Re: [PATCH] mm: add some missing includes to mm-local headers

Re: [PATCH] mm: add some missing includes to mm-local headers

[Lorenzo Stoakes (ARM)]

On Tue, Aug 04, 2026 at 12:45:22PM +0200, David Hildenbrand (Arm) wrote:
> On 8/4/26 12:08, Lorenzo Stoakes (ARM) wrote:
> > There are a number of internal headers local to mm/ which reference
> > functions and data types without including the relevant headers.
> >
> > mm/vma.h is a special case that intentionally does not include additional
> > headers, but the others are not.
> >
> > This breaks tooling like clangd (which is where I noticed this), though the
> > build is OK due to the C files including the headers happening to include
> > required dependencies.
> >
> > It's better to be explicit about dependencies anyway, so add the missing
> > includes and fix clangd as a bonus.
>
> I'm curious, how did you identify these? The mm/vmalloc.h is rather easy, but I wonder about
> e.g., mm/shuffle.h including mmzone.h.

Well I got AI to look them up ;) but I pared down what it gave me to a simpler
subset and checked everything so I don't consider myself in a state of
slopper-sin :)

[this kind of check ideas, look things up stuff I don't consider warrants an
Assisted-by tag btw].

The headers for everything but shuffle.h are obvious, so that's the tricky one -
it's for pg_data_t and struct zone specifically.

How I discovered this with clangd initially was - Do something like 'C-c l g r' or
'C-c l g g' in emacs via LSP and it reports 'no symbols' for something I _know_ is
compiled in.

>
> --
> Cheers,
>
> David

--
Cheers, Lorenzo

Re: [PATCH] mm: add some missing includes to mm-local headers

[Lorenzo Stoakes (ARM)]

On Tue, Aug 04, 2026 at 12:51:40PM +0200, David Hildenbrand (Arm) wrote:
> On 8/4/26 12:45, David Hildenbrand (Arm) wrote:
> > On 8/4/26 12:08, Lorenzo Stoakes (ARM) wrote:
> >> There are a number of internal headers local to mm/ which reference
> >> functions and data types without including the relevant headers.
> >>
> >> mm/vma.h is a special case that intentionally does not include additional
> >> headers, but the others are not.
> >>
> >> This breaks tooling like clangd (which is where I noticed this), though the
> >> build is OK due to the C files including the headers happening to include
> >> required dependencies.
> >>
> >> It's better to be explicit about dependencies anyway, so add the missing
> >> includes and fix clangd as a bonus.
> >
> > I'm curious, how did you identify these? The mm/vmalloc.h is rather easy, but I wonder about
> > e.g., mm/shuffle.h including mmzone.h.
> >
>
> To clarify, I have clangd running behind a vim plugin, and so far it just worked.
>
> I had to generate a weird XML at some point that does magical things for clangd.

Well for me I get the kernel build to generate compiler_commands.json and use
that via:

	scripts/clang-tools/gen_compile_commands.py vmlinux.a arch/x86/boot/

In a build script.

But maybe I need your weird XML... I do get frustrated that it limits things to
what I happened to compile. It'd be nice to get it to index literally everything
somehow.

>
> So I'm curious how to invoke clangd manually to actually get these reports.

See other reply, it's just that I noticed missing symbols.

Actually this happened with vma.h (I sloppily got AI to figure out any other
cases) which _intentionally_ doesn't have includes.

But clangd lets you work around that in .clangd:

If:
  PathMatch: mm/vma\.h
CompileFlags:
  Add: [-include, mm/vma_internal.h]

:)

>
> --
> Cheers,
>
> David

--
Cheers, Lorenzo

Re: [PATCH] mm: add some missing includes to mm-local headers

[David Hildenbrand (Arm)]

On 8/4/26 13:05, Lorenzo Stoakes (ARM) wrote:
> On Tue, Aug 04, 2026 at 12:51:40PM +0200, David Hildenbrand (Arm) wrote:
>> On 8/4/26 12:45, David Hildenbrand (Arm) wrote:
>>>
>>> I'm curious, how did you identify these? The mm/vmalloc.h is rather easy, but I wonder about
>>> e.g., mm/shuffle.h including mmzone.h.
>>>
>>
>> To clarify, I have clangd running behind a vim plugin, and so far it just worked.
>>
>> I had to generate a weird XML at some point that does magical things for clangd.
> 
> Well for me I get the kernel build to generate compiler_commands.json and use
> that via:
> 
> 	scripts/clang-tools/gen_compile_commands.py vmlinux.a arch/x86/boot/
> 
> In a build script.
> 
> But maybe I need your weird XML... I do get frustrated that it limits things to
> what I happened to compile. It'd be nice to get it to index literally everything
> somehow.

Nah, it was that magical json I had in mind.

> 
>>
>> So I'm curious how to invoke clangd manually to actually get these reports.
> 
> See other reply, it's just that I noticed missing symbols.
> 
> Actually this happened with vma.h (I sloppily got AI to figure out any other
> cases) which _intentionally_ doesn't have includes.
> 
> But clangd lets you work around that in .clangd:
> 
> If:
>   PathMatch: mm/vma\.h
> CompileFlags:
>   Add: [-include, mm/vma_internal.h]
> 
> :)
I was hoping for an easy-to-run script that complains, instead of people just randomly
running into "missing symbols" and then having to fix it.

But there doesn't seem to be a low hanging fruit.

-- 
Cheers,

David

Re: [PATCH] mm: add some missing includes to mm-local headers

[David Hildenbrand (Arm)]

On 8/4/26 13:02, Lorenzo Stoakes (ARM) wrote:
> On Tue, Aug 04, 2026 at 12:45:22PM +0200, David Hildenbrand (Arm) wrote:
>> On 8/4/26 12:08, Lorenzo Stoakes (ARM) wrote:
>>> There are a number of internal headers local to mm/ which reference
>>> functions and data types without including the relevant headers.
>>>
>>> mm/vma.h is a special case that intentionally does not include additional
>>> headers, but the others are not.
>>>
>>> This breaks tooling like clangd (which is where I noticed this), though the
>>> build is OK due to the C files including the headers happening to include
>>> required dependencies.
>>>
>>> It's better to be explicit about dependencies anyway, so add the missing
>>> includes and fix clangd as a bonus.
>>
>> I'm curious, how did you identify these? The mm/vmalloc.h is rather easy, but I wonder about
>> e.g., mm/shuffle.h including mmzone.h.
> 
> Well I got AI to look them up ;) but I pared down what it gave me to a simpler
> subset and checked everything so I don't consider myself in a state of
> slopper-sin :)
> 
> [this kind of check ideas, look things up stuff I don't consider warrants an
> Assisted-by tag btw].
> 
> The headers for everything but shuffle.h are obvious, so that's the tricky one -
> it's for pg_data_t and struct zone specifically.
> 
> How I discovered this with clangd initially was - Do something like 'C-c l g r' or
> 'C-c l g g' in emacs via LSP and it reports 'no symbols' for something I _know_ is
> compiled in.

emacs ...  there's your problem :P

Thanks for the explanation, I'm afraid this might become a whack-a-mole without
a proper way to detect this automatically. But that does not really seem doable
easily.

Acked-by: David Hildenbrand (Arm) <david@kernel.org>

-- 
Cheers,

David

Re: [PATCH] mm: add some missing includes to mm-local headers

[Zi Yan]

On 4 Aug 2026, at 6:08, Lorenzo Stoakes (ARM) wrote:

> There are a number of internal headers local to mm/ which reference
> functions and data types without including the relevant headers.
>
> mm/vma.h is a special case that intentionally does not include additional
> headers, but the others are not.
>
> This breaks tooling like clangd (which is where I noticed this), though the
> build is OK due to the C files including the headers happening to include
> required dependencies.
>
> It's better to be explicit about dependencies anyway, so add the missing
> includes and fix clangd as a bonus.
>
> Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
> ---
>  mm/cma.h           | 1 +
>  mm/hugetlb_cma.h   | 2 ++
>  mm/memcontrol-v1.h | 1 +
>  mm/pgalloc-track.h | 3 +++
>  mm/shuffle.h       | 2 ++
>  mm/swap.h          | 1 +
>  mm/vmalloc.h       | 2 ++
>  7 files changed, 12 insertions(+)
>

Acked-by: Zi Yan <ziy@nvidia.com>

Best Regards,
Yan, Zi

Re: [PATCH] mm: add some missing includes to mm-local headers

[Barry Song]

On Tue, Aug 4, 2026 at 6:09 PM Lorenzo Stoakes (ARM) <ljs@kernel.org> wrote:
>
> There are a number of internal headers local to mm/ which reference
> functions and data types without including the relevant headers.
>
> mm/vma.h is a special case that intentionally does not include additional
> headers, but the others are not.
>
> This breaks tooling like clangd (which is where I noticed this), though the
> build is OK due to the C files including the headers happening to include
> required dependencies.
>
> It's better to be explicit about dependencies anyway, so add the missing
> includes and fix clangd as a bonus.
>
> Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
> ---

Reviewed-by: Barry Song <baohua@kernel.org>

Re: [PATCH] mm: add some missing includes to mm-local headers

[Baoquan He]

On 08/04/26 at 11:08am, Lorenzo Stoakes (ARM) wrote:
> There are a number of internal headers local to mm/ which reference
> functions and data types without including the relevant headers.
> 
> mm/vma.h is a special case that intentionally does not include additional
> headers, but the others are not.
> 
> This breaks tooling like clangd (which is where I noticed this), though the
> build is OK due to the C files including the headers happening to include
> required dependencies.
> 
> It's better to be explicit about dependencies anyway, so add the missing
> includes and fix clangd as a bonus.
> 
> Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
> ---
>  mm/cma.h           | 1 +
>  mm/hugetlb_cma.h   | 2 ++
>  mm/memcontrol-v1.h | 1 +
>  mm/pgalloc-track.h | 3 +++
>  mm/shuffle.h       | 2 ++
>  mm/swap.h          | 1 +
>  mm/vmalloc.h       | 2 ++
>  7 files changed, 12 insertions(+)

Reviewed-by: Baoquan He <baoquan.he@linux.dev>

> 
> diff --git a/mm/cma.h b/mm/cma.h
> index c70180c36559..ab6d39898ea5 100644
> --- a/mm/cma.h
> +++ b/mm/cma.h
> @@ -2,6 +2,7 @@
>  #ifndef __MM_CMA_H__
>  #define __MM_CMA_H__
>  
> +#include <linux/cma.h>
>  #include <linux/debugfs.h>
>  #include <linux/kobject.h>
>  
> diff --git a/mm/hugetlb_cma.h b/mm/hugetlb_cma.h
> index 3aa483573d17..730b2b4965b6 100644
> --- a/mm/hugetlb_cma.h
> +++ b/mm/hugetlb_cma.h
> @@ -2,6 +2,8 @@
>  #ifndef _LINUX_HUGETLB_CMA_H
>  #define _LINUX_HUGETLB_CMA_H
>  
> +#include <linux/hugetlb.h>
> +
>  #ifdef CONFIG_CMA
>  void hugetlb_cma_free_frozen_folio(struct folio *folio);
>  struct folio *hugetlb_cma_alloc_frozen_folio(int order, gfp_t gfp_mask,
> diff --git a/mm/memcontrol-v1.h b/mm/memcontrol-v1.h
> index 0f703f239c80..1e394269c613 100644
> --- a/mm/memcontrol-v1.h
> +++ b/mm/memcontrol-v1.h
> @@ -4,6 +4,7 @@
>  #define __MM_MEMCONTROL_V1_H
>  
>  #include <linux/cgroup-defs.h>
> +#include <linux/memcontrol.h>
>  
>  /* Cgroup v1 and v2 common declarations */
>  
> diff --git a/mm/pgalloc-track.h b/mm/pgalloc-track.h
> index e9e879de8649..1a6de1358a21 100644
> --- a/mm/pgalloc-track.h
> +++ b/mm/pgalloc-track.h
> @@ -2,6 +2,9 @@
>  #ifndef _LINUX_PGALLOC_TRACK_H
>  #define _LINUX_PGALLOC_TRACK_H
>  
> +#include <linux/mm.h>
> +#include <linux/pgtable.h>
> +
>  #if defined(CONFIG_MMU)
>  static inline p4d_t *p4d_alloc_track(struct mm_struct *mm, pgd_t *pgd,
>  				     unsigned long address,
> diff --git a/mm/shuffle.h b/mm/shuffle.h
> index 61bbcddeeee6..11bec7521ab8 100644
> --- a/mm/shuffle.h
> +++ b/mm/shuffle.h
> @@ -2,7 +2,9 @@
>  // Copyright(c) 2018 Intel Corporation. All rights reserved.
>  #ifndef _MM_SHUFFLE_H
>  #define _MM_SHUFFLE_H
> +
>  #include <linux/jump_label.h>
> +#include <linux/mmzone.h>
>  
>  #define SHUFFLE_ORDER MAX_PAGE_ORDER
>  
> diff --git a/mm/swap.h b/mm/swap.h
> index d077e5893a42..ec580c713204 100644
> --- a/mm/swap.h
> +++ b/mm/swap.h
> @@ -5,6 +5,7 @@
>  #include <linux/atomic.h> /* for atomic_long_t */
>  #include <linux/mm.h> /* for PAGE_SHIFT */
>  #include <linux/memcontrol.h> /* for mem_cgroup_swappiness() */
> +#include <linux/swap.h> /* for MAX_SWAPFILES_SHIFT, struct swap_info_struct */
>  
>  struct mempolicy;
>  struct swap_iocb;
> diff --git a/mm/vmalloc.h b/mm/vmalloc.h
> index dcfe30eaa80c..8866ddcff668 100644
> --- a/mm/vmalloc.h
> +++ b/mm/vmalloc.h
> @@ -5,6 +5,8 @@
>  #ifndef __MM_VMALLOC_H
>  #define __MM_VMALLOC_H
>  
> +#include <linux/vmalloc.h>
> +
>  #ifdef CONFIG_MMU
>  void __init vmalloc_init(void);
>  int __must_check vmap_pages_range_noflush(unsigned long addr, unsigned long end,
> 
> ---
> base-commit: e47602c51d20a93fa1711ed896dc9480de4374d9
> change-id: 20260804-fix-some-local-headers-0ebc15f34c72
> 
> Cheers,
> -- 
> Lorenzo Stoakes (ARM) <ljs@kernel.org>
>