dm: introduce dm_remap_zone_report()

A target driver support zoned block devices and exposing it as such may
receive REQ_OP_ZONE_REPORT request for the user to determine the mapped
device zone configuration. To process properly such request, the target
driver may need to remap the zone descriptors provided in the report
reply. The helper function dm_remap_zone_report() does this generically
using only the target start offset and length and the start offset
within the target device.

dm_remap_zone_report() will remap the start sector of all zones
reported. If the report includes sequential zones, the write pointer
position of these zones will also be remapped.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 186ef74009cb..0c1b50ad23b0 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -450,6 +450,8 @@ struct gendisk *dm_disk(struct mapped_device *md);
 int dm_suspended(struct dm_target *ti);
 int dm_noflush_suspending(struct dm_target *ti);
 void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors);
+void dm_remap_zone_report(struct dm_target *ti, struct bio *bio,
+			  sector_t start);
 union map_info *dm_get_rq_mapinfo(struct request *rq);
 
 struct queue_limits *dm_get_queue_limits(struct mapped_device *md);