| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* |
| * kernel/stop_machine.c |
| * |
| * Copyright (C) 2008, 2005 IBM Corporation. |
| * Copyright (C) 2008, 2005 Rusty Russell rusty@rustcorp.com.au |
| * Copyright (C) 2010 SUSE Linux Products GmbH |
| * Copyright (C) 2010 Tejun Heo <tj@kernel.org> |
| */ |
| #include <linux/compiler.h> |
| #include <linux/completion.h> |
| #include <linux/cpu.h> |
| #include <linux/init.h> |
| #include <linux/kthread.h> |
| #include <linux/export.h> |
| #include <linux/percpu.h> |
| #include <linux/sched.h> |
| #include <linux/stop_machine.h> |
| #include <linux/interrupt.h> |
| #include <linux/kallsyms.h> |
| #include <linux/smpboot.h> |
| #include <linux/atomic.h> |
| #include <linux/nmi.h> |
| #include <linux/sched/wake_q.h> |
| |
| /* |
| * Structure to determine completion condition and record errors. May |
| * be shared by works on different cpus. |
| */ |
| struct cpu_stop_done { |
| atomic_t nr_todo; /* nr left to execute */ |
| int ret; /* collected return value */ |
| struct completion completion; /* fired if nr_todo reaches 0 */ |
| }; |
| |
| /* the actual stopper, one per every possible cpu, enabled on online cpus */ |
| struct cpu_stopper { |
| struct task_struct *thread; |
| |
| raw_spinlock_t lock; |
| bool enabled; /* is this stopper enabled? */ |
| struct list_head works; /* list of pending works */ |
| |
| struct cpu_stop_work stop_work; /* for stop_cpus */ |
| unsigned long caller; |
| cpu_stop_fn_t fn; |
| }; |
| |
| static DEFINE_PER_CPU(struct cpu_stopper, cpu_stopper); |
| static bool stop_machine_initialized = false; |
| |
| void print_stop_info(const char *log_lvl, struct task_struct *task) |
| { |
| /* |
| * If @task is a stopper task, it cannot migrate and task_cpu() is |
| * stable. |
| */ |
| struct cpu_stopper *stopper = per_cpu_ptr(&cpu_stopper, task_cpu(task)); |
| |
| if (task != stopper->thread) |
| return; |
| |
| printk("%sStopper: %pS <- %pS\n", log_lvl, stopper->fn, (void *)stopper->caller); |
| } |
| |
| /* static data for stop_cpus */ |
| static DEFINE_MUTEX(stop_cpus_mutex); |
| static bool stop_cpus_in_progress; |
| |
| static void cpu_stop_init_done(struct cpu_stop_done *done, unsigned int nr_todo) |
| { |
| memset(done, 0, sizeof(*done)); |
| atomic_set(&done->nr_todo, nr_todo); |
| init_completion(&done->completion); |
| } |
| |
| /* signal completion unless @done is NULL */ |
| static void cpu_stop_signal_done(struct cpu_stop_done *done) |
| { |
| if (atomic_dec_and_test(&done->nr_todo)) |
| complete(&done->completion); |
| } |
| |
| static void __cpu_stop_queue_work(struct cpu_stopper *stopper, |
| struct cpu_stop_work *work, |
| struct wake_q_head *wakeq) |
| { |
| list_add_tail(&work->list, &stopper->works); |
| wake_q_add(wakeq, stopper->thread); |
| } |
| |
| /* queue @work to @stopper. if offline, @work is completed immediately */ |
| static bool cpu_stop_queue_work(unsigned int cpu, struct cpu_stop_work *work) |
| { |
| struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu); |
| DEFINE_WAKE_Q(wakeq); |
| unsigned long flags; |
| bool enabled; |
| |
| preempt_disable(); |
| raw_spin_lock_irqsave(&stopper->lock, flags); |
| enabled = stopper->enabled; |
| if (enabled) |
| __cpu_stop_queue_work(stopper, work, &wakeq); |
| else if (work->done) |
| cpu_stop_signal_done(work->done); |
| raw_spin_unlock_irqrestore(&stopper->lock, flags); |
| |
| wake_up_q(&wakeq); |
| preempt_enable(); |
| |
| return enabled; |
| } |
| |
| /** |
| * stop_one_cpu - stop a cpu |
| * @cpu: cpu to stop |
| * @fn: function to execute |
| * @arg: argument to @fn |
| * |
| * Execute @fn(@arg) on @cpu. @fn is run in a process context with |
| * the highest priority preempting any task on the cpu and |
| * monopolizing it. This function returns after the execution is |
| * complete. |
| * |
| * This function doesn't guarantee @cpu stays online till @fn |
| * completes. If @cpu goes down in the middle, execution may happen |
| * partially or fully on different cpus. @fn should either be ready |
| * for that or the caller should ensure that @cpu stays online until |
| * this function completes. |
| * |
| * CONTEXT: |
| * Might sleep. |
| * |
| * RETURNS: |
| * -ENOENT if @fn(@arg) was not executed because @cpu was offline; |
| * otherwise, the return value of @fn. |
| */ |
| int stop_one_cpu(unsigned int cpu, cpu_stop_fn_t fn, void *arg) |
| { |
| struct cpu_stop_done done; |
| struct cpu_stop_work work = { .fn = fn, .arg = arg, .done = &done, .caller = _RET_IP_ }; |
| |
| cpu_stop_init_done(&done, 1); |
| if (!cpu_stop_queue_work(cpu, &work)) |
| return -ENOENT; |
| /* |
| * In case @cpu == smp_proccessor_id() we can avoid a sleep+wakeup |
| * cycle by doing a preemption: |
| */ |
| cond_resched(); |
| wait_for_completion(&done.completion); |
| return done.ret; |
| } |
| |
| /* This controls the threads on each CPU. */ |
| enum multi_stop_state { |
| /* Dummy starting state for thread. */ |
| MULTI_STOP_NONE, |
| /* Awaiting everyone to be scheduled. */ |
| MULTI_STOP_PREPARE, |
| /* Disable interrupts. */ |
| MULTI_STOP_DISABLE_IRQ, |
| /* Run the function */ |
| MULTI_STOP_RUN, |
| /* Exit */ |
| MULTI_STOP_EXIT, |
| }; |
| |
| struct multi_stop_data { |
| cpu_stop_fn_t fn; |
| void *data; |
| /* Like num_online_cpus(), but hotplug cpu uses us, so we need this. */ |
| unsigned int num_threads; |
| const struct cpumask *active_cpus; |
| |
| enum multi_stop_state state; |
| atomic_t thread_ack; |
| }; |
| |
| static void set_state(struct multi_stop_data *msdata, |
| enum multi_stop_state newstate) |
| { |
| /* Reset ack counter. */ |
| atomic_set(&msdata->thread_ack, msdata->num_threads); |
| smp_wmb(); |
| WRITE_ONCE(msdata->state, newstate); |
| } |
| |
| /* Last one to ack a state moves to the next state. */ |
| static void ack_state(struct multi_stop_data *msdata) |
| { |
| if (atomic_dec_and_test(&msdata->thread_ack)) |
| set_state(msdata, msdata->state + 1); |
| } |
| |
| notrace void __weak stop_machine_yield(const struct cpumask *cpumask) |
| { |
| cpu_relax(); |
| } |
| |
| /* This is the cpu_stop function which stops the CPU. */ |
| static int multi_cpu_stop(void *data) |
| { |
| struct multi_stop_data *msdata = data; |
| enum multi_stop_state newstate, curstate = MULTI_STOP_NONE; |
| int cpu = smp_processor_id(), err = 0; |
| const struct cpumask *cpumask; |
| unsigned long flags; |
| bool is_active; |
| |
| /* |
| * When called from stop_machine_from_inactive_cpu(), irq might |
| * already be disabled. Save the state and restore it on exit. |
| */ |
| local_save_flags(flags); |
| |
| if (!msdata->active_cpus) { |
| cpumask = cpu_online_mask; |
| is_active = cpu == cpumask_first(cpumask); |
| } else { |
| cpumask = msdata->active_cpus; |
| is_active = cpumask_test_cpu(cpu, cpumask); |
| } |
| |
| /* Simple state machine */ |
| do { |
| /* Chill out and ensure we re-read multi_stop_state. */ |
| stop_machine_yield(cpumask); |
| newstate = READ_ONCE(msdata->state); |
| if (newstate != curstate) { |
| curstate = newstate; |
| switch (curstate) { |
| case MULTI_STOP_DISABLE_IRQ: |
| local_irq_disable(); |
| hard_irq_disable(); |
| break; |
| case MULTI_STOP_RUN: |
| if (is_active) |
| err = msdata->fn(msdata->data); |
| break; |
| default: |
| break; |
| } |
| ack_state(msdata); |
| } else if (curstate > MULTI_STOP_PREPARE) { |
| /* |
| * At this stage all other CPUs we depend on must spin |
| * in the same loop. Any reason for hard-lockup should |
| * be detected and reported on their side. |
| */ |
| touch_nmi_watchdog(); |
| } |
| rcu_momentary_dyntick_idle(); |
| } while (curstate != MULTI_STOP_EXIT); |
| |
| local_irq_restore(flags); |
| return err; |
| } |
| |
| static int cpu_stop_queue_two_works(int cpu1, struct cpu_stop_work *work1, |
| int cpu2, struct cpu_stop_work *work2) |
| { |
| struct cpu_stopper *stopper1 = per_cpu_ptr(&cpu_stopper, cpu1); |
| struct cpu_stopper *stopper2 = per_cpu_ptr(&cpu_stopper, cpu2); |
| DEFINE_WAKE_Q(wakeq); |
| int err; |
| |
| retry: |
| /* |
| * The waking up of stopper threads has to happen in the same |
| * scheduling context as the queueing. Otherwise, there is a |
| * possibility of one of the above stoppers being woken up by another |
| * CPU, and preempting us. This will cause us to not wake up the other |
| * stopper forever. |
| */ |
| preempt_disable(); |
| raw_spin_lock_irq(&stopper1->lock); |
| raw_spin_lock_nested(&stopper2->lock, SINGLE_DEPTH_NESTING); |
| |
| if (!stopper1->enabled || !stopper2->enabled) { |
| err = -ENOENT; |
| goto unlock; |
| } |
| |
| /* |
| * Ensure that if we race with __stop_cpus() the stoppers won't get |
| * queued up in reverse order leading to system deadlock. |
| * |
| * We can't miss stop_cpus_in_progress if queue_stop_cpus_work() has |
| * queued a work on cpu1 but not on cpu2, we hold both locks. |
| * |
| * It can be falsely true but it is safe to spin until it is cleared, |
| * queue_stop_cpus_work() does everything under preempt_disable(). |
| */ |
| if (unlikely(stop_cpus_in_progress)) { |
| err = -EDEADLK; |
| goto unlock; |
| } |
| |
| err = 0; |
| __cpu_stop_queue_work(stopper1, work1, &wakeq); |
| __cpu_stop_queue_work(stopper2, work2, &wakeq); |
| |
| unlock: |
| raw_spin_unlock(&stopper2->lock); |
| raw_spin_unlock_irq(&stopper1->lock); |
| |
| if (unlikely(err == -EDEADLK)) { |
| preempt_enable(); |
| |
| while (stop_cpus_in_progress) |
| cpu_relax(); |
| |
| goto retry; |
| } |
| |
| wake_up_q(&wakeq); |
| preempt_enable(); |
| |
| return err; |
| } |
| /** |
| * stop_two_cpus - stops two cpus |
| * @cpu1: the cpu to stop |
| * @cpu2: the other cpu to stop |
| * @fn: function to execute |
| * @arg: argument to @fn |
| * |
| * Stops both the current and specified CPU and runs @fn on one of them. |
| * |
| * returns when both are completed. |
| */ |
| int stop_two_cpus(unsigned int cpu1, unsigned int cpu2, cpu_stop_fn_t fn, void *arg) |
| { |
| struct cpu_stop_done done; |
| struct cpu_stop_work work1, work2; |
| struct multi_stop_data msdata; |
| |
| msdata = (struct multi_stop_data){ |
| .fn = fn, |
| .data = arg, |
| .num_threads = 2, |
| .active_cpus = cpumask_of(cpu1), |
| }; |
| |
| work1 = work2 = (struct cpu_stop_work){ |
| .fn = multi_cpu_stop, |
| .arg = &msdata, |
| .done = &done, |
| .caller = _RET_IP_, |
| }; |
| |
| cpu_stop_init_done(&done, 2); |
| set_state(&msdata, MULTI_STOP_PREPARE); |
| |
| if (cpu1 > cpu2) |
| swap(cpu1, cpu2); |
| if (cpu_stop_queue_two_works(cpu1, &work1, cpu2, &work2)) |
| return -ENOENT; |
| |
| wait_for_completion(&done.completion); |
| return done.ret; |
| } |
| |
| /** |
| * stop_one_cpu_nowait - stop a cpu but don't wait for completion |
| * @cpu: cpu to stop |
| * @fn: function to execute |
| * @arg: argument to @fn |
| * @work_buf: pointer to cpu_stop_work structure |
| * |
| * Similar to stop_one_cpu() but doesn't wait for completion. The |
| * caller is responsible for ensuring @work_buf is currently unused |
| * and will remain untouched until stopper starts executing @fn. |
| * |
| * CONTEXT: |
| * Don't care. |
| * |
| * RETURNS: |
| * true if cpu_stop_work was queued successfully and @fn will be called, |
| * false otherwise. |
| */ |
| bool stop_one_cpu_nowait(unsigned int cpu, cpu_stop_fn_t fn, void *arg, |
| struct cpu_stop_work *work_buf) |
| { |
| *work_buf = (struct cpu_stop_work){ .fn = fn, .arg = arg, .caller = _RET_IP_, }; |
| return cpu_stop_queue_work(cpu, work_buf); |
| } |
| |
| static bool queue_stop_cpus_work(const struct cpumask *cpumask, |
| cpu_stop_fn_t fn, void *arg, |
| struct cpu_stop_done *done) |
| { |
| struct cpu_stop_work *work; |
| unsigned int cpu; |
| bool queued = false; |
| |
| /* |
| * Disable preemption while queueing to avoid getting |
| * preempted by a stopper which might wait for other stoppers |
| * to enter @fn which can lead to deadlock. |
| */ |
| preempt_disable(); |
| stop_cpus_in_progress = true; |
| barrier(); |
| for_each_cpu(cpu, cpumask) { |
| work = &per_cpu(cpu_stopper.stop_work, cpu); |
| work->fn = fn; |
| work->arg = arg; |
| work->done = done; |
| work->caller = _RET_IP_; |
| if (cpu_stop_queue_work(cpu, work)) |
| queued = true; |
| } |
| barrier(); |
| stop_cpus_in_progress = false; |
| preempt_enable(); |
| |
| return queued; |
| } |
| |
| static int __stop_cpus(const struct cpumask *cpumask, |
| cpu_stop_fn_t fn, void *arg) |
| { |
| struct cpu_stop_done done; |
| |
| cpu_stop_init_done(&done, cpumask_weight(cpumask)); |
| if (!queue_stop_cpus_work(cpumask, fn, arg, &done)) |
| return -ENOENT; |
| wait_for_completion(&done.completion); |
| return done.ret; |
| } |
| |
| /** |
| * stop_cpus - stop multiple cpus |
| * @cpumask: cpus to stop |
| * @fn: function to execute |
| * @arg: argument to @fn |
| * |
| * Execute @fn(@arg) on online cpus in @cpumask. On each target cpu, |
| * @fn is run in a process context with the highest priority |
| * preempting any task on the cpu and monopolizing it. This function |
| * returns after all executions are complete. |
| * |
| * This function doesn't guarantee the cpus in @cpumask stay online |
| * till @fn completes. If some cpus go down in the middle, execution |
| * on the cpu may happen partially or fully on different cpus. @fn |
| * should either be ready for that or the caller should ensure that |
| * the cpus stay online until this function completes. |
| * |
| * All stop_cpus() calls are serialized making it safe for @fn to wait |
| * for all cpus to start executing it. |
| * |
| * CONTEXT: |
| * Might sleep. |
| * |
| * RETURNS: |
| * -ENOENT if @fn(@arg) was not executed at all because all cpus in |
| * @cpumask were offline; otherwise, 0 if all executions of @fn |
| * returned 0, any non zero return value if any returned non zero. |
| */ |
| static int stop_cpus(const struct cpumask *cpumask, cpu_stop_fn_t fn, void *arg) |
| { |
| int ret; |
| |
| /* static works are used, process one request at a time */ |
| mutex_lock(&stop_cpus_mutex); |
| ret = __stop_cpus(cpumask, fn, arg); |
| mutex_unlock(&stop_cpus_mutex); |
| return ret; |
| } |
| |
| static int cpu_stop_should_run(unsigned int cpu) |
| { |
| struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu); |
| unsigned long flags; |
| int run; |
| |
| raw_spin_lock_irqsave(&stopper->lock, flags); |
| run = !list_empty(&stopper->works); |
| raw_spin_unlock_irqrestore(&stopper->lock, flags); |
| return run; |
| } |
| |
| static void cpu_stopper_thread(unsigned int cpu) |
| { |
| struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu); |
| struct cpu_stop_work *work; |
| |
| repeat: |
| work = NULL; |
| raw_spin_lock_irq(&stopper->lock); |
| if (!list_empty(&stopper->works)) { |
| work = list_first_entry(&stopper->works, |
| struct cpu_stop_work, list); |
| list_del_init(&work->list); |
| } |
| raw_spin_unlock_irq(&stopper->lock); |
| |
| if (work) { |
| cpu_stop_fn_t fn = work->fn; |
| void *arg = work->arg; |
| struct cpu_stop_done *done = work->done; |
| int ret; |
| |
| /* cpu stop callbacks must not sleep, make in_atomic() == T */ |
| stopper->caller = work->caller; |
| stopper->fn = fn; |
| preempt_count_inc(); |
| ret = fn(arg); |
| if (done) { |
| if (ret) |
| done->ret = ret; |
| cpu_stop_signal_done(done); |
| } |
| preempt_count_dec(); |
| stopper->fn = NULL; |
| stopper->caller = 0; |
| WARN_ONCE(preempt_count(), |
| "cpu_stop: %ps(%p) leaked preempt count\n", fn, arg); |
| goto repeat; |
| } |
| } |
| |
| void stop_machine_park(int cpu) |
| { |
| struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu); |
| /* |
| * Lockless. cpu_stopper_thread() will take stopper->lock and flush |
| * the pending works before it parks, until then it is fine to queue |
| * the new works. |
| */ |
| stopper->enabled = false; |
| kthread_park(stopper->thread); |
| } |
| |
| static void cpu_stop_create(unsigned int cpu) |
| { |
| sched_set_stop_task(cpu, per_cpu(cpu_stopper.thread, cpu)); |
| } |
| |
| static void cpu_stop_park(unsigned int cpu) |
| { |
| struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu); |
| |
| WARN_ON(!list_empty(&stopper->works)); |
| } |
| |
| void stop_machine_unpark(int cpu) |
| { |
| struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu); |
| |
| stopper->enabled = true; |
| kthread_unpark(stopper->thread); |
| } |
| |
| static struct smp_hotplug_thread cpu_stop_threads = { |
| .store = &cpu_stopper.thread, |
| .thread_should_run = cpu_stop_should_run, |
| .thread_fn = cpu_stopper_thread, |
| .thread_comm = "migration/%u", |
| .create = cpu_stop_create, |
| .park = cpu_stop_park, |
| .selfparking = true, |
| }; |
| |
| static int __init cpu_stop_init(void) |
| { |
| unsigned int cpu; |
| |
| for_each_possible_cpu(cpu) { |
| struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu); |
| |
| raw_spin_lock_init(&stopper->lock); |
| INIT_LIST_HEAD(&stopper->works); |
| } |
| |
| BUG_ON(smpboot_register_percpu_thread(&cpu_stop_threads)); |
| stop_machine_unpark(raw_smp_processor_id()); |
| stop_machine_initialized = true; |
| return 0; |
| } |
| early_initcall(cpu_stop_init); |
| |
| int stop_machine_cpuslocked(cpu_stop_fn_t fn, void *data, |
| const struct cpumask *cpus) |
| { |
| struct multi_stop_data msdata = { |
| .fn = fn, |
| .data = data, |
| .num_threads = num_online_cpus(), |
| .active_cpus = cpus, |
| }; |
| |
| lockdep_assert_cpus_held(); |
| |
| if (!stop_machine_initialized) { |
| /* |
| * Handle the case where stop_machine() is called |
| * early in boot before stop_machine() has been |
| * initialized. |
| */ |
| unsigned long flags; |
| int ret; |
| |
| WARN_ON_ONCE(msdata.num_threads != 1); |
| |
| local_irq_save(flags); |
| hard_irq_disable(); |
| ret = (*fn)(data); |
| local_irq_restore(flags); |
| |
| return ret; |
| } |
| |
| /* Set the initial state and stop all online cpus. */ |
| set_state(&msdata, MULTI_STOP_PREPARE); |
| return stop_cpus(cpu_online_mask, multi_cpu_stop, &msdata); |
| } |
| |
| int stop_machine(cpu_stop_fn_t fn, void *data, const struct cpumask *cpus) |
| { |
| int ret; |
| |
| /* No CPUs can come up or down during this. */ |
| cpus_read_lock(); |
| ret = stop_machine_cpuslocked(fn, data, cpus); |
| cpus_read_unlock(); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(stop_machine); |
| |
| #ifdef CONFIG_SCHED_SMT |
| int stop_core_cpuslocked(unsigned int cpu, cpu_stop_fn_t fn, void *data) |
| { |
| const struct cpumask *smt_mask = cpu_smt_mask(cpu); |
| |
| struct multi_stop_data msdata = { |
| .fn = fn, |
| .data = data, |
| .num_threads = cpumask_weight(smt_mask), |
| .active_cpus = smt_mask, |
| }; |
| |
| lockdep_assert_cpus_held(); |
| |
| /* Set the initial state and stop all online cpus. */ |
| set_state(&msdata, MULTI_STOP_PREPARE); |
| return stop_cpus(smt_mask, multi_cpu_stop, &msdata); |
| } |
| EXPORT_SYMBOL_GPL(stop_core_cpuslocked); |
| #endif |
| |
| /** |
| * stop_machine_from_inactive_cpu - stop_machine() from inactive CPU |
| * @fn: the function to run |
| * @data: the data ptr for the @fn() |
| * @cpus: the cpus to run the @fn() on (NULL = any online cpu) |
| * |
| * This is identical to stop_machine() but can be called from a CPU which |
| * is not active. The local CPU is in the process of hotplug (so no other |
| * CPU hotplug can start) and not marked active and doesn't have enough |
| * context to sleep. |
| * |
| * This function provides stop_machine() functionality for such state by |
| * using busy-wait for synchronization and executing @fn directly for local |
| * CPU. |
| * |
| * CONTEXT: |
| * Local CPU is inactive. Temporarily stops all active CPUs. |
| * |
| * RETURNS: |
| * 0 if all executions of @fn returned 0, any non zero return value if any |
| * returned non zero. |
| */ |
| int stop_machine_from_inactive_cpu(cpu_stop_fn_t fn, void *data, |
| const struct cpumask *cpus) |
| { |
| struct multi_stop_data msdata = { .fn = fn, .data = data, |
| .active_cpus = cpus }; |
| struct cpu_stop_done done; |
| int ret; |
| |
| /* Local CPU must be inactive and CPU hotplug in progress. */ |
| BUG_ON(cpu_active(raw_smp_processor_id())); |
| msdata.num_threads = num_active_cpus() + 1; /* +1 for local */ |
| |
| /* No proper task established and can't sleep - busy wait for lock. */ |
| while (!mutex_trylock(&stop_cpus_mutex)) |
| cpu_relax(); |
| |
| /* Schedule work on other CPUs and execute directly for local CPU */ |
| set_state(&msdata, MULTI_STOP_PREPARE); |
| cpu_stop_init_done(&done, num_active_cpus()); |
| queue_stop_cpus_work(cpu_active_mask, multi_cpu_stop, &msdata, |
| &done); |
| ret = multi_cpu_stop(&msdata); |
| |
| /* Busy wait for completion. */ |
| while (!completion_done(&done.completion)) |
| cpu_relax(); |
| |
| mutex_unlock(&stop_cpus_mutex); |
| return ret ?: done.ret; |
| } |