drm/i915: Move allocation of various workqueues earlier during init

Workqueue initalization doesn't depend on any other device specific
resource, so move it close to the beginning, so we don't need to
consider them when thinking about dependencies for other resources.

Also factor out things to separate init/cleanup functions to make
i915_driver_load()/unload() clearer, atm it's somewhat difficult to
follow there in what order resources are inited/cleaned-up.
Suggested-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NDavid Weinehall <david.weinehall@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453209992-25995-6-git-send-email-imre.deak@intel.com

drivers/gpu/drm/i915/i915_dma.c

@@ -856,6 +856,54 @@ static void intel_init_dpio(struct drm_i915_private *dev_priv)
 	}
 }
 
+static int i915_workqueues_init(struct drm_i915_private *dev_priv)
+{
+	/*
+	 * The i915 workqueue is primarily used for batched retirement of
+	 * requests (and thus managing bo) once the task has been completed
+	 * by the GPU. i915_gem_retire_requests() is called directly when we
+	 * need high-priority retirement, such as waiting for an explicit
+	 * bo.
+	 *
+	 * It is also used for periodic low-priority events, such as
+	 * idle-timers and recording error state.
+	 *
+	 * All tasks on the workqueue are expected to acquire the dev mutex
+	 * so there is no point in running more than one instance of the
+	 * workqueue at any time.  Use an ordered one.
+	 */
+	dev_priv->wq = alloc_ordered_workqueue("i915", 0);
+	if (dev_priv->wq == NULL)
+		goto out_err;
+
+	dev_priv->hotplug.dp_wq = alloc_ordered_workqueue("i915-dp", 0);
+	if (dev_priv->hotplug.dp_wq == NULL)
+		goto out_free_wq;
+
+	dev_priv->gpu_error.hangcheck_wq =
+		alloc_ordered_workqueue("i915-hangcheck", 0);
+	if (dev_priv->gpu_error.hangcheck_wq == NULL)
+		goto out_free_dp_wq;
+
+	return 0;
+
+out_free_dp_wq:
+	destroy_workqueue(dev_priv->hotplug.dp_wq);
+out_free_wq:
+	destroy_workqueue(dev_priv->wq);
+out_err:
+	DRM_ERROR("Failed to allocate workqueues.\n");
+
+	return -ENOMEM;
+}
+
+static void i915_workqueues_cleanup(struct drm_i915_private *dev_priv)
+{
+	destroy_workqueue(dev_priv->gpu_error.hangcheck_wq);
+	destroy_workqueue(dev_priv->hotplug.dp_wq);
+	destroy_workqueue(dev_priv->wq);
+}
+
 /**
  * i915_driver_load - setup chip and create an initial config
  * @dev: DRM device
@@ -898,6 +946,10 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
 	mutex_init(&dev_priv->modeset_restore_lock);
 	mutex_init(&dev_priv->av_mutex);
 
+	ret = i915_workqueues_init(dev_priv);
+	if (ret < 0)
+		goto out_free_priv;
+
 	intel_pm_setup(dev);
 
 	intel_runtime_pm_get(dev_priv);
@@ -992,41 +1044,6 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
 	dev_priv->gtt.mtrr = arch_phys_wc_add(dev_priv->gtt.mappable_base,
 					      aperture_size);
 
-	/* The i915 workqueue is primarily used for batched retirement of
-	 * requests (and thus managing bo) once the task has been completed
-	 * by the GPU. i915_gem_retire_requests() is called directly when we
-	 * need high-priority retirement, such as waiting for an explicit
-	 * bo.
-	 *
-	 * It is also used for periodic low-priority events, such as
-	 * idle-timers and recording error state.
-	 *
-	 * All tasks on the workqueue are expected to acquire the dev mutex
-	 * so there is no point in running more than one instance of the
-	 * workqueue at any time.  Use an ordered one.
-	 */
-	dev_priv->wq = alloc_ordered_workqueue("i915", 0);
-	if (dev_priv->wq == NULL) {
-		DRM_ERROR("Failed to create our workqueue.\n");
-		ret = -ENOMEM;
-		goto out_mtrrfree;
-	}
-
-	dev_priv->hotplug.dp_wq = alloc_ordered_workqueue("i915-dp", 0);
-	if (dev_priv->hotplug.dp_wq == NULL) {
-		DRM_ERROR("Failed to create our dp workqueue.\n");
-		ret = -ENOMEM;
-		goto out_freewq;
-	}
-
-	dev_priv->gpu_error.hangcheck_wq =
-		alloc_ordered_workqueue("i915-hangcheck", 0);
-	if (dev_priv->gpu_error.hangcheck_wq == NULL) {
-		DRM_ERROR("Failed to create our hangcheck workqueue.\n");
-		ret = -ENOMEM;
-		goto out_freedpwq;
-	}
-
 	intel_irq_init(dev_priv);
 	intel_uncore_sanitize(dev);
 
@@ -1106,12 +1123,6 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
 
 	intel_teardown_mchbar(dev);
 	pm_qos_remove_request(&dev_priv->pm_qos);
-	destroy_workqueue(dev_priv->gpu_error.hangcheck_wq);
-out_freedpwq:
-	destroy_workqueue(dev_priv->hotplug.dp_wq);
-out_freewq:
-	destroy_workqueue(dev_priv->wq);
-out_mtrrfree:
 	arch_phys_wc_del(dev_priv->gtt.mtrr);
 	io_mapping_free(dev_priv->gtt.mappable);
 out_gtt:
@@ -1124,8 +1135,10 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
 	i915_gem_load_cleanup(dev);
 out_runtime_pm_put:
 	intel_runtime_pm_put(dev_priv);
-
+	i915_workqueues_cleanup(dev_priv);
+out_free_priv:
 	kfree(dev_priv);
+
 	return ret;
 }
 
@@ -1202,9 +1215,6 @@ int i915_driver_unload(struct drm_device *dev)
 
 	intel_teardown_mchbar(dev);
 
-	destroy_workqueue(dev_priv->hotplug.dp_wq);
-	destroy_workqueue(dev_priv->wq);
-	destroy_workqueue(dev_priv->gpu_error.hangcheck_wq);
 	pm_qos_remove_request(&dev_priv->pm_qos);
 
 	i915_global_gtt_cleanup(dev);
@@ -1215,6 +1225,7 @@ int i915_driver_unload(struct drm_device *dev)
 
 	i915_gem_load_cleanup(dev);
 	pci_dev_put(dev_priv->bridge_dev);
+	i915_workqueues_cleanup(dev_priv);
 	kfree(dev_priv);
 
 	return 0;