[PATCH 2/2] drm/amdgpu: properly release the eviction fences

[Prike Liang]

The following cases require releasing and deferring the
eviction fences properly

1) Detach the old eviction fences before attaching a new one.
2) Drop the eviction fence init reference.
3) Correct the attached eviction fence reference.
4) Free the eviction fence when the attached BOs are released.

Signed-off-by: Prike Liang <Prike.Liang at amd.com>
---
 .../drm/amd/amdgpu/amdgpu_eviction_fence.c    | 53 +++++++++++++++----
 .../drm/amd/amdgpu/amdgpu_eviction_fence.h    |  2 +
 drivers/gpu/drm/amd/amdgpu/amdgpu_object.c    |  1 +
 3 files changed, 45 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c
index d86e611a9ff4..a47db865c530 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c
@@ -70,11 +70,6 @@ amdgpu_eviction_fence_replace_fence(struct amdgpu_eviction_fence_mgr *evf_mgr,
 		return -ENOMEM;
 	}
 
-	/* Update the eviction fence now */
-	spin_lock(&evf_mgr->ev_fence_lock);
-	old_ef = evf_mgr->ev_fence;
-	evf_mgr->ev_fence = new_ef;
-	spin_unlock(&evf_mgr->ev_fence_lock);
 
 	/* Attach the new fence */
 	drm_exec_for_each_locked_object(exec, index, obj) {
@@ -82,6 +77,16 @@ amdgpu_eviction_fence_replace_fence(struct amdgpu_eviction_fence_mgr *evf_mgr,
 
 		if (!bo)
 			continue;
+
+		/*detach the old eviction fence first*/
+		amdgpu_eviction_fence_detach(evf_mgr, bo);
+
+		/* Update the eviction fence now */
+		spin_lock(&evf_mgr->ev_fence_lock);
+		old_ef = evf_mgr->ev_fence;
+		evf_mgr->ev_fence = new_ef;
+		spin_unlock(&evf_mgr->ev_fence_lock);
+
 		ret = amdgpu_eviction_fence_attach(evf_mgr, bo);
 		if (ret) {
 			DRM_ERROR("Failed to attch new eviction fence\n");
@@ -89,9 +94,10 @@ amdgpu_eviction_fence_replace_fence(struct amdgpu_eviction_fence_mgr *evf_mgr,
 		}
 	}
 
-	/* Free old fence */
+	/* Free the init eviction fence which was referred by the dma_init*/
 	if (old_ef)
 		dma_fence_put(&old_ef->base);
+
 	return 0;
 
 free_err:
@@ -189,7 +195,6 @@ void amdgpu_eviction_fence_destroy(struct amdgpu_eviction_fence_mgr *evf_mgr)
 int amdgpu_eviction_fence_attach(struct amdgpu_eviction_fence_mgr *evf_mgr,
 				 struct amdgpu_bo *bo)
 {
-	struct dma_fence *ef;
 	struct amdgpu_eviction_fence *ev_fence;
 	struct dma_resv *resv = bo->tbo.base.resv;
 	int ret;
@@ -205,10 +210,12 @@ int amdgpu_eviction_fence_attach(struct amdgpu_eviction_fence_mgr *evf_mgr,
 
 	spin_lock(&evf_mgr->ev_fence_lock);
 	ev_fence = evf_mgr->ev_fence;
-	if (ev_fence) {
-		ef = dma_fence_get(&ev_fence->base);
-		dma_resv_add_fence(resv, ef, DMA_RESV_USAGE_BOOKKEEP);
-	}
+	/*
+	 * The dma_resv_add_fence() already refer to the added fence, hence in this
+	 * placement needn't refer to the armed fence anymore.
+	 */
+	if (ev_fence)
+		dma_resv_add_fence(resv, &ev_fence->base, DMA_RESV_USAGE_BOOKKEEP);
 	spin_unlock(&evf_mgr->ev_fence_lock);
 
 	return 0;
@@ -224,6 +231,30 @@ void amdgpu_eviction_fence_detach(struct amdgpu_eviction_fence_mgr *evf_mgr,
 	dma_fence_put(stub);
 }
 
+void amdgpu_remove_all_eviction_fences(struct amdgpu_bo *bo)
+{
+	struct dma_resv *resv = &bo->tbo.base._resv;
+	struct dma_fence *fence, *stub;
+	struct dma_resv_iter cursor;
+
+	dma_resv_assert_held(resv);
+
+	stub = dma_fence_get_stub();
+	dma_resv_for_each_fence(&cursor, resv, DMA_RESV_USAGE_BOOKKEEP, fence) {
+		struct amdgpu_eviction_fence *ev_fence;
+
+		ev_fence = fence_to_evf(fence);
+		if (!ev_fence || !dma_fence_is_signaled(&ev_fence->base))
+			continue;
+
+		dma_resv_replace_fences(resv, fence->context, stub,
+				DMA_RESV_USAGE_BOOKKEEP);
+
+	}
+
+	dma_fence_put(stub);
+}
+
 int amdgpu_eviction_fence_init(struct amdgpu_eviction_fence_mgr *evf_mgr)
 {
 	/* This needs to be done one time per open */
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.h
index fcd867b7147d..7e6c55a334e0 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.h
@@ -42,6 +42,7 @@ struct amdgpu_eviction_fence_mgr {
 };
 
 /* Eviction fence helper functions */
+#define fence_to_evf(f)  container_of(f, struct amdgpu_eviction_fence, base)
 struct amdgpu_eviction_fence *
 amdgpu_eviction_fence_create(struct amdgpu_eviction_fence_mgr *evf_mgr);
 
@@ -66,4 +67,5 @@ amdgpu_eviction_fence_signal(struct amdgpu_eviction_fence_mgr *evf_mgr,
 int
 amdgpu_eviction_fence_replace_fence(struct amdgpu_eviction_fence_mgr *evf_mgr,
 				    struct drm_exec *exec);
+void amdgpu_remove_all_eviction_fences(struct amdgpu_bo *bo);
 #endif
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
index dbe57996a481..6d3eacffbcb9 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
@@ -1322,6 +1322,7 @@ void amdgpu_bo_release_notify(struct ttm_buffer_object *bo)
 	amdgpu_vram_mgr_set_cleared(bo->resource);
 	dma_resv_add_fence(&bo->base._resv, fence, DMA_RESV_USAGE_KERNEL);
 	dma_fence_put(fence);
+	amdgpu_remove_all_eviction_fences(abo);
 
 out:
 	dma_resv_unlock(&bo->base._resv);
-- 
2.34.1