>>> On 11/22/2012 at 10:39 AM, in message <[email protected]>, Ilya Zykov <[email protected]> wrote: > 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)
Maybe so, but the patch was there in the first place to resolve an actual observed bug, where a driver would lock up. So the behaviour needs preserved. Andrew -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
