Re: [PATCH v4 2/2] s390/dasd: remove ioctl_by_bdev calls

[Christian Borntraeger]

On 07.10.20 12:39, Christoph Hellwig wrote:
> On Wed, Oct 07, 2020 at 11:34:17AM +0200, Christian Borntraeger wrote:
>>
>> On 19.05.20 16:22, Stefan Haberland wrote:
>>> The IBM partition parser requires device type specific information only
>>> available to the DASD driver to correctly register partitions. The
>>> current approach of using ioctl_by_bdev with a fake user space pointer
>>> is discouraged.
>>>
>>> Fix this by replacing IOCTL calls with direct in-kernel function calls.
>>>
>>> Suggested-by: Christoph Hellwig <hch@xxxxxx>
>>> Signed-off-by: Stefan Haberland <sth@xxxxxxxxxxxxx>
>>> Reviewed-by: Jan Hoeppner <hoeppner@xxxxxxxxxxxxx>
>>> Reviewed-by: Peter Oberparleiter <oberpar@xxxxxxxxxxxxx>
>>
>> FWIW, this broken the ibm-partition code for virtio-blk, when CONFIG_DASD=m.
> 
> What are the symptoms?

During boot I normally have
 
[    0.930231] virtio_blk virtio1: [vda] 5409180 4096-byte logical blocks (22.2 GB/20.6 GiB)
[    0.930233] vda: detected capacity change from 0 to 22156001280
[    0.932806]  vda:VOL1/  0X3333: vda1 vda2 vda3

With this change, the last line is no longer there (if CONFIG_DASD=m) and this also 
reflects itself in /proc/partitions. The partitions are no longer detected.