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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#ifndef _LINUX_SUNRPC_CACHE_H_#define _LINUX_SUNRPC_CACHE_H_
#include <linux/kref.h>#include <linux/slab.h>#include <linux/atomic.h>#include <linux/kstrtox.h>#include <linux/proc_fs.h>#include <linux/wait.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; time64_t expiry_time; /* After time expiry_time, don't use * the data */ time64_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;};
/* cache_head.flags */enum { CACHE_VALID, /* Entry contains valid data */ CACHE_NEGATIVE, /* Negative entry - there is no match for the key */ CACHE_PENDING, /* An upcall has been sent but no reply received yet*/ CACHE_CLEANED, /* 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 *);
int (*cache_notify)(struct cache_detail *cd, struct cache_head *h);
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 */ time64_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; time64_t nextcheck; int entries;
/* fields for communication over channel */ struct list_head requests; struct list_head readers; spinlock_t queue_lock; wait_queue_head_t queue_wait; u64 next_seqno;
atomic_t writers; /* how many time is /channel open */ time64_t last_close; /* if no writers, when did last close */ time64_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); unsigned long 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. * This reimplemnts ktime_get_boottime_seconds() in a slightly * faster but less accurate way. When we end up converting * back to wallclock (CLOCK_REALTIME), that error often * cancels out during the reverse operation. */static inline time64_t seconds_since_boot(void){ struct timespec64 boot; getboottime64(&boot); return ktime_get_real_seconds() - boot.tv_sec;}
static inline time64_t convert_to_wallclock(time64_t sinceboot){ struct timespec64 boot; getboottime64(&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 intsunrpc_cache_upcall(struct cache_detail *detail, struct cache_head *h);extern intsunrpc_cache_upcall_warn(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 (h->expiry_time < seconds_since_boot()) return true; if (!test_bit(CACHE_VALID, &h->flags)) return false; return detail->flush_time >= h->last_refresh;}
extern int cache_check_rcu(struct cache_detail *detail, struct cache_head *h, struct cache_req *rqstp);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 *);
int sunrpc_cache_requests_count(struct cache_detail *cd);int sunrpc_cache_requests_snapshot(struct cache_detail *cd, struct cache_head **items, u64 *seqnos, int max, u64 min_seqno);int sunrpc_cache_notify(struct cache_detail *cd, struct cache_head *h, u32 cache_type);
/* 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, time64_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 = ll; return 0;}
static inline int get_expiry(char **bpp, time64_t *rvp){ int error; struct timespec64 boot;
error = get_time(bpp, rvp); if (error) return error;
getboottime64(&boot); (*rvp) -= boot.tv_sec; return 0;}
#endif /* _LINUX_SUNRPC_CACHE_H_ */