mm/mmap: Change find_vma_prev() to use maple tree

Change the implementation of find_vma_prev to use the new maple tree
data structure.

Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>

diff --git a/mm/mmap.c b/mm/mmap.c
index f176ca337415f4b9142b72eef3119c85c27a04c7..baab0bac74c7ccd57518f184e723c2804d8879ec 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2525,23 +2525,30 @@ struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
 }
 EXPORT_SYMBOL(find_vma);
 
-/*
- * Same as find_vma, but also return a pointer to the previous VMA in *pprev.
+/**
+ * find_vma_prev() - Find the VMA for a given address, or the next vma and
+ * set %pprev to the previous VMA, if any.
+ * @mm: The mm_struct to check
+ * @addr: The address
+ * @pprev: The pointer to set to the previous VMA
+ *
+ * Returns: The VMA associated with @addr, or the next vma.
+ * May return %NULL in the case of no vma at addr or above.
  */
 struct vm_area_struct *
 find_vma_prev(struct mm_struct *mm, unsigned long addr,
-                       struct vm_area_struct **pprev)
+             struct vm_area_struct **pprev)
 {
        struct vm_area_struct *vma;
+       MA_STATE(mas, &mm->mm_mt, addr, addr);
 
-       vma = find_vma(mm, addr);
-       if (vma) {
-               *pprev = vma->vm_prev;
-       } else {
-               struct rb_node *rb_node = rb_last(&mm->mm_rb);
+       rcu_read_lock();
+       vma = mas_find(&mas, ULONG_MAX);
+       if (!vma)
+               mas_reset(&mas);
 
-               *pprev = rb_node ? rb_entry(rb_node, struct vm_area_struct, vm_rb) : NULL;
-       }
+       *pprev = mas_prev(&mas, 0);
+       rcu_read_unlock();
        return vma;
 }