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drm/sched: add rcu_barrier after entity fini 

To free the fence from the amdgpu_fence_slab, need twice call_rcu, to avoid
the amdgpu_fence_slab_fini call kmem_cache_destroy(amdgpu_fence_slab) before
kmem_cache_free(amdgpu_fence_slab, fence), add rcu_barrier after drm_sched_entity_fini.

The kmem_cache_free(amdgpu_fence_slab, fence)'s call trace as below:
1.drm_sched_entity_fini ->
drm_sched_entity_cleanup ->
dma_fence_put(entity->last_scheduled) ->
drm_sched_fence_release_finished ->
drm_sched_fence_release_scheduled ->
call_rcu(&fence->finished.rcu, drm_sched_fence_free)

2.drm_sched_fence_free ->
dma_fence_put(fence->parent) ->
amdgpu_fence_release ->
call_rcu(&f->rcu, amdgpu_fence_free) ->
kmem_cache_free(amdgpu_fence_slab, fence);

v2:put the barrier before the kmem_cache_destroy
v3:put the dma_fence_put(fence->parent) before call_rcu in
drm_sched_fence_release_scheduled

Signed-off-by: Emily Deng <Emily.Deng@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
hifive-unleashed-5.1
Emily Deng 2018-05-23 15:53:03 +08:00 committed by Alex Deucher
parent 806f043f02
commit 52bf20f414
1 changed files with 1 additions and 1 deletions
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2
drivers/gpu/drm/scheduler/sched_fence.c
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@ -98,7 +98,6 @@ static void drm_sched_fence_free(struct rcu_head *rcu)
struct dma_fence *f = container_of(rcu, struct dma_fence, rcu);
struct drm_sched_fence *fence = to_drm_sched_fence(f);
dma_fence_put(fence->parent);
kmem_cache_free(sched_fence_slab, fence);
}
@ -114,6 +113,7 @@ static void drm_sched_fence_release_scheduled(struct dma_fence *f)
{
struct drm_sched_fence *fence = to_drm_sched_fence(f);
dma_fence_put(fence->parent);
call_rcu(&fence->finished.rcu, drm_sched_fence_free);
}