xref: /openbmc/linux/net/sunrpc/cache.c (revision 8032bf12)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * net/sunrpc/cache.c
4  *
5  * Generic code for various authentication-related caches
6  * used by sunrpc clients and servers.
7  *
8  * Copyright (C) 2002 Neil Brown <neilb@cse.unsw.edu.au>
9  */
10 
11 #include <linux/types.h>
12 #include <linux/fs.h>
13 #include <linux/file.h>
14 #include <linux/slab.h>
15 #include <linux/signal.h>
16 #include <linux/sched.h>
17 #include <linux/kmod.h>
18 #include <linux/list.h>
19 #include <linux/module.h>
20 #include <linux/ctype.h>
21 #include <linux/string_helpers.h>
22 #include <linux/uaccess.h>
23 #include <linux/poll.h>
24 #include <linux/seq_file.h>
25 #include <linux/proc_fs.h>
26 #include <linux/net.h>
27 #include <linux/workqueue.h>
28 #include <linux/mutex.h>
29 #include <linux/pagemap.h>
30 #include <asm/ioctls.h>
31 #include <linux/sunrpc/types.h>
32 #include <linux/sunrpc/cache.h>
33 #include <linux/sunrpc/stats.h>
34 #include <linux/sunrpc/rpc_pipe_fs.h>
35 #include <trace/events/sunrpc.h>
36 
37 #include "netns.h"
38 #include "fail.h"
39 
40 #define	 RPCDBG_FACILITY RPCDBG_CACHE
41 
42 static bool cache_defer_req(struct cache_req *req, struct cache_head *item);
43 static void cache_revisit_request(struct cache_head *item);
44 
cache_init(struct cache_head * h,struct cache_detail * detail)45 static void cache_init(struct cache_head *h, struct cache_detail *detail)
46 {
47 	time64_t now = seconds_since_boot();
48 	INIT_HLIST_NODE(&h->cache_list);
49 	h->flags = 0;
50 	kref_init(&h->ref);
51 	h->expiry_time = now + CACHE_NEW_EXPIRY;
52 	if (now <= detail->flush_time)
53 		/* ensure it isn't already expired */
54 		now = detail->flush_time + 1;
55 	h->last_refresh = now;
56 }
57 
58 static void cache_fresh_unlocked(struct cache_head *head,
59 				struct cache_detail *detail);
60 
sunrpc_cache_find_rcu(struct cache_detail * detail,struct cache_head * key,int hash)61 static struct cache_head *sunrpc_cache_find_rcu(struct cache_detail *detail,
62 						struct cache_head *key,
63 						int hash)
64 {
65 	struct hlist_head *head = &detail->hash_table[hash];
66 	struct cache_head *tmp;
67 
68 	rcu_read_lock();
69 	hlist_for_each_entry_rcu(tmp, head, cache_list) {
70 		if (!detail->match(tmp, key))
71 			continue;
72 		if (test_bit(CACHE_VALID, &tmp->flags) &&
73 		    cache_is_expired(detail, tmp))
74 			continue;
75 		tmp = cache_get_rcu(tmp);
76 		rcu_read_unlock();
77 		return tmp;
78 	}
79 	rcu_read_unlock();
80 	return NULL;
81 }
82 
sunrpc_begin_cache_remove_entry(struct cache_head * ch,struct cache_detail * cd)83 static void sunrpc_begin_cache_remove_entry(struct cache_head *ch,
84 					    struct cache_detail *cd)
85 {
86 	/* Must be called under cd->hash_lock */
87 	hlist_del_init_rcu(&ch->cache_list);
88 	set_bit(CACHE_CLEANED, &ch->flags);
89 	cd->entries --;
90 }
91 
sunrpc_end_cache_remove_entry(struct cache_head * ch,struct cache_detail * cd)92 static void sunrpc_end_cache_remove_entry(struct cache_head *ch,
93 					  struct cache_detail *cd)
94 {
95 	cache_fresh_unlocked(ch, cd);
96 	cache_put(ch, cd);
97 }
98 
sunrpc_cache_add_entry(struct cache_detail * detail,struct cache_head * key,int hash)99 static struct cache_head *sunrpc_cache_add_entry(struct cache_detail *detail,
100 						 struct cache_head *key,
101 						 int hash)
102 {
103 	struct cache_head *new, *tmp, *freeme = NULL;
104 	struct hlist_head *head = &detail->hash_table[hash];
105 
106 	new = detail->alloc();
107 	if (!new)
108 		return NULL;
109 	/* must fully initialise 'new', else
110 	 * we might get lose if we need to
111 	 * cache_put it soon.
112 	 */
113 	cache_init(new, detail);
114 	detail->init(new, key);
115 
116 	spin_lock(&detail->hash_lock);
117 
118 	/* check if entry appeared while we slept */
119 	hlist_for_each_entry_rcu(tmp, head, cache_list,
120 				 lockdep_is_held(&detail->hash_lock)) {
121 		if (!detail->match(tmp, key))
122 			continue;
123 		if (test_bit(CACHE_VALID, &tmp->flags) &&
124 		    cache_is_expired(detail, tmp)) {
125 			sunrpc_begin_cache_remove_entry(tmp, detail);
126 			trace_cache_entry_expired(detail, tmp);
127 			freeme = tmp;
128 			break;
129 		}
130 		cache_get(tmp);
131 		spin_unlock(&detail->hash_lock);
132 		cache_put(new, detail);
133 		return tmp;
134 	}
135 
136 	hlist_add_head_rcu(&new->cache_list, head);
137 	detail->entries++;
138 	cache_get(new);
139 	spin_unlock(&detail->hash_lock);
140 
141 	if (freeme)
142 		sunrpc_end_cache_remove_entry(freeme, detail);
143 	return new;
144 }
145 
sunrpc_cache_lookup_rcu(struct cache_detail * detail,struct cache_head * key,int hash)146 struct cache_head *sunrpc_cache_lookup_rcu(struct cache_detail *detail,
147 					   struct cache_head *key, int hash)
148 {
149 	struct cache_head *ret;
150 
151 	ret = sunrpc_cache_find_rcu(detail, key, hash);
152 	if (ret)
153 		return ret;
154 	/* Didn't find anything, insert an empty entry */
155 	return sunrpc_cache_add_entry(detail, key, hash);
156 }
157 EXPORT_SYMBOL_GPL(sunrpc_cache_lookup_rcu);
158 
159 static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch);
160 
cache_fresh_locked(struct cache_head * head,time64_t expiry,struct cache_detail * detail)161 static void cache_fresh_locked(struct cache_head *head, time64_t expiry,
162 			       struct cache_detail *detail)
163 {
164 	time64_t now = seconds_since_boot();
165 	if (now <= detail->flush_time)
166 		/* ensure it isn't immediately treated as expired */
167 		now = detail->flush_time + 1;
168 	head->expiry_time = expiry;
169 	head->last_refresh = now;
170 	smp_wmb(); /* paired with smp_rmb() in cache_is_valid() */
171 	set_bit(CACHE_VALID, &head->flags);
172 }
173 
cache_fresh_unlocked(struct cache_head * head,struct cache_detail * detail)174 static void cache_fresh_unlocked(struct cache_head *head,
175 				 struct cache_detail *detail)
176 {
177 	if (test_and_clear_bit(CACHE_PENDING, &head->flags)) {
178 		cache_revisit_request(head);
179 		cache_dequeue(detail, head);
180 	}
181 }
182 
cache_make_negative(struct cache_detail * detail,struct cache_head * h)183 static void cache_make_negative(struct cache_detail *detail,
184 				struct cache_head *h)
185 {
186 	set_bit(CACHE_NEGATIVE, &h->flags);
187 	trace_cache_entry_make_negative(detail, h);
188 }
189 
cache_entry_update(struct cache_detail * detail,struct cache_head * h,struct cache_head * new)190 static void cache_entry_update(struct cache_detail *detail,
191 			       struct cache_head *h,
192 			       struct cache_head *new)
193 {
194 	if (!test_bit(CACHE_NEGATIVE, &new->flags)) {
195 		detail->update(h, new);
196 		trace_cache_entry_update(detail, h);
197 	} else {
198 		cache_make_negative(detail, h);
199 	}
200 }
201 
sunrpc_cache_update(struct cache_detail * detail,struct cache_head * new,struct cache_head * old,int hash)202 struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
203 				       struct cache_head *new, struct cache_head *old, int hash)
204 {
205 	/* The 'old' entry is to be replaced by 'new'.
206 	 * If 'old' is not VALID, we update it directly,
207 	 * otherwise we need to replace it
208 	 */
209 	struct cache_head *tmp;
210 
211 	if (!test_bit(CACHE_VALID, &old->flags)) {
212 		spin_lock(&detail->hash_lock);
213 		if (!test_bit(CACHE_VALID, &old->flags)) {
214 			cache_entry_update(detail, old, new);
215 			cache_fresh_locked(old, new->expiry_time, detail);
216 			spin_unlock(&detail->hash_lock);
217 			cache_fresh_unlocked(old, detail);
218 			return old;
219 		}
220 		spin_unlock(&detail->hash_lock);
221 	}
222 	/* We need to insert a new entry */
223 	tmp = detail->alloc();
224 	if (!tmp) {
225 		cache_put(old, detail);
226 		return NULL;
227 	}
228 	cache_init(tmp, detail);
229 	detail->init(tmp, old);
230 
231 	spin_lock(&detail->hash_lock);
232 	cache_entry_update(detail, tmp, new);
233 	hlist_add_head(&tmp->cache_list, &detail->hash_table[hash]);
234 	detail->entries++;
235 	cache_get(tmp);
236 	cache_fresh_locked(tmp, new->expiry_time, detail);
237 	cache_fresh_locked(old, 0, detail);
238 	spin_unlock(&detail->hash_lock);
239 	cache_fresh_unlocked(tmp, detail);
240 	cache_fresh_unlocked(old, detail);
241 	cache_put(old, detail);
242 	return tmp;
243 }
244 EXPORT_SYMBOL_GPL(sunrpc_cache_update);
245 
cache_is_valid(struct cache_head * h)246 static inline int cache_is_valid(struct cache_head *h)
247 {
248 	if (!test_bit(CACHE_VALID, &h->flags))
249 		return -EAGAIN;
250 	else {
251 		/* entry is valid */
252 		if (test_bit(CACHE_NEGATIVE, &h->flags))
253 			return -ENOENT;
254 		else {
255 			/*
256 			 * In combination with write barrier in
257 			 * sunrpc_cache_update, ensures that anyone
258 			 * using the cache entry after this sees the
259 			 * updated contents:
260 			 */
261 			smp_rmb();
262 			return 0;
263 		}
264 	}
265 }
266 
try_to_negate_entry(struct cache_detail * detail,struct cache_head * h)267 static int try_to_negate_entry(struct cache_detail *detail, struct cache_head *h)
268 {
269 	int rv;
270 
271 	spin_lock(&detail->hash_lock);
272 	rv = cache_is_valid(h);
273 	if (rv == -EAGAIN) {
274 		cache_make_negative(detail, h);
275 		cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY,
276 				   detail);
277 		rv = -ENOENT;
278 	}
279 	spin_unlock(&detail->hash_lock);
280 	cache_fresh_unlocked(h, detail);
281 	return rv;
282 }
283 
284 /*
285  * This is the generic cache management routine for all
286  * the authentication caches.
287  * It checks the currency of a cache item and will (later)
288  * initiate an upcall to fill it if needed.
289  *
290  *
291  * Returns 0 if the cache_head can be used, or cache_puts it and returns
292  * -EAGAIN if upcall is pending and request has been queued
293  * -ETIMEDOUT if upcall failed or request could not be queue or
294  *           upcall completed but item is still invalid (implying that
295  *           the cache item has been replaced with a newer one).
296  * -ENOENT if cache entry was negative
297  */
cache_check(struct cache_detail * detail,struct cache_head * h,struct cache_req * rqstp)298 int cache_check(struct cache_detail *detail,
299 		    struct cache_head *h, struct cache_req *rqstp)
300 {
301 	int rv;
302 	time64_t refresh_age, age;
303 
304 	/* First decide return status as best we can */
305 	rv = cache_is_valid(h);
306 
307 	/* now see if we want to start an upcall */
308 	refresh_age = (h->expiry_time - h->last_refresh);
309 	age = seconds_since_boot() - h->last_refresh;
310 
311 	if (rqstp == NULL) {
312 		if (rv == -EAGAIN)
313 			rv = -ENOENT;
314 	} else if (rv == -EAGAIN ||
315 		   (h->expiry_time != 0 && age > refresh_age/2)) {
316 		dprintk("RPC:       Want update, refage=%lld, age=%lld\n",
317 				refresh_age, age);
318 		switch (detail->cache_upcall(detail, h)) {
319 		case -EINVAL:
320 			rv = try_to_negate_entry(detail, h);
321 			break;
322 		case -EAGAIN:
323 			cache_fresh_unlocked(h, detail);
324 			break;
325 		}
326 	}
327 
328 	if (rv == -EAGAIN) {
329 		if (!cache_defer_req(rqstp, h)) {
330 			/*
331 			 * Request was not deferred; handle it as best
332 			 * we can ourselves:
333 			 */
334 			rv = cache_is_valid(h);
335 			if (rv == -EAGAIN)
336 				rv = -ETIMEDOUT;
337 		}
338 	}
339 	if (rv)
340 		cache_put(h, detail);
341 	return rv;
342 }
343 EXPORT_SYMBOL_GPL(cache_check);
344 
345 /*
346  * caches need to be periodically cleaned.
347  * For this we maintain a list of cache_detail and
348  * a current pointer into that list and into the table
349  * for that entry.
350  *
351  * Each time cache_clean is called it finds the next non-empty entry
352  * in the current table and walks the list in that entry
353  * looking for entries that can be removed.
354  *
355  * An entry gets removed if:
356  * - The expiry is before current time
357  * - The last_refresh time is before the flush_time for that cache
358  *
359  * later we might drop old entries with non-NEVER expiry if that table
360  * is getting 'full' for some definition of 'full'
361  *
362  * The question of "how often to scan a table" is an interesting one
363  * and is answered in part by the use of the "nextcheck" field in the
364  * cache_detail.
365  * When a scan of a table begins, the nextcheck field is set to a time
366  * that is well into the future.
367  * While scanning, if an expiry time is found that is earlier than the
368  * current nextcheck time, nextcheck is set to that expiry time.
369  * If the flush_time is ever set to a time earlier than the nextcheck
370  * time, the nextcheck time is then set to that flush_time.
371  *
372  * A table is then only scanned if the current time is at least
373  * the nextcheck time.
374  *
375  */
376 
377 static LIST_HEAD(cache_list);
378 static DEFINE_SPINLOCK(cache_list_lock);
379 static struct cache_detail *current_detail;
380 static int current_index;
381 
382 static void do_cache_clean(struct work_struct *work);
383 static struct delayed_work cache_cleaner;
384 
sunrpc_init_cache_detail(struct cache_detail * cd)385 void sunrpc_init_cache_detail(struct cache_detail *cd)
386 {
387 	spin_lock_init(&cd->hash_lock);
388 	INIT_LIST_HEAD(&cd->queue);
389 	spin_lock(&cache_list_lock);
390 	cd->nextcheck = 0;
391 	cd->entries = 0;
392 	atomic_set(&cd->writers, 0);
393 	cd->last_close = 0;
394 	cd->last_warn = -1;
395 	list_add(&cd->others, &cache_list);
396 	spin_unlock(&cache_list_lock);
397 
398 	/* start the cleaning process */
399 	queue_delayed_work(system_power_efficient_wq, &cache_cleaner, 0);
400 }
401 EXPORT_SYMBOL_GPL(sunrpc_init_cache_detail);
402 
sunrpc_destroy_cache_detail(struct cache_detail * cd)403 void sunrpc_destroy_cache_detail(struct cache_detail *cd)
404 {
405 	cache_purge(cd);
406 	spin_lock(&cache_list_lock);
407 	spin_lock(&cd->hash_lock);
408 	if (current_detail == cd)
409 		current_detail = NULL;
410 	list_del_init(&cd->others);
411 	spin_unlock(&cd->hash_lock);
412 	spin_unlock(&cache_list_lock);
413 	if (list_empty(&cache_list)) {
414 		/* module must be being unloaded so its safe to kill the worker */
415 		cancel_delayed_work_sync(&cache_cleaner);
416 	}
417 }
418 EXPORT_SYMBOL_GPL(sunrpc_destroy_cache_detail);
419 
420 /* clean cache tries to find something to clean
421  * and cleans it.
422  * It returns 1 if it cleaned something,
423  *            0 if it didn't find anything this time
424  *           -1 if it fell off the end of the list.
425  */
cache_clean(void)426 static int cache_clean(void)
427 {
428 	int rv = 0;
429 	struct list_head *next;
430 
431 	spin_lock(&cache_list_lock);
432 
433 	/* find a suitable table if we don't already have one */
434 	while (current_detail == NULL ||
435 	    current_index >= current_detail->hash_size) {
436 		if (current_detail)
437 			next = current_detail->others.next;
438 		else
439 			next = cache_list.next;
440 		if (next == &cache_list) {
441 			current_detail = NULL;
442 			spin_unlock(&cache_list_lock);
443 			return -1;
444 		}
445 		current_detail = list_entry(next, struct cache_detail, others);
446 		if (current_detail->nextcheck > seconds_since_boot())
447 			current_index = current_detail->hash_size;
448 		else {
449 			current_index = 0;
450 			current_detail->nextcheck = seconds_since_boot()+30*60;
451 		}
452 	}
453 
454 	/* find a non-empty bucket in the table */
455 	while (current_detail &&
456 	       current_index < current_detail->hash_size &&
457 	       hlist_empty(&current_detail->hash_table[current_index]))
458 		current_index++;
459 
460 	/* find a cleanable entry in the bucket and clean it, or set to next bucket */
461 
462 	if (current_detail && current_index < current_detail->hash_size) {
463 		struct cache_head *ch = NULL;
464 		struct cache_detail *d;
465 		struct hlist_head *head;
466 		struct hlist_node *tmp;
467 
468 		spin_lock(&current_detail->hash_lock);
469 
470 		/* Ok, now to clean this strand */
471 
472 		head = &current_detail->hash_table[current_index];
473 		hlist_for_each_entry_safe(ch, tmp, head, cache_list) {
474 			if (current_detail->nextcheck > ch->expiry_time)
475 				current_detail->nextcheck = ch->expiry_time+1;
476 			if (!cache_is_expired(current_detail, ch))
477 				continue;
478 
479 			sunrpc_begin_cache_remove_entry(ch, current_detail);
480 			trace_cache_entry_expired(current_detail, ch);
481 			rv = 1;
482 			break;
483 		}
484 
485 		spin_unlock(&current_detail->hash_lock);
486 		d = current_detail;
487 		if (!ch)
488 			current_index ++;
489 		spin_unlock(&cache_list_lock);
490 		if (ch)
491 			sunrpc_end_cache_remove_entry(ch, d);
492 	} else
493 		spin_unlock(&cache_list_lock);
494 
495 	return rv;
496 }
497 
498 /*
499  * We want to regularly clean the cache, so we need to schedule some work ...
500  */
do_cache_clean(struct work_struct * work)501 static void do_cache_clean(struct work_struct *work)
502 {
503 	int delay;
504 
505 	if (list_empty(&cache_list))
506 		return;
507 
508 	if (cache_clean() == -1)
509 		delay = round_jiffies_relative(30*HZ);
510 	else
511 		delay = 5;
512 
513 	queue_delayed_work(system_power_efficient_wq, &cache_cleaner, delay);
514 }
515 
516 
517 /*
518  * Clean all caches promptly.  This just calls cache_clean
519  * repeatedly until we are sure that every cache has had a chance to
520  * be fully cleaned
521  */
cache_flush(void)522 void cache_flush(void)
523 {
524 	while (cache_clean() != -1)
525 		cond_resched();
526 	while (cache_clean() != -1)
527 		cond_resched();
528 }
529 EXPORT_SYMBOL_GPL(cache_flush);
530 
cache_purge(struct cache_detail * detail)531 void cache_purge(struct cache_detail *detail)
532 {
533 	struct cache_head *ch = NULL;
534 	struct hlist_head *head = NULL;
535 	int i = 0;
536 
537 	spin_lock(&detail->hash_lock);
538 	if (!detail->entries) {
539 		spin_unlock(&detail->hash_lock);
540 		return;
541 	}
542 
543 	dprintk("RPC: %d entries in %s cache\n", detail->entries, detail->name);
544 	for (i = 0; i < detail->hash_size; i++) {
545 		head = &detail->hash_table[i];
546 		while (!hlist_empty(head)) {
547 			ch = hlist_entry(head->first, struct cache_head,
548 					 cache_list);
549 			sunrpc_begin_cache_remove_entry(ch, detail);
550 			spin_unlock(&detail->hash_lock);
551 			sunrpc_end_cache_remove_entry(ch, detail);
552 			spin_lock(&detail->hash_lock);
553 		}
554 	}
555 	spin_unlock(&detail->hash_lock);
556 }
557 EXPORT_SYMBOL_GPL(cache_purge);
558 
559 
560 /*
561  * Deferral and Revisiting of Requests.
562  *
563  * If a cache lookup finds a pending entry, we
564  * need to defer the request and revisit it later.
565  * All deferred requests are stored in a hash table,
566  * indexed by "struct cache_head *".
567  * As it may be wasteful to store a whole request
568  * structure, we allow the request to provide a
569  * deferred form, which must contain a
570  * 'struct cache_deferred_req'
571  * This cache_deferred_req contains a method to allow
572  * it to be revisited when cache info is available
573  */
574 
575 #define	DFR_HASHSIZE	(PAGE_SIZE/sizeof(struct list_head))
576 #define	DFR_HASH(item)	((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE)
577 
578 #define	DFR_MAX	300	/* ??? */
579 
580 static DEFINE_SPINLOCK(cache_defer_lock);
581 static LIST_HEAD(cache_defer_list);
582 static struct hlist_head cache_defer_hash[DFR_HASHSIZE];
583 static int cache_defer_cnt;
584 
__unhash_deferred_req(struct cache_deferred_req * dreq)585 static void __unhash_deferred_req(struct cache_deferred_req *dreq)
586 {
587 	hlist_del_init(&dreq->hash);
588 	if (!list_empty(&dreq->recent)) {
589 		list_del_init(&dreq->recent);
590 		cache_defer_cnt--;
591 	}
592 }
593 
__hash_deferred_req(struct cache_deferred_req * dreq,struct cache_head * item)594 static void __hash_deferred_req(struct cache_deferred_req *dreq, struct cache_head *item)
595 {
596 	int hash = DFR_HASH(item);
597 
598 	INIT_LIST_HEAD(&dreq->recent);
599 	hlist_add_head(&dreq->hash, &cache_defer_hash[hash]);
600 }
601 
setup_deferral(struct cache_deferred_req * dreq,struct cache_head * item,int count_me)602 static void setup_deferral(struct cache_deferred_req *dreq,
603 			   struct cache_head *item,
604 			   int count_me)
605 {
606 
607 	dreq->item = item;
608 
609 	spin_lock(&cache_defer_lock);
610 
611 	__hash_deferred_req(dreq, item);
612 
613 	if (count_me) {
614 		cache_defer_cnt++;
615 		list_add(&dreq->recent, &cache_defer_list);
616 	}
617 
618 	spin_unlock(&cache_defer_lock);
619 
620 }
621 
622 struct thread_deferred_req {
623 	struct cache_deferred_req handle;
624 	struct completion completion;
625 };
626 
cache_restart_thread(struct cache_deferred_req * dreq,int too_many)627 static void cache_restart_thread(struct cache_deferred_req *dreq, int too_many)
628 {
629 	struct thread_deferred_req *dr =
630 		container_of(dreq, struct thread_deferred_req, handle);
631 	complete(&dr->completion);
632 }
633 
cache_wait_req(struct cache_req * req,struct cache_head * item)634 static void cache_wait_req(struct cache_req *req, struct cache_head *item)
635 {
636 	struct thread_deferred_req sleeper;
637 	struct cache_deferred_req *dreq = &sleeper.handle;
638 
639 	sleeper.completion = COMPLETION_INITIALIZER_ONSTACK(sleeper.completion);
640 	dreq->revisit = cache_restart_thread;
641 
642 	setup_deferral(dreq, item, 0);
643 
644 	if (!test_bit(CACHE_PENDING, &item->flags) ||
645 	    wait_for_completion_interruptible_timeout(
646 		    &sleeper.completion, req->thread_wait) <= 0) {
647 		/* The completion wasn't completed, so we need
648 		 * to clean up
649 		 */
650 		spin_lock(&cache_defer_lock);
651 		if (!hlist_unhashed(&sleeper.handle.hash)) {
652 			__unhash_deferred_req(&sleeper.handle);
653 			spin_unlock(&cache_defer_lock);
654 		} else {
655 			/* cache_revisit_request already removed
656 			 * this from the hash table, but hasn't
657 			 * called ->revisit yet.  It will very soon
658 			 * and we need to wait for it.
659 			 */
660 			spin_unlock(&cache_defer_lock);
661 			wait_for_completion(&sleeper.completion);
662 		}
663 	}
664 }
665 
cache_limit_defers(void)666 static void cache_limit_defers(void)
667 {
668 	/* Make sure we haven't exceed the limit of allowed deferred
669 	 * requests.
670 	 */
671 	struct cache_deferred_req *discard = NULL;
672 
673 	if (cache_defer_cnt <= DFR_MAX)
674 		return;
675 
676 	spin_lock(&cache_defer_lock);
677 
678 	/* Consider removing either the first or the last */
679 	if (cache_defer_cnt > DFR_MAX) {
680 		if (get_random_u32_below(2))
681 			discard = list_entry(cache_defer_list.next,
682 					     struct cache_deferred_req, recent);
683 		else
684 			discard = list_entry(cache_defer_list.prev,
685 					     struct cache_deferred_req, recent);
686 		__unhash_deferred_req(discard);
687 	}
688 	spin_unlock(&cache_defer_lock);
689 	if (discard)
690 		discard->revisit(discard, 1);
691 }
692 
693 #if IS_ENABLED(CONFIG_FAIL_SUNRPC)
cache_defer_immediately(void)694 static inline bool cache_defer_immediately(void)
695 {
696 	return !fail_sunrpc.ignore_cache_wait &&
697 		should_fail(&fail_sunrpc.attr, 1);
698 }
699 #else
cache_defer_immediately(void)700 static inline bool cache_defer_immediately(void)
701 {
702 	return false;
703 }
704 #endif
705 
706 /* Return true if and only if a deferred request is queued. */
cache_defer_req(struct cache_req * req,struct cache_head * item)707 static bool cache_defer_req(struct cache_req *req, struct cache_head *item)
708 {
709 	struct cache_deferred_req *dreq;
710 
711 	if (!cache_defer_immediately()) {
712 		cache_wait_req(req, item);
713 		if (!test_bit(CACHE_PENDING, &item->flags))
714 			return false;
715 	}
716 
717 	dreq = req->defer(req);
718 	if (dreq == NULL)
719 		return false;
720 	setup_deferral(dreq, item, 1);
721 	if (!test_bit(CACHE_PENDING, &item->flags))
722 		/* Bit could have been cleared before we managed to
723 		 * set up the deferral, so need to revisit just in case
724 		 */
725 		cache_revisit_request(item);
726 
727 	cache_limit_defers();
728 	return true;
729 }
730 
cache_revisit_request(struct cache_head * item)731 static void cache_revisit_request(struct cache_head *item)
732 {
733 	struct cache_deferred_req *dreq;
734 	struct list_head pending;
735 	struct hlist_node *tmp;
736 	int hash = DFR_HASH(item);
737 
738 	INIT_LIST_HEAD(&pending);
739 	spin_lock(&cache_defer_lock);
740 
741 	hlist_for_each_entry_safe(dreq, tmp, &cache_defer_hash[hash], hash)
742 		if (dreq->item == item) {
743 			__unhash_deferred_req(dreq);
744 			list_add(&dreq->recent, &pending);
745 		}
746 
747 	spin_unlock(&cache_defer_lock);
748 
749 	while (!list_empty(&pending)) {
750 		dreq = list_entry(pending.next, struct cache_deferred_req, recent);
751 		list_del_init(&dreq->recent);
752 		dreq->revisit(dreq, 0);
753 	}
754 }
755 
cache_clean_deferred(void * owner)756 void cache_clean_deferred(void *owner)
757 {
758 	struct cache_deferred_req *dreq, *tmp;
759 	struct list_head pending;
760 
761 
762 	INIT_LIST_HEAD(&pending);
763 	spin_lock(&cache_defer_lock);
764 
765 	list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) {
766 		if (dreq->owner == owner) {
767 			__unhash_deferred_req(dreq);
768 			list_add(&dreq->recent, &pending);
769 		}
770 	}
771 	spin_unlock(&cache_defer_lock);
772 
773 	while (!list_empty(&pending)) {
774 		dreq = list_entry(pending.next, struct cache_deferred_req, recent);
775 		list_del_init(&dreq->recent);
776 		dreq->revisit(dreq, 1);
777 	}
778 }
779 
780 /*
781  * communicate with user-space
782  *
783  * We have a magic /proc file - /proc/net/rpc/<cachename>/channel.
784  * On read, you get a full request, or block.
785  * On write, an update request is processed.
786  * Poll works if anything to read, and always allows write.
787  *
788  * Implemented by linked list of requests.  Each open file has
789  * a ->private that also exists in this list.  New requests are added
790  * to the end and may wakeup and preceding readers.
791  * New readers are added to the head.  If, on read, an item is found with
792  * CACHE_UPCALLING clear, we free it from the list.
793  *
794  */
795 
796 static DEFINE_SPINLOCK(queue_lock);
797 
798 struct cache_queue {
799 	struct list_head	list;
800 	int			reader;	/* if 0, then request */
801 };
802 struct cache_request {
803 	struct cache_queue	q;
804 	struct cache_head	*item;
805 	char			* buf;
806 	int			len;
807 	int			readers;
808 };
809 struct cache_reader {
810 	struct cache_queue	q;
811 	int			offset;	/* if non-0, we have a refcnt on next request */
812 };
813 
cache_request(struct cache_detail * detail,struct cache_request * crq)814 static int cache_request(struct cache_detail *detail,
815 			       struct cache_request *crq)
816 {
817 	char *bp = crq->buf;
818 	int len = PAGE_SIZE;
819 
820 	detail->cache_request(detail, crq->item, &bp, &len);
821 	if (len < 0)
822 		return -E2BIG;
823 	return PAGE_SIZE - len;
824 }
825 
cache_read(struct file * filp,char __user * buf,size_t count,loff_t * ppos,struct cache_detail * cd)826 static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
827 			  loff_t *ppos, struct cache_detail *cd)
828 {
829 	struct cache_reader *rp = filp->private_data;
830 	struct cache_request *rq;
831 	struct inode *inode = file_inode(filp);
832 	int err;
833 
834 	if (count == 0)
835 		return 0;
836 
837 	inode_lock(inode); /* protect against multiple concurrent
838 			      * readers on this file */
839  again:
840 	spin_lock(&queue_lock);
841 	/* need to find next request */
842 	while (rp->q.list.next != &cd->queue &&
843 	       list_entry(rp->q.list.next, struct cache_queue, list)
844 	       ->reader) {
845 		struct list_head *next = rp->q.list.next;
846 		list_move(&rp->q.list, next);
847 	}
848 	if (rp->q.list.next == &cd->queue) {
849 		spin_unlock(&queue_lock);
850 		inode_unlock(inode);
851 		WARN_ON_ONCE(rp->offset);
852 		return 0;
853 	}
854 	rq = container_of(rp->q.list.next, struct cache_request, q.list);
855 	WARN_ON_ONCE(rq->q.reader);
856 	if (rp->offset == 0)
857 		rq->readers++;
858 	spin_unlock(&queue_lock);
859 
860 	if (rq->len == 0) {
861 		err = cache_request(cd, rq);
862 		if (err < 0)
863 			goto out;
864 		rq->len = err;
865 	}
866 
867 	if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
868 		err = -EAGAIN;
869 		spin_lock(&queue_lock);
870 		list_move(&rp->q.list, &rq->q.list);
871 		spin_unlock(&queue_lock);
872 	} else {
873 		if (rp->offset + count > rq->len)
874 			count = rq->len - rp->offset;
875 		err = -EFAULT;
876 		if (copy_to_user(buf, rq->buf + rp->offset, count))
877 			goto out;
878 		rp->offset += count;
879 		if (rp->offset >= rq->len) {
880 			rp->offset = 0;
881 			spin_lock(&queue_lock);
882 			list_move(&rp->q.list, &rq->q.list);
883 			spin_unlock(&queue_lock);
884 		}
885 		err = 0;
886 	}
887  out:
888 	if (rp->offset == 0) {
889 		/* need to release rq */
890 		spin_lock(&queue_lock);
891 		rq->readers--;
892 		if (rq->readers == 0 &&
893 		    !test_bit(CACHE_PENDING, &rq->item->flags)) {
894 			list_del(&rq->q.list);
895 			spin_unlock(&queue_lock);
896 			cache_put(rq->item, cd);
897 			kfree(rq->buf);
898 			kfree(rq);
899 		} else
900 			spin_unlock(&queue_lock);
901 	}
902 	if (err == -EAGAIN)
903 		goto again;
904 	inode_unlock(inode);
905 	return err ? err :  count;
906 }
907 
cache_do_downcall(char * kaddr,const char __user * buf,size_t count,struct cache_detail * cd)908 static ssize_t cache_do_downcall(char *kaddr, const char __user *buf,
909 				 size_t count, struct cache_detail *cd)
910 {
911 	ssize_t ret;
912 
913 	if (count == 0)
914 		return -EINVAL;
915 	if (copy_from_user(kaddr, buf, count))
916 		return -EFAULT;
917 	kaddr[count] = '\0';
918 	ret = cd->cache_parse(cd, kaddr, count);
919 	if (!ret)
920 		ret = count;
921 	return ret;
922 }
923 
cache_downcall(struct address_space * mapping,const char __user * buf,size_t count,struct cache_detail * cd)924 static ssize_t cache_downcall(struct address_space *mapping,
925 			      const char __user *buf,
926 			      size_t count, struct cache_detail *cd)
927 {
928 	char *write_buf;
929 	ssize_t ret = -ENOMEM;
930 
931 	if (count >= 32768) { /* 32k is max userland buffer, lets check anyway */
932 		ret = -EINVAL;
933 		goto out;
934 	}
935 
936 	write_buf = kvmalloc(count + 1, GFP_KERNEL);
937 	if (!write_buf)
938 		goto out;
939 
940 	ret = cache_do_downcall(write_buf, buf, count, cd);
941 	kvfree(write_buf);
942 out:
943 	return ret;
944 }
945 
cache_write(struct file * filp,const char __user * buf,size_t count,loff_t * ppos,struct cache_detail * cd)946 static ssize_t cache_write(struct file *filp, const char __user *buf,
947 			   size_t count, loff_t *ppos,
948 			   struct cache_detail *cd)
949 {
950 	struct address_space *mapping = filp->f_mapping;
951 	struct inode *inode = file_inode(filp);
952 	ssize_t ret = -EINVAL;
953 
954 	if (!cd->cache_parse)
955 		goto out;
956 
957 	inode_lock(inode);
958 	ret = cache_downcall(mapping, buf, count, cd);
959 	inode_unlock(inode);
960 out:
961 	return ret;
962 }
963 
964 static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
965 
cache_poll(struct file * filp,poll_table * wait,struct cache_detail * cd)966 static __poll_t cache_poll(struct file *filp, poll_table *wait,
967 			       struct cache_detail *cd)
968 {
969 	__poll_t mask;
970 	struct cache_reader *rp = filp->private_data;
971 	struct cache_queue *cq;
972 
973 	poll_wait(filp, &queue_wait, wait);
974 
975 	/* alway allow write */
976 	mask = EPOLLOUT | EPOLLWRNORM;
977 
978 	if (!rp)
979 		return mask;
980 
981 	spin_lock(&queue_lock);
982 
983 	for (cq= &rp->q; &cq->list != &cd->queue;
984 	     cq = list_entry(cq->list.next, struct cache_queue, list))
985 		if (!cq->reader) {
986 			mask |= EPOLLIN | EPOLLRDNORM;
987 			break;
988 		}
989 	spin_unlock(&queue_lock);
990 	return mask;
991 }
992 
cache_ioctl(struct inode * ino,struct file * filp,unsigned int cmd,unsigned long arg,struct cache_detail * cd)993 static int cache_ioctl(struct inode *ino, struct file *filp,
994 		       unsigned int cmd, unsigned long arg,
995 		       struct cache_detail *cd)
996 {
997 	int len = 0;
998 	struct cache_reader *rp = filp->private_data;
999 	struct cache_queue *cq;
1000 
1001 	if (cmd != FIONREAD || !rp)
1002 		return -EINVAL;
1003 
1004 	spin_lock(&queue_lock);
1005 
1006 	/* only find the length remaining in current request,
1007 	 * or the length of the next request
1008 	 */
1009 	for (cq= &rp->q; &cq->list != &cd->queue;
1010 	     cq = list_entry(cq->list.next, struct cache_queue, list))
1011 		if (!cq->reader) {
1012 			struct cache_request *cr =
1013 				container_of(cq, struct cache_request, q);
1014 			len = cr->len - rp->offset;
1015 			break;
1016 		}
1017 	spin_unlock(&queue_lock);
1018 
1019 	return put_user(len, (int __user *)arg);
1020 }
1021 
cache_open(struct inode * inode,struct file * filp,struct cache_detail * cd)1022 static int cache_open(struct inode *inode, struct file *filp,
1023 		      struct cache_detail *cd)
1024 {
1025 	struct cache_reader *rp = NULL;
1026 
1027 	if (!cd || !try_module_get(cd->owner))
1028 		return -EACCES;
1029 	nonseekable_open(inode, filp);
1030 	if (filp->f_mode & FMODE_READ) {
1031 		rp = kmalloc(sizeof(*rp), GFP_KERNEL);
1032 		if (!rp) {
1033 			module_put(cd->owner);
1034 			return -ENOMEM;
1035 		}
1036 		rp->offset = 0;
1037 		rp->q.reader = 1;
1038 
1039 		spin_lock(&queue_lock);
1040 		list_add(&rp->q.list, &cd->queue);
1041 		spin_unlock(&queue_lock);
1042 	}
1043 	if (filp->f_mode & FMODE_WRITE)
1044 		atomic_inc(&cd->writers);
1045 	filp->private_data = rp;
1046 	return 0;
1047 }
1048 
cache_release(struct inode * inode,struct file * filp,struct cache_detail * cd)1049 static int cache_release(struct inode *inode, struct file *filp,
1050 			 struct cache_detail *cd)
1051 {
1052 	struct cache_reader *rp = filp->private_data;
1053 
1054 	if (rp) {
1055 		spin_lock(&queue_lock);
1056 		if (rp->offset) {
1057 			struct cache_queue *cq;
1058 			for (cq= &rp->q; &cq->list != &cd->queue;
1059 			     cq = list_entry(cq->list.next, struct cache_queue, list))
1060 				if (!cq->reader) {
1061 					container_of(cq, struct cache_request, q)
1062 						->readers--;
1063 					break;
1064 				}
1065 			rp->offset = 0;
1066 		}
1067 		list_del(&rp->q.list);
1068 		spin_unlock(&queue_lock);
1069 
1070 		filp->private_data = NULL;
1071 		kfree(rp);
1072 
1073 	}
1074 	if (filp->f_mode & FMODE_WRITE) {
1075 		atomic_dec(&cd->writers);
1076 		cd->last_close = seconds_since_boot();
1077 	}
1078 	module_put(cd->owner);
1079 	return 0;
1080 }
1081 
1082 
1083 
cache_dequeue(struct cache_detail * detail,struct cache_head * ch)1084 static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch)
1085 {
1086 	struct cache_queue *cq, *tmp;
1087 	struct cache_request *cr;
1088 	struct list_head dequeued;
1089 
1090 	INIT_LIST_HEAD(&dequeued);
1091 	spin_lock(&queue_lock);
1092 	list_for_each_entry_safe(cq, tmp, &detail->queue, list)
1093 		if (!cq->reader) {
1094 			cr = container_of(cq, struct cache_request, q);
1095 			if (cr->item != ch)
1096 				continue;
1097 			if (test_bit(CACHE_PENDING, &ch->flags))
1098 				/* Lost a race and it is pending again */
1099 				break;
1100 			if (cr->readers != 0)
1101 				continue;
1102 			list_move(&cr->q.list, &dequeued);
1103 		}
1104 	spin_unlock(&queue_lock);
1105 	while (!list_empty(&dequeued)) {
1106 		cr = list_entry(dequeued.next, struct cache_request, q.list);
1107 		list_del(&cr->q.list);
1108 		cache_put(cr->item, detail);
1109 		kfree(cr->buf);
1110 		kfree(cr);
1111 	}
1112 }
1113 
1114 /*
1115  * Support routines for text-based upcalls.
1116  * Fields are separated by spaces.
1117  * Fields are either mangled to quote space tab newline slosh with slosh
1118  * or a hexified with a leading \x
1119  * Record is terminated with newline.
1120  *
1121  */
1122 
qword_add(char ** bpp,int * lp,char * str)1123 void qword_add(char **bpp, int *lp, char *str)
1124 {
1125 	char *bp = *bpp;
1126 	int len = *lp;
1127 	int ret;
1128 
1129 	if (len < 0) return;
1130 
1131 	ret = string_escape_str(str, bp, len, ESCAPE_OCTAL, "\\ \n\t");
1132 	if (ret >= len) {
1133 		bp += len;
1134 		len = -1;
1135 	} else {
1136 		bp += ret;
1137 		len -= ret;
1138 		*bp++ = ' ';
1139 		len--;
1140 	}
1141 	*bpp = bp;
1142 	*lp = len;
1143 }
1144 EXPORT_SYMBOL_GPL(qword_add);
1145 
qword_addhex(char ** bpp,int * lp,char * buf,int blen)1146 void qword_addhex(char **bpp, int *lp, char *buf, int blen)
1147 {
1148 	char *bp = *bpp;
1149 	int len = *lp;
1150 
1151 	if (len < 0) return;
1152 
1153 	if (len > 2) {
1154 		*bp++ = '\\';
1155 		*bp++ = 'x';
1156 		len -= 2;
1157 		while (blen && len >= 2) {
1158 			bp = hex_byte_pack(bp, *buf++);
1159 			len -= 2;
1160 			blen--;
1161 		}
1162 	}
1163 	if (blen || len<1) len = -1;
1164 	else {
1165 		*bp++ = ' ';
1166 		len--;
1167 	}
1168 	*bpp = bp;
1169 	*lp = len;
1170 }
1171 EXPORT_SYMBOL_GPL(qword_addhex);
1172 
warn_no_listener(struct cache_detail * detail)1173 static void warn_no_listener(struct cache_detail *detail)
1174 {
1175 	if (detail->last_warn != detail->last_close) {
1176 		detail->last_warn = detail->last_close;
1177 		if (detail->warn_no_listener)
1178 			detail->warn_no_listener(detail, detail->last_close != 0);
1179 	}
1180 }
1181 
cache_listeners_exist(struct cache_detail * detail)1182 static bool cache_listeners_exist(struct cache_detail *detail)
1183 {
1184 	if (atomic_read(&detail->writers))
1185 		return true;
1186 	if (detail->last_close == 0)
1187 		/* This cache was never opened */
1188 		return false;
1189 	if (detail->last_close < seconds_since_boot() - 30)
1190 		/*
1191 		 * We allow for the possibility that someone might
1192 		 * restart a userspace daemon without restarting the
1193 		 * server; but after 30 seconds, we give up.
1194 		 */
1195 		 return false;
1196 	return true;
1197 }
1198 
1199 /*
1200  * register an upcall request to user-space and queue it up for read() by the
1201  * upcall daemon.
1202  *
1203  * Each request is at most one page long.
1204  */
cache_pipe_upcall(struct cache_detail * detail,struct cache_head * h)1205 static int cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
1206 {
1207 	char *buf;
1208 	struct cache_request *crq;
1209 	int ret = 0;
1210 
1211 	if (test_bit(CACHE_CLEANED, &h->flags))
1212 		/* Too late to make an upcall */
1213 		return -EAGAIN;
1214 
1215 	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1216 	if (!buf)
1217 		return -EAGAIN;
1218 
1219 	crq = kmalloc(sizeof (*crq), GFP_KERNEL);
1220 	if (!crq) {
1221 		kfree(buf);
1222 		return -EAGAIN;
1223 	}
1224 
1225 	crq->q.reader = 0;
1226 	crq->buf = buf;
1227 	crq->len = 0;
1228 	crq->readers = 0;
1229 	spin_lock(&queue_lock);
1230 	if (test_bit(CACHE_PENDING, &h->flags)) {
1231 		crq->item = cache_get(h);
1232 		list_add_tail(&crq->q.list, &detail->queue);
1233 		trace_cache_entry_upcall(detail, h);
1234 	} else
1235 		/* Lost a race, no longer PENDING, so don't enqueue */
1236 		ret = -EAGAIN;
1237 	spin_unlock(&queue_lock);
1238 	wake_up(&queue_wait);
1239 	if (ret == -EAGAIN) {
1240 		kfree(buf);
1241 		kfree(crq);
1242 	}
1243 	return ret;
1244 }
1245 
sunrpc_cache_pipe_upcall(struct cache_detail * detail,struct cache_head * h)1246 int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
1247 {
1248 	if (test_and_set_bit(CACHE_PENDING, &h->flags))
1249 		return 0;
1250 	return cache_pipe_upcall(detail, h);
1251 }
1252 EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall);
1253 
sunrpc_cache_pipe_upcall_timeout(struct cache_detail * detail,struct cache_head * h)1254 int sunrpc_cache_pipe_upcall_timeout(struct cache_detail *detail,
1255 				     struct cache_head *h)
1256 {
1257 	if (!cache_listeners_exist(detail)) {
1258 		warn_no_listener(detail);
1259 		trace_cache_entry_no_listener(detail, h);
1260 		return -EINVAL;
1261 	}
1262 	return sunrpc_cache_pipe_upcall(detail, h);
1263 }
1264 EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall_timeout);
1265 
1266 /*
1267  * parse a message from user-space and pass it
1268  * to an appropriate cache
1269  * Messages are, like requests, separated into fields by
1270  * spaces and dequotes as \xHEXSTRING or embedded \nnn octal
1271  *
1272  * Message is
1273  *   reply cachename expiry key ... content....
1274  *
1275  * key and content are both parsed by cache
1276  */
1277 
qword_get(char ** bpp,char * dest,int bufsize)1278 int qword_get(char **bpp, char *dest, int bufsize)
1279 {
1280 	/* return bytes copied, or -1 on error */
1281 	char *bp = *bpp;
1282 	int len = 0;
1283 
1284 	while (*bp == ' ') bp++;
1285 
1286 	if (bp[0] == '\\' && bp[1] == 'x') {
1287 		/* HEX STRING */
1288 		bp += 2;
1289 		while (len < bufsize - 1) {
1290 			int h, l;
1291 
1292 			h = hex_to_bin(bp[0]);
1293 			if (h < 0)
1294 				break;
1295 
1296 			l = hex_to_bin(bp[1]);
1297 			if (l < 0)
1298 				break;
1299 
1300 			*dest++ = (h << 4) | l;
1301 			bp += 2;
1302 			len++;
1303 		}
1304 	} else {
1305 		/* text with \nnn octal quoting */
1306 		while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) {
1307 			if (*bp == '\\' &&
1308 			    isodigit(bp[1]) && (bp[1] <= '3') &&
1309 			    isodigit(bp[2]) &&
1310 			    isodigit(bp[3])) {
1311 				int byte = (*++bp -'0');
1312 				bp++;
1313 				byte = (byte << 3) | (*bp++ - '0');
1314 				byte = (byte << 3) | (*bp++ - '0');
1315 				*dest++ = byte;
1316 				len++;
1317 			} else {
1318 				*dest++ = *bp++;
1319 				len++;
1320 			}
1321 		}
1322 	}
1323 
1324 	if (*bp != ' ' && *bp != '\n' && *bp != '\0')
1325 		return -1;
1326 	while (*bp == ' ') bp++;
1327 	*bpp = bp;
1328 	*dest = '\0';
1329 	return len;
1330 }
1331 EXPORT_SYMBOL_GPL(qword_get);
1332 
1333 
1334 /*
1335  * support /proc/net/rpc/$CACHENAME/content
1336  * as a seqfile.
1337  * We call ->cache_show passing NULL for the item to
1338  * get a header, then pass each real item in the cache
1339  */
1340 
__cache_seq_start(struct seq_file * m,loff_t * pos)1341 static void *__cache_seq_start(struct seq_file *m, loff_t *pos)
1342 {
1343 	loff_t n = *pos;
1344 	unsigned int hash, entry;
1345 	struct cache_head *ch;
1346 	struct cache_detail *cd = m->private;
1347 
1348 	if (!n--)
1349 		return SEQ_START_TOKEN;
1350 	hash = n >> 32;
1351 	entry = n & ((1LL<<32) - 1);
1352 
1353 	hlist_for_each_entry_rcu(ch, &cd->hash_table[hash], cache_list)
1354 		if (!entry--)
1355 			return ch;
1356 	n &= ~((1LL<<32) - 1);
1357 	do {
1358 		hash++;
1359 		n += 1LL<<32;
1360 	} while(hash < cd->hash_size &&
1361 		hlist_empty(&cd->hash_table[hash]));
1362 	if (hash >= cd->hash_size)
1363 		return NULL;
1364 	*pos = n+1;
1365 	return hlist_entry_safe(rcu_dereference_raw(
1366 				hlist_first_rcu(&cd->hash_table[hash])),
1367 				struct cache_head, cache_list);
1368 }
1369 
cache_seq_next(struct seq_file * m,void * p,loff_t * pos)1370 static void *cache_seq_next(struct seq_file *m, void *p, loff_t *pos)
1371 {
1372 	struct cache_head *ch = p;
1373 	int hash = (*pos >> 32);
1374 	struct cache_detail *cd = m->private;
1375 
1376 	if (p == SEQ_START_TOKEN)
1377 		hash = 0;
1378 	else if (ch->cache_list.next == NULL) {
1379 		hash++;
1380 		*pos += 1LL<<32;
1381 	} else {
1382 		++*pos;
1383 		return hlist_entry_safe(rcu_dereference_raw(
1384 					hlist_next_rcu(&ch->cache_list)),
1385 					struct cache_head, cache_list);
1386 	}
1387 	*pos &= ~((1LL<<32) - 1);
1388 	while (hash < cd->hash_size &&
1389 	       hlist_empty(&cd->hash_table[hash])) {
1390 		hash++;
1391 		*pos += 1LL<<32;
1392 	}
1393 	if (hash >= cd->hash_size)
1394 		return NULL;
1395 	++*pos;
1396 	return hlist_entry_safe(rcu_dereference_raw(
1397 				hlist_first_rcu(&cd->hash_table[hash])),
1398 				struct cache_head, cache_list);
1399 }
1400 
cache_seq_start_rcu(struct seq_file * m,loff_t * pos)1401 void *cache_seq_start_rcu(struct seq_file *m, loff_t *pos)
1402 	__acquires(RCU)
1403 {
1404 	rcu_read_lock();
1405 	return __cache_seq_start(m, pos);
1406 }
1407 EXPORT_SYMBOL_GPL(cache_seq_start_rcu);
1408 
cache_seq_next_rcu(struct seq_file * file,void * p,loff_t * pos)1409 void *cache_seq_next_rcu(struct seq_file *file, void *p, loff_t *pos)
1410 {
1411 	return cache_seq_next(file, p, pos);
1412 }
1413 EXPORT_SYMBOL_GPL(cache_seq_next_rcu);
1414 
cache_seq_stop_rcu(struct seq_file * m,void * p)1415 void cache_seq_stop_rcu(struct seq_file *m, void *p)
1416 	__releases(RCU)
1417 {
1418 	rcu_read_unlock();
1419 }
1420 EXPORT_SYMBOL_GPL(cache_seq_stop_rcu);
1421 
c_show(struct seq_file * m,void * p)1422 static int c_show(struct seq_file *m, void *p)
1423 {
1424 	struct cache_head *cp = p;
1425 	struct cache_detail *cd = m->private;
1426 
1427 	if (p == SEQ_START_TOKEN)
1428 		return cd->cache_show(m, cd, NULL);
1429 
1430 	ifdebug(CACHE)
1431 		seq_printf(m, "# expiry=%lld refcnt=%d flags=%lx\n",
1432 			   convert_to_wallclock(cp->expiry_time),
1433 			   kref_read(&cp->ref), cp->flags);
1434 	cache_get(cp);
1435 	if (cache_check(cd, cp, NULL))
1436 		/* cache_check does a cache_put on failure */
1437 		seq_puts(m, "# ");
1438 	else {
1439 		if (cache_is_expired(cd, cp))
1440 			seq_puts(m, "# ");
1441 		cache_put(cp, cd);
1442 	}
1443 
1444 	return cd->cache_show(m, cd, cp);
1445 }
1446 
1447 static const struct seq_operations cache_content_op = {
1448 	.start	= cache_seq_start_rcu,
1449 	.next	= cache_seq_next_rcu,
1450 	.stop	= cache_seq_stop_rcu,
1451 	.show	= c_show,
1452 };
1453 
content_open(struct inode * inode,struct file * file,struct cache_detail * cd)1454 static int content_open(struct inode *inode, struct file *file,
1455 			struct cache_detail *cd)
1456 {
1457 	struct seq_file *seq;
1458 	int err;
1459 
1460 	if (!cd || !try_module_get(cd->owner))
1461 		return -EACCES;
1462 
1463 	err = seq_open(file, &cache_content_op);
1464 	if (err) {
1465 		module_put(cd->owner);
1466 		return err;
1467 	}
1468 
1469 	seq = file->private_data;
1470 	seq->private = cd;
1471 	return 0;
1472 }
1473 
content_release(struct inode * inode,struct file * file,struct cache_detail * cd)1474 static int content_release(struct inode *inode, struct file *file,
1475 		struct cache_detail *cd)
1476 {
1477 	int ret = seq_release(inode, file);
1478 	module_put(cd->owner);
1479 	return ret;
1480 }
1481 
open_flush(struct inode * inode,struct file * file,struct cache_detail * cd)1482 static int open_flush(struct inode *inode, struct file *file,
1483 			struct cache_detail *cd)
1484 {
1485 	if (!cd || !try_module_get(cd->owner))
1486 		return -EACCES;
1487 	return nonseekable_open(inode, file);
1488 }
1489 
release_flush(struct inode * inode,struct file * file,struct cache_detail * cd)1490 static int release_flush(struct inode *inode, struct file *file,
1491 			struct cache_detail *cd)
1492 {
1493 	module_put(cd->owner);
1494 	return 0;
1495 }
1496 
read_flush(struct file * file,char __user * buf,size_t count,loff_t * ppos,struct cache_detail * cd)1497 static ssize_t read_flush(struct file *file, char __user *buf,
1498 			  size_t count, loff_t *ppos,
1499 			  struct cache_detail *cd)
1500 {
1501 	char tbuf[22];
1502 	size_t len;
1503 
1504 	len = snprintf(tbuf, sizeof(tbuf), "%llu\n",
1505 			convert_to_wallclock(cd->flush_time));
1506 	return simple_read_from_buffer(buf, count, ppos, tbuf, len);
1507 }
1508 
write_flush(struct file * file,const char __user * buf,size_t count,loff_t * ppos,struct cache_detail * cd)1509 static ssize_t write_flush(struct file *file, const char __user *buf,
1510 			   size_t count, loff_t *ppos,
1511 			   struct cache_detail *cd)
1512 {
1513 	char tbuf[20];
1514 	char *ep;
1515 	time64_t now;
1516 
1517 	if (*ppos || count > sizeof(tbuf)-1)
1518 		return -EINVAL;
1519 	if (copy_from_user(tbuf, buf, count))
1520 		return -EFAULT;
1521 	tbuf[count] = 0;
1522 	simple_strtoul(tbuf, &ep, 0);
1523 	if (*ep && *ep != '\n')
1524 		return -EINVAL;
1525 	/* Note that while we check that 'buf' holds a valid number,
1526 	 * we always ignore the value and just flush everything.
1527 	 * Making use of the number leads to races.
1528 	 */
1529 
1530 	now = seconds_since_boot();
1531 	/* Always flush everything, so behave like cache_purge()
1532 	 * Do this by advancing flush_time to the current time,
1533 	 * or by one second if it has already reached the current time.
1534 	 * Newly added cache entries will always have ->last_refresh greater
1535 	 * that ->flush_time, so they don't get flushed prematurely.
1536 	 */
1537 
1538 	if (cd->flush_time >= now)
1539 		now = cd->flush_time + 1;
1540 
1541 	cd->flush_time = now;
1542 	cd->nextcheck = now;
1543 	cache_flush();
1544 
1545 	if (cd->flush)
1546 		cd->flush();
1547 
1548 	*ppos += count;
1549 	return count;
1550 }
1551 
cache_read_procfs(struct file * filp,char __user * buf,size_t count,loff_t * ppos)1552 static ssize_t cache_read_procfs(struct file *filp, char __user *buf,
1553 				 size_t count, loff_t *ppos)
1554 {
1555 	struct cache_detail *cd = pde_data(file_inode(filp));
1556 
1557 	return cache_read(filp, buf, count, ppos, cd);
1558 }
1559 
cache_write_procfs(struct file * filp,const char __user * buf,size_t count,loff_t * ppos)1560 static ssize_t cache_write_procfs(struct file *filp, const char __user *buf,
1561 				  size_t count, loff_t *ppos)
1562 {
1563 	struct cache_detail *cd = pde_data(file_inode(filp));
1564 
1565 	return cache_write(filp, buf, count, ppos, cd);
1566 }
1567 
cache_poll_procfs(struct file * filp,poll_table * wait)1568 static __poll_t cache_poll_procfs(struct file *filp, poll_table *wait)
1569 {
1570 	struct cache_detail *cd = pde_data(file_inode(filp));
1571 
1572 	return cache_poll(filp, wait, cd);
1573 }
1574 
cache_ioctl_procfs(struct file * filp,unsigned int cmd,unsigned long arg)1575 static long cache_ioctl_procfs(struct file *filp,
1576 			       unsigned int cmd, unsigned long arg)
1577 {
1578 	struct inode *inode = file_inode(filp);
1579 	struct cache_detail *cd = pde_data(inode);
1580 
1581 	return cache_ioctl(inode, filp, cmd, arg, cd);
1582 }
1583 
cache_open_procfs(struct inode * inode,struct file * filp)1584 static int cache_open_procfs(struct inode *inode, struct file *filp)
1585 {
1586 	struct cache_detail *cd = pde_data(inode);
1587 
1588 	return cache_open(inode, filp, cd);
1589 }
1590 
cache_release_procfs(struct inode * inode,struct file * filp)1591 static int cache_release_procfs(struct inode *inode, struct file *filp)
1592 {
1593 	struct cache_detail *cd = pde_data(inode);
1594 
1595 	return cache_release(inode, filp, cd);
1596 }
1597 
1598 static const struct proc_ops cache_channel_proc_ops = {
1599 	.proc_lseek	= no_llseek,
1600 	.proc_read	= cache_read_procfs,
1601 	.proc_write	= cache_write_procfs,
1602 	.proc_poll	= cache_poll_procfs,
1603 	.proc_ioctl	= cache_ioctl_procfs, /* for FIONREAD */
1604 	.proc_open	= cache_open_procfs,
1605 	.proc_release	= cache_release_procfs,
1606 };
1607 
content_open_procfs(struct inode * inode,struct file * filp)1608 static int content_open_procfs(struct inode *inode, struct file *filp)
1609 {
1610 	struct cache_detail *cd = pde_data(inode);
1611 
1612 	return content_open(inode, filp, cd);
1613 }
1614 
content_release_procfs(struct inode * inode,struct file * filp)1615 static int content_release_procfs(struct inode *inode, struct file *filp)
1616 {
1617 	struct cache_detail *cd = pde_data(inode);
1618 
1619 	return content_release(inode, filp, cd);
1620 }
1621 
1622 static const struct proc_ops content_proc_ops = {
1623 	.proc_open	= content_open_procfs,
1624 	.proc_read	= seq_read,
1625 	.proc_lseek	= seq_lseek,
1626 	.proc_release	= content_release_procfs,
1627 };
1628 
open_flush_procfs(struct inode * inode,struct file * filp)1629 static int open_flush_procfs(struct inode *inode, struct file *filp)
1630 {
1631 	struct cache_detail *cd = pde_data(inode);
1632 
1633 	return open_flush(inode, filp, cd);
1634 }
1635 
release_flush_procfs(struct inode * inode,struct file * filp)1636 static int release_flush_procfs(struct inode *inode, struct file *filp)
1637 {
1638 	struct cache_detail *cd = pde_data(inode);
1639 
1640 	return release_flush(inode, filp, cd);
1641 }
1642 
read_flush_procfs(struct file * filp,char __user * buf,size_t count,loff_t * ppos)1643 static ssize_t read_flush_procfs(struct file *filp, char __user *buf,
1644 			    size_t count, loff_t *ppos)
1645 {
1646 	struct cache_detail *cd = pde_data(file_inode(filp));
1647 
1648 	return read_flush(filp, buf, count, ppos, cd);
1649 }
1650 
write_flush_procfs(struct file * filp,const char __user * buf,size_t count,loff_t * ppos)1651 static ssize_t write_flush_procfs(struct file *filp,
1652 				  const char __user *buf,
1653 				  size_t count, loff_t *ppos)
1654 {
1655 	struct cache_detail *cd = pde_data(file_inode(filp));
1656 
1657 	return write_flush(filp, buf, count, ppos, cd);
1658 }
1659 
1660 static const struct proc_ops cache_flush_proc_ops = {
1661 	.proc_open	= open_flush_procfs,
1662 	.proc_read	= read_flush_procfs,
1663 	.proc_write	= write_flush_procfs,
1664 	.proc_release	= release_flush_procfs,
1665 	.proc_lseek	= no_llseek,
1666 };
1667 
remove_cache_proc_entries(struct cache_detail * cd)1668 static void remove_cache_proc_entries(struct cache_detail *cd)
1669 {
1670 	if (cd->procfs) {
1671 		proc_remove(cd->procfs);
1672 		cd->procfs = NULL;
1673 	}
1674 }
1675 
1676 #ifdef CONFIG_PROC_FS
create_cache_proc_entries(struct cache_detail * cd,struct net * net)1677 static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1678 {
1679 	struct proc_dir_entry *p;
1680 	struct sunrpc_net *sn;
1681 
1682 	sn = net_generic(net, sunrpc_net_id);
1683 	cd->procfs = proc_mkdir(cd->name, sn->proc_net_rpc);
1684 	if (cd->procfs == NULL)
1685 		goto out_nomem;
1686 
1687 	p = proc_create_data("flush", S_IFREG | 0600,
1688 			     cd->procfs, &cache_flush_proc_ops, cd);
1689 	if (p == NULL)
1690 		goto out_nomem;
1691 
1692 	if (cd->cache_request || cd->cache_parse) {
1693 		p = proc_create_data("channel", S_IFREG | 0600, cd->procfs,
1694 				     &cache_channel_proc_ops, cd);
1695 		if (p == NULL)
1696 			goto out_nomem;
1697 	}
1698 	if (cd->cache_show) {
1699 		p = proc_create_data("content", S_IFREG | 0400, cd->procfs,
1700 				     &content_proc_ops, cd);
1701 		if (p == NULL)
1702 			goto out_nomem;
1703 	}
1704 	return 0;
1705 out_nomem:
1706 	remove_cache_proc_entries(cd);
1707 	return -ENOMEM;
1708 }
1709 #else /* CONFIG_PROC_FS */
create_cache_proc_entries(struct cache_detail * cd,struct net * net)1710 static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1711 {
1712 	return 0;
1713 }
1714 #endif
1715 
cache_initialize(void)1716 void __init cache_initialize(void)
1717 {
1718 	INIT_DEFERRABLE_WORK(&cache_cleaner, do_cache_clean);
1719 }
1720 
cache_register_net(struct cache_detail * cd,struct net * net)1721 int cache_register_net(struct cache_detail *cd, struct net *net)
1722 {
1723 	int ret;
1724 
1725 	sunrpc_init_cache_detail(cd);
1726 	ret = create_cache_proc_entries(cd, net);
1727 	if (ret)
1728 		sunrpc_destroy_cache_detail(cd);
1729 	return ret;
1730 }
1731 EXPORT_SYMBOL_GPL(cache_register_net);
1732 
cache_unregister_net(struct cache_detail * cd,struct net * net)1733 void cache_unregister_net(struct cache_detail *cd, struct net *net)
1734 {
1735 	remove_cache_proc_entries(cd);
1736 	sunrpc_destroy_cache_detail(cd);
1737 }
1738 EXPORT_SYMBOL_GPL(cache_unregister_net);
1739 
cache_create_net(const struct cache_detail * tmpl,struct net * net)1740 struct cache_detail *cache_create_net(const struct cache_detail *tmpl, struct net *net)
1741 {
1742 	struct cache_detail *cd;
1743 	int i;
1744 
1745 	cd = kmemdup(tmpl, sizeof(struct cache_detail), GFP_KERNEL);
1746 	if (cd == NULL)
1747 		return ERR_PTR(-ENOMEM);
1748 
1749 	cd->hash_table = kcalloc(cd->hash_size, sizeof(struct hlist_head),
1750 				 GFP_KERNEL);
1751 	if (cd->hash_table == NULL) {
1752 		kfree(cd);
1753 		return ERR_PTR(-ENOMEM);
1754 	}
1755 
1756 	for (i = 0; i < cd->hash_size; i++)
1757 		INIT_HLIST_HEAD(&cd->hash_table[i]);
1758 	cd->net = net;
1759 	return cd;
1760 }
1761 EXPORT_SYMBOL_GPL(cache_create_net);
1762 
cache_destroy_net(struct cache_detail * cd,struct net * net)1763 void cache_destroy_net(struct cache_detail *cd, struct net *net)
1764 {
1765 	kfree(cd->hash_table);
1766 	kfree(cd);
1767 }
1768 EXPORT_SYMBOL_GPL(cache_destroy_net);
1769 
cache_read_pipefs(struct file * filp,char __user * buf,size_t count,loff_t * ppos)1770 static ssize_t cache_read_pipefs(struct file *filp, char __user *buf,
1771 				 size_t count, loff_t *ppos)
1772 {
1773 	struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1774 
1775 	return cache_read(filp, buf, count, ppos, cd);
1776 }
1777 
cache_write_pipefs(struct file * filp,const char __user * buf,size_t count,loff_t * ppos)1778 static ssize_t cache_write_pipefs(struct file *filp, const char __user *buf,
1779 				  size_t count, loff_t *ppos)
1780 {
1781 	struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1782 
1783 	return cache_write(filp, buf, count, ppos, cd);
1784 }
1785 
cache_poll_pipefs(struct file * filp,poll_table * wait)1786 static __poll_t cache_poll_pipefs(struct file *filp, poll_table *wait)
1787 {
1788 	struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1789 
1790 	return cache_poll(filp, wait, cd);
1791 }
1792 
cache_ioctl_pipefs(struct file * filp,unsigned int cmd,unsigned long arg)1793 static long cache_ioctl_pipefs(struct file *filp,
1794 			      unsigned int cmd, unsigned long arg)
1795 {
1796 	struct inode *inode = file_inode(filp);
1797 	struct cache_detail *cd = RPC_I(inode)->private;
1798 
1799 	return cache_ioctl(inode, filp, cmd, arg, cd);
1800 }
1801 
cache_open_pipefs(struct inode * inode,struct file * filp)1802 static int cache_open_pipefs(struct inode *inode, struct file *filp)
1803 {
1804 	struct cache_detail *cd = RPC_I(inode)->private;
1805 
1806 	return cache_open(inode, filp, cd);
1807 }
1808 
cache_release_pipefs(struct inode * inode,struct file * filp)1809 static int cache_release_pipefs(struct inode *inode, struct file *filp)
1810 {
1811 	struct cache_detail *cd = RPC_I(inode)->private;
1812 
1813 	return cache_release(inode, filp, cd);
1814 }
1815 
1816 const struct file_operations cache_file_operations_pipefs = {
1817 	.owner		= THIS_MODULE,
1818 	.llseek		= no_llseek,
1819 	.read		= cache_read_pipefs,
1820 	.write		= cache_write_pipefs,
1821 	.poll		= cache_poll_pipefs,
1822 	.unlocked_ioctl	= cache_ioctl_pipefs, /* for FIONREAD */
1823 	.open		= cache_open_pipefs,
1824 	.release	= cache_release_pipefs,
1825 };
1826 
content_open_pipefs(struct inode * inode,struct file * filp)1827 static int content_open_pipefs(struct inode *inode, struct file *filp)
1828 {
1829 	struct cache_detail *cd = RPC_I(inode)->private;
1830 
1831 	return content_open(inode, filp, cd);
1832 }
1833 
content_release_pipefs(struct inode * inode,struct file * filp)1834 static int content_release_pipefs(struct inode *inode, struct file *filp)
1835 {
1836 	struct cache_detail *cd = RPC_I(inode)->private;
1837 
1838 	return content_release(inode, filp, cd);
1839 }
1840 
1841 const struct file_operations content_file_operations_pipefs = {
1842 	.open		= content_open_pipefs,
1843 	.read		= seq_read,
1844 	.llseek		= seq_lseek,
1845 	.release	= content_release_pipefs,
1846 };
1847 
open_flush_pipefs(struct inode * inode,struct file * filp)1848 static int open_flush_pipefs(struct inode *inode, struct file *filp)
1849 {
1850 	struct cache_detail *cd = RPC_I(inode)->private;
1851 
1852 	return open_flush(inode, filp, cd);
1853 }
1854 
release_flush_pipefs(struct inode * inode,struct file * filp)1855 static int release_flush_pipefs(struct inode *inode, struct file *filp)
1856 {
1857 	struct cache_detail *cd = RPC_I(inode)->private;
1858 
1859 	return release_flush(inode, filp, cd);
1860 }
1861 
read_flush_pipefs(struct file * filp,char __user * buf,size_t count,loff_t * ppos)1862 static ssize_t read_flush_pipefs(struct file *filp, char __user *buf,
1863 			    size_t count, loff_t *ppos)
1864 {
1865 	struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1866 
1867 	return read_flush(filp, buf, count, ppos, cd);
1868 }
1869 
write_flush_pipefs(struct file * filp,const char __user * buf,size_t count,loff_t * ppos)1870 static ssize_t write_flush_pipefs(struct file *filp,
1871 				  const char __user *buf,
1872 				  size_t count, loff_t *ppos)
1873 {
1874 	struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1875 
1876 	return write_flush(filp, buf, count, ppos, cd);
1877 }
1878 
1879 const struct file_operations cache_flush_operations_pipefs = {
1880 	.open		= open_flush_pipefs,
1881 	.read		= read_flush_pipefs,
1882 	.write		= write_flush_pipefs,
1883 	.release	= release_flush_pipefs,
1884 	.llseek		= no_llseek,
1885 };
1886 
sunrpc_cache_register_pipefs(struct dentry * parent,const char * name,umode_t umode,struct cache_detail * cd)1887 int sunrpc_cache_register_pipefs(struct dentry *parent,
1888 				 const char *name, umode_t umode,
1889 				 struct cache_detail *cd)
1890 {
1891 	struct dentry *dir = rpc_create_cache_dir(parent, name, umode, cd);
1892 	if (IS_ERR(dir))
1893 		return PTR_ERR(dir);
1894 	cd->pipefs = dir;
1895 	return 0;
1896 }
1897 EXPORT_SYMBOL_GPL(sunrpc_cache_register_pipefs);
1898 
sunrpc_cache_unregister_pipefs(struct cache_detail * cd)1899 void sunrpc_cache_unregister_pipefs(struct cache_detail *cd)
1900 {
1901 	if (cd->pipefs) {
1902 		rpc_remove_cache_dir(cd->pipefs);
1903 		cd->pipefs = NULL;
1904 	}
1905 }
1906 EXPORT_SYMBOL_GPL(sunrpc_cache_unregister_pipefs);
1907 
sunrpc_cache_unhash(struct cache_detail * cd,struct cache_head * h)1908 void sunrpc_cache_unhash(struct cache_detail *cd, struct cache_head *h)
1909 {
1910 	spin_lock(&cd->hash_lock);
1911 	if (!hlist_unhashed(&h->cache_list)){
1912 		sunrpc_begin_cache_remove_entry(h, cd);
1913 		spin_unlock(&cd->hash_lock);
1914 		sunrpc_end_cache_remove_entry(h, cd);
1915 	} else
1916 		spin_unlock(&cd->hash_lock);
1917 }
1918 EXPORT_SYMBOL_GPL(sunrpc_cache_unhash);
1919