drm/amdgpu: fence wait old rcu slot
since the rcu slot was initialized to be num_hw_submission,
if command submission doesn't use scheduler, this limitation
will be invalid like uvd test.
Signed-off-by: Chunming Zhou <David1.Zhou@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
index 4303b44..d81f1f4 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
@@ -121,7 +121,7 @@
{
struct amdgpu_device *adev = ring->adev;
struct amdgpu_fence *fence;
- struct fence **ptr;
+ struct fence *old, **ptr;
uint32_t seq;
fence = kmem_cache_alloc(amdgpu_fence_slab, GFP_KERNEL);
@@ -141,7 +141,11 @@
/* This function can't be called concurrently anyway, otherwise
* emitting the fence would mess up the hardware ring buffer.
*/
- BUG_ON(rcu_dereference_protected(*ptr, 1));
+ old = rcu_dereference_protected(*ptr, 1);
+ if (old && !fence_is_signaled(old)) {
+ DRM_INFO("rcu slot is busy\n");
+ fence_wait(old, false);
+ }
rcu_assign_pointer(*ptr, fence_get(&fence->base));
