Re: [PATCH]: libata-scsi: Don't start hotplug work queue if hotplug is disabled

[Chunbo Luo <chunbo.luo@windriver.com>]

On Fri, 2008-07-18 at 22:33 +0900, Tejun Heo wrote:
> Chunbo Luo wrote:
> > Hi
> > 
> > When ata_scsi_scan_host() scan device failed, it will start a work queue
> > unconditionally. This may cause some noisy messages. This patch fix this
> > problem.
> 
> ATA_PFLAG_SCSI_HOTPLUG doesn't mean that hotplug is enabled.  It
> indicates that EH needs to schedule a kick at SCSI's ass and make it
> scan for discovered devices && work running on ata_aux_wq testing it
> doesn't mean anything.  There's no synchronization.
> 
> >     Previously, queue_delayed_work() was started unconditionally, but if
> >     ATA_PFLAG_SCSI_HOTPLUG is not set and we do this, the work queue may
> >     cause multiple messages like this:
> >     
> >     ata3.00: WARNING: ATAPI is not supported with this driver, device ignored.
> 
> And this message has nothing to do with SCSI.  It's printed by libata
> proper for several drivers which don't support ATAPI.  Did the patch
> really kill the warning messages?  Can you please post full boot log
> from 2.6.26 w/o the patch?

If the drivers don't support ATAPI, the hotplug task cannot find linked device,
and it will start the hotplug task again. Which will print messages continously 
like this.

----------
ata3.00: WARNING: ATAPI is not supported with this driver, device ignored.
ata3.00: WARNING: ATAPI is not supported with this driver, device ignored.
ata3.00: WARNING: ATAPI is not supported with this driver, device ignored.
ata3.00: WARNING: ATAPI is not supported with this driver, device ignored.
...
------------

We should find a way to avoid this kind of noisy warning messages.

This patch cannot kill the warning messages, but it can avoid the
duplicate warning messages.




> 
> Andrew, please drop the patch from -mm.  Thanks.
>