Re: [PATCH v3] null_blk: add support for max open/active zone limit for zoned devices

[Matias Bjørling]

On 23/09/2020 09.46, Johannes Thumshirn wrote:
> On 17/09/2020 09:57, Niklas Cassel wrote:
> > On Mon, Sep 07, 2020 at 08:18:26AM +0000, Niklas Cassel wrote:
> > > On Fri, Aug 28, 2020 at 12:54:00PM +0200, Niklas Cassel wrote:
> > > > Add support for user space to set a max open zone and a max active zone
> > > > limit via configfs. By default, the default values are 0 == no limit.
> > > >
> > > > Call the block layer API functions used for exposing the configured
> > > > limits to sysfs.
> > > >
> > > > Add accounting in null_blk_zoned so that these new limits are respected.
> > > > Performing an operation that would exceed these limits results in a
> > > > standard I/O error.
> > > >
> > > > A max open zone limit exists in the ZBC standard.
> > > > While null_blk_zoned is used to test the Zoned Block Device model in
> > > > Linux, when it comes to differences between ZBC and ZNS, null_blk_zoned
> > > > mostly follows ZBC.
> > > >
> > > > Therefore, implement the manage open zone resources function from ZBC,
> > > > but additionally add support for max active zones.
> > > > This enables user space not only to test against a device with an open
> > > > zone limit, but also to test against a device with an active zone limit.
> > > >
> > > > Signed-off-by: Niklas Cassel <niklas.cassel@xxxxxxx>
> > > > Reviewed-by: Damien Le Moal <damien.lemoal@xxxxxxx>
> > > > ---
> > > > Changes since v2:
> > > > -Picked up Damien's Reviewed-by tag.
> > > > -Fixed a typo in the commit message.
> > > > -Renamed null_manage_zone_resources() to null_has_zone_resources().
> > > >
> > > >   drivers/block/null_blk.h       |   5 +
> > > >   drivers/block/null_blk_main.c  |  16 +-
> > > >   drivers/block/null_blk_zoned.c | 319 +++++++++++++++++++++++++++------
> > > >   3 files changed, 282 insertions(+), 58 deletions(-)
> > > Hello Jens,
> > >
> > > A gentle ping on this.
> > >
> > > As far as I can tell, there are no outstanding review comments.
> >
> > Hello Jens,
> >
> > Pinging you from another address, in case my corporate email is getting
> > stuck in your spam filter.
> >
> > Kind regards,
> > Niklas
>
> Jens,
>
> Any chance we can get this queued up for 5.10? This is really helpful for e.g.
> the zonefs test suite or xfstests when btrfs HMZONED support lands.
>
> Thanks,
> 	Johannes

Thanks, Niklas.

Reviewed-by: Matias Bjørling <matias.bjorling@xxxxxxx>