3rd-party/linux-kernel-module-cheat
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Move poll, ktrhead and kthreads docs to README

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Ciro Santilli
2018-07-01 20:01:49 +01:00
parent ae3c03bdb0
commit 2075fbaf5b
6 changed files with 490 additions and 407 deletions
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3
kernel_module/README.adoc
View File

@@ -20,11 +20,8 @@
... link:dep2.c[]
. Pseudo filesystems
.. link:mmap.c[]
.. link:poll.c[]
. Asynchronous
.. link:irq.c[]
.. link:kthread.c[]
.. link:kthreads.c[]
.. link:schedule.c[]
.. link:sleep.c[]
.. link:timer.c[]

15
kernel_module/kthread.c
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@@ -1,13 +1,4 @@
/*
Kernel threads are managed exactly like userland threads.
They also have a backing task_struct, and are scheduled with the same mechanism.
See also:
- http://stackoverflow.com/questions/10177641/proper-way-of-handling-threads-in-kernel
- http://stackoverflow.com/questions/4084708/how-to-wait-for-a-linux-kernel-thread-kthreadto-exit
*/
/* https://github.com/cirosantilli/linux-kernel-module-cheat#kthread */
#include <linux/delay.h> /* usleep_range */
#include <linux/kernel.h>
@@ -18,9 +9,9 @@ static struct task_struct *kthread;
static int work_func(void *data)
{
int i = 0;
u32 i = 0;
while (!kthread_should_stop()) {
pr_info("%d\n", i);
pr_info("%u\n", i);
usleep_range(1000000, 1000001);
i++;
if (i == 10)

4
kernel_module/kthreads.c
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@@ -1,6 +1,4 @@
/*
2 kthreads!!! Will they interleave??? Yup.
*/
/* https://github.com/cirosantilli/linux-kernel-module-cheat#kthreads */
#include <linux/delay.h> /* usleep_range */
#include <linux/kernel.h>

17
kernel_module/poll.c
View File

@@ -1,10 +1,4 @@
/*
/poll.sh
Outcome: user echoes jiffies every second.
https://stackoverflow.com/questions/30035776/how-to-add-poll-function-to-the-kernel-module-code/44645336#44645336
*/
/* https://github.com/cirosantilli/linux-kernel-module-cheat#poll */
#include <linux/debugfs.h>
#include <linux/delay.h> /* usleep_range */
@@ -40,11 +34,10 @@ static ssize_t read(struct file *filp, char __user *buf, size_t len, loff_t *off
return ret;
}
/*
If you return 0 here, then the kernel will sleep until an event happens in the queue.
This gets called again every time an event happens in the wait queue.
*/
/* If you return 0 here, then the kernel will sleep until an event happens in the queue.
*
* This gets called again every time an event happens in the wait queue.
*/
unsigned int poll(struct file *filp, struct poll_table_struct *wait)
{
poll_wait(filp, &waitqueue, wait);