block: Fix discard topology stacking and reporting

In some cases we would end up stacking discard_zeroes_data incorrectly.
Fix this by enabling the feature by default for stacking drivers and
clearing it for low-level drivers. Incorporating a device that does not
support dzd will then cause the feature to be disabled in the stacking
driver.

Also ensure that the maximum discard value does not overflow when
exported in sysfs and return 0 in the alignment and dzd fields for
devices that don't support discard.

Reported-by: Lukas Czerner <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>
Acked-by: Mike Snitzer <[email protected]>
Cc: [email protected]
Signed-off-by: Jens Axboe <[email protected]>

0 files changed, 0 insertions, 0 deletions