[PATCH 0/3] move __HAVE_ARCH_PTE_SPECIAL in Kconfig

[PATCH 0/3] move __HAVE_ARCH_PTE_SPECIAL in Kconfig

[Laurent Dufour]

The per architecture __HAVE_ARCH_PTE_SPECIAL is defined statically in the
per architecture header files. This doesn't allow to make other
configuration dependent on it.

This series is moving the __HAVE_ARCH_PTE_SPECIAL into the Kconfig files,
setting it automatically when architectures was already setting it in
header file.

There is no functional change introduced by this series.

Laurent Dufour (3):
  mm: introduce ARCH_HAS_PTE_SPECIAL
  mm: replace __HAVE_ARCH_PTE_SPECIAL
  mm: remove __HAVE_ARCH_PTE_SPECIAL

 Documentation/features/vm/pte_special/arch-support.txt | 2 +-
 arch/arc/Kconfig                                       | 1 +
 arch/arc/include/asm/pgtable.h                         | 2 --
 arch/arm/Kconfig                                       | 1 +
 arch/arm/include/asm/pgtable-3level.h                  | 1 -
 arch/arm64/Kconfig                                     | 1 +
 arch/arm64/include/asm/pgtable.h                       | 2 --
 arch/powerpc/Kconfig                                   | 1 +
 arch/powerpc/include/asm/book3s/64/pgtable.h           | 3 ---
 arch/powerpc/include/asm/pte-common.h                  | 3 ---
 arch/riscv/Kconfig                                     | 1 +
 arch/s390/Kconfig                                      | 1 +
 arch/s390/include/asm/pgtable.h                        | 1 -
 arch/sh/Kconfig                                        | 1 +
 arch/sh/include/asm/pgtable.h                          | 2 --
 arch/sparc/Kconfig                                     | 1 +
 arch/sparc/include/asm/pgtable_64.h                    | 3 ---
 arch/x86/Kconfig                                       | 1 +
 arch/x86/include/asm/pgtable_types.h                   | 1 -
 include/linux/pfn_t.h                                  | 4 ++--
 mm/Kconfig                                             | 3 +++
 mm/gup.c                                               | 4 ++--
 mm/memory.c                                            | 2 +-
 23 files changed, 18 insertions(+), 24 deletions(-)

-- 
2.7.4

[PATCH 1/3] mm: introduce ARCH_HAS_PTE_SPECIAL

[Laurent Dufour]

Currently the PTE special supports is turned on in per architecture header
files. Most of the time, it is defined in arch/*/include/asm/pgtable.h
depending or not on some other per architecture static definition.

This patch introduce a new configuration variable to manage this directly
in the Kconfig files. It would later replace __HAVE_ARCH_PTE_SPECIAL.

Here notes for some architecture where the definition of
__HAVE_ARCH_PTE_SPECIAL is not obvious:

arm
 __HAVE_ARCH_PTE_SPECIAL which is currently defined in
arch/arm/include/asm/pgtable-3level.h which is included by
arch/arm/include/asm/pgtable.h when CONFIG_ARM_LPAE is set.
So select ARCH_HAS_PTE_SPECIAL if ARM_LPAE.

powerpc
__HAVE_ARCH_PTE_SPECIAL is defined in 2 files:
 - arch/powerpc/include/asm/book3s/64/pgtable.h
 - arch/powerpc/include/asm/pte-common.h
The first one is included if (PPC_BOOK3S & PPC64) while the second is
included in all the other cases.
So select ARCH_HAS_PTE_SPECIAL all the time.

sparc:
__HAVE_ARCH_PTE_SPECIAL is defined if defined(__sparc__) &&
defined(__arch64__) which are defined through the compiler in
sparc/Makefile if !SPARC32 which I assume to be if SPARC64.
So select ARCH_HAS_PTE_SPECIAL if SPARC64

Suggested-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
---
 arch/arc/Kconfig     | 1 +
 arch/arm/Kconfig     | 1 +
 arch/arm64/Kconfig   | 1 +
 arch/powerpc/Kconfig | 1 +
 arch/riscv/Kconfig   | 1 +
 arch/s390/Kconfig    | 1 +
 arch/sh/Kconfig      | 1 +
 arch/sparc/Kconfig   | 1 +
 arch/x86/Kconfig     | 1 +
 mm/Kconfig           | 3 +++
 10 files changed, 12 insertions(+)

diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index d76bf4a83740..8516e2b0239a 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -44,6 +44,7 @@ config ARC
 	select HAVE_GENERIC_DMA_COHERENT
 	select HAVE_KERNEL_GZIP
 	select HAVE_KERNEL_LZMA
+	select ARCH_HAS_PTE_SPECIAL
 
 config MIGHT_HAVE_PCI
 	bool
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 1878083771af..a67973cb041c 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -7,6 +7,7 @@ config ARM
 	select ARCH_HAS_DEBUG_VIRTUAL if MMU
 	select ARCH_HAS_DEVMEM_IS_ALLOWED
 	select ARCH_HAS_ELF_RANDOMIZE
+	select ARCH_HAS_PTE_SPECIAL if ARM_LPAE
 	select ARCH_HAS_SET_MEMORY
 	select ARCH_HAS_PHYS_TO_DMA
 	select ARCH_HAS_STRICT_KERNEL_RWX if MMU && !XIP_KERNEL
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 276e96ceaf27..7ae3c09921fb 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -17,6 +17,7 @@ config ARM64
 	select ARCH_HAS_GIGANTIC_PAGE if (MEMORY_ISOLATION && COMPACTION) || CMA
 	select ARCH_HAS_KCOV
 	select ARCH_HAS_MEMBARRIER_SYNC_CORE
+	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_SET_MEMORY
 	select ARCH_HAS_SG_CHAIN
 	select ARCH_HAS_STRICT_KERNEL_RWX
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index c32a181a7cbb..f7415fe25c07 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -141,6 +141,7 @@ config PPC
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select ARCH_HAS_PHYS_TO_DMA
 	select ARCH_HAS_PMEM_API                if PPC64
+	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_MEMBARRIER_CALLBACKS
 	select ARCH_HAS_SCALED_CPUTIME		if VIRT_CPU_ACCOUNTING_NATIVE
 	select ARCH_HAS_SG_CHAIN
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 148865de1692..b0a8404bf684 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -34,6 +34,7 @@ config RISCV
 	select THREAD_INFO_IN_TASK
 	select RISCV_TIMER
 	select GENERIC_IRQ_MULTI_HANDLER
+	select ARCH_HAS_PTE_SPECIAL
 
 config MMU
 	def_bool y
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 32a0d5b958bf..5f1f4997e7e9 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -72,6 +72,7 @@ config S390
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select ARCH_HAS_GIGANTIC_PAGE if (MEMORY_ISOLATION && COMPACTION) || CMA
 	select ARCH_HAS_KCOV
+	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_SET_MEMORY
 	select ARCH_HAS_SG_CHAIN
 	select ARCH_HAS_STRICT_KERNEL_RWX
diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index 97fe29316476..a6c75b6806d2 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -50,6 +50,7 @@ config SUPERH
 	select HAVE_ARCH_AUDITSYSCALL
 	select HAVE_FUTEX_CMPXCHG if FUTEX
 	select HAVE_NMI
+	select ARCH_HAS_PTE_SPECIAL
 	help
 	  The SuperH is a RISC processor targeted for use in embedded systems
 	  and consumer electronics; it was also used in the Sega Dreamcast
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 8767e45f1b2b..6b5a4f05dcb2 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -86,6 +86,7 @@ config SPARC64
 	select ARCH_USE_QUEUED_SPINLOCKS
 	select GENERIC_TIME_VSYSCALL
 	select ARCH_CLOCKSOURCE_DATA
+	select ARCH_HAS_PTE_SPECIAL
 
 config ARCH_DEFCONFIG
 	string
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index bf4ddea48e61..3f5fb25486bf 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -56,6 +56,7 @@ config X86
 	select ARCH_HAS_KCOV			if X86_64
 	select ARCH_HAS_MEMBARRIER_SYNC_CORE
 	select ARCH_HAS_PMEM_API		if X86_64
+	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_REFCOUNT
 	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
 	select ARCH_HAS_SET_MEMORY
diff --git a/mm/Kconfig b/mm/Kconfig
index bf9d6366bced..60ae67b83e62 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -757,3 +757,6 @@ config GUP_BENCHMARK
 	  performance of get_user_pages_fast().
 
 	  See tools/testing/selftests/vm/gup_benchmark.c
+
+config ARCH_HAS_PTE_SPECIAL
+	bool
-- 
2.7.4

[PATCH 2/3] mm: replace __HAVE_ARCH_PTE_SPECIAL

[Laurent Dufour]

Replace __HAVE_ARCH_PTE_SPECIAL by the new configuration variable
CONFIG_ARCH_HAS_PTE_SPECIAL.

Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
---
 Documentation/features/vm/pte_special/arch-support.txt | 2 +-
 include/linux/pfn_t.h                                  | 4 ++--
 mm/gup.c                                               | 4 ++--
 mm/memory.c                                            | 2 +-
 4 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/Documentation/features/vm/pte_special/arch-support.txt b/Documentation/features/vm/pte_special/arch-support.txt
index 055004f467d2..cd05924ea875 100644
--- a/Documentation/features/vm/pte_special/arch-support.txt
+++ b/Documentation/features/vm/pte_special/arch-support.txt
@@ -1,6 +1,6 @@
 #
 # Feature name:          pte_special
-#         Kconfig:       __HAVE_ARCH_PTE_SPECIAL
+#         Kconfig:       ARCH_HAS_PTE_SPECIAL
 #         description:   arch supports the pte_special()/pte_mkspecial() VM APIs
 #
     -----------------------
diff --git a/include/linux/pfn_t.h b/include/linux/pfn_t.h
index a03c2642a87c..21713dc14ce2 100644
--- a/include/linux/pfn_t.h
+++ b/include/linux/pfn_t.h
@@ -122,7 +122,7 @@ pud_t pud_mkdevmap(pud_t pud);
 #endif
 #endif /* __HAVE_ARCH_PTE_DEVMAP */
 
-#ifdef __HAVE_ARCH_PTE_SPECIAL
+#ifdef CONFIG_ARCH_HAS_PTE_SPECIAL
 static inline bool pfn_t_special(pfn_t pfn)
 {
 	return (pfn.val & PFN_SPECIAL) == PFN_SPECIAL;
@@ -132,5 +132,5 @@ static inline bool pfn_t_special(pfn_t pfn)
 {
 	return false;
 }
-#endif /* __HAVE_ARCH_PTE_SPECIAL */
+#endif /* CONFIG_ARCH_HAS_PTE_SPECIAL */
 #endif /* _LINUX_PFN_T_H_ */
diff --git a/mm/gup.c b/mm/gup.c
index 2e2df7f3e92d..9e6a4f70deab 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1354,7 +1354,7 @@ static void undo_dev_pagemap(int *nr, int nr_start, struct page **pages)
 	}
 }
 
-#ifdef __HAVE_ARCH_PTE_SPECIAL
+#ifdef CONFIG_ARCH_HAS_PTE_SPECIAL
 static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,
 			 int write, struct page **pages, int *nr)
 {
@@ -1430,7 +1430,7 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,
 {
 	return 0;
 }
-#endif /* __HAVE_ARCH_PTE_SPECIAL */
+#endif /* CONFIG_ARCH_HAS_PTE_SPECIAL */
 
 #if defined(__HAVE_ARCH_PTE_DEVMAP) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
 static int __gup_device_huge(unsigned long pfn, unsigned long addr,
diff --git a/mm/memory.c b/mm/memory.c
index 1bb725631ded..6fc7b9edc18f 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -817,7 +817,7 @@ static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
  * PFNMAP mappings in order to support COWable mappings.
  *
  */
-#ifdef __HAVE_ARCH_PTE_SPECIAL
+#ifdef CONFIG_ARCH_HAS_PTE_SPECIAL
 # define HAVE_PTE_SPECIAL 1
 #else
 # define HAVE_PTE_SPECIAL 0
-- 
2.7.4

[PATCH 3/3] mm: remove __HAVE_ARCH_PTE_SPECIAL

[Laurent Dufour]

It is now replaced by Kconfig variable CONFIG_ARCH_HAS_PTE_SPECIAL.

Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
---
 arch/arc/include/asm/pgtable.h               | 2 --
 arch/arm/include/asm/pgtable-3level.h        | 1 -
 arch/arm64/include/asm/pgtable.h             | 2 --
 arch/powerpc/include/asm/book3s/64/pgtable.h | 3 ---
 arch/powerpc/include/asm/pte-common.h        | 3 ---
 arch/s390/include/asm/pgtable.h              | 1 -
 arch/sh/include/asm/pgtable.h                | 2 --
 arch/sparc/include/asm/pgtable_64.h          | 3 ---
 arch/x86/include/asm/pgtable_types.h         | 1 -
 9 files changed, 18 deletions(-)

diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h
index 08fe33830d4b..8ec5599a0957 100644
--- a/arch/arc/include/asm/pgtable.h
+++ b/arch/arc/include/asm/pgtable.h
@@ -320,8 +320,6 @@ PTE_BIT_FUNC(mkexec,	|= (_PAGE_EXECUTE));
 PTE_BIT_FUNC(mkspecial,	|= (_PAGE_SPECIAL));
 PTE_BIT_FUNC(mkhuge,	|= (_PAGE_HW_SZ));
 
-#define __HAVE_ARCH_PTE_SPECIAL
-
 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 {
 	return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot));
diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h
index 2a4836087358..6d50a11d7793 100644
--- a/arch/arm/include/asm/pgtable-3level.h
+++ b/arch/arm/include/asm/pgtable-3level.h
@@ -219,7 +219,6 @@ static inline pte_t pte_mkspecial(pte_t pte)
 	pte_val(pte) |= L_PTE_SPECIAL;
 	return pte;
 }
-#define	__HAVE_ARCH_PTE_SPECIAL
 
 #define pmd_write(pmd)		(pmd_isclear((pmd), L_PMD_SECT_RDONLY))
 #define pmd_dirty(pmd)		(pmd_isset((pmd), L_PMD_SECT_DIRTY))
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 7e2c27e63cd8..b96c8a186908 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -306,8 +306,6 @@ static inline int pte_same(pte_t pte_a, pte_t pte_b)
 #define HPAGE_MASK		(~(HPAGE_SIZE - 1))
 #define HUGETLB_PAGE_ORDER	(HPAGE_SHIFT - PAGE_SHIFT)
 
-#define __HAVE_ARCH_PTE_SPECIAL
-
 static inline pte_t pgd_pte(pgd_t pgd)
 {
 	return __pte(pgd_val(pgd));
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index a6b9f1d74600..f12d148eccbe 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -338,9 +338,6 @@ extern unsigned long pci_io_base;
 /* Advertise special mapping type for AGP */
 #define HAVE_PAGE_AGP
 
-/* Advertise support for _PAGE_SPECIAL */
-#define __HAVE_ARCH_PTE_SPECIAL
-
 #ifndef __ASSEMBLY__
 
 /*
diff --git a/arch/powerpc/include/asm/pte-common.h b/arch/powerpc/include/asm/pte-common.h
index c4a72c7a8c83..03dfddb1f49a 100644
--- a/arch/powerpc/include/asm/pte-common.h
+++ b/arch/powerpc/include/asm/pte-common.h
@@ -216,9 +216,6 @@ static inline bool pte_user(pte_t pte)
 #define PAGE_AGP		(PAGE_KERNEL_NC)
 #define HAVE_PAGE_AGP
 
-/* Advertise support for _PAGE_SPECIAL */
-#define __HAVE_ARCH_PTE_SPECIAL
-
 #ifndef _PAGE_READ
 /* if not defined, we should not find _PAGE_WRITE too */
 #define _PAGE_READ 0
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 2d24d33bf188..9809694e1389 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -171,7 +171,6 @@ static inline int is_module_addr(void *addr)
 #define _PAGE_WRITE	0x020		/* SW pte write bit */
 #define _PAGE_SPECIAL	0x040		/* SW associated with special page */
 #define _PAGE_UNUSED	0x080		/* SW bit for pgste usage state */
-#define __HAVE_ARCH_PTE_SPECIAL
 
 #ifdef CONFIG_MEM_SOFT_DIRTY
 #define _PAGE_SOFT_DIRTY 0x002		/* SW pte soft dirty bit */
diff --git a/arch/sh/include/asm/pgtable.h b/arch/sh/include/asm/pgtable.h
index 89c513a982fc..f6abfe2bca93 100644
--- a/arch/sh/include/asm/pgtable.h
+++ b/arch/sh/include/asm/pgtable.h
@@ -156,8 +156,6 @@ extern void page_table_range_init(unsigned long start, unsigned long end,
 #define HAVE_ARCH_UNMAPPED_AREA
 #define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
 
-#define __HAVE_ARCH_PTE_SPECIAL
-
 #include <asm-generic/pgtable.h>
 
 #endif /* __ASM_SH_PGTABLE_H */
diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
index 44d6ac47e035..1393a8ac596b 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -117,9 +117,6 @@ bool kern_addr_valid(unsigned long addr);
 #define _PAGE_PMD_HUGE    _AC(0x0100000000000000,UL) /* Huge page            */
 #define _PAGE_PUD_HUGE    _PAGE_PMD_HUGE
 
-/* Advertise support for _PAGE_SPECIAL */
-#define __HAVE_ARCH_PTE_SPECIAL
-
 /* SUN4U pte bits... */
 #define _PAGE_SZ4MB_4U	  _AC(0x6000000000000000,UL) /* 4MB Page             */
 #define _PAGE_SZ512K_4U	  _AC(0x4000000000000000,UL) /* 512K Page            */
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index acfe755562a6..3e195728d7d1 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -65,7 +65,6 @@
 #define _PAGE_PKEY_BIT2	(_AT(pteval_t, 0))
 #define _PAGE_PKEY_BIT3	(_AT(pteval_t, 0))
 #endif
-#define __HAVE_ARCH_PTE_SPECIAL
 
 #define _PAGE_PKEY_MASK (_PAGE_PKEY_BIT0 | \
 			 _PAGE_PKEY_BIT1 | \
-- 
2.7.4

[PATCH 0/3] move __HAVE_ARCH_PTE_SPECIAL in Kconfig

[Michal Hocko]

On Mon 09-04-18 15:57:06, Laurent Dufour wrote:
> The per architecture __HAVE_ARCH_PTE_SPECIAL is defined statically in the
> per architecture header files. This doesn't allow to make other
> configuration dependent on it.
> 
> This series is moving the __HAVE_ARCH_PTE_SPECIAL into the Kconfig files,
> setting it automatically when architectures was already setting it in
> header file.
> 
> There is no functional change introduced by this series.

I would just fold all three patches into a single one. It is much easier
to review that those selects are done properly when you can see that the
define is set for the same architecture.

In general, I like the patch. It is always quite painful to track per
arch defines.

> Laurent Dufour (3):
>   mm: introduce ARCH_HAS_PTE_SPECIAL
>   mm: replace __HAVE_ARCH_PTE_SPECIAL
>   mm: remove __HAVE_ARCH_PTE_SPECIAL
> 
>  Documentation/features/vm/pte_special/arch-support.txt | 2 +-
>  arch/arc/Kconfig                                       | 1 +
>  arch/arc/include/asm/pgtable.h                         | 2 --
>  arch/arm/Kconfig                                       | 1 +
>  arch/arm/include/asm/pgtable-3level.h                  | 1 -
>  arch/arm64/Kconfig                                     | 1 +
>  arch/arm64/include/asm/pgtable.h                       | 2 --
>  arch/powerpc/Kconfig                                   | 1 +
>  arch/powerpc/include/asm/book3s/64/pgtable.h           | 3 ---
>  arch/powerpc/include/asm/pte-common.h                  | 3 ---
>  arch/riscv/Kconfig                                     | 1 +
>  arch/s390/Kconfig                                      | 1 +
>  arch/s390/include/asm/pgtable.h                        | 1 -
>  arch/sh/Kconfig                                        | 1 +
>  arch/sh/include/asm/pgtable.h                          | 2 --
>  arch/sparc/Kconfig                                     | 1 +
>  arch/sparc/include/asm/pgtable_64.h                    | 3 ---
>  arch/x86/Kconfig                                       | 1 +
>  arch/x86/include/asm/pgtable_types.h                   | 1 -
>  include/linux/pfn_t.h                                  | 4 ++--
>  mm/Kconfig                                             | 3 +++
>  mm/gup.c                                               | 4 ++--
>  mm/memory.c                                            | 2 +-
>  23 files changed, 18 insertions(+), 24 deletions(-)
> 
> -- 
> 2.7.4

-- 
Michal Hocko
SUSE Labs

[PATCH 0/3] move __HAVE_ARCH_PTE_SPECIAL in Kconfig

[Jerome Glisse]

On Mon, Apr 09, 2018 at 04:07:21PM +0200, Michal Hocko wrote:
> On Mon 09-04-18 15:57:06, Laurent Dufour wrote:
> > The per architecture __HAVE_ARCH_PTE_SPECIAL is defined statically in the
> > per architecture header files. This doesn't allow to make other
> > configuration dependent on it.
> > 
> > This series is moving the __HAVE_ARCH_PTE_SPECIAL into the Kconfig files,
> > setting it automatically when architectures was already setting it in
> > header file.
> > 
> > There is no functional change introduced by this series.
> 
> I would just fold all three patches into a single one. It is much easier
> to review that those selects are done properly when you can see that the
> define is set for the same architecture.
> 
> In general, I like the patch. It is always quite painful to track per
> arch defines.

You can also add Reviewed-by: J?r?me Glisse <jglisse@redhat> my grep fu
showed no place that was forgotten.

Cheers,
J?r?me

[PATCH 0/3] move __HAVE_ARCH_PTE_SPECIAL in Kconfig

[Vineet Gupta]

On 04/09/2018 06:57 AM, Laurent Dufour wrote:
> The per architecture __HAVE_ARCH_PTE_SPECIAL is defined statically in the
> per architecture header files. This doesn't allow to make other
> configuration dependent on it.

So I understand this series has more "readability" value and I'm fine with this 
change but I wonder if you really would want to make something depend on it or 
make this de-configurable. PTE special is really a fundamental construct - e.g. it 
is used for anon mapped pages where zero page has been wired up etc...

-Vineet

> This series is moving the __HAVE_ARCH_PTE_SPECIAL into the Kconfig files,
> setting it automatically when architectures was already setting it in
> header file.
>
> There is no functional change introduced by this series.

[PATCH 0/3] move __HAVE_ARCH_PTE_SPECIAL in Kconfig

[Laurent Dufour]

On 09/04/2018 18:03, Vineet Gupta wrote:
> On 04/09/2018 06:57 AM, Laurent Dufour wrote:
>> The per architecture __HAVE_ARCH_PTE_SPECIAL is defined statically in the
>> per architecture header files. This doesn't allow to make other
>> configuration dependent on it.
> 
> So I understand this series has more "readability" value and I'm fine with this
> change but I wonder if you really would want to make something depend on it or
> make this de-configurable. PTE special is really a fundamental construct - e.g.
> it is used for anon mapped pages where zero page has been wired up etc...

I don't want it to be de-configurable. This is almost like
ARCH_SUPPORTS_MEMORY_FAILURE, ARCH_USES_HIGH_VMA_FLAGS, ARCH_HAS_HMM...

These values are selected by per architecture Kconfig files and are not exposed
through the configuration menu.

Concerning making something depend on it, I will probably make
CONFIG_SPECULATIVE_PAGE_FAULT introduced by the SPF series dependent on it.
For details, please see https://lkml.org/lkml/2018/3/13/1143

Thanks,
Laurent.

[PATCH 2/3] mm: replace __HAVE_ARCH_PTE_SPECIAL

[Christoph Hellwig]

> -#ifdef __HAVE_ARCH_PTE_SPECIAL
> +#ifdef CONFIG_ARCH_HAS_PTE_SPECIAL
>  # define HAVE_PTE_SPECIAL 1
>  #else
>  # define HAVE_PTE_SPECIAL 0

I'd say kill this odd indirection and just use the
CONFIG_ARCH_HAS_PTE_SPECIAL symbol directly.

[PATCH 2/3] mm: replace __HAVE_ARCH_PTE_SPECIAL

[David Rientjes]

On Mon, 9 Apr 2018, Christoph Hellwig wrote:

> > -#ifdef __HAVE_ARCH_PTE_SPECIAL
> > +#ifdef CONFIG_ARCH_HAS_PTE_SPECIAL
> >  # define HAVE_PTE_SPECIAL 1
> >  #else
> >  # define HAVE_PTE_SPECIAL 0
> 
> I'd say kill this odd indirection and just use the
> CONFIG_ARCH_HAS_PTE_SPECIAL symbol directly.
> 
> 

Agree, and I think it would be easier to audit/review if patches 1 and 3 
were folded together to see the relationship between the newly added 
selects and what #define's it is replacing.  Otherwise, looks good!

[PATCH 2/3] mm: replace __HAVE_ARCH_PTE_SPECIAL

[Laurent Dufour]

On 09/04/2018 22:08, David Rientjes wrote:
> On Mon, 9 Apr 2018, Christoph Hellwig wrote:
> 
>>> -#ifdef __HAVE_ARCH_PTE_SPECIAL
>>> +#ifdef CONFIG_ARCH_HAS_PTE_SPECIAL
>>>  # define HAVE_PTE_SPECIAL 1
>>>  #else
>>>  # define HAVE_PTE_SPECIAL 0
>>
>> I'd say kill this odd indirection and just use the
>> CONFIG_ARCH_HAS_PTE_SPECIAL symbol directly.
>>
>>
> 
> Agree, and I think it would be easier to audit/review if patches 1 and 3 
> were folded together to see the relationship between the newly added 
> selects and what #define's it is replacing.  Otherwise, looks good!
>

Ok I will fold the 3 patches and introduce a new one removing HAVE_PTE_SPECIAL.

Thanks,
Laurent.