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authorDmitry Torokhov <dmitry.torokhov@gmail.com>2010-11-15 01:39:57 -0800
committerDmitry Torokhov <dmitry.torokhov@gmail.com>2010-11-18 00:25:45 -0800
commit8ee294cd9def0004887da7f44b80563493b0a097 (patch)
treeb1c7ff0136fa2c359fdf6898a185921dd5a5db92 /drivers/input/serio/serio.c
parentce16a474f6305dd631c885ba970d5746e4d5c803 (diff)
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 <dtor@mail.ru>
Diffstat (limited to 'drivers/input/serio/serio.c')
-rw-r--r--drivers/input/serio/serio.c155
1 files 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 <linux/module.h>
#include <linux/serio.h>
#include <linux/errno.h>
-#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/slab.h>
-#include <linux/kthread.h>
+#include <linux/workqueue.h>
#include <linux/mutex.h>
MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
@@ -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);