[dm-devel] split scsi passthrough fields out of struct request V2

[Bart Van Assche]

On Thu, 2017-01-26 at 17:41 -0700, Jens Axboe wrote:
> On 01/26/2017 05:38 PM, Bart Van Assche wrote:
> > I see similar behavior with the blk-mq-sched branch of
> > git://git.kernel.dk/linux-block.git (git commit ID 0efe27068ecf):
> > booting happens much slower than usual and I/O hangs if I run the
> > srp-test software.
> 
> Please don't run that, run for-4.11/block and merge it to master.
> Same behavior?

I have not yet had the chance to run the srp-test software against that
kernel. But I already see that booting takes more than ten times longer
than usual. Note: as far as I know the dm-mpath driver is not involved
in the boot process of my test system.

> > Regarding creating a similar dm setup: I hope that in the future it
> > will become possible to run the srp-test software without any special
> > hardware and with in-tree drivers. Today running the srp-test software
> > with in-tree drivers namely requires IB hardware. This is how to run the
> > srp-test software today with in-tree drivers:
> > * Find a system with at least two InfiniBand ports.
> > * Make sure that the appropriate IB driver in the kernel is enabled and
> >   also that LIO (CONFIG_TARGET_CORE=m and CONFIG_TCM_FILEIO=m), ib_srp,
> >   ib_srpt and dm-mpath are built as kernel modules.
> > * If none of the IB ports are connected to an IB switch, connect the
> >   two ports to each other and configure and start the opensm software
> >   such that the port states change from "Initializing" to "Active".
> > * Check with "ibstat | grep State: Active" that at least one port is
> >   in the active state.
> > * Configure multipathd as explained in
> >   https://github.com/bvanassche/srp-test/blob/master/README.md.
> > * Restart multipathd to make sure it picks up /etc/multipath.conf.
> > * Clone https://github.com/bvanassche/srp-test and start it as follows:
> >   srp-test/run_tests -t 02-mq
> 
> I can't run that. Any chance of a test case that doesn't require IB?

It is possible to run that test on top of the SoftRoCE driver. I will first
check myself whether the latest version of the SoftRoCE driver is stable
enough to run srp-test on top of it (see also
https://github.com/dledford/linux/commits/k.o/for-4.11).

Bart.