/*
* This is the generic cache management routine for all
* the authentication caches.
* It checks the currency of a cache item and will (later)
* initiate an upcall to fill it if needed.
*
*
* Returns 0 if the cache_head can be used, or cache_puts it and returns
* -EAGAIN if upcall is pending,
* -ENOENT if cache entry was negative
*/
int cache_check(struct cache_detail *detail,
struct cache_head *h, struct cache_req *rqstp)
{
int rv;
long refresh_age, age;
/* First decide return status as best we can */
if (!test_bit(CACHE_VALID, &h->flags) ||
h->expiry_time < get_seconds())
rv = -EAGAIN;
else if (detail->flush_time > h->last_refresh)
rv = -EAGAIN;
else {
/* entry is valid */
if (test_bit(CACHE_NEGATIVE, &h->flags))
rv = -ENOENT;
else rv = 0;
}
/* now see if we want to start an upcall */
refresh_age = (h->expiry_time - h->last_refresh);
age = get_seconds() - h->last_refresh;
if (rqstp == NULL) {
if (rv == -EAGAIN)
rv = -ENOENT;
} else if (rv == -EAGAIN || age > refresh_age/2) {
dprintk("Want update, refage=%ld, age=%ld\n", refresh_age, age);
if (!test_and_set_bit(CACHE_PENDING, &h->flags)) {
switch (cache_make_upcall(detail, h)) {
case -EINVAL:
clear_bit(CACHE_PENDING, &h->flags);
if (rv == -EAGAIN) {
set_bit(CACHE_NEGATIVE, &h->flags);
cache_fresh(detail, h, get_seconds()+CACHE_NEW_EXPIRY);
rv = -ENOENT;
}
break;
case -EAGAIN:
clear_bit(CACHE_PENDING, &h->flags);
cache_revisit_request(h);
break;
}
}
}
if (rv == -EAGAIN)
cache_defer_req(rqstp, h);
if (rv && h)
detail->cache_put(h, detail);
return rv;
}
struct auth_domain *
auth_domain_lookup(struct auth_domain *item, int set)
{
struct auth_domain *tmp = NULL;
struct cache_head **hp, **head;
head = &auth_domain_cache.hash_table[auth_domain_hash(item)];
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;
cache_get(&tmp->h);
if (!set)
goto out_noset;
*hp = tmp->h.next;
tmp->h.next = NULL;
clear_bit(CACHE_HASHED, &tmp->h.flags);
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:
set_bit(CACHE_HASHED, &item->h.flags);
item->h.next = *head;
*head = &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;
}