On Wed, Nov 01, 2017 at 02:28:21PM -0500, Mario Limonciello wrote:
> dell-wmi and dell-smbios-wmi are dependent upon dell-wmi-descriptor
> finishing probe successfully to probe themselves.
>
> Currently if dell-wmi-descriptor fails probing in a non-recoverable way
> (such as invalid header) dell-wmi and dell-smbios-wmi will continue to
> try to redo probing due to deferred probing.
>
> To solve this have the dependent drivers query the dell-wmi-descriptor
> driver whether the descriptor has been determined valid. The possible
> results are:
> -EPROBE_DEFER: Descriptor not yet probed, dependent driver should wait
> and use deferred probing
> < 0: Descriptor probed, invalid. Dependent driver should return an
> error.
> 0: Successful descriptor probe, dependent driver can continue
>
> Successful descriptor probe still doesn't mean that the descriptor driver
> is necessarily bound at the time of initialization of dependent driver.
> Userspace can unbind the driver, so all methods used from driver
> should still be verified to return success values otherwise deferred
> probing be used.
>
> Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxxx>
> diff --git a/drivers/platform/x86/dell-wmi-descriptor.c b/drivers/platform/x86/dell-wmi-descriptor.c
> index 3204c408e261..33c6c7d66f8c 100644
> --- a/drivers/platform/x86/dell-wmi-descriptor.c
> +++ b/drivers/platform/x86/dell-wmi-descriptor.c
> @@ -26,9 +26,16 @@ struct descriptor_priv {
> u32 interface_version;
> u32 size;
> };
> +static int descriptor_valid;
This initializes to 0, which I believe creates an odd race window between when
this init is called and when the first driver calls
dell_wmi_get_descriptor_valid(). Seems like initializing to -EPROBE_DEFER here
in the declaration would be a better right approach.
--
Darren Hart
VMware Open Source Technology Center
