Merge tag 'for-4.19/dm-fixes-3' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Mike writes:
  "device mapper fixes for 4.19 final

   - Fix a DM cache module init error path bug that doesn't properly
     cleanup a KMEM_CACHE if target registration fails.

   - Two stable@ fixes for DM zoned target; 4.20 will have changes that
     eliminate this code entirely but <= 4.19 needs these changes."

* tag 'for-4.19/dm-fixes-3' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm linear: eliminate linear_end_io call if CONFIG_DM_ZONED disabled
  dm: fix report zone remapping to account for partition offset
  dm cache: destroy migration_cache if cache target registration failed

drivers/md/dm-cache-target.c

@@ -3484,14 +3484,13 @@ static int __init dm_cache_init(void)
 	int r;
 
 	migration_cache = KMEM_CACHE(dm_cache_migration, 0);
-	if (!migration_cache) {
-		dm_unregister_target(&cache_target);
+	if (!migration_cache)
 		return -ENOMEM;
-	}
 
 	r = dm_register_target(&cache_target);
 	if (r) {
 		DMERR("cache target registration failed: %d", r);
+		kmem_cache_destroy(migration_cache);
 		return r;
 	}
 

drivers/md/dm-linear.c

@@ -102,6 +102,7 @@ static int linear_map(struct dm_target *ti, struct bio *bio)
 	return DM_MAPIO_REMAPPED;
 }
 
+#ifdef CONFIG_DM_ZONED
 static int linear_end_io(struct dm_target *ti, struct bio *bio,
 			 blk_status_t *error)
 {
@@ -112,6 +113,7 @@ static int linear_end_io(struct dm_target *ti, struct bio *bio,
 
 	return DM_ENDIO_DONE;
 }
+#endif
 
 static void linear_status(struct dm_target *ti, status_type_t type,
 			  unsigned status_flags, char *result, unsigned maxlen)
@@ -208,12 +210,16 @@ static size_t linear_dax_copy_to_iter(struct dm_target *ti, pgoff_t pgoff,
 static struct target_type linear_target = {
 	.name   = "linear",
 	.version = {1, 4, 0},
+#ifdef CONFIG_DM_ZONED
+	.end_io = linear_end_io,
 	.features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_ZONED_HM,
+#else
+	.features = DM_TARGET_PASSES_INTEGRITY,
+#endif
 	.module = THIS_MODULE,
 	.ctr    = linear_ctr,
 	.dtr    = linear_dtr,
 	.map    = linear_map,
-	.end_io = linear_end_io,
 	.status = linear_status,
 	.prepare_ioctl = linear_prepare_ioctl,
 	.iterate_devices = linear_iterate_devices,

drivers/md/dm.c

@@ -1155,12 +1155,14 @@ 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.
+ * The zone descriptors obtained with a zone report indicate zone positions
+ * within the target backing device, regardless of that device is a partition
+ * and regardless of the target mapping start sector on the device or partition.
+ * The zone descriptors start sector and write pointer position must be adjusted
+ * to match their relative 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
+ * backing device.
  */
 void dm_remap_zone_report(struct dm_target *ti, struct bio *bio, sector_t start)
 {
@@ -1171,6 +1173,7 @@ void dm_remap_zone_report(struct dm_target *ti, struct bio *bio, sector_t start)
 	struct blk_zone *zone;
 	unsigned int nr_rep = 0;
 	unsigned int ofst;
+	sector_t part_offset;
 	struct bio_vec bvec;
 	struct bvec_iter iter;
 	void *addr;
@@ -1178,6 +1181,15 @@ void dm_remap_zone_report(struct dm_target *ti, struct bio *bio, sector_t start)
 	if (bio->bi_status)
 		return;
 
+	/*
+	 * bio sector was incremented by the request size on completion. Taking
+	 * into account the original request sector, the target start offset on
+	 * the backing device and the target mapping offset (ti->begin), the
+	 * start sector of the backing device. The partition offset is always 0
+	 * if the target uses a whole device.
+	 */
+	part_offset = bio->bi_iter.bi_sector + ti->begin - (start + bio_end_sector(report_bio));
+
 	/*
 	 * Remap the start sector of the reported zones. For sequential zones,
 	 * also remap the write pointer position.
@@ -1195,6 +1207,7 @@ void dm_remap_zone_report(struct dm_target *ti, struct bio *bio, sector_t start)
 		/* Set zones start sector */
 		while (hdr->nr_zones && ofst < bvec.bv_len) {
 			zone = addr + ofst;
+			zone->start -= part_offset;
 			if (zone->start >= start + ti->len) {
 				hdr->nr_zones = 0;
 				break;
@@ -1206,7 +1219,7 @@ void dm_remap_zone_report(struct dm_target *ti, struct bio *bio, sector_t start)
 				else if (zone->cond == BLK_ZONE_COND_EMPTY)
 					zone->wp = zone->start;
 				else
-					zone->wp = zone->wp + ti->begin - start;
+					zone->wp = zone->wp + ti->begin - start - part_offset;
 			}
 			ofst += sizeof(struct blk_zone);
 			hdr->nr_zones--;