Date: Wed, 21 Nov 2012 21:30:37 +0000
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Ilya Zykov <ilya@ilyx.ru>
Cc: Andrew McGregor <andrew.mcgregor@alliedtelesis.co.nz>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Alan Cox <alan@linux.intel.com>, linux-kernel@vger.kernel.org,
        linux-serial@vger.kernel.org
Subject: Re: [PATCH] tty: Add driver unthrottle in ioctl(...,TCFLSH,..).
Message-ID: <20121121213037.154306da@pyramind.ukuu.org.uk>
In-Reply-To: <50AD43DB.4030800@ilyx.ru>
References: <50AD43DB.4030800@ilyx.ru>
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> 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
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