drm/amdgpu: enable eviction fence

This patch enables attachment and detachment of eviction fences.
This is just a fork of eviction fence enabling code from the first
patch of the series so that the CI testing can happen on fully
fledged code.

Cc: Alex Deucher <[e-mail]>
Cc: Christian Koenig <[e-mail]>
Reviewed-by: Christian Koenig <[e-mail]>
Signed-off-by: Shashank Sharma <[e-mail]>
Signed-off-by: Arvind Yadav <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c

···
 	if (!ev_fence)
 		return;
 
+	dma_fence_wait(&ev_fence->base, false);
+
 	/* Last unref of ev_fence */
 	dma_fence_put(&evf_mgr->ev_fence->base);
 }

drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c

···
 	else
 		++bo_va->ref_count;
 
+	/* attach gfx eviction fence */
+	r = amdgpu_eviction_fence_attach(&fpriv->evf_mgr, abo);
+	if (r) {
+		DRM_DEBUG_DRIVER("Failed to attach eviction fence to BO\n");
+		return r;
+	}
+
 	amdgpu_bo_unreserve(abo);
 
 	/* Validate and add eviction fence to DMABuf imports with dynamic
···
 	struct amdgpu_bo_va *bo_va;
 	struct drm_exec exec;
 	long r;
+
+	if (!amdgpu_vm_is_bo_always_valid(vm, bo))
+		amdgpu_eviction_fence_detach(&fpriv->evf_mgr, bo);
 
 	drm_exec_init(&exec, DRM_EXEC_IGNORE_DUPLICATES, 0);
 	drm_exec_until_all_locked(&exec) {