1. 根目录:
2. fs
3. read_write.h

/*
 * This file is only for sharing some helpers from read_write.c with compat.c.
 * Don't use anywhere else.
 */


typedef ssize_t (*io_fn_t)(struct file *, char __user *, size_t, loff_t *);
typedef ssize_t (*iov_fn_t)(struct kiocb *, const struct iovec *,
		unsigned long, loff_t);

ssize_t do_sync_readv_writev(struct file *filp, const struct iovec *iov,
		unsigned long nr_segs, size_t len, loff_t *ppos, iov_fn_t fn);
ssize_t do_loop_readv_writev(struct file *filp, struct iovec *iov,
		unsigned long nr_segs, loff_t *ppos, io_fn_t fn);