diff options
| -rw-r--r-- | net/sunrpc/auth.c | 147 | ||||
| -rw-r--r-- | net/sunrpc/auth_null.c | 2 |
2 files changed, 87 insertions, 62 deletions
diff --git a/net/sunrpc/auth.c b/net/sunrpc/auth.c index 32985aa..c1576b1 100644 --- a/net/sunrpc/auth.c +++ b/net/sunrpc/auth.c @@ -291,25 +291,30 @@ rpcauth_release(struct rpc_auth *auth) static DEFINE_SPINLOCK(rpc_credcache_lock); -static void +/* + * On success, the caller is responsible for freeing the reference + * held by the hashtable + */ +static bool rpcauth_unhash_cred_locked(struct rpc_cred *cred) { + if (!test_and_clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags)) + return false; hlist_del_rcu(&cred->cr_hash); - smp_mb__before_atomic(); - clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags); + return true; } -static int +static bool rpcauth_unhash_cred(struct rpc_cred *cred) { spinlock_t *cache_lock; - int ret; + bool ret; + if (!test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags)) + return false; cache_lock = &cred->cr_auth->au_credcache->lock; spin_lock(cache_lock); - ret = atomic_read(&cred->cr_count) == 0; - if (ret) - rpcauth_unhash_cred_locked(cred); + ret = rpcauth_unhash_cred_locked(cred); spin_unlock(cache_lock); return ret; } @@ -388,6 +393,44 @@ void rpcauth_destroy_credlist(struct list_head *head) } } +static void +rpcauth_lru_add_locked(struct rpc_cred *cred) +{ + if (!list_empty(&cred->cr_lru)) + return; + number_cred_unused++; + list_add_tail(&cred->cr_lru, &cred_unused); +} + +static void +rpcauth_lru_add(struct rpc_cred *cred) +{ + if (!list_empty(&cred->cr_lru)) + return; + spin_lock(&rpc_credcache_lock); + rpcauth_lru_add_locked(cred); + spin_unlock(&rpc_credcache_lock); +} + +static void +rpcauth_lru_remove_locked(struct rpc_cred *cred) +{ + if (list_empty(&cred->cr_lru)) + return; + number_cred_unused--; + list_del_init(&cred->cr_lru); +} + +static void +rpcauth_lru_remove(struct rpc_cred *cred) +{ + if (list_empty(&cred->cr_lru)) + return; + spin_lock(&rpc_credcache_lock); + rpcauth_lru_remove_locked(cred); + spin_unlock(&rpc_credcache_lock); +} + /* * Clear the RPC credential cache, and delete those credentials * that are not referenced. @@ -407,13 +450,10 @@ rpcauth_clear_credcache(struct rpc_cred_cache *cache) head = &cache->hashtable[i]; while (!hlist_empty(head)) { cred = hlist_entry(head->first, struct rpc_cred, cr_hash); - get_rpccred(cred); - if (!list_empty(&cred->cr_lru)) { - list_del(&cred->cr_lru); - number_cred_unused--; - } - list_add_tail(&cred->cr_lru, &free); rpcauth_unhash_cred_locked(cred); + /* Note: We now hold a reference to cred */ + rpcauth_lru_remove_locked(cred); + list_add_tail(&cred->cr_lru, &free); } } spin_unlock(&cache->lock); @@ -447,7 +487,6 @@ EXPORT_SYMBOL_GPL(rpcauth_destroy_credcache); static long rpcauth_prune_expired(struct list_head *free, int nr_to_scan) { - spinlock_t *cache_lock; struct rpc_cred *cred, *next; unsigned long expired = jiffies - RPC_AUTH_EXPIRY_MORATORIUM; long freed = 0; @@ -456,32 +495,24 @@ rpcauth_prune_expired(struct list_head *free, int nr_to_scan) if (nr_to_scan-- == 0) break; + if (atomic_read(&cred->cr_count) > 1) { + rpcauth_lru_remove_locked(cred); + continue; + } /* * Enforce a 60 second garbage collection moratorium * Note that the cred_unused list must be time-ordered. */ - if (time_in_range(cred->cr_expire, expired, jiffies) && - test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) { - freed = SHRINK_STOP; - break; - } - - list_del_init(&cred->cr_lru); - number_cred_unused--; - freed++; - if (atomic_read(&cred->cr_count) != 0) + if (!time_in_range(cred->cr_expire, expired, jiffies)) + continue; + if (!rpcauth_unhash_cred(cred)) continue; - 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); + rpcauth_lru_remove_locked(cred); + freed++; + list_add_tail(&cred->cr_lru, free); } - return freed; + return freed ? freed : SHRINK_STOP; } static unsigned long @@ -595,6 +626,7 @@ rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred, if (cred == NULL) { cred = new; set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags); + atomic_inc(&cred->cr_count); hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]); } else list_add_tail(&new->cr_lru, &free); @@ -709,36 +741,29 @@ put_rpccred(struct rpc_cred *cred) { if (cred == NULL) return; - /* Fast path for unhashed credentials */ - if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) == 0) { + rcu_read_lock(); + if (atomic_dec_and_test(&cred->cr_count)) + goto destroy; + if (atomic_read(&cred->cr_count) != 1 || + !test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags)) + goto out; + if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0) { + cred->cr_expire = jiffies; + rpcauth_lru_add(cred); + /* Race breaker */ + if (unlikely(!test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags))) + rpcauth_lru_remove(cred); + } else if (rpcauth_unhash_cred(cred)) { + rpcauth_lru_remove(cred); if (atomic_dec_and_test(&cred->cr_count)) - cred->cr_ops->crdestroy(cred); - return; - } - - if (!atomic_dec_and_lock(&cred->cr_count, &rpc_credcache_lock)) - return; - if (!list_empty(&cred->cr_lru)) { - number_cred_unused--; - list_del_init(&cred->cr_lru); - } - if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) { - if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0) { - cred->cr_expire = jiffies; - list_add_tail(&cred->cr_lru, &cred_unused); - number_cred_unused++; - goto out_nodestroy; - } - if (!rpcauth_unhash_cred(cred)) { - /* We were hashed and someone looked us up... */ - goto out_nodestroy; - } + goto destroy; } - spin_unlock(&rpc_credcache_lock); - cred->cr_ops->crdestroy(cred); +out: + rcu_read_unlock(); return; -out_nodestroy: - spin_unlock(&rpc_credcache_lock); +destroy: + rcu_read_unlock(); + cred->cr_ops->crdestroy(cred); } EXPORT_SYMBOL_GPL(put_rpccred); diff --git a/net/sunrpc/auth_null.c b/net/sunrpc/auth_null.c index 4b48228..a7c00b4 100644 --- a/net/sunrpc/auth_null.c +++ b/net/sunrpc/auth_null.c @@ -138,6 +138,6 @@ 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), + .cr_count = ATOMIC_INIT(2), .cr_flags = 1UL << RPCAUTH_CRED_UPTODATE, }; |
