struct hd_geometry_geometry dash_typedef struct(2)

{

static int r_cnt = 0;

static int w_cnt = 0;

struct request *req;

//printk("do_ramblock_request %d\n", ++cnt);

while ((req = elv_next_request(q)) != NULL) {

/* 数据传输三要素: 源,目的,长度 */

/* 源/目的: */

unsigned long offset = req->sector * 512;//偏移值为

/* 目的/源: */

// req->buffer

/* 长度: */

unsigned long len = req->current_nr_sectors * 512;

if (rq_data_dir(req) == READ)

{

//printk("do_ramblock_request read %d\n", ++r_cnt);

memcpy(req->buffer, ramblock_buf+offset, len);

}

else

{

//printk("do_ramblock_request write %d\n", ++w_cnt);

memcpy(ramblock_buf+offset, req->buffer, len);

}

end_request(req, 1);//表示读写完成，必须写，不然会卡在那里，只有重新开关机

}

}

}

static void ramblock_exit(void)

{

unregister_blkdev(major, "ramblock");

del_gendisk(ramblock_disk);

put_disk(ramblock_disk);

blk_cleanup_queue(ramblock_queue);

kfree(ramblock_buf);

}

测试如下：

在开发板上:

1. insmod ramblock.ko

2. 格式化: mkdosfs /dev/ramblock

3. 挂接: mount /dev/ramblock /tmp/

4. 读写文件: cd /tmp, 在里面vi文件

5. cd /; umount /tmp/

6. cat /dev/ramblock > /mnt/ramblock.bin

7. 在PC上查看ramblock.bin

sudo mount -o loop ramblock.bin /mnt

测试5th:

1. insmod ramblock.ko

2. ls /dev/ramblock*

3. fdisk /dev/ramblock

块设备常用的几个命令：

m：寻求帮助 n：增加一个新的分区 w:保存分区

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