Re: [PATCH] Restart scsi_device_lookup_by_target

[Matthew Wilcox <matthew@wil.cx>]

On Tue, Jan 13, 2009 at 02:50:30PM +0100, Hannes Reinecke wrote:
> @@ -1131,14 +1137,15 @@ EXPORT_SYMBOL(__scsi_device_lookup_by_target);
>  struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
>  						 uint lun)
>  {
> -	struct scsi_device *sdev;
> +	struct scsi_device *sdev = NULL;
>  	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
>  	unsigned long flags;
>  
>  	spin_lock_irqsave(shost->host_lock, flags);
> -	sdev = __scsi_device_lookup_by_target(starget, lun);
> + restart:
> +	sdev = __scsi_device_lookup_by_target(starget, sdev, lun);
>  	if (sdev && scsi_device_get(sdev))
> -		sdev = NULL;
> +		goto restart;
>  	spin_unlock_irqrestore(shost->host_lock, flags);
>  
>  	return sdev;

Backwards jumps are generally disapproved of.  How about:

	spin_lock_irqsave(shost->host_lock, flags);
	for (;;) {
		sdev = __scsi_device_lookup_by_target(starget, sdev, lun);
		if (!sdev || !scsi_device_get(sdev))
			break;
	}
	spin_unlock_irqrestore(shost->host_lock, flags);


-- 
Matthew Wilcox				Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours.  We can't possibly take such
a retrograde step."