SUNRPC: Define rpcsec_gss_info structure

The NFSv4 SECINFO procedure returns a list of security flavors.  Any
GSS flavor also has a GSS tuple containing an OID, a quality-of-
protection value, and a service value, which specifies a particular
GSS pseudoflavor.

For simplicity and efficiency, I'd like to return each GSS tuple
from the NFSv4 SECINFO XDR decoder and pass it straight into the RPC
client.

Define a data structure that is visible to both the NFS client and
the RPC client.  Take structure and field names from the relevant
standards to avoid confusion.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 0b74489..a38fd17 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -5205,27 +5205,30 @@
 	return decode_op_hdr(xdr, OP_DELEGRETURN);
 }
 
-static int decode_secinfo_gss(struct xdr_stream *xdr, struct nfs4_secinfo_flavor *flavor)
+static int decode_secinfo_gss(struct xdr_stream *xdr,
+			      struct nfs4_secinfo4 *flavor)
 {
+	u32 oid_len;
 	__be32 *p;
 
 	p = xdr_inline_decode(xdr, 4);
 	if (unlikely(!p))
 		goto out_overflow;
-	flavor->gss.sec_oid4.len = be32_to_cpup(p);
-	if (flavor->gss.sec_oid4.len > GSS_OID_MAX_LEN)
+	oid_len = be32_to_cpup(p);
+	if (oid_len > GSS_OID_MAX_LEN)
 		goto out_err;
 
-	p = xdr_inline_decode(xdr, flavor->gss.sec_oid4.len);
+	p = xdr_inline_decode(xdr, oid_len);
 	if (unlikely(!p))
 		goto out_overflow;
-	memcpy(flavor->gss.sec_oid4.data, p, flavor->gss.sec_oid4.len);
+	memcpy(flavor->flavor_info.oid.data, p, oid_len);
+	flavor->flavor_info.oid.len = oid_len;
 
 	p = xdr_inline_decode(xdr, 8);
 	if (unlikely(!p))
 		goto out_overflow;
-	flavor->gss.qop4 = be32_to_cpup(p++);
-	flavor->gss.service = be32_to_cpup(p);
+	flavor->flavor_info.qop = be32_to_cpup(p++);
+	flavor->flavor_info.service = be32_to_cpup(p);
 
 	return 0;
 
@@ -5238,10 +5241,10 @@
 
 static int decode_secinfo_common(struct xdr_stream *xdr, struct nfs4_secinfo_res *res)
 {
-	struct nfs4_secinfo_flavor *sec_flavor;
+	struct nfs4_secinfo4 *sec_flavor;
+	unsigned int i, num_flavors;
 	int status;
 	__be32 *p;
-	int i, num_flavors;
 
 	p = xdr_inline_decode(xdr, 4);
 	if (unlikely(!p))