1 // SPDX-License-Identifier: GPL-2.0-only
5 * Generic code for various authentication-related caches
6 * used by sunrpc clients and servers.
8 * Copyright (C) 2002 Neil Brown <neilb@cse.unsw.edu.au>
11 #include <linux/types.h>
13 #include <linux/file.h>
14 #include <linux/slab.h>
15 #include <linux/signal.h>
16 #include <linux/sched.h>
17 #include <linux/kmod.h>
18 #include <linux/list.h>
19 #include <linux/module.h>
20 #include <linux/ctype.h>
21 #include <linux/string_helpers.h>
22 #include <linux/uaccess.h>
23 #include <linux/poll.h>
24 #include <linux/seq_file.h>
25 #include <linux/proc_fs.h>
26 #include <linux/net.h>
27 #include <linux/workqueue.h>
28 #include <linux/mutex.h>
29 #include <linux/pagemap.h>
30 #include <asm/ioctls.h>
31 #include <linux/sunrpc/types.h>
32 #include <linux/sunrpc/cache.h>
33 #include <linux/sunrpc/stats.h>
34 #include <linux/sunrpc/rpc_pipe_fs.h>
35 #include <trace/events/sunrpc.h>
38 #define RPCDBG_FACILITY RPCDBG_CACHE
40 static bool cache_defer_req(struct cache_req *req, struct cache_head *item);
41 static void cache_revisit_request(struct cache_head *item);
43 static void cache_init(struct cache_head *h, struct cache_detail *detail)
45 time64_t now = seconds_since_boot();
46 INIT_HLIST_NODE(&h->cache_list);
49 h->expiry_time = now + CACHE_NEW_EXPIRY;
50 if (now <= detail->flush_time)
51 /* ensure it isn't already expired */
52 now = detail->flush_time + 1;
53 h->last_refresh = now;
56 static void cache_fresh_unlocked(struct cache_head *head,
57 struct cache_detail *detail);
59 static struct cache_head *sunrpc_cache_find_rcu(struct cache_detail *detail,
60 struct cache_head *key,
63 struct hlist_head *head = &detail->hash_table[hash];
64 struct cache_head *tmp;
67 hlist_for_each_entry_rcu(tmp, head, cache_list) {
68 if (!detail->match(tmp, key))
70 if (test_bit(CACHE_VALID, &tmp->flags) &&
71 cache_is_expired(detail, tmp))
73 tmp = cache_get_rcu(tmp);
81 static void sunrpc_begin_cache_remove_entry(struct cache_head *ch,
82 struct cache_detail *cd)
84 /* Must be called under cd->hash_lock */
85 hlist_del_init_rcu(&ch->cache_list);
86 set_bit(CACHE_CLEANED, &ch->flags);
90 static void sunrpc_end_cache_remove_entry(struct cache_head *ch,
91 struct cache_detail *cd)
93 cache_fresh_unlocked(ch, cd);
97 static struct cache_head *sunrpc_cache_add_entry(struct cache_detail *detail,
98 struct cache_head *key,
101 struct cache_head *new, *tmp, *freeme = NULL;
102 struct hlist_head *head = &detail->hash_table[hash];
104 new = detail->alloc();
107 /* must fully initialise 'new', else
108 * we might get lose if we need to
111 cache_init(new, detail);
112 detail->init(new, key);
114 spin_lock(&detail->hash_lock);
116 /* check if entry appeared while we slept */
117 hlist_for_each_entry_rcu(tmp, head, cache_list,
118 lockdep_is_held(&detail->hash_lock)) {
119 if (!detail->match(tmp, key))
121 if (test_bit(CACHE_VALID, &tmp->flags) &&
122 cache_is_expired(detail, tmp)) {
123 sunrpc_begin_cache_remove_entry(tmp, detail);
124 trace_cache_entry_expired(detail, tmp);
129 spin_unlock(&detail->hash_lock);
130 cache_put(new, detail);
134 hlist_add_head_rcu(&new->cache_list, head);
137 spin_unlock(&detail->hash_lock);
140 sunrpc_end_cache_remove_entry(freeme, detail);
144 struct cache_head *sunrpc_cache_lookup_rcu(struct cache_detail *detail,
145 struct cache_head *key, int hash)
147 struct cache_head *ret;
149 ret = sunrpc_cache_find_rcu(detail, key, hash);
152 /* Didn't find anything, insert an empty entry */
153 return sunrpc_cache_add_entry(detail, key, hash);
155 EXPORT_SYMBOL_GPL(sunrpc_cache_lookup_rcu);
157 static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch);
159 static void cache_fresh_locked(struct cache_head *head, time64_t expiry,
160 struct cache_detail *detail)
162 time64_t now = seconds_since_boot();
163 if (now <= detail->flush_time)
164 /* ensure it isn't immediately treated as expired */
165 now = detail->flush_time + 1;
166 head->expiry_time = expiry;
167 head->last_refresh = now;
168 smp_wmb(); /* paired with smp_rmb() in cache_is_valid() */
169 set_bit(CACHE_VALID, &head->flags);
172 static void cache_fresh_unlocked(struct cache_head *head,
173 struct cache_detail *detail)
175 if (test_and_clear_bit(CACHE_PENDING, &head->flags)) {
176 cache_revisit_request(head);
177 cache_dequeue(detail, head);
181 static void cache_make_negative(struct cache_detail *detail,
182 struct cache_head *h)
184 set_bit(CACHE_NEGATIVE, &h->flags);
185 trace_cache_entry_make_negative(detail, h);
188 static void cache_entry_update(struct cache_detail *detail,
189 struct cache_head *h,
190 struct cache_head *new)
192 if (!test_bit(CACHE_NEGATIVE, &new->flags)) {
193 detail->update(h, new);
194 trace_cache_entry_update(detail, h);
196 cache_make_negative(detail, h);
200 struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
201 struct cache_head *new, struct cache_head *old, int hash)
203 /* The 'old' entry is to be replaced by 'new'.
204 * If 'old' is not VALID, we update it directly,
205 * otherwise we need to replace it
207 struct cache_head *tmp;
209 if (!test_bit(CACHE_VALID, &old->flags)) {
210 spin_lock(&detail->hash_lock);
211 if (!test_bit(CACHE_VALID, &old->flags)) {
212 cache_entry_update(detail, old, new);
213 cache_fresh_locked(old, new->expiry_time, detail);
214 spin_unlock(&detail->hash_lock);
215 cache_fresh_unlocked(old, detail);
218 spin_unlock(&detail->hash_lock);
220 /* We need to insert a new entry */
221 tmp = detail->alloc();
223 cache_put(old, detail);
226 cache_init(tmp, detail);
227 detail->init(tmp, old);
229 spin_lock(&detail->hash_lock);
230 cache_entry_update(detail, tmp, new);
231 hlist_add_head(&tmp->cache_list, &detail->hash_table[hash]);
234 cache_fresh_locked(tmp, new->expiry_time, detail);
235 cache_fresh_locked(old, 0, detail);
236 spin_unlock(&detail->hash_lock);
237 cache_fresh_unlocked(tmp, detail);
238 cache_fresh_unlocked(old, detail);
239 cache_put(old, detail);
242 EXPORT_SYMBOL_GPL(sunrpc_cache_update);
244 static inline int cache_is_valid(struct cache_head *h)
246 if (!test_bit(CACHE_VALID, &h->flags))
250 if (test_bit(CACHE_NEGATIVE, &h->flags))
254 * In combination with write barrier in
255 * sunrpc_cache_update, ensures that anyone
256 * using the cache entry after this sees the
265 static int try_to_negate_entry(struct cache_detail *detail, struct cache_head *h)
269 spin_lock(&detail->hash_lock);
270 rv = cache_is_valid(h);
272 cache_make_negative(detail, h);
273 cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY,
277 spin_unlock(&detail->hash_lock);
278 cache_fresh_unlocked(h, detail);
283 * This is the generic cache management routine for all
284 * the authentication caches.
285 * It checks the currency of a cache item and will (later)
286 * initiate an upcall to fill it if needed.
289 * Returns 0 if the cache_head can be used, or cache_puts it and returns
290 * -EAGAIN if upcall is pending and request has been queued
291 * -ETIMEDOUT if upcall failed or request could not be queue or
292 * upcall completed but item is still invalid (implying that
293 * the cache item has been replaced with a newer one).
294 * -ENOENT if cache entry was negative
296 int cache_check(struct cache_detail *detail,
297 struct cache_head *h, struct cache_req *rqstp)
300 time64_t refresh_age, age;
302 /* First decide return status as best we can */
303 rv = cache_is_valid(h);
305 /* now see if we want to start an upcall */
306 refresh_age = (h->expiry_time - h->last_refresh);
307 age = seconds_since_boot() - h->last_refresh;
312 } else if (rv == -EAGAIN ||
313 (h->expiry_time != 0 && age > refresh_age/2)) {
314 dprintk("RPC: Want update, refage=%lld, age=%lld\n",
316 switch (detail->cache_upcall(detail, h)) {
318 rv = try_to_negate_entry(detail, h);
321 cache_fresh_unlocked(h, detail);
327 if (!cache_defer_req(rqstp, h)) {
329 * Request was not deferred; handle it as best
332 rv = cache_is_valid(h);
338 cache_put(h, detail);
341 EXPORT_SYMBOL_GPL(cache_check);
344 * caches need to be periodically cleaned.
345 * For this we maintain a list of cache_detail and
346 * a current pointer into that list and into the table
349 * Each time cache_clean is called it finds the next non-empty entry
350 * in the current table and walks the list in that entry
351 * looking for entries that can be removed.
353 * An entry gets removed if:
354 * - The expiry is before current time
355 * - The last_refresh time is before the flush_time for that cache
357 * later we might drop old entries with non-NEVER expiry if that table
358 * is getting 'full' for some definition of 'full'
360 * The question of "how often to scan a table" is an interesting one
361 * and is answered in part by the use of the "nextcheck" field in the
363 * When a scan of a table begins, the nextcheck field is set to a time
364 * that is well into the future.
365 * While scanning, if an expiry time is found that is earlier than the
366 * current nextcheck time, nextcheck is set to that expiry time.
367 * If the flush_time is ever set to a time earlier than the nextcheck
368 * time, the nextcheck time is then set to that flush_time.
370 * A table is then only scanned if the current time is at least
371 * the nextcheck time.
375 static LIST_HEAD(cache_list);
376 static DEFINE_SPINLOCK(cache_list_lock);
377 static struct cache_detail *current_detail;
378 static int current_index;
380 static void do_cache_clean(struct work_struct *work);
381 static struct delayed_work cache_cleaner;
383 void sunrpc_init_cache_detail(struct cache_detail *cd)
385 spin_lock_init(&cd->hash_lock);
386 INIT_LIST_HEAD(&cd->queue);
387 spin_lock(&cache_list_lock);
390 atomic_set(&cd->writers, 0);
393 list_add(&cd->others, &cache_list);
394 spin_unlock(&cache_list_lock);
396 /* start the cleaning process */
397 queue_delayed_work(system_power_efficient_wq, &cache_cleaner, 0);
399 EXPORT_SYMBOL_GPL(sunrpc_init_cache_detail);
401 void sunrpc_destroy_cache_detail(struct cache_detail *cd)
404 spin_lock(&cache_list_lock);
405 spin_lock(&cd->hash_lock);
406 if (current_detail == cd)
407 current_detail = NULL;
408 list_del_init(&cd->others);
409 spin_unlock(&cd->hash_lock);
410 spin_unlock(&cache_list_lock);
411 if (list_empty(&cache_list)) {
412 /* module must be being unloaded so its safe to kill the worker */
413 cancel_delayed_work_sync(&cache_cleaner);
416 EXPORT_SYMBOL_GPL(sunrpc_destroy_cache_detail);
418 /* clean cache tries to find something to clean
420 * It returns 1 if it cleaned something,
421 * 0 if it didn't find anything this time
422 * -1 if it fell off the end of the list.
424 static int cache_clean(void)
427 struct list_head *next;
429 spin_lock(&cache_list_lock);
431 /* find a suitable table if we don't already have one */
432 while (current_detail == NULL ||
433 current_index >= current_detail->hash_size) {
435 next = current_detail->others.next;
437 next = cache_list.next;
438 if (next == &cache_list) {
439 current_detail = NULL;
440 spin_unlock(&cache_list_lock);
443 current_detail = list_entry(next, struct cache_detail, others);
444 if (current_detail->nextcheck > seconds_since_boot())
445 current_index = current_detail->hash_size;
448 current_detail->nextcheck = seconds_since_boot()+30*60;
452 /* find a non-empty bucket in the table */
453 while (current_detail &&
454 current_index < current_detail->hash_size &&
455 hlist_empty(¤t_detail->hash_table[current_index]))
458 /* find a cleanable entry in the bucket and clean it, or set to next bucket */
460 if (current_detail && current_index < current_detail->hash_size) {
461 struct cache_head *ch = NULL;
462 struct cache_detail *d;
463 struct hlist_head *head;
464 struct hlist_node *tmp;
466 spin_lock(¤t_detail->hash_lock);
468 /* Ok, now to clean this strand */
470 head = ¤t_detail->hash_table[current_index];
471 hlist_for_each_entry_safe(ch, tmp, head, cache_list) {
472 if (current_detail->nextcheck > ch->expiry_time)
473 current_detail->nextcheck = ch->expiry_time+1;
474 if (!cache_is_expired(current_detail, ch))
477 sunrpc_begin_cache_remove_entry(ch, current_detail);
478 trace_cache_entry_expired(current_detail, ch);
483 spin_unlock(¤t_detail->hash_lock);
487 spin_unlock(&cache_list_lock);
489 sunrpc_end_cache_remove_entry(ch, d);
491 spin_unlock(&cache_list_lock);
497 * We want to regularly clean the cache, so we need to schedule some work ...
499 static void do_cache_clean(struct work_struct *work)
503 if (list_empty(&cache_list))
506 if (cache_clean() == -1)
507 delay = round_jiffies_relative(30*HZ);
511 queue_delayed_work(system_power_efficient_wq, &cache_cleaner, delay);
516 * Clean all caches promptly. This just calls cache_clean
517 * repeatedly until we are sure that every cache has had a chance to
520 void cache_flush(void)
522 while (cache_clean() != -1)
524 while (cache_clean() != -1)
527 EXPORT_SYMBOL_GPL(cache_flush);
529 void cache_purge(struct cache_detail *detail)
531 struct cache_head *ch = NULL;
532 struct hlist_head *head = NULL;
535 spin_lock(&detail->hash_lock);
536 if (!detail->entries) {
537 spin_unlock(&detail->hash_lock);
541 dprintk("RPC: %d entries in %s cache\n", detail->entries, detail->name);
542 for (i = 0; i < detail->hash_size; i++) {
543 head = &detail->hash_table[i];
544 while (!hlist_empty(head)) {
545 ch = hlist_entry(head->first, struct cache_head,
547 sunrpc_begin_cache_remove_entry(ch, detail);
548 spin_unlock(&detail->hash_lock);
549 sunrpc_end_cache_remove_entry(ch, detail);
550 spin_lock(&detail->hash_lock);
553 spin_unlock(&detail->hash_lock);
555 EXPORT_SYMBOL_GPL(cache_purge);
559 * Deferral and Revisiting of Requests.
561 * If a cache lookup finds a pending entry, we
562 * need to defer the request and revisit it later.
563 * All deferred requests are stored in a hash table,
564 * indexed by "struct cache_head *".
565 * As it may be wasteful to store a whole request
566 * structure, we allow the request to provide a
567 * deferred form, which must contain a
568 * 'struct cache_deferred_req'
569 * This cache_deferred_req contains a method to allow
570 * it to be revisited when cache info is available
573 #define DFR_HASHSIZE (PAGE_SIZE/sizeof(struct list_head))
574 #define DFR_HASH(item) ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE)
576 #define DFR_MAX 300 /* ??? */
578 static DEFINE_SPINLOCK(cache_defer_lock);
579 static LIST_HEAD(cache_defer_list);
580 static struct hlist_head cache_defer_hash[DFR_HASHSIZE];
581 static int cache_defer_cnt;
583 static void __unhash_deferred_req(struct cache_deferred_req *dreq)
585 hlist_del_init(&dreq->hash);
586 if (!list_empty(&dreq->recent)) {
587 list_del_init(&dreq->recent);
592 static void __hash_deferred_req(struct cache_deferred_req *dreq, struct cache_head *item)
594 int hash = DFR_HASH(item);
596 INIT_LIST_HEAD(&dreq->recent);
597 hlist_add_head(&dreq->hash, &cache_defer_hash[hash]);
600 static void setup_deferral(struct cache_deferred_req *dreq,
601 struct cache_head *item,
607 spin_lock(&cache_defer_lock);
609 __hash_deferred_req(dreq, item);
613 list_add(&dreq->recent, &cache_defer_list);
616 spin_unlock(&cache_defer_lock);
620 struct thread_deferred_req {
621 struct cache_deferred_req handle;
622 struct completion completion;
625 static void cache_restart_thread(struct cache_deferred_req *dreq, int too_many)
627 struct thread_deferred_req *dr =
628 container_of(dreq, struct thread_deferred_req, handle);
629 complete(&dr->completion);
632 static void cache_wait_req(struct cache_req *req, struct cache_head *item)
634 struct thread_deferred_req sleeper;
635 struct cache_deferred_req *dreq = &sleeper.handle;
637 sleeper.completion = COMPLETION_INITIALIZER_ONSTACK(sleeper.completion);
638 dreq->revisit = cache_restart_thread;
640 setup_deferral(dreq, item, 0);
642 if (!test_bit(CACHE_PENDING, &item->flags) ||
643 wait_for_completion_interruptible_timeout(
644 &sleeper.completion, req->thread_wait) <= 0) {
645 /* The completion wasn't completed, so we need
648 spin_lock(&cache_defer_lock);
649 if (!hlist_unhashed(&sleeper.handle.hash)) {
650 __unhash_deferred_req(&sleeper.handle);
651 spin_unlock(&cache_defer_lock);
653 /* cache_revisit_request already removed
654 * this from the hash table, but hasn't
655 * called ->revisit yet. It will very soon
656 * and we need to wait for it.
658 spin_unlock(&cache_defer_lock);
659 wait_for_completion(&sleeper.completion);
664 static void cache_limit_defers(void)
666 /* Make sure we haven't exceed the limit of allowed deferred
669 struct cache_deferred_req *discard = NULL;
671 if (cache_defer_cnt <= DFR_MAX)
674 spin_lock(&cache_defer_lock);
676 /* Consider removing either the first or the last */
677 if (cache_defer_cnt > DFR_MAX) {
678 if (prandom_u32() & 1)
679 discard = list_entry(cache_defer_list.next,
680 struct cache_deferred_req, recent);
682 discard = list_entry(cache_defer_list.prev,
683 struct cache_deferred_req, recent);
684 __unhash_deferred_req(discard);
686 spin_unlock(&cache_defer_lock);
688 discard->revisit(discard, 1);
691 /* Return true if and only if a deferred request is queued. */
692 static bool cache_defer_req(struct cache_req *req, struct cache_head *item)
694 struct cache_deferred_req *dreq;
696 if (req->thread_wait) {
697 cache_wait_req(req, item);
698 if (!test_bit(CACHE_PENDING, &item->flags))
701 dreq = req->defer(req);
704 setup_deferral(dreq, item, 1);
705 if (!test_bit(CACHE_PENDING, &item->flags))
706 /* Bit could have been cleared before we managed to
707 * set up the deferral, so need to revisit just in case
709 cache_revisit_request(item);
711 cache_limit_defers();
715 static void cache_revisit_request(struct cache_head *item)
717 struct cache_deferred_req *dreq;
718 struct list_head pending;
719 struct hlist_node *tmp;
720 int hash = DFR_HASH(item);
722 INIT_LIST_HEAD(&pending);
723 spin_lock(&cache_defer_lock);
725 hlist_for_each_entry_safe(dreq, tmp, &cache_defer_hash[hash], hash)
726 if (dreq->item == item) {
727 __unhash_deferred_req(dreq);
728 list_add(&dreq->recent, &pending);
731 spin_unlock(&cache_defer_lock);
733 while (!list_empty(&pending)) {
734 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
735 list_del_init(&dreq->recent);
736 dreq->revisit(dreq, 0);
740 void cache_clean_deferred(void *owner)
742 struct cache_deferred_req *dreq, *tmp;
743 struct list_head pending;
746 INIT_LIST_HEAD(&pending);
747 spin_lock(&cache_defer_lock);
749 list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) {
750 if (dreq->owner == owner) {
751 __unhash_deferred_req(dreq);
752 list_add(&dreq->recent, &pending);
755 spin_unlock(&cache_defer_lock);
757 while (!list_empty(&pending)) {
758 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
759 list_del_init(&dreq->recent);
760 dreq->revisit(dreq, 1);
765 * communicate with user-space
767 * We have a magic /proc file - /proc/net/rpc/<cachename>/channel.
768 * On read, you get a full request, or block.
769 * On write, an update request is processed.
770 * Poll works if anything to read, and always allows write.
772 * Implemented by linked list of requests. Each open file has
773 * a ->private that also exists in this list. New requests are added
774 * to the end and may wakeup and preceding readers.
775 * New readers are added to the head. If, on read, an item is found with
776 * CACHE_UPCALLING clear, we free it from the list.
780 static DEFINE_SPINLOCK(queue_lock);
781 static DEFINE_MUTEX(queue_io_mutex);
784 struct list_head list;
785 int reader; /* if 0, then request */
787 struct cache_request {
788 struct cache_queue q;
789 struct cache_head *item;
794 struct cache_reader {
795 struct cache_queue q;
796 int offset; /* if non-0, we have a refcnt on next request */
799 static int cache_request(struct cache_detail *detail,
800 struct cache_request *crq)
805 detail->cache_request(detail, crq->item, &bp, &len);
808 return PAGE_SIZE - len;
811 static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
812 loff_t *ppos, struct cache_detail *cd)
814 struct cache_reader *rp = filp->private_data;
815 struct cache_request *rq;
816 struct inode *inode = file_inode(filp);
822 inode_lock(inode); /* protect against multiple concurrent
823 * readers on this file */
825 spin_lock(&queue_lock);
826 /* need to find next request */
827 while (rp->q.list.next != &cd->queue &&
828 list_entry(rp->q.list.next, struct cache_queue, list)
830 struct list_head *next = rp->q.list.next;
831 list_move(&rp->q.list, next);
833 if (rp->q.list.next == &cd->queue) {
834 spin_unlock(&queue_lock);
836 WARN_ON_ONCE(rp->offset);
839 rq = container_of(rp->q.list.next, struct cache_request, q.list);
840 WARN_ON_ONCE(rq->q.reader);
843 spin_unlock(&queue_lock);
846 err = cache_request(cd, rq);
852 if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
854 spin_lock(&queue_lock);
855 list_move(&rp->q.list, &rq->q.list);
856 spin_unlock(&queue_lock);
858 if (rp->offset + count > rq->len)
859 count = rq->len - rp->offset;
861 if (copy_to_user(buf, rq->buf + rp->offset, count))
864 if (rp->offset >= rq->len) {
866 spin_lock(&queue_lock);
867 list_move(&rp->q.list, &rq->q.list);
868 spin_unlock(&queue_lock);
873 if (rp->offset == 0) {
874 /* need to release rq */
875 spin_lock(&queue_lock);
877 if (rq->readers == 0 &&
878 !test_bit(CACHE_PENDING, &rq->item->flags)) {
879 list_del(&rq->q.list);
880 spin_unlock(&queue_lock);
881 cache_put(rq->item, cd);
885 spin_unlock(&queue_lock);
890 return err ? err : count;
893 static ssize_t cache_do_downcall(char *kaddr, const char __user *buf,
894 size_t count, struct cache_detail *cd)
900 if (copy_from_user(kaddr, buf, count))
903 ret = cd->cache_parse(cd, kaddr, count);
909 static ssize_t cache_slow_downcall(const char __user *buf,
910 size_t count, struct cache_detail *cd)
912 static char write_buf[32768]; /* protected by queue_io_mutex */
913 ssize_t ret = -EINVAL;
915 if (count >= sizeof(write_buf))
917 mutex_lock(&queue_io_mutex);
918 ret = cache_do_downcall(write_buf, buf, count, cd);
919 mutex_unlock(&queue_io_mutex);
924 static ssize_t cache_downcall(struct address_space *mapping,
925 const char __user *buf,
926 size_t count, struct cache_detail *cd)
930 ssize_t ret = -ENOMEM;
932 if (count >= PAGE_SIZE)
935 page = find_or_create_page(mapping, 0, GFP_KERNEL);
940 ret = cache_do_downcall(kaddr, buf, count, cd);
946 return cache_slow_downcall(buf, count, cd);
949 static ssize_t cache_write(struct file *filp, const char __user *buf,
950 size_t count, loff_t *ppos,
951 struct cache_detail *cd)
953 struct address_space *mapping = filp->f_mapping;
954 struct inode *inode = file_inode(filp);
955 ssize_t ret = -EINVAL;
957 if (!cd->cache_parse)
961 ret = cache_downcall(mapping, buf, count, cd);
967 static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
969 static __poll_t cache_poll(struct file *filp, poll_table *wait,
970 struct cache_detail *cd)
973 struct cache_reader *rp = filp->private_data;
974 struct cache_queue *cq;
976 poll_wait(filp, &queue_wait, wait);
978 /* alway allow write */
979 mask = EPOLLOUT | EPOLLWRNORM;
984 spin_lock(&queue_lock);
986 for (cq= &rp->q; &cq->list != &cd->queue;
987 cq = list_entry(cq->list.next, struct cache_queue, list))
989 mask |= EPOLLIN | EPOLLRDNORM;
992 spin_unlock(&queue_lock);
996 static int cache_ioctl(struct inode *ino, struct file *filp,
997 unsigned int cmd, unsigned long arg,
998 struct cache_detail *cd)
1001 struct cache_reader *rp = filp->private_data;
1002 struct cache_queue *cq;
1004 if (cmd != FIONREAD || !rp)
1007 spin_lock(&queue_lock);
1009 /* only find the length remaining in current request,
1010 * or the length of the next request
1012 for (cq= &rp->q; &cq->list != &cd->queue;
1013 cq = list_entry(cq->list.next, struct cache_queue, list))
1015 struct cache_request *cr =
1016 container_of(cq, struct cache_request, q);
1017 len = cr->len - rp->offset;
1020 spin_unlock(&queue_lock);
1022 return put_user(len, (int __user *)arg);
1025 static int cache_open(struct inode *inode, struct file *filp,
1026 struct cache_detail *cd)
1028 struct cache_reader *rp = NULL;
1030 if (!cd || !try_module_get(cd->owner))
1032 nonseekable_open(inode, filp);
1033 if (filp->f_mode & FMODE_READ) {
1034 rp = kmalloc(sizeof(*rp), GFP_KERNEL);
1036 module_put(cd->owner);
1042 spin_lock(&queue_lock);
1043 list_add(&rp->q.list, &cd->queue);
1044 spin_unlock(&queue_lock);
1046 if (filp->f_mode & FMODE_WRITE)
1047 atomic_inc(&cd->writers);
1048 filp->private_data = rp;
1052 static int cache_release(struct inode *inode, struct file *filp,
1053 struct cache_detail *cd)
1055 struct cache_reader *rp = filp->private_data;
1058 spin_lock(&queue_lock);
1060 struct cache_queue *cq;
1061 for (cq= &rp->q; &cq->list != &cd->queue;
1062 cq = list_entry(cq->list.next, struct cache_queue, list))
1064 container_of(cq, struct cache_request, q)
1070 list_del(&rp->q.list);
1071 spin_unlock(&queue_lock);
1073 filp->private_data = NULL;
1077 if (filp->f_mode & FMODE_WRITE) {
1078 atomic_dec(&cd->writers);
1079 cd->last_close = seconds_since_boot();
1081 module_put(cd->owner);
1087 static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch)
1089 struct cache_queue *cq, *tmp;
1090 struct cache_request *cr;
1091 struct list_head dequeued;
1093 INIT_LIST_HEAD(&dequeued);
1094 spin_lock(&queue_lock);
1095 list_for_each_entry_safe(cq, tmp, &detail->queue, list)
1097 cr = container_of(cq, struct cache_request, q);
1100 if (test_bit(CACHE_PENDING, &ch->flags))
1101 /* Lost a race and it is pending again */
1103 if (cr->readers != 0)
1105 list_move(&cr->q.list, &dequeued);
1107 spin_unlock(&queue_lock);
1108 while (!list_empty(&dequeued)) {
1109 cr = list_entry(dequeued.next, struct cache_request, q.list);
1110 list_del(&cr->q.list);
1111 cache_put(cr->item, detail);
1118 * Support routines for text-based upcalls.
1119 * Fields are separated by spaces.
1120 * Fields are either mangled to quote space tab newline slosh with slosh
1121 * or a hexified with a leading \x
1122 * Record is terminated with newline.
1126 void qword_add(char **bpp, int *lp, char *str)
1132 if (len < 0) return;
1134 ret = string_escape_str(str, bp, len, ESCAPE_OCTAL, "\\ \n\t");
1147 EXPORT_SYMBOL_GPL(qword_add);
1149 void qword_addhex(char **bpp, int *lp, char *buf, int blen)
1154 if (len < 0) return;
1160 while (blen && len >= 2) {
1161 bp = hex_byte_pack(bp, *buf++);
1166 if (blen || len<1) len = -1;
1174 EXPORT_SYMBOL_GPL(qword_addhex);
1176 static void warn_no_listener(struct cache_detail *detail)
1178 if (detail->last_warn != detail->last_close) {
1179 detail->last_warn = detail->last_close;
1180 if (detail->warn_no_listener)
1181 detail->warn_no_listener(detail, detail->last_close != 0);
1185 static bool cache_listeners_exist(struct cache_detail *detail)
1187 if (atomic_read(&detail->writers))
1189 if (detail->last_close == 0)
1190 /* This cache was never opened */
1192 if (detail->last_close < seconds_since_boot() - 30)
1194 * We allow for the possibility that someone might
1195 * restart a userspace daemon without restarting the
1196 * server; but after 30 seconds, we give up.
1203 * register an upcall request to user-space and queue it up for read() by the
1206 * Each request is at most one page long.
1208 static int cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
1211 struct cache_request *crq;
1214 if (test_bit(CACHE_CLEANED, &h->flags))
1215 /* Too late to make an upcall */
1218 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1222 crq = kmalloc(sizeof (*crq), GFP_KERNEL);
1232 spin_lock(&queue_lock);
1233 if (test_bit(CACHE_PENDING, &h->flags)) {
1234 crq->item = cache_get(h);
1235 list_add_tail(&crq->q.list, &detail->queue);
1236 trace_cache_entry_upcall(detail, h);
1238 /* Lost a race, no longer PENDING, so don't enqueue */
1240 spin_unlock(&queue_lock);
1241 wake_up(&queue_wait);
1242 if (ret == -EAGAIN) {
1249 int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
1251 if (test_and_set_bit(CACHE_PENDING, &h->flags))
1253 return cache_pipe_upcall(detail, h);
1255 EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall);
1257 int sunrpc_cache_pipe_upcall_timeout(struct cache_detail *detail,
1258 struct cache_head *h)
1260 if (!cache_listeners_exist(detail)) {
1261 warn_no_listener(detail);
1262 trace_cache_entry_no_listener(detail, h);
1265 return sunrpc_cache_pipe_upcall(detail, h);
1267 EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall_timeout);
1270 * parse a message from user-space and pass it
1271 * to an appropriate cache
1272 * Messages are, like requests, separated into fields by
1273 * spaces and dequotes as \xHEXSTRING or embedded \nnn octal
1276 * reply cachename expiry key ... content....
1278 * key and content are both parsed by cache
1281 int qword_get(char **bpp, char *dest, int bufsize)
1283 /* return bytes copied, or -1 on error */
1287 while (*bp == ' ') bp++;
1289 if (bp[0] == '\\' && bp[1] == 'x') {
1292 while (len < bufsize - 1) {
1295 h = hex_to_bin(bp[0]);
1299 l = hex_to_bin(bp[1]);
1303 *dest++ = (h << 4) | l;
1308 /* text with \nnn octal quoting */
1309 while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) {
1311 isodigit(bp[1]) && (bp[1] <= '3') &&
1314 int byte = (*++bp -'0');
1316 byte = (byte << 3) | (*bp++ - '0');
1317 byte = (byte << 3) | (*bp++ - '0');
1327 if (*bp != ' ' && *bp != '\n' && *bp != '\0')
1329 while (*bp == ' ') bp++;
1334 EXPORT_SYMBOL_GPL(qword_get);
1338 * support /proc/net/rpc/$CACHENAME/content
1340 * We call ->cache_show passing NULL for the item to
1341 * get a header, then pass each real item in the cache
1344 static void *__cache_seq_start(struct seq_file *m, loff_t *pos)
1347 unsigned int hash, entry;
1348 struct cache_head *ch;
1349 struct cache_detail *cd = m->private;
1352 return SEQ_START_TOKEN;
1354 entry = n & ((1LL<<32) - 1);
1356 hlist_for_each_entry_rcu(ch, &cd->hash_table[hash], cache_list)
1359 n &= ~((1LL<<32) - 1);
1363 } while(hash < cd->hash_size &&
1364 hlist_empty(&cd->hash_table[hash]));
1365 if (hash >= cd->hash_size)
1368 return hlist_entry_safe(rcu_dereference_raw(
1369 hlist_first_rcu(&cd->hash_table[hash])),
1370 struct cache_head, cache_list);
1373 static void *cache_seq_next(struct seq_file *m, void *p, loff_t *pos)
1375 struct cache_head *ch = p;
1376 int hash = (*pos >> 32);
1377 struct cache_detail *cd = m->private;
1379 if (p == SEQ_START_TOKEN)
1381 else if (ch->cache_list.next == NULL) {
1386 return hlist_entry_safe(rcu_dereference_raw(
1387 hlist_next_rcu(&ch->cache_list)),
1388 struct cache_head, cache_list);
1390 *pos &= ~((1LL<<32) - 1);
1391 while (hash < cd->hash_size &&
1392 hlist_empty(&cd->hash_table[hash])) {
1396 if (hash >= cd->hash_size)
1399 return hlist_entry_safe(rcu_dereference_raw(
1400 hlist_first_rcu(&cd->hash_table[hash])),
1401 struct cache_head, cache_list);
1404 void *cache_seq_start_rcu(struct seq_file *m, loff_t *pos)
1408 return __cache_seq_start(m, pos);
1410 EXPORT_SYMBOL_GPL(cache_seq_start_rcu);
1412 void *cache_seq_next_rcu(struct seq_file *file, void *p, loff_t *pos)
1414 return cache_seq_next(file, p, pos);
1416 EXPORT_SYMBOL_GPL(cache_seq_next_rcu);
1418 void cache_seq_stop_rcu(struct seq_file *m, void *p)
1423 EXPORT_SYMBOL_GPL(cache_seq_stop_rcu);
1425 static int c_show(struct seq_file *m, void *p)
1427 struct cache_head *cp = p;
1428 struct cache_detail *cd = m->private;
1430 if (p == SEQ_START_TOKEN)
1431 return cd->cache_show(m, cd, NULL);
1434 seq_printf(m, "# expiry=%lld refcnt=%d flags=%lx\n",
1435 convert_to_wallclock(cp->expiry_time),
1436 kref_read(&cp->ref), cp->flags);
1438 if (cache_check(cd, cp, NULL))
1439 /* cache_check does a cache_put on failure */
1442 if (cache_is_expired(cd, cp))
1447 return cd->cache_show(m, cd, cp);
1450 static const struct seq_operations cache_content_op = {
1451 .start = cache_seq_start_rcu,
1452 .next = cache_seq_next_rcu,
1453 .stop = cache_seq_stop_rcu,
1457 static int content_open(struct inode *inode, struct file *file,
1458 struct cache_detail *cd)
1460 struct seq_file *seq;
1463 if (!cd || !try_module_get(cd->owner))
1466 err = seq_open(file, &cache_content_op);
1468 module_put(cd->owner);
1472 seq = file->private_data;
1477 static int content_release(struct inode *inode, struct file *file,
1478 struct cache_detail *cd)
1480 int ret = seq_release(inode, file);
1481 module_put(cd->owner);
1485 static int open_flush(struct inode *inode, struct file *file,
1486 struct cache_detail *cd)
1488 if (!cd || !try_module_get(cd->owner))
1490 return nonseekable_open(inode, file);
1493 static int release_flush(struct inode *inode, struct file *file,
1494 struct cache_detail *cd)
1496 module_put(cd->owner);
1500 static ssize_t read_flush(struct file *file, char __user *buf,
1501 size_t count, loff_t *ppos,
1502 struct cache_detail *cd)
1507 len = snprintf(tbuf, sizeof(tbuf), "%llu\n",
1508 convert_to_wallclock(cd->flush_time));
1509 return simple_read_from_buffer(buf, count, ppos, tbuf, len);
1512 static ssize_t write_flush(struct file *file, const char __user *buf,
1513 size_t count, loff_t *ppos,
1514 struct cache_detail *cd)
1520 if (*ppos || count > sizeof(tbuf)-1)
1522 if (copy_from_user(tbuf, buf, count))
1525 simple_strtoul(tbuf, &ep, 0);
1526 if (*ep && *ep != '\n')
1528 /* Note that while we check that 'buf' holds a valid number,
1529 * we always ignore the value and just flush everything.
1530 * Making use of the number leads to races.
1533 now = seconds_since_boot();
1534 /* Always flush everything, so behave like cache_purge()
1535 * Do this by advancing flush_time to the current time,
1536 * or by one second if it has already reached the current time.
1537 * Newly added cache entries will always have ->last_refresh greater
1538 * that ->flush_time, so they don't get flushed prematurely.
1541 if (cd->flush_time >= now)
1542 now = cd->flush_time + 1;
1544 cd->flush_time = now;
1545 cd->nextcheck = now;
1555 static ssize_t cache_read_procfs(struct file *filp, char __user *buf,
1556 size_t count, loff_t *ppos)
1558 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1560 return cache_read(filp, buf, count, ppos, cd);
1563 static ssize_t cache_write_procfs(struct file *filp, const char __user *buf,
1564 size_t count, loff_t *ppos)
1566 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1568 return cache_write(filp, buf, count, ppos, cd);
1571 static __poll_t cache_poll_procfs(struct file *filp, poll_table *wait)
1573 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1575 return cache_poll(filp, wait, cd);
1578 static long cache_ioctl_procfs(struct file *filp,
1579 unsigned int cmd, unsigned long arg)
1581 struct inode *inode = file_inode(filp);
1582 struct cache_detail *cd = PDE_DATA(inode);
1584 return cache_ioctl(inode, filp, cmd, arg, cd);
1587 static int cache_open_procfs(struct inode *inode, struct file *filp)
1589 struct cache_detail *cd = PDE_DATA(inode);
1591 return cache_open(inode, filp, cd);
1594 static int cache_release_procfs(struct inode *inode, struct file *filp)
1596 struct cache_detail *cd = PDE_DATA(inode);
1598 return cache_release(inode, filp, cd);
1601 static const struct proc_ops cache_channel_proc_ops = {
1602 .proc_lseek = no_llseek,
1603 .proc_read = cache_read_procfs,
1604 .proc_write = cache_write_procfs,
1605 .proc_poll = cache_poll_procfs,
1606 .proc_ioctl = cache_ioctl_procfs, /* for FIONREAD */
1607 .proc_open = cache_open_procfs,
1608 .proc_release = cache_release_procfs,
1611 static int content_open_procfs(struct inode *inode, struct file *filp)
1613 struct cache_detail *cd = PDE_DATA(inode);
1615 return content_open(inode, filp, cd);
1618 static int content_release_procfs(struct inode *inode, struct file *filp)
1620 struct cache_detail *cd = PDE_DATA(inode);
1622 return content_release(inode, filp, cd);
1625 static const struct proc_ops content_proc_ops = {
1626 .proc_open = content_open_procfs,
1627 .proc_read = seq_read,
1628 .proc_lseek = seq_lseek,
1629 .proc_release = content_release_procfs,
1632 static int open_flush_procfs(struct inode *inode, struct file *filp)
1634 struct cache_detail *cd = PDE_DATA(inode);
1636 return open_flush(inode, filp, cd);
1639 static int release_flush_procfs(struct inode *inode, struct file *filp)
1641 struct cache_detail *cd = PDE_DATA(inode);
1643 return release_flush(inode, filp, cd);
1646 static ssize_t read_flush_procfs(struct file *filp, char __user *buf,
1647 size_t count, loff_t *ppos)
1649 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1651 return read_flush(filp, buf, count, ppos, cd);
1654 static ssize_t write_flush_procfs(struct file *filp,
1655 const char __user *buf,
1656 size_t count, loff_t *ppos)
1658 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1660 return write_flush(filp, buf, count, ppos, cd);
1663 static const struct proc_ops cache_flush_proc_ops = {
1664 .proc_open = open_flush_procfs,
1665 .proc_read = read_flush_procfs,
1666 .proc_write = write_flush_procfs,
1667 .proc_release = release_flush_procfs,
1668 .proc_lseek = no_llseek,
1671 static void remove_cache_proc_entries(struct cache_detail *cd)
1674 proc_remove(cd->procfs);
1679 #ifdef CONFIG_PROC_FS
1680 static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1682 struct proc_dir_entry *p;
1683 struct sunrpc_net *sn;
1685 sn = net_generic(net, sunrpc_net_id);
1686 cd->procfs = proc_mkdir(cd->name, sn->proc_net_rpc);
1687 if (cd->procfs == NULL)
1690 p = proc_create_data("flush", S_IFREG | 0600,
1691 cd->procfs, &cache_flush_proc_ops, cd);
1695 if (cd->cache_request || cd->cache_parse) {
1696 p = proc_create_data("channel", S_IFREG | 0600, cd->procfs,
1697 &cache_channel_proc_ops, cd);
1701 if (cd->cache_show) {
1702 p = proc_create_data("content", S_IFREG | 0400, cd->procfs,
1703 &content_proc_ops, cd);
1709 remove_cache_proc_entries(cd);
1712 #else /* CONFIG_PROC_FS */
1713 static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1719 void __init cache_initialize(void)
1721 INIT_DEFERRABLE_WORK(&cache_cleaner, do_cache_clean);
1724 int cache_register_net(struct cache_detail *cd, struct net *net)
1728 sunrpc_init_cache_detail(cd);
1729 ret = create_cache_proc_entries(cd, net);
1731 sunrpc_destroy_cache_detail(cd);
1734 EXPORT_SYMBOL_GPL(cache_register_net);
1736 void cache_unregister_net(struct cache_detail *cd, struct net *net)
1738 remove_cache_proc_entries(cd);
1739 sunrpc_destroy_cache_detail(cd);
1741 EXPORT_SYMBOL_GPL(cache_unregister_net);
1743 struct cache_detail *cache_create_net(const struct cache_detail *tmpl, struct net *net)
1745 struct cache_detail *cd;
1748 cd = kmemdup(tmpl, sizeof(struct cache_detail), GFP_KERNEL);
1750 return ERR_PTR(-ENOMEM);
1752 cd->hash_table = kcalloc(cd->hash_size, sizeof(struct hlist_head),
1754 if (cd->hash_table == NULL) {
1756 return ERR_PTR(-ENOMEM);
1759 for (i = 0; i < cd->hash_size; i++)
1760 INIT_HLIST_HEAD(&cd->hash_table[i]);
1764 EXPORT_SYMBOL_GPL(cache_create_net);
1766 void cache_destroy_net(struct cache_detail *cd, struct net *net)
1768 kfree(cd->hash_table);
1771 EXPORT_SYMBOL_GPL(cache_destroy_net);
1773 static ssize_t cache_read_pipefs(struct file *filp, char __user *buf,
1774 size_t count, loff_t *ppos)
1776 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1778 return cache_read(filp, buf, count, ppos, cd);
1781 static ssize_t cache_write_pipefs(struct file *filp, const char __user *buf,
1782 size_t count, loff_t *ppos)
1784 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1786 return cache_write(filp, buf, count, ppos, cd);
1789 static __poll_t cache_poll_pipefs(struct file *filp, poll_table *wait)
1791 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1793 return cache_poll(filp, wait, cd);
1796 static long cache_ioctl_pipefs(struct file *filp,
1797 unsigned int cmd, unsigned long arg)
1799 struct inode *inode = file_inode(filp);
1800 struct cache_detail *cd = RPC_I(inode)->private;
1802 return cache_ioctl(inode, filp, cmd, arg, cd);
1805 static int cache_open_pipefs(struct inode *inode, struct file *filp)
1807 struct cache_detail *cd = RPC_I(inode)->private;
1809 return cache_open(inode, filp, cd);
1812 static int cache_release_pipefs(struct inode *inode, struct file *filp)
1814 struct cache_detail *cd = RPC_I(inode)->private;
1816 return cache_release(inode, filp, cd);
1819 const struct file_operations cache_file_operations_pipefs = {
1820 .owner = THIS_MODULE,
1821 .llseek = no_llseek,
1822 .read = cache_read_pipefs,
1823 .write = cache_write_pipefs,
1824 .poll = cache_poll_pipefs,
1825 .unlocked_ioctl = cache_ioctl_pipefs, /* for FIONREAD */
1826 .open = cache_open_pipefs,
1827 .release = cache_release_pipefs,
1830 static int content_open_pipefs(struct inode *inode, struct file *filp)
1832 struct cache_detail *cd = RPC_I(inode)->private;
1834 return content_open(inode, filp, cd);
1837 static int content_release_pipefs(struct inode *inode, struct file *filp)
1839 struct cache_detail *cd = RPC_I(inode)->private;
1841 return content_release(inode, filp, cd);
1844 const struct file_operations content_file_operations_pipefs = {
1845 .open = content_open_pipefs,
1847 .llseek = seq_lseek,
1848 .release = content_release_pipefs,
1851 static int open_flush_pipefs(struct inode *inode, struct file *filp)
1853 struct cache_detail *cd = RPC_I(inode)->private;
1855 return open_flush(inode, filp, cd);
1858 static int release_flush_pipefs(struct inode *inode, struct file *filp)
1860 struct cache_detail *cd = RPC_I(inode)->private;
1862 return release_flush(inode, filp, cd);
1865 static ssize_t read_flush_pipefs(struct file *filp, char __user *buf,
1866 size_t count, loff_t *ppos)
1868 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1870 return read_flush(filp, buf, count, ppos, cd);
1873 static ssize_t write_flush_pipefs(struct file *filp,
1874 const char __user *buf,
1875 size_t count, loff_t *ppos)
1877 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1879 return write_flush(filp, buf, count, ppos, cd);
1882 const struct file_operations cache_flush_operations_pipefs = {
1883 .open = open_flush_pipefs,
1884 .read = read_flush_pipefs,
1885 .write = write_flush_pipefs,
1886 .release = release_flush_pipefs,
1887 .llseek = no_llseek,
1890 int sunrpc_cache_register_pipefs(struct dentry *parent,
1891 const char *name, umode_t umode,
1892 struct cache_detail *cd)
1894 struct dentry *dir = rpc_create_cache_dir(parent, name, umode, cd);
1896 return PTR_ERR(dir);
1900 EXPORT_SYMBOL_GPL(sunrpc_cache_register_pipefs);
1902 void sunrpc_cache_unregister_pipefs(struct cache_detail *cd)
1905 rpc_remove_cache_dir(cd->pipefs);
1909 EXPORT_SYMBOL_GPL(sunrpc_cache_unregister_pipefs);
1911 void sunrpc_cache_unhash(struct cache_detail *cd, struct cache_head *h)
1913 spin_lock(&cd->hash_lock);
1914 if (!hlist_unhashed(&h->cache_list)){
1915 sunrpc_begin_cache_remove_entry(h, cd);
1916 spin_unlock(&cd->hash_lock);
1917 sunrpc_end_cache_remove_entry(h, cd);
1919 spin_unlock(&cd->hash_lock);
1921 EXPORT_SYMBOL_GPL(sunrpc_cache_unhash);