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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 struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail,
 54                                        struct cache_head *key, int hash)
 55 {
 56         struct cache_head **head,  **hp;
 57         struct cache_head *new = NULL, *freeme = NULL;
 58 
 59         head = &detail->hash_table[hash];
 60 
 61         read_lock(&detail->hash_lock);
 62 
 63         for (hp=head; *hp != NULL ; hp = &(*hp)->next) {
 64                 struct cache_head *tmp = *hp;
 65                 if (detail->match(tmp, key)) {
 66                         if (cache_is_expired(detail, tmp))
 67                                 /* This entry is expired, we will discard it. */
 68                                 break;
 69                         cache_get(tmp);
 70                         read_unlock(&detail->hash_lock);
 71                         return tmp;
 72                 }
 73         }
 74         read_unlock(&detail->hash_lock);
 75         /* Didn't find anything, insert an empty entry */
 76 
 77         new = detail->alloc();
 78         if (!new)
 79                 return NULL;
 80         /* must fully initialise 'new', else
 81          * we might get lose if we need to
 82          * cache_put it soon.
 83          */
 84         cache_init(new);
 85         detail->init(new, key);
 86 
 87         write_lock(&detail->hash_lock);
 88 
 89         /* check if entry appeared while we slept */
 90         for (hp=head; *hp != NULL ; hp = &(*hp)->next) {
 91                 struct cache_head *tmp = *hp;
 92                 if (detail->match(tmp, key)) {
 93                         if (cache_is_expired(detail, tmp)) {
 94                                 *hp = tmp->next;
 95                                 tmp->next = NULL;
 96                                 detail->entries --;
 97                                 freeme = tmp;
 98                                 break;
 99                         }
100                         cache_get(tmp);
101                         write_unlock(&detail->hash_lock);
102                         cache_put(new, detail);
103                         return tmp;
104                 }
105         }
106         new->next = *head;
107         *head = new;
108         detail->entries++;
109         cache_get(new);
110         write_unlock(&detail->hash_lock);
111 
112         if (freeme)
113                 cache_put(freeme, detail);
114         return new;
115 }
116 EXPORT_SYMBOL_GPL(sunrpc_cache_lookup);
117 
118 
119 static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch);
120 
121 static void cache_fresh_locked(struct cache_head *head, time_t expiry)
122 {
123         head->expiry_time = expiry;
124         head->last_refresh = seconds_since_boot();
125         smp_wmb(); /* paired with smp_rmb() in cache_is_valid() */
126         set_bit(CACHE_VALID, &head->flags);
127 }
128 
129 static void cache_fresh_unlocked(struct cache_head *head,
130                                  struct cache_detail *detail)
131 {
132         if (test_and_clear_bit(CACHE_PENDING, &head->flags)) {
133                 cache_revisit_request(head);
134                 cache_dequeue(detail, head);
135         }
136 }
137 
138 struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
139                                        struct cache_head *new, struct cache_head *old, int hash)
140 {
141         /* The 'old' entry is to be replaced by 'new'.
142          * If 'old' is not VALID, we update it directly,
143          * otherwise we need to replace it
144          */
145         struct cache_head **head;
146         struct cache_head *tmp;
147 
148         if (!test_bit(CACHE_VALID, &old->flags)) {
149                 write_lock(&detail->hash_lock);
150                 if (!test_bit(CACHE_VALID, &old->flags)) {
151                         if (test_bit(CACHE_NEGATIVE, &new->flags))
152                                 set_bit(CACHE_NEGATIVE, &old->flags);
153                         else
154                                 detail->update(old, new);
155                         cache_fresh_locked(old, new->expiry_time);
156                         write_unlock(&detail->hash_lock);
157                         cache_fresh_unlocked(old, detail);
158                         return old;
159                 }
160                 write_unlock(&detail->hash_lock);
161         }
162         /* We need to insert a new entry */
163         tmp = detail->alloc();
164         if (!tmp) {
165                 cache_put(old, detail);
166                 return NULL;
167         }
168         cache_init(tmp);
169         detail->init(tmp, old);
170         head = &detail->hash_table[hash];
171 
172         write_lock(&detail->hash_lock);
173         if (test_bit(CACHE_NEGATIVE, &new->flags))
174                 set_bit(CACHE_NEGATIVE, &tmp->flags);
175         else
176                 detail->update(tmp, new);
177         tmp->next = *head;
178         *head = tmp;
179         detail->entries++;
180         cache_get(tmp);
181         cache_fresh_locked(tmp, new->expiry_time);
182         cache_fresh_locked(old, 0);
183         write_unlock(&detail->hash_lock);
184         cache_fresh_unlocked(tmp, detail);
185         cache_fresh_unlocked(old, detail);
186         cache_put(old, detail);
187         return tmp;
188 }
189 EXPORT_SYMBOL_GPL(sunrpc_cache_update);
190 
191 static int cache_make_upcall(struct cache_detail *cd, struct cache_head *h)
192 {
193         if (cd->cache_upcall)
194                 return cd->cache_upcall(cd, h);
195         return sunrpc_cache_pipe_upcall(cd, h);
196 }
197 
198 static inline int cache_is_valid(struct cache_head *h)
199 {
200         if (!test_bit(CACHE_VALID, &h->flags))
201                 return -EAGAIN;
202         else {
203                 /* entry is valid */
204                 if (test_bit(CACHE_NEGATIVE, &h->flags))
205                         return -ENOENT;
206                 else {
207                         /*
208                          * In combination with write barrier in
209                          * sunrpc_cache_update, ensures that anyone
210                          * using the cache entry after this sees the
211                          * updated contents:
212                          */
213                         smp_rmb();
214                         return 0;
215                 }
216         }
217 }
218 
219 static int try_to_negate_entry(struct cache_detail *detail, struct cache_head *h)
220 {
221         int rv;
222 
223         write_lock(&detail->hash_lock);
224         rv = cache_is_valid(h);
225         if (rv == -EAGAIN) {
226                 set_bit(CACHE_NEGATIVE, &h->flags);
227                 cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY);
228                 rv = -ENOENT;
229         }
230         write_unlock(&detail->hash_lock);
231         cache_fresh_unlocked(h, detail);
232         return rv;
233 }
234 
235 /*
236  * This is the generic cache management routine for all
237  * the authentication caches.
238  * It checks the currency of a cache item and will (later)
239  * initiate an upcall to fill it if needed.
240  *
241  *
242  * Returns 0 if the cache_head can be used, or cache_puts it and returns
243  * -EAGAIN if upcall is pending and request has been queued
244  * -ETIMEDOUT if upcall failed or request could not be queue or
245  *           upcall completed but item is still invalid (implying that
246  *           the cache item has been replaced with a newer one).
247  * -ENOENT if cache entry was negative
248  */
249 int cache_check(struct cache_detail *detail,
250                     struct cache_head *h, struct cache_req *rqstp)
251 {
252         int rv;
253         long refresh_age, age;
254 
255         /* First decide return status as best we can */
256         rv = cache_is_valid(h);
257 
258         /* now see if we want to start an upcall */
259         refresh_age = (h->expiry_time - h->last_refresh);
260         age = seconds_since_boot() - h->last_refresh;
261 
262         if (rqstp == NULL) {
263                 if (rv == -EAGAIN)
264                         rv = -ENOENT;
265         } else if (rv == -EAGAIN ||
266                    (h->expiry_time != 0 && age > refresh_age/2)) {
267                 dprintk("RPC:       Want update, refage=%ld, age=%ld\n",
268                                 refresh_age, age);
269                 if (!test_and_set_bit(CACHE_PENDING, &h->flags)) {
270                         switch (cache_make_upcall(detail, h)) {
271                         case -EINVAL:
272                                 rv = try_to_negate_entry(detail, h);
273                                 break;
274                         case -EAGAIN:
275                                 cache_fresh_unlocked(h, detail);
276                                 break;
277                         }
278                 }
279         }
280 
281         if (rv == -EAGAIN) {
282                 if (!cache_defer_req(rqstp, h)) {
283                         /*
284                          * Request was not deferred; handle it as best
285                          * we can ourselves:
286                          */
287                         rv = cache_is_valid(h);
288                         if (rv == -EAGAIN)
289                                 rv = -ETIMEDOUT;
290                 }
291         }
292         if (rv)
293                 cache_put(h, detail);
294         return rv;
295 }
296 EXPORT_SYMBOL_GPL(cache_check);
297 
298 /*
299  * caches need to be periodically cleaned.
300  * For this we maintain a list of cache_detail and
301  * a current pointer into that list and into the table
302  * for that entry.
303  *
304  * Each time cache_clean is called it finds the next non-empty entry
305  * in the current table and walks the list in that entry
306  * looking for entries that can be removed.
307  *
308  * An entry gets removed if:
309  * - The expiry is before current time
310  * - The last_refresh time is before the flush_time for that cache
311  *
312  * later we might drop old entries with non-NEVER expiry if that table
313  * is getting 'full' for some definition of 'full'
314  *
315  * The question of "how often to scan a table" is an interesting one
316  * and is answered in part by the use of the "nextcheck" field in the
317  * cache_detail.
318  * When a scan of a table begins, the nextcheck field is set to a time
319  * that is well into the future.
320  * While scanning, if an expiry time is found that is earlier than the
321  * current nextcheck time, nextcheck is set to that expiry time.
322  * If the flush_time is ever set to a time earlier than the nextcheck
323  * time, the nextcheck time is then set to that flush_time.
324  *
325  * A table is then only scanned if the current time is at least
326  * the nextcheck time.
327  *
328  */
329 
330 static LIST_HEAD(cache_list);
331 static DEFINE_SPINLOCK(cache_list_lock);
332 static struct cache_detail *current_detail;
333 static int current_index;
334 
335 static void do_cache_clean(struct work_struct *work);
336 static struct delayed_work cache_cleaner;
337 
338 void sunrpc_init_cache_detail(struct cache_detail *cd)
339 {
340         rwlock_init(&cd->hash_lock);
341         INIT_LIST_HEAD(&cd->queue);
342         spin_lock(&cache_list_lock);
343         cd->nextcheck = 0;
344         cd->entries = 0;
345         atomic_set(&cd->readers, 0);
346         cd->last_close = 0;
347         cd->last_warn = -1;
348         list_add(&cd->others, &cache_list);
349         spin_unlock(&cache_list_lock);
350 
351         /* start the cleaning process */
352         schedule_delayed_work(&cache_cleaner, 0);
353 }
354 EXPORT_SYMBOL_GPL(sunrpc_init_cache_detail);
355 
356 void sunrpc_destroy_cache_detail(struct cache_detail *cd)
357 {
358         cache_purge(cd);
359         spin_lock(&cache_list_lock);
360         write_lock(&cd->hash_lock);
361         if (cd->entries || atomic_read(&cd->inuse)) {
362                 write_unlock(&cd->hash_lock);
363                 spin_unlock(&cache_list_lock);
364                 goto out;
365         }
366         if (current_detail == cd)
367                 current_detail = NULL;
368         list_del_init(&cd->others);
369         write_unlock(&cd->hash_lock);
370         spin_unlock(&cache_list_lock);
371         if (list_empty(&cache_list)) {
372                 /* module must be being unloaded so its safe to kill the worker */
373                 cancel_delayed_work_sync(&cache_cleaner);
374         }
375         return;
376 out:
377         printk(KERN_ERR "nfsd: failed to unregister %s cache\n", cd->name);
378 }
379 EXPORT_SYMBOL_GPL(sunrpc_destroy_cache_detail);
380 
381 /* clean cache tries to find something to clean
382  * and cleans it.
383  * It returns 1 if it cleaned something,
384  *            0 if it didn't find anything this time
385  *           -1 if it fell off the end of the list.
386  */
387 static int cache_clean(void)
388 {
389         int rv = 0;
390         struct list_head *next;
391 
392         spin_lock(&cache_list_lock);
393 
394         /* find a suitable table if we don't already have one */
395         while (current_detail == NULL ||
396             current_index >= current_detail->hash_size) {
397                 if (current_detail)
398                         next = current_detail->others.next;
399                 else
400                         next = cache_list.next;
401                 if (next == &cache_list) {
402                         current_detail = NULL;
403                         spin_unlock(&cache_list_lock);
404                         return -1;
405                 }
406                 current_detail = list_entry(next, struct cache_detail, others);
407                 if (current_detail->nextcheck > seconds_since_boot())
408                         current_index = current_detail->hash_size;
409                 else {
410                         current_index = 0;
411                         current_detail->nextcheck = seconds_since_boot()+30*60;
412                 }
413         }
414 
415         /* find a non-empty bucket in the table */
416         while (current_detail &&
417                current_index < current_detail->hash_size &&
418                current_detail->hash_table[current_index] == NULL)
419                 current_index++;
420 
421         /* find a cleanable entry in the bucket and clean it, or set to next bucket */
422 
423         if (current_detail && current_index < current_detail->hash_size) {
424                 struct cache_head *ch, **cp;
425                 struct cache_detail *d;
426 
427                 write_lock(&current_detail->hash_lock);
428 
429                 /* Ok, now to clean this strand */
430 
431                 cp = & current_detail->hash_table[current_index];
432                 for (ch = *cp ; ch ; cp = & ch->next, ch = *cp) {
433                         if (current_detail->nextcheck > ch->expiry_time)
434                                 current_detail->nextcheck = ch->expiry_time+1;
435                         if (!cache_is_expired(current_detail, ch))
436                                 continue;
437 
438                         *cp = ch->next;
439                         ch->next = NULL;
440                         current_detail->entries--;
441                         rv = 1;
442                         break;
443                 }
444 
445                 write_unlock(&current_detail->hash_lock);
446                 d = current_detail;
447                 if (!ch)
448                         current_index ++;
449                 spin_unlock(&cache_list_lock);
450                 if (ch) {
451                         set_bit(CACHE_CLEANED, &ch->flags);
452                         cache_fresh_unlocked(ch, d);
453                         cache_put(ch, d);
454                 }
455         } else
456                 spin_unlock(&cache_list_lock);
457 
458         return rv;
459 }
460 
461 /*
462  * We want to regularly clean the cache, so we need to schedule some work ...
463  */
464 static void do_cache_clean(struct work_struct *work)
465 {
466         int delay = 5;
467         if (cache_clean() == -1)
468                 delay = round_jiffies_relative(30*HZ);
469 
470         if (list_empty(&cache_list))
471                 delay = 0;
472 
473         if (delay)
474                 schedule_delayed_work(&cache_cleaner, delay);
475 }
476 
477 
478 /*
479  * Clean all caches promptly.  This just calls cache_clean
480  * repeatedly until we are sure that every cache has had a chance to
481  * be fully cleaned
482  */
483 void cache_flush(void)
484 {
485         while (cache_clean() != -1)
486                 cond_resched();
487         while (cache_clean() != -1)
488                 cond_resched();
489 }
490 EXPORT_SYMBOL_GPL(cache_flush);
491 
492 void cache_purge(struct cache_detail *detail)
493 {
494         detail->flush_time = LONG_MAX;
495         detail->nextcheck = seconds_since_boot();
496         cache_flush();
497         detail->flush_time = 1;
498 }
499 EXPORT_SYMBOL_GPL(cache_purge);
500 
501 
502 /*
503  * Deferral and Revisiting of Requests.
504  *
505  * If a cache lookup finds a pending entry, we
506  * need to defer the request and revisit it later.
507  * All deferred requests are stored in a hash table,
508  * indexed by "struct cache_head *".
509  * As it may be wasteful to store a whole request
510  * structure, we allow the request to provide a
511  * deferred form, which must contain a
512  * 'struct cache_deferred_req'
513  * This cache_deferred_req contains a method to allow
514  * it to be revisited when cache info is available
515  */
516 
517 #define DFR_HASHSIZE    (PAGE_SIZE/sizeof(struct list_head))
518 #define DFR_HASH(item)  ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE)
519 
520 #define DFR_MAX 300     /* ??? */
521 
522 static DEFINE_SPINLOCK(cache_defer_lock);
523 static LIST_HEAD(cache_defer_list);
524 static struct hlist_head cache_defer_hash[DFR_HASHSIZE];
525 static int cache_defer_cnt;
526 
527 static void __unhash_deferred_req(struct cache_deferred_req *dreq)
528 {
529         hlist_del_init(&dreq->hash);
530         if (!list_empty(&dreq->recent)) {
531                 list_del_init(&dreq->recent);
532                 cache_defer_cnt--;
533         }
534 }
535 
536 static void __hash_deferred_req(struct cache_deferred_req *dreq, struct cache_head *item)
537 {
538         int hash = DFR_HASH(item);
539 
540         INIT_LIST_HEAD(&dreq->recent);
541         hlist_add_head(&dreq->hash, &cache_defer_hash[hash]);
542 }
543 
544 static void setup_deferral(struct cache_deferred_req *dreq,
545                            struct cache_head *item,
546                            int count_me)
547 {
548 
549         dreq->item = item;
550 
551         spin_lock(&cache_defer_lock);
552 
553         __hash_deferred_req(dreq, item);
554 
555         if (count_me) {
556                 cache_defer_cnt++;
557                 list_add(&dreq->recent, &cache_defer_list);
558         }
559 
560         spin_unlock(&cache_defer_lock);
561 
562 }
563 
564 struct thread_deferred_req {
565         struct cache_deferred_req handle;
566         struct completion completion;
567 };
568 
569 static void cache_restart_thread(struct cache_deferred_req *dreq, int too_many)
570 {
571         struct thread_deferred_req *dr =
572                 container_of(dreq, struct thread_deferred_req, handle);
573         complete(&dr->completion);
574 }
575 
576 static void cache_wait_req(struct cache_req *req, struct cache_head *item)
577 {
578         struct thread_deferred_req sleeper;
579         struct cache_deferred_req *dreq = &sleeper.handle;
580 
581         sleeper.completion = COMPLETION_INITIALIZER_ONSTACK(sleeper.completion);
582         dreq->revisit = cache_restart_thread;
583 
584         setup_deferral(dreq, item, 0);
585 
586         if (!test_bit(CACHE_PENDING, &item->flags) ||
587             wait_for_completion_interruptible_timeout(
588                     &sleeper.completion, req->thread_wait) <= 0) {
589                 /* The completion wasn't completed, so we need
590                  * to clean up
591                  */
592                 spin_lock(&cache_defer_lock);
593                 if (!hlist_unhashed(&sleeper.handle.hash)) {
594                         __unhash_deferred_req(&sleeper.handle);
595                         spin_unlock(&cache_defer_lock);
596                 } else {
597                         /* cache_revisit_request already removed
598                          * this from the hash table, but hasn't
599                          * called ->revisit yet.  It will very soon
600                          * and we need to wait for it.
601                          */
602                         spin_unlock(&cache_defer_lock);
603                         wait_for_completion(&sleeper.completion);
604                 }
605         }
606 }
607 
608 static void cache_limit_defers(void)
609 {
610         /* Make sure we haven't exceed the limit of allowed deferred
611          * requests.
612          */
613         struct cache_deferred_req *discard = NULL;
614 
615         if (cache_defer_cnt <= DFR_MAX)
616                 return;
617 
618         spin_lock(&cache_defer_lock);
619 
620         /* Consider removing either the first or the last */
621         if (cache_defer_cnt > DFR_MAX) {
622                 if (prandom_u32() & 1)
623                         discard = list_entry(cache_defer_list.next,
624                                              struct cache_deferred_req, recent);
625                 else
626                         discard = list_entry(cache_defer_list.prev,
627                                              struct cache_deferred_req, recent);
628                 __unhash_deferred_req(discard);
629         }
630         spin_unlock(&cache_defer_lock);
631         if (discard)
632                 discard->revisit(discard, 1);
633 }
634 
635 /* Return true if and only if a deferred request is queued. */
636 static bool cache_defer_req(struct cache_req *req, struct cache_head *item)
637 {
638         struct cache_deferred_req *dreq;
639 
640         if (req->thread_wait) {
641                 cache_wait_req(req, item);
642                 if (!test_bit(CACHE_PENDING, &item->flags))
643                         return false;
644         }
645         dreq = req->defer(req);
646         if (dreq == NULL)
647                 return false;
648         setup_deferral(dreq, item, 1);
649         if (!test_bit(CACHE_PENDING, &item->flags))
650                 /* Bit could have been cleared before we managed to
651                  * set up the deferral, so need to revisit just in case
652                  */
653                 cache_revisit_request(item);
654 
655         cache_limit_defers();
656         return true;
657 }
658 
659 static void cache_revisit_request(struct cache_head *item)
660 {
661         struct cache_deferred_req *dreq;
662         struct list_head pending;
663         struct hlist_node *tmp;
664         int hash = DFR_HASH(item);
665 
666         INIT_LIST_HEAD(&pending);
667         spin_lock(&cache_defer_lock);
668 
669         hlist_for_each_entry_safe(dreq, tmp, &cache_defer_hash[hash], hash)
670                 if (dreq->item == item) {
671                         __unhash_deferred_req(dreq);
672                         list_add(&dreq->recent, &pending);
673                 }
674 
675         spin_unlock(&cache_defer_lock);
676 
677         while (!list_empty(&pending)) {
678                 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
679                 list_del_init(&dreq->recent);
680                 dreq->revisit(dreq, 0);
681         }
682 }
683 
684 void cache_clean_deferred(void *owner)
685 {
686         struct cache_deferred_req *dreq, *tmp;
687         struct list_head pending;
688 
689 
690         INIT_LIST_HEAD(&pending);
691         spin_lock(&cache_defer_lock);
692 
693         list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) {
694                 if (dreq->owner == owner) {
695                         __unhash_deferred_req(dreq);
696                         list_add(&dreq->recent, &pending);
697                 }
698         }
699         spin_unlock(&cache_defer_lock);
700 
701         while (!list_empty(&pending)) {
702                 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
703                 list_del_init(&dreq->recent);
704                 dreq->revisit(dreq, 1);
705         }
706 }
707 
708 /*
709  * communicate with user-space
710  *
711  * We have a magic /proc file - /proc/sunrpc/<cachename>/channel.
712  * On read, you get a full request, or block.
713  * On write, an update request is processed.
714  * Poll works if anything to read, and always allows write.
715  *
716  * Implemented by linked list of requests.  Each open file has
717  * a ->private that also exists in this list.  New requests are added
718  * to the end and may wakeup and preceding readers.
719  * New readers are added to the head.  If, on read, an item is found with
720  * CACHE_UPCALLING clear, we free it from the list.
721  *
722  */
723 
724 static DEFINE_SPINLOCK(queue_lock);
725 static DEFINE_MUTEX(queue_io_mutex);
726 
727 struct cache_queue {
728         struct list_head        list;
729         int                     reader; /* if 0, then request */
730 };
731 struct cache_request {
732         struct cache_queue      q;
733         struct cache_head       *item;
734         char                    * buf;
735         int                     len;
736         int                     readers;
737 };
738 struct cache_reader {
739         struct cache_queue      q;
740         int                     offset; /* if non-0, we have a refcnt on next request */
741 };
742 
743 static int cache_request(struct cache_detail *detail,
744                                struct cache_request *crq)
745 {
746         char *bp = crq->buf;
747         int len = PAGE_SIZE;
748 
749         detail->cache_request(detail, crq->item, &bp, &len);
750         if (len < 0)
751                 return -EAGAIN;
752         return PAGE_SIZE - len;
753 }
754 
755 static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
756                           loff_t *ppos, struct cache_detail *cd)
757 {
758         struct cache_reader *rp = filp->private_data;
759         struct cache_request *rq;
760         struct inode *inode = file_inode(filp);
761         int err;
762 
763         if (count == 0)
764                 return 0;
765 
766         mutex_lock(&inode->i_mutex); /* protect against multiple concurrent
767                               * readers on this file */
768  again:
769         spin_lock(&queue_lock);
770         /* need to find next request */
771         while (rp->q.list.next != &cd->queue &&
772                list_entry(rp->q.list.next, struct cache_queue, list)
773                ->reader) {
774                 struct list_head *next = rp->q.list.next;
775                 list_move(&rp->q.list, next);
776         }
777         if (rp->q.list.next == &cd->queue) {
778                 spin_unlock(&queue_lock);
779                 mutex_unlock(&inode->i_mutex);
780                 WARN_ON_ONCE(rp->offset);
781                 return 0;
782         }
783         rq = container_of(rp->q.list.next, struct cache_request, q.list);
784         WARN_ON_ONCE(rq->q.reader);
785         if (rp->offset == 0)
786                 rq->readers++;
787         spin_unlock(&queue_lock);
788 
789         if (rq->len == 0) {
790                 err = cache_request(cd, rq);
791                 if (err < 0)
792                         goto out;
793                 rq->len = err;
794         }
795 
796         if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
797                 err = -EAGAIN;
798                 spin_lock(&queue_lock);
799                 list_move(&rp->q.list, &rq->q.list);
800                 spin_unlock(&queue_lock);
801         } else {
802                 if (rp->offset + count > rq->len)
803                         count = rq->len - rp->offset;
804                 err = -EFAULT;
805                 if (copy_to_user(buf, rq->buf + rp->offset, count))
806                         goto out;
807                 rp->offset += count;
808                 if (rp->offset >= rq->len) {
809                         rp->offset = 0;
810                         spin_lock(&queue_lock);
811                         list_move(&rp->q.list, &rq->q.list);
812                         spin_unlock(&queue_lock);
813                 }
814                 err = 0;
815         }
816  out:
817         if (rp->offset == 0) {
818                 /* need to release rq */
819                 spin_lock(&queue_lock);
820                 rq->readers--;
821                 if (rq->readers == 0 &&
822                     !test_bit(CACHE_PENDING, &rq->item->flags)) {
823                         list_del(&rq->q.list);
824                         spin_unlock(&queue_lock);
825                         cache_put(rq->item, cd);
826                         kfree(rq->buf);
827                         kfree(rq);
828                 } else
829                         spin_unlock(&queue_lock);
830         }
831         if (err == -EAGAIN)
832                 goto again;
833         mutex_unlock(&inode->i_mutex);
834         return err ? err :  count;
835 }
836 
837 static ssize_t cache_do_downcall(char *kaddr, const char __user *buf,
838                                  size_t count, struct cache_detail *cd)
839 {
840         ssize_t ret;
841 
842         if (count == 0)
843                 return -EINVAL;
844         if (copy_from_user(kaddr, buf, count))
845                 return -EFAULT;
846         kaddr[count] = '\0';
847         ret = cd->cache_parse(cd, kaddr, count);
848         if (!ret)
849                 ret = count;
850         return ret;
851 }
852 
853 static ssize_t cache_slow_downcall(const char __user *buf,
854                                    size_t count, struct cache_detail *cd)
855 {
856         static char write_buf[8192]; /* protected by queue_io_mutex */
857         ssize_t ret = -EINVAL;
858 
859         if (count >= sizeof(write_buf))
860                 goto out;
861         mutex_lock(&queue_io_mutex);
862         ret = cache_do_downcall(write_buf, buf, count, cd);
863         mutex_unlock(&queue_io_mutex);
864 out:
865         return ret;
866 }
867 
868 static ssize_t cache_downcall(struct address_space *mapping,
869                               const char __user *buf,
870                               size_t count, struct cache_detail *cd)
871 {
872         struct page *page;
873         char *kaddr;
874         ssize_t ret = -ENOMEM;
875 
876         if (count >= PAGE_CACHE_SIZE)
877                 goto out_slow;
878 
879         page = find_or_create_page(mapping, 0, GFP_KERNEL);
880         if (!page)
881                 goto out_slow;
882 
883         kaddr = kmap(page);
884         ret = cache_do_downcall(kaddr, buf, count, cd);
885         kunmap(page);
886         unlock_page(page);
887         page_cache_release(page);
888         return ret;
889 out_slow:
890         return cache_slow_downcall(buf, count, cd);
891 }
892 
893 static ssize_t cache_write(struct file *filp, const char __user *buf,
894                            size_t count, loff_t *ppos,
895                            struct cache_detail *cd)
896 {
897         struct address_space *mapping = filp->f_mapping;
898         struct inode *inode = file_inode(filp);
899         ssize_t ret = -EINVAL;
900 
901         if (!cd->cache_parse)
902                 goto out;
903 
904         mutex_lock(&inode->i_mutex);
905         ret = cache_downcall(mapping, buf, count, cd);
906         mutex_unlock(&inode->i_mutex);
907 out:
908         return ret;
909 }
910 
911 static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
912 
913 static unsigned int cache_poll(struct file *filp, poll_table *wait,
914                                struct cache_detail *cd)
915 {
916         unsigned int mask;
917         struct cache_reader *rp = filp->private_data;
918         struct cache_queue *cq;
919 
920         poll_wait(filp, &queue_wait, wait);
921 
922         /* alway allow write */
923         mask = POLLOUT | POLLWRNORM;
924 
925         if (!rp)
926                 return mask;
927 
928         spin_lock(&queue_lock);
929 
930         for (cq= &rp->q; &cq->list != &cd->queue;
931              cq = list_entry(cq->list.next, struct cache_queue, list))
932                 if (!cq->reader) {
933                         mask |= POLLIN | POLLRDNORM;
934                         break;
935                 }
936         spin_unlock(&queue_lock);
937         return mask;
938 }
939 
940 static int cache_ioctl(struct inode *ino, struct file *filp,
941                        unsigned int cmd, unsigned long arg,
942                        struct cache_detail *cd)
943 {
944         int len = 0;
945         struct cache_reader *rp = filp->private_data;
946         struct cache_queue *cq;
947 
948         if (cmd != FIONREAD || !rp)
949                 return -EINVAL;
950 
951         spin_lock(&queue_lock);
952 
953         /* only find the length remaining in current request,
954          * or the length of the next request
955          */
956         for (cq= &rp->q; &cq->list != &cd->queue;
957              cq = list_entry(cq->list.next, struct cache_queue, list))
958                 if (!cq->reader) {
959                         struct cache_request *cr =
960                                 container_of(cq, struct cache_request, q);
961                         len = cr->len - rp->offset;
962                         break;
963                 }
964         spin_unlock(&queue_lock);
965 
966         return put_user(len, (int __user *)arg);
967 }
968 
969 static int cache_open(struct inode *inode, struct file *filp,
970                       struct cache_detail *cd)
971 {
972         struct cache_reader *rp = NULL;
973 
974         if (!cd || !try_module_get(cd->owner))
975                 return -EACCES;
976         nonseekable_open(inode, filp);
977         if (filp->f_mode & FMODE_READ) {
978                 rp = kmalloc(sizeof(*rp), GFP_KERNEL);
979                 if (!rp) {
980                         module_put(cd->owner);
981                         return -ENOMEM;
982                 }
983                 rp->offset = 0;
984                 rp->q.reader = 1;
985                 atomic_inc(&cd->readers);
986                 spin_lock(&queue_lock);
987                 list_add(&rp->q.list, &cd->queue);
988                 spin_unlock(&queue_lock);
989         }
990         filp->private_data = rp;
991         return 0;
992 }
993 
994 static int cache_release(struct inode *inode, struct file *filp,
995                          struct cache_detail *cd)
996 {
997         struct cache_reader *rp = filp->private_data;
998 
999         if (rp) {
1000                 spin_lock(&queue_lock);
1001                 if (rp->offset) {
1002                         struct cache_queue *cq;
1003                         for (cq= &rp->q; &cq->list != &cd->queue;
1004                              cq = list_entry(cq->list.next, struct cache_queue, list))
1005                                 if (!cq->reader) {
1006                                         container_of(cq, struct cache_request, q)
1007                                                 ->readers--;
1008                                         break;
1009                                 }
1010                         rp->offset = 0;
1011                 }
1012                 list_del(&rp->q.list);
1013                 spin_unlock(&queue_lock);
1014 
1015                 filp->private_data = NULL;
1016                 kfree(rp);
1017 
1018                 cd->last_close = seconds_since_boot();
1019                 atomic_dec(&cd->readers);
1020         }
1021         module_put(cd->owner);
1022         return 0;
1023 }
1024 
1025 
1026 
1027 static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch)
1028 {
1029         struct cache_queue *cq, *tmp;
1030         struct cache_request *cr;
1031         struct list_head dequeued;
1032 
1033         INIT_LIST_HEAD(&dequeued);
1034         spin_lock(&queue_lock);
1035         list_for_each_entry_safe(cq, tmp, &detail->queue, list)
1036                 if (!cq->reader) {
1037                         cr = container_of(cq, struct cache_request, q);
1038                         if (cr->item != ch)
1039                                 continue;
1040                         if (test_bit(CACHE_PENDING, &ch->flags))
1041                                 /* Lost a race and it is pending again */
1042                                 break;
1043                         if (cr->readers != 0)
1044                                 continue;
1045                         list_move(&cr->q.list, &dequeued);
1046                 }
1047         spin_unlock(&queue_lock);
1048         while (!list_empty(&dequeued)) {
1049                 cr = list_entry(dequeued.next, struct cache_request, q.list);
1050                 list_del(&cr->q.list);
1051                 cache_put(cr->item, detail);
1052                 kfree(cr->buf);
1053                 kfree(cr);
1054         }
1055 }
1056 
1057 /*
1058  * Support routines for text-based upcalls.
1059  * Fields are separated by spaces.
1060  * Fields are either mangled to quote space tab newline slosh with slosh
1061  * or a hexified with a leading \x
1062  * Record is terminated with newline.
1063  *
1064  */
1065 
1066 void qword_add(char **bpp, int *lp, char *str)
1067 {
1068         char *bp = *bpp;
1069         int len = *lp;
1070         char c;
1071 
1072         if (len < 0) return;
1073 
1074         while ((c=*str++) && len)
1075                 switch(c) {
1076                 case ' ':
1077                 case '\t':
1078                 case '\n':
1079                 case '\\':
1080                         if (len >= 4) {
1081                                 *bp++ = '\\';
1082                                 *bp++ = '' + ((c & 0300)>>6);
1083                                 *bp++ = '' + ((c & 0070)>>3);
1084                                 *bp++ = '' + ((c & 0007)>>0);
1085                         }
1086                         len -= 4;
1087                         break;
1088                 default:
1089                         *bp++ = c;
1090                         len--;
1091                 }
1092         if (c || len <1) len = -1;
1093         else {
1094                 *bp++ = ' ';
1095                 len--;
1096         }
1097         *bpp = bp;
1098         *lp = len;
1099 }
1100 EXPORT_SYMBOL_GPL(qword_add);
1101 
1102 void qword_addhex(char **bpp, int *lp, char *buf, int blen)
1103 {
1104         char *bp = *bpp;
1105         int len = *lp;
1106 
1107         if (len < 0) return;
1108 
1109         if (len > 2) {
1110                 *bp++ = '\\';
1111                 *bp++ = 'x';
1112                 len -= 2;
1113                 while (blen && len >= 2) {
1114                         bp = hex_byte_pack(bp, *buf++);
1115                         len -= 2;
1116                         blen--;
1117                 }
1118         }
1119         if (blen || len<1) len = -1;
1120         else {
1121                 *bp++ = ' ';
1122                 len--;
1123         }
1124         *bpp = bp;
1125         *lp = len;
1126 }
1127 EXPORT_SYMBOL_GPL(qword_addhex);
1128 
1129 static void warn_no_listener(struct cache_detail *detail)
1130 {
1131         if (detail->last_warn != detail->last_close) {
1132                 detail->last_warn = detail->last_close;
1133                 if (detail->warn_no_listener)
1134                         detail->warn_no_listener(detail, detail->last_close != 0);
1135         }
1136 }
1137 
1138 static bool cache_listeners_exist(struct cache_detail *detail)
1139 {
1140         if (atomic_read(&detail->readers))
1141                 return true;
1142         if (detail->last_close == 0)
1143                 /* This cache was never opened */
1144                 return false;
1145         if (detail->last_close < seconds_since_boot() - 30)
1146                 /*
1147                  * We allow for the possibility that someone might
1148                  * restart a userspace daemon without restarting the
1149                  * server; but after 30 seconds, we give up.
1150                  */
1151                  return false;
1152         return true;
1153 }
1154 
1155 /*
1156  * register an upcall request to user-space and queue it up for read() by the
1157  * upcall daemon.
1158  *
1159  * Each request is at most one page long.
1160  */
1161 int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
1162 {
1163 
1164         char *buf;
1165         struct cache_request *crq;
1166         int ret = 0;
1167 
1168         if (!detail->cache_request)
1169                 return -EINVAL;
1170 
1171         if (!cache_listeners_exist(detail)) {
1172                 warn_no_listener(detail);
1173                 return -EINVAL;
1174         }
1175         if (test_bit(CACHE_CLEANED, &h->flags))
1176                 /* Too late to make an upcall */
1177                 return -EAGAIN;
1178 
1179         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1180         if (!buf)
1181                 return -EAGAIN;
1182 
1183         crq = kmalloc(sizeof (*crq), GFP_KERNEL);
1184         if (!crq) {
1185                 kfree(buf);
1186                 return -EAGAIN;
1187         }
1188 
1189         crq->q.reader = 0;
1190         crq->buf = buf;
1191         crq->len = 0;
1192         crq->readers = 0;
1193         spin_lock(&queue_lock);
1194         if (test_bit(CACHE_PENDING, &h->flags)) {
1195                 crq->item = cache_get(h);
1196                 list_add_tail(&crq->q.list, &detail->queue);
1197         } else
1198                 /* Lost a race, no longer PENDING, so don't enqueue */
1199                 ret = -EAGAIN;
1200         spin_unlock(&queue_lock);
1201         wake_up(&queue_wait);
1202         if (ret == -EAGAIN) {
1203                 kfree(buf);
1204                 kfree(crq);
1205         }
1206         return ret;
1207 }
1208 EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall);
1209 
1210 /*
1211  * parse a message from user-space and pass it
1212  * to an appropriate cache
1213  * Messages are, like requests, separated into fields by
1214  * spaces and dequotes as \xHEXSTRING or embedded \nnn octal
1215  *
1216  * Message is
1217  *   reply cachename expiry key ... content....
1218  *
1219  * key and content are both parsed by cache
1220  */
1221 
1222 int qword_get(char **bpp, char *dest, int bufsize)
1223 {
1224         /* return bytes copied, or -1 on error */
1225         char *bp = *bpp;
1226         int len = 0;
1227 
1228         while (*bp == ' ') bp++;
1229 
1230         if (bp[0] == '\\' && bp[1] == 'x') {
1231                 /* HEX STRING */
1232                 bp += 2;
1233                 while (len < bufsize - 1) {
1234                         int h, l;
1235 
1236                         h = hex_to_bin(bp[0]);
1237                         if (h < 0)
1238                                 break;
1239 
1240                         l = hex_to_bin(bp[1]);
1241                         if (l < 0)
1242                                 break;
1243 
1244                         *dest++ = (h << 4) | l;
1245                         bp += 2;
1246                         len++;
1247                 }
1248         } else {
1249                 /* text with \nnn octal quoting */
1250                 while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) {
1251                         if (*bp == '\\' &&
1252                             isodigit(bp[1]) && (bp[1] <= '3') &&
1253                             isodigit(bp[2]) &&
1254                             isodigit(bp[3])) {
1255                                 int byte = (*++bp -'');
1256                                 bp++;
1257                                 byte = (byte << 3) | (*bp++ - '');
1258                                 byte = (byte << 3) | (*bp++ - '');
1259                                 *dest++ = byte;
1260                                 len++;
1261                         } else {
1262                                 *dest++ = *bp++;
1263                                 len++;
1264                         }
1265                 }
1266         }
1267 
1268         if (*bp != ' ' && *bp != '\n' && *bp != '\0')
1269                 return -1;
1270         while (*bp == ' ') bp++;
1271         *bpp = bp;
1272         *dest = '\0';
1273         return len;
1274 }
1275 EXPORT_SYMBOL_GPL(qword_get);
1276 
1277 
1278 /*
1279  * support /proc/sunrpc/cache/$CACHENAME/content
1280  * as a seqfile.
1281  * We call ->cache_show passing NULL for the item to
1282  * get a header, then pass each real item in the cache
1283  */
1284 
1285 struct handle {
1286         struct cache_detail *cd;
1287 };
1288 
1289 static void *c_start(struct seq_file *m, loff_t *pos)
1290         __acquires(cd->hash_lock)
1291 {
1292         loff_t n = *pos;
1293         unsigned int hash, entry;
1294         struct cache_head *ch;
1295         struct cache_detail *cd = ((struct handle*)m->private)->cd;
1296 
1297 
1298         read_lock(&cd->hash_lock);
1299         if (!n--)
1300                 return SEQ_START_TOKEN;
1301         hash = n >> 32;
1302         entry = n & ((1LL<<32) - 1);
1303 
1304         for (ch=cd->hash_table[hash]; ch; ch=ch->next)
1305                 if (!entry--)
1306                         return ch;
1307         n &= ~((1LL<<32) - 1);
1308         do {
1309                 hash++;
1310                 n += 1LL<<32;
1311         } while(hash < cd->hash_size &&
1312                 cd->hash_table[hash]==NULL);
1313         if (hash >= cd->hash_size)
1314                 return NULL;
1315         *pos = n+1;
1316         return cd->hash_table[hash];
1317 }
1318 
1319 static void *c_next(struct seq_file *m, void *p, loff_t *pos)
1320 {
1321         struct cache_head *ch = p;
1322         int hash = (*pos >> 32);
1323         struct cache_detail *cd = ((struct handle*)m->private)->cd;
1324 
1325         if (p == SEQ_START_TOKEN)
1326                 hash = 0;
1327         else if (ch->next == NULL) {
1328                 hash++;
1329                 *pos += 1LL<<32;
1330         } else {
1331                 ++*pos;
1332                 return ch->next;
1333         }
1334         *pos &= ~((1LL<<32) - 1);
1335         while (hash < cd->hash_size &&
1336                cd->hash_table[hash] == NULL) {
1337                 hash++;
1338                 *pos += 1LL<<32;
1339         }
1340         if (hash >= cd->hash_size)
1341                 return NULL;
1342         ++*pos;
1343         return cd->hash_table[hash];
1344 }
1345 
1346 static void c_stop(struct seq_file *m, void *p)
1347         __releases(cd->hash_lock)
1348 {
1349         struct cache_detail *cd = ((struct handle*)m->private)->cd;
1350         read_unlock(&cd->hash_lock);
1351 }
1352 
1353 static int c_show(struct seq_file *m, void *p)
1354 {
1355         struct cache_head *cp = p;
1356         struct cache_detail *cd = ((struct handle*)m->private)->cd;
1357 
1358         if (p == SEQ_START_TOKEN)
1359                 return cd->cache_show(m, cd, NULL);
1360 
1361         ifdebug(CACHE)
1362                 seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n",
1363                            convert_to_wallclock(cp->expiry_time),
1364                            atomic_read(&cp->ref.refcount), cp->flags);
1365         cache_get(cp);
1366         if (cache_check(cd, cp, NULL))
1367                 /* cache_check does a cache_put on failure */
1368                 seq_printf(m, "# ");
1369         else {
1370                 if (cache_is_expired(cd, cp))
1371                         seq_printf(m, "# ");
1372                 cache_put(cp, cd);
1373         }
1374 
1375         return cd->cache_show(m, cd, cp);
1376 }
1377 
1378 static const struct seq_operations cache_content_op = {
1379         .start  = c_start,
1380         .next   = c_next,
1381         .stop   = c_stop,
1382         .show   = c_show,
1383 };
1384 
1385 static int content_open(struct inode *inode, struct file *file,
1386                         struct cache_detail *cd)
1387 {
1388         struct handle *han;
1389 
1390         if (!cd || !try_module_get(cd->owner))
1391                 return -EACCES;
1392         han = __seq_open_private(file, &cache_content_op, sizeof(*han));
1393         if (han == NULL) {
1394                 module_put(cd->owner);
1395                 return -ENOMEM;
1396         }
1397 
1398         han->cd = cd;
1399         return 0;
1400 }
1401 
1402 static int content_release(struct inode *inode, struct file *file,
1403                 struct cache_detail *cd)
1404 {
1405         int ret = seq_release_private(inode, file);
1406         module_put(cd->owner);
1407         return ret;
1408 }
1409 
1410 static int open_flush(struct inode *inode, struct file *file,
1411                         struct cache_detail *cd)
1412 {
1413         if (!cd || !try_module_get(cd->owner))
1414                 return -EACCES;
1415         return nonseekable_open(inode, file);
1416 }
1417 
1418 static int release_flush(struct inode *inode, struct file *file,
1419                         struct cache_detail *cd)
1420 {
1421         module_put(cd->owner);
1422         return 0;
1423 }
1424 
1425 static ssize_t read_flush(struct file *file, char __user *buf,
1426                           size_t count, loff_t *ppos,
1427                           struct cache_detail *cd)
1428 {
1429         char tbuf[22];
1430         unsigned long p = *ppos;
1431         size_t len;
1432 
1433         snprintf(tbuf, sizeof(tbuf), "%lu\n", convert_to_wallclock(cd->flush_time));
1434         len = strlen(tbuf);
1435         if (p >= len)
1436                 return 0;
1437         len -= p;
1438         if (len > count)
1439                 len = count;
1440         if (copy_to_user(buf, (void*)(tbuf+p), len))
1441                 return -EFAULT;
1442         *ppos += len;
1443         return len;
1444 }
1445 
1446 static ssize_t write_flush(struct file *file, const char __user *buf,
1447                            size_t count, loff_t *ppos,
1448                            struct cache_detail *cd)
1449 {
1450         char tbuf[20];
1451         char *bp, *ep;
1452 
1453         if (*ppos || count > sizeof(tbuf)-1)
1454                 return -EINVAL;
1455         if (copy_from_user(tbuf, buf, count))
1456                 return -EFAULT;
1457         tbuf[count] = 0;
1458         simple_strtoul(tbuf, &ep, 0);
1459         if (*ep && *ep != '\n')
1460                 return -EINVAL;
1461 
1462         bp = tbuf;
1463         cd->flush_time = get_expiry(&bp);
1464         cd->nextcheck = seconds_since_boot();
1465         cache_flush();
1466 
1467         *ppos += count;
1468         return count;
1469 }
1470 
1471 static ssize_t cache_read_procfs(struct file *filp, char __user *buf,
1472                                  size_t count, loff_t *ppos)
1473 {
1474         struct cache_detail *cd = PDE_DATA(file_inode(filp));
1475 
1476         return cache_read(filp, buf, count, ppos, cd);
1477 }
1478 
1479 static ssize_t cache_write_procfs(struct file *filp, const char __user *buf,
1480                                   size_t count, loff_t *ppos)
1481 {
1482         struct cache_detail *cd = PDE_DATA(file_inode(filp));
1483 
1484         return cache_write(filp, buf, count, ppos, cd);
1485 }
1486 
1487 static unsigned int cache_poll_procfs(struct file *filp, poll_table *wait)
1488 {
1489         struct cache_detail *cd = PDE_DATA(file_inode(filp));
1490 
1491         return cache_poll(filp, wait, cd);
1492 }
1493 
1494 static long cache_ioctl_procfs(struct file *filp,
1495                                unsigned int cmd, unsigned long arg)
1496 {
1497         struct inode *inode = file_inode(filp);
1498         struct cache_detail *cd = PDE_DATA(inode);
1499 
1500         return cache_ioctl(inode, filp, cmd, arg, cd);
1501 }
1502 
1503 static int cache_open_procfs(struct inode *inode, struct file *filp)
1504 {
1505         struct cache_detail *cd = PDE_DATA(inode);
1506 
1507         return cache_open(inode, filp, cd);
1508 }
1509 
1510 static int cache_release_procfs(struct inode *inode, struct file *filp)
1511 {
1512         struct cache_detail *cd = PDE_DATA(inode);
1513 
1514         return cache_release(inode, filp, cd);
1515 }
1516 
1517 static const struct file_operations cache_file_operations_procfs = {
1518         .owner          = THIS_MODULE,
1519         .llseek         = no_llseek,
1520         .read           = cache_read_procfs,
1521         .write          = cache_write_procfs,
1522         .poll           = cache_poll_procfs,
1523         .unlocked_ioctl = cache_ioctl_procfs, /* for FIONREAD */
1524         .open           = cache_open_procfs,
1525         .release        = cache_release_procfs,
1526 };
1527 
1528 static int content_open_procfs(struct inode *inode, struct file *filp)
1529 {
1530         struct cache_detail *cd = PDE_DATA(inode);
1531 
1532         return content_open(inode, filp, cd);
1533 }
1534 
1535 static int content_release_procfs(struct inode *inode, struct file *filp)
1536 {
1537         struct cache_detail *cd = PDE_DATA(inode);
1538 
1539         return content_release(inode, filp, cd);
1540 }
1541 
1542 static const struct file_operations content_file_operations_procfs = {
1543         .open           = content_open_procfs,
1544         .read           = seq_read,
1545         .llseek         = seq_lseek,
1546         .release        = content_release_procfs,
1547 };
1548 
1549 static int open_flush_procfs(struct inode *inode, struct file *filp)
1550 {
1551         struct cache_detail *cd = PDE_DATA(inode);
1552 
1553         return open_flush(inode, filp, cd);
1554 }
1555 
1556 static int release_flush_procfs(struct inode *inode, struct file *filp)
1557 {
1558         struct cache_detail *cd = PDE_DATA(inode);
1559 
1560         return release_flush(inode, filp, cd);
1561 }
1562 
1563 static ssize_t read_flush_procfs(struct file *filp, char __user *buf,
1564                             size_t count, loff_t *ppos)
1565 {
1566         struct cache_detail *cd = PDE_DATA(file_inode(filp));
1567 
1568         return read_flush(filp, buf, count, ppos, cd);
1569 }
1570 
1571 static ssize_t write_flush_procfs(struct file *filp,
1572                                   const char __user *buf,
1573                                   size_t count, loff_t *ppos)
1574 {
1575         struct cache_detail *cd = PDE_DATA(file_inode(filp));
1576 
1577         return write_flush(filp, buf, count, ppos, cd);
1578 }
1579 
1580 static const struct file_operations cache_flush_operations_procfs = {
1581         .open           = open_flush_procfs,
1582         .read           = read_flush_procfs,
1583         .write          = write_flush_procfs,
1584         .release        = release_flush_procfs,
1585         .llseek         = no_llseek,
1586 };
1587 
1588 static void remove_cache_proc_entries(struct cache_detail *cd, struct net *net)
1589 {
1590         struct sunrpc_net *sn;
1591 
1592         if (cd->u.procfs.proc_ent == NULL)
1593                 return;
1594         if (cd->u.procfs.flush_ent)
1595                 remove_proc_entry("flush", cd->u.procfs.proc_ent);
1596         if (cd->u.procfs.channel_ent)
1597                 remove_proc_entry("channel", cd->u.procfs.proc_ent);
1598         if (cd->u.procfs.content_ent)
1599                 remove_proc_entry("content", cd->u.procfs.proc_ent);
1600         cd->u.procfs.proc_ent = NULL;
1601         sn = net_generic(net, sunrpc_net_id);
1602         remove_proc_entry(cd->name, sn->proc_net_rpc);
1603 }
1604 
1605 #ifdef CONFIG_PROC_FS
1606 static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1607 {
1608         struct proc_dir_entry *p;
1609         struct sunrpc_net *sn;
1610 
1611         sn = net_generic(net, sunrpc_net_id);
1612         cd->u.procfs.proc_ent = proc_mkdir(cd->name, sn->proc_net_rpc);
1613         if (cd->u.procfs.proc_ent == NULL)
1614                 goto out_nomem;
1615         cd->u.procfs.channel_ent = NULL;
1616         cd->u.procfs.content_ent = NULL;
1617 
1618         p = proc_create_data("flush", S_IFREG|S_IRUSR|S_IWUSR,
1619                              cd->u.procfs.proc_ent,
1620                              &cache_flush_operations_procfs, cd);
1621         cd->u.procfs.flush_ent = p;
1622         if (p == NULL)
1623                 goto out_nomem;
1624 
1625         if (cd->cache_request || cd->cache_parse) {
1626                 p = proc_create_data("channel", S_IFREG|S_IRUSR|S_IWUSR,
1627                                      cd->u.procfs.proc_ent,
1628                                      &cache_file_operations_procfs, cd);
1629                 cd->u.procfs.channel_ent = p;
1630                 if (p == NULL)
1631                         goto out_nomem;
1632         }
1633         if (cd->cache_show) {
1634                 p = proc_create_data("content", S_IFREG|S_IRUSR,
1635                                 cd->u.procfs.proc_ent,
1636                                 &content_file_operations_procfs, cd);
1637                 cd->u.procfs.content_ent = p;
1638                 if (p == NULL)
1639                         goto out_nomem;
1640         }
1641         return 0;
1642 out_nomem:
1643         remove_cache_proc_entries(cd, net);
1644         return -ENOMEM;
1645 }
1646 #else /* CONFIG_PROC_FS */
1647 static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1648 {
1649         return 0;
1650 }
1651 #endif
1652 
1653 void __init cache_initialize(void)
1654 {
1655         INIT_DEFERRABLE_WORK(&cache_cleaner, do_cache_clean);
1656 }
1657 
1658 int cache_register_net(struct cache_detail *cd, struct net *net)
1659 {
1660         int ret;
1661 
1662         sunrpc_init_cache_detail(cd);
1663         ret = create_cache_proc_entries(cd, net);
1664         if (ret)
1665                 sunrpc_destroy_cache_detail(cd);
1666         return ret;
1667 }
1668 EXPORT_SYMBOL_GPL(cache_register_net);
1669 
1670 void cache_unregister_net(struct cache_detail *cd, struct net *net)
1671 {
1672         remove_cache_proc_entries(cd, net);
1673         sunrpc_destroy_cache_detail(cd);
1674 }
1675 EXPORT_SYMBOL_GPL(cache_unregister_net);
1676 
1677 struct cache_detail *cache_create_net(struct cache_detail *tmpl, struct net *net)
1678 {
1679         struct cache_detail *cd;
1680 
1681         cd = kmemdup(tmpl, sizeof(struct cache_detail), GFP_KERNEL);
1682         if (cd == NULL)
1683                 return ERR_PTR(-ENOMEM);
1684 
1685         cd->hash_table = kzalloc(cd->hash_size * sizeof(struct cache_head *),
1686                                  GFP_KERNEL);
1687         if (cd->hash_table == NULL) {
1688                 kfree(cd);
1689                 return ERR_PTR(-ENOMEM);
1690         }
1691         cd->net = net;
1692         return cd;
1693 }
1694 EXPORT_SYMBOL_GPL(cache_create_net);
1695 
1696 void cache_destroy_net(struct cache_detail *cd, struct net *net)
1697 {
1698         kfree(cd->hash_table);
1699         kfree(cd);
1700 }
1701 EXPORT_SYMBOL_GPL(cache_destroy_net);
1702 
1703 static ssize_t cache_read_pipefs(struct file *filp, char __user *buf,
1704                                  size_t count, loff_t *ppos)
1705 {
1706         struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1707 
1708         return cache_read(filp, buf, count, ppos, cd);
1709 }
1710 
1711 static ssize_t cache_write_pipefs(struct file *filp, const char __user *buf,
1712                                   size_t count, loff_t *ppos)
1713 {
1714         struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1715 
1716         return cache_write(filp, buf, count, ppos, cd);
1717 }
1718 
1719 static unsigned int cache_poll_pipefs(struct file *filp, poll_table *wait)
1720 {
1721         struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1722 
1723         return cache_poll(filp, wait, cd);
1724 }
1725 
1726 static long cache_ioctl_pipefs(struct file *filp,
1727                               unsigned int cmd, unsigned long arg)
1728 {
1729         struct inode *inode = file_inode(filp);
1730         struct cache_detail *cd = RPC_I(inode)->private;
1731 
1732         return cache_ioctl(inode, filp, cmd, arg, cd);
1733 }
1734 
1735 static int cache_open_pipefs(struct inode *inode, struct file *filp)
1736 {
1737         struct cache_detail *cd = RPC_I(inode)->private;
1738 
1739         return cache_open(inode, filp, cd);
1740 }
1741 
1742 static int cache_release_pipefs(struct inode *inode, struct file *filp)
1743 {
1744         struct cache_detail *cd = RPC_I(inode)->private;
1745 
1746         return cache_release(inode, filp, cd);
1747 }
1748 
1749 const struct file_operations cache_file_operations_pipefs = {
1750         .owner          = THIS_MODULE,
1751         .llseek         = no_llseek,
1752         .read           = cache_read_pipefs,
1753         .write          = cache_write_pipefs,
1754         .poll           = cache_poll_pipefs,
1755         .unlocked_ioctl = cache_ioctl_pipefs, /* for FIONREAD */
1756         .open           = cache_open_pipefs,
1757         .release        = cache_release_pipefs,
1758 };
1759 
1760 static int content_open_pipefs(struct inode *inode, struct file *filp)
1761 {
1762         struct cache_detail *cd = RPC_I(inode)->private;
1763 
1764         return content_open(inode, filp, cd);
1765 }
1766 
1767 static int content_release_pipefs(struct inode *inode, struct file *filp)
1768 {
1769         struct cache_detail *cd = RPC_I(inode)->private;
1770 
1771         return content_release(inode, filp, cd);
1772 }
1773 
1774 const struct file_operations content_file_operations_pipefs = {
1775         .open           = content_open_pipefs,
1776         .read           = seq_read,
1777         .llseek         = seq_lseek,
1778         .release        = content_release_pipefs,
1779 };
1780 
1781 static int open_flush_pipefs(struct inode *inode, struct file *filp)
1782 {
1783         struct cache_detail *cd = RPC_I(inode)->private;
1784 
1785         return open_flush(inode, filp, cd);
1786 }
1787 
1788 static int release_flush_pipefs(struct inode *inode, struct file *filp)
1789 {
1790         struct cache_detail *cd = RPC_I(inode)->private;
1791 
1792         return release_flush(inode, filp, cd);
1793 }
1794 
1795 static ssize_t read_flush_pipefs(struct file *filp, char __user *buf,
1796                             size_t count, loff_t *ppos)
1797 {
1798         struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1799 
1800         return read_flush(filp, buf, count, ppos, cd);
1801 }
1802 
1803 static ssize_t write_flush_pipefs(struct file *filp,
1804                                   const char __user *buf,
1805                                   size_t count, loff_t *ppos)
1806 {
1807         struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1808 
1809         return write_flush(filp, buf, count, ppos, cd);
1810 }
1811 
1812 const struct file_operations cache_flush_operations_pipefs = {
1813         .open           = open_flush_pipefs,
1814         .read           = read_flush_pipefs,
1815         .write          = write_flush_pipefs,
1816         .release        = release_flush_pipefs,
1817         .llseek         = no_llseek,
1818 };
1819 
1820 int sunrpc_cache_register_pipefs(struct dentry *parent,
1821                                  const char *name, umode_t umode,
1822                                  struct cache_detail *cd)
1823 {
1824         struct dentry *dir = rpc_create_cache_dir(parent, name, umode, cd);
1825         if (IS_ERR(dir))
1826                 return PTR_ERR(dir);
1827         cd->u.pipefs.dir = dir;
1828         return 0;
1829 }
1830 EXPORT_SYMBOL_GPL(sunrpc_cache_register_pipefs);
1831 
1832 void sunrpc_cache_unregister_pipefs(struct cache_detail *cd)
1833 {
1834         rpc_remove_cache_dir(cd->u.pipefs.dir);
1835         cd->u.pipefs.dir = NULL;
1836 }
1837 EXPORT_SYMBOL_GPL(sunrpc_cache_unregister_pipefs);
1838 
1839 

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