drm: Create drm_send_event helpers

Use them in the core vblank code and exynos/vmwgfx drivers.

Note that the difference between wake_up_all and _interruptible in
vmwgfx doesn't matter since the only waiter is the core code in
drm_fops.c. And that is interruptible.

v2: Adjust existing kerneldoc too.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com> (v1)
Acked-by: Daniel Stone <daniels@collabora.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Cc: Inki Dae <inki.dae@samsung.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452548477-15905-6-git-send-email-daniel.vetter@ffwll.ch
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
[danvet: Squash in compile fixup, spotted by 0-day.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/exynos/exynos_drm_g2d.c b/drivers/gpu/drm/exynos/exynos_drm_g2d.c
index 82e7f95..9936981 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_g2d.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_g2d.c
@@ -880,7 +880,6 @@
 	struct g2d_runqueue_node *runqueue_node = g2d->runqueue_node;
 	struct drm_exynos_pending_g2d_event *e;
 	struct timeval now;
-	unsigned long flags;
 
 	if (list_empty(&runqueue_node->event_list))
 		return;
@@ -893,10 +892,7 @@
 	e->event.tv_usec = now.tv_usec;
 	e->event.cmdlist_no = cmdlist_no;
 
-	spin_lock_irqsave(&drm_dev->event_lock, flags);
-	list_move_tail(&e->base.link, &e->base.file_priv->event_list);
-	wake_up_interruptible(&e->base.file_priv->event_wait);
-	spin_unlock_irqrestore(&drm_dev->event_lock, flags);
+	drm_send_event(drm_dev, &e->base);
 }
 
 static irqreturn_t g2d_irq_handler(int irq, void *dev_id)