SUNRPC: introduce helpers for reference counted rpcbind clients
SUNRPC: introduce helpers for reference counted rpcbind clients

v6:
1) added write memory barrier to rpcb_set_local to make sure, that rpcbind
clients become valid before rpcb_users assignment
2) explicitly set rpcb_users to 1 instead of incrementing it (looks clearer from
my pow).

v5: fixed races with rpcb_users in rpcb_get_local()

This helpers will be used for dynamical creation and destruction of rpcbind
clients.
Variable rpcb_users is actually a counter of lauched RPC services. If rpcbind
clients has been created already, then we just increase rpcb_users.

Signed-off-by: Stanislav Kinsbursky <43b28e187c4fe6e53d7ab0bb71957481e322f182@parallels.com>
Signed-off-by: Trond Myklebust <6a1f9db795c9fc44be97d66ab114c53193bd3d13@netapp.com>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas