dm: fix REQ_OP_ZONE_REPORT bio handling

A REQ_OP_ZONE_REPORT bio is not a medium access command.  Its number of
sectors indicates the maximum size allowed for the report reply size and
not an amount of sectors accessed from the device.  REQ_OP_ZONE_REPORT
bios should thus not be split depending on the target device maximum I/O
length but passed as-is.  Note that it is the responsability of the
target to remap and format the report reply.
Signed-off-by: NDamien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Reviewed-by: NBart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

drivers/md/dm.c

@@ -1152,7 +1152,8 @@ static int clone_bio(struct dm_target_io *tio, struct bio *bio,
 			return r;
 	}
 
-	bio_advance(clone, to_bytes(sector - clone->bi_iter.bi_sector));
+	if (bio_op(bio) != REQ_OP_ZONE_REPORT)
+		bio_advance(clone, to_bytes(sector - clone->bi_iter.bi_sector));
 	clone->bi_iter.bi_size = to_bytes(len);
 
 	if (unlikely(bio_integrity(bio) != NULL))
@@ -1341,7 +1342,11 @@ static int __split_and_process_non_flush(struct clone_info *ci)
 	if (!dm_target_is_valid(ti))
 		return -EIO;
 
-	len = min_t(sector_t, max_io_len(ci->sector, ti), ci->sector_count);
+	if (bio_op(bio) == REQ_OP_ZONE_REPORT)
+		len = ci->sector_count;
+	else
+		len = min_t(sector_t, max_io_len(ci->sector, ti),
+			    ci->sector_count);
 
 	r = __clone_and_map_data_bio(ci, ti, ci->sector, &len);
 	if (r < 0)