From: Arnd Bergmann <arnd@arndb•de>
To: linuxppc-dev@lists•ozlabs.org
Cc: One Thousand Gnomes <gnomes@lxorguk•ukuu.org.uk>,
Karsten Keil <isdn@linux-pingi•de>,
Peter Hurley <peter@hurleysoftware•com>,
Greg Kroah-Hartman <gregkh@linuxfoundation•org>,
linux-kernel@vger•kernel.org, linux-serial@vger•kernel.org
Subject: Re: [PATCH tty-next 14/22] tty: Remove tty_wait_until_sent_from_close()
Date: Tue, 17 Jun 2014 10:00:59 +0200 [thread overview]
Message-ID: <4575870.N9RCpZ4UMg@wuerfel> (raw)
In-Reply-To: <1402924639-5164-15-git-send-email-peter@hurleysoftware.com>
On Monday 16 June 2014 09:17:11 Peter Hurley wrote:
> tty_wait_until_sent_from_close() drops the tty lock while waiting
> for the tty driver to finish sending previously accepted data (ie.,
> data remaining in its write buffer and transmit fifo).
>
> However, dropping the tty lock is a hold-over from when the tty
> lock was system-wide; ie., one lock for all ttys.
>
> Since commit 89c8d91e31f267703e365593f6bfebb9f6d2ad01,
> 'tty: localise the lock', dropping the tty lock has not been necessary.
>
> CC: Karsten Keil <isdn@linux-pingi•de>
> CC: linuxppc-dev@lists•ozlabs.org
> Signed-off-by: Peter Hurley <peter@hurleysoftware•com>
I don't understand the second half of the changelog, it doesn't seem
to fit here: there deadlock that we are trying to avoid here happens
when the *same* tty needs the lock to complete the function that
sends the pending data. I don't think we do still do that any more,
but it doesn't seem related to the tty lock being system-wide or not.
Arnd
next prev parent reply other threads:[~2014-06-17 8:01 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1402924639-5164-1-git-send-email-peter@hurleysoftware.com>
2014-06-16 13:17 ` [PATCH tty-next 14/22] tty: Remove tty_wait_until_sent_from_close() Peter Hurley
2014-06-17 8:00 ` Arnd Bergmann [this message]
2014-06-17 8:18 ` David Laight
2014-06-17 10:57 ` Peter Hurley
2014-06-17 11:03 ` David Laight
2014-06-17 11:31 ` Arnd Bergmann
2014-06-17 11:54 ` One Thousand Gnomes
2014-06-17 11:32 ` Peter Hurley
2014-07-09 13:57 ` Peter Hurley
2014-10-08 3:56 ` Peter Hurley
2014-10-10 8:58 ` One Thousand Gnomes
2014-07-10 23:09 ` Greg Kroah-Hartman
2014-07-11 15:03 ` Peter Hurley
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