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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 3/8] block: look up holders by bdev
Date: Wed,  4 Aug 2021 11:41:42 +0200	[thread overview]
Message-ID: <20210804094147.459763-4-hch@lst.de> (raw)
In-Reply-To: <20210804094147.459763-1-hch@lst.de>

Invert they way the holder relations are tracked.  This very
slightly reduces the memory overhead for partitioned devices.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c             |  4 +++-
 block/holder.c            | 18 +++++++++---------
 fs/block_dev.c            |  3 ---
 include/linux/blk_types.h |  3 ---
 include/linux/genhd.h     |  4 +++-
 5 files changed, 15 insertions(+), 17 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index a4817e42f3a3..cd4eab744667 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1289,7 +1289,9 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
 	disk_to_dev(disk)->type = &disk_type;
 	device_initialize(disk_to_dev(disk));
 	inc_diskseq(disk);
-
+#ifdef CONFIG_BLOCK_HOLDER_DEPRECATED
+	INIT_LIST_HEAD(&disk->slave_bdevs);
+#endif
 	return disk;
 
 out_destroy_part_tbl:
diff --git a/block/holder.c b/block/holder.c
index 960654a71342..11e65d99a9fb 100644
--- a/block/holder.c
+++ b/block/holder.c
@@ -3,7 +3,7 @@
 
 struct bd_holder_disk {
 	struct list_head	list;
-	struct gendisk		*disk;
+	struct block_device	*bdev;
 	int			refcnt;
 };
 
@@ -12,8 +12,8 @@ static struct bd_holder_disk *bd_find_holder_disk(struct block_device *bdev,
 {
 	struct bd_holder_disk *holder;
 
-	list_for_each_entry(holder, &bdev->bd_holder_disks, list)
-		if (holder->disk == disk)
+	list_for_each_entry(holder, &disk->slave_bdevs, list)
+		if (holder->bdev == bdev)
 			return holder;
 	return NULL;
 }
@@ -61,7 +61,7 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
 	struct bd_holder_disk *holder;
 	int ret = 0;
 
-	mutex_lock(&bdev->bd_disk->open_mutex);
+	mutex_lock(&disk->open_mutex);
 
 	WARN_ON_ONCE(!bdev->bd_holder);
 
@@ -82,7 +82,7 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
 	}
 
 	INIT_LIST_HEAD(&holder->list);
-	holder->disk = disk;
+	holder->bdev = bdev;
 	holder->refcnt = 1;
 
 	ret = add_symlink(disk->slave_dir, bdev_kobj(bdev));
@@ -93,7 +93,7 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
 	if (ret)
 		goto out_del;
 
-	list_add(&holder->list, &bdev->bd_holder_disks);
+	list_add(&holder->list, &disk->slave_bdevs);
 	goto out_unlock;
 
 out_del:
@@ -101,7 +101,7 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
 out_free:
 	kfree(holder);
 out_unlock:
-	mutex_unlock(&bdev->bd_disk->open_mutex);
+	mutex_unlock(&disk->open_mutex);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(bd_link_disk_holder);
@@ -120,7 +120,7 @@ void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
 {
 	struct bd_holder_disk *holder;
 
-	mutex_lock(&bdev->bd_disk->open_mutex);
+	mutex_lock(&disk->open_mutex);
 	holder = bd_find_holder_disk(bdev, disk);
 	if (!WARN_ON_ONCE(holder == NULL) && !--holder->refcnt) {
 		del_symlink(disk->slave_dir, bdev_kobj(bdev));
@@ -128,6 +128,6 @@ void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
 		list_del_init(&holder->list);
 		kfree(holder);
 	}
-	mutex_unlock(&bdev->bd_disk->open_mutex);
+	mutex_unlock(&disk->open_mutex);
 }
 EXPORT_SYMBOL_GPL(bd_unlink_disk_holder);
diff --git a/fs/block_dev.c b/fs/block_dev.c
index ae9651cad923..cc801767a377 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -902,9 +902,6 @@ struct block_device *bdev_alloc(struct gendisk *disk, u8 partno)
 	bdev->bd_disk = disk;
 	bdev->bd_partno = partno;
 	bdev->bd_inode = inode;
-#ifdef CONFIG_BLOCK_HOLDER_DEPRECATED
-	INIT_LIST_HEAD(&bdev->bd_holder_disks);
-#endif
 	bdev->bd_stats = alloc_percpu(struct disk_stats);
 	if (!bdev->bd_stats) {
 		iput(inode);
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 7a4e139d24ef..e92735655684 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -34,9 +34,6 @@ struct block_device {
 	void *			bd_holder;
 	int			bd_holders;
 	bool			bd_write_holder;
-#ifdef CONFIG_BLOCK_HOLDER_DEPRECATED
-	struct list_head	bd_holder_disks;
-#endif
 	struct kobject		*bd_holder_dir;
 	u8			bd_partno;
 	spinlock_t		bd_size_lock; /* for bd_inode->i_size updates */
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index e21a91c16a79..0721807d76ee 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -159,7 +159,9 @@ struct gendisk {
 	unsigned open_partitions;	/* number of open partitions */
 
 	struct kobject *slave_dir;
-
+#ifdef CONFIG_BLOCK_HOLDER_DEPRECATED
+	struct list_head slave_bdevs;
+#endif
 	struct timer_rand_state *random;
 	atomic_t sync_io;		/* RAID */
 	struct disk_events *ev;
-- 
2.30.2

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  parent reply	other threads:[~2021-08-04  9:44 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
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 1/8] block: make the block holder code optional Christoph Hellwig
2021-08-04  9:41 ` [dm-devel] [PATCH 2/8] block: remove the extra kobject reference in bd_link_disk_holder Christoph Hellwig
2021-08-04  9:41 ` Christoph Hellwig [this message]
2021-08-04  9:41 ` [dm-devel] [PATCH 4/8] block: support delayed holder registration Christoph Hellwig
     [not found]   ` <CGME20210810213058eucas1p109323e3c3ecaa76d37d8cf63b6d8ecfd@eucas1p1.samsung.com>
2021-08-10 21:30     ` Marek Szyprowski
2021-08-14 21:13   ` Guenter Roeck
2021-08-15  7:07     ` Christoph Hellwig
2021-08-15 14:27       ` Guenter Roeck
2021-08-16  7:21         ` Christoph Hellwig
2021-08-16 14:17           ` Guenter Roeck
2021-08-20 15:08             ` Christoph Hellwig
2021-08-21  3:17               ` Guenter Roeck
2021-08-18  2:51           ` Guenter Roeck
2021-08-04  9:41 ` [dm-devel] [PATCH 5/8] dm: cleanup cleanup_mapped_device Christoph Hellwig
2021-08-04  9:41 ` [dm-devel] [PATCH 6/8] dm: move setting md->type into dm_setup_md_queue 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
2021-08-04  9:41 ` [dm-devel] [PATCH 8/8] block: remove support for delayed queue registrations Christoph Hellwig
2021-08-09 17:51 ` [dm-devel] use regular gendisk registration in device mapper v2 Jens Axboe
2021-08-10  0:36 ` Alasdair G Kergon
2021-08-10 14:41   ` Alasdair G Kergon
2021-08-19 15:58 ` [dm-devel] holders not working properly, regression [was: Re: use regular gendisk registration in device mapper v2] Mike Snitzer
2021-08-19 18:05   ` Christoph Hellwig
2021-08-19 22:08     ` Mike Snitzer
  -- strict thread matches above, loose matches on Subject: below --
2021-07-25  5:54 [dm-devel] use regular gendisk registration in device mapper Christoph Hellwig
2021-07-25  5:54 ` [dm-devel] [PATCH 3/8] block: look up holders by bdev Christoph Hellwig

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