nfsd: fix decoder callback prototypes

Declare the p_decode callbacks with the proper prototype instead of
casting to kxdrdproc_t and losing all type safety.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jeff Layton <jlayton@redhat.com>

fs/nfsd/nfs4callback.c

@@ -513,8 +513,9 @@ static int nfs4_xdr_dec_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
  */
 static int nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp,
 				  struct xdr_stream *xdr,
-				  struct nfsd4_callback *cb)
+				  void *data)
 {
+	struct nfsd4_callback *cb = data;
 	struct nfs4_cb_compound_hdr hdr;
 	int status;
 
@@ -604,8 +605,9 @@ static void nfs4_xdr_enc_cb_layout(struct rpc_rqst *req,
 
 static int nfs4_xdr_dec_cb_layout(struct rpc_rqst *rqstp,
 				  struct xdr_stream *xdr,
-				  struct nfsd4_callback *cb)
+				  void *data)
 {
+	struct nfsd4_callback *cb = data;
 	struct nfs4_cb_compound_hdr hdr;
 	int status;
 
@@ -662,8 +664,9 @@ static void nfs4_xdr_enc_cb_notify_lock(struct rpc_rqst *req,
 
 static int nfs4_xdr_dec_cb_notify_lock(struct rpc_rqst *rqstp,
 					struct xdr_stream *xdr,
-					struct nfsd4_callback *cb)
+					void *data)
 {
+	struct nfsd4_callback *cb = data;
 	struct nfs4_cb_compound_hdr hdr;
 	int status;
 
@@ -686,7 +689,7 @@ static int nfs4_xdr_dec_cb_notify_lock(struct rpc_rqst *rqstp,
 [NFSPROC4_CLNT_##proc] = {						\
 	.p_proc    = NFSPROC4_CB_##call,				\
 	.p_encode  = nfs4_xdr_enc_##argtype,		\
-	.p_decode  = (kxdrdproc_t)nfs4_xdr_dec_##restype,		\
+	.p_decode  = nfs4_xdr_dec_##restype,				\
 	.p_arglen  = NFS4_enc_##argtype##_sz,				\
 	.p_replen  = NFS4_dec_##restype##_sz,				\
 	.p_statidx = NFSPROC4_CB_##call,				\