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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#include "netns.h"
37
38#define RPCDBG_FACILITY RPCDBG_CACHE
39
40static bool cache_defer_req(struct cache_req *req, struct cache_head *item);
41static void cache_revisit_request(struct cache_head *item);
42
43static void cache_init(struct cache_head *h, struct cache_detail *detail)
44{
45 time64_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 void cache_fresh_unlocked(struct cache_head *head,
57 struct cache_detail *detail);
58
59static struct cache_head *sunrpc_cache_find_rcu(struct cache_detail *detail,
60 struct cache_head *key,
61 int hash)
62{
63 struct hlist_head *head = &detail->hash_table[hash];
64 struct cache_head *tmp;
65
66 rcu_read_lock();
67 hlist_for_each_entry_rcu(tmp, head, cache_list) {
68 if (!detail->match(tmp, key))
69 continue;
70 if (test_bit(CACHE_VALID, &tmp->flags) &&
71 cache_is_expired(detail, tmp))
72 continue;
73 tmp = cache_get_rcu(tmp);
74 rcu_read_unlock();
75 return tmp;
76 }
77 rcu_read_unlock();
78 return NULL;
79}
80
81static void sunrpc_begin_cache_remove_entry(struct cache_head *ch,
82 struct cache_detail *cd)
83{
84 /* Must be called under cd->hash_lock */
85 hlist_del_init_rcu(&ch->cache_list);
86 set_bit(CACHE_CLEANED, &ch->flags);
87 cd->entries --;
88}
89
90static void sunrpc_end_cache_remove_entry(struct cache_head *ch,
91 struct cache_detail *cd)
92{
93 cache_fresh_unlocked(ch, cd);
94 cache_put(ch, cd);
95}
96
97static struct cache_head *sunrpc_cache_add_entry(struct cache_detail *detail,
98 struct cache_head *key,
99 int hash)
100{
101 struct cache_head *new, *tmp, *freeme = NULL;
102 struct hlist_head *head = &detail->hash_table[hash];
103
104 new = detail->alloc();
105 if (!new)
106 return NULL;
107 /* must fully initialise 'new', else
108 * we might get lose if we need to
109 * cache_put it soon.
110 */
111 cache_init(new, detail);
112 detail->init(new, key);
113
114 spin_lock(&detail->hash_lock);
115
116 /* check if entry appeared while we slept */
117 hlist_for_each_entry_rcu(tmp, head, cache_list,
118 lockdep_is_held(&detail->hash_lock)) {
119 if (!detail->match(tmp, key))
120 continue;
121 if (test_bit(CACHE_VALID, &tmp->flags) &&
122 cache_is_expired(detail, tmp)) {
123 sunrpc_begin_cache_remove_entry(tmp, detail);
124 trace_cache_entry_expired(detail, tmp);
125 freeme = tmp;
126 break;
127 }
128 cache_get(tmp);
129 spin_unlock(&detail->hash_lock);
130 cache_put(new, detail);
131 return tmp;
132 }
133
134 hlist_add_head_rcu(&new->cache_list, head);
135 detail->entries++;
136 cache_get(new);
137 spin_unlock(&detail->hash_lock);
138
139 if (freeme)
140 sunrpc_end_cache_remove_entry(freeme, detail);
141 return new;
142}
143
144struct cache_head *sunrpc_cache_lookup_rcu(struct cache_detail *detail,
145 struct cache_head *key, int hash)
146{
147 struct cache_head *ret;
148
149 ret = sunrpc_cache_find_rcu(detail, key, hash);
150 if (ret)
151 return ret;
152 /* Didn't find anything, insert an empty entry */
153 return sunrpc_cache_add_entry(detail, key, hash);
154}
155EXPORT_SYMBOL_GPL(sunrpc_cache_lookup_rcu);
156
157static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch);
158
159static void cache_fresh_locked(struct cache_head *head, time64_t expiry,
160 struct cache_detail *detail)
161{
162 time64_t now = seconds_since_boot();
163 if (now <= detail->flush_time)
164 /* ensure it isn't immediately treated as expired */
165 now = detail->flush_time + 1;
166 head->expiry_time = expiry;
167 head->last_refresh = now;
168 smp_wmb(); /* paired with smp_rmb() in cache_is_valid() */
169 set_bit(CACHE_VALID, &head->flags);
170}
171
172static void cache_fresh_unlocked(struct cache_head *head,
173 struct cache_detail *detail)
174{
175 if (test_and_clear_bit(CACHE_PENDING, &head->flags)) {
176 cache_revisit_request(head);
177 cache_dequeue(detail, head);
178 }
179}
180
181static void cache_make_negative(struct cache_detail *detail,
182 struct cache_head *h)
183{
184 set_bit(CACHE_NEGATIVE, &h->flags);
185 trace_cache_entry_make_negative(detail, h);
186}
187
188static void cache_entry_update(struct cache_detail *detail,
189 struct cache_head *h,
190 struct cache_head *new)
191{
192 if (!test_bit(CACHE_NEGATIVE, &new->flags)) {
193 detail->update(h, new);
194 trace_cache_entry_update(detail, h);
195 } else {
196 cache_make_negative(detail, h);
197 }
198}
199
200struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
201 struct cache_head *new, struct cache_head *old, int hash)
202{
203 /* The 'old' entry is to be replaced by 'new'.
204 * If 'old' is not VALID, we update it directly,
205 * otherwise we need to replace it
206 */
207 struct cache_head *tmp;
208
209 if (!test_bit(CACHE_VALID, &old->flags)) {
210 spin_lock(&detail->hash_lock);
211 if (!test_bit(CACHE_VALID, &old->flags)) {
212 cache_entry_update(detail, old, new);
213 cache_fresh_locked(old, new->expiry_time, detail);
214 spin_unlock(&detail->hash_lock);
215 cache_fresh_unlocked(old, detail);
216 return old;
217 }
218 spin_unlock(&detail->hash_lock);
219 }
220 /* We need to insert a new entry */
221 tmp = detail->alloc();
222 if (!tmp) {
223 cache_put(old, detail);
224 return NULL;
225 }
226 cache_init(tmp, detail);
227 detail->init(tmp, old);
228
229 spin_lock(&detail->hash_lock);
230 cache_entry_update(detail, tmp, new);
231 hlist_add_head(&tmp->cache_list, &detail->hash_table[hash]);
232 detail->entries++;
233 cache_get(tmp);
234 cache_fresh_locked(tmp, new->expiry_time, detail);
235 cache_fresh_locked(old, 0, detail);
236 spin_unlock(&detail->hash_lock);
237 cache_fresh_unlocked(tmp, detail);
238 cache_fresh_unlocked(old, detail);
239 cache_put(old, detail);
240 return tmp;
241}
242EXPORT_SYMBOL_GPL(sunrpc_cache_update);
243
244static inline int cache_is_valid(struct cache_head *h)
245{
246 if (!test_bit(CACHE_VALID, &h->flags))
247 return -EAGAIN;
248 else {
249 /* entry is valid */
250 if (test_bit(CACHE_NEGATIVE, &h->flags))
251 return -ENOENT;
252 else {
253 /*
254 * In combination with write barrier in
255 * sunrpc_cache_update, ensures that anyone
256 * using the cache entry after this sees the
257 * updated contents:
258 */
259 smp_rmb();
260 return 0;
261 }
262 }
263}
264
265static int try_to_negate_entry(struct cache_detail *detail, struct cache_head *h)
266{
267 int rv;
268
269 spin_lock(&detail->hash_lock);
270 rv = cache_is_valid(h);
271 if (rv == -EAGAIN) {
272 cache_make_negative(detail, h);
273 cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY,
274 detail);
275 rv = -ENOENT;
276 }
277 spin_unlock(&detail->hash_lock);
278 cache_fresh_unlocked(h, detail);
279 return rv;
280}
281
282/*
283 * This is the generic cache management routine for all
284 * the authentication caches.
285 * It checks the currency of a cache item and will (later)
286 * initiate an upcall to fill it if needed.
287 *
288 *
289 * Returns 0 if the cache_head can be used, or cache_puts it and returns
290 * -EAGAIN if upcall is pending and request has been queued
291 * -ETIMEDOUT if upcall failed or request could not be queue or
292 * upcall completed but item is still invalid (implying that
293 * the cache item has been replaced with a newer one).
294 * -ENOENT if cache entry was negative
295 */
296int cache_check(struct cache_detail *detail,
297 struct cache_head *h, struct cache_req *rqstp)
298{
299 int rv;
300 time64_t refresh_age, age;
301
302 /* First decide return status as best we can */
303 rv = cache_is_valid(h);
304
305 /* now see if we want to start an upcall */
306 refresh_age = (h->expiry_time - h->last_refresh);
307 age = seconds_since_boot() - h->last_refresh;
308
309 if (rqstp == NULL) {
310 if (rv == -EAGAIN)
311 rv = -ENOENT;
312 } else if (rv == -EAGAIN ||
313 (h->expiry_time != 0 && age > refresh_age/2)) {
314 dprintk("RPC: Want update, refage=%lld, age=%lld\n",
315 refresh_age, age);
316 switch (detail->cache_upcall(detail, h)) {
317 case -EINVAL:
318 rv = try_to_negate_entry(detail, h);
319 break;
320 case -EAGAIN:
321 cache_fresh_unlocked(h, detail);
322 break;
323 }
324 }
325
326 if (rv == -EAGAIN) {
327 if (!cache_defer_req(rqstp, h)) {
328 /*
329 * Request was not deferred; handle it as best
330 * we can ourselves:
331 */
332 rv = cache_is_valid(h);
333 if (rv == -EAGAIN)
334 rv = -ETIMEDOUT;
335 }
336 }
337 if (rv)
338 cache_put(h, detail);
339 return rv;
340}
341EXPORT_SYMBOL_GPL(cache_check);
342
343/*
344 * caches need to be periodically cleaned.
345 * For this we maintain a list of cache_detail and
346 * a current pointer into that list and into the table
347 * for that entry.
348 *
349 * Each time cache_clean is called it finds the next non-empty entry
350 * in the current table and walks the list in that entry
351 * looking for entries that can be removed.
352 *
353 * An entry gets removed if:
354 * - The expiry is before current time
355 * - The last_refresh time is before the flush_time for that cache
356 *
357 * later we might drop old entries with non-NEVER expiry if that table
358 * is getting 'full' for some definition of 'full'
359 *
360 * The question of "how often to scan a table" is an interesting one
361 * and is answered in part by the use of the "nextcheck" field in the
362 * cache_detail.
363 * When a scan of a table begins, the nextcheck field is set to a time
364 * that is well into the future.
365 * While scanning, if an expiry time is found that is earlier than the
366 * current nextcheck time, nextcheck is set to that expiry time.
367 * If the flush_time is ever set to a time earlier than the nextcheck
368 * time, the nextcheck time is then set to that flush_time.
369 *
370 * A table is then only scanned if the current time is at least
371 * the nextcheck time.
372 *
373 */
374
375static LIST_HEAD(cache_list);
376static DEFINE_SPINLOCK(cache_list_lock);
377static struct cache_detail *current_detail;
378static int current_index;
379
380static void do_cache_clean(struct work_struct *work);
381static struct delayed_work cache_cleaner;
382
383void sunrpc_init_cache_detail(struct cache_detail *cd)
384{
385 spin_lock_init(&cd->hash_lock);
386 INIT_LIST_HEAD(&cd->queue);
387 spin_lock(&cache_list_lock);
388 cd->nextcheck = 0;
389 cd->entries = 0;
390 atomic_set(&cd->writers, 0);
391 cd->last_close = 0;
392 cd->last_warn = -1;
393 list_add(&cd->others, &cache_list);
394 spin_unlock(&cache_list_lock);
395
396 /* start the cleaning process */
397 queue_delayed_work(system_power_efficient_wq, &cache_cleaner, 0);
398}
399EXPORT_SYMBOL_GPL(sunrpc_init_cache_detail);
400
401void sunrpc_destroy_cache_detail(struct cache_detail *cd)
402{
403 cache_purge(cd);
404 spin_lock(&cache_list_lock);
405 spin_lock(&cd->hash_lock);
406 if (current_detail == cd)
407 current_detail = NULL;
408 list_del_init(&cd->others);
409 spin_unlock(&cd->hash_lock);
410 spin_unlock(&cache_list_lock);
411 if (list_empty(&cache_list)) {
412 /* module must be being unloaded so its safe to kill the worker */
413 cancel_delayed_work_sync(&cache_cleaner);
414 }
415}
416EXPORT_SYMBOL_GPL(sunrpc_destroy_cache_detail);
417
418/* clean cache tries to find something to clean
419 * and cleans it.
420 * It returns 1 if it cleaned something,
421 * 0 if it didn't find anything this time
422 * -1 if it fell off the end of the list.
423 */
424static int cache_clean(void)
425{
426 int rv = 0;
427 struct list_head *next;
428
429 spin_lock(&cache_list_lock);
430
431 /* find a suitable table if we don't already have one */
432 while (current_detail == NULL ||
433 current_index >= current_detail->hash_size) {
434 if (current_detail)
435 next = current_detail->others.next;
436 else
437 next = cache_list.next;
438 if (next == &cache_list) {
439 current_detail = NULL;
440 spin_unlock(&cache_list_lock);
441 return -1;
442 }
443 current_detail = list_entry(next, struct cache_detail, others);
444 if (current_detail->nextcheck > seconds_since_boot())
445 current_index = current_detail->hash_size;
446 else {
447 current_index = 0;
448 current_detail->nextcheck = seconds_since_boot()+30*60;
449 }
450 }
451
452 /* find a non-empty bucket in the table */
453 while (current_detail &&
454 current_index < current_detail->hash_size &&
455 hlist_empty(¤t_detail->hash_table[current_index]))
456 current_index++;
457
458 /* find a cleanable entry in the bucket and clean it, or set to next bucket */
459
460 if (current_detail && current_index < current_detail->hash_size) {
461 struct cache_head *ch = NULL;
462 struct cache_detail *d;
463 struct hlist_head *head;
464 struct hlist_node *tmp;
465
466 spin_lock(¤t_detail->hash_lock);
467
468 /* Ok, now to clean this strand */
469
470 head = ¤t_detail->hash_table[current_index];
471 hlist_for_each_entry_safe(ch, tmp, head, cache_list) {
472 if (current_detail->nextcheck > ch->expiry_time)
473 current_detail->nextcheck = ch->expiry_time+1;
474 if (!cache_is_expired(current_detail, ch))
475 continue;
476
477 sunrpc_begin_cache_remove_entry(ch, current_detail);
478 trace_cache_entry_expired(current_detail, ch);
479 rv = 1;
480 break;
481 }
482
483 spin_unlock(¤t_detail->hash_lock);
484 d = current_detail;
485 if (!ch)
486 current_index ++;
487 spin_unlock(&cache_list_lock);
488 if (ch)
489 sunrpc_end_cache_remove_entry(ch, d);
490 } else
491 spin_unlock(&cache_list_lock);
492
493 return rv;
494}
495
496/*
497 * We want to regularly clean the cache, so we need to schedule some work ...
498 */
499static void do_cache_clean(struct work_struct *work)
500{
501 int delay;
502
503 if (list_empty(&cache_list))
504 return;
505
506 if (cache_clean() == -1)
507 delay = round_jiffies_relative(30*HZ);
508 else
509 delay = 5;
510
511 queue_delayed_work(system_power_efficient_wq, &cache_cleaner, delay);
512}
513
514
515/*
516 * Clean all caches promptly. This just calls cache_clean
517 * repeatedly until we are sure that every cache has had a chance to
518 * be fully cleaned
519 */
520void cache_flush(void)
521{
522 while (cache_clean() != -1)
523 cond_resched();
524 while (cache_clean() != -1)
525 cond_resched();
526}
527EXPORT_SYMBOL_GPL(cache_flush);
528
529void cache_purge(struct cache_detail *detail)
530{
531 struct cache_head *ch = NULL;
532 struct hlist_head *head = NULL;
533 int i = 0;
534
535 spin_lock(&detail->hash_lock);
536 if (!detail->entries) {
537 spin_unlock(&detail->hash_lock);
538 return;
539 }
540
541 dprintk("RPC: %d entries in %s cache\n", detail->entries, detail->name);
542 for (i = 0; i < detail->hash_size; i++) {
543 head = &detail->hash_table[i];
544 while (!hlist_empty(head)) {
545 ch = hlist_entry(head->first, struct cache_head,
546 cache_list);
547 sunrpc_begin_cache_remove_entry(ch, detail);
548 spin_unlock(&detail->hash_lock);
549 sunrpc_end_cache_remove_entry(ch, detail);
550 spin_lock(&detail->hash_lock);
551 }
552 }
553 spin_unlock(&detail->hash_lock);
554}
555EXPORT_SYMBOL_GPL(cache_purge);
556
557
558/*
559 * Deferral and Revisiting of Requests.
560 *
561 * If a cache lookup finds a pending entry, we
562 * need to defer the request and revisit it later.
563 * All deferred requests are stored in a hash table,
564 * indexed by "struct cache_head *".
565 * As it may be wasteful to store a whole request
566 * structure, we allow the request to provide a
567 * deferred form, which must contain a
568 * 'struct cache_deferred_req'
569 * This cache_deferred_req contains a method to allow
570 * it to be revisited when cache info is available
571 */
572
573#define DFR_HASHSIZE (PAGE_SIZE/sizeof(struct list_head))
574#define DFR_HASH(item) ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE)
575
576#define DFR_MAX 300 /* ??? */
577
578static DEFINE_SPINLOCK(cache_defer_lock);
579static LIST_HEAD(cache_defer_list);
580static struct hlist_head cache_defer_hash[DFR_HASHSIZE];
581static int cache_defer_cnt;
582
583static void __unhash_deferred_req(struct cache_deferred_req *dreq)
584{
585 hlist_del_init(&dreq->hash);
586 if (!list_empty(&dreq->recent)) {
587 list_del_init(&dreq->recent);
588 cache_defer_cnt--;
589 }
590}
591
592static void __hash_deferred_req(struct cache_deferred_req *dreq, struct cache_head *item)
593{
594 int hash = DFR_HASH(item);
595
596 INIT_LIST_HEAD(&dreq->recent);
597 hlist_add_head(&dreq->hash, &cache_defer_hash[hash]);
598}
599
600static void setup_deferral(struct cache_deferred_req *dreq,
601 struct cache_head *item,
602 int count_me)
603{
604
605 dreq->item = item;
606
607 spin_lock(&cache_defer_lock);
608
609 __hash_deferred_req(dreq, item);
610
611 if (count_me) {
612 cache_defer_cnt++;
613 list_add(&dreq->recent, &cache_defer_list);
614 }
615
616 spin_unlock(&cache_defer_lock);
617
618}
619
620struct thread_deferred_req {
621 struct cache_deferred_req handle;
622 struct completion completion;
623};
624
625static void cache_restart_thread(struct cache_deferred_req *dreq, int too_many)
626{
627 struct thread_deferred_req *dr =
628 container_of(dreq, struct thread_deferred_req, handle);
629 complete(&dr->completion);
630}
631
632static void cache_wait_req(struct cache_req *req, struct cache_head *item)
633{
634 struct thread_deferred_req sleeper;
635 struct cache_deferred_req *dreq = &sleeper.handle;
636
637 sleeper.completion = COMPLETION_INITIALIZER_ONSTACK(sleeper.completion);
638 dreq->revisit = cache_restart_thread;
639
640 setup_deferral(dreq, item, 0);
641
642 if (!test_bit(CACHE_PENDING, &item->flags) ||
643 wait_for_completion_interruptible_timeout(
644 &sleeper.completion, req->thread_wait) <= 0) {
645 /* The completion wasn't completed, so we need
646 * to clean up
647 */
648 spin_lock(&cache_defer_lock);
649 if (!hlist_unhashed(&sleeper.handle.hash)) {
650 __unhash_deferred_req(&sleeper.handle);
651 spin_unlock(&cache_defer_lock);
652 } else {
653 /* cache_revisit_request already removed
654 * this from the hash table, but hasn't
655 * called ->revisit yet. It will very soon
656 * and we need to wait for it.
657 */
658 spin_unlock(&cache_defer_lock);
659 wait_for_completion(&sleeper.completion);
660 }
661 }
662}
663
664static void cache_limit_defers(void)
665{
666 /* Make sure we haven't exceed the limit of allowed deferred
667 * requests.
668 */
669 struct cache_deferred_req *discard = NULL;
670
671 if (cache_defer_cnt <= DFR_MAX)
672 return;
673
674 spin_lock(&cache_defer_lock);
675
676 /* Consider removing either the first or the last */
677 if (cache_defer_cnt > DFR_MAX) {
678 if (prandom_u32() & 1)
679 discard = list_entry(cache_defer_list.next,
680 struct cache_deferred_req, recent);
681 else
682 discard = list_entry(cache_defer_list.prev,
683 struct cache_deferred_req, recent);
684 __unhash_deferred_req(discard);
685 }
686 spin_unlock(&cache_defer_lock);
687 if (discard)
688 discard->revisit(discard, 1);
689}
690
691/* Return true if and only if a deferred request is queued. */
692static bool cache_defer_req(struct cache_req *req, struct cache_head *item)
693{
694 struct cache_deferred_req *dreq;
695
696 if (req->thread_wait) {
697 cache_wait_req(req, item);
698 if (!test_bit(CACHE_PENDING, &item->flags))
699 return false;
700 }
701 dreq = req->defer(req);
702 if (dreq == NULL)
703 return false;
704 setup_deferral(dreq, item, 1);
705 if (!test_bit(CACHE_PENDING, &item->flags))
706 /* Bit could have been cleared before we managed to
707 * set up the deferral, so need to revisit just in case
708 */
709 cache_revisit_request(item);
710
711 cache_limit_defers();
712 return true;
713}
714
715static void cache_revisit_request(struct cache_head *item)
716{
717 struct cache_deferred_req *dreq;
718 struct list_head pending;
719 struct hlist_node *tmp;
720 int hash = DFR_HASH(item);
721
722 INIT_LIST_HEAD(&pending);
723 spin_lock(&cache_defer_lock);
724
725 hlist_for_each_entry_safe(dreq, tmp, &cache_defer_hash[hash], hash)
726 if (dreq->item == item) {
727 __unhash_deferred_req(dreq);
728 list_add(&dreq->recent, &pending);
729 }
730
731 spin_unlock(&cache_defer_lock);
732
733 while (!list_empty(&pending)) {
734 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
735 list_del_init(&dreq->recent);
736 dreq->revisit(dreq, 0);
737 }
738}
739
740void cache_clean_deferred(void *owner)
741{
742 struct cache_deferred_req *dreq, *tmp;
743 struct list_head pending;
744
745
746 INIT_LIST_HEAD(&pending);
747 spin_lock(&cache_defer_lock);
748
749 list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) {
750 if (dreq->owner == owner) {
751 __unhash_deferred_req(dreq);
752 list_add(&dreq->recent, &pending);
753 }
754 }
755 spin_unlock(&cache_defer_lock);
756
757 while (!list_empty(&pending)) {
758 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
759 list_del_init(&dreq->recent);
760 dreq->revisit(dreq, 1);
761 }
762}
763
764/*
765 * communicate with user-space
766 *
767 * We have a magic /proc file - /proc/net/rpc/<cachename>/channel.
768 * On read, you get a full request, or block.
769 * On write, an update request is processed.
770 * Poll works if anything to read, and always allows write.
771 *
772 * Implemented by linked list of requests. Each open file has
773 * a ->private that also exists in this list. New requests are added
774 * to the end and may wakeup and preceding readers.
775 * New readers are added to the head. If, on read, an item is found with
776 * CACHE_UPCALLING clear, we free it from the list.
777 *
778 */
779
780static DEFINE_SPINLOCK(queue_lock);
781
782struct cache_queue {
783 struct list_head list;
784 int reader; /* if 0, then request */
785};
786struct cache_request {
787 struct cache_queue q;
788 struct cache_head *item;
789 char * buf;
790 int len;
791 int readers;
792};
793struct cache_reader {
794 struct cache_queue q;
795 int offset; /* if non-0, we have a refcnt on next request */
796};
797
798static int cache_request(struct cache_detail *detail,
799 struct cache_request *crq)
800{
801 char *bp = crq->buf;
802 int len = PAGE_SIZE;
803
804 detail->cache_request(detail, crq->item, &bp, &len);
805 if (len < 0)
806 return -EAGAIN;
807 return PAGE_SIZE - len;
808}
809
810static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
811 loff_t *ppos, struct cache_detail *cd)
812{
813 struct cache_reader *rp = filp->private_data;
814 struct cache_request *rq;
815 struct inode *inode = file_inode(filp);
816 int err;
817
818 if (count == 0)
819 return 0;
820
821 inode_lock(inode); /* protect against multiple concurrent
822 * readers on this file */
823 again:
824 spin_lock(&queue_lock);
825 /* need to find next request */
826 while (rp->q.list.next != &cd->queue &&
827 list_entry(rp->q.list.next, struct cache_queue, list)
828 ->reader) {
829 struct list_head *next = rp->q.list.next;
830 list_move(&rp->q.list, next);
831 }
832 if (rp->q.list.next == &cd->queue) {
833 spin_unlock(&queue_lock);
834 inode_unlock(inode);
835 WARN_ON_ONCE(rp->offset);
836 return 0;
837 }
838 rq = container_of(rp->q.list.next, struct cache_request, q.list);
839 WARN_ON_ONCE(rq->q.reader);
840 if (rp->offset == 0)
841 rq->readers++;
842 spin_unlock(&queue_lock);
843
844 if (rq->len == 0) {
845 err = cache_request(cd, rq);
846 if (err < 0)
847 goto out;
848 rq->len = err;
849 }
850
851 if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
852 err = -EAGAIN;
853 spin_lock(&queue_lock);
854 list_move(&rp->q.list, &rq->q.list);
855 spin_unlock(&queue_lock);
856 } else {
857 if (rp->offset + count > rq->len)
858 count = rq->len - rp->offset;
859 err = -EFAULT;
860 if (copy_to_user(buf, rq->buf + rp->offset, count))
861 goto out;
862 rp->offset += count;
863 if (rp->offset >= rq->len) {
864 rp->offset = 0;
865 spin_lock(&queue_lock);
866 list_move(&rp->q.list, &rq->q.list);
867 spin_unlock(&queue_lock);
868 }
869 err = 0;
870 }
871 out:
872 if (rp->offset == 0) {
873 /* need to release rq */
874 spin_lock(&queue_lock);
875 rq->readers--;
876 if (rq->readers == 0 &&
877 !test_bit(CACHE_PENDING, &rq->item->flags)) {
878 list_del(&rq->q.list);
879 spin_unlock(&queue_lock);
880 cache_put(rq->item, cd);
881 kfree(rq->buf);
882 kfree(rq);
883 } else
884 spin_unlock(&queue_lock);
885 }
886 if (err == -EAGAIN)
887 goto again;
888 inode_unlock(inode);
889 return err ? err : count;
890}
891
892static ssize_t cache_do_downcall(char *kaddr, const char __user *buf,
893 size_t count, struct cache_detail *cd)
894{
895 ssize_t ret;
896
897 if (count == 0)
898 return -EINVAL;
899 if (copy_from_user(kaddr, buf, count))
900 return -EFAULT;
901 kaddr[count] = '\0';
902 ret = cd->cache_parse(cd, kaddr, count);
903 if (!ret)
904 ret = count;
905 return ret;
906}
907
908static ssize_t cache_downcall(struct address_space *mapping,
909 const char __user *buf,
910 size_t count, struct cache_detail *cd)
911{
912 char *write_buf;
913 ssize_t ret = -ENOMEM;
914
915 if (count >= 32768) { /* 32k is max userland buffer, lets check anyway */
916 ret = -EINVAL;
917 goto out;
918 }
919
920 write_buf = kvmalloc(count + 1, GFP_KERNEL);
921 if (!write_buf)
922 goto out;
923
924 ret = cache_do_downcall(write_buf, buf, count, cd);
925 kvfree(write_buf);
926out:
927 return ret;
928}
929
930static ssize_t cache_write(struct file *filp, const char __user *buf,
931 size_t count, loff_t *ppos,
932 struct cache_detail *cd)
933{
934 struct address_space *mapping = filp->f_mapping;
935 struct inode *inode = file_inode(filp);
936 ssize_t ret = -EINVAL;
937
938 if (!cd->cache_parse)
939 goto out;
940
941 inode_lock(inode);
942 ret = cache_downcall(mapping, buf, count, cd);
943 inode_unlock(inode);
944out:
945 return ret;
946}
947
948static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
949
950static __poll_t cache_poll(struct file *filp, poll_table *wait,
951 struct cache_detail *cd)
952{
953 __poll_t mask;
954 struct cache_reader *rp = filp->private_data;
955 struct cache_queue *cq;
956
957 poll_wait(filp, &queue_wait, wait);
958
959 /* alway allow write */
960 mask = EPOLLOUT | EPOLLWRNORM;
961
962 if (!rp)
963 return mask;
964
965 spin_lock(&queue_lock);
966
967 for (cq= &rp->q; &cq->list != &cd->queue;
968 cq = list_entry(cq->list.next, struct cache_queue, list))
969 if (!cq->reader) {
970 mask |= EPOLLIN | EPOLLRDNORM;
971 break;
972 }
973 spin_unlock(&queue_lock);
974 return mask;
975}
976
977static int cache_ioctl(struct inode *ino, struct file *filp,
978 unsigned int cmd, unsigned long arg,
979 struct cache_detail *cd)
980{
981 int len = 0;
982 struct cache_reader *rp = filp->private_data;
983 struct cache_queue *cq;
984
985 if (cmd != FIONREAD || !rp)
986 return -EINVAL;
987
988 spin_lock(&queue_lock);
989
990 /* only find the length remaining in current request,
991 * or the length of the next request
992 */
993 for (cq= &rp->q; &cq->list != &cd->queue;
994 cq = list_entry(cq->list.next, struct cache_queue, list))
995 if (!cq->reader) {
996 struct cache_request *cr =
997 container_of(cq, struct cache_request, q);
998 len = cr->len - rp->offset;
999 break;
1000 }
1001 spin_unlock(&queue_lock);
1002
1003 return put_user(len, (int __user *)arg);
1004}
1005
1006static int cache_open(struct inode *inode, struct file *filp,
1007 struct cache_detail *cd)
1008{
1009 struct cache_reader *rp = NULL;
1010
1011 if (!cd || !try_module_get(cd->owner))
1012 return -EACCES;
1013 nonseekable_open(inode, filp);
1014 if (filp->f_mode & FMODE_READ) {
1015 rp = kmalloc(sizeof(*rp), GFP_KERNEL);
1016 if (!rp) {
1017 module_put(cd->owner);
1018 return -ENOMEM;
1019 }
1020 rp->offset = 0;
1021 rp->q.reader = 1;
1022
1023 spin_lock(&queue_lock);
1024 list_add(&rp->q.list, &cd->queue);
1025 spin_unlock(&queue_lock);
1026 }
1027 if (filp->f_mode & FMODE_WRITE)
1028 atomic_inc(&cd->writers);
1029 filp->private_data = rp;
1030 return 0;
1031}
1032
1033static int cache_release(struct inode *inode, struct file *filp,
1034 struct cache_detail *cd)
1035{
1036 struct cache_reader *rp = filp->private_data;
1037
1038 if (rp) {
1039 spin_lock(&queue_lock);
1040 if (rp->offset) {
1041 struct cache_queue *cq;
1042 for (cq= &rp->q; &cq->list != &cd->queue;
1043 cq = list_entry(cq->list.next, struct cache_queue, list))
1044 if (!cq->reader) {
1045 container_of(cq, struct cache_request, q)
1046 ->readers--;
1047 break;
1048 }
1049 rp->offset = 0;
1050 }
1051 list_del(&rp->q.list);
1052 spin_unlock(&queue_lock);
1053
1054 filp->private_data = NULL;
1055 kfree(rp);
1056
1057 }
1058 if (filp->f_mode & FMODE_WRITE) {
1059 atomic_dec(&cd->writers);
1060 cd->last_close = seconds_since_boot();
1061 }
1062 module_put(cd->owner);
1063 return 0;
1064}
1065
1066
1067
1068static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch)
1069{
1070 struct cache_queue *cq, *tmp;
1071 struct cache_request *cr;
1072 struct list_head dequeued;
1073
1074 INIT_LIST_HEAD(&dequeued);
1075 spin_lock(&queue_lock);
1076 list_for_each_entry_safe(cq, tmp, &detail->queue, list)
1077 if (!cq->reader) {
1078 cr = container_of(cq, struct cache_request, q);
1079 if (cr->item != ch)
1080 continue;
1081 if (test_bit(CACHE_PENDING, &ch->flags))
1082 /* Lost a race and it is pending again */
1083 break;
1084 if (cr->readers != 0)
1085 continue;
1086 list_move(&cr->q.list, &dequeued);
1087 }
1088 spin_unlock(&queue_lock);
1089 while (!list_empty(&dequeued)) {
1090 cr = list_entry(dequeued.next, struct cache_request, q.list);
1091 list_del(&cr->q.list);
1092 cache_put(cr->item, detail);
1093 kfree(cr->buf);
1094 kfree(cr);
1095 }
1096}
1097
1098/*
1099 * Support routines for text-based upcalls.
1100 * Fields are separated by spaces.
1101 * Fields are either mangled to quote space tab newline slosh with slosh
1102 * or a hexified with a leading \x
1103 * Record is terminated with newline.
1104 *
1105 */
1106
1107void qword_add(char **bpp, int *lp, char *str)
1108{
1109 char *bp = *bpp;
1110 int len = *lp;
1111 int ret;
1112
1113 if (len < 0) return;
1114
1115 ret = string_escape_str(str, bp, len, ESCAPE_OCTAL, "\\ \n\t");
1116 if (ret >= len) {
1117 bp += len;
1118 len = -1;
1119 } else {
1120 bp += ret;
1121 len -= ret;
1122 *bp++ = ' ';
1123 len--;
1124 }
1125 *bpp = bp;
1126 *lp = len;
1127}
1128EXPORT_SYMBOL_GPL(qword_add);
1129
1130void qword_addhex(char **bpp, int *lp, char *buf, int blen)
1131{
1132 char *bp = *bpp;
1133 int len = *lp;
1134
1135 if (len < 0) return;
1136
1137 if (len > 2) {
1138 *bp++ = '\\';
1139 *bp++ = 'x';
1140 len -= 2;
1141 while (blen && len >= 2) {
1142 bp = hex_byte_pack(bp, *buf++);
1143 len -= 2;
1144 blen--;
1145 }
1146 }
1147 if (blen || len<1) len = -1;
1148 else {
1149 *bp++ = ' ';
1150 len--;
1151 }
1152 *bpp = bp;
1153 *lp = len;
1154}
1155EXPORT_SYMBOL_GPL(qword_addhex);
1156
1157static void warn_no_listener(struct cache_detail *detail)
1158{
1159 if (detail->last_warn != detail->last_close) {
1160 detail->last_warn = detail->last_close;
1161 if (detail->warn_no_listener)
1162 detail->warn_no_listener(detail, detail->last_close != 0);
1163 }
1164}
1165
1166static bool cache_listeners_exist(struct cache_detail *detail)
1167{
1168 if (atomic_read(&detail->writers))
1169 return true;
1170 if (detail->last_close == 0)
1171 /* This cache was never opened */
1172 return false;
1173 if (detail->last_close < seconds_since_boot() - 30)
1174 /*
1175 * We allow for the possibility that someone might
1176 * restart a userspace daemon without restarting the
1177 * server; but after 30 seconds, we give up.
1178 */
1179 return false;
1180 return true;
1181}
1182
1183/*
1184 * register an upcall request to user-space and queue it up for read() by the
1185 * upcall daemon.
1186 *
1187 * Each request is at most one page long.
1188 */
1189static int cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
1190{
1191 char *buf;
1192 struct cache_request *crq;
1193 int ret = 0;
1194
1195 if (test_bit(CACHE_CLEANED, &h->flags))
1196 /* Too late to make an upcall */
1197 return -EAGAIN;
1198
1199 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1200 if (!buf)
1201 return -EAGAIN;
1202
1203 crq = kmalloc(sizeof (*crq), GFP_KERNEL);
1204 if (!crq) {
1205 kfree(buf);
1206 return -EAGAIN;
1207 }
1208
1209 crq->q.reader = 0;
1210 crq->buf = buf;
1211 crq->len = 0;
1212 crq->readers = 0;
1213 spin_lock(&queue_lock);
1214 if (test_bit(CACHE_PENDING, &h->flags)) {
1215 crq->item = cache_get(h);
1216 list_add_tail(&crq->q.list, &detail->queue);
1217 trace_cache_entry_upcall(detail, h);
1218 } else
1219 /* Lost a race, no longer PENDING, so don't enqueue */
1220 ret = -EAGAIN;
1221 spin_unlock(&queue_lock);
1222 wake_up(&queue_wait);
1223 if (ret == -EAGAIN) {
1224 kfree(buf);
1225 kfree(crq);
1226 }
1227 return ret;
1228}
1229
1230int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
1231{
1232 if (test_and_set_bit(CACHE_PENDING, &h->flags))
1233 return 0;
1234 return cache_pipe_upcall(detail, h);
1235}
1236EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall);
1237
1238int sunrpc_cache_pipe_upcall_timeout(struct cache_detail *detail,
1239 struct cache_head *h)
1240{
1241 if (!cache_listeners_exist(detail)) {
1242 warn_no_listener(detail);
1243 trace_cache_entry_no_listener(detail, h);
1244 return -EINVAL;
1245 }
1246 return sunrpc_cache_pipe_upcall(detail, h);
1247}
1248EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall_timeout);
1249
1250/*
1251 * parse a message from user-space and pass it
1252 * to an appropriate cache
1253 * Messages are, like requests, separated into fields by
1254 * spaces and dequotes as \xHEXSTRING or embedded \nnn octal
1255 *
1256 * Message is
1257 * reply cachename expiry key ... content....
1258 *
1259 * key and content are both parsed by cache
1260 */
1261
1262int qword_get(char **bpp, char *dest, int bufsize)
1263{
1264 /* return bytes copied, or -1 on error */
1265 char *bp = *bpp;
1266 int len = 0;
1267
1268 while (*bp == ' ') bp++;
1269
1270 if (bp[0] == '\\' && bp[1] == 'x') {
1271 /* HEX STRING */
1272 bp += 2;
1273 while (len < bufsize - 1) {
1274 int h, l;
1275
1276 h = hex_to_bin(bp[0]);
1277 if (h < 0)
1278 break;
1279
1280 l = hex_to_bin(bp[1]);
1281 if (l < 0)
1282 break;
1283
1284 *dest++ = (h << 4) | l;
1285 bp += 2;
1286 len++;
1287 }
1288 } else {
1289 /* text with \nnn octal quoting */
1290 while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) {
1291 if (*bp == '\\' &&
1292 isodigit(bp[1]) && (bp[1] <= '3') &&
1293 isodigit(bp[2]) &&
1294 isodigit(bp[3])) {
1295 int byte = (*++bp -'0');
1296 bp++;
1297 byte = (byte << 3) | (*bp++ - '0');
1298 byte = (byte << 3) | (*bp++ - '0');
1299 *dest++ = byte;
1300 len++;
1301 } else {
1302 *dest++ = *bp++;
1303 len++;
1304 }
1305 }
1306 }
1307
1308 if (*bp != ' ' && *bp != '\n' && *bp != '\0')
1309 return -1;
1310 while (*bp == ' ') bp++;
1311 *bpp = bp;
1312 *dest = '\0';
1313 return len;
1314}
1315EXPORT_SYMBOL_GPL(qword_get);
1316
1317
1318/*
1319 * support /proc/net/rpc/$CACHENAME/content
1320 * as a seqfile.
1321 * We call ->cache_show passing NULL for the item to
1322 * get a header, then pass each real item in the cache
1323 */
1324
1325static void *__cache_seq_start(struct seq_file *m, loff_t *pos)
1326{
1327 loff_t n = *pos;
1328 unsigned int hash, entry;
1329 struct cache_head *ch;
1330 struct cache_detail *cd = m->private;
1331
1332 if (!n--)
1333 return SEQ_START_TOKEN;
1334 hash = n >> 32;
1335 entry = n & ((1LL<<32) - 1);
1336
1337 hlist_for_each_entry_rcu(ch, &cd->hash_table[hash], cache_list)
1338 if (!entry--)
1339 return ch;
1340 n &= ~((1LL<<32) - 1);
1341 do {
1342 hash++;
1343 n += 1LL<<32;
1344 } while(hash < cd->hash_size &&
1345 hlist_empty(&cd->hash_table[hash]));
1346 if (hash >= cd->hash_size)
1347 return NULL;
1348 *pos = n+1;
1349 return hlist_entry_safe(rcu_dereference_raw(
1350 hlist_first_rcu(&cd->hash_table[hash])),
1351 struct cache_head, cache_list);
1352}
1353
1354static void *cache_seq_next(struct seq_file *m, void *p, loff_t *pos)
1355{
1356 struct cache_head *ch = p;
1357 int hash = (*pos >> 32);
1358 struct cache_detail *cd = m->private;
1359
1360 if (p == SEQ_START_TOKEN)
1361 hash = 0;
1362 else if (ch->cache_list.next == NULL) {
1363 hash++;
1364 *pos += 1LL<<32;
1365 } else {
1366 ++*pos;
1367 return hlist_entry_safe(rcu_dereference_raw(
1368 hlist_next_rcu(&ch->cache_list)),
1369 struct cache_head, cache_list);
1370 }
1371 *pos &= ~((1LL<<32) - 1);
1372 while (hash < cd->hash_size &&
1373 hlist_empty(&cd->hash_table[hash])) {
1374 hash++;
1375 *pos += 1LL<<32;
1376 }
1377 if (hash >= cd->hash_size)
1378 return NULL;
1379 ++*pos;
1380 return hlist_entry_safe(rcu_dereference_raw(
1381 hlist_first_rcu(&cd->hash_table[hash])),
1382 struct cache_head, cache_list);
1383}
1384
1385void *cache_seq_start_rcu(struct seq_file *m, loff_t *pos)
1386 __acquires(RCU)
1387{
1388 rcu_read_lock();
1389 return __cache_seq_start(m, pos);
1390}
1391EXPORT_SYMBOL_GPL(cache_seq_start_rcu);
1392
1393void *cache_seq_next_rcu(struct seq_file *file, void *p, loff_t *pos)
1394{
1395 return cache_seq_next(file, p, pos);
1396}
1397EXPORT_SYMBOL_GPL(cache_seq_next_rcu);
1398
1399void cache_seq_stop_rcu(struct seq_file *m, void *p)
1400 __releases(RCU)
1401{
1402 rcu_read_unlock();
1403}
1404EXPORT_SYMBOL_GPL(cache_seq_stop_rcu);
1405
1406static int c_show(struct seq_file *m, void *p)
1407{
1408 struct cache_head *cp = p;
1409 struct cache_detail *cd = m->private;
1410
1411 if (p == SEQ_START_TOKEN)
1412 return cd->cache_show(m, cd, NULL);
1413
1414 ifdebug(CACHE)
1415 seq_printf(m, "# expiry=%lld refcnt=%d flags=%lx\n",
1416 convert_to_wallclock(cp->expiry_time),
1417 kref_read(&cp->ref), cp->flags);
1418 cache_get(cp);
1419 if (cache_check(cd, cp, NULL))
1420 /* cache_check does a cache_put on failure */
1421 seq_puts(m, "# ");
1422 else {
1423 if (cache_is_expired(cd, cp))
1424 seq_puts(m, "# ");
1425 cache_put(cp, cd);
1426 }
1427
1428 return cd->cache_show(m, cd, cp);
1429}
1430
1431static const struct seq_operations cache_content_op = {
1432 .start = cache_seq_start_rcu,
1433 .next = cache_seq_next_rcu,
1434 .stop = cache_seq_stop_rcu,
1435 .show = c_show,
1436};
1437
1438static int content_open(struct inode *inode, struct file *file,
1439 struct cache_detail *cd)
1440{
1441 struct seq_file *seq;
1442 int err;
1443
1444 if (!cd || !try_module_get(cd->owner))
1445 return -EACCES;
1446
1447 err = seq_open(file, &cache_content_op);
1448 if (err) {
1449 module_put(cd->owner);
1450 return err;
1451 }
1452
1453 seq = file->private_data;
1454 seq->private = cd;
1455 return 0;
1456}
1457
1458static int content_release(struct inode *inode, struct file *file,
1459 struct cache_detail *cd)
1460{
1461 int ret = seq_release(inode, file);
1462 module_put(cd->owner);
1463 return ret;
1464}
1465
1466static int open_flush(struct inode *inode, struct file *file,
1467 struct cache_detail *cd)
1468{
1469 if (!cd || !try_module_get(cd->owner))
1470 return -EACCES;
1471 return nonseekable_open(inode, file);
1472}
1473
1474static int release_flush(struct inode *inode, struct file *file,
1475 struct cache_detail *cd)
1476{
1477 module_put(cd->owner);
1478 return 0;
1479}
1480
1481static ssize_t read_flush(struct file *file, char __user *buf,
1482 size_t count, loff_t *ppos,
1483 struct cache_detail *cd)
1484{
1485 char tbuf[22];
1486 size_t len;
1487
1488 len = snprintf(tbuf, sizeof(tbuf), "%llu\n",
1489 convert_to_wallclock(cd->flush_time));
1490 return simple_read_from_buffer(buf, count, ppos, tbuf, len);
1491}
1492
1493static ssize_t write_flush(struct file *file, const char __user *buf,
1494 size_t count, loff_t *ppos,
1495 struct cache_detail *cd)
1496{
1497 char tbuf[20];
1498 char *ep;
1499 time64_t now;
1500
1501 if (*ppos || count > sizeof(tbuf)-1)
1502 return -EINVAL;
1503 if (copy_from_user(tbuf, buf, count))
1504 return -EFAULT;
1505 tbuf[count] = 0;
1506 simple_strtoul(tbuf, &ep, 0);
1507 if (*ep && *ep != '\n')
1508 return -EINVAL;
1509 /* Note that while we check that 'buf' holds a valid number,
1510 * we always ignore the value and just flush everything.
1511 * Making use of the number leads to races.
1512 */
1513
1514 now = seconds_since_boot();
1515 /* Always flush everything, so behave like cache_purge()
1516 * Do this by advancing flush_time to the current time,
1517 * or by one second if it has already reached the current time.
1518 * Newly added cache entries will always have ->last_refresh greater
1519 * that ->flush_time, so they don't get flushed prematurely.
1520 */
1521
1522 if (cd->flush_time >= now)
1523 now = cd->flush_time + 1;
1524
1525 cd->flush_time = now;
1526 cd->nextcheck = now;
1527 cache_flush();
1528
1529 if (cd->flush)
1530 cd->flush();
1531
1532 *ppos += count;
1533 return count;
1534}
1535
1536static ssize_t cache_read_procfs(struct file *filp, char __user *buf,
1537 size_t count, loff_t *ppos)
1538{
1539 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1540
1541 return cache_read(filp, buf, count, ppos, cd);
1542}
1543
1544static ssize_t cache_write_procfs(struct file *filp, const char __user *buf,
1545 size_t count, loff_t *ppos)
1546{
1547 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1548
1549 return cache_write(filp, buf, count, ppos, cd);
1550}
1551
1552static __poll_t cache_poll_procfs(struct file *filp, poll_table *wait)
1553{
1554 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1555
1556 return cache_poll(filp, wait, cd);
1557}
1558
1559static long cache_ioctl_procfs(struct file *filp,
1560 unsigned int cmd, unsigned long arg)
1561{
1562 struct inode *inode = file_inode(filp);
1563 struct cache_detail *cd = PDE_DATA(inode);
1564
1565 return cache_ioctl(inode, filp, cmd, arg, cd);
1566}
1567
1568static int cache_open_procfs(struct inode *inode, struct file *filp)
1569{
1570 struct cache_detail *cd = PDE_DATA(inode);
1571
1572 return cache_open(inode, filp, cd);
1573}
1574
1575static int cache_release_procfs(struct inode *inode, struct file *filp)
1576{
1577 struct cache_detail *cd = PDE_DATA(inode);
1578
1579 return cache_release(inode, filp, cd);
1580}
1581
1582static const struct proc_ops cache_channel_proc_ops = {
1583 .proc_lseek = no_llseek,
1584 .proc_read = cache_read_procfs,
1585 .proc_write = cache_write_procfs,
1586 .proc_poll = cache_poll_procfs,
1587 .proc_ioctl = cache_ioctl_procfs, /* for FIONREAD */
1588 .proc_open = cache_open_procfs,
1589 .proc_release = cache_release_procfs,
1590};
1591
1592static int content_open_procfs(struct inode *inode, struct file *filp)
1593{
1594 struct cache_detail *cd = PDE_DATA(inode);
1595
1596 return content_open(inode, filp, cd);
1597}
1598
1599static int content_release_procfs(struct inode *inode, struct file *filp)
1600{
1601 struct cache_detail *cd = PDE_DATA(inode);
1602
1603 return content_release(inode, filp, cd);
1604}
1605
1606static const struct proc_ops content_proc_ops = {
1607 .proc_open = content_open_procfs,
1608 .proc_read = seq_read,
1609 .proc_lseek = seq_lseek,
1610 .proc_release = content_release_procfs,
1611};
1612
1613static int open_flush_procfs(struct inode *inode, struct file *filp)
1614{
1615 struct cache_detail *cd = PDE_DATA(inode);
1616
1617 return open_flush(inode, filp, cd);
1618}
1619
1620static int release_flush_procfs(struct inode *inode, struct file *filp)
1621{
1622 struct cache_detail *cd = PDE_DATA(inode);
1623
1624 return release_flush(inode, filp, cd);
1625}
1626
1627static ssize_t read_flush_procfs(struct file *filp, char __user *buf,
1628 size_t count, loff_t *ppos)
1629{
1630 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1631
1632 return read_flush(filp, buf, count, ppos, cd);
1633}
1634
1635static ssize_t write_flush_procfs(struct file *filp,
1636 const char __user *buf,
1637 size_t count, loff_t *ppos)
1638{
1639 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1640
1641 return write_flush(filp, buf, count, ppos, cd);
1642}
1643
1644static const struct proc_ops cache_flush_proc_ops = {
1645 .proc_open = open_flush_procfs,
1646 .proc_read = read_flush_procfs,
1647 .proc_write = write_flush_procfs,
1648 .proc_release = release_flush_procfs,
1649 .proc_lseek = no_llseek,
1650};
1651
1652static void remove_cache_proc_entries(struct cache_detail *cd)
1653{
1654 if (cd->procfs) {
1655 proc_remove(cd->procfs);
1656 cd->procfs = NULL;
1657 }
1658}
1659
1660#ifdef CONFIG_PROC_FS
1661static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1662{
1663 struct proc_dir_entry *p;
1664 struct sunrpc_net *sn;
1665
1666 sn = net_generic(net, sunrpc_net_id);
1667 cd->procfs = proc_mkdir(cd->name, sn->proc_net_rpc);
1668 if (cd->procfs == NULL)
1669 goto out_nomem;
1670
1671 p = proc_create_data("flush", S_IFREG | 0600,
1672 cd->procfs, &cache_flush_proc_ops, cd);
1673 if (p == NULL)
1674 goto out_nomem;
1675
1676 if (cd->cache_request || cd->cache_parse) {
1677 p = proc_create_data("channel", S_IFREG | 0600, cd->procfs,
1678 &cache_channel_proc_ops, cd);
1679 if (p == NULL)
1680 goto out_nomem;
1681 }
1682 if (cd->cache_show) {
1683 p = proc_create_data("content", S_IFREG | 0400, cd->procfs,
1684 &content_proc_ops, cd);
1685 if (p == NULL)
1686 goto out_nomem;
1687 }
1688 return 0;
1689out_nomem:
1690 remove_cache_proc_entries(cd);
1691 return -ENOMEM;
1692}
1693#else /* CONFIG_PROC_FS */
1694static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1695{
1696 return 0;
1697}
1698#endif
1699
1700void __init cache_initialize(void)
1701{
1702 INIT_DEFERRABLE_WORK(&cache_cleaner, do_cache_clean);
1703}
1704
1705int cache_register_net(struct cache_detail *cd, struct net *net)
1706{
1707 int ret;
1708
1709 sunrpc_init_cache_detail(cd);
1710 ret = create_cache_proc_entries(cd, net);
1711 if (ret)
1712 sunrpc_destroy_cache_detail(cd);
1713 return ret;
1714}
1715EXPORT_SYMBOL_GPL(cache_register_net);
1716
1717void cache_unregister_net(struct cache_detail *cd, struct net *net)
1718{
1719 remove_cache_proc_entries(cd);
1720 sunrpc_destroy_cache_detail(cd);
1721}
1722EXPORT_SYMBOL_GPL(cache_unregister_net);
1723
1724struct cache_detail *cache_create_net(const struct cache_detail *tmpl, struct net *net)
1725{
1726 struct cache_detail *cd;
1727 int i;
1728
1729 cd = kmemdup(tmpl, sizeof(struct cache_detail), GFP_KERNEL);
1730 if (cd == NULL)
1731 return ERR_PTR(-ENOMEM);
1732
1733 cd->hash_table = kcalloc(cd->hash_size, sizeof(struct hlist_head),
1734 GFP_KERNEL);
1735 if (cd->hash_table == NULL) {
1736 kfree(cd);
1737 return ERR_PTR(-ENOMEM);
1738 }
1739
1740 for (i = 0; i < cd->hash_size; i++)
1741 INIT_HLIST_HEAD(&cd->hash_table[i]);
1742 cd->net = net;
1743 return cd;
1744}
1745EXPORT_SYMBOL_GPL(cache_create_net);
1746
1747void cache_destroy_net(struct cache_detail *cd, struct net *net)
1748{
1749 kfree(cd->hash_table);
1750 kfree(cd);
1751}
1752EXPORT_SYMBOL_GPL(cache_destroy_net);
1753
1754static ssize_t cache_read_pipefs(struct file *filp, char __user *buf,
1755 size_t count, loff_t *ppos)
1756{
1757 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1758
1759 return cache_read(filp, buf, count, ppos, cd);
1760}
1761
1762static ssize_t cache_write_pipefs(struct file *filp, const 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_write(filp, buf, count, ppos, cd);
1768}
1769
1770static __poll_t cache_poll_pipefs(struct file *filp, poll_table *wait)
1771{
1772 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1773
1774 return cache_poll(filp, wait, cd);
1775}
1776
1777static long cache_ioctl_pipefs(struct file *filp,
1778 unsigned int cmd, unsigned long arg)
1779{
1780 struct inode *inode = file_inode(filp);
1781 struct cache_detail *cd = RPC_I(inode)->private;
1782
1783 return cache_ioctl(inode, filp, cmd, arg, cd);
1784}
1785
1786static int cache_open_pipefs(struct inode *inode, struct file *filp)
1787{
1788 struct cache_detail *cd = RPC_I(inode)->private;
1789
1790 return cache_open(inode, filp, cd);
1791}
1792
1793static int cache_release_pipefs(struct inode *inode, struct file *filp)
1794{
1795 struct cache_detail *cd = RPC_I(inode)->private;
1796
1797 return cache_release(inode, filp, cd);
1798}
1799
1800const struct file_operations cache_file_operations_pipefs = {
1801 .owner = THIS_MODULE,
1802 .llseek = no_llseek,
1803 .read = cache_read_pipefs,
1804 .write = cache_write_pipefs,
1805 .poll = cache_poll_pipefs,
1806 .unlocked_ioctl = cache_ioctl_pipefs, /* for FIONREAD */
1807 .open = cache_open_pipefs,
1808 .release = cache_release_pipefs,
1809};
1810
1811static int content_open_pipefs(struct inode *inode, struct file *filp)
1812{
1813 struct cache_detail *cd = RPC_I(inode)->private;
1814
1815 return content_open(inode, filp, cd);
1816}
1817
1818static int content_release_pipefs(struct inode *inode, struct file *filp)
1819{
1820 struct cache_detail *cd = RPC_I(inode)->private;
1821
1822 return content_release(inode, filp, cd);
1823}
1824
1825const struct file_operations content_file_operations_pipefs = {
1826 .open = content_open_pipefs,
1827 .read = seq_read,
1828 .llseek = seq_lseek,
1829 .release = content_release_pipefs,
1830};
1831
1832static int open_flush_pipefs(struct inode *inode, struct file *filp)
1833{
1834 struct cache_detail *cd = RPC_I(inode)->private;
1835
1836 return open_flush(inode, filp, cd);
1837}
1838
1839static int release_flush_pipefs(struct inode *inode, struct file *filp)
1840{
1841 struct cache_detail *cd = RPC_I(inode)->private;
1842
1843 return release_flush(inode, filp, cd);
1844}
1845
1846static ssize_t read_flush_pipefs(struct file *filp, char __user *buf,
1847 size_t count, loff_t *ppos)
1848{
1849 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1850
1851 return read_flush(filp, buf, count, ppos, cd);
1852}
1853
1854static ssize_t write_flush_pipefs(struct file *filp,
1855 const char __user *buf,
1856 size_t count, loff_t *ppos)
1857{
1858 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1859
1860 return write_flush(filp, buf, count, ppos, cd);
1861}
1862
1863const struct file_operations cache_flush_operations_pipefs = {
1864 .open = open_flush_pipefs,
1865 .read = read_flush_pipefs,
1866 .write = write_flush_pipefs,
1867 .release = release_flush_pipefs,
1868 .llseek = no_llseek,
1869};
1870
1871int sunrpc_cache_register_pipefs(struct dentry *parent,
1872 const char *name, umode_t umode,
1873 struct cache_detail *cd)
1874{
1875 struct dentry *dir = rpc_create_cache_dir(parent, name, umode, cd);
1876 if (IS_ERR(dir))
1877 return PTR_ERR(dir);
1878 cd->pipefs = dir;
1879 return 0;
1880}
1881EXPORT_SYMBOL_GPL(sunrpc_cache_register_pipefs);
1882
1883void sunrpc_cache_unregister_pipefs(struct cache_detail *cd)
1884{
1885 if (cd->pipefs) {
1886 rpc_remove_cache_dir(cd->pipefs);
1887 cd->pipefs = NULL;
1888 }
1889}
1890EXPORT_SYMBOL_GPL(sunrpc_cache_unregister_pipefs);
1891
1892void sunrpc_cache_unhash(struct cache_detail *cd, struct cache_head *h)
1893{
1894 spin_lock(&cd->hash_lock);
1895 if (!hlist_unhashed(&h->cache_list)){
1896 sunrpc_begin_cache_remove_entry(h, cd);
1897 spin_unlock(&cd->hash_lock);
1898 sunrpc_end_cache_remove_entry(h, cd);
1899 } else
1900 spin_unlock(&cd->hash_lock);
1901}
1902EXPORT_SYMBOL_GPL(sunrpc_cache_unhash);