Re: [PATCHv4 05/17] pps: access pps device by direct pointer

[Alan Cox]

> Maybe this lock is useless... however, are we sure that before setting
> tty->disc_data to pps its value is null? Otherwise the dcd_change may
> be called with an oops! We cannot control serial port IRQ
> generation... :-/

tty->disc_data is LDISC private. It may be any arbitary value on entry to
the ldisc open method.


> > +	spin_lock_irq(&pps_ldisc_lock);
> > +	tty->disc_data = NULL;
> > +	spin_unlock_irq(&pps_ldisc_lock);

And you don't need to set it to NULL after - some ldiscs do this mostly
as a debug aid.

Alan
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