linux内核嵌入、

Question

#include <linux/fs.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/vmalloc.h>
#include <linux/blkdev.h>
#include <linux/genhd.h>
#include <linux/errno.h>
#include <linux/hdreg.h>
#include <linux/version.h>

#define MY_DEVICE_NAME "myramdisk"

static int mybdrv_ma_no, diskmb = 256, disk_size;
static char *ramdisk;
static struct gendisk *my_gd;
static spinlock_t lock;
static unsigned short sector_size = 512;
static struct request_queue *my_request_queue;

module_param_named(size, diskmb, int, 0);

static void my_request(struct request_queue *q)
{
    struct request *rq;
    int size, res = 0;
    char *ptr;
    unsigned nr_sectors, sector;
    pr_info("start handle request\n");

    rq = blk_fetch_request(q); // 从请求队列中拉一个request出来
    while (rq)
    {
        nr_sectors = blk_rq_cur_sectors(rq);   // 这个请求需要多少个sector
        sector = blk_rq_pos(rq);
        ptr = ramdisk + sector * sector_size;
        size = nr_sectors * sector_size;

        if ((ptr + size) > (ramdisk + disk_size))
        {
            pr_err("end of device\n");
            goto done;
        }

        if (rq_data_dir(rq))
        {
            pr_info("writing at sector %d, %u sectors\n",
                    sector, nr_sectors);
            memcpy(ptr, bio_data(rq->bio), size);
        }
        else
        {
            pr_info("reading at sector %d, %u sectors\n",
                    sector, nr_sectors);
            memcpy(bio_data(rq->bio), ptr, size);
        }

    done:
        if (!blk_end_request(rq, res, size))
            rq = blk_fetch_request(q);
    }
    pr_info("handle request done\n");
}

static int my_ioctl(struct block_device *bdev, fmode_t mode,
                    unsigned int cmd, unsigned long arg)
{
    long size;
    struct hd_geometry geo;

    pr_info("cmd=%d\n", cmd);

    switch (cmd)
    {
    case HDIO_GETGEO:
        pr_info("HIT HDIO_GETGEO\n");
        size = disk_size;
        size &= ~0x3f;
        geo.cylinders = size >> 6;
        geo.heads = 2;
        geo.sectors = 16;
        geo.start = 4;

        if (copy_to_user((void __user *)arg, &geo, sizeof(geo)))
            return -EFAULT;

        return 0;
    }
    pr_warn("return -ENOTTY\n");

    return -ENOTTY;
}

static const struct block_device_operations mybdrv_fops = {
    .owner = THIS_MODULE,
    .ioctl = my_ioctl,
};

static int __init my_init(void)
{
    disk_size = diskmb * 1024 * 1024;
    spin_lock_init(&lock);

    ramdisk = vmalloc(disk_size);
    if (!ramdisk)
        return -ENOMEM;

    my_request_queue = blk_init_queue(my_request, &lock);
    if (!my_request_queue)
    {
        vfree(ramdisk);
        return -ENOMEM;
    }
    blk_queue_logical_block_size(my_request_queue, sector_size);

    mybdrv_ma_no = register_blkdev(0, MY_DEVICE_NAME);
    if (mybdrv_ma_no < 0)
    {
        pr_err("Failed registering mybdrv, returned %d\n",
               mybdrv_ma_no);
        vfree(ramdisk);
        return mybdrv_ma_no;
    }

    my_gd = blk_alloc_disk(GFP_KERNEL);
    if (!my_gd)
    {
        unregister_blkdev(mybdrv_ma_no, MY_DEVICE_NAME);
        vfree(ramdisk);
        return -ENOMEM;
    }

    my_gd->major = mybdrv_ma_no;
    my_gd->first_minor = 0;
    my_gd->fops = &mybdrv_fops;
    strcpy(my_gd->disk_name, MY_DEVICE_NAME);
    my_gd->queue = my_request_queue;
    set_capacity(my_gd, disk_size / sector_size);

    add_disk(my_gd);

    pr_info("device successfully registered, Major No. = %d\n",
            mybdrv_ma_no);
    pr_info("Capacity of ram disk is: %d MB\n", diskmb);

    return 0;
}

static void __exit my_exit(void)
{
    del_gendisk(my_gd);
    put_disk(my_gd);
    unregister_blkdev(mybdrv_ma_no, MY_DEVICE_NAME);
    pr_info("module successfully unloaded, Major No. = %d\n", mybdrv_ma_no);
    blk_cleanup_queue(my_request_queue);
    vfree(ramdisk);
}

module_init(my_init);
module_exit(my_exit);

MODULE_AUTHOR("Benshushu");
MODULE_LICENSE("GPL v2");

Makefile文件

CONFIG_MODULE_SIG=n
PWD := $(shell pwd)
obj-m += ramdisk_driver.o
all : 
    make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules
 
install:
    make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules_install;
    
    
 
clean:
    make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean
    rm -f *.ko;

一直报错，有没有知道如何解决呀

报错为
sudo make
make -C /lib/modules/5.15.0-91-generic/build M=/home/dream/code modules
make[1]: Entering directory '/usr/src/linux-headers-5.15.0-91-generic'
  CC [M]  /home/dream/code/ramdisk_driver.o
/home/dream/code/ramdisk_driver.c: In function ‘my_request’:
/home/dream/code/ramdisk_driver.c:32:11: error: implicit declaration of function ‘blk_mq_dequeue’ [-Werror=implicit-function-declaration]
   32 |      rq = blk_mq_dequeue(q); // 从请求队列中拉一个request出来
      |           ^~~~~~~~~~~~~~
/home/dream/code/ramdisk_driver.c:32:9: warning: assignment to ‘struct request *’ from ‘int’ makes pointer from integer without a cast [-Wint-conversion]
   32 |      rq = blk_mq_dequeue(q); // 从请求队列中拉一个request出来
      |         ^
/home/dream/code/ramdisk_driver.c:61:14: error: implicit declaration of function ‘blk_end_request_cur’; did you mean ‘blk_get_request’? [-Werror=implicit-function-declaration]
   61 |         if (!blk_end_request_cur(rq, res))
      |              ^~~~~~~~~~~~~~~~~~~
      |              blk_get_request
/home/dream/code/ramdisk_driver.c:62:18: error: implicit declaration of function ‘blk_fetch_request’; did you mean ‘blk_get_request’? [-Werror=implicit-function-declaration]
   62 |             rq = blk_fetch_request(q);
      |                  ^~~~~~~~~~~~~~~~~
      |                  blk_get_request
/home/dream/code/ramdisk_driver.c:62:16: warning: assignment to ‘struct request *’ from ‘int’ makes pointer from integer without a cast [-Wint-conversion]
   62 |             rq = blk_fetch_request(q);
      |                ^
/home/dream/code/ramdisk_driver.c: In function ‘my_init’:
/home/dream/code/ramdisk_driver.c:113:24: error: implicit declaration of function ‘blk_init_queue’; did you mean ‘blk_put_queue’? [-Werror=implicit-function-declaration]
  113 |     my_request_queue = blk_init_queue(my_request, &lock);  // 初始化请求队列，第一个参数是函数指针
      |                        ^~~~~~~~~~~~~~
      |                        blk_put_queue
/home/dream/code/ramdisk_driver.c:113:22: warning: assignment to ‘struct request_queue *’ from ‘int’ makes pointer from integer without a cast [-Wint-conversion]
  113 |     my_request_queue = blk_init_queue(my_request, &lock);  // 初始化请求队列，第一个参数是函数指针
      |                      ^
/home/dream/code/ramdisk_driver.c:130:13: error: implicit declaration of function ‘blk_mq_alloc_disk’; did you mean ‘blk_alloc_disk’? [-Werror=implicit-function-declaration]
  130 |     my_gd = blk_mq_alloc_disk(my_request_queue, NULL);   // 分配一个gendisk
      |             ^~~~~~~~~~~~~~~~~
      |             blk_alloc_disk
/home/dream/code/ramdisk_driver.c:130:11: warning: assignment to ‘struct gendisk *’ from ‘int’ makes pointer from integer without a cast [-Wint-conversion]
  130 |     my_gd = blk_mq_alloc_disk(my_request_queue, NULL);   // 分配一个gendisk
      |           ^
cc1: some warnings being treated as errors
make[2]: *** [scripts/Makefile.build:297: /home/dream/code/ramdisk_driver.o] Error 1
make[1]: *** [Makefile:1909: /home/dream/code] Error 2
make[1]: Leaving directory '/usr/src/linux-headers-5.15.0-91-generic'
make: *** [Makefile:5: all] Error 2
dream@ubuntu:~/code$ ^C
dream@ubuntu:~/code$ sudo make clean
make -C /lib/modules/5.15.0-91-generic/build M=/home/dream/code clean
make[1]: Entering directory '/usr/src/linux-headers-5.15.0-91-generic'
make[1]: Leaving directory '/usr/src/linux-headers-5.15.0-91-generic'
rm -f *.ko;
dream@ubuntu:~/code$ sudo make
make -C /lib/modules/5.15.0-91-generic/build M=/home/dream/code modules
make[1]: Entering directory '/usr/src/linux-headers-5.15.0-91-generic'
  CC [M]  /home/dream/code/ramdisk_driver.o
/home/dream/code/ramdisk_driver.c: In function ‘my_request’:
/home/dream/code/ramdisk_driver.c:31:10: error: implicit declaration of function ‘blk_fetch_request’; did you mean ‘blk_get_request’? [-Werror=implicit-function-declaration]
   31 |     rq = blk_fetch_request(q); // 从请求队列中拉一个request出来
      |          ^~~~~~~~~~~~~~~~~
      |          blk_get_request
/home/dream/code/ramdisk_driver.c:31:8: warning: assignment to ‘struct request *’ from ‘int’ makes pointer from integer without a cast [-Wint-conversion]
   31 |     rq = blk_fetch_request(q); // 从请求队列中拉一个request出来
      |        ^
/home/dream/code/ramdisk_driver.c:59:14: error: implicit declaration of function ‘blk_end_request’; did you mean ‘blk_get_request’? [-Werror=implicit-function-declaration]
   59 |         if (!blk_end_request(rq, res, size))
      |              ^~~~~~~~~~~~~~~
      |              blk_get_request
/home/dream/code/ramdisk_driver.c:60:16: warning: assignment to ‘struct request *’ from ‘int’ makes pointer from integer without a cast [-Wint-conversion]
   60 |             rq = blk_fetch_request(q);
      |                ^
/home/dream/code/ramdisk_driver.c: In function ‘my_init’:
/home/dream/code/ramdisk_driver.c:108:24: error: implicit declaration of function ‘blk_init_queue’; did you mean ‘blk_put_queue’? [-Werror=implicit-function-declaration]
  108 |     my_request_queue = blk_init_queue(my_request, &lock);
      |                        ^~~~~~~~~~~~~~
      |                        blk_put_queue
/home/dream/code/ramdisk_driver.c:108:22: warning: assignment to ‘struct request_queue *’ from ‘int’ makes pointer from integer without a cast [-Wint-conversion]
  108 |     my_request_queue = blk_init_queue(my_request, &lock);
      |                      ^
cc1: some warnings being treated as errors
make[2]: *** [scripts/Makefile.build:297: /home/dream/code/ramdisk_driver.o] Error 1
make[1]: *** [Makefile:1909: /home/dream/code] Error 2
make[1]: Leaving directory '/usr/src/linux-headers-5.15.0-91-generic'
make: *** [Makefile:5: all] Error 2

Answer 1

【相关推荐】

• 帮你找了个相似的问题, 你可以看下: https://ask.csdn.net/questions/1104745
• 我还给你找了一篇非常好的博客，你可以看看是否有帮助，链接：linux下使用Makefile编译程序入门介绍
• 您还可以看一下 王利涛老师的Linux Makefile工程实战视频教程课程中的 2.3 变量小节, 巩固相关知识点
  
• 除此之外, 这篇博客: Linux基础——makefile编写中的 Makefile基本原则和原理 部分也许能够解决你的问题, 你可以仔细阅读以下内容或跳转源博客中阅读:
  

  makefile中的三要素：目标、依赖、命令
  

  目标：要生成的目标文件（在Makefile中会把第一个目标作为终极目标，一切以生成终极目标为最终目的）
  依赖：生成目标文件需要的一些文件
  命令：借助依赖文件生成目标文件的手段

  

  工作原理：要生成终极目标，先检查依赖条件是否都具备，如果有依赖条件不存才则再寻找新的规则来生成依赖条件

如果你已经解决了该问题, 非常希望你能够分享一下解决方案, 写成博客, 将相关链接放在评论区, 以帮助更多的人 ^-^