[mutter/gnome-3-36] renderer-native: Don't leak DMA buffer CoglFramebuffer

[Jonas Ådahl <jadahl src gnome org>]

commit 0d9ded403f6e285b6e928c5c850e0481b3a69291
Author: Jonas Ådahl <jadahl gmail com>
Date:   Tue Jun 2 18:34:57 2020 +0200

    renderer-native: Don't leak DMA buffer CoglFramebuffer
    
    When we created the DMA buffer backed CoglFramebuffer, we handed it over
    to CoglDmaBufHandle which took its own reference. What we failed to do
    was to release our own reference to it, effectively leaking it.
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1283
    (cherry picked from commit c823b5ddba18d30e1fdb74d6764cd40637dc4054)

 src/backends/native/meta-renderer-native.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)
---
diff --git a/src/backends/native/meta-renderer-native.c b/src/backends/native/meta-renderer-native.c
index 8d82ad7c42..e94562b286 100644
--- a/src/backends/native/meta-renderer-native.c
+++ b/src/backends/native/meta-renderer-native.c
@@ -2146,6 +2146,7 @@ meta_renderer_native_create_dma_buf (CoglRenderer  *cogl_renderer,
     case META_RENDERER_NATIVE_MODE_GBM:
       {
         CoglFramebuffer *dmabuf_fb;
+        CoglDmaBufHandle *dmabuf_handle;
         struct gbm_bo *new_bo;
         int dmabuf_fd = -1;
 
@@ -2182,8 +2183,11 @@ meta_renderer_native_create_dma_buf (CoglRenderer  *cogl_renderer,
         if (!dmabuf_fb)
           return NULL;
 
-        return cogl_dma_buf_handle_new (dmabuf_fb, dmabuf_fd, new_bo,
-                                        (GDestroyNotify) gbm_bo_destroy);
+        dmabuf_handle =
+          cogl_dma_buf_handle_new (dmabuf_fb, dmabuf_fd, new_bo,
+                                   (GDestroyNotify) gbm_bo_destroy);
+        cogl_object_unref (dmabuf_fb);
+        return dmabuf_handle;
       }
       break;
 #ifdef HAVE_EGL_DEVICE