SUNRPC: Add enum svc_auth_status

In addition to the benefits of using an enum rather than a set of
macros, we now have a named type that can improve static type
checking of function return values.

As part of this change, I removed a stale comment from svcauth.h;
the return values from current implementations of the
auth_ops::release method are all zero/negative errno, not the SVC_OK
enum values as the old comment suggested.

Suggested-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

4 files changed, 40 insertions, 17 deletions

diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
index c4a566737085cd..18734e70c5ddb1 100644
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -986,7 +986,7 @@ bad_unwrap:
 	return -EINVAL;
 }
 
-static int
+static enum svc_auth_status
 svcauth_gss_set_client(struct svc_rqst *rqstp)
 {
 	struct gss_svc_data *svcdata = rqstp->rq_auth_data;
@@ -1634,7 +1634,7 @@ svcauth_gss_decode_credbody(struct xdr_stream *xdr,
  *
  * The rqstp->rq_auth_stat field is also set (see RFCs 2203 and 5531).
  */
-static int
+static enum svc_auth_status
 svcauth_gss_accept(struct svc_rqst *rqstp)
 {
 	struct gss_svc_data *svcdata = rqstp->rq_auth_data;
@@ -1945,9 +1945,6 @@ bad_wrap:
  *    %0: the Reply is ready to be sent
  *    %-ENOMEM: failed to allocate memory
  *    %-EINVAL: encoding error
- *
- * XXX: These return values do not match the return values documented
- *      for the auth_ops ->release method in linux/sunrpc/svcauth.h.
  */
 static int
 svcauth_gss_release(struct svc_rqst *rqstp)
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 030f8c759ee603..7873a3ff24a832 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1275,8 +1275,9 @@ svc_process_common(struct svc_rqst *rqstp)
 	const struct svc_procedure *procp = NULL;
 	struct svc_serv		*serv = rqstp->rq_server;
 	struct svc_process_info process;
-	int			auth_res, rc;
+	enum svc_auth_status	auth_res;
 	unsigned int		aoffset;
+	int			rc;
 	__be32			*p;
 
 	/* Will be turned off by GSS integrity and privacy services */
@@ -1331,6 +1332,9 @@ svc_process_common(struct svc_rqst *rqstp)
 		goto dropit;
 	case SVC_COMPLETE:
 		goto sendit;
+	default:
+		pr_warn_once("Unexpected svc_auth_status (%d)\n", auth_res);
+		goto err_system_err;
 	}
 
 	if (progp == NULL)
diff --git a/net/sunrpc/svcauth.c b/net/sunrpc/svcauth.c
index 67d8245a08afb7..aa4429d0b8106a 100644
--- a/net/sunrpc/svcauth.c
+++ b/net/sunrpc/svcauth.c
@@ -60,8 +60,19 @@ svc_put_auth_ops(struct auth_ops *aops)
 	module_put(aops->owner);
 }
 
-int
-svc_authenticate(struct svc_rqst *rqstp)
+/**
+ * svc_authenticate - Initialize an outgoing credential
+ * @rqstp: RPC execution context
+ *
+ * Return values:
+ *   %SVC_OK: XDR encoding of the result can begin
+ *   %SVC_DENIED: Credential or verifier is not valid
+ *   %SVC_GARBAGE: Failed to decode credential or verifier
+ *   %SVC_COMPLETE: GSS context lifetime event; no further action
+ *   %SVC_DROP: Drop this request; no further action
+ *   %SVC_CLOSE: Like drop, but also close transport connection
+ */
+enum svc_auth_status svc_authenticate(struct svc_rqst *rqstp)
 {
 	struct auth_ops *aops;
 	u32 flavor;
@@ -89,16 +100,28 @@ svc_authenticate(struct svc_rqst *rqstp)
 }
 EXPORT_SYMBOL_GPL(svc_authenticate);
 
-int svc_set_client(struct svc_rqst *rqstp)
+/**
+ * svc_set_client - Assign an appropriate 'auth_domain' as the client
+ * @rqstp: RPC execution context
+ *
+ * Return values:
+ *   %SVC_OK: Client was found and assigned
+ *   %SVC_DENY: Client was explicitly denied
+ *   %SVC_DROP: Ignore this request
+ *   %SVC_CLOSE: Ignore this request and close the connection
+ */
+enum svc_auth_status svc_set_client(struct svc_rqst *rqstp)
 {
 	rqstp->rq_client = NULL;
 	return rqstp->rq_authop->set_client(rqstp);
 }
 EXPORT_SYMBOL_GPL(svc_set_client);
 
-/* A request, which was authenticated, has now executed.
- * Time to finalise the credentials and verifier
- * and release and resources
+/**
+ * svc_authorise - Finalize credentials/verifier and release resources
+ * @rqstp: RPC execution context
+ *
+ * Returns zero on success, or a negative errno.
  */
 int svc_authorise(struct svc_rqst *rqstp)
 {
diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c
index 174783f804fa56..04b45588ae6fee 100644
--- a/net/sunrpc/svcauth_unix.c
+++ b/net/sunrpc/svcauth_unix.c
@@ -665,7 +665,7 @@ static struct group_info *unix_gid_find(kuid_t uid, struct svc_rqst *rqstp)
 	}
 }
 
-int
+enum svc_auth_status
 svcauth_unix_set_client(struct svc_rqst *rqstp)
 {
 	struct sockaddr_in *sin;
@@ -736,7 +736,6 @@ out:
 	rqstp->rq_auth_stat = rpc_auth_ok;
 	return SVC_OK;
 }
-
 EXPORT_SYMBOL_GPL(svcauth_unix_set_client);
 
 /**
@@ -751,7 +750,7 @@ EXPORT_SYMBOL_GPL(svcauth_unix_set_client);
  *
  * rqstp->rq_auth_stat is set as mandated by RFC 5531.
  */
-static int
+static enum svc_auth_status
 svcauth_null_accept(struct svc_rqst *rqstp)
 {
 	struct xdr_stream *xdr = &rqstp->rq_arg_stream;
@@ -828,7 +827,7 @@ struct auth_ops svcauth_null = {
  *
  * rqstp->rq_auth_stat is set as mandated by RFC 5531.
  */
-static int
+static enum svc_auth_status
 svcauth_tls_accept(struct svc_rqst *rqstp)
 {
 	struct xdr_stream *xdr = &rqstp->rq_arg_stream;
@@ -913,7 +912,7 @@ struct auth_ops svcauth_tls = {
  *
  * rqstp->rq_auth_stat is set as mandated by RFC 5531.
  */
-static int
+static enum svc_auth_status
 svcauth_unix_accept(struct svc_rqst *rqstp)
 {
 	struct xdr_stream *xdr = &rqstp->rq_arg_stream;