time_t last_refresh; /* If CACHE_PENDING, this is when upcall
* was sent, else this is when update was received
*/
- struct kref ref;
+ atomic_t refcnt;
unsigned long flags;
};
#define CACHE_VALID 0 /* Entry contains valid data */
atomic_t inuse; /* active user-space update or lookup */
char *name;
- void (*cache_put)(struct kref *);
+ void (*cache_put)(struct cache_head *,
+ struct cache_detail*);
void (*cache_request)(struct cache_detail *cd,
struct cache_head *h,
struct cache_detail *cd,
struct cache_head *h);
- 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
*/
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.
-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);
+ * 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;}) ; \
static inline struct cache_head *cache_get(struct cache_head *h)
{
- kref_get(&h->ref);
+ atomic_inc(&h->refcnt);
return h;
}
-static inline void cache_put(struct cache_head *h, struct cache_detail *cd)
+static inline int cache_put(struct cache_head *h, struct cache_detail *cd)
{
- if (atomic_read(&h->ref.refcount) <= 2 &&
+ if (atomic_read(&h->refcnt) <= 2 &&
h->expiry_time < cd->nextcheck)
cd->nextcheck = h->expiry_time;
- kref_put(&h->ref, cd->cache_put);
+ 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);
git://git.onelab.eu / linux-2.6.git / blobdiff