Re: Re: [PATCH] USB changes for 2.5.58

[Oliver Neukum <oliver@neukum.name>]

> > The way this should work is that the LLD calls scsi_remove_device(), and
> > that cuts off the flow of commands.  The LLD can promise to error-out any
> > pending commands in the device command queue.
> >
> > That is, unless scsi_block_requests() and scsi_unblock_requests() are
> > more useful than the documentation suggests... block(), error all
> > commands, unregister()... that would make some sense.  We could call
> > scsi_block_request() as soon as we know the unit is gone, and
> > unregister() as soon as the queue is empty.
>
> We should really ensure that we have good separation between stopping
> device IO, device gone, and release resources.

Very good.

> 	- SCSI seems to have the flags to stop the IO, but instead of
> 	  scsi_block_requests we may want to export the setting of
> 	  device online. This can be done from sysfs now, but

Yes, extremely good, we _need_ this.

> 	  not from the driver ( the driver does have a handle to the
> 	  device, but it would be better to have an interface in case we
> 	  need to do something addition operations).
>
> 	- Possibly add a scsi_remove_device that would always succeed and
> 	  a version of scsi_remove_host that calls scsi_remove_device for
> 	  all devices. Though with the recent change to SCSI remove host to
> 	  allow non sysfs device registration I do not believe we could
> 	  ensure devices would be cleaned up.

Meaning? If memory stays tied up, we have a beautiful DOS attack,
if disconnection can be faked by software.

	Regards
		Oliver



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