dm: delay registering the gendisk

device mapper is currently the only outlier that tries to call
register_disk after add_disk, leading to fairly inconsistent state
of these block layer data structures.  Instead change device-mapper
to just register the gendisk later now that the holder mechanism
can cope with that.

Note that this introduces a user visible change: the dm kobject is
now only visible after the initial table has been loaded.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20210804094147.459763-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2021-08-04 11:41:46 +02:00 committed by Jens Axboe
parent ba30585936
commit 89f871af1b
2 changed files with 12 additions and 14 deletions

View File

@ -559,7 +559,6 @@ int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t)
err = blk_mq_init_allocated_queue(md->tag_set, md->queue);
if (err)
goto out_tag_set;
elevator_init_mq(md->queue);
return 0;
out_tag_set:

View File

@ -1693,7 +1693,10 @@ static void cleanup_mapped_device(struct mapped_device *md)
spin_lock(&_minor_lock);
md->disk->private_data = NULL;
spin_unlock(&_minor_lock);
del_gendisk(md->disk);
if (dm_get_md_type(md) != DM_TYPE_NONE) {
dm_sysfs_exit(md);
del_gendisk(md->disk);
}
dm_queue_destroy_keyslot_manager(md->queue);
blk_cleanup_disk(md->disk);
}
@ -1788,7 +1791,6 @@ static struct mapped_device *alloc_dev(int minor)
goto bad;
}
add_disk_no_queue_reg(md->disk);
format_dev_t(md->name, MKDEV(_major, minor));
md->wq = alloc_workqueue("kdmflush", WQ_MEM_RECLAIM, 0);
@ -1989,19 +1991,12 @@ static struct dm_table *__unbind(struct mapped_device *md)
*/
int dm_create(int minor, struct mapped_device **result)
{
int r;
struct mapped_device *md;
md = alloc_dev(minor);
if (!md)
return -ENXIO;
r = dm_sysfs_init(md);
if (r) {
free_dev(md);
return r;
}
*result = md;
return 0;
}
@ -2081,10 +2076,15 @@ int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t)
r = dm_table_set_restrictions(t, md->queue, &limits);
if (r)
return r;
add_disk(md->disk);
r = dm_sysfs_init(md);
if (r) {
del_gendisk(md->disk);
return r;
}
md->type = type;
blk_register_queue(md->disk);
return 0;
}
@ -2190,7 +2190,6 @@ static void __dm_destroy(struct mapped_device *md, bool wait)
DMWARN("%s: Forcibly removing mapped_device still in use! (%d users)",
dm_device_name(md), atomic_read(&md->holders));
dm_sysfs_exit(md);
dm_table_destroy(__unbind(md));
free_dev(md);
}