[linux-2.6-block.git] / include / linux / sunrpc / cache.h

/*
 * include/linux/sunrpc/cache.h
 *
 * Generic code for various authentication-related caches
 * used by sunrpc clients and servers.
 *
 * Copyright (C) 2002 Neil Brown <neilb@cse.unsw.edu.au>
 *
 * Released under terms in GPL version 2.  See COPYING.
 *
 */

#ifndef _LINUX_SUNRPC_CACHE_H_
#define _LINUX_SUNRPC_CACHE_H_

#include <linux/kref.h>
#include <linux/slab.h>
#include <linux/atomic.h>
#include <linux/proc_fs.h>

/*
 * Each cache requires:
 *  - A 'struct cache_detail' which contains information specific to the cache
 *    for common code to use.
 *  - An item structure that must contain a "struct cache_head"
 *  - A lookup function defined using DefineCacheLookup
 *  - A 'put' function that can release a cache item. It will only
 *    be called after cache_put has succeed, so there are guarantee
 *    to be no references.
 *  - A function to calculate a hash of an item's key.
 *
 * as well as assorted code fragments (e.g. compare keys) and numbers
 * (e.g. hash size, goal_age, etc).
 *
 * Each cache must be registered so that it can be cleaned regularly.
 * When the cache is unregistered, it is flushed completely.
 *
 * Entries have a ref count and a 'hashed' flag which counts the existence
 * in the hash table.
 * We only expire entries when refcount is zero.
 * Existence in the cache is counted  the refcount.
 */

/* Every cache item has a common header that is used
 * for expiring and refreshing entries.
 * 
 */
struct cache_head {
	struct hlist_node	cache_list;
	time_t		expiry_time;	/* After time time, don't use the data */
	time_t		last_refresh;   /* If CACHE_PENDING, this is when upcall was
					 * sent, else this is when update was
					 * received, though it is alway set to
					 * be *after* ->flush_time.
					 */
	struct kref	ref;
	unsigned long	flags;
};
#define	CACHE_VALID	0	/* Entry contains valid data */
#define	CACHE_NEGATIVE	1	/* Negative entry - there is no match for the key */
#define	CACHE_PENDING	2	/* An upcall has been sent but no reply received yet*/
#define	CACHE_CLEANED	3	/* Entry has been cleaned from cache */

#define	CACHE_NEW_EXPIRY 120	/* keep new things pending confirmation for 120 seconds */

struct cache_detail {
	struct module *		owner;
	int			hash_size;
	struct hlist_head *	hash_table;
	rwlock_t		hash_lock;

	char			*name;
	void			(*cache_put)(struct kref *);

	int			(*cache_upcall)(struct cache_detail *,
						struct cache_head *);

	void			(*cache_request)(struct cache_detail *cd,
						 struct cache_head *ch,
						 char **bpp, int *blen);

	int			(*cache_parse)(struct cache_detail *,
					       char *buf, int len);

	int			(*cache_show)(struct seq_file *m,
					      struct cache_detail *cd,
					      struct cache_head *h);
	void			(*warn_no_listener)(struct cache_detail *cd,
					      int has_died);

	struct cache_head *	(*alloc)(void);
	int			(*match)(struct cache_head *orig, struct cache_head *new);
	void			(*init)(struct cache_head *orig, struct cache_head *new);
	void			(*update)(struct cache_head *orig, struct cache_head *new);

	/* fields below this comment are for internal use
	 * and should not be touched by cache owners
	 */
	time_t			flush_time;		/* flush all cache items with
							 * last_refresh at or earlier
							 * than this.  last_refresh
							 * is never set at or earlier
							 * than this.
							 */
	struct list_head	others;
	time_t			nextcheck;
	int			entries;

	/* fields for communication over channel */
	struct list_head	queue;

	atomic_t		readers;		/* how many time is /chennel open */
	time_t			last_close;		/* if no readers, when did last close */
	time_t			last_warn;		/* when we last warned about no readers */

	union {
		struct proc_dir_entry	*procfs;
		struct dentry		*pipefs;
	};
	struct net		*net;
};


/* this must be embedded in any request structure that
 * identifies an object that will want a callback on
 * a cache fill
 */
struct cache_req {
	struct cache_deferred_req *(*defer)(struct cache_req *req);
	int thread_wait;  /* How long (jiffies) we can block the
			   * current thread to wait for updates.
			   */
};
/* this must be embedded in a deferred_request that is being
 * delayed awaiting cache-fill
 */
struct cache_deferred_req {
	struct hlist_node	hash;	/* on hash chain */
	struct list_head	recent; /* on fifo */
	struct cache_head	*item;  /* cache item we wait on */
	void			*owner; /* we might need to discard all defered requests
					 * owned by someone */
	void			(*revisit)(struct cache_deferred_req *req,
					   int too_many);
};

/*
 * timestamps kept in the cache are expressed in seconds
 * since boot.  This is the best for measuring differences in
 * real time.
 */
static inline time_t seconds_since_boot(void)
{
	struct timespec boot;
	getboottime(&boot);
	return get_seconds() - boot.tv_sec;
}

static inline time_t convert_to_wallclock(time_t sinceboot)
{
	struct timespec boot;
	getboottime(&boot);
	return boot.tv_sec + sinceboot;
}

extern const struct file_operations cache_file_operations_pipefs;
extern const struct file_operations content_file_operations_pipefs;
extern const struct file_operations cache_flush_operations_pipefs;

extern struct cache_head *
sunrpc_cache_lookup_rcu(struct cache_detail *detail,
			struct cache_head *key, int hash);
extern struct cache_head *
sunrpc_cache_lookup(struct cache_detail *detail,
		    struct cache_head *key, int hash);
extern struct cache_head *
sunrpc_cache_update(struct cache_detail *detail,
		    struct cache_head *new, struct cache_head *old, int hash);

extern int
sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h);


extern void cache_clean_deferred(void *owner);

static inline struct cache_head  *cache_get(struct cache_head *h)
{
	kref_get(&h->ref);
	return h;
}

static inline struct cache_head  *cache_get_rcu(struct cache_head *h)
{
	if (kref_get_unless_zero(&h->ref))
		return h;
	return NULL;
}

static inline void cache_put(struct cache_head *h, struct cache_detail *cd)
{
	if (kref_read(&h->ref) <= 2 &&
	    h->expiry_time < cd->nextcheck)
		cd->nextcheck = h->expiry_time;
	kref_put(&h->ref, cd->cache_put);
}

static inline bool cache_is_expired(struct cache_detail *detail, struct cache_head *h)
{
	if (!test_bit(CACHE_VALID, &h->flags))
		return false;

	return  (h->expiry_time < seconds_since_boot()) ||
		(detail->flush_time >= h->last_refresh);
}

extern int cache_check(struct cache_detail *detail,
		       struct cache_head *h, struct cache_req *rqstp);
extern void cache_flush(void);
extern void cache_purge(struct cache_detail *detail);
#define NEVER (0x7FFFFFFF)
extern void __init cache_initialize(void);
extern int cache_register_net(struct cache_detail *cd, struct net *net);
extern void cache_unregister_net(struct cache_detail *cd, struct net *net);

extern struct cache_detail *cache_create_net(const struct cache_detail *tmpl, struct net *net);
extern void cache_destroy_net(struct cache_detail *cd, struct net *net);

extern void sunrpc_init_cache_detail(struct cache_detail *cd);
extern void sunrpc_destroy_cache_detail(struct cache_detail *cd);
extern int sunrpc_cache_register_pipefs(struct dentry *parent, const char *,
					umode_t, struct cache_detail *);
extern void sunrpc_cache_unregister_pipefs(struct cache_detail *);
extern void sunrpc_cache_unhash(struct cache_detail *, struct cache_head *);

/* Must store cache_detail in seq_file->private if using next three functions */
extern void *cache_seq_start(struct seq_file *file, loff_t *pos);
extern void *cache_seq_next(struct seq_file *file, void *p, loff_t *pos);
extern void cache_seq_stop(struct seq_file *file, void *p);
extern void *cache_seq_start_rcu(struct seq_file *file, loff_t *pos);
extern void *cache_seq_next_rcu(struct seq_file *file, void *p, loff_t *pos);
extern void cache_seq_stop_rcu(struct seq_file *file, void *p);

extern void qword_add(char **bpp, int *lp, char *str);
extern void qword_addhex(char **bpp, int *lp, char *buf, int blen);
extern int qword_get(char **bpp, char *dest, int bufsize);

static inline int get_int(char **bpp, int *anint)
{
	char buf[50];
	char *ep;
	int rv;
	int len = qword_get(bpp, buf, sizeof(buf));

	if (len < 0)
		return -EINVAL;
	if (len == 0)
		return -ENOENT;

	rv = simple_strtol(buf, &ep, 0);
	if (*ep)
		return -EINVAL;

	*anint = rv;
	return 0;
}

static inline int get_uint(char **bpp, unsigned int *anint)
{
	char buf[50];
	int len = qword_get(bpp, buf, sizeof(buf));

	if (len < 0)
		return -EINVAL;
	if (len == 0)
		return -ENOENT;

	if (kstrtouint(buf, 0, anint))
		return -EINVAL;

	return 0;
}

static inline int get_time(char **bpp, time_t *time)
{
	char buf[50];
	long long ll;
	int len = qword_get(bpp, buf, sizeof(buf));

	if (len < 0)
		return -EINVAL;
	if (len == 0)
		return -ENOENT;

	if (kstrtoll(buf, 0, &ll))
		return -EINVAL;

	*time = (time_t)ll;
	return 0;
}

static inline time_t get_expiry(char **bpp)
{
	time_t rv;
	struct timespec boot;

	if (get_time(bpp, &rv))
		return 0;
	if (rv < 0)
		return 0;
	getboottime(&boot);
	return rv - boot.tv_sec;
}

#endif /*  _LINUX_SUNRPC_CACHE_H_ */
Commit	Line	Data
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.
1da177e4 LT	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 {
129e5824	49	struct hlist_node cache_list;
1da177e4	50	time_t expiry_time; /* After time time, don't use the data */
77862036 NB	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.
1da177e4	55	*/
baab935f	56	struct kref ref;
1da177e4 LT	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*/
013920eb	62	#define CACHE_CLEANED 3 /* Entry has been cleaned from cache */
1da177e4 LT	63
	64	#define CACHE_NEW_EXPIRY 120 /* keep new things pending confirmation for 120 seconds */
	65
	66	struct cache_detail {
f35279d3	67	struct module * owner;
1da177e4	68	int hash_size;
129e5824	69	struct hlist_head * hash_table;
1da177e4 LT	70	rwlock_t hash_lock;
1da177e4 LT	71
1da177e4	72	char *name;
baab935f	73	void (cache_put)(struct kref );
1da177e4	74
bc74b4f5 TM	75	int (cache_upcall)(struct cache_detail ,
	76	struct cache_head *);
	77
73fb847a SK	78	void (cache_request)(struct cache_detail cd,
	79	struct cache_head *ch,
	80	char *bpp, int blen);
	81
1da177e4 LT	82	int (cache_parse)(struct cache_detail ,
	83	char *buf, int len);
	84
	85	int (cache_show)(struct seq_file m,
	86	struct cache_detail *cd,
	87	struct cache_head *h);
2da8ca26 TM	88	void (warn_no_listener)(struct cache_detail cd,
2da8ca26 TM	89	int has_died);
1da177e4	90
15a5f6bd N	91	struct cache_head * (*alloc)(void);
	92	int (match)(struct cache_head orig, struct cache_head *new);
	93	void (init)(struct cache_head orig, struct cache_head *new);
	94	void (update)(struct cache_head orig, struct cache_head *new);
	95
1da177e4 LT	96	/* fields below this comment are for internal use
	97	* and should not be touched by cache owners
	98	*/
77862036 NB	99	time_t flush_time; /* flush all cache items with
	100	* last_refresh at or earlier
	101	* than this. last_refresh
	102	* is never set at or earlier
	103	* than this.
	104	*/
1da177e4 LT	105	struct list_head others;
	106	time_t nextcheck;
	107	int entries;
	108
	109	/* fields for communication over channel */
	110	struct list_head queue;
1da177e4 LT	111
	112	atomic_t readers; /* how many time is /chennel open */
	113	time_t last_close; /* if no readers, when did last close */
	114	time_t last_warn; /* when we last warned about no readers */
173912a6 TM	115
173912a6 TM	116	union {
863d7d9c KM	117	struct proc_dir_entry *procfs;
	118	struct dentry *pipefs;
	119	};
0a402d5a	120	struct net *net;
1da177e4 LT	121	};
	122
	123
	124	/* this must be embedded in any request structure that
	125	* identifies an object that will want a callback on
	126	* a cache fill
	127	*/
	128	struct cache_req {
	129	struct cache_deferred_req (defer)(struct cache_req *req);
f16b6e8d N	130	int thread_wait; /* How long (jiffies) we can block the
	131	* current thread to wait for updates.
	132	*/
1da177e4 LT	133	};
	134	/* this must be embedded in a deferred_request that is being
	135	* delayed awaiting cache-fill
	136	*/
	137	struct cache_deferred_req {
11174492	138	struct hlist_node hash; /* on hash chain */
1da177e4 LT	139	struct list_head recent; /* on fifo */
1da177e4 LT	140	struct cache_head item; / cache item we wait on */
1da177e4 LT	141	void owner; / we might need to discard all defered requests
	142	* owned by someone */
	143	void (revisit)(struct cache_deferred_req req,
	144	int too_many);
	145	};
	146
7715cde8 N	147	/*
	148	* timestamps kept in the cache are expressed in seconds
	149	* since boot. This is the best for measuring differences in
	150	* real time.
	151	*/
	152	static inline time_t seconds_since_boot(void)
	153	{
	154	struct timespec boot;
	155	getboottime(&boot);
	156	return get_seconds() - boot.tv_sec;
	157	}
	158
	159	static inline time_t convert_to_wallclock(time_t sinceboot)
	160	{
	161	struct timespec boot;
	162	getboottime(&boot);
	163	return boot.tv_sec + sinceboot;
	164	}
7d317f2c	165
8854e82d TM	166	extern const struct file_operations cache_file_operations_pipefs;
	167	extern const struct file_operations content_file_operations_pipefs;
	168	extern const struct file_operations cache_flush_operations_pipefs;
	169
ae74136b TM	170	extern struct cache_head *
	171	sunrpc_cache_lookup_rcu(struct cache_detail *detail,
	172	struct cache_head *key, int hash);
15a5f6bd N	173	extern struct cache_head *
	174	sunrpc_cache_lookup(struct cache_detail *detail,
	175	struct cache_head *key, int hash);
	176	extern struct cache_head *
	177	sunrpc_cache_update(struct cache_detail *detail,
	178	struct cache_head new, struct cache_head old, int hash);
	179
bc74b4f5	180	extern int
21cd1254	181	sunrpc_cache_pipe_upcall(struct cache_detail detail, struct cache_head h);
bc74b4f5	182
1da177e4	183
1da177e4 LT	184	extern void cache_clean_deferred(void *owner);
	185
	186	static inline struct cache_head cache_get(struct cache_head h)
	187	{
baab935f	188	kref_get(&h->ref);
1da177e4 LT	189	return h;
	190	}
	191
ae74136b TM	192	static inline struct cache_head cache_get_rcu(struct cache_head h)
	193	{
	194	if (kref_get_unless_zero(&h->ref))
	195	return h;
	196	return NULL;
	197	}
1da177e4	198
baab935f	199	static inline void cache_put(struct cache_head h, struct cache_detail cd)
1da177e4	200	{
2c935bc5	201	if (kref_read(&h->ref) <= 2 &&
1da177e4 LT	202	h->expiry_time < cd->nextcheck)
1da177e4 LT	203	cd->nextcheck = h->expiry_time;
baab935f	204	kref_put(&h->ref, cd->cache_put);
1da177e4 LT	205	}
1da177e4 LT	206
d6fc8821	207	static inline bool cache_is_expired(struct cache_detail detail, struct cache_head h)
7b2b1fee	208	{
d6fc8821 KM	209	if (!test_bit(CACHE_VALID, &h->flags))
	210	return false;
	211
7715cde8	212	return (h->expiry_time < seconds_since_boot()) \|\|
77862036	213	(detail->flush_time >= h->last_refresh);
7b2b1fee GB	214	}
7b2b1fee GB	215
1da177e4 LT	216	extern int cache_check(struct cache_detail *detail,
	217	struct cache_head h, struct cache_req rqstp);
	218	extern void cache_flush(void);
	219	extern void cache_purge(struct cache_detail *detail);
	220	#define NEVER (0x7FFFFFFF)
8eab945c	221	extern void __init cache_initialize(void);
593ce16b	222	extern int cache_register_net(struct cache_detail cd, struct net net);
593ce16b	223	extern void cache_unregister_net(struct cache_detail cd, struct net net);
1da177e4	224
d34971a6	225	extern struct cache_detail cache_create_net(const struct cache_detail tmpl, struct net *net);
0a402d5a SK	226	extern void cache_destroy_net(struct cache_detail cd, struct net net);
0a402d5a SK	227
820f9442 SK	228	extern void sunrpc_init_cache_detail(struct cache_detail *cd);
820f9442 SK	229	extern void sunrpc_destroy_cache_detail(struct cache_detail *cd);
8854e82d	230	extern int sunrpc_cache_register_pipefs(struct dentry parent, const char ,
64f1426f	231	umode_t, struct cache_detail *);
8854e82d	232	extern void sunrpc_cache_unregister_pipefs(struct cache_detail *);
2b477c00	233	extern void sunrpc_cache_unhash(struct cache_detail , struct cache_head );
8854e82d	234
c8c081b7 KM	235	/* Must store cache_detail in seq_file->private if using next three functions */
	236	extern void cache_seq_start(struct seq_file file, loff_t *pos);
	237	extern void cache_seq_next(struct seq_file file, void p, loff_t pos);
	238	extern void cache_seq_stop(struct seq_file file, void p);
ae74136b TM	239	extern void cache_seq_start_rcu(struct seq_file file, loff_t *pos);
	240	extern void cache_seq_next_rcu(struct seq_file file, void p, loff_t pos);
	241	extern void cache_seq_stop_rcu(struct seq_file file, void p);
c8c081b7	242
1da177e4 LT	243	extern void qword_add(char *bpp, int lp, char *str);
	244	extern void qword_addhex(char *bpp, int lp, char *buf, int blen);
	245	extern int qword_get(char *bpp, char dest, int bufsize);
	246
	247	static inline int get_int(char *bpp, int anint)
	248	{
	249	char buf[50];
621eb19c BF	250	char *ep;
621eb19c BF	251	int rv;
d9c2ede6 EZ	252	int len = qword_get(bpp, buf, sizeof(buf));
	253
	254	if (len < 0)
	255	return -EINVAL;
	256	if (len == 0)
	257	return -ENOENT;
	258
621eb19c BF	259	rv = simple_strtol(buf, &ep, 0);
621eb19c BF	260	if (*ep)
d9c2ede6 EZ	261	return -EINVAL;
d9c2ede6 EZ	262
621eb19c	263	*anint = rv;
1da177e4 LT	264	return 0;
	265	}
	266
a007c4c3 BF	267	static inline int get_uint(char *bpp, unsigned int anint)
	268	{
	269	char buf[50];
	270	int len = qword_get(bpp, buf, sizeof(buf));
	271
	272	if (len < 0)
	273	return -EINVAL;
	274	if (len == 0)
	275	return -ENOENT;
	276
	277	if (kstrtouint(buf, 0, anint))
	278	return -EINVAL;
	279
	280	return 0;
	281	}
	282
2f74f972 HJ	283	static inline int get_time(char *bpp, time_t time)
	284	{
	285	char buf[50];
	286	long long ll;
	287	int len = qword_get(bpp, buf, sizeof(buf));
	288
	289	if (len < 0)
	290	return -EINVAL;
	291	if (len == 0)
	292	return -ENOENT;
	293
	294	if (kstrtoll(buf, 0, &ll))
	295	return -EINVAL;
	296
	297	*time = (time_t)ll;
	298	return 0;
	299	}
	300
1da177e4 LT	301	static inline time_t get_expiry(char **bpp)
1da177e4 LT	302	{
2f74f972	303	time_t rv;
c5b29f88 N	304	struct timespec boot;
c5b29f88 N	305
2f74f972	306	if (get_time(bpp, &rv))
1da177e4 LT	307	return 0;
	308	if (rv < 0)
	309	return 0;
c5b29f88 N	310	getboottime(&boot);
c5b29f88 N	311	return rv - boot.tv_sec;
1da177e4 LT	312	}
	313
	314	#endif /* _LINUX_SUNRPC_CACHE_H_ */