在Linux内核模块中设置动态变量

包括#include< linux / moduleparam.h>在内核模块中.

使用module_param()变量和module_param_array()将数组传递给内核模块.

请参阅如何将值传递给模块Passing an array as command line argument for linux kernel module

这是module_param()的示例程序

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>

#include "MyHeader.h"

int a = 0,b = 0,op = 0;


module_param(a,int,S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
module_param(b,S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
module_param(op,S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);

int __init init_module(void)
{
  printk("n Second Module Loaded...... n");

  if((a == 0) && (b == 0) && (op == 0))
  {     
         printk("n Supply Module Parameters...... n");
         printk("n insmod <modulename>.ko op=<1-4> a=<int data> b=<int data> n");
         return 0;
  }

 switch(op)
  {
    case 1:
         printk("n Result of Addition:%d n",add(a,b));
         break;
    case 2:
         printk("n Result of Subtraction:%d n",sub(a,b));
         break;
    case 3:
         printk("n Result of Multiplication:%d n",mul(a,b));
         break;
    case 4:
         printk("n Result of Division:%d n",div(a,b));
         break;
    default:
         printk("n Unknown Operation... n");
  }

  return 0;
}

void cleanup_module()
{
  printk("n Second Module UN--Loaded...... n");
}

另一个将数组传递给内核模块的示例.

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>

int a[5];
int count;
module_param_array(a,&count,0);

int init_module(void)
{

    int i = 0;
    printk("n Welcome to sample kernel module n");

    for(i = 0; i < count; i++)
    {
       printk("na[%d] = %d",i,a[i]);
    }

    return 0;

}

void cleanup_module()
{
     printk("n Exit success n");
}

除了模块参数之外,还在以下链接中提出了其他替代方案.
http://kernelnewbies.org/FAQ/WhyWritingFilesFromKernelIsBad