case WRITE:
　　　　// Read only device
　　　　if ( !(mtdblk->mtd->flags & MTD_WRITEABLE) )
　　　　　break;
　　　　　// Do the write
　　　　　down(&mtdblk->cache_sem);
　　　　　err = do_cached_write (mtdblk, req->sector << 9,req->current_nr_sectors << 9, req->buffer);
　　　　　up(&mtdblk->cache_sem);
　　　　if (!err)
　　　　　res = 1;
　　　　　break;
　　}

　　end_req:
　　　spin_lock_irq(QUEUE_LOCK(QUEUE));
　　　end_request(res);
　}
}

int __init init_mtdblock(void)
{
　int i;

　spin_lock_init(&mtdblks_lock);
　/* this lock is used just in kernels >= 2.5.x */
　spin_lock_init(&mtdblock_lock);

　#ifdef CONFIG_DEVFS_FS
　if (devfs_register_blkdev(MTD_BLOCK_MAJOR, DEVICE_NAME, &mtd_fops))
　{
　　printk(KERN_NOTICE "Can't allocate major number %d for Memory Technology Devices.\n",MTD_BLOCK_MAJOR);
　　return -EAGAIN;
　}

　devfs_dir_handle = devfs_mk_dir(NULL, DEVICE_NAME, NULL);
　register_mtd_user(&notifier);
　#else
　if (register_blkdev(MAJOR_NR,DEVICE_NAME,&mtd_fops)) {
　　printk(KERN_NOTICE "Can't allocate major number %d for Memory Technology Devices.\n",MTD_BLOCK_MAJOR);
　　return -EAGAIN;
　}
　#endif

　/* We fill it in at open() time. */
　for (i=0; i< MAX_MTD_DEVICES; i++) {
　　mtd_sizes[i] = 0;
　　mtd_blksizes[i] = BLOCK_SIZE;
　}
　init_waitqueue_head(&thr_wq);
　/* Allow the block size to default to BLOCK_SIZE. */
　blksize_size[MAJOR_NR] = mtd_blksizes;
　blk_size[MAJOR_NR] = mtd_sizes;

　BLK_INIT_QUEUE(BLK_DEFAULT_QUEUE(MAJOR_NR), &mtdblock_request, &mtdblock_lock);

　kernel_thread (mtdblock_thread, NULL, CLONE_FS|CLONE_FILES|CLONE_SIGHAND);
　return 0;
}

static void __exit cleanup_mtdblock(void)
{
　leaving = 1;
　wake_up(&thr_wq);
　down(&thread_sem);
　#ifdef CONFIG_DEVFS_FS
　　unregister_mtd_user(&notifier);
　　devfs_unregister(devfs_dir_handle);
　　devfs_unregister_blkdev(MTD_BLOCK_MAJOR, DEVICE_NAME);
　#else
　　unregister_blkdev(MAJOR_NR,DEVICE_NAME);
　#endif
　blk_cleanup_queue(BLK_DEFAULT_QUEUE(MAJOR_NR));
　blksize_size[MAJOR_NR] = NULL;
　blk_size[MAJOR_NR] = NULL;
}