From 742b198eb7216c79f9ed21ee33a4c526fc62f45f Mon Sep 17 00:00:00 2001
From: Odin Ugedal <odin@ugedal.com>
Date: Fri, 3 Apr 2020 19:55:28 +0200
Subject: device_cgroup: Cleanup cgroup eBPF device filter code
Git-commit: eec8fd0277e37cf447b88c6be181e81df867bcf1
Patch-mainline: v5.7
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322

Original cgroup v2 eBPF code for filtering device access made it
possible to compile with CONFIG_CGROUP_DEVICE=n and still use the eBPF
filtering. Change
commit 4b7d4d453fc4 ("device_cgroup: Export devcgroup_check_permission")
reverted this, making it required to set it to y.

Since the device filtering (and all the docs) for cgroup v2 is no longer
a "device controller" like it was in v1, someone might compile their
kernel with CONFIG_CGROUP_DEVICE=n. Then (for linux 5.5+) the eBPF
filter will not be invoked, and all processes will be allowed access
to all devices, no matter what the eBPF filter says.

Signed-off-by: Odin Ugedal <odin@ugedal.com>
Acked-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/amd/amdkfd/kfd_priv.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
index 4a3049841086..c24cad3c64ed 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
@@ -1050,7 +1050,7 @@ void kfd_dec_compute_active(struct kfd_dev *dev);
 /* Check with device cgroup if @kfd device is accessible */
 static inline int kfd_devcgroup_check_permission(struct kfd_dev *kfd)
 {
-#if defined(CONFIG_CGROUP_DEVICE)
+#if defined(CONFIG_CGROUP_DEVICE) || defined(CONFIG_CGROUP_BPF)
 	struct drm_device *ddev = kfd->ddev;
 
 	return devcgroup_check_permission(DEVCG_DEV_CHAR, ddev->driver->major,
-- 
2.28.0