# Re: \[PATCH v3 01/14\] memory-failure: fetch compound\_head after pgmap\_pfn\_valid()

- From: Dan Williams \<hidden\>
- Date: 2021-07-15 00:18:12 
- List: linux-doc
- Page: https://ratatoskr.run/linux-doc/2021/07/6509834
- Thread: https://ratatoskr.run/linux-mm/2021/07/6509813/t.md

```text
On Wed, Jul 14, 2021 at 12:36 PM Joao Martins [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>
```