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 <kir...@shutemov.name>
Signed-off-by: Peter Xu <pet...@redhat.com>
---
 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

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