0 a4()P@7 LZ7File not found.  |OȾ$K/* 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 */ #ifndef _LINUX_SUNRPC_CACHE_H_ #define _LINUX_SUNRPC_CACHE_H_ #include #include #include #include #include /* * 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 *); 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 queue; 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)(st