diff options
| -rw-r--r-- | include/linux/sunrpc/cache.h | 12 | ||||
| -rw-r--r-- | net/sunrpc/cache.c | 98 |
2 files changed, 110 insertions, 0 deletions
diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h index 405ac14e509..3e17a5ff1de 100644 --- a/include/linux/sunrpc/cache.h +++ b/include/linux/sunrpc/cache.h @@ -81,6 +81,11 @@ struct cache_detail { 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 */ @@ -237,6 +242,13 @@ RTN *FNAME ARGS \ & FUNC##_cache, FUNC##_hash(item), FUNC##_match(item, tmp), \ STRUCT##_init(new, item), STRUCT##_update(tmp, 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); + #define cache_for_each(pos, detail, index, member) \ for (({read_lock(&(detail)->hash_lock); index = (detail)->hash_size;}) ; \ diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c index 0acccfeeb28..4449dc52edf 100644 --- a/net/sunrpc/cache.c +++ b/net/sunrpc/cache.c @@ -47,6 +47,104 @@ void cache_init(struct cache_head *h) h->last_refresh = now; } +struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail, + struct cache_head *key, int hash) +{ + struct cache_head **head, **hp; + struct cache_head *new = NULL; + + head = &detail->hash_table[hash]; + + read_lock(&detail->hash_lock); + + for (hp=head; *hp != NULL ; hp = &(*hp)->next) { + struct cache_head *tmp = *hp; + if (detail->match(tmp, key)) { + cache_get(tmp); + read_unlock(&detail->hash_lock); + return tmp; + } + } + read_unlock(&detail->hash_lock); + /* Didn't find anything, insert an empty entry */ + + new = detail->alloc(); + if (!new) + return NULL; + cache_init(new); + + write_lock(&detail->hash_lock); + + /* check if entry appeared while we slept */ + for (hp=head; *hp != NULL ; hp = &(*hp)->next) { + struct cache_head *tmp = *hp; + if (detail->match(tmp, key)) { + cache_get(tmp); + write_unlock(&detail->hash_lock); + detail->cache_put(new, detail); + return tmp; + } + } + detail->init(new, key); + new->next = *head; + *head = new; + detail->entries++; + cache_get(new); + write_unlock(&detail->hash_lock); + + return new; +} +EXPORT_SYMBOL(sunrpc_cache_lookup); + +struct cache_head *sunrpc_cache_update(struct cache_detail *detail, + struct cache_head *new, struct cache_head *old, int hash) +{ + /* The 'old' entry is to be replaced by 'new'. + * If 'old' is not VALID, we update it directly, + * otherwise we need to replace it + */ + struct cache_head **head; + struct cache_head *tmp; + + if (!test_bit(CACHE_VALID, &old->flags)) { + write_lock(&detail->hash_lock); + if (!test_bit(CACHE_VALID, &old->flags)) { + if (test_bit(CACHE_NEGATIVE, &new->flags)) + set_bit(CACHE_NEGATIVE, &old->flags); + else + detail->update(old, new); + /* FIXME cache_fresh should come first */ + write_unlock(&detail->hash_lock); + cache_fresh(detail, old, new->expiry_time); + return old; + } + write_unlock(&detail->hash_lock); + } + /* We need to insert a new entry */ + tmp = detail->alloc(); + if (!tmp) { + detail->cache_put(old, detail); + return NULL; + } + cache_init(tmp); + detail->init(tmp, old); + head = &detail->hash_table[hash]; + + write_lock(&detail->hash_lock); + if (test_bit(CACHE_NEGATIVE, &new->flags)) + set_bit(CACHE_NEGATIVE, &tmp->flags); + else + detail->update(tmp, new); + tmp->next = *head; + *head = tmp; + cache_get(tmp); + write_unlock(&detail->hash_lock); + cache_fresh(detail, tmp, new->expiry_time); + cache_fresh(detail, old, 0); + detail->cache_put(old, detail); + return tmp; +} +EXPORT_SYMBOL(sunrpc_cache_update); static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h); /* |