[PATCH v4 2/3] drm/i915/gt: Refactor uabi engine class/instance list creation

[Andi Shyti <andi.shyti@xxxxxxxxxxxxxxx>]

For the upcoming changes we need a cleaner way to build the list
of uabi engines.

Suggested-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Signed-off-by: Andi Shyti <andi.shyti@xxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # v6.2+
---
 drivers/gpu/drm/i915/gt/intel_engine_user.c | 29 ++++++++++++---------
 1 file changed, 17 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_engine_user.c b/drivers/gpu/drm/i915/gt/intel_engine_user.c
index 833987015b8b..11cc06c0c785 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_user.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_user.c
@@ -203,7 +203,7 @@ static void engine_rename(struct intel_engine_cs *engine, const char *name, u16
 
 void intel_engines_driver_register(struct drm_i915_private *i915)
 {
-	u16 name_instance, other_instance = 0;
+	u16 class_instance[I915_LAST_UABI_ENGINE_CLASS + 2] = { };
 	struct legacy_ring ring = {};
 	struct list_head *it, *next;
 	struct rb_node **p, *prev;
@@ -214,6 +214,8 @@ void intel_engines_driver_register(struct drm_i915_private *i915)
 	prev = NULL;
 	p = &i915->uabi_engines.rb_node;
 	list_for_each_safe(it, next, &engines) {
+		u16 uabi_class;
+
 		struct intel_engine_cs *engine =
 			container_of(it, typeof(*engine), uabi_list);
 
@@ -222,15 +224,14 @@ void intel_engines_driver_register(struct drm_i915_private *i915)
 
 		GEM_BUG_ON(engine->class >= ARRAY_SIZE(uabi_classes));
 		engine->uabi_class = uabi_classes[engine->class];
-		if (engine->uabi_class == I915_NO_UABI_CLASS) {
-			name_instance = other_instance++;
-		} else {
-			GEM_BUG_ON(engine->uabi_class >=
-				   ARRAY_SIZE(i915->engine_uabi_class_count));
-			name_instance =
-				i915->engine_uabi_class_count[engine->uabi_class]++;
-		}
-		engine->uabi_instance = name_instance;
+
+		if (engine->uabi_class == I915_NO_UABI_CLASS)
+			uabi_class = I915_LAST_UABI_ENGINE_CLASS + 1;
+		else
+			uabi_class = engine->uabi_class;
+
+		GEM_BUG_ON(uabi_class >= ARRAY_SIZE(class_instance));
+		engine->uabi_instance = class_instance[uabi_class]++;
 
 		/*
 		 * Replace the internal name with the final user and log facing
@@ -238,11 +239,15 @@ void intel_engines_driver_register(struct drm_i915_private *i915)
 		 */
 		engine_rename(engine,
 			      intel_engine_class_repr(engine->class),
-			      name_instance);
+			      engine->uabi_instance);
 
-		if (engine->uabi_class == I915_NO_UABI_CLASS)
+		if (uabi_class > I915_LAST_UABI_ENGINE_CLASS)
 			continue;
 
+		GEM_BUG_ON(uabi_class >=
+			   ARRAY_SIZE(i915->engine_uabi_class_count));
+		i915->engine_uabi_class_count[uabi_class]++;
+
 		rb_link_node(&engine->uabi_node, prev, p);
 		rb_insert_color(&engine->uabi_node, &i915->uabi_engines);
 
-- 
2.43.0