[CI v4 15/21] drm/exec: Add a snapshot capability.

["Thomas Hellström" <thomas.hellstrom@linux.intel.com>]

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
---
 drivers/gpu/drm/drm_exec.c | 39 +++++++++++++++++++++++++++++++++++++-
 include/drm/drm_exec.h     | 11 ++++++++++-
 2 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_exec.c b/drivers/gpu/drm/drm_exec.c
index 1a62ee24c1b8..334d2f9109a6 100644
--- a/drivers/gpu/drm/drm_exec.c
+++ b/drivers/gpu/drm/drm_exec.c
@@ -57,6 +57,7 @@ static void drm_exec_unlock_all(struct drm_exec *exec)
 	struct drm_gem_object *obj;
 	unsigned long index;
 
+	WARN_ON(exec->snap);
 	drm_exec_for_each_locked_object_reverse(exec, index, obj) {
 		dma_resv_unlock(obj->resv);
 		drm_gem_object_put(obj);
@@ -90,6 +91,7 @@ void drm_exec_init(struct drm_exec *exec, u32 flags, unsigned nr)
 	exec->num_objects = 0;
 	exec->contended = DRM_EXEC_DUMMY;
 	exec->prelocked = NULL;
+	exec->snap = NULL;
 }
 EXPORT_SYMBOL(drm_exec_init);
 
@@ -289,7 +291,6 @@ int drm_exec_lock_obj(struct drm_exec *exec, struct drm_gem_object *obj)
 		goto error_unlock;
 
 	return 0;
-
 error_unlock:
 	dma_resv_unlock(obj->resv);
 	return ret;
@@ -383,5 +384,41 @@ int drm_exec_prepare_array(struct drm_exec *exec,
 }
 EXPORT_SYMBOL(drm_exec_prepare_array);
 
+void drm_exec_restore(struct drm_exec *exec, struct drm_exec_snapshot *snap)
+{
+	struct drm_gem_object *obj;
+	unsigned int index;
+
+	exec->snap = snap->saved_snap;
+
+	drm_exec_for_each_locked_object_reverse(exec, index, obj) {
+		if (index + 1 == snap->num_locked)
+			break;
+
+		dma_resv_unlock(obj->resv);
+		drm_gem_object_put(obj);
+		exec->objects[index] = NULL;
+	}
+
+	exec->num_objects = snap->num_locked;
+
+	if (!exec->prelocked)
+		exec->prelocked = snap->prelocked;
+	else
+		drm_gem_object_put(snap->prelocked);
+}
+EXPORT_SYMBOL(drm_exec_restore);
+
+void drm_exec_snapshot(struct drm_exec *exec, struct drm_exec_snapshot *snap)
+{
+	snap->num_locked = exec->num_objects;
+	snap->prelocked = exec->prelocked;
+	if (snap->prelocked)
+		drm_gem_object_get(snap->prelocked);
+	snap->saved_snap = exec->snap;
+	exec->snap = snap;
+}
+EXPORT_SYMBOL(drm_exec_snapshot);
+
 MODULE_DESCRIPTION("DRM execution context");
 MODULE_LICENSE("Dual MIT/GPL");
diff --git a/include/drm/drm_exec.h b/include/drm/drm_exec.h
index a37c851a178b..0ef326f2f5f0 100644
--- a/include/drm/drm_exec.h
+++ b/include/drm/drm_exec.h
@@ -19,7 +19,6 @@ struct drm_exec {
 	 * @flags: Flags to control locking behavior
 	 */
 	u32                     flags;
-
 	/**
 	 * @ticket: WW ticket used for acquiring locks
 	 */
@@ -49,6 +48,13 @@ struct drm_exec {
 	 * @prelocked: already locked GEM object due to contention
 	 */
 	struct drm_gem_object *prelocked;
+	struct drm_exec_snapshot *snap;
+};
+
+struct drm_exec_snapshot {
+	struct drm_exec_snapshot *saved_snap;
+	struct drm_gem_object *prelocked;
+	unsigned long num_locked;
 };
 
 int drm_exec_handle_contended(struct drm_exec *exec);
@@ -156,5 +162,8 @@ int drm_exec_prepare_array(struct drm_exec *exec,
 			   struct drm_gem_object **objects,
 			   unsigned int num_objects,
 			   unsigned int num_fences);
+void drm_exec_snapshot(struct drm_exec *exec, struct drm_exec_snapshot *snap);
+void drm_exec_restore(struct drm_exec *exec, struct drm_exec_snapshot *snap);
+
 
 #endif
-- 
2.44.0