From: Hannes Reinecke <hare@suse.de>
To: Bart Van Assche <bvanassche@acm.org>
Cc: James Bottomley <jbottomley@parallels.com>,
Mike Christie <michaelc@cs.wisc.edu>,
Chanho Min <chanho.min@lge.com>, Joe Lawrence <jdl1291@gmail.com>,
linux-scsi <linux-scsi@vger.kernel.org>,
David Milburn <dmilburn@redhat.com>, Tejun Heo <tj@kernel.org>
Subject: Re: [PATCH v12 6/6] Avoid re-enabling I/O after the transport became offline
Date: Mon, 01 Jul 2013 10:27:56 +0200 [thread overview]
Message-ID: <51D13D8C.9070407@suse.de> (raw)
In-Reply-To: <51CC52EB.9040900@acm.org>
On 06/27/2013 04:57 PM, Bart Van Assche wrote:
> Disallow the SDEV_TRANSPORT_OFFLINE to SDEV_CANCEL transition such
> that no I/O is sent to devices for which the transport is offline.
> Notes:
> - Functions like sd_shutdown() use scsi_execute_req() and hence
> set the REQ_PREEMPT flag. Such requests are passed to the LLD
> queuecommand callback in the SDEV_CANCEL state.
> - This patch does not affect Fibre Channel LLD drivers since these
> drivers invoke fc_remote_port_chkready() before submitting a SCSI
> request to the HBA. That prevents a timeout to occur in state
> SDEV_CANCEL if the transport is offline.
>
> Signed-off-by: Bart Van Assche <bvanassche@acm.org>
> Cc: Mike Christie <michaelc@cs.wisc.edu>
> Cc: James Bottomley <JBottomley@Parallels.com>
> Cc: Hannes Reinecke <hare@suse.de>
> Cc: Tejun Heo <tj@kernel.org>
> ---
> drivers/scsi/scsi_lib.c | 1 -
> drivers/scsi/scsi_sysfs.c | 4 +++-
> 2 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index 6a4fde7..63875c3 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -2180,7 +2180,6 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
> case SDEV_RUNNING:
> case SDEV_QUIESCE:
> case SDEV_OFFLINE:
> - case SDEV_TRANSPORT_OFFLINE:
> case SDEV_BLOCK:
> break;
> default:
> diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
> index dfbaa34..666b741 100644
> --- a/drivers/scsi/scsi_sysfs.c
> +++ b/drivers/scsi/scsi_sysfs.c
> @@ -959,14 +959,16 @@ void __scsi_remove_device(struct scsi_device *sdev)
> {
> struct Scsi_Host *shost = sdev->host;
> struct device *dev = &sdev->sdev_gendev;
> + enum scsi_device_state sdev_state;
> int res;
>
> if (sdev->is_visible) {
> spin_lock_irq(shost->host_lock);
> + sdev_state = sdev->sdev_state;
> res = scsi_device_set_state(sdev, SDEV_CANCEL);
> spin_unlock_irq(shost->host_lock);
>
> - if (res != 0)
> + if (res != 0 && sdev_state != SDEV_TRANSPORT_OFFLINE)
> return;
>
> bsg_unregister_queue(sdev->request_queue);
>
Hmm. This is really subtle. Do you mind adding inserting a comment
here on why this is required?
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@suse.de +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
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next prev parent reply other threads:[~2013-07-01 8:27 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-27 14:51 [PATCH v12 0/6] SCSI device removal fixes Bart Van Assche
2013-06-27 14:52 ` [PATCH v12 1/6] Fix race between starved list and device removal Bart Van Assche
2013-06-27 14:53 ` [PATCH v12 2/6] Avoid calling __scsi_remove_device() twice Bart Van Assche
2013-07-01 7:05 ` James Bottomley
2013-07-01 7:14 ` Bart Van Assche
2013-07-01 14:38 ` James Bottomley
2013-06-27 14:54 ` [PATCH v12 3/6] Restrict device state changes allowed via sysfs Bart Van Assche
2013-07-01 8:23 ` Hannes Reinecke
2013-07-01 14:51 ` James Bottomley
2013-06-27 14:55 ` [PATCH v12 4/6] Avoid saving/restoring interrupt state inside scsi_remove_host() Bart Van Assche
2013-06-27 14:56 ` [PATCH v12 5/6] Avoid that scsi_device_set_state() triggers a race Bart Van Assche
2013-07-01 14:49 ` James Bottomley
2013-07-01 15:17 ` Bart Van Assche
2013-07-01 16:52 ` James Bottomley
2013-07-02 6:42 ` Bart Van Assche
2013-06-27 14:57 ` [PATCH v12 6/6] Avoid re-enabling I/O after the transport became offline Bart Van Assche
2013-07-01 8:27 ` Hannes Reinecke [this message]
2013-07-01 12:05 ` Bart Van Assche
2013-07-01 12:09 ` Hannes Reinecke
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