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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 "netns.h"
36
37#define RPCDBG_FACILITY RPCDBG_CACHE
38
39static bool cache_defer_req(struct cache_req *req, struct cache_head *item);
40static void cache_revisit_request(struct cache_head *item);
41static bool cache_listeners_exist(struct cache_detail *detail);
42
43static void cache_init(struct cache_head *h, struct cache_detail *detail)
44{
45 time_t now = seconds_since_boot();
46 INIT_HLIST_NODE(&h->cache_list);
47 h->flags = 0;
48 kref_init(&h->ref);
49 h->expiry_time = now + CACHE_NEW_EXPIRY;
50 if (now <= detail->flush_time)
51 /* ensure it isn't already expired */
52 now = detail->flush_time + 1;
53 h->last_refresh = now;
54}
55
56static inline int cache_is_valid(struct cache_head *h);
57static void cache_fresh_locked(struct cache_head *head, time_t expiry,
58 struct cache_detail *detail);
59static void cache_fresh_unlocked(struct cache_head *head,
60 struct cache_detail *detail);
61
62static struct cache_head *sunrpc_cache_find_rcu(struct cache_detail *detail,
63 struct cache_head *key,
64 int hash)
65{
66 struct hlist_head *head = &detail->hash_table[hash];
67 struct cache_head *tmp;
68
69 rcu_read_lock();
70 hlist_for_each_entry_rcu(tmp, head, cache_list) {
71 if (detail->match(tmp, key)) {
72 if (cache_is_expired(detail, tmp))
73 continue;
74 tmp = cache_get_rcu(tmp);
75 rcu_read_unlock();
76 return tmp;
77 }
78 }
79 rcu_read_unlock();
80 return NULL;
81}
82
83static struct cache_head *sunrpc_cache_add_entry(struct cache_detail *detail,
84 struct cache_head *key,
85 int hash)
86{
87 struct cache_head *new, *tmp, *freeme = NULL;
88 struct hlist_head *head = &detail->hash_table[hash];
89
90 new = detail->alloc();
91 if (!new)
92 return NULL;
93 /* must fully initialise 'new', else
94 * we might get lose if we need to
95 * cache_put it soon.
96 */
97 cache_init(new, detail);
98 detail->init(new, key);
99
100 spin_lock(&detail->hash_lock);
101
102 /* check if entry appeared while we slept */
103 hlist_for_each_entry_rcu(tmp, head, cache_list) {
104 if (detail->match(tmp, key)) {
105 if (cache_is_expired(detail, tmp)) {
106 hlist_del_init_rcu(&tmp->cache_list);
107 detail->entries --;
108 if (cache_is_valid(tmp) == -EAGAIN)
109 set_bit(CACHE_NEGATIVE, &tmp->flags);
110 cache_fresh_locked(tmp, 0, detail);
111 freeme = tmp;
112 break;
113 }
114 cache_get(tmp);
115 spin_unlock(&detail->hash_lock);
116 cache_put(new, detail);
117 return tmp;
118 }
119 }
120
121 hlist_add_head_rcu(&new->cache_list, head);
122 detail->entries++;
123 cache_get(new);
124 spin_unlock(&detail->hash_lock);
125
126 if (freeme) {
127 cache_fresh_unlocked(freeme, detail);
128 cache_put(freeme, detail);
129 }
130 return new;
131}
132
133struct cache_head *sunrpc_cache_lookup_rcu(struct cache_detail *detail,
134 struct cache_head *key, int hash)
135{
136 struct cache_head *ret;
137
138 ret = sunrpc_cache_find_rcu(detail, key, hash);
139 if (ret)
140 return ret;
141 /* Didn't find anything, insert an empty entry */
142 return sunrpc_cache_add_entry(detail, key, hash);
143}
144EXPORT_SYMBOL_GPL(sunrpc_cache_lookup_rcu);
145
146static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch);
147
148static void cache_fresh_locked(struct cache_head *head, time_t expiry,
149 struct cache_detail *detail)
150{
151 time_t now = seconds_since_boot();
152 if (now <= detail->flush_time)
153 /* ensure it isn't immediately treated as expired */
154 now = detail->flush_time + 1;
155 head->expiry_time = expiry;
156 head->last_refresh = now;
157 smp_wmb(); /* paired with smp_rmb() in cache_is_valid() */
158 set_bit(CACHE_VALID, &head->flags);
159}
160
161static void cache_fresh_unlocked(struct cache_head *head,
162 struct cache_detail *detail)
163{
164 if (test_and_clear_bit(CACHE_PENDING, &head->flags)) {
165 cache_revisit_request(head);
166 cache_dequeue(detail, head);
167 }
168}
169
170struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
171 struct cache_head *new, struct cache_head *old, int hash)
172{
173 /* The 'old' entry is to be replaced by 'new'.
174 * If 'old' is not VALID, we update it directly,
175 * otherwise we need to replace it
176 */
177 struct cache_head *tmp;
178
179 if (!test_bit(CACHE_VALID, &old->flags)) {
180 spin_lock(&detail->hash_lock);
181 if (!test_bit(CACHE_VALID, &old->flags)) {
182 if (test_bit(CACHE_NEGATIVE, &new->flags))
183 set_bit(CACHE_NEGATIVE, &old->flags);
184 else
185 detail->update(old, new);
186 cache_fresh_locked(old, new->expiry_time, detail);
187 spin_unlock(&detail->hash_lock);
188 cache_fresh_unlocked(old, detail);
189 return old;
190 }
191 spin_unlock(&detail->hash_lock);
192 }
193 /* We need to insert a new entry */
194 tmp = detail->alloc();
195 if (!tmp) {
196 cache_put(old, detail);
197 return NULL;
198 }
199 cache_init(tmp, detail);
200 detail->init(tmp, old);
201
202 spin_lock(&detail->hash_lock);
203 if (test_bit(CACHE_NEGATIVE, &new->flags))
204 set_bit(CACHE_NEGATIVE, &tmp->flags);
205 else
206 detail->update(tmp, new);
207 hlist_add_head(&tmp->cache_list, &detail->hash_table[hash]);
208 detail->entries++;
209 cache_get(tmp);
210 cache_fresh_locked(tmp, new->expiry_time, detail);
211 cache_fresh_locked(old, 0, detail);
212 spin_unlock(&detail->hash_lock);
213 cache_fresh_unlocked(tmp, detail);
214 cache_fresh_unlocked(old, detail);
215 cache_put(old, detail);
216 return tmp;
217}
218EXPORT_SYMBOL_GPL(sunrpc_cache_update);
219
220static int cache_make_upcall(struct cache_detail *cd, struct cache_head *h)
221{
222 if (cd->cache_upcall)
223 return cd->cache_upcall(cd, h);
224 return sunrpc_cache_pipe_upcall(cd, h);
225}
226
227static inline int cache_is_valid(struct cache_head *h)
228{
229 if (!test_bit(CACHE_VALID, &h->flags))
230 return -EAGAIN;
231 else {
232 /* entry is valid */
233 if (test_bit(CACHE_NEGATIVE, &h->flags))
234 return -ENOENT;
235 else {
236 /*
237 * In combination with write barrier in
238 * sunrpc_cache_update, ensures that anyone
239 * using the cache entry after this sees the
240 * updated contents:
241 */
242 smp_rmb();
243 return 0;
244 }
245 }
246}
247
248static int try_to_negate_entry(struct cache_detail *detail, struct cache_head *h)
249{
250 int rv;
251
252 spin_lock(&detail->hash_lock);
253 rv = cache_is_valid(h);
254 if (rv == -EAGAIN) {
255 set_bit(CACHE_NEGATIVE, &h->flags);
256 cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY,
257 detail);
258 rv = -ENOENT;
259 }
260 spin_unlock(&detail->hash_lock);
261 cache_fresh_unlocked(h, detail);
262 return rv;
263}
264
265/*
266 * This is the generic cache management routine for all
267 * the authentication caches.
268 * It checks the currency of a cache item and will (later)
269 * initiate an upcall to fill it if needed.
270 *
271 *
272 * Returns 0 if the cache_head can be used, or cache_puts it and returns
273 * -EAGAIN if upcall is pending and request has been queued
274 * -ETIMEDOUT if upcall failed or request could not be queue or
275 * upcall completed but item is still invalid (implying that
276 * the cache item has been replaced with a newer one).
277 * -ENOENT if cache entry was negative
278 */
279int cache_check(struct cache_detail *detail,
280 struct cache_head *h, struct cache_req *rqstp)
281{
282 int rv;
283 long refresh_age, age;
284
285 /* First decide return status as best we can */
286 rv = cache_is_valid(h);
287
288 /* now see if we want to start an upcall */
289 refresh_age = (h->expiry_time - h->last_refresh);
290 age = seconds_since_boot() - h->last_refresh;
291
292 if (rqstp == NULL) {
293 if (rv == -EAGAIN)
294 rv = -ENOENT;
295 } else if (rv == -EAGAIN ||
296 (h->expiry_time != 0 && age > refresh_age/2)) {
297 dprintk("RPC: Want update, refage=%ld, age=%ld\n",
298 refresh_age, age);
299 if (!test_and_set_bit(CACHE_PENDING, &h->flags)) {
300 switch (cache_make_upcall(detail, h)) {
301 case -EINVAL:
302 rv = try_to_negate_entry(detail, h);
303 break;
304 case -EAGAIN:
305 cache_fresh_unlocked(h, detail);
306 break;
307 }
308 } else if (!cache_listeners_exist(detail))
309 rv = try_to_negate_entry(detail, h);
310 }
311
312 if (rv == -EAGAIN) {
313 if (!cache_defer_req(rqstp, h)) {
314 /*
315 * Request was not deferred; handle it as best
316 * we can ourselves:
317 */
318 rv = cache_is_valid(h);
319 if (rv == -EAGAIN)
320 rv = -ETIMEDOUT;
321 }
322 }
323 if (rv)
324 cache_put(h, detail);
325 return rv;
326}
327EXPORT_SYMBOL_GPL(cache_check);
328
329/*
330 * caches need to be periodically cleaned.
331 * For this we maintain a list of cache_detail and
332 * a current pointer into that list and into the table
333 * for that entry.
334 *
335 * Each time cache_clean is called it finds the next non-empty entry
336 * in the current table and walks the list in that entry
337 * looking for entries that can be removed.
338 *
339 * An entry gets removed if:
340 * - The expiry is before current time
341 * - The last_refresh time is before the flush_time for that cache
342 *
343 * later we might drop old entries with non-NEVER expiry if that table
344 * is getting 'full' for some definition of 'full'
345 *
346 * The question of "how often to scan a table" is an interesting one
347 * and is answered in part by the use of the "nextcheck" field in the
348 * cache_detail.
349 * When a scan of a table begins, the nextcheck field is set to a time
350 * that is well into the future.
351 * While scanning, if an expiry time is found that is earlier than the
352 * current nextcheck time, nextcheck is set to that expiry time.
353 * If the flush_time is ever set to a time earlier than the nextcheck
354 * time, the nextcheck time is then set to that flush_time.
355 *
356 * A table is then only scanned if the current time is at least
357 * the nextcheck time.
358 *
359 */
360
361static LIST_HEAD(cache_list);
362static DEFINE_SPINLOCK(cache_list_lock);
363static struct cache_detail *current_detail;
364static int current_index;
365
366static void do_cache_clean(struct work_struct *work);
367static struct delayed_work cache_cleaner;
368
369void sunrpc_init_cache_detail(struct cache_detail *cd)
370{
371 spin_lock_init(&cd->hash_lock);
372 INIT_LIST_HEAD(&cd->queue);
373 spin_lock(&cache_list_lock);
374 cd->nextcheck = 0;
375 cd->entries = 0;
376 atomic_set(&cd->writers, 0);
377 cd->last_close = 0;
378 cd->last_warn = -1;
379 list_add(&cd->others, &cache_list);
380 spin_unlock(&cache_list_lock);
381
382 /* start the cleaning process */
383 queue_delayed_work(system_power_efficient_wq, &cache_cleaner, 0);
384}
385EXPORT_SYMBOL_GPL(sunrpc_init_cache_detail);
386
387void sunrpc_destroy_cache_detail(struct cache_detail *cd)
388{
389 cache_purge(cd);
390 spin_lock(&cache_list_lock);
391 spin_lock(&cd->hash_lock);
392 if (current_detail == cd)
393 current_detail = NULL;
394 list_del_init(&cd->others);
395 spin_unlock(&cd->hash_lock);
396 spin_unlock(&cache_list_lock);
397 if (list_empty(&cache_list)) {
398 /* module must be being unloaded so its safe to kill the worker */
399 cancel_delayed_work_sync(&cache_cleaner);
400 }
401}
402EXPORT_SYMBOL_GPL(sunrpc_destroy_cache_detail);
403
404/* clean cache tries to find something to clean
405 * and cleans it.
406 * It returns 1 if it cleaned something,
407 * 0 if it didn't find anything this time
408 * -1 if it fell off the end of the list.
409 */
410static int cache_clean(void)
411{
412 int rv = 0;
413 struct list_head *next;
414
415 spin_lock(&cache_list_lock);
416
417 /* find a suitable table if we don't already have one */
418 while (current_detail == NULL ||
419 current_index >= current_detail->hash_size) {
420 if (current_detail)
421 next = current_detail->others.next;
422 else
423 next = cache_list.next;
424 if (next == &cache_list) {
425 current_detail = NULL;
426 spin_unlock(&cache_list_lock);
427 return -1;
428 }
429 current_detail = list_entry(next, struct cache_detail, others);
430 if (current_detail->nextcheck > seconds_since_boot())
431 current_index = current_detail->hash_size;
432 else {
433 current_index = 0;
434 current_detail->nextcheck = seconds_since_boot()+30*60;
435 }
436 }
437
438 /* find a non-empty bucket in the table */
439 while (current_detail &&
440 current_index < current_detail->hash_size &&
441 hlist_empty(¤t_detail->hash_table[current_index]))
442 current_index++;
443
444 /* find a cleanable entry in the bucket and clean it, or set to next bucket */
445
446 if (current_detail && current_index < current_detail->hash_size) {
447 struct cache_head *ch = NULL;
448 struct cache_detail *d;
449 struct hlist_head *head;
450 struct hlist_node *tmp;
451
452 spin_lock(¤t_detail->hash_lock);
453
454 /* Ok, now to clean this strand */
455
456 head = ¤t_detail->hash_table[current_index];
457 hlist_for_each_entry_safe(ch, tmp, head, cache_list) {
458 if (current_detail->nextcheck > ch->expiry_time)
459 current_detail->nextcheck = ch->expiry_time+1;
460 if (!cache_is_expired(current_detail, ch))
461 continue;
462
463 hlist_del_init_rcu(&ch->cache_list);
464 current_detail->entries--;
465 rv = 1;
466 break;
467 }
468
469 spin_unlock(¤t_detail->hash_lock);
470 d = current_detail;
471 if (!ch)
472 current_index ++;
473 spin_unlock(&cache_list_lock);
474 if (ch) {
475 set_bit(CACHE_CLEANED, &ch->flags);
476 cache_fresh_unlocked(ch, d);
477 cache_put(ch, d);
478 }
479 } else
480 spin_unlock(&cache_list_lock);
481
482 return rv;
483}
484
485/*
486 * We want to regularly clean the cache, so we need to schedule some work ...
487 */
488static void do_cache_clean(struct work_struct *work)
489{
490 int delay = 5;
491 if (cache_clean() == -1)
492 delay = round_jiffies_relative(30*HZ);
493
494 if (list_empty(&cache_list))
495 delay = 0;
496
497 if (delay)
498 queue_delayed_work(system_power_efficient_wq,
499 &cache_cleaner, delay);
500}
501
502
503/*
504 * Clean all caches promptly. This just calls cache_clean
505 * repeatedly until we are sure that every cache has had a chance to
506 * be fully cleaned
507 */
508void cache_flush(void)
509{
510 while (cache_clean() != -1)
511 cond_resched();
512 while (cache_clean() != -1)
513 cond_resched();
514}
515EXPORT_SYMBOL_GPL(cache_flush);
516
517void cache_purge(struct cache_detail *detail)
518{
519 struct cache_head *ch = NULL;
520 struct hlist_head *head = NULL;
521 struct hlist_node *tmp = NULL;
522 int i = 0;
523
524 spin_lock(&detail->hash_lock);
525 if (!detail->entries) {
526 spin_unlock(&detail->hash_lock);
527 return;
528 }
529
530 dprintk("RPC: %d entries in %s cache\n", detail->entries, detail->name);
531 for (i = 0; i < detail->hash_size; i++) {
532 head = &detail->hash_table[i];
533 hlist_for_each_entry_safe(ch, tmp, head, cache_list) {
534 hlist_del_init_rcu(&ch->cache_list);
535 detail->entries--;
536
537 set_bit(CACHE_CLEANED, &ch->flags);
538 spin_unlock(&detail->hash_lock);
539 cache_fresh_unlocked(ch, detail);
540 cache_put(ch, detail);
541 spin_lock(&detail->hash_lock);
542 }
543 }
544 spin_unlock(&detail->hash_lock);
545}
546EXPORT_SYMBOL_GPL(cache_purge);
547
548
549/*
550 * Deferral and Revisiting of Requests.
551 *
552 * If a cache lookup finds a pending entry, we
553 * need to defer the request and revisit it later.
554 * All deferred requests are stored in a hash table,
555 * indexed by "struct cache_head *".
556 * As it may be wasteful to store a whole request
557 * structure, we allow the request to provide a
558 * deferred form, which must contain a
559 * 'struct cache_deferred_req'
560 * This cache_deferred_req contains a method to allow
561 * it to be revisited when cache info is available
562 */
563
564#define DFR_HASHSIZE (PAGE_SIZE/sizeof(struct list_head))
565#define DFR_HASH(item) ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE)
566
567#define DFR_MAX 300 /* ??? */
568
569static DEFINE_SPINLOCK(cache_defer_lock);
570static LIST_HEAD(cache_defer_list);
571static struct hlist_head cache_defer_hash[DFR_HASHSIZE];
572static int cache_defer_cnt;
573
574static void __unhash_deferred_req(struct cache_deferred_req *dreq)
575{
576 hlist_del_init(&dreq->hash);
577 if (!list_empty(&dreq->recent)) {
578 list_del_init(&dreq->recent);
579 cache_defer_cnt--;
580 }
581}
582
583static void __hash_deferred_req(struct cache_deferred_req *dreq, struct cache_head *item)
584{
585 int hash = DFR_HASH(item);
586
587 INIT_LIST_HEAD(&dreq->recent);
588 hlist_add_head(&dreq->hash, &cache_defer_hash[hash]);
589}
590
591static void setup_deferral(struct cache_deferred_req *dreq,
592 struct cache_head *item,
593 int count_me)
594{
595
596 dreq->item = item;
597
598 spin_lock(&cache_defer_lock);
599
600 __hash_deferred_req(dreq, item);
601
602 if (count_me) {
603 cache_defer_cnt++;
604 list_add(&dreq->recent, &cache_defer_list);
605 }
606
607 spin_unlock(&cache_defer_lock);
608
609}
610
611struct thread_deferred_req {
612 struct cache_deferred_req handle;
613 struct completion completion;
614};
615
616static void cache_restart_thread(struct cache_deferred_req *dreq, int too_many)
617{
618 struct thread_deferred_req *dr =
619 container_of(dreq, struct thread_deferred_req, handle);
620 complete(&dr->completion);
621}
622
623static void cache_wait_req(struct cache_req *req, struct cache_head *item)
624{
625 struct thread_deferred_req sleeper;
626 struct cache_deferred_req *dreq = &sleeper.handle;
627
628 sleeper.completion = COMPLETION_INITIALIZER_ONSTACK(sleeper.completion);
629 dreq->revisit = cache_restart_thread;
630
631 setup_deferral(dreq, item, 0);
632
633 if (!test_bit(CACHE_PENDING, &item->flags) ||
634 wait_for_completion_interruptible_timeout(
635 &sleeper.completion, req->thread_wait) <= 0) {
636 /* The completion wasn't completed, so we need
637 * to clean up
638 */
639 spin_lock(&cache_defer_lock);
640 if (!hlist_unhashed(&sleeper.handle.hash)) {
641 __unhash_deferred_req(&sleeper.handle);
642 spin_unlock(&cache_defer_lock);
643 } else {
644 /* cache_revisit_request already removed
645 * this from the hash table, but hasn't
646 * called ->revisit yet. It will very soon
647 * and we need to wait for it.
648 */
649 spin_unlock(&cache_defer_lock);
650 wait_for_completion(&sleeper.completion);
651 }
652 }
653}
654
655static void cache_limit_defers(void)
656{
657 /* Make sure we haven't exceed the limit of allowed deferred
658 * requests.
659 */
660 struct cache_deferred_req *discard = NULL;
661
662 if (cache_defer_cnt <= DFR_MAX)
663 return;
664
665 spin_lock(&cache_defer_lock);
666
667 /* Consider removing either the first or the last */
668 if (cache_defer_cnt > DFR_MAX) {
669 if (prandom_u32() & 1)
670 discard = list_entry(cache_defer_list.next,
671 struct cache_deferred_req, recent);
672 else
673 discard = list_entry(cache_defer_list.prev,
674 struct cache_deferred_req, recent);
675 __unhash_deferred_req(discard);
676 }
677 spin_unlock(&cache_defer_lock);
678 if (discard)
679 discard->revisit(discard, 1);
680}
681
682/* Return true if and only if a deferred request is queued. */
683static bool cache_defer_req(struct cache_req *req, struct cache_head *item)
684{
685 struct cache_deferred_req *dreq;
686
687 if (req->thread_wait) {
688 cache_wait_req(req, item);
689 if (!test_bit(CACHE_PENDING, &item->flags))
690 return false;
691 }
692 dreq = req->defer(req);
693 if (dreq == NULL)
694 return false;
695 setup_deferral(dreq, item, 1);
696 if (!test_bit(CACHE_PENDING, &item->flags))
697 /* Bit could have been cleared before we managed to
698 * set up the deferral, so need to revisit just in case
699 */
700 cache_revisit_request(item);
701
702 cache_limit_defers();
703 return true;
704}
705
706static void cache_revisit_request(struct cache_head *item)
707{
708 struct cache_deferred_req *dreq;
709 struct list_head pending;
710 struct hlist_node *tmp;
711 int hash = DFR_HASH(item);
712
713 INIT_LIST_HEAD(&pending);
714 spin_lock(&cache_defer_lock);
715
716 hlist_for_each_entry_safe(dreq, tmp, &cache_defer_hash[hash], hash)
717 if (dreq->item == item) {
718 __unhash_deferred_req(dreq);
719 list_add(&dreq->recent, &pending);
720 }
721
722 spin_unlock(&cache_defer_lock);
723
724 while (!list_empty(&pending)) {
725 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
726 list_del_init(&dreq->recent);
727 dreq->revisit(dreq, 0);
728 }
729}
730
731void cache_clean_deferred(void *owner)
732{
733 struct cache_deferred_req *dreq, *tmp;
734 struct list_head pending;
735
736
737 INIT_LIST_HEAD(&pending);
738 spin_lock(&cache_defer_lock);
739
740 list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) {
741 if (dreq->owner == owner) {
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, 1);
752 }
753}
754
755/*
756 * communicate with user-space
757 *
758 * We have a magic /proc file - /proc/net/rpc/<cachename>/channel.
759 * On read, you get a full request, or block.
760 * On write, an update request is processed.
761 * Poll works if anything to read, and always allows write.
762 *
763 * Implemented by linked list of requests. Each open file has
764 * a ->private that also exists in this list. New requests are added
765 * to the end and may wakeup and preceding readers.
766 * New readers are added to the head. If, on read, an item is found with
767 * CACHE_UPCALLING clear, we free it from the list.
768 *
769 */
770
771static DEFINE_SPINLOCK(queue_lock);
772static DEFINE_MUTEX(queue_io_mutex);
773
774struct cache_queue {
775 struct list_head list;
776 int reader; /* if 0, then request */
777};
778struct cache_request {
779 struct cache_queue q;
780 struct cache_head *item;
781 char * buf;
782 int len;
783 int readers;
784};
785struct cache_reader {
786 struct cache_queue q;
787 int offset; /* if non-0, we have a refcnt on next request */
788};
789
790static int cache_request(struct cache_detail *detail,
791 struct cache_request *crq)
792{
793 char *bp = crq->buf;
794 int len = PAGE_SIZE;
795
796 detail->cache_request(detail, crq->item, &bp, &len);
797 if (len < 0)
798 return -EAGAIN;
799 return PAGE_SIZE - len;
800}
801
802static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
803 loff_t *ppos, struct cache_detail *cd)
804{
805 struct cache_reader *rp = filp->private_data;
806 struct cache_request *rq;
807 struct inode *inode = file_inode(filp);
808 int err;
809
810 if (count == 0)
811 return 0;
812
813 inode_lock(inode); /* protect against multiple concurrent
814 * readers on this file */
815 again:
816 spin_lock(&queue_lock);
817 /* need to find next request */
818 while (rp->q.list.next != &cd->queue &&
819 list_entry(rp->q.list.next, struct cache_queue, list)
820 ->reader) {
821 struct list_head *next = rp->q.list.next;
822 list_move(&rp->q.list, next);
823 }
824 if (rp->q.list.next == &cd->queue) {
825 spin_unlock(&queue_lock);
826 inode_unlock(inode);
827 WARN_ON_ONCE(rp->offset);
828 return 0;
829 }
830 rq = container_of(rp->q.list.next, struct cache_request, q.list);
831 WARN_ON_ONCE(rq->q.reader);
832 if (rp->offset == 0)
833 rq->readers++;
834 spin_unlock(&queue_lock);
835
836 if (rq->len == 0) {
837 err = cache_request(cd, rq);
838 if (err < 0)
839 goto out;
840 rq->len = err;
841 }
842
843 if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
844 err = -EAGAIN;
845 spin_lock(&queue_lock);
846 list_move(&rp->q.list, &rq->q.list);
847 spin_unlock(&queue_lock);
848 } else {
849 if (rp->offset + count > rq->len)
850 count = rq->len - rp->offset;
851 err = -EFAULT;
852 if (copy_to_user(buf, rq->buf + rp->offset, count))
853 goto out;
854 rp->offset += count;
855 if (rp->offset >= rq->len) {
856 rp->offset = 0;
857 spin_lock(&queue_lock);
858 list_move(&rp->q.list, &rq->q.list);
859 spin_unlock(&queue_lock);
860 }
861 err = 0;
862 }
863 out:
864 if (rp->offset == 0) {
865 /* need to release rq */
866 spin_lock(&queue_lock);
867 rq->readers--;
868 if (rq->readers == 0 &&
869 !test_bit(CACHE_PENDING, &rq->item->flags)) {
870 list_del(&rq->q.list);
871 spin_unlock(&queue_lock);
872 cache_put(rq->item, cd);
873 kfree(rq->buf);
874 kfree(rq);
875 } else
876 spin_unlock(&queue_lock);
877 }
878 if (err == -EAGAIN)
879 goto again;
880 inode_unlock(inode);
881 return err ? err : count;
882}
883
884static ssize_t cache_do_downcall(char *kaddr, const char __user *buf,
885 size_t count, struct cache_detail *cd)
886{
887 ssize_t ret;
888
889 if (count == 0)
890 return -EINVAL;
891 if (copy_from_user(kaddr, buf, count))
892 return -EFAULT;
893 kaddr[count] = '\0';
894 ret = cd->cache_parse(cd, kaddr, count);
895 if (!ret)
896 ret = count;
897 return ret;
898}
899
900static ssize_t cache_slow_downcall(const char __user *buf,
901 size_t count, struct cache_detail *cd)
902{
903 static char write_buf[8192]; /* protected by queue_io_mutex */
904 ssize_t ret = -EINVAL;
905
906 if (count >= sizeof(write_buf))
907 goto out;
908 mutex_lock(&queue_io_mutex);
909 ret = cache_do_downcall(write_buf, buf, count, cd);
910 mutex_unlock(&queue_io_mutex);
911out:
912 return ret;
913}
914
915static ssize_t cache_downcall(struct address_space *mapping,
916 const char __user *buf,
917 size_t count, struct cache_detail *cd)
918{
919 struct page *page;
920 char *kaddr;
921 ssize_t ret = -ENOMEM;
922
923 if (count >= PAGE_SIZE)
924 goto out_slow;
925
926 page = find_or_create_page(mapping, 0, GFP_KERNEL);
927 if (!page)
928 goto out_slow;
929
930 kaddr = kmap(page);
931 ret = cache_do_downcall(kaddr, buf, count, cd);
932 kunmap(page);
933 unlock_page(page);
934 put_page(page);
935 return ret;
936out_slow:
937 return cache_slow_downcall(buf, count, cd);
938}
939
940static ssize_t cache_write(struct file *filp, const char __user *buf,
941 size_t count, loff_t *ppos,
942 struct cache_detail *cd)
943{
944 struct address_space *mapping = filp->f_mapping;
945 struct inode *inode = file_inode(filp);
946 ssize_t ret = -EINVAL;
947
948 if (!cd->cache_parse)
949 goto out;
950
951 inode_lock(inode);
952 ret = cache_downcall(mapping, buf, count, cd);
953 inode_unlock(inode);
954out:
955 return ret;
956}
957
958static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
959
960static __poll_t cache_poll(struct file *filp, poll_table *wait,
961 struct cache_detail *cd)
962{
963 __poll_t mask;
964 struct cache_reader *rp = filp->private_data;
965 struct cache_queue *cq;
966
967 poll_wait(filp, &queue_wait, wait);
968
969 /* alway allow write */
970 mask = EPOLLOUT | EPOLLWRNORM;
971
972 if (!rp)
973 return mask;
974
975 spin_lock(&queue_lock);
976
977 for (cq= &rp->q; &cq->list != &cd->queue;
978 cq = list_entry(cq->list.next, struct cache_queue, list))
979 if (!cq->reader) {
980 mask |= EPOLLIN | EPOLLRDNORM;
981 break;
982 }
983 spin_unlock(&queue_lock);
984 return mask;
985}
986
987static int cache_ioctl(struct inode *ino, struct file *filp,
988 unsigned int cmd, unsigned long arg,
989 struct cache_detail *cd)
990{
991 int len = 0;
992 struct cache_reader *rp = filp->private_data;
993 struct cache_queue *cq;
994
995 if (cmd != FIONREAD || !rp)
996 return -EINVAL;
997
998 spin_lock(&queue_lock);
999
1000 /* only find the length remaining in current request,
1001 * or the length of the next request
1002 */
1003 for (cq= &rp->q; &cq->list != &cd->queue;
1004 cq = list_entry(cq->list.next, struct cache_queue, list))
1005 if (!cq->reader) {
1006 struct cache_request *cr =
1007 container_of(cq, struct cache_request, q);
1008 len = cr->len - rp->offset;
1009 break;
1010 }
1011 spin_unlock(&queue_lock);
1012
1013 return put_user(len, (int __user *)arg);
1014}
1015
1016static int cache_open(struct inode *inode, struct file *filp,
1017 struct cache_detail *cd)
1018{
1019 struct cache_reader *rp = NULL;
1020
1021 if (!cd || !try_module_get(cd->owner))
1022 return -EACCES;
1023 nonseekable_open(inode, filp);
1024 if (filp->f_mode & FMODE_READ) {
1025 rp = kmalloc(sizeof(*rp), GFP_KERNEL);
1026 if (!rp) {
1027 module_put(cd->owner);
1028 return -ENOMEM;
1029 }
1030 rp->offset = 0;
1031 rp->q.reader = 1;
1032
1033 spin_lock(&queue_lock);
1034 list_add(&rp->q.list, &cd->queue);
1035 spin_unlock(&queue_lock);
1036 }
1037 if (filp->f_mode & FMODE_WRITE)
1038 atomic_inc(&cd->writers);
1039 filp->private_data = rp;
1040 return 0;
1041}
1042
1043static int cache_release(struct inode *inode, struct file *filp,
1044 struct cache_detail *cd)
1045{
1046 struct cache_reader *rp = filp->private_data;
1047
1048 if (rp) {
1049 spin_lock(&queue_lock);
1050 if (rp->offset) {
1051 struct cache_queue *cq;
1052 for (cq= &rp->q; &cq->list != &cd->queue;
1053 cq = list_entry(cq->list.next, struct cache_queue, list))
1054 if (!cq->reader) {
1055 container_of(cq, struct cache_request, q)
1056 ->readers--;
1057 break;
1058 }
1059 rp->offset = 0;
1060 }
1061 list_del(&rp->q.list);
1062 spin_unlock(&queue_lock);
1063
1064 filp->private_data = NULL;
1065 kfree(rp);
1066
1067 }
1068 if (filp->f_mode & FMODE_WRITE) {
1069 atomic_dec(&cd->writers);
1070 cd->last_close = seconds_since_boot();
1071 }
1072 module_put(cd->owner);
1073 return 0;
1074}
1075
1076
1077
1078static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch)
1079{
1080 struct cache_queue *cq, *tmp;
1081 struct cache_request *cr;
1082 struct list_head dequeued;
1083
1084 INIT_LIST_HEAD(&dequeued);
1085 spin_lock(&queue_lock);
1086 list_for_each_entry_safe(cq, tmp, &detail->queue, list)
1087 if (!cq->reader) {
1088 cr = container_of(cq, struct cache_request, q);
1089 if (cr->item != ch)
1090 continue;
1091 if (test_bit(CACHE_PENDING, &ch->flags))
1092 /* Lost a race and it is pending again */
1093 break;
1094 if (cr->readers != 0)
1095 continue;
1096 list_move(&cr->q.list, &dequeued);
1097 }
1098 spin_unlock(&queue_lock);
1099 while (!list_empty(&dequeued)) {
1100 cr = list_entry(dequeued.next, struct cache_request, q.list);
1101 list_del(&cr->q.list);
1102 cache_put(cr->item, detail);
1103 kfree(cr->buf);
1104 kfree(cr);
1105 }
1106}
1107
1108/*
1109 * Support routines for text-based upcalls.
1110 * Fields are separated by spaces.
1111 * Fields are either mangled to quote space tab newline slosh with slosh
1112 * or a hexified with a leading \x
1113 * Record is terminated with newline.
1114 *
1115 */
1116
1117void qword_add(char **bpp, int *lp, char *str)
1118{
1119 char *bp = *bpp;
1120 int len = *lp;
1121 int ret;
1122
1123 if (len < 0) return;
1124
1125 ret = string_escape_str(str, bp, len, ESCAPE_OCTAL, "\\ \n\t");
1126 if (ret >= len) {
1127 bp += len;
1128 len = -1;
1129 } else {
1130 bp += ret;
1131 len -= ret;
1132 *bp++ = ' ';
1133 len--;
1134 }
1135 *bpp = bp;
1136 *lp = len;
1137}
1138EXPORT_SYMBOL_GPL(qword_add);
1139
1140void qword_addhex(char **bpp, int *lp, char *buf, int blen)
1141{
1142 char *bp = *bpp;
1143 int len = *lp;
1144
1145 if (len < 0) return;
1146
1147 if (len > 2) {
1148 *bp++ = '\\';
1149 *bp++ = 'x';
1150 len -= 2;
1151 while (blen && len >= 2) {
1152 bp = hex_byte_pack(bp, *buf++);
1153 len -= 2;
1154 blen--;
1155 }
1156 }
1157 if (blen || len<1) len = -1;
1158 else {
1159 *bp++ = ' ';
1160 len--;
1161 }
1162 *bpp = bp;
1163 *lp = len;
1164}
1165EXPORT_SYMBOL_GPL(qword_addhex);
1166
1167static void warn_no_listener(struct cache_detail *detail)
1168{
1169 if (detail->last_warn != detail->last_close) {
1170 detail->last_warn = detail->last_close;
1171 if (detail->warn_no_listener)
1172 detail->warn_no_listener(detail, detail->last_close != 0);
1173 }
1174}
1175
1176static bool cache_listeners_exist(struct cache_detail *detail)
1177{
1178 if (atomic_read(&detail->writers))
1179 return true;
1180 if (detail->last_close == 0)
1181 /* This cache was never opened */
1182 return false;
1183 if (detail->last_close < seconds_since_boot() - 30)
1184 /*
1185 * We allow for the possibility that someone might
1186 * restart a userspace daemon without restarting the
1187 * server; but after 30 seconds, we give up.
1188 */
1189 return false;
1190 return true;
1191}
1192
1193/*
1194 * register an upcall request to user-space and queue it up for read() by the
1195 * upcall daemon.
1196 *
1197 * Each request is at most one page long.
1198 */
1199int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
1200{
1201
1202 char *buf;
1203 struct cache_request *crq;
1204 int ret = 0;
1205
1206 if (!detail->cache_request)
1207 return -EINVAL;
1208
1209 if (!cache_listeners_exist(detail)) {
1210 warn_no_listener(detail);
1211 return -EINVAL;
1212 }
1213 if (test_bit(CACHE_CLEANED, &h->flags))
1214 /* Too late to make an upcall */
1215 return -EAGAIN;
1216
1217 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1218 if (!buf)
1219 return -EAGAIN;
1220
1221 crq = kmalloc(sizeof (*crq), GFP_KERNEL);
1222 if (!crq) {
1223 kfree(buf);
1224 return -EAGAIN;
1225 }
1226
1227 crq->q.reader = 0;
1228 crq->buf = buf;
1229 crq->len = 0;
1230 crq->readers = 0;
1231 spin_lock(&queue_lock);
1232 if (test_bit(CACHE_PENDING, &h->flags)) {
1233 crq->item = cache_get(h);
1234 list_add_tail(&crq->q.list, &detail->queue);
1235 } else
1236 /* Lost a race, no longer PENDING, so don't enqueue */
1237 ret = -EAGAIN;
1238 spin_unlock(&queue_lock);
1239 wake_up(&queue_wait);
1240 if (ret == -EAGAIN) {
1241 kfree(buf);
1242 kfree(crq);
1243 }
1244 return ret;
1245}
1246EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall);
1247
1248/*
1249 * parse a message from user-space and pass it
1250 * to an appropriate cache
1251 * Messages are, like requests, separated into fields by
1252 * spaces and dequotes as \xHEXSTRING or embedded \nnn octal
1253 *
1254 * Message is
1255 * reply cachename expiry key ... content....
1256 *
1257 * key and content are both parsed by cache
1258 */
1259
1260int qword_get(char **bpp, char *dest, int bufsize)
1261{
1262 /* return bytes copied, or -1 on error */
1263 char *bp = *bpp;
1264 int len = 0;
1265
1266 while (*bp == ' ') bp++;
1267
1268 if (bp[0] == '\\' && bp[1] == 'x') {
1269 /* HEX STRING */
1270 bp += 2;
1271 while (len < bufsize - 1) {
1272 int h, l;
1273
1274 h = hex_to_bin(bp[0]);
1275 if (h < 0)
1276 break;
1277
1278 l = hex_to_bin(bp[1]);
1279 if (l < 0)
1280 break;
1281
1282 *dest++ = (h << 4) | l;
1283 bp += 2;
1284 len++;
1285 }
1286 } else {
1287 /* text with \nnn octal quoting */
1288 while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) {
1289 if (*bp == '\\' &&
1290 isodigit(bp[1]) && (bp[1] <= '3') &&
1291 isodigit(bp[2]) &&
1292 isodigit(bp[3])) {
1293 int byte = (*++bp -'0');
1294 bp++;
1295 byte = (byte << 3) | (*bp++ - '0');
1296 byte = (byte << 3) | (*bp++ - '0');
1297 *dest++ = byte;
1298 len++;
1299 } else {
1300 *dest++ = *bp++;
1301 len++;
1302 }
1303 }
1304 }
1305
1306 if (*bp != ' ' && *bp != '\n' && *bp != '\0')
1307 return -1;
1308 while (*bp == ' ') bp++;
1309 *bpp = bp;
1310 *dest = '\0';
1311 return len;
1312}
1313EXPORT_SYMBOL_GPL(qword_get);
1314
1315
1316/*
1317 * support /proc/net/rpc/$CACHENAME/content
1318 * as a seqfile.
1319 * We call ->cache_show passing NULL for the item to
1320 * get a header, then pass each real item in the cache
1321 */
1322
1323static void *__cache_seq_start(struct seq_file *m, loff_t *pos)
1324{
1325 loff_t n = *pos;
1326 unsigned int hash, entry;
1327 struct cache_head *ch;
1328 struct cache_detail *cd = m->private;
1329
1330 if (!n--)
1331 return SEQ_START_TOKEN;
1332 hash = n >> 32;
1333 entry = n & ((1LL<<32) - 1);
1334
1335 hlist_for_each_entry_rcu(ch, &cd->hash_table[hash], cache_list)
1336 if (!entry--)
1337 return ch;
1338 n &= ~((1LL<<32) - 1);
1339 do {
1340 hash++;
1341 n += 1LL<<32;
1342 } while(hash < cd->hash_size &&
1343 hlist_empty(&cd->hash_table[hash]));
1344 if (hash >= cd->hash_size)
1345 return NULL;
1346 *pos = n+1;
1347 return hlist_entry_safe(rcu_dereference_raw(
1348 hlist_first_rcu(&cd->hash_table[hash])),
1349 struct cache_head, cache_list);
1350}
1351
1352static void *cache_seq_next(struct seq_file *m, void *p, loff_t *pos)
1353{
1354 struct cache_head *ch = p;
1355 int hash = (*pos >> 32);
1356 struct cache_detail *cd = m->private;
1357
1358 if (p == SEQ_START_TOKEN)
1359 hash = 0;
1360 else if (ch->cache_list.next == NULL) {
1361 hash++;
1362 *pos += 1LL<<32;
1363 } else {
1364 ++*pos;
1365 return hlist_entry_safe(rcu_dereference_raw(
1366 hlist_next_rcu(&ch->cache_list)),
1367 struct cache_head, cache_list);
1368 }
1369 *pos &= ~((1LL<<32) - 1);
1370 while (hash < cd->hash_size &&
1371 hlist_empty(&cd->hash_table[hash])) {
1372 hash++;
1373 *pos += 1LL<<32;
1374 }
1375 if (hash >= cd->hash_size)
1376 return NULL;
1377 ++*pos;
1378 return hlist_entry_safe(rcu_dereference_raw(
1379 hlist_first_rcu(&cd->hash_table[hash])),
1380 struct cache_head, cache_list);
1381}
1382
1383void *cache_seq_start_rcu(struct seq_file *m, loff_t *pos)
1384 __acquires(RCU)
1385{
1386 rcu_read_lock();
1387 return __cache_seq_start(m, pos);
1388}
1389EXPORT_SYMBOL_GPL(cache_seq_start_rcu);
1390
1391void *cache_seq_next_rcu(struct seq_file *file, void *p, loff_t *pos)
1392{
1393 return cache_seq_next(file, p, pos);
1394}
1395EXPORT_SYMBOL_GPL(cache_seq_next_rcu);
1396
1397void cache_seq_stop_rcu(struct seq_file *m, void *p)
1398 __releases(RCU)
1399{
1400 rcu_read_unlock();
1401}
1402EXPORT_SYMBOL_GPL(cache_seq_stop_rcu);
1403
1404static int c_show(struct seq_file *m, void *p)
1405{
1406 struct cache_head *cp = p;
1407 struct cache_detail *cd = m->private;
1408
1409 if (p == SEQ_START_TOKEN)
1410 return cd->cache_show(m, cd, NULL);
1411
1412 ifdebug(CACHE)
1413 seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n",
1414 convert_to_wallclock(cp->expiry_time),
1415 kref_read(&cp->ref), cp->flags);
1416 cache_get(cp);
1417 if (cache_check(cd, cp, NULL))
1418 /* cache_check does a cache_put on failure */
1419 seq_printf(m, "# ");
1420 else {
1421 if (cache_is_expired(cd, cp))
1422 seq_printf(m, "# ");
1423 cache_put(cp, cd);
1424 }
1425
1426 return cd->cache_show(m, cd, cp);
1427}
1428
1429static const struct seq_operations cache_content_op = {
1430 .start = cache_seq_start_rcu,
1431 .next = cache_seq_next_rcu,
1432 .stop = cache_seq_stop_rcu,
1433 .show = c_show,
1434};
1435
1436static int content_open(struct inode *inode, struct file *file,
1437 struct cache_detail *cd)
1438{
1439 struct seq_file *seq;
1440 int err;
1441
1442 if (!cd || !try_module_get(cd->owner))
1443 return -EACCES;
1444
1445 err = seq_open(file, &cache_content_op);
1446 if (err) {
1447 module_put(cd->owner);
1448 return err;
1449 }
1450
1451 seq = file->private_data;
1452 seq->private = cd;
1453 return 0;
1454}
1455
1456static int content_release(struct inode *inode, struct file *file,
1457 struct cache_detail *cd)
1458{
1459 int ret = seq_release(inode, file);
1460 module_put(cd->owner);
1461 return ret;
1462}
1463
1464static int open_flush(struct inode *inode, struct file *file,
1465 struct cache_detail *cd)
1466{
1467 if (!cd || !try_module_get(cd->owner))
1468 return -EACCES;
1469 return nonseekable_open(inode, file);
1470}
1471
1472static int release_flush(struct inode *inode, struct file *file,
1473 struct cache_detail *cd)
1474{
1475 module_put(cd->owner);
1476 return 0;
1477}
1478
1479static ssize_t read_flush(struct file *file, char __user *buf,
1480 size_t count, loff_t *ppos,
1481 struct cache_detail *cd)
1482{
1483 char tbuf[22];
1484 size_t len;
1485
1486 len = snprintf(tbuf, sizeof(tbuf), "%lu\n",
1487 convert_to_wallclock(cd->flush_time));
1488 return simple_read_from_buffer(buf, count, ppos, tbuf, len);
1489}
1490
1491static ssize_t write_flush(struct file *file, const char __user *buf,
1492 size_t count, loff_t *ppos,
1493 struct cache_detail *cd)
1494{
1495 char tbuf[20];
1496 char *ep;
1497 time_t now;
1498
1499 if (*ppos || count > sizeof(tbuf)-1)
1500 return -EINVAL;
1501 if (copy_from_user(tbuf, buf, count))
1502 return -EFAULT;
1503 tbuf[count] = 0;
1504 simple_strtoul(tbuf, &ep, 0);
1505 if (*ep && *ep != '\n')
1506 return -EINVAL;
1507 /* Note that while we check that 'buf' holds a valid number,
1508 * we always ignore the value and just flush everything.
1509 * Making use of the number leads to races.
1510 */
1511
1512 now = seconds_since_boot();
1513 /* Always flush everything, so behave like cache_purge()
1514 * Do this by advancing flush_time to the current time,
1515 * or by one second if it has already reached the current time.
1516 * Newly added cache entries will always have ->last_refresh greater
1517 * that ->flush_time, so they don't get flushed prematurely.
1518 */
1519
1520 if (cd->flush_time >= now)
1521 now = cd->flush_time + 1;
1522
1523 cd->flush_time = now;
1524 cd->nextcheck = now;
1525 cache_flush();
1526
1527 if (cd->flush)
1528 cd->flush();
1529
1530 *ppos += count;
1531 return count;
1532}
1533
1534static ssize_t cache_read_procfs(struct file *filp, char __user *buf,
1535 size_t count, loff_t *ppos)
1536{
1537 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1538
1539 return cache_read(filp, buf, count, ppos, cd);
1540}
1541
1542static ssize_t cache_write_procfs(struct file *filp, const char __user *buf,
1543 size_t count, loff_t *ppos)
1544{
1545 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1546
1547 return cache_write(filp, buf, count, ppos, cd);
1548}
1549
1550static __poll_t cache_poll_procfs(struct file *filp, poll_table *wait)
1551{
1552 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1553
1554 return cache_poll(filp, wait, cd);
1555}
1556
1557static long cache_ioctl_procfs(struct file *filp,
1558 unsigned int cmd, unsigned long arg)
1559{
1560 struct inode *inode = file_inode(filp);
1561 struct cache_detail *cd = PDE_DATA(inode);
1562
1563 return cache_ioctl(inode, filp, cmd, arg, cd);
1564}
1565
1566static int cache_open_procfs(struct inode *inode, struct file *filp)
1567{
1568 struct cache_detail *cd = PDE_DATA(inode);
1569
1570 return cache_open(inode, filp, cd);
1571}
1572
1573static int cache_release_procfs(struct inode *inode, struct file *filp)
1574{
1575 struct cache_detail *cd = PDE_DATA(inode);
1576
1577 return cache_release(inode, filp, cd);
1578}
1579
1580static const struct file_operations cache_file_operations_procfs = {
1581 .owner = THIS_MODULE,
1582 .llseek = no_llseek,
1583 .read = cache_read_procfs,
1584 .write = cache_write_procfs,
1585 .poll = cache_poll_procfs,
1586 .unlocked_ioctl = cache_ioctl_procfs, /* for FIONREAD */
1587 .open = cache_open_procfs,
1588 .release = cache_release_procfs,
1589};
1590
1591static int content_open_procfs(struct inode *inode, struct file *filp)
1592{
1593 struct cache_detail *cd = PDE_DATA(inode);
1594
1595 return content_open(inode, filp, cd);
1596}
1597
1598static int content_release_procfs(struct inode *inode, struct file *filp)
1599{
1600 struct cache_detail *cd = PDE_DATA(inode);
1601
1602 return content_release(inode, filp, cd);
1603}
1604
1605static const struct file_operations content_file_operations_procfs = {
1606 .open = content_open_procfs,
1607 .read = seq_read,
1608 .llseek = seq_lseek,
1609 .release = content_release_procfs,
1610};
1611
1612static int open_flush_procfs(struct inode *inode, struct file *filp)
1613{
1614 struct cache_detail *cd = PDE_DATA(inode);
1615
1616 return open_flush(inode, filp, cd);
1617}
1618
1619static int release_flush_procfs(struct inode *inode, struct file *filp)
1620{
1621 struct cache_detail *cd = PDE_DATA(inode);
1622
1623 return release_flush(inode, filp, cd);
1624}
1625
1626static ssize_t read_flush_procfs(struct file *filp, char __user *buf,
1627 size_t count, loff_t *ppos)
1628{
1629 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1630
1631 return read_flush(filp, buf, count, ppos, cd);
1632}
1633
1634static ssize_t write_flush_procfs(struct file *filp,
1635 const char __user *buf,
1636 size_t count, loff_t *ppos)
1637{
1638 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1639
1640 return write_flush(filp, buf, count, ppos, cd);
1641}
1642
1643static const struct file_operations cache_flush_operations_procfs = {
1644 .open = open_flush_procfs,
1645 .read = read_flush_procfs,
1646 .write = write_flush_procfs,
1647 .release = release_flush_procfs,
1648 .llseek = no_llseek,
1649};
1650
1651static void remove_cache_proc_entries(struct cache_detail *cd)
1652{
1653 if (cd->procfs) {
1654 proc_remove(cd->procfs);
1655 cd->procfs = NULL;
1656 }
1657}
1658
1659#ifdef CONFIG_PROC_FS
1660static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1661{
1662 struct proc_dir_entry *p;
1663 struct sunrpc_net *sn;
1664
1665 sn = net_generic(net, sunrpc_net_id);
1666 cd->procfs = proc_mkdir(cd->name, sn->proc_net_rpc);
1667 if (cd->procfs == NULL)
1668 goto out_nomem;
1669
1670 p = proc_create_data("flush", S_IFREG | 0600,
1671 cd->procfs, &cache_flush_operations_procfs, cd);
1672 if (p == NULL)
1673 goto out_nomem;
1674
1675 if (cd->cache_request || cd->cache_parse) {
1676 p = proc_create_data("channel", S_IFREG | 0600, cd->procfs,
1677 &cache_file_operations_procfs, cd);
1678 if (p == NULL)
1679 goto out_nomem;
1680 }
1681 if (cd->cache_show) {
1682 p = proc_create_data("content", S_IFREG | 0400, cd->procfs,
1683 &content_file_operations_procfs, cd);
1684 if (p == NULL)
1685 goto out_nomem;
1686 }
1687 return 0;
1688out_nomem:
1689 remove_cache_proc_entries(cd);
1690 return -ENOMEM;
1691}
1692#else /* CONFIG_PROC_FS */
1693static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1694{
1695 return 0;
1696}
1697#endif
1698
1699void __init cache_initialize(void)
1700{
1701 INIT_DEFERRABLE_WORK(&cache_cleaner, do_cache_clean);
1702}
1703
1704int cache_register_net(struct cache_detail *cd, struct net *net)
1705{
1706 int ret;
1707
1708 sunrpc_init_cache_detail(cd);
1709 ret = create_cache_proc_entries(cd, net);
1710 if (ret)
1711 sunrpc_destroy_cache_detail(cd);
1712 return ret;
1713}
1714EXPORT_SYMBOL_GPL(cache_register_net);
1715
1716void cache_unregister_net(struct cache_detail *cd, struct net *net)
1717{
1718 remove_cache_proc_entries(cd);
1719 sunrpc_destroy_cache_detail(cd);
1720}
1721EXPORT_SYMBOL_GPL(cache_unregister_net);
1722
1723struct cache_detail *cache_create_net(const struct cache_detail *tmpl, struct net *net)
1724{
1725 struct cache_detail *cd;
1726 int i;
1727
1728 cd = kmemdup(tmpl, sizeof(struct cache_detail), GFP_KERNEL);
1729 if (cd == NULL)
1730 return ERR_PTR(-ENOMEM);
1731
1732 cd->hash_table = kcalloc(cd->hash_size, sizeof(struct hlist_head),
1733 GFP_KERNEL);
1734 if (cd->hash_table == NULL) {
1735 kfree(cd);
1736 return ERR_PTR(-ENOMEM);
1737 }
1738
1739 for (i = 0; i < cd->hash_size; i++)
1740 INIT_HLIST_HEAD(&cd->hash_table[i]);
1741 cd->net = net;
1742 return cd;
1743}
1744EXPORT_SYMBOL_GPL(cache_create_net);
1745
1746void cache_destroy_net(struct cache_detail *cd, struct net *net)
1747{
1748 kfree(cd->hash_table);
1749 kfree(cd);
1750}
1751EXPORT_SYMBOL_GPL(cache_destroy_net);
1752
1753static ssize_t cache_read_pipefs(struct file *filp, char __user *buf,
1754 size_t count, loff_t *ppos)
1755{
1756 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1757
1758 return cache_read(filp, buf, count, ppos, cd);
1759}
1760
1761static ssize_t cache_write_pipefs(struct file *filp, const char __user *buf,
1762 size_t count, loff_t *ppos)
1763{
1764 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1765
1766 return cache_write(filp, buf, count, ppos, cd);
1767}
1768
1769static __poll_t cache_poll_pipefs(struct file *filp, poll_table *wait)
1770{
1771 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1772
1773 return cache_poll(filp, wait, cd);
1774}
1775
1776static long cache_ioctl_pipefs(struct file *filp,
1777 unsigned int cmd, unsigned long arg)
1778{
1779 struct inode *inode = file_inode(filp);
1780 struct cache_detail *cd = RPC_I(inode)->private;
1781
1782 return cache_ioctl(inode, filp, cmd, arg, cd);
1783}
1784
1785static int cache_open_pipefs(struct inode *inode, struct file *filp)
1786{
1787 struct cache_detail *cd = RPC_I(inode)->private;
1788
1789 return cache_open(inode, filp, cd);
1790}
1791
1792static int cache_release_pipefs(struct inode *inode, struct file *filp)
1793{
1794 struct cache_detail *cd = RPC_I(inode)->private;
1795
1796 return cache_release(inode, filp, cd);
1797}
1798
1799const struct file_operations cache_file_operations_pipefs = {
1800 .owner = THIS_MODULE,
1801 .llseek = no_llseek,
1802 .read = cache_read_pipefs,
1803 .write = cache_write_pipefs,
1804 .poll = cache_poll_pipefs,
1805 .unlocked_ioctl = cache_ioctl_pipefs, /* for FIONREAD */
1806 .open = cache_open_pipefs,
1807 .release = cache_release_pipefs,
1808};
1809
1810static int content_open_pipefs(struct inode *inode, struct file *filp)
1811{
1812 struct cache_detail *cd = RPC_I(inode)->private;
1813
1814 return content_open(inode, filp, cd);
1815}
1816
1817static int content_release_pipefs(struct inode *inode, struct file *filp)
1818{
1819 struct cache_detail *cd = RPC_I(inode)->private;
1820
1821 return content_release(inode, filp, cd);
1822}
1823
1824const struct file_operations content_file_operations_pipefs = {
1825 .open = content_open_pipefs,
1826 .read = seq_read,
1827 .llseek = seq_lseek,
1828 .release = content_release_pipefs,
1829};
1830
1831static int open_flush_pipefs(struct inode *inode, struct file *filp)
1832{
1833 struct cache_detail *cd = RPC_I(inode)->private;
1834
1835 return open_flush(inode, filp, cd);
1836}
1837
1838static int release_flush_pipefs(struct inode *inode, struct file *filp)
1839{
1840 struct cache_detail *cd = RPC_I(inode)->private;
1841
1842 return release_flush(inode, filp, cd);
1843}
1844
1845static ssize_t read_flush_pipefs(struct file *filp, char __user *buf,
1846 size_t count, loff_t *ppos)
1847{
1848 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1849
1850 return read_flush(filp, buf, count, ppos, cd);
1851}
1852
1853static ssize_t write_flush_pipefs(struct file *filp,
1854 const char __user *buf,
1855 size_t count, loff_t *ppos)
1856{
1857 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1858
1859 return write_flush(filp, buf, count, ppos, cd);
1860}
1861
1862const struct file_operations cache_flush_operations_pipefs = {
1863 .open = open_flush_pipefs,
1864 .read = read_flush_pipefs,
1865 .write = write_flush_pipefs,
1866 .release = release_flush_pipefs,
1867 .llseek = no_llseek,
1868};
1869
1870int sunrpc_cache_register_pipefs(struct dentry *parent,
1871 const char *name, umode_t umode,
1872 struct cache_detail *cd)
1873{
1874 struct dentry *dir = rpc_create_cache_dir(parent, name, umode, cd);
1875 if (IS_ERR(dir))
1876 return PTR_ERR(dir);
1877 cd->pipefs = dir;
1878 return 0;
1879}
1880EXPORT_SYMBOL_GPL(sunrpc_cache_register_pipefs);
1881
1882void sunrpc_cache_unregister_pipefs(struct cache_detail *cd)
1883{
1884 if (cd->pipefs) {
1885 rpc_remove_cache_dir(cd->pipefs);
1886 cd->pipefs = NULL;
1887 }
1888}
1889EXPORT_SYMBOL_GPL(sunrpc_cache_unregister_pipefs);
1890
1891void sunrpc_cache_unhash(struct cache_detail *cd, struct cache_head *h)
1892{
1893 spin_lock(&cd->hash_lock);
1894 if (!hlist_unhashed(&h->cache_list)){
1895 hlist_del_init_rcu(&h->cache_list);
1896 cd->entries--;
1897 spin_unlock(&cd->hash_lock);
1898 cache_put(h, cd);
1899 } else
1900 spin_unlock(&cd->hash_lock);
1901}
1902EXPORT_SYMBOL_GPL(sunrpc_cache_unhash);
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(¤t_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(¤t_detail->hash_lock);
469
470 /* Ok, now to clean this strand */
471
472 head = ¤t_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(¤t_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);