[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 cache_head * next;
	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
					 */
	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_procfs {
	struct proc_dir_entry	*proc_ent;
	struct proc_dir_entry   *flush_ent, *channel_ent, *content_ent;
};

struct cache_detail_pipefs {
	struct dentry *dir;
};

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

	atomic_t		inuse; /* active user-space update or lookup */

	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
							 * 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 cache_detail_procfs procfs;
		struct cache_detail_pipefs pipefs;
	} u;
	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(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 void cache_put(struct cache_head *h, struct cache_detail *cd)
{
	if (atomic_read(&h->ref.refcount) <= 2 &&
	    h->expiry_time < cd->nextcheck)
		cd->nextcheck = h->expiry_time;
	kref_put(&h->ref, cd->cache_put);
}

static inline int cache_is_expired(struct cache_detail *detail, struct cache_head *h)
{
	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(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 *);

/* 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 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 {
	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,
2da8ca26 TM	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 */
1da177e4 LT	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)
1da177e4 LT	199	cd->nextcheck = h->expiry_time;
baab935f	200	kref_put(&h->ref, cd->cache_put);
1da177e4 LT	201	}
1da177e4 LT	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()) \|\|
7715cde8 N	206	(detail->flush_time > h->last_refresh);
7b2b1fee GB	207	}
7b2b1fee GB	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);
820f9442 SK	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 *);
8854e82d TM	226
c8c081b7 KM	227	/* Must store cache_detail in seq_file->private if using next three functions */
	228	extern void cache_seq_start(struct seq_file file, loff_t *pos);
	229	extern void cache_seq_next(struct seq_file file, void p, loff_t pos);
	230	extern void cache_seq_stop(struct seq_file file, void p);
	231
1da177e4 LT	232	extern void qword_add(char *bpp, int lp, char *str);
	233	extern void qword_addhex(char *bpp, int lp, char *buf, int blen);
	234	extern int qword_get(char *bpp, char dest, int bufsize);
	235
	236	static inline int get_int(char *bpp, int anint)
	237	{
	238	char buf[50];
621eb19c BF	239	char *ep;
621eb19c BF	240	int rv;
d9c2ede6 EZ	241	int len = qword_get(bpp, buf, sizeof(buf));
	242
	243	if (len < 0)
	244	return -EINVAL;
	245	if (len == 0)
	246	return -ENOENT;
	247
621eb19c BF	248	rv = simple_strtol(buf, &ep, 0);
621eb19c BF	249	if (*ep)
d9c2ede6 EZ	250	return -EINVAL;
d9c2ede6 EZ	251
621eb19c	252	*anint = rv;
1da177e4 LT	253	return 0;
	254	}
	255
a007c4c3 BF	256	static inline int get_uint(char *bpp, unsigned int anint)
	257	{
	258	char buf[50];
	259	int len = qword_get(bpp, buf, sizeof(buf));
	260
	261	if (len < 0)
	262	return -EINVAL;
	263	if (len == 0)
	264	return -ENOENT;
	265
	266	if (kstrtouint(buf, 0, anint))
	267	return -EINVAL;
	268
	269	return 0;
	270	}
	271
2f74f972 HJ	272	static inline int get_time(char *bpp, time_t time)
	273	{
	274	char buf[50];
	275	long long ll;
	276	int len = qword_get(bpp, buf, sizeof(buf));
	277
	278	if (len < 0)
	279	return -EINVAL;
	280	if (len == 0)
	281	return -ENOENT;
	282
	283	if (kstrtoll(buf, 0, &ll))
	284	return -EINVAL;
	285
	286	*time = (time_t)ll;
	287	return 0;
	288	}
	289
1da177e4 LT	290	static inline time_t get_expiry(char **bpp)
1da177e4 LT	291	{
2f74f972	292	time_t rv;
c5b29f88 N	293	struct timespec boot;
c5b29f88 N	294
2f74f972	295	if (get_time(bpp, &rv))
1da177e4 LT	296	return 0;
	297	if (rv < 0)
	298	return 0;
c5b29f88 N	299	getboottime(&boot);
c5b29f88 N	300	return rv - boot.tv_sec;
1da177e4 LT	301	}
	302
	303	#endif /* _LINUX_SUNRPC_CACHE_H_ */