drm/i915: add a dedicated workqueue inside drm_i915_private

In order to avoid flush_scheduled_work() usage, add a dedicated
workqueue in the drm_i915_private structure.  In this way, we don't
need to use the system queue anymore.

This change is mostly mechanical and based on Tetsuo's original
patch[1].

v6 by Jani:
- Also create unordered_wq for mock device

Link: https://patchwork.freedesktop.org/series/114608/ [1]
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/c816ebe17ef08d363981942a096a586a7658a65e.1686231190.git.jani.nikula@intel.com

Author: lucacoelho

drivers/gpu/drm/i915/display/intel_display.c

@@ -7180,11 +7180,12 @@ intel_atomic_commit_ready(struct i915_sw_fence *fence,
 		break;
 	case FENCE_FREE:
 		{
+			struct drm_i915_private *i915 = to_i915(state->base.dev);
 			struct intel_atomic_helper *helper =
-				&to_i915(state->base.dev)->display.atomic_helper;
+				&i915->display.atomic_helper;
 
 			if (llist_add(&state->freed, &helper->free_list))
-				schedule_work(&helper->free_work);
+				queue_work(i915->unordered_wq, &helper->free_work);
 			break;
 		}
 	}

drivers/gpu/drm/i915/display/intel_display_driver.c

@@ -442,7 +442,7 @@ void intel_display_driver_remove_noirq(struct drm_i915_private *i915)
 	intel_unregister_dsm_handler();
 
 	/* flush any delayed tasks or pending work */
-	flush_scheduled_work();
+	flush_workqueue(i915->unordered_wq);
 
 	intel_hdcp_component_fini(i915);
 

drivers/gpu/drm/i915/display/intel_dmc.c

@@ -1057,7 +1057,7 @@ void intel_dmc_init(struct drm_i915_private *i915)
 	i915->display.dmc.dmc = dmc;
 
 	drm_dbg_kms(&i915->drm, "Loading %s\n", dmc->fw_path);
-	schedule_work(&dmc->work);
+	queue_work(i915->unordered_wq, &dmc->work);
 
 	return;
 

drivers/gpu/drm/i915/display/intel_dp.c

@@ -5251,7 +5251,7 @@ static void intel_dp_oob_hotplug_event(struct drm_connector *connector)
 	spin_lock_irq(&i915->irq_lock);
 	i915->display.hotplug.event_bits |= BIT(encoder->hpd_pin);
 	spin_unlock_irq(&i915->irq_lock);
-	queue_delayed_work(system_wq, &i915->display.hotplug.hotplug_work, 0);
+	queue_delayed_work(i915->unordered_wq, &i915->display.hotplug.hotplug_work, 0);
 }
 
 static const struct drm_connector_funcs intel_dp_connector_funcs = {

drivers/gpu/drm/i915/display/intel_dp_link_training.c

@@ -1064,6 +1064,7 @@ static void intel_dp_schedule_fallback_link_training(struct intel_dp *intel_dp,
 						     const struct intel_crtc_state *crtc_state)
 {
 	struct intel_connector *intel_connector = intel_dp->attached_connector;
+	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
 
 	if (!intel_digital_port_connected(&dp_to_dig_port(intel_dp)->base)) {
 		lt_dbg(intel_dp, DP_PHY_DPRX, "Link Training failed on disconnected sink.\n");
@@ -1081,7 +1082,7 @@ static void intel_dp_schedule_fallback_link_training(struct intel_dp *intel_dp,
 	}
 
 	/* Schedule a Hotplug Uevent to userspace to start modeset */
-	schedule_work(&intel_connector->modeset_retry_work);
+	queue_work(i915->unordered_wq, &intel_connector->modeset_retry_work);
 }
 
 /* Perform the link training on all LTTPRs and the DPRX on a link. */

drivers/gpu/drm/i915/display/intel_drrs.c

@@ -111,7 +111,9 @@ static void intel_drrs_set_state(struct intel_crtc *crtc,
 
 static void intel_drrs_schedule_work(struct intel_crtc *crtc)
 {
-	mod_delayed_work(system_wq, &crtc->drrs.work, msecs_to_jiffies(1000));
+	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
+
+	mod_delayed_work(i915->unordered_wq, &crtc->drrs.work, msecs_to_jiffies(1000));
 }
 
 static unsigned int intel_drrs_frontbuffer_bits(const struct intel_crtc_state *crtc_state)

drivers/gpu/drm/i915/display/intel_fbc.c

@@ -1600,7 +1600,7 @@ static void __intel_fbc_handle_fifo_underrun_irq(struct intel_fbc *fbc)
 	if (READ_ONCE(fbc->underrun_detected))
 		return;
 
-	schedule_work(&fbc->underrun_work);
+	queue_work(fbc->i915->unordered_wq, &fbc->underrun_work);
 }
 
 /**

drivers/gpu/drm/i915/display/intel_fbdev.c

@@ -694,7 +694,8 @@ void intel_fbdev_set_suspend(struct drm_device *dev, int state, bool synchronous
 			/* Don't block our own workqueue as this can
 			 * be run in parallel with other i915.ko tasks.
 			 */
-			schedule_work(&dev_priv->display.fbdev.suspend_work);
+			queue_work(dev_priv->unordered_wq,
+				   &dev_priv->display.fbdev.suspend_work);
 			return;
 		}
 	}

drivers/gpu/drm/i915/display/intel_hdcp.c

@@ -983,6 +983,7 @@ static void intel_hdcp_update_value(struct intel_connector *connector,
 	struct drm_device *dev = connector->base.dev;
 	struct intel_digital_port *dig_port = intel_attached_dig_port(connector);
 	struct intel_hdcp *hdcp = &connector->hdcp;
+	struct drm_i915_private *i915 = to_i915(connector->base.dev);
 
 	drm_WARN_ON(connector->base.dev, !mutex_is_locked(&hdcp->mutex));
 
@@ -1001,7 +1002,7 @@ static void intel_hdcp_update_value(struct intel_connector *connector,
 	hdcp->value = value;
 	if (update_property) {
 		drm_connector_get(&connector->base);
-		schedule_work(&hdcp->prop_work);
+		queue_work(i915->unordered_wq, &hdcp->prop_work);
 	}
 }
 
@@ -2090,16 +2091,17 @@ static void intel_hdcp_check_work(struct work_struct *work)
 					       struct intel_hdcp,
 					       check_work);
 	struct intel_connector *connector = intel_hdcp_to_connector(hdcp);
+	struct drm_i915_private *i915 = to_i915(connector->base.dev);
 
 	if (drm_connector_is_unregistered(&connector->base))
 		return;
 
 	if (!intel_hdcp2_check_link(connector))
-		schedule_delayed_work(&hdcp->check_work,
-				      DRM_HDCP2_CHECK_PERIOD_MS);
+		queue_delayed_work(i915->unordered_wq, &hdcp->check_work,
+				   DRM_HDCP2_CHECK_PERIOD_MS);
 	else if (!intel_hdcp_check_link(connector))
-		schedule_delayed_work(&hdcp->check_work,
-				      DRM_HDCP_CHECK_PERIOD_MS);
+		queue_delayed_work(i915->unordered_wq, &hdcp->check_work,
+				   DRM_HDCP_CHECK_PERIOD_MS);
 }
 
 static int i915_hdcp_component_bind(struct device *i915_kdev,
@@ -2398,7 +2400,8 @@ int intel_hdcp_enable(struct intel_atomic_state *state,
 	}
 
 	if (!ret) {
-		schedule_delayed_work(&hdcp->check_work, check_link_interval);
+		queue_delayed_work(i915->unordered_wq, &hdcp->check_work,
+				   check_link_interval);
 		intel_hdcp_update_value(connector,
 					DRM_MODE_CONTENT_PROTECTION_ENABLED,
 					true);
@@ -2447,6 +2450,7 @@ void intel_hdcp_update_pipe(struct intel_atomic_state *state,
 				to_intel_connector(conn_state->connector);
 	struct intel_hdcp *hdcp = &connector->hdcp;
 	bool content_protection_type_changed, desired_and_not_enabled = false;
+	struct drm_i915_private *i915 = to_i915(connector->base.dev);
 
 	if (!connector->hdcp.shim)
 		return;
@@ -2473,7 +2477,7 @@ void intel_hdcp_update_pipe(struct intel_atomic_state *state,
 		mutex_lock(&hdcp->mutex);
 		hdcp->value = DRM_MODE_CONTENT_PROTECTION_DESIRED;
 		drm_connector_get(&connector->base);
-		schedule_work(&hdcp->prop_work);
+		queue_work(i915->unordered_wq, &hdcp->prop_work);
 		mutex_unlock(&hdcp->mutex);
 	}
 
@@ -2490,7 +2494,7 @@ void intel_hdcp_update_pipe(struct intel_atomic_state *state,
 		 */
 		if (!desired_and_not_enabled && !content_protection_type_changed) {
 			drm_connector_get(&connector->base);
-			schedule_work(&hdcp->prop_work);
+			queue_work(i915->unordered_wq, &hdcp->prop_work);
 		}
 	}
 
@@ -2602,12 +2606,13 @@ void intel_hdcp_atomic_check(struct drm_connector *connector,
 void intel_hdcp_handle_cp_irq(struct intel_connector *connector)
 {
 	struct intel_hdcp *hdcp = &connector->hdcp;
+	struct drm_i915_private *i915 = to_i915(connector->base.dev);
 
 	if (!hdcp->shim)
 		return;
 
 	atomic_inc(&connector->hdcp.cp_irq_count);
 	wake_up_all(&connector->hdcp.cp_irq_queue);
 
-	schedule_delayed_work(&hdcp->check_work, 0);
+	queue_delayed_work(i915->unordered_wq, &hdcp->check_work, 0);
 }

drivers/gpu/drm/i915/display/intel_hotplug.c

@@ -212,7 +212,8 @@ intel_hpd_irq_storm_switch_to_polling(struct drm_i915_private *dev_priv)
 	/* Enable polling and queue hotplug re-enabling. */
 	if (hpd_disabled) {
 		drm_kms_helper_poll_enable(&dev_priv->drm);
-		mod_delayed_work(system_wq, &dev_priv->display.hotplug.reenable_work,
+		mod_delayed_work(dev_priv->unordered_wq,
+				 &dev_priv->display.hotplug.reenable_work,
 				 msecs_to_jiffies(HPD_STORM_REENABLE_DELAY));
 	}
 }
@@ -339,7 +340,8 @@ static void i915_digport_work_func(struct work_struct *work)
 		spin_lock_irq(&dev_priv->irq_lock);
 		dev_priv->display.hotplug.event_bits |= old_bits;
 		spin_unlock_irq(&dev_priv->irq_lock);
-		queue_delayed_work(system_wq, &dev_priv->display.hotplug.hotplug_work, 0);
+		queue_delayed_work(dev_priv->unordered_wq,
+				   &dev_priv->display.hotplug.hotplug_work, 0);
 	}
 }
 
@@ -446,7 +448,8 @@ static void i915_hotplug_work_func(struct work_struct *work)
 		dev_priv->display.hotplug.retry_bits |= retry;
 		spin_unlock_irq(&dev_priv->irq_lock);
 
-		mod_delayed_work(system_wq, &dev_priv->display.hotplug.hotplug_work,
+		mod_delayed_work(dev_priv->unordered_wq,
+				 &dev_priv->display.hotplug.hotplug_work,
 				 msecs_to_jiffies(HPD_RETRY_DELAY));
 	}
 }
@@ -577,7 +580,8 @@ void intel_hpd_irq_handler(struct drm_i915_private *dev_priv,
 	if (queue_dig)
 		queue_work(dev_priv->display.hotplug.dp_wq, &dev_priv->display.hotplug.dig_port_work);
 	if (queue_hp)
-		queue_delayed_work(system_wq, &dev_priv->display.hotplug.hotplug_work, 0);
+		queue_delayed_work(dev_priv->unordered_wq,
+				   &dev_priv->display.hotplug.hotplug_work, 0);
 }
 
 /**
@@ -687,7 +691,8 @@ void intel_hpd_poll_enable(struct drm_i915_private *dev_priv)
 	 * As well, there's no issue if we race here since we always reschedule
 	 * this worker anyway
 	 */
-	schedule_work(&dev_priv->display.hotplug.poll_init_work);
+	queue_work(dev_priv->unordered_wq,
+		   &dev_priv->display.hotplug.poll_init_work);
 }
 
 /**
@@ -715,7 +720,8 @@ void intel_hpd_poll_disable(struct drm_i915_private *dev_priv)
 		return;
 
 	WRITE_ONCE(dev_priv->display.hotplug.poll_enabled, false);
-	schedule_work(&dev_priv->display.hotplug.poll_init_work);
+	queue_work(dev_priv->unordered_wq,
+		   &dev_priv->display.hotplug.poll_init_work);
 }
 
 void intel_hpd_init_early(struct drm_i915_private *i915)