/*参考drivers/block/xd.c

 *以及drivers/block/z2ram.c

 */

 #include <linux/module.h>

 #include <linux/errno.h>

 #include <linux/interrupt.h>

 #include <linux/mm.h>

 #include <linux/fs.h>

 #include <linux/kernel.h>

 #include <linux/timer.h>

 #include <linux/genhd.h>

 #include <linux/hdreg.h>

 #include <linux/ioport.h>

 #include <linux/init.h>

 #include <linux/wait.h>

 #include <linux/blkdev.h>

 #include <linux/mutex.h>

 #include <linux/blkpg.h>

 #include <linux/delay.h>

 #include <linux/io.h>

 #include <linux/gfp.h>

 #include <asm/uaccess.h>

 #include <asm/dma.h>

 static struct gendisk *ramblock_disk;

 static struct request_queue *ramblock_queue;

 static DEFINE_SPINLOCK(ramblock_lock);

 #define RAMBLOCKSIZE (1024*1024)

 static int major;

 static unsigned char *ramblock;

 static int ramblock_getgeo(struct block_device *bdev, struct hd_geometry *geo)

 {

     geo->heads = ;

     geo->sectors = ;

     geo->cylinders = RAMBLOCKSIZE///;

     return ;

 }

 static const struct block_device_operations ramblock_fops = {

     .owner    = THIS_MODULE,

     .getgeo = ramblock_getgeo,

 };

 static void do_ramblock_request (struct request_queue * q)

 {

       static int cnt = ;

       struct request *req;

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

       req = blk_fetch_request(q);

       while(req){

           unsigned long start = blk_rq_pos(req) << ; //源

         unsigned long len  = blk_rq_cur_bytes(req);  //长度

         /*目的：req->buffer*/

         if (rq_data_dir(req) == READ)

                 memcpy(req->buffer, ramblock+start, len);

             else

                 memcpy(ramblock+start, req->buffer, len);

          if (!__blk_end_request_cur(req, ))

             req = blk_fetch_request(q);

       }

 }

 static int ramblock_init(void)

 {

     ramblock_disk = alloc_disk(); //次设备号个数，分区数+1

     ramblock_queue = blk_init_queue(do_ramblock_request, &ramblock_lock);

     major = register_blkdev(, "ramblock"); // /dev/ramblock

         ramblock_disk->major = major;

         ramblock_disk->first_minor = ;

         sprintf(ramblock_disk->disk_name, "ramblock");

         ramblock_disk->fops = &ramblock_fops;

         ramblock_disk->queue = ramblock_queue;

         set_capacity(ramblock_disk, RAMBLOCKSIZE/);  //设置容量，以扇区512字节为单位

         ramblock = kzalloc(RAMBLOCKSIZE,GFP_KERNEL);

         if(ramblock == NULL){

           printk("alloc ramblock failed!\n");

           return -;

         }

         add_disk(ramblock_disk);

     return ;

 }

 static void ramblock_exit(void)

 {

        del_gendisk(ramblock_disk);

        unregister_blkdev(major,"ramblock");

        blk_cleanup_queue(ramblock_queue);

        put_disk(ramblock_disk);

        kfree(ramblock);

 }

 module_init(ramblock_init);

 module_exit(ramblock_exit);

 MODULE_LICENSE("GPL");

 MODULE_AUTHOR("1653699780@qq.com");