Hi Matthew,
Matthew Wilcox wrote:
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.
Opinons differ.
Something for the maintainer to decide. James?
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.
Not sure if that would work with esp_scsi.c (the other user of
__scsi_device_lookup_by_target()).
And don't have a device to try it with.
But modifying __scsi_device_lookup_by_target() would alter the behaviour,
whereas this patch does not.
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@xxxxxxx +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Markus Rex, HRB 16746 (AG Nürnberg)
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