RPC: Clean up RPC task structure

 Shrink the RPC task structure. Instead of storing separate pointers
 for task->tk_exit and task->tk_release, put them in a structure.

 Also pass the user data pointer as a parameter instead of passing it via
 task->tk_calldata. This enables us to nest callbacks.

 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 583c071..cf92008 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -53,7 +53,7 @@
 #define NFSPROC4_CB_COMPOUND 1
 
 /* declarations */
-static void nfs4_cb_null(struct rpc_task *task);
+static const struct rpc_call_ops nfs4_cb_null_ops;
 
 /* Index of predefined Linux callback client operations */
 
@@ -447,7 +447,7 @@
 	msg.rpc_cred = nfsd4_lookupcred(clp,0);
 	if (IS_ERR(msg.rpc_cred))
 		goto out_rpciod;
-	status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, nfs4_cb_null, NULL);
+	status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, &nfs4_cb_null_ops, NULL);
 	put_rpccred(msg.rpc_cred);
 
 	if (status != 0) {
@@ -469,7 +469,7 @@
 }
 
 static void
-nfs4_cb_null(struct rpc_task *task)
+nfs4_cb_null(struct rpc_task *task, void *dummy)
 {
 	struct nfs4_client *clp = (struct nfs4_client *)task->tk_msg.rpc_argp;
 	struct nfs4_callback *cb = &clp->cl_callback;
@@ -488,6 +488,10 @@
 	put_nfs4_client(clp);
 }
 
+static const struct rpc_call_ops nfs4_cb_null_ops = {
+	.rpc_call_done = nfs4_cb_null,
+};
+
 /*
  * called with dp->dl_count inc'ed.
  * nfs4_lock_state() may or may not have been called.