diff options
| -rw-r--r-- | drivers/xen/xenbus/xenbus_client.c | 13 | ||||
| -rw-r--r-- | drivers/xen/xenbus/xenbus_probe.c | 36 | ||||
| -rw-r--r-- | include/xen/xenbus.h | 1 |
3 files changed, 48 insertions, 2 deletions
diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c index e502435145ae..19672b08a680 100644 --- a/drivers/xen/xenbus/xenbus_client.c +++ b/drivers/xen/xenbus/xenbus_client.c @@ -226,8 +226,9 @@ __xenbus_switch_state(struct xenbus_device *dev, struct xenbus_transaction xbt; int current_state; int err, abort; + bool vanished = false; - if (state == dev->state) + if (state == dev->state || dev->vanished) return 0; again: @@ -242,6 +243,10 @@ again: err = xenbus_scanf(xbt, dev->nodename, "state", "%d", ¤t_state); if (err != 1) goto abort; + if (current_state != dev->state && current_state == XenbusStateInitialising) { + vanished = true; + goto abort; + } err = xenbus_printf(xbt, dev->nodename, "state", "%d", state); if (err) { @@ -256,7 +261,7 @@ abort: if (err == -EAGAIN && !abort) goto again; xenbus_switch_fatal(dev, depth, err, "ending transaction"); - } else + } else if (!vanished) dev->state = state; return 0; @@ -941,6 +946,10 @@ enum xenbus_state xenbus_read_driver_state(const struct xenbus_device *dev, const char *path) { enum xenbus_state result; + + if (dev && dev->vanished) + return XenbusStateUnknown; + int err = xenbus_gather(XBT_NIL, path, "state", "%d", &result, NULL); if (err) result = XenbusStateUnknown; diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c index 2eed06ba5d38..eb260eceb4d2 100644 --- a/drivers/xen/xenbus/xenbus_probe.c +++ b/drivers/xen/xenbus/xenbus_probe.c @@ -444,6 +444,9 @@ static void xenbus_cleanup_devices(const char *path, struct bus_type *bus) info.dev = NULL; bus_for_each_dev(bus, NULL, &info, cleanup_dev); if (info.dev) { + dev_warn(&info.dev->dev, + "device forcefully removed from xenstore\n"); + info.dev->vanished = true; device_unregister(&info.dev->dev); put_device(&info.dev->dev); } @@ -659,6 +662,39 @@ void xenbus_dev_changed(const char *node, struct xen_bus_type *bus) return; dev = xenbus_device_find(root, &bus->bus); + /* + * Backend domain crash results in not coordinated frontend removal, + * without going through XenbusStateClosing. If this is a new instance + * of the same device Xen tools will have reset the state to + * XenbusStateInitializing. + * It might be that the backend crashed early during the init phase of + * device setup, in which case the known state would have been + * XenbusStateInitializing. So test the backend domid to match the + * saved one. In case the new backend happens to have the same domid as + * the old one, we can just carry on, as there is no inconsistency + * resulting in this case. + */ + if (dev && !strcmp(bus->root, "device")) { + enum xenbus_state state = xenbus_read_driver_state(dev, dev->nodename); + unsigned int backend = xenbus_read_unsigned(root, "backend-id", + dev->otherend_id); + + if (state == XenbusStateInitialising && + (state != dev->state || backend != dev->otherend_id)) { + /* + * State has been reset, assume the old one vanished + * and new one needs to be probed. + */ + dev_warn(&dev->dev, + "state reset occurred, reconnecting\n"); + dev->vanished = true; + } + if (dev->vanished) { + device_unregister(&dev->dev); + put_device(&dev->dev); + dev = NULL; + } + } if (!dev) xenbus_probe_node(bus, type, root); else diff --git a/include/xen/xenbus.h b/include/xen/xenbus.h index 15319da65b7f..8ca15743af7f 100644 --- a/include/xen/xenbus.h +++ b/include/xen/xenbus.h @@ -80,6 +80,7 @@ struct xenbus_device { const char *devicetype; const char *nodename; const char *otherend; + bool vanished; int otherend_id; struct xenbus_watch otherend_watch; struct device dev; |