drm/amdgpu: handle eviction fence race

The eviction process can get into a race condition between the eviction
fence suspend work (which replaces the old fence with new) and kms_close
(which destroys the fence and doesn't expect a new one).

This patch:
- adds a flag to indicate that fd is closing, so fence replacement is
  not required (evf_mgr->fd_closing)
- adds a flush_work() during the ev_fence_destroy routine

V2: Addressed review comments from Christian:
    - Do not use mutex to sync
    - Use flush_work and wait for suspend_work to be done

V3: Fixed state machine for queue->active, which adds into race between
    suspend/resume and queue ops

Cc: Alex Deucher <[email protected]>
Cc: Christian König <[email protected]>
Reviewed-by: Christian König <[email protected]>
Signed-off-by: Shashank Sharma <[email protected]>
Signed-off-by: Arvind Yadav <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>

1 files changed, 5 insertions, 4 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/mes_v11_0_userqueue.c b/drivers/gpu/drm/amd/amdgpu/mes_v11_0_userqueue.c
index ee0a757fcfa3..b1b7bc47d39f 100644
--- a/drivers/gpu/drm/amd/amdgpu/mes_v11_0_userqueue.c
+++ b/drivers/gpu/drm/amd/amdgpu/mes_v11_0_userqueue.c
@@ -139,6 +139,7 @@ static int mes_v11_0_userq_map(struct amdgpu_userq_mgr *uq_mgr,
 		return r;
 	}
 
+	queue->queue_active = true;
 	DRM_DEBUG_DRIVER("Queue (doorbell:%d) mapped successfully\n", userq_props->doorbell_index);
 	return 0;
 }
@@ -160,6 +161,7 @@ static void mes_v11_0_userq_unmap(struct amdgpu_userq_mgr *uq_mgr,
 	amdgpu_mes_unlock(&adev->mes);
 	if (r)
 		DRM_ERROR("Failed to unmap queue in HW, err (%d)\n", r);
+	queue->queue_active = false;
 }
 
 static int mes_v11_0_userq_create_ctx_space(struct amdgpu_userq_mgr *uq_mgr,
@@ -331,7 +333,6 @@ static int mes_v11_0_userq_mqd_create(struct amdgpu_userq_mgr *uq_mgr,
 		goto free_ctx;
 	}
 
-	queue->queue_active = true;
 	return 0;
 
 free_ctx:
@@ -350,12 +351,12 @@ static void
 mes_v11_0_userq_mqd_destroy(struct amdgpu_userq_mgr *uq_mgr,
 			    struct amdgpu_usermode_queue *queue)
 {
-	mes_v11_0_userq_unmap(uq_mgr, queue);
-	amdgpu_bo_unref(&queue->wptr_obj.obj);
+	if (queue->queue_active)
+		mes_v11_0_userq_unmap(uq_mgr, queue);
+
 	amdgpu_userqueue_destroy_object(uq_mgr, &queue->fw_obj);
 	kfree(queue->userq_prop);
 	amdgpu_userqueue_destroy_object(uq_mgr, &queue->mqd);
-	queue->queue_active = false;
 }
 
 static int mes_v11_0_userq_suspend(struct amdgpu_userq_mgr *uq_mgr,