static int do_cached_read (struct mtdblk_dev *mtdblk, unsigned long pos, int len, char *buf) { 　… } static int mtdblock_open(struct inode *inode, struct file *file) { 　… } static release_t mtdblock_release(struct inode *inode, struct file *file) { 　int dev; 　struct mtdblk_dev *mtdblk; 　DEBUG(MTD_DEBUG_LEVEL1, "mtdblock_release\n"); 　if (inode == NULL) 　　release_return(-ENODEV); 　dev = minor(inode->i_rdev); 　mtdblk = mtdblks[dev]; 　down(&mtdblk->cache_sem); 　write_cached_data(mtdblk); 　up(&mtdblk->cache_sem); 　spin_lock(&mtdblks_lock); 　if (!--mtdblk->count) { 　　/* It was the last usage. Free the device */ 　　mtdblks[dev] = NULL; 　　spin_unlock(&mtdblks_lock); 　　if (mtdblk->mtd->sync) 　　　mtdblk->mtd->sync(mtdblk->mtd); 　　　put_mtd_device(mtdblk->mtd); 　　　vfree(mtdblk->cache_data); 　　　kfree(mtdblk); 　} else { 　　spin_unlock(&mtdblks_lock); 　} 　DEBUG(MTD_DEBUG_LEVEL1, "ok\n"); 　 　BLK_DEC_USE_COUNT; 　release_return(0); } /* * This is a special request_fn because it is executed in a process context * to be able to sleep independently of the caller. The * io_request_lock (for <2.5) or queue_lock (for >=2.5) is held upon entry * and exit. The head of our request queue is considered active so there is * no need to dequeue requests before we are done. */ static void handle_mtdblock_request(void) { 　struct request *req; 　struct mtdblk_dev *mtdblk; 　unsigned int res; 　for (;;) { 　　INIT_REQUEST; 　　req = CURRENT; 　　spin_unlock_irq(QUEUE_LOCK(QUEUE)); 　　mtdblk = mtdblks[minor(req->rq_dev)]; 　　res = 0;