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xen: introduce separate XenWatchList for XenDevice objects

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This patch uses the XenWatchList abstraction to add a separate watch list
for each device. This is more scalable than walking a single notifier
list for all watches and is also necessary to implement a bug-fix in a
subsequent patch.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Anthony Perard <anthony.perard@citrix.com>
Message-Id: <20190913082159.31338-3-paul.durrant@citrix.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
This commit is contained in:
Paul Durrant 2019-09-13 09:21:57 +01:00 committed by Anthony PERARD
parent 374752a26b
commit d198b711f9
3 changed files with 62 additions and 14 deletions
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2
hw/xen/trace-events
View File

@ -29,6 +29,8 @@ xen_device_backend_changed(const char *type, char *name) "type: %s name: %s"
xen_device_frontend_state(const char *type, char *name, const char *state) "type: %s name: %s -> %s"
xen_device_frontend_changed(const char *type, char *name) "type: %s name: %s"
xen_device_unplug(const char *type, char *name) "type: %s name: %s"
xen_device_add_watch(const char *type, char *name, const char *node, const char *key) "type: %s name: %s node: %s key: %s"
xen_device_remove_watch(const char *type, char *name, const char *node, const char *key) "type: %s name: %s node: %s key: %s"
# xen-bus-helper.c
xs_node_create(const char *node) "%s"

72
hw/xen/xen-bus.c
View File

@ -235,11 +235,11 @@ static void watch_list_remove(XenWatchList *watch_list, XenWatch *watch,
static XenWatch *xen_bus_add_watch(XenBus *xenbus, const char *node,
const char *key, XenWatchHandler handler,
void *opaque, Error **errp)
Error **errp)
{
trace_xen_bus_add_watch(node, key);
return watch_list_add(xenbus->watch_list, node, key, handler, opaque,
return watch_list_add(xenbus->watch_list, node, key, handler, xenbus,
errp);
}
@ -433,7 +433,7 @@ static void xen_bus_realize(BusState *bus, Error **errp)
xenbus->backend_watch =
xen_bus_add_watch(xenbus, "", /* domain root node */
"backend", xen_bus_enumerate, xenbus, &local_err);
"backend", xen_bus_enumerate, &local_err);
if (local_err) {
/* This need not be treated as a hard error so don't propagate */
error_reportf_err(local_err,
@ -621,6 +621,31 @@ static void xen_device_backend_changed(void *opaque)
}
}
static XenWatch *xen_device_add_watch(XenDevice *xendev, const char *node,
const char *key,
XenWatchHandler handler,
Error **errp)
{
const char *type = object_get_typename(OBJECT(xendev));
trace_xen_device_add_watch(type, xendev->name, node, key);
return watch_list_add(xendev->watch_list, node, key, handler, xendev,
errp);
}
static void xen_device_remove_watch(XenDevice *xendev, XenWatch *watch,
Error **errp)
{
const char *type = object_get_typename(OBJECT(xendev));
trace_xen_device_remove_watch(type, xendev->name, watch->node,
watch->key);
watch_list_remove(xendev->watch_list, watch, errp);
}
static void xen_device_backend_create(XenDevice *xendev, Error **errp)
{
XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
@ -645,9 +670,9 @@ static void xen_device_backend_create(XenDevice *xendev, Error **errp)
}
xendev->backend_state_watch =
xen_bus_add_watch(xenbus, xendev->backend_path,
"state", xen_device_backend_changed,
xendev, &local_err);
xen_device_add_watch(xendev, xendev->backend_path,
"state", xen_device_backend_changed,
&local_err);
if (local_err) {
error_propagate_prepend(errp, local_err,
"failed to watch backend state: ");
@ -655,9 +680,9 @@ static void xen_device_backend_create(XenDevice *xendev, Error **errp)
}
xendev->backend_online_watch =
xen_bus_add_watch(xenbus, xendev->backend_path,
"online", xen_device_backend_changed,
xendev, &local_err);
xen_device_add_watch(xendev, xendev->backend_path,
"online", xen_device_backend_changed,
&local_err);
if (local_err) {
error_propagate_prepend(errp, local_err,
"failed to watch backend online: ");
@ -671,12 +696,12 @@ static void xen_device_backend_destroy(XenDevice *xendev)
Error *local_err = NULL;
if (xendev->backend_online_watch) {
xen_bus_remove_watch(xenbus, xendev->backend_online_watch, NULL);
xen_device_remove_watch(xendev, xendev->backend_online_watch, NULL);
xendev->backend_online_watch = NULL;
}
if (xendev->backend_state_watch) {
xen_bus_remove_watch(xenbus, xendev->backend_state_watch, NULL);
xen_device_remove_watch(xendev, xendev->backend_state_watch, NULL);
xendev->backend_state_watch = NULL;
}
@ -812,8 +837,8 @@ static void xen_device_frontend_create(XenDevice *xendev, Error **errp)
}
xendev->frontend_state_watch =
xen_bus_add_watch(xenbus, xendev->frontend_path, "state",
xen_device_frontend_changed, xendev, &local_err);
xen_device_add_watch(xendev, xendev->frontend_path, "state",
xen_device_frontend_changed, &local_err);
if (local_err) {
error_propagate_prepend(errp, local_err,
"failed to watch frontend state: ");
@ -826,7 +851,8 @@ static void xen_device_frontend_destroy(XenDevice *xendev)
Error *local_err = NULL;
if (xendev->frontend_state_watch) {
xen_bus_remove_watch(xenbus, xendev->frontend_state_watch, NULL);
xen_device_remove_watch(xendev, xendev->frontend_state_watch,
NULL);
xendev->frontend_state_watch = NULL;
}
@ -1122,6 +1148,16 @@ static void xen_device_unrealize(DeviceState *dev, Error **errp)
xendev->xgth = NULL;
}
if (xendev->watch_list) {
watch_list_destroy(xendev->watch_list);
xendev->watch_list = NULL;
}
if (xendev->xsh) {
xs_close(xendev->xsh);
xendev->xsh = NULL;
}
g_free(xendev->name);
xendev->name = NULL;
}
@ -1164,6 +1200,14 @@ static void xen_device_realize(DeviceState *dev, Error **errp)
trace_xen_device_realize(type, xendev->name);
xendev->xsh = xs_open(0);
if (!xendev->xsh) {
error_setg_errno(errp, errno, "failed xs_open");
goto unrealize;
}
xendev->watch_list = watch_list_create(xendev->xsh);
xendev->xgth = xengnttab_open(NULL, 0);
if (!xendev->xgth) {
error_setg_errno(errp, errno, "failed xengnttab_open");

2
include/hw/xen/xen-bus.h
View File

@ -22,6 +22,8 @@ typedef struct XenDevice {
DeviceState qdev;
domid_t frontend_id;
char *name;
struct xs_handle *xsh;
XenWatchList *watch_list;
char *backend_path, *frontend_path;
enum xenbus_state backend_state, frontend_state;
Notifier exit;