Re: [PATCH v2 2/2] x86/mm: Remove unnecessary include in set_memory.h

[Ingo Molnar <mingo@kernel.org>]

* Ingo Molnar <mingo@kernel.org> wrote:

> So I tried to pick up this patch belatedly, but there's more places 
> that mistakenly learned to rely on the stray <linux/mm.h> inclusion, 
> for example on x86 defconfig-ish kernels:
> 
> 
>   In file included from drivers/gpu/drm/i915/gt/intel_ggtt.c:6:
>   ./arch/x86/include/asm/set_memory.h:40:57: error: unknown type name ‘pgprot_t’
>   40 | int __set_memory_prot(unsigned long addr, int numpages, pgprot_t prot);
>   |                                                         ^~~~~~~~

BTW., I did a few touchups to the changelog (see below) - mind picking 
that up once you submit -v2?

Thanks,

	Ingo

======================>
From: Kevin Brodsky <kevin.brodsky@arm.com>
Date: Thu, 12 Dec 2024 08:09:04 +0000
Subject: [PATCH] x86/mm: Reduce header dependencies in <asm/set_memory.h>

Commit:

  03b122da74b2 ("x86/sgx: Hook arch_memory_failure() into mainline code")

... added <linux/mm.h> to <asm/set_memory.h> to provide some helpers.

However the following commit:

  b3fdf9398a16 ("x86/mce: relocate set{clear}_mce_nospec() functions")

... moved the inline definitions someplace else, and now <asm/set_memory.h>
just declares a bunch of mostly self-contained functions.

No need for the whole <linux/mm.h> inclusion to declare functions; just
remove that include. This helps avoid circular dependency headaches
(e.g. if <linux/mm.h> ends up including <linux/set_memory.h>).

This change requires a couple of include fixups not to break the
build:

* <asm/smp.h>: including <asm/thread_info.h> directly relies on
  <linux/thread_info.h> having already been included, because the
  former needs the BAD_STACK/NOT_STACK constants defined in the
  latter. This is no longer the case when <asm/smp.h> is included from
  some driver file - just include <linux/thread_info.h> to stay out
  of trouble.

* sev-guest.c relies on <asm/set_memory.h> including <linux/mm.h>,
  so we just need to make that include explicit.

[ mingo: Cleaned up the changelog ]

Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20241212080904.2089632-3-kevin.brodsky@arm.com
---
 arch/x86/include/asm/set_memory.h       | 1 -
 arch/x86/include/asm/smp.h              | 2 +-
 drivers/virt/coco/sev-guest/sev-guest.c | 1 +
 3 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/set_memory.h b/arch/x86/include/asm/set_memory.h
index cc62ef70ccc0..023994fe6115 100644
--- a/arch/x86/include/asm/set_memory.h
+++ b/arch/x86/include/asm/set_memory.h
@@ -2,7 +2,6 @@
 #ifndef _ASM_X86_SET_MEMORY_H
 #define _ASM_X86_SET_MEMORY_H
 
-#include <linux/mm.h>
 #include <asm/page.h>
 #include <asm-generic/set_memory.h>
 
diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index ca073f40698f..2ca1da5f16d9 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -3,10 +3,10 @@
 #define _ASM_X86_SMP_H
 #ifndef __ASSEMBLY__
 #include <linux/cpumask.h>
+#include <linux/thread_info.h>
 
 #include <asm/cpumask.h>
 #include <asm/current.h>
-#include <asm/thread_info.h>
 
 DECLARE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_sibling_map);
 DECLARE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_core_map);
diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index 264b6523fe52..ddec5677e247 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -23,6 +23,7 @@
 #include <linux/cleanup.h>
 #include <linux/uuid.h>
 #include <linux/configfs.h>
+#include <linux/mm.h>
 #include <uapi/linux/sev-guest.h>
 #include <uapi/linux/psp-sev.h>