RE: [PATCH 1/2] block: add zone_desc_ext_bytes to sysfs

[Matias Bjorling <Matias.Bjorling@wdc.com>]

> -----Original Message-----
> From: Niklas Cassel <Niklas.Cassel@wdc.com>
> Sent: Monday, 29 June 2020 11.04
> To: Damien Le Moal <Damien.LeMoal@wdc.com>
> Cc: Matias Bjorling <Matias.Bjorling@wdc.com>; axboe@kernel.dk;
> kbusch@kernel.org; hch@lst.de; sagi@grimberg.me;
> martin.petersen@oracle.com; Hans Holmberg <Hans.Holmberg@wdc.com>;
> linux-scsi@vger.kernel.org; linux-kernel@vger.kernel.org; linux-
> block@vger.kernel.org; linux-nvme@lists.infradead.org
> Subject: Re: [PATCH 1/2] block: add zone_desc_ext_bytes to sysfs
> 
> On Mon, Jun 29, 2020 at 12:52:46AM +0000, Damien Le Moal wrote:
> > On 2020/06/29 8:01, Matias Bjorling wrote:
> > > The NVMe Zoned Namespace Command Set adds support for associating
> > > data to a zone through the Zone Descriptor Extension feature.
> > >
> > > The Zone Descriptor Extension size is fixed to a multiple of 64
> > > bytes. A value of zero communicates the feature is not available.
> > > A value larger than zero communites the feature is available, and
> > > the specified Zone Descriptor Extension size in bytes.
> > >
> > > The Zone Descriptor Extension feature is only available in the NVMe
> > > Zoned Namespaces Command Set. Devices that supports ZAC/ZBC
> > > therefore reports this value as zero, where as the NVMe device
> > > driver reports the Zone Descriptor Extension size from the specific
> > > device.
> > >
> > > Signed-off-by: Matias Bjørling <matias.bjorling@wdc.com>
> > > ---
> > >  Documentation/block/queue-sysfs.rst |  6 ++++++
> > >  block/blk-sysfs.c                   | 15 ++++++++++++++-
> > >  drivers/nvme/host/zns.c             |  1 +
> > >  drivers/scsi/sd_zbc.c               |  1 +
> > >  include/linux/blkdev.h              | 22 ++++++++++++++++++++++
> > >  5 files changed, 44 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/Documentation/block/queue-sysfs.rst
> > > b/Documentation/block/queue-sysfs.rst
> > > index f261a5c84170..c4fa195c87b4 100644
> 
> (snip)
> 
> > >  static struct queue_sysfs_entry queue_nomerges_entry = {
> > >  	.attr = {.name = "nomerges", .mode = 0644 },
> > >  	.show = queue_nomerges_show,
> > > @@ -787,6 +798,7 @@ static struct attribute *queue_attrs[] = {
> > >  	&queue_nr_zones_entry.attr,
> > >  	&queue_max_open_zones_entry.attr,
> > >  	&queue_max_active_zones_entry.attr,
> >
> > Which tree is this patch based on ? Not I have seen any patch
> > introducing max active zones.
> 
> The cover letter forgot to mention this patch series' dependencies.
> I assume that it is based on the following patch series:
> https://lore.kernel.org/linux-block/20200622162530.1287650-1-
> kbusch@kernel.org/
> https://lore.kernel.org/linux-block/20200616102546.491961-1-
> niklas.cassel@wdc.com/
> 

Very true. Thanks, Niklas.

I'll rebase this work when the above patchsets have been picked up.

> 
> Kind regards,
> Niklas