The quilt patch titled
Subject: mm/vma: the pgoff is correct if can_merge_right
has been removed from the -mm tree. Its filename was
mm-vma-the-pgoff-is-correct-if-can_merge_right.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Wei Yang <richard.weiyang@xxxxxxxxx>
Subject: mm/vma: the pgoff is correct if can_merge_right
Date: Thu, 24 Oct 2024 09:33:47 +0000
By this point can_vma_merge_right() must have returned true, which implies
can_vma_merge_before() also returned true, which already asserts that the
pgoff is as expected for a merge with the following VMA, thus this
assignment is redundant.
Below is a more detail explanation.
Current definition of can_vma_merge_right() is:
static bool can_vma_merge_right(struct vma_merge_struct *vmg,
bool can_merge_left)
{
if (!vmg->next || vmg->end != vmg->next->vm_start ||
!can_vma_merge_before(vmg))
return false;
...
}
And:
static bool can_vma_merge_before(struct vma_merge_struct *vmg)
{
pgoff_t pglen = PHYS_PFN(vmg->end - vmg->start);
...
if (vmg->next->vm_pgoff == vmg->pgoff + pglen)
return true;
...
}
Which implies vmg->pgoff == vmg->next->vm_pgoff - pglen.
None of these values are changed between the check and prior assignment,
so this was an entirely redundant assignment.
[akpm@xxxxxxxxxxxxxxxxxxxx: remove now-unused local]
[lorenzo.stoakes@xxxxxxxxxx: rephrase the changelog]
Link: https://lkml.kernel.org/r/20241024093347.18057-1-richard.weiyang@xxxxxxxxx
Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vma.c | 3 ---
1 file changed, 3 deletions(-)
--- a/mm/vma.c~mm-vma-the-pgoff-is-correct-if-can_merge_right
+++ a/mm/vma.c
@@ -962,9 +962,7 @@ struct vm_area_struct *vma_merge_new_ran
{
struct vm_area_struct *prev = vmg->prev;
struct vm_area_struct *next = vmg->next;
- unsigned long start = vmg->start;
unsigned long end = vmg->end;
- pgoff_t pglen = PHYS_PFN(end - start);
bool can_merge_left, can_merge_right;
bool just_expand = vmg->merge_flags & VMG_FLAG_JUST_EXPAND;
@@ -986,7 +984,6 @@ struct vm_area_struct *vma_merge_new_ran
if (can_merge_right) {
vmg->end = next->vm_end;
vmg->vma = next;
- vmg->pgoff = next->vm_pgoff - pglen;
}
/* If we can merge with the previous VMA, adjust vmg accordingly. */
_
Patches currently in -mm which might be from richard.weiyang@xxxxxxxxx are
mm-mlock-set-the-correct-prev-on-failure.patch
maple_tree-print-empty-for-an-empty-tree-on-mt_dump.patch
maple_tree-the-return-value-of-mas_root_expand-is-not-used.patch
maple_tree-not-necessary-to-check-index-last-again.patch
maple_tree-refine-mas_store_root-on-storing-null.patch
maple_tree-add-a-test-checking-storing-null.patch
