SUNRPC: Give credential cache a local spinlock

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

4 files changed, 41 insertions, 14 deletions

diff --git a/include/linux/sunrpc/auth.h b/include/linux/sunrpc/auth.h
index 5974e8a493c4..e5a3b5141ed2 100644
--- a/include/linux/sunrpc/auth.h
+++ b/include/linux/sunrpc/auth.h
@@ -63,6 +63,7 @@ struct rpc_cred {
 #define RPC_CREDCACHE_MASK      (RPC_CREDCACHE_NR - 1)
 struct rpc_cred_cache {
         struct hlist_head       hashtable[RPC_CREDCACHE_NR];
+        spinlock_t              lock;
         unsigned long           nextgc;         /* next garbage collection */
         unsigned long           expire;         /* cache expiry interval */
 };
@@ -126,6 +127,8 @@ struct rpc_credops {
 extern const struct rpc_authops authunix_ops;
 extern const struct rpc_authops authnull_ops;
 
+void __init             rpc_init_authunix(void);
+
 int                     rpcauth_register(const struct rpc_authops *);
 int                     rpcauth_unregister(const struct rpc_authops *);
 struct rpc_auth *       rpcauth_create(rpc_authflavor_t, struct rpc_clnt *);
diff --git a/net/sunrpc/auth.c b/net/sunrpc/auth.c
index ad7bde2c437e..cf1198d10ee9 100644
--- a/net/sunrpc/auth.c
+++ b/net/sunrpc/auth.c
@@ -120,6 +120,18 @@ rpcauth_unhash_cred_locked(struct rpc_cred *cred)
         clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
 }
 
+static void
+rpcauth_unhash_cred(struct rpc_cred *cred)
+{
+        spinlock_t *cache_lock;
+
+        cache_lock = &cred->cr_auth->au_credcache->lock;
+        spin_lock(cache_lock);
+        if (atomic_read(&cred->cr_count) == 0)
+                rpcauth_unhash_cred_locked(cred);
+        spin_unlock(cache_lock);
+}
+
 /*
  * Initialize RPC credential cache
  */
@@ -134,6 +146,7 @@ rpcauth_init_credcache(struct rpc_auth *auth, unsigned long expire)
                 return -ENOMEM;
         for (i = 0; i < RPC_CREDCACHE_NR; i++)
                 INIT_HLIST_HEAD(&new->hashtable[i]);
+        spin_lock_init(&new->lock);
         new->expire = expire;
         new->nextgc = jiffies + (expire >> 1);
         auth->au_credcache = new;
@@ -168,6 +181,7 @@ rpcauth_clear_credcache(struct rpc_cred_cache *cache)
         int             i;
 
         spin_lock(&rpc_credcache_lock);
+        spin_lock(&cache->lock);
         for (i = 0; i < RPC_CREDCACHE_NR; i++) {
                 head = &cache->hashtable[i];
                 while (!hlist_empty(head)) {
@@ -177,6 +191,7 @@ rpcauth_clear_credcache(struct rpc_cred_cache *cache)
                         rpcauth_unhash_cred_locked(cred);
                 }
         }
+        spin_unlock(&cache->lock);
         spin_unlock(&rpc_credcache_lock);
         rpcauth_destroy_credlist(&free);
 }
@@ -202,6 +217,7 @@ rpcauth_destroy_credcache(struct rpc_auth *auth)
 static void
 rpcauth_prune_expired(struct list_head *free)
 {
+        spinlock_t *cache_lock;
         struct rpc_cred *cred;
 
         while (!list_empty(&cred_unused)) {
@@ -212,9 +228,14 @@ rpcauth_prune_expired(struct list_head *free)
                 list_del_init(&cred->cr_lru);
                 if (atomic_read(&cred->cr_count) != 0)
                         continue;
-                get_rpccred(cred);
-                list_add_tail(&cred->cr_lru, free);
-                rpcauth_unhash_cred_locked(cred);
+                cache_lock = &cred->cr_auth->au_credcache->lock;
+                spin_lock(cache_lock);
+                if (atomic_read(&cred->cr_count) == 0) {
+                        get_rpccred(cred);
+                        list_add_tail(&cred->cr_lru, free);
+                        rpcauth_unhash_cred_locked(cred);
+                }
+                spin_unlock(cache_lock);
         }
 }
 
@@ -253,21 +274,19 @@ rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
         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);
+                spin_lock(&cache->lock);
                 if (test_bit(RPCAUTH_CRED_HASHED, &entry->cr_flags) == 0) {
-                        spin_unlock(&rpc_credcache_lock);
+                        spin_unlock(&cache->lock);
                         continue;
                 }
                 cred = get_rpccred(entry);
-                spin_unlock(&rpc_credcache_lock);
+                spin_unlock(&cache->lock);
                 break;
         }
         rcu_read_unlock();
 
-        if (cred != NULL) {
-                rpcauth_gc_credcache(cache, &free);
+        if (cred != NULL)
                 goto found;
-        }
 
         new = auth->au_ops->crcreate(auth, acred, flags);
         if (IS_ERR(new)) {
@@ -275,7 +294,7 @@ rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
                 goto out;
         }
 
-        spin_lock(&rpc_credcache_lock);
+        spin_lock(&cache->lock);
         hlist_for_each_entry(entry, pos, &cache->hashtable[nr], cr_hash) {
                 if (!entry->cr_ops->crmatch(acred, entry, flags))
                         continue;
@@ -288,9 +307,7 @@ rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
                 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);
+        spin_unlock(&cache->lock);
 found:
         if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags)
                         && cred->cr_ops->cr_init != NULL
@@ -301,6 +318,7 @@ found:
                         cred = ERR_PTR(res);
                 }
         }
+        rpcauth_gc_credcache(cache, &free);
         rpcauth_destroy_credlist(&free);
 out:
         return cred;
@@ -393,7 +411,7 @@ need_lock:
         if (!list_empty(&cred->cr_lru))
                 list_del_init(&cred->cr_lru);
         if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) == 0)
-                rpcauth_unhash_cred_locked(cred);
+                rpcauth_unhash_cred(cred);
         else if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) {
                 cred->cr_expire = jiffies;
                 list_add_tail(&cred->cr_lru, &cred_unused);
diff --git a/net/sunrpc/auth_unix.c b/net/sunrpc/auth_unix.c
index f7ff6ad3259e..205878a3caa5 100644
--- a/net/sunrpc/auth_unix.c
+++ b/net/sunrpc/auth_unix.c
@@ -213,6 +213,11 @@ unx_validate(struct rpc_task *task, __be32 *p)
         return p;
 }
 
+void __init rpc_init_authunix(void)
+{
+        spin_lock_init(&unix_cred_cache.lock);
+}
+
 const struct rpc_authops authunix_ops = {
         .owner          = THIS_MODULE,
         .au_flavor      = RPC_AUTH_UNIX,
diff --git a/net/sunrpc/sunrpc_syms.c b/net/sunrpc/sunrpc_syms.c
index 3e19e7af6799..018065fca84b 100644
--- a/net/sunrpc/sunrpc_syms.c
+++ b/net/sunrpc/sunrpc_syms.c
@@ -152,6 +152,7 @@ init_sunrpc(void)
         cache_register(&ip_map_cache);
         cache_register(&unix_gid_cache);
         init_socket_xprt();
+        rpc_init_authunix();
 out:
         return err;
 }