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 | ||
57cc7215 | 16 | #include <linux/kref.h> |
1da177e4 | 17 | #include <linux/slab.h> |
60063497 | 18 | #include <linux/atomic.h> |
1da177e4 LT |
19 | #include <linux/proc_fs.h> |
20 | ||
21 | /* | |
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. | |
31 | * | |
32 | * as well as assorted code fragments (e.g. compare keys) and numbers | |
33 | * (e.g. hash size, goal_age, etc). | |
34 | * | |
35 | * Each cache must be registered so that it can be cleaned regularly. | |
36 | * When the cache is unregistered, it is flushed completely. | |
37 | * | |
25985edc | 38 | * Entries have a ref count and a 'hashed' flag which counts the existence |
1da177e4 LT |
39 | * in the hash table. |
40 | * We only expire entries when refcount is zero. | |
25985edc | 41 | * Existence in the cache is counted the refcount. |
1da177e4 LT |
42 | */ |
43 | ||
44 | /* Every cache item has a common header that is used | |
45 | * for expiring and refreshing entries. | |
46 | * | |
47 | */ | |
48 | struct cache_head { | |
49 | struct cache_head * next; | |
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 | |
52 | * was sent, else this is when update was received | |
53 | */ | |
baab935f | 54 | struct kref ref; |
1da177e4 LT |
55 | unsigned long flags; |
56 | }; | |
57 | #define CACHE_VALID 0 /* Entry contains valid data */ | |
58 | #define CACHE_NEGATIVE 1 /* Negative entry - there is no match for the key */ | |
59 | #define CACHE_PENDING 2 /* An upcall has been sent but no reply received yet*/ | |
013920eb | 60 | #define CACHE_CLEANED 3 /* Entry has been cleaned from cache */ |
1da177e4 LT |
61 | |
62 | #define CACHE_NEW_EXPIRY 120 /* keep new things pending confirmation for 120 seconds */ | |
63 | ||
173912a6 TM |
64 | struct cache_detail_procfs { |
65 | struct proc_dir_entry *proc_ent; | |
66 | struct proc_dir_entry *flush_ent, *channel_ent, *content_ent; | |
67 | }; | |
68 | ||
8854e82d TM |
69 | struct cache_detail_pipefs { |
70 | struct dentry *dir; | |
71 | }; | |
72 | ||
1da177e4 | 73 | struct cache_detail { |
f35279d3 | 74 | struct module * owner; |
1da177e4 LT |
75 | int hash_size; |
76 | struct cache_head ** hash_table; | |
77 | rwlock_t hash_lock; | |
78 | ||
79 | atomic_t inuse; /* active user-space update or lookup */ | |
80 | ||
81 | char *name; | |
baab935f | 82 | void (*cache_put)(struct kref *); |
1da177e4 | 83 | |
bc74b4f5 TM |
84 | int (*cache_upcall)(struct cache_detail *, |
85 | struct cache_head *); | |
86 | ||
73fb847a SK |
87 | void (*cache_request)(struct cache_detail *cd, |
88 | struct cache_head *ch, | |
89 | char **bpp, int *blen); | |
90 | ||
1da177e4 LT |
91 | int (*cache_parse)(struct cache_detail *, |
92 | char *buf, int len); | |
93 | ||
94 | int (*cache_show)(struct seq_file *m, | |
95 | struct cache_detail *cd, | |
96 | struct cache_head *h); | |
2da8ca26 TM |
97 | void (*warn_no_listener)(struct cache_detail *cd, |
98 | int has_died); | |
1da177e4 | 99 | |
15a5f6bd N |
100 | struct cache_head * (*alloc)(void); |
101 | int (*match)(struct cache_head *orig, struct cache_head *new); | |
102 | void (*init)(struct cache_head *orig, struct cache_head *new); | |
103 | void (*update)(struct cache_head *orig, struct cache_head *new); | |
104 | ||
1da177e4 LT |
105 | /* fields below this comment are for internal use |
106 | * and should not be touched by cache owners | |
107 | */ | |
108 | time_t flush_time; /* flush all cache items with last_refresh | |
109 | * earlier than this */ | |
110 | struct list_head others; | |
111 | time_t nextcheck; | |
112 | int entries; | |
113 | ||
114 | /* fields for communication over channel */ | |
115 | struct list_head queue; | |
1da177e4 LT |
116 | |
117 | atomic_t readers; /* how many time is /chennel open */ | |
118 | time_t last_close; /* if no readers, when did last close */ | |
119 | time_t last_warn; /* when we last warned about no readers */ | |
173912a6 TM |
120 | |
121 | union { | |
122 | struct cache_detail_procfs procfs; | |
8854e82d | 123 | struct cache_detail_pipefs pipefs; |
173912a6 | 124 | } u; |
0a402d5a | 125 | struct net *net; |
1da177e4 LT |
126 | }; |
127 | ||
128 | ||
129 | /* this must be embedded in any request structure that | |
130 | * identifies an object that will want a callback on | |
131 | * a cache fill | |
132 | */ | |
133 | struct cache_req { | |
134 | struct cache_deferred_req *(*defer)(struct cache_req *req); | |
f16b6e8d N |
135 | int thread_wait; /* How long (jiffies) we can block the |
136 | * current thread to wait for updates. | |
137 | */ | |
1da177e4 LT |
138 | }; |
139 | /* this must be embedded in a deferred_request that is being | |
140 | * delayed awaiting cache-fill | |
141 | */ | |
142 | struct cache_deferred_req { | |
11174492 | 143 | struct hlist_node hash; /* on hash chain */ |
1da177e4 LT |
144 | struct list_head recent; /* on fifo */ |
145 | struct cache_head *item; /* cache item we wait on */ | |
1da177e4 LT |
146 | void *owner; /* we might need to discard all defered requests |
147 | * owned by someone */ | |
148 | void (*revisit)(struct cache_deferred_req *req, | |
149 | int too_many); | |
150 | }; | |
151 | ||
7715cde8 N |
152 | /* |
153 | * timestamps kept in the cache are expressed in seconds | |
154 | * since boot. This is the best for measuring differences in | |
155 | * real time. | |
156 | */ | |
157 | static inline time_t seconds_since_boot(void) | |
158 | { | |
159 | struct timespec boot; | |
160 | getboottime(&boot); | |
161 | return get_seconds() - boot.tv_sec; | |
162 | } | |
163 | ||
164 | static inline time_t convert_to_wallclock(time_t sinceboot) | |
165 | { | |
166 | struct timespec boot; | |
167 | getboottime(&boot); | |
168 | return boot.tv_sec + sinceboot; | |
169 | } | |
7d317f2c | 170 | |
8854e82d TM |
171 | extern const struct file_operations cache_file_operations_pipefs; |
172 | extern const struct file_operations content_file_operations_pipefs; | |
173 | extern const struct file_operations cache_flush_operations_pipefs; | |
174 | ||
15a5f6bd N |
175 | extern struct cache_head * |
176 | sunrpc_cache_lookup(struct cache_detail *detail, | |
177 | struct cache_head *key, int hash); | |
178 | extern struct cache_head * | |
179 | sunrpc_cache_update(struct cache_detail *detail, | |
180 | struct cache_head *new, struct cache_head *old, int hash); | |
181 | ||
bc74b4f5 | 182 | extern int |
21cd1254 | 183 | sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h); |
bc74b4f5 | 184 | |
1da177e4 | 185 | |
1da177e4 LT |
186 | extern void cache_clean_deferred(void *owner); |
187 | ||
188 | static inline struct cache_head *cache_get(struct cache_head *h) | |
189 | { | |
baab935f | 190 | kref_get(&h->ref); |
1da177e4 LT |
191 | return h; |
192 | } | |
193 | ||
194 | ||
baab935f | 195 | static inline void cache_put(struct cache_head *h, struct cache_detail *cd) |
1da177e4 | 196 | { |
baab935f | 197 | if (atomic_read(&h->ref.refcount) <= 2 && |
1da177e4 LT |
198 | h->expiry_time < cd->nextcheck) |
199 | cd->nextcheck = h->expiry_time; | |
baab935f | 200 | kref_put(&h->ref, cd->cache_put); |
1da177e4 LT |
201 | } |
202 | ||
7715cde8 | 203 | static inline int cache_is_expired(struct cache_detail *detail, struct cache_head *h) |
7b2b1fee | 204 | { |
7715cde8 N |
205 | return (h->expiry_time < seconds_since_boot()) || |
206 | (detail->flush_time > h->last_refresh); | |
7b2b1fee GB |
207 | } |
208 | ||
1da177e4 LT |
209 | extern int cache_check(struct cache_detail *detail, |
210 | struct cache_head *h, struct cache_req *rqstp); | |
211 | extern void cache_flush(void); | |
212 | extern void cache_purge(struct cache_detail *detail); | |
213 | #define NEVER (0x7FFFFFFF) | |
8eab945c | 214 | extern void __init cache_initialize(void); |
593ce16b | 215 | extern int cache_register_net(struct cache_detail *cd, struct net *net); |
593ce16b | 216 | extern void cache_unregister_net(struct cache_detail *cd, struct net *net); |
1da177e4 | 217 | |
0a402d5a SK |
218 | extern struct cache_detail *cache_create_net(struct cache_detail *tmpl, struct net *net); |
219 | extern void cache_destroy_net(struct cache_detail *cd, struct net *net); | |
220 | ||
820f9442 SK |
221 | extern void sunrpc_init_cache_detail(struct cache_detail *cd); |
222 | extern void sunrpc_destroy_cache_detail(struct cache_detail *cd); | |
8854e82d | 223 | extern int sunrpc_cache_register_pipefs(struct dentry *parent, const char *, |
64f1426f | 224 | umode_t, struct cache_detail *); |
8854e82d TM |
225 | extern void sunrpc_cache_unregister_pipefs(struct cache_detail *); |
226 | ||
1da177e4 LT |
227 | extern void qword_add(char **bpp, int *lp, char *str); |
228 | extern void qword_addhex(char **bpp, int *lp, char *buf, int blen); | |
229 | extern int qword_get(char **bpp, char *dest, int bufsize); | |
230 | ||
231 | static inline int get_int(char **bpp, int *anint) | |
232 | { | |
233 | char buf[50]; | |
621eb19c BF |
234 | char *ep; |
235 | int rv; | |
d9c2ede6 EZ |
236 | int len = qword_get(bpp, buf, sizeof(buf)); |
237 | ||
238 | if (len < 0) | |
239 | return -EINVAL; | |
240 | if (len == 0) | |
241 | return -ENOENT; | |
242 | ||
621eb19c BF |
243 | rv = simple_strtol(buf, &ep, 0); |
244 | if (*ep) | |
d9c2ede6 EZ |
245 | return -EINVAL; |
246 | ||
621eb19c | 247 | *anint = rv; |
1da177e4 LT |
248 | return 0; |
249 | } | |
250 | ||
a007c4c3 BF |
251 | static inline int get_uint(char **bpp, unsigned int *anint) |
252 | { | |
253 | char buf[50]; | |
254 | int len = qword_get(bpp, buf, sizeof(buf)); | |
255 | ||
256 | if (len < 0) | |
257 | return -EINVAL; | |
258 | if (len == 0) | |
259 | return -ENOENT; | |
260 | ||
261 | if (kstrtouint(buf, 0, anint)) | |
262 | return -EINVAL; | |
263 | ||
264 | return 0; | |
265 | } | |
266 | ||
1da177e4 LT |
267 | static inline time_t get_expiry(char **bpp) |
268 | { | |
269 | int rv; | |
c5b29f88 N |
270 | struct timespec boot; |
271 | ||
1da177e4 LT |
272 | if (get_int(bpp, &rv)) |
273 | return 0; | |
274 | if (rv < 0) | |
275 | return 0; | |
c5b29f88 N |
276 | getboottime(&boot); |
277 | return rv - boot.tv_sec; | |
1da177e4 LT |
278 | } |
279 | ||
280 | #endif /* _LINUX_SUNRPC_CACHE_H_ */ |