From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
Extract all necessary operations that need to be completed after the vma
maple tree is updated from a munmap() operation. Extracting this makes
the later patch in the series easier to understand.
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
Reviewed-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
---
mm/vma.c | 80 ++++++++++++++++++++++++++++++++++++++------------------
1 file changed, 55 insertions(+), 25 deletions(-)
diff --git a/mm/vma.c b/mm/vma.c
index 58ecd447670d..3a2098464b8f 100644
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -684,6 +684,58 @@ static inline void abort_munmap_vmas(struct ma_state *mas_detach)
__mt_destroy(mas_detach->tree);
}
+/*
+ * vmi_complete_munmap_vmas() - Finish the munmap() operation
+ * @vmi: The vma iterator
+ * @vma: The first vma to be munmapped
+ * @mm: The mm struct
+ * @start: The start address
+ * @end: The end address
+ * @unlock: Unlock the mm or not
+ * @mas_detach: them maple state of the detached vma maple tree
+ * @locked_vm: The locked_vm count in the detached vmas
+ *
+ * This function updates the mm_struct, unmaps the region, frees the resources
+ * used for the munmap() and may downgrade the lock - if requested. Everything
+ * needed to be done once the vma maple tree is updated.
+ */
+static void
+vmi_complete_munmap_vmas(struct vma_iterator *vmi, struct vm_area_struct *vma,
+ struct mm_struct *mm, unsigned long start, unsigned long end,
+ bool unlock, struct ma_state *mas_detach,
+ unsigned long locked_vm)
+{
+ struct vm_area_struct *prev, *next;
+ int count;
+
+ count = mas_detach->index + 1;
+ mm->map_count -= count;
+ mm->locked_vm -= locked_vm;
+ if (unlock)
+ mmap_write_downgrade(mm);
+
+ prev = vma_iter_prev_range(vmi);
+ next = vma_next(vmi);
+ if (next)
+ vma_iter_prev_range(vmi);
+
+ /*
+ * We can free page tables without write-locking mmap_lock because VMAs
+ * were isolated before we downgraded mmap_lock.
+ */
+ mas_set(mas_detach, 1);
+ unmap_region(mm, mas_detach, vma, prev, next, start, end, count,
+ !unlock);
+ /* Statistics and freeing VMAs */
+ mas_set(mas_detach, 0);
+ remove_mt(mm, mas_detach);
+ validate_mm(mm);
+ if (unlock)
+ mmap_read_unlock(mm);
+
+ __mt_destroy(mas_detach->tree);
+}
+
/*
* do_vmi_align_munmap() - munmap the aligned region from @start to @end.
* @vmi: The vma iterator
@@ -703,7 +755,7 @@ do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
struct mm_struct *mm, unsigned long start,
unsigned long end, struct list_head *uf, bool unlock)
{
- struct vm_area_struct *prev, *next = NULL;
+ struct vm_area_struct *next = NULL;
struct maple_tree mt_detach;
int count = 0;
int error = -ENOMEM;
@@ -818,31 +870,9 @@ do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
goto clear_tree_failed;
/* Point of no return */
- mm->locked_vm -= locked_vm;
- mm->map_count -= count;
- if (unlock)
- mmap_write_downgrade(mm);
-
- prev = vma_iter_prev_range(vmi);
- next = vma_next(vmi);
- if (next)
- vma_iter_prev_range(vmi);
-
- /*
- * We can free page tables without write-locking mmap_lock because VMAs
- * were isolated before we downgraded mmap_lock.
- */
- mas_set(&mas_detach, 1);
- unmap_region(mm, &mas_detach, vma, prev, next, start, end, count,
- !unlock);
- /* Statistics and freeing VMAs */
- mas_set(&mas_detach, 0);
- remove_mt(mm, &mas_detach);
- validate_mm(mm);
- if (unlock)
- mmap_read_unlock(mm);
+ vmi_complete_munmap_vmas(vmi, vma, mm, start, end, unlock, &mas_detach,
+ locked_vm);
- __mt_destroy(&mt_detach);
return 0;
modify_vma_failed:
--
2.43.0
