On Tue, Aug 09, 2016 at 07:45:40PM +0200, Noralf Trønnes wrote:
> This adds a way for in-kernel users to iterate over the available
> DRM minors. The implementation is oops safe so the panic code
> can safely use it.
>
> Signed-off-by: Noralf Trønnes <noralf at tronnes.org>
Why iterate over minors? I'd kinda have expected we'd iterate over devices
instead ... And looking ahead, that seems to be what you actually want.
-Daniel
> ---
> drivers/gpu/drm/drm_drv.c | 30 ++++++++++++++++++++++++++++++
> include/drm/drmP.h | 13 +++++++++++++
> 2 files changed, 43 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> index be27ed3..3b14366 100644
> --- a/drivers/gpu/drm/drm_drv.c
> +++ b/drivers/gpu/drm/drm_drv.c
> @@ -292,6 +292,36 @@ void drm_minor_release(struct drm_minor *minor)
> }
>
> /**
> + * drm_minor_lookup - Lookup DRM minor
> + * @minor_id: Minor ID of the DRM-minor
> + *
> + * Looks up the given minor-ID and returns the respective DRM-minor object.
> + * No reference is taken on the underlying device.
> + * See drm_minor_for_each() for iterating over all minors.
> + *
> + * Returns:
> + * Pointer to minor-object or NULL.
> + */
> +struct drm_minor *drm_minor_lookup(unsigned int minor_id)
> +{
> + struct drm_minor *minor;
> + unsigned long flags;
> + int locked = 1;
> +
> + if (oops_in_progress)
> + locked = spin_trylock_irqsave(&drm_minor_lock, flags);
> + else
> + spin_lock_irqsave(&drm_minor_lock, flags);
> +
> + minor = idr_find(&drm_minors_idr, minor_id);
> +
> + if (locked)
> + spin_unlock_irqrestore(&drm_minor_lock, flags);
> +
> + return minor;
> +}
> +
> +/**
> * DOC: driver instance overview
> *
> * A device instance for a drm driver is represented by struct &drm_device.
> This
> diff --git a/include/drm/drmP.h b/include/drm/drmP.h
> index d377865..bc7006e 100644
> --- a/include/drm/drmP.h
> +++ b/include/drm/drmP.h
> @@ -974,6 +974,19 @@ void drm_dev_unregister(struct drm_device *dev);
>
> struct drm_minor *drm_minor_acquire(unsigned int minor_id);
> void drm_minor_release(struct drm_minor *minor);
> +struct drm_minor *drm_minor_lookup(unsigned int minor_id);
> +
> +/**
> + * drm_minor_for_each - Iterate over DRM minors
> + * @minor: DRM minor handle
> + * @type: DRM minor type to iterate over
> + * @id: id handle
> + *
> + * Iterate over the registered DRM minors of a given type.
> + */
> +#define drm_minor_for_each(minor, type, id) \
> + for ((id) = 0; (id) < 64; (id)++) \
> + if (((minor) = drm_minor_lookup((id) + (type) * 64)))
>
> /*@}*/
>
> --
> 2.8.2
>
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--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
