On Tue, Jan 13, 2009 at 03:02:27PM +0100, Hannes Reinecke wrote:
> Matthew Wilcox wrote:
> >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);
> I must say I don't really like the for(;;) construct.
I'd be fine with:
do {
sdev = __scsi_device_lookup_by_target(starget, sdev, lun);
} while (sdev && scsi_device_get(sdev));
though I find that slightly less clear than the for (;;) construct.
> And it's really confusing as we want to find an sdev, so breaking
> if it's _not_ found is ... weird.
Those are the two conditions when we want to stop trying -- if there's
no device or if the device we've found is bad. I can definitely see an
argument for splitting the two conditions to make that more obvious. I
can also see an argument for not returning an sdev in the _DEL state
from __scsi_device_lookup_by_target in the first place.
--
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."
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