On Thursday, November 01, 2012 01:16:22 PM Yinghai Lu wrote: > On Thu, Nov 1, 2012 at 1:17 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote: > > On Thursday, November 01, 2012 01:17:58 PM Toshi Kani wrote: > >> On Thu, 2012-11-01 at 11:28 -0700, Yinghai Lu wrote: > >> > On Thu, Nov 1, 2012 at 9:43 AM, Toshi Kani <toshi.kani@xxxxxx> wrote: > >> > > > >> > > Rafael pointed out in my CPU hot-remove patch that > >> > > acpi_bus_hot_remove_device() was not exported for modules. Looks like > >> > > you have the same problem here. FYI, I just sent the following patch > >> > > that exports acpi_bus_hot_remove_device() and acpi_os_hotplug_execute(). > >> > > > >> > > https://lkml.org/lkml/2012/11/1/225 > >> > > >> > acpi_os_hotplug_execute() does not like having good quality yet. > >> > > >> > c02256be (Zhang Rui 2009-06-23 10:20:29 +0800 941) /* > >> > c02256be (Zhang Rui 2009-06-23 10:20:29 +0800 942) * We > >> > can't run hotplug code in keventd_wq/kacpid_wq/kacpid_notify_wq > >> > c02256be (Zhang Rui 2009-06-23 10:20:29 +0800 943) * > >> > because the hotplug code may call driver .remove() functions, > >> > c02256be (Zhang Rui 2009-06-23 10:20:29 +0800 944) * > >> > which invoke flush_scheduled_work/acpi_os_wait_events_complete > >> > c02256be (Zhang Rui 2009-06-23 10:20:29 +0800 945) * to > >> > flush these workqueues. > >> > c02256be (Zhang Rui 2009-06-23 10:20:29 +0800 946) */ > >> > c02256be (Zhang Rui 2009-06-23 10:20:29 +0800 947) queue > >> > = hp ? kacpi_hotplug_wq : > >> > c02256be (Zhang Rui 2009-06-23 10:20:29 +0800 948) > >> > (type == OSL_NOTIFY_HANDLER ? kacpi_notify_wq : kacpid_wq); > >> > 9ac61856 (Bjorn Helgaas 2009-08-31 22:32:10 +0000 949) > >> > dpc->wait = hp ? 1 : 0; > >> > bc73675b (Zhang Rui 2010-03-22 15:48:54 +0800 950) > >> > bc73675b (Zhang Rui 2010-03-22 15:48:54 +0800 951) if > >> > (queue == kacpi_hotplug_wq) > >> > bc73675b (Zhang Rui 2010-03-22 15:48:54 +0800 952) > >> > INIT_WORK(&dpc->work, acpi_os_execute_deferred); > >> > bc73675b (Zhang Rui 2010-03-22 15:48:54 +0800 953) else > >> > if (queue == kacpi_notify_wq) > >> > bc73675b (Zhang Rui 2010-03-22 15:48:54 +0800 954) > >> > INIT_WORK(&dpc->work, acpi_os_execute_deferred); > >> > bc73675b (Zhang Rui 2010-03-22 15:48:54 +0800 955) else > >> > bc73675b (Zhang Rui 2010-03-22 15:48:54 +0800 956) > >> > INIT_WORK(&dpc->work, acpi_os_execute_deferred); > >> > bc73675b (Zhang Rui 2010-03-22 15:48:54 +0800 957) > >> > > >> > really don't know why checking queue and call same code in every branch. > >> > > >> > from comm: > >> > > >> > commit bc73675b99fd9850dd914be01d71af99c5d2a1ae > >> > Author: Zhang Rui <rui.zhang@xxxxxxxxx> > >> > Date: Mon Mar 22 15:48:54 2010 +0800 > >> > > >> > ACPI: fixes a false alarm from lockdep > >> > > >> > fixes a false alarm from lockdep, as acpi hotplug workqueue waits other > >> > workqueues. > >> > http://bugzilla.kernel.org/show_bug.cgi?id=14553 > >> > https://bugzilla.kernel.org/show_bug.cgi?id=15521 > >> > > >> > Original-patch-from: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > >> > Signed-off-by: Shaohua Li <shaohua.li@xxxxxxxxx> > >> > Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx> > >> > Signed-off-by: Len Brown <len.brown@xxxxxxxxx> > >> > > >> > diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c > >> > index 8e6d866..900da68 100644 > >> > --- a/drivers/acpi/osl.c > >> > +++ b/drivers/acpi/osl.c > >> > @@ -758,7 +758,14 @@ static acpi_status > >> > __acpi_os_execute(acpi_execute_type type, > >> > queue = hp ? kacpi_hotplug_wq : > >> > (type == OSL_NOTIFY_HANDLER ? kacpi_notify_wq : kacpid_wq); > >> > dpc->wait = hp ? 1 : 0; > >> > - INIT_WORK(&dpc->work, acpi_os_execute_deferred); > >> > + > >> > + if (queue == kacpi_hotplug_wq) > >> > + INIT_WORK(&dpc->work, acpi_os_execute_deferred); > >> > + else if (queue == kacpi_notify_wq) > >> > + INIT_WORK(&dpc->work, acpi_os_execute_deferred); > >> > + else > >> > + INIT_WORK(&dpc->work, acpi_os_execute_deferred); > >> > + > >> > ret = queue_work(queue, &dpc->work); > >> > > >> > if (!ret) { > >> > > >> > > >> > Len or Rafael, > >> > can you just revert that silly patch? > >> > >> Hi Yinghai, > >> > >> Per the following thread, the code seems to be written in this way to > >> allocate a separate lock_class_key for each work queue. It should have > >> had some comment to explain this, though. > >> > >> https://lkml.org/lkml/2009/12/13/304 > > > > The code has evolved since then, however, so that it doesn't make sense > > any more. > > > > oh, no, that commit should not be reverted. instead we should add some > comment for it... > > that mean : three path, will have three separated static lock dep key > from every INIT_WORK. I see. OK, I'll drop the patch removing it. What about the following comment: "To prevent lockdep from complaining unnecessarily, make sure that there is a different static lockdep key created for each workqueue by using INIT_WORK for each of them separately." Thanks, Rafael -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
