Re: [PATCH V3] ACPI / GED: unregister interrupts during shutdown

[Rafael J. Wysocki]

On Fri, Dec 8, 2017 at 5:40 AM, Sinan Kaya <okaya@xxxxxxxxxxxxxx> wrote:
> Some GED interrupts could be pending by the time we are doing a reboot.
>
> Even though GED driver uses devm_request_irq() to register the interrupt
> handler, the handler is not being freed on time during a shutdown since
> the driver is missing a shutdown callback.
>
> If the ACPI handler is no longer available, this causes an interrupt
> storm and delays shutdown.
>
> 1. Don't use devm family of functions for IRQ registration/free
> 2. Keep track of the events since free_irq() requires the dev_id parameter
> passed into the request_irq() function.
> 3. Call free_irq() on both remove and shutdown explicitly.
>
> Signed-off-by: Sinan Kaya <okaya@xxxxxxxxxxxxxx>
> ---
>  drivers/acpi/evged.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++------
>  1 file changed, 49 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/acpi/evged.c b/drivers/acpi/evged.c
> index 46f0603..38cb00e 100644
> --- a/drivers/acpi/evged.c
> +++ b/drivers/acpi/evged.c
> @@ -49,6 +49,11 @@
>
>  #define MODULE_NAME    "acpi-ged"
>
> +struct acpi_ged_device {
> +       struct device *dev;
> +       struct list_head event_list;
> +};
> +
>  struct acpi_ged_event {
>         struct list_head node;
>         struct device *dev;
> @@ -76,7 +81,8 @@ static acpi_status acpi_ged_request_interrupt(struct acpi_resource *ares,
>         unsigned int irq;
>         unsigned int gsi;
>         unsigned int irqflags = IRQF_ONESHOT;
> -       struct device *dev = context;
> +       struct acpi_ged_device *geddev = context;
> +       struct device *dev = geddev->dev;
>         acpi_handle handle = ACPI_HANDLE(dev);
>         acpi_handle evt_handle;
>         struct resource r;
> @@ -102,8 +108,6 @@ static acpi_status acpi_ged_request_interrupt(struct acpi_resource *ares,
>                 return AE_ERROR;
>         }
>
> -       dev_info(dev, "GED listening GSI %u @ IRQ %u\n", gsi, irq);
> -
>         event = devm_kzalloc(dev, sizeof(*event), GFP_KERNEL);
>         if (!event)
>                 return AE_ERROR;
> @@ -116,26 +120,63 @@ static acpi_status acpi_ged_request_interrupt(struct acpi_resource *ares,
>         if (r.flags & IORESOURCE_IRQ_SHAREABLE)
>                 irqflags |= IRQF_SHARED;
>
> -       if (devm_request_threaded_irq(dev, irq, NULL, acpi_ged_irq_handler,
> -                                     irqflags, "ACPI:Ged", event)) {
> +       if (request_threaded_irq(irq, NULL, acpi_ged_irq_handler,
> +                                irqflags, "ACPI:Ged", event)) {
>                 dev_err(dev, "failed to setup event handler for irq %u\n", irq);
>                 return AE_ERROR;
>         }
>
> +       dev_dbg(dev, "GED listening GSI %u @ IRQ %u\n", gsi, irq);
> +       list_add_tail(&event->node, &geddev->event_list);
>         return AE_OK;
>  }
>
>  static int ged_probe(struct platform_device *pdev)
>  {
> +       struct acpi_ged_device *geddev;
>         acpi_status acpi_ret;
>
> +       geddev = devm_kzalloc(&pdev->dev, sizeof(*geddev), GFP_KERNEL);
> +       if (!geddev)
> +               return -ENOMEM;
> +
> +       geddev->dev = &pdev->dev;
> +       INIT_LIST_HEAD(&geddev->event_list);
>         acpi_ret = acpi_walk_resources(ACPI_HANDLE(&pdev->dev), "_CRS",
> -                                      acpi_ged_request_interrupt, &pdev->dev);
> +                                      acpi_ged_request_interrupt, geddev);
>         if (ACPI_FAILURE(acpi_ret)) {
>                 dev_err(&pdev->dev, "unable to parse the _CRS record\n");
>                 return -EINVAL;
>         }
> +       platform_set_drvdata(pdev, geddev);
> +
> +       return 0;
> +}
> +
> +static void ged_cleanup_irq(struct acpi_ged_device *geddev)
> +{
> +       struct acpi_ged_event *event, *next;
> +
> +       list_for_each_entry_safe(event, next, &geddev->event_list, node) {
> +               free_irq(event->irq, event);
> +               list_del(&event->node);
> +               dev_dbg(geddev->dev, "GED releasing GSI %u @ IRQ %u\n",
> +                        event->gsi, event->irq);
> +       }
> +}
> +
> +static void ged_shutdown(struct platform_device *pdev)
> +{
> +       struct acpi_ged_device *geddev = platform_get_drvdata(pdev);
> +
> +       ged_cleanup_irq(geddev);
> +}
> +
> +static int ged_remove(struct platform_device *pdev)
> +{
> +       struct acpi_ged_device *geddev = platform_get_drvdata(pdev);
>
> +       ged_cleanup_irq(geddev);

Do you really need this duplication?  You may as well call
ged_shutdown() from here.

And the local variable is redundant too.

I guess it would be better to just fold ged_cleanup_irq() into
ged_shutdown() and call that from ged_remove().

>         return 0;
>  }
>
> @@ -146,6 +187,8 @@ static int ged_probe(struct platform_device *pdev)
>
>  static struct platform_driver ged_driver = {
>         .probe = ged_probe,
> +       .remove = ged_remove,
> +       .shutdown = ged_shutdown,
>         .driver = {
>                 .name = MODULE_NAME,
>                 .acpi_match_table = ACPI_PTR(ged_acpi_ids),
> --