The patch titled
Subject: mm/mmap: remove find_vma_intersection() in vma_merge()
has been added to the -mm mm-unstable branch. Its filename is
mm-mmap-remove-find_vma_intersection-in-vma_merge.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mmap-remove-find_vma_intersection-in-vma_merge.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Yajun Deng <yajun.deng@xxxxxxxxx>
Subject: mm/mmap: remove find_vma_intersection() in vma_merge()
Date: Thu, 25 Jan 2024 11:49:22 +0800
We need to find the current vma by find_vma_intersection() in vma_merge().
Since the src vma was passed, we can add a check to figure out if the
current vma is NULL or the src vma directly.
Remove find_vma_intersection() in vma_merge(). And initialize the next to
NULL when defining it.
Link: https://lkml.kernel.org/r/20240125034922.1004671-3-yajun.deng@xxxxxxxxx
Signed-off-by: Yajun Deng <yajun.deng@xxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Christian Brauner <brauner@xxxxxxxxxx>
Cc: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Cc: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mmap.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
--- a/mm/mmap.c~mm-mmap-remove-find_vma_intersection-in-vma_merge
+++ a/mm/mmap.c
@@ -869,7 +869,7 @@ static struct vm_area_struct
struct mm_struct *mm = src->vm_mm;
struct anon_vma *anon_vma = src->anon_vma;
struct file *file = src->vm_file;
- struct vm_area_struct *curr, *next, *res;
+ struct vm_area_struct *curr = src, *next = NULL, *res;
struct vm_area_struct *vma, *adjust, *remove, *remove2;
struct vm_area_struct *anon_dup = NULL;
struct vma_prepare vp;
@@ -890,14 +890,18 @@ static struct vm_area_struct
if (vm_flags & VM_SPECIAL)
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 the current vma and the prev vma are the same vma, it
+ * means the current vma is NULL.
+ * Does the input range span an existing VMA? (cases 5 - 8)
+ */
+ 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 */
+ /* case 5 set to NULL above */
if (prev) {
vma_start = prev->vm_start;
@@ -921,7 +925,6 @@ 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)
_
Patches currently in -mm which might be from yajun.deng@xxxxxxxxx are
mm-mmap-simplify-vma-link-and-unlink.patch
mm-mmap-introduce-vma_set_range.patch
mm-mmap-pass-vma-to-vma_merge.patch
mm-mmap-remove-find_vma_intersection-in-vma_merge.patch
