From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Hurley Subject: [PATCH -next v2 01/26] tty: Don't hold tty_lock for ldisc release Date: Wed, 5 Nov 2014 12:12:44 -0500 Message-ID: <1415207589-15967-2-git-send-email-peter@hurleysoftware.com> References: <1413491125-20134-1-git-send-email-peter@hurleysoftware.com> <1415207589-15967-1-git-send-email-peter@hurleysoftware.com> Return-path: Received: from mailout32.mail01.mtsvc.net ([216.70.64.70]:50480 "EHLO n23.mail01.mtsvc.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755309AbaKERNb (ORCPT ); Wed, 5 Nov 2014 12:13:31 -0500 In-Reply-To: <1415207589-15967-1-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 , One Thousand Gnomes , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, Peter Hurley The tty->ldisc_sem write lock is sufficient for serializing changes to tty->ldisc; holding the tty lock is not required. Reviewed-by: Alan Cox Signed-off-by: Peter Hurley --- drivers/tty/tty_ldisc.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c index 2d822aa..332a622 100644 --- a/drivers/tty/tty_ldisc.c +++ b/drivers/tty/tty_ldisc.c @@ -764,6 +764,8 @@ static void tty_ldisc_kill(struct tty_struct *tty) * Called during the final close of a tty/pty pair in order to shut down * the line discpline layer. On exit the ldisc assigned is N_TTY and the * ldisc has not been opened. + * + * Holding ldisc_sem write lock serializes tty->ldisc changes. */ void tty_ldisc_release(struct tty_struct *tty, struct tty_struct *o_tty) @@ -776,13 +778,9 @@ void tty_ldisc_release(struct tty_struct *tty, struct tty_struct *o_tty) tty_ldisc_debug(tty, "closing ldisc: %p\n", tty->ldisc); tty_ldisc_lock_pair(tty, o_tty); - tty_lock_pair(tty, o_tty); - tty_ldisc_kill(tty); if (o_tty) tty_ldisc_kill(o_tty); - - tty_unlock_pair(tty, o_tty); tty_ldisc_unlock_pair(tty, o_tty); /* And the memory resources remaining (buffers, termios) will be -- 2.1.3