[PATCH v2 0/4] mm, arch: add generic implementation of pfn_valid() for FLATMEM

[PATCH v2 0/4] mm, arch: add generic implementation of pfn_valid() for FLATMEM

[Mike Rapoport]

From: "Mike Rapoport (IBM)" <rppt@kernel.org>

Hi,

Every architecture that supports FLATMEM memory model defines its own
version of pfn_valid() that essentially compares a pfn to max_mapnr.

Use mips/powerpc version implemented as static inline as a generic
implementation of pfn_valid() and drop its per-architecture definitions

v2:
* fix build on ARM and xtensa
* add Acked- and Reviewed-by, thanks everybody

v1: https://lore.kernel.org/all/20230125190757.22555-1-rppt@kernel.org

Mike Rapoport (IBM) (4):
  arm: include asm-generic/memory_model.h from page.h rather than
    memory.h
  m68k: use asm-generic/memory_model.h for both MMU and !MMU
  mips: drop definition of pfn_valid() for DISCONTIGMEM
  mm, arch: add generic implementation of pfn_valid() for FLATMEM

 arch/alpha/include/asm/page.h      |  4 ----
 arch/arc/include/asm/page.h        |  1 -
 arch/arm/include/asm/memory.h      |  2 --
 arch/arm/include/asm/page.h        |  2 ++
 arch/csky/include/asm/page.h       |  1 -
 arch/hexagon/include/asm/page.h    |  1 -
 arch/ia64/include/asm/page.h       |  4 ----
 arch/loongarch/include/asm/page.h  | 13 -------------
 arch/m68k/include/asm/page.h       |  6 +-----
 arch/m68k/include/asm/page_mm.h    |  1 -
 arch/m68k/include/asm/page_no.h    |  4 ----
 arch/microblaze/include/asm/page.h |  1 -
 arch/mips/include/asm/page.h       | 28 ----------------------------
 arch/nios2/include/asm/page.h      |  9 ---------
 arch/openrisc/include/asm/page.h   |  2 --
 arch/parisc/include/asm/page.h     |  4 ----
 arch/powerpc/include/asm/page.h    |  9 ---------
 arch/riscv/include/asm/page.h      |  5 -----
 arch/sh/include/asm/page.h         |  3 ---
 arch/sparc/include/asm/page_32.h   |  1 -
 arch/um/include/asm/page.h         |  1 -
 arch/x86/include/asm/page_32.h     |  4 ----
 arch/x86/include/asm/page_64.h     |  4 ----
 arch/xtensa/include/asm/page.h     |  4 ++--
 include/asm-generic/memory_model.h | 12 ++++++++++++
 include/asm-generic/page.h         |  2 --
 26 files changed, 17 insertions(+), 111 deletions(-)


base-commit: 2241ab53cbb5cdb08a6b2d4688feb13971058f65
-- 
2.35.1

[PATCH v2 1/4] arm: include asm-generic/memory_model.h from page.h rather than memory.h

[Mike Rapoport]

From: "Mike Rapoport (IBM)" <rppt@kernel.org>

Makes it consistent with other architectures and allows for generic
definition of pfn_valid() in asm-generic/memory_model.h with clear override
in arch/arm/include/asm/page.h

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/arm/include/asm/memory.h | 2 --
 arch/arm/include/asm/page.h   | 2 ++
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
index d8eef4bd8c71..62e9df024445 100644
--- a/arch/arm/include/asm/memory.h
+++ b/arch/arm/include/asm/memory.h
@@ -386,6 +386,4 @@ static inline unsigned long __virt_to_idmap(unsigned long x)
 
 #endif
 
-#include <asm-generic/memory_model.h>
-
 #endif
diff --git a/arch/arm/include/asm/page.h b/arch/arm/include/asm/page.h
index 5fcc8a600e36..74bb5947b387 100644
--- a/arch/arm/include/asm/page.h
+++ b/arch/arm/include/asm/page.h
@@ -158,6 +158,7 @@ typedef struct page *pgtable_t;
 
 #ifdef CONFIG_HAVE_ARCH_PFN_VALID
 extern int pfn_valid(unsigned long);
+#define pfn_valid pfn_valid
 #endif
 
 #include <asm/memory.h>
@@ -167,5 +168,6 @@ extern int pfn_valid(unsigned long);
 #define VM_DATA_DEFAULT_FLAGS	VM_DATA_FLAGS_TSK_EXEC
 
 #include <asm-generic/getorder.h>
+#include <asm-generic/memory_model.h>
 
 #endif
-- 
2.35.1

[PATCH v2 2/4] m68k: use asm-generic/memory_model.h for both MMU and !MMU

[Mike Rapoport]

From: "Mike Rapoport (IBM)" <rppt@kernel.org>

The MMU variant uses generic definitions of page_to_pfn() and
pfn_to_page(), but !MMU defines them in include/asm/page_no.h for no
good reason.

Include asm-generic/memory_model.h in the common include/asm/page.h and
drop redundant definitions.

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
 arch/m68k/include/asm/page.h    | 6 +-----
 arch/m68k/include/asm/page_mm.h | 1 -
 arch/m68k/include/asm/page_no.h | 2 --
 3 files changed, 1 insertion(+), 8 deletions(-)

diff --git a/arch/m68k/include/asm/page.h b/arch/m68k/include/asm/page.h
index 2f1c54e4725d..a5993ad83ed8 100644
--- a/arch/m68k/include/asm/page.h
+++ b/arch/m68k/include/asm/page.h
@@ -62,11 +62,7 @@ extern unsigned long _ramend;
 #include <asm/page_no.h>
 #endif
 
-#ifndef CONFIG_MMU
-#define __phys_to_pfn(paddr)	((unsigned long)((paddr) >> PAGE_SHIFT))
-#define __pfn_to_phys(pfn)	PFN_PHYS(pfn)
-#endif
-
 #include <asm-generic/getorder.h>
+#include <asm-generic/memory_model.h>
 
 #endif /* _M68K_PAGE_H */
diff --git a/arch/m68k/include/asm/page_mm.h b/arch/m68k/include/asm/page_mm.h
index a5b459bcb7d8..3903db2e8da7 100644
--- a/arch/m68k/include/asm/page_mm.h
+++ b/arch/m68k/include/asm/page_mm.h
@@ -134,7 +134,6 @@ extern int m68k_virt_to_node_shift;
 })
 
 #define ARCH_PFN_OFFSET (m68k_memory[0].addr >> PAGE_SHIFT)
-#include <asm-generic/memory_model.h>
 
 #define virt_addr_valid(kaddr)	((unsigned long)(kaddr) >= PAGE_OFFSET && (unsigned long)(kaddr) < (unsigned long)high_memory)
 #define pfn_valid(pfn)		virt_addr_valid(pfn_to_virt(pfn))
diff --git a/arch/m68k/include/asm/page_no.h b/arch/m68k/include/asm/page_no.h
index c9d0d84158a4..0a8ccef777fd 100644
--- a/arch/m68k/include/asm/page_no.h
+++ b/arch/m68k/include/asm/page_no.h
@@ -26,8 +26,6 @@ extern unsigned long memory_end;
 #define virt_to_page(addr)	(mem_map + (((unsigned long)(addr)-PAGE_OFFSET) >> PAGE_SHIFT))
 #define page_to_virt(page)	__va(((((page) - mem_map) << PAGE_SHIFT) + PAGE_OFFSET))
 
-#define pfn_to_page(pfn)	virt_to_page(pfn_to_virt(pfn))
-#define page_to_pfn(page)	virt_to_pfn(page_to_virt(page))
 #define pfn_valid(pfn)	        ((pfn) < max_mapnr)
 
 #define	virt_addr_valid(kaddr)	(((unsigned long)(kaddr) >= PAGE_OFFSET) && \
-- 
2.35.1

[PATCH v2 3/4] mips: drop definition of pfn_valid() for DISCONTIGMEM

[Mike Rapoport]

From: "Mike Rapoport (IBM)" <rppt@kernel.org>

There is stale definition of pfn_valid() for DISCONTINGMEM memory model
guarded !FLATMEM && !SPARSEMEM && NUMA ifdefery.

Remove everything but definition of pfn_valid() for FLATMEM.

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/mips/include/asm/page.h | 15 ---------------
 1 file changed, 15 deletions(-)

diff --git a/arch/mips/include/asm/page.h b/arch/mips/include/asm/page.h
index 96bc798c1ec1..9286f11ff6ad 100644
--- a/arch/mips/include/asm/page.h
+++ b/arch/mips/include/asm/page.h
@@ -235,21 +235,6 @@ static inline int pfn_valid(unsigned long pfn)
 	return pfn >= pfn_offset && pfn < max_mapnr;
 }
 
-#elif defined(CONFIG_SPARSEMEM)
-
-/* pfn_valid is defined in linux/mmzone.h */
-
-#elif defined(CONFIG_NUMA)
-
-#define pfn_valid(pfn)							\
-({									\
-	unsigned long __pfn = (pfn);					\
-	int __n = pfn_to_nid(__pfn);					\
-	((__n >= 0) ? (__pfn < NODE_DATA(__n)->node_start_pfn +		\
-			       NODE_DATA(__n)->node_spanned_pages)	\
-		    : 0);						\
-})
-
 #endif
 
 #define virt_to_pfn(kaddr)   	PFN_DOWN(virt_to_phys((void *)(kaddr)))
-- 
2.35.1

[PATCH v2 4/4] mm, arch: add generic implementation of pfn_valid() for FLATMEM

[Mike Rapoport]

From: "Mike Rapoport (IBM)" <rppt@kernel.org>

Every architecture that supports FLATMEM memory model defines its own
version of pfn_valid() that essentially compares a pfn to max_mapnr.

Use mips/powerpc version implemented as static inline as a generic
implementation of pfn_valid() and drop its per-architecture definitions.

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Guo Ren <guoren@kernel.org>		# csky
Acked-by: Huacai Chen <chenhuacai@loongson.cn>	# LoongArch
Acked-by: Stafford Horne <shorne@gmail.com>	# OpenRISC
---
 arch/alpha/include/asm/page.h      |  4 ----
 arch/arc/include/asm/page.h        |  1 -
 arch/csky/include/asm/page.h       |  1 -
 arch/hexagon/include/asm/page.h    |  1 -
 arch/ia64/include/asm/page.h       |  4 ----
 arch/loongarch/include/asm/page.h  | 13 -------------
 arch/m68k/include/asm/page_no.h    |  2 --
 arch/microblaze/include/asm/page.h |  1 -
 arch/mips/include/asm/page.h       | 13 -------------
 arch/nios2/include/asm/page.h      |  9 ---------
 arch/openrisc/include/asm/page.h   |  2 --
 arch/parisc/include/asm/page.h     |  4 ----
 arch/powerpc/include/asm/page.h    |  9 ---------
 arch/riscv/include/asm/page.h      |  5 -----
 arch/sh/include/asm/page.h         |  3 ---
 arch/sparc/include/asm/page_32.h   |  1 -
 arch/um/include/asm/page.h         |  1 -
 arch/x86/include/asm/page_32.h     |  4 ----
 arch/x86/include/asm/page_64.h     |  4 ----
 arch/xtensa/include/asm/page.h     |  4 ++--
 include/asm-generic/memory_model.h | 12 ++++++++++++
 include/asm-generic/page.h         |  2 --
 22 files changed, 14 insertions(+), 86 deletions(-)

diff --git a/arch/alpha/include/asm/page.h b/arch/alpha/include/asm/page.h
index 8f3f5eecba28..227d32b6b75f 100644
--- a/arch/alpha/include/asm/page.h
+++ b/arch/alpha/include/asm/page.h
@@ -87,10 +87,6 @@ typedef struct page *pgtable_t;
 #define virt_to_page(kaddr)	pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
 #define virt_addr_valid(kaddr)	pfn_valid((__pa(kaddr) >> PAGE_SHIFT))
 
-#ifdef CONFIG_FLATMEM
-#define pfn_valid(pfn)		((pfn) < max_mapnr)
-#endif /* CONFIG_FLATMEM */
-
 #include <asm-generic/memory_model.h>
 #include <asm-generic/getorder.h>
 
diff --git a/arch/arc/include/asm/page.h b/arch/arc/include/asm/page.h
index 9a62e1d87967..e43fe27ec54d 100644
--- a/arch/arc/include/asm/page.h
+++ b/arch/arc/include/asm/page.h
@@ -109,7 +109,6 @@ extern int pfn_valid(unsigned long pfn);
 #else /* CONFIG_HIGHMEM */
 
 #define ARCH_PFN_OFFSET		virt_to_pfn(CONFIG_LINUX_RAM_BASE)
-#define pfn_valid(pfn)		(((pfn) - ARCH_PFN_OFFSET) < max_mapnr)
 
 #endif /* CONFIG_HIGHMEM */
 
diff --git a/arch/csky/include/asm/page.h b/arch/csky/include/asm/page.h
index ed7451478b1b..b23e3006a9e0 100644
--- a/arch/csky/include/asm/page.h
+++ b/arch/csky/include/asm/page.h
@@ -39,7 +39,6 @@
 
 #define virt_addr_valid(kaddr)  ((void *)(kaddr) >= (void *)PAGE_OFFSET && \
 			(void *)(kaddr) < high_memory)
-#define pfn_valid(pfn)		((pfn) >= ARCH_PFN_OFFSET && ((pfn) - ARCH_PFN_OFFSET) < max_mapnr)
 
 extern void *memset(void *dest, int c, size_t l);
 extern void *memcpy(void *to, const void *from, size_t l);
diff --git a/arch/hexagon/include/asm/page.h b/arch/hexagon/include/asm/page.h
index d7d4f9fca327..9c03b9965f07 100644
--- a/arch/hexagon/include/asm/page.h
+++ b/arch/hexagon/include/asm/page.h
@@ -95,7 +95,6 @@ struct page;
 /* Default vm area behavior is non-executable.  */
 #define VM_DATA_DEFAULT_FLAGS	VM_DATA_FLAGS_NON_EXEC
 
-#define pfn_valid(pfn) ((pfn) < max_mapnr)
 #define virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
 
 /*  Need to not use a define for linesize; may move this to another file.  */
diff --git a/arch/ia64/include/asm/page.h b/arch/ia64/include/asm/page.h
index 1b990466d540..783eceab5df3 100644
--- a/arch/ia64/include/asm/page.h
+++ b/arch/ia64/include/asm/page.h
@@ -97,10 +97,6 @@ do {						\
 
 #include <asm-generic/memory_model.h>
 
-#ifdef CONFIG_FLATMEM
-# define pfn_valid(pfn)		((pfn) < max_mapnr)
-#endif
-
 #define page_to_phys(page)	(page_to_pfn(page) << PAGE_SHIFT)
 #define virt_to_page(kaddr)	pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
 #define pfn_to_kaddr(pfn)	__va((pfn) << PAGE_SHIFT)
diff --git a/arch/loongarch/include/asm/page.h b/arch/loongarch/include/asm/page.h
index 53f284a96182..fb5338b352e6 100644
--- a/arch/loongarch/include/asm/page.h
+++ b/arch/loongarch/include/asm/page.h
@@ -82,19 +82,6 @@ typedef struct { unsigned long pgprot; } pgprot_t;
 
 #define pfn_to_kaddr(pfn)	__va((pfn) << PAGE_SHIFT)
 
-#ifdef CONFIG_FLATMEM
-
-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 < max_mapnr;
-}
-
-#endif
-
 #define virt_to_pfn(kaddr)	PFN_DOWN(PHYSADDR(kaddr))
 #define virt_to_page(kaddr)	pfn_to_page(virt_to_pfn(kaddr))
 
diff --git a/arch/m68k/include/asm/page_no.h b/arch/m68k/include/asm/page_no.h
index 0a8ccef777fd..2555ec57149d 100644
--- a/arch/m68k/include/asm/page_no.h
+++ b/arch/m68k/include/asm/page_no.h
@@ -26,8 +26,6 @@ extern unsigned long memory_end;
 #define virt_to_page(addr)	(mem_map + (((unsigned long)(addr)-PAGE_OFFSET) >> PAGE_SHIFT))
 #define page_to_virt(page)	__va(((((page) - mem_map) << PAGE_SHIFT) + PAGE_OFFSET))
 
-#define pfn_valid(pfn)	        ((pfn) < max_mapnr)
-
 #define	virt_addr_valid(kaddr)	(((unsigned long)(kaddr) >= PAGE_OFFSET) && \
 				((unsigned long)(kaddr) < memory_end))
 
diff --git a/arch/microblaze/include/asm/page.h b/arch/microblaze/include/asm/page.h
index 4b8b2fa78fc5..7b9861bcd458 100644
--- a/arch/microblaze/include/asm/page.h
+++ b/arch/microblaze/include/asm/page.h
@@ -112,7 +112,6 @@ extern int page_is_ram(unsigned long pfn);
 #  define page_to_phys(page)     (page_to_pfn(page) << PAGE_SHIFT)
 
 #  define ARCH_PFN_OFFSET	(memory_start >> PAGE_SHIFT)
-#  define pfn_valid(pfn)	((pfn) >= ARCH_PFN_OFFSET && (pfn) < (max_mapnr + ARCH_PFN_OFFSET))
 # endif /* __ASSEMBLY__ */
 
 #define	virt_addr_valid(vaddr)	(pfn_valid(virt_to_pfn(vaddr)))
diff --git a/arch/mips/include/asm/page.h b/arch/mips/include/asm/page.h
index 9286f11ff6ad..5978a8dfb917 100644
--- a/arch/mips/include/asm/page.h
+++ b/arch/mips/include/asm/page.h
@@ -224,19 +224,6 @@ extern phys_addr_t __phys_addr_symbol(unsigned long x);
 
 #define pfn_to_kaddr(pfn)	__va((pfn) << PAGE_SHIFT)
 
-#ifdef CONFIG_FLATMEM
-
-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 < max_mapnr;
-}
-
-#endif
-
 #define virt_to_pfn(kaddr)   	PFN_DOWN(virt_to_phys((void *)(kaddr)))
 #define virt_to_page(kaddr)	pfn_to_page(virt_to_pfn(kaddr))
 
diff --git a/arch/nios2/include/asm/page.h b/arch/nios2/include/asm/page.h
index 6a989819a7c1..0ae7d9ce369b 100644
--- a/arch/nios2/include/asm/page.h
+++ b/arch/nios2/include/asm/page.h
@@ -86,15 +86,6 @@ extern struct page *mem_map;
 
 # define pfn_to_kaddr(pfn)	__va((pfn) << PAGE_SHIFT)
 
-static inline bool 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 < max_mapnr;
-}
-
 # define virt_to_page(vaddr)	pfn_to_page(PFN_DOWN(virt_to_phys(vaddr)))
 # define virt_addr_valid(vaddr)	pfn_valid(PFN_DOWN(virt_to_phys(vaddr)))
 
diff --git a/arch/openrisc/include/asm/page.h b/arch/openrisc/include/asm/page.h
index aab6e64d6db4..52b0d7e76446 100644
--- a/arch/openrisc/include/asm/page.h
+++ b/arch/openrisc/include/asm/page.h
@@ -80,8 +80,6 @@ typedef struct page *pgtable_t;
 
 #define page_to_phys(page)      ((dma_addr_t)page_to_pfn(page) << PAGE_SHIFT)
 
-#define pfn_valid(pfn)          ((pfn) < max_mapnr)
-
 #define virt_addr_valid(kaddr)	(pfn_valid(virt_to_pfn(kaddr)))
 
 #endif /* __ASSEMBLY__ */
diff --git a/arch/parisc/include/asm/page.h b/arch/parisc/include/asm/page.h
index 6faaaa3ebe9b..667e703c0e8f 100644
--- a/arch/parisc/include/asm/page.h
+++ b/arch/parisc/include/asm/page.h
@@ -155,10 +155,6 @@ extern int npmem_ranges;
 #define __pa(x)			((unsigned long)(x)-PAGE_OFFSET)
 #define __va(x)			((void *)((unsigned long)(x)+PAGE_OFFSET))
 
-#ifndef CONFIG_SPARSEMEM
-#define pfn_valid(pfn)		((pfn) < max_mapnr)
-#endif
-
 #ifdef CONFIG_HUGETLB_PAGE
 #define HPAGE_SHIFT		PMD_SHIFT /* fixed for transparent huge pages */
 #define HPAGE_SIZE      	((1UL) << HPAGE_SHIFT)
diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
index edf1dd1b0ca9..f2b6bf5687d0 100644
--- a/arch/powerpc/include/asm/page.h
+++ b/arch/powerpc/include/asm/page.h
@@ -117,15 +117,6 @@ extern long long virt_phys_offset;
 
 #ifdef CONFIG_FLATMEM
 #define ARCH_PFN_OFFSET		((unsigned long)(MEMORY_START >> PAGE_SHIFT))
-#ifndef __ASSEMBLY__
-extern unsigned long max_mapnr;
-static inline bool pfn_valid(unsigned long pfn)
-{
-	unsigned long min_pfn = ARCH_PFN_OFFSET;
-
-	return pfn >= min_pfn && pfn < max_mapnr;
-}
-#endif
 #endif
 
 #define virt_to_pfn(kaddr)	(__pa(kaddr) >> PAGE_SHIFT)
diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h
index 9f432c1b5289..7fed7c431928 100644
--- a/arch/riscv/include/asm/page.h
+++ b/arch/riscv/include/asm/page.h
@@ -171,11 +171,6 @@ extern phys_addr_t __phys_addr_symbol(unsigned long x);
 
 #define sym_to_pfn(x)           __phys_to_pfn(__pa_symbol(x))
 
-#ifdef CONFIG_FLATMEM
-#define pfn_valid(pfn) \
-	(((pfn) >= ARCH_PFN_OFFSET) && (((pfn) - ARCH_PFN_OFFSET) < max_mapnr))
-#endif
-
 #endif /* __ASSEMBLY__ */
 
 #define virt_addr_valid(vaddr)	({						\
diff --git a/arch/sh/include/asm/page.h b/arch/sh/include/asm/page.h
index eca5daa43b93..09ac6c7faee0 100644
--- a/arch/sh/include/asm/page.h
+++ b/arch/sh/include/asm/page.h
@@ -169,9 +169,6 @@ typedef struct page *pgtable_t;
 #define PFN_START		(__MEMORY_START >> PAGE_SHIFT)
 #define ARCH_PFN_OFFSET		(PFN_START)
 #define virt_to_page(kaddr)	pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
-#ifdef CONFIG_FLATMEM
-#define pfn_valid(pfn)		((pfn) >= min_low_pfn && (pfn) < max_low_pfn)
-#endif
 #define virt_addr_valid(kaddr)	pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
 
 #include <asm-generic/memory_model.h>
diff --git a/arch/sparc/include/asm/page_32.h b/arch/sparc/include/asm/page_32.h
index fff8861df107..6be6f683f98f 100644
--- a/arch/sparc/include/asm/page_32.h
+++ b/arch/sparc/include/asm/page_32.h
@@ -130,7 +130,6 @@ extern unsigned long pfn_base;
 #define ARCH_PFN_OFFSET		(pfn_base)
 #define virt_to_page(kaddr)	pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
 
-#define pfn_valid(pfn)		(((pfn) >= (pfn_base)) && (((pfn)-(pfn_base)) < max_mapnr))
 #define virt_addr_valid(kaddr)	((((unsigned long)(kaddr)-PAGE_OFFSET)>>PAGE_SHIFT) < max_mapnr)
 
 #include <asm-generic/memory_model.h>
diff --git a/arch/um/include/asm/page.h b/arch/um/include/asm/page.h
index cdbd9653aa14..84866127d074 100644
--- a/arch/um/include/asm/page.h
+++ b/arch/um/include/asm/page.h
@@ -108,7 +108,6 @@ extern unsigned long uml_physmem;
 #define phys_to_pfn(p) ((p) >> PAGE_SHIFT)
 #define pfn_to_phys(pfn) PFN_PHYS(pfn)
 
-#define pfn_valid(pfn) ((pfn) < max_mapnr)
 #define virt_addr_valid(v) pfn_valid(phys_to_pfn(__pa(v)))
 
 #include <asm-generic/memory_model.h>
diff --git a/arch/x86/include/asm/page_32.h b/arch/x86/include/asm/page_32.h
index df42f8aa99e4..580d71aca65a 100644
--- a/arch/x86/include/asm/page_32.h
+++ b/arch/x86/include/asm/page_32.h
@@ -15,10 +15,6 @@ extern unsigned long __phys_addr(unsigned long);
 #define __phys_addr_symbol(x)	__phys_addr(x)
 #define __phys_reloc_hide(x)	RELOC_HIDE((x), 0)
 
-#ifdef CONFIG_FLATMEM
-#define pfn_valid(pfn)		((pfn) < max_mapnr)
-#endif /* CONFIG_FLATMEM */
-
 #include <linux/string.h>
 
 static inline void clear_page(void *page)
diff --git a/arch/x86/include/asm/page_64.h b/arch/x86/include/asm/page_64.h
index 198e03e59ca1..cc6b8e087192 100644
--- a/arch/x86/include/asm/page_64.h
+++ b/arch/x86/include/asm/page_64.h
@@ -39,10 +39,6 @@ extern unsigned long __phys_addr_symbol(unsigned long);
 
 #define __phys_reloc_hide(x)	(x)
 
-#ifdef CONFIG_FLATMEM
-#define pfn_valid(pfn)          ((pfn) < max_pfn)
-#endif
-
 void clear_page_orig(void *page);
 void clear_page_rep(void *page);
 void clear_page_erms(void *page);
diff --git a/arch/xtensa/include/asm/page.h b/arch/xtensa/include/asm/page.h
index 493eb7083b1a..a77d04972eb9 100644
--- a/arch/xtensa/include/asm/page.h
+++ b/arch/xtensa/include/asm/page.h
@@ -11,6 +11,8 @@
 #ifndef _XTENSA_PAGE_H
 #define _XTENSA_PAGE_H
 
+#include <linux/const.h>
+
 #include <asm/processor.h>
 #include <asm/types.h>
 #include <asm/cache.h>
@@ -189,8 +191,6 @@ static inline unsigned long ___pa(unsigned long va)
 #endif
 #define __va(x)	\
 	((void *)((unsigned long) (x) - PHYS_OFFSET + PAGE_OFFSET))
-#define pfn_valid(pfn) \
-	((pfn) >= ARCH_PFN_OFFSET && ((pfn) - ARCH_PFN_OFFSET) < max_mapnr)
 
 #define virt_to_page(kaddr)	pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
 #define page_to_virt(page)	__va(page_to_pfn(page) << PAGE_SHIFT)
diff --git a/include/asm-generic/memory_model.h b/include/asm-generic/memory_model.h
index a2c8ed60233a..13d2a844d928 100644
--- a/include/asm-generic/memory_model.h
+++ b/include/asm-generic/memory_model.h
@@ -19,6 +19,18 @@
 #define __page_to_pfn(page)	((unsigned long)((page) - mem_map) + \
 				 ARCH_PFN_OFFSET)
 
+#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 < max_mapnr;
+}
+#define pfn_valid pfn_valid
+#endif
+
 #elif defined(CONFIG_SPARSEMEM_VMEMMAP)
 
 /* memmap is virtually contiguous.  */
diff --git a/include/asm-generic/page.h b/include/asm-generic/page.h
index 6fc47561814c..c0be2edeb484 100644
--- a/include/asm-generic/page.h
+++ b/include/asm-generic/page.h
@@ -84,8 +84,6 @@ extern unsigned long memory_end;
 #define page_to_phys(page)      ((dma_addr_t)page_to_pfn(page) << PAGE_SHIFT)
 #endif
 
-#define pfn_valid(pfn)		((pfn) >= ARCH_PFN_OFFSET && ((pfn) - ARCH_PFN_OFFSET) < max_mapnr)
-
 #define	virt_addr_valid(kaddr)	(((void *)(kaddr) >= (void *)PAGE_OFFSET) && \
 				((void *)(kaddr) < (void *)memory_end))
 
-- 
2.35.1