+ include-linux-pgtableh-convert-arch_enter_lazy_mmu_mode-and-friends-to-static-inlines.patch added to mm-hotfixes-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: include/linux/pgtable.h: convert arch_enter_lazy_mmu_mode() and friends to static inlines
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     include-linux-pgtableh-convert-arch_enter_lazy_mmu_mode-and-friends-to-static-inlines.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/include-linux-pgtableh-convert-arch_enter_lazy_mmu_mode-and-friends-to-static-inlines.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Andrew Morton <akpm@linux-foundation.org>
Subject: include/linux/pgtable.h: convert arch_enter_lazy_mmu_mode() and friends to static inlines
Date: Sat Sep 13 05:03:39 PM PDT 2025

commit c519c3c0a113 ("mm/kasan: avoid lazy MMU mode hazards") introduced
the use of arch_enter_lazy_mmu_mode(), which results in the compiler
complaining about "statement has no effect", when
__HAVE_ARCH_LAZY_MMU_MODE is not defined in include/linux/pgtable.h

The exact warning/error is:

In file included from ./include/linux/kasan.h:37,
                 from mm/kasan/shadow.c:14:
mm/kasan/shadow.c: In function kasan_populate_vmalloc_pte:
./include/linux/pgtable.h:247:41: error: statement with no effect [-Werror=unused-value]
  247 | #define arch_enter_lazy_mmu_mode()      (LAZY_MMU_DEFAULT)
      |                                         ^
mm/kasan/shadow.c:322:9: note: in expansion of macro arch_enter_lazy_mmu_mode>   322 |         arch_enter_lazy_mmu_mode();
     |         ^~~~~~~~~~~~~~~~~~~~~~~~

switching these "functions" to static inlines fixes this up.

Fixes: c519c3c0a113 ("mm/kasan: avoid lazy MMU mode hazards") 
Reported-by: Balbir Singh <balbirs@nvidia.com>
Closes: https://lkml.kernel.org/r/20250912235515.367061-1-balbirs@nvidia.com
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/pgtable.h |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/include/linux/pgtable.h~include-linux-pgtableh-convert-arch_enter_lazy_mmu_mode-and-friends-to-static-inlines
+++ a/include/linux/pgtable.h
@@ -232,9 +232,9 @@ static inline int pmd_dirty(pmd_t pmd)
  * and the mode cannot be used in interrupt context.
  */
 #ifndef __HAVE_ARCH_ENTER_LAZY_MMU_MODE
-#define arch_enter_lazy_mmu_mode()	do {} while (0)
-#define arch_leave_lazy_mmu_mode()	do {} while (0)
-#define arch_flush_lazy_mmu_mode()	do {} while (0)
+static inline void arch_enter_lazy_mmu_mode(void) {}
+static inline void arch_leave_lazy_mmu_mode(void) {}
+static inline void arch_flush_lazy_mmu_mode(void) {}
 #endif
 
 #ifndef pte_batch_hint
_

Patches currently in -mm which might be from akpm@linux-foundation.org are

include-linux-pgtableh-convert-arch_enter_lazy_mmu_mode-and-friends-to-static-inlines.patch
mm-page_vma_mapped-track-if-the-page-is-mapped-across-page-table-boundary-fix.patch
mm-rmap-fix-a-mlock-race-condition-in-folio_referenced_one-fix.patch
mm-rmap-mlock-large-folios-in-try_to_unmap_one-fix.patch
mm-vmscan-remove-folio_test_private-check-in-pageout-fix.patch
kho-add-support-for-preserving-vmalloc-allocations-checkpatch-fixes.patch