[02/51] drm/i915: Don't clear drvdata in ->release
diff mbox series

Message ID 20200323144950.3018436-3-daniel.vetter@ffwll.ch
State New
Headers show
Series
  • drm_device managed resources, v5
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Commit Message

Daniel Vetter March 23, 2020, 2:49 p.m. UTC
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
  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.

Looking at git history this was fixed in the driver core with

commit 0998d0631001288a5974afc0b2a5f568bcdecb4d
Author: Hans de Goede <hdegoede@redhat.com>
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@linuxfoundation.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---
 drivers/gpu/drm/i915/i915_drv.c | 3 ---
 1 file changed, 3 deletions(-)

Comments

Jani Nikula March 25, 2020, 6:20 p.m. UTC | #1
On Mon, 23 Mar 2020, Daniel Vetter <daniel.vetter@ffwll.ch> 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@intel.com>

>
> Looking at git history this was fixed in the driver core with
>
> commit 0998d0631001288a5974afc0b2a5f568bcdecb4d
> Author: Hans de Goede <hdegoede@redhat.com>
> 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@linuxfoundation.org>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> ---
>  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 March 26, 2020, 1:15 p.m. UTC | #2
On Wed, 25 Mar 2020, Jani Nikula <jani.nikula@linux.intel.com> wrote:
> On Mon, 23 Mar 2020, Daniel Vetter <daniel.vetter@ffwll.ch> 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@intel.com>

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@redhat.com>
>> 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@linuxfoundation.org>
>> Cc: Chris Wilson <chris@chris-wilson.co.uk>
>> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
>> ---
>>  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);
>>  }
>>  
>>  /**

Patch
diff mbox series

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);
 }
 
 /**