On Mon, Sep 09, 2019 at 06:13:31PM +0200, Christoph Hellwig wrote:
> On Mon, Sep 09, 2019 at 02:56:56PM +0200, Thierry Reding wrote:
> > From: Thierry Reding <treding@xxxxxxxxxx>
> >
> > When enabling the DMA map merging capability for a queue, ensure that
> > the maximum segment size does not exceed the device's limit.
>
> We can't do that unfortunately. If we use the virt_boundary setting
> we do aggressive merges that there is no accounting for. So we can't
> limit the segment size.
Could you explain a bit why we can't do that?
The segment size limit is basically removed since the following commit
200a9aff7b02 ("block: remove the segment size check in bio_will_gap").
Before that commit, the max segment size limit worked.
Thanks,
Ming
