Commit d2c7f56f authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

loop: implement ->free_disk 



Ensure that the lo_device which is stored in the gendisk private
data is valid until the gendisk is freed.  Currently the loop driver
uses a lot of effort to make sure a device is not freed when it is
still in use, but to to fix a potential deadlock this will be relaxed
a bit soon.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220330052917.2566582-12-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 1fe0b1ac

drivers/block/loop.c

+12 −4
Original line number Diff line number Diff line
@@ -1761,6 +1761,14 @@ static void lo_release(struct gendisk *disk, fmode_t mode) 
	mutex_unlock(&lo->lo_mutex);

}



static void lo_free_disk(struct gendisk *disk)

{

	struct loop_device *lo = disk->private_data;



	mutex_destroy(&lo->lo_mutex);

	kfree(lo);

}



static const struct block_device_operations lo_fops = {

	.owner =	THIS_MODULE,

	.open =		lo_open,
@@ -1769,6 +1777,7 @@ static const struct block_device_operations lo_fops = { 
#ifdef CONFIG_COMPAT

	.compat_ioctl =	lo_compat_ioctl,

#endif

	.free_disk =	lo_free_disk,

};



/*
@@ -2060,15 +2069,14 @@ static void loop_remove(struct loop_device *lo) 
{

	/* Make this loop device unreachable from pathname. */

	del_gendisk(lo->lo_disk);

	blk_cleanup_disk(lo->lo_disk);

	blk_cleanup_queue(lo->lo_disk->queue);

	blk_mq_free_tag_set(&lo->tag_set);



	mutex_lock(&loop_ctl_mutex);

	idr_remove(&loop_index_idr, lo->lo_number);

	mutex_unlock(&loop_ctl_mutex);

	/* There is no route which can find this loop device. */

	mutex_destroy(&lo->lo_mutex);

	kfree(lo);



	put_disk(lo->lo_disk);

}



static void loop_probe(dev_t dev)