epoll/accept睡眠队列学习笔记----实际例子猜想测试验证

1.test.c
#include linux/module.h
#include linux/init.h
#include linux/export.h

static DECLARE_WAIT_QUEUE_HEAD(test_wait);
static wait_queue_head_t * get_wait_queue(void)
{
 return &test_wait;
}
EXPORT_SYMBOL(get_wait_queue);
static int flag = 0;
static int getflag(void)
{
 return flag;
}
EXPORT_SYMBOL(getflag);
static void setflag(int i)
{
 flag = i;
}
EXPORT_SYMBOL(setflag);
static int test_init(void)
{
 printk("do nothing!\n");
 
 return 0;
}
static void test_exit(void)
{
 printk("do nothing!\n");
}

MODULE_AUTHOR("TEST");
MODULE_LICENSE("GPL");
module_init(test_init);
module_exit(test_exit);

2.testa.c
#include linux/module.h
#include linux/init.h
#include linux/sched.h
#include linux/wait.h
#include linux/sched/signal.h

extern void setflag(int i);
extern wait_queue_head_t * get_wait_queue(void);
int i = 0;

static int testb(void)
{
 DECLARE_WAITQUEUE(wait, current);
 
 add_wait_queue(get_wait_queue(), &wait);
 for (;;) {
  __set_current_state(TASK_INTERRUPTIBLE);

  if(i == 1)
   break;
  if (signal_pending(current))
   break;
  schedule();
 }
 remove_wait_queue(get_wait_queue(), &wait);
 set_current_state(TASK_RUNNING);
 return 1;
}
static int testa_init(void)
{
 printk("before testa funcitos!\n");
 testb();
 printk("after testa function");
 return 0;
}
static void testa_exit(void)
{
 i = 1;
 setflag(1);
 wake_up(get_wait_queue());
 printk("testa do nothing!\n");
}

MODULE_AUTHOR("TESTA");
MODULE_LICENSE("GPL");
module_init(testa_init);
module_exit(testa_exit);

2.testb.c
#include linux/module.h
#include linux/init.h
#include linux/sched.h
#include linux/wait.h
#include linux/sched/signal.h

extern int getflag(void);
extern wait_queue_head_t * get_wait_queue(void);

static int testa(void)
{
 DECLARE_WAITQUEUE(wait, current);
 add_wait_queue(get_wait_queue(), &wait);

 for (;;) {
  __set_current_state(TASK_INTERRUPTIBLE);

  if(getflag() == 1)
   break;
  if (signal_pending(current))
   break;
  schedule();
 }
 remove_wait_queue(get_wait_queue(), &wait);
 set_current_state(TASK_RUNNING);
 return 1;
}
static int testb_init(void)
{
 printk("before testb funcitos!\n");
 testa();
 printk("after testb function");
 return 0;
}
static void testb_exit(void)
{
 printk("testb do nothing!\n");
}

MODULE_AUTHOR("TESTB");
MODULE_LICENSE("GPL");
module_init(testb_init);
module_exit(testb_exit);

4.Makefile
ifneq ($(KERNELRELEASE),)
obj-m:=test.o
else
KERNELDIR ?= /lib/modules/$(shell uname -r)/build
PWD := $(shell pwd)
modules:
$(MAKE) -C $(KERNELDIR) M=$(PWD) modules
modules_install:
$(MAKE) -C $(KERNELDIR) M=$(PWD) modules_install
clean:
rm -rf *.o *~ core .depend .*.cmd *.ko *.mod.c .tmp_versions *.symvers *.order *.mod
.PHONY: modules modules_install clean
endif