Re: [PATCH v2 3/5] mm: userfaultfd: combine 'mode' and 'wp_copy' arguments

From: James Houghton
Date: Thu Feb 23 2023 - 12:32:11 EST


On Wed, Feb 22, 2023 at 4:58 PM Axel Rasmussen <axelrasmussen@xxxxxxxxxx> wrote:
>
> Many userfaultfd ioctl functions take both a 'mode' and a 'wp_copy'
> argument. In future commits we plan to plumb the flags through to more
> places, so we'd be proliferating the very long argument list even
> further.
>
> Let's take the time to simplify the argument list. Combine the two
> arguments into one - and generalize, so when we add more flags in the
> future, it doesn't imply more function arguments.
>
> Since the modes (copy, zeropage, continue) are mutually exclusive, store
> them as an integer value (0, 1, 2) in the low bits. Place combine-able
> flag bits in the high bits.
>
> Signed-off-by: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>

Acked-by: James Houghton <jthoughton@xxxxxxxxxx>

I don't see anything wrong with this patch. Thanks, Axel.