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-rw-r--r--mm/mmap.c36
1 files changed, 8 insertions, 28 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index adea3b8880e3..3f758c7f4c81 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1603,39 +1603,19 @@ struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
1603 1603
1604EXPORT_SYMBOL(find_vma); 1604EXPORT_SYMBOL(find_vma);
1605 1605
1606/* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */ 1606/*
1607 * Same as find_vma, but also return a pointer to the previous VMA in *pprev.
1608 * Note: pprev is set to NULL when return value is NULL.
1609 */
1607struct vm_area_struct * 1610struct vm_area_struct *
1608find_vma_prev(struct mm_struct *mm, unsigned long addr, 1611find_vma_prev(struct mm_struct *mm, unsigned long addr,
1609 struct vm_area_struct **pprev) 1612 struct vm_area_struct **pprev)
1610{ 1613{
1611 struct vm_area_struct *vma = NULL, *prev = NULL; 1614 struct vm_area_struct *vma;
1612 struct rb_node *rb_node;
1613 if (!mm)
1614 goto out;
1615
1616 /* Guard against addr being lower than the first VMA */
1617 vma = mm->mmap;
1618
1619 /* Go through the RB tree quickly. */
1620 rb_node = mm->mm_rb.rb_node;
1621
1622 while (rb_node) {
1623 struct vm_area_struct *vma_tmp;
1624 vma_tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb);
1625
1626 if (addr < vma_tmp->vm_end) {
1627 rb_node = rb_node->rb_left;
1628 } else {
1629 prev = vma_tmp;
1630 if (!prev->vm_next || (addr < prev->vm_next->vm_end))
1631 break;
1632 rb_node = rb_node->rb_right;
1633 }
1634 }
1635 1615
1636out: 1616 vma = find_vma(mm, addr);
1637 *pprev = prev; 1617 *pprev = vma ? vma->vm_prev : NULL;
1638 return prev ? prev->vm_next : vma; 1618 return vma;
1639} 1619}
1640 1620
1641/* 1621/*