1 files changed, 24 insertions, 6 deletions

diff --git a/include/linux/dma-fence-chain.h b/include/linux/dma-fence-chain.h
index 54fe3443fd2c..68c3c1e41014 100644
--- a/include/linux/dma-fence-chain.h
+++ b/include/linux/dma-fence-chain.h
@@ -49,7 +49,6 @@ struct dma_fence_chain {
 	spinlock_t lock;
 };
 
-extern const struct dma_fence_ops dma_fence_chain_ops;
 
 /**
  * to_dma_fence_chain - cast a fence to a dma_fence_chain
@@ -61,21 +60,38 @@ extern const struct dma_fence_ops dma_fence_chain_ops;
 static inline struct dma_fence_chain *
 to_dma_fence_chain(struct dma_fence *fence)
 {
-	if (!fence || fence->ops != &dma_fence_chain_ops)
+	if (!fence || !dma_fence_is_chain(fence))
 		return NULL;
 
 	return container_of(fence, struct dma_fence_chain, base);
 }
 
 /**
+ * dma_fence_chain_contained - return the contained fence
+ * @fence: the fence to test
+ *
+ * If the fence is a dma_fence_chain the function returns the fence contained
+ * inside the chain object, otherwise it returns the fence itself.
+ */
+static inline struct dma_fence *
+dma_fence_chain_contained(struct dma_fence *fence)
+{
+	struct dma_fence_chain *chain = to_dma_fence_chain(fence);
+
+	return chain ? chain->fence : fence;
+}
+
+/**
  * dma_fence_chain_alloc
  *
  * Returns a new struct dma_fence_chain object or NULL on failure.
+ *
+ * This specialized allocator has to be a macro for its allocations to be
+ * accounted separately (to have a separate alloc_tag). The typecast is
+ * intentional to enforce typesafety.
  */
-static inline struct dma_fence_chain *dma_fence_chain_alloc(void)
-{
-	return kmalloc(sizeof(struct dma_fence_chain), GFP_KERNEL);
-};
+#define dma_fence_chain_alloc()	\
+		((struct dma_fence_chain *)kmalloc(sizeof(struct dma_fence_chain), GFP_KERNEL))
 
 /**
  * dma_fence_chain_free
@@ -98,6 +114,8 @@ static inline void dma_fence_chain_free(struct dma_fence_chain *chain)
  *
  * Iterate over all fences in the chain. We keep a reference to the current
  * fence while inside the loop which must be dropped when breaking out.
+ *
+ * For a deep dive iterator see dma_fence_unwrap_for_each().
  */
 #define dma_fence_chain_for_each(iter, head)	\
 	for (iter = dma_fence_get(head); iter; \