The patch titled
Subject: mm/mmap: Add case 9 in vma_merge()
has been added to the -mm mm-unstable branch. Its filename is
mm-mmap-add-case-9-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-add-case-9-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: Add case 9 in vma_merge()
Date: Sun, 18 Feb 2024 16:50:28 +0800
If the prev vma exists and the end is less than the end of prev, we
can return NULL immediately. This reduces unnecessary operations.
Link: https://lkml.kernel.org/r/20240218085028.3294332-1-yajun.deng@xxxxxxxxx
Signed-off-by: Yajun Deng <yajun.deng@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mmap.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/mm/mmap.c~mm-mmap-add-case-9-in-vma_merge
+++ a/mm/mmap.c
@@ -827,7 +827,7 @@ can_vma_merge_after(struct vm_area_struc
*
* **** **** ****
* PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPCCCCCC
- * cannot merge might become might become
+ * cannot merge 9 might become might become
* PPNNNNNNNNNN PPPPPPPPPPCC
* mmap, brk or case 4 below case 5 below
* mremap move:
@@ -890,6 +890,9 @@ static struct vm_area_struct
if (vm_flags & VM_SPECIAL)
return NULL;
+ if (prev && end < prev->vm_end) /* case 9 */
+ return NULL;
+
/* Does the input range span an existing VMA? (cases 5 - 8) */
curr = find_vma_intersection(mm, prev ? prev->vm_end : 0, end);
_
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-use-sz_8k-128k-helper-macro.patch
mm-mmap-pass-vma-to-vma_merge.patch
mm-mmap-add-case-9-in-vma_merge.patch
