memblock: move reserve_bootmem_range() to memblock.c and make it static

reserve_bootmem_region() is only called from
memmap_init_reserved_pages() and it was in mm/mm_init.c because of its
dependecies on static init_deferred_page().

Since init_deferred_page() is not static anymore, move
reserve_bootmem_region(), rename it to memmap_init_reserved_range() and
make it static.

Update the comment describing it to better reflect what the function
does and drop bogus comment about reserved pages in free_bootmem_page().

Update memblock test stubs to reflect the core changes.

Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Reviewed-by: David Hildenbrand (Arm) <david@kernel.org>
Link: https://patch.msgid.link/20260323072042.3651061-1-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

Author: rppt

include/linux/bootmem_info.h

@@ -44,10 +44,6 @@ static inline void free_bootmem_page(struct page *page)
 {
 	enum bootmem_type type = bootmem_type(page);
 
-	/*
-	 * The reserve_bootmem_region sets the reserved flag on bootmem
-	 * pages.
-	 */
 	VM_BUG_ON_PAGE(page_ref_count(page) != 2, page);
 
 	if (type == SECTION_INFO || type == MIX_SECTION_INFO)

include/linux/mm.h

@@ -3686,9 +3686,6 @@ extern unsigned long free_reserved_area(void *start, void *end,
 
 extern void adjust_managed_page_count(struct page *page, long count);
 
-extern void reserve_bootmem_region(phys_addr_t start,
-				   phys_addr_t end, int nid);
-
 /* Free the reserved page into the buddy system, so it gets managed. */
 void free_reserved_page(struct page *page);
 

mm/memblock.c

@@ -974,7 +974,7 @@ __init void memmap_init_kho_scratch_pages(void)
 	/*
 	 * Initialize struct pages for free scratch memory.
 	 * The struct pages for reserved scratch memory will be set up in
-	 * reserve_bootmem_region()
+	 * memmap_init_reserved_pages()
 	 */
 	__for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE,
 			     MEMBLOCK_KHO_SCRATCH, &start, &end, &nid) {
@@ -2241,6 +2241,31 @@ static unsigned long __init __free_memory_core(phys_addr_t start,
 	return end_pfn - start_pfn;
 }
 
+/*
+ * Initialised pages do not have PageReserved set. This function is called
+ * for each reserved range and marks the pages PageReserved.
+ * When deferred initialization of struct pages is enabled it also ensures
+ * that struct pages are properly initialised.
+ */
+static void __init memmap_init_reserved_range(phys_addr_t start,
+					      phys_addr_t end, int nid)
+{
+	unsigned long pfn;
+
+	for_each_valid_pfn(pfn, PFN_DOWN(start), PFN_UP(end)) {
+		struct page *page = pfn_to_page(pfn);
+
+		init_deferred_page(pfn, nid);
+
+		/*
+		 * no need for atomic set_bit because the struct
+		 * page is not visible yet so nobody should
+		 * access it yet.
+		 */
+		__SetPageReserved(page);
+	}
+}
+
 static void __init memmap_init_reserved_pages(void)
 {
 	struct memblock_region *region;
@@ -2260,7 +2285,7 @@ static void __init memmap_init_reserved_pages(void)
 		end = start + region->size;
 
 		if (memblock_is_nomap(region))
-			reserve_bootmem_region(start, end, nid);
+			memmap_init_reserved_range(start, end, nid);
 
 		memblock_set_node(start, region->size, &memblock.reserved, nid);
 	}
@@ -2285,7 +2310,7 @@ static void __init memmap_init_reserved_pages(void)
 			if (!numa_valid_node(nid))
 				nid = early_pfn_to_nid(PFN_DOWN(start));
 
-			reserve_bootmem_region(start, end, nid);
+			memmap_init_reserved_range(start, end, nid);
 		}
 	}
 }

mm/mm_init.c

@@ -772,31 +772,6 @@ void __meminit init_deferred_page(unsigned long pfn, int nid)
 	__init_deferred_page(pfn, nid);
 }
 
-/*
- * Initialised pages do not have PageReserved set. This function is
- * called for each range allocated by the bootmem allocator and
- * marks the pages PageReserved. The remaining valid pages are later
- * sent to the buddy page allocator.
- */
-void __meminit reserve_bootmem_region(phys_addr_t start,
-				      phys_addr_t end, int nid)
-{
-	unsigned long pfn;
-
-	for_each_valid_pfn(pfn, PFN_DOWN(start), PFN_UP(end)) {
-		struct page *page = pfn_to_page(pfn);
-
-		__init_deferred_page(pfn, nid);
-
-		/*
-		 * no need for atomic set_bit because the struct
-		 * page is not visible yet so nobody should
-		 * access it yet.
-		 */
-		__SetPageReserved(page);
-	}
-}
-
 /* If zone is ZONE_MOVABLE but memory is mirrored, it is an overlapped init */
 static bool __meminit
 overlap_memmap_init(unsigned long zone, unsigned long *pfn)

tools/include/linux/mm.h

@@ -32,8 +32,6 @@ static inline phys_addr_t virt_to_phys(volatile void *address)
 	return (phys_addr_t)address;
 }
 
-void reserve_bootmem_region(phys_addr_t start, phys_addr_t end, int nid);
-
 static inline void totalram_pages_inc(void)
 {
 }

tools/testing/memblock/internal.h

@@ -29,4 +29,13 @@ static inline unsigned long free_reserved_area(void *start, void *end,
 	return 0;
 }
 
+#define for_each_valid_pfn(pfn, start_pfn, end_pfn)                     \
+       for ((pfn) = (start_pfn); (pfn) < (end_pfn); (pfn)++)
+
+static inline void init_deferred_page(unsigned long pfn, int nid)
+{
+}
+
+#define __SetPageReserved(p)	((void)(p))
+
 #endif

tools/testing/memblock/mmzone.c

@@ -11,10 +11,6 @@ struct pglist_data *next_online_pgdat(struct pglist_data *pgdat)
 	return NULL;
 }
 
-void reserve_bootmem_region(phys_addr_t start, phys_addr_t end, int nid)
-{
-}
-
 void atomic_long_set(atomic_long_t *v, long i)
 {
 }