drm/nouveau/core: convert event handler apis to split create/enable semantics

This is a necessary step towards being able to work with the insane locking
requirements of the DRM core's vblank routines, and a nice cleanup as a
side-effect.

This is similar in spirit to the interfaces that Peter Hurley arrived at
with his nouveau_event rcu conversion series.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/core/core/event.c

@@ -37,39 +37,82 @@ nouveau_event_put_locked(struct nouveau_event *event, int index,
 }
 
 void
-nouveau_event_put(struct nouveau_event *event, int index,
-		  struct nouveau_eventh *handler)
+nouveau_event_put(struct nouveau_eventh *handler)
 {
+	struct nouveau_event *event = handler->event;
 	unsigned long flags;
-
-	if (index >= event->index_nr)
-		return;
-
 	spin_lock_irqsave(&event->lock, flags);
-	nouveau_event_put_locked(event, index, handler);
+	nouveau_event_put_locked(handler->event, handler->index, handler);
 	spin_unlock_irqrestore(&event->lock, flags);
 }
 
 void
-nouveau_event_get(struct nouveau_event *event, int index,
-		  struct nouveau_eventh *handler)
+nouveau_event_get(struct nouveau_eventh *handler)
 {
+	struct nouveau_event *event = handler->event;
 	unsigned long flags;
 
-	if (index >= event->index_nr)
-		return;
-
 	spin_lock_irqsave(&event->lock, flags);
 	if (!__test_and_set_bit(NVKM_EVENT_ENABLE, &handler->flags)) {
-		list_add(&handler->head, &event->index[index].list);
-		if (!event->index[index].refs++) {
+		list_add(&handler->head, &event->index[handler->index].list);
+		if (!event->index[handler->index].refs++) {
 			if (event->enable)
-				event->enable(event, index);
+				event->enable(event, handler->index);
 		}
 	}
 	spin_unlock_irqrestore(&event->lock, flags);
 }
 
+static void
+nouveau_event_fini(struct nouveau_eventh *handler)
+{
+	nouveau_event_put(handler);
+}
+
+static int
+nouveau_event_init(struct nouveau_event *event, int index,
+		   int (*func)(void *, int), void *priv,
+		   struct nouveau_eventh *handler)
+{
+	if (index >= event->index_nr)
+		return -EINVAL;
+	handler->event = event;
+	handler->flags = 0;
+	handler->index = index;
+	handler->func = func;
+	handler->priv = priv;
+	return 0;
+}
+
+int
+nouveau_event_new(struct nouveau_event *event, int index,
+		  int (*func)(void *, int), void *priv,
+		  struct nouveau_eventh **phandler)
+{
+	struct nouveau_eventh *handler;
+	int ret = -ENOMEM;
+
+	handler = *phandler = kmalloc(sizeof(*handler), GFP_KERNEL);
+	if (handler) {
+		ret = nouveau_event_init(event, index, func, priv, handler);
+		if (ret)
+			kfree(handler);
+	}
+
+	return ret;
+}
+
+void
+nouveau_event_ref(struct nouveau_eventh *handler, struct nouveau_eventh **ref)
+{
+	BUG_ON(handler != NULL);
+	if (*ref) {
+		nouveau_event_fini(*ref);
+		kfree(*ref);
+	}
+	*ref = handler;
+}
+
 void
 nouveau_event_trigger(struct nouveau_event *event, int index)
 {
@@ -81,7 +124,7 @@ nouveau_event_trigger(struct nouveau_event *event, int index)
 
 	spin_lock_irqsave(&event->lock, flags);
 	list_for_each_entry_safe(handler, temp, &event->index[index].list, head) {
-		if (handler->func(handler, index) == NVKM_EVENT_DROP) {
+		if (handler->func(handler->priv, index) == NVKM_EVENT_DROP) {
 			nouveau_event_put_locked(event, index, handler);
 		}
 	}

drivers/gpu/drm/nouveau/core/engine/software/nv50.c

@@ -71,7 +71,7 @@ nv50_software_mthd_vblsem_offset(struct nouveau_object *object, u32 mthd,
 	return 0;
 }
 
-static int
+int
 nv50_software_mthd_vblsem_value(struct nouveau_object *object, u32 mthd,
 				void *args, u32 size)
 {
@@ -80,21 +80,20 @@ nv50_software_mthd_vblsem_value(struct nouveau_object *object, u32 mthd,
 	return 0;
 }
 
-static int
+int
 nv50_software_mthd_vblsem_release(struct nouveau_object *object, u32 mthd,
 				  void *args, u32 size)
 {
 	struct nv50_software_chan *chan = (void *)nv_engctx(object->parent);
-	struct nouveau_disp *disp = nouveau_disp(object);
-	u32 crtc = *(u32 *)args;
-	if (crtc > 1)
+	u32 head = *(u32 *)args;
+	if (head >= chan->vblank.nr_event)
 		return -EINVAL;
 
-	nouveau_event_get(disp->vblank, crtc, &chan->vblank.event);
+	nouveau_event_get(chan->vblank.event[head]);
 	return 0;
 }
 
-static int
+int
 nv50_software_mthd_flip(struct nouveau_object *object, u32 mthd,
 			void *args, u32 size)
 {
@@ -125,10 +124,9 @@ nv50_software_sclass[] = {
  ******************************************************************************/
 
 static int
-nv50_software_vblsem_release(struct nouveau_eventh *event, int head)
+nv50_software_vblsem_release(void *data, int head)
 {
-	struct nv50_software_chan *chan =
-		container_of(event, typeof(*chan), vblank.event);
+	struct nv50_software_chan *chan = data;
 	struct nv50_software_priv *priv = (void *)nv_object(chan)->engine;
 	struct nouveau_bar *bar = nouveau_bar(priv);
 
@@ -147,23 +145,51 @@ nv50_software_vblsem_release(struct nouveau_eventh *event, int head)
 	return NVKM_EVENT_DROP;
 }
 
+void
+nv50_software_context_dtor(struct nouveau_object *object)
+{
+	struct nv50_software_chan *chan = (void *)object;
+	int i;
+
+	if (chan->vblank.event) {
+		for (i = 0; i < chan->vblank.nr_event; i++)
+			nouveau_event_ref(NULL, &chan->vblank.event[i]);
+		kfree(chan->vblank.event);
+	}
+
+	nouveau_software_context_destroy(&chan->base);
+}
+
 int
 nv50_software_context_ctor(struct nouveau_object *parent,
 			   struct nouveau_object *engine,
 			   struct nouveau_oclass *oclass, void *data, u32 size,
 			   struct nouveau_object **pobject)
 {
+	struct nouveau_disp *pdisp = nouveau_disp(parent);
 	struct nv50_software_cclass *pclass = (void *)oclass;
 	struct nv50_software_chan *chan;
-	int ret;
+	int ret, i;
 
 	ret = nouveau_software_context_create(parent, engine, oclass, &chan);
 	*pobject = nv_object(chan);
 	if (ret)
 		return ret;
 
+	chan->vblank.nr_event = pdisp->vblank->index_nr;
+	chan->vblank.event = kzalloc(chan->vblank.nr_event *
+				     sizeof(*chan->vblank.event), GFP_KERNEL);
+	if (!chan->vblank.event)
+		return -ENOMEM;
+
+	for (i = 0; i < chan->vblank.nr_event; i++) {
+		ret = nouveau_event_new(pdisp->vblank, i, pclass->vblank,
+					chan, &chan->vblank.event[i]);
+		if (ret)
+			return ret;
+	}
+
 	chan->vblank.channel = nv_gpuobj(parent->parent)->addr >> 12;
-	chan->vblank.event.func = pclass->vblank;
 	return 0;
 }
 

drivers/gpu/drm/nouveau/core/engine/software/nv50.h

@@ -19,13 +19,14 @@ int  nv50_software_ctor(struct nouveau_object *, struct nouveau_object *,
 
 struct nv50_software_cclass {
 	struct nouveau_oclass base;
-	int (*vblank)(struct nouveau_eventh *, int);
+	int (*vblank)(void *, int);
 };
 
 struct nv50_software_chan {
 	struct nouveau_software_chan base;
 	struct {
-		struct nouveau_eventh event;
+		struct nouveau_eventh **event;
+		int nr_event;
 		u32 channel;
 		u32 ctxdma;
 		u64 offset;
@@ -37,5 +38,10 @@ int  nv50_software_context_ctor(struct nouveau_object *,
 				struct nouveau_object *,
 				struct nouveau_oclass *, void *, u32,
 				struct nouveau_object **);
+void nv50_software_context_dtor(struct nouveau_object *);
+
+int nv50_software_mthd_vblsem_value(struct nouveau_object *, u32, void *, u32);
+int nv50_software_mthd_vblsem_release(struct nouveau_object *, u32, void *, u32);
+int nv50_software_mthd_flip(struct nouveau_object *, u32, void *, u32);
 
 #endif

drivers/gpu/drm/nouveau/core/engine/software/nvc0.c

@@ -54,40 +54,6 @@ nvc0_software_mthd_vblsem_offset(struct nouveau_object *object, u32 mthd,
 	return 0;
 }
 
-static int
-nvc0_software_mthd_vblsem_value(struct nouveau_object *object, u32 mthd,
-				void *args, u32 size)
-{
-	struct nv50_software_chan *chan = (void *)nv_engctx(object->parent);
-	chan->vblank.value = *(u32 *)args;
-	return 0;
-}
-
-static int
-nvc0_software_mthd_vblsem_release(struct nouveau_object *object, u32 mthd,
-				  void *args, u32 size)
-{
-	struct nv50_software_chan *chan = (void *)nv_engctx(object->parent);
-	struct nouveau_disp *disp = nouveau_disp(object);
-	u32 crtc = *(u32 *)args;
-
-	if ((nv_device(object)->card_type < NV_E0 && crtc > 1) || crtc > 3)
-		return -EINVAL;
-
-	nouveau_event_get(disp->vblank, crtc, &chan->vblank.event);
-	return 0;
-}
-
-static int
-nvc0_software_mthd_flip(struct nouveau_object *object, u32 mthd,
-			void *args, u32 size)
-{
-	struct nv50_software_chan *chan = (void *)nv_engctx(object->parent);
-	if (chan->base.flip)
-		return chan->base.flip(chan->base.flip_data);
-	return -EINVAL;
-}
-
 static int
 nvc0_software_mthd_mp_control(struct nouveau_object *object, u32 mthd,
                               void *args, u32 size)
@@ -118,9 +84,9 @@ static struct nouveau_omthds
 nvc0_software_omthds[] = {
 	{ 0x0400, 0x0400, nvc0_software_mthd_vblsem_offset },
 	{ 0x0404, 0x0404, nvc0_software_mthd_vblsem_offset },
-	{ 0x0408, 0x0408, nvc0_software_mthd_vblsem_value },
-	{ 0x040c, 0x040c, nvc0_software_mthd_vblsem_release },
-	{ 0x0500, 0x0500, nvc0_software_mthd_flip },
+	{ 0x0408, 0x0408, nv50_software_mthd_vblsem_value },
+	{ 0x040c, 0x040c, nv50_software_mthd_vblsem_release },
+	{ 0x0500, 0x0500, nv50_software_mthd_flip },
 	{ 0x0600, 0x0600, nvc0_software_mthd_mp_control },
 	{ 0x0644, 0x0644, nvc0_software_mthd_mp_control },
 	{ 0x06ac, 0x06ac, nvc0_software_mthd_mp_control },
@@ -138,10 +104,9 @@ nvc0_software_sclass[] = {
  ******************************************************************************/
 
 static int
-nvc0_software_vblsem_release(struct nouveau_eventh *event, int head)
+nvc0_software_vblsem_release(void *data, int head)
 {
-	struct nv50_software_chan *chan =
-		container_of(event, typeof(*chan), vblank.event);
+	struct nv50_software_chan *chan = data;
 	struct nv50_software_priv *priv = (void *)nv_object(chan)->engine;
 	struct nouveau_bar *bar = nouveau_bar(priv);
 

drivers/gpu/drm/nouveau/core/include/core/event.h

@@ -9,10 +9,12 @@
 #define NVKM_EVENT_ENABLE 0
 
 struct nouveau_eventh {
+	struct nouveau_event *event;
 	struct list_head head;
 	unsigned long flags;
+	int index;
+	int (*func)(void *, int);
 	void *priv;
-	int (*func)(struct nouveau_eventh *, int index);
 };
 
 struct nouveau_event {
@@ -33,9 +35,11 @@ int  nouveau_event_create(int index_nr, struct nouveau_event **);
 void nouveau_event_destroy(struct nouveau_event **);
 void nouveau_event_trigger(struct nouveau_event *, int index);
 
-void nouveau_event_get(struct nouveau_event *, int index,
-		       struct nouveau_eventh *);
-void nouveau_event_put(struct nouveau_event *, int index,
-		       struct nouveau_eventh *);
+int  nouveau_event_new(struct nouveau_event *, int index,
+		       int (*func)(void *, int), void *,
+		       struct nouveau_eventh **);
+void nouveau_event_ref(struct nouveau_eventh *, struct nouveau_eventh **);
+void nouveau_event_get(struct nouveau_eventh *);
+void nouveau_event_put(struct nouveau_eventh *);
 
 #endif

drivers/gpu/drm/nouveau/nouveau_connector.c

@@ -100,6 +100,7 @@ static void
 nouveau_connector_destroy(struct drm_connector *connector)
 {
 	struct nouveau_connector *nv_connector = nouveau_connector(connector);
+	nouveau_event_ref(NULL, &nv_connector->hpd_func);
 	kfree(nv_connector->edid);
 	drm_sysfs_connector_remove(connector);
 	drm_connector_cleanup(connector);
@@ -932,10 +933,9 @@ nouveau_connector_hotplug_work(struct work_struct *work)
 }
 
 static int
-nouveau_connector_hotplug(struct nouveau_eventh *event, int index)
+nouveau_connector_hotplug(void *data, int index)
 {
-	struct nouveau_connector *nv_connector =
-		container_of(event, struct nouveau_connector, hpd_func);
+	struct nouveau_connector *nv_connector = data;
 	schedule_work(&nv_connector->hpd_work);
 	return NVKM_EVENT_KEEP;
 }
@@ -1007,10 +1007,16 @@ nouveau_connector_create(struct drm_device *dev, int index)
 
 		ret = gpio->find(gpio, 0, hpd[ffs((entry & 0x07033000) >> 12)],
 				 DCB_GPIO_UNUSED, &nv_connector->hpd);
-		nv_connector->hpd_func.func = nouveau_connector_hotplug;
 		if (ret)
 			nv_connector->hpd.func = DCB_GPIO_UNUSED;
 
+		if (nv_connector->hpd.func != DCB_GPIO_UNUSED) {
+			nouveau_event_new(gpio->events, nv_connector->hpd.line,
+					  nouveau_connector_hotplug,
+					  nv_connector,
+					 &nv_connector->hpd_func);
+		}
+
 		nv_connector->type = nv_connector->dcb[0];
 		if (drm_conntype_from_dcb(nv_connector->type) ==
 					  DRM_MODE_CONNECTOR_Unknown) {

drivers/gpu/drm/nouveau/nouveau_connector.h

@@ -69,7 +69,7 @@ struct nouveau_connector {
 
 	struct dcb_gpio_func hpd;
 	struct work_struct hpd_work;
-	struct nouveau_eventh hpd_func;
+	struct nouveau_eventh *hpd_func;
 
 	int dithering_mode;
 	int dithering_depth;

drivers/gpu/drm/nouveau/nouveau_display.c

@@ -38,12 +38,85 @@
 
 #include "nouveau_fence.h"
 
-#include <subdev/bios/gpio.h>
-#include <subdev/gpio.h>
 #include <engine/disp.h>
 
 #include <core/class.h>
 
+static int
+nouveau_display_vblank_handler(void *data, int head)
+{
+	struct nouveau_drm *drm = data;
+	drm_handle_vblank(drm->dev, head);
+	return NVKM_EVENT_KEEP;
+}
+
+int
+nouveau_display_vblank_enable(struct drm_device *dev, int head)
+{
+	struct nouveau_display *disp = nouveau_display(dev);
+	if (disp) {
+		nouveau_event_get(disp->vblank[head]);
+		return 0;
+	}
+	return -EIO;
+}
+
+void
+nouveau_display_vblank_disable(struct drm_device *dev, int head)
+{
+	struct nouveau_display *disp = nouveau_display(dev);
+	if (disp)
+		nouveau_event_put(disp->vblank[head]);
+}
+
+static void
+nouveau_display_vblank_fini(struct drm_device *dev)
+{
+	struct nouveau_display *disp = nouveau_display(dev);
+	int i;
+
+	if (disp->vblank) {
+		for (i = 0; i < dev->mode_config.num_crtc; i++)
+			nouveau_event_ref(NULL, &disp->vblank[i]);
+		kfree(disp->vblank);
+		disp->vblank = NULL;
+	}
+
+	drm_vblank_cleanup(dev);
+}
+
+static int
+nouveau_display_vblank_init(struct drm_device *dev)
+{
+	struct nouveau_display *disp = nouveau_display(dev);
+	struct nouveau_drm *drm = nouveau_drm(dev);
+	struct nouveau_disp *pdisp = nouveau_disp(drm->device);
+	int ret, i;
+
+	disp->vblank = kzalloc(dev->mode_config.num_crtc *
+			       sizeof(*disp->vblank), GFP_KERNEL);
+	if (!disp->vblank)
+		return -ENOMEM;
+
+	for (i = 0; i < dev->mode_config.num_crtc; i++) {
+		ret = nouveau_event_new(pdisp->vblank, i,
+					nouveau_display_vblank_handler,
+					drm, &disp->vblank[i]);
+		if (ret) {
+			nouveau_display_vblank_fini(dev);
+			return ret;
+		}
+	}
+
+	ret = drm_vblank_init(dev, dev->mode_config.num_crtc);
+	if (ret) {
+		nouveau_display_vblank_fini(dev);
+		return ret;
+	}
+
+	return 0;
+}
+
 static void
 nouveau_user_framebuffer_destroy(struct drm_framebuffer *drm_fb)
 {
@@ -227,9 +300,7 @@ static struct nouveau_drm_prop_enum_list dither_depth[] = {
 int
 nouveau_display_init(struct drm_device *dev)
 {
-	struct nouveau_drm *drm = nouveau_drm(dev);
 	struct nouveau_display *disp = nouveau_display(dev);
-	struct nouveau_gpio *gpio = nouveau_gpio(drm->device);
 	struct drm_connector *connector;
 	int ret;
 
@@ -243,10 +314,7 @@ nouveau_display_init(struct drm_device *dev)
 	/* enable hotplug interrupts */
 	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
 		struct nouveau_connector *conn = nouveau_connector(connector);
-		if (gpio && conn->hpd.func != DCB_GPIO_UNUSED) {
-			nouveau_event_get(gpio->events, conn->hpd.line,
-					 &conn->hpd_func);
-		}
+		if (conn->hpd_func) nouveau_event_get(conn->hpd_func);
 	}
 
 	return ret;
@@ -255,18 +323,13 @@ nouveau_display_init(struct drm_device *dev)
 void
 nouveau_display_fini(struct drm_device *dev)
 {
-	struct nouveau_drm *drm = nouveau_drm(dev);
 	struct nouveau_display *disp = nouveau_display(dev);
-	struct nouveau_gpio *gpio = nouveau_gpio(drm->device);
 	struct drm_connector *connector;
 
 	/* disable hotplug interrupts */
 	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
 		struct nouveau_connector *conn = nouveau_connector(connector);
-		if (gpio && conn->hpd.func != DCB_GPIO_UNUSED) {
-			nouveau_event_put(gpio->events, conn->hpd.line,
-					 &conn->hpd_func);
-		}
+		if (conn->hpd_func) nouveau_event_put(conn->hpd_func);
 	}
 
 	drm_kms_helper_poll_disable(dev);
@@ -352,7 +415,7 @@ nouveau_display_create(struct drm_device *dev)
 		goto disp_create_err;
 
 	if (dev->mode_config.num_crtc) {
-		ret = drm_vblank_init(dev, dev->mode_config.num_crtc);
+		ret = nouveau_display_vblank_init(dev);
 		if (ret)
 			goto vblank_err;
 	}
@@ -374,7 +437,7 @@ nouveau_display_destroy(struct drm_device *dev)
 	struct nouveau_display *disp = nouveau_display(dev);
 
 	nouveau_backlight_exit(dev);
-	drm_vblank_cleanup(dev);
+	nouveau_display_vblank_fini(dev);
 
 	drm_kms_helper_poll_fini(dev);
 	drm_mode_config_cleanup(dev);

drivers/gpu/drm/nouveau/nouveau_display.h

@@ -36,6 +36,8 @@ struct nouveau_display {
 	int  (*init)(struct drm_device *);
 	void (*fini)(struct drm_device *);
 
+	struct nouveau_eventh **vblank;
+
 	struct drm_property *dithering_mode;
 	struct drm_property *dithering_depth;
 	struct drm_property *underscan_property;
@@ -59,6 +61,8 @@ void nouveau_display_fini(struct drm_device *dev);
 int  nouveau_display_suspend(struct drm_device *dev);
 void nouveau_display_repin(struct drm_device *dev);
 void nouveau_display_resume(struct drm_device *dev);
+int  nouveau_display_vblank_enable(struct drm_device *, int);
+void nouveau_display_vblank_disable(struct drm_device *, int);
 
 int  nouveau_crtc_page_flip(struct drm_crtc *crtc, struct drm_framebuffer *fb,
 			    struct drm_pending_vblank_event *event,

drivers/gpu/drm/nouveau/nouveau_drm.c

@@ -78,37 +78,6 @@ module_param_named(runpm, nouveau_runtime_pm, int, 0400);
 
 static struct drm_driver driver;
 
-static int
-nouveau_drm_vblank_handler(struct nouveau_eventh *event, int head)
-{
-	struct nouveau_drm *drm =
-		container_of(event, struct nouveau_drm, vblank[head]);
-	drm_handle_vblank(drm->dev, head);
-	return NVKM_EVENT_KEEP;
-}
-
-static int
-nouveau_drm_vblank_enable(struct drm_device *dev, int head)
-{
-	struct nouveau_drm *drm = nouveau_drm(dev);
-	struct nouveau_disp *pdisp = nouveau_disp(drm->device);
-
-	if (WARN_ON_ONCE(head >= ARRAY_SIZE(drm->vblank)))
-		return -EIO;
-	drm->vblank[head].func = nouveau_drm_vblank_handler;
-	nouveau_event_get(pdisp->vblank, head, &drm->vblank[head]);
-	return 0;
-}
-
-static void
-nouveau_drm_vblank_disable(struct drm_device *dev, int head)
-{
-	struct nouveau_drm *drm = nouveau_drm(dev);
-	struct nouveau_disp *pdisp = nouveau_disp(drm->device);
-
-	nouveau_event_put(pdisp->vblank, head, &drm->vblank[head]);
-}
-
 static u64
 nouveau_name(struct pci_dev *pdev)
 {
@@ -812,8 +781,8 @@ driver = {
 #endif
 
 	.get_vblank_counter = drm_vblank_count,
-	.enable_vblank = nouveau_drm_vblank_enable,
-	.disable_vblank = nouveau_drm_vblank_disable,
+	.enable_vblank = nouveau_display_vblank_enable,
+	.disable_vblank = nouveau_display_vblank_disable,
 
 	.ioctls = nouveau_ioctls,
 	.num_ioctls = ARRAY_SIZE(nouveau_ioctls),

drivers/gpu/drm/nouveau/nouveau_drm.h

@@ -127,7 +127,6 @@ struct nouveau_drm {
 	struct nvbios vbios;
 	struct nouveau_display *display;
 	struct backlight_device *backlight;
-	struct nouveau_eventh vblank[4];
 
 	/* power management */
 	struct nouveau_pm *pm;

drivers/gpu/drm/nouveau/nouveau_fence.c

@@ -166,9 +166,9 @@ nouveau_fence_done(struct nouveau_fence *fence)
 }
 
 static int
-nouveau_fence_wait_uevent_handler(struct nouveau_eventh *handler, int index)
+nouveau_fence_wait_uevent_handler(void *data, int index)
 {
-	struct nouveau_fence_priv *priv = handler->priv;
+	struct nouveau_fence_priv *priv = data;
 	wake_up_all(&priv->waiting);
 	return NVKM_EVENT_KEEP;
 }
@@ -180,13 +180,16 @@ nouveau_fence_wait_uevent(struct nouveau_fence *fence, bool intr)
 	struct nouveau_channel *chan = fence->channel;
 	struct nouveau_fifo *pfifo = nouveau_fifo(chan->drm->device);
 	struct nouveau_fence_priv *priv = chan->drm->fence;
-	struct nouveau_eventh handler = {
-		.func = nouveau_fence_wait_uevent_handler,
-		.priv = priv,
-	};
+	struct nouveau_eventh *handler;
 	int ret = 0;
 
-	nouveau_event_get(pfifo->uevent, 0, &handler);
+	ret = nouveau_event_new(pfifo->uevent, 0,
+				nouveau_fence_wait_uevent_handler,
+				priv, &handler);
+	if (ret)
+		return ret;
+
+	nouveau_event_get(handler);
 
 	if (fence->timeout) {
 		unsigned long timeout = fence->timeout - jiffies;
@@ -218,7 +221,7 @@ nouveau_fence_wait_uevent(struct nouveau_fence *fence, bool intr)
 		}
 	}
 
-	nouveau_event_put(pfifo->uevent, 0, &handler);
+	nouveau_event_ref(NULL, &handler);
 	if (unlikely(ret < 0))
 		return ret;