Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932068AbZKROm2 (ORCPT ); Wed, 18 Nov 2009 09:42:28 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757529AbZKROm1 (ORCPT ); Wed, 18 Nov 2009 09:42:27 -0500 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:36887 "EHLO bob.linux.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1757526AbZKROm0 (ORCPT ); Wed, 18 Nov 2009 09:42:26 -0500 From: Alan Cox Subject: [PATCH 2/5] tty: Push the lock down further into the ldisc code To: linux-kernel@vger.kernel.org Date: Wed, 18 Nov 2009 14:26:03 +0000 Message-ID: <20091118142548.3806.34931.stgit@localhost.localdomain> In-Reply-To: <20091118142313.3806.47368.stgit@localhost.localdomain> References: <20091118142313.3806.47368.stgit@localhost.localdomain> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1918 Lines: 65 Signed-off-by: Alan Cox --- drivers/char/tty_io.c | 2 -- drivers/char/tty_ldisc.c | 12 +++++++++--- 2 files changed, 9 insertions(+), 5 deletions(-) diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index 05e94a2..a1b1ff6 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -1347,9 +1347,7 @@ struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx, * If we fail here just call release_tty to clean up. No need * to decrement the use counts, as release_tty doesn't care. */ - lock_kernel(); retval = tty_ldisc_setup(tty, tty->link); - unlock_kernel(); if (retval) goto release_mem_out; return tty; diff --git a/drivers/char/tty_ldisc.c b/drivers/char/tty_ldisc.c index d914e77..3f653f7 100644 --- a/drivers/char/tty_ldisc.c +++ b/drivers/char/tty_ldisc.c @@ -445,8 +445,14 @@ static void tty_set_termios_ldisc(struct tty_struct *tty, int num) static int tty_ldisc_open(struct tty_struct *tty, struct tty_ldisc *ld) { WARN_ON(test_and_set_bit(TTY_LDISC_OPEN, &tty->flags)); - if (ld->ops->open) - return ld->ops->open(tty); + if (ld->ops->open) { + int ret; + /* BKL here locks versus a hangup event */ + lock_kernel(); + ret = ld->ops->open(tty); + unlock_kernel(); + return ret; + } return 0; } @@ -566,6 +572,7 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) return 0; } + unlock_kernel(); /* * Problem: What do we do if this blocks ? * We could deadlock here @@ -573,7 +580,6 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) tty_wait_until_sent(tty, 0); - unlock_kernel(); mutex_lock(&tty->ldisc_mutex); /* -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/