From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934559Ab0EDWgR (ORCPT ); Tue, 4 May 2010 18:36:17 -0400 Received: from moutng.kundenserver.de ([212.227.126.186]:51448 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934525Ab0EDWfQ (ORCPT ); Tue, 4 May 2010 18:35:16 -0400 From: Arnd Bergmann To: linux-kernel@vger.kernel.org Cc: Arnd Bergmann , Alan Cox , Greg KH , Frederic Weisbecker , Thomas Gleixner , Andrew Morton , John Kacur , Al Viro , Ingo Molnar Subject: [PATCH 02/13] tty: make atomic_write_lock release tty_lock Date: Wed, 5 May 2010 00:33:41 +0200 Message-Id: <1273012433-6125-3-git-send-email-arnd@arndb.de> X-Mailer: git-send-email 1.7.0.4 In-Reply-To: <1273012433-6125-1-git-send-email-arnd@arndb.de> References: <1273012433-6125-1-git-send-email-arnd@arndb.de> X-Provags-ID: V01U2FsdGVkX1/Y/qQCgRRrgBKdhfFZ8a1ns1dszwxx7g47YTF XSyTtH9zBkB9baNRhjOpgHrxyKZshIWNkJLdYIJ8gIN26NsXe8 mzZev1AhGYnZ5xlVLvKpQ== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org atomic_write_lock never nests below BTM as far as I can tell, so this can eventually get reverted again unless it triggers bugs. Signed-off-by: Arnd Bergmann --- drivers/char/tty_io.c | 9 +++++++-- 1 files changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index 3bf2c75..8331dd3 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -912,10 +912,15 @@ void tty_write_unlock(struct tty_struct *tty) int tty_write_lock(struct tty_struct *tty, int ndelay) { + /* + * code inspection has shown that this is never called + * with the BTM held. Make sure this stays that way. + */ + WARN_ON_ONCE(tty_locked()); if (!mutex_trylock(&tty->atomic_write_lock)) { if (ndelay) return -EAGAIN; - if (mutex_lock_interruptible(&tty->atomic_write_lock)) + if (mutex_lock_interruptible_tty(&tty->atomic_write_lock)) return -ERESTARTSYS; } return 0; @@ -1024,7 +1029,7 @@ out: void tty_write_message(struct tty_struct *tty, char *msg) { if (tty) { - mutex_lock(&tty->atomic_write_lock); + mutex_lock_tty_off(&tty->atomic_write_lock); tty_lock(); if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) { tty_unlock(); -- 1.7.0.4