mm/mmap: Introduce abort_munmap_vmas()

Extract clean up of failed munmap() operations from
do_vmi_align_munmap().  This simplifies later patches in the series.

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

diff --git a/mm/mmap.c b/mm/mmap.c
index 4a9929bc18bda805a0384836e2ac5c2b8396065e..bcfcbe006b1e2f1b344779839a531bd00d95af5a 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2545,6 +2545,25 @@ struct vm_area_struct *vma_merge_extend(struct vma_iterator *vmi,
                         vma->vm_userfaultfd_ctx, anon_vma_name(vma));
 }
 
+/*
+ * abort_munmap_vmas - Undo any munmap work and free resources
+ *
+ * Reattach detached vmas, free up maple tree used to track the vmas.
+ */
+static inline void abort_munmap_vmas(struct ma_state *mas_detach)
+{
+       struct vm_area_struct *vma;
+       int limit;
+
+       limit = mas_detach->index;
+       mas_set(mas_detach, 0);
+       /* Re-attach any detached VMAs */
+       mas_for_each(mas_detach, vma, limit)
+               vma_mark_detached(vma, false);
+
+       __mt_destroy(mas_detach->tree);
+}
+
 /*
  * do_vmi_align_munmap() - munmap the aligned region from @start to @end.
  * @vmi: The vma iterator
@@ -2699,11 +2718,7 @@ clear_tree_failed:
 userfaultfd_error:
 munmap_gather_failed:
 end_split_failed:
-       mas_set(&mas_detach, 0);
-       mas_for_each(&mas_detach, next, end)
-               vma_mark_detached(next, false);
-
-       __mt_destroy(&mt_detach);
+       abort_munmap_vmas(&mas_detach);
 start_split_failed:
 map_count_exceeded:
        validate_mm(mm);