Int cdrom_open(struct inode*ip, struct file*fp)

This function is not called directly by the low-level drivers, it is listed in the standard cdrom_fops. If the VFS opens a file, this function becomes active. A strategy logic is implemented in this routine, taking care of all capabilities and options that are set in the cdrom_device_ops connected to the device. Then, the program flow is transferred to the device_dependent open() call.