From 83e9d5d2d45e518deb8cb843bd2e41548c6bb9b2 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Fri, 17 Jul 2015 13:43:18 +0200 Subject: [PATCH] s390/zcrypt: fix suspend/resume of AP bus devices If there are no devices on the AP bus there will not be a single call to the per-device ap_bus_suspend function. Even worse, there will not be a call to the per-device ap_bus_resume either and the AP will fail so resume correctly. Introduce a bus specific dev_pm_ops to suspend / resume the AP bus related things. While we are at it, simplify the power management code of the AP bus. Reviewd-by: Ingo Tuchscherer Signed-off-by: Martin Schwidefsky --- drivers/s390/crypto/ap_bus.c | 326 +++++++++++++++++------------------ 1 file changed, 160 insertions(+), 166 deletions(-) diff --git a/drivers/s390/crypto/ap_bus.c b/drivers/s390/crypto/ap_bus.c index 80af1bd473e1..8dfd1c9163a7 100644 --- a/drivers/s390/crypto/ap_bus.c +++ b/drivers/s390/crypto/ap_bus.c @@ -37,6 +37,7 @@ #include #include #include +#include #include #include #include @@ -52,8 +53,6 @@ static void ap_scan_bus(struct work_struct *); static void ap_poll_all(unsigned long); static enum hrtimer_restart ap_poll_timeout(struct hrtimer *); -static int ap_poll_thread_start(void); -static void ap_poll_thread_stop(void); static void ap_request_timeout(unsigned long); static inline void ap_schedule_poll_timer(void); static int __ap_poll_device(struct ap_device *ap_dev, unsigned long *flags); @@ -614,6 +613,78 @@ static void ap_decrease_queue_count(struct ap_device *ap_dev) ap_dev->reset = AP_RESET_IGNORE; } +/** + * ap_poll_thread(): Thread that polls for finished requests. + * @data: Unused pointer + * + * AP bus poll thread. The purpose of this thread is to poll for + * finished requests in a loop if there is a "free" cpu - that is + * a cpu that doesn't have anything better to do. The polling stops + * as soon as there is another task or if all messages have been + * delivered. + */ +static int ap_poll_thread(void *data) +{ + DECLARE_WAITQUEUE(wait, current); + unsigned long flags; + struct ap_device *ap_dev; + + set_user_nice(current, MAX_NICE); + set_freezable(); + while (!kthread_should_stop()) { + add_wait_queue(&ap_poll_wait, &wait); + set_current_state(TASK_INTERRUPTIBLE); + if (ap_suspend_flag || + atomic_read(&ap_poll_requests) <= 0) { + schedule(); + try_to_freeze(); + } + set_current_state(TASK_RUNNING); + remove_wait_queue(&ap_poll_wait, &wait); + + if (need_resched()) { + schedule(); + try_to_freeze(); + continue; + } + + flags = 0; + spin_lock_bh(&ap_device_list_lock); + list_for_each_entry(ap_dev, &ap_device_list, list) { + spin_lock(&ap_dev->lock); + __ap_poll_device(ap_dev, &flags); + spin_unlock(&ap_dev->lock); + } + spin_unlock_bh(&ap_device_list_lock); + } while (!kthread_should_stop()); + return 0; +} + +static int ap_poll_thread_start(void) +{ + int rc; + + if (ap_using_interrupts() || ap_poll_kthread) + return 0; + mutex_lock(&ap_poll_thread_mutex); + ap_poll_kthread = kthread_run(ap_poll_thread, NULL, "appoll"); + rc = PTR_RET(ap_poll_kthread); + if (rc) + ap_poll_kthread = NULL; + mutex_unlock(&ap_poll_thread_mutex); + return rc; +} + +static void ap_poll_thread_stop(void) +{ + if (!ap_poll_kthread) + return; + mutex_lock(&ap_poll_thread_mutex); + kthread_stop(ap_poll_kthread); + ap_poll_kthread = NULL; + mutex_unlock(&ap_poll_thread_mutex); +} + /* * AP device related attributes. */ @@ -827,25 +898,11 @@ static int ap_uevent (struct device *dev, struct kobj_uevent_env *env) return retval; } -static int ap_bus_suspend(struct device *dev, pm_message_t state) +static int ap_dev_suspend(struct device *dev, pm_message_t state) { struct ap_device *ap_dev = to_ap_dev(dev); unsigned long flags; - if (!ap_suspend_flag) { - ap_suspend_flag = 1; - - /* Disable scanning for devices, thus we do not want to scan - * for them after removing. - */ - del_timer_sync(&ap_config_timer); - if (ap_work_queue != NULL) { - destroy_workqueue(ap_work_queue); - ap_work_queue = NULL; - } - - tasklet_disable(&ap_tasklet); - } /* Poll on the device until all requests are finished. */ do { flags = 0; @@ -854,72 +911,86 @@ static int ap_bus_suspend(struct device *dev, pm_message_t state) spin_unlock_bh(&ap_dev->lock); } while ((flags & 1) || (flags & 2)); - spin_lock_bh(&ap_dev->lock); - ap_dev->unregistered = 1; - spin_unlock_bh(&ap_dev->lock); + return 0; +} +static int ap_dev_resume(struct device *dev) +{ return 0; } -static int ap_bus_resume(struct device *dev) +static void ap_bus_suspend(void) +{ + ap_suspend_flag = 1; + /* + * Disable scanning for devices, thus we do not want to scan + * for them after removing. + */ + del_timer_sync(&ap_config_timer); + flush_workqueue(ap_work_queue); + tasklet_disable(&ap_tasklet); +} + +static int __ap_devices_unregister(struct device *dev, void *dummy) +{ + device_unregister(dev); + return 0; +} + +static void ap_bus_resume(void) { - struct ap_device *ap_dev = to_ap_dev(dev); int rc; - if (ap_suspend_flag) { - ap_suspend_flag = 0; - if (ap_interrupts_available()) { - if (!ap_using_interrupts()) { - rc = register_adapter_interrupt(&ap_airq); - ap_airq_flag = (rc == 0); - } - } else { - if (ap_using_interrupts()) { - unregister_adapter_interrupt(&ap_airq); - ap_airq_flag = 0; - } - } - ap_query_configuration(); - if (!user_set_domain) { - ap_domain_index = -1; - ap_select_domain(); - } - init_timer(&ap_config_timer); - ap_config_timer.function = ap_config_timeout; - ap_config_timer.data = 0; - ap_config_timer.expires = jiffies + ap_config_time * HZ; - add_timer(&ap_config_timer); - ap_work_queue = create_singlethread_workqueue("kapwork"); - if (!ap_work_queue) - return -ENOMEM; - tasklet_enable(&ap_tasklet); - if (!ap_using_interrupts()) - ap_schedule_poll_timer(); - else - tasklet_schedule(&ap_tasklet); - if (ap_thread_flag) - rc = ap_poll_thread_start(); - else - rc = 0; - } else - rc = 0; - if (AP_QID_QUEUE(ap_dev->qid) != ap_domain_index) { - spin_lock_bh(&ap_dev->lock); - ap_dev->qid = AP_MKQID(AP_QID_DEVICE(ap_dev->qid), - ap_domain_index); - spin_unlock_bh(&ap_dev->lock); + /* Unconditionally remove all AP devices */ + bus_for_each_dev(&ap_bus_type, NULL, NULL, __ap_devices_unregister); + /* Reset thin interrupt setting */ + if (ap_interrupts_available() && !ap_using_interrupts()) { + rc = register_adapter_interrupt(&ap_airq); + ap_airq_flag = (rc == 0); } + if (!ap_interrupts_available() && ap_using_interrupts()) { + unregister_adapter_interrupt(&ap_airq); + ap_airq_flag = 0; + } + /* Reset domain */ + if (!user_set_domain) + ap_domain_index = -1; + /* Get things going again */ + ap_suspend_flag = 0; + if (ap_airq_flag) + xchg(ap_airq.lsi_ptr, 0); + tasklet_enable(&ap_tasklet); queue_work(ap_work_queue, &ap_config_work); + wake_up(&ap_poll_wait); +} - return rc; +static int ap_power_event(struct notifier_block *this, unsigned long event, + void *ptr) +{ + switch (event) { + case PM_HIBERNATION_PREPARE: + case PM_SUSPEND_PREPARE: + ap_bus_suspend(); + break; + case PM_POST_HIBERNATION: + case PM_POST_SUSPEND: + ap_bus_resume(); + break; + default: + break; + } + return NOTIFY_DONE; } +static struct notifier_block ap_power_notifier = { + .notifier_call = ap_power_event, +}; static struct bus_type ap_bus_type = { .name = "ap", .match = &ap_bus_match, .uevent = &ap_uevent, - .suspend = ap_bus_suspend, - .resume = ap_bus_resume + .suspend = ap_dev_suspend, + .resume = ap_dev_resume, }; static int ap_device_probe(struct device *dev) @@ -1017,6 +1088,8 @@ EXPORT_SYMBOL(ap_driver_unregister); void ap_bus_force_rescan(void) { + if (ap_suspend_flag) + return; /* reconfigure the AP bus rescan timer. */ mod_timer(&ap_config_timer, jiffies + ap_config_time * HZ); /* processing a asynchronous bus rescan */ @@ -1102,9 +1175,8 @@ static ssize_t ap_poll_thread_store(struct bus_type *bus, if (flag) { rc = ap_poll_thread_start(); if (rc) - return rc; - } - else + count = rc; + } else ap_poll_thread_stop(); return count; } @@ -1309,7 +1381,8 @@ out: static void ap_interrupt_handler(struct airq_struct *airq) { inc_irq_stat(IRQIO_APB); - tasklet_schedule(&ap_tasklet); + if (!ap_suspend_flag) + tasklet_schedule(&ap_tasklet); } /** @@ -1341,9 +1414,8 @@ static void ap_scan_bus(struct work_struct *unused) int rc, i; ap_query_configuration(); - if (ap_select_domain() != 0) { + if (ap_select_domain() != 0) return; - } for (i = 0; i < AP_DEVICES; i++) { qid = AP_MKQID(i, ap_domain_index); @@ -1422,9 +1494,10 @@ static void ap_scan_bus(struct work_struct *unused) } } -static void -ap_config_timeout(unsigned long ptr) +static void ap_config_timeout(unsigned long ptr) { + if (ap_suspend_flag) + return; queue_work(ap_work_queue, &ap_config_work); ap_config_timer.expires = jiffies + ap_config_time * HZ; add_timer(&ap_config_timer); @@ -1706,7 +1779,8 @@ EXPORT_SYMBOL(ap_cancel_message); */ static enum hrtimer_restart ap_poll_timeout(struct hrtimer *unused) { - tasklet_schedule(&ap_tasklet); + if (!ap_suspend_flag) + tasklet_schedule(&ap_tasklet); return HRTIMER_NORESTART; } @@ -1777,84 +1851,6 @@ static void ap_poll_all(unsigned long dummy) __ap_schedule_poll_timer(); } -/** - * ap_poll_thread(): Thread that polls for finished requests. - * @data: Unused pointer - * - * AP bus poll thread. The purpose of this thread is to poll for - * finished requests in a loop if there is a "free" cpu - that is - * a cpu that doesn't have anything better to do. The polling stops - * as soon as there is another task or if all messages have been - * delivered. - */ -static int ap_poll_thread(void *data) -{ - DECLARE_WAITQUEUE(wait, current); - unsigned long flags; - int requests; - struct ap_device *ap_dev; - - set_user_nice(current, MAX_NICE); - while (1) { - if (ap_suspend_flag) - return 0; - if (need_resched()) { - schedule(); - continue; - } - add_wait_queue(&ap_poll_wait, &wait); - set_current_state(TASK_INTERRUPTIBLE); - if (kthread_should_stop()) - break; - requests = atomic_read(&ap_poll_requests); - if (requests <= 0) - schedule(); - set_current_state(TASK_RUNNING); - remove_wait_queue(&ap_poll_wait, &wait); - - flags = 0; - spin_lock_bh(&ap_device_list_lock); - list_for_each_entry(ap_dev, &ap_device_list, list) { - spin_lock(&ap_dev->lock); - __ap_poll_device(ap_dev, &flags); - spin_unlock(&ap_dev->lock); - } - spin_unlock_bh(&ap_device_list_lock); - } - set_current_state(TASK_RUNNING); - remove_wait_queue(&ap_poll_wait, &wait); - return 0; -} - -static int ap_poll_thread_start(void) -{ - int rc; - - if (ap_using_interrupts() || ap_suspend_flag) - return 0; - mutex_lock(&ap_poll_thread_mutex); - if (!ap_poll_kthread) { - ap_poll_kthread = kthread_run(ap_poll_thread, NULL, "appoll"); - rc = PTR_RET(ap_poll_kthread); - if (rc) - ap_poll_kthread = NULL; - } - else - rc = 0; - mutex_unlock(&ap_poll_thread_mutex); - return rc; -} - -static void ap_poll_thread_stop(void) -{ - mutex_lock(&ap_poll_thread_mutex); - if (ap_poll_kthread) { - kthread_stop(ap_poll_kthread); - ap_poll_kthread = NULL; - } - mutex_unlock(&ap_poll_thread_mutex); -} - /** * ap_request_timeout(): Handling of request timeouts * @data: Holds the AP device. @@ -1865,6 +1861,8 @@ static void ap_request_timeout(unsigned long data) { struct ap_device *ap_dev = (struct ap_device *) data; + if (ap_suspend_flag) + return; if (ap_dev->reset == AP_RESET_ARMED) { ap_dev->reset = AP_RESET_DO; @@ -1990,8 +1988,14 @@ int __init ap_module_init(void) goto out_work; } + rc = register_pm_notifier(&ap_power_notifier); + if (rc) + goto out_pm; + return 0; +out_pm: + ap_poll_thread_stop(); out_work: del_timer_sync(&ap_config_timer); hrtimer_cancel(&ap_poll_timer); @@ -2010,11 +2014,6 @@ out: return rc; } -static int __ap_match_all(struct device *dev, void *data) -{ - return 1; -} - /** * ap_modules_exit(): The module termination code * @@ -2023,7 +2022,6 @@ static int __ap_match_all(struct device *dev, void *data) void ap_module_exit(void) { int i; - struct device *dev; ap_reset_domain(); ap_poll_thread_stop(); @@ -2031,14 +2029,10 @@ void ap_module_exit(void) hrtimer_cancel(&ap_poll_timer); destroy_workqueue(ap_work_queue); tasklet_kill(&ap_tasklet); - while ((dev = bus_find_device(&ap_bus_type, NULL, NULL, - __ap_match_all))) - { - device_unregister(dev); - put_device(dev); - } + bus_for_each_dev(&ap_bus_type, NULL, NULL, __ap_devices_unregister); for (i = 0; ap_bus_attrs[i]; i++) bus_remove_file(&ap_bus_type, ap_bus_attrs[i]); + unregister_pm_notifier(&ap_power_notifier); root_device_unregister(ap_root_device); bus_unregister(&ap_bus_type); kfree(ap_configuration); -- 2.20.1