dma-buf: add dma_fence_chain_contained helper

It's a reoccurring pattern that we need to extract the fence
from a dma_fence_chain object. Add a helper for this.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220204100429.2049-6-christian.koenig@amd.com

diff --git a/drivers/dma-buf/dma-fence-chain.c b/drivers/dma-buf/dma-fence-chain.c
index 084c692..06f8ef9 100644 (file)
--- a/drivers/dma-buf/dma-fence-chain.c
+++ b/drivers/dma-buf/dma-fence-chain.c
@@ -148,8 +148,7 @@ static bool dma_fence_chain_enable_signaling(struct dma_fence *fence)
 
        dma_fence_get(&head->base);
        dma_fence_chain_for_each(fence, &head->base) {
-               struct dma_fence_chain *chain = to_dma_fence_chain(fence);
-               struct dma_fence *f = chain ? chain->fence : fence;
+               struct dma_fence *f = dma_fence_chain_contained(fence);
 
                dma_fence_get(f);
                if (!dma_fence_add_callback(f, &head->cb, dma_fence_chain_cb)) {
@@ -165,8 +164,7 @@ static bool dma_fence_chain_enable_signaling(struct dma_fence *fence)
 static bool dma_fence_chain_signaled(struct dma_fence *fence)
 {
        dma_fence_chain_for_each(fence, fence) {
-               struct dma_fence_chain *chain = to_dma_fence_chain(fence);
-               struct dma_fence *f = chain ? chain->fence : fence;
+               struct dma_fence *f = dma_fence_chain_contained(fence);
 
                if (!dma_fence_is_signaled(f)) {
                        dma_fence_put(fence);

diff --git a/include/linux/dma-fence-chain.h b/include/linux/dma-fence-chain.h
index ee906b6..10d51bc 100644 (file)
--- a/include/linux/dma-fence-chain.h
+++ b/include/linux/dma-fence-chain.h
@@ -67,6 +67,21 @@ to_dma_fence_chain(struct dma_fence *fence)
 }
 
 /**
+ * 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.