On Mon, Aug 17, 2015 at 10:13:53AM +0300, Ruth Glushkin wrote:
> I have a linux kernel driver for serial device, which uses line
> discipline and char device. Driver works with all old kernels,
> starting from 3.8 this driver still works, but when I unload it and
> load again to the memory (modprobe -r bpsctl_mod, after modprobe
> bpsctl_mod), it crashes the kernel. It can't unregister line
> discipline, because this line discipline is busy. I use system device,
> i.e., ttyS0. Here is problematic code:
>
> int init_ebtty_module(void) {
> filp = filp_open("ttyS0", O_RDWR, 0);
> extbp_drv.ebtty_ldisc.magic = TTY_LDISC_MAGIC;
> extbp_drv.ebtty_ldisc.name = BP_LDISC_NAME;
> extbp_drv.ebtty_ldisc.flags = 0;
> extbp_drv.ebtty_ldisc.open = ebtty_open;
> extbp_drv.ebtty_ldisc.close = ebtty_close;
> extbp_drv.ebtty_ldisc.read = NULL;
> extbp_drv.ebtty_ldisc.write = NULL;
> extbp_drv.ebtty_ldisc.ioctl = (int (*)(struct tty_struct *, struct
> file *, unsigned int, unsigned long)) ebtty_ioctl;
> extbp_drv.ebtty_ldisc.poll = NULL;
> extbp_drv.ebtty_ldisc.receive_buf = ebtty_receive_buf;
> extbp_drv.ebtty_ldisc.write_wakeup = NULL;
> status = tty_register_ldisc(extbp_drv.line_disc, &extbp_drv.ebtty_ldisc);
> extbp_drv.ebtty_major = register_chrdev(0, extbp_drv.drv_name, &ebtty_fops);
> if (fd != NULL) {
> bps_vfs_ioctl(fd, TIOCSETD, (unsigned long)&line_disc);
> return 0;
> }
> void exit_ebtty_module(void) {
> if (fd) {
> filp_close(fd, NULL);
> fd = 0;
> }
> if ((status = tty_unregister_ldisc(extbp_drv.line_disc)) != 0)
> err_print(KERN_ERR, DBG_ERROR, ("Can't unregister line discipline (err
> = %d)\n", status));
>
> }
>
> Please advice, maybe I should use something else, instead of line
> discipline and char device, or maybe I should register and unregister
> them other way?
Lots of things have changed in the tty layer in the past few years, do
you have a pointer to the full source code of your driver so we can see
what is needed to convert it all to the new apis?
thanks,
greg k-h
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