On Tue, Jun 26 2018 at  3:07pm -0400,
Dan Williams [off-list ref] wrote:

On Tue, Jun 26, 2018 at 11:58 AM, Mike Snitzer [off-list ref] wrote:

quoted

On Tue, Jun 26 2018 at  2:52pm -0400,
Dan Williams [off-list ref] wrote:

quoted

On Tue, Jun 26, 2018 at 10:59 AM, Ross Zwisler
[off-list ref] wrote:

quoted

QUEUE_FLAG_DAX is an indication that a given block device supports
filesystem DAX and should not be set for PMEM namespaces which are in "raw"
or "sector" modes.  These namespaces lack struct page and are prevented
from participating in filesystem DAX.

Signed-off-by: Ross Zwisler <redacted>
Suggested-by: Mike Snitzer <redacted>
Cc: stable@vger.kernel.org

Why is this cc: stable? What is the user visible impact of this change
especially given the requirement to validate QUEUE_FLAG_DAX with
bdev_dax_supported()? Patch looks good, but it's just a cosmetic fixup
afaics.

This isn't cosmetic when you consider that stacking up a DM device is
looking at this flag to determine whether a table does or does _not_
support DAX.

So this patch, in conjunction with the other changes in the series, is
certainly something I'd consider appropriate for stable.

I think this classifies as something that never worked correctly and
is not a regression. It does not identify which commit it is repairing
or the user visible failure mode.

So you're taking issue with making stacked dax configs work in older
kernels?  That's fine.  We can drop the stable cc if you like.

But I mean we intended for this to work.. so the Fixes commit references
can easily be added, e.g.: 545ed20e6df68a4d2584a29a2a28ee8b2f7e9547
("dm: add infrastructure for DAX support")