Re: [PATCH] ioctl_userfaultfd.2: Corrections for returned .ioctls members

From: Ian Abbott
Date: Tue Mar 22 2022 - 12:46:44 EST


On 22/03/2022 16:36, Axel Rasmussen wrote:
On Tue, Mar 22, 2022 at 9:23 AM Axel Rasmussen <axelrasmussen@xxxxxxxxxx> wrote:

On Tue, Mar 22, 2022 at 5:32 AM Alejandro Colomar (man-pages)
<alx.manpages@xxxxxxxxx> wrote:

Hi Ian and Peter,

On 3/21/22 07:10, Peter Xu wrote:
On Fri, Mar 18, 2022 at 07:13:43PM +0000, Ian Abbott wrote:
Support for the `UFFDIO_WRITEPROTECT` operation is not indicated in the
`ioctls` member of `struct uffdio_api`. It is indicated in the `ioctls`
member of `struct uffdio_register` along with indications of support for
the `UFFDIO_COPY`, `UFFDIO_WAKE` and `UFFDIO_ZEROPAGE` operations (and
also the `UFFDIO_CONTINUE` operation supported since Linux 5.13 but
that is not documented by this man page yet.)

I thought it should have landed but indeed it's not. Copying Axel.

Ah, I mistakenly thought it got merged, but there were a few remaining
issues Alejandro wanted addressed first. I'll send a v3 of it later
today.

For what it's worth, as part of adding minor fault handling, we pretty
significantly change the ioctl field's behavior, and I rewrote a lot
of the documentation around it. So, it may conflict with this patch.
:/ Sorry about that.

Heh, I spoke too soon. My patch doesn't touch this after all, I think
the patches don't conflict. :) It's been a while since I looked at
it...

I guess the section (in my patch) that indicates supported ioctls in `struct uffdio_register` would still need tweaking to mention `UFFDIO_CONTINUE` though, so either one of the patches will need to change or another little patch will be needed.

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