[Intel-gfx] [RFC 2/8] drm/i915: Reference count struct drm_i915_file_private

[Chris Wilson]

Quoting Tvrtko Ursulin (2019-12-19 18:00:13)
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> 
> In the following patches we will develope a need to peek into the client
> owned data from any potential leftover contexts.
> 
> To facilitate this add reference counting to file_priv.
> 
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> ---
>  drivers/gpu/drm/i915/gem/i915_gem_context.c |  2 +-
>  drivers/gpu/drm/i915/i915_drv.c             |  4 ----
>  drivers/gpu/drm/i915/i915_drv.h             |  4 +++-
>  drivers/gpu/drm/i915/i915_gem.c             | 14 +++++++++++++-
>  4 files changed, 17 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> index e5a7c6f02a47..b482b2e5f31f 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> @@ -853,7 +853,7 @@ int i915_gem_context_open(struct drm_i915_private *i915,
>  void i915_gem_context_close(struct drm_file *file)
>  {
>         struct drm_i915_file_private *file_priv = file->driver_priv;
> -       struct drm_i915_private *i915 = file_priv->dev_priv;
> +       struct drm_i915_private *i915 = file_priv->i915;
>         struct i915_gem_context *ctx;
>         unsigned long idx;
>  
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 8b08cfe30151..0c9c93418068 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -1633,13 +1633,9 @@ static void i915_driver_lastclose(struct drm_device *dev)
>  
>  static void i915_driver_postclose(struct drm_device *dev, struct drm_file *file)
>  {
> -       struct drm_i915_file_private *file_priv = file->driver_priv;
> -
>         i915_gem_context_close(file);
>         i915_gem_release(dev, file);
>  
> -       kfree_rcu(file_priv, rcu);

As you are moving the kfree_rcu() into the i915_gem_release (via a put),
I think it also makes sense to move the call for i915_gem_context_close
on this file. Possibly renaming it to i915_gem_file_close() and
s/drm_i915_file_private/i915_gem_file/ or i915_gem_client (with
corresponding name changes) in the process.

For the basic mechanics of this patch though,
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>

(Though I still suggest a bit of playing with i915_gem_context_close,
i915_gem_release to tie them together to the notion of the file better.)
-Chris