[PATCH] knfsd: Change the store of auth_domains to not be a 'cache'
The 'auth_domain's are simply handles on internal data structures. They do
not cache information from user-space, and forcing them into the mold of a
'cache' misrepresents their true nature and causes confusion.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/net/sunrpc/svcauth.c b/net/sunrpc/svcauth.c
index dda4f0c..5b28c61 100644
--- a/net/sunrpc/svcauth.c
+++ b/net/sunrpc/svcauth.c
@@ -106,112 +106,56 @@
EXPORT_SYMBOL(svc_auth_unregister);
/**************************************************
- * cache for domain name to auth_domain
- * Entries are only added by flavours which will normally
- * have a structure that 'inherits' from auth_domain.
- * e.g. when an IP -> domainname is given to auth_unix,
- * and the domain name doesn't exist, it will create a
- * auth_unix_domain and add it to this hash table.
- * If it finds the name does exist, but isn't AUTH_UNIX,
- * it will complain.
+ * 'auth_domains' are stored in a hash table indexed by name.
+ * When the last reference to an 'auth_domain' is dropped,
+ * the object is unhashed and freed.
+ * If auth_domain_lookup fails to find an entry, it will return
+ * it's second argument 'new'. If this is non-null, it will
+ * have been atomically linked into the table.
*/
-/*
- * Auth auth_domain cache is somewhat different to other caches,
- * largely because the entries are possibly of different types:
- * each auth flavour has it's own type.
- * One consequence of this that DefineCacheLookup cannot
- * allocate a new structure as it cannot know the size.
- * Notice that the "INIT" code fragment is quite different
- * from other caches. When auth_domain_lookup might be
- * creating a new domain, the new domain is passed in
- * complete and it is used as-is rather than being copied into
- * another structure.
- */
#define DN_HASHBITS 6
#define DN_HASHMAX (1<<DN_HASHBITS)
#define DN_HASHMASK (DN_HASHMAX-1)
-static struct cache_head *auth_domain_table[DN_HASHMAX];
-
-static void auth_domain_drop(struct cache_head *item, struct cache_detail *cd)
-{
- struct auth_domain *dom = container_of(item, struct auth_domain, h);
- if (cache_put(item,cd))
- authtab[dom->flavour]->domain_release(dom);
-}
-
-
-struct cache_detail auth_domain_cache = {
- .owner = THIS_MODULE,
- .hash_size = DN_HASHMAX,
- .hash_table = auth_domain_table,
- .name = "auth.domain",
- .cache_put = auth_domain_drop,
-};
+static struct hlist_head auth_domain_table[DN_HASHMAX];
+static spinlock_t auth_domain_lock = SPIN_LOCK_UNLOCKED;
void auth_domain_put(struct auth_domain *dom)
{
- auth_domain_drop(&dom->h, &auth_domain_cache);
-}
-
-static inline int auth_domain_hash(struct auth_domain *item)
-{
- return hash_str(item->name, DN_HASHBITS);
-}
-static inline int auth_domain_match(struct auth_domain *tmp, struct auth_domain *item)
-{
- return strcmp(tmp->name, item->name) == 0;
+ if (atomic_dec_and_lock(&dom->ref.refcount, &auth_domain_lock)) {
+ hlist_del(&dom->hash);
+ dom->flavour->domain_release(dom);
+ }
}
struct auth_domain *
-auth_domain_lookup(struct auth_domain *item, int set)
+auth_domain_lookup(char *name, struct auth_domain *new)
{
- struct auth_domain *tmp = NULL;
- struct cache_head **hp, **head;
- head = &auth_domain_cache.hash_table[auth_domain_hash(item)];
+ struct auth_domain *hp;
+ struct hlist_head *head;
+ struct hlist_node *np;
- if (set)
- write_lock(&auth_domain_cache.hash_lock);
- else
- read_lock(&auth_domain_cache.hash_lock);
- for (hp=head; *hp != NULL; hp = &tmp->h.next) {
- tmp = container_of(*hp, struct auth_domain, h);
- if (!auth_domain_match(tmp, item))
- continue;
- if (!set) {
- cache_get(&tmp->h);
- goto out_noset;
+ head = &auth_domain_table[hash_str(name, DN_HASHBITS)];
+
+ spin_lock(&auth_domain_lock);
+
+ hlist_for_each_entry(hp, np, head, hash) {
+ if (strcmp(hp->name, name)==0) {
+ kref_get(&hp->ref);
+ spin_unlock(&auth_domain_lock);
+ return hp;
}
- *hp = tmp->h.next;
- tmp->h.next = NULL;
- auth_domain_drop(&tmp->h, &auth_domain_cache);
- goto out_set;
}
- /* Didn't find anything */
- if (!set)
- goto out_nada;
- auth_domain_cache.entries++;
-out_set:
- item->h.next = *head;
- *head = &item->h;
- cache_get(&item->h);
- write_unlock(&auth_domain_cache.hash_lock);
- cache_fresh(&auth_domain_cache, &item->h, item->h.expiry_time);
- cache_get(&item->h);
- return item;
-out_nada:
- tmp = NULL;
-out_noset:
- read_unlock(&auth_domain_cache.hash_lock);
- return tmp;
+ if (new) {
+ hlist_add_head(&new->hash, head);
+ kref_get(&new->ref);
+ }
+ spin_unlock(&auth_domain_lock);
+ return new;
}
struct auth_domain *auth_domain_find(char *name)
{
- struct auth_domain *rv, ad;
-
- ad.name = name;
- rv = auth_domain_lookup(&ad, 0);
- return rv;
+ return auth_domain_lookup(name, NULL);
}