Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * include/linux/sunrpc/cache.h | |
3 | * | |
4 | * Generic code for various authentication-related caches | |
5 | * used by sunrpc clients and servers. | |
6 | * | |
7 | * Copyright (C) 2002 Neil Brown <neilb@cse.unsw.edu.au> | |
8 | * | |
9 | * Released under terms in GPL version 2. See COPYING. | |
10 | * | |
11 | */ | |
12 | ||
13 | #ifndef _LINUX_SUNRPC_CACHE_H_ | |
14 | #define _LINUX_SUNRPC_CACHE_H_ | |
15 | ||
16 | #include <linux/slab.h> | |
17 | #include <asm/atomic.h> | |
18 | #include <linux/proc_fs.h> | |
19 | ||
20 | /* | |
21 | * Each cache requires: | |
22 | * - A 'struct cache_detail' which contains information specific to the cache | |
23 | * for common code to use. | |
24 | * - An item structure that must contain a "struct cache_head" | |
25 | * - A lookup function defined using DefineCacheLookup | |
26 | * - A 'put' function that can release a cache item. It will only | |
27 | * be called after cache_put has succeed, so there are guarantee | |
28 | * to be no references. | |
29 | * - A function to calculate a hash of an item's key. | |
30 | * | |
31 | * as well as assorted code fragments (e.g. compare keys) and numbers | |
32 | * (e.g. hash size, goal_age, etc). | |
33 | * | |
34 | * Each cache must be registered so that it can be cleaned regularly. | |
35 | * When the cache is unregistered, it is flushed completely. | |
36 | * | |
37 | * Entries have a ref count and a 'hashed' flag which counts the existance | |
38 | * in the hash table. | |
39 | * We only expire entries when refcount is zero. | |
40 | * Existance in the cache is counted the refcount. | |
41 | */ | |
42 | ||
43 | /* Every cache item has a common header that is used | |
44 | * for expiring and refreshing entries. | |
45 | * | |
46 | */ | |
47 | struct cache_head { | |
48 | struct cache_head * next; | |
49 | time_t expiry_time; /* After time time, don't use the data */ | |
50 | time_t last_refresh; /* If CACHE_PENDING, this is when upcall | |
51 | * was sent, else this is when update was received | |
52 | */ | |
baab935f | 53 | struct kref ref; |
1da177e4 LT |
54 | unsigned long flags; |
55 | }; | |
56 | #define CACHE_VALID 0 /* Entry contains valid data */ | |
57 | #define CACHE_NEGATIVE 1 /* Negative entry - there is no match for the key */ | |
58 | #define CACHE_PENDING 2 /* An upcall has been sent but no reply received yet*/ | |
59 | ||
60 | #define CACHE_NEW_EXPIRY 120 /* keep new things pending confirmation for 120 seconds */ | |
61 | ||
173912a6 TM |
62 | struct cache_detail_procfs { |
63 | struct proc_dir_entry *proc_ent; | |
64 | struct proc_dir_entry *flush_ent, *channel_ent, *content_ent; | |
65 | }; | |
66 | ||
8854e82d TM |
67 | struct cache_detail_pipefs { |
68 | struct dentry *dir; | |
69 | }; | |
70 | ||
1da177e4 | 71 | struct cache_detail { |
f35279d3 | 72 | struct module * owner; |
1da177e4 LT |
73 | int hash_size; |
74 | struct cache_head ** hash_table; | |
75 | rwlock_t hash_lock; | |
76 | ||
77 | atomic_t inuse; /* active user-space update or lookup */ | |
78 | ||
79 | char *name; | |
baab935f | 80 | void (*cache_put)(struct kref *); |
1da177e4 | 81 | |
bc74b4f5 TM |
82 | int (*cache_upcall)(struct cache_detail *, |
83 | struct cache_head *); | |
84 | ||
1da177e4 LT |
85 | int (*cache_parse)(struct cache_detail *, |
86 | char *buf, int len); | |
87 | ||
88 | int (*cache_show)(struct seq_file *m, | |
89 | struct cache_detail *cd, | |
90 | struct cache_head *h); | |
2da8ca26 TM |
91 | void (*warn_no_listener)(struct cache_detail *cd, |
92 | int has_died); | |
1da177e4 | 93 | |
15a5f6bd N |
94 | struct cache_head * (*alloc)(void); |
95 | int (*match)(struct cache_head *orig, struct cache_head *new); | |
96 | void (*init)(struct cache_head *orig, struct cache_head *new); | |
97 | void (*update)(struct cache_head *orig, struct cache_head *new); | |
98 | ||
1da177e4 LT |
99 | /* fields below this comment are for internal use |
100 | * and should not be touched by cache owners | |
101 | */ | |
102 | time_t flush_time; /* flush all cache items with last_refresh | |
103 | * earlier than this */ | |
104 | struct list_head others; | |
105 | time_t nextcheck; | |
106 | int entries; | |
107 | ||
108 | /* fields for communication over channel */ | |
109 | struct list_head queue; | |
1da177e4 LT |
110 | |
111 | atomic_t readers; /* how many time is /chennel open */ | |
112 | time_t last_close; /* if no readers, when did last close */ | |
113 | time_t last_warn; /* when we last warned about no readers */ | |
173912a6 TM |
114 | |
115 | union { | |
116 | struct cache_detail_procfs procfs; | |
8854e82d | 117 | struct cache_detail_pipefs pipefs; |
173912a6 | 118 | } u; |
1da177e4 LT |
119 | }; |
120 | ||
121 | ||
122 | /* this must be embedded in any request structure that | |
123 | * identifies an object that will want a callback on | |
124 | * a cache fill | |
125 | */ | |
126 | struct cache_req { | |
127 | struct cache_deferred_req *(*defer)(struct cache_req *req); | |
128 | }; | |
129 | /* this must be embedded in a deferred_request that is being | |
130 | * delayed awaiting cache-fill | |
131 | */ | |
132 | struct cache_deferred_req { | |
133 | struct list_head hash; /* on hash chain */ | |
134 | struct list_head recent; /* on fifo */ | |
135 | struct cache_head *item; /* cache item we wait on */ | |
1da177e4 LT |
136 | void *owner; /* we might need to discard all defered requests |
137 | * owned by someone */ | |
138 | void (*revisit)(struct cache_deferred_req *req, | |
139 | int too_many); | |
140 | }; | |
141 | ||
7d317f2c | 142 | |
8854e82d TM |
143 | extern const struct file_operations cache_file_operations_pipefs; |
144 | extern const struct file_operations content_file_operations_pipefs; | |
145 | extern const struct file_operations cache_flush_operations_pipefs; | |
146 | ||
15a5f6bd N |
147 | extern struct cache_head * |
148 | sunrpc_cache_lookup(struct cache_detail *detail, | |
149 | struct cache_head *key, int hash); | |
150 | extern struct cache_head * | |
151 | sunrpc_cache_update(struct cache_detail *detail, | |
152 | struct cache_head *new, struct cache_head *old, int hash); | |
153 | ||
bc74b4f5 TM |
154 | extern int |
155 | sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h, | |
156 | void (*cache_request)(struct cache_detail *, | |
157 | struct cache_head *, | |
158 | char **, | |
159 | int *)); | |
160 | ||
1da177e4 | 161 | |
1da177e4 LT |
162 | extern void cache_clean_deferred(void *owner); |
163 | ||
164 | static inline struct cache_head *cache_get(struct cache_head *h) | |
165 | { | |
baab935f | 166 | kref_get(&h->ref); |
1da177e4 LT |
167 | return h; |
168 | } | |
169 | ||
170 | ||
baab935f | 171 | static inline void cache_put(struct cache_head *h, struct cache_detail *cd) |
1da177e4 | 172 | { |
baab935f | 173 | if (atomic_read(&h->ref.refcount) <= 2 && |
1da177e4 LT |
174 | h->expiry_time < cd->nextcheck) |
175 | cd->nextcheck = h->expiry_time; | |
baab935f | 176 | kref_put(&h->ref, cd->cache_put); |
1da177e4 LT |
177 | } |
178 | ||
7b2b1fee GB |
179 | static inline int cache_valid(struct cache_head *h) |
180 | { | |
181 | /* If an item has been unhashed pending removal when | |
182 | * the refcount drops to 0, the expiry_time will be | |
183 | * set to 0. We don't want to consider such items | |
184 | * valid in this context even though CACHE_VALID is | |
185 | * set. | |
186 | */ | |
187 | return (h->expiry_time != 0 && test_bit(CACHE_VALID, &h->flags)); | |
188 | } | |
189 | ||
1da177e4 LT |
190 | extern int cache_check(struct cache_detail *detail, |
191 | struct cache_head *h, struct cache_req *rqstp); | |
192 | extern void cache_flush(void); | |
193 | extern void cache_purge(struct cache_detail *detail); | |
194 | #define NEVER (0x7FFFFFFF) | |
8eab945c | 195 | extern void __init cache_initialize(void); |
dbf847ec | 196 | extern int cache_register(struct cache_detail *cd); |
df95a9d4 | 197 | extern void cache_unregister(struct cache_detail *cd); |
1da177e4 | 198 | |
8854e82d TM |
199 | extern int sunrpc_cache_register_pipefs(struct dentry *parent, const char *, |
200 | mode_t, struct cache_detail *); | |
201 | extern void sunrpc_cache_unregister_pipefs(struct cache_detail *); | |
202 | ||
1da177e4 LT |
203 | extern void qword_add(char **bpp, int *lp, char *str); |
204 | extern void qword_addhex(char **bpp, int *lp, char *buf, int blen); | |
205 | extern int qword_get(char **bpp, char *dest, int bufsize); | |
206 | ||
207 | static inline int get_int(char **bpp, int *anint) | |
208 | { | |
209 | char buf[50]; | |
210 | char *ep; | |
211 | int rv; | |
212 | int len = qword_get(bpp, buf, 50); | |
213 | if (len < 0) return -EINVAL; | |
214 | if (len ==0) return -ENOENT; | |
215 | rv = simple_strtol(buf, &ep, 0); | |
216 | if (*ep) return -EINVAL; | |
217 | *anint = rv; | |
218 | return 0; | |
219 | } | |
220 | ||
c5b29f88 N |
221 | /* |
222 | * timestamps kept in the cache are expressed in seconds | |
223 | * since boot. This is the best for measuring differences in | |
224 | * real time. | |
225 | */ | |
226 | static inline time_t seconds_since_boot(void) | |
227 | { | |
228 | struct timespec boot; | |
229 | getboottime(&boot); | |
230 | return get_seconds() - boot.tv_sec; | |
231 | } | |
232 | ||
233 | static inline time_t convert_to_wallclock(time_t sinceboot) | |
234 | { | |
235 | struct timespec boot; | |
236 | getboottime(&boot); | |
237 | return boot.tv_sec + sinceboot; | |
238 | } | |
239 | ||
1da177e4 LT |
240 | static inline time_t get_expiry(char **bpp) |
241 | { | |
242 | int rv; | |
c5b29f88 N |
243 | struct timespec boot; |
244 | ||
1da177e4 LT |
245 | if (get_int(bpp, &rv)) |
246 | return 0; | |
247 | if (rv < 0) | |
248 | return 0; | |
c5b29f88 N |
249 | getboottime(&boot); |
250 | return rv - boot.tv_sec; | |
1da177e4 LT |
251 | } |
252 | ||
17cebf65 N |
253 | static inline void sunrpc_invalidate(struct cache_head *h, |
254 | struct cache_detail *detail) | |
255 | { | |
c5b29f88 N |
256 | h->expiry_time = seconds_since_boot() - 1; |
257 | detail->nextcheck = seconds_since_boot(); | |
17cebf65 | 258 | } |
1da177e4 | 259 | #endif /* _LINUX_SUNRPC_CACHE_H_ */ |