[CI 03/12] dma-fence: Add callback transfer helper

[Tvrtko Ursulin]

From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

...

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 drivers/dma-buf/dma-fence.c | 16 ++++++++++++++++
 include/linux/dma-fence.h   |  4 ++++
 2 files changed, 20 insertions(+)

diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
index ea4a1f82c9bf..3d254ddef516 100644
--- a/drivers/dma-buf/dma-fence.c
+++ b/drivers/dma-buf/dma-fence.c
@@ -977,3 +977,19 @@ dma_fence_init(struct dma_fence *fence, const struct dma_fence_ops *ops,
 	trace_dma_fence_init(fence);
 }
 EXPORT_SYMBOL(dma_fence_init);
+
+void
+__dma_fence_cb_transfer(struct dma_fence *from,
+			struct dma_fence_cb *cb,
+			struct dma_fence *to)
+{
+	lockdep_assert_held(to->lock);
+
+	if (from) {
+		lockdep_assert_held(from->lock);
+		list_move_tail(&cb->node, &to->cb_list);
+	} else {
+		list_add_tail(&cb->node, &to->cb_list);
+	}
+}
+EXPORT_SYMBOL(__dma_fence_cb_transfer);
diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h
index 35933e0ae62c..00e54ed61b2c 100644
--- a/include/linux/dma-fence.h
+++ b/include/linux/dma-fence.h
@@ -636,4 +636,8 @@ static inline void __dma_fence_cb_init(struct dma_fence_cb *cb,
 	cb->func = func;
 }
 
+void __dma_fence_cb_transfer(struct dma_fence *from,
+			     struct dma_fence_cb *cb,
+			     struct dma_fence *to);
+
 #endif /* __LINUX_DMA_FENCE_H */
-- 
2.34.1