Re: [PATCH 2/5] memstick/ms_block: simplify refcounting

On Wed, Feb 09, 2022 at 09:21:17AM +0100, Christoph Hellwig wrote:

Implement the ->free_disk method to free the msb_data structure only once
the last gendisk reference goes away instead of keeping a local refcount.

The approach looks good, just the error handling needs to be careful,
such as, once driver data is bound to disk->private_data, the previous
error handling code shouldn't touch/free the driver data any more. That
said assigning disk->private_data implies driver data ownership transfer
after this conversion.

Such as, in msb_init_disk(), once blk_cleanup_disk() is done, the code
branch of out_release_id shouldn't be run; msb_probe() has the similar
issue too.

Thanks,
Ming