From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg Kroah-Hartman Subject: [PATCH 30/79] TTY: serial, use ASYNCB_CLOSING in uart_close Date: Wed, 26 Oct 2011 14:12:35 +0200 Message-ID: <1319631204-23262-30-git-send-email-gregkh@suse.de> References: <20111026114236.GA22180@kroah.com> <1319631204-23262-1-git-send-email-gregkh@suse.de> Return-path: Received: from cantor2.suse.de ([195.135.220.15]:60991 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932852Ab1JZMNl (ORCPT ); Wed, 26 Oct 2011 08:13:41 -0400 Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.221.2]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx2.suse.de (Postfix) with ESMTP id 6BA338F71C for ; Wed, 26 Oct 2011 14:13:40 +0200 (CEST) In-Reply-To: <1319631204-23262-1-git-send-email-gregkh@suse.de> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: linux-serial@vger.kernel.org Cc: Jiri Slaby , Greg Kroah-Hartman From: Jiri Slaby We need to move port->mutex locking after wait_until_sent in uart_close (for rationale see next patches). But if we did it now, we would introduce a race between close and open. This is exactly why port->mutex is locked at the top of uart_close. To avoid the race, we add ASYNCB_CLOSING to uart_close. Like every other sane TTY driver. Thanks to tty_port_block_til_ready used in uart_open we will have this for free. Then we can move the port->mutex lock. Also note that this will make the conversion to tty_port helpers easier. They are currently handling ASYNC_CLOSING flag correctly. Signed-off-by: Jiri Slaby Acked-by: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/serial_core.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 3844980..849bd0d 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -1288,6 +1288,7 @@ static void uart_close(struct tty_struct *tty, struct file *filp) * the line discipline to only process XON/XOFF characters by * setting tty->closing. */ + set_bit(ASYNCB_CLOSING, &port->flags); tty->closing = 1; spin_unlock_irqrestore(&port->lock, flags); @@ -1335,8 +1336,10 @@ static void uart_close(struct tty_struct *tty, struct file *filp) * Wake up anyone trying to open this port. */ clear_bit(ASYNCB_NORMAL_ACTIVE, &port->flags); + clear_bit(ASYNCB_CLOSING, &port->flags); spin_unlock_irqrestore(&port->lock, flags); wake_up_interruptible(&port->open_wait); + wake_up_interruptible(&port->close_wait); done: mutex_unlock(&port->mutex); -- 1.7.7