Re: [PATCH 4/6] mtip32xx: convert internal command issue to block IO path

[Bart Van Assche <Bart.VanAssche@sandisk.com>]

On Tue, 2017-05-02 at 09:25 -0600, Jens Axboe wrote:
> On 05/02/2017 09:16 AM, Christoph Hellwig wrote:
> > Any reason for the move from ->end_io_data to ->special?  I thought
> > that ->special was something we'd get rid of sooner or later now
> > that we can have additional per-cmd data even for !mq.
>=20
> With the switch to blk_execute_rq(), we can't be using end_io_data
> and end_io, as we use that internally for the wakeup. So I have to
> stuff it somewhere.
>=20
> The obvious option would be to move it to mtip_cmd, but we can't
> safely access that prior to having a driver tag assigned, which doesn't
> happen until we end up in our ->queue_rq(). So we need to stuff it
> somewhere.

Hello Jens,

Do you think it would be a good idea to allow blk_get_request() callers
to specify that a driver tag has to be allocated even if a scheduler has
been configured? That would make it possible to store completion data in
mtip_cmd for the mtip driver.

Thanks,

Bart.=