From: Ilya Zykov <ilya@ilyx.ru>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-kernel@vger.kernel.org,
Andrew McGregor <andrew.mcgregor@alliedtelesis.co.nz>
Subject: Re: [PATCH] tty: Add driver unthrottle in ioctl(...,TCFLSH,..).
Date: Thu, 22 Nov 2012 01:55:46 +0400 [thread overview]
Message-ID: <50AD4DE2.7080002@ilyx.ru> (raw)
In-Reply-To: <20121121213037.154306da@pyramind.ukuu.org.uk>
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
>
Maybe we don't need call reset_buffer_flags() then execute tty_release()
and (tty->count != 0)? Why in this case we reset buffers?
next prev parent reply other threads:[~2012-11-22 18:30 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-21 21:12 [PATCH] tty: Add driver unthrottle in ioctl(...,TCFLSH,..) Ilya Zykov
2012-11-21 21:30 ` Alan Cox
2012-11-21 21:39 ` Ilya Zykov
2012-11-22 0:47 ` andrew mcgregor
2012-11-22 4:29 ` Ilya Zykov
2012-11-22 5:25 ` andrew mcgregor
2012-11-22 6:35 ` Ilya Zykov
2012-11-22 6:03 ` Ilya Zykov
2012-11-22 6:16 ` Ilya Zykov
2012-11-21 21:55 ` Ilya Zykov [this message]
2012-11-27 6:14 [PATCH v4] " Ilya Zykov
2012-11-27 17:24 ` Greg Kroah-Hartman
2012-11-27 18:46 ` Ilya Zykov
2012-11-27 19:32 ` Alan Cox
2013-01-16 9:07 ` [PATCH] " Ilya Zykov
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