Re: [PATCH 02/10] block: virtio-blk: check logical block size

["Martin K. Petersen" <martin.petersen@oracle.com>]

Hi Maxim,

> Instead of this adding blk_is_valid_logical_block_size allowed me to
> trivially convert most of the uses.
>
> For RFC I converted only some drivers that I am more familiar with
> and/or can test but I can remove the driver's own checks in most other
> drivers with low chance of introducing a bug, even if I can't test the
> driver.
>
> What do you think?
>
> I can also both make blk_queue_logical_block_size return an error
> value, and have blk_is_valid_logical_block_size and use either of
> these checks, depending on the driver with eventual goal of
> un-exporting blk_is_valid_logical_block_size.

My concern is that blk_is_valid_logical_block_size() deviates from the
regular block layer convention where the function to set a given queue
limit will either adjust the passed value or print a warning.

I guess I won't entirely object to having the actual check in a helper
function that drivers with a peculiar initialization pattern can
use. And then make blk_queue_logical_block_size() call that helper as
well to validate the lbs.

But I do think that blk_queue_logical_block_size() should be the
preferred interface and that, where possible, drivers should be updated
to check the return value of that.

-- 
Martin K. Petersen	Oracle Linux Engineering