2 * include/linux/sunrpc/cache.h
4 * Generic code for various authentication-related caches
5 * used by sunrpc clients and servers.
7 * Copyright (C) 2002 Neil Brown <neilb@cse.unsw.edu.au>
9 * Released under terms in GPL version 2. See COPYING.
13 #ifndef _LINUX_SUNRPC_CACHE_H_
14 #define _LINUX_SUNRPC_CACHE_H_
16 #include <linux/kref.h>
17 #include <linux/slab.h>
18 #include <linux/atomic.h>
19 #include <linux/proc_fs.h>
22 * Each cache requires:
23 * - A 'struct cache_detail' which contains information specific to the cache
24 * for common code to use.
25 * - An item structure that must contain a "struct cache_head"
26 * - A lookup function defined using DefineCacheLookup
27 * - A 'put' function that can release a cache item. It will only
28 * be called after cache_put has succeed, so there are guarantee
29 * to be no references.
30 * - A function to calculate a hash of an item's key.
32 * as well as assorted code fragments (e.g. compare keys) and numbers
33 * (e.g. hash size, goal_age, etc).
35 * Each cache must be registered so that it can be cleaned regularly.
36 * When the cache is unregistered, it is flushed completely.
38 * Entries have a ref count and a 'hashed' flag which counts the existence
40 * We only expire entries when refcount is zero.
41 * Existence in the cache is counted the refcount.
44 /* Every cache item has a common header that is used
45 * for expiring and refreshing entries.
49 struct hlist_node cache_list
;
50 time_t expiry_time
; /* After time time, don't use the data */
51 time_t last_refresh
; /* If CACHE_PENDING, this is when upcall was
52 * sent, else this is when update was
53 * received, though it is alway set to
54 * be *after* ->flush_time.
59 #define CACHE_VALID 0 /* Entry contains valid data */
60 #define CACHE_NEGATIVE 1 /* Negative entry - there is no match for the key */
61 #define CACHE_PENDING 2 /* An upcall has been sent but no reply received yet*/
62 #define CACHE_CLEANED 3 /* Entry has been cleaned from cache */
64 #define CACHE_NEW_EXPIRY 120 /* keep new things pending confirmation for 120 seconds */
66 struct cache_detail_procfs
{
67 struct proc_dir_entry
*proc_ent
;
68 struct proc_dir_entry
*flush_ent
, *channel_ent
, *content_ent
;
71 struct cache_detail_pipefs
{
76 struct module
* owner
;
78 struct hlist_head
* hash_table
;
81 atomic_t inuse
; /* active user-space update or lookup */
84 void (*cache_put
)(struct kref
*);
86 int (*cache_upcall
)(struct cache_detail
*,
89 void (*cache_request
)(struct cache_detail
*cd
,
90 struct cache_head
*ch
,
91 char **bpp
, int *blen
);
93 int (*cache_parse
)(struct cache_detail
*,
96 int (*cache_show
)(struct seq_file
*m
,
97 struct cache_detail
*cd
,
98 struct cache_head
*h
);
99 void (*warn_no_listener
)(struct cache_detail
*cd
,
102 struct cache_head
* (*alloc
)(void);
103 int (*match
)(struct cache_head
*orig
, struct cache_head
*new);
104 void (*init
)(struct cache_head
*orig
, struct cache_head
*new);
105 void (*update
)(struct cache_head
*orig
, struct cache_head
*new);
107 /* fields below this comment are for internal use
108 * and should not be touched by cache owners
110 time_t flush_time
; /* flush all cache items with
111 * last_refresh at or earlier
112 * than this. last_refresh
113 * is never set at or earlier
116 struct list_head others
;
120 /* fields for communication over channel */
121 struct list_head queue
;
123 atomic_t readers
; /* how many time is /chennel open */
124 time_t last_close
; /* if no readers, when did last close */
125 time_t last_warn
; /* when we last warned about no readers */
128 struct cache_detail_procfs procfs
;
129 struct cache_detail_pipefs pipefs
;
135 /* this must be embedded in any request structure that
136 * identifies an object that will want a callback on
140 struct cache_deferred_req
*(*defer
)(struct cache_req
*req
);
141 int thread_wait
; /* How long (jiffies) we can block the
142 * current thread to wait for updates.
145 /* this must be embedded in a deferred_request that is being
146 * delayed awaiting cache-fill
148 struct cache_deferred_req
{
149 struct hlist_node hash
; /* on hash chain */
150 struct list_head recent
; /* on fifo */
151 struct cache_head
*item
; /* cache item we wait on */
152 void *owner
; /* we might need to discard all defered requests
153 * owned by someone */
154 void (*revisit
)(struct cache_deferred_req
*req
,
159 * timestamps kept in the cache are expressed in seconds
160 * since boot. This is the best for measuring differences in
163 static inline time_t seconds_since_boot(void)
165 struct timespec boot
;
167 return get_seconds() - boot
.tv_sec
;
170 static inline time_t convert_to_wallclock(time_t sinceboot
)
172 struct timespec boot
;
174 return boot
.tv_sec
+ sinceboot
;
177 extern const struct file_operations cache_file_operations_pipefs
;
178 extern const struct file_operations content_file_operations_pipefs
;
179 extern const struct file_operations cache_flush_operations_pipefs
;
181 extern struct cache_head
*
182 sunrpc_cache_lookup(struct cache_detail
*detail
,
183 struct cache_head
*key
, int hash
);
184 extern struct cache_head
*
185 sunrpc_cache_update(struct cache_detail
*detail
,
186 struct cache_head
*new, struct cache_head
*old
, int hash
);
189 sunrpc_cache_pipe_upcall(struct cache_detail
*detail
, struct cache_head
*h
);
192 extern void cache_clean_deferred(void *owner
);
194 static inline struct cache_head
*cache_get(struct cache_head
*h
)
201 static inline void cache_put(struct cache_head
*h
, struct cache_detail
*cd
)
203 if (atomic_read(&h
->ref
.refcount
) <= 2 &&
204 h
->expiry_time
< cd
->nextcheck
)
205 cd
->nextcheck
= h
->expiry_time
;
206 kref_put(&h
->ref
, cd
->cache_put
);
209 static inline int cache_is_expired(struct cache_detail
*detail
, struct cache_head
*h
)
211 return (h
->expiry_time
< seconds_since_boot()) ||
212 (detail
->flush_time
>= h
->last_refresh
);
215 extern int cache_check(struct cache_detail
*detail
,
216 struct cache_head
*h
, struct cache_req
*rqstp
);
217 extern void cache_flush(void);
218 extern void cache_purge(struct cache_detail
*detail
);
219 #define NEVER (0x7FFFFFFF)
220 extern void __init
cache_initialize(void);
221 extern int cache_register_net(struct cache_detail
*cd
, struct net
*net
);
222 extern void cache_unregister_net(struct cache_detail
*cd
, struct net
*net
);
224 extern struct cache_detail
*cache_create_net(struct cache_detail
*tmpl
, struct net
*net
);
225 extern void cache_destroy_net(struct cache_detail
*cd
, struct net
*net
);
227 extern void sunrpc_init_cache_detail(struct cache_detail
*cd
);
228 extern void sunrpc_destroy_cache_detail(struct cache_detail
*cd
);
229 extern int sunrpc_cache_register_pipefs(struct dentry
*parent
, const char *,
230 umode_t
, struct cache_detail
*);
231 extern void sunrpc_cache_unregister_pipefs(struct cache_detail
*);
233 /* Must store cache_detail in seq_file->private if using next three functions */
234 extern void *cache_seq_start(struct seq_file
*file
, loff_t
*pos
);
235 extern void *cache_seq_next(struct seq_file
*file
, void *p
, loff_t
*pos
);
236 extern void cache_seq_stop(struct seq_file
*file
, void *p
);
238 extern void qword_add(char **bpp
, int *lp
, char *str
);
239 extern void qword_addhex(char **bpp
, int *lp
, char *buf
, int blen
);
240 extern int qword_get(char **bpp
, char *dest
, int bufsize
);
242 static inline int get_int(char **bpp
, int *anint
)
247 int len
= qword_get(bpp
, buf
, sizeof(buf
));
254 rv
= simple_strtol(buf
, &ep
, 0);
262 static inline int get_uint(char **bpp
, unsigned int *anint
)
265 int len
= qword_get(bpp
, buf
, sizeof(buf
));
272 if (kstrtouint(buf
, 0, anint
))
278 static inline int get_time(char **bpp
, time_t *time
)
282 int len
= qword_get(bpp
, buf
, sizeof(buf
));
289 if (kstrtoll(buf
, 0, &ll
))
296 static inline time_t get_expiry(char **bpp
)
299 struct timespec boot
;
301 if (get_time(bpp
, &rv
))
306 return rv
- boot
.tv_sec
;
309 #endif /* _LINUX_SUNRPC_CACHE_H_ */