[PATCH 25/30] mm/vma: update vmg_adjust_set_range() to offset pgoff instead
From: Lorenzo Stoakes <ljs@kernel.org>
Date: 2026-06-29 12:25:10
Also in:
damon, dri-devel, kvm, linux-arm-msm, linux-fsdevel, linux-iommu, linux-mm, linux-perf-users, linux-tegra, lkml, nvdimm
Subsystem:
memory management, memory mapping, the rest · Maintainers:
Andrew Morton, Liam R. Howlett, Lorenzo Stoakes, Linus Torvalds
We are calculating the pgoff as an offset, since we have vma_add_pgoff() and vma_sub_pgoff() available, just offset this value directly and use __vma_set_range() for vma->vm_[start, end] values. We take care to update the range before offsetting the page offset, so the adjusted VMA's vm_start and vm_pgoff are mutually consistent at the point the page offset helpers operate - this matters once vma_set_pgoff() comes to assert invariants which relate the two. Doing so lays the foundation for future work which allows for use of virtual page offsets for MAP_PRIVATE-file backed mappings. No functional change intended. Signed-off-by: Lorenzo Stoakes <ljs@kernel.org> --- mm/vma.c | 15 ++++----------- 1 file changed, 4 insertions(+), 11 deletions(-)
diff --git a/mm/vma.c b/mm/vma.c
index e3355eab11f2..0579fc8c9bd5 100644
--- a/mm/vma.c
+++ b/mm/vma.c@@ -714,9 +714,6 @@ void validate_mm(struct mm_struct *mm) */ static void vmg_adjust_set_range(struct vma_merge_struct *vmg) { - struct vm_area_struct *adjust; - pgoff_t pgoff; - if (vmg->__adjust_middle_start) { /* * vmg->start vmg->end
@@ -735,8 +732,8 @@ static void vmg_adjust_set_range(struct vma_merge_struct *vmg) struct vm_area_struct *middle = vmg->middle; const unsigned long delta = vmg->end - middle->vm_start; - pgoff = vma_start_pgoff(middle) + (delta >> PAGE_SHIFT); - adjust = middle; + __vma_set_range(middle, vmg->end, middle->vm_end); + vma_add_pgoff(middle, delta >> PAGE_SHIFT); } else if (vmg->__adjust_next_start) { /* * Originally:
@@ -764,13 +761,9 @@ static void vmg_adjust_set_range(struct vma_merge_struct *vmg) struct vm_area_struct *next = vmg->next; const unsigned long delta = next->vm_start - vmg->end; - pgoff = vma_start_pgoff(next) - (delta >> PAGE_SHIFT); - adjust = next; - } else { - return; + __vma_set_range(next, vmg->end, next->vm_end); + vma_sub_pgoff(next, delta >> PAGE_SHIFT); } - - vma_set_range(adjust, vmg->end, adjust->vm_end, pgoff); } /*
--
2.54.0