[PATCH] mm: Remove src/dst mm parameter in copy_page_range()

From: Peter Xu
Date: Wed Sep 30 2020 - 16:49:55 EST


Both of the mm pointers are not needed after commit 7a4830c380f3 ("mm/fork:
Pass new vma pointer into copy_page_range()").

Reported-by: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx>
Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
---
include/linux/mm.h | 3 +--
kernel/fork.c | 2 +-
mm/memory.c | 43 ++++++++++++++++++++++---------------------
3 files changed, 24 insertions(+), 24 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 16b799a0522c..8a0ec8dce5f6 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1645,8 +1645,7 @@ struct mmu_notifier_range;

void free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
unsigned long end, unsigned long floor, unsigned long ceiling);
-int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
- struct vm_area_struct *vma, struct vm_area_struct *new);
+int copy_page_range(struct vm_area_struct *vma, struct vm_area_struct *new);
int follow_pte_pmd(struct mm_struct *mm, unsigned long address,
struct mmu_notifier_range *range,
pte_t **ptepp, pmd_t **pmdpp, spinlock_t **ptlp);
diff --git a/kernel/fork.c b/kernel/fork.c
index da8d360fb032..5f42d4afe0ae 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -589,7 +589,7 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,

mm->map_count++;
if (!(tmp->vm_flags & VM_WIPEONFORK))
- retval = copy_page_range(mm, oldmm, mpnt, tmp);
+ retval = copy_page_range(mpnt, tmp);

if (tmp->vm_ops && tmp->vm_ops->open)
tmp->vm_ops->open(tmp);
diff --git a/mm/memory.c b/mm/memory.c
index fcfc4ca36eba..251bb5082f4e 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -957,11 +957,12 @@ page_copy_prealloc(struct mm_struct *src_mm, struct vm_area_struct *vma,
return new_page;
}

-static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
- pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
- struct vm_area_struct *new,
+static int copy_pte_range(pmd_t *dst_pmd, pmd_t *src_pmd,
+ struct vm_area_struct *vma, struct vm_area_struct *new,
unsigned long addr, unsigned long end)
{
+ struct mm_struct *dst_mm = new->vm_mm;
+ struct mm_struct *src_mm = vma->vm_mm;
pte_t *orig_src_pte, *orig_dst_pte;
pte_t *src_pte, *dst_pte;
spinlock_t *src_ptl, *dst_ptl;
@@ -1061,11 +1062,12 @@ static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
return ret;
}

-static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
- pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
- struct vm_area_struct *new,
+static inline int copy_pmd_range(pud_t *dst_pud, pud_t *src_pud,
+ struct vm_area_struct *vma, struct vm_area_struct *new,
unsigned long addr, unsigned long end)
{
+ struct mm_struct *dst_mm = new->vm_mm;
+ struct mm_struct *src_mm = vma->vm_mm;
pmd_t *src_pmd, *dst_pmd;
unsigned long next;

@@ -1089,18 +1091,18 @@ static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src
}
if (pmd_none_or_clear_bad(src_pmd))
continue;
- if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
- vma, new, addr, next))
+ if (copy_pte_range(dst_pmd, src_pmd, vma, new, addr, next))
return -ENOMEM;
} while (dst_pmd++, src_pmd++, addr = next, addr != end);
return 0;
}

-static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
- p4d_t *dst_p4d, p4d_t *src_p4d, struct vm_area_struct *vma,
- struct vm_area_struct *new,
+static inline int copy_pud_range(p4d_t *dst_p4d, p4d_t *src_p4d,
+ struct vm_area_struct *vma, struct vm_area_struct *new,
unsigned long addr, unsigned long end)
{
+ struct mm_struct *dst_mm = new->vm_mm;
+ struct mm_struct *src_mm = vma->vm_mm;
pud_t *src_pud, *dst_pud;
unsigned long next;

@@ -1124,18 +1126,17 @@ static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src
}
if (pud_none_or_clear_bad(src_pud))
continue;
- if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
- vma, new, addr, next))
+ if (copy_pmd_range(dst_pud, src_pud, vma, new, addr, next))
return -ENOMEM;
} while (dst_pud++, src_pud++, addr = next, addr != end);
return 0;
}

-static inline int copy_p4d_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
- pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
- struct vm_area_struct *new,
+static inline int copy_p4d_range(pgd_t *dst_pgd, pgd_t *src_pgd,
+ struct vm_area_struct *vma, struct vm_area_struct *new,
unsigned long addr, unsigned long end)
{
+ struct mm_struct *dst_mm = new->vm_mm;
p4d_t *src_p4d, *dst_p4d;
unsigned long next;

@@ -1147,20 +1148,20 @@ static inline int copy_p4d_range(struct mm_struct *dst_mm, struct mm_struct *src
next = p4d_addr_end(addr, end);
if (p4d_none_or_clear_bad(src_p4d))
continue;
- if (copy_pud_range(dst_mm, src_mm, dst_p4d, src_p4d,
- vma, new, addr, next))
+ if (copy_pud_range(dst_p4d, src_p4d, vma, new, addr, next))
return -ENOMEM;
} while (dst_p4d++, src_p4d++, addr = next, addr != end);
return 0;
}

-int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
- struct vm_area_struct *vma, struct vm_area_struct *new)
+int copy_page_range(struct vm_area_struct *vma, struct vm_area_struct *new)
{
pgd_t *src_pgd, *dst_pgd;
unsigned long next;
unsigned long addr = vma->vm_start;
unsigned long end = vma->vm_end;
+ struct mm_struct *dst_mm = new->vm_mm;
+ struct mm_struct *src_mm = vma->vm_mm;
struct mmu_notifier_range range;
bool is_cow;
int ret;
@@ -1209,7 +1210,7 @@ int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
next = pgd_addr_end(addr, end);
if (pgd_none_or_clear_bad(src_pgd))
continue;
- if (unlikely(copy_p4d_range(dst_mm, src_mm, dst_pgd, src_pgd,
+ if (unlikely(copy_p4d_range(dst_pgd, src_pgd,
vma, new, addr, next))) {
ret = -ENOMEM;
break;
--
2.26.2