NFSPROC4_CLNT_CB_SEQUENCE,
 };
 
+#define to_delegation(cb) \
+       container_of(cb, struct nfs4_delegation, dl_recall)
+
 struct nfs4_cb_compound_hdr {
        /* args */
        u32             ident;  /* minorversion 0 only */
 static void nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, struct xdr_stream *xdr,
                                   const struct nfsd4_callback *cb)
 {
-       const struct nfs4_delegation *args = cb->cb_op;
+       const struct nfs4_delegation *dp = to_delegation(cb);
        struct nfs4_cb_compound_hdr hdr = {
                .ident = cb->cb_clp->cl_cb_ident,
                .minorversion = cb->cb_minorversion,
 
        encode_cb_compound4args(xdr, &hdr);
        encode_cb_sequence4args(xdr, cb, &hdr);
-       encode_cb_recall4args(xdr, args, &hdr);
+       encode_cb_recall4args(xdr, dp, &hdr);
        encode_cb_nops(&hdr);
 }
 
 {
        struct nfsd4_callback *cb = &clp->cl_cb_null;
 
-       cb->cb_op = NULL;
        cb->cb_clp = clp;
 
        cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_NULL];
        }
 }
 
-
 static void nfsd4_cb_recall_done(struct rpc_task *task, void *calldata)
 {
        struct nfsd4_callback *cb = calldata;
-       struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
+       struct nfs4_delegation *dp = to_delegation(cb);
        struct nfs4_client *clp = cb->cb_clp;
        struct rpc_clnt *current_rpc_client = clp->cl_cb_client;
 
 {
        struct nfsd4_callback *cb = calldata;
        struct nfs4_client *clp = cb->cb_clp;
-       struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
 
        if (cb->cb_done) {
+               struct nfs4_delegation *dp = to_delegation(cb);
+
                spin_lock(&clp->cl_lock);
                list_del(&cb->cb_per_client);
                spin_unlock(&clp->cl_lock);
        struct nfsd4_callback *cb = container_of(w, struct nfsd4_callback,
                                                        cb_work);
 
-       nfsd4_prepare_cb_recall(cb->cb_op);
+       nfsd4_prepare_cb_recall(to_delegation(cb));
        nfsd4_run_callback_rpc(cb);
 }
 
        struct nfs4_client *clp = dp->dl_stid.sc_client;
 
        dp->dl_retries = 1;
-       cb->cb_op = dp;
        cb->cb_clp = clp;
        cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_RECALL];
        cb->cb_msg.rpc_argp = cb;