一般来说,用户通过fd的传入,调用open系统调用,来获取fd,然后read的时候,通过这个fd来查找对应的file* SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, int, mode) { long ret; if (force_o_largefile()) flags |= O_LARGEFILE; ret = do_sys_open(AT_FDCWD, filename, flags, mode); /*…