Re: [PATCH] tty: Add driver unthrottle in ioctl(...,TCFLSH,..).

[Ilya Zykov]

On 22.11.2012 1:30, Alan Cox wrote:
> > Function reset_buffer_flags() also invoked during the
> > ioctl(...,TCFLSH,..). At the time of request we can have full buffers
> > and throttled driver too. If we don't unthrottle driver, we can get
> > forever throttled driver, because after request, we will have
> > empty buffers and throttled driver and there is no place to unthrottle driver.
> > It simple reproduce with "pty" pair then one side sleep on tty->write_wait,
> > and other side do ioctl(...,TCFLSH,..). Then there is no place to do writers wake up.
>
>
> So instead of revertng it why not just fix it ? Just add an argument to
> the reset_buffer_flags function to indicate if unthrottling is permitted.
>
> Alan
Because in my opinion, unthrottling permitted always, except release 
last filp (tty->count == 0)

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