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

[Michael Christie]

Quoting Patrick Mansfield <patmans at us.ibm.com>:

> On Sun, Jun 05, 2005 at 12:15:27AM -0700, Mike Christie wrote:
> > On Sat, 2005-06-04 at 09:07, James Bottomley wrote:
> 
> > > Here's the proof of concept for this one.  It converts scsi_wait_req to
> > > do correct REQ_BLOCK_PC submission (and works nicely in my setup).
> 
> That is nice ... I didn't realize Mike's change allowed that.
> 
> > > There's some loss of functionality to this: retries are no longer
> > > controllable (except by setting REQ_FASTFAIL) and the wait_req API needs
> > > to be altered, but it looks very nice.
> 
> Mike your patch did not replace the retries.
> 
> 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?