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

/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * 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>
 */

#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;
	spinlock_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);
	void			(*flush)(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		writers;		/* how many time is /channel open */
	time_t			last_close;		/* if no writers, when did last close */
	time_t			last_warn;		/* when we last warned about no writers */

	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_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_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
ddc64d0a	1	/* SPDX-License-Identifier: GPL-2.0-only */
1da177e4 LT	2	/*
	3	* include/linux/sunrpc/cache.h
	4	*
	5	* Generic code for various authentication-related caches
	6	* used by sunrpc clients and servers.
	7	*
	8	* Copyright (C) 2002 Neil Brown <neilb@cse.unsw.edu.au>
1da177e4 LT	9	*/
	10
	11	#ifndef _LINUX_SUNRPC_CACHE_H_
	12	#define _LINUX_SUNRPC_CACHE_H_
	13
57cc7215	14	#include <linux/kref.h>
1da177e4	15	#include <linux/slab.h>
60063497	16	#include <linux/atomic.h>
1da177e4 LT	17	#include <linux/proc_fs.h>
	18
	19	/*
	20	* Each cache requires:
	21	* - A 'struct cache_detail' which contains information specific to the cache
	22	* for common code to use.
	23	* - An item structure that must contain a "struct cache_head"
	24	* - A lookup function defined using DefineCacheLookup
	25	* - A 'put' function that can release a cache item. It will only
	26	* be called after cache_put has succeed, so there are guarantee
	27	* to be no references.
	28	* - A function to calculate a hash of an item's key.
	29	*
	30	* as well as assorted code fragments (e.g. compare keys) and numbers
	31	* (e.g. hash size, goal_age, etc).
	32	*
	33	* Each cache must be registered so that it can be cleaned regularly.
	34	* When the cache is unregistered, it is flushed completely.
	35	*
25985edc	36	* Entries have a ref count and a 'hashed' flag which counts the existence
1da177e4 LT	37	* in the hash table.
1da177e4 LT	38	* We only expire entries when refcount is zero.
25985edc	39	* Existence in the cache is counted the refcount.
1da177e4 LT	40	*/
	41
	42	/* Every cache item has a common header that is used
	43	* for expiring and refreshing entries.
	44	*
	45	*/
	46	struct cache_head {
129e5824	47	struct hlist_node cache_list;
1da177e4	48	time_t expiry_time; /* After time time, don't use the data */
77862036 NB	49	time_t last_refresh; /* If CACHE_PENDING, this is when upcall was
	50	* sent, else this is when update was
	51	* received, though it is alway set to
	52	* be after ->flush_time.
1da177e4	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
	64	struct cache_detail {
f35279d3	65	struct module * owner;
1da177e4	66	int hash_size;
129e5824	67	struct hlist_head * hash_table;
1863d77f	68	spinlock_t hash_lock;
1da177e4	69
1da177e4	70	char *name;
baab935f	71	void (cache_put)(struct kref );
1da177e4	72
bc74b4f5 TM	73	int (cache_upcall)(struct cache_detail ,
	74	struct cache_head *);
	75
73fb847a SK	76	void (cache_request)(struct cache_detail cd,
	77	struct cache_head *ch,
	78	char *bpp, int blen);
	79
1da177e4 LT	80	int (cache_parse)(struct cache_detail ,
	81	char *buf, int len);
	82
	83	int (cache_show)(struct seq_file m,
	84	struct cache_detail *cd,
	85	struct cache_head *h);
2da8ca26 TM	86	void (warn_no_listener)(struct cache_detail cd,
2da8ca26 TM	87	int has_died);
1da177e4	88
15a5f6bd	89	struct cache_head * (*alloc)(void);
f69d6d8e	90	void (*flush)(void);
15a5f6bd N	91	int (match)(struct cache_head orig, struct cache_head *new);
	92	void (init)(struct cache_head orig, struct cache_head *new);
	93	void (update)(struct cache_head orig, struct cache_head *new);
	94
1da177e4 LT	95	/* fields below this comment are for internal use
	96	* and should not be touched by cache owners
	97	*/
77862036 NB	98	time_t flush_time; /* flush all cache items with
	99	* last_refresh at or earlier
	100	* than this. last_refresh
	101	* is never set at or earlier
	102	* than this.
	103	*/
1da177e4 LT	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	110
64a38e84 DW	111	atomic_t writers; /* how many time is /channel open */
	112	time_t last_close; /* if no writers, when did last close */
	113	time_t last_warn; /* when we last warned about no writers */
173912a6 TM	114
173912a6 TM	115	union {
863d7d9c KM	116	struct proc_dir_entry *procfs;
	117	struct dentry *pipefs;
	118	};
0a402d5a	119	struct net *net;
1da177e4 LT	120	};
	121
	122
	123	/* this must be embedded in any request structure that
	124	* identifies an object that will want a callback on
	125	* a cache fill
	126	*/
	127	struct cache_req {
	128	struct cache_deferred_req (defer)(struct cache_req *req);
f16b6e8d N	129	int thread_wait; /* How long (jiffies) we can block the
	130	* current thread to wait for updates.
	131	*/
1da177e4 LT	132	};
	133	/* this must be embedded in a deferred_request that is being
	134	* delayed awaiting cache-fill
	135	*/
	136	struct cache_deferred_req {
11174492	137	struct hlist_node hash; /* on hash chain */
1da177e4 LT	138	struct list_head recent; /* on fifo */
1da177e4 LT	139	struct cache_head item; / cache item we wait on */
1da177e4 LT	140	void owner; / we might need to discard all defered requests
	141	* owned by someone */
	142	void (revisit)(struct cache_deferred_req req,
	143	int too_many);
	144	};
	145
7715cde8 N	146	/*
	147	* timestamps kept in the cache are expressed in seconds
	148	* since boot. This is the best for measuring differences in
	149	* real time.
	150	*/
	151	static inline time_t seconds_since_boot(void)
	152	{
	153	struct timespec boot;
	154	getboottime(&boot);
	155	return get_seconds() - boot.tv_sec;
	156	}
	157
	158	static inline time_t convert_to_wallclock(time_t sinceboot)
	159	{
	160	struct timespec boot;
	161	getboottime(&boot);
	162	return boot.tv_sec + sinceboot;
	163	}
7d317f2c	164
8854e82d TM	165	extern const struct file_operations cache_file_operations_pipefs;
	166	extern const struct file_operations content_file_operations_pipefs;
	167	extern const struct file_operations cache_flush_operations_pipefs;
	168
ae74136b TM	169	extern struct cache_head *
	170	sunrpc_cache_lookup_rcu(struct cache_detail *detail,
	171	struct cache_head *key, int hash);
15a5f6bd	172	extern struct cache_head *
15a5f6bd N	173	sunrpc_cache_update(struct cache_detail *detail,
	174	struct cache_head new, struct cache_head old, int hash);
	175
bc74b4f5	176	extern int
21cd1254	177	sunrpc_cache_pipe_upcall(struct cache_detail detail, struct cache_head h);
bc74b4f5	178
1da177e4	179
1da177e4 LT	180	extern void cache_clean_deferred(void *owner);
	181
	182	static inline struct cache_head cache_get(struct cache_head h)
	183	{
baab935f	184	kref_get(&h->ref);
1da177e4 LT	185	return h;
	186	}
	187
ae74136b TM	188	static inline struct cache_head cache_get_rcu(struct cache_head h)
	189	{
	190	if (kref_get_unless_zero(&h->ref))
	191	return h;
	192	return NULL;
	193	}
1da177e4	194
baab935f	195	static inline void cache_put(struct cache_head h, struct cache_detail cd)
1da177e4	196	{
2c935bc5	197	if (kref_read(&h->ref) <= 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
d6fc8821	203	static inline bool cache_is_expired(struct cache_detail detail, struct cache_head h)
7b2b1fee	204	{
d6fc8821 KM	205	if (!test_bit(CACHE_VALID, &h->flags))
	206	return false;
	207
7715cde8	208	return (h->expiry_time < seconds_since_boot()) \|\|
77862036	209	(detail->flush_time >= h->last_refresh);
7b2b1fee GB	210	}
7b2b1fee GB	211
1da177e4 LT	212	extern int cache_check(struct cache_detail *detail,
	213	struct cache_head h, struct cache_req rqstp);
	214	extern void cache_flush(void);
	215	extern void cache_purge(struct cache_detail *detail);
	216	#define NEVER (0x7FFFFFFF)
8eab945c	217	extern void __init cache_initialize(void);
593ce16b	218	extern int cache_register_net(struct cache_detail cd, struct net net);
593ce16b	219	extern void cache_unregister_net(struct cache_detail cd, struct net net);
1da177e4	220
d34971a6	221	extern struct cache_detail cache_create_net(const struct cache_detail tmpl, struct net *net);
0a402d5a SK	222	extern void cache_destroy_net(struct cache_detail cd, struct net net);
0a402d5a SK	223
820f9442 SK	224	extern void sunrpc_init_cache_detail(struct cache_detail *cd);
820f9442 SK	225	extern void sunrpc_destroy_cache_detail(struct cache_detail *cd);
8854e82d	226	extern int sunrpc_cache_register_pipefs(struct dentry parent, const char ,
64f1426f	227	umode_t, struct cache_detail *);
8854e82d	228	extern void sunrpc_cache_unregister_pipefs(struct cache_detail *);
2b477c00	229	extern void sunrpc_cache_unhash(struct cache_detail , struct cache_head );
8854e82d	230
c8c081b7	231	/* Must store cache_detail in seq_file->private if using next three functions */
ae74136b TM	232	extern void cache_seq_start_rcu(struct seq_file file, loff_t *pos);
	233	extern void cache_seq_next_rcu(struct seq_file file, void p, loff_t pos);
	234	extern void cache_seq_stop_rcu(struct seq_file file, void p);
c8c081b7	235
1da177e4 LT	236	extern void qword_add(char *bpp, int lp, char *str);
	237	extern void qword_addhex(char *bpp, int lp, char *buf, int blen);
	238	extern int qword_get(char *bpp, char dest, int bufsize);
	239
	240	static inline int get_int(char *bpp, int anint)
	241	{
	242	char buf[50];
621eb19c BF	243	char *ep;
621eb19c BF	244	int rv;
d9c2ede6 EZ	245	int len = qword_get(bpp, buf, sizeof(buf));
	246
	247	if (len < 0)
	248	return -EINVAL;
	249	if (len == 0)
	250	return -ENOENT;
	251
621eb19c BF	252	rv = simple_strtol(buf, &ep, 0);
621eb19c BF	253	if (*ep)
d9c2ede6 EZ	254	return -EINVAL;
d9c2ede6 EZ	255
621eb19c	256	*anint = rv;
1da177e4 LT	257	return 0;
	258	}
	259
a007c4c3 BF	260	static inline int get_uint(char *bpp, unsigned int anint)
	261	{
	262	char buf[50];
	263	int len = qword_get(bpp, buf, sizeof(buf));
	264
	265	if (len < 0)
	266	return -EINVAL;
	267	if (len == 0)
	268	return -ENOENT;
	269
	270	if (kstrtouint(buf, 0, anint))
	271	return -EINVAL;
	272
	273	return 0;
	274	}
	275
2f74f972 HJ	276	static inline int get_time(char *bpp, time_t time)
	277	{
	278	char buf[50];
	279	long long ll;
	280	int len = qword_get(bpp, buf, sizeof(buf));
	281
	282	if (len < 0)
	283	return -EINVAL;
	284	if (len == 0)
	285	return -ENOENT;
	286
	287	if (kstrtoll(buf, 0, &ll))
	288	return -EINVAL;
	289
	290	*time = (time_t)ll;
	291	return 0;
	292	}
	293
1da177e4 LT	294	static inline time_t get_expiry(char **bpp)
1da177e4 LT	295	{
2f74f972	296	time_t rv;
c5b29f88 N	297	struct timespec boot;
c5b29f88 N	298
2f74f972	299	if (get_time(bpp, &rv))
1da177e4 LT	300	return 0;
	301	if (rv < 0)
	302	return 0;
c5b29f88 N	303	getboottime(&boot);
c5b29f88 N	304	return rv - boot.tv_sec;
1da177e4 LT	305	}
	306
	307	#endif /* _LINUX_SUNRPC_CACHE_H_ */