Alan Stern [mailto:stern@xxxxxxxxxxxxxxxxxxx] writes: > On Thu, 4 Mar 2010, Hugh Daschbach wrote: > >> Is there some way I can detect that devn no longer points to a valid >> device upon return from dev->*->shutdown(dev)? Or, where else can I >> look to better understand your suggestion? > > Did you read the patch in my previous message? You didn't quote it. > It removes the devn variable, so the problem you're worried about > cannot occur. > > Alan Stern Mea culpa. I looked but did not see. I have tested your patch. It does solve my problem. I've attached my version, with comments as you suggested, below. I have added get_device()/put_device() to ensure there's the device hasn't fully disappeared before calling list_del_init(). Is this needed? If so, there's "might_sleep()" commented out in put_device(). Do I need to release the lock before calling put_device()? Thanks for you patience. Hugh diff --git a/drivers/base/core.c b/drivers/base/core.c index 2820257..1133d7a 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -1731,10 +1731,20 @@ EXPORT_SYMBOL_GPL(device_move); */ void device_shutdown(void) { - struct device *dev, *devn; + struct device *dev; + + spin_lock(&devices_kset->list_lock); + /* + * Walk the devices list backward, shutting down each in turn. + * Beware that device unplug events may also start pulling + * devices offline, even as the system is shutting down. + */ + while (!list_empty(&devices_kset->list)) { + dev = list_entry(devices_kset->list.prev, struct device, + kobj.entry); + get_device(dev); + spin_unlock(&devices_kset->list_lock); - list_for_each_entry_safe_reverse(dev, devn, &devices_kset->list, - kobj.entry) { if (dev->bus && dev->bus->shutdown) { dev_dbg(dev, "shutdown\n"); dev->bus->shutdown(dev); @@ -1742,6 +1752,15 @@ void device_shutdown(void) dev_dbg(dev, "shutdown\n"); dev->driver->shutdown(dev); } + + /* + * Make sure the device iss off the kset list, in the + * event that dev->*->shutdown() didn't remove it. + */ + spin_lock(&devices_kset->list_lock); + list_del_init(&dev->kobj.entry); + put_device(dev); } + spin_unlock(&devices_kset->list_lock); async_synchronize_full(); } -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
