[PATCH v2 4/9] mm: move pte_alloc{,_map,_map_lock}() to a separate file

STALE1842d

From: Qi Zheng <hidden>
Date: 2021-08-19 03:20:33
Also in: linux-doc, lkml
Subsystem: arm port, arm64 port (aarch64 architecture), linux for powerpc (32-bit and 64-bit), memory management, memory management - core, parisc architecture, s390 architecture, sparc + ultrasparc (sparc/sparc64), superh, the rest · Maintainers: Russell King, Catalin Marinas, Will Deacon, Madhavan Srinivasan, Andrew Morton, David Hildenbrand, "James E.J. Bottomley", Helge Deller, Heiko Carstens, Vasily Gorbik, Alexander Gordeev, "David S. Miller", Andreas Larsson, Yoshinori Sato, Rich Felker, John Paul Adrian Glaubitz, Linus Torvalds

Revision v2 of 4 in this series.

Revisions (4)

2021-07-18 v1 [diff vs current]
2021-08-19 v2 current
2021-11-10 v3 [diff vs current]
2021-11-10 v3 [diff vs current]

Subsequent patches will modify pte_alloc{,_map,_map_lock}(),
which are the allocate function related to user PTE page
table pages, so move those to a separate file in advance.

This patch contains no functional changes, only some
preparatory work.

Signed-off-by: Qi Zheng <redacted>
---
 arch/arm/mm/pgd.c             |  1 +
 arch/arm64/mm/hugetlbpage.c   |  1 +
 arch/ia64/mm/hugetlbpage.c    |  1 +
 arch/parisc/mm/hugetlbpage.c  |  1 +
 arch/powerpc/mm/hugetlbpage.c |  1 +
 arch/s390/mm/gmap.c           |  1 +
 arch/s390/mm/pgtable.c        |  1 +
 arch/sh/mm/hugetlbpage.c      |  1 +
 arch/sparc/mm/hugetlbpage.c   |  1 +
 include/linux/mm.h            | 11 ----------
 include/linux/pte_ref.h       | 29 ++++++++++++++++++++++++++
 mm/Makefile                   |  3 ++-
 mm/internal.h                 |  1 +
 mm/memory.c                   | 38 ----------------------------------
 mm/pte_ref.c                  | 48 +++++++++++++++++++++++++++++++++++++++++++
 15 files changed, 89 insertions(+), 50 deletions(-)
 create mode 100644 include/linux/pte_ref.h
 create mode 100644 mm/pte_ref.c

diff --git a/arch/arm/mm/pgd.c b/arch/arm/mm/pgd.c
index f8e9bc58a84f..dcac1124e8bd 100644
--- a/arch/arm/mm/pgd.c
+++ b/arch/arm/mm/pgd.c

@@ -8,6 +8,7 @@
 #include <linux/gfp.h>
 #include <linux/highmem.h>
 #include <linux/slab.h>
+#include <linux/pte_ref.h>
 
 #include <asm/cp15.h>
 #include <asm/pgalloc.h>

diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 23505fc35324..6c8177647053 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c

@@ -14,6 +14,7 @@
 #include <linux/pagemap.h>
 #include <linux/err.h>
 #include <linux/sysctl.h>
+#include <linux/pte_ref.h>
 #include <asm/mman.h>
 #include <asm/tlb.h>
 #include <asm/tlbflush.h>

diff --git a/arch/ia64/mm/hugetlbpage.c b/arch/ia64/mm/hugetlbpage.c
index f993cb36c062..d343639db1ad 100644
--- a/arch/ia64/mm/hugetlbpage.c
+++ b/arch/ia64/mm/hugetlbpage.c

@@ -17,6 +17,7 @@
 #include <linux/module.h>
 #include <linux/sysctl.h>
 #include <linux/log2.h>
+#include <linux/pte_ref.h>
 #include <asm/mman.h>
 #include <asm/tlb.h>
 #include <asm/tlbflush.h>

diff --git a/arch/parisc/mm/hugetlbpage.c b/arch/parisc/mm/hugetlbpage.c
index d1d3990b83f6..4f6044d6b4bd 100644
--- a/arch/parisc/mm/hugetlbpage.c
+++ b/arch/parisc/mm/hugetlbpage.c

@@ -13,6 +13,7 @@
 #include <linux/hugetlb.h>
 #include <linux/pagemap.h>
 #include <linux/sysctl.h>
+#include <linux/pte_ref.h>
 
 #include <asm/mman.h>
 #include <asm/tlb.h>

diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 9a75ba078e1b..1afb8f552bcf 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c

@@ -19,6 +19,7 @@
 #include <linux/swap.h>
 #include <linux/swapops.h>
 #include <linux/kmemleak.h>
+#include <linux/pte_ref.h>
 #include <asm/pgalloc.h>
 #include <asm/tlb.h>
 #include <asm/setup.h>

diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
index 9bb2c7512cd5..c1826d74773a 100644
--- a/arch/s390/mm/gmap.c
+++ b/arch/s390/mm/gmap.c

@@ -18,6 +18,7 @@
 #include <linux/ksm.h>
 #include <linux/mman.h>
 #include <linux/pgtable.h>
+#include <linux/pte_ref.h>
 
 #include <asm/pgalloc.h>
 #include <asm/gmap.h>

diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index eec3a9d7176e..594a6d6888e3 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c

@@ -18,6 +18,7 @@
 #include <linux/sysctl.h>
 #include <linux/ksm.h>
 #include <linux/mman.h>
+#include <linux/pte_ref.h>
 
 #include <asm/tlb.h>
 #include <asm/tlbflush.h>

diff --git a/arch/sh/mm/hugetlbpage.c b/arch/sh/mm/hugetlbpage.c
index 999ab5916e69..6a593ab248b7 100644
--- a/arch/sh/mm/hugetlbpage.c
+++ b/arch/sh/mm/hugetlbpage.c

@@ -15,6 +15,7 @@
 #include <linux/hugetlb.h>
 #include <linux/pagemap.h>
 #include <linux/sysctl.h>
+#include <linux/pte_ref.h>
 
 #include <asm/mman.h>
 #include <asm/tlb.h>

diff --git a/arch/sparc/mm/hugetlbpage.c b/arch/sparc/mm/hugetlbpage.c
index 0f49fada2093..4b9119825264 100644
--- a/arch/sparc/mm/hugetlbpage.c
+++ b/arch/sparc/mm/hugetlbpage.c

@@ -11,6 +11,7 @@
 #include <linux/hugetlb.h>
 #include <linux/pagemap.h>
 #include <linux/sysctl.h>
+#include <linux/pte_ref.h>
 
 #include <asm/mman.h>
 #include <asm/pgalloc.h>

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 57e48217bd71..369d4283de49 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h

@@ -2245,7 +2245,6 @@ static inline void mm_inc_nr_ptes(struct mm_struct *mm) {}
 static inline void mm_dec_nr_ptes(struct mm_struct *mm) {}
 #endif
 
-int __pte_alloc(struct mm_struct *mm, pmd_t *pmd);
 int __pte_alloc_kernel(pmd_t *pmd);
 
 #if defined(CONFIG_MMU)

@@ -2371,15 +2370,6 @@ static inline void pgtable_pte_page_dtor(struct page *page)
 	pte_unmap(pte);					\
 } while (0)
 
-#define pte_alloc(mm, pmd) (unlikely(pmd_none(*(pmd))) && __pte_alloc(mm, pmd))
-
-#define pte_alloc_map(mm, pmd, address)			\
-	(pte_alloc(mm, pmd) ? NULL : pte_offset_map(pmd, address))
-
-#define pte_alloc_map_lock(mm, pmd, address, ptlp)	\
-	(pte_alloc(mm, pmd) ?			\
-		 NULL : pte_offset_map_lock(mm, pmd, address, ptlp))
-
 #define pte_alloc_kernel(pmd, address)			\
 	((unlikely(pmd_none(*(pmd))) && __pte_alloc_kernel(pmd))? \
 		NULL: pte_offset_kernel(pmd, address))

@@ -2471,7 +2461,6 @@ static inline spinlock_t *pud_lock(struct mm_struct *mm, pud_t *pud)
 	return ptl;
 }
 
-extern void pmd_install(struct mm_struct *mm, pmd_t *pmd, pgtable_t *pte);
 extern void __init pagecache_init(void);
 extern void __init free_area_init_memoryless_node(int nid);
 extern void free_initmem(void);

diff --git a/include/linux/pte_ref.h b/include/linux/pte_ref.h
new file mode 100644
index 000000000000..60b752dd7846
--- /dev/null
+++ b/include/linux/pte_ref.h

@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Free user PTE page table pages
+ *
+ * Copyright (c) 2021, ByteDance. All rights reserved.
+ *
+ * 	Author: Qi Zheng <zhengqi.arch@bytedance.com>
+ */
+#ifndef _LINUX_PTE_REF_H
+#define _LINUX_PTE_REF_H
+
+#include <linux/mm.h>
+#include <linux/pgtable.h>
+#include <asm/pgalloc.h>
+
+void pmd_install(struct mm_struct *mm, pmd_t *pmd, pgtable_t *pte);
+int __pte_alloc(struct mm_struct *mm, pmd_t *pmd);
+
+#define pte_alloc(mm, pmd) (unlikely(pmd_none(*(pmd))) && __pte_alloc(mm, pmd))
+
+#define pte_alloc_map(mm, pmd, address)			\
+	(pte_alloc(mm, pmd) ? NULL : pte_offset_map(pmd, address))
+
+#define pte_alloc_map_lock(mm, pmd, address, ptlp)	\
+	(pte_alloc(mm, pmd) ?				\
+		 NULL : pte_offset_map_lock(mm, pmd, address, ptlp))
+
+#endif
+

diff --git a/mm/Makefile b/mm/Makefile
index 970604ea97dd..5cdbfaa2a7b5 100644
--- a/mm/Makefile
+++ b/mm/Makefile

@@ -38,7 +38,8 @@ mmu-y			:= nommu.o
 mmu-$(CONFIG_MMU)	:= highmem.o memory.o mincore.o \
 			   mlock.o mmap.o mmu_gather.o mprotect.o mremap.o \
 			   msync.o page_vma_mapped.o pagewalk.o \
-			   pgtable-generic.o rmap.o vmalloc.o ioremap.o
+			   pgtable-generic.o rmap.o vmalloc.o ioremap.o \
+			   pte_ref.o
 
 
 ifdef CONFIG_CROSS_MEMORY_ATTACH

diff --git a/mm/internal.h b/mm/internal.h
index b1001ebeb286..c1e23fa563a7 100644
--- a/mm/internal.h
+++ b/mm/internal.h

@@ -11,6 +11,7 @@
 #include <linux/mm.h>
 #include <linux/pagemap.h>
 #include <linux/tracepoint-defs.h>
+#include <linux/pte_ref.h>
 
 /*
  * The set of flags that only affect watermark checking and reclaim

diff --git a/mm/memory.c b/mm/memory.c
index d2aaa85b840c..265b841cc7f9 100644
--- a/mm/memory.c
+++ b/mm/memory.c

@@ -433,44 +433,6 @@ void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma,
 	}
 }
 
-void pmd_install(struct mm_struct *mm, pmd_t *pmd, pgtable_t *pte)
-{
-	spinlock_t *ptl = pmd_lock(mm, pmd);
-
-	if (likely(pmd_none(*pmd))) {	/* Has another populated it ? */
-		mm_inc_nr_ptes(mm);
-		/*
-		 * Ensure all pte setup (eg. pte page lock and page clearing) are
-		 * visible before the pte is made visible to other CPUs by being
-		 * put into page tables.
-		 *
-		 * The other side of the story is the pointer chasing in the page
-		 * table walking code (when walking the page table without locking;
-		 * ie. most of the time). Fortunately, these data accesses consist
-		 * of a chain of data-dependent loads, meaning most CPUs (alpha
-		 * being the notable exception) will already guarantee loads are
-		 * seen in-order. See the alpha page table accessors for the
-		 * smp_rmb() barriers in page table walking code.
-		 */
-		smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
-		pmd_populate(mm, pmd, *pte);
-		*pte = NULL;
-	}
-	spin_unlock(ptl);
-}
-
-int __pte_alloc(struct mm_struct *mm, pmd_t *pmd)
-{
-	pgtable_t new = pte_alloc_one(mm);
-	if (!new)
-		return -ENOMEM;
-
-	pmd_install(mm, pmd, &new);
-	if (new)
-		pte_free(mm, new);
-	return 0;
-}
-
 int __pte_alloc_kernel(pmd_t *pmd)
 {
 	pte_t *new = pte_alloc_one_kernel(&init_mm);

diff --git a/mm/pte_ref.c b/mm/pte_ref.c
new file mode 100644
index 000000000000..07a73b5521cc
--- /dev/null
+++ b/mm/pte_ref.c

@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Free user PTE page table pages
+ *
+ * Copyright (c) 2021, ByteDance. All rights reserved.
+ *
+ * 	Author: Qi Zheng <zhengqi.arch@bytedance.com>
+ */
+
+#include <linux/pte_ref.h>
+
+void pmd_install(struct mm_struct *mm, pmd_t *pmd, pgtable_t *pte)
+{
+	spinlock_t *ptl = pmd_lock(mm, pmd);
+
+	if (likely(pmd_none(*pmd))) {	/* Has another populated it ? */
+		mm_inc_nr_ptes(mm);
+		/*
+		 * Ensure all pte setup (eg. pte page lock and page clearing) are
+		 * visible before the pte is made visible to other CPUs by being
+		 * put into page tables.
+		 *
+		 * The other side of the story is the pointer chasing in the page
+		 * table walking code (when walking the page table without locking;
+		 * ie. most of the time). Fortunately, these data accesses consist
+		 * of a chain of data-dependent loads, meaning most CPUs (alpha
+		 * being the notable exception) will already guarantee loads are
+		 * seen in-order. See the alpha page table accessors for the
+		 * smp_rmb() barriers in page table walking code.
+		 */
+		smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
+		pmd_populate(mm, pmd, *pte);
+		*pte = NULL;
+	}
+	spin_unlock(ptl);
+}
+
+int __pte_alloc(struct mm_struct *mm, pmd_t *pmd)
+{
+	pgtable_t new = pte_alloc_one(mm);
+	if (!new)
+		return -ENOMEM;
+
+	pmd_install(mm, pmd, &new);
+	if (new)
+		pte_free(mm, new);
+	return 0;
+}

-- 
2.11.0

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