Re: [linux-next:master 13069/13300] error[E0425]: cannot find value `VM_MERGEABLE` in crate `bindings`

[Jakub Acs <acsjakub@amazon.de>]

On Thu, Oct 02, 2025 at 05:24:48PM -0700, John Hubbard wrote:
> On 10/2/25 3:43 PM, Andrew Morton wrote:
> > On Fri, 3 Oct 2025 00:39:16 +0200 Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> wrote:
> >> On Fri, Oct 3, 2025 at 12:27 AM Andrew Morton <akpm@linux-foundation.org> wrote:
> ...
> > From: Andrew Morton <akpm@linux-foundation.org>
> > Subject: mm-ksm-fix-flag-dropping-behavior-in-ksm_madvise-fix
> > Date: Thu Oct  2 03:37:47 PM PDT 2025
> > 
> > Rust bindgen wasn't able to handle the BIT() macro.  Add a helper (from
> > Miguel) to fix this.
> > 
> > Reported-by: kernel test robot <lkp@intel.com>
> > Closes: https://lore.kernel.org/oe-kbuild-all/202510030449.VfSaAjvd-lkp@intel.com/
> > Cc: Axel Rasmussen <axelrasmussen@google.com>
> > Cc: Chengming Zhou <chengming.zhou@linux.dev>
> > Cc: David Hildenbrand <david@redhat.com>
> > Cc: Jakub Acs <acsjakub@amazon.de>
> > Cc: Peter Xu <peterx@redhat.com>
> > Cc: SeongJae Park <sj@kernel.org>
> > Cc: Xu Xin <xu.xin16@zte.com.cn>
> > Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
> > Cc: Alice Ryhl <aliceryhl@google.com>
> > Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> > ---
> > 
> >  rust/bindings/bindings_helper.h |    1 +
> >  1 file changed, 1 insertion(+)
> > 
> > --- a/rust/bindings/bindings_helper.h~mm-ksm-fix-flag-dropping-behavior-in-ksm_madvise-fix
> > +++ a/rust/bindings/bindings_helper.h
> > @@ -99,3 +99,4 @@ const xa_mark_t RUST_CONST_HELPER_XA_PRE
> >  
> >  const gfp_t RUST_CONST_HELPER_XA_FLAGS_ALLOC = XA_FLAGS_ALLOC;
> >  const gfp_t RUST_CONST_HELPER_XA_FLAGS_ALLOC1 = XA_FLAGS_ALLOC1;
> > +const vm_flags_t RUST_CONST_HELPER_VM_MERGEABLE = VM_MERGEABLE;
> > _
> 
> Yes, this fixes the build on my system too, so:
> 
> Tested-by: John Hubbard <jhubbard@nvidia.com>
> 
> ...of course, we'll have to undo this later, as part of the fix
> for the Rust for Linux build system, to handle BIT() and similar
> macros in bindgen.
> 

Hi, 

sorry for the issues this has caused. We're also changing the other
defines to BIT() for consistency, it was applied to mm-new in [1]. I
assume this will have the same breaking effect. Not sure what is the
solution - whether to wait for the fix mentioned by John or add similar
defintions to a/rust/bindings/bindings_helper.h for all consts?

[1]: https://lore.kernel.org/all/20251002202112.C2293C4CEF4@smtp.kernel.org/

Kind Regards,
Jakub



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