ARM: OMAP3+: SmartReflex: fix err interrupt disable sequence

[~andy/linux] / mm / mmap.c

diff --git a/mm/mmap.c b/mm/mmap.c
index eae90af60ea62e066defeab345e5079f57a80dc2..3f758c7f4c815c2b0edf494526b2823b41fbc142 100644 (file)
--- 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)
 
 EXPORT_SYMBOL(find_vma);
 
-/* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */
+/*
+ * Same as find_vma, but also return a pointer to the previous VMA in *pprev.
+ * Note: pprev is set to NULL when return value is NULL.
+ */
 struct vm_area_struct *
 find_vma_prev(struct mm_struct *mm, unsigned long addr,
                        struct vm_area_struct **pprev)
 {
-       struct vm_area_struct *vma = NULL, *prev = NULL;
-       struct rb_node *rb_node;
-       if (!mm)
-               goto out;
-
-       /* Guard against addr being lower than the first VMA */
-       vma = mm->mmap;
-
-       /* Go through the RB tree quickly. */
-       rb_node = mm->mm_rb.rb_node;
-
-       while (rb_node) {
-               struct vm_area_struct *vma_tmp;
-               vma_tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb);
-
-               if (addr < vma_tmp->vm_end) {
-                       rb_node = rb_node->rb_left;
-               } else {
-                       prev = vma_tmp;
-                       if (!prev->vm_next || (addr < prev->vm_next->vm_end))
-                               break;
-                       rb_node = rb_node->rb_right;
-               }
-       }
+       struct vm_area_struct *vma;
 
-out:
-       *pprev = prev;
-       return prev ? prev->vm_next : vma;
+       vma = find_vma(mm, addr);
+       *pprev = vma ? vma->vm_prev : NULL;
+       return vma;
 }
 
 /*
@@ -2322,13 +2302,16 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
        struct vm_area_struct *new_vma, *prev;
        struct rb_node **rb_link, *rb_parent;
        struct mempolicy *pol;
+       bool faulted_in_anon_vma = true;
 
        /*
         * If anonymous vma has not yet been faulted, update new pgoff
         * to match new location, to increase its chance of merging.
         */
-       if (!vma->vm_file && !vma->anon_vma)
+       if (unlikely(!vma->vm_file && !vma->anon_vma)) {
                pgoff = addr >> PAGE_SHIFT;
+               faulted_in_anon_vma = false;
+       }
 
        find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
        new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
@@ -2337,9 +2320,24 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
                /*
                 * Source vma may have been merged into new_vma
                 */
-               if (vma_start >= new_vma->vm_start &&
-                   vma_start < new_vma->vm_end)
+               if (unlikely(vma_start >= new_vma->vm_start &&
+                            vma_start < new_vma->vm_end)) {
+                       /*
+                        * The only way we can get a vma_merge with
+                        * self during an mremap is if the vma hasn't
+                        * been faulted in yet and we were allowed to
+                        * reset the dst vma->vm_pgoff to the
+                        * destination address of the mremap to allow
+                        * the merge to happen. mremap must change the
+                        * vm_pgoff linearity between src and dst vmas
+                        * (in turn preventing a vma_merge) to be
+                        * safe. It is only safe to keep the vm_pgoff
+                        * linear if there are no pages mapped yet.
+                        */
+                       VM_BUG_ON(faulted_in_anon_vma);
                        *vmap = new_vma;
+               } else
+                       anon_vma_moveto_tail(new_vma);
        } else {
                new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
                if (new_vma) {