1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * net/sunrpc/cache.c
4 *
5 * Generic code for various authentication-related caches
6 * used by sunrpc clients and servers.
7 *
8 * Copyright (C) 2002 Neil Brown <neilb@cse.unsw.edu.au>
9 */
10
11#include <linux/types.h>
12#include <linux/fs.h>
13#include <linux/file.h>
14#include <linux/slab.h>
15#include <linux/signal.h>
16#include <linux/sched.h>
17#include <linux/kmod.h>
18#include <linux/list.h>
19#include <linux/module.h>
20#include <linux/ctype.h>
21#include <linux/string_helpers.h>
22#include <linux/uaccess.h>
23#include <linux/poll.h>
24#include <linux/seq_file.h>
25#include <linux/proc_fs.h>
26#include <linux/net.h>
27#include <linux/workqueue.h>
28#include <linux/mutex.h>
29#include <linux/pagemap.h>
30#include <asm/ioctls.h>
31#include <linux/sunrpc/types.h>
32#include <linux/sunrpc/cache.h>
33#include <linux/sunrpc/stats.h>
34#include <linux/sunrpc/rpc_pipe_fs.h>
35#include <trace/events/sunrpc.h>
36
37#include "netns.h"
38#include "fail.h"
39
40#define RPCDBG_FACILITY RPCDBG_CACHE
41
42static bool cache_defer_req(struct cache_req *req, struct cache_head *item);
43static void cache_revisit_request(struct cache_head *item);
44
45static void cache_init(struct cache_head *h, struct cache_detail *detail)
46{
47 time64_t now = seconds_since_boot();
48 INIT_HLIST_NODE(h: &h->cache_list);
49 h->flags = 0;
50 kref_init(kref: &h->ref);
51 h->expiry_time = now + CACHE_NEW_EXPIRY;
52 if (now <= detail->flush_time)
53 /* ensure it isn't already expired */
54 now = detail->flush_time + 1;
55 h->last_refresh = now;
56}
57
58static void cache_fresh_unlocked(struct cache_head *head,
59 struct cache_detail *detail);
60
61static struct cache_head *sunrpc_cache_find_rcu(struct cache_detail *detail,
62 struct cache_head *key,
63 int hash)
64{
65 struct hlist_head *head = &detail->hash_table[hash];
66 struct cache_head *tmp;
67
68 rcu_read_lock();
69 hlist_for_each_entry_rcu(tmp, head, cache_list) {
70 if (!detail->match(tmp, key))
71 continue;
72 if (test_bit(CACHE_VALID, &tmp->flags) &&
73 cache_is_expired(detail, h: tmp))
74 continue;
75 tmp = cache_get_rcu(h: tmp);
76 rcu_read_unlock();
77 return tmp;
78 }
79 rcu_read_unlock();
80 return NULL;
81}
82
83static void sunrpc_begin_cache_remove_entry(struct cache_head *ch,
84 struct cache_detail *cd)
85{
86 /* Must be called under cd->hash_lock */
87 hlist_del_init_rcu(n: &ch->cache_list);
88 set_bit(nr: CACHE_CLEANED, addr: &ch->flags);
89 cd->entries --;
90}
91
92static void sunrpc_end_cache_remove_entry(struct cache_head *ch,
93 struct cache_detail *cd)
94{
95 cache_fresh_unlocked(head: ch, detail: cd);
96 cache_put(h: ch, cd);
97}
98
99static struct cache_head *sunrpc_cache_add_entry(struct cache_detail *detail,
100 struct cache_head *key,
101 int hash)
102{
103 struct cache_head *new, *tmp, *freeme = NULL;
104 struct hlist_head *head = &detail->hash_table[hash];
105
106 new = detail->alloc();
107 if (!new)
108 return NULL;
109 /* must fully initialise 'new', else
110 * we might get lose if we need to
111 * cache_put it soon.
112 */
113 cache_init(h: new, detail);
114 detail->init(new, key);
115
116 spin_lock(lock: &detail->hash_lock);
117
118 /* check if entry appeared while we slept */
119 hlist_for_each_entry_rcu(tmp, head, cache_list,
120 lockdep_is_held(&detail->hash_lock)) {
121 if (!detail->match(tmp, key))
122 continue;
123 if (test_bit(CACHE_VALID, &tmp->flags) &&
124 cache_is_expired(detail, h: tmp)) {
125 sunrpc_begin_cache_remove_entry(ch: tmp, cd: detail);
126 trace_cache_entry_expired(cd: detail, h: tmp);
127 freeme = tmp;
128 break;
129 }
130 cache_get(h: tmp);
131 spin_unlock(lock: &detail->hash_lock);
132 cache_put(h: new, cd: detail);
133 return tmp;
134 }
135
136 hlist_add_head_rcu(n: &new->cache_list, h: head);
137 detail->entries++;
138 if (detail->nextcheck > new->expiry_time)
139 detail->nextcheck = new->expiry_time + 1;
140 cache_get(h: new);
141 spin_unlock(lock: &detail->hash_lock);
142
143 if (freeme)
144 sunrpc_end_cache_remove_entry(ch: freeme, cd: detail);
145 return new;
146}
147
148struct cache_head *sunrpc_cache_lookup_rcu(struct cache_detail *detail,
149 struct cache_head *key, int hash)
150{
151 struct cache_head *ret;
152
153 ret = sunrpc_cache_find_rcu(detail, key, hash);
154 if (ret)
155 return ret;
156 /* Didn't find anything, insert an empty entry */
157 return sunrpc_cache_add_entry(detail, key, hash);
158}
159EXPORT_SYMBOL_GPL(sunrpc_cache_lookup_rcu);
160
161static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch);
162
163static void cache_fresh_locked(struct cache_head *head, time64_t expiry,
164 struct cache_detail *detail)
165{
166 time64_t now = seconds_since_boot();
167 if (now <= detail->flush_time)
168 /* ensure it isn't immediately treated as expired */
169 now = detail->flush_time + 1;
170 head->expiry_time = expiry;
171 head->last_refresh = now;
172 smp_wmb(); /* paired with smp_rmb() in cache_is_valid() */
173 set_bit(nr: CACHE_VALID, addr: &head->flags);
174}
175
176static void cache_fresh_unlocked(struct cache_head *head,
177 struct cache_detail *detail)
178{
179 if (test_and_clear_bit(nr: CACHE_PENDING, addr: &head->flags)) {
180 cache_revisit_request(item: head);
181 cache_dequeue(detail, ch: head);
182 }
183}
184
185static void cache_make_negative(struct cache_detail *detail,
186 struct cache_head *h)
187{
188 set_bit(nr: CACHE_NEGATIVE, addr: &h->flags);
189 trace_cache_entry_make_negative(cd: detail, h);
190}
191
192static void cache_entry_update(struct cache_detail *detail,
193 struct cache_head *h,
194 struct cache_head *new)
195{
196 if (!test_bit(CACHE_NEGATIVE, &new->flags)) {
197 detail->update(h, new);
198 trace_cache_entry_update(cd: detail, h);
199 } else {
200 cache_make_negative(detail, h);
201 }
202}
203
204struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
205 struct cache_head *new, struct cache_head *old, int hash)
206{
207 /* The 'old' entry is to be replaced by 'new'.
208 * If 'old' is not VALID, we update it directly,
209 * otherwise we need to replace it
210 */
211 struct cache_head *tmp;
212
213 if (!test_bit(CACHE_VALID, &old->flags)) {
214 spin_lock(lock: &detail->hash_lock);
215 if (!test_bit(CACHE_VALID, &old->flags)) {
216 cache_entry_update(detail, h: old, new);
217 cache_fresh_locked(head: old, expiry: new->expiry_time, detail);
218 spin_unlock(lock: &detail->hash_lock);
219 cache_fresh_unlocked(head: old, detail);
220 return old;
221 }
222 spin_unlock(lock: &detail->hash_lock);
223 }
224 /* We need to insert a new entry */
225 tmp = detail->alloc();
226 if (!tmp) {
227 cache_put(h: old, cd: detail);
228 return NULL;
229 }
230 cache_init(h: tmp, detail);
231 detail->init(tmp, old);
232
233 spin_lock(lock: &detail->hash_lock);
234 cache_entry_update(detail, h: tmp, new);
235 hlist_add_head(n: &tmp->cache_list, h: &detail->hash_table[hash]);
236 detail->entries++;
237 cache_get(h: tmp);
238 cache_fresh_locked(head: tmp, expiry: new->expiry_time, detail);
239 cache_fresh_locked(head: old, expiry: 0, detail);
240 spin_unlock(lock: &detail->hash_lock);
241 cache_fresh_unlocked(head: tmp, detail);
242 cache_fresh_unlocked(head: old, detail);
243 cache_put(h: old, cd: detail);
244 return tmp;
245}
246EXPORT_SYMBOL_GPL(sunrpc_cache_update);
247
248static inline int cache_is_valid(struct cache_head *h)
249{
250 if (!test_bit(CACHE_VALID, &h->flags))
251 return -EAGAIN;
252 else {
253 /* entry is valid */
254 if (test_bit(CACHE_NEGATIVE, &h->flags))
255 return -ENOENT;
256 else {
257 /*
258 * In combination with write barrier in
259 * sunrpc_cache_update, ensures that anyone
260 * using the cache entry after this sees the
261 * updated contents:
262 */
263 smp_rmb();
264 return 0;
265 }
266 }
267}
268
269static int try_to_negate_entry(struct cache_detail *detail, struct cache_head *h)
270{
271 int rv;
272
273 spin_lock(lock: &detail->hash_lock);
274 rv = cache_is_valid(h);
275 if (rv == -EAGAIN) {
276 cache_make_negative(detail, h);
277 cache_fresh_locked(head: h, expiry: seconds_since_boot()+CACHE_NEW_EXPIRY,
278 detail);
279 rv = -ENOENT;
280 }
281 spin_unlock(lock: &detail->hash_lock);
282 cache_fresh_unlocked(head: h, detail);
283 return rv;
284}
285
286int cache_check_rcu(struct cache_detail *detail,
287 struct cache_head *h, struct cache_req *rqstp)
288{
289 int rv;
290 time64_t refresh_age, age;
291
292 /* First decide return status as best we can */
293 rv = cache_is_valid(h);
294
295 /* now see if we want to start an upcall */
296 refresh_age = (h->expiry_time - h->last_refresh);
297 age = seconds_since_boot() - h->last_refresh;
298
299 if (rqstp == NULL) {
300 if (rv == -EAGAIN)
301 rv = -ENOENT;
302 } else if (rv == -EAGAIN ||
303 (h->expiry_time != 0 && age > refresh_age/2)) {
304 dprintk("RPC: Want update, refage=%lld, age=%lld\n",
305 refresh_age, age);
306 switch (detail->cache_upcall(detail, h)) {
307 case -EINVAL:
308 rv = try_to_negate_entry(detail, h);
309 break;
310 case -EAGAIN:
311 cache_fresh_unlocked(head: h, detail);
312 break;
313 }
314 }
315
316 if (rv == -EAGAIN) {
317 if (!cache_defer_req(req: rqstp, item: h)) {
318 /*
319 * Request was not deferred; handle it as best
320 * we can ourselves:
321 */
322 rv = cache_is_valid(h);
323 if (rv == -EAGAIN)
324 rv = -ETIMEDOUT;
325 }
326 }
327
328 return rv;
329}
330EXPORT_SYMBOL_GPL(cache_check_rcu);
331
332/*
333 * This is the generic cache management routine for all
334 * the authentication caches.
335 * It checks the currency of a cache item and will (later)
336 * initiate an upcall to fill it if needed.
337 *
338 *
339 * Returns 0 if the cache_head can be used, or cache_puts it and returns
340 * -EAGAIN if upcall is pending and request has been queued
341 * -ETIMEDOUT if upcall failed or request could not be queue or
342 * upcall completed but item is still invalid (implying that
343 * the cache item has been replaced with a newer one).
344 * -ENOENT if cache entry was negative
345 */
346int cache_check(struct cache_detail *detail,
347 struct cache_head *h, struct cache_req *rqstp)
348{
349 int rv;
350
351 rv = cache_check_rcu(detail, h, rqstp);
352 if (rv)
353 cache_put(h, cd: detail);
354 return rv;
355}
356EXPORT_SYMBOL_GPL(cache_check);
357
358/*
359 * caches need to be periodically cleaned.
360 * For this we maintain a list of cache_detail and
361 * a current pointer into that list and into the table
362 * for that entry.
363 *
364 * Each time cache_clean is called it finds the next non-empty entry
365 * in the current table and walks the list in that entry
366 * looking for entries that can be removed.
367 *
368 * An entry gets removed if:
369 * - The expiry is before current time
370 * - The last_refresh time is before the flush_time for that cache
371 *
372 * later we might drop old entries with non-NEVER expiry if that table
373 * is getting 'full' for some definition of 'full'
374 *
375 * The question of "how often to scan a table" is an interesting one
376 * and is answered in part by the use of the "nextcheck" field in the
377 * cache_detail.
378 * When a scan of a table begins, the nextcheck field is set to a time
379 * that is well into the future.
380 * While scanning, if an expiry time is found that is earlier than the
381 * current nextcheck time, nextcheck is set to that expiry time.
382 * If the flush_time is ever set to a time earlier than the nextcheck
383 * time, the nextcheck time is then set to that flush_time.
384 *
385 * A table is then only scanned if the current time is at least
386 * the nextcheck time.
387 *
388 */
389
390static LIST_HEAD(cache_list);
391static DEFINE_SPINLOCK(cache_list_lock);
392static struct cache_detail *current_detail;
393static int current_index;
394
395static void do_cache_clean(struct work_struct *work);
396static struct delayed_work cache_cleaner;
397
398void sunrpc_init_cache_detail(struct cache_detail *cd)
399{
400 spin_lock_init(&cd->hash_lock);
401 INIT_LIST_HEAD(list: &cd->queue);
402 spin_lock(lock: &cache_list_lock);
403 cd->nextcheck = 0;
404 cd->entries = 0;
405 atomic_set(v: &cd->writers, i: 0);
406 cd->last_close = 0;
407 cd->last_warn = -1;
408 list_add(new: &cd->others, head: &cache_list);
409 spin_unlock(lock: &cache_list_lock);
410
411 /* start the cleaning process */
412 queue_delayed_work(wq: system_power_efficient_wq, dwork: &cache_cleaner, delay: 0);
413}
414EXPORT_SYMBOL_GPL(sunrpc_init_cache_detail);
415
416void sunrpc_destroy_cache_detail(struct cache_detail *cd)
417{
418 cache_purge(detail: cd);
419 spin_lock(lock: &cache_list_lock);
420 spin_lock(lock: &cd->hash_lock);
421 if (current_detail == cd)
422 current_detail = NULL;
423 list_del_init(entry: &cd->others);
424 spin_unlock(lock: &cd->hash_lock);
425 spin_unlock(lock: &cache_list_lock);
426 if (list_empty(head: &cache_list)) {
427 /* module must be being unloaded so its safe to kill the worker */
428 cancel_delayed_work_sync(dwork: &cache_cleaner);
429 }
430}
431EXPORT_SYMBOL_GPL(sunrpc_destroy_cache_detail);
432
433/* clean cache tries to find something to clean
434 * and cleans it.
435 * It returns 1 if it cleaned something,
436 * 0 if it didn't find anything this time
437 * -1 if it fell off the end of the list.
438 */
439static int cache_clean(void)
440{
441 int rv = 0;
442 struct list_head *next;
443
444 spin_lock(lock: &cache_list_lock);
445
446 /* find a suitable table if we don't already have one */
447 while (current_detail == NULL ||
448 current_index >= current_detail->hash_size) {
449 if (current_detail)
450 next = current_detail->others.next;
451 else
452 next = cache_list.next;
453 if (next == &cache_list) {
454 current_detail = NULL;
455 spin_unlock(lock: &cache_list_lock);
456 return -1;
457 }
458 current_detail = list_entry(next, struct cache_detail, others);
459 if (current_detail->nextcheck > seconds_since_boot())
460 current_index = current_detail->hash_size;
461 else {
462 current_index = 0;
463 current_detail->nextcheck = seconds_since_boot()+30*60;
464 }
465 }
466
467 spin_lock(lock: &current_detail->hash_lock);
468
469 /* find a non-empty bucket in the table */
470 while (current_index < current_detail->hash_size &&
471 hlist_empty(h: &current_detail->hash_table[current_index]))
472 current_index++;
473
474 /* find a cleanable entry in the bucket and clean it, or set to next bucket */
475 if (current_index < current_detail->hash_size) {
476 struct cache_head *ch = NULL;
477 struct cache_detail *d;
478 struct hlist_head *head;
479 struct hlist_node *tmp;
480
481 /* Ok, now to clean this strand */
482 head = &current_detail->hash_table[current_index];
483 hlist_for_each_entry_safe(ch, tmp, head, cache_list) {
484 if (current_detail->nextcheck > ch->expiry_time)
485 current_detail->nextcheck = ch->expiry_time+1;
486 if (!cache_is_expired(detail: current_detail, h: ch))
487 continue;
488
489 sunrpc_begin_cache_remove_entry(ch, cd: current_detail);
490 trace_cache_entry_expired(cd: current_detail, h: ch);
491 rv = 1;
492 break;
493 }
494
495 spin_unlock(lock: &current_detail->hash_lock);
496 d = current_detail;
497 if (!ch)
498 current_index ++;
499 spin_unlock(lock: &cache_list_lock);
500 if (ch)
501 sunrpc_end_cache_remove_entry(ch, cd: d);
502 } else {
503 spin_unlock(lock: &current_detail->hash_lock);
504 spin_unlock(lock: &cache_list_lock);
505 }
506
507 return rv;
508}
509
510/*
511 * We want to regularly clean the cache, so we need to schedule some work ...
512 */
513static void do_cache_clean(struct work_struct *work)
514{
515 int delay;
516
517 if (list_empty(head: &cache_list))
518 return;
519
520 if (cache_clean() == -1)
521 delay = round_jiffies_relative(j: 30*HZ);
522 else
523 delay = 5;
524
525 queue_delayed_work(wq: system_power_efficient_wq, dwork: &cache_cleaner, delay);
526}
527
528
529/*
530 * Clean all caches promptly. This just calls cache_clean
531 * repeatedly until we are sure that every cache has had a chance to
532 * be fully cleaned
533 */
534void cache_flush(void)
535{
536 while (cache_clean() != -1)
537 cond_resched();
538 while (cache_clean() != -1)
539 cond_resched();
540}
541EXPORT_SYMBOL_GPL(cache_flush);
542
543void cache_purge(struct cache_detail *detail)
544{
545 struct cache_head *ch = NULL;
546 struct hlist_head *head = NULL;
547 int i = 0;
548
549 spin_lock(lock: &detail->hash_lock);
550 if (!detail->entries) {
551 spin_unlock(lock: &detail->hash_lock);
552 return;
553 }
554
555 dprintk("RPC: %d entries in %s cache\n", detail->entries, detail->name);
556 for (i = 0; i < detail->hash_size; i++) {
557 head = &detail->hash_table[i];
558 while (!hlist_empty(h: head)) {
559 ch = hlist_entry(head->first, struct cache_head,
560 cache_list);
561 sunrpc_begin_cache_remove_entry(ch, cd: detail);
562 spin_unlock(lock: &detail->hash_lock);
563 sunrpc_end_cache_remove_entry(ch, cd: detail);
564 spin_lock(lock: &detail->hash_lock);
565 }
566 }
567 spin_unlock(lock: &detail->hash_lock);
568}
569EXPORT_SYMBOL_GPL(cache_purge);
570
571
572/*
573 * Deferral and Revisiting of Requests.
574 *
575 * If a cache lookup finds a pending entry, we
576 * need to defer the request and revisit it later.
577 * All deferred requests are stored in a hash table,
578 * indexed by "struct cache_head *".
579 * As it may be wasteful to store a whole request
580 * structure, we allow the request to provide a
581 * deferred form, which must contain a
582 * 'struct cache_deferred_req'
583 * This cache_deferred_req contains a method to allow
584 * it to be revisited when cache info is available
585 */
586
587#define DFR_HASHSIZE (PAGE_SIZE/sizeof(struct list_head))
588#define DFR_HASH(item) ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE)
589
590#define DFR_MAX 300 /* ??? */
591
592static DEFINE_SPINLOCK(cache_defer_lock);
593static LIST_HEAD(cache_defer_list);
594static struct hlist_head cache_defer_hash[DFR_HASHSIZE];
595static int cache_defer_cnt;
596
597static void __unhash_deferred_req(struct cache_deferred_req *dreq)
598{
599 hlist_del_init(n: &dreq->hash);
600 if (!list_empty(head: &dreq->recent)) {
601 list_del_init(entry: &dreq->recent);
602 cache_defer_cnt--;
603 }
604}
605
606static void __hash_deferred_req(struct cache_deferred_req *dreq, struct cache_head *item)
607{
608 int hash = DFR_HASH(item);
609
610 INIT_LIST_HEAD(list: &dreq->recent);
611 hlist_add_head(n: &dreq->hash, h: &cache_defer_hash[hash]);
612}
613
614static void setup_deferral(struct cache_deferred_req *dreq,
615 struct cache_head *item,
616 int count_me)
617{
618
619 dreq->item = item;
620
621 spin_lock(lock: &cache_defer_lock);
622
623 __hash_deferred_req(dreq, item);
624
625 if (count_me) {
626 cache_defer_cnt++;
627 list_add(new: &dreq->recent, head: &cache_defer_list);
628 }
629
630 spin_unlock(lock: &cache_defer_lock);
631
632}
633
634struct thread_deferred_req {
635 struct cache_deferred_req handle;
636 struct completion completion;
637};
638
639static void cache_restart_thread(struct cache_deferred_req *dreq, int too_many)
640{
641 struct thread_deferred_req *dr =
642 container_of(dreq, struct thread_deferred_req, handle);
643 complete(&dr->completion);
644}
645
646static void cache_wait_req(struct cache_req *req, struct cache_head *item)
647{
648 struct thread_deferred_req sleeper;
649 struct cache_deferred_req *dreq = &sleeper.handle;
650
651 sleeper.completion = COMPLETION_INITIALIZER_ONSTACK(sleeper.completion);
652 dreq->revisit = cache_restart_thread;
653
654 setup_deferral(dreq, item, count_me: 0);
655
656 if (!test_bit(CACHE_PENDING, &item->flags) ||
657 wait_for_completion_interruptible_timeout(
658 x: &sleeper.completion, timeout: req->thread_wait) <= 0) {
659 /* The completion wasn't completed, so we need
660 * to clean up
661 */
662 spin_lock(lock: &cache_defer_lock);
663 if (!hlist_unhashed(h: &sleeper.handle.hash)) {
664 __unhash_deferred_req(dreq: &sleeper.handle);
665 spin_unlock(lock: &cache_defer_lock);
666 } else {
667 /* cache_revisit_request already removed
668 * this from the hash table, but hasn't
669 * called ->revisit yet. It will very soon
670 * and we need to wait for it.
671 */
672 spin_unlock(lock: &cache_defer_lock);
673 wait_for_completion(&sleeper.completion);
674 }
675 }
676}
677
678static void cache_limit_defers(void)
679{
680 /* Make sure we haven't exceed the limit of allowed deferred
681 * requests.
682 */
683 struct cache_deferred_req *discard = NULL;
684
685 if (cache_defer_cnt <= DFR_MAX)
686 return;
687
688 spin_lock(lock: &cache_defer_lock);
689
690 /* Consider removing either the first or the last */
691 if (cache_defer_cnt > DFR_MAX) {
692 if (get_random_u32_below(ceil: 2))
693 discard = list_entry(cache_defer_list.next,
694 struct cache_deferred_req, recent);
695 else
696 discard = list_entry(cache_defer_list.prev,
697 struct cache_deferred_req, recent);
698 __unhash_deferred_req(dreq: discard);
699 }
700 spin_unlock(lock: &cache_defer_lock);
701 if (discard)
702 discard->revisit(discard, 1);
703}
704
705#if IS_ENABLED(CONFIG_FAIL_SUNRPC)
706static inline bool cache_defer_immediately(void)
707{
708 return !fail_sunrpc.ignore_cache_wait &&
709 should_fail(&fail_sunrpc.attr, 1);
710}
711#else
712static inline bool cache_defer_immediately(void)
713{
714 return false;
715}
716#endif
717
718/* Return true if and only if a deferred request is queued. */
719static bool cache_defer_req(struct cache_req *req, struct cache_head *item)
720{
721 struct cache_deferred_req *dreq;
722
723 if (!cache_defer_immediately()) {
724 cache_wait_req(req, item);
725 if (!test_bit(CACHE_PENDING, &item->flags))
726 return false;
727 }
728
729 dreq = req->defer(req);
730 if (dreq == NULL)
731 return false;
732 setup_deferral(dreq, item, count_me: 1);
733 if (!test_bit(CACHE_PENDING, &item->flags))
734 /* Bit could have been cleared before we managed to
735 * set up the deferral, so need to revisit just in case
736 */
737 cache_revisit_request(item);
738
739 cache_limit_defers();
740 return true;
741}
742
743static void cache_revisit_request(struct cache_head *item)
744{
745 struct cache_deferred_req *dreq;
746 struct hlist_node *tmp;
747 int hash = DFR_HASH(item);
748 LIST_HEAD(pending);
749
750 spin_lock(lock: &cache_defer_lock);
751
752 hlist_for_each_entry_safe(dreq, tmp, &cache_defer_hash[hash], hash)
753 if (dreq->item == item) {
754 __unhash_deferred_req(dreq);
755 list_add(new: &dreq->recent, head: &pending);
756 }
757
758 spin_unlock(lock: &cache_defer_lock);
759
760 while (!list_empty(head: &pending)) {
761 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
762 list_del_init(entry: &dreq->recent);
763 dreq->revisit(dreq, 0);
764 }
765}
766
767void cache_clean_deferred(void *owner)
768{
769 struct cache_deferred_req *dreq, *tmp;
770 LIST_HEAD(pending);
771
772 spin_lock(lock: &cache_defer_lock);
773
774 list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) {
775 if (dreq->owner == owner) {
776 __unhash_deferred_req(dreq);
777 list_add(new: &dreq->recent, head: &pending);
778 }
779 }
780 spin_unlock(lock: &cache_defer_lock);
781
782 while (!list_empty(head: &pending)) {
783 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
784 list_del_init(entry: &dreq->recent);
785 dreq->revisit(dreq, 1);
786 }
787}
788
789/*
790 * communicate with user-space
791 *
792 * We have a magic /proc file - /proc/net/rpc/<cachename>/channel.
793 * On read, you get a full request, or block.
794 * On write, an update request is processed.
795 * Poll works if anything to read, and always allows write.
796 *
797 * Implemented by linked list of requests. Each open file has
798 * a ->private that also exists in this list. New requests are added
799 * to the end and may wakeup and preceding readers.
800 * New readers are added to the head. If, on read, an item is found with
801 * CACHE_UPCALLING clear, we free it from the list.
802 *
803 */
804
805static DEFINE_SPINLOCK(queue_lock);
806
807struct cache_queue {
808 struct list_head list;
809 int reader; /* if 0, then request */
810};
811struct cache_request {
812 struct cache_queue q;
813 struct cache_head *item;
814 char * buf;
815 int len;
816 int readers;
817};
818struct cache_reader {
819 struct cache_queue q;
820 int offset; /* if non-0, we have a refcnt on next request */
821};
822
823static int cache_request(struct cache_detail *detail,
824 struct cache_request *crq)
825{
826 char *bp = crq->buf;
827 int len = PAGE_SIZE;
828
829 detail->cache_request(detail, crq->item, &bp, &len);
830 if (len < 0)
831 return -E2BIG;
832 return PAGE_SIZE - len;
833}
834
835static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
836 loff_t *ppos, struct cache_detail *cd)
837{
838 struct cache_reader *rp = filp->private_data;
839 struct cache_request *rq;
840 struct inode *inode = file_inode(f: filp);
841 int err;
842
843 if (count == 0)
844 return 0;
845
846 inode_lock(inode); /* protect against multiple concurrent
847 * readers on this file */
848 again:
849 spin_lock(lock: &queue_lock);
850 /* need to find next request */
851 while (rp->q.list.next != &cd->queue &&
852 list_entry(rp->q.list.next, struct cache_queue, list)
853 ->reader) {
854 struct list_head *next = rp->q.list.next;
855 list_move(list: &rp->q.list, head: next);
856 }
857 if (rp->q.list.next == &cd->queue) {
858 spin_unlock(lock: &queue_lock);
859 inode_unlock(inode);
860 WARN_ON_ONCE(rp->offset);
861 return 0;
862 }
863 rq = container_of(rp->q.list.next, struct cache_request, q.list);
864 WARN_ON_ONCE(rq->q.reader);
865 if (rp->offset == 0)
866 rq->readers++;
867 spin_unlock(lock: &queue_lock);
868
869 if (rq->len == 0) {
870 err = cache_request(detail: cd, crq: rq);
871 if (err < 0)
872 goto out;
873 rq->len = err;
874 }
875
876 if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
877 err = -EAGAIN;
878 spin_lock(lock: &queue_lock);
879 list_move(list: &rp->q.list, head: &rq->q.list);
880 spin_unlock(lock: &queue_lock);
881 } else {
882 if (rp->offset + count > rq->len)
883 count = rq->len - rp->offset;
884 err = -EFAULT;
885 if (copy_to_user(to: buf, from: rq->buf + rp->offset, n: count))
886 goto out;
887 rp->offset += count;
888 if (rp->offset >= rq->len) {
889 rp->offset = 0;
890 spin_lock(lock: &queue_lock);
891 list_move(list: &rp->q.list, head: &rq->q.list);
892 spin_unlock(lock: &queue_lock);
893 }
894 err = 0;
895 }
896 out:
897 if (rp->offset == 0) {
898 /* need to release rq */
899 spin_lock(lock: &queue_lock);
900 rq->readers--;
901 if (rq->readers == 0 &&
902 !test_bit(CACHE_PENDING, &rq->item->flags)) {
903 list_del(entry: &rq->q.list);
904 spin_unlock(lock: &queue_lock);
905 cache_put(h: rq->item, cd);
906 kfree(objp: rq->buf);
907 kfree(objp: rq);
908 } else
909 spin_unlock(lock: &queue_lock);
910 }
911 if (err == -EAGAIN)
912 goto again;
913 inode_unlock(inode);
914 return err ? err : count;
915}
916
917static ssize_t cache_do_downcall(char *kaddr, const char __user *buf,
918 size_t count, struct cache_detail *cd)
919{
920 ssize_t ret;
921
922 if (count == 0)
923 return -EINVAL;
924 if (copy_from_user(to: kaddr, from: buf, n: count))
925 return -EFAULT;
926 kaddr[count] = '\0';
927 ret = cd->cache_parse(cd, kaddr, count);
928 if (!ret)
929 ret = count;
930 return ret;
931}
932
933static ssize_t cache_downcall(struct address_space *mapping,
934 const char __user *buf,
935 size_t count, struct cache_detail *cd)
936{
937 char *write_buf;
938 ssize_t ret = -ENOMEM;
939
940 if (count >= 32768) { /* 32k is max userland buffer, lets check anyway */
941 ret = -EINVAL;
942 goto out;
943 }
944
945 write_buf = kvmalloc(count + 1, GFP_KERNEL);
946 if (!write_buf)
947 goto out;
948
949 ret = cache_do_downcall(kaddr: write_buf, buf, count, cd);
950 kvfree(addr: write_buf);
951out:
952 return ret;
953}
954
955static ssize_t cache_write(struct file *filp, const char __user *buf,
956 size_t count, loff_t *ppos,
957 struct cache_detail *cd)
958{
959 struct address_space *mapping = filp->f_mapping;
960 struct inode *inode = file_inode(f: filp);
961 ssize_t ret = -EINVAL;
962
963 if (!cd->cache_parse)
964 goto out;
965
966 inode_lock(inode);
967 ret = cache_downcall(mapping, buf, count, cd);
968 inode_unlock(inode);
969out:
970 return ret;
971}
972
973static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
974
975static __poll_t cache_poll(struct file *filp, poll_table *wait,
976 struct cache_detail *cd)
977{
978 __poll_t mask;
979 struct cache_reader *rp = filp->private_data;
980 struct cache_queue *cq;
981
982 poll_wait(filp, wait_address: &queue_wait, p: wait);
983
984 /* alway allow write */
985 mask = EPOLLOUT | EPOLLWRNORM;
986
987 if (!rp)
988 return mask;
989
990 spin_lock(lock: &queue_lock);
991
992 for (cq= &rp->q; &cq->list != &cd->queue;
993 cq = list_entry(cq->list.next, struct cache_queue, list))
994 if (!cq->reader) {
995 mask |= EPOLLIN | EPOLLRDNORM;
996 break;
997 }
998 spin_unlock(lock: &queue_lock);
999 return mask;
1000}
1001
1002static int cache_ioctl(struct inode *ino, struct file *filp,
1003 unsigned int cmd, unsigned long arg,
1004 struct cache_detail *cd)
1005{
1006 int len = 0;
1007 struct cache_reader *rp = filp->private_data;
1008 struct cache_queue *cq;
1009
1010 if (cmd != FIONREAD || !rp)
1011 return -EINVAL;
1012
1013 spin_lock(lock: &queue_lock);
1014
1015 /* only find the length remaining in current request,
1016 * or the length of the next request
1017 */
1018 for (cq= &rp->q; &cq->list != &cd->queue;
1019 cq = list_entry(cq->list.next, struct cache_queue, list))
1020 if (!cq->reader) {
1021 struct cache_request *cr =
1022 container_of(cq, struct cache_request, q);
1023 len = cr->len - rp->offset;
1024 break;
1025 }
1026 spin_unlock(lock: &queue_lock);
1027
1028 return put_user(len, (int __user *)arg);
1029}
1030
1031static int cache_open(struct inode *inode, struct file *filp,
1032 struct cache_detail *cd)
1033{
1034 struct cache_reader *rp = NULL;
1035
1036 if (!cd || !try_module_get(module: cd->owner))
1037 return -EACCES;
1038 nonseekable_open(inode, filp);
1039 if (filp->f_mode & FMODE_READ) {
1040 rp = kmalloc(sizeof(*rp), GFP_KERNEL);
1041 if (!rp) {
1042 module_put(module: cd->owner);
1043 return -ENOMEM;
1044 }
1045 rp->offset = 0;
1046 rp->q.reader = 1;
1047
1048 spin_lock(lock: &queue_lock);
1049 list_add(new: &rp->q.list, head: &cd->queue);
1050 spin_unlock(lock: &queue_lock);
1051 }
1052 if (filp->f_mode & FMODE_WRITE)
1053 atomic_inc(v: &cd->writers);
1054 filp->private_data = rp;
1055 return 0;
1056}
1057
1058static int cache_release(struct inode *inode, struct file *filp,
1059 struct cache_detail *cd)
1060{
1061 struct cache_reader *rp = filp->private_data;
1062
1063 if (rp) {
1064 spin_lock(lock: &queue_lock);
1065 if (rp->offset) {
1066 struct cache_queue *cq;
1067 for (cq= &rp->q; &cq->list != &cd->queue;
1068 cq = list_entry(cq->list.next, struct cache_queue, list))
1069 if (!cq->reader) {
1070 container_of(cq, struct cache_request, q)
1071 ->readers--;
1072 break;
1073 }
1074 rp->offset = 0;
1075 }
1076 list_del(entry: &rp->q.list);
1077 spin_unlock(lock: &queue_lock);
1078
1079 filp->private_data = NULL;
1080 kfree(objp: rp);
1081
1082 }
1083 if (filp->f_mode & FMODE_WRITE) {
1084 atomic_dec(v: &cd->writers);
1085 cd->last_close = seconds_since_boot();
1086 }
1087 module_put(module: cd->owner);
1088 return 0;
1089}
1090
1091
1092
1093static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch)
1094{
1095 struct cache_queue *cq, *tmp;
1096 struct cache_request *cr;
1097 LIST_HEAD(dequeued);
1098
1099 spin_lock(lock: &queue_lock);
1100 list_for_each_entry_safe(cq, tmp, &detail->queue, list)
1101 if (!cq->reader) {
1102 cr = container_of(cq, struct cache_request, q);
1103 if (cr->item != ch)
1104 continue;
1105 if (test_bit(CACHE_PENDING, &ch->flags))
1106 /* Lost a race and it is pending again */
1107 break;
1108 if (cr->readers != 0)
1109 continue;
1110 list_move(list: &cr->q.list, head: &dequeued);
1111 }
1112 spin_unlock(lock: &queue_lock);
1113 while (!list_empty(head: &dequeued)) {
1114 cr = list_entry(dequeued.next, struct cache_request, q.list);
1115 list_del(entry: &cr->q.list);
1116 cache_put(h: cr->item, cd: detail);
1117 kfree(objp: cr->buf);
1118 kfree(objp: cr);
1119 }
1120}
1121
1122/*
1123 * Support routines for text-based upcalls.
1124 * Fields are separated by spaces.
1125 * Fields are either mangled to quote space tab newline slosh with slosh
1126 * or a hexified with a leading \x
1127 * Record is terminated with newline.
1128 *
1129 */
1130
1131void qword_add(char **bpp, int *lp, char *str)
1132{
1133 char *bp = *bpp;
1134 int len = *lp;
1135 int ret;
1136
1137 if (len < 0) return;
1138
1139 ret = string_escape_str(src: str, dst: bp, sz: len, ESCAPE_OCTAL, only: "\\ \n\t");
1140 if (ret >= len) {
1141 bp += len;
1142 len = -1;
1143 } else {
1144 bp += ret;
1145 len -= ret;
1146 *bp++ = ' ';
1147 len--;
1148 }
1149 *bpp = bp;
1150 *lp = len;
1151}
1152EXPORT_SYMBOL_GPL(qword_add);
1153
1154void qword_addhex(char **bpp, int *lp, char *buf, int blen)
1155{
1156 char *bp = *bpp;
1157 int len = *lp;
1158
1159 if (len < 0) return;
1160
1161 if (len > 2) {
1162 *bp++ = '\\';
1163 *bp++ = 'x';
1164 len -= 2;
1165 while (blen && len >= 2) {
1166 bp = hex_byte_pack(buf: bp, byte: *buf++);
1167 len -= 2;
1168 blen--;
1169 }
1170 }
1171 if (blen || len<1) len = -1;
1172 else {
1173 *bp++ = ' ';
1174 len--;
1175 }
1176 *bpp = bp;
1177 *lp = len;
1178}
1179EXPORT_SYMBOL_GPL(qword_addhex);
1180
1181static void warn_no_listener(struct cache_detail *detail)
1182{
1183 if (detail->last_warn != detail->last_close) {
1184 detail->last_warn = detail->last_close;
1185 if (detail->warn_no_listener)
1186 detail->warn_no_listener(detail, detail->last_close != 0);
1187 }
1188}
1189
1190static bool cache_listeners_exist(struct cache_detail *detail)
1191{
1192 if (atomic_read(v: &detail->writers))
1193 return true;
1194 if (detail->last_close == 0)
1195 /* This cache was never opened */
1196 return false;
1197 if (detail->last_close < seconds_since_boot() - 30)
1198 /*
1199 * We allow for the possibility that someone might
1200 * restart a userspace daemon without restarting the
1201 * server; but after 30 seconds, we give up.
1202 */
1203 return false;
1204 return true;
1205}
1206
1207/*
1208 * register an upcall request to user-space and queue it up for read() by the
1209 * upcall daemon.
1210 *
1211 * Each request is at most one page long.
1212 */
1213static int cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
1214{
1215 char *buf;
1216 struct cache_request *crq;
1217 int ret = 0;
1218
1219 if (test_bit(CACHE_CLEANED, &h->flags))
1220 /* Too late to make an upcall */
1221 return -EAGAIN;
1222
1223 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1224 if (!buf)
1225 return -EAGAIN;
1226
1227 crq = kmalloc(sizeof (*crq), GFP_KERNEL);
1228 if (!crq) {
1229 kfree(objp: buf);
1230 return -EAGAIN;
1231 }
1232
1233 crq->q.reader = 0;
1234 crq->buf = buf;
1235 crq->len = 0;
1236 crq->readers = 0;
1237 spin_lock(lock: &queue_lock);
1238 if (test_bit(CACHE_PENDING, &h->flags)) {
1239 crq->item = cache_get(h);
1240 list_add_tail(new: &crq->q.list, head: &detail->queue);
1241 trace_cache_entry_upcall(cd: detail, h);
1242 } else
1243 /* Lost a race, no longer PENDING, so don't enqueue */
1244 ret = -EAGAIN;
1245 spin_unlock(lock: &queue_lock);
1246 wake_up(&queue_wait);
1247 if (ret == -EAGAIN) {
1248 kfree(objp: buf);
1249 kfree(objp: crq);
1250 }
1251 return ret;
1252}
1253
1254int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
1255{
1256 if (test_and_set_bit(nr: CACHE_PENDING, addr: &h->flags))
1257 return 0;
1258 return cache_pipe_upcall(detail, h);
1259}
1260EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall);
1261
1262int sunrpc_cache_pipe_upcall_timeout(struct cache_detail *detail,
1263 struct cache_head *h)
1264{
1265 if (!cache_listeners_exist(detail)) {
1266 warn_no_listener(detail);
1267 trace_cache_entry_no_listener(cd: detail, h);
1268 return -EINVAL;
1269 }
1270 return sunrpc_cache_pipe_upcall(detail, h);
1271}
1272EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall_timeout);
1273
1274/*
1275 * parse a message from user-space and pass it
1276 * to an appropriate cache
1277 * Messages are, like requests, separated into fields by
1278 * spaces and dequotes as \xHEXSTRING or embedded \nnn octal
1279 *
1280 * Message is
1281 * reply cachename expiry key ... content....
1282 *
1283 * key and content are both parsed by cache
1284 */
1285
1286int qword_get(char **bpp, char *dest, int bufsize)
1287{
1288 /* return bytes copied, or -1 on error */
1289 char *bp = *bpp;
1290 int len = 0;
1291
1292 while (*bp == ' ') bp++;
1293
1294 if (bp[0] == '\\' && bp[1] == 'x') {
1295 /* HEX STRING */
1296 bp += 2;
1297 while (len < bufsize - 1) {
1298 int h, l;
1299
1300 h = hex_to_bin(ch: bp[0]);
1301 if (h < 0)
1302 break;
1303
1304 l = hex_to_bin(ch: bp[1]);
1305 if (l < 0)
1306 break;
1307
1308 *dest++ = (h << 4) | l;
1309 bp += 2;
1310 len++;
1311 }
1312 } else {
1313 /* text with \nnn octal quoting */
1314 while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) {
1315 if (*bp == '\\' &&
1316 isodigit(c: bp[1]) && (bp[1] <= '3') &&
1317 isodigit(c: bp[2]) &&
1318 isodigit(c: bp[3])) {
1319 int byte = (*++bp -'0');
1320 bp++;
1321 byte = (byte << 3) | (*bp++ - '0');
1322 byte = (byte << 3) | (*bp++ - '0');
1323 *dest++ = byte;
1324 len++;
1325 } else {
1326 *dest++ = *bp++;
1327 len++;
1328 }
1329 }
1330 }
1331
1332 if (*bp != ' ' && *bp != '\n' && *bp != '\0')
1333 return -1;
1334 while (*bp == ' ') bp++;
1335 *bpp = bp;
1336 *dest = '\0';
1337 return len;
1338}
1339EXPORT_SYMBOL_GPL(qword_get);
1340
1341
1342/*
1343 * support /proc/net/rpc/$CACHENAME/content
1344 * as a seqfile.
1345 * We call ->cache_show passing NULL for the item to
1346 * get a header, then pass each real item in the cache
1347 */
1348
1349static void *__cache_seq_start(struct seq_file *m, loff_t *pos)
1350{
1351 loff_t n = *pos;
1352 unsigned int hash, entry;
1353 struct cache_head *ch;
1354 struct cache_detail *cd = m->private;
1355
1356 if (!n--)
1357 return SEQ_START_TOKEN;
1358 hash = n >> 32;
1359 entry = n & ((1LL<<32) - 1);
1360
1361 hlist_for_each_entry_rcu(ch, &cd->hash_table[hash], cache_list)
1362 if (!entry--)
1363 return ch;
1364 n &= ~((1LL<<32) - 1);
1365 do {
1366 hash++;
1367 n += 1LL<<32;
1368 } while(hash < cd->hash_size &&
1369 hlist_empty(h: &cd->hash_table[hash]));
1370 if (hash >= cd->hash_size)
1371 return NULL;
1372 *pos = n+1;
1373 return hlist_entry_safe(rcu_dereference_raw(
1374 hlist_first_rcu(&cd->hash_table[hash])),
1375 struct cache_head, cache_list);
1376}
1377
1378static void *cache_seq_next(struct seq_file *m, void *p, loff_t *pos)
1379{
1380 struct cache_head *ch = p;
1381 int hash = (*pos >> 32);
1382 struct cache_detail *cd = m->private;
1383
1384 if (p == SEQ_START_TOKEN)
1385 hash = 0;
1386 else if (ch->cache_list.next == NULL) {
1387 hash++;
1388 *pos += 1LL<<32;
1389 } else {
1390 ++*pos;
1391 return hlist_entry_safe(rcu_dereference_raw(
1392 hlist_next_rcu(&ch->cache_list)),
1393 struct cache_head, cache_list);
1394 }
1395 *pos &= ~((1LL<<32) - 1);
1396 while (hash < cd->hash_size &&
1397 hlist_empty(h: &cd->hash_table[hash])) {
1398 hash++;
1399 *pos += 1LL<<32;
1400 }
1401 if (hash >= cd->hash_size)
1402 return NULL;
1403 ++*pos;
1404 return hlist_entry_safe(rcu_dereference_raw(
1405 hlist_first_rcu(&cd->hash_table[hash])),
1406 struct cache_head, cache_list);
1407}
1408
1409void *cache_seq_start_rcu(struct seq_file *m, loff_t *pos)
1410 __acquires(RCU)
1411{
1412 rcu_read_lock();
1413 return __cache_seq_start(m, pos);
1414}
1415EXPORT_SYMBOL_GPL(cache_seq_start_rcu);
1416
1417void *cache_seq_next_rcu(struct seq_file *file, void *p, loff_t *pos)
1418{
1419 return cache_seq_next(m: file, p, pos);
1420}
1421EXPORT_SYMBOL_GPL(cache_seq_next_rcu);
1422
1423void cache_seq_stop_rcu(struct seq_file *m, void *p)
1424 __releases(RCU)
1425{
1426 rcu_read_unlock();
1427}
1428EXPORT_SYMBOL_GPL(cache_seq_stop_rcu);
1429
1430static int c_show(struct seq_file *m, void *p)
1431{
1432 struct cache_head *cp = p;
1433 struct cache_detail *cd = m->private;
1434
1435 if (p == SEQ_START_TOKEN)
1436 return cd->cache_show(m, cd, NULL);
1437
1438 ifdebug(CACHE)
1439 seq_printf(m, fmt: "# expiry=%lld refcnt=%d flags=%lx\n",
1440 convert_to_wallclock(sinceboot: cp->expiry_time),
1441 kref_read(kref: &cp->ref), cp->flags);
1442
1443 if (cache_check_rcu(cd, cp, NULL))
1444 seq_puts(m, s: "# ");
1445 else if (cache_is_expired(detail: cd, h: cp))
1446 seq_puts(m, s: "# ");
1447
1448 return cd->cache_show(m, cd, cp);
1449}
1450
1451static const struct seq_operations cache_content_op = {
1452 .start = cache_seq_start_rcu,
1453 .next = cache_seq_next_rcu,
1454 .stop = cache_seq_stop_rcu,
1455 .show = c_show,
1456};
1457
1458static int content_open(struct inode *inode, struct file *file,
1459 struct cache_detail *cd)
1460{
1461 struct seq_file *seq;
1462 int err;
1463
1464 if (!cd || !try_module_get(module: cd->owner))
1465 return -EACCES;
1466
1467 err = seq_open(file, &cache_content_op);
1468 if (err) {
1469 module_put(module: cd->owner);
1470 return err;
1471 }
1472
1473 seq = file->private_data;
1474 seq->private = cd;
1475 return 0;
1476}
1477
1478static int content_release(struct inode *inode, struct file *file,
1479 struct cache_detail *cd)
1480{
1481 int ret = seq_release(inode, file);
1482 module_put(module: cd->owner);
1483 return ret;
1484}
1485
1486static int open_flush(struct inode *inode, struct file *file,
1487 struct cache_detail *cd)
1488{
1489 if (!cd || !try_module_get(module: cd->owner))
1490 return -EACCES;
1491 return nonseekable_open(inode, filp: file);
1492}
1493
1494static int release_flush(struct inode *inode, struct file *file,
1495 struct cache_detail *cd)
1496{
1497 module_put(module: cd->owner);
1498 return 0;
1499}
1500
1501static ssize_t read_flush(struct file *file, char __user *buf,
1502 size_t count, loff_t *ppos,
1503 struct cache_detail *cd)
1504{
1505 char tbuf[22];
1506 size_t len;
1507
1508 len = snprintf(buf: tbuf, size: sizeof(tbuf), fmt: "%llu\n",
1509 convert_to_wallclock(sinceboot: cd->flush_time));
1510 return simple_read_from_buffer(to: buf, count, ppos, from: tbuf, available: len);
1511}
1512
1513static ssize_t write_flush(struct file *file, const char __user *buf,
1514 size_t count, loff_t *ppos,
1515 struct cache_detail *cd)
1516{
1517 char tbuf[20];
1518 char *ep;
1519 time64_t now;
1520
1521 if (*ppos || count > sizeof(tbuf)-1)
1522 return -EINVAL;
1523 if (copy_from_user(to: tbuf, from: buf, n: count))
1524 return -EFAULT;
1525 tbuf[count] = 0;
1526 simple_strtoul(tbuf, &ep, 0);
1527 if (*ep && *ep != '\n')
1528 return -EINVAL;
1529 /* Note that while we check that 'buf' holds a valid number,
1530 * we always ignore the value and just flush everything.
1531 * Making use of the number leads to races.
1532 */
1533
1534 now = seconds_since_boot();
1535 /* Always flush everything, so behave like cache_purge()
1536 * Do this by advancing flush_time to the current time,
1537 * or by one second if it has already reached the current time.
1538 * Newly added cache entries will always have ->last_refresh greater
1539 * that ->flush_time, so they don't get flushed prematurely.
1540 */
1541
1542 if (cd->flush_time >= now)
1543 now = cd->flush_time + 1;
1544
1545 cd->flush_time = now;
1546 cd->nextcheck = now;
1547 cache_flush();
1548
1549 if (cd->flush)
1550 cd->flush();
1551
1552 *ppos += count;
1553 return count;
1554}
1555
1556static ssize_t cache_read_procfs(struct file *filp, char __user *buf,
1557 size_t count, loff_t *ppos)
1558{
1559 struct cache_detail *cd = pde_data(inode: file_inode(f: filp));
1560
1561 return cache_read(filp, buf, count, ppos, cd);
1562}
1563
1564static ssize_t cache_write_procfs(struct file *filp, const char __user *buf,
1565 size_t count, loff_t *ppos)
1566{
1567 struct cache_detail *cd = pde_data(inode: file_inode(f: filp));
1568
1569 return cache_write(filp, buf, count, ppos, cd);
1570}
1571
1572static __poll_t cache_poll_procfs(struct file *filp, poll_table *wait)
1573{
1574 struct cache_detail *cd = pde_data(inode: file_inode(f: filp));
1575
1576 return cache_poll(filp, wait, cd);
1577}
1578
1579static long cache_ioctl_procfs(struct file *filp,
1580 unsigned int cmd, unsigned long arg)
1581{
1582 struct inode *inode = file_inode(f: filp);
1583 struct cache_detail *cd = pde_data(inode);
1584
1585 return cache_ioctl(ino: inode, filp, cmd, arg, cd);
1586}
1587
1588static int cache_open_procfs(struct inode *inode, struct file *filp)
1589{
1590 struct cache_detail *cd = pde_data(inode);
1591
1592 return cache_open(inode, filp, cd);
1593}
1594
1595static int cache_release_procfs(struct inode *inode, struct file *filp)
1596{
1597 struct cache_detail *cd = pde_data(inode);
1598
1599 return cache_release(inode, filp, cd);
1600}
1601
1602static const struct proc_ops cache_channel_proc_ops = {
1603 .proc_read = cache_read_procfs,
1604 .proc_write = cache_write_procfs,
1605 .proc_poll = cache_poll_procfs,
1606 .proc_ioctl = cache_ioctl_procfs, /* for FIONREAD */
1607 .proc_open = cache_open_procfs,
1608 .proc_release = cache_release_procfs,
1609};
1610
1611static int content_open_procfs(struct inode *inode, struct file *filp)
1612{
1613 struct cache_detail *cd = pde_data(inode);
1614
1615 return content_open(inode, file: filp, cd);
1616}
1617
1618static int content_release_procfs(struct inode *inode, struct file *filp)
1619{
1620 struct cache_detail *cd = pde_data(inode);
1621
1622 return content_release(inode, file: filp, cd);
1623}
1624
1625static const struct proc_ops content_proc_ops = {
1626 .proc_open = content_open_procfs,
1627 .proc_read = seq_read,
1628 .proc_lseek = seq_lseek,
1629 .proc_release = content_release_procfs,
1630};
1631
1632static int open_flush_procfs(struct inode *inode, struct file *filp)
1633{
1634 struct cache_detail *cd = pde_data(inode);
1635
1636 return open_flush(inode, file: filp, cd);
1637}
1638
1639static int release_flush_procfs(struct inode *inode, struct file *filp)
1640{
1641 struct cache_detail *cd = pde_data(inode);
1642
1643 return release_flush(inode, file: filp, cd);
1644}
1645
1646static ssize_t read_flush_procfs(struct file *filp, char __user *buf,
1647 size_t count, loff_t *ppos)
1648{
1649 struct cache_detail *cd = pde_data(inode: file_inode(f: filp));
1650
1651 return read_flush(file: filp, buf, count, ppos, cd);
1652}
1653
1654static ssize_t write_flush_procfs(struct file *filp,
1655 const char __user *buf,
1656 size_t count, loff_t *ppos)
1657{
1658 struct cache_detail *cd = pde_data(inode: file_inode(f: filp));
1659
1660 return write_flush(file: filp, buf, count, ppos, cd);
1661}
1662
1663static const struct proc_ops cache_flush_proc_ops = {
1664 .proc_open = open_flush_procfs,
1665 .proc_read = read_flush_procfs,
1666 .proc_write = write_flush_procfs,
1667 .proc_release = release_flush_procfs,
1668};
1669
1670static void remove_cache_proc_entries(struct cache_detail *cd)
1671{
1672 if (cd->procfs) {
1673 proc_remove(cd->procfs);
1674 cd->procfs = NULL;
1675 }
1676}
1677
1678static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1679{
1680 struct proc_dir_entry *p;
1681 struct sunrpc_net *sn;
1682
1683 if (!IS_ENABLED(CONFIG_PROC_FS))
1684 return 0;
1685
1686 sn = net_generic(net, id: sunrpc_net_id);
1687 cd->procfs = proc_mkdir(cd->name, sn->proc_net_rpc);
1688 if (cd->procfs == NULL)
1689 goto out_nomem;
1690
1691 p = proc_create_data("flush", S_IFREG | 0600,
1692 cd->procfs, &cache_flush_proc_ops, cd);
1693 if (p == NULL)
1694 goto out_nomem;
1695
1696 if (cd->cache_request || cd->cache_parse) {
1697 p = proc_create_data("channel", S_IFREG | 0600, cd->procfs,
1698 &cache_channel_proc_ops, cd);
1699 if (p == NULL)
1700 goto out_nomem;
1701 }
1702 if (cd->cache_show) {
1703 p = proc_create_data("content", S_IFREG | 0400, cd->procfs,
1704 &content_proc_ops, cd);
1705 if (p == NULL)
1706 goto out_nomem;
1707 }
1708 return 0;
1709out_nomem:
1710 remove_cache_proc_entries(cd);
1711 return -ENOMEM;
1712}
1713
1714void __init cache_initialize(void)
1715{
1716 INIT_DEFERRABLE_WORK(&cache_cleaner, do_cache_clean);
1717}
1718
1719int cache_register_net(struct cache_detail *cd, struct net *net)
1720{
1721 int ret;
1722
1723 sunrpc_init_cache_detail(cd);
1724 ret = create_cache_proc_entries(cd, net);
1725 if (ret)
1726 sunrpc_destroy_cache_detail(cd);
1727 return ret;
1728}
1729EXPORT_SYMBOL_GPL(cache_register_net);
1730
1731void cache_unregister_net(struct cache_detail *cd, struct net *net)
1732{
1733 remove_cache_proc_entries(cd);
1734 sunrpc_destroy_cache_detail(cd);
1735}
1736EXPORT_SYMBOL_GPL(cache_unregister_net);
1737
1738struct cache_detail *cache_create_net(const struct cache_detail *tmpl, struct net *net)
1739{
1740 struct cache_detail *cd;
1741 int i;
1742
1743 cd = kmemdup(tmpl, sizeof(struct cache_detail), GFP_KERNEL);
1744 if (cd == NULL)
1745 return ERR_PTR(error: -ENOMEM);
1746
1747 cd->hash_table = kcalloc(cd->hash_size, sizeof(struct hlist_head),
1748 GFP_KERNEL);
1749 if (cd->hash_table == NULL) {
1750 kfree(objp: cd);
1751 return ERR_PTR(error: -ENOMEM);
1752 }
1753
1754 for (i = 0; i < cd->hash_size; i++)
1755 INIT_HLIST_HEAD(&cd->hash_table[i]);
1756 cd->net = net;
1757 return cd;
1758}
1759EXPORT_SYMBOL_GPL(cache_create_net);
1760
1761void cache_destroy_net(struct cache_detail *cd, struct net *net)
1762{
1763 kfree(objp: cd->hash_table);
1764 kfree(objp: cd);
1765}
1766EXPORT_SYMBOL_GPL(cache_destroy_net);
1767
1768static ssize_t cache_read_pipefs(struct file *filp, char __user *buf,
1769 size_t count, loff_t *ppos)
1770{
1771 struct cache_detail *cd = RPC_I(inode: file_inode(f: filp))->private;
1772
1773 return cache_read(filp, buf, count, ppos, cd);
1774}
1775
1776static ssize_t cache_write_pipefs(struct file *filp, const char __user *buf,
1777 size_t count, loff_t *ppos)
1778{
1779 struct cache_detail *cd = RPC_I(inode: file_inode(f: filp))->private;
1780
1781 return cache_write(filp, buf, count, ppos, cd);
1782}
1783
1784static __poll_t cache_poll_pipefs(struct file *filp, poll_table *wait)
1785{
1786 struct cache_detail *cd = RPC_I(inode: file_inode(f: filp))->private;
1787
1788 return cache_poll(filp, wait, cd);
1789}
1790
1791static long cache_ioctl_pipefs(struct file *filp,
1792 unsigned int cmd, unsigned long arg)
1793{
1794 struct inode *inode = file_inode(f: filp);
1795 struct cache_detail *cd = RPC_I(inode)->private;
1796
1797 return cache_ioctl(ino: inode, filp, cmd, arg, cd);
1798}
1799
1800static int cache_open_pipefs(struct inode *inode, struct file *filp)
1801{
1802 struct cache_detail *cd = RPC_I(inode)->private;
1803
1804 return cache_open(inode, filp, cd);
1805}
1806
1807static int cache_release_pipefs(struct inode *inode, struct file *filp)
1808{
1809 struct cache_detail *cd = RPC_I(inode)->private;
1810
1811 return cache_release(inode, filp, cd);
1812}
1813
1814const struct file_operations cache_file_operations_pipefs = {
1815 .owner = THIS_MODULE,
1816 .read = cache_read_pipefs,
1817 .write = cache_write_pipefs,
1818 .poll = cache_poll_pipefs,
1819 .unlocked_ioctl = cache_ioctl_pipefs, /* for FIONREAD */
1820 .open = cache_open_pipefs,
1821 .release = cache_release_pipefs,
1822};
1823
1824static int content_open_pipefs(struct inode *inode, struct file *filp)
1825{
1826 struct cache_detail *cd = RPC_I(inode)->private;
1827
1828 return content_open(inode, file: filp, cd);
1829}
1830
1831static int content_release_pipefs(struct inode *inode, struct file *filp)
1832{
1833 struct cache_detail *cd = RPC_I(inode)->private;
1834
1835 return content_release(inode, file: filp, cd);
1836}
1837
1838const struct file_operations content_file_operations_pipefs = {
1839 .open = content_open_pipefs,
1840 .read = seq_read,
1841 .llseek = seq_lseek,
1842 .release = content_release_pipefs,
1843};
1844
1845static int open_flush_pipefs(struct inode *inode, struct file *filp)
1846{
1847 struct cache_detail *cd = RPC_I(inode)->private;
1848
1849 return open_flush(inode, file: filp, cd);
1850}
1851
1852static int release_flush_pipefs(struct inode *inode, struct file *filp)
1853{
1854 struct cache_detail *cd = RPC_I(inode)->private;
1855
1856 return release_flush(inode, file: filp, cd);
1857}
1858
1859static ssize_t read_flush_pipefs(struct file *filp, char __user *buf,
1860 size_t count, loff_t *ppos)
1861{
1862 struct cache_detail *cd = RPC_I(inode: file_inode(f: filp))->private;
1863
1864 return read_flush(file: filp, buf, count, ppos, cd);
1865}
1866
1867static ssize_t write_flush_pipefs(struct file *filp,
1868 const char __user *buf,
1869 size_t count, loff_t *ppos)
1870{
1871 struct cache_detail *cd = RPC_I(inode: file_inode(f: filp))->private;
1872
1873 return write_flush(file: filp, buf, count, ppos, cd);
1874}
1875
1876const struct file_operations cache_flush_operations_pipefs = {
1877 .open = open_flush_pipefs,
1878 .read = read_flush_pipefs,
1879 .write = write_flush_pipefs,
1880 .release = release_flush_pipefs,
1881};
1882
1883int sunrpc_cache_register_pipefs(struct dentry *parent,
1884 const char *name, umode_t umode,
1885 struct cache_detail *cd)
1886{
1887 struct dentry *dir = rpc_create_cache_dir(parent, name, umode, cd);
1888 if (IS_ERR(ptr: dir))
1889 return PTR_ERR(ptr: dir);
1890 cd->pipefs = dir;
1891 return 0;
1892}
1893EXPORT_SYMBOL_GPL(sunrpc_cache_register_pipefs);
1894
1895void sunrpc_cache_unregister_pipefs(struct cache_detail *cd)
1896{
1897 if (cd->pipefs) {
1898 rpc_remove_cache_dir(cd->pipefs);
1899 cd->pipefs = NULL;
1900 }
1901}
1902EXPORT_SYMBOL_GPL(sunrpc_cache_unregister_pipefs);
1903
1904void sunrpc_cache_unhash(struct cache_detail *cd, struct cache_head *h)
1905{
1906 spin_lock(lock: &cd->hash_lock);
1907 if (!hlist_unhashed(h: &h->cache_list)){
1908 sunrpc_begin_cache_remove_entry(ch: h, cd);
1909 spin_unlock(lock: &cd->hash_lock);
1910 sunrpc_end_cache_remove_entry(ch: h, cd);
1911 } else
1912 spin_unlock(lock: &cd->hash_lock);
1913}
1914EXPORT_SYMBOL_GPL(sunrpc_cache_unhash);
1915