Re: [PATCH scsi] Short the path length of scsi_cmd_to_driver()

[Li Zhong <zhong@linux.vnet.ibm.com>]

On Thu, 2012-09-27 at 13:43 -0400, Martin K. Petersen wrote:
> >>>>> "Li" == Li Zhong <zhong@linux.vnet.ibm.com> writes:
> 
> > @@ -845,8 +844,11 @@ static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd,
> > 
> > 	scsi_eh_restore_cmnd(scmd, &ses);
> > 
> >-	if (sdrv && sdrv->eh_action)
> >-		rtn = sdrv->eh_action(scmd, cmnd, cmnd_size, rtn);
> >+	if (scmd->request->cmd_type == REQ_TYPE_FS) {
> >+		struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd);
> >+		if (sdrv->eh_action)
> >+			rtn = sdrv->eh_action(scmd, cmnd, cmnd_size, rtn);
> >+	}
> > 
> > 	return rtn;
> > }
> 
> My only concern is whether our device lifetime rules guarantee that the
> ULD is always attached when we service an error handling command?

Thank you, Martin, for the review. 

I don't know much about scsi, it might take me some more time to have an
answer to the above question. 

For now, if I understand correctly, maybe we could only do the
not-consistent behaviours bug fix?  Or could we provide two versions of
scsi_cmd_to_driver(), one with NULL checking for scsi_send_eh_cmnd(),
one without the checking for scsi_finish_command()? 

Thanks, Zhong