[PATCH 40/48] context-barrier-task

[Chris Wilson]

---
 drivers/gpu/drm/i915/i915_gem_context.c | 61 +++++++++++++++++++++++++
 1 file changed, 61 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 3ae1609a418a..ecd470d55d51 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -685,6 +685,67 @@ last_request_on_engine(struct i915_timeline *timeline,
 	return NULL;
 }
 
+struct context_barrier_task {
+	struct i915_active base;
+	void (*task)(void *data);
+	void *data;
+};
+
+static void cb_retire(struct i915_active *base)
+{
+	struct context_barrier_task *cb = container_of(base, typeof(*cb), base);
+
+	if (cb->task)
+		cb->task(cb->data);
+
+	i915_active_fini(&cb->base);
+	kfree(cb);
+}
+
+static int context_barrier_task(struct i915_gem_context *ctx,
+				unsigned long engines,
+				void (*task)(void *data),
+				void *data)
+{
+	struct drm_i915_private *i915 = ctx->i915;
+	struct context_barrier_task *cb;
+	struct intel_context *ce;
+	int err = 0;
+
+	lockdep_assert_held(&i915->drm.struct_mutex);
+	GEM_BUG_ON(!task);
+
+	cb = kmalloc(sizeof(*cb), GFP_KERNEL);
+	if (!cb)
+		return -ENOMEM;
+
+	i915_active_init(i915, &cb->base, cb_retire);
+	cb->task = task;
+	cb->data = data;
+
+	i915_active_acquire(&cb->base);
+	list_for_each_entry(ce, &ctx->active_engines, active_link) {
+		struct intel_engine_cs *engine = ce->engine;
+		struct i915_request *rq;
+
+		if (!(ce->engine->mask & engines))
+			continue;
+
+		rq = i915_request_alloc(engine, ctx);
+		if (IS_ERR(rq)) {
+			cb->task = NULL; /* caller need to unwind instead */
+			err = PTR_ERR(rq);
+			break;
+		}
+
+		i915_active_ref(&cb->base, rq->fence.context, rq);
+		i915_request_add(rq);
+	}
+	i915_active_release(&cb->base);
+
+	return err;
+}
+
 int i915_gem_switch_to_kernel_context(struct drm_i915_private *i915,
 				      unsigned long mask)
 {
-- 
2.20.1