Re: EH method APIs

[Christoph Hellwig <hch@infradead.org>]

On Fri, Apr 04, 2014 at 09:36:54AM +0200, Hannes Reinecke wrote:
> Have to look into this. Problem is that some eh_XXX callback
> implementations actually are using the command to send the TMF;
> will need to look into them how and if they could be changed.

That's indeed a bit of a problem, guess we need to do an audit
on how the commands are used at the moment.

> Actually, alongside with that change I would update the arguments
> to the callback functions to align with the strategy level;
> eh_device_reset() would be getting struct scsi_device as argument,
> eh_target_reset() would get getting struct scsi_target as argument etc.
> 
> So the actual SCSI EH would not be tied to struct scsi_cmnd, and we
> would just be needing something to send TUR etc in the course of
> SCSI EH.

Right.  I think the commands should go through the normal BLOCK_PC code
path, we'd just need to make sure they get priority in the request
allocator.