1 files changed, 110 insertions, 0 deletions
diff --git a/drivers/md/dm-vdo/action-manager.h b/drivers/md/dm-vdo/action-manager.h
new file mode 100644
index 000000000..b0a8d3ddf
--- /dev/null
+++ b/drivers/md/dm-vdo/action-manager.h
@@ -0,0 +1,110 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright 2023 Red Hat
+ */
+
+#ifndef VDO_ACTION_MANAGER_H
+#define VDO_ACTION_MANAGER_H
+
+#include "admin-state.h"
+#include "types.h"
+
+/*
+ * An action_manager provides a generic mechanism for applying actions to multi-zone entities (such
+ * as the block map or slab depot). Each action manager is tied to a specific context for which it
+ * manages actions. The manager ensures that only one action is active on that context at a time,
+ * and supports at most one pending action. Calls to schedule an action when there is already a
+ * pending action will result in VDO_COMPONENT_BUSY errors. Actions may only be submitted to the
+ * action manager from a single thread (which thread is determined when the action manager is
+ * constructed).
+ *
+ * A scheduled action consists of four components:
+ *
+ *   preamble
+ *     an optional method to be run on the initiator thread before applying the action to all zones
+ *   zone_action
+ *     an optional method to be applied to each of the zones
+ *   conclusion
+ *     an optional method to be run on the initiator thread once the per-zone method has been
+ *     applied to all zones
+ *   parent
+ *     an optional completion to be finished once the conclusion is done
+ *
+ * At least one of the three methods must be provided.
+ */
+
+/*
+ * A function which is to be applied asynchronously to a set of zones.
+ * @context: The object which holds the per-zone context for the action
+ * @zone_number: The number of zone to which the action is being applied
+ * @parent: The object to notify when the action is complete
+ */
+typedef void (*vdo_zone_action_fn)(void *context, zone_count_t zone_number,
+				   struct vdo_completion *parent);
+
+/*
+ * A function which is to be applied asynchronously on an action manager's initiator thread as the
+ * preamble of an action.
+ * @context: The object which holds the per-zone context for the action
+ * @parent: The object to notify when the action is complete
+ */
+typedef void (*vdo_action_preamble_fn)(void *context, struct vdo_completion *parent);
+
+/*
+ * A function which will run on the action manager's initiator thread as the conclusion of an
+ * action.
+ * @context: The object which holds the per-zone context for the action
+ *
+ * Return: VDO_SUCCESS or an error
+ */
+typedef int (*vdo_action_conclusion_fn)(void *context);
+
+/*
+ * A function to schedule an action.
+ * @context: The object which holds the per-zone context for the action
+ *
+ * Return: true if an action was scheduled
+ */
+typedef bool (*vdo_action_scheduler_fn)(void *context);
+
+/*
+ * A function to get the id of the thread associated with a given zone.
+ * @context: The action context
+ * @zone_number: The number of the zone for which the thread ID is desired
+ */
+typedef thread_id_t (*vdo_zone_thread_getter_fn)(void *context, zone_count_t zone_number);
+
+struct action_manager;
+
+int __must_check vdo_make_action_manager(zone_count_t zones,
+					 vdo_zone_thread_getter_fn get_zone_thread_id,
+					 thread_id_t initiator_thread_id, void *context,
+					 vdo_action_scheduler_fn scheduler,
+					 struct vdo *vdo,
+					 struct action_manager **manager_ptr);
+
+const struct admin_state_code *__must_check
+vdo_get_current_manager_operation(struct action_manager *manager);
+
+void * __must_check vdo_get_current_action_context(struct action_manager *manager);
+
+bool vdo_schedule_default_action(struct action_manager *manager);
+
+bool vdo_schedule_action(struct action_manager *manager, vdo_action_preamble_fn preamble,
+			 vdo_zone_action_fn action, vdo_action_conclusion_fn conclusion,
+			 struct vdo_completion *parent);
+
+bool vdo_schedule_operation(struct action_manager *manager,
+			    const struct admin_state_code *operation,
+			    vdo_action_preamble_fn preamble, vdo_zone_action_fn action,
+			    vdo_action_conclusion_fn conclusion,
+			    struct vdo_completion *parent);
+
+bool vdo_schedule_operation_with_context(struct action_manager *manager,
+					 const struct admin_state_code *operation,
+					 vdo_action_preamble_fn preamble,
+					 vdo_zone_action_fn action,
+					 vdo_action_conclusion_fn conclusion,
+					 void *context, struct vdo_completion *parent);
+
+#endif /* VDO_ACTION_MANAGER_H */