mm/mmap: convert all mas except mas_detach to vma iterator

There are two types of iterators mas and vmi in the current code.  If the
maple tree comes from the mm structure, we can use the vma iterator. 
Avoid using mas directly as possible.

Keep using mas for the mt_detach tree, since it doesn't come from the mm
structure.

Remove as many uses of mas as possible, but we will still have a few that
must be passed through in unmap_vmas() and free_pgtables().

Also introduce vma_iter_reset, vma_iter_{prev, next}_range_limit and
vma_iter_area_{lowest, highest} helper functions for using the vma
interator.

Link: https://lkml.kernel.org/r/20240325063258.1437618-1-yajun.deng@linux.devSigned-off-by: Yajun Deng <yajun.deng@linux.dev>
Tested-by: Helge Deller <deller@gmx.de>	[parisc]
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/internal.h

@@ -1254,6 +1254,35 @@ static inline void vma_iter_config(struct vma_iterator *vmi,
 	__mas_set_range(&vmi->mas, index, last - 1);
 }
 
+static inline void vma_iter_reset(struct vma_iterator *vmi)
+{
+	mas_reset(&vmi->mas);
+}
+
+static inline
+struct vm_area_struct *vma_iter_prev_range_limit(struct vma_iterator *vmi, unsigned long min)
+{
+	return mas_prev_range(&vmi->mas, min);
+}
+
+static inline
+struct vm_area_struct *vma_iter_next_range_limit(struct vma_iterator *vmi, unsigned long max)
+{
+	return mas_next_range(&vmi->mas, max);
+}
+
+static inline int vma_iter_area_lowest(struct vma_iterator *vmi, unsigned long min,
+				       unsigned long max, unsigned long size)
+{
+	return mas_empty_area(&vmi->mas, min, max - 1, size);
+}
+
+static inline int vma_iter_area_highest(struct vma_iterator *vmi, unsigned long min,
+					unsigned long max, unsigned long size)
+{
+	return mas_empty_area_rev(&vmi->mas, min, max - 1, size);
+}
+
 /*
  * VMA Iterator functions shared between nommu and mmap
  */