From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759222Ab1KWA6K (ORCPT ); Tue, 22 Nov 2011 19:58:10 -0500 Received: from cantor2.suse.de ([195.135.220.15]:42368 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932479Ab1KWAfR (ORCPT ); Tue, 22 Nov 2011 19:35:17 -0500 X-Mailbox-Line: From gregkh@clark.kroah.org Tue Nov 22 16:25:55 2011 Message-Id: <20111123002555.070455211@clark.kroah.org> User-Agent: quilt/0.48-20.1.2 Date: Tue, 22 Nov 2011 16:25:23 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Jiri Slaby , Dave Young , Dave Jones , Ben Hutchings , Dmitriy Matrosov Subject: [23/53] TTY: ldisc, allow waiting for ldisc arbitrarily long In-Reply-To: <20111123002601.GA14467@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiri Slaby commit df92d0561de364de53c42abc5d43e04ab6f326a5 upstream. To fix a nasty bug in ldisc hup vs. reinit we need to wait infinitely long for ldisc to be gone. So here we add a parameter to tty_ldisc_wait_idle to allow that. This is only a preparation for the real fix which is done in the following patches. Signed-off-by: Jiri Slaby Cc: Dave Young Cc: Dave Jones Cc: Ben Hutchings Cc: Dmitriy Matrosov Cc: Alan Cox Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_ldisc.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) --- a/drivers/tty/tty_ldisc.c +++ b/drivers/tty/tty_ldisc.c @@ -548,15 +548,16 @@ static void tty_ldisc_flush_works(struct /** * tty_ldisc_wait_idle - wait for the ldisc to become idle * @tty: tty to wait for + * @timeout: for how long to wait at most * * Wait for the line discipline to become idle. The discipline must * have been halted for this to guarantee it remains idle. */ -static int tty_ldisc_wait_idle(struct tty_struct *tty) +static int tty_ldisc_wait_idle(struct tty_struct *tty, long timeout) { - int ret; + long ret; ret = wait_event_timeout(tty_ldisc_idle, - atomic_read(&tty->ldisc->users) == 1, 5 * HZ); + atomic_read(&tty->ldisc->users) == 1, timeout); if (ret < 0) return ret; return ret > 0 ? 0 : -EBUSY; @@ -666,7 +667,7 @@ int tty_set_ldisc(struct tty_struct *tty tty_ldisc_flush_works(tty); - retval = tty_ldisc_wait_idle(tty); + retval = tty_ldisc_wait_idle(tty, 5 * HZ); tty_lock(); mutex_lock(&tty->ldisc_mutex); @@ -763,7 +764,7 @@ static int tty_ldisc_reinit(struct tty_s if (IS_ERR(ld)) return -1; - WARN_ON_ONCE(tty_ldisc_wait_idle(tty)); + WARN_ON_ONCE(tty_ldisc_wait_idle(tty, 5 * HZ)); tty_ldisc_close(tty, tty->ldisc); tty_ldisc_put(tty->ldisc);