[PATCH] drm/amdgpu: unpack dma_fence_chain containers during sync

[Christian König]

This allows for optimizing the CPU round trip away.

Signed-off-by: Christian König <christian.koenig at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c   |  2 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c | 27 ++++++++++++++++++++++++
 drivers/gpu/drm/amd/amdgpu/amdgpu_sync.h |  1 +
 3 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
index 79342976fa76..68f9a4adf5d2 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -1014,7 +1014,7 @@ static int amdgpu_syncobj_lookup_and_add_to_sync(struct amdgpu_cs_parser *p,
 		return r;
 	}
 
-	r = amdgpu_sync_fence(&p->job->sync, fence);
+	r = amdgpu_sync_fence_chain(&p->job->sync, fence);
 	dma_fence_put(fence);
 
 	return r;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c
index 8ea6c49529e7..d0d64af06f54 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c
@@ -28,6 +28,8 @@
  *    Christian König <christian.koenig at amd.com>
  */
 
+#include <linux/dma-fence-chain.h>
+
 #include "amdgpu.h"
 #include "amdgpu_trace.h"
 #include "amdgpu_amdkfd.h"
@@ -169,6 +171,31 @@ int amdgpu_sync_fence(struct amdgpu_sync *sync, struct dma_fence *f)
 	return 0;
 }
 
+/**
+ * amdgpu_sync_fence_chain - unpack dma_fence_chain and sync
+ *
+ * @sync: sync object to add fence to
+ * @f: potential dma_fence_chain to sync to.
+ *
+ * Add the fences inside the chain to the sync object.
+ */
+int amdgpu_sync_fence_chain(struct amdgpu_sync *sync, struct dma_fence *f)
+{
+	int r;
+
+	dma_fence_chain_for_each(f, f) {
+		if (dma_fence_is_signaled(f))
+			continue;
+
+		r = amdgpu_sync_fence(sync, f);
+		if (r) {
+			dma_fence_put(f);
+			return r;
+		}
+	}
+	return 0;
+}
+
 /**
  * amdgpu_sync_vm_fence - remember to sync to this VM fence
  *
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.h
index 7c0fe20c470d..b142175b65b6 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.h
@@ -48,6 +48,7 @@ struct amdgpu_sync {
 
 void amdgpu_sync_create(struct amdgpu_sync *sync);
 int amdgpu_sync_fence(struct amdgpu_sync *sync, struct dma_fence *f);
+int amdgpu_sync_fence_chain(struct amdgpu_sync *sync, struct dma_fence *f);
 int amdgpu_sync_vm_fence(struct amdgpu_sync *sync, struct dma_fence *fence);
 int amdgpu_sync_resv(struct amdgpu_device *adev, struct amdgpu_sync *sync,
 		     struct dma_resv *resv, enum amdgpu_sync_mode mode,
-- 
2.25.1