Re: [PATCH 1/1] s390/dasd: remove ioctl_by_bdev from DASD driver

[Christoph Hellwig]

On Thu, Apr 30, 2020 at 01:17:54PM +0200, Stefan Haberland wrote:
> Remove the calls to ioctl_by_bdev from the DASD partition detection code
> to enable the removal of the specific code.
> 
> To do so reuse the gendisk private_data pointer and not only provide a
> pointer to the devmap but provide a new structure containing a pointer
> to the devmap as well as all required information for the partition
> detection. This makes it independent from the dasd_information2_t
> structure.

I think sharing the data structure in private data is pretty dangerous.
In the meantime I thought of another idea - the partition code could
do a symbol_get of a symbol exported by the dasd driver and use that
to query the information.