It avoids duplicated code and allows to output a warning.

---
v4: move check inside the existing if (enable) test
---

Signed-off-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 13 ++++---------
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c    |  5 +++++
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 362ab2b34498..98aead91b98b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -3158,9 +3158,7 @@ static int amdgpu_device_ip_init(struct amdgpu_device *adev)
 	if (r)
 		goto init_failed;
 
-	if (adev->mman.buffer_funcs_ring &&
-	    adev->mman.buffer_funcs_ring->sched.ready)
-		amdgpu_ttm_set_buffer_funcs_status(adev, true);
+	amdgpu_ttm_set_buffer_funcs_status(adev, true);
 
 	/* Don't init kfd if whole hive need to be reset during init */
 	if (adev->init_lvl->level != AMDGPU_INIT_LEVEL_MINIMAL_XGMI) {
@@ -4052,8 +4050,7 @@ static int amdgpu_device_ip_resume(struct amdgpu_device *adev)
 
 	r = amdgpu_device_ip_resume_phase2(adev);
 
-	if (adev->mman.buffer_funcs_ring->sched.ready)
-		amdgpu_ttm_set_buffer_funcs_status(adev, true);
+	amdgpu_ttm_set_buffer_funcs_status(adev, true);
 
 	if (r)
 		return r;
@@ -5199,8 +5196,7 @@ int amdgpu_device_suspend(struct drm_device *dev, bool notify_clients)
 	return 0;
 
 unwind_evict:
-	if (adev->mman.buffer_funcs_ring->sched.ready)
-		amdgpu_ttm_set_buffer_funcs_status(adev, true);
+	amdgpu_ttm_set_buffer_funcs_status(adev, true);
 	amdgpu_fence_driver_hw_init(adev);
 
 unwind_userq:
@@ -5931,8 +5927,7 @@ int amdgpu_device_reinit_after_reset(struct amdgpu_reset_context *reset_context)
 				if (r)
 					goto out;
 
-				if (tmp_adev->mman.buffer_funcs_ring->sched.ready)
-					amdgpu_ttm_set_buffer_funcs_status(tmp_adev, true);
+				amdgpu_ttm_set_buffer_funcs_status(tmp_adev, true);
 
 				r = amdgpu_device_ip_resume_phase3(tmp_adev);
 				if (r)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 7eaaf5d4db94..10943311ce94 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -2354,6 +2354,11 @@ void amdgpu_ttm_set_buffer_funcs_status(struct amdgpu_device *adev, bool enable)
 		struct amdgpu_ring *ring;
 		struct drm_gpu_scheduler *sched;
 
+		if (!adev->mman.buffer_funcs_ring || !adev->mman.buffer_funcs_ring->sched.ready) {
+			dev_warn(adev->dev, "Not enabling DMA transfers for in kernel use");
+			return;
+		}
+
 		ring = adev->mman.buffer_funcs_ring;
 		sched = &ring->sched;
 		r = amdgpu_ttm_buffer_entity_init(&adev->mman.gtt_mgr,
-- 
2.43.0