On 1/23/23 19:08, John Hubbard wrote:

On 1/23/23 09:30, David Howells wrote:

quoted

Renumber FOLL_PIN and FOLL_GET down to bit 0 and 1 respectively so that
they are coincidentally the same as BIO_PAGE_PINNED and BIO_PAGE_REFFED and
also so that they can be stored in the bottom two bits of a page pointer
(something I'm looking at for zerocopy socket fragments).

(Note that BIO_PAGE_REFFED should probably be got rid of at some point,
hence why FOLL_PIN is at 0.)

Also renumber down the other FOLL_* flags to close the gaps.

Should we also get these sorted into internal-to-mm and public sets?
Because Jason (+Cc) again was about to split them apart into
mm/internal.h [1] and that might make that a little cleaner.

I see that I omitted both Jason's Cc and the reference, so I'll resend.
Sorry for the extra noise.

[1] https://lore.kernel.org/all/fcdb3294-3740-a0e0-b115-12842eb0696d@nvidia.com/ (local)

Also, I don't think that there is any large readability difference
either way between 0x and <<1, so whatever you and Christophe settle on
there seems fine.

So either way with those points,

Reviewed-by: John Hubbard <jhubbard@nvidia.com>

thanks,

thanks,
-- 
John Hubbard
NVIDIA