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

[Tony Battersby]

> James Bottomley wrote:
> > Well ... while I've got your attention, the only complexity I see to
> > converting sg is the hd->iovec_count != 0 case, which is doing
vectored
> > SG from user land.
> >
> > This can be implemented (basically you do multiple bio attachment to
a
> > request), and probably in the block layer (since block SG_IO would
then
> > pick up the capability).
> >
> > How important is this functionality?  Are there any applications
using
> > it?
>
> I don't think it is important and I'm not aware of any
> real world applications that are using it. Naturally,
> I will find out if that is actually true after it
> gets removed.

My company (Cybernetics) sells several products that run embedded Linux
which use the userspace scatter-gather capability of the SG driver.
They are still running the 2.4 kernel series, but we will probably
switch to 2.6 at some point.

Anthony J. Battersby
Cybernetics