On Wed 16-03-22 09:45:17, Christoph Hellwig wrote:
> 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>
Looks good. Feel free to add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> 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 0813f63d5bbd2..cbaa18bcad1fe 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -1765,6 +1765,14 @@ 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,
> @@ -1773,6 +1781,7 @@ static const struct block_device_operations lo_fops = {
> #ifdef CONFIG_COMPAT
> .compat_ioctl = lo_compat_ioctl,
> #endif
> + .free_disk = lo_free_disk,
> };
>
> /*
> @@ -2064,14 +2073,13 @@ 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)
> --
> 2.30.2
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
