SUNRPC: Convert the credcache lookup code to use RCU
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/net/sunrpc/auth.c b/net/sunrpc/auth.c
index 00f9649..ad7bde2 100644
--- a/net/sunrpc/auth.c
+++ b/net/sunrpc/auth.c
@@ -112,6 +112,14 @@
static DEFINE_SPINLOCK(rpc_credcache_lock);
+static void
+rpcauth_unhash_cred_locked(struct rpc_cred *cred)
+{
+ hlist_del_rcu(&cred->cr_hash);
+ smp_mb__before_clear_bit();
+ clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
+}
+
/*
* Initialize RPC credential cache
*/
@@ -166,8 +174,7 @@
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);
+ rpcauth_unhash_cred_locked(cred);
}
}
spin_unlock(&rpc_credcache_lock);
@@ -207,8 +214,7 @@
continue;
get_rpccred(cred);
list_add_tail(&cred->cr_lru, free);
- smp_wmb();
- hlist_del_init(&cred->cr_hash);
+ rpcauth_unhash_cred_locked(cred);
}
}
@@ -218,10 +224,12 @@
static void
rpcauth_gc_credcache(struct rpc_cred_cache *cache, struct list_head *free)
{
- if (time_before(jiffies, cache->nextgc))
+ if (list_empty(&cred_unused) || time_before(jiffies, cache->nextgc))
return;
+ spin_lock(&rpc_credcache_lock);
cache->nextgc = jiffies + cache->expire;
rpcauth_prune_expired(free);
+ spin_unlock(&rpc_credcache_lock);
}
/*
@@ -234,42 +242,57 @@
LIST_HEAD(free);
struct rpc_cred_cache *cache = auth->au_credcache;
struct hlist_node *pos;
- struct rpc_cred *new = NULL,
- *cred = NULL,
- *entry;
+ struct rpc_cred *cred = NULL,
+ *entry, *new;
int nr = 0;
if (!(flags & RPCAUTH_LOOKUP_ROOTCREDS))
nr = acred->uid & RPC_CREDCACHE_MASK;
-retry:
+
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(entry, pos, &cache->hashtable[nr], cr_hash) {
+ if (!entry->cr_ops->crmatch(acred, entry, flags))
+ continue;
+ spin_lock(&rpc_credcache_lock);
+ if (test_bit(RPCAUTH_CRED_HASHED, &entry->cr_flags) == 0) {
+ spin_unlock(&rpc_credcache_lock);
+ continue;
+ }
+ cred = get_rpccred(entry);
+ spin_unlock(&rpc_credcache_lock);
+ break;
+ }
+ rcu_read_unlock();
+
+ if (cred != NULL) {
+ rpcauth_gc_credcache(cache, &free);
+ goto found;
+ }
+
+ new = auth->au_ops->crcreate(auth, acred, flags);
+ if (IS_ERR(new)) {
+ cred = new;
+ goto out;
+ }
+
spin_lock(&rpc_credcache_lock);
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)
- list_add_tail(&new->cr_lru, &free);
- else
- cred = new;
- }
- if (cred) {
- hlist_add_head(&cred->cr_hash, &cache->hashtable[nr]);
- }
- rpcauth_gc_credcache(cache, &free);
- spin_unlock(&rpc_credcache_lock);
-
- rpcauth_destroy_credlist(&free);
-
- if (!cred) {
- new = auth->au_ops->crcreate(auth, acred, flags);
- if (!IS_ERR(new))
- goto retry;
+ if (cred == NULL) {
cred = new;
- } else if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags)
+ set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
+ hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]);
+ } else
+ list_add_tail(&new->cr_lru, &free);
+ rpcauth_prune_expired(&free);
+ cache->nextgc = jiffies + cache->expire;
+ spin_unlock(&rpc_credcache_lock);
+found:
+ if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags)
&& cred->cr_ops->cr_init != NULL
&& !(flags & RPCAUTH_LOOKUP_NEW)) {
int res = cred->cr_ops->cr_init(auth, cred);
@@ -278,8 +301,9 @@
cred = ERR_PTR(res);
}
}
-
- return (struct rpc_cred *) cred;
+ rpcauth_destroy_credlist(&free);
+out:
+ return cred;
}
struct rpc_cred *
@@ -357,21 +381,20 @@
put_rpccred(struct rpc_cred *cred)
{
/* Fast path for unhashed credentials */
- if (!hlist_unhashed(&cred->cr_hash))
+ if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0)
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)) {
+ rpcauth_unhash_cred_locked(cred);
+ else if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) {
cred->cr_expire = jiffies;
list_add_tail(&cred->cr_lru, &cred_unused);
spin_unlock(&rpc_credcache_lock);
diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index 55c47ae..068fa6d 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -694,15 +694,25 @@
}
static void
-gss_destroy_cred(struct rpc_cred *rc)
+gss_free_cred(struct gss_cred *gss_cred)
{
- struct gss_cred *cred = container_of(rc, struct gss_cred, gc_base);
+ dprintk("RPC: gss_free_cred %p\n", gss_cred);
+ if (gss_cred->gc_ctx)
+ gss_put_ctx(gss_cred->gc_ctx);
+ kfree(gss_cred);
+}
- dprintk("RPC: gss_destroy_cred \n");
+static void
+gss_free_cred_callback(struct rcu_head *head)
+{
+ struct gss_cred *gss_cred = container_of(head, struct gss_cred, gc_base.cr_rcu);
+ gss_free_cred(gss_cred);
+}
- if (cred->gc_ctx)
- gss_put_ctx(cred->gc_ctx);
- kfree(cred);
+static void
+gss_destroy_cred(struct rpc_cred *cred)
+{
+ call_rcu(&cred->cr_rcu, gss_free_cred_callback);
}
/*
diff --git a/net/sunrpc/auth_unix.c b/net/sunrpc/auth_unix.c
index 29d50ff..f7ff6ad 100644
--- a/net/sunrpc/auth_unix.c
+++ b/net/sunrpc/auth_unix.c
@@ -93,11 +93,23 @@
}
static void
-unx_destroy_cred(struct rpc_cred *rcred)
+unx_free_cred(struct unx_cred *unx_cred)
{
- struct unx_cred *cred = container_of(rcred, struct unx_cred, uc_base);
+ dprintk("RPC: unx_free_cred %p\n", unx_cred);
+ kfree(unx_cred);
+}
- kfree(cred);
+static void
+unx_free_cred_callback(struct rcu_head *head)
+{
+ struct unx_cred *unx_cred = container_of(head, struct unx_cred, uc_base.cr_rcu);
+ unx_free_cred(unx_cred);
+}
+
+static void
+unx_destroy_cred(struct rpc_cred *cred)
+{
+ call_rcu(&cred->cr_rcu, unx_free_cred_callback);
}
/*