From: Ming Lei <[email protected]>
To: Sagi Grimberg <[email protected]>
Cc: Gabriel Krisman Bertazi <[email protected]>,
Jens Axboe <[email protected]>,
[email protected],
Harris James R <[email protected]>,
[email protected], [email protected],
ZiyangZhang <[email protected]>,
Xiaoguang Wang <[email protected]>,
Stefan Hajnoczi <[email protected]>,
[email protected]
Subject: Re: [PATCH V3 1/1] ublk: add io_uring based userspace block driver
Date: Tue, 5 Jul 2022 08:43:43 +0800 [thread overview]
Message-ID: <YsOJP9BaD0LUpsgg@T590> (raw)
In-Reply-To: <[email protected]>
On Mon, Jul 04, 2022 at 07:19:09PM +0300, Sagi Grimberg wrote:
>
> > > > > > diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
> > > > > > index fdb81f2794cd..d218089cdbec 100644
> > > > > > --- a/drivers/block/Kconfig
> > > > > > +++ b/drivers/block/Kconfig
> > > > > > @@ -408,6 +408,12 @@ config BLK_DEV_RBD
> > > > > > If unsure, say N.
> > > > > > +config BLK_DEV_UBLK
> > > > > > + bool "Userspace block driver"
> > > > >
> > > > > Really? why compile this to the kernel and not tristate as loadable
> > > > > module?
> > > > So far, this is only one reason: task_work_add() is required, which
> > > > isn't exported for modules.
> > >
> > > So why not exporting it?
> > > Doesn't seem like a good justification to build it into the kernel.
> >
> > Sagi,
> >
> > If I understand correctly, the task_work_add function is quite a core
> > API that we probably want to avoid exposing directly to (out-of-tree)
> > modules? I agree, though, it would be great to have this buildable as a
> > module for general use cases. Would it make sense to have it exposed
> > through a thin built-in wrapper, specific to UBD, which is exported, and
> > therefore able to invoke that function? Is it a reasonable approach?
>
> All I'm saying is that either we should expose it (or an interface to
> it) if it has merit, or use something else (use a workqueue).
There isn't replacement for task_work_add().
If module has to be supported, we can add one command for running the
work function in the ubq context, that will add some cost.
> Having a block driver driver builtin is probably not the answer.
Not sure, there are at least two drivers which use the API.
Thanks,
Ming
next prev parent reply other threads:[~2022-07-05 0:44 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-28 16:08 [PATCH V3 0/1] ublk: add io_uring based userspace block driver Ming Lei
2022-06-28 16:08 ` [PATCH V3 1/1] " Ming Lei
2022-06-30 11:35 ` Ziyang Zhang
2022-06-30 12:33 ` Ming Lei
2022-07-01 2:47 ` Ziyang Zhang
2022-07-01 4:06 ` Ming Lei
2022-07-04 11:17 ` Sagi Grimberg
2022-07-04 12:34 ` Ming Lei
2022-07-04 14:00 ` Sagi Grimberg
2022-07-04 16:13 ` Gabriel Krisman Bertazi
2022-07-04 16:19 ` Sagi Grimberg
2022-07-05 0:43 ` Ming Lei [this message]
2022-07-04 22:10 ` Gabriel Krisman Bertazi
2022-07-05 4:16 ` Ziyang Zhang
2022-07-05 8:12 ` Ming Lei
2022-07-05 8:06 ` Ming Lei
2022-07-07 7:49 ` Ming Lei
2022-07-07 7:58 ` Ming Lei
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