3rd-party/linux-kernel-module-cheat
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bak wait queue

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This commit is contained in:
Ciro Santilli
2017-06-07 08:00:28 +01:00
parent 5c4ae86b89
commit d62826bee2
2 changed files with 92 additions and 2 deletions
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15
kernel_module/wait_queue.c
View File

@@ -3,6 +3,18 @@
if (!cond)
sleep_until_event
Outcome:
1 0
2 0
# Wait one second.
1 1
2 1
# Wait one second.
1 2
2 2
# ...
*/
#include <linux/delay.h> /* usleep_range */
@@ -34,12 +46,11 @@ static int kthread_func1(void *data)
static int kthread_func2(void *data)
{
set_current_state(TASK_INTERRUPTIBLE);
unsigned int i = 0;
while (!kthread_should_stop()) {
pr_info("2 %u\n", i);
i++;
wait_event(queue, atomic_read(&awake));
wait_event_interruptible(queue, atomic_read(&awake));
atomic_set(&awake, 0);
schedule();
}

79
kernel_module/wait_queue2.c Normal file
View File

@@ -0,0 +1,79 @@
/*
Two threads waiting on a single event.
*/
#include <linux/delay.h> /* usleep_range */
#include <linux/kernel.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/wait.h> /* wait_queue_head_t, wait_event_interruptible, wake_up_interruptible */
MODULE_LICENSE("GPL");
static struct task_struct *kthread_wake;
static struct task_struct *kthread_sleep1;
static struct task_struct *kthread_sleep2;
static wait_queue_head_t queue;
static atomic_t awake1 = ATOMIC_INIT(0);
static atomic_t awake2 = ATOMIC_INIT(0);
static int kthread_wake_func(void *data)
{
unsigned int i = 0;
while (!kthread_should_stop()) {
pr_info("0 %u\n", i);
usleep_range(1000000, 1000001);
atomic_set(&awake1, 1);
atomic_set(&awake2, 1);
wake_up(&queue);
i++;
}
i = !i;
wake_up_interruptible(&queue);
return 0;
}
static int kthread_sleep1_func(void *data)
{
unsigned int i = 0;
while (!kthread_should_stop()) {
pr_info("1 %u\n", i);
i++;
wait_event(queue, atomic_read(&awake1));
atomic_set(&awake1, 0);
schedule();
}
return 0;
}
static int kthread_sleep2_func(void *data)
{
unsigned int i = 0;
while (!kthread_should_stop()) {
pr_info("2 %u\n", i);
i++;
wait_event(queue, atomic_read(&awake2));
atomic_set(&awake2, 0);
schedule();
}
return 0;
}
int init_module(void)
{
init_waitqueue_head(&queue);
kthread_wake = kthread_create(kthread_wake_func, NULL, "wake");
kthread_sleep1 = kthread_create(kthread_sleep1_func, NULL, "sleep1");
kthread_sleep2 = kthread_create(kthread_sleep2_func, NULL, "sleep2");
wake_up_process(kthread_wake);
wake_up_process(kthread_sleep1);
wake_up_process(kthread_sleep2);
return 0;
}
void cleanup_module(void)
{
kthread_stop(kthread_wake);
kthread_stop(kthread_sleep1);
kthread_stop(kthread_sleep2);
}