Merging upstream version 6.9.7.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 388 insertions, 0 deletions

diff --git a/drivers/md/dm-vdo/action-manager.c b/drivers/md/dm-vdo/action-manager.c
new file mode 100644
index 0000000000..a0e5e7077d
--- /dev/null
+++ b/drivers/md/dm-vdo/action-manager.c
@@ -0,0 +1,388 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2023 Red Hat
+ */
+
+#include "action-manager.h"
+
+#include "memory-alloc.h"
+#include "permassert.h"
+
+#include "admin-state.h"
+#include "completion.h"
+#include "status-codes.h"
+#include "types.h"
+#include "vdo.h"
+
+/**
+ * struct action - An action to be performed in each of a set of zones.
+ * @in_use: Whether this structure is in use.
+ * @operation: The admin operation associated with this action.
+ * @preamble: The method to run on the initiator thread before the action is applied to each zone.
+ * @zone_action: The action to be performed in each zone.
+ * @conclusion: The method to run on the initiator thread after the action is applied to each zone.
+ * @parent: The object to notify when the action is complete.
+ * @context: The action specific context.
+ * @next: The action to perform after this one.
+ */
+struct action {
+	bool in_use;
+	const struct admin_state_code *operation;
+	vdo_action_preamble_fn preamble;
+	vdo_zone_action_fn zone_action;
+	vdo_action_conclusion_fn conclusion;
+	struct vdo_completion *parent;
+	void *context;
+	struct action *next;
+};
+
+/**
+ * struct action_manager - Definition of an action manager.
+ * @completion: The completion for performing actions.
+ * @state: The state of this action manager.
+ * @actions: The two action slots.
+ * @current_action: The current action slot.
+ * @zones: The number of zones in which an action is to be applied.
+ * @Scheduler: A function to schedule a default next action.
+ * @get_zone_thread_id: A function to get the id of the thread on which to apply an action to a
+ *                      zone.
+ * @initiator_thread_id: The ID of the thread on which actions may be initiated.
+ * @context: Opaque data associated with this action manager.
+ * @acting_zone: The zone currently being acted upon.
+ */
+struct action_manager {
+	struct vdo_completion completion;
+	struct admin_state state;
+	struct action actions[2];
+	struct action *current_action;
+	zone_count_t zones;
+	vdo_action_scheduler_fn scheduler;
+	vdo_zone_thread_getter_fn get_zone_thread_id;
+	thread_id_t initiator_thread_id;
+	void *context;
+	zone_count_t acting_zone;
+};
+
+static inline struct action_manager *as_action_manager(struct vdo_completion *completion)
+{
+	vdo_assert_completion_type(completion, VDO_ACTION_COMPLETION);
+	return container_of(completion, struct action_manager, completion);
+}
+
+/* Implements vdo_action_scheduler_fn. */
+static bool no_default_action(void *context __always_unused)
+{
+	return false;
+}
+
+/* Implements vdo_action_preamble_fn. */
+static void no_preamble(void *context __always_unused, struct vdo_completion *completion)
+{
+	vdo_finish_completion(completion);
+}
+
+/* Implements vdo_action_conclusion_fn. */
+static int no_conclusion(void *context __always_unused)
+{
+	return VDO_SUCCESS;
+}
+
+/**
+ * vdo_make_action_manager() - Make an action manager.
+ * @zones: The number of zones to which actions will be applied.
+ * @get_zone_thread_id: A function to get the thread id associated with a zone.
+ * @initiator_thread_id: The thread on which actions may initiated.
+ * @context: The object which holds the per-zone context for the action.
+ * @scheduler: A function to schedule a next action after an action concludes if there is no
+ *             pending action (may be NULL).
+ * @vdo: The vdo used to initialize completions.
+ * @manager_ptr: A pointer to hold the new action manager.
+ *
+ * Return: VDO_SUCCESS or an error code.
+ */
+int 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)
+{
+	struct action_manager *manager;
+	int result = vdo_allocate(1, struct action_manager, __func__, &manager);
+
+	if (result != VDO_SUCCESS)
+		return result;
+
+	*manager = (struct action_manager) {
+		.zones = zones,
+		.scheduler =
+			((scheduler == NULL) ? no_default_action : scheduler),
+		.get_zone_thread_id = get_zone_thread_id,
+		.initiator_thread_id = initiator_thread_id,
+		.context = context,
+	};
+
+	manager->actions[0].next = &manager->actions[1];
+	manager->current_action = manager->actions[1].next =
+		&manager->actions[0];
+	vdo_set_admin_state_code(&manager->state, VDO_ADMIN_STATE_NORMAL_OPERATION);
+	vdo_initialize_completion(&manager->completion, vdo, VDO_ACTION_COMPLETION);
+	*manager_ptr = manager;
+	return VDO_SUCCESS;
+}
+
+const struct admin_state_code *vdo_get_current_manager_operation(struct action_manager *manager)
+{
+	return vdo_get_admin_state_code(&manager->state);
+}
+
+void *vdo_get_current_action_context(struct action_manager *manager)
+{
+	return manager->current_action->in_use ? manager->current_action->context : NULL;
+}
+
+static void finish_action_callback(struct vdo_completion *completion);
+static void apply_to_zone(struct vdo_completion *completion);
+
+static thread_id_t get_acting_zone_thread_id(struct action_manager *manager)
+{
+	return manager->get_zone_thread_id(manager->context, manager->acting_zone);
+}
+
+static void preserve_error(struct vdo_completion *completion)
+{
+	if (completion->parent != NULL)
+		vdo_set_completion_result(completion->parent, completion->result);
+
+	vdo_reset_completion(completion);
+	vdo_run_completion(completion);
+}
+
+static void prepare_for_next_zone(struct action_manager *manager)
+{
+	vdo_prepare_completion_for_requeue(&manager->completion, apply_to_zone,
+					   preserve_error,
+					   get_acting_zone_thread_id(manager),
+					   manager->current_action->parent);
+}
+
+static void prepare_for_conclusion(struct action_manager *manager)
+{
+	vdo_prepare_completion_for_requeue(&manager->completion, finish_action_callback,
+					   preserve_error, manager->initiator_thread_id,
+					   manager->current_action->parent);
+}
+
+static void apply_to_zone(struct vdo_completion *completion)
+{
+	zone_count_t zone;
+	struct action_manager *manager = as_action_manager(completion);
+
+	VDO_ASSERT_LOG_ONLY((vdo_get_callback_thread_id() == get_acting_zone_thread_id(manager)),
+			    "%s() called on acting zones's thread", __func__);
+
+	zone = manager->acting_zone++;
+	if (manager->acting_zone == manager->zones) {
+		/*
+		 * We are about to apply to the last zone. Once that is finished, we're done, so go
+		 * back to the initiator thread and finish up.
+		 */
+		prepare_for_conclusion(manager);
+	} else {
+		/* Prepare to come back on the next zone */
+		prepare_for_next_zone(manager);
+	}
+
+	manager->current_action->zone_action(manager->context, zone, completion);
+}
+
+static void handle_preamble_error(struct vdo_completion *completion)
+{
+	/* Skip the zone actions since the preamble failed. */
+	completion->callback = finish_action_callback;
+	preserve_error(completion);
+}
+
+static void launch_current_action(struct action_manager *manager)
+{
+	struct action *action = manager->current_action;
+	int result = vdo_start_operation(&manager->state, action->operation);
+
+	if (result != VDO_SUCCESS) {
+		if (action->parent != NULL)
+			vdo_set_completion_result(action->parent, result);
+
+		/* We aren't going to run the preamble, so don't run the conclusion */
+		action->conclusion = no_conclusion;
+		finish_action_callback(&manager->completion);
+		return;
+	}
+
+	if (action->zone_action == NULL) {
+		prepare_for_conclusion(manager);
+	} else {
+		manager->acting_zone = 0;
+		vdo_prepare_completion_for_requeue(&manager->completion, apply_to_zone,
+						   handle_preamble_error,
+						   get_acting_zone_thread_id(manager),
+						   manager->current_action->parent);
+	}
+
+	action->preamble(manager->context, &manager->completion);
+}
+
+/**
+ * vdo_schedule_default_action() - Attempt to schedule the default action.
+ * @manager: The action manager.
+ *
+ * If the manager is not operating normally, the action will not be scheduled.
+ *
+ * Return: true if an action was scheduled.
+ */
+bool vdo_schedule_default_action(struct action_manager *manager)
+{
+	/* Don't schedule a default action if we are operating or not in normal operation. */
+	const struct admin_state_code *code = vdo_get_current_manager_operation(manager);
+
+	return ((code == VDO_ADMIN_STATE_NORMAL_OPERATION) &&
+		manager->scheduler(manager->context));
+}
+
+static void finish_action_callback(struct vdo_completion *completion)
+{
+	bool has_next_action;
+	int result;
+	struct action_manager *manager = as_action_manager(completion);
+	struct action action = *(manager->current_action);
+
+	manager->current_action->in_use = false;
+	manager->current_action = manager->current_action->next;
+
+	/*
+	 * We need to check this now to avoid use-after-free issues if running the conclusion or
+	 * notifying the parent results in the manager being freed.
+	 */
+	has_next_action =
+		(manager->current_action->in_use || vdo_schedule_default_action(manager));
+	result = action.conclusion(manager->context);
+	vdo_finish_operation(&manager->state, VDO_SUCCESS);
+	if (action.parent != NULL)
+		vdo_continue_completion(action.parent, result);
+
+	if (has_next_action)
+		launch_current_action(manager);
+}
+
+/**
+ * vdo_schedule_action() - Schedule an action to be applied to all zones.
+ * @manager: The action manager to schedule the action on.
+ * @preamble: A method to be invoked on the initiator thread once this action is started but before
+ *            applying to each zone; may be NULL.
+ * @action: The action to apply to each zone; may be NULL.
+ * @conclusion: A method to be invoked back on the initiator thread once the action has been
+ *              applied to all zones; may be NULL.
+ * @parent: The object to notify once the action is complete or if the action can not be scheduled;
+ *          may be NULL.
+ *
+ * The action will be launched immediately if there is no current action, or as soon as the current
+ * action completes. If there is already a pending action, this action will not be scheduled, and,
+ * if it has a parent, that parent will be notified. At least one of the preamble, action, or
+ * conclusion must not be NULL.
+ *
+ * Return: true if the action was scheduled.
+ */
+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)
+{
+	return vdo_schedule_operation(manager, VDO_ADMIN_STATE_OPERATING, preamble,
+				      action, conclusion, parent);
+}
+
+/**
+ * vdo_schedule_operation() - Schedule an operation to be applied to all zones.
+ * @manager: The action manager to schedule the action on.
+ * @operation: The operation this action will perform
+ * @preamble: A method to be invoked on the initiator thread once this action is started but before
+ *            applying to each zone; may be NULL.
+ * @action: The action to apply to each zone; may be NULL.
+ * @conclusion: A method to be invoked back on the initiator thread once the action has been
+ *              applied to all zones; may be NULL.
+ * @parent: The object to notify once the action is complete or if the action can not be scheduled;
+ *          may be NULL.
+ *
+ * The operation's action will be launched immediately if there is no current action, or as soon as
+ * the current action completes. If there is already a pending action, this operation will not be
+ * scheduled, and, if it has a parent, that parent will be notified. At least one of the preamble,
+ * action, or conclusion must not be NULL.
+ *
+ * Return: true if the action was scheduled.
+ */
+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)
+{
+	return vdo_schedule_operation_with_context(manager, operation, preamble, action,
+						   conclusion, NULL, parent);
+}
+
+/**
+ * vdo_schedule_operation_with_context() - Schedule an operation on all zones.
+ * @manager: The action manager to schedule the action on.
+ * @operation: The operation this action will perform.
+ * @preamble: A method to be invoked on the initiator thread once this action is started but before
+ *            applying to each zone; may be NULL.
+ * @action: The action to apply to each zone; may be NULL.
+ * @conclusion: A method to be invoked back on the initiator thread once the action has been
+ *              applied to all zones; may be NULL.
+ * @context: An action-specific context which may be retrieved via
+ *           vdo_get_current_action_context(); may be NULL.
+ * @parent: The object to notify once the action is complete or if the action can not be scheduled;
+ *          may be NULL.
+ *
+ * The operation's action will be launched immediately if there is no current action, or as soon as
+ * the current action completes. If there is already a pending action, this operation will not be
+ * scheduled, and, if it has a parent, that parent will be notified. At least one of the preamble,
+ * action, or conclusion must not be NULL.
+ *
+ * Return: true if the action was scheduled
+ */
+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)
+{
+	struct action *current_action;
+
+	VDO_ASSERT_LOG_ONLY((vdo_get_callback_thread_id() == manager->initiator_thread_id),
+			    "action initiated from correct thread");
+	if (!manager->current_action->in_use) {
+		current_action = manager->current_action;
+	} else if (!manager->current_action->next->in_use) {
+		current_action = manager->current_action->next;
+	} else {
+		if (parent != NULL)
+			vdo_continue_completion(parent, VDO_COMPONENT_BUSY);
+
+		return false;
+	}
+
+	*current_action = (struct action) {
+		.in_use = true,
+		.operation = operation,
+		.preamble = (preamble == NULL) ? no_preamble : preamble,
+		.zone_action = action,
+		.conclusion = (conclusion == NULL) ? no_conclusion : conclusion,
+		.context = context,
+		.parent = parent,
+		.next = current_action->next,
+	};
+
+	if (current_action == manager->current_action)
+		launch_current_action(manager);
+
+	return true;
+}