[PATCH 5/5] drm: use dma_fence_unwrap_merge() in drm_syncobj

[Christian König]

The unwrap merge function is now intended for this use case.

Signed-off-by: Christian König <christian.koe...@amd.com>
Reviewed-by: Daniel Vetter <daniel.vet...@ffwll.ch>
---
 drivers/gpu/drm/drm_syncobj.c | 57 +++++------------------------------
 1 file changed, 7 insertions(+), 50 deletions(-)

diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
index 7e48dcd1bee4..bbad9e4696e7 100644
--- a/drivers/gpu/drm/drm_syncobj.c
+++ b/drivers/gpu/drm/drm_syncobj.c
@@ -184,6 +184,7 @@
  */
 
 #include <linux/anon_inodes.h>
+#include <linux/dma-fence-unwrap.h>
 #include <linux/file.h>
 #include <linux/fs.h>
 #include <linux/sched/signal.h>
@@ -853,57 +854,12 @@ drm_syncobj_fd_to_handle_ioctl(struct drm_device *dev, 
void *data,
                                        &args->handle);
 }
 
-
-/*
- * Try to flatten a dma_fence_chain into a dma_fence_array so that it can be
- * added as timeline fence to a chain again.
- */
-static int drm_syncobj_flatten_chain(struct dma_fence **f)
-{
-       struct dma_fence_chain *chain = to_dma_fence_chain(*f);
-       struct dma_fence *tmp, **fences;
-       struct dma_fence_array *array;
-       unsigned int count;
-
-       if (!chain)
-               return 0;
-
-       count = 0;
-       dma_fence_chain_for_each(tmp, &chain->base)
-               ++count;
-
-       fences = kmalloc_array(count, sizeof(*fences), GFP_KERNEL);
-       if (!fences)
-               return -ENOMEM;
-
-       count = 0;
-       dma_fence_chain_for_each(tmp, &chain->base)
-               fences[count++] = dma_fence_get(tmp);
-
-       array = dma_fence_array_create(count, fences,
-                                      dma_fence_context_alloc(1),
-                                      1, false);
-       if (!array)
-               goto free_fences;
-
-       dma_fence_put(*f);
-       *f = &array->base;
-       return 0;
-
-free_fences:
-       while (count--)
-               dma_fence_put(fences[count]);
-
-       kfree(fences);
-       return -ENOMEM;
-}
-
 static int drm_syncobj_transfer_to_timeline(struct drm_file *file_private,
                                            struct drm_syncobj_transfer *args)
 {
        struct drm_syncobj *timeline_syncobj = NULL;
+       struct dma_fence *fence, *tmp;
        struct dma_fence_chain *chain;
-       struct dma_fence *fence;
        int ret;
 
        timeline_syncobj = drm_syncobj_find(file_private, args->dst_handle);
@@ -912,13 +868,14 @@ static int drm_syncobj_transfer_to_timeline(struct 
drm_file *file_private,
        }
        ret = drm_syncobj_find_fence(file_private, args->src_handle,
                                     args->src_point, args->flags,
-                                    &fence);
+                                    &tmp);
        if (ret)
                goto err_put_timeline;
 
-       ret = drm_syncobj_flatten_chain(&fence);
-       if (ret)
-               goto err_free_fence;
+       fence = dma_fence_unwrap_merge(tmp);
+       dma_fence_put(tmp);
+       if (!fence)
+               goto err_put_timeline;
 
        chain = dma_fence_chain_alloc();
        if (!chain) {
-- 
2.25.1