SUNRPC: cleanup rpc credential cache garbage collection
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/include/linux/sunrpc/auth.h b/include/linux/sunrpc/auth.h
index 8586503..4e78f0c 100644
--- a/include/linux/sunrpc/auth.h
+++ b/include/linux/sunrpc/auth.h
@@ -34,6 +34,7 @@
struct rpc_credops;
struct rpc_cred {
struct hlist_node cr_hash; /* hash chain */
+ struct list_head cr_lru; /* lru garbage collection */
struct rpc_auth * cr_auth;
const struct rpc_credops *cr_ops;
#ifdef RPC_DEBUG
diff --git a/net/sunrpc/auth.c b/net/sunrpc/auth.c
index 4d7c78b..00f9649 100644
--- a/net/sunrpc/auth.c
+++ b/net/sunrpc/auth.c
@@ -25,6 +25,8 @@
NULL, /* others can be loadable modules */
};
+static LIST_HEAD(cred_unused);
+
static u32
pseudoflavor_to_flavor(u32 flavor) {
if (flavor >= RPC_AUTH_MAXFLAVOR)
@@ -134,13 +136,13 @@
* Destroy a list of credentials
*/
static inline
-void rpcauth_destroy_credlist(struct hlist_head *head)
+void rpcauth_destroy_credlist(struct list_head *head)
{
struct rpc_cred *cred;
- while (!hlist_empty(head)) {
- cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
- hlist_del_init(&cred->cr_hash);
+ while (!list_empty(head)) {
+ cred = list_entry(head->next, struct rpc_cred, cr_lru);
+ list_del_init(&cred->cr_lru);
put_rpccred(cred);
}
}
@@ -152,17 +154,20 @@
void
rpcauth_clear_credcache(struct rpc_cred_cache *cache)
{
- HLIST_HEAD(free);
- struct hlist_node *pos, *next;
+ LIST_HEAD(free);
+ struct hlist_head *head;
struct rpc_cred *cred;
int i;
spin_lock(&rpc_credcache_lock);
for (i = 0; i < RPC_CREDCACHE_NR; i++) {
- hlist_for_each_safe(pos, next, &cache->hashtable[i]) {
- cred = hlist_entry(pos, struct rpc_cred, cr_hash);
- __hlist_del(&cred->cr_hash);
- hlist_add_head(&cred->cr_hash, &free);
+ head = &cache->hashtable[i];
+ while (!hlist_empty(head)) {
+ cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
+ get_rpccred(cred);
+ list_move_tail(&cred->cr_lru, &free);
+ smp_wmb();
+ hlist_del_init(&cred->cr_hash);
}
}
spin_unlock(&rpc_credcache_lock);
@@ -184,38 +189,39 @@
}
}
-static void
-rpcauth_prune_expired(struct rpc_auth *auth, struct rpc_cred *cred, struct hlist_head *free)
-{
- if (atomic_read(&cred->cr_count) != 1)
- return;
- if (time_after(jiffies, cred->cr_expire + auth->au_credcache->expire))
- clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
- if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) == 0) {
- __hlist_del(&cred->cr_hash);
- hlist_add_head(&cred->cr_hash, free);
- }
-}
-
/*
* Remove stale credentials. Avoid sleeping inside the loop.
*/
static void
-rpcauth_gc_credcache(struct rpc_auth *auth, struct hlist_head *free)
+rpcauth_prune_expired(struct list_head *free)
{
- struct rpc_cred_cache *cache = auth->au_credcache;
- struct hlist_node *pos, *next;
- struct rpc_cred *cred;
- int i;
+ struct rpc_cred *cred;
- dprintk("RPC: gc'ing RPC credentials for auth %p\n", auth);
- for (i = 0; i < RPC_CREDCACHE_NR; i++) {
- hlist_for_each_safe(pos, next, &cache->hashtable[i]) {
- cred = hlist_entry(pos, struct rpc_cred, cr_hash);
- rpcauth_prune_expired(auth, cred, free);
- }
+ while (!list_empty(&cred_unused)) {
+ cred = list_entry(cred_unused.next, struct rpc_cred, cr_lru);
+ if (time_after(jiffies, cred->cr_expire +
+ cred->cr_auth->au_credcache->expire))
+ break;
+ list_del_init(&cred->cr_lru);
+ if (atomic_read(&cred->cr_count) != 0)
+ continue;
+ get_rpccred(cred);
+ list_add_tail(&cred->cr_lru, free);
+ smp_wmb();
+ hlist_del_init(&cred->cr_hash);
}
+}
+
+/*
+ * Run garbage collector.
+ */
+static void
+rpcauth_gc_credcache(struct rpc_cred_cache *cache, struct list_head *free)
+{
+ if (time_before(jiffies, cache->nextgc))
+ return;
cache->nextgc = jiffies + cache->expire;
+ rpcauth_prune_expired(free);
}
/*
@@ -225,39 +231,35 @@
rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
int flags)
{
+ LIST_HEAD(free);
struct rpc_cred_cache *cache = auth->au_credcache;
- HLIST_HEAD(free);
- struct hlist_node *pos, *next;
+ struct hlist_node *pos;
struct rpc_cred *new = NULL,
- *cred = NULL;
+ *cred = NULL,
+ *entry;
int nr = 0;
if (!(flags & RPCAUTH_LOOKUP_ROOTCREDS))
nr = acred->uid & RPC_CREDCACHE_MASK;
retry:
spin_lock(&rpc_credcache_lock);
- if (time_before(cache->nextgc, jiffies))
- rpcauth_gc_credcache(auth, &free);
- hlist_for_each_safe(pos, next, &cache->hashtable[nr]) {
- struct rpc_cred *entry;
- entry = hlist_entry(pos, struct rpc_cred, cr_hash);
- if (entry->cr_ops->crmatch(acred, entry, flags)) {
- hlist_del(&entry->cr_hash);
- cred = entry;
- break;
- }
- rpcauth_prune_expired(auth, entry, &free);
+ hlist_for_each_entry(entry, pos, &cache->hashtable[nr], cr_hash) {
+ if (!entry->cr_ops->crmatch(acred, entry, flags))
+ continue;
+ cred = get_rpccred(entry);
+ hlist_del(&entry->cr_hash);
+ break;
}
if (new) {
if (cred)
- hlist_add_head(&new->cr_hash, &free);
+ list_add_tail(&new->cr_lru, &free);
else
cred = new;
}
if (cred) {
hlist_add_head(&cred->cr_hash, &cache->hashtable[nr]);
- get_rpccred(cred);
}
+ rpcauth_gc_credcache(cache, &free);
spin_unlock(&rpc_credcache_lock);
rpcauth_destroy_credlist(&free);
@@ -303,6 +305,7 @@
struct rpc_auth *auth, const struct rpc_credops *ops)
{
INIT_HLIST_NODE(&cred->cr_hash);
+ INIT_LIST_HEAD(&cred->cr_lru);
atomic_set(&cred->cr_count, 1);
cred->cr_auth = auth;
cred->cr_ops = ops;
@@ -353,9 +356,29 @@
void
put_rpccred(struct rpc_cred *cred)
{
- cred->cr_expire = jiffies;
+ /* Fast path for unhashed credentials */
+ if (!hlist_unhashed(&cred->cr_hash))
+ goto need_lock;
+
if (!atomic_dec_and_test(&cred->cr_count))
return;
+ goto out_destroy;
+
+need_lock:
+ if (!atomic_dec_and_lock(&cred->cr_count, &rpc_credcache_lock))
+ return;
+ if (!list_empty(&cred->cr_lru))
+ list_del_init(&cred->cr_lru);
+ if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) == 0)
+ hlist_del(&cred->cr_hash);
+ else if (!hlist_unhashed(&cred->cr_hash)) {
+ cred->cr_expire = jiffies;
+ list_add_tail(&cred->cr_lru, &cred_unused);
+ spin_unlock(&rpc_credcache_lock);
+ return;
+ }
+ spin_unlock(&rpc_credcache_lock);
+out_destroy:
cred->cr_ops->crdestroy(cred);
}
diff --git a/net/sunrpc/auth_null.c b/net/sunrpc/auth_null.c
index 6c905fb..537d0e8 100644
--- a/net/sunrpc/auth_null.c
+++ b/net/sunrpc/auth_null.c
@@ -133,6 +133,7 @@
static
struct rpc_cred null_cred = {
+ .cr_lru = LIST_HEAD_INIT(null_cred.cr_lru),
.cr_auth = &null_auth,
.cr_ops = &null_credops,
.cr_count = ATOMIC_INIT(1),
