On Wed, Sep 23, 2020 at 11:47 AM Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> A struct device is a dynamic structure, with reference counting.
> "Tricking" the kernel to make a dynamic structure static, by working
> around the driver core release detection logic, is not nice.
>
> Because of this, this code has been used as an example for others on
> "how to do things", which is just about the worst thing possible to have
> happen.
>
> Fix this all up by making the platform device dynamic and providing a
> real release function.
>
> Cc: Rajneesh Bhardwaj <rajneesh.bhardwaj@xxxxxxxxx>
> Cc: Vishwanath Somayaji <vishwanath.somayaji@xxxxxxxxx>
> Cc: Darren Hart <dvhart@xxxxxxxxxxxxx>
> Cc: Andy Shevchenko <andy@xxxxxxxxxxxxx>
> Cc: Rajat Jain <rajatja@xxxxxxxxxx>
> Cc: platform-driver-x86@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Reported-by: Maximilian Luz <luzmaximilian@xxxxxxxxx>
> Fixes: b02f6a2ef0a1 ("platform/x86: intel_pmc_core: Attach using APCI HID "INT33A1"")
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Acked-by: Rajat Jain <rajatja@xxxxxxxxxx>
> ---
> drivers/platform/x86/intel_pmc_core_pltdrv.c | 26 +++++++++++++-------
> 1 file changed, 17 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/platform/x86/intel_pmc_core_pltdrv.c b/drivers/platform/x86/intel_pmc_core_pltdrv.c
> index 731281855cc8..73797680b895 100644
> --- a/drivers/platform/x86/intel_pmc_core_pltdrv.c
> +++ b/drivers/platform/x86/intel_pmc_core_pltdrv.c
> @@ -20,15 +20,10 @@
>
> static void intel_pmc_core_release(struct device *dev)
> {
> - /* Nothing to do. */
> + kfree(dev);
> }
>
> -static struct platform_device pmc_core_device = {
> - .name = "intel_pmc_core",
> - .dev = {
> - .release = intel_pmc_core_release,
> - },
> -};
> +static struct platform_device *pmc_core_device;
>
> /*
> * intel_pmc_core_platform_ids is the list of platforms where we want to
> @@ -52,6 +47,8 @@ MODULE_DEVICE_TABLE(x86cpu, intel_pmc_core_platform_ids);
>
> static int __init pmc_core_platform_init(void)
> {
> + int retval;
> +
> /* Skip creating the platform device if ACPI already has a device */
> if (acpi_dev_present("INT33A1", NULL, -1))
> return -ENODEV;
> @@ -59,12 +56,23 @@ static int __init pmc_core_platform_init(void)
> if (!x86_match_cpu(intel_pmc_core_platform_ids))
> return -ENODEV;
>
> - return platform_device_register(&pmc_core_device);
> + pmc_core_device = kzalloc(sizeof(*pmc_core_device), GFP_KERNEL);
> + if (!pmc_core_device)
> + return -ENOMEM;
> +
> + pmc_core_device->name = "intel_pmc_core";
> + pmc_core_device->dev.release = intel_pmc_core_release;
> +
> + retval = platform_device_register(pmc_core_device);
> + if (retval)
> + kfree(pmc_core_device);
> +
> + return retval;
> }
>
> static void __exit pmc_core_platform_exit(void)
> {
> - platform_device_unregister(&pmc_core_device);
> + platform_device_unregister(pmc_core_device);
> }
>
> module_init(pmc_core_platform_init);
> --
> 2.28.0
>
