// 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;
}
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