Re: [PATCH] nvme: honor NVME_QUIRK_DEALLOCATE_ZEROES for unmap Write Zeroes

[Robert Pang]

Hi Zhang Yi

On Tue, Mar 10, 2026 at 7:56 PM Zhang Yi <yi.zhang@xxxxxxxxxxxxxxx> wrote:
>
> Hi Robert,
>
> On 3/11/2026 1:14 AM, Robert Pang wrote:
> > Hi Christoph
> >
> > On Fri, Mar 6, 2026 at 6:24 AM Christoph Hellwig <hch@xxxxxx> wrote:
> >>
> >> On Thu, Mar 05, 2026 at 12:27:32PM -0800, Robert Pang wrote:
> >>> However, certain devices already use the NVME_QUIRK_DEALLOCATE_ZEROES quirk to
> >>> indicate that they deterministically return zeroes after a deallocate/discard
> >>
> >> Those certain devices are completely obsolete first generation Intel
> >> SSDs.
> >>
> >>> Update nvme_update_disk_info() to allow the presence of the DEALLOCATE_ZEROES
> >>> quirk (combined with DSM support) to set max_hw_wzeroes_unmap_sectors to enable
> >>
> >> No. This was a hack that got sneaked in in the first days of the nvme
> >> driver and never should have been there.  It most certainly should not
> >> be extended to any new functionality.
> >>
> >
> > Thank you for your review and for providing the historical context
> > regarding this quirk. Given these insights, we can discard this patch
> > proposal.
> >
>
> I just wonder if you have such hardware and use cases, or if you simply
> want to supplement this feature for those corner devices?
>

It is the latter.

Best regards
Robert Pang

> Best regards
> Yi.