From c44f242064093e640a068741b05ee6acdd49bc22 Mon Sep 17 00:00:00 2001 From: Dmitry Torokhov Date: Mon, 15 Nov 2010 01:39:57 -0800 Subject: [PATCH] Input: gameport - convert to use common workqueue instead of a thread Instead of creating an exclusive thread to handle gameport events (which happen rarely), let's switch to 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/gameport/gameport.c | 152 +++++++++++++----------------- 1 file changed, 68 insertions(+), 84 deletions(-) diff --git a/drivers/input/gameport/gameport.c b/drivers/input/gameport/gameport.c index 46239e47a260..dbf741c95835 100644 --- a/drivers/input/gameport/gameport.c +++ b/drivers/input/gameport/gameport.c @@ -18,13 +18,11 @@ #include #include #include -#include #include #include -#include +#include #include /* HZ */ #include -#include /*#include */ @@ -234,58 +232,22 @@ struct gameport_event { static DEFINE_SPINLOCK(gameport_event_lock); /* protects gameport_event_list */ static LIST_HEAD(gameport_event_list); -static DECLARE_WAIT_QUEUE_HEAD(gameport_wait); -static struct task_struct *gameport_task; -static int gameport_queue_event(void *object, struct module *owner, - enum gameport_event_type event_type) +static struct gameport_event *gameport_get_event(void) { + struct gameport_event *event = NULL; unsigned long flags; - struct gameport_event *event; - int retval = 0; spin_lock_irqsave(&gameport_event_lock, flags); - /* - * Scan event list for the other events for the same gameport 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, &gameport_event_list, node) { - if (event->object == object) { - if (event->type == event_type) - goto out; - break; - } - } - - event = kmalloc(sizeof(struct gameport_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(&gameport_event_list)) { + event = list_first_entry(&gameport_event_list, + struct gameport_event, node); + list_del_init(&event->node); } - event->type = event_type; - event->object = object; - event->owner = owner; - - list_add_tail(&event->node, &gameport_event_list); - wake_up(&gameport_wait); - -out: spin_unlock_irqrestore(&gameport_event_lock, flags); - return retval; + return event; } static void gameport_free_event(struct gameport_event *event) @@ -319,24 +281,8 @@ static void gameport_remove_duplicate_events(struct gameport_event *event) spin_unlock_irqrestore(&gameport_event_lock, flags); } -static struct gameport_event *gameport_get_event(void) -{ - struct gameport_event *event = NULL; - unsigned long flags; - - spin_lock_irqsave(&gameport_event_lock, flags); - - if (!list_empty(&gameport_event_list)) { - event = list_first_entry(&gameport_event_list, - struct gameport_event, node); - list_del_init(&event->node); - } - - spin_unlock_irqrestore(&gameport_event_lock, flags); - return event; -} -static void gameport_handle_event(void) +static void gameport_handle_events(struct work_struct *work) { struct gameport_event *event; @@ -368,6 +314,59 @@ static void gameport_handle_event(void) mutex_unlock(&gameport_mutex); } +static DECLARE_WORK(gameport_event_work, gameport_handle_events); + +static int gameport_queue_event(void *object, struct module *owner, + enum gameport_event_type event_type) +{ + unsigned long flags; + struct gameport_event *event; + int retval = 0; + + spin_lock_irqsave(&gameport_event_lock, flags); + + /* + * Scan event list for the other events for the same gameport 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 preserve sequence of distinct events. + */ + list_for_each_entry_reverse(event, &gameport_event_list, node) { + if (event->object == object) { + if (event->type == event_type) + goto out; + break; + } + } + + event = kmalloc(sizeof(struct gameport_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, &gameport_event_list); + schedule_work(&gameport_event_work); + +out: + spin_unlock_irqrestore(&gameport_event_lock, flags); + return retval; +} + /* * Remove all events that have been submitted for a given object, * be it a gameport port or a driver. @@ -419,19 +418,6 @@ static struct gameport *gameport_get_pending_child(struct gameport *parent) return child; } -static int gameport_thread(void *nothing) -{ - set_freezable(); - do { - gameport_handle_event(); - wait_event_freezable(gameport_wait, - kthread_should_stop() || !list_empty(&gameport_event_list)); - } while (!kthread_should_stop()); - - return 0; -} - - /* * Gameport port operations */ @@ -814,13 +800,6 @@ static int __init gameport_init(void) return error; } - gameport_task = kthread_run(gameport_thread, NULL, "kgameportd"); - if (IS_ERR(gameport_task)) { - bus_unregister(&gameport_bus); - error = PTR_ERR(gameport_task); - pr_err("Failed to start kgameportd, error: %d\n", error); - return error; - } return 0; } @@ -828,7 +807,12 @@ static int __init gameport_init(void) static void __exit gameport_exit(void) { bus_unregister(&gameport_bus); - kthread_stop(gameport_task); + + /* + * There should not be any outstanding events but work may + * still be scheduled so simply cancel it. + */ + cancel_work_sync(&gameport_event_work); } subsys_initcall(gameport_init); -- 2.20.1