drm/i915/gt: Free request pool from virtual engines

While extremely unlikely to be populated, we could capture a request on
the virtual engine which we should free along with the virtual engine.

Fixes: 43acd6516c ("drm/i915: Keep a per-engine request pool")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200403203303.10903-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/gt/intel_engine.h

@@ -199,6 +199,8 @@ void intel_engine_cleanup(struct intel_engine_cs *engine);
 int intel_engines_init_mmio(struct intel_gt *gt);
 int intel_engines_init(struct intel_gt *gt);
 
+void intel_engine_free_request_pool(struct intel_engine_cs *engine);
+
 void intel_engines_release(struct intel_gt *gt);
 void intel_engines_free(struct intel_gt *gt);
 

drivers/gpu/drm/i915/gt/intel_engine_cs.c

@@ -426,6 +426,14 @@ void intel_engines_release(struct intel_gt *gt)
 	}
 }
 
+void intel_engine_free_request_pool(struct intel_engine_cs *engine)
+{
+	if (!engine->request_pool)
+		return;
+
+	kmem_cache_free(i915_request_slab_cache(), engine->request_pool);
+}
+
 void intel_engines_free(struct intel_gt *gt)
 {
 	struct intel_engine_cs *engine;
@@ -435,10 +443,7 @@ void intel_engines_free(struct intel_gt *gt)
 	rcu_barrier();
 
 	for_each_engine(engine, gt, id) {
-		if (engine->request_pool)
-			kmem_cache_free(i915_request_slab_cache(),
-					engine->request_pool);
-
+		intel_engine_free_request_pool(engine);
 		kfree(engine);
 		gt->engine[id] = NULL;
 	}

drivers/gpu/drm/i915/gt/intel_lrc.c

@@ -4931,6 +4931,8 @@ static void virtual_context_destroy(struct kref *kref)
 		__execlists_context_fini(&ve->context);
 	intel_context_fini(&ve->context);
 
+	intel_engine_free_request_pool(&ve->base);
+
 	kfree(ve->bonds);
 	kfree(ve);
 }