NFSD: Add common helpers to decode void args and encode void results

Start off the conversion to xdr_stream by de-duplicating the functions
that decode void arguments and encode void results.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Author: chucklever

fs/nfsd/nfs2acl.c

@@ -185,10 +185,6 @@ static __be32 nfsacld_proc_access(struct svc_rqst *rqstp)
 /*
  * XDR decode functions
  */
-static int nfsaclsvc_decode_voidarg(struct svc_rqst *rqstp, __be32 *p)
-{
-	return 1;
-}
 
 static int nfsaclsvc_decode_getaclargs(struct svc_rqst *rqstp, __be32 *p)
 {
@@ -255,15 +251,6 @@ static int nfsaclsvc_decode_accessargs(struct svc_rqst *rqstp, __be32 *p)
  * XDR encode functions
  */
 
-/*
- * There must be an encoding function for void results so svc_process
- * will work properly.
- */
-static int nfsaclsvc_encode_voidres(struct svc_rqst *rqstp, __be32 *p)
-{
-	return xdr_ressize_check(rqstp, p);
-}
-
 /* GETACL */
 static int nfsaclsvc_encode_getaclres(struct svc_rqst *rqstp, __be32 *p)
 {
@@ -378,10 +365,10 @@ struct nfsd3_voidargs { int dummy; };
 static const struct svc_procedure nfsd_acl_procedures2[5] = {
 	[ACLPROC2_NULL] = {
 		.pc_func = nfsacld_proc_null,
-		.pc_decode = nfsaclsvc_decode_voidarg,
-		.pc_encode = nfsaclsvc_encode_voidres,
-		.pc_argsize = sizeof(struct nfsd3_voidargs),
-		.pc_ressize = sizeof(struct nfsd3_voidargs),
+		.pc_decode = nfssvc_decode_voidarg,
+		.pc_encode = nfssvc_encode_voidres,
+		.pc_argsize = sizeof(struct nfsd_voidargs),
+		.pc_ressize = sizeof(struct nfsd_voidres),
 		.pc_cachetype = RC_NOCACHE,
 		.pc_xdrressize = ST,
 	},

fs/nfsd/nfs3acl.c

@@ -245,10 +245,10 @@ struct nfsd3_voidargs { int dummy; };
 static const struct svc_procedure nfsd_acl_procedures3[3] = {
 	[ACLPROC3_NULL] = {
 		.pc_func = nfsd3_proc_null,
-		.pc_decode = nfs3svc_decode_voidarg,
-		.pc_encode = nfs3svc_encode_voidres,
-		.pc_argsize = sizeof(struct nfsd3_voidargs),
-		.pc_ressize = sizeof(struct nfsd3_voidargs),
+		.pc_decode = nfssvc_decode_voidarg,
+		.pc_encode = nfssvc_encode_voidres,
+		.pc_argsize = sizeof(struct nfsd_voidargs),
+		.pc_ressize = sizeof(struct nfsd_voidres),
 		.pc_cachetype = RC_NOCACHE,
 		.pc_xdrressize = ST,
 	},

fs/nfsd/nfs3proc.c

@@ -692,8 +692,6 @@ nfsd3_proc_commit(struct svc_rqst *rqstp)
 #define nfsd3_attrstatres		nfsd3_attrstat
 #define nfsd3_wccstatres		nfsd3_attrstat
 #define nfsd3_createres			nfsd3_diropres
-#define nfsd3_voidres			nfsd3_voidargs
-struct nfsd3_voidargs { int dummy; };
 
 #define ST 1		/* status*/
 #define FH 17		/* filehandle with length */
@@ -704,10 +702,10 @@ struct nfsd3_voidargs { int dummy; };
 static const struct svc_procedure nfsd_procedures3[22] = {
 	[NFS3PROC_NULL] = {
 		.pc_func = nfsd3_proc_null,
-		.pc_decode = nfs3svc_decode_voidarg,
-		.pc_encode = nfs3svc_encode_voidres,
-		.pc_argsize = sizeof(struct nfsd3_voidargs),
-		.pc_ressize = sizeof(struct nfsd3_voidres),
+		.pc_decode = nfssvc_decode_voidarg,
+		.pc_encode = nfssvc_encode_voidres,
+		.pc_argsize = sizeof(struct nfsd_voidargs),
+		.pc_ressize = sizeof(struct nfsd_voidres),
 		.pc_cachetype = RC_NOCACHE,
 		.pc_xdrressize = ST,
 	},

fs/nfsd/nfs3xdr.c

@@ -304,11 +304,6 @@ void fill_post_wcc(struct svc_fh *fhp)
 /*
  * XDR decode functions
  */
-int
-nfs3svc_decode_voidarg(struct svc_rqst *rqstp, __be32 *p)
-{
-	return 1;
-}
 
 int
 nfs3svc_decode_fhandle(struct svc_rqst *rqstp, __be32 *p)
@@ -642,12 +637,6 @@ nfs3svc_decode_commitargs(struct svc_rqst *rqstp, __be32 *p)
  * XDR encode functions
  */
 
-int
-nfs3svc_encode_voidres(struct svc_rqst *rqstp, __be32 *p)
-{
-	return xdr_ressize_check(rqstp, p);
-}
-
 /* GETATTR */
 int
 nfs3svc_encode_attrstat(struct svc_rqst *rqstp, __be32 *p)

fs/nfsd/nfs4proc.c

@@ -3295,16 +3295,13 @@ static const char *nfsd4_op_name(unsigned opnum)
 	return "unknown_operation";
 }
 
-#define nfsd4_voidres			nfsd4_voidargs
-struct nfsd4_voidargs { int dummy; };
-
 static const struct svc_procedure nfsd_procedures4[2] = {
 	[NFSPROC4_NULL] = {
 		.pc_func = nfsd4_proc_null,
-		.pc_decode = nfs4svc_decode_voidarg,
-		.pc_encode = nfs4svc_encode_voidres,
-		.pc_argsize = sizeof(struct nfsd4_voidargs),
-		.pc_ressize = sizeof(struct nfsd4_voidres),
+		.pc_decode = nfssvc_decode_voidarg,
+		.pc_encode = nfssvc_encode_voidres,
+		.pc_argsize = sizeof(struct nfsd_voidargs),
+		.pc_ressize = sizeof(struct nfsd_voidres),
 		.pc_cachetype = RC_NOCACHE,
 		.pc_xdrressize = 1,
 	},

fs/nfsd/nfs4xdr.c

@@ -5271,12 +5271,6 @@ nfsd4_encode_replay(struct xdr_stream *xdr, struct nfsd4_op *op)
 	p = xdr_encode_opaque_fixed(p, rp->rp_buf, rp->rp_buflen);
 }
 
-int
-nfs4svc_encode_voidres(struct svc_rqst *rqstp, __be32 *p)
-{
-        return xdr_ressize_check(rqstp, p);
-}
-
 void nfsd4_release_compoundargs(struct svc_rqst *rqstp)
 {
 	struct nfsd4_compoundargs *args = rqstp->rq_argp;
@@ -5294,12 +5288,6 @@ void nfsd4_release_compoundargs(struct svc_rqst *rqstp)
 	}
 }
 
-int
-nfs4svc_decode_voidarg(struct svc_rqst *rqstp, __be32 *p)
-{
-	return 1;
-}
-
 int
 nfs4svc_decode_compoundargs(struct svc_rqst *rqstp, __be32 *p)
 {

fs/nfsd/nfsd.h

@@ -73,6 +73,14 @@ extern unsigned long		nfsd_drc_mem_used;
 
 extern const struct seq_operations nfs_exports_op;
 
+/*
+ * Common void argument and result helpers
+ */
+struct nfsd_voidargs { };
+struct nfsd_voidres { };
+int		nfssvc_decode_voidarg(struct svc_rqst *rqstp, __be32 *p);
+int		nfssvc_encode_voidres(struct svc_rqst *rqstp, __be32 *p);
+
 /*
  * Function prototypes.
  */

fs/nfsd/nfsproc.c

@@ -609,7 +609,6 @@ nfsd_proc_statfs(struct svc_rqst *rqstp)
  * NFSv2 Server procedures.
  * Only the results of non-idempotent operations are cached.
  */
-struct nfsd_void { int dummy; };
 
 #define ST 1		/* status */
 #define FH 8		/* filehandle */
@@ -618,10 +617,10 @@ struct nfsd_void { int dummy; };
 static const struct svc_procedure nfsd_procedures2[18] = {
 	[NFSPROC_NULL] = {
 		.pc_func = nfsd_proc_null,
-		.pc_decode = nfssvc_decode_void,
-		.pc_encode = nfssvc_encode_void,
-		.pc_argsize = sizeof(struct nfsd_void),
-		.pc_ressize = sizeof(struct nfsd_void),
+		.pc_decode = nfssvc_decode_voidarg,
+		.pc_encode = nfssvc_encode_voidres,
+		.pc_argsize = sizeof(struct nfsd_voidargs),
+		.pc_ressize = sizeof(struct nfsd_voidres),
 		.pc_cachetype = RC_NOCACHE,
 		.pc_xdrressize = 0,
 	},
@@ -647,10 +646,10 @@ static const struct svc_procedure nfsd_procedures2[18] = {
 	},
 	[NFSPROC_ROOT] = {
 		.pc_func = nfsd_proc_root,
-		.pc_decode = nfssvc_decode_void,
-		.pc_encode = nfssvc_encode_void,
-		.pc_argsize = sizeof(struct nfsd_void),
-		.pc_ressize = sizeof(struct nfsd_void),
+		.pc_decode = nfssvc_decode_voidarg,
+		.pc_encode = nfssvc_encode_voidres,
+		.pc_argsize = sizeof(struct nfsd_voidargs),
+		.pc_ressize = sizeof(struct nfsd_voidres),
 		.pc_cachetype = RC_NOCACHE,
 		.pc_xdrressize = 0,
 	},
@@ -685,10 +684,10 @@ static const struct svc_procedure nfsd_procedures2[18] = {
 	},
 	[NFSPROC_WRITECACHE] = {
 		.pc_func = nfsd_proc_writecache,
-		.pc_decode = nfssvc_decode_void,
-		.pc_encode = nfssvc_encode_void,
-		.pc_argsize = sizeof(struct nfsd_void),
-		.pc_ressize = sizeof(struct nfsd_void),
+		.pc_decode = nfssvc_decode_voidarg,
+		.pc_encode = nfssvc_encode_voidres,
+		.pc_argsize = sizeof(struct nfsd_voidargs),
+		.pc_ressize = sizeof(struct nfsd_voidres),
 		.pc_cachetype = RC_NOCACHE,
 		.pc_xdrressize = 0,
 	},

fs/nfsd/nfssvc.c

@@ -1075,6 +1075,34 @@ int nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
 	return 1;
 }
 
+/**
+ * nfssvc_decode_voidarg - Decode void arguments
+ * @rqstp: Server RPC transaction context
+ * @p: buffer containing arguments to decode
+ *
+ * Return values:
+ *   %0: Arguments were not valid
+ *   %1: Decoding was successful
+ */
+int nfssvc_decode_voidarg(struct svc_rqst *rqstp, __be32 *p)
+{
+	return 1;
+}
+
+/**
+ * nfssvc_encode_voidres - Encode void results
+ * @rqstp: Server RPC transaction context
+ * @p: buffer in which to encode results
+ *
+ * Return values:
+ *   %0: Local error while encoding
+ *   %1: Encoding was successful
+ */
+int nfssvc_encode_voidres(struct svc_rqst *rqstp, __be32 *p)
+{
+        return xdr_ressize_check(rqstp, p);
+}
+
 int nfsd_pool_stats_open(struct inode *inode, struct file *file)
 {
 	int ret;

fs/nfsd/nfsxdr.c

@@ -192,11 +192,6 @@ __be32 *nfs2svc_encode_fattr(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *f
 /*
  * XDR decode functions
  */
-int
-nfssvc_decode_void(struct svc_rqst *rqstp, __be32 *p)
-{
-	return xdr_argsize_check(rqstp, p);
-}
 
 int
 nfssvc_decode_fhandle(struct svc_rqst *rqstp, __be32 *p)
@@ -423,11 +418,6 @@ nfssvc_decode_readdirargs(struct svc_rqst *rqstp, __be32 *p)
 /*
  * XDR encode functions
  */
-int
-nfssvc_encode_void(struct svc_rqst *rqstp, __be32 *p)
-{
-	return xdr_ressize_check(rqstp, p);
-}
 
 int
 nfssvc_encode_stat(struct svc_rqst *rqstp, __be32 *p)