[dm-devel] [PATCH v4 10/11] block: add a report_zones method

[Mike Snitzer]

On Fri, Oct 12 2018 at  6:08am -0400,
Damien Le Moal <damien.lemoal at wdc.com> wrote:

> From: Christoph Hellwig <hch at lst.de>
> 
> Dispatching a report zones command through the request queue is a major
> pain due to the command reply payload rewriting necessary. Given that
> blkdev_report_zones() is executing everything synchronously, implement
> report zones as a block device file operation instead, allowing major
> simplification of the code in many places.
> 
> sd, null-blk, dm-linear and dm-flakey being the only block device
> drivers supporting exposing zoned block devices, these drivers are
> modified to provide the device side implementation of the
> report_zones() block device file operation.
> 
> For device mappers, a new report_zones() target type operation is
> defined so that the upper block layer calls blkdev_report_zones() can
> be propagated down to the underlying devices of the dm targets.
> Implementation for this new operation is added to the dm-linear and
> dm-flakey targets.
> 
> Signed-off-by: Christoph Hellwig <hch at lst.de>
> [Damien]
> * Changed method block_device argument to gendisk
> * Various bug fixes and improvements
> * Added support for null_blk, dm-linear and dm-flakey.
> Signed-off-by: Damien Le Moal <damien.lemoal at wdc.com>
> Reviewed-by: Hannes Reinecke <hare at suse.com>

Reviewed-by: Mike Snitzer <snitzer at redhat.com>