drm/i915: Avoid allocation for execbuffer object list

Besides the minimal improvement in reducing the execbuffer overhead, the
real benefit is clarifying a few routines.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/i915_drv.h

@@ -712,8 +712,8 @@ struct drm_i915_gem_object {
 	struct list_head mm_list;
 	/** This object's place on GPU write list */
 	struct list_head gpu_write_list;
-	/** This object's place on eviction list */
-	struct list_head evict_list;
+	/** This object's place in the batchbuffer or on the eviction list */
+	struct list_head exec_list;
 
 	/**
 	 * This is set if the object is on the active or flushing lists
@@ -737,12 +737,6 @@ struct drm_i915_gem_object {
 	 */
 	signed int fence_reg : 5;
 
-	/**
-	 * Used for checking the object doesn't appear more than once
-	 * in an execbuffer object list.
-	 */
-	unsigned int in_execbuffer : 1;
-
 	/**
 	 * Advice: are the backing pages purgeable?
 	 */

drivers/gpu/drm/i915/i915_gem.c

@@ -3399,6 +3399,7 @@ struct drm_i915_gem_object *i915_gem_alloc_object(struct drm_device *dev,
 	INIT_LIST_HEAD(&obj->mm_list);
 	INIT_LIST_HEAD(&obj->gtt_list);
 	INIT_LIST_HEAD(&obj->ring_list);
+	INIT_LIST_HEAD(&obj->exec_list);
 	INIT_LIST_HEAD(&obj->gpu_write_list);
 	obj->madv = I915_MADV_WILLNEED;
 	/* Avoid an unnecessary call to unbind on the first bind. */

drivers/gpu/drm/i915/i915_gem_evict.c

@@ -34,7 +34,7 @@
 static bool
 mark_free(struct drm_i915_gem_object *obj, struct list_head *unwind)
 {
-	list_add(&obj->evict_list, unwind);
+	list_add(&obj->exec_list, unwind);
 	drm_gem_object_reference(&obj->base);
 	return drm_mm_scan_add_block(obj->gtt_space);
 }
@@ -127,7 +127,7 @@ i915_gem_evict_something(struct drm_device *dev, int min_size,
 	}
 
 	/* Nothing found, clean up and bail out! */
-	list_for_each_entry(obj, &unwind_list, evict_list) {
+	list_for_each_entry(obj, &unwind_list, exec_list) {
 		ret = drm_mm_scan_remove_block(obj->gtt_space);
 		BUG_ON(ret);
 		drm_gem_object_unreference(&obj->base);
@@ -146,12 +146,12 @@ i915_gem_evict_something(struct drm_device *dev, int min_size,
 	while (!list_empty(&unwind_list)) {
 		obj = list_first_entry(&unwind_list,
 				       struct drm_i915_gem_object,
-				       evict_list);
+				       exec_list);
 		if (drm_mm_scan_remove_block(obj->gtt_space)) {
-			list_move(&obj->evict_list, &eviction_list);
+			list_move(&obj->exec_list, &eviction_list);
 			continue;
 		}
-		list_del(&obj->evict_list);
+		list_del_init(&obj->exec_list);
 		drm_gem_object_unreference(&obj->base);
 	}
 
@@ -159,10 +159,10 @@ i915_gem_evict_something(struct drm_device *dev, int min_size,
 	while (!list_empty(&eviction_list)) {
 		obj = list_first_entry(&eviction_list,
 				       struct drm_i915_gem_object,
-				       evict_list);
+				       exec_list);
 		if (ret == 0)
 			ret = i915_gem_object_unbind(obj);
-		list_del(&obj->evict_list);
+		list_del_init(&obj->exec_list);
 		drm_gem_object_unreference(&obj->base);
 	}