On Thu, May 07, 2020 at 07:16:26AM -0700, Christoph Hellwig wrote: > On Thu, May 07, 2020 at 04:52:36PM +0800, Ming Lei wrote: > > for (i = 1; i < ptbl->len; i++) { > > part = rcu_dereference(ptbl->part[i]); > > > > if (part && sector_in_part(part, sector)) { > > + if (!hd_struct_try_get(part)) > > + goto exit; > > I think this needs the comment that was in blk_account_io_start to > explain the logic. Also no need for the goto, this can just be a break. OK, not did it because I thought the logic is straightforward. > > > - rcu_assign_pointer(ptbl->last_lookup, NULL); > > kobject_put(part->holder_dir); > > device_del(part_to_dev(part)); > > > > @@ -393,6 +402,7 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno, > > p->nr_sects = len; > > p->partno = partno; > > p->policy = get_disk_ro(disk); > > + p->disk = disk; > > Do we really need this pointer? Can't we use part_to_disk in the > free path for some reason? Looks I did miss this function, :-) Thanks, Ming