Re: [PATCH 1/3] SCSI: Introduce device_lock and target_lock in Scsi_Host

[Hannes Reinecke <hare@suse.de>]

On 10/14/2015 03:50 PM, Johannes Thumshirn wrote:
> Introduce target_lock and device_lock to untangle the __devices and __targets
> lists from the host_lock.
> 
> Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
> ---
>  drivers/scsi/53c700.c     |  3 +++
>  drivers/scsi/hosts.c      |  2 ++
>  drivers/scsi/scsi.c       |  8 ++++----
>  drivers/scsi/scsi_scan.c  | 10 +++++-----
>  drivers/scsi/scsi_sysfs.c | 18 ++++++++----------
>  include/scsi/scsi_host.h  |  2 ++
>  6 files changed, 24 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/scsi/53c700.c b/drivers/scsi/53c700.c
> index a209c34..e2b4d04 100644
> --- a/drivers/scsi/53c700.c
> +++ b/drivers/scsi/53c700.c
> @@ -1093,6 +1093,7 @@ process_script_interrupt(__u32 dsps, __u32 dsp, struct scsi_cmnd *SCp,
>  		struct NCR_700_command_slot *slot;
>  		__u8 reselection_id = hostdata->reselection_id;
>  		struct scsi_device *SDp;
> +		unsigned long flags;
>  
>  		lun = hostdata->msgin[0] & 0x1f;
>  
> @@ -1100,7 +1101,9 @@ process_script_interrupt(__u32 dsps, __u32 dsp, struct scsi_cmnd *SCp,
>  		DEBUG(("scsi%d: (%d:%d) RESELECTED!\n",
>  		       host->host_no, reselection_id, lun));
>  		/* clear the reselection indicator */
> +		spin_lock_irqsave(host->device_lock, flags);
>  		SDp = __scsi_device_lookup(host, 0, reselection_id, lun);
> +		spin_unlock_irqrestore(host->device_lock, flags);
>  		if(unlikely(SDp == NULL)) {
>  			printk(KERN_ERR "scsi%d: (%d:%d) HAS NO device\n",
>  			       host->host_no, reselection_id, lun);

Hmm. Unfortunate.

Can't we get rid of the underscore version altogether, seeing that
we have our own lock now?

Cheers,

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