These vma_merge() callers will pass mm, anon_vma and file, they all from
vma. There is no need to pass three parameters at the same time.
We will find the current vma in vma_merge(). If we pass the original vma
to vma_merge(), the current vma is actually the original vma or NULL.
So we didn't need to find the current vma with find_vma_intersection().
Pass vma to vma_merge(), and add a check to make sure the current vma
is an existing vma.
Signed-off-by: Yajun Deng <yajun.deng@xxxxxxxxx>
---
mm/mmap.c | 37 +++++++++++++++++--------------------
1 file changed, 17 insertions(+), 20 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index 49d25172eac8..7e00ae4f39e3 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -860,14 +860,16 @@ can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
* area is returned, or the function will return NULL
*/
static struct vm_area_struct
-*vma_merge(struct vma_iterator *vmi, struct mm_struct *mm,
- struct vm_area_struct *prev, unsigned long addr, unsigned long end,
- unsigned long vm_flags, struct anon_vma *anon_vma, struct file *file,
- pgoff_t pgoff, struct mempolicy *policy,
+*vma_merge(struct vma_iterator *vmi, struct vm_area_struct *prev,
+ struct vm_area_struct *curr, unsigned long addr, unsigned long end,
+ unsigned long vm_flags, pgoff_t pgoff, struct mempolicy *policy,
struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
struct anon_vma_name *anon_name)
{
- struct vm_area_struct *curr, *next, *res;
+ struct mm_struct *mm = curr->vm_mm;
+ struct anon_vma *anon_vma = curr->anon_vma;
+ struct file *file = curr->vm_file;
+ struct vm_area_struct *next = NULL, *res;
struct vm_area_struct *vma, *adjust, *remove, *remove2;
struct vm_area_struct *anon_dup = NULL;
struct vma_prepare vp;
@@ -889,13 +891,12 @@ static struct vm_area_struct
return NULL;
/* Does the input range span an existing VMA? (cases 5 - 8) */
- curr = find_vma_intersection(mm, prev ? prev->vm_end : 0, end);
+ if (prev == curr || addr != curr->vm_start || end > curr->vm_end)
+ curr = NULL;
if (!curr || /* cases 1 - 4 */
end == curr->vm_end) /* cases 6 - 8, adjacent VMA */
- next = vma_lookup(mm, end);
- else
- next = NULL; /* case 5 */
+ next = vma_lookup(mm, end); /* NULL case 5 */
if (prev) {
vma_start = prev->vm_start;
@@ -919,7 +920,6 @@ static struct vm_area_struct
/* Verify some invariant that must be enforced by the caller. */
VM_WARN_ON(prev && addr <= prev->vm_start);
- VM_WARN_ON(curr && (addr != curr->vm_start || end > curr->vm_end));
VM_WARN_ON(addr >= end);
if (!merge_prev && !merge_next)
@@ -2424,9 +2424,8 @@ struct vm_area_struct *vma_modify(struct vma_iterator *vmi,
pgoff_t pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
struct vm_area_struct *merged;
- merged = vma_merge(vmi, vma->vm_mm, prev, start, end, vm_flags,
- vma->anon_vma, vma->vm_file, pgoff, policy,
- uffd_ctx, anon_name);
+ merged = vma_merge(vmi, prev, vma, start, end, vm_flags,
+ pgoff, policy, uffd_ctx, anon_name);
if (merged)
return merged;
@@ -2456,9 +2455,8 @@ static struct vm_area_struct
struct vm_area_struct *vma, unsigned long start,
unsigned long end, pgoff_t pgoff)
{
- return vma_merge(vmi, vma->vm_mm, prev, start, end, vma->vm_flags,
- vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
- vma->vm_userfaultfd_ctx, anon_vma_name(vma));
+ return vma_merge(vmi, prev, vma, start, end, vma->vm_flags, pgoff,
+ vma_policy(vma), vma->vm_userfaultfd_ctx, anon_vma_name(vma));
}
/*
@@ -2472,10 +2470,9 @@ struct vm_area_struct *vma_merge_extend(struct vma_iterator *vmi,
pgoff_t pgoff = vma->vm_pgoff + vma_pages(vma);
/* vma is specified as prev, so case 1 or 2 will apply. */
- return vma_merge(vmi, vma->vm_mm, vma, vma->vm_end, vma->vm_end + delta,
- vma->vm_flags, vma->anon_vma, vma->vm_file, pgoff,
- vma_policy(vma), vma->vm_userfaultfd_ctx,
- anon_vma_name(vma));
+ return vma_merge(vmi, vma, vma, vma->vm_end, vma->vm_end + delta,
+ vma->vm_flags, pgoff, vma_policy(vma),
+ vma->vm_userfaultfd_ctx, anon_vma_name(vma));
}
/*
--
2.25.1
