On Thursday, February 14, 2013 02:31:22 AM Moore, Robert wrote: > > > > I thought about that, but actually there's no guarantee that the > > > > handle will be valid after _EJ0 as far as I can say. So the race > > > > condition is going to be there anyway and using struct acpi_device > > > > just makes it easier to avoid it. > > > > > > In theory, yes, a stale handle could be a problem, if _EJ0 performs > > > unload table and if ACPICA frees up its internal data structure > > > pointed by the handle as a result. But we should not see such issue > > > now since we do not support dynamic ACPI namespace yet. > > > > I'm waiting for information from Bob about that. If we can assume ACPI > > handles to be always valid, that will simplify things quite a bit. > > If a table is unloaded, all the namespace nodes for that table are removed > from the namespace, and thus any ACPI_HANDLE pointers go stale and invalid.
OK, thanks! To me this means that we cannot assume a handle to stay valid between a notify handler and acpi_bus_hot_remove_device() run from a workqueue. Is there a mechanism in ACPICA to ensure that a handle won't become stale while a notify handler is running for it or is the OS responsible for ensuring that _EJ0 won't be run in parallel with notify handlers for device objects being ejected? Rafael -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
