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TOMOYO Linux Cross Reference
Linux/net/sunrpc/cache.c

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  1 /*
  2  * net/sunrpc/cache.c
  3  *
  4  * Generic code for various authentication-related caches
  5  * used by sunrpc clients and servers.
  6  *
  7  * Copyright (C) 2002 Neil Brown <neilb@cse.unsw.edu.au>
  8  *
  9  * Released under terms in GPL version 2.  See COPYING.
 10  *
 11  */
 12 
 13 #include <linux/types.h>
 14 #include <linux/fs.h>
 15 #include <linux/file.h>
 16 #include <linux/slab.h>
 17 #include <linux/signal.h>
 18 #include <linux/sched.h>
 19 #include <linux/kmod.h>
 20 #include <linux/list.h>
 21 #include <linux/module.h>
 22 #include <linux/ctype.h>
 23 #include <asm/uaccess.h>
 24 #include <linux/poll.h>
 25 #include <linux/seq_file.h>
 26 #include <linux/proc_fs.h>
 27 #include <linux/net.h>
 28 #include <linux/workqueue.h>
 29 #include <linux/mutex.h>
 30 #include <linux/pagemap.h>
 31 #include <asm/ioctls.h>
 32 #include <linux/sunrpc/types.h>
 33 #include <linux/sunrpc/cache.h>
 34 #include <linux/sunrpc/stats.h>
 35 #include <linux/sunrpc/rpc_pipe_fs.h>
 36 #include "netns.h"
 37 
 38 #define  RPCDBG_FACILITY RPCDBG_CACHE
 39 
 40 static bool cache_defer_req(struct cache_req *req, struct cache_head *item);
 41 static void cache_revisit_request(struct cache_head *item);
 42 
 43 static void cache_init(struct cache_head *h)
 44 {
 45         time_t now = seconds_since_boot();
 46         h->next = NULL;
 47         h->flags = 0;
 48         kref_init(&h->ref);
 49         h->expiry_time = now + CACHE_NEW_EXPIRY;
 50         h->last_refresh = now;
 51 }
 52 
 53 static inline int cache_is_expired(struct cache_detail *detail, struct cache_head *h)
 54 {
 55         return  (h->expiry_time < seconds_since_boot()) ||
 56                 (detail->flush_time > h->last_refresh);
 57 }
 58 
 59 struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail,
 60                                        struct cache_head *key, int hash)
 61 {
 62         struct cache_head **head,  **hp;
 63         struct cache_head *new = NULL, *freeme = NULL;
 64 
 65         head = &detail->hash_table[hash];
 66 
 67         read_lock(&detail->hash_lock);
 68 
 69         for (hp=head; *hp != NULL ; hp = &(*hp)->next) {
 70                 struct cache_head *tmp = *hp;
 71                 if (detail->match(tmp, key)) {
 72                         if (cache_is_expired(detail, tmp))
 73                                 /* This entry is expired, we will discard it. */
 74                                 break;
 75                         cache_get(tmp);
 76                         read_unlock(&detail->hash_lock);
 77                         return tmp;
 78                 }
 79         }
 80         read_unlock(&detail->hash_lock);
 81         /* Didn't find anything, insert an empty entry */
 82 
 83         new = detail->alloc();
 84         if (!new)
 85                 return NULL;
 86         /* must fully initialise 'new', else
 87          * we might get lose if we need to
 88          * cache_put it soon.
 89          */
 90         cache_init(new);
 91         detail->init(new, key);
 92 
 93         write_lock(&detail->hash_lock);
 94 
 95         /* check if entry appeared while we slept */
 96         for (hp=head; *hp != NULL ; hp = &(*hp)->next) {
 97                 struct cache_head *tmp = *hp;
 98                 if (detail->match(tmp, key)) {
 99                         if (cache_is_expired(detail, tmp)) {
100                                 *hp = tmp->next;
101                                 tmp->next = NULL;
102                                 detail->entries --;
103                                 freeme = tmp;
104                                 break;
105                         }
106                         cache_get(tmp);
107                         write_unlock(&detail->hash_lock);
108                         cache_put(new, detail);
109                         return tmp;
110                 }
111         }
112         new->next = *head;
113         *head = new;
114         detail->entries++;
115         cache_get(new);
116         write_unlock(&detail->hash_lock);
117 
118         if (freeme)
119                 cache_put(freeme, detail);
120         return new;
121 }
122 EXPORT_SYMBOL_GPL(sunrpc_cache_lookup);
123 
124 
125 static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch);
126 
127 static void cache_fresh_locked(struct cache_head *head, time_t expiry)
128 {
129         head->expiry_time = expiry;
130         head->last_refresh = seconds_since_boot();
131         smp_wmb(); /* paired with smp_rmb() in cache_is_valid() */
132         set_bit(CACHE_VALID, &head->flags);
133 }
134 
135 static void cache_fresh_unlocked(struct cache_head *head,
136                                  struct cache_detail *detail)
137 {
138         if (test_and_clear_bit(CACHE_PENDING, &head->flags)) {
139                 cache_revisit_request(head);
140                 cache_dequeue(detail, head);
141         }
142 }
143 
144 struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
145                                        struct cache_head *new, struct cache_head *old, int hash)
146 {
147         /* The 'old' entry is to be replaced by 'new'.
148          * If 'old' is not VALID, we update it directly,
149          * otherwise we need to replace it
150          */
151         struct cache_head **head;
152         struct cache_head *tmp;
153 
154         if (!test_bit(CACHE_VALID, &old->flags)) {
155                 write_lock(&detail->hash_lock);
156                 if (!test_bit(CACHE_VALID, &old->flags)) {
157                         if (test_bit(CACHE_NEGATIVE, &new->flags))
158                                 set_bit(CACHE_NEGATIVE, &old->flags);
159                         else
160                                 detail->update(old, new);
161                         cache_fresh_locked(old, new->expiry_time);
162                         write_unlock(&detail->hash_lock);
163                         cache_fresh_unlocked(old, detail);
164                         return old;
165                 }
166                 write_unlock(&detail->hash_lock);
167         }
168         /* We need to insert a new entry */
169         tmp = detail->alloc();
170         if (!tmp) {
171                 cache_put(old, detail);
172                 return NULL;
173         }
174         cache_init(tmp);
175         detail->init(tmp, old);
176         head = &detail->hash_table[hash];
177 
178         write_lock(&detail->hash_lock);
179         if (test_bit(CACHE_NEGATIVE, &new->flags))
180                 set_bit(CACHE_NEGATIVE, &tmp->flags);
181         else
182                 detail->update(tmp, new);
183         tmp->next = *head;
184         *head = tmp;
185         detail->entries++;
186         cache_get(tmp);
187         cache_fresh_locked(tmp, new->expiry_time);
188         cache_fresh_locked(old, 0);
189         write_unlock(&detail->hash_lock);
190         cache_fresh_unlocked(tmp, detail);
191         cache_fresh_unlocked(old, detail);
192         cache_put(old, detail);
193         return tmp;
194 }
195 EXPORT_SYMBOL_GPL(sunrpc_cache_update);
196 
197 static int cache_make_upcall(struct cache_detail *cd, struct cache_head *h)
198 {
199         if (!cd->cache_upcall)
200                 return -EINVAL;
201         return cd->cache_upcall(cd, h);
202 }
203 
204 static inline int cache_is_valid(struct cache_detail *detail, struct cache_head *h)
205 {
206         if (!test_bit(CACHE_VALID, &h->flags))
207                 return -EAGAIN;
208         else {
209                 /* entry is valid */
210                 if (test_bit(CACHE_NEGATIVE, &h->flags))
211                         return -ENOENT;
212                 else {
213                         /*
214                          * In combination with write barrier in
215                          * sunrpc_cache_update, ensures that anyone
216                          * using the cache entry after this sees the
217                          * updated contents:
218                          */
219                         smp_rmb();
220                         return 0;
221                 }
222         }
223 }
224 
225 static int try_to_negate_entry(struct cache_detail *detail, struct cache_head *h)
226 {
227         int rv;
228 
229         write_lock(&detail->hash_lock);
230         rv = cache_is_valid(detail, h);
231         if (rv != -EAGAIN) {
232                 write_unlock(&detail->hash_lock);
233                 return rv;
234         }
235         set_bit(CACHE_NEGATIVE, &h->flags);
236         cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY);
237         write_unlock(&detail->hash_lock);
238         cache_fresh_unlocked(h, detail);
239         return -ENOENT;
240 }
241 
242 /*
243  * This is the generic cache management routine for all
244  * the authentication caches.
245  * It checks the currency of a cache item and will (later)
246  * initiate an upcall to fill it if needed.
247  *
248  *
249  * Returns 0 if the cache_head can be used, or cache_puts it and returns
250  * -EAGAIN if upcall is pending and request has been queued
251  * -ETIMEDOUT if upcall failed or request could not be queue or
252  *           upcall completed but item is still invalid (implying that
253  *           the cache item has been replaced with a newer one).
254  * -ENOENT if cache entry was negative
255  */
256 int cache_check(struct cache_detail *detail,
257                     struct cache_head *h, struct cache_req *rqstp)
258 {
259         int rv;
260         long refresh_age, age;
261 
262         /* First decide return status as best we can */
263         rv = cache_is_valid(detail, h);
264 
265         /* now see if we want to start an upcall */
266         refresh_age = (h->expiry_time - h->last_refresh);
267         age = seconds_since_boot() - h->last_refresh;
268 
269         if (rqstp == NULL) {
270                 if (rv == -EAGAIN)
271                         rv = -ENOENT;
272         } else if (rv == -EAGAIN || age > refresh_age/2) {
273                 dprintk("RPC:       Want update, refage=%ld, age=%ld\n",
274                                 refresh_age, age);
275                 if (!test_and_set_bit(CACHE_PENDING, &h->flags)) {
276                         switch (cache_make_upcall(detail, h)) {
277                         case -EINVAL:
278                                 clear_bit(CACHE_PENDING, &h->flags);
279                                 cache_revisit_request(h);
280                                 rv = try_to_negate_entry(detail, h);
281                                 break;
282                         case -EAGAIN:
283                                 clear_bit(CACHE_PENDING, &h->flags);
284                                 cache_revisit_request(h);
285                                 break;
286                         }
287                 }
288         }
289 
290         if (rv == -EAGAIN) {
291                 if (!cache_defer_req(rqstp, h)) {
292                         /*
293                          * Request was not deferred; handle it as best
294                          * we can ourselves:
295                          */
296                         rv = cache_is_valid(detail, h);
297                         if (rv == -EAGAIN)
298                                 rv = -ETIMEDOUT;
299                 }
300         }
301         if (rv)
302                 cache_put(h, detail);
303         return rv;
304 }
305 EXPORT_SYMBOL_GPL(cache_check);
306 
307 /*
308  * caches need to be periodically cleaned.
309  * For this we maintain a list of cache_detail and
310  * a current pointer into that list and into the table
311  * for that entry.
312  *
313  * Each time clean_cache is called it finds the next non-empty entry
314  * in the current table and walks the list in that entry
315  * looking for entries that can be removed.
316  *
317  * An entry gets removed if:
318  * - The expiry is before current time
319  * - The last_refresh time is before the flush_time for that cache
320  *
321  * later we might drop old entries with non-NEVER expiry if that table
322  * is getting 'full' for some definition of 'full'
323  *
324  * The question of "how often to scan a table" is an interesting one
325  * and is answered in part by the use of the "nextcheck" field in the
326  * cache_detail.
327  * When a scan of a table begins, the nextcheck field is set to a time
328  * that is well into the future.
329  * While scanning, if an expiry time is found that is earlier than the
330  * current nextcheck time, nextcheck is set to that expiry time.
331  * If the flush_time is ever set to a time earlier than the nextcheck
332  * time, the nextcheck time is then set to that flush_time.
333  *
334  * A table is then only scanned if the current time is at least
335  * the nextcheck time.
336  *
337  */
338 
339 static LIST_HEAD(cache_list);
340 static DEFINE_SPINLOCK(cache_list_lock);
341 static struct cache_detail *current_detail;
342 static int current_index;
343 
344 static void do_cache_clean(struct work_struct *work);
345 static struct delayed_work cache_cleaner;
346 
347 void sunrpc_init_cache_detail(struct cache_detail *cd)
348 {
349         rwlock_init(&cd->hash_lock);
350         INIT_LIST_HEAD(&cd->queue);
351         spin_lock(&cache_list_lock);
352         cd->nextcheck = 0;
353         cd->entries = 0;
354         atomic_set(&cd->readers, 0);
355         cd->last_close = 0;
356         cd->last_warn = -1;
357         list_add(&cd->others, &cache_list);
358         spin_unlock(&cache_list_lock);
359 
360         /* start the cleaning process */
361         schedule_delayed_work(&cache_cleaner, 0);
362 }
363 EXPORT_SYMBOL_GPL(sunrpc_init_cache_detail);
364 
365 void sunrpc_destroy_cache_detail(struct cache_detail *cd)
366 {
367         cache_purge(cd);
368         spin_lock(&cache_list_lock);
369         write_lock(&cd->hash_lock);
370         if (cd->entries || atomic_read(&cd->inuse)) {
371                 write_unlock(&cd->hash_lock);
372                 spin_unlock(&cache_list_lock);
373                 goto out;
374         }
375         if (current_detail == cd)
376                 current_detail = NULL;
377         list_del_init(&cd->others);
378         write_unlock(&cd->hash_lock);
379         spin_unlock(&cache_list_lock);
380         if (list_empty(&cache_list)) {
381                 /* module must be being unloaded so its safe to kill the worker */
382                 cancel_delayed_work_sync(&cache_cleaner);
383         }
384         return;
385 out:
386         printk(KERN_ERR "nfsd: failed to unregister %s cache\n", cd->name);
387 }
388 EXPORT_SYMBOL_GPL(sunrpc_destroy_cache_detail);
389 
390 /* clean cache tries to find something to clean
391  * and cleans it.
392  * It returns 1 if it cleaned something,
393  *            0 if it didn't find anything this time
394  *           -1 if it fell off the end of the list.
395  */
396 static int cache_clean(void)
397 {
398         int rv = 0;
399         struct list_head *next;
400 
401         spin_lock(&cache_list_lock);
402 
403         /* find a suitable table if we don't already have one */
404         while (current_detail == NULL ||
405             current_index >= current_detail->hash_size) {
406                 if (current_detail)
407                         next = current_detail->others.next;
408                 else
409                         next = cache_list.next;
410                 if (next == &cache_list) {
411                         current_detail = NULL;
412                         spin_unlock(&cache_list_lock);
413                         return -1;
414                 }
415                 current_detail = list_entry(next, struct cache_detail, others);
416                 if (current_detail->nextcheck > seconds_since_boot())
417                         current_index = current_detail->hash_size;
418                 else {
419                         current_index = 0;
420                         current_detail->nextcheck = seconds_since_boot()+30*60;
421                 }
422         }
423 
424         /* find a non-empty bucket in the table */
425         while (current_detail &&
426                current_index < current_detail->hash_size &&
427                current_detail->hash_table[current_index] == NULL)
428                 current_index++;
429 
430         /* find a cleanable entry in the bucket and clean it, or set to next bucket */
431 
432         if (current_detail && current_index < current_detail->hash_size) {
433                 struct cache_head *ch, **cp;
434                 struct cache_detail *d;
435 
436                 write_lock(&current_detail->hash_lock);
437 
438                 /* Ok, now to clean this strand */
439 
440                 cp = & current_detail->hash_table[current_index];
441                 for (ch = *cp ; ch ; cp = & ch->next, ch = *cp) {
442                         if (current_detail->nextcheck > ch->expiry_time)
443                                 current_detail->nextcheck = ch->expiry_time+1;
444                         if (!cache_is_expired(current_detail, ch))
445                                 continue;
446 
447                         *cp = ch->next;
448                         ch->next = NULL;
449                         current_detail->entries--;
450                         rv = 1;
451                         break;
452                 }
453 
454                 write_unlock(&current_detail->hash_lock);
455                 d = current_detail;
456                 if (!ch)
457                         current_index ++;
458                 spin_unlock(&cache_list_lock);
459                 if (ch) {
460                         if (test_and_clear_bit(CACHE_PENDING, &ch->flags))
461                                 cache_dequeue(current_detail, ch);
462                         cache_revisit_request(ch);
463                         cache_put(ch, d);
464                 }
465         } else
466                 spin_unlock(&cache_list_lock);
467 
468         return rv;
469 }
470 
471 /*
472  * We want to regularly clean the cache, so we need to schedule some work ...
473  */
474 static void do_cache_clean(struct work_struct *work)
475 {
476         int delay = 5;
477         if (cache_clean() == -1)
478                 delay = round_jiffies_relative(30*HZ);
479 
480         if (list_empty(&cache_list))
481                 delay = 0;
482 
483         if (delay)
484                 schedule_delayed_work(&cache_cleaner, delay);
485 }
486 
487 
488 /*
489  * Clean all caches promptly.  This just calls cache_clean
490  * repeatedly until we are sure that every cache has had a chance to
491  * be fully cleaned
492  */
493 void cache_flush(void)
494 {
495         while (cache_clean() != -1)
496                 cond_resched();
497         while (cache_clean() != -1)
498                 cond_resched();
499 }
500 EXPORT_SYMBOL_GPL(cache_flush);
501 
502 void cache_purge(struct cache_detail *detail)
503 {
504         detail->flush_time = LONG_MAX;
505         detail->nextcheck = seconds_since_boot();
506         cache_flush();
507         detail->flush_time = 1;
508 }
509 EXPORT_SYMBOL_GPL(cache_purge);
510 
511 
512 /*
513  * Deferral and Revisiting of Requests.
514  *
515  * If a cache lookup finds a pending entry, we
516  * need to defer the request and revisit it later.
517  * All deferred requests are stored in a hash table,
518  * indexed by "struct cache_head *".
519  * As it may be wasteful to store a whole request
520  * structure, we allow the request to provide a
521  * deferred form, which must contain a
522  * 'struct cache_deferred_req'
523  * This cache_deferred_req contains a method to allow
524  * it to be revisited when cache info is available
525  */
526 
527 #define DFR_HASHSIZE    (PAGE_SIZE/sizeof(struct list_head))
528 #define DFR_HASH(item)  ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE)
529 
530 #define DFR_MAX 300     /* ??? */
531 
532 static DEFINE_SPINLOCK(cache_defer_lock);
533 static LIST_HEAD(cache_defer_list);
534 static struct hlist_head cache_defer_hash[DFR_HASHSIZE];
535 static int cache_defer_cnt;
536 
537 static void __unhash_deferred_req(struct cache_deferred_req *dreq)
538 {
539         hlist_del_init(&dreq->hash);
540         if (!list_empty(&dreq->recent)) {
541                 list_del_init(&dreq->recent);
542                 cache_defer_cnt--;
543         }
544 }
545 
546 static void __hash_deferred_req(struct cache_deferred_req *dreq, struct cache_head *item)
547 {
548         int hash = DFR_HASH(item);
549 
550         INIT_LIST_HEAD(&dreq->recent);
551         hlist_add_head(&dreq->hash, &cache_defer_hash[hash]);
552 }
553 
554 static void setup_deferral(struct cache_deferred_req *dreq,
555                            struct cache_head *item,
556                            int count_me)
557 {
558 
559         dreq->item = item;
560 
561         spin_lock(&cache_defer_lock);
562 
563         __hash_deferred_req(dreq, item);
564 
565         if (count_me) {
566                 cache_defer_cnt++;
567                 list_add(&dreq->recent, &cache_defer_list);
568         }
569 
570         spin_unlock(&cache_defer_lock);
571 
572 }
573 
574 struct thread_deferred_req {
575         struct cache_deferred_req handle;
576         struct completion completion;
577 };
578 
579 static void cache_restart_thread(struct cache_deferred_req *dreq, int too_many)
580 {
581         struct thread_deferred_req *dr =
582                 container_of(dreq, struct thread_deferred_req, handle);
583         complete(&dr->completion);
584 }
585 
586 static void cache_wait_req(struct cache_req *req, struct cache_head *item)
587 {
588         struct thread_deferred_req sleeper;
589         struct cache_deferred_req *dreq = &sleeper.handle;
590 
591         sleeper.completion = COMPLETION_INITIALIZER_ONSTACK(sleeper.completion);
592         dreq->revisit = cache_restart_thread;
593 
594         setup_deferral(dreq, item, 0);
595 
596         if (!test_bit(CACHE_PENDING, &item->flags) ||
597             wait_for_completion_interruptible_timeout(
598                     &sleeper.completion, req->thread_wait) <= 0) {
599                 /* The completion wasn't completed, so we need
600                  * to clean up
601                  */
602                 spin_lock(&cache_defer_lock);
603                 if (!hlist_unhashed(&sleeper.handle.hash)) {
604                         __unhash_deferred_req(&sleeper.handle);
605                         spin_unlock(&cache_defer_lock);
606                 } else {
607                         /* cache_revisit_request already removed
608                          * this from the hash table, but hasn't
609                          * called ->revisit yet.  It will very soon
610                          * and we need to wait for it.
611                          */
612                         spin_unlock(&cache_defer_lock);
613                         wait_for_completion(&sleeper.completion);
614                 }
615         }
616 }
617 
618 static void cache_limit_defers(void)
619 {
620         /* Make sure we haven't exceed the limit of allowed deferred
621          * requests.
622          */
623         struct cache_deferred_req *discard = NULL;
624 
625         if (cache_defer_cnt <= DFR_MAX)
626                 return;
627 
628         spin_lock(&cache_defer_lock);
629 
630         /* Consider removing either the first or the last */
631         if (cache_defer_cnt > DFR_MAX) {
632                 if (net_random() & 1)
633                         discard = list_entry(cache_defer_list.next,
634                                              struct cache_deferred_req, recent);
635                 else
636                         discard = list_entry(cache_defer_list.prev,
637                                              struct cache_deferred_req, recent);
638                 __unhash_deferred_req(discard);
639         }
640         spin_unlock(&cache_defer_lock);
641         if (discard)
642                 discard->revisit(discard, 1);
643 }
644 
645 /* Return true if and only if a deferred request is queued. */
646 static bool cache_defer_req(struct cache_req *req, struct cache_head *item)
647 {
648         struct cache_deferred_req *dreq;
649 
650         if (req->thread_wait) {
651                 cache_wait_req(req, item);
652                 if (!test_bit(CACHE_PENDING, &item->flags))
653                         return false;
654         }
655         dreq = req->defer(req);
656         if (dreq == NULL)
657                 return false;
658         setup_deferral(dreq, item, 1);
659         if (!test_bit(CACHE_PENDING, &item->flags))
660                 /* Bit could have been cleared before we managed to
661                  * set up the deferral, so need to revisit just in case
662                  */
663                 cache_revisit_request(item);
664 
665         cache_limit_defers();
666         return true;
667 }
668 
669 static void cache_revisit_request(struct cache_head *item)
670 {
671         struct cache_deferred_req *dreq;
672         struct list_head pending;
673         struct hlist_node *lp, *tmp;
674         int hash = DFR_HASH(item);
675 
676         INIT_LIST_HEAD(&pending);
677         spin_lock(&cache_defer_lock);
678 
679         hlist_for_each_entry_safe(dreq, lp, tmp, &cache_defer_hash[hash], hash)
680                 if (dreq->item == item) {
681                         __unhash_deferred_req(dreq);
682                         list_add(&dreq->recent, &pending);
683                 }
684 
685         spin_unlock(&cache_defer_lock);
686 
687         while (!list_empty(&pending)) {
688                 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
689                 list_del_init(&dreq->recent);
690                 dreq->revisit(dreq, 0);
691         }
692 }
693 
694 void cache_clean_deferred(void *owner)
695 {
696         struct cache_deferred_req *dreq, *tmp;
697         struct list_head pending;
698 
699 
700         INIT_LIST_HEAD(&pending);
701         spin_lock(&cache_defer_lock);
702 
703         list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) {
704                 if (dreq->owner == owner) {
705                         __unhash_deferred_req(dreq);
706                         list_add(&dreq->recent, &pending);
707                 }
708         }
709         spin_unlock(&cache_defer_lock);
710 
711         while (!list_empty(&pending)) {
712                 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
713                 list_del_init(&dreq->recent);
714                 dreq->revisit(dreq, 1);
715         }
716 }
717 
718 /*
719  * communicate with user-space
720  *
721  * We have a magic /proc file - /proc/sunrpc/<cachename>/channel.
722  * On read, you get a full request, or block.
723  * On write, an update request is processed.
724  * Poll works if anything to read, and always allows write.
725  *
726  * Implemented by linked list of requests.  Each open file has
727  * a ->private that also exists in this list.  New requests are added
728  * to the end and may wakeup and preceding readers.
729  * New readers are added to the head.  If, on read, an item is found with
730  * CACHE_UPCALLING clear, we free it from the list.
731  *
732  */
733 
734 static DEFINE_SPINLOCK(queue_lock);
735 static DEFINE_MUTEX(queue_io_mutex);
736 
737 struct cache_queue {
738         struct list_head        list;
739         int                     reader; /* if 0, then request */
740 };
741 struct cache_request {
742         struct cache_queue      q;
743         struct cache_head       *item;
744         char                    * buf;
745         int                     len;
746         int                     readers;
747 };
748 struct cache_reader {
749         struct cache_queue      q;
750         int                     offset; /* if non-0, we have a refcnt on next request */
751 };
752 
753 static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
754                           loff_t *ppos, struct cache_detail *cd)
755 {
756         struct cache_reader *rp = filp->private_data;
757         struct cache_request *rq;
758         struct inode *inode = filp->f_path.dentry->d_inode;
759         int err;
760 
761         if (count == 0)
762                 return 0;
763 
764         mutex_lock(&inode->i_mutex); /* protect against multiple concurrent
765                               * readers on this file */
766  again:
767         spin_lock(&queue_lock);
768         /* need to find next request */
769         while (rp->q.list.next != &cd->queue &&
770                list_entry(rp->q.list.next, struct cache_queue, list)
771                ->reader) {
772                 struct list_head *next = rp->q.list.next;
773                 list_move(&rp->q.list, next);
774         }
775         if (rp->q.list.next == &cd->queue) {
776                 spin_unlock(&queue_lock);
777                 mutex_unlock(&inode->i_mutex);
778                 BUG_ON(rp->offset);
779                 return 0;
780         }
781         rq = container_of(rp->q.list.next, struct cache_request, q.list);
782         BUG_ON(rq->q.reader);
783         if (rp->offset == 0)
784                 rq->readers++;
785         spin_unlock(&queue_lock);
786 
787         if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
788                 err = -EAGAIN;
789                 spin_lock(&queue_lock);
790                 list_move(&rp->q.list, &rq->q.list);
791                 spin_unlock(&queue_lock);
792         } else {
793                 if (rp->offset + count > rq->len)
794                         count = rq->len - rp->offset;
795                 err = -EFAULT;
796                 if (copy_to_user(buf, rq->buf + rp->offset, count))
797                         goto out;
798                 rp->offset += count;
799                 if (rp->offset >= rq->len) {
800                         rp->offset = 0;
801                         spin_lock(&queue_lock);
802                         list_move(&rp->q.list, &rq->q.list);
803                         spin_unlock(&queue_lock);
804                 }
805                 err = 0;
806         }
807  out:
808         if (rp->offset == 0) {
809                 /* need to release rq */
810                 spin_lock(&queue_lock);
811                 rq->readers--;
812                 if (rq->readers == 0 &&
813                     !test_bit(CACHE_PENDING, &rq->item->flags)) {
814                         list_del(&rq->q.list);
815                         spin_unlock(&queue_lock);
816                         cache_put(rq->item, cd);
817                         kfree(rq->buf);
818                         kfree(rq);
819                 } else
820                         spin_unlock(&queue_lock);
821         }
822         if (err == -EAGAIN)
823                 goto again;
824         mutex_unlock(&inode->i_mutex);
825         return err ? err :  count;
826 }
827 
828 static ssize_t cache_do_downcall(char *kaddr, const char __user *buf,
829                                  size_t count, struct cache_detail *cd)
830 {
831         ssize_t ret;
832 
833         if (count == 0)
834                 return -EINVAL;
835         if (copy_from_user(kaddr, buf, count))
836                 return -EFAULT;
837         kaddr[count] = '\0';
838         ret = cd->cache_parse(cd, kaddr, count);
839         if (!ret)
840                 ret = count;
841         return ret;
842 }
843 
844 static ssize_t cache_slow_downcall(const char __user *buf,
845                                    size_t count, struct cache_detail *cd)
846 {
847         static char write_buf[8192]; /* protected by queue_io_mutex */
848         ssize_t ret = -EINVAL;
849 
850         if (count >= sizeof(write_buf))
851                 goto out;
852         mutex_lock(&queue_io_mutex);
853         ret = cache_do_downcall(write_buf, buf, count, cd);
854         mutex_unlock(&queue_io_mutex);
855 out:
856         return ret;
857 }
858 
859 static ssize_t cache_downcall(struct address_space *mapping,
860                               const char __user *buf,
861                               size_t count, struct cache_detail *cd)
862 {
863         struct page *page;
864         char *kaddr;
865         ssize_t ret = -ENOMEM;
866 
867         if (count >= PAGE_CACHE_SIZE)
868                 goto out_slow;
869 
870         page = find_or_create_page(mapping, 0, GFP_KERNEL);
871         if (!page)
872                 goto out_slow;
873 
874         kaddr = kmap(page);
875         ret = cache_do_downcall(kaddr, buf, count, cd);
876         kunmap(page);
877         unlock_page(page);
878         page_cache_release(page);
879         return ret;
880 out_slow:
881         return cache_slow_downcall(buf, count, cd);
882 }
883 
884 static ssize_t cache_write(struct file *filp, const char __user *buf,
885                            size_t count, loff_t *ppos,
886                            struct cache_detail *cd)
887 {
888         struct address_space *mapping = filp->f_mapping;
889         struct inode *inode = filp->f_path.dentry->d_inode;
890         ssize_t ret = -EINVAL;
891 
892         if (!cd->cache_parse)
893                 goto out;
894 
895         mutex_lock(&inode->i_mutex);
896         ret = cache_downcall(mapping, buf, count, cd);
897         mutex_unlock(&inode->i_mutex);
898 out:
899         return ret;
900 }
901 
902 static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
903 
904 static unsigned int cache_poll(struct file *filp, poll_table *wait,
905                                struct cache_detail *cd)
906 {
907         unsigned int mask;
908         struct cache_reader *rp = filp->private_data;
909         struct cache_queue *cq;
910 
911         poll_wait(filp, &queue_wait, wait);
912 
913         /* alway allow write */
914         mask = POLL_OUT | POLLWRNORM;
915 
916         if (!rp)
917                 return mask;
918 
919         spin_lock(&queue_lock);
920 
921         for (cq= &rp->q; &cq->list != &cd->queue;
922              cq = list_entry(cq->list.next, struct cache_queue, list))
923                 if (!cq->reader) {
924                         mask |= POLLIN | POLLRDNORM;
925                         break;
926                 }
927         spin_unlock(&queue_lock);
928         return mask;
929 }
930 
931 static int cache_ioctl(struct inode *ino, struct file *filp,
932                        unsigned int cmd, unsigned long arg,
933                        struct cache_detail *cd)
934 {
935         int len = 0;
936         struct cache_reader *rp = filp->private_data;
937         struct cache_queue *cq;
938 
939         if (cmd != FIONREAD || !rp)
940                 return -EINVAL;
941 
942         spin_lock(&queue_lock);
943 
944         /* only find the length remaining in current request,
945          * or the length of the next request
946          */
947         for (cq= &rp->q; &cq->list != &cd->queue;
948              cq = list_entry(cq->list.next, struct cache_queue, list))
949                 if (!cq->reader) {
950                         struct cache_request *cr =
951                                 container_of(cq, struct cache_request, q);
952                         len = cr->len - rp->offset;
953                         break;
954                 }
955         spin_unlock(&queue_lock);
956 
957         return put_user(len, (int __user *)arg);
958 }
959 
960 static int cache_open(struct inode *inode, struct file *filp,
961                       struct cache_detail *cd)
962 {
963         struct cache_reader *rp = NULL;
964 
965         if (!cd || !try_module_get(cd->owner))
966                 return -EACCES;
967         nonseekable_open(inode, filp);
968         if (filp->f_mode & FMODE_READ) {
969                 rp = kmalloc(sizeof(*rp), GFP_KERNEL);
970                 if (!rp)
971                         return -ENOMEM;
972                 rp->offset = 0;
973                 rp->q.reader = 1;
974                 atomic_inc(&cd->readers);
975                 spin_lock(&queue_lock);
976                 list_add(&rp->q.list, &cd->queue);
977                 spin_unlock(&queue_lock);
978         }
979         filp->private_data = rp;
980         return 0;
981 }
982 
983 static int cache_release(struct inode *inode, struct file *filp,
984                          struct cache_detail *cd)
985 {
986         struct cache_reader *rp = filp->private_data;
987 
988         if (rp) {
989                 spin_lock(&queue_lock);
990                 if (rp->offset) {
991                         struct cache_queue *cq;
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                                         container_of(cq, struct cache_request, q)
996                                                 ->readers--;
997                                         break;
998                                 }
999                         rp->offset = 0;
1000                 }
1001                 list_del(&rp->q.list);
1002                 spin_unlock(&queue_lock);
1003 
1004                 filp->private_data = NULL;
1005                 kfree(rp);
1006 
1007                 cd->last_close = seconds_since_boot();
1008                 atomic_dec(&cd->readers);
1009         }
1010         module_put(cd->owner);
1011         return 0;
1012 }
1013 
1014 
1015 
1016 static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch)
1017 {
1018         struct cache_queue *cq;
1019         spin_lock(&queue_lock);
1020         list_for_each_entry(cq, &detail->queue, list)
1021                 if (!cq->reader) {
1022                         struct cache_request *cr = container_of(cq, struct cache_request, q);
1023                         if (cr->item != ch)
1024                                 continue;
1025                         if (cr->readers != 0)
1026                                 continue;
1027                         list_del(&cr->q.list);
1028                         spin_unlock(&queue_lock);
1029                         cache_put(cr->item, detail);
1030                         kfree(cr->buf);
1031                         kfree(cr);
1032                         return;
1033                 }
1034         spin_unlock(&queue_lock);
1035 }
1036 
1037 /*
1038  * Support routines for text-based upcalls.
1039  * Fields are separated by spaces.
1040  * Fields are either mangled to quote space tab newline slosh with slosh
1041  * or a hexified with a leading \x
1042  * Record is terminated with newline.
1043  *
1044  */
1045 
1046 void qword_add(char **bpp, int *lp, char *str)
1047 {
1048         char *bp = *bpp;
1049         int len = *lp;
1050         char c;
1051 
1052         if (len < 0) return;
1053 
1054         while ((c=*str++) && len)
1055                 switch(c) {
1056                 case ' ':
1057                 case '\t':
1058                 case '\n':
1059                 case '\\':
1060                         if (len >= 4) {
1061                                 *bp++ = '\\';
1062                                 *bp++ = '' + ((c & 0300)>>6);
1063                                 *bp++ = '' + ((c & 0070)>>3);
1064                                 *bp++ = '' + ((c & 0007)>>0);
1065                         }
1066                         len -= 4;
1067                         break;
1068                 default:
1069                         *bp++ = c;
1070                         len--;
1071                 }
1072         if (c || len <1) len = -1;
1073         else {
1074                 *bp++ = ' ';
1075                 len--;
1076         }
1077         *bpp = bp;
1078         *lp = len;
1079 }
1080 EXPORT_SYMBOL_GPL(qword_add);
1081 
1082 void qword_addhex(char **bpp, int *lp, char *buf, int blen)
1083 {
1084         char *bp = *bpp;
1085         int len = *lp;
1086 
1087         if (len < 0) return;
1088 
1089         if (len > 2) {
1090                 *bp++ = '\\';
1091                 *bp++ = 'x';
1092                 len -= 2;
1093                 while (blen && len >= 2) {
1094                         unsigned char c = *buf++;
1095                         *bp++ = '' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1);
1096                         *bp++ = '' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1);
1097                         len -= 2;
1098                         blen--;
1099                 }
1100         }
1101         if (blen || len<1) len = -1;
1102         else {
1103                 *bp++ = ' ';
1104                 len--;
1105         }
1106         *bpp = bp;
1107         *lp = len;
1108 }
1109 EXPORT_SYMBOL_GPL(qword_addhex);
1110 
1111 static void warn_no_listener(struct cache_detail *detail)
1112 {
1113         if (detail->last_warn != detail->last_close) {
1114                 detail->last_warn = detail->last_close;
1115                 if (detail->warn_no_listener)
1116                         detail->warn_no_listener(detail, detail->last_close != 0);
1117         }
1118 }
1119 
1120 static bool cache_listeners_exist(struct cache_detail *detail)
1121 {
1122         if (atomic_read(&detail->readers))
1123                 return true;
1124         if (detail->last_close == 0)
1125                 /* This cache was never opened */
1126                 return false;
1127         if (detail->last_close < seconds_since_boot() - 30)
1128                 /*
1129                  * We allow for the possibility that someone might
1130                  * restart a userspace daemon without restarting the
1131                  * server; but after 30 seconds, we give up.
1132                  */
1133                  return false;
1134         return true;
1135 }
1136 
1137 /*
1138  * register an upcall request to user-space and queue it up for read() by the
1139  * upcall daemon.
1140  *
1141  * Each request is at most one page long.
1142  */
1143 int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h,
1144                 void (*cache_request)(struct cache_detail *,
1145                                       struct cache_head *,
1146                                       char **,
1147                                       int *))
1148 {
1149 
1150         char *buf;
1151         struct cache_request *crq;
1152         char *bp;
1153         int len;
1154 
1155         if (!cache_listeners_exist(detail)) {
1156                 warn_no_listener(detail);
1157                 return -EINVAL;
1158         }
1159 
1160         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1161         if (!buf)
1162                 return -EAGAIN;
1163 
1164         crq = kmalloc(sizeof (*crq), GFP_KERNEL);
1165         if (!crq) {
1166                 kfree(buf);
1167                 return -EAGAIN;
1168         }
1169 
1170         bp = buf; len = PAGE_SIZE;
1171 
1172         cache_request(detail, h, &bp, &len);
1173 
1174         if (len < 0) {
1175                 kfree(buf);
1176                 kfree(crq);
1177                 return -EAGAIN;
1178         }
1179         crq->q.reader = 0;
1180         crq->item = cache_get(h);
1181         crq->buf = buf;
1182         crq->len = PAGE_SIZE - len;
1183         crq->readers = 0;
1184         spin_lock(&queue_lock);
1185         list_add_tail(&crq->q.list, &detail->queue);
1186         spin_unlock(&queue_lock);
1187         wake_up(&queue_wait);
1188         return 0;
1189 }
1190 EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall);
1191 
1192 /*
1193  * parse a message from user-space and pass it
1194  * to an appropriate cache
1195  * Messages are, like requests, separated into fields by
1196  * spaces and dequotes as \xHEXSTRING or embedded \nnn octal
1197  *
1198  * Message is
1199  *   reply cachename expiry key ... content....
1200  *
1201  * key and content are both parsed by cache
1202  */
1203 
1204 #define isodigit(c) (isdigit(c) && c <= '7')
1205 int qword_get(char **bpp, char *dest, int bufsize)
1206 {
1207         /* return bytes copied, or -1 on error */
1208         char *bp = *bpp;
1209         int len = 0;
1210 
1211         while (*bp == ' ') bp++;
1212 
1213         if (bp[0] == '\\' && bp[1] == 'x') {
1214                 /* HEX STRING */
1215                 bp += 2;
1216                 while (len < bufsize) {
1217                         int h, l;
1218 
1219                         h = hex_to_bin(bp[0]);
1220                         if (h < 0)
1221                                 break;
1222 
1223                         l = hex_to_bin(bp[1]);
1224                         if (l < 0)
1225                                 break;
1226 
1227                         *dest++ = (h << 4) | l;
1228                         bp += 2;
1229                         len++;
1230                 }
1231         } else {
1232                 /* text with \nnn octal quoting */
1233                 while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) {
1234                         if (*bp == '\\' &&
1235                             isodigit(bp[1]) && (bp[1] <= '3') &&
1236                             isodigit(bp[2]) &&
1237                             isodigit(bp[3])) {
1238                                 int byte = (*++bp -'');
1239                                 bp++;
1240                                 byte = (byte << 3) | (*bp++ - '');
1241                                 byte = (byte << 3) | (*bp++ - '');
1242                                 *dest++ = byte;
1243                                 len++;
1244                         } else {
1245                                 *dest++ = *bp++;
1246                                 len++;
1247                         }
1248                 }
1249         }
1250 
1251         if (*bp != ' ' && *bp != '\n' && *bp != '\0')
1252                 return -1;
1253         while (*bp == ' ') bp++;
1254         *bpp = bp;
1255         *dest = '\0';
1256         return len;
1257 }
1258 EXPORT_SYMBOL_GPL(qword_get);
1259 
1260 
1261 /*
1262  * support /proc/sunrpc/cache/$CACHENAME/content
1263  * as a seqfile.
1264  * We call ->cache_show passing NULL for the item to
1265  * get a header, then pass each real item in the cache
1266  */
1267 
1268 struct handle {
1269         struct cache_detail *cd;
1270 };
1271 
1272 static void *c_start(struct seq_file *m, loff_t *pos)
1273         __acquires(cd->hash_lock)
1274 {
1275         loff_t n = *pos;
1276         unsigned int hash, entry;
1277         struct cache_head *ch;
1278         struct cache_detail *cd = ((struct handle*)m->private)->cd;
1279 
1280 
1281         read_lock(&cd->hash_lock);
1282         if (!n--)
1283                 return SEQ_START_TOKEN;
1284         hash = n >> 32;
1285         entry = n & ((1LL<<32) - 1);
1286 
1287         for (ch=cd->hash_table[hash]; ch; ch=ch->next)
1288                 if (!entry--)
1289                         return ch;
1290         n &= ~((1LL<<32) - 1);
1291         do {
1292                 hash++;
1293                 n += 1LL<<32;
1294         } while(hash < cd->hash_size &&
1295                 cd->hash_table[hash]==NULL);
1296         if (hash >= cd->hash_size)
1297                 return NULL;
1298         *pos = n+1;
1299         return cd->hash_table[hash];
1300 }
1301 
1302 static void *c_next(struct seq_file *m, void *p, loff_t *pos)
1303 {
1304         struct cache_head *ch = p;
1305         int hash = (*pos >> 32);
1306         struct cache_detail *cd = ((struct handle*)m->private)->cd;
1307 
1308         if (p == SEQ_START_TOKEN)
1309                 hash = 0;
1310         else if (ch->next == NULL) {
1311                 hash++;
1312                 *pos += 1LL<<32;
1313         } else {
1314                 ++*pos;
1315                 return ch->next;
1316         }
1317         *pos &= ~((1LL<<32) - 1);
1318         while (hash < cd->hash_size &&
1319                cd->hash_table[hash] == NULL) {
1320                 hash++;
1321                 *pos += 1LL<<32;
1322         }
1323         if (hash >= cd->hash_size)
1324                 return NULL;
1325         ++*pos;
1326         return cd->hash_table[hash];
1327 }
1328 
1329 static void c_stop(struct seq_file *m, void *p)
1330         __releases(cd->hash_lock)
1331 {
1332         struct cache_detail *cd = ((struct handle*)m->private)->cd;
1333         read_unlock(&cd->hash_lock);
1334 }
1335 
1336 static int c_show(struct seq_file *m, void *p)
1337 {
1338         struct cache_head *cp = p;
1339         struct cache_detail *cd = ((struct handle*)m->private)->cd;
1340 
1341         if (p == SEQ_START_TOKEN)
1342                 return cd->cache_show(m, cd, NULL);
1343 
1344         ifdebug(CACHE)
1345                 seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n",
1346                            convert_to_wallclock(cp->expiry_time),
1347                            atomic_read(&cp->ref.refcount), cp->flags);
1348         cache_get(cp);
1349         if (cache_check(cd, cp, NULL))
1350                 /* cache_check does a cache_put on failure */
1351                 seq_printf(m, "# ");
1352         else {
1353                 if (cache_is_expired(cd, cp))
1354                         seq_printf(m, "# ");
1355                 cache_put(cp, cd);
1356         }
1357 
1358         return cd->cache_show(m, cd, cp);
1359 }
1360 
1361 static const struct seq_operations cache_content_op = {
1362         .start  = c_start,
1363         .next   = c_next,
1364         .stop   = c_stop,
1365         .show   = c_show,
1366 };
1367 
1368 static int content_open(struct inode *inode, struct file *file,
1369                         struct cache_detail *cd)
1370 {
1371         struct handle *han;
1372 
1373         if (!cd || !try_module_get(cd->owner))
1374                 return -EACCES;
1375         han = __seq_open_private(file, &cache_content_op, sizeof(*han));
1376         if (han == NULL) {
1377                 module_put(cd->owner);
1378                 return -ENOMEM;
1379         }
1380 
1381         han->cd = cd;
1382         return 0;
1383 }
1384 
1385 static int content_release(struct inode *inode, struct file *file,
1386                 struct cache_detail *cd)
1387 {
1388         int ret = seq_release_private(inode, file);
1389         module_put(cd->owner);
1390         return ret;
1391 }
1392 
1393 static int open_flush(struct inode *inode, struct file *file,
1394                         struct cache_detail *cd)
1395 {
1396         if (!cd || !try_module_get(cd->owner))
1397                 return -EACCES;
1398         return nonseekable_open(inode, file);
1399 }
1400 
1401 static int release_flush(struct inode *inode, struct file *file,
1402                         struct cache_detail *cd)
1403 {
1404         module_put(cd->owner);
1405         return 0;
1406 }
1407 
1408 static ssize_t read_flush(struct file *file, char __user *buf,
1409                           size_t count, loff_t *ppos,
1410                           struct cache_detail *cd)
1411 {
1412         char tbuf[22];
1413         unsigned long p = *ppos;
1414         size_t len;
1415 
1416         snprintf(tbuf, sizeof(tbuf), "%lu\n", convert_to_wallclock(cd->flush_time));
1417         len = strlen(tbuf);
1418         if (p >= len)
1419                 return 0;
1420         len -= p;
1421         if (len > count)
1422                 len = count;
1423         if (copy_to_user(buf, (void*)(tbuf+p), len))
1424                 return -EFAULT;
1425         *ppos += len;
1426         return len;
1427 }
1428 
1429 static ssize_t write_flush(struct file *file, const char __user *buf,
1430                            size_t count, loff_t *ppos,
1431                            struct cache_detail *cd)
1432 {
1433         char tbuf[20];
1434         char *bp, *ep;
1435 
1436         if (*ppos || count > sizeof(tbuf)-1)
1437                 return -EINVAL;
1438         if (copy_from_user(tbuf, buf, count))
1439                 return -EFAULT;
1440         tbuf[count] = 0;
1441         simple_strtoul(tbuf, &ep, 0);
1442         if (*ep && *ep != '\n')
1443                 return -EINVAL;
1444 
1445         bp = tbuf;
1446         cd->flush_time = get_expiry(&bp);
1447         cd->nextcheck = seconds_since_boot();
1448         cache_flush();
1449 
1450         *ppos += count;
1451         return count;
1452 }
1453 
1454 static ssize_t cache_read_procfs(struct file *filp, char __user *buf,
1455                                  size_t count, loff_t *ppos)
1456 {
1457         struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
1458 
1459         return cache_read(filp, buf, count, ppos, cd);
1460 }
1461 
1462 static ssize_t cache_write_procfs(struct file *filp, const char __user *buf,
1463                                   size_t count, loff_t *ppos)
1464 {
1465         struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
1466 
1467         return cache_write(filp, buf, count, ppos, cd);
1468 }
1469 
1470 static unsigned int cache_poll_procfs(struct file *filp, poll_table *wait)
1471 {
1472         struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
1473 
1474         return cache_poll(filp, wait, cd);
1475 }
1476 
1477 static long cache_ioctl_procfs(struct file *filp,
1478                                unsigned int cmd, unsigned long arg)
1479 {
1480         struct inode *inode = filp->f_path.dentry->d_inode;
1481         struct cache_detail *cd = PDE(inode)->data;
1482 
1483         return cache_ioctl(inode, filp, cmd, arg, cd);
1484 }
1485 
1486 static int cache_open_procfs(struct inode *inode, struct file *filp)
1487 {
1488         struct cache_detail *cd = PDE(inode)->data;
1489 
1490         return cache_open(inode, filp, cd);
1491 }
1492 
1493 static int cache_release_procfs(struct inode *inode, struct file *filp)
1494 {
1495         struct cache_detail *cd = PDE(inode)->data;
1496 
1497         return cache_release(inode, filp, cd);
1498 }
1499 
1500 static const struct file_operations cache_file_operations_procfs = {
1501         .owner          = THIS_MODULE,
1502         .llseek         = no_llseek,
1503         .read           = cache_read_procfs,
1504         .write          = cache_write_procfs,
1505         .poll           = cache_poll_procfs,
1506         .unlocked_ioctl = cache_ioctl_procfs, /* for FIONREAD */
1507         .open           = cache_open_procfs,
1508         .release        = cache_release_procfs,
1509 };
1510 
1511 static int content_open_procfs(struct inode *inode, struct file *filp)
1512 {
1513         struct cache_detail *cd = PDE(inode)->data;
1514 
1515         return content_open(inode, filp, cd);
1516 }
1517 
1518 static int content_release_procfs(struct inode *inode, struct file *filp)
1519 {
1520         struct cache_detail *cd = PDE(inode)->data;
1521 
1522         return content_release(inode, filp, cd);
1523 }
1524 
1525 static const struct file_operations content_file_operations_procfs = {
1526         .open           = content_open_procfs,
1527         .read           = seq_read,
1528         .llseek         = seq_lseek,
1529         .release        = content_release_procfs,
1530 };
1531 
1532 static int open_flush_procfs(struct inode *inode, struct file *filp)
1533 {
1534         struct cache_detail *cd = PDE(inode)->data;
1535 
1536         return open_flush(inode, filp, cd);
1537 }
1538 
1539 static int release_flush_procfs(struct inode *inode, struct file *filp)
1540 {
1541         struct cache_detail *cd = PDE(inode)->data;
1542 
1543         return release_flush(inode, filp, cd);
1544 }
1545 
1546 static ssize_t read_flush_procfs(struct file *filp, char __user *buf,
1547                             size_t count, loff_t *ppos)
1548 {
1549         struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
1550 
1551         return read_flush(filp, buf, count, ppos, cd);
1552 }
1553 
1554 static ssize_t write_flush_procfs(struct file *filp,
1555                                   const char __user *buf,
1556                                   size_t count, loff_t *ppos)
1557 {
1558         struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
1559 
1560         return write_flush(filp, buf, count, ppos, cd);
1561 }
1562 
1563 static const struct file_operations cache_flush_operations_procfs = {
1564         .open           = open_flush_procfs,
1565         .read           = read_flush_procfs,
1566         .write          = write_flush_procfs,
1567         .release        = release_flush_procfs,
1568         .llseek         = no_llseek,
1569 };
1570 
1571 static void remove_cache_proc_entries(struct cache_detail *cd, struct net *net)
1572 {
1573         struct sunrpc_net *sn;
1574 
1575         if (cd->u.procfs.proc_ent == NULL)
1576                 return;
1577         if (cd->u.procfs.flush_ent)
1578                 remove_proc_entry("flush", cd->u.procfs.proc_ent);
1579         if (cd->u.procfs.channel_ent)
1580                 remove_proc_entry("channel", cd->u.procfs.proc_ent);
1581         if (cd->u.procfs.content_ent)
1582                 remove_proc_entry("content", cd->u.procfs.proc_ent);
1583         cd->u.procfs.proc_ent = NULL;
1584         sn = net_generic(net, sunrpc_net_id);
1585         remove_proc_entry(cd->name, sn->proc_net_rpc);
1586 }
1587 
1588 #ifdef CONFIG_PROC_FS
1589 static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1590 {
1591         struct proc_dir_entry *p;
1592         struct sunrpc_net *sn;
1593 
1594         sn = net_generic(net, sunrpc_net_id);
1595         cd->u.procfs.proc_ent = proc_mkdir(cd->name, sn->proc_net_rpc);
1596         if (cd->u.procfs.proc_ent == NULL)
1597                 goto out_nomem;
1598         cd->u.procfs.channel_ent = NULL;
1599         cd->u.procfs.content_ent = NULL;
1600 
1601         p = proc_create_data("flush", S_IFREG|S_IRUSR|S_IWUSR,
1602                              cd->u.procfs.proc_ent,
1603                              &cache_flush_operations_procfs, cd);
1604         cd->u.procfs.flush_ent = p;
1605         if (p == NULL)
1606                 goto out_nomem;
1607 
1608         if (cd->cache_upcall || cd->cache_parse) {
1609                 p = proc_create_data("channel", S_IFREG|S_IRUSR|S_IWUSR,
1610                                      cd->u.procfs.proc_ent,
1611                                      &cache_file_operations_procfs, cd);
1612                 cd->u.procfs.channel_ent = p;
1613                 if (p == NULL)
1614                         goto out_nomem;
1615         }
1616         if (cd->cache_show) {
1617                 p = proc_create_data("content", S_IFREG|S_IRUSR|S_IWUSR,
1618                                 cd->u.procfs.proc_ent,
1619                                 &content_file_operations_procfs, cd);
1620                 cd->u.procfs.content_ent = p;
1621                 if (p == NULL)
1622                         goto out_nomem;
1623         }
1624         return 0;
1625 out_nomem:
1626         remove_cache_proc_entries(cd, net);
1627         return -ENOMEM;
1628 }
1629 #else /* CONFIG_PROC_FS */
1630 static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1631 {
1632         return 0;
1633 }
1634 #endif
1635 
1636 void __init cache_initialize(void)
1637 {
1638         INIT_DELAYED_WORK_DEFERRABLE(&cache_cleaner, do_cache_clean);
1639 }
1640 
1641 int cache_register_net(struct cache_detail *cd, struct net *net)
1642 {
1643         int ret;
1644 
1645         sunrpc_init_cache_detail(cd);
1646         ret = create_cache_proc_entries(cd, net);
1647         if (ret)
1648                 sunrpc_destroy_cache_detail(cd);
1649         return ret;
1650 }
1651 EXPORT_SYMBOL_GPL(cache_register_net);
1652 
1653 void cache_unregister_net(struct cache_detail *cd, struct net *net)
1654 {
1655         remove_cache_proc_entries(cd, net);
1656         sunrpc_destroy_cache_detail(cd);
1657 }
1658 EXPORT_SYMBOL_GPL(cache_unregister_net);
1659 
1660 struct cache_detail *cache_create_net(struct cache_detail *tmpl, struct net *net)
1661 {
1662         struct cache_detail *cd;
1663 
1664         cd = kmemdup(tmpl, sizeof(struct cache_detail), GFP_KERNEL);
1665         if (cd == NULL)
1666                 return ERR_PTR(-ENOMEM);
1667 
1668         cd->hash_table = kzalloc(cd->hash_size * sizeof(struct cache_head *),
1669                                  GFP_KERNEL);
1670         if (cd->hash_table == NULL) {
1671                 kfree(cd);
1672                 return ERR_PTR(-ENOMEM);
1673         }
1674         cd->net = net;
1675         return cd;
1676 }
1677 EXPORT_SYMBOL_GPL(cache_create_net);
1678 
1679 void cache_destroy_net(struct cache_detail *cd, struct net *net)
1680 {
1681         kfree(cd->hash_table);
1682         kfree(cd);
1683 }
1684 EXPORT_SYMBOL_GPL(cache_destroy_net);
1685 
1686 static ssize_t cache_read_pipefs(struct file *filp, char __user *buf,
1687                                  size_t count, loff_t *ppos)
1688 {
1689         struct cache_detail *cd = RPC_I(filp->f_path.dentry->d_inode)->private;
1690 
1691         return cache_read(filp, buf, count, ppos, cd);
1692 }
1693 
1694 static ssize_t cache_write_pipefs(struct file *filp, const char __user *buf,
1695                                   size_t count, loff_t *ppos)
1696 {
1697         struct cache_detail *cd = RPC_I(filp->f_path.dentry->d_inode)->private;
1698 
1699         return cache_write(filp, buf, count, ppos, cd);
1700 }
1701 
1702 static unsigned int cache_poll_pipefs(struct file *filp, poll_table *wait)
1703 {
1704         struct cache_detail *cd = RPC_I(filp->f_path.dentry->d_inode)->private;
1705 
1706         return cache_poll(filp, wait, cd);
1707 }
1708 
1709 static long cache_ioctl_pipefs(struct file *filp,
1710                               unsigned int cmd, unsigned long arg)
1711 {
1712         struct inode *inode = filp->f_dentry->d_inode;
1713         struct cache_detail *cd = RPC_I(inode)->private;
1714 
1715         return cache_ioctl(inode, filp, cmd, arg, cd);
1716 }
1717 
1718 static int cache_open_pipefs(struct inode *inode, struct file *filp)
1719 {
1720         struct cache_detail *cd = RPC_I(inode)->private;
1721 
1722         return cache_open(inode, filp, cd);
1723 }
1724 
1725 static int cache_release_pipefs(struct inode *inode, struct file *filp)
1726 {
1727         struct cache_detail *cd = RPC_I(inode)->private;
1728 
1729         return cache_release(inode, filp, cd);
1730 }
1731 
1732 const struct file_operations cache_file_operations_pipefs = {
1733         .owner          = THIS_MODULE,
1734         .llseek         = no_llseek,
1735         .read           = cache_read_pipefs,
1736         .write          = cache_write_pipefs,
1737         .poll           = cache_poll_pipefs,
1738         .unlocked_ioctl = cache_ioctl_pipefs, /* for FIONREAD */
1739         .open           = cache_open_pipefs,
1740         .release        = cache_release_pipefs,
1741 };
1742 
1743 static int content_open_pipefs(struct inode *inode, struct file *filp)
1744 {
1745         struct cache_detail *cd = RPC_I(inode)->private;
1746 
1747         return content_open(inode, filp, cd);
1748 }
1749 
1750 static int content_release_pipefs(struct inode *inode, struct file *filp)
1751 {
1752         struct cache_detail *cd = RPC_I(inode)->private;
1753 
1754         return content_release(inode, filp, cd);
1755 }
1756 
1757 const struct file_operations content_file_operations_pipefs = {
1758         .open           = content_open_pipefs,
1759         .read           = seq_read,
1760         .llseek         = seq_lseek,
1761         .release        = content_release_pipefs,
1762 };
1763 
1764 static int open_flush_pipefs(struct inode *inode, struct file *filp)
1765 {
1766         struct cache_detail *cd = RPC_I(inode)->private;
1767 
1768         return open_flush(inode, filp, cd);
1769 }
1770 
1771 static int release_flush_pipefs(struct inode *inode, struct file *filp)
1772 {
1773         struct cache_detail *cd = RPC_I(inode)->private;
1774 
1775         return release_flush(inode, filp, cd);
1776 }
1777 
1778 static ssize_t read_flush_pipefs(struct file *filp, char __user *buf,
1779                             size_t count, loff_t *ppos)
1780 {
1781         struct cache_detail *cd = RPC_I(filp->f_path.dentry->d_inode)->private;
1782 
1783         return read_flush(filp, buf, count, ppos, cd);
1784 }
1785 
1786 static ssize_t write_flush_pipefs(struct file *filp,
1787                                   const char __user *buf,
1788                                   size_t count, loff_t *ppos)
1789 {
1790         struct cache_detail *cd = RPC_I(filp->f_path.dentry->d_inode)->private;
1791 
1792         return write_flush(filp, buf, count, ppos, cd);
1793 }
1794 
1795 const struct file_operations cache_flush_operations_pipefs = {
1796         .open           = open_flush_pipefs,
1797         .read           = read_flush_pipefs,
1798         .write          = write_flush_pipefs,
1799         .release        = release_flush_pipefs,
1800         .llseek         = no_llseek,
1801 };
1802 
1803 int sunrpc_cache_register_pipefs(struct dentry *parent,
1804                                  const char *name, umode_t umode,
1805                                  struct cache_detail *cd)
1806 {
1807         struct qstr q;
1808         struct dentry *dir;
1809         int ret = 0;
1810 
1811         q.name = name;
1812         q.len = strlen(name);
1813         q.hash = full_name_hash(q.name, q.len);
1814         dir = rpc_create_cache_dir(parent, &q, umode, cd);
1815         if (!IS_ERR(dir))
1816                 cd->u.pipefs.dir = dir;
1817         else
1818                 ret = PTR_ERR(dir);
1819         return ret;
1820 }
1821 EXPORT_SYMBOL_GPL(sunrpc_cache_register_pipefs);
1822 
1823 void sunrpc_cache_unregister_pipefs(struct cache_detail *cd)
1824 {
1825         rpc_remove_cache_dir(cd->u.pipefs.dir);
1826         cd->u.pipefs.dir = NULL;
1827 }
1828 EXPORT_SYMBOL_GPL(sunrpc_cache_unregister_pipefs);
1829 
1830 

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