[PATCH 3/5] drm/amdgpu: Add amdgpu_sync_wait

[Harish Kasiviswanathan]

Helper function useful for CPU update of VM page tables. Also useful if
kernel have to synchronously wait till VM page tables are updated.

Signed-off-by: Harish Kasiviswanathan <Harish.Kasiviswanathan at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c | 19 +++++++++++++++++++
 drivers/gpu/drm/amd/amdgpu/amdgpu_sync.h |  1 +
 2 files changed, 20 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c
index 5c8d302..e5b202e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c
@@ -296,6 +296,25 @@ struct fence *amdgpu_sync_get_fence(struct amdgpu_sync *sync)
 	return NULL;
 }
 
+int amdgpu_sync_wait(struct amdgpu_sync *sync)
+{
+	struct amdgpu_sync_entry *e;
+	struct hlist_node *tmp;
+	int i, r;
+
+	hash_for_each_safe(sync->fences, i, tmp, e, node) {
+		r = fence_wait(e->fence, false);
+		if (r)
+			return r;
+
+		hash_del(&e->node);
+		fence_put(e->fence);
+		kmem_cache_free(amdgpu_sync_slab, e);
+	}
+
+	return 0;
+}
+
 /**
  * amdgpu_sync_free - free the sync object
  *
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.h
index 405f379..6c9c489 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.h
@@ -49,6 +49,7 @@ int amdgpu_sync_resv(struct amdgpu_device *adev,
 struct fence *amdgpu_sync_peek_fence(struct amdgpu_sync *sync,
 				     struct amdgpu_ring *ring);
 struct fence *amdgpu_sync_get_fence(struct amdgpu_sync *sync);
+int amdgpu_sync_wait(struct amdgpu_sync *sync);
 void amdgpu_sync_free(struct amdgpu_sync *sync);
 int amdgpu_sync_init(void);
 void amdgpu_sync_fini(void);
-- 
1.9.1