[PATCH v1 11/17] NFSD: Use xdrgen XDR functions for the NFS-ACL v2 NULL procedure

[Chuck Lever <cel@kernel.org>]

Hand-written XDR encoders and decoders are difficult to maintain
and can diverge from protocol specifications. Migrating to
xdrgen-generated code improves type safety and ensures the
implementation matches the NFS_ACL version 2 protocol description
exactly.

Convert the NULL procedure to use xdrgen_svc_decode_void and
xdrgen_svc_encode_void, generated from
Documentation/sunrpc/xdr/nfs_acl.x. NULL has no arguments or
results, so it is the first procedure converted.

NULL returns no XDR-encoded data, so pc_xdrressize is set to
XDR_void. The argzero field is also set to zero since xdrgen
decoders initialize all decoded values.

Signed-off-by: Chuck Lever <cel@kernel.org>
---
 fs/nfsd/nfs2acl.c | 32 +++++++++++++++++++-------------
 1 file changed, 19 insertions(+), 13 deletions(-)

diff --git a/fs/nfsd/nfs2acl.c b/fs/nfsd/nfs2acl.c
index c0bc77467e79..0698c9dc85dd 100644
--- a/fs/nfsd/nfs2acl.c
+++ b/fs/nfsd/nfs2acl.c
@@ -163,11 +163,17 @@ static __be32 nfsacld_map_status(__be32 status)
 	return status;
 }
 
-/*
- * NULL call.
+/**
+ * nfsacld_proc_null - NULL: Do nothing
+ * @rqstp: RPC transaction context
+ *
+ * Return:
+ *   %rpc_success:		RPC executed successfully
+ *
+ * RPC synopsis:
+ *   void ACLPROC2_NULL(void) = 0;
  */
-static __be32
-nfsacld_proc_null(struct svc_rqst *rqstp)
+static __be32 nfsacld_proc_null(struct svc_rqst *rqstp)
 {
 	return rpc_success;
 }
@@ -482,15 +488,15 @@ static void nfsaclsvc_release_setacl(struct svc_rqst *rqstp)
 
 static const struct svc_procedure nfsd_acl_procedures2[5] = {
 	[ACLPROC2_NULL] = {
-		.pc_func = nfsacld_proc_null,
-		.pc_decode = nfssvc_decode_voidarg,
-		.pc_encode = nfssvc_encode_voidres,
-		.pc_argsize = sizeof(struct nfsd_voidargs),
-		.pc_argzero = sizeof(struct nfsd_voidargs),
-		.pc_ressize = sizeof(struct nfsd_voidres),
-		.pc_cachetype = RC_NOCACHE,
-		.pc_xdrressize = ST,
-		.pc_name = "NULL",
+		.pc_func	= nfsacld_proc_null,
+		.pc_decode	= xdrgen_svc_decode_void,
+		.pc_encode	= xdrgen_svc_encode_void,
+		.pc_argsize	= XDR_void,
+		.pc_argzero	= 0,
+		.pc_ressize	= 0,
+		.pc_cachetype	= RC_NOCACHE,
+		.pc_xdrressize	= XDR_void,
+		.pc_name	= "NULL",
 	},
 	[ACLPROC2_GETACL] = {
 		.pc_func = nfsacld_proc_getacl,
-- 
2.56.0