drm: Use kvzalloc for allocating blob property memory

commit 718b5406 upstream.

The property size may be controlled by userspace, can be large (I've
seen failure with order 4, i.e. 16 pages / 64 KB) and doesn't need to be
physically contiguous.
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180629142710.2069-1-michel@daenzer.net
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/gpu/drm/drm_property.c

@@ -516,7 +516,7 @@ static void drm_property_free_blob(struct kref *kref)
 
 	drm_mode_object_unregister(blob->dev, &blob->base);
 
-	kfree(blob);
+	kvfree(blob);
 }
 
 /**
@@ -543,7 +543,7 @@ drm_property_create_blob(struct drm_device *dev, size_t length,
 	if (!length || length > ULONG_MAX - sizeof(struct drm_property_blob))
 		return ERR_PTR(-EINVAL);
 
-	blob = kzalloc(sizeof(struct drm_property_blob)+length, GFP_KERNEL);
+	blob = kvzalloc(sizeof(struct drm_property_blob)+length, GFP_KERNEL);
 	if (!blob)
 		return ERR_PTR(-ENOMEM);
 
@@ -559,7 +559,7 @@ drm_property_create_blob(struct drm_device *dev, size_t length,
 	ret = __drm_mode_object_add(dev, &blob->base, DRM_MODE_OBJECT_BLOB,
 				    true, drm_property_free_blob);
 	if (ret) {
-		kfree(blob);
+		kvfree(blob);
 		return ERR_PTR(-EINVAL);
 	}