Messages in this thread | | | Date | Thu, 2 Nov 2017 17:56:32 -0700 | From | Darren Hart <> | Subject | Re: [PATCH] platform/x86: dell-*wmi*: Relay failed initial probe to dependent drivers |
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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@dell.com>
> 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
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