drm/via: clean up reclaim_buffers

A few things
- kill reclaim_buffers, it's never ever called because via does not set
  DRIVER_HAVE_DMA
- inline the idlelock dance into the buffer reclaim logic and make it
  a simple preclose cleanup function
- directly call the the dma_quiescent function and kill the needless
  if check.

v2: Actually drop the idlelock when we take it. Reported by James
Simmons.

v3: Rebased onto latest drm-next.

v4: Fixup the refactor.

v5: More fixup the refactor - I've accidentally changed the check for
any master to checking whether the closing fd is the master.

v6: Don't forget to drop the idlelock in the early return path, too.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/via/via_drv.c

@@ -75,6 +75,7 @@ static struct drm_driver driver = {
 	.load = via_driver_load,
 	.unload = via_driver_unload,
 	.open = via_driver_open,
+	.preclose = via_reclaim_buffers_locked,
 	.postclose = via_driver_postclose,
 	.context_dtor = via_final_context,
 	.get_vblank_counter = via_get_vblank_counter,
@@ -85,9 +86,6 @@ static struct drm_driver driver = {
 	.irq_uninstall = via_driver_irq_uninstall,
 	.irq_handler = via_driver_irq_handler,
 	.dma_quiescent = via_driver_dma_quiescent,
-	.reclaim_buffers = drm_core_reclaim_buffers,
-	.reclaim_buffers_locked = NULL,
-	.reclaim_buffers_idlelocked = via_reclaim_buffers_locked,
 	.lastclose = via_lastclose,
 	.ioctls = via_ioctls,
 	.fops = &via_driver_fops,

drivers/gpu/drm/via/via_mm.c

@@ -215,14 +215,20 @@ void via_reclaim_buffers_locked(struct drm_device *dev,
 	struct via_file_private *file_priv = file->driver_priv;
 	struct via_memblock *entry, *next;
 
+	if (!(file->minor->master && file->master->lock.hw_lock))
+		return;
+
+	drm_idlelock_take(&file->master->lock);
+
 	mutex_lock(&dev->struct_mutex);
 	if (list_empty(&file_priv->obj_list)) {
 		mutex_unlock(&dev->struct_mutex);
+		drm_idlelock_release(&file->master->lock);
+
 		return;
 	}
 
-	if (dev->driver->dma_quiescent)
-		dev->driver->dma_quiescent(dev);
+	via_driver_dma_quiescent(dev);
 
 	list_for_each_entry_safe(entry, next, &file_priv->obj_list,
 				 owner_list) {
@@ -231,5 +237,8 @@ void via_reclaim_buffers_locked(struct drm_device *dev,
 		kfree(entry);
 	}
 	mutex_unlock(&dev->struct_mutex);
+
+	drm_idlelock_release(&file->master->lock);
+
 	return;
 }