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authorDamien Le Moal2017-05-08 16:40:48 -0700
committerMike Snitzer2017-06-19 11:03:51 -0400
commit10999307c14eac281fbec3ada73bee7a05bd41dc (patch)
treef8898affec3c6857bfe1dcf86fd44160443d9fea
parent264c869d44dcff17e3b108dbb2fbea24bed08538 (diff)
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>
-rw-r--r--drivers/md/dm.c79
-rw-r--r--include/linux/device-mapper.h2
2 files changed, 81 insertions, 0 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index e38d1d7d17d6..96bd13e581cd 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1013,6 +1013,85 @@ void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors)
EXPORT_SYMBOL_GPL(dm_accept_partial_bio);
/*
+ * The zone descriptors obtained with a zone report indicate
+ * zone positions within the target device. The zone descriptors
+ * must be remapped to match their position within the dm device.
+ * A target may call dm_remap_zone_report after completion of a
+ * REQ_OP_ZONE_REPORT bio to remap the zone descriptors obtained
+ * from the target device mapping to the dm device.
+ */
+void dm_remap_zone_report(struct dm_target *ti, struct bio *bio, sector_t start)
+{
+#ifdef CONFIG_BLK_DEV_ZONED
+ struct dm_target_io *tio = container_of(bio, struct dm_target_io, clone);
+ struct bio *report_bio = tio->io->bio;
+ struct blk_zone_report_hdr *hdr = NULL;
+ struct blk_zone *zone;
+ unsigned int nr_rep = 0;
+ unsigned int ofst;
+ struct bio_vec bvec;
+ struct bvec_iter iter;
+ void *addr;
+
+ if (bio->bi_status)
+ return;
+
+ /*
+ * Remap the start sector of the reported zones. For sequential zones,
+ * also remap the write pointer position.
+ */
+ bio_for_each_segment(bvec, report_bio, iter) {
+ addr = kmap_atomic(bvec.bv_page);
+
+ /* Remember the report header in the first page */
+ if (!hdr) {
+ hdr = addr;
+ ofst = sizeof(struct blk_zone_report_hdr);
+ } else
+ ofst = 0;
+
+ /* Set zones start sector */
+ while (hdr->nr_zones && ofst < bvec.bv_len) {
+ zone = addr + ofst;
+ if (zone->start >= start + ti->len) {
+ hdr->nr_zones = 0;
+ break;
+ }
+ zone->start = zone->start + ti->begin - start;
+ if (zone->type != BLK_ZONE_TYPE_CONVENTIONAL) {
+ if (zone->cond == BLK_ZONE_COND_FULL)
+ zone->wp = zone->start + zone->len;
+ else if (zone->cond == BLK_ZONE_COND_EMPTY)
+ zone->wp = zone->start;
+ else
+ zone->wp = zone->wp + ti->begin - start;
+ }
+ ofst += sizeof(struct blk_zone);
+ hdr->nr_zones--;
+ nr_rep++;
+ }
+
+ if (addr != hdr)
+ kunmap_atomic(addr);
+
+ if (!hdr->nr_zones)
+ break;
+ }
+
+ if (hdr) {
+ hdr->nr_zones = nr_rep;
+ kunmap_atomic(hdr);
+ }
+
+ bio_advance(report_bio, report_bio->bi_iter.bi_size);
+
+#else /* !CONFIG_BLK_DEV_ZONED */
+ bio->bi_status = BLK_STS_NOTSUPP;
+#endif
+}
+EXPORT_SYMBOL_GPL(dm_remap_zone_report);
+
+/*
* Flush current->bio_list when the target map method blocks.
* This fixes deadlocks in snapshot and possibly in other targets.
*/
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);