--- /dev/null
+/*
+ * 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 *);
+
+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_ */
Code Review / kvmfornfv.git / blobdiff