[PATCH RFC 1/5] cgroup: Introduce cgroup for drm subsystem

[Kenny Ho]

Change-Id: I6830d3990f63f0c13abeba29b1d330cf28882831
Signed-off-by: Kenny Ho <Kenny.Ho at amd.com>
---
 include/linux/cgroup_drm.h    | 32 ++++++++++++++++++++++++
 include/linux/cgroup_subsys.h |  4 +++
 init/Kconfig                  |  5 ++++
 kernel/cgroup/Makefile        |  1 +
 kernel/cgroup/drm.c           | 46 +++++++++++++++++++++++++++++++++++
 5 files changed, 88 insertions(+)
 create mode 100644 include/linux/cgroup_drm.h
 create mode 100644 kernel/cgroup/drm.c

diff --git a/include/linux/cgroup_drm.h b/include/linux/cgroup_drm.h
new file mode 100644
index 000000000000..79ab38b0f46d
--- /dev/null
+++ b/include/linux/cgroup_drm.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: MIT
+ * Copyright 2018 Advanced Micro Devices, Inc.
+ */
+#ifndef _CGROUP_DRM_H
+#define _CGROUP_DRM_H
+
+#ifdef CONFIG_CGROUP_DRM
+
+#include <linux/cgroup.h>
+
+struct drmcgrp {
+	struct cgroup_subsys_state	css;
+};
+
+static inline struct drmcgrp *css_drmcgrp(struct cgroup_subsys_state *css)
+{
+	return css ? container_of(css, struct drmcgrp, css) : NULL;
+}
+
+static inline struct drmcgrp *get_drmcgrp(struct task_struct *task)
+{
+	return css_drmcgrp(task_get_css(task, drm_cgrp_id));
+}
+
+
+static inline struct drmcgrp *parent_drmcgrp(struct drmcgrp *cg)
+{
+	return css_drmcgrp(cg->css.parent);
+}
+
+#endif	/* CONFIG_CGROUP_DRM */
+#endif	/* _CGROUP_DRM_H */
diff --git a/include/linux/cgroup_subsys.h b/include/linux/cgroup_subsys.h
index acb77dcff3b4..ddedad809e8b 100644
--- a/include/linux/cgroup_subsys.h
+++ b/include/linux/cgroup_subsys.h
@@ -61,6 +61,10 @@ SUBSYS(pids)
 SUBSYS(rdma)
 #endif
 
+#if IS_ENABLED(CONFIG_CGROUP_DRM)
+SUBSYS(drm)
+#endif
+
 /*
  * The following subsystems are not supported on the default hierarchy.
  */
diff --git a/init/Kconfig b/init/Kconfig
index a4112e95724a..bee1e164443a 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -836,6 +836,11 @@ config CGROUP_RDMA
 	  Attaching processes with active RDMA resources to the cgroup
 	  hierarchy is allowed even if can cross the hierarchy's limit.
 
+config CGROUP_DRM
+	bool "DRM controller (EXPERIMENTAL)"
+	help
+	  Provides accounting and enforcement of resources in the DRM subsystem.
+
 config CGROUP_FREEZER
 	bool "Freezer controller"
 	help
diff --git a/kernel/cgroup/Makefile b/kernel/cgroup/Makefile
index bfcdae896122..6af14bd93050 100644
--- a/kernel/cgroup/Makefile
+++ b/kernel/cgroup/Makefile
@@ -4,5 +4,6 @@ obj-y := cgroup.o rstat.o namespace.o cgroup-v1.o
 obj-$(CONFIG_CGROUP_FREEZER) += freezer.o
 obj-$(CONFIG_CGROUP_PIDS) += pids.o
 obj-$(CONFIG_CGROUP_RDMA) += rdma.o
+obj-$(CONFIG_CGROUP_DRM) += drm.o
 obj-$(CONFIG_CPUSETS) += cpuset.o
 obj-$(CONFIG_CGROUP_DEBUG) += debug.o
diff --git a/kernel/cgroup/drm.c b/kernel/cgroup/drm.c
new file mode 100644
index 000000000000..d9e194b9aead
--- /dev/null
+++ b/kernel/cgroup/drm.c
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: MIT
+// Copyright 2018 Advanced Micro Devices, Inc.
+#include <linux/slab.h>
+#include <linux/cgroup.h>
+#include <linux/cgroup_drm.h>
+
+static u64 drmcgrp_test_read(struct cgroup_subsys_state *css,
+					struct cftype *cft)
+{
+	return 88;
+}
+
+static void drmcgrp_css_free(struct cgroup_subsys_state *css)
+{
+	struct drmcgrp *drmcgrp = css_drmcgrp(css);
+
+	kfree(css_drmcgrp(css));
+}
+
+static struct cgroup_subsys_state *
+drmcgrp_css_alloc(struct cgroup_subsys_state *parent_css)
+{
+	struct drmcgrp *drmcgrp;
+
+	drmcgrp = kzalloc(sizeof(struct drmcgrp), GFP_KERNEL);
+	if (!drmcgrp)
+		return ERR_PTR(-ENOMEM);
+
+	return &drmcgrp->css;
+}
+
+struct cftype files[] = {
+	{
+		.name = "drm_test",
+		.read_u64 = drmcgrp_test_read,
+	},
+	{ }	/* terminate */
+};
+
+struct cgroup_subsys drm_cgrp_subsys = {
+	.css_alloc	= drmcgrp_css_alloc,
+	.css_free	= drmcgrp_css_free,
+	.early_init	= false,
+	.legacy_cftypes	= files,
+	.dfl_cftypes	= files,
+};
-- 
2.19.1