mm/vma: Introduce vmi_complete_munmap_vmas()

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@oracle.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>

diff --git a/mm/vma.c b/mm/vma.c
index 58ecd447670d725f039becfb4921e8b52baf14cb..3a2098464b8f6af66354add1561cd4fcf15e5b67 100644 (file)
--- 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: