drm/amd: Set num IP blocks to 0 if discovery fails

If discovery has failed for any reason (such as no support for a block)
then there is no need to unwind all the IP blocks in fini. In this
condition there can actually be failures during the unwind too.

Reset num_ip_blocks to zero during failure path and skip the unnecessary
cleanup path.

Suggested-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit fae5984)
Cc: stable@vger.kernel.org

Author: superm1

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

@@ -2690,8 +2690,10 @@ static int amdgpu_device_ip_early_init(struct amdgpu_device *adev)
 		break;
 	default:
 		r = amdgpu_discovery_set_ip_blocks(adev);
-		if (r)
+		if (r) {
+			adev->num_ip_blocks = 0;
 			return r;
+		}
 		break;
 	}
 

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

@@ -83,7 +83,7 @@ void amdgpu_driver_unload_kms(struct drm_device *dev)
 {
 	struct amdgpu_device *adev = drm_to_adev(dev);
 
-	if (adev == NULL)
+	if (adev == NULL || !adev->num_ip_blocks)
 		return;
 
 	amdgpu_unregister_gpu_instance(adev);