On 08/24/2018, 04:26 PM, Boris Ostrovsky wrote: > On 08/24/2018 07:26 AM, Juergen Gross wrote: >> On 24/08/18 13:12, Jiri Slaby wrote: >>> On 07/30/2018, 10:18 AM, Xiao Liang wrote: >>>> On 07/29/2018 11:30 PM, David Miller wrote: >>>>> From: Xiao Liang <xili...@redhat.com> >>>>> Date: Fri, 27 Jul 2018 17:56:08 +0800 >>>>> >>>>>> @@ -1330,6 +1331,11 @@ static struct net_device >>>>>> *xennet_create_dev(struct xenbus_device *dev) >>>>>> netif_carrier_off(netdev); >>>>>> xenbus_switch_state(dev, XenbusStateInitialising); >>>>>> + wait_event(module_load_q, >>>>>> + xenbus_read_driver_state(dev->otherend) != >>>>>> + XenbusStateClosed && >>>>>> + xenbus_read_driver_state(dev->otherend) != >>>>>> + XenbusStateUnknown); >>>>>> return netdev; >>>>>> exit: >>>>> What performs the wakeups that will trigger for this sleep site? >>>> In my understanding, backend leaving closed/unknow state can trigger the >>>> wakeups. I mean to make sure both sides are ready for creating connection. >>> While backporting this to 4.12, I was surprised by the commit the same >>> as Boris and David. >>> >>> So I assume the explanation is that wake_up_all of module_unload_q in >>> netback_changed wakes also all the processes waiting on module_load_q? >>> If so, what makes sure that module_unload_q is queued and the process is >>> the same as for module_load_q? >> How could it? Either the thread is waiting on module_unload_q _or_ on >> module_load_q. It can't wait on two queues at the same time. >> >>> To me, it looks rather error-prone. Unless it is erroneous now, at least >>> for future changes. Wouldn't it make sense to wake up module_load_q >>> along with module_unload_q in netback_changed? Or drop module_load_q >>> completely and use only module_unload_q (i.e. in xennet_create_dev too)? >> To me this looks just wrong. A thread waiting on module_load_q won't be >> woken up again. >> >> I'd drop module_load_q in favor of module_unload_q. > > > Yes, use single queue, but rename it to something more neutral. module_wq?
Can somebody who is actually using the module fix this, please? I could fix it, but untested changes are "a bit" worse than tested changes. thanks, -- js suse labs _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel