mm: split out sparse declarations from internal.h

mm/internal.h becomes more and more bloated.

Move declarations related to SPARSE and SPARSE_VMEMMAP memory models to
a new mm/sparse.h header.

No functional changes.

Link: https://lore.kernel.org/20260709-internal-h-v2-2-695631425968@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Muchun Song <muchun.song@linux.dev>
Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Lorenzo Stoakes <ljs@kernel.org>
Acked-by: Pratyush Yadav <pratyush@kernel.org>
Acked-by: SJ Park <sj@kernel.org>
Cc: Alexander Graf <graf@amazon.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Brendan Jackman <brendan.jackman@linux.dev>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Marco Elver <elver@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

6 files changed, 67 insertions, 52 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index 3be6db146cb9..16babc72f7c1 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17001,6 +17001,7 @@ F:	mm/pgtable-generic.c
 F:	mm/ptdump.c
 F:	mm/sparse-vmemmap.c
 F:	mm/sparse.c
+F:	mm/sparse.h
 F:	mm/util.c
 F:	mm/vmpressure.c
 F:	mm/vmstat.c
diff --git a/mm/internal.h b/mm/internal.h
index 59adb140fc7a..a29a7dab2e6c 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -807,58 +807,6 @@ static inline void init_compound_tail(struct page *tail,
 	prep_compound_tail(tail, head, order);
 }
 
-/*
- * mm/sparse.c
- */
-#ifdef CONFIG_SPARSEMEM
-void sparse_init(void);
-int sparse_index_init(unsigned long section_nr, int nid);
-
-static inline void sparse_init_one_section(struct mem_section *ms,
-		unsigned long pnum, struct page *mem_map,
-		struct mem_section_usage *usage, unsigned long flags)
-{
-	unsigned long coded_mem_map;
-
-	BUILD_BUG_ON(SECTION_MAP_LAST_BIT > PFN_SECTION_SHIFT);
-
-	/*
-	 * We encode the start PFN of the section into the mem_map such that
-	 * page_to_pfn() on !CONFIG_SPARSEMEM_VMEMMAP can simply subtract it
-	 * from the page pointer to obtain the PFN.
-	 */
-	coded_mem_map = (unsigned long)(mem_map - section_nr_to_pfn(pnum));
-	VM_WARN_ON_ONCE(coded_mem_map & ~SECTION_MAP_MASK);
-
-	ms->section_mem_map &= ~SECTION_MAP_MASK;
-	ms->section_mem_map |= coded_mem_map;
-	ms->section_mem_map |= flags | SECTION_HAS_MEM_MAP;
-	ms->usage = usage;
-}
-
-static inline void __section_mark_present(struct mem_section *ms,
-		unsigned long section_nr)
-{
-	if (section_nr > __highest_present_section_nr)
-		__highest_present_section_nr = section_nr;
-
-	ms->section_mem_map |= SECTION_MARKED_PRESENT;
-}
-#else
-static inline void sparse_init(void) {}
-#endif /* CONFIG_SPARSEMEM */
-
-/*
- * mm/sparse-vmemmap.c
- */
-#ifdef CONFIG_SPARSEMEM_VMEMMAP
-void sparse_init_subsection_map(void);
-#else
-static inline void sparse_init_subsection_map(void)
-{
-}
-#endif /* CONFIG_SPARSEMEM_VMEMMAP */
-
 #if defined CONFIG_COMPACTION || defined CONFIG_CMA
 
 /*
diff --git a/mm/mm_init.c b/mm/mm_init.c
index 39583c028e34..b557e5fe35f3 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -35,6 +35,7 @@
 #include "internal.h"
 #include "mm_init.h"
 #include "page_alloc.h"
+#include "sparse.h"
 #include "slab.h"
 #include "shuffle.h"
 
diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
index 49571676b860..5a2469fb1838 100644
--- a/mm/sparse-vmemmap.c
+++ b/mm/sparse-vmemmap.c
@@ -42,6 +42,7 @@
 
 #include "internal.h"
 #include "mm_init.h"
+#include "sparse.h"
 
 /*
  * Allocate a block of memory to be used to back the virtual memory map
diff --git a/mm/sparse.c b/mm/sparse.c
index d54e30f58b93..704a9dec2b9a 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -16,6 +16,7 @@
 #include <linux/vmstat.h>
 #include "internal.h"
 #include "mm_init.h"
+#include "sparse.h"
 #include <asm/dma.h>
 
 /*
diff --git a/mm/sparse.h b/mm/sparse.h
new file mode 100644
index 000000000000..95aa031213f2
--- /dev/null
+++ b/mm/sparse.h
@@ -0,0 +1,63 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * sparse.h:
+ *
+ * mm/ internal sparse and sparse-vmemmap declarations
+ */
+
+#ifndef __MM_SPARSE_H
+#define __MM_SPARSE_H
+
+#include <linux/mmzone.h>
+
+/*
+ * mm/sparse.c
+ */
+#ifdef CONFIG_SPARSEMEM
+void sparse_init(void);
+int sparse_index_init(unsigned long section_nr, int nid);
+
+static inline void sparse_init_one_section(struct mem_section *ms,
+		unsigned long pnum, struct page *mem_map,
+		struct mem_section_usage *usage, unsigned long flags)
+{
+	unsigned long coded_mem_map;
+
+	BUILD_BUG_ON(SECTION_MAP_LAST_BIT > PFN_SECTION_SHIFT);
+
+	/*
+	 * We encode the start PFN of the section into the mem_map such that
+	 * page_to_pfn() on !CONFIG_SPARSEMEM_VMEMMAP can simply subtract it
+	 * from the page pointer to obtain the PFN.
+	 */
+	coded_mem_map = (unsigned long)(mem_map - section_nr_to_pfn(pnum));
+	VM_WARN_ON_ONCE(coded_mem_map & ~SECTION_MAP_MASK);
+
+	ms->section_mem_map &= ~SECTION_MAP_MASK;
+	ms->section_mem_map |= coded_mem_map;
+	ms->section_mem_map |= flags | SECTION_HAS_MEM_MAP;
+	ms->usage = usage;
+}
+
+static inline void __section_mark_present(struct mem_section *ms,
+		unsigned long section_nr)
+{
+	if (section_nr > __highest_present_section_nr)
+		__highest_present_section_nr = section_nr;
+
+	ms->section_mem_map |= SECTION_MARKED_PRESENT;
+}
+#else
+static inline void sparse_init(void) {}
+#endif /* CONFIG_SPARSEMEM */
+
+/*
+ * mm/sparse-vmemmap.c
+ */
+#ifdef CONFIG_SPARSEMEM_VMEMMAP
+void sparse_init_subsection_map(void);
+#else
+static inline void sparse_init_subsection_map(void) {}
+#endif /* CONFIG_SPARSEMEM_VMEMMAP */
+
+#endif /* __MM_SPARSE_H */