From: Christoph Hellwig <hch@xxxxxx> [ Upstream commit d2c7f56f8b5256d57f9e3fc7794c31361d43bdd9 ] 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: Christoph Hellwig <hch@xxxxxx> Reviewed-by: Jan Kara <jack@xxxxxxx> Link: https://lore.kernel.org/r/20220330052917.2566582-12-hch@xxxxxx Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/block/loop.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index a58595f5ee2c..ed7bec11948c 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1768,6 +1768,14 @@ 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, @@ -1776,6 +1784,7 @@ static const struct block_device_operations lo_fops = { #ifdef CONFIG_COMPAT .compat_ioctl = lo_compat_ioctl, #endif + .free_disk = lo_free_disk, }; /* @@ -2090,15 +2099,14 @@ 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) -- 2.35.1
