Commit 8ee294cd authored by Dmitry Torokhov's avatar Dmitry Torokhov

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: default avatarDmitry Torokhov <dtor@mail.ru>
parent ce16a474
...@@ -32,10 +32,9 @@ ...@@ -32,10 +32,9 @@
#include <linux/module.h> #include <linux/module.h>
#include <linux/serio.h> #include <linux/serio.h>
#include <linux/errno.h> #include <linux/errno.h>
#include <linux/wait.h>
#include <linux/sched.h> #include <linux/sched.h>
#include <linux/slab.h> #include <linux/slab.h>
#include <linux/kthread.h> #include <linux/workqueue.h>
#include <linux/mutex.h> #include <linux/mutex.h>
MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>"); MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
...@@ -44,7 +43,7 @@ MODULE_LICENSE("GPL"); ...@@ -44,7 +43,7 @@ MODULE_LICENSE("GPL");
/* /*
* serio_mutex protects entire serio subsystem and is taken every time * 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); static DEFINE_MUTEX(serio_mutex);
...@@ -165,58 +164,22 @@ struct serio_event { ...@@ -165,58 +164,22 @@ struct serio_event {
static DEFINE_SPINLOCK(serio_event_lock); /* protects serio_event_list */ static DEFINE_SPINLOCK(serio_event_lock); /* protects serio_event_list */
static LIST_HEAD(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, static struct serio_event *serio_get_event(void)
enum serio_event_type event_type)
{ {
struct serio_event *event = NULL;
unsigned long flags; unsigned long flags;
struct serio_event *event;
int retval = 0;
spin_lock_irqsave(&serio_event_lock, flags); spin_lock_irqsave(&serio_event_lock, flags);
/* if (!list_empty(&serio_event_list)) {
* Scan event list for the other events for the same serio port, event = list_first_entry(&serio_event_list,
* starting with the most recent one. If event is the same we struct serio_event, node);
* do not need add new one. If event is of different type we list_del_init(&event->node);
* 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);
wake_up(&serio_wait);
out:
spin_unlock_irqrestore(&serio_event_lock, flags); spin_unlock_irqrestore(&serio_event_lock, flags);
return retval; return event;
} }
static void serio_free_event(struct serio_event *event) static void serio_free_event(struct serio_event *event)
...@@ -250,25 +213,7 @@ static void serio_remove_duplicate_events(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); spin_unlock_irqrestore(&serio_event_lock, flags);
} }
static void serio_handle_event(struct work_struct *work)
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)
{ {
struct serio_event *event; struct serio_event *event;
...@@ -307,6 +252,59 @@ static void serio_handle_event(void) ...@@ -307,6 +252,59 @@ static void serio_handle_event(void)
mutex_unlock(&serio_mutex); 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 * Remove all events that have been submitted for a given
* object, be it serio port or driver. * object, be it serio port or driver.
...@@ -356,18 +354,6 @@ static struct serio *serio_get_pending_child(struct serio *parent) ...@@ -356,18 +354,6 @@ static struct serio *serio_get_pending_child(struct serio *parent)
return child; 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 * Serio port operations
*/ */
...@@ -1040,21 +1026,18 @@ static int __init serio_init(void) ...@@ -1040,21 +1026,18 @@ static int __init serio_init(void)
return error; 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; return 0;
} }
static void __exit serio_exit(void) static void __exit serio_exit(void)
{ {
bus_unregister(&serio_bus); 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); subsys_initcall(serio_init);
......
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