On Wed, 25 Mar 2020, Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx> wrote:
> On Mon, 23 Mar 2020, Daniel Vetter <daniel.vetter@xxxxxxxx> wrote:
>> For two reasons:
>>
>> - The driver core clears this already for us after we're unloaded in
>> __device_release_driver().
>>
>> - It's way too late, the drm_device ->release callback might massively
>> outlive the underlying physical device, since a drm_device can't be
>
> *can be*?
>
>> kept alive by open drm_file or well really anything else userspace
>> is still hanging onto. So if we clear this ourselves, we should
>> clear it in the pci ->remove callback, not in the drm_device
>> ->relase callback.
>
> ->release
>
> Reviewed-by: Jani Nikula <jani.nikula@xxxxxxxxx>
Oops,
drivers/gpu/drm/i915/i915_drv.c: In function ‘i915_driver_destroy’:
drivers/gpu/drm/i915/i915_drv.c:911:18: error: unused variable ‘pdev’ [-Werror=unused-variable]
struct pci_dev *pdev = i915->drm.pdev;
^~~~
>
>>
>> Looking at git history this was fixed in the driver core with
>>
>> commit 0998d0631001288a5974afc0b2a5f568bcdecb4d
>> Author: Hans de Goede <hdegoede@xxxxxxxxxx>
>> Date: Wed May 23 00:09:34 2012 +0200
>>
>> device-core: Ensure drvdata = NULL when no driver is bound
>>
>> v2: Cite the core fix in the commit message (Chris).
>>
>> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
>> Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
>> Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
>> ---
>> drivers/gpu/drm/i915/i915_drv.c | 3 ---
>> 1 file changed, 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
>> index 48ba37e35bea..4792051e9e2e 100644
>> --- a/drivers/gpu/drm/i915/i915_drv.c
>> +++ b/drivers/gpu/drm/i915/i915_drv.c
>> @@ -909,9 +909,6 @@ static void i915_driver_destroy(struct drm_i915_private *i915)
>>
>> drm_dev_fini(&i915->drm);
>> kfree(i915);
>> -
>> - /* And make sure we never chase our dangling pointer from pci_dev */
>> - pci_set_drvdata(pdev, NULL);
>> }
>>
>> /**
--
Jani Nikula, Intel Open Source Graphics Center
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