[PATCH v2 0/3] Device-memory-related cleanups

[PATCH v2 0/3] Device-memory-related cleanups

[Robin Murphy]

Hi all,

This is essentially just a repost, with the trivial typo fix plus all
the acks/reviews collected. There's no direct dependency between the
patches here, so hopefully at least #1 and #3 might sneak into 5.2 if
there's still time, as that would save some bother for follow-up arm64
work next cycle which will depend on both.

Robin.


Robin Murphy (3):
  mm/memremap: Rename and consolidate SECTION_SIZE
  mm: clean up is_device_*_page() definitions
  mm: introduce ARCH_HAS_PTE_DEVMAP

 arch/powerpc/Kconfig                         |  2 +-
 arch/powerpc/include/asm/book3s/64/pgtable.h |  1 -
 arch/x86/Kconfig                             |  2 +-
 arch/x86/include/asm/pgtable.h               |  4 +-
 arch/x86/include/asm/pgtable_types.h         |  1 -
 include/linux/mm.h                           | 47 +++++++-------------
 include/linux/mmzone.h                       |  1 +
 include/linux/pfn_t.h                        |  4 +-
 kernel/memremap.c                            | 10 ++---
 mm/Kconfig                                   |  5 +--
 mm/gup.c                                     |  2 +-
 mm/hmm.c                                     |  2 -
 12 files changed, 29 insertions(+), 52 deletions(-)

-- 
2.21.0.dirty

[PATCH v2 1/3] mm/memremap: Rename and consolidate SECTION_SIZE

[Robin Murphy]

Trying to activate ZONE_DEVICE for arm64 reveals that memremap's
internal helpers for sparsemem sections conflict with and arm64's
definitions for hugepages, which inherit the name of "sections" from
earlier versions of the ARM architecture.

Disambiguate memremap (and now HMM too) by propagating sparsemem's PA_
prefix, to clarify that these values are in terms of addresses rather
than PFNs (and because it's a heck of a lot easier than changing all the
arch code). SECTION_MASK is unused, so it can just go.

[anshuman: Consolidated mm/hmm.c instance and updated the commit message]

Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---

v2: Fix commit message typo, add review tags.

 include/linux/mmzone.h |  1 +
 kernel/memremap.c      | 10 ++++------
 mm/hmm.c               |  2 --
 3 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index fba7741533be..ed7dd27ee94a 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -1081,6 +1081,7 @@ static inline unsigned long early_pfn_to_nid(unsigned long pfn)
  * PFN_SECTION_SHIFT		pfn to/from section number
  */
 #define PA_SECTION_SHIFT	(SECTION_SIZE_BITS)
+#define PA_SECTION_SIZE		(1UL << PA_SECTION_SHIFT)
 #define PFN_SECTION_SHIFT	(SECTION_SIZE_BITS - PAGE_SHIFT)
 
 #define NR_MEM_SECTIONS		(1UL << SECTIONS_SHIFT)
diff --git a/kernel/memremap.c b/kernel/memremap.c
index a856cb5ff192..dda1367b385d 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -14,8 +14,6 @@
 #include <linux/hmm.h>
 
 static DEFINE_XARRAY(pgmap_array);
-#define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1)
-#define SECTION_SIZE (1UL << PA_SECTION_SHIFT)
 
 #if IS_ENABLED(CONFIG_DEVICE_PRIVATE)
 vm_fault_t device_private_entry_fault(struct vm_area_struct *vma,
@@ -98,8 +96,8 @@ static void devm_memremap_pages_release(void *data)
 		put_page(pfn_to_page(pfn));
 
 	/* pages are dead and unused, undo the arch mapping */
-	align_start = res->start & ~(SECTION_SIZE - 1);
-	align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE)
+	align_start = res->start & ~(PA_SECTION_SIZE - 1);
+	align_size = ALIGN(res->start + resource_size(res), PA_SECTION_SIZE)
 		- align_start;
 
 	nid = page_to_nid(pfn_to_page(align_start >> PAGE_SHIFT));
@@ -154,8 +152,8 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
 	if (!pgmap->ref || !pgmap->kill)
 		return ERR_PTR(-EINVAL);
 
-	align_start = res->start & ~(SECTION_SIZE - 1);
-	align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE)
+	align_start = res->start & ~(PA_SECTION_SIZE - 1);
+	align_size = ALIGN(res->start + resource_size(res), PA_SECTION_SIZE)
 		- align_start;
 	align_end = align_start + align_size - 1;
 
diff --git a/mm/hmm.c b/mm/hmm.c
index fe1cd87e49ac..ef9e4e6c9f92 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -33,8 +33,6 @@
 #include <linux/mmu_notifier.h>
 #include <linux/memory_hotplug.h>
 
-#define PA_SECTION_SIZE (1UL << PA_SECTION_SHIFT)
-
 #if IS_ENABLED(CONFIG_HMM_MIRROR)
 static const struct mmu_notifier_ops hmm_mmu_notifier_ops;
 
-- 
2.21.0.dirty

[PATCH v2 2/3] mm: clean up is_device_*_page() definitions

[Robin Murphy]

Refactor is_device_{public,private}_page() with is_pci_p2pdma_page()
to make them all consistent in depending on their respective config
options even when CONFIG_DEV_PAGEMAP_OPS is enabled for other reasons.
This allows a little more compile-time optimisation as well as the
conceptual and cosmetic cleanup.

Suggested-by: Jerome Glisse <jglisse@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---

v2: Add review tags.

 include/linux/mm.h | 43 +++++++++++++------------------------------
 1 file changed, 13 insertions(+), 30 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 76769749b5a5..d76dfb7ac617 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -910,32 +910,6 @@ static inline bool put_devmap_managed_page(struct page *page)
 	}
 	return false;
 }
-
-static inline bool is_device_private_page(const struct page *page)
-{
-	return is_zone_device_page(page) &&
-		page->pgmap->type == MEMORY_DEVICE_PRIVATE;
-}
-
-static inline bool is_device_public_page(const struct page *page)
-{
-	return is_zone_device_page(page) &&
-		page->pgmap->type == MEMORY_DEVICE_PUBLIC;
-}
-
-#ifdef CONFIG_PCI_P2PDMA
-static inline bool is_pci_p2pdma_page(const struct page *page)
-{
-	return is_zone_device_page(page) &&
-		page->pgmap->type == MEMORY_DEVICE_PCI_P2PDMA;
-}
-#else /* CONFIG_PCI_P2PDMA */
-static inline bool is_pci_p2pdma_page(const struct page *page)
-{
-	return false;
-}
-#endif /* CONFIG_PCI_P2PDMA */
-
 #else /* CONFIG_DEV_PAGEMAP_OPS */
 static inline void dev_pagemap_get_ops(void)
 {
@@ -949,22 +923,31 @@ static inline bool put_devmap_managed_page(struct page *page)
 {
 	return false;
 }
+#endif /* CONFIG_DEV_PAGEMAP_OPS */
 
 static inline bool is_device_private_page(const struct page *page)
 {
-	return false;
+	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
+		IS_ENABLED(CONFIG_DEVICE_PRIVATE) &&
+		is_zone_device_page(page) &&
+		page->pgmap->type == MEMORY_DEVICE_PRIVATE;
 }
 
 static inline bool is_device_public_page(const struct page *page)
 {
-	return false;
+	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
+		IS_ENABLED(CONFIG_DEVICE_PUBLIC) &&
+		is_zone_device_page(page) &&
+		page->pgmap->type == MEMORY_DEVICE_PUBLIC;
 }
 
 static inline bool is_pci_p2pdma_page(const struct page *page)
 {
-	return false;
+	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
+		IS_ENABLED(CONFIG_PCI_P2PDMA) &&
+		is_zone_device_page(page) &&
+		page->pgmap->type == MEMORY_DEVICE_PCI_P2PDMA;
 }
-#endif /* CONFIG_DEV_PAGEMAP_OPS */
 
 static inline void get_page(struct page *page)
 {
-- 
2.21.0.dirty

[PATCH v2 3/3] mm: introduce ARCH_HAS_PTE_DEVMAP

[Robin Murphy]

ARCH_HAS_ZONE_DEVICE is somewhat meaningless in itself, and combined
with the long-out-of-date comment can lead to the impression than an
architecture may just enable it (since __add_pages() now "comprehends
device memory" for itself) and expect things to work.

In practice, however, ZONE_DEVICE users have little chance of
functioning correctly without __HAVE_ARCH_PTE_DEVMAP, so let's clean
that up the same way as ARCH_HAS_PTE_SPECIAL and make it the proper
dependency so the real situation is clearer.

Cc: x86@kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Acked-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---

v2: Add review tags.

 arch/powerpc/Kconfig                         | 2 +-
 arch/powerpc/include/asm/book3s/64/pgtable.h | 1 -
 arch/x86/Kconfig                             | 2 +-
 arch/x86/include/asm/pgtable.h               | 4 ++--
 arch/x86/include/asm/pgtable_types.h         | 1 -
 include/linux/mm.h                           | 4 ++--
 include/linux/pfn_t.h                        | 4 ++--
 mm/Kconfig                                   | 5 ++---
 mm/gup.c                                     | 2 +-
 9 files changed, 11 insertions(+), 14 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 5e3d0853c31d..77e1993bba80 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -135,6 +135,7 @@ config PPC
 	select ARCH_HAS_MMIOWB			if PPC64
 	select ARCH_HAS_PHYS_TO_DMA
 	select ARCH_HAS_PMEM_API                if PPC64
+	select ARCH_HAS_PTE_DEVMAP		if PPC_BOOK3S_64
 	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_MEMBARRIER_CALLBACKS
 	select ARCH_HAS_SCALED_CPUTIME		if VIRT_CPU_ACCOUNTING_NATIVE && PPC64
@@ -142,7 +143,6 @@ config PPC
 	select ARCH_HAS_TICK_BROADCAST		if GENERIC_CLOCKEVENTS_BROADCAST
 	select ARCH_HAS_UACCESS_FLUSHCACHE	if PPC64
 	select ARCH_HAS_UBSAN_SANITIZE_ALL
-	select ARCH_HAS_ZONE_DEVICE		if PPC_BOOK3S_64
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
 	select ARCH_MIGHT_HAVE_PC_PARPORT
 	select ARCH_MIGHT_HAVE_PC_SERIO
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 581f91be9dd4..02c22ac8f387 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -90,7 +90,6 @@
 #define _PAGE_SOFT_DIRTY	_RPAGE_SW3 /* software: software dirty tracking */
 #define _PAGE_SPECIAL		_RPAGE_SW2 /* software: special page */
 #define _PAGE_DEVMAP		_RPAGE_SW1 /* software: ZONE_DEVICE page */
-#define __HAVE_ARCH_PTE_DEVMAP
 
 /*
  * Drivers request for cache inhibited pte mapping using _PAGE_NO_CACHE
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 5ad92419be19..ffd50f27f395 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -60,6 +60,7 @@ 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_DEVMAP		if X86_64
 	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_REFCOUNT
 	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
@@ -69,7 +70,6 @@ config X86
 	select ARCH_HAS_STRICT_MODULE_RWX
 	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
 	select ARCH_HAS_UBSAN_SANITIZE_ALL
-	select ARCH_HAS_ZONE_DEVICE		if X86_64
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
 	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
 	select ARCH_MIGHT_HAVE_PC_PARPORT
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 2779ace16d23..89a1f6fd48bf 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -254,7 +254,7 @@ static inline int has_transparent_hugepage(void)
 	return boot_cpu_has(X86_FEATURE_PSE);
 }
 
-#ifdef __HAVE_ARCH_PTE_DEVMAP
+#ifdef CONFIG_ARCH_HAS_PTE_DEVMAP
 static inline int pmd_devmap(pmd_t pmd)
 {
 	return !!(pmd_val(pmd) & _PAGE_DEVMAP);
@@ -715,7 +715,7 @@ static inline int pte_present(pte_t a)
 	return pte_flags(a) & (_PAGE_PRESENT | _PAGE_PROTNONE);
 }
 
-#ifdef __HAVE_ARCH_PTE_DEVMAP
+#ifdef CONFIG_ARCH_HAS_PTE_DEVMAP
 static inline int pte_devmap(pte_t a)
 {
 	return (pte_flags(a) & _PAGE_DEVMAP) == _PAGE_DEVMAP;
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index d6ff0bbdb394..b5e49e6bac63 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -103,7 +103,6 @@
 #if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)
 #define _PAGE_NX	(_AT(pteval_t, 1) << _PAGE_BIT_NX)
 #define _PAGE_DEVMAP	(_AT(u64, 1) << _PAGE_BIT_DEVMAP)
-#define __HAVE_ARCH_PTE_DEVMAP
 #else
 #define _PAGE_NX	(_AT(pteval_t, 0))
 #define _PAGE_DEVMAP	(_AT(pteval_t, 0))
diff --git a/include/linux/mm.h b/include/linux/mm.h
index d76dfb7ac617..fe05c94f23e9 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -504,7 +504,7 @@ struct inode;
 #define page_private(page)		((page)->private)
 #define set_page_private(page, v)	((page)->private = (v))
 
-#if !defined(__HAVE_ARCH_PTE_DEVMAP) || !defined(CONFIG_TRANSPARENT_HUGEPAGE)
+#if !defined(CONFIG_ARCH_HAS_PTE_DEVMAP) || !defined(CONFIG_TRANSPARENT_HUGEPAGE)
 static inline int pmd_devmap(pmd_t pmd)
 {
 	return 0;
@@ -1698,7 +1698,7 @@ static inline void sync_mm_rss(struct mm_struct *mm)
 }
 #endif
 
-#ifndef __HAVE_ARCH_PTE_DEVMAP
+#ifndef CONFIG_ARCH_HAS_PTE_DEVMAP
 static inline int pte_devmap(pte_t pte)
 {
 	return 0;
diff --git a/include/linux/pfn_t.h b/include/linux/pfn_t.h
index 7bb77850c65a..de8bc66b10a4 100644
--- a/include/linux/pfn_t.h
+++ b/include/linux/pfn_t.h
@@ -104,7 +104,7 @@ static inline pud_t pfn_t_pud(pfn_t pfn, pgprot_t pgprot)
 #endif
 #endif
 
-#ifdef __HAVE_ARCH_PTE_DEVMAP
+#ifdef CONFIG_ARCH_HAS_PTE_DEVMAP
 static inline bool pfn_t_devmap(pfn_t pfn)
 {
 	const u64 flags = PFN_DEV|PFN_MAP;
@@ -122,7 +122,7 @@ pmd_t pmd_mkdevmap(pmd_t pmd);
 	defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
 pud_t pud_mkdevmap(pud_t pud);
 #endif
-#endif /* __HAVE_ARCH_PTE_DEVMAP */
+#endif /* CONFIG_ARCH_HAS_PTE_DEVMAP */
 
 #ifdef CONFIG_ARCH_HAS_PTE_SPECIAL
 static inline bool pfn_t_special(pfn_t pfn)
diff --git a/mm/Kconfig b/mm/Kconfig
index 25c71eb8a7db..fcb7ab08e294 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -655,8 +655,7 @@ config IDLE_PAGE_TRACKING
 	  See Documentation/admin-guide/mm/idle_page_tracking.rst for
 	  more details.
 
-# arch_add_memory() comprehends device memory
-config ARCH_HAS_ZONE_DEVICE
+config ARCH_HAS_PTE_DEVMAP
 	bool
 
 config ZONE_DEVICE
@@ -664,7 +663,7 @@ config ZONE_DEVICE
 	depends on MEMORY_HOTPLUG
 	depends on MEMORY_HOTREMOVE
 	depends on SPARSEMEM_VMEMMAP
-	depends on ARCH_HAS_ZONE_DEVICE
+	depends on ARCH_HAS_PTE_DEVMAP
 	select XARRAY_MULTI
 
 	help
diff --git a/mm/gup.c b/mm/gup.c
index f84e22685aaa..72a5c7d1e1a7 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1623,7 +1623,7 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,
 }
 #endif /* CONFIG_ARCH_HAS_PTE_SPECIAL */
 
-#if defined(__HAVE_ARCH_PTE_DEVMAP) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
+#if defined(CONFIG_ARCH_HAS_PTE_DEVMAP) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
 static int __gup_device_huge(unsigned long pfn, unsigned long addr,
 		unsigned long end, struct page **pages, int *nr)
 {
-- 
2.21.0.dirty