From bd95608053b7f7813351b0defc0e3e7ef8cf2803 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Mon, 14 Jul 2014 11:28:20 +1000 Subject: sunrpc/auth: allow lockless (rcu) lookup of credential cache. The new flag RPCAUTH_LOOKUP_RCU to credential lookup avoids locking, does not take a reference on the returned credential, and returns -ECHILD if a simple lookup was not possible. The returned value can only be used within an rcu_read_lock protected region. The main user of this is the new rpc_lookup_cred_nonblock() which returns a pointer to the current credential which is only rcu-safe (no ref-count held), and might return -ECHILD if allocation was required. Signed-off-by: NeilBrown Signed-off-by: Trond Myklebust --- net/sunrpc/auth_null.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'net/sunrpc/auth_null.c') diff --git a/net/sunrpc/auth_null.c b/net/sunrpc/auth_null.c index f0ebe07978a2..712c123e04e9 100644 --- a/net/sunrpc/auth_null.c +++ b/net/sunrpc/auth_null.c @@ -35,6 +35,8 @@ nul_destroy(struct rpc_auth *auth) static struct rpc_cred * nul_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags) { + if (flags & RPCAUTH_LOOKUP_RCU) + return &null_cred; return get_rpccred(&null_cred); } -- cgit v1.2.3