From 8ee294cd9def0004887da7f44b80563493b0a097 Mon Sep 17 00:00:00 2001 From: Dmitry Torokhov Date: Mon, 15 Nov 2010 01:39:57 -0800 Subject: [PATCH] Input: serio - convert to common workqueue instead of a thread Instead of creating an exclusive thread to handle serio events (which happen rarely), let's switch to using common workqueue. With the arrival of concurrency-managed workqueue infrastructure we are not concerned that our callers or callees also using workqueue (no deadlocks anymore) and it should reduce total number of threads in the system. Signed-off-by: Dmitry Torokhov --- drivers/input/serio/serio.c | 155 ++++++++++++++++-------------------- 1 file changed, 69 insertions(+), 86 deletions(-) diff --git a/drivers/input/serio/serio.c b/drivers/input/serio/serio.c index 405bf214527c..db5b0bca1a1a 100644 --- a/drivers/input/serio/serio.c +++ b/drivers/input/serio/serio.c @@ -32,10 +32,9 @@ #include #include #include -#include #include #include -#include +#include #include MODULE_AUTHOR("Vojtech Pavlik "); @@ -44,7 +43,7 @@ MODULE_LICENSE("GPL"); /* * serio_mutex protects entire serio subsystem and is taken every time - * serio port or driver registrered or unregistered. + * serio port or driver registered or unregistered. */ static DEFINE_MUTEX(serio_mutex); @@ -165,58 +164,22 @@ struct serio_event { static DEFINE_SPINLOCK(serio_event_lock); /* protects serio_event_list */ static LIST_HEAD(serio_event_list); -static DECLARE_WAIT_QUEUE_HEAD(serio_wait); -static struct task_struct *serio_task; -static int serio_queue_event(void *object, struct module *owner, - enum serio_event_type event_type) +static struct serio_event *serio_get_event(void) { + struct serio_event *event = NULL; unsigned long flags; - struct serio_event *event; - int retval = 0; spin_lock_irqsave(&serio_event_lock, flags); - /* - * Scan event list for the other events for the same serio port, - * starting with the most recent one. If event is the same we - * do not need add new one. If event is of different type we - * need to add this event and should not look further because - * we need to preseve sequence of distinct events. - */ - list_for_each_entry_reverse(event, &serio_event_list, node) { - if (event->object == object) { - if (event->type == event_type) - goto out; - break; - } - } - - event = kmalloc(sizeof(struct serio_event), GFP_ATOMIC); - if (!event) { - pr_err("Not enough memory to queue event %d\n", event_type); - retval = -ENOMEM; - goto out; - } - - if (!try_module_get(owner)) { - pr_warning("Can't get module reference, dropping event %d\n", - event_type); - kfree(event); - retval = -EINVAL; - goto out; + if (!list_empty(&serio_event_list)) { + event = list_first_entry(&serio_event_list, + struct serio_event, node); + list_del_init(&event->node); } - event->type = event_type; - event->object = object; - event->owner = owner; - - list_add_tail(&event->node, &serio_event_list); - wake_up(&serio_wait); - -out: spin_unlock_irqrestore(&serio_event_lock, flags); - return retval; + return event; } static void serio_free_event(struct serio_event *event) @@ -250,25 +213,7 @@ static void serio_remove_duplicate_events(struct serio_event *event) spin_unlock_irqrestore(&serio_event_lock, flags); } - -static struct serio_event *serio_get_event(void) -{ - struct serio_event *event = NULL; - unsigned long flags; - - spin_lock_irqsave(&serio_event_lock, flags); - - if (!list_empty(&serio_event_list)) { - event = list_first_entry(&serio_event_list, - struct serio_event, node); - list_del_init(&event->node); - } - - spin_unlock_irqrestore(&serio_event_lock, flags); - return event; -} - -static void serio_handle_event(void) +static void serio_handle_event(struct work_struct *work) { struct serio_event *event; @@ -307,6 +252,59 @@ static void serio_handle_event(void) mutex_unlock(&serio_mutex); } +static DECLARE_WORK(serio_event_work, serio_handle_event); + +static int serio_queue_event(void *object, struct module *owner, + enum serio_event_type event_type) +{ + unsigned long flags; + struct serio_event *event; + int retval = 0; + + spin_lock_irqsave(&serio_event_lock, flags); + + /* + * Scan event list for the other events for the same serio port, + * starting with the most recent one. If event is the same we + * do not need add new one. If event is of different type we + * need to add this event and should not look further because + * we need to preseve sequence of distinct events. + */ + list_for_each_entry_reverse(event, &serio_event_list, node) { + if (event->object == object) { + if (event->type == event_type) + goto out; + break; + } + } + + event = kmalloc(sizeof(struct serio_event), GFP_ATOMIC); + if (!event) { + pr_err("Not enough memory to queue event %d\n", event_type); + retval = -ENOMEM; + goto out; + } + + if (!try_module_get(owner)) { + pr_warning("Can't get module reference, dropping event %d\n", + event_type); + kfree(event); + retval = -EINVAL; + goto out; + } + + event->type = event_type; + event->object = object; + event->owner = owner; + + list_add_tail(&event->node, &serio_event_list); + schedule_work(&serio_event_work); + +out: + spin_unlock_irqrestore(&serio_event_lock, flags); + return retval; +} + /* * Remove all events that have been submitted for a given * object, be it serio port or driver. @@ -356,18 +354,6 @@ static struct serio *serio_get_pending_child(struct serio *parent) return child; } -static int serio_thread(void *nothing) -{ - do { - serio_handle_event(); - wait_event_interruptible(serio_wait, - kthread_should_stop() || !list_empty(&serio_event_list)); - } while (!kthread_should_stop()); - - return 0; -} - - /* * Serio port operations */ @@ -1040,21 +1026,18 @@ static int __init serio_init(void) return error; } - serio_task = kthread_run(serio_thread, NULL, "kseriod"); - if (IS_ERR(serio_task)) { - bus_unregister(&serio_bus); - error = PTR_ERR(serio_task); - pr_err("Failed to start kseriod, error: %d\n", error); - return error; - } - return 0; } static void __exit serio_exit(void) { bus_unregister(&serio_bus); - kthread_stop(serio_task); + + /* + * There should not be any outstanding events but work may + * still be scheduled so simply cancel it. + */ + cancel_work_sync(&serio_event_work); } subsys_initcall(serio_init); -- 2.20.1