On Tue, Apr 10, 2012 at 4:43 AM, Kenji Kaneshige
<kaneshige.kenji@xxxxxxxxxxxxxx> wrote:
> I think you're rignt.
>
> Reviewed-by: Kenji Kaneshige <kaneshige.kenji@xxxxxxxxxxxxxx>
>
> (2012/04/08 3:18), Jiang Liu wrote:
>> When destroying a PCIe hotplug controller, all work items associated with
>> that controller should be flushed. Function pcie_cleanup_slot() calls
>> cancel_delayed_work() and flush_workqueue() to achieve that.
>> Function flush_workqueue() will flush all work items already submitted,
>> but new work items submitted by those already submitted work items may
>> still be in live state when returning from flush_workqueue().
>>
>> For the extreme case, pciehp driver may expierence following calling path:
>> 1) pcie_isr() -> pciehp_handle_xxx() -> queue_interrupt_event()->queue_work()
>> 2) interrupt_event_handler() -> handle_button_press_event() ->
>> queue_delayed_work()
>> 3) pciehp_queue_pushbutton_work() -> queue_work()
>>
>> So enhance pcie_cleanup_slot() to correctly flush workqueue when destroying
>> PCIe hotplug controller.
>>
>> Signed-off-by: Jiang Liu<jiang.liu@xxxxxxxxxx>
>> ---
>> drivers/pci/hotplug/pciehp_hpc.c | 13 ++++++++++++-
>> 1 files changed, 12 insertions(+), 1 deletions(-)
>>
>> diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
>> index d4fa705..9a48a51 100644
>> --- a/drivers/pci/hotplug/pciehp_hpc.c
>> +++ b/drivers/pci/hotplug/pciehp_hpc.c
>> @@ -890,8 +890,19 @@ static int pcie_init_slot(struct controller *ctrl)
>> static void pcie_cleanup_slot(struct controller *ctrl)
>> {
>> struct slot *slot = ctrl->slot;
>> - cancel_delayed_work(&slot->work);
>> +
>> + /*
>> + * Following workqueue flushing logic is to deal with the special call path:
>> + * 1) pcie_isr() -> pciehp_handle_xxx() ->
>> + * queue_interrupt_event(pciehp_wq_event)->queue_work(pciehp_wq)
>> + * 2) interrupt_event_handler() -> handle_button_press_event() ->
>> + * queue_delayed_work(pciehp_wq)
>> + * 3) pciehp_queue_pushbutton_work() -> queue_work(pciehp_wq)
>> + */
>> flush_workqueue(pciehp_wq);
>> + cancel_delayed_work_sync(&slot->work);
>> + flush_workqueue(pciehp_wq);
>> +
>> kfree(slot);
>> }
Jiang, I'm ignoring this (and the next [2/2] patch) because I assume
they're superceded by the "[PATCH RFC 00/17] Introduce a global lock
to serialize all PCI hotplug" series of April 16. Let me know if
otherwise.
Bjorn
--
To unsubscribe from this list: send the line "unsubscribe linux-pci" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
