From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Hurley Subject: [PATCH v2 tty-next 6/8] n_tty: Only perform wakeups for waiters Date: Mon, 2 Dec 2013 14:24:46 -0500 Message-ID: <1386012288-5079-7-git-send-email-peter@hurleysoftware.com> References: <1385135965-4235-1-git-send-email-peter@hurleysoftware.com> <1386012288-5079-1-git-send-email-peter@hurleysoftware.com> Return-path: Received: from mailout02.c08.mtsvc.net ([205.186.168.190]:44392 "EHLO mailout02.c08.mtsvc.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755394Ab3LBTZx (ORCPT ); Mon, 2 Dec 2013 14:25:53 -0500 In-Reply-To: <1386012288-5079-1-git-send-email-peter@hurleysoftware.com> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Greg Kroah-Hartman Cc: Jiri Slaby , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, One Thousand Gnomes , Peter Hurley Only wakeup the _waiting_ reader, polls and/or writer(s). Signed-off-by: Peter Hurley --- drivers/tty/n_tty.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index aae171e..5254082 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -275,7 +275,8 @@ static void n_tty_check_unthrottle(struct tty_struct *tty) return; n_tty_set_room(tty); n_tty_write_wakeup(tty->link); - wake_up_interruptible_poll(&tty->link->write_wait, POLLOUT); + if (waitqueue_active(&tty->link->write_wait)) + wake_up_interruptible_poll(&tty->link->write_wait, POLLOUT); return; } @@ -350,7 +351,8 @@ static void n_tty_packet_mode_flush(struct tty_struct *tty) spin_lock_irqsave(&tty->ctrl_lock, flags); if (tty->link->packet) { tty->ctrl_status |= TIOCPKT_FLUSHREAD; - wake_up_interruptible(&tty->link->read_wait); + if (waitqueue_active(&tty->link->read_wait)) + wake_up_interruptible(&tty->link->read_wait); } spin_unlock_irqrestore(&tty->ctrl_lock, flags); } @@ -1158,7 +1160,8 @@ static void n_tty_receive_break(struct tty_struct *tty) put_tty_queue('\0', ldata); } put_tty_queue('\0', ldata); - wake_up_interruptible(&tty->read_wait); + if (waitqueue_active(&tty->read_wait)) + wake_up_interruptible(&tty->read_wait); } /** @@ -1216,7 +1219,8 @@ static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c) put_tty_queue('\0', ldata); else put_tty_queue(c, ldata); - wake_up_interruptible(&tty->read_wait); + if (waitqueue_active(&tty->read_wait)) + wake_up_interruptible(&tty->read_wait); } static void @@ -1811,8 +1815,10 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) start_tty(tty); /* The termios change make the tty ready for I/O */ - wake_up_interruptible(&tty->write_wait); - wake_up_interruptible(&tty->read_wait); + if (waitqueue_active(&tty->write_wait)) + wake_up_interruptible(&tty->write_wait); + if (waitqueue_active(&tty->read_wait)) + wake_up_interruptible(&tty->read_wait); } /** -- 1.8.1.2