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 --- include/linux/sunrpc/auth.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/sunrpc') diff --git a/include/linux/sunrpc/auth.h b/include/linux/sunrpc/auth.h index c683b9a06913..8e030075fe79 100644 --- a/include/linux/sunrpc/auth.h +++ b/include/linux/sunrpc/auth.h @@ -103,6 +103,7 @@ struct rpc_auth_create_args { /* Flags for rpcauth_lookupcred() */ #define RPCAUTH_LOOKUP_NEW 0x01 /* Accept an uninitialised cred */ +#define RPCAUTH_LOOKUP_RCU 0x02 /* lock-less lookup */ /* * Client authentication ops @@ -154,6 +155,7 @@ void rpc_destroy_generic_auth(void); void rpc_destroy_authunix(void); struct rpc_cred * rpc_lookup_cred(void); +struct rpc_cred * rpc_lookup_cred_nonblock(void); struct rpc_cred * rpc_lookup_machine_cred(const char *service_name); int rpcauth_register(const struct rpc_authops *); int rpcauth_unregister(const struct rpc_authops *); -- cgit v1.2.3