Re: [PATCH v5 4/6] io_uring: rsrc: delegate VMA file-backed check to GUP

[David Hildenbrand]

On 15.05.23 21:55, Jens Axboe wrote:
> On 5/14/23 3:26 PM, Lorenzo Stoakes wrote:
> > Now that the GUP explicitly checks FOLL_LONGTERM pin_user_pages() for
> > broken file-backed mappings in "mm/gup: disallow FOLL_LONGTERM GUP-nonfast
> > writing to file-backed mappings", there is no need to explicitly check VMAs
> > for this condition, so simply remove this logic from io_uring altogether.
>
> Don't have the prerequisite patch handy (not in mainline yet), but if it
> just moves the check, then:
>
> Reviewed-by: Jens Axboe <axboe@xxxxxxxxx>

Jens, please see my note regarding iouring:

https://lore.kernel.org/bpf/6e96358e-bcb5-cc36-18c3-ec5153867b9a@xxxxxxxxxx/

With this patch, MAP_PRIVATE will work as expected (2), but there will 
be a change in return code handling (1) that we might have to document
in the man page.

--
Thanks,

David / dhildenb