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-rw-r--r--include/linux/sunrpc/cache.h312
1 files changed, 312 insertions, 0 deletions
diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h
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+++ b/include/linux/sunrpc/cache.h
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+/*
+ * 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/slab.h>
+#include <asm/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 existance
+ * in the hash table.
+ * We only expire entries when refcount is zero.
+ * Existance 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
+ */
+ atomic_t refcnt;
+ 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_NEW_EXPIRY 120 /* keep new things pending confirmation for 120 seconds */
+
+struct cache_detail {
+ 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 cache_head *,
+ struct cache_detail*);
+
+ void (*cache_request)(struct cache_detail *cd,
+ struct cache_head *h,
+ 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);
+
+ /* 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;
+ struct proc_dir_entry *proc_ent;
+ struct proc_dir_entry *flush_ent, *channel_ent, *content_ent;
+
+ 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 */
+ void (*warn_no_listener)(struct cache_detail *cd);
+};
+
+
+/* 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);
+};
+/* this must be embedded in a deferred_request that is being
+ * delayed awaiting cache-fill
+ */
+struct cache_deferred_req {
+ struct list_head hash; /* on hash chain */
+ struct list_head recent; /* on fifo */
+ struct cache_head *item; /* cache item we wait on */
+ time_t recv_time;
+ void *owner; /* we might need to discard all defered requests
+ * owned by someone */
+ void (*revisit)(struct cache_deferred_req *req,
+ int too_many);
+};
+
+/*
+ * just like a template in C++, this macro does cache lookup
+ * for us.
+ * The function is passed some sort of HANDLE from which a cache_detail
+ * structure can be determined (via SETUP, DETAIL), a template
+ * cache entry (type RTN*), and a "set" flag. Using the HASHFN and the
+ * TEST, the function will try to find a matching cache entry in the cache.
+ * If "set" == 0 :
+ * If an entry is found, it is returned
+ * If no entry is found, a new non-VALID entry is created.
+ * If "set" == 1 and INPLACE == 0 :
+ * If no entry is found a new one is inserted with data from "template"
+ * If a non-CACHE_VALID entry is found, it is updated from template using UPDATE
+ * If a CACHE_VALID entry is found, a new entry is swapped in with data
+ * from "template"
+ * If set == 1, and INPLACE == 1 :
+ * As above, except that if a CACHE_VALID entry is found, we UPDATE in place
+ * instead of swapping in a new entry.
+ *
+ * If the passed handle has the CACHE_NEGATIVE flag set, then UPDATE is not
+ * run but insteead CACHE_NEGATIVE is set in any new item.
+
+ * In any case, the new entry is returned with a reference count.
+ *
+ *
+ * RTN is a struct type for a cache entry
+ * MEMBER is the member of the cache which is cache_head, which must be first
+ * FNAME is the name for the function
+ * ARGS are arguments to function and must contain RTN *item, int set. May
+ * also contain something to be usedby SETUP or DETAIL to find cache_detail.
+ * SETUP locates the cache detail and makes it available as...
+ * DETAIL identifies the cache detail, possibly set up by SETUP
+ * HASHFN returns a hash value of the cache entry "item"
+ * TEST tests if "tmp" matches "item"
+ * INIT copies key information from "item" to "new"
+ * UPDATE copies content information from "item" to "tmp"
+ * INPLACE is true if updates can happen inplace rather than allocating a new structure
+ *
+ * WARNING: any substantial changes to this must be reflected in
+ * net/sunrpc/svcauth.c(auth_domain_lookup)
+ * which is a similar routine that is open-coded.
+ */
+#define DefineCacheLookup(RTN,MEMBER,FNAME,ARGS,SETUP,DETAIL,HASHFN,TEST,INIT,UPDATE,INPLACE) \
+RTN *FNAME ARGS \
+{ \
+ RTN *tmp, *new=NULL; \
+ struct cache_head **hp, **head; \
+ SETUP; \
+ head = &(DETAIL)->hash_table[HASHFN]; \
+ retry: \
+ if (set||new) write_lock(&(DETAIL)->hash_lock); \
+ else read_lock(&(DETAIL)->hash_lock); \
+ for(hp=head; *hp != NULL; hp = &tmp->MEMBER.next) { \
+ tmp = container_of(*hp, RTN, MEMBER); \
+ if (TEST) { /* found a match */ \
+ \
+ if (set && !INPLACE && test_bit(CACHE_VALID, &tmp->MEMBER.flags) && !new) \
+ break; \
+ \
+ if (new) \
+ {INIT;} \
+ if (set) { \
+ if (!INPLACE && test_bit(CACHE_VALID, &tmp->MEMBER.flags))\
+ { /* need to swap in new */ \
+ RTN *t2; \
+ \
+ new->MEMBER.next = tmp->MEMBER.next; \
+ *hp = &new->MEMBER; \
+ tmp->MEMBER.next = NULL; \
+ t2 = tmp; tmp = new; new = t2; \
+ } \
+ if (test_bit(CACHE_NEGATIVE, &item->MEMBER.flags)) \
+ set_bit(CACHE_NEGATIVE, &tmp->MEMBER.flags); \
+ else { \
+ UPDATE; \
+ clear_bit(CACHE_NEGATIVE, &tmp->MEMBER.flags); \
+ } \
+ } \
+ cache_get(&tmp->MEMBER); \
+ if (set||new) write_unlock(&(DETAIL)->hash_lock); \
+ else read_unlock(&(DETAIL)->hash_lock); \
+ if (set) \
+ cache_fresh(DETAIL, &tmp->MEMBER, item->MEMBER.expiry_time); \
+ if (set && !INPLACE && new) cache_fresh(DETAIL, &new->MEMBER, 0); \
+ if (new) (DETAIL)->cache_put(&new->MEMBER, DETAIL); \
+ return tmp; \
+ } \
+ } \
+ /* Didn't find anything */ \
+ if (new) { \
+ INIT; \
+ new->MEMBER.next = *head; \
+ *head = &new->MEMBER; \
+ (DETAIL)->entries ++; \
+ cache_get(&new->MEMBER); \
+ if (set) { \
+ tmp = new; \
+ if (test_bit(CACHE_NEGATIVE, &item->MEMBER.flags)) \
+ set_bit(CACHE_NEGATIVE, &tmp->MEMBER.flags); \
+ else {UPDATE;} \
+ } \
+ } \
+ if (set||new) write_unlock(&(DETAIL)->hash_lock); \
+ else read_unlock(&(DETAIL)->hash_lock); \
+ if (new && set) \
+ cache_fresh(DETAIL, &new->MEMBER, item->MEMBER.expiry_time); \
+ if (new) \
+ return new; \
+ new = kmalloc(sizeof(*new), GFP_KERNEL); \
+ if (new) { \
+ cache_init(&new->MEMBER); \
+ goto retry; \
+ } \
+ return NULL; \
+}
+
+#define DefineSimpleCacheLookup(STRUCT,INPLACE) \
+ DefineCacheLookup(struct STRUCT, h, STRUCT##_lookup, (struct STRUCT *item, int set), /*no setup */, \
+ & STRUCT##_cache, STRUCT##_hash(item), STRUCT##_match(item, tmp),\
+ STRUCT##_init(new, item), STRUCT##_update(tmp, item),INPLACE)
+
+#define cache_for_each(pos, detail, index, member) \
+ for (({read_lock(&(detail)->hash_lock); index = (detail)->hash_size;}) ; \
+ ({if (index==0)read_unlock(&(detail)->hash_lock); index--;}); \
+ ) \
+ for (pos = container_of((detail)->hash_table[index], typeof(*pos), member); \
+ &pos->member; \
+ pos = container_of(pos->member.next, typeof(*pos), member))
+
+
+
+extern void cache_clean_deferred(void *owner);
+
+static inline struct cache_head *cache_get(struct cache_head *h)
+{
+ atomic_inc(&h->refcnt);
+ return h;
+}
+
+
+static inline int cache_put(struct cache_head *h, struct cache_detail *cd)
+{
+ if (atomic_read(&h->refcnt) <= 2 &&
+ h->expiry_time < cd->nextcheck)
+ cd->nextcheck = h->expiry_time;
+ return atomic_dec_and_test(&h->refcnt);
+}
+
+extern void cache_init(struct cache_head *h);
+extern void cache_fresh(struct cache_detail *detail,
+ struct cache_head *head, time_t expiry);
+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 cache_register(struct cache_detail *cd);
+extern int cache_unregister(struct cache_detail *cd);
+
+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, 50);
+ 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 time_t get_expiry(char **bpp)
+{
+ int rv;
+ if (get_int(bpp, &rv))
+ return 0;
+ if (rv < 0)
+ return 0;
+ return rv;
+}
+
+#endif /* _LINUX_SUNRPC_CACHE_H_ */