NFSD: Add a separate decoder for ssv_sp_parms

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

fs/nfsd/nfs4xdr.c

@@ -1488,12 +1488,54 @@ nfsd4_decode_state_protect_ops(struct nfsd4_compoundargs *argp,
 	return nfs_ok;
 }
 
+/*
+ * This implementation currently does not support SP4_SSV.
+ * This decoder simply skips over these arguments.
+ */
+static noinline __be32
+nfsd4_decode_ssv_sp_parms(struct nfsd4_compoundargs *argp,
+			  struct nfsd4_exchange_id *exid)
+{
+	u32 count, window, num_gss_handles;
+	__be32 status;
+
+	/* ssp_ops */
+	status = nfsd4_decode_state_protect_ops(argp, exid);
+	if (status)
+		return status;
+
+	/* ssp_hash_algs<> */
+	if (xdr_stream_decode_u32(argp->xdr, &count) < 0)
+		return nfserr_bad_xdr;
+	while (count--) {
+		status = nfsd4_decode_ignored_string(argp, 0);
+		if (status)
+			return status;
+	}
+
+	/* ssp_encr_algs<> */
+	if (xdr_stream_decode_u32(argp->xdr, &count) < 0)
+		return nfserr_bad_xdr;
+	while (count--) {
+		status = nfsd4_decode_ignored_string(argp, 0);
+		if (status)
+			return status;
+	}
+
+	if (xdr_stream_decode_u32(argp->xdr, &window) < 0)
+		return nfserr_bad_xdr;
+	if (xdr_stream_decode_u32(argp->xdr, &num_gss_handles) < 0)
+		return nfserr_bad_xdr;
+
+	return nfs_ok;
+}
+
 static __be32
 nfsd4_decode_exchange_id(struct nfsd4_compoundargs *argp,
 			 struct nfsd4_exchange_id *exid)
 {
-	int dummy, tmp;
 	DECODE_HEAD;
+	int dummy;
 
 	READ_BUF(NFS4_VERIFIER_SIZE);
 	COPYMEM(exid->verifier.data, NFS4_VERIFIER_SIZE);
@@ -1517,33 +1559,9 @@ nfsd4_decode_exchange_id(struct nfsd4_compoundargs *argp,
 			return status;
 		break;
 	case SP4_SSV:
-		/* ssp_ops */
-		status = nfsd4_decode_state_protect_ops(argp, exid);
+		status = nfsd4_decode_ssv_sp_parms(argp, exid);
 		if (status)
 			return status;
-
-		/* ssp_hash_algs<> */
-		READ_BUF(4);
-		tmp = be32_to_cpup(p++);
-		while (tmp--) {
-			READ_BUF(4);
-			dummy = be32_to_cpup(p++);
-			READ_BUF(dummy);
-			p += XDR_QUADLEN(dummy);
-		}
-
-		/* ssp_encr_algs<> */
-		READ_BUF(4);
-		tmp = be32_to_cpup(p++);
-		while (tmp--) {
-			READ_BUF(4);
-			dummy = be32_to_cpup(p++);
-			READ_BUF(dummy);
-			p += XDR_QUADLEN(dummy);
-		}
-
-		/* ignore ssp_window and ssp_num_gss_handles: */
-		READ_BUF(8);
 		break;
 	default:
 		goto xdr_error;