From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bartlomiej Zolnierkiewicz Subject: Re: [PATCH] ide: ide_port_wait_ready() fix Date: Thu, 13 Oct 2011 19:44:07 +0200 Message-ID: <201110131944.31645.bzolnier@gmail.com> References: <201110121659.55961.bzolnier@gmail.com> <201110131241.04759.bzolnier@gmail.com> <20111013.132527.2221791090526837668.davem@davemloft.net> Mime-Version: 1.0 Content-Type: Text/Plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-bw0-f46.google.com ([209.85.214.46]:39270 "EHLO mail-bw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753831Ab1JMRo6 (ORCPT ); Thu, 13 Oct 2011 13:44:58 -0400 In-Reply-To: <20111013.132527.2221791090526837668.davem@davemloft.net> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: David Miller Cc: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org David Miller wrote: > From: Bartlomiej Zolnierkiewicz > Date: Thu, 13 Oct 2011 12:41:04 +0200 > > > David Miller wrote: > > > >> From: Bartlomiej Zolnierkiewicz > >> Date: Wed, 12 Oct 2011 16:59:55 +0200 > >> > >> > David Miller wrote: > >> > > >> >> From: Bartlomiej Zolnierkiewicz > >> >> Date: Tue, 11 Oct 2011 19:13:18 +0200 > >> >> > >> >> > From: Bartlomiej Zolnierkiewicz > >> >> > Subject: [PATCH] ide: ide_port_wait_ready() fix > >> >> > > >> >> > Fix for commit a20b2a4 ("ide: skip probe if there are no devices on > >> >> > the port (v2)"). We must check for slave device before failing. > >> >> > > >> >> > Signed-off-by: Bartlomiej Zolnierkiewicz > >> >> > >> >> This will mishandle the case where there is no slave in the device > >> >> list. > >> > > >> > I don't see it: > >> > > >> > @ -598,7 +598,7 @@ static int ide_port_wait_ready(ide_hwif_ > >> > { > >> > const struct ide_tp_ops *tp_ops = hwif->tp_ops; > >> > ide_drive_t *drive; > >> > - int i, rc; > >> > + int i, rc, prev_rc = 0; > >> > > >> > printk(KERN_DEBUG "Probing IDE interface %s...\n", hwif->name); > >> > > >> > @@ -623,8 +623,10 @@ static int ide_port_wait_ready(ide_hwif_ > >> > tp_ops->write_devctl(hwif, ATA_DEVCTL_OBS); > >> > mdelay(2); > >> > rc = ide_wait_not_busy(hwif, 35000); > >> > - if (rc) > >> > + if (prev_rc && rc) > >> > goto out; > >> > + prev_rc = rc; > >> > + rc = 0; > >> > } else > >> > printk(KERN_DEBUG "%s: ide_wait_not_busy() skipped\n", > >> > drive->name); > >> > > >> > If there is no slave device but there is a master device the code falls-through > >> > and returns a success. > >> > >> That's not what we want, if there is only a master device and no slave device > >> in the list this loop is iterating over we want to return the error code > >> in "rc", not zero. > > > > No, we want to return zero (success) since at least once device was found > > (otherwise we fail probe on some esoteric setups returning -ENODEV from > > ide_wait_not_busy() for master device). > > > > This is how this function worked before commit a20b2a4 if you want something > > else okay but it needs to work with aforementioned setups. > > You unconditionally assign "prev_rc = rc" and set "rc = 0" so if we only run > the loop once, we return zero. > > And we do this even if that one device gave a non-zero return value. > > That's not what we want. Here is revised patch: From: Bartlomiej Zolnierkiewicz Subject: [PATCH v2] ide: ide_port_wait_ready() fix Fix for commit a20b2a4 ("ide: skip probe if there are no devices on the port (v2)"). We must check for slave device before failing. Signed-off-by: Bartlomiej Zolnierkiewicz --- drivers/ide/ide-probe.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) Index: b/drivers/ide/ide-probe.c =================================================================== --- a/drivers/ide/ide-probe.c +++ b/drivers/ide/ide-probe.c @@ -598,7 +598,7 @@ static int ide_port_wait_ready(ide_hwif_ { const struct ide_tp_ops *tp_ops = hwif->tp_ops; ide_drive_t *drive; - int i, rc; + int i, rc, prev_rc = 0; printk(KERN_DEBUG "Probing IDE interface %s...\n", hwif->name); @@ -623,8 +623,9 @@ static int ide_port_wait_ready(ide_hwif_ tp_ops->write_devctl(hwif, ATA_DEVCTL_OBS); mdelay(2); rc = ide_wait_not_busy(hwif, 35000); - if (rc) + if (prev_rc && rc) goto out; + prev_rc = rc; } else printk(KERN_DEBUG "%s: ide_wait_not_busy() skipped\n", drive->name);