From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757170AbYAZQoR (ORCPT ); Sat, 26 Jan 2008 11:44:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752962AbYAZQoD (ORCPT ); Sat, 26 Jan 2008 11:44:03 -0500 Received: from einhorn.in-berlin.de ([192.109.42.8]:58196 "EHLO einhorn.in-berlin.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752532AbYAZQoB (ORCPT ); Sat, 26 Jan 2008 11:44:01 -0500 X-Envelope-From: stefanr@s5r6.in-berlin.de Date: Sat, 26 Jan 2008 17:43:23 +0100 (CET) From: Stefan Richter Subject: [PATCH 2/3] firewire: fw-sbp2: fix logout before login retry To: linux1394-devel@lists.sourceforge.net cc: Jarod Wilson , =?iso-8859-1?Q?Kristian_H=F8gsberg?= , linux-kernel@vger.kernel.org In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; CHARSET=us-ascii Content-Disposition: INLINE Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This fixes a "can't recognize device" kind of bug. If the SCSI INQUIRY failed and hence __scsi_add_device failed due to a bus reset, we tried a logout and then waited for the already scheduled login work to happen. So far so good, but the generation used for the logout was outdated, hence the logout never reached the target. The target might therefore deny the subsequent relogin attempt, which would also leave the target inaccessible. Therefore fetch a fresh device->generation for the logout. Use memory barriers to prevent our plan being foiled by compiler or hardware optimizations. Signed-off-by: Stefan Richter --- drivers/firewire/fw-sbp2.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) Index: linux/drivers/firewire/fw-sbp2.c =================================================================== --- linux.orig/drivers/firewire/fw-sbp2.c +++ linux/drivers/firewire/fw-sbp2.c @@ -716,7 +716,11 @@ static void sbp2_login(struct work_struc sdev = __scsi_add_device(shost, 0, 0, scsilun_to_int(&eight_bytes_lun), lu); if (IS_ERR(sdev)) { - sbp2_send_management_orb(lu, node_id, generation, + smp_rmb(); /* generation may have changed */ + generation = device->generation; + smp_rmb(); /* node_id must not be older than generation */ + + sbp2_send_management_orb(lu, device->node_id, generation, SBP2_LOGOUT_REQUEST, lu->login_id, NULL); /* * Set this back to sbp2_login so we fall back and -- Stefan Richter -=====-==--- ---= ==-=- http://arcgraph.de/sr/