time_t last_refresh; /* If CACHE_PENDING, this is when upcall
* was sent, else this is when update was received
*/
- atomic_t refcnt;
+ struct kref ref;
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 cache_head *,
- struct cache_detail*);
+ void (*cache_put)(struct kref *);
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.
- * 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; \
-}
+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);
-#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)
{
- atomic_inc(&h->refcnt);
+ kref_get(&h->ref);
return h;
}
-static inline int cache_put(struct cache_head *h, struct cache_detail *cd)
+static inline void cache_put(struct cache_head *h, struct cache_detail *cd)
{
- if (atomic_read(&h->refcnt) <= 2 &&
+ if (atomic_read(&h->ref.refcount) <= 2 &&
h->expiry_time < cd->nextcheck)
cd->nextcheck = h->expiry_time;
- return atomic_dec_and_test(&h->refcnt);
+ kref_put(&h->ref, cd->cache_put);
+}
+
+static inline int cache_valid(struct cache_head *h)
+{
+ /* If an item has been unhashed pending removal when
+ * the refcount drops to 0, the expiry_time will be
+ * set to 0. We don't want to consider such items
+ * valid in this context even though CACHE_VALID is
+ * set.
+ */
+ return (h->expiry_time != 0 && test_bit(CACHE_VALID, &h->flags));
}
-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