On Wed, Jul 14, 2021 at 12:36 PM Joao Martins [off-list ref] wrote:

memory_failure_dev_pagemap() at the moment assumes base pages (e.g.
dax_lock_page()).  For pagemap with compound pages fetch the
compound_head in case a tail page memory failure is being handled.

Currently this is a nop, but in the advent of compound pages in
dev_pagemap it allows memory_failure_dev_pagemap() to keep working.

Reported-by: Jane Chu <redacted>
Signed-off-by: Joao Martins <redacted>
Reviewed-by: Naoya Horiguchi <redacted>

Reviewed-by: Dan Williams <redacted>