drm/radeon: use system_wq instead of dev_priv->wq

With cmwq, there's no reason for radeon to use a dedicated workqueue.
Drop dev_priv->wq and use system_wq instead.

Because radeon_driver_irq_uninstall_kms() may be called from
unsleepable context, the work items can't be flushed from there.
Instead, init and flush from radeon_irq_kms_init/fini().

While at it, simplify canceling/flushing of rdev->pm.dynpm_idle_work.
Always initialize and sync cancel instead of being unnecessarily smart
about it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Alex Deucher <alexdeucher@gmail.com>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/evergreen.c

@@ -2756,7 +2756,7 @@ int evergreen_irq_process(struct radeon_device *rdev)
 	if (wptr != rdev->ih.wptr)
 		goto restart_ih;
 	if (queue_hotplug)
-		queue_work(rdev->wq, &rdev->hotplug_work);
+		schedule_work(&rdev->hotplug_work);
 	rdev->ih.rptr = rptr;
 	WREG32(IH_RB_RPTR, rdev->ih.rptr);
 	spin_unlock_irqrestore(&rdev->ih.lock, flags);

drivers/gpu/drm/radeon/r100.c

@@ -682,7 +682,7 @@ int r100_irq_process(struct radeon_device *rdev)
 	/* reset gui idle ack.  the status bit is broken */
 	rdev->irq.gui_idle_acked = false;
 	if (queue_hotplug)
-		queue_work(rdev->wq, &rdev->hotplug_work);
+		schedule_work(&rdev->hotplug_work);
 	if (rdev->msi_enabled) {
 		switch (rdev->family) {
 		case CHIP_RS400:

drivers/gpu/drm/radeon/r600.c

@@ -3442,7 +3442,7 @@ int r600_irq_process(struct radeon_device *rdev)
 	if (wptr != rdev->ih.wptr)
 		goto restart_ih;
 	if (queue_hotplug)
-		queue_work(rdev->wq, &rdev->hotplug_work);
+		schedule_work(&rdev->hotplug_work);
 	rdev->ih.rptr = rptr;
 	WREG32(IH_RB_RPTR, rdev->ih.rptr);
 	spin_unlock_irqrestore(&rdev->ih.lock, flags);

drivers/gpu/drm/radeon/radeon.h

@@ -1152,7 +1152,6 @@ struct radeon_device {
 	struct r700_vram_scratch vram_scratch;
 	int msi_enabled; /* msi enabled */
 	struct r600_ih ih; /* r6/700 interrupt ring */
-	struct workqueue_struct *wq;
 	struct work_struct hotplug_work;
 	int num_crtc; /* number of crtcs */
 	struct mutex dc_hw_i2c_mutex; /* display controller hw i2c mutex */

drivers/gpu/drm/radeon/radeon_device.c

@@ -710,11 +710,6 @@ int radeon_device_init(struct radeon_device *rdev,
 	init_waitqueue_head(&rdev->irq.vblank_queue);
 	init_waitqueue_head(&rdev->irq.idle_queue);
 
-	/* setup workqueue */
-	rdev->wq = create_workqueue("radeon");
-	if (rdev->wq == NULL)
-		return -ENOMEM;
-
 	/* Set asic functions */
 	r = radeon_asic_init(rdev);
 	if (r)
@@ -813,7 +808,6 @@ void radeon_device_fini(struct radeon_device *rdev)
 	/* evict vram memory */
 	radeon_bo_evict_vram(rdev);
 	radeon_fini(rdev);
-	destroy_workqueue(rdev->wq);
 	vga_switcheroo_unregister_client(rdev->pdev);
 	vga_client_register(rdev->pdev, NULL, NULL, NULL);
 	if (rdev->rio_mem)

drivers/gpu/drm/radeon/radeon_irq_kms.c

@@ -64,8 +64,6 @@ void radeon_driver_irq_preinstall_kms(struct drm_device *dev)
 	struct radeon_device *rdev = dev->dev_private;
 	unsigned i;
 
-	INIT_WORK(&rdev->hotplug_work, radeon_hotplug_work_func);
-
 	/* Disable *all* interrupts */
 	rdev->irq.sw_int = false;
 	rdev->irq.gui_idle = false;
@@ -114,6 +112,8 @@ int radeon_irq_kms_init(struct radeon_device *rdev)
 {
 	int r = 0;
 
+	INIT_WORK(&rdev->hotplug_work, radeon_hotplug_work_func);
+
 	spin_lock_init(&rdev->irq.sw_lock);
 	r = drm_vblank_init(rdev->ddev, rdev->num_crtc);
 	if (r) {
@@ -152,6 +152,7 @@ void radeon_irq_kms_fini(struct radeon_device *rdev)
 		if (rdev->msi_enabled)
 			pci_disable_msi(rdev->pdev);
 	}
+	flush_work_sync(&rdev->hotplug_work);
 }
 
 void radeon_irq_kms_sw_irq_get(struct radeon_device *rdev)

drivers/gpu/drm/radeon/radeon_pm.c

@@ -405,20 +405,13 @@ static ssize_t radeon_set_pm_method(struct device *dev,
 		rdev->pm.dynpm_planned_action = DYNPM_ACTION_DEFAULT;
 		mutex_unlock(&rdev->pm.mutex);
 	} else if (strncmp("profile", buf, strlen("profile")) == 0) {
-		bool flush_wq = false;
-
 		mutex_lock(&rdev->pm.mutex);
-		if (rdev->pm.pm_method == PM_METHOD_DYNPM) {
-			cancel_delayed_work(&rdev->pm.dynpm_idle_work);
-			flush_wq = true;
-		}
 		/* disable dynpm */
 		rdev->pm.dynpm_state = DYNPM_STATE_DISABLED;
 		rdev->pm.dynpm_planned_action = DYNPM_ACTION_NONE;
 		rdev->pm.pm_method = PM_METHOD_PROFILE;
 		mutex_unlock(&rdev->pm.mutex);
-		if (flush_wq)
-			flush_workqueue(rdev->wq);
+		cancel_delayed_work_sync(&rdev->pm.dynpm_idle_work);
 	} else {
 		DRM_ERROR("invalid power method!\n");
 		goto fail;
@@ -524,18 +517,14 @@ static void radeon_hwmon_fini(struct radeon_device *rdev)
 
 void radeon_pm_suspend(struct radeon_device *rdev)
 {
-	bool flush_wq = false;
-
 	mutex_lock(&rdev->pm.mutex);
 	if (rdev->pm.pm_method == PM_METHOD_DYNPM) {
-		cancel_delayed_work(&rdev->pm.dynpm_idle_work);
 		if (rdev->pm.dynpm_state == DYNPM_STATE_ACTIVE)
 			rdev->pm.dynpm_state = DYNPM_STATE_SUSPENDED;
-		flush_wq = true;
 	}
 	mutex_unlock(&rdev->pm.mutex);
-	if (flush_wq)
-		flush_workqueue(rdev->wq);
+
+	cancel_delayed_work_sync(&rdev->pm.dynpm_idle_work);
 }
 
 void radeon_pm_resume(struct radeon_device *rdev)
@@ -550,7 +539,7 @@ void radeon_pm_resume(struct radeon_device *rdev)
 	if (rdev->pm.pm_method == PM_METHOD_DYNPM
 	    && rdev->pm.dynpm_state == DYNPM_STATE_SUSPENDED) {
 		rdev->pm.dynpm_state = DYNPM_STATE_ACTIVE;
-		queue_delayed_work(rdev->wq, &rdev->pm.dynpm_idle_work,
+		schedule_delayed_work(&rdev->pm.dynpm_idle_work,
 				      msecs_to_jiffies(RADEON_IDLE_LOOP_MS));
 	}
 	mutex_unlock(&rdev->pm.mutex);
@@ -585,6 +574,9 @@ int radeon_pm_init(struct radeon_device *rdev)
 	ret = radeon_hwmon_init(rdev);
 	if (ret)
 		return ret;
+
+	INIT_DELAYED_WORK(&rdev->pm.dynpm_idle_work, radeon_dynpm_idle_work_handler);
+
 	if (rdev->pm.num_power_states > 1) {
 		/* where's the best place to put these? */
 		ret = device_create_file(rdev->dev, &dev_attr_power_profile);
@@ -598,8 +590,6 @@ int radeon_pm_init(struct radeon_device *rdev)
 		rdev->acpi_nb.notifier_call = radeon_acpi_event;
 		register_acpi_notifier(&rdev->acpi_nb);
 #endif
-		INIT_DELAYED_WORK(&rdev->pm.dynpm_idle_work, radeon_dynpm_idle_work_handler);
-
 		if (radeon_debugfs_pm_init(rdev)) {
 			DRM_ERROR("Failed to register debugfs file for PM!\n");
 		}
@@ -613,25 +603,20 @@ int radeon_pm_init(struct radeon_device *rdev)
 void radeon_pm_fini(struct radeon_device *rdev)
 {
 	if (rdev->pm.num_power_states > 1) {
-		bool flush_wq = false;
-
 		mutex_lock(&rdev->pm.mutex);
 		if (rdev->pm.pm_method == PM_METHOD_PROFILE) {
 			rdev->pm.profile = PM_PROFILE_DEFAULT;
 			radeon_pm_update_profile(rdev);
 			radeon_pm_set_clocks(rdev);
 		} else if (rdev->pm.pm_method == PM_METHOD_DYNPM) {
-			/* cancel work */
-			cancel_delayed_work(&rdev->pm.dynpm_idle_work);
-			flush_wq = true;
 			/* reset default clocks */
 			rdev->pm.dynpm_state = DYNPM_STATE_DISABLED;
 			rdev->pm.dynpm_planned_action = DYNPM_ACTION_DEFAULT;
 			radeon_pm_set_clocks(rdev);
 		}
 		mutex_unlock(&rdev->pm.mutex);
-		if (flush_wq)
-			flush_workqueue(rdev->wq);
+
+		cancel_delayed_work_sync(&rdev->pm.dynpm_idle_work);
 
 		device_remove_file(rdev->dev, &dev_attr_power_profile);
 		device_remove_file(rdev->dev, &dev_attr_power_method);
@@ -690,11 +675,11 @@ void radeon_pm_compute_clocks(struct radeon_device *rdev)
 					radeon_pm_get_dynpm_state(rdev);
 					radeon_pm_set_clocks(rdev);
 
-					queue_delayed_work(rdev->wq, &rdev->pm.dynpm_idle_work,
+					schedule_delayed_work(&rdev->pm.dynpm_idle_work,
 							      msecs_to_jiffies(RADEON_IDLE_LOOP_MS));
 				} else if (rdev->pm.dynpm_state == DYNPM_STATE_PAUSED) {
 					rdev->pm.dynpm_state = DYNPM_STATE_ACTIVE;
-					queue_delayed_work(rdev->wq, &rdev->pm.dynpm_idle_work,
+					schedule_delayed_work(&rdev->pm.dynpm_idle_work,
 							      msecs_to_jiffies(RADEON_IDLE_LOOP_MS));
 					DRM_DEBUG_DRIVER("radeon: dynamic power management activated\n");
 				}
@@ -800,7 +785,7 @@ static void radeon_dynpm_idle_work_handler(struct work_struct *work)
 			radeon_pm_set_clocks(rdev);
 		}
 
-		queue_delayed_work(rdev->wq, &rdev->pm.dynpm_idle_work,
+		schedule_delayed_work(&rdev->pm.dynpm_idle_work,
 				      msecs_to_jiffies(RADEON_IDLE_LOOP_MS));
 	}
 	mutex_unlock(&rdev->pm.mutex);

drivers/gpu/drm/radeon/rs600.c

@@ -692,7 +692,7 @@ int rs600_irq_process(struct radeon_device *rdev)
 	/* reset gui idle ack.  the status bit is broken */
 	rdev->irq.gui_idle_acked = false;
 	if (queue_hotplug)
-		queue_work(rdev->wq, &rdev->hotplug_work);
+		schedule_work(&rdev->hotplug_work);
 	if (rdev->msi_enabled) {
 		switch (rdev->family) {
 		case CHIP_RS600: