[PATCH 2/2] mm/mmap: leverage vma_rb_erase_ignore() to implement vma_rb_erase()

From: Wei Yang
Date: Sun Aug 09 2020 - 19:21:10 EST


These two functions share the same logic except ignore a different vma.

Let's reuse the code.

Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxxxxxxxxxx>
---
mm/mmap.c | 16 +++++++---------
1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index ec780925da94..90b1298d4222 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -474,8 +474,12 @@ static __always_inline void vma_rb_erase_ignore(struct vm_area_struct *vma,
{
/*
* All rb_subtree_gap values must be consistent prior to erase,
- * with the possible exception of the "next" vma being erased if
- * next->vm_start was reduced.
+ * with the possible exception of
+ *
+ * a. the "next" vma being erased if next->vm_start was reduced in
+ * __vma_adjust() -> __vma_unlink()
+ * b. the vma being erased in detach_vmas_to_be_unmapped() ->
+ * vma_rb_erase()
*/
validate_mm_rb(root, ignore);

@@ -485,13 +489,7 @@ static __always_inline void vma_rb_erase_ignore(struct vm_area_struct *vma,
static __always_inline void vma_rb_erase(struct vm_area_struct *vma,
struct rb_root *root)
{
- /*
- * All rb_subtree_gap values must be consistent prior to erase,
- * with the possible exception of the vma being erased.
- */
- validate_mm_rb(root, vma);
-
- __vma_rb_erase(vma, root);
+ vma_rb_erase_ignore(vma, root, vma);
}

/*
--
2.20.1 (Apple Git-117)