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

[Peter Xu]

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