Re: [PATCH V5 0/2] ublk: add io_uring based userspace block driver

From: Ming Lei
Date: Wed Jul 13 2022 - 20:19:33 EST

On Wed, Jul 13, 2022 at 02:25:25PM -0600, Jens Axboe wrote:
> On 7/13/22 8:07 AM, Ming Lei wrote:
> > Hello Guys,
> >
> > ublk driver is one kernel driver for implementing generic userspace block
> > device/driver, which delivers io request from ublk block device(/dev/ublkbN) into
> > ublk server[1] which is the userspace part of ublk for communicating
> > with ublk driver and handling specific io logic by its target module.
> Ming, is this ready to get merged in an experimental state?

Hi Jens,

Yeah, I think so.

IO path can survive in xfstests(-g auto), and control path works
well in ublksrv builtin hotplug & 'kill -9' daemon test.

The UAPI data size should be good, but definition may change per
future requirement change, so I think it is ready to go as

If you are fine, please add the following delta change into patch 1,
or let me know if resend is needed.

diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index 2ba77fd960c2..e19fcab016ba 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -409,10 +409,13 @@ config BLK_DEV_RBD
If unsure, say N.

- tristate "Userspace block driver"
+ tristate "Userspace block driver (Experimental)"
select IO_URING
- io uring based userspace block driver.
+ io_uring based userspace block driver. Together with ublk server, ublk
+ has been working well, but interface with userspace or command data
+ definition isn't finalized yet, and might change according to future
+ requirement, so mark is as experimental now.

source "drivers/block/rnbd/Kconfig"