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

From: James Bottomley
Date: Fri Sep 28 2012 - 03:45:28 EST


On Thu, 2012-09-27 at 13:43 -0400, Martin K. Petersen wrote:
> >>>>> "Li" == Li Zhong <zhong@xxxxxxxxxxxxxxxxxx> 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?

Yes, they are. We can only get REQ_TYPE_FS through a filesystem, which
must be mounted on a block device, which is provided by the ULD. You
can't unmount with outstanding I/O (which people complain about when it
goes into error handling, I'll admit), so the ULD has to stay bound.

James



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