From: Lennart Poettering <lennart@poettering.net>
Date: Wed, 19 Mar 2014 20:41:21 +0000 (+0100)
Subject: sd-bus: don't use assert_return() to check for disconnected bus connections
X-Git-Tag: v212~79
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=commitdiff_plain;h=a3d59cd1b0a2738d06893948492113f2c35be0af

sd-bus: don't use assert_return() to check for disconnected bus connections

A terminated connection is a runtime error and not a developer mistake,
hence don't use assert_return() to check for it.
---

diff --git a/src/libsystemd/sd-bus/bus-control.c b/src/libsystemd/sd-bus/bus-control.c
index bb6683eff..bd392a293 100644
--- a/src/libsystemd/sd-bus/bus-control.c
+++ b/src/libsystemd/sd-bus/bus-control.c
@@ -128,12 +128,14 @@ _public_ int sd_bus_request_name(sd_bus *bus, const char *name, uint64_t flags)
         assert_return(bus, -EINVAL);
         assert_return(name, -EINVAL);
         assert_return(bus->bus_client, -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
         assert_return(!bus_pid_changed(bus), -ECHILD);
         assert_return(!(flags & ~(SD_BUS_NAME_ALLOW_REPLACEMENT|SD_BUS_NAME_REPLACE_EXISTING|SD_BUS_NAME_QUEUE)), -EINVAL);
         assert_return(service_name_is_valid(name), -EINVAL);
         assert_return(name[0] != ':', -EINVAL);
 
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
         if (bus->is_kernel)
                 return bus_request_name_kernel(bus, name, flags);
         else
@@ -201,11 +203,13 @@ _public_ int sd_bus_release_name(sd_bus *bus, const char *name) {
         assert_return(bus, -EINVAL);
         assert_return(name, -EINVAL);
         assert_return(bus->bus_client, -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
         assert_return(!bus_pid_changed(bus), -ECHILD);
         assert_return(service_name_is_valid(name), -EINVAL);
         assert_return(name[0] != ':', -EINVAL);
 
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
         if (bus->is_kernel)
                 return bus_release_name_kernel(bus, name);
         else
@@ -342,9 +346,11 @@ static int bus_list_names_dbus1(sd_bus *bus, char ***acquired, char ***activatab
 _public_ int sd_bus_list_names(sd_bus *bus, char ***acquired, char ***activatable) {
         assert_return(bus, -EINVAL);
         assert_return(acquired || activatable, -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
         assert_return(!bus_pid_changed(bus), -ECHILD);
 
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
         if (bus->is_kernel)
                 return bus_list_names_kernel(bus, acquired, activatable);
         else
@@ -735,11 +741,13 @@ _public_ int sd_bus_get_owner(
         assert_return(name, -EINVAL);
         assert_return(mask <= _SD_BUS_CREDS_ALL, -ENOTSUP);
         assert_return(mask == 0 || creds, -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
         assert_return(!bus_pid_changed(bus), -ECHILD);
         assert_return(service_name_is_valid(name), -EINVAL);
         assert_return(bus->bus_client, -ENODATA);
 
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
         if (bus->is_kernel)
                 return bus_get_owner_kdbus(bus, name, mask, creds);
         else
@@ -1209,10 +1217,12 @@ _public_ int sd_bus_get_owner_machine_id(sd_bus *bus, const char *name, sd_id128
         assert_return(bus, -EINVAL);
         assert_return(name, -EINVAL);
         assert_return(machine, -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
         assert_return(!bus_pid_changed(bus), -ECHILD);
         assert_return(service_name_is_valid(name), -EINVAL);
 
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
         if (streq_ptr(name, bus->unique_name))
                 return sd_id128_get_machine(machine);
 
diff --git a/src/libsystemd/sd-bus/bus-convenience.c b/src/libsystemd/sd-bus/bus-convenience.c
index 6e02ad365..c5b9cd4ca 100644
--- a/src/libsystemd/sd-bus/bus-convenience.c
+++ b/src/libsystemd/sd-bus/bus-convenience.c
@@ -36,9 +36,11 @@ _public_ int sd_bus_emit_signal(
         int r;
 
         assert_return(bus, -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
         assert_return(!bus_pid_changed(bus), -ECHILD);
 
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
         r = sd_bus_message_new_signal(bus, &m, path, interface, member);
         if (r < 0)
                 return r;
@@ -70,9 +72,11 @@ _public_ int sd_bus_call_method(
         int r;
 
         assert_return(bus, -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
         assert_return(!bus_pid_changed(bus), -ECHILD);
 
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
         r = sd_bus_message_new_method_call(bus, &m, destination, path, interface, member);
         if (r < 0)
                 return r;
@@ -100,9 +104,12 @@ _public_ int sd_bus_reply_method_return(
         assert_return(call, -EINVAL);
         assert_return(call->sealed, -EPERM);
         assert_return(call->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL);
-        assert_return(call->bus && BUS_IS_OPEN(call->bus->state), -ENOTCONN);
+        assert_return(call->bus, -EINVAL);
         assert_return(!bus_pid_changed(call->bus), -ECHILD);
 
+        if (!BUS_IS_OPEN(call->bus->state))
+                return -ENOTCONN;
+
         if (call->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED)
                 return 0;
 
@@ -134,9 +141,12 @@ _public_ int sd_bus_reply_method_error(
         assert_return(call->sealed, -EPERM);
         assert_return(call->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL);
         assert_return(sd_bus_error_is_set(e), -EINVAL);
-        assert_return(call->bus && BUS_IS_OPEN(call->bus->state), -ENOTCONN);
+        assert_return(call->bus, -EINVAL);
         assert_return(!bus_pid_changed(call->bus), -ECHILD);
 
+        if (!BUS_IS_OPEN(call->bus->state))
+                return -ENOTCONN;
+
         if (call->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED)
                 return 0;
 
@@ -159,9 +169,12 @@ _public_ int sd_bus_reply_method_errorf(
         assert_return(call, -EINVAL);
         assert_return(call->sealed, -EPERM);
         assert_return(call->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL);
-        assert_return(call->bus && BUS_IS_OPEN(call->bus->state), -ENOTCONN);
+        assert_return(call->bus, -EINVAL);
         assert_return(!bus_pid_changed(call->bus), -ECHILD);
 
+        if (!BUS_IS_OPEN(call->bus->state))
+                return -ENOTCONN;
+
         if (call->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED)
                 return 0;
 
@@ -182,9 +195,12 @@ _public_ int sd_bus_reply_method_errno(
         assert_return(call, -EINVAL);
         assert_return(call->sealed, -EPERM);
         assert_return(call->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL);
-        assert_return(call->bus && BUS_IS_OPEN(call->bus->state), -ENOTCONN);
+        assert_return(call->bus, -EINVAL);
         assert_return(!bus_pid_changed(call->bus), -ECHILD);
 
+        if (!BUS_IS_OPEN(call->bus->state))
+                return -ENOTCONN;
+
         if (call->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED)
                 return 0;
 
@@ -208,9 +224,12 @@ _public_ int sd_bus_reply_method_errnof(
         assert_return(call, -EINVAL);
         assert_return(call->sealed, -EPERM);
         assert_return(call->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL);
-        assert_return(call->bus && BUS_IS_OPEN(call->bus->state), -ENOTCONN);
+        assert_return(call->bus, -EINVAL);
         assert_return(!bus_pid_changed(call->bus), -ECHILD);
 
+        if (!BUS_IS_OPEN(call->bus->state))
+                return -ENOTCONN;
+
         if (call->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED)
                 return 0;
 
@@ -239,9 +258,11 @@ _public_ int sd_bus_get_property(
         assert_return(member_name_is_valid(member), -EINVAL);
         assert_return(reply, -EINVAL);
         assert_return(signature_is_single(type, false), -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
         assert_return(!bus_pid_changed(bus), -ECHILD);
 
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
         r = sd_bus_call_method(bus, destination, path, "org.freedesktop.DBus.Properties", "Get", error, &rep, "ss", strempty(interface), member);
         if (r < 0)
                 return r;
@@ -273,9 +294,11 @@ _public_ int sd_bus_get_property_trivial(
         assert_return(member_name_is_valid(member), -EINVAL);
         assert_return(bus_type_is_trivial(type), -EINVAL);
         assert_return(ptr, -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
         assert_return(!bus_pid_changed(bus), -ECHILD);
 
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
         r = sd_bus_call_method(bus, destination, path, "org.freedesktop.DBus.Properties", "Get", error, &reply, "ss", strempty(interface), member);
         if (r < 0)
                 return r;
@@ -309,9 +332,11 @@ _public_ int sd_bus_get_property_string(
         assert_return(isempty(interface) || interface_name_is_valid(interface), -EINVAL);
         assert_return(member_name_is_valid(member), -EINVAL);
         assert_return(ret, -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
         assert_return(!bus_pid_changed(bus), -ECHILD);
 
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
         r = sd_bus_call_method(bus, destination, path, "org.freedesktop.DBus.Properties", "Get", error, &reply, "ss", strempty(interface), member);
         if (r < 0)
                 return r;
@@ -348,9 +373,11 @@ _public_ int sd_bus_get_property_strv(
         assert_return(isempty(interface) || interface_name_is_valid(interface), -EINVAL);
         assert_return(member_name_is_valid(member), -EINVAL);
         assert_return(ret, -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
         assert_return(!bus_pid_changed(bus), -ECHILD);
 
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
         r = sd_bus_call_method(bus, destination, path, "org.freedesktop.DBus.Properties", "Get", error, &reply, "ss", strempty(interface), member);
         if (r < 0)
                 return r;
@@ -383,9 +410,11 @@ _public_ int sd_bus_set_property(
         assert_return(isempty(interface) || interface_name_is_valid(interface), -EINVAL);
         assert_return(member_name_is_valid(member), -EINVAL);
         assert_return(signature_is_single(type, false), -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
         assert_return(!bus_pid_changed(bus), -ECHILD);
 
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
         r = sd_bus_message_new_method_call(bus, &m, destination, path, "org.freedesktop.DBus.Properties", "Set");
         if (r < 0)
                 return r;
@@ -416,9 +445,12 @@ _public_ int sd_bus_query_sender_creds(sd_bus_message *call, uint64_t mask, sd_b
 
         assert_return(call, -EINVAL);
         assert_return(call->sealed, -EPERM);
-        assert_return(call->bus && BUS_IS_OPEN(call->bus->state), -ENOTCONN);
+        assert_return(call->bus, -EINVAL);
         assert_return(!bus_pid_changed(call->bus), -ECHILD);
 
+        if (!BUS_IS_OPEN(call->bus->state))
+                return -ENOTCONN;
+
         c = sd_bus_message_get_creds(call);
 
         /* All data we need? */
diff --git a/src/libsystemd/sd-bus/bus-objects.c b/src/libsystemd/sd-bus/bus-objects.c
index 08792fea2..539cf2aad 100644
--- a/src/libsystemd/sd-bus/bus-objects.c
+++ b/src/libsystemd/sd-bus/bus-objects.c
@@ -2199,9 +2199,10 @@ _public_ int sd_bus_emit_properties_changed_strv(
         assert_return(bus, -EINVAL);
         assert_return(object_path_is_valid(path), -EINVAL);
         assert_return(interface_name_is_valid(interface), -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
         assert_return(!bus_pid_changed(bus), -ECHILD);
 
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
 
         /* A non-NULL but empty names list means nothing needs to be
            generated. A NULL list OTOH indicates that all properties
@@ -2244,9 +2245,11 @@ _public_ int sd_bus_emit_properties_changed(
         assert_return(bus, -EINVAL);
         assert_return(object_path_is_valid(path), -EINVAL);
         assert_return(interface_name_is_valid(interface), -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
         assert_return(!bus_pid_changed(bus), -ECHILD);
 
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
         if (!name)
                 return 0;
 
@@ -2364,9 +2367,11 @@ _public_ int sd_bus_emit_interfaces_added_strv(sd_bus *bus, const char *path, ch
 
         assert_return(bus, -EINVAL);
         assert_return(object_path_is_valid(path), -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
         assert_return(!bus_pid_changed(bus), -ECHILD);
 
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
         if (strv_isempty(interfaces))
                 return 0;
 
@@ -2424,9 +2429,11 @@ _public_ int sd_bus_emit_interfaces_added(sd_bus *bus, const char *path, const c
 
         assert_return(bus, -EINVAL);
         assert_return(object_path_is_valid(path), -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
         assert_return(!bus_pid_changed(bus), -ECHILD);
 
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
         interfaces = strv_from_stdarg_alloca(interface);
 
         return sd_bus_emit_interfaces_added_strv(bus, path, interfaces);
@@ -2438,9 +2445,11 @@ _public_ int sd_bus_emit_interfaces_removed_strv(sd_bus *bus, const char *path,
 
         assert_return(bus, -EINVAL);
         assert_return(object_path_is_valid(path), -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
         assert_return(!bus_pid_changed(bus), -ECHILD);
 
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
         if (strv_isempty(interfaces))
                 return 0;
 
@@ -2464,9 +2473,11 @@ _public_ int sd_bus_emit_interfaces_removed(sd_bus *bus, const char *path, const
 
         assert_return(bus, -EINVAL);
         assert_return(object_path_is_valid(path), -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
         assert_return(!bus_pid_changed(bus), -ECHILD);
 
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
         interfaces = strv_from_stdarg_alloca(interface);
 
         return sd_bus_emit_interfaces_removed_strv(bus, path, interfaces);
diff --git a/src/libsystemd/sd-bus/sd-bus.c b/src/libsystemd/sd-bus/sd-bus.c
index fa6d43adc..15c767723 100644
--- a/src/libsystemd/sd-bus/sd-bus.c
+++ b/src/libsystemd/sd-bus/sd-bus.c
@@ -1638,11 +1638,13 @@ static int bus_send_internal(sd_bus *bus, sd_bus_message *_m, uint64_t *cookie,
         int r;
 
         assert_return(bus, -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
         assert_return(m, -EINVAL);
         assert_return(!bus_pid_changed(bus), -ECHILD);
         assert_return(!bus->is_kernel || !(bus->hello_flags & KDBUS_HELLO_MONITOR), -EROFS);
 
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
         if (m->n_fds > 0) {
                 r = sd_bus_can_send(bus, SD_BUS_TYPE_UNIX_FD);
                 if (r < 0)
@@ -1718,10 +1720,12 @@ _public_ int sd_bus_send_to(sd_bus *bus, sd_bus_message *m, const char *destinat
         int r;
 
         assert_return(bus, -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
         assert_return(m, -EINVAL);
         assert_return(!bus_pid_changed(bus), -ECHILD);
 
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
         if (!streq_ptr(m->destination, destination)) {
 
                 if (!destination)
@@ -1773,7 +1777,6 @@ _public_ int sd_bus_call_async(
         int r;
 
         assert_return(bus, -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
         assert_return(m, -EINVAL);
         assert_return(m->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL);
         assert_return(!(m->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED), -EINVAL);
@@ -1781,6 +1784,9 @@ _public_ int sd_bus_call_async(
         assert_return(!bus_pid_changed(bus), -ECHILD);
         assert_return(!bus->is_kernel || !(bus->hello_flags & KDBUS_HELLO_MONITOR), -EROFS);
 
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
         r = hashmap_ensure_allocated(&bus->reply_callbacks, uint64_hash_func, uint64_compare_func);
         if (r < 0)
                 return r;
@@ -1887,7 +1893,6 @@ _public_ int sd_bus_call(
         int r;
 
         assert_return(bus, -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
         assert_return(m, -EINVAL);
         assert_return(m->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL);
         assert_return(!(m->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED), -EINVAL);
@@ -1895,6 +1900,9 @@ _public_ int sd_bus_call(
         assert_return(!bus_pid_changed(bus), -ECHILD);
         assert_return(!bus->is_kernel || !(bus->hello_flags & KDBUS_HELLO_MONITOR), -EROFS);
 
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
         r = bus_ensure_running(bus);
         if (r < 0)
                 return r;
@@ -2025,9 +2033,11 @@ _public_ int sd_bus_get_events(sd_bus *bus) {
         int flags = 0;
 
         assert_return(bus, -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state) || bus->state == BUS_CLOSING, -ENOTCONN);
         assert_return(!bus_pid_changed(bus), -ECHILD);
 
+        if (!BUS_IS_OPEN(bus->state) && bus->state != BUS_CLOSING)
+                return -ENOTCONN;
+
         if (bus->state == BUS_OPENING)
                 flags |= POLLOUT;
         else if (bus->state == BUS_AUTHENTICATING) {
@@ -2052,9 +2062,11 @@ _public_ int sd_bus_get_timeout(sd_bus *bus, uint64_t *timeout_usec) {
 
         assert_return(bus, -EINVAL);
         assert_return(timeout_usec, -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state) || bus->state == BUS_CLOSING, -ENOTCONN);
         assert_return(!bus_pid_changed(bus), -ECHILD);
 
+        if (!BUS_IS_OPEN(bus->state) && bus->state != BUS_CLOSING)
+                return -ENOTCONN;
+
         if (bus->track_queue) {
                 *timeout_usec = 0;
                 return 1;
@@ -2642,7 +2654,8 @@ static int bus_poll(sd_bus *bus, bool need_more, uint64_t timeout_usec) {
         if (bus->state == BUS_CLOSING)
                 return 1;
 
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
 
         e = sd_bus_get_events(bus);
         if (e < 0)
@@ -2697,7 +2710,8 @@ _public_ int sd_bus_wait(sd_bus *bus, uint64_t timeout_usec) {
         if (bus->state == BUS_CLOSING)
                 return 0;
 
-        assert_return(BUS_IS_OPEN(bus->state) , -ENOTCONN);
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
 
         if (bus->rqueue_size > 0)
                 return 0;
@@ -2714,7 +2728,8 @@ _public_ int sd_bus_flush(sd_bus *bus) {
         if (bus->state == BUS_CLOSING)
                 return 0;
 
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
 
         r = bus_ensure_running(bus);
         if (r < 0)
@@ -3224,9 +3239,13 @@ _public_ int sd_bus_get_peer_creds(sd_bus *bus, uint64_t mask, sd_bus_creds **re
         assert_return(bus, -EINVAL);
         assert_return(mask <= _SD_BUS_CREDS_ALL, -ENOTSUP);
         assert_return(ret, -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
         assert_return(!bus_pid_changed(bus), -ECHILD);
-        assert_return(!bus->is_kernel, -ENOTSUP);
+
+        if (!bus->is_kernel)
+                return -ENOTSUP;
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
 
         if (!bus->ucred_valid && !isempty(bus->label))
                 return -ENODATA;
@@ -3265,9 +3284,13 @@ _public_ int sd_bus_try_close(sd_bus *bus) {
         int r;
 
         assert_return(bus, -EINVAL);
-        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
         assert_return(!bus_pid_changed(bus), -ECHILD);
-        assert_return(bus->is_kernel, -ENOTSUP);
+
+        if (!bus->is_kernel)
+                return -ENOTSUP;
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
 
         if (bus->rqueue_size > 0)
                 return -EBUSY;