diff options
Diffstat (limited to 'sys/xen/xenbus/xenbusb_back.c')
| -rw-r--r-- | sys/xen/xenbus/xenbusb_back.c | 104 |
1 files changed, 64 insertions, 40 deletions
diff --git a/sys/xen/xenbus/xenbusb_back.c b/sys/xen/xenbus/xenbusb_back.c index 32bbc04..1252abe 100644 --- a/sys/xen/xenbus/xenbusb_back.c +++ b/sys/xen/xenbus/xenbusb_back.c @@ -208,57 +208,79 @@ xenbusb_back_get_otherend_node(device_t dev, struct xenbus_device_ivars *ivars) if (error == 0) { ivars->xd_otherend_path = strdup(otherend_path, M_XENBUS); + ivars->xd_otherend_path_len = strlen(otherend_path); free(otherend_path, M_XENSTORE); } return (error); } /** - * \brief Backend XenBus child instance variable write access method. - * - * \param dev The NewBus device representing this XenBus bus. - * \param child The NewBus device representing a child of dev%'s XenBus bus. - * \param index The index of the instance variable to access. - * \param value The new value to set in the instance variable accessed. - * - * \return On success, 0. Otherwise an errno value indicating the - * type of failure. - * - * Xenbus_back overrides this method so that it can trap state transitions - * of local backend devices and clean up their XenStore entries as necessary - * during device instance teardown. + * \brief Backend XenBus method implementing responses to peer state changes. + * + * \param bus The XenBus bus parent of child. + * \param child The XenBus child whose peer stat has changed. + * \param state The current state of the peer. */ -static int -xenbusb_back_write_ivar(device_t dev, device_t child, int index, - uintptr_t value) +static void +xenbusb_back_otherend_changed(device_t bus, device_t child, + enum xenbus_state peer_state) { - int error; + /* Perform default processing of state. */ + xenbusb_otherend_changed(bus, child, peer_state); - error = xenbusb_write_ivar(dev, child, index, value); + /* + * "Online" devices are never fully detached in the + * newbus sense. Only the front<->back connection is + * torn down. If the front returns to the initialising + * state after closing a previous connection, signal + * our willingness to reconnect and that all necessary + * XenStore data for feature negotiation is present. + */ + if (peer_state == XenbusStateInitialising + && xenbus_dev_is_online(child) != 0 + && xenbus_get_state(child) == XenbusStateClosed) + xenbus_set_state(child, XenbusStateInitWait); +} - if (index == XENBUS_IVAR_STATE - && (enum xenbus_state)value == XenbusStateClosed - && xenbus_dev_is_online(child) == 0) { +/** + * \brief Backend XenBus method implementing responses to local + * XenStore changes. + * + * \param bus The XenBus bus parent of child. + * \param child The XenBus child whose peer stat has changed. + * \param_path The tree relative sub-path to the modified node. The empty + * string indicates the root of the tree was destroyed. + */ +static void +xenbusb_back_localend_changed(device_t bus, device_t child, const char *path) +{ - /* - * Cleanup the hotplug entry in the XenStore if - * present. The control domain expects any userland - * component associated with this device to destroy - * this node in order to signify it is safe to - * teardown the device. However, not all backends - * rely on userland components, and those that - * do should either use a communication channel - * other than the XenStore, or ensure the hotplug - * data is already cleaned up. - * - * This removal ensures that no matter what path - * is taken to mark a back-end closed, the control - * domain will understand that it is closed. - */ - xs_rm(XST_NIL, xenbus_get_node(child), "hotplug-status"); - } + xenbusb_localend_changed(bus, child, path); - return (error); + if (strcmp(path, "/state") != 0 + && strcmp(path, "/online") != 0) + return; + + if (xenbus_get_state(child) != XenbusStateClosed + || xenbus_dev_is_online(child) != 0) + return; + + /* + * Cleanup the hotplug entry in the XenStore if + * present. The control domain expects any userland + * component associated with this device to destroy + * this node in order to signify it is safe to + * teardown the device. However, not all backends + * rely on userland components, and those that + * do should either use a communication channel + * other than the XenStore, or ensure the hotplug + * data is already cleaned up. + * + * This removal ensures that no matter what path + * is taken to mark a back-end closed, the control + * domain will understand that it is closed. + */ + xs_rm(XST_NIL, xenbus_get_node(child), "hotplug-status"); } /*-------------------- Private Device Attachment Data -----------------------*/ @@ -275,7 +297,7 @@ static device_method_t xenbusb_back_methods[] = { /* Bus Interface */ DEVMETHOD(bus_print_child, xenbusb_print_child), DEVMETHOD(bus_read_ivar, xenbusb_read_ivar), - DEVMETHOD(bus_write_ivar, xenbusb_back_write_ivar), + DEVMETHOD(bus_write_ivar, xenbusb_write_ivar), DEVMETHOD(bus_alloc_resource, bus_generic_alloc_resource), DEVMETHOD(bus_release_resource, bus_generic_release_resource), DEVMETHOD(bus_activate_resource, bus_generic_activate_resource), @@ -284,6 +306,8 @@ static device_method_t xenbusb_back_methods[] = { /* XenBus Bus Interface */ DEVMETHOD(xenbusb_enumerate_type, xenbusb_back_enumerate_type), DEVMETHOD(xenbusb_get_otherend_node, xenbusb_back_get_otherend_node), + DEVMETHOD(xenbusb_otherend_changed, xenbusb_back_otherend_changed), + DEVMETHOD(xenbusb_localend_changed, xenbusb_back_localend_changed), { 0, 0 } }; |
