【Tiny6410 And Linux】—（5.1）—RamDisk 驱动实现（内核缺省的处理函数 __make_request()）——代码

电脑总算是修好了！

但是 JBL 音响又 TMD 出了问题！

真心不逗！

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1、驱动程序

 

①、blk.c

#include <linux/module.h>#include <linux/moduleparam.h>#include <linux/init.h>#include <linux/sched.h>#include <linux/kernel.h>/* printk() */#include <linux/slab.h>/* kmalloc() */#include <linux/fs.h>/* everything... */#include <linux/errno.h>/* error codes */#include <linux/timer.h>#include <linux/types.h>/* size_t */#include <linux/fcntl.h>/* O_ACCMODE */#include <linux/hdreg.h>/* HDIO_GETGEO */#include <linux/kdev_t.h>#include <linux/vmalloc.h>#include <linux/genhd.h>#include <linux/blkdev.h>#include <linux/buffer_head.h>/* invalidate_bdev */#include <linux/bio.h>#include <linux/major.h>#include <linux/version.h>#define SIMP_BLKDEV_DEVICEMAJORCOMPAQ_SMART2_MAJOR#define SIMP_BLKDEV_DISKNAME        "_Justin"#define SIMP_BLKDEV_BYTES        (16 * 1024 * 1024)static struct request_queue *simp_blkdev_queue;static struct gendisk *simp_blkdev_disk;unsigned char simp_blkdev_data[SIMP_BLKDEV_BYTES];/* * simp_blkdev_make_request */static int simp_blkdev_make_request(struct request_queue *q, struct bio *bio){struct request *req;/* 在 2.6.38 的内核没有这个函数，那又要怎么调用 * 还有就是 struct request 的变量差距好大！ */while((req = elv_next_request(q)) != NULL){if((req->sector + req->current_nr_sectors) << 9> SIMP_BLKDEV_BYTES){printk(KERN_ERR SIMP_BLKDEV_DISKNAME": bad request: block = %llu, count = %u\n",(unsigned long long)req->sector,req->current_nr_sectors);end_request(req, 0);continue;}/*  * rq_data_dir 是一个 macro！ * #define rq_data_dir(rq) ((rq)->cmd_flags & 1) */switch(rq_data_dir(req)){case READ:memcpy(req->buffer,simp_blkdev_data + (req->sector << 9),req->current_nr_sectors << 9);end_request(req, 1);break;case WRITE:memcpy(simp_blkdev_data + (req->sector << 9),req->buffer,req->current_nr_sectors << 9);end_request(req, 1);break;default:/* No default because rq_data_dir(req) 1 bit */break;}}}/*  * block_device_operations */struct block_device_operations simp_blkdev_fops = {        .owner = THIS_MODULE,};/*  * simp_blkdev_init */static int __init simp_blkdev_init(void){        int ret;/* 初始化请求队列 */        simp_blkdev_queue = blk_init_queue(simp_blkdev_make_request,NULL);        if(!simp_blkdev_queue) {                ret = -ENOMEM;                goto err_init_queue;        }/* 分配一个 gendisk 结构 */        simp_blkdev_disk = alloc_disk(1);        if (!simp_blkdev_disk) {                ret = -ENOMEM;                goto err_alloc_disk;        }/* 填充 gendisk 主要结构成员 */        strcpy(simp_blkdev_disk->disk_name, SIMP_BLKDEV_DISKNAME);        simp_blkdev_disk->major = SIMP_BLKDEV_DEVICEMAJOR;        simp_blkdev_disk->first_minor = 0;        simp_blkdev_disk->fops = &simp_blkdev_fops;        simp_blkdev_disk->queue = simp_blkdev_queue;/* 设置容量，其实说白了就是一个转换 */        set_capacity(simp_blkdev_disk, SIMP_BLKDEV_BYTES >> 9);/* 向内核注册块设备驱动 */        add_disk(simp_blkdev_disk);        return 0;err_alloc_disk:        blk_cleanup_queue(simp_blkdev_queue);err_init_queue:        return ret;}/*  * simp_blkdev_exit */static void __exit simp_blkdev_exit(void){        del_gendisk(simp_blkdev_disk);/* 删除 gendisk 结构 */        put_disk(simp_blkdev_disk);/* 释放一个该对象的引用 */        blk_cleanup_queue(simp_blkdev_queue);/* 清理请求队列 */}module_init(simp_blkdev_init);module_exit(simp_blkdev_exit);

②、Makefile

这里一定要注意了：

这是基于 X86 平台的驱动，所以跟基于 ARM 平台的驱动是有区别的，主要是编译器和平台不一样！

 

ifneq ($(KERNELRELEASE),)obj-m := blk.oelseKDIR := /lib/modules/2.6.27.62/buildall:make -C $(KDIR) M=$(PWD) modulesclean:rm -f *.ko *.o *.mod.o *.mod.c *.symvers *.orderendif

2、实验结果

 

通过以下步骤来实现！

1) insmod blk.ko

2) mkdir -p /mnt/blk

3) mkfs.ext3 /dev/_Justin

4) mount /dev/_Justin /mnt/blk

5) ls /mnt/dev/

6) umount /mnt/dev

7) rmmod blk

 

如图所示：