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315 lines
8.9 KiB
315 lines
8.9 KiB
/* SPDX-License-Identifier: GPL-2.0-only */ |
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/* |
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* include/linux/sunrpc/cache.h |
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* |
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* Generic code for various authentication-related caches |
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* used by sunrpc clients and servers. |
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* |
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* Copyright (C) 2002 Neil Brown <[email protected]> |
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*/ |
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#ifndef _LINUX_SUNRPC_CACHE_H_ |
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#define _LINUX_SUNRPC_CACHE_H_ |
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#include <linux/kref.h> |
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#include <linux/slab.h> |
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#include <linux/atomic.h> |
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#include <linux/proc_fs.h> |
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/* |
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* Each cache requires: |
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* - A 'struct cache_detail' which contains information specific to the cache |
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* for common code to use. |
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* - An item structure that must contain a "struct cache_head" |
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* - A lookup function defined using DefineCacheLookup |
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* - A 'put' function that can release a cache item. It will only |
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* be called after cache_put has succeed, so there are guarantee |
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* to be no references. |
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* - A function to calculate a hash of an item's key. |
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* |
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* as well as assorted code fragments (e.g. compare keys) and numbers |
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* (e.g. hash size, goal_age, etc). |
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* |
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* Each cache must be registered so that it can be cleaned regularly. |
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* When the cache is unregistered, it is flushed completely. |
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* |
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* Entries have a ref count and a 'hashed' flag which counts the existence |
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* in the hash table. |
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* We only expire entries when refcount is zero. |
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* Existence in the cache is counted the refcount. |
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*/ |
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/* Every cache item has a common header that is used |
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* for expiring and refreshing entries. |
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* |
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*/ |
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struct cache_head { |
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struct hlist_node cache_list; |
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time64_t expiry_time; /* After time expiry_time, don't use |
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* the data */ |
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time64_t last_refresh; /* If CACHE_PENDING, this is when upcall was |
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* sent, else this is when update was |
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* received, though it is alway set to |
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* be *after* ->flush_time. |
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*/ |
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struct kref ref; |
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unsigned long flags; |
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}; |
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#define CACHE_VALID 0 /* Entry contains valid data */ |
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#define CACHE_NEGATIVE 1 /* Negative entry - there is no match for the key */ |
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#define CACHE_PENDING 2 /* An upcall has been sent but no reply received yet*/ |
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#define CACHE_CLEANED 3 /* Entry has been cleaned from cache */ |
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#define CACHE_NEW_EXPIRY 120 /* keep new things pending confirmation for 120 seconds */ |
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struct cache_detail { |
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struct module * owner; |
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int hash_size; |
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struct hlist_head * hash_table; |
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spinlock_t hash_lock; |
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char *name; |
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void (*cache_put)(struct kref *); |
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int (*cache_upcall)(struct cache_detail *, |
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struct cache_head *); |
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void (*cache_request)(struct cache_detail *cd, |
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struct cache_head *ch, |
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char **bpp, int *blen); |
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int (*cache_parse)(struct cache_detail *, |
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char *buf, int len); |
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int (*cache_show)(struct seq_file *m, |
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struct cache_detail *cd, |
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struct cache_head *h); |
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void (*warn_no_listener)(struct cache_detail *cd, |
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int has_died); |
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struct cache_head * (*alloc)(void); |
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void (*flush)(void); |
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int (*match)(struct cache_head *orig, struct cache_head *new); |
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void (*init)(struct cache_head *orig, struct cache_head *new); |
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void (*update)(struct cache_head *orig, struct cache_head *new); |
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/* fields below this comment are for internal use |
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* and should not be touched by cache owners |
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*/ |
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time64_t flush_time; /* flush all cache items with |
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* last_refresh at or earlier |
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* than this. last_refresh |
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* is never set at or earlier |
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* than this. |
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*/ |
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struct list_head others; |
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time64_t nextcheck; |
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int entries; |
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/* fields for communication over channel */ |
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struct list_head queue; |
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atomic_t writers; /* how many time is /channel open */ |
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time64_t last_close; /* if no writers, when did last close */ |
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time64_t last_warn; /* when we last warned about no writers */ |
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union { |
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struct proc_dir_entry *procfs; |
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struct dentry *pipefs; |
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}; |
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struct net *net; |
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}; |
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/* this must be embedded in any request structure that |
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* identifies an object that will want a callback on |
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* a cache fill |
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*/ |
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struct cache_req { |
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struct cache_deferred_req *(*defer)(struct cache_req *req); |
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int thread_wait; /* How long (jiffies) we can block the |
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* current thread to wait for updates. |
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*/ |
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}; |
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/* this must be embedded in a deferred_request that is being |
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* delayed awaiting cache-fill |
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*/ |
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struct cache_deferred_req { |
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struct hlist_node hash; /* on hash chain */ |
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struct list_head recent; /* on fifo */ |
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struct cache_head *item; /* cache item we wait on */ |
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void *owner; /* we might need to discard all defered requests |
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* owned by someone */ |
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void (*revisit)(struct cache_deferred_req *req, |
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int too_many); |
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}; |
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/* |
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* timestamps kept in the cache are expressed in seconds |
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* since boot. This is the best for measuring differences in |
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* real time. |
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* This reimplemnts ktime_get_boottime_seconds() in a slightly |
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* faster but less accurate way. When we end up converting |
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* back to wallclock (CLOCK_REALTIME), that error often |
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* cancels out during the reverse operation. |
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*/ |
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static inline time64_t seconds_since_boot(void) |
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{ |
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struct timespec64 boot; |
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getboottime64(&boot); |
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return ktime_get_real_seconds() - boot.tv_sec; |
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} |
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static inline time64_t convert_to_wallclock(time64_t sinceboot) |
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{ |
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struct timespec64 boot; |
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getboottime64(&boot); |
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return boot.tv_sec + sinceboot; |
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} |
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extern const struct file_operations cache_file_operations_pipefs; |
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extern const struct file_operations content_file_operations_pipefs; |
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extern const struct file_operations cache_flush_operations_pipefs; |
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extern struct cache_head * |
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sunrpc_cache_lookup_rcu(struct cache_detail *detail, |
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struct cache_head *key, int hash); |
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extern struct cache_head * |
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sunrpc_cache_update(struct cache_detail *detail, |
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struct cache_head *new, struct cache_head *old, int hash); |
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extern int |
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sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h); |
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extern int |
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sunrpc_cache_pipe_upcall_timeout(struct cache_detail *detail, |
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struct cache_head *h); |
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extern void cache_clean_deferred(void *owner); |
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static inline struct cache_head *cache_get(struct cache_head *h) |
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{ |
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kref_get(&h->ref); |
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return h; |
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} |
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static inline struct cache_head *cache_get_rcu(struct cache_head *h) |
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{ |
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if (kref_get_unless_zero(&h->ref)) |
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return h; |
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return NULL; |
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} |
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static inline void cache_put(struct cache_head *h, struct cache_detail *cd) |
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{ |
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if (kref_read(&h->ref) <= 2 && |
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h->expiry_time < cd->nextcheck) |
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cd->nextcheck = h->expiry_time; |
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kref_put(&h->ref, cd->cache_put); |
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} |
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static inline bool cache_is_expired(struct cache_detail *detail, struct cache_head *h) |
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{ |
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if (h->expiry_time < seconds_since_boot()) |
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return true; |
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if (!test_bit(CACHE_VALID, &h->flags)) |
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return false; |
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return detail->flush_time >= h->last_refresh; |
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} |
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extern int cache_check(struct cache_detail *detail, |
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struct cache_head *h, struct cache_req *rqstp); |
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extern void cache_flush(void); |
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extern void cache_purge(struct cache_detail *detail); |
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#define NEVER (0x7FFFFFFF) |
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extern void __init cache_initialize(void); |
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extern int cache_register_net(struct cache_detail *cd, struct net *net); |
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extern void cache_unregister_net(struct cache_detail *cd, struct net *net); |
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extern struct cache_detail *cache_create_net(const struct cache_detail *tmpl, struct net *net); |
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extern void cache_destroy_net(struct cache_detail *cd, struct net *net); |
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extern void sunrpc_init_cache_detail(struct cache_detail *cd); |
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extern void sunrpc_destroy_cache_detail(struct cache_detail *cd); |
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extern int sunrpc_cache_register_pipefs(struct dentry *parent, const char *, |
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umode_t, struct cache_detail *); |
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extern void sunrpc_cache_unregister_pipefs(struct cache_detail *); |
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extern void sunrpc_cache_unhash(struct cache_detail *, struct cache_head *); |
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/* Must store cache_detail in seq_file->private if using next three functions */ |
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extern void *cache_seq_start_rcu(struct seq_file *file, loff_t *pos); |
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extern void *cache_seq_next_rcu(struct seq_file *file, void *p, loff_t *pos); |
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extern void cache_seq_stop_rcu(struct seq_file *file, void *p); |
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extern void qword_add(char **bpp, int *lp, char *str); |
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extern void qword_addhex(char **bpp, int *lp, char *buf, int blen); |
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extern int qword_get(char **bpp, char *dest, int bufsize); |
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static inline int get_int(char **bpp, int *anint) |
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{ |
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char buf[50]; |
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char *ep; |
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int rv; |
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int len = qword_get(bpp, buf, sizeof(buf)); |
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if (len < 0) |
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return -EINVAL; |
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if (len == 0) |
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return -ENOENT; |
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rv = simple_strtol(buf, &ep, 0); |
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if (*ep) |
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return -EINVAL; |
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*anint = rv; |
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return 0; |
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} |
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static inline int get_uint(char **bpp, unsigned int *anint) |
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{ |
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char buf[50]; |
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int len = qword_get(bpp, buf, sizeof(buf)); |
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if (len < 0) |
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return -EINVAL; |
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if (len == 0) |
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return -ENOENT; |
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if (kstrtouint(buf, 0, anint)) |
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return -EINVAL; |
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return 0; |
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} |
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static inline int get_time(char **bpp, time64_t *time) |
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{ |
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char buf[50]; |
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long long ll; |
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int len = qword_get(bpp, buf, sizeof(buf)); |
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if (len < 0) |
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return -EINVAL; |
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if (len == 0) |
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return -ENOENT; |
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if (kstrtoll(buf, 0, &ll)) |
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return -EINVAL; |
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*time = ll; |
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return 0; |
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} |
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static inline time64_t get_expiry(char **bpp) |
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{ |
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time64_t rv; |
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struct timespec64 boot; |
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if (get_time(bpp, &rv)) |
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return 0; |
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if (rv < 0) |
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return 0; |
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getboottime64(&boot); |
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return rv - boot.tv_sec; |
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} |
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#endif /* _LINUX_SUNRPC_CACHE_H_ */
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