813	.unlocked_ioctl	= cache_ioctl_pipefs, /* for FIONREAD */
1814	.open		= cache_open_pipefs,
1815	.release	= cache_release_pipefs,
1816};
1817
1818static int content_open_pipefs(struct inode *inode, struct file *filp)
1819{
1820	struct cache_detail *cd = RPC_I(inode)->private;
1821
1822	return content_open(inode, filp, cd);
1823}
1824
1825static int content_release_pipefs(struct inode *inode, struct file *filp)
1826{
1827	struct cache_detail *cd = RPC_I(inode)->private;
1828
1829	return content_release(inode, filp, cd);
1830}
1831
1832const struct file_operations content_file_operations_pipefs = {
1833	.open		= content_open_pipefs,
1834	.read		= seq_read,
1835	.llseek		= seq_lseek,
1836	.release	= content_release_pipefs,
1837};
1838
1839static int open_flush_pipefs(struct inode *inode, struct file *filp)
1840{
1841	struct cache_detail *cd = RPC_I(inode)->private;
1842
1843	return open_flush(inode, filp, cd);
1844}
1845
1846static int release_flush_pipefs(struct inode *inode, struct file *filp)
1847{
1848	struct cache_detail *cd = RPC_I(inode)->private;
1849
1850	return release_flush(inode, filp, cd);
1851}
1852
1853static ssize_t read_flush_pipefs(struct file *filp, char __user *buf,
1854			    size_t count, loff_t *ppos)
1855{
1856	struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1857
1858	return read_flush(filp, buf, count, ppos, cd);
1859}
1860
1861static ssize_t write_flush_pipefs(struct file *filp,
1862				  const char __user *buf,
1863				  size_t count, loff_t *ppos)
1864{
1865	struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1866
1867	return write_flush(filp, buf, count, ppos, cd);
1868}
1869
1870const struct file_operations cache_flush_operations_pipefs = {
1871	.open		= open_flush_pipefs,
1872	.read		= read_flush_pipefs,
1873	.write		= write_flush_pipefs,
1874	.release	= release_flush_pipefs,
 
1875};
1876
1877int sunrpc_cache_register_pipefs(struct dentry *parent,
1878				 const char *name, umode_t umode,
1879				 struct cache_detail *cd)
1880{
1881	struct dentry *dir = rpc_create_cache_dir(parent, name, umode, cd);
1882	if (IS_ERR(dir))
1883		return PTR_ERR(dir);
1884	cd->pipefs = dir;
1885	return 0;
 
 
 
 
 
 
 
 
1886}
1887EXPORT_SYMBOL_GPL(sunrpc_cache_register_pipefs);
1888
1889void sunrpc_cache_unregister_pipefs(struct cache_detail *cd)
1890{
1891	if (cd->pipefs) {
1892		rpc_remove_cache_dir(cd->pipefs);
1893		cd->pipefs = NULL;
1894	}
1895}
1896EXPORT_SYMBOL_GPL(sunrpc_cache_unregister_pipefs);
1897
1898void sunrpc_cache_unhash(struct cache_detail *cd, struct cache_head *h)
1899{
1900	spin_lock(&cd->hash_lock);
1901	if (!hlist_unhashed(&h->cache_list)){
1902		sunrpc_begin_cache_remove_entry(h, cd);
1903		spin_unlock(&cd->hash_lock);
1904		sunrpc_end_cache_remove_entry(h, cd);
1905	} else
1906		spin_unlock(&cd->hash_lock);
1907}
1908EXPORT_SYMBOL_GPL(sunrpc_cache_unhash);