Commit 0dbcfe24 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

block: look up holders by bdev 



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

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210804094147.459763-4-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent fbd9a395

block/genhd.c

+3 −1
Original line number Diff line number Diff line
@@ -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:

block/holder.c

+9 −9
Original line number Diff line number Diff line
@@ -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);

fs/block_dev.c

+0 −3
Original line number Diff line number Diff line
@@ -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);

include/linux/blk_types.h

+0 −3
Original line number Diff line number Diff line
@@ -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 */

include/linux/genhd.h

+3 −1
Original line number Diff line number Diff line
@@ -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;