SUNRPC: Add an rpc_credop callback for binding a credential to an rpc_task

We need the ability to treat 'generic' creds specially, since they want to
bind instances of the auth cred instead of binding themselves.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

include/linux/sunrpc/auth.h

@@ -112,6 +112,7 @@ struct rpc_credops {
 	void			(*crdestroy)(struct rpc_cred *);
 
 	int			(*crmatch)(struct auth_cred *, struct rpc_cred *, int);
+	void			(*crbind)(struct rpc_task *, struct rpc_cred *);
 	__be32 *		(*crmarshal)(struct rpc_task *, __be32 *);
 	int			(*crrefresh)(struct rpc_task *);
 	__be32 *		(*crvalidate)(struct rpc_task *, __be32 *);
@@ -139,6 +140,7 @@ struct rpc_cred *	rpcauth_lookup_credcache(struct rpc_auth *, struct auth_cred *
 void			rpcauth_init_cred(struct rpc_cred *, const struct auth_cred *, struct rpc_auth *, const struct rpc_credops *);
 struct rpc_cred *	rpcauth_lookupcred(struct rpc_auth *, int);
 void			rpcauth_bindcred(struct rpc_task *, struct rpc_cred *, int);
+void			rpcauth_generic_bind_cred(struct rpc_task *, struct rpc_cred *);
 void			put_rpccred(struct rpc_cred *);
 void			rpcauth_unbindcred(struct rpc_task *);
 __be32 *		rpcauth_marshcred(struct rpc_task *, __be32 *);

net/sunrpc/auth.c

@@ -375,13 +375,14 @@ rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
 }
 EXPORT_SYMBOL_GPL(rpcauth_init_cred);
 
-static void
+void
 rpcauth_generic_bind_cred(struct rpc_task *task, struct rpc_cred *cred)
 {
 	task->tk_msg.rpc_cred = get_rpccred(cred);
 	dprintk("RPC: %5u holding %s cred %p\n", task->tk_pid,
 			cred->cr_auth->au_ops->au_name, cred);
 }
+EXPORT_SYMBOL_GPL(rpcauth_generic_bind_cred);
 
 static void
 rpcauth_bind_root_cred(struct rpc_task *task)
@@ -421,7 +422,7 @@ void
 rpcauth_bindcred(struct rpc_task *task, struct rpc_cred *cred, int flags)
 {
 	if (cred != NULL)
-		rpcauth_generic_bind_cred(task, cred);
+		cred->cr_ops->crbind(task, cred);
 	else if (flags & RPC_TASK_ROOTCREDS)
 		rpcauth_bind_root_cred(task);
 	else

net/sunrpc/auth_generic.c

@@ -35,6 +35,20 @@ struct rpc_cred *rpc_lookup_cred(void)
 }
 EXPORT_SYMBOL_GPL(rpc_lookup_cred);
 
+static void
+generic_bind_cred(struct rpc_task *task, struct rpc_cred *cred)
+{
+	struct rpc_auth *auth = task->tk_client->cl_auth;
+	struct auth_cred *acred = &container_of(cred, struct generic_cred, gc_base)->acred;
+	struct rpc_cred *ret;
+
+	ret = auth->au_ops->lookup_cred(auth, acred, 0);
+	if (!IS_ERR(ret))
+		task->tk_msg.rpc_cred = ret;
+	else
+		task->tk_status = PTR_ERR(ret);
+}
+
 /*
  * Lookup generic creds for current process
  */
@@ -138,5 +152,6 @@ static struct rpc_auth generic_auth = {
 static const struct rpc_credops generic_credops = {
 	.cr_name = "Generic cred",
 	.crdestroy = generic_destroy_cred,
+	.crbind = generic_bind_cred,
 	.crmatch = generic_match,
 };

net/sunrpc/auth_gss/auth_gss.c

@@ -1300,6 +1300,7 @@ static const struct rpc_credops gss_credops = {
 	.cr_name	= "AUTH_GSS",
 	.crdestroy	= gss_destroy_cred,
 	.cr_init	= gss_cred_init,
+	.crbind		= rpcauth_generic_bind_cred,
 	.crmatch	= gss_match,
 	.crmarshal	= gss_marshal,
 	.crrefresh	= gss_refresh,
@@ -1311,6 +1312,7 @@ static const struct rpc_credops gss_credops = {
 static const struct rpc_credops gss_nullops = {
 	.cr_name	= "AUTH_GSS",
 	.crdestroy	= gss_destroy_cred,
+	.crbind		= rpcauth_generic_bind_cred,
 	.crmatch	= gss_match,
 	.crmarshal	= gss_marshal,
 	.crrefresh	= gss_refresh_null,

net/sunrpc/auth_null.c

@@ -125,6 +125,7 @@ static
 const struct rpc_credops null_credops = {
 	.cr_name	= "AUTH_NULL",
 	.crdestroy	= nul_destroy_cred,
+	.crbind		= rpcauth_generic_bind_cred,
 	.crmatch	= nul_match,
 	.crmarshal	= nul_marshal,
 	.crrefresh	= nul_refresh,

net/sunrpc/auth_unix.c

@@ -237,6 +237,7 @@ static
 const struct rpc_credops unix_credops = {
 	.cr_name	= "AUTH_UNIX",
 	.crdestroy	= unx_destroy_cred,
+	.crbind		= rpcauth_generic_bind_cred,
 	.crmatch	= unx_match,
 	.crmarshal	= unx_marshal,
 	.crrefresh	= unx_refresh,