[RFC 5/8] drm/cgroup: Only track clients which are providing drm_cgroup_ops

[Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>]

From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

To reduce the number of tracking going on, especially with drivers which
will not support any sort of control from the drm cgroup controller side,
lets express the funcionality as opt-in and use the presence of
drm_cgroup_ops as activation criteria.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
 kernel/cgroup/drm.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/kernel/cgroup/drm.c b/kernel/cgroup/drm.c
index 68f31797c4f0..60e1f3861576 100644
--- a/kernel/cgroup/drm.c
+++ b/kernel/cgroup/drm.c
@@ -97,6 +97,9 @@ void drmcgroup_client_open(struct drm_file *file_priv)
 {
 	struct drm_cgroup_state *drmcs;
 
+	if (!file_priv->minor->dev->driver->cg_ops)
+		return;
+
 	drmcs = css_to_drmcs(task_get_css(current, drm_cgrp_id));
 
 	mutex_lock(&drmcg_mutex);
@@ -112,6 +115,9 @@ void drmcgroup_client_close(struct drm_file *file_priv)
 
 	drmcs = css_to_drmcs(file_priv->__css);
 
+	if (!file_priv->minor->dev->driver->cg_ops)
+		return;
+
 	mutex_lock(&drmcg_mutex);
 	list_del(&file_priv->clink);
 	file_priv->__css = NULL;
@@ -126,6 +132,9 @@ void drmcgroup_client_migrate(struct drm_file *file_priv)
 	struct drm_cgroup_state *src, *dst;
 	struct cgroup_subsys_state *old;
 
+	if (!file_priv->minor->dev->driver->cg_ops)
+		return;
+
 	mutex_lock(&drmcg_mutex);
 
 	old = file_priv->__css;
-- 
2.39.2