[merged mm-stable] mm-sparse-keep-mem_section_usage_size-internal.patch removed from -mm tree

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

The quilt patch titled
     Subject: mm/sparse: keep mem_section_usage_size() internal
has been removed from the -mm tree.  Its filename was
     mm-sparse-keep-mem_section_usage_size-internal.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Muchun Song <songmuchun@bytedance.com>
Subject: mm/sparse: keep mem_section_usage_size() internal
Date: Wed, 5 Aug 2026 10:25:36 +0800

mem_section_usage_size() is only needed by sparsemem implementation code
after commit ae751d567baa ("mm/bootmem_info: stop marking
mem_section_usage as MIX_SECTION_INFO"), so keeping the declaration in
mmzone.h now exposes the helper to all mmzone.h users for no reason.

Move the helper to sparse.h so sparse.c and sparse-vmemmap.c can share it
through the internal header.  While doing so, calculate the allocation
size with struct_size_t(), which ties the expression to the
pageblock_flags trailing array instead of open-coding the struct header
plus bitmap size.

Link: https://lore.kernel.org/20260805022536.1206575-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/mmzone.h |    1 -
 mm/sparse.c            |   10 ----------
 mm/sparse.h            |    6 ++++++
 3 files changed, 6 insertions(+), 11 deletions(-)

--- a/include/linux/mmzone.h~mm-sparse-keep-mem_section_usage_size-internal
+++ a/include/linux/mmzone.h
@@ -2069,7 +2069,6 @@ static inline struct mem_section *__nr_t
 #endif
 	return &mem_section[root][nr & SECTION_ROOT_MASK];
 }
-extern size_t mem_section_usage_size(void);
 
 /*
  * We use the lower bits of the mem_map pointer to store a little bit of
--- a/mm/sparse.c~mm-sparse-keep-mem_section_usage_size-internal
+++ a/mm/sparse.c
@@ -213,16 +213,6 @@ static void __init memblocks_present(voi
 		memory_present(nid, start, end);
 }
 
-static unsigned long usemap_size(void)
-{
-	return BITS_TO_LONGS(SECTION_BLOCKFLAGS_BITS) * sizeof(unsigned long);
-}
-
-size_t mem_section_usage_size(void)
-{
-	return sizeof(struct mem_section_usage) + usemap_size();
-}
-
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 unsigned long __init section_map_size(void)
 {
--- a/mm/sparse.h~mm-sparse-keep-mem_section_usage_size-internal
+++ a/mm/sparse.h
@@ -47,6 +47,12 @@ static inline void __section_mark_presen
 
 	ms->section_mem_map |= SECTION_MARKED_PRESENT;
 }
+
+static inline size_t mem_section_usage_size(void)
+{
+	return struct_size_t(struct mem_section_usage, pageblock_flags,
+			     BITS_TO_LONGS(SECTION_BLOCKFLAGS_BITS));
+}
 #else
 static inline void sparse_init(void) {}
 #endif /* CONFIG_SPARSEMEM */
_

Patches currently in -mm which might be from songmuchun@bytedance.com are