[27/52] drm: Manage drm_mode_config_init with drmm_
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Message ID 20200219102122.1607365-28-daniel.vetter@ffwll.ch
State New
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Series
  • drm_device managed resources
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Commit Message

Daniel Vetter Feb. 19, 2020, 10:20 a.m. UTC
drm_mode_config_cleanup is idempotent, so no harm in calling this
twice. This allows us to gradually switch drivers over by removing
explicit drm_mode_config_cleanup calls.

With this step it's not also possible that (at least for simple
drivers) automatic resource cleanup can be done correctly without a
drm_driver->release hook. Therefore allow this now in
devm_drm_dev_init().

Also with drmm_ explicit drm_driver->release hooks are kinda not the
best option, so deprecate that hook to discourage future users.

v2: Fixup the example in the kerneldoc too.

Cc: "Noralf Trønnes" <noralf@tronnes.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---
 drivers/gpu/drm/drm_drv.c         | 21 +++++----------------
 drivers/gpu/drm/drm_mode_config.c | 12 +++++++++++-
 include/drm/drm_mode_config.h     |  2 +-
 3 files changed, 17 insertions(+), 18 deletions(-)

Comments

Laurent Pinchart Feb. 19, 2020, 1:49 p.m. UTC | #1
Hi Daniel,

Thank you for the patch.

On Wed, Feb 19, 2020 at 11:20:57AM +0100, Daniel Vetter wrote:
> drm_mode_config_cleanup is idempotent, so no harm in calling this
> twice. This allows us to gradually switch drivers over by removing
> explicit drm_mode_config_cleanup calls.
> 
> With this step it's not also possible that (at least for simple
> drivers) automatic resource cleanup can be done correctly without a
> drm_driver->release hook. Therefore allow this now in
> devm_drm_dev_init().
> 
> Also with drmm_ explicit drm_driver->release hooks are kinda not the
> best option, so deprecate that hook to discourage future users.
> 
> v2: Fixup the example in the kerneldoc too.
> 
> Cc: "Noralf Trønnes" <noralf@tronnes.org>
> Cc: Sam Ravnborg <sam@ravnborg.org>
> Cc: Thomas Zimmermann <tzimmermann@suse.de>
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> ---
>  drivers/gpu/drm/drm_drv.c         | 21 +++++----------------
>  drivers/gpu/drm/drm_mode_config.c | 12 +++++++++++-
>  include/drm/drm_mode_config.h     |  2 +-
>  3 files changed, 17 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> index 3cf40864d4a6..428c569aaaf1 100644
> --- a/drivers/gpu/drm/drm_drv.c
> +++ b/drivers/gpu/drm/drm_drv.c
> @@ -267,8 +267,7 @@ void drm_minor_release(struct drm_minor *minor)
>   *
>   * The following example shows a typical structure of a DRM display driver.
>   * The example focus on the probe() function and the other functions that is
> - * almost always present and serves as a demonstration of devm_drm_dev_init()
> - * usage with its accompanying drm_driver->release callback.
> + * almost always present and serves as a demonstration of devm_drm_dev_init().
>   *
>   * .. code-block:: c
>   *
> @@ -278,16 +277,8 @@ void drm_minor_release(struct drm_minor *minor)
>   *		struct clk *pclk;
>   *	};
>   *
> - *	static void driver_drm_release(struct drm_device *drm)
> - *	{
> - *		struct driver_device *priv = container_of(...);
> - *
> - *		drm_mode_config_cleanup(drm);
> - *	}
> - *
>   *	static struct drm_driver driver_drm_driver = {
>   *		[...]
> - *		.release = driver_drm_release,
>   *	};
>   *
>   *	static int driver_probe(struct platform_device *pdev)
> @@ -312,7 +303,9 @@ void drm_minor_release(struct drm_minor *minor)
>   *		}
>   *		drmm_add_final_kfree(drm, priv);
>   *
> - *		drm_mode_config_init(drm);
> + *		ret = drm_mode_config_init(drm);
> + *		if (ret)
> + *			return ret;
>   *
>   *		priv->userspace_facing = drmm_kzalloc(..., GFP_KERNEL);
>   *		if (!priv->userspace_facing)
> @@ -710,8 +703,7 @@ static void devm_drm_dev_init_release(void *data)
>   * @driver: DRM driver
>   *
>   * Managed drm_dev_init(). The DRM device initialized with this function is
> - * automatically put on driver detach using drm_dev_put(). You must supply a
> - * &drm_driver.release callback to control the finalization explicitly.
> + * automatically put on driver detach using drm_dev_put().
>   *
>   * RETURNS:
>   * 0 on success, or error code on failure.
> @@ -722,9 +714,6 @@ int devm_drm_dev_init(struct device *parent,
>  {
>  	int ret;
>  
> -	if (WARN_ON(!driver->release))
> -		return -EINVAL;
> -
>  	ret = drm_dev_init(dev, driver, parent);
>  	if (ret)
>  		return ret;
> diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
> index 08e6eff6a179..957db1edba0c 100644
> --- a/drivers/gpu/drm/drm_mode_config.c
> +++ b/drivers/gpu/drm/drm_mode_config.c
> @@ -25,6 +25,7 @@
>  #include <drm/drm_drv.h>
>  #include <drm/drm_encoder.h>
>  #include <drm/drm_file.h>
> +#include <drm/drm_managed.h>
>  #include <drm/drm_mode_config.h>
>  #include <drm/drm_print.h>
>  #include <linux/dma-resv.h>
> @@ -373,6 +374,11 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
>  	return 0;
>  }
>  
> +static void drm_mode_config_init_release(struct drm_device *dev, void *ptr)
> +{
> +	drm_mode_config_cleanup(dev);
> +}
> +
>  /**
>   * drm_mode_config_init - initialize DRM mode_configuration structure
>   * @dev: DRM device
> @@ -384,8 +390,10 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
>   * problem, since this should happen single threaded at init time. It is the
>   * driver's problem to ensure this guarantee.
>   *
> + * Cleanup is automatically handled through registering drm_mode_config_cleanup
> + * with drmm_add_action().
>   */
> -void drm_mode_config_init(struct drm_device *dev)
> +int drm_mode_config_init(struct drm_device *dev)
>  {
>  	mutex_init(&dev->mode_config.mutex);
>  	drm_modeset_lock_init(&dev->mode_config.connection_mutex);
> @@ -443,6 +451,8 @@ void drm_mode_config_init(struct drm_device *dev)
>  		drm_modeset_acquire_fini(&modeset_ctx);
>  		dma_resv_fini(&resv);
>  	}
> +
> +	return drmm_add_action(dev, drm_mode_config_init_release, NULL);

If this fails, shouldn't drm_mode_config_cleanup() be called here ?

>  }
>  EXPORT_SYMBOL(drm_mode_config_init);
>  
> diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
> index 3bcbe30339f0..160a3e4b51c3 100644
> --- a/include/drm/drm_mode_config.h
> +++ b/include/drm/drm_mode_config.h
> @@ -929,7 +929,7 @@ struct drm_mode_config {
>  	const struct drm_mode_config_helper_funcs *helper_private;
>  };
>  
> -void drm_mode_config_init(struct drm_device *dev);
> +int drm_mode_config_init(struct drm_device *dev);
>  void drm_mode_config_reset(struct drm_device *dev);
>  void drm_mode_config_cleanup(struct drm_device *dev);
>
Daniel Vetter Feb. 19, 2020, 3:47 p.m. UTC | #2
On Wed, Feb 19, 2020 at 2:50 PM Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> Hi Daniel,
>
> Thank you for the patch.
>
> On Wed, Feb 19, 2020 at 11:20:57AM +0100, Daniel Vetter wrote:
> > drm_mode_config_cleanup is idempotent, so no harm in calling this
> > twice. This allows us to gradually switch drivers over by removing
> > explicit drm_mode_config_cleanup calls.
> >
> > With this step it's not also possible that (at least for simple
> > drivers) automatic resource cleanup can be done correctly without a
> > drm_driver->release hook. Therefore allow this now in
> > devm_drm_dev_init().
> >
> > Also with drmm_ explicit drm_driver->release hooks are kinda not the
> > best option, so deprecate that hook to discourage future users.
> >
> > v2: Fixup the example in the kerneldoc too.
> >
> > Cc: "Noralf Trønnes" <noralf@tronnes.org>
> > Cc: Sam Ravnborg <sam@ravnborg.org>
> > Cc: Thomas Zimmermann <tzimmermann@suse.de>
> > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> > ---
> >  drivers/gpu/drm/drm_drv.c         | 21 +++++----------------
> >  drivers/gpu/drm/drm_mode_config.c | 12 +++++++++++-
> >  include/drm/drm_mode_config.h     |  2 +-
> >  3 files changed, 17 insertions(+), 18 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> > index 3cf40864d4a6..428c569aaaf1 100644
> > --- a/drivers/gpu/drm/drm_drv.c
> > +++ b/drivers/gpu/drm/drm_drv.c
> > @@ -267,8 +267,7 @@ void drm_minor_release(struct drm_minor *minor)
> >   *
> >   * The following example shows a typical structure of a DRM display driver.
> >   * The example focus on the probe() function and the other functions that is
> > - * almost always present and serves as a demonstration of devm_drm_dev_init()
> > - * usage with its accompanying drm_driver->release callback.
> > + * almost always present and serves as a demonstration of devm_drm_dev_init().
> >   *
> >   * .. code-block:: c
> >   *
> > @@ -278,16 +277,8 @@ void drm_minor_release(struct drm_minor *minor)
> >   *           struct clk *pclk;
> >   *   };
> >   *
> > - *   static void driver_drm_release(struct drm_device *drm)
> > - *   {
> > - *           struct driver_device *priv = container_of(...);
> > - *
> > - *           drm_mode_config_cleanup(drm);
> > - *   }
> > - *
> >   *   static struct drm_driver driver_drm_driver = {
> >   *           [...]
> > - *           .release = driver_drm_release,
> >   *   };
> >   *
> >   *   static int driver_probe(struct platform_device *pdev)
> > @@ -312,7 +303,9 @@ void drm_minor_release(struct drm_minor *minor)
> >   *           }
> >   *           drmm_add_final_kfree(drm, priv);
> >   *
> > - *           drm_mode_config_init(drm);
> > + *           ret = drm_mode_config_init(drm);
> > + *           if (ret)
> > + *                   return ret;
> >   *
> >   *           priv->userspace_facing = drmm_kzalloc(..., GFP_KERNEL);
> >   *           if (!priv->userspace_facing)
> > @@ -710,8 +703,7 @@ static void devm_drm_dev_init_release(void *data)
> >   * @driver: DRM driver
> >   *
> >   * Managed drm_dev_init(). The DRM device initialized with this function is
> > - * automatically put on driver detach using drm_dev_put(). You must supply a
> > - * &drm_driver.release callback to control the finalization explicitly.
> > + * automatically put on driver detach using drm_dev_put().
> >   *
> >   * RETURNS:
> >   * 0 on success, or error code on failure.
> > @@ -722,9 +714,6 @@ int devm_drm_dev_init(struct device *parent,
> >  {
> >       int ret;
> >
> > -     if (WARN_ON(!driver->release))
> > -             return -EINVAL;
> > -
> >       ret = drm_dev_init(dev, driver, parent);
> >       if (ret)
> >               return ret;
> > diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
> > index 08e6eff6a179..957db1edba0c 100644
> > --- a/drivers/gpu/drm/drm_mode_config.c
> > +++ b/drivers/gpu/drm/drm_mode_config.c
> > @@ -25,6 +25,7 @@
> >  #include <drm/drm_drv.h>
> >  #include <drm/drm_encoder.h>
> >  #include <drm/drm_file.h>
> > +#include <drm/drm_managed.h>
> >  #include <drm/drm_mode_config.h>
> >  #include <drm/drm_print.h>
> >  #include <linux/dma-resv.h>
> > @@ -373,6 +374,11 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
> >       return 0;
> >  }
> >
> > +static void drm_mode_config_init_release(struct drm_device *dev, void *ptr)
> > +{
> > +     drm_mode_config_cleanup(dev);
> > +}
> > +
> >  /**
> >   * drm_mode_config_init - initialize DRM mode_configuration structure
> >   * @dev: DRM device
> > @@ -384,8 +390,10 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
> >   * problem, since this should happen single threaded at init time. It is the
> >   * driver's problem to ensure this guarantee.
> >   *
> > + * Cleanup is automatically handled through registering drm_mode_config_cleanup
> > + * with drmm_add_action().
> >   */
> > -void drm_mode_config_init(struct drm_device *dev)
> > +int drm_mode_config_init(struct drm_device *dev)
> >  {
> >       mutex_init(&dev->mode_config.mutex);
> >       drm_modeset_lock_init(&dev->mode_config.connection_mutex);
> > @@ -443,6 +451,8 @@ void drm_mode_config_init(struct drm_device *dev)
> >               drm_modeset_acquire_fini(&modeset_ctx);
> >               dma_resv_fini(&resv);
> >       }
> > +
> > +     return drmm_add_action(dev, drm_mode_config_init_release, NULL);
>
> If this fails, shouldn't drm_mode_config_cleanup() be called here ?

Maybe for ocd reasons, but not for actually cleaning up anything. It's
just a bunch of empty lists that drm_mode_config_cleanup will walk and
do nothing about. Not sure I should add that ...
-Daniel

> >  }
> >  EXPORT_SYMBOL(drm_mode_config_init);
> >
> > diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
> > index 3bcbe30339f0..160a3e4b51c3 100644
> > --- a/include/drm/drm_mode_config.h
> > +++ b/include/drm/drm_mode_config.h
> > @@ -929,7 +929,7 @@ struct drm_mode_config {
> >       const struct drm_mode_config_helper_funcs *helper_private;
> >  };
> >
> > -void drm_mode_config_init(struct drm_device *dev);
> > +int drm_mode_config_init(struct drm_device *dev);
> >  void drm_mode_config_reset(struct drm_device *dev);
> >  void drm_mode_config_cleanup(struct drm_device *dev);
> >
>
> --
> Regards,
>
> Laurent Pinchart
Laurent Pinchart Feb. 19, 2020, 4:07 p.m. UTC | #3
Hi Daniel,

On Wed, Feb 19, 2020 at 04:47:55PM +0100, Daniel Vetter wrote:
> On Wed, Feb 19, 2020 at 2:50 PM Laurent Pinchart wrote:
> > On Wed, Feb 19, 2020 at 11:20:57AM +0100, Daniel Vetter wrote:
> > > drm_mode_config_cleanup is idempotent, so no harm in calling this
> > > twice. This allows us to gradually switch drivers over by removing
> > > explicit drm_mode_config_cleanup calls.
> > >
> > > With this step it's not also possible that (at least for simple
> > > drivers) automatic resource cleanup can be done correctly without a
> > > drm_driver->release hook. Therefore allow this now in
> > > devm_drm_dev_init().
> > >
> > > Also with drmm_ explicit drm_driver->release hooks are kinda not the
> > > best option, so deprecate that hook to discourage future users.
> > >
> > > v2: Fixup the example in the kerneldoc too.
> > >
> > > Cc: "Noralf Trønnes" <noralf@tronnes.org>
> > > Cc: Sam Ravnborg <sam@ravnborg.org>
> > > Cc: Thomas Zimmermann <tzimmermann@suse.de>
> > > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> > > ---
> > >  drivers/gpu/drm/drm_drv.c         | 21 +++++----------------
> > >  drivers/gpu/drm/drm_mode_config.c | 12 +++++++++++-
> > >  include/drm/drm_mode_config.h     |  2 +-
> > >  3 files changed, 17 insertions(+), 18 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> > > index 3cf40864d4a6..428c569aaaf1 100644
> > > --- a/drivers/gpu/drm/drm_drv.c
> > > +++ b/drivers/gpu/drm/drm_drv.c
> > > @@ -267,8 +267,7 @@ void drm_minor_release(struct drm_minor *minor)
> > >   *
> > >   * The following example shows a typical structure of a DRM display driver.
> > >   * The example focus on the probe() function and the other functions that is
> > > - * almost always present and serves as a demonstration of devm_drm_dev_init()
> > > - * usage with its accompanying drm_driver->release callback.
> > > + * almost always present and serves as a demonstration of devm_drm_dev_init().
> > >   *
> > >   * .. code-block:: c
> > >   *
> > > @@ -278,16 +277,8 @@ void drm_minor_release(struct drm_minor *minor)
> > >   *           struct clk *pclk;
> > >   *   };
> > >   *
> > > - *   static void driver_drm_release(struct drm_device *drm)
> > > - *   {
> > > - *           struct driver_device *priv = container_of(...);
> > > - *
> > > - *           drm_mode_config_cleanup(drm);
> > > - *   }
> > > - *
> > >   *   static struct drm_driver driver_drm_driver = {
> > >   *           [...]
> > > - *           .release = driver_drm_release,
> > >   *   };
> > >   *
> > >   *   static int driver_probe(struct platform_device *pdev)
> > > @@ -312,7 +303,9 @@ void drm_minor_release(struct drm_minor *minor)
> > >   *           }
> > >   *           drmm_add_final_kfree(drm, priv);
> > >   *
> > > - *           drm_mode_config_init(drm);
> > > + *           ret = drm_mode_config_init(drm);
> > > + *           if (ret)
> > > + *                   return ret;
> > >   *
> > >   *           priv->userspace_facing = drmm_kzalloc(..., GFP_KERNEL);
> > >   *           if (!priv->userspace_facing)
> > > @@ -710,8 +703,7 @@ static void devm_drm_dev_init_release(void *data)
> > >   * @driver: DRM driver
> > >   *
> > >   * Managed drm_dev_init(). The DRM device initialized with this function is
> > > - * automatically put on driver detach using drm_dev_put(). You must supply a
> > > - * &drm_driver.release callback to control the finalization explicitly.
> > > + * automatically put on driver detach using drm_dev_put().
> > >   *
> > >   * RETURNS:
> > >   * 0 on success, or error code on failure.
> > > @@ -722,9 +714,6 @@ int devm_drm_dev_init(struct device *parent,
> > >  {
> > >       int ret;
> > >
> > > -     if (WARN_ON(!driver->release))
> > > -             return -EINVAL;
> > > -
> > >       ret = drm_dev_init(dev, driver, parent);
> > >       if (ret)
> > >               return ret;
> > > diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
> > > index 08e6eff6a179..957db1edba0c 100644
> > > --- a/drivers/gpu/drm/drm_mode_config.c
> > > +++ b/drivers/gpu/drm/drm_mode_config.c
> > > @@ -25,6 +25,7 @@
> > >  #include <drm/drm_drv.h>
> > >  #include <drm/drm_encoder.h>
> > >  #include <drm/drm_file.h>
> > > +#include <drm/drm_managed.h>
> > >  #include <drm/drm_mode_config.h>
> > >  #include <drm/drm_print.h>
> > >  #include <linux/dma-resv.h>
> > > @@ -373,6 +374,11 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
> > >       return 0;
> > >  }
> > >
> > > +static void drm_mode_config_init_release(struct drm_device *dev, void *ptr)
> > > +{
> > > +     drm_mode_config_cleanup(dev);
> > > +}
> > > +
> > >  /**
> > >   * drm_mode_config_init - initialize DRM mode_configuration structure
> > >   * @dev: DRM device
> > > @@ -384,8 +390,10 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
> > >   * problem, since this should happen single threaded at init time. It is the
> > >   * driver's problem to ensure this guarantee.
> > >   *
> > > + * Cleanup is automatically handled through registering drm_mode_config_cleanup
> > > + * with drmm_add_action().
> > >   */
> > > -void drm_mode_config_init(struct drm_device *dev)
> > > +int drm_mode_config_init(struct drm_device *dev)
> > >  {
> > >       mutex_init(&dev->mode_config.mutex);
> > >       drm_modeset_lock_init(&dev->mode_config.connection_mutex);
> > > @@ -443,6 +451,8 @@ void drm_mode_config_init(struct drm_device *dev)
> > >               drm_modeset_acquire_fini(&modeset_ctx);
> > >               dma_resv_fini(&resv);
> > >       }
> > > +
> > > +     return drmm_add_action(dev, drm_mode_config_init_release, NULL);
> >
> > If this fails, shouldn't drm_mode_config_cleanup() be called here ?
> 
> Maybe for ocd reasons, but not for actually cleaning up anything. It's
> just a bunch of empty lists that drm_mode_config_cleanup will walk and
> do nothing about. Not sure I should add that ...

How about the ida init, and the mutex_init() that isn't a no-op when
lock debugging is enabled ?

> > >  }
> > >  EXPORT_SYMBOL(drm_mode_config_init);
> > >
> > > diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
> > > index 3bcbe30339f0..160a3e4b51c3 100644
> > > --- a/include/drm/drm_mode_config.h
> > > +++ b/include/drm/drm_mode_config.h
> > > @@ -929,7 +929,7 @@ struct drm_mode_config {
> > >       const struct drm_mode_config_helper_funcs *helper_private;
> > >  };
> > >
> > > -void drm_mode_config_init(struct drm_device *dev);
> > > +int drm_mode_config_init(struct drm_device *dev);
> > >  void drm_mode_config_reset(struct drm_device *dev);
> > >  void drm_mode_config_cleanup(struct drm_device *dev);
> > >
Daniel Vetter Feb. 19, 2020, 4:23 p.m. UTC | #4
On Wed, Feb 19, 2020 at 5:08 PM Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> Hi Daniel,
>
> On Wed, Feb 19, 2020 at 04:47:55PM +0100, Daniel Vetter wrote:
> > On Wed, Feb 19, 2020 at 2:50 PM Laurent Pinchart wrote:
> > > On Wed, Feb 19, 2020 at 11:20:57AM +0100, Daniel Vetter wrote:
> > > > drm_mode_config_cleanup is idempotent, so no harm in calling this
> > > > twice. This allows us to gradually switch drivers over by removing
> > > > explicit drm_mode_config_cleanup calls.
> > > >
> > > > With this step it's not also possible that (at least for simple
> > > > drivers) automatic resource cleanup can be done correctly without a
> > > > drm_driver->release hook. Therefore allow this now in
> > > > devm_drm_dev_init().
> > > >
> > > > Also with drmm_ explicit drm_driver->release hooks are kinda not the
> > > > best option, so deprecate that hook to discourage future users.
> > > >
> > > > v2: Fixup the example in the kerneldoc too.
> > > >
> > > > Cc: "Noralf Trønnes" <noralf@tronnes.org>
> > > > Cc: Sam Ravnborg <sam@ravnborg.org>
> > > > Cc: Thomas Zimmermann <tzimmermann@suse.de>
> > > > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> > > > ---
> > > >  drivers/gpu/drm/drm_drv.c         | 21 +++++----------------
> > > >  drivers/gpu/drm/drm_mode_config.c | 12 +++++++++++-
> > > >  include/drm/drm_mode_config.h     |  2 +-
> > > >  3 files changed, 17 insertions(+), 18 deletions(-)
> > > >
> > > > diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> > > > index 3cf40864d4a6..428c569aaaf1 100644
> > > > --- a/drivers/gpu/drm/drm_drv.c
> > > > +++ b/drivers/gpu/drm/drm_drv.c
> > > > @@ -267,8 +267,7 @@ void drm_minor_release(struct drm_minor *minor)
> > > >   *
> > > >   * The following example shows a typical structure of a DRM display driver.
> > > >   * The example focus on the probe() function and the other functions that is
> > > > - * almost always present and serves as a demonstration of devm_drm_dev_init()
> > > > - * usage with its accompanying drm_driver->release callback.
> > > > + * almost always present and serves as a demonstration of devm_drm_dev_init().
> > > >   *
> > > >   * .. code-block:: c
> > > >   *
> > > > @@ -278,16 +277,8 @@ void drm_minor_release(struct drm_minor *minor)
> > > >   *           struct clk *pclk;
> > > >   *   };
> > > >   *
> > > > - *   static void driver_drm_release(struct drm_device *drm)
> > > > - *   {
> > > > - *           struct driver_device *priv = container_of(...);
> > > > - *
> > > > - *           drm_mode_config_cleanup(drm);
> > > > - *   }
> > > > - *
> > > >   *   static struct drm_driver driver_drm_driver = {
> > > >   *           [...]
> > > > - *           .release = driver_drm_release,
> > > >   *   };
> > > >   *
> > > >   *   static int driver_probe(struct platform_device *pdev)
> > > > @@ -312,7 +303,9 @@ void drm_minor_release(struct drm_minor *minor)
> > > >   *           }
> > > >   *           drmm_add_final_kfree(drm, priv);
> > > >   *
> > > > - *           drm_mode_config_init(drm);
> > > > + *           ret = drm_mode_config_init(drm);
> > > > + *           if (ret)
> > > > + *                   return ret;
> > > >   *
> > > >   *           priv->userspace_facing = drmm_kzalloc(..., GFP_KERNEL);
> > > >   *           if (!priv->userspace_facing)
> > > > @@ -710,8 +703,7 @@ static void devm_drm_dev_init_release(void *data)
> > > >   * @driver: DRM driver
> > > >   *
> > > >   * Managed drm_dev_init(). The DRM device initialized with this function is
> > > > - * automatically put on driver detach using drm_dev_put(). You must supply a
> > > > - * &drm_driver.release callback to control the finalization explicitly.
> > > > + * automatically put on driver detach using drm_dev_put().
> > > >   *
> > > >   * RETURNS:
> > > >   * 0 on success, or error code on failure.
> > > > @@ -722,9 +714,6 @@ int devm_drm_dev_init(struct device *parent,
> > > >  {
> > > >       int ret;
> > > >
> > > > -     if (WARN_ON(!driver->release))
> > > > -             return -EINVAL;
> > > > -
> > > >       ret = drm_dev_init(dev, driver, parent);
> > > >       if (ret)
> > > >               return ret;
> > > > diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
> > > > index 08e6eff6a179..957db1edba0c 100644
> > > > --- a/drivers/gpu/drm/drm_mode_config.c
> > > > +++ b/drivers/gpu/drm/drm_mode_config.c
> > > > @@ -25,6 +25,7 @@
> > > >  #include <drm/drm_drv.h>
> > > >  #include <drm/drm_encoder.h>
> > > >  #include <drm/drm_file.h>
> > > > +#include <drm/drm_managed.h>
> > > >  #include <drm/drm_mode_config.h>
> > > >  #include <drm/drm_print.h>
> > > >  #include <linux/dma-resv.h>
> > > > @@ -373,6 +374,11 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
> > > >       return 0;
> > > >  }
> > > >
> > > > +static void drm_mode_config_init_release(struct drm_device *dev, void *ptr)
> > > > +{
> > > > +     drm_mode_config_cleanup(dev);
> > > > +}
> > > > +
> > > >  /**
> > > >   * drm_mode_config_init - initialize DRM mode_configuration structure
> > > >   * @dev: DRM device
> > > > @@ -384,8 +390,10 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
> > > >   * problem, since this should happen single threaded at init time. It is the
> > > >   * driver's problem to ensure this guarantee.
> > > >   *
> > > > + * Cleanup is automatically handled through registering drm_mode_config_cleanup
> > > > + * with drmm_add_action().
> > > >   */
> > > > -void drm_mode_config_init(struct drm_device *dev)
> > > > +int drm_mode_config_init(struct drm_device *dev)
> > > >  {
> > > >       mutex_init(&dev->mode_config.mutex);
> > > >       drm_modeset_lock_init(&dev->mode_config.connection_mutex);
> > > > @@ -443,6 +451,8 @@ void drm_mode_config_init(struct drm_device *dev)
> > > >               drm_modeset_acquire_fini(&modeset_ctx);
> > > >               dma_resv_fini(&resv);
> > > >       }
> > > > +
> > > > +     return drmm_add_action(dev, drm_mode_config_init_release, NULL);
> > >
> > > If this fails, shouldn't drm_mode_config_cleanup() be called here ?
> >
> > Maybe for ocd reasons, but not for actually cleaning up anything. It's
> > just a bunch of empty lists that drm_mode_config_cleanup will walk and
> > do nothing about. Not sure I should add that ...
>
> How about the ida init, and the mutex_init() that isn't a no-op when
> lock debugging is enabled ?

Hm right, I'll fix this.

Fun thing is that I've found a pile of missing mutex_destroy and
ida_cleanup() while reviewing all the code I've read. Not sure I've
fixed them all up ...
-Daniel

>
> > > >  }
> > > >  EXPORT_SYMBOL(drm_mode_config_init);
> > > >
> > > > diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
> > > > index 3bcbe30339f0..160a3e4b51c3 100644
> > > > --- a/include/drm/drm_mode_config.h
> > > > +++ b/include/drm/drm_mode_config.h
> > > > @@ -929,7 +929,7 @@ struct drm_mode_config {
> > > >       const struct drm_mode_config_helper_funcs *helper_private;
> > > >  };
> > > >
> > > > -void drm_mode_config_init(struct drm_device *dev);
> > > > +int drm_mode_config_init(struct drm_device *dev);
> > > >  void drm_mode_config_reset(struct drm_device *dev);
> > > >  void drm_mode_config_cleanup(struct drm_device *dev);
> > > >
>
> --
> Regards,
>
> Laurent Pinchart
Noralf Trønnes Feb. 19, 2020, 5:30 p.m. UTC | #5
Den 19.02.2020 17.23, skrev Daniel Vetter:
> On Wed, Feb 19, 2020 at 5:08 PM Laurent Pinchart
> <laurent.pinchart@ideasonboard.com> wrote:
>>
>> Hi Daniel,
>>
>> On Wed, Feb 19, 2020 at 04:47:55PM +0100, Daniel Vetter wrote:
>>> On Wed, Feb 19, 2020 at 2:50 PM Laurent Pinchart wrote:
>>>> On Wed, Feb 19, 2020 at 11:20:57AM +0100, Daniel Vetter wrote:
>>>>> drm_mode_config_cleanup is idempotent, so no harm in calling this
>>>>> twice. This allows us to gradually switch drivers over by removing
>>>>> explicit drm_mode_config_cleanup calls.
>>>>>
>>>>> With this step it's not also possible that (at least for simple
>>>>> drivers) automatic resource cleanup can be done correctly without a
>>>>> drm_driver->release hook. Therefore allow this now in
>>>>> devm_drm_dev_init().
>>>>>
>>>>> Also with drmm_ explicit drm_driver->release hooks are kinda not the
>>>>> best option, so deprecate that hook to discourage future users.
>>>>>
>>>>> v2: Fixup the example in the kerneldoc too.
>>>>>
>>>>> Cc: "Noralf Trønnes" <noralf@tronnes.org>
>>>>> Cc: Sam Ravnborg <sam@ravnborg.org>
>>>>> Cc: Thomas Zimmermann <tzimmermann@suse.de>
>>>>> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
>>>>> ---

<snip>

>>>>> diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
>>>>> index 08e6eff6a179..957db1edba0c 100644
>>>>> --- a/drivers/gpu/drm/drm_mode_config.c
>>>>> +++ b/drivers/gpu/drm/drm_mode_config.c
>>>>> @@ -25,6 +25,7 @@
>>>>>  #include <drm/drm_drv.h>
>>>>>  #include <drm/drm_encoder.h>
>>>>>  #include <drm/drm_file.h>
>>>>> +#include <drm/drm_managed.h>
>>>>>  #include <drm/drm_mode_config.h>
>>>>>  #include <drm/drm_print.h>
>>>>>  #include <linux/dma-resv.h>
>>>>> @@ -373,6 +374,11 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
>>>>>       return 0;
>>>>>  }
>>>>>
>>>>> +static void drm_mode_config_init_release(struct drm_device *dev, void *ptr)
>>>>> +{
>>>>> +     drm_mode_config_cleanup(dev);
>>>>> +}
>>>>> +
>>>>>  /**
>>>>>   * drm_mode_config_init - initialize DRM mode_configuration structure
>>>>>   * @dev: DRM device
>>>>> @@ -384,8 +390,10 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
>>>>>   * problem, since this should happen single threaded at init time. It is the
>>>>>   * driver's problem to ensure this guarantee.
>>>>>   *
>>>>> + * Cleanup is automatically handled through registering drm_mode_config_cleanup
>>>>> + * with drmm_add_action().
>>>>>   */
>>>>> -void drm_mode_config_init(struct drm_device *dev)
>>>>> +int drm_mode_config_init(struct drm_device *dev)
>>>>>  {
>>>>>       mutex_init(&dev->mode_config.mutex);
>>>>>       drm_modeset_lock_init(&dev->mode_config.connection_mutex);
>>>>> @@ -443,6 +451,8 @@ void drm_mode_config_init(struct drm_device *dev)
>>>>>               drm_modeset_acquire_fini(&modeset_ctx);
>>>>>               dma_resv_fini(&resv);
>>>>>       }
>>>>> +
>>>>> +     return drmm_add_action(dev, drm_mode_config_init_release, NULL);
>>>>
>>>> If this fails, shouldn't drm_mode_config_cleanup() be called here ?
>>>
>>> Maybe for ocd reasons, but not for actually cleaning up anything. It's
>>> just a bunch of empty lists that drm_mode_config_cleanup will walk and
>>> do nothing about. Not sure I should add that ...
>>
>> How about the ida init, and the mutex_init() that isn't a no-op when
>> lock debugging is enabled ?
> 
> Hm right, I'll fix this.
> 

You could make a drmm_ version of devm_add_action_or_reset() for this.

Noralf.

> Fun thing is that I've found a pile of missing mutex_destroy and
> ida_cleanup() while reviewing all the code I've read. Not sure I've
> fixed them all up ...
> -Daniel
> 
>>
>>>>>  }
>>>>>  EXPORT_SYMBOL(drm_mode_config_init);
>>>>>
Daniel Vetter Feb. 19, 2020, 6:12 p.m. UTC | #6
On Wed, Feb 19, 2020 at 6:30 PM Noralf Trønnes <noralf@tronnes.org> wrote:
>
>
>
> Den 19.02.2020 17.23, skrev Daniel Vetter:
> > On Wed, Feb 19, 2020 at 5:08 PM Laurent Pinchart
> > <laurent.pinchart@ideasonboard.com> wrote:
> >>
> >> Hi Daniel,
> >>
> >> On Wed, Feb 19, 2020 at 04:47:55PM +0100, Daniel Vetter wrote:
> >>> On Wed, Feb 19, 2020 at 2:50 PM Laurent Pinchart wrote:
> >>>> On Wed, Feb 19, 2020 at 11:20:57AM +0100, Daniel Vetter wrote:
> >>>>> drm_mode_config_cleanup is idempotent, so no harm in calling this
> >>>>> twice. This allows us to gradually switch drivers over by removing
> >>>>> explicit drm_mode_config_cleanup calls.
> >>>>>
> >>>>> With this step it's not also possible that (at least for simple
> >>>>> drivers) automatic resource cleanup can be done correctly without a
> >>>>> drm_driver->release hook. Therefore allow this now in
> >>>>> devm_drm_dev_init().
> >>>>>
> >>>>> Also with drmm_ explicit drm_driver->release hooks are kinda not the
> >>>>> best option, so deprecate that hook to discourage future users.
> >>>>>
> >>>>> v2: Fixup the example in the kerneldoc too.
> >>>>>
> >>>>> Cc: "Noralf Trønnes" <noralf@tronnes.org>
> >>>>> Cc: Sam Ravnborg <sam@ravnborg.org>
> >>>>> Cc: Thomas Zimmermann <tzimmermann@suse.de>
> >>>>> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> >>>>> ---
>
> <snip>
>
> >>>>> diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
> >>>>> index 08e6eff6a179..957db1edba0c 100644
> >>>>> --- a/drivers/gpu/drm/drm_mode_config.c
> >>>>> +++ b/drivers/gpu/drm/drm_mode_config.c
> >>>>> @@ -25,6 +25,7 @@
> >>>>>  #include <drm/drm_drv.h>
> >>>>>  #include <drm/drm_encoder.h>
> >>>>>  #include <drm/drm_file.h>
> >>>>> +#include <drm/drm_managed.h>
> >>>>>  #include <drm/drm_mode_config.h>
> >>>>>  #include <drm/drm_print.h>
> >>>>>  #include <linux/dma-resv.h>
> >>>>> @@ -373,6 +374,11 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
> >>>>>       return 0;
> >>>>>  }
> >>>>>
> >>>>> +static void drm_mode_config_init_release(struct drm_device *dev, void *ptr)
> >>>>> +{
> >>>>> +     drm_mode_config_cleanup(dev);
> >>>>> +}
> >>>>> +
> >>>>>  /**
> >>>>>   * drm_mode_config_init - initialize DRM mode_configuration structure
> >>>>>   * @dev: DRM device
> >>>>> @@ -384,8 +390,10 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
> >>>>>   * problem, since this should happen single threaded at init time. It is the
> >>>>>   * driver's problem to ensure this guarantee.
> >>>>>   *
> >>>>> + * Cleanup is automatically handled through registering drm_mode_config_cleanup
> >>>>> + * with drmm_add_action().
> >>>>>   */
> >>>>> -void drm_mode_config_init(struct drm_device *dev)
> >>>>> +int drm_mode_config_init(struct drm_device *dev)
> >>>>>  {
> >>>>>       mutex_init(&dev->mode_config.mutex);
> >>>>>       drm_modeset_lock_init(&dev->mode_config.connection_mutex);
> >>>>> @@ -443,6 +451,8 @@ void drm_mode_config_init(struct drm_device *dev)
> >>>>>               drm_modeset_acquire_fini(&modeset_ctx);
> >>>>>               dma_resv_fini(&resv);
> >>>>>       }
> >>>>> +
> >>>>> +     return drmm_add_action(dev, drm_mode_config_init_release, NULL);
> >>>>
> >>>> If this fails, shouldn't drm_mode_config_cleanup() be called here ?
> >>>
> >>> Maybe for ocd reasons, but not for actually cleaning up anything. It's
> >>> just a bunch of empty lists that drm_mode_config_cleanup will walk and
> >>> do nothing about. Not sure I should add that ...
> >>
> >> How about the ida init, and the mutex_init() that isn't a no-op when
> >> lock debugging is enabled ?
> >
> > Hm right, I'll fix this.
> >
>
> You could make a drmm_ version of devm_add_action_or_reset() for this.

...

How did I not see that in devres.c. In my defense, I've never written
a driver using devm because of all the lifetime bugs that would cause
in drm, but yes this is exactly what we want here.

Thanks a lot for the pointer, I'll go do some typing!

Cheers, Daniel

Patch
diff mbox series

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 3cf40864d4a6..428c569aaaf1 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -267,8 +267,7 @@  void drm_minor_release(struct drm_minor *minor)
  *
  * The following example shows a typical structure of a DRM display driver.
  * The example focus on the probe() function and the other functions that is
- * almost always present and serves as a demonstration of devm_drm_dev_init()
- * usage with its accompanying drm_driver->release callback.
+ * almost always present and serves as a demonstration of devm_drm_dev_init().
  *
  * .. code-block:: c
  *
@@ -278,16 +277,8 @@  void drm_minor_release(struct drm_minor *minor)
  *		struct clk *pclk;
  *	};
  *
- *	static void driver_drm_release(struct drm_device *drm)
- *	{
- *		struct driver_device *priv = container_of(...);
- *
- *		drm_mode_config_cleanup(drm);
- *	}
- *
  *	static struct drm_driver driver_drm_driver = {
  *		[...]
- *		.release = driver_drm_release,
  *	};
  *
  *	static int driver_probe(struct platform_device *pdev)
@@ -312,7 +303,9 @@  void drm_minor_release(struct drm_minor *minor)
  *		}
  *		drmm_add_final_kfree(drm, priv);
  *
- *		drm_mode_config_init(drm);
+ *		ret = drm_mode_config_init(drm);
+ *		if (ret)
+ *			return ret;
  *
  *		priv->userspace_facing = drmm_kzalloc(..., GFP_KERNEL);
  *		if (!priv->userspace_facing)
@@ -710,8 +703,7 @@  static void devm_drm_dev_init_release(void *data)
  * @driver: DRM driver
  *
  * Managed drm_dev_init(). The DRM device initialized with this function is
- * automatically put on driver detach using drm_dev_put(). You must supply a
- * &drm_driver.release callback to control the finalization explicitly.
+ * automatically put on driver detach using drm_dev_put().
  *
  * RETURNS:
  * 0 on success, or error code on failure.
@@ -722,9 +714,6 @@  int devm_drm_dev_init(struct device *parent,
 {
 	int ret;
 
-	if (WARN_ON(!driver->release))
-		return -EINVAL;
-
 	ret = drm_dev_init(dev, driver, parent);
 	if (ret)
 		return ret;
diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
index 08e6eff6a179..957db1edba0c 100644
--- a/drivers/gpu/drm/drm_mode_config.c
+++ b/drivers/gpu/drm/drm_mode_config.c
@@ -25,6 +25,7 @@ 
 #include <drm/drm_drv.h>
 #include <drm/drm_encoder.h>
 #include <drm/drm_file.h>
+#include <drm/drm_managed.h>
 #include <drm/drm_mode_config.h>
 #include <drm/drm_print.h>
 #include <linux/dma-resv.h>
@@ -373,6 +374,11 @@  static int drm_mode_create_standard_properties(struct drm_device *dev)
 	return 0;
 }
 
+static void drm_mode_config_init_release(struct drm_device *dev, void *ptr)
+{
+	drm_mode_config_cleanup(dev);
+}
+
 /**
  * drm_mode_config_init - initialize DRM mode_configuration structure
  * @dev: DRM device
@@ -384,8 +390,10 @@  static int drm_mode_create_standard_properties(struct drm_device *dev)
  * problem, since this should happen single threaded at init time. It is the
  * driver's problem to ensure this guarantee.
  *
+ * Cleanup is automatically handled through registering drm_mode_config_cleanup
+ * with drmm_add_action().
  */
-void drm_mode_config_init(struct drm_device *dev)
+int drm_mode_config_init(struct drm_device *dev)
 {
 	mutex_init(&dev->mode_config.mutex);
 	drm_modeset_lock_init(&dev->mode_config.connection_mutex);
@@ -443,6 +451,8 @@  void drm_mode_config_init(struct drm_device *dev)
 		drm_modeset_acquire_fini(&modeset_ctx);
 		dma_resv_fini(&resv);
 	}
+
+	return drmm_add_action(dev, drm_mode_config_init_release, NULL);
 }
 EXPORT_SYMBOL(drm_mode_config_init);
 
diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
index 3bcbe30339f0..160a3e4b51c3 100644
--- a/include/drm/drm_mode_config.h
+++ b/include/drm/drm_mode_config.h
@@ -929,7 +929,7 @@  struct drm_mode_config {
 	const struct drm_mode_config_helper_funcs *helper_private;
 };
 
-void drm_mode_config_init(struct drm_device *dev);
+int drm_mode_config_init(struct drm_device *dev);
 void drm_mode_config_reset(struct drm_device *dev);
 void drm_mode_config_cleanup(struct drm_device *dev);