drm/i915: initialize the context idr unconditionally

It doesn't hurt and it at least prevents us from OOPSing left and
right at quite a few places. This also allows us to simplify the code
a bit by folding the only line of context_open into the callsite.

We obviuosly also need to run the cleanup code unconditionally, too.
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Signed-Off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_dma.c

@@ -1759,7 +1759,7 @@ int i915_driver_open(struct drm_device *dev, struct drm_file *file)
 	spin_lock_init(&file_priv->mm.lock);
 	INIT_LIST_HEAD(&file_priv->mm.request_list);
 
-	i915_gem_context_open(dev, file);
+	idr_init(&file_priv->context_idr);
 
 	return 0;
 }

drivers/gpu/drm/i915/i915_drv.h

@@ -1383,7 +1383,6 @@ struct dma_buf *i915_gem_prime_export(struct drm_device *dev,
 /* i915_gem_context.c */
 void i915_gem_context_init(struct drm_device *dev);
 void i915_gem_context_fini(struct drm_device *dev);
-void i915_gem_context_open(struct drm_device *dev, struct drm_file *file);
 void i915_gem_context_close(struct drm_device *dev, struct drm_file *file);
 int i915_switch_context(struct intel_ring_buffer *ring,
 			struct drm_file *file, int to_id);

drivers/gpu/drm/i915/i915_gem_context.c

@@ -287,17 +287,6 @@ void i915_gem_context_fini(struct drm_device *dev)
 	do_destroy(dev_priv->ring[RCS].default_context);
 }
 
-void i915_gem_context_open(struct drm_device *dev, struct drm_file *file)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	struct drm_i915_file_private *file_priv = file->driver_priv;
-
-	if (dev_priv->hw_contexts_disabled)
-		return;
-
-	idr_init(&file_priv->context_idr);
-}
-
 static int context_idr_cleanup(int id, void *p, void *data)
 {
 	struct drm_file *file = (struct drm_file *)data;
@@ -316,12 +305,8 @@ static int context_idr_cleanup(int id, void *p, void *data)
 
 void i915_gem_context_close(struct drm_device *dev, struct drm_file *file)
 {
-	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct drm_i915_file_private *file_priv = file->driver_priv;
 
-	if (dev_priv->hw_contexts_disabled)
-		return;
-
 	mutex_lock(&dev->struct_mutex);
 	idr_for_each(&file_priv->context_idr, context_idr_cleanup, file);
 	idr_destroy(&file_priv->context_idr);