1 files changed, 55 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/gt/intel_context.h b/drivers/gpu/drm/i915/gt/intel_context.h
index c41098950746..246c37d72cd7 100644
--- a/drivers/gpu/drm/i915/gt/intel_context.h
+++ b/drivers/gpu/drm/i915/gt/intel_context.h
@@ -44,6 +44,54 @@ void intel_context_free(struct intel_context *ce);
 int intel_context_reconfigure_sseu(struct intel_context *ce,
 				   const struct intel_sseu sseu);
 
+#define PARENT_SCRATCH_SIZE	PAGE_SIZE
+
+static inline bool intel_context_is_child(struct intel_context *ce)
+{
+	return !!ce->parallel.parent;
+}
+
+static inline bool intel_context_is_parent(struct intel_context *ce)
+{
+	return !!ce->parallel.number_children;
+}
+
+static inline bool intel_context_is_pinned(struct intel_context *ce);
+
+static inline struct intel_context *
+intel_context_to_parent(struct intel_context *ce)
+{
+	if (intel_context_is_child(ce)) {
+		/*
+		 * The parent holds ref count to the child so it is always safe
+		 * for the parent to access the child, but the child has a
+		 * pointer to the parent without a ref. To ensure this is safe
+		 * the child should only access the parent pointer while the
+		 * parent is pinned.
+		 */
+		GEM_BUG_ON(!intel_context_is_pinned(ce->parallel.parent));
+
+		return ce->parallel.parent;
+	} else {
+		return ce;
+	}
+}
+
+static inline bool intel_context_is_parallel(struct intel_context *ce)
+{
+	return intel_context_is_child(ce) || intel_context_is_parent(ce);
+}
+
+void intel_context_bind_parent_child(struct intel_context *parent,
+				     struct intel_context *child);
+
+#define for_each_child(parent, ce)\
+	list_for_each_entry(ce, &(parent)->parallel.child_list,\
+			    parallel.child_link)
+#define for_each_child_safe(parent, ce, cn)\
+	list_for_each_entry_safe(ce, cn, &(parent)->parallel.child_list,\
+				 parallel.child_link)
+
 /**
  * intel_context_lock_pinned - Stablises the 'pinned' status of the HW context
  * @ce - the context
@@ -193,7 +241,13 @@ intel_context_timeline_lock(struct intel_context *ce)
 	struct intel_timeline *tl = ce->timeline;
 	int err;
 
-	err = mutex_lock_interruptible(&tl->mutex);
+	if (intel_context_is_parent(ce))
+		err = mutex_lock_interruptible_nested(&tl->mutex, 0);
+	else if (intel_context_is_child(ce))
+		err = mutex_lock_interruptible_nested(&tl->mutex,
+						      ce->parallel.child_index + 1);
+	else
+		err = mutex_lock_interruptible(&tl->mutex);
 	if (err)
 		return ERR_PTR(err);