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

[Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>]

On Thu, Oct 2, 2025 at 11:19 PM Andrew Morton <akpm@linux-foundation.org> wrote:
>
> No idea.  Let me cc rust-for-linux.
>
> It's a one-line patch:
>
> --- a/include/linux/mm.h~mm-ksm-fix-flag-dropping-behavior-in-ksm_madvise
> +++ a/include/linux/mm.h
> @@ -296,7 +296,7 @@ extern unsigned int kobjsize(const void
>  #define VM_MIXEDMAP    0x10000000      /* Can contain "struct page" and pure PFN pages */
>  #define VM_HUGEPAGE    0x20000000      /* MADV_HUGEPAGE marked this vma */
>  #define VM_NOHUGEPAGE  0x40000000      /* MADV_NOHUGEPAGE marked this vma */
> -#define VM_MERGEABLE   0x80000000      /* KSM may merge identical pages */
> +#define VM_MERGEABLE   BIT(31)         /* KSM may merge identical pages */
>
>  #ifdef CONFIG_ARCH_USES_HIGH_VMA_FLAGS
>  #define VM_HIGH_ARCH_BIT_0     32      /* bit only usable on 64-bit architectures */

Yeah, non-trivial macros confuse `bindgen`.

For the moment, you can do e.g. [1].

Other times, we have changed `#define`s into `enum`s -- that also works.

I hope that helps.

Cheers,
Miguel

[1]

diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index 5128e2f12038..918f4c74067b 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -106,3 +106,5 @@ const xa_mark_t RUST_CONST_HELPER_XA_PRESENT = XA_PRESENT;

 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;