From: Dave Airlie <airlied@gmail.com>
Date: Fri, 6 Jul 2012 17:06:42 +0000 (+0100)
Subject: drm: fail gracefully when proc isn't setup.
X-Git-Tag: v3.12-rc1~2665^2~38
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=49099c4991da3c94773f888aea2e9d27b8a7c6d1;p=kernel%2Fkernel-generic.git

drm: fail gracefully when proc isn't setup.

If drm can't find proc it should fail more gracefully, than just
oopsing, this tests drm_class is NULL, and sets it to NULL in the
fail paths.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
---

diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c
index 45cf1dd..45ac8d6 100644
--- a/drivers/gpu/drm/drm_sysfs.c
+++ b/drivers/gpu/drm/drm_sysfs.c
@@ -134,6 +134,7 @@ void drm_sysfs_destroy(void)
 		return;
 	class_remove_file(drm_class, &class_attr_version.attr);
 	class_destroy(drm_class);
+	drm_class = NULL;
 }
 
 /**
@@ -554,6 +555,9 @@ void drm_sysfs_device_remove(struct drm_minor *minor)
 
 int drm_class_device_register(struct device *dev)
 {
+	if (!drm_class || IS_ERR(drm_class))
+		return -ENOENT;
+
 	dev->class = drm_class;
 	return device_register(dev);
 }