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 <[email protected]> 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/kref.h> 17 #include <linux/slab.h> 18 #include <linux/atomic.h> 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 * 38 * Entries have a ref count and a 'hashed' flag which counts the existence 39 * in the hash table. 40 * We only expire entries when refcount is zero. 41 * Existence in the cache is counted the refcount. 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 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. 55 */ 56 struct kref ref; 57 unsigned long flags; 58 }; 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 */ 63 64 #define CACHE_NEW_EXPIRY 120 /* keep new things pending confirmation for 120 seconds */ 65 66 struct cache_detail_procfs { 67 struct proc_dir_entry *proc_ent; 68 struct proc_dir_entry *flush_ent, *channel_ent, *content_ent; 69 }; 70 71 struct cache_detail_pipefs { 72 struct dentry *dir; 73 }; 74 75 struct cache_detail { 76 struct module * owner; 77 int hash_size; 78 struct hlist_head * hash_table; 79 rwlock_t hash_lock; 80 81 atomic_t inuse; /* active user-space update or lookup */ 82 83 char *name; 84 void (*cache_put)(struct kref *); 85 86 int (*cache_upcall)(struct cache_detail *, 87 struct cache_head *); 88 89 void (*cache_request)(struct cache_detail *cd, 90 struct cache_head *ch, 91 char **bpp, int *blen); 92 93 int (*cache_parse)(struct cache_detail *, 94 char *buf, int len); 95 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, 100 int has_died); 101 102 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); 106 107 /* fields below this comment are for internal use 108 * and should not be touched by cache owners 109 */ 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 114 * than this. 115 */ 116 struct list_head others; 117 time_t nextcheck; 118 int entries; 119 120 /* fields for communication over channel */ 121 struct list_head queue; 122 123 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 */ 126 127 union { 128 struct cache_detail_procfs procfs; 129 struct cache_detail_pipefs pipefs; 130 } u; 131 struct net *net; 132 }; 133 134 135 /* this must be embedded in any request structure that 136 * identifies an object that will want a callback on 137 * a cache fill 138 */ 139 struct cache_req { 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. 143 */ 144 }; 145 /* this must be embedded in a deferred_request that is being 146 * delayed awaiting cache-fill 147 */ 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, 155 int too_many); 156 }; 157 158 /* 159 * timestamps kept in the cache are expressed in seconds 160 * since boot. This is the best for measuring differences in 161 * real time. 162 */ 163 static inline time_t seconds_since_boot(void) 164 { 165 struct timespec boot; 166 getboottime(&boot); 167 return get_seconds() - boot.tv_sec; 168 } 169 170 static inline time_t convert_to_wallclock(time_t sinceboot) 171 { 172 struct timespec boot; 173 getboottime(&boot); 174 return boot.tv_sec + sinceboot; 175 } 176 177 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; 180 181 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); 187 188 extern int 189 sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h); 190 191 192 extern void cache_clean_deferred(void *owner); 193 194 static inline struct cache_head *cache_get(struct cache_head *h) 195 { 196 kref_get(&h->ref); 197 return h; 198 } 199 200 201 static inline void cache_put(struct cache_head *h, struct cache_detail *cd) 202 { 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); 207 } 208 209 static inline int cache_is_expired(struct cache_detail *detail, struct cache_head *h) 210 { 211 return (h->expiry_time < seconds_since_boot()) || 212 (detail->flush_time >= h->last_refresh); 213 } 214 215 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); 223 224 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); 226 227 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 *); 232 233 /* 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); 237 238 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); 241 242 static inline int get_int(char **bpp, int *anint) 243 { 244 char buf[50]; 245 char *ep; 246 int rv; 247 int len = qword_get(bpp, buf, sizeof(buf)); 248 249 if (len < 0) 250 return -EINVAL; 251 if (len == 0) 252 return -ENOENT; 253 254 rv = simple_strtol(buf, &ep, 0); 255 if (*ep) 256 return -EINVAL; 257 258 *anint = rv; 259 return 0; 260 } 261 262 static inline int get_uint(char **bpp, unsigned int *anint) 263 { 264 char buf[50]; 265 int len = qword_get(bpp, buf, sizeof(buf)); 266 267 if (len < 0) 268 return -EINVAL; 269 if (len == 0) 270 return -ENOENT; 271 272 if (kstrtouint(buf, 0, anint)) 273 return -EINVAL; 274 275 return 0; 276 } 277 278 static inline int get_time(char **bpp, time_t *time) 279 { 280 char buf[50]; 281 long long ll; 282 int len = qword_get(bpp, buf, sizeof(buf)); 283 284 if (len < 0) 285 return -EINVAL; 286 if (len == 0) 287 return -ENOENT; 288 289 if (kstrtoll(buf, 0, &ll)) 290 return -EINVAL; 291 292 *time = (time_t)ll; 293 return 0; 294 } 295 296 static inline time_t get_expiry(char **bpp) 297 { 298 time_t rv; 299 struct timespec boot; 300 301 if (get_time(bpp, &rv)) 302 return 0; 303 if (rv < 0) 304 return 0; 305 getboottime(&boot); 306 return rv - boot.tv_sec; 307 } 308 309 #endif /* _LINUX_SUNRPC_CACHE_H_ */ 310