[PATCH v4 3/5] mm: make vma_merge() and split_vma() internal

From: Lorenzo Stoakes
Date: Wed Oct 11 2023 - 13:04:57 EST


Now the common pattern of - attempting a merge via vma_merge() and should
this fail splitting VMAs via split_vma() - has been abstracted, the former
can be placed into mm/internal.h and the latter made static.

In addition, the split_vma() nommu variant also need not be exported.

Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
---
include/linux/mm.h | 9 ---------
mm/internal.h | 9 +++++++++
mm/mmap.c | 8 ++++----
mm/nommu.c | 4 ++--
4 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 83ee1f35febe..74d7547ffb70 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3237,16 +3237,7 @@ extern int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma,
struct vm_area_struct *next);
extern int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma,
unsigned long start, unsigned long end, pgoff_t pgoff);
-extern struct vm_area_struct *vma_merge(struct vma_iterator *vmi,
- struct mm_struct *, struct vm_area_struct *prev, unsigned long addr,
- unsigned long end, unsigned long vm_flags, struct anon_vma *,
- struct file *, pgoff_t, struct mempolicy *, struct vm_userfaultfd_ctx,
- struct anon_vma_name *);
extern struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *);
-extern int __split_vma(struct vma_iterator *vmi, struct vm_area_struct *,
- unsigned long addr, int new_below);
-extern int split_vma(struct vma_iterator *vmi, struct vm_area_struct *,
- unsigned long addr, int new_below);
extern int insert_vm_struct(struct mm_struct *, struct vm_area_struct *);
extern void unlink_file_vma(struct vm_area_struct *);
extern struct vm_area_struct *copy_vma(struct vm_area_struct **,
diff --git a/mm/internal.h b/mm/internal.h
index 3a72975425bb..ddaeb9f2d9d7 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -1011,6 +1011,15 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
unsigned long addr, pmd_t *pmd,
unsigned int flags);

+/*
+ * mm/mmap.c
+ */
+struct vm_area_struct *vma_merge(struct vma_iterator *vmi,
+ struct mm_struct *, struct vm_area_struct *prev, unsigned long addr,
+ unsigned long end, unsigned long vm_flags, struct anon_vma *,
+ struct file *, pgoff_t, struct mempolicy *, struct vm_userfaultfd_ctx,
+ struct anon_vma_name *);
+
enum {
/* mark page accessed */
FOLL_TOUCH = 1 << 16,
diff --git a/mm/mmap.c b/mm/mmap.c
index bca685820763..a516f2412f79 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2346,8 +2346,8 @@ static void unmap_region(struct mm_struct *mm, struct ma_state *mas,
* has already been checked or doesn't make sense to fail.
* VMA Iterator will point to the end VMA.
*/
-int __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
- unsigned long addr, int new_below)
+static int __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
+ unsigned long addr, int new_below)
{
struct vma_prepare vp;
struct vm_area_struct *new;
@@ -2428,8 +2428,8 @@ int __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
* Split a vma into two pieces at address 'addr', a new vma is allocated
* either for the first part or the tail.
*/
-int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
- unsigned long addr, int new_below)
+static int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
+ unsigned long addr, int new_below)
{
if (vma->vm_mm->map_count >= sysctl_max_map_count)
return -ENOMEM;
diff --git a/mm/nommu.c b/mm/nommu.c
index f9553579389b..fc4afe924ad5 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1305,8 +1305,8 @@ SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
* split a vma into two pieces at address 'addr', a new vma is allocated either
* for the first part or the tail.
*/
-int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
- unsigned long addr, int new_below)
+static int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
+ unsigned long addr, int new_below)
{
struct vm_area_struct *new;
struct vm_region *region;
--
2.42.0