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From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>, Mike Snitzer <snitzer@redhat.com>
Cc: linux-block@vger.kernel.org, dm-devel@redhat.com
Subject: [dm-devel] [PATCH 7/8] dm: delay registering the gendisk
Date: Sun, 25 Jul 2021 07:54:57 +0200	[thread overview]
Message-ID: <20210725055458.29008-8-hch@lst.de> (raw)
In-Reply-To: <20210725055458.29008-1-hch@lst.de>

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>
---
 drivers/md/dm-rq.c |  1 -
 drivers/md/dm.c    | 23 +++++++++++------------
 2 files changed, 11 insertions(+), 13 deletions(-)

diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c
index 0dbd48cbdff9..5b95eea517d1 100644
--- a/drivers/md/dm-rq.c
+++ b/drivers/md/dm-rq.c
@@ -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:
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index f003bd5b93ce..7981b7287628 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -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;
-	md->type = type;
 
-	blk_register_queue(md->disk);
+	add_disk(md->disk);
 
+	r = dm_sysfs_init(md);
+	if (r) {
+		del_gendisk(md->disk);
+		return r;
+	}
+	md->type = type;
 	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);
 }
-- 
2.30.2

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  parent reply	other threads:[~2021-07-25  6:00 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-25  5:54 [dm-devel] use regular gendisk registration in device mapper Christoph Hellwig
2021-07-25  5:54 ` [dm-devel] [PATCH 1/8] block: make the block holder code optional Christoph Hellwig
2021-07-29 16:25   ` Mike Snitzer
2021-07-25  5:54 ` [dm-devel] [PATCH 2/8] block: remove the extra kobject reference in bd_link_disk_holder Christoph Hellwig
2021-07-29 16:27   ` Mike Snitzer
2021-07-25  5:54 ` [dm-devel] [PATCH 3/8] block: look up holders by bdev Christoph Hellwig
2021-07-25  5:54 ` [dm-devel] [PATCH 4/8] block: support delayed holder registration Christoph Hellwig
2021-07-27 16:06   ` Mike Snitzer
2021-07-28  6:54     ` Christoph Hellwig
2021-07-29 16:32   ` Mike Snitzer
2021-07-25  5:54 ` [dm-devel] [PATCH 5/8] dm: cleanup cleanup_mapped_device Christoph Hellwig
2021-07-29 16:33   ` Mike Snitzer
2021-07-25  5:54 ` [dm-devel] [PATCH 6/8] dm: move setting md->type into dm_setup_md_queue Christoph Hellwig
2021-07-29 16:34   ` Mike Snitzer
2021-07-25  5:54 ` Christoph Hellwig [this message]
2021-07-29 16:36   ` [dm-devel] [PATCH 7/8] dm: delay registering the gendisk Mike Snitzer
2021-07-25  5:54 ` [dm-devel] [PATCH 8/8] block: remove support for delayed queue registrations Christoph Hellwig
2021-07-29 16:37   ` Mike Snitzer
2021-07-27 15:58 ` [dm-devel] use regular gendisk registration in device mapper Mike Snitzer
2021-07-27 16:02   ` Christoph Hellwig
2021-07-27 16:18     ` Mike Snitzer
2021-07-27 20:38       ` Milan Broz
2021-07-28  7:06         ` Christoph Hellwig
2021-07-28  8:37           ` Milan Broz
2021-07-28 11:24             ` Christoph Hellwig
2021-07-29 15:01               ` Milan Broz
2021-07-28 16:17         ` Mike Snitzer
2021-07-29  7:50           ` Milan Broz
2021-07-27 22:52       ` Mike Snitzer
2021-08-04  9:41 [dm-devel] use regular gendisk registration in device mapper v2 Christoph Hellwig
2021-08-04  9:41 ` [dm-devel] [PATCH 7/8] dm: delay registering the gendisk Christoph Hellwig
2021-08-09 23:31   ` Alasdair G Kergon
2021-08-10  0:17     ` Alasdair G Kergon
2021-08-10 13:12     ` Peter Rajnoha
2021-08-10 15:05       ` Alasdair G Kergon
2022-07-07  3:29   ` Yu Kuai
2022-07-07  5:24     ` Christoph Hellwig
2022-07-07  7:20       ` Yu Kuai
2022-07-15  3:24         ` Yu Kuai
2022-08-01  1:04           ` Yu Kuai

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