diff --git a/arch/alpha/mm/init.c b/arch/alpha/mm/init.c
index 61c2198b1359..ec0eeae9c653 100644
--- a/arch/alpha/mm/init.c
+++ b/arch/alpha/mm/init.c
@@ -276,7 +276,6 @@ srm_paging_stop (void)
 void __init
 mem_init(void)
 {
-	set_max_mapnr(max_low_pfn);
 	high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
 	memblock_free_all();
 }
diff --git a/arch/arc/mm/init.c b/arch/arc/mm/init.c
index 6a71b23f1383..7ef883d58dc1 100644
--- a/arch/arc/mm/init.c
+++ b/arch/arc/mm/init.c
@@ -154,11 +154,6 @@ void __init setup_arch_memory(void)
 
 	arch_pfn_offset = min(min_low_pfn, min_high_pfn);
 	kmap_init();
-
-#else /* CONFIG_HIGHMEM */
-	/* pfn_valid() uses this when FLATMEM=y and HIGHMEM=n */
-	max_mapnr = max_low_pfn - min_low_pfn;
-
 #endif /* CONFIG_HIGHMEM */
 
 	free_area_init(max_zone_pfn);
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 9aec1cb2386f..d4bcc745a044 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -275,8 +275,6 @@ void __init mem_init(void)
 	swiotlb_init(max_pfn > arm_dma_pfn_limit, SWIOTLB_VERBOSE);
 #endif
 
-	set_max_mapnr(pfn_to_page(max_pfn) - mem_map);
-
 #ifdef CONFIG_SA1111
 	/* now that our DMA memory is actually so designated, we can free it */
 	memblock_phys_free(PHYS_OFFSET, __pa(swapper_pg_dir) - PHYS_OFFSET);
diff --git a/arch/csky/mm/init.c b/arch/csky/mm/init.c
index ab51acbc19b2..ba6694d6170a 100644
--- a/arch/csky/mm/init.c
+++ b/arch/csky/mm/init.c
@@ -46,10 +46,6 @@ void __init mem_init(void)
 {
 #ifdef CONFIG_HIGHMEM
 	unsigned long tmp;
-
-	set_max_mapnr(highend_pfn - ARCH_PFN_OFFSET);
-#else
-	set_max_mapnr(max_low_pfn - ARCH_PFN_OFFSET);
 #endif
 	high_memory = (void *) __va(max_low_pfn << PAGE_SHIFT);
 
diff --git a/arch/loongarch/mm/init.c b/arch/loongarch/mm/init.c
index ca5aa5f46a9f..00449df50db1 100644
--- a/arch/loongarch/mm/init.c
+++ b/arch/loongarch/mm/init.c
@@ -78,7 +78,6 @@ void __init paging_init(void)
 
 void __init mem_init(void)
 {
-	max_mapnr = max_low_pfn;
 	high_memory = (void *) __va(max_low_pfn << PAGE_SHIFT);
 
 	memblock_free_all();
diff --git a/arch/microblaze/mm/init.c b/arch/microblaze/mm/init.c
index 4520c5741579..857cd2b44bcf 100644
--- a/arch/microblaze/mm/init.c
+++ b/arch/microblaze/mm/init.c
@@ -104,17 +104,13 @@ void __init setup_memory(void)
 	 *
 	 * min_low_pfn - the first page (mm/bootmem.c - node_boot_start)
 	 * max_low_pfn
-	 * max_mapnr - the first unused page (mm/bootmem.c - node_low_pfn)
 	 */
 
 	/* memory start is from the kernel end (aligned) to higher addr */
 	min_low_pfn = memory_start >> PAGE_SHIFT; /* minimum for allocation */
-	/* RAM is assumed contiguous */
-	max_mapnr = memory_size >> PAGE_SHIFT;
 	max_low_pfn = ((u64)memory_start + (u64)lowmem_size) >> PAGE_SHIFT;
 	max_pfn = ((u64)memory_start + (u64)memory_size) >> PAGE_SHIFT;
 
-	pr_info("%s: max_mapnr: %#lx\n", __func__, max_mapnr);
 	pr_info("%s: min_low_pfn: %#lx\n", __func__, min_low_pfn);
 	pr_info("%s: max_low_pfn: %#lx\n", __func__, max_low_pfn);
 	pr_info("%s: max_pfn: %#lx\n", __func__, max_pfn);
diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
index f51cd97376df..338b3c9fc5bc 100644
--- a/arch/mips/mm/init.c
+++ b/arch/mips/mm/init.c
@@ -417,15 +417,7 @@ void __init paging_init(void)
 		       " %ldk highmem ignored\n",
 		       (highend_pfn - max_low_pfn) << (PAGE_SHIFT - 10));
 		max_zone_pfns[ZONE_HIGHMEM] = max_low_pfn;
-
-		max_mapnr = max_low_pfn;
-	} else if (highend_pfn) {
-		max_mapnr = highend_pfn;
-	} else {
-		max_mapnr = max_low_pfn;
 	}
-#else
-	max_mapnr = max_low_pfn;
 #endif
 	high_memory = (void *) __va(max_low_pfn << PAGE_SHIFT);
 
diff --git a/arch/nios2/kernel/setup.c b/arch/nios2/kernel/setup.c
index a4cffbfc1399..2a40150142c3 100644
--- a/arch/nios2/kernel/setup.c
+++ b/arch/nios2/kernel/setup.c
@@ -158,7 +158,6 @@ void __init setup_arch(char **cmdline_p)
 	*cmdline_p = boot_command_line;
 
 	find_limits(&min_low_pfn, &max_low_pfn, &max_pfn);
-	max_mapnr = max_low_pfn;
 
 	memblock_reserve(__pa_symbol(_stext), _end - _stext);
 #ifdef CONFIG_BLK_DEV_INITRD
diff --git a/arch/nios2/mm/init.c b/arch/nios2/mm/init.c
index aa692ad30044..3cafa87ead9e 100644
--- a/arch/nios2/mm/init.c
+++ b/arch/nios2/mm/init.c
@@ -51,7 +51,7 @@ void __init paging_init(void)
 	pagetable_init();
 	pgd_current = swapper_pg_dir;
 
-	max_zone_pfn[ZONE_NORMAL] = max_mapnr;
+	max_zone_pfn[ZONE_NORMAL] = max_low_pfn;
 
 	/* pass the memory from the bootmem allocator to the main allocator */
 	free_area_init(max_zone_pfn);
diff --git a/arch/openrisc/mm/init.c b/arch/openrisc/mm/init.c
index d0cb1a0126f9..9093c336e158 100644
--- a/arch/openrisc/mm/init.c
+++ b/arch/openrisc/mm/init.c
@@ -193,7 +193,6 @@ void __init mem_init(void)
 {
 	BUG_ON(!mem_map);
 
-	max_mapnr = max_low_pfn;
 	high_memory = (void *)__va(max_low_pfn * PAGE_SIZE);
 
 	/* clear the zero-page */
diff --git a/arch/parisc/mm/init.c b/arch/parisc/mm/init.c
index 61c0a2477072..2cdfc0b1195c 100644
--- a/arch/parisc/mm/init.c
+++ b/arch/parisc/mm/init.c
@@ -563,7 +563,6 @@ void __init mem_init(void)
 #endif
 
 	high_memory = __va((max_pfn << PAGE_SHIFT));
-	set_max_mapnr(max_low_pfn);
 	memblock_free_all();
 
 #ifdef CONFIG_PA11
diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index a08b0ede4e64..68d47c53876c 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -957,8 +957,6 @@ void __init setup_arch(char **cmdline_p)
 
 	/* Parse memory topology */
 	mem_topology_setup();
-	/* Set max_mapnr before paging_init() */
-	set_max_mapnr(max_pfn);
 	high_memory = (void *)__va(max_low_pfn * PAGE_SIZE);
 
 	/*
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 15b2eda4c364..157c9ca51541 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -298,7 +298,6 @@ static void __init setup_bootmem(void)
 	high_memory = (void *)(__va(PFN_PHYS(max_low_pfn)));
 
 	dma32_phys_limit = min(4UL * SZ_1G, (unsigned long)PFN_PHYS(max_low_pfn));
-	set_max_mapnr(max_low_pfn - ARCH_PFN_OFFSET);
 
 	reserve_initrd_mem();
 
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 020aa2f78d01..7e64243693c9 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -161,7 +161,6 @@ void __init mem_init(void)
 	cpumask_set_cpu(0, &init_mm.context.cpu_attach_mask);
 	cpumask_set_cpu(0, mm_cpumask(&init_mm));
 
-	set_max_mapnr(max_low_pfn);
         high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
 
 	pv_init();
diff --git a/arch/sh/mm/init.c b/arch/sh/mm/init.c
index 289a2fecebef..72aea5cd1b85 100644
--- a/arch/sh/mm/init.c
+++ b/arch/sh/mm/init.c
@@ -290,7 +290,6 @@ void __init paging_init(void)
 	 */
 	max_low_pfn = max_pfn = memblock_end_of_DRAM() >> PAGE_SHIFT;
 	min_low_pfn = __MEMORY_START >> PAGE_SHIFT;
-	set_max_mapnr(max_low_pfn - min_low_pfn);
 
 	nodes_clear(node_online_map);
 
diff --git a/arch/sparc/mm/init_32.c b/arch/sparc/mm/init_32.c
index d96a14ffceeb..6b58da14edc6 100644
--- a/arch/sparc/mm/init_32.c
+++ b/arch/sparc/mm/init_32.c
@@ -275,7 +275,6 @@ void __init mem_init(void)
 
 	taint_real_pages();
 
-	max_mapnr = last_valid_pfn - pfn_base;
 	high_memory = __va(max_low_pfn << PAGE_SHIFT);
 	memblock_free_all();
 
diff --git a/arch/um/include/shared/mem_user.h b/arch/um/include/shared/mem_user.h
index adfa08062f88..d4727efcf23d 100644
--- a/arch/um/include/shared/mem_user.h
+++ b/arch/um/include/shared/mem_user.h
@@ -47,7 +47,6 @@ extern int iomem_size;
 #define ROUND_4M(n) ((((unsigned long) (n)) + (1 << 22)) & ~((1 << 22) - 1))
 
 extern unsigned long find_iomem(char *driver, unsigned long *len_out);
-extern void mem_total_pages(unsigned long physmem, unsigned long iomem);
 extern void setup_physmem(unsigned long start, unsigned long usable,
 			  unsigned long len);
 extern void map_memory(unsigned long virt, unsigned long phys,
diff --git a/arch/um/kernel/physmem.c b/arch/um/kernel/physmem.c
index a74f17b033c4..af02b5f9911d 100644
--- a/arch/um/kernel/physmem.c
+++ b/arch/um/kernel/physmem.c
@@ -22,18 +22,6 @@ static int physmem_fd = -1;
 unsigned long high_physmem;
 EXPORT_SYMBOL(high_physmem);
 
-void __init mem_total_pages(unsigned long physmem, unsigned long iomem)
-{
-	unsigned long phys_pages, iomem_pages, total_pages;
-
-	phys_pages  = physmem >> PAGE_SHIFT;
-	iomem_pages = iomem   >> PAGE_SHIFT;
-
-	total_pages = phys_pages + iomem_pages;
-
-	max_mapnr = total_pages;
-}
-
 void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
 		int r, int w, int x)
 {
diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index 79ea97d4797e..6414cbf00572 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -419,7 +419,6 @@ void __init setup_arch(char **cmdline_p)
 
 	stack_protections((unsigned long) init_task.stack);
 	setup_physmem(uml_physmem, uml_reserved, physmem_size);
-	mem_total_pages(physmem_size, iomem_size);
 	uml_dtb_init();
 	read_initrd();
 
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index ac41b1e0940d..6d2f8cb9451e 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -650,9 +650,6 @@ void __init initmem_init(void)
 
 	memblock_set_node(0, PHYS_ADDR_MAX, &memblock.memory, 0);
 
-#ifdef CONFIG_FLATMEM
-	max_mapnr = IS_ENABLED(CONFIG_HIGHMEM) ? highend_pfn : max_low_pfn;
-#endif
 	__vmalloc_start_set = true;
 
 	printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
diff --git a/arch/xtensa/mm/init.c b/arch/xtensa/mm/init.c
index 01577d33e602..9f1b0d5fccc7 100644
--- a/arch/xtensa/mm/init.c
+++ b/arch/xtensa/mm/init.c
@@ -164,7 +164,6 @@ void __init mem_init(void)
 {
 	free_highpages();
 
-	max_mapnr = max_pfn - ARCH_PFN_OFFSET;
 	high_memory = (void *)__va(max_low_pfn << PAGE_SHIFT);
 
 	memblock_free_all();
diff --git a/include/asm-generic/memory_model.h b/include/asm-generic/memory_model.h
index 6d1fb6162ac1..a3b5029aebbd 100644
--- a/include/asm-generic/memory_model.h
+++ b/include/asm-generic/memory_model.h
@@ -19,11 +19,12 @@
 #define __page_to_pfn(page)	((unsigned long)((page) - mem_map) + \
 				 ARCH_PFN_OFFSET)
 
+/* avoid <linux/mm.h> include hell */
+extern unsigned long max_mapnr;
+
 #ifndef pfn_valid
 static inline int pfn_valid(unsigned long pfn)
 {
-	/* avoid <linux/mm.h> include hell */
-	extern unsigned long max_mapnr;
 	unsigned long pfn_offset = ARCH_PFN_OFFSET;
 
 	return pfn >= pfn_offset && (pfn - pfn_offset) < max_mapnr;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 7b1068ddcbb7..fdf20503850e 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -45,17 +45,6 @@ extern int sysctl_page_lock_unfairness;
 void mm_core_init(void);
 void init_mm_internals(void);
 
-#ifndef CONFIG_NUMA		/* Don't use mapnrs, do it properly */
-extern unsigned long max_mapnr;
-
-static inline void set_max_mapnr(unsigned long limit)
-{
-	max_mapnr = limit;
-}
-#else
-static inline void set_max_mapnr(unsigned long limit) { }
-#endif
-
 extern atomic_long_t _totalram_pages;
 static inline unsigned long totalram_pages(void)
 {
diff --git a/mm/memory.c b/mm/memory.c
index b4d3d4893267..126fdd3001e3 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -95,14 +95,6 @@
 #warning Unfortunate NUMA and NUMA Balancing config, growing page-frame for last_cpupid.
 #endif
 
-#ifndef CONFIG_NUMA
-unsigned long max_mapnr;
-EXPORT_SYMBOL(max_mapnr);
-
-struct page *mem_map;
-EXPORT_SYMBOL(mem_map);
-#endif
-
 static vm_fault_t do_fault(struct vm_fault *vmf);
 static vm_fault_t do_anonymous_page(struct vm_fault *vmf);
 static bool vmf_pte_changed(struct vm_fault *vmf);
diff --git a/mm/mm_init.c b/mm/mm_init.c
index 2630cc30147e..50a93714e1c6 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -36,6 +36,14 @@
 
 #include <asm/setup.h>
 
+#ifndef CONFIG_NUMA
+unsigned long max_mapnr;
+EXPORT_SYMBOL(max_mapnr);
+
+struct page *mem_map;
+EXPORT_SYMBOL(mem_map);
+#endif
+
 #ifdef CONFIG_DEBUG_MEMORY_INIT
 int __meminitdata mminit_loglevel;
 
@@ -1617,7 +1625,7 @@ static void __init alloc_node_mem_map(struct pglist_data *pgdat)
 	start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
 	offset = pgdat->node_start_pfn - start;
 	/*
-		 * The zone's endpoints aren't required to be MAX_PAGE_ORDER
+	 * The zone's endpoints aren't required to be MAX_PAGE_ORDER
 	 * aligned but the node_mem_map endpoints must be in order
 	 * for the buddy allocator to function correctly.
 	 */
@@ -1633,14 +1641,15 @@ static void __init alloc_node_mem_map(struct pglist_data *pgdat)
 	pr_debug("%s: node %d, pgdat %08lx, node_mem_map %08lx\n",
 		 __func__, pgdat->node_id, (unsigned long)pgdat,
 		 (unsigned long)pgdat->node_mem_map);
-#ifndef CONFIG_NUMA
+
 	/* the global mem_map is just set as node 0's */
-	if (pgdat == NODE_DATA(0)) {
-		mem_map = NODE_DATA(0)->node_mem_map;
-		if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
-			mem_map -= offset;
-	}
-#endif
+	WARN_ON(pgdat != NODE_DATA(0));
+
+	mem_map = pgdat->node_mem_map;
+	if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
+		mem_map -= offset;
+
+	max_mapnr = end - start;
 }
 #else
 static inline void alloc_node_mem_map(struct pglist_data *pgdat) { }
diff --git a/mm/nommu.c b/mm/nommu.c
index baa79abdaf03..f0209dd26dfa 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -44,16 +44,12 @@
 
 void *high_memory;
 EXPORT_SYMBOL(high_memory);
-struct page *mem_map;
-unsigned long max_mapnr;
-EXPORT_SYMBOL(max_mapnr);
 unsigned long highest_memmap_pfn;
 int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS;
 int heap_stack_gap = 0;
 
 atomic_long_t mmap_pages_allocated;
 
-EXPORT_SYMBOL(mem_map);
 
 /* list of mapped, potentially shareable regions */
 static struct kmem_cache *vm_region_jar;
