[PATCH 2/4] drm: Allow creating blob properties without copy

[Daniel Stone]

Make the data parameter to drm_property_create_blob optional; if
omitted, the copy will be skipped and the data will be empty.

Signed-off-by: Daniel Stone <daniels at collabora.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst at intel.com>
---
 drivers/gpu/drm/drm_crtc.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 6f3cafb..f7b075b 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -4204,6 +4204,16 @@ done:
 	return ret;
 }
 
+/**
+ * drm_property_create_blob - Create new blob property
+ *
+ * Creates a new blob property for a specified DRM device, optionally
+ * copying data.
+ *
+ * @param dev DRM device to create property for
+ * @param length Length to allocate for blob data
+ * @param data If specified, copies data into blob
+ */
 struct drm_property_blob *
 drm_property_create_blob(struct drm_device *dev, size_t length,
 			 const void *data)
@@ -4211,7 +4221,7 @@ drm_property_create_blob(struct drm_device *dev, size_t length,
 	struct drm_property_blob *blob;
 	int ret;
 
-	if (!length || !data)
+	if (!length)
 		return NULL;
 
 	blob = kzalloc(sizeof(struct drm_property_blob)+length, GFP_KERNEL);
@@ -4221,7 +4231,8 @@ drm_property_create_blob(struct drm_device *dev, size_t length,
 	blob->length = length;
 	blob->dev = dev;
 
-	memcpy(blob->data, data, length);
+	if (data)
+		memcpy(blob->data, data, length);
 
 	mutex_lock(&dev->mode_config.blob_lock);
 
-- 
2.4.0