[dm-devel] Re: [PATCH RFC 0/4] use scatter lists for all block pc requests and simplify hw handlers

[Jens Axboe]

On Wed, Jun 08 2005, Patrick Mansfield wrote:
> On Wed, Jun 08, 2005 at 10:41:48AM -0500, Mike Christie wrote:
> > Patrick Mansfield wrote:
> > >On Tue, Jun 07, 2005 at 10:26:16AM -0500, Michael Christie wrote:
> > >
> > >>Quoting Patrick Mansfield <patmans at us.ibm.com>:
> > >
> > >
> > >>>Why can't the retries be passed down via a new blk req->retries?
> > >>>
> > >>
> > >>Is that all that is needed for dm-multipath? I thought this would be a 
> > >>good time
> > >>to add some code to allow the finer grained control of retries that could 
> > >>also
> > >>be used by dm and md. For example do you only want to retry certain 
> > >>failures X
> > >>numbeer of times?
> > >
> > >
> > >I was looking/thinking about the scsi_scan retries not multipath.
> > 
> > And I was hoping the same code/framework can be used for scsi, DM, MD, 
> > SG_IO and all other block layer drivers.
> 
> So use a req->retries instead of the fail fast flag?

Would be fine. Some drivers are messing with ->errors for that anyways,
so would be nice to clean that up.

It would need to be done _very_ carefully though!

-- 
Jens Axboe