[nacked] mm-add-config_sparsemem_classic.patch removed from -mm tree

[nacked] mm-add-config_sparsemem_classic.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm: add CONFIG_SPARSEMEM_CLASSIC
has been removed from the -mm tree.  Its filename was
     mm-add-config_sparsemem_classic.patch

This patch was dropped because it was nacked

------------------------------------------------------
From: Kaitao Cheng <chengkaitao@kylinos.cn>
Subject: mm: add CONFIG_SPARSEMEM_CLASSIC
Date: Sun, 20 Sep 2026 15:04:06 +0800

Several MM paths identify classic sparse memory by testing
CONFIG_SPARSEMEM while also testing that CONFIG_SPARSEMEM_VMEMMAP is
disabled.  Repeating the compound condition obscures the memory model
being selected and requires the local SECTION_IN_PAGE_FLAGS alias for the
same state.

Add CONFIG_SPARSEMEM_CLASSIC as a hidden derived option and use it at the
conditional sites.  Remove SECTION_IN_PAGE_FLAGS and test the new option
directly.

The x86 32-bit vDSO build starts with the x86_64 configuration and then
undefines CONFIG_SPARSEMEM_VMEMMAP to emulate a 32-bit configuration. 
Kconfig-derived symbols are not recomputed by the C preprocessor, so
define CONFIG_SPARSEMEM_CLASSIC there when CONFIG_SPARSEMEM is enabled. 
This preserves the existing behavior.

Link: https://lore.kernel.org/20260920070406.95354-1-kaitao.cheng@linux.dev
Signed-off-by: Kaitao Cheng <chengkaitao@kylinos.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Muchun Song <muchun.song@linux.dev>
---

 arch/x86/entry/vdso/vdso32/fake_32bit_build.h |    3 +++
 include/linux/mm.h                            |   12 ++++--------
 include/linux/mmzone.h                        |    2 +-
 include/linux/page-flags-layout.h             |    2 +-
 mm/Kconfig                                    |    3 +++
 mm/util.c                                     |    2 +-
 6 files changed, 13 insertions(+), 11 deletions(-)

--- a/arch/x86/entry/vdso/vdso32/fake_32bit_build.h~mm-add-config_sparsemem_classic
+++ a/arch/x86/entry/vdso/vdso32/fake_32bit_build.h
@@ -20,6 +20,9 @@
 #define CONFIG_PAGE_OFFSET 0
 #define CONFIG_ILLEGAL_POINTER_VALUE 0
 #define CONFIG_NR_CPUS 1
+#ifdef CONFIG_SPARSEMEM
+#define CONFIG_SPARSEMEM_CLASSIC 1
+#endif
 
 #define BUILD_VDSO32_64
 
--- a/include/linux/mm.h~mm-add-config_sparsemem_classic
+++ a/include/linux/mm.h
@@ -201,7 +201,7 @@ static inline void __mm_zero_struct_page
 extern unsigned long sysctl_user_reserve_kbytes;
 extern unsigned long sysctl_admin_reserve_kbytes;
 
-#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
+#ifdef CONFIG_SPARSEMEM_CLASSIC
 bool page_range_contiguous(const struct page *page, unsigned long nr_pages);
 #else
 static inline bool page_range_contiguous(const struct page *page,
@@ -2531,10 +2531,6 @@ static inline bool is_nommu_shared_vma_f
 }
 #endif
 
-#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
-#define SECTION_IN_PAGE_FLAGS
-#endif
-
 /*
  * The identification function is mainly used by the buddy allocator for
  * determining if two pages could be buddies. We are not really identifying
@@ -2805,7 +2801,7 @@ static inline struct zone *folio_zone(co
 	return &folio_pgdat(folio)->node_zones[folio_zonenum(folio)];
 }
 
-#ifdef SECTION_IN_PAGE_FLAGS
+#ifdef CONFIG_SPARSEMEM_CLASSIC
 static inline void set_page_section(struct page *page, unsigned long section)
 {
 	page->flags.f &= ~(SECTIONS_MASK << SECTIONS_PGSHIFT);
@@ -2823,7 +2819,7 @@ static inline unsigned long memdesc_sect
 	ASSERT_EXCLUSIVE_BITS(mdf->f, SECTIONS_MASK << SECTIONS_PGSHIFT);
 	return (mdf->f >> SECTIONS_PGSHIFT) & SECTIONS_MASK;
 }
-#else /* !SECTION_IN_PAGE_FLAGS */
+#else /* !CONFIG_SPARSEMEM_CLASSIC */
 static inline void set_page_section_from_pfn(struct page *page,
 		unsigned long pfn)
 {
@@ -2833,7 +2829,7 @@ static inline unsigned long memdesc_sect
 {
 	return 0;
 }
-#endif /* SECTION_IN_PAGE_FLAGS */
+#endif /* CONFIG_SPARSEMEM_CLASSIC */
 
 /**
  * folio_pfn - Return the Page Frame Number of a folio.
--- a/include/linux/mmzone.h~mm-add-config_sparsemem_classic
+++ a/include/linux/mmzone.h
@@ -68,7 +68,7 @@
  * memory sections).
  */
 #define MAX_FOLIO_ORDER		MAX_PAGE_ORDER
-#elif defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
+#elif defined(CONFIG_SPARSEMEM_CLASSIC)
 /*
  * Only pages within a single memory section are guaranteed to be
  * contiguous. By limiting folios to a single memory section, all folio
--- a/include/linux/page-flags-layout.h~mm-add-config_sparsemem_classic
+++ a/include/linux/page-flags-layout.h
@@ -49,7 +49,7 @@
  *      " plus space for last_cpupid: | SECTION | NODE | ZONE | LAST_CPUPID ... | FLAGS |
  * classic sparse no space for node:  | SECTION |     ZONE    | ... | FLAGS |
  */
-#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
+#ifdef CONFIG_SPARSEMEM_CLASSIC
 #define SECTIONS_WIDTH		SECTIONS_SHIFT
 #else
 #define SECTIONS_WIDTH		0
--- a/mm/Kconfig~mm-add-config_sparsemem_classic
+++ a/mm/Kconfig
@@ -461,6 +461,9 @@ config SPARSEMEM_VMEMMAP
 	  pfn_to_page and page_to_pfn operations.  This is the most
 	  efficient option when sufficient kernel resources are available.
 
+config SPARSEMEM_CLASSIC
+	def_bool SPARSEMEM && !SPARSEMEM_VMEMMAP
+
 config VMEMMAP_OPTIMIZATION
 	bool
 	depends on SPARSEMEM_VMEMMAP
--- a/mm/util.c~mm-add-config_sparsemem_classic
+++ a/mm/util.c
@@ -1590,7 +1590,7 @@ unsigned int folio_pte_batch(struct foli
 }
 #endif /* CONFIG_MMU */
 
-#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
+#ifdef CONFIG_SPARSEMEM_CLASSIC
 /**
  * page_range_contiguous - test whether the page range is contiguous
  * @page: the start of the page range.
_

Patches currently in -mm which might be from chengkaitao@kylinos.cn are

mm-hugetlb-use-hugetlb_vmemmap_optimizable-in-boolean-contexts.patch
mm-page-flags-define-hwpoison-test-and-change-helpers-unconditionally.patch
nvdimm-pmem-remove-test_and_clear_pmem_poison.patch