SUNRPC: Fix a deadlock in rpc_client_register()
SUNRPC: Fix a deadlock in rpc_client_register()

Commit 384816051ca9125cd54750e59c780c2a2655fa4f (SUNRPC: fix races on
PipeFS MOUNT notifications) introduces a regression when we call
rpc_setup_pipedir() with RPCSEC_GSS as the auth flavour.

By calling rpcauth_create() while holding the sn->pipefs_sb_lock, we
end up deadlocking in gss_pipes_dentries_create_net().
Fix is to register the client and release the mutex before calling
rpcauth_create().

Reported-by: Weston Andros Adamson <2782014720c8dba08f7eb23e9f1d190c445c0c94@netapp.com>
Tested-by: Weston Andros Adamson <2782014720c8dba08f7eb23e9f1d190c445c0c94@netapp.com>
Cc: Stanislav Kinsbursky <43b28e187c4fe6e53d7ab0bb71957481e322f182@parallels.com>
Cc: <4fbacc2fa0ffdbb11bf1ad6925b886ebd08dd15f@vger.kernel.org> # : 3848160: SUNRPC: fix races on PipeFS MOUNT
Cc: <4fbacc2fa0ffdbb11bf1ad6925b886ebd08dd15f@vger.kernel.org> # : e73f4cc: SUNRPC: split client creation
Signed-off-by: Trond Myklebust <6a1f9db795c9fc44be97d66ab114c53193bd3d13@netapp.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs