Re: [PATCH 03/31] Protect SCSI device state changes with a mutex

Hannes Reinecke
2017-05-24T05:51:13Z

On 05/24/2017 02:33 AM, Bart Van Assche wrote:
> Enable this mechanism for all scsi_target_*block() callers but not
> for the scsi_internal_device_unblock() calls from the mpt3sas driver
> because that driver can call scsi_internal_device_unblock() from
> atomic context.
>
> Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Hannes Reinecke <hare@suse.com>
> Cc: Johannes Thumshirn <jthumshirn@suse.de>
> ---
> drivers/scsi/scsi_error.c | 8 +++++++-
> drivers/scsi/scsi_lib.c | 27 +++++++++++++++++++++------
> drivers/scsi/scsi_scan.c | 16 +++++++++-------
> drivers/scsi/scsi_sysfs.c | 24 +++++++++++++++++++-----
> drivers/scsi/scsi_transport_srp.c | 7 ++++---
> drivers/scsi/sd.c | 7 +++++--
> include/scsi/scsi_device.h | 1 +
> 7 files changed, 66 insertions(+), 24 deletions(-)
>
[ .. ]
> diff --git a/drivers/scsi/scsi_transport_srp.c b/drivers/scsi/scsi_transport_srp.c
> index 3c5d89852e9f..f617021c94f7 100644
> --- a/drivers/scsi/scsi_transport_srp.c
> +++ b/drivers/scsi/scsi_transport_srp.c
> @@ -554,11 +554,12 @@ int srp_reconnect_rport(struct srp_rport *rport)
> * invoking scsi_target_unblock() won't change the state of
> * these devices into running so do that explicitly.
> */
> - spin_lock_irq(shost->host_lock);
> - __shost_for_each_device(sdev, shost)
> + shost_for_each_device(sdev, shost) {
> + mutex_lock(&sdev->state_mutex);
> if (sdev->sdev_state == SDEV_OFFLINE)
> sdev->sdev_state = SDEV_RUNNING;
> - spin_unlock_irq(shost->host_lock);
> + mutex_unlock(&sdev->state_mutex);
> + }
> } else if (rport->state == SRP_RPORT_RUNNING) {
> /*
> * srp_reconnect_rport() has been invoked with fast_io_fail
Why do you drop the host lock here? I thought that the host lock is
needed to protect shost_for_each_device()?

Cheers,

Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@suse.de +49 911 74053 688
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