mm: expand vma iterator interface

Add wrappers for the maple tree to the vma iterator.  This will provide
type safety at compile time.

Link: https://lkml.kernel.org/r/20230120162650.984577-8-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

2 files changed, 43 insertions, 7 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index c9db257f09b3..b977a90d9829 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -670,16 +670,16 @@ static inline bool vma_is_accessible(struct vm_area_struct *vma)
 static inline
 struct vm_area_struct *vma_find(struct vma_iterator *vmi, unsigned long max)
 {
-	return mas_find(&vmi->mas, max);
+	return mas_find(&vmi->mas, max - 1);
 }
 
 static inline struct vm_area_struct *vma_next(struct vma_iterator *vmi)
 {
 	/*
-	 * Uses vma_find() to get the first VMA when the iterator starts.
+	 * Uses mas_find() to get the first VMA when the iterator starts.
 	 * Calling mas_next() could skip the first entry.
 	 */
-	return vma_find(vmi, ULONG_MAX);
+	return mas_find(&vmi->mas, ULONG_MAX);
 }
 
 static inline struct vm_area_struct *vma_prev(struct vma_iterator *vmi)
@@ -692,12 +692,50 @@ static inline unsigned long vma_iter_addr(struct vma_iterator *vmi)
 	return vmi->mas.index;
 }
 
+static inline unsigned long vma_iter_end(struct vma_iterator *vmi)
+{
+	return vmi->mas.last + 1;
+}
+static inline int vma_iter_bulk_alloc(struct vma_iterator *vmi,
+				      unsigned long count)
+{
+	return mas_expected_entries(&vmi->mas, count);
+}
+
+/* Free any unused preallocations */
+static inline void vma_iter_free(struct vma_iterator *vmi)
+{
+	mas_destroy(&vmi->mas);
+}
+
+static inline int vma_iter_bulk_store(struct vma_iterator *vmi,
+				      struct vm_area_struct *vma)
+{
+	vmi->mas.index = vma->vm_start;
+	vmi->mas.last = vma->vm_end - 1;
+	mas_store(&vmi->mas, vma);
+	if (unlikely(mas_is_err(&vmi->mas)))
+		return -ENOMEM;
+
+	return 0;
+}
+
+static inline void vma_iter_invalidate(struct vma_iterator *vmi)
+{
+	mas_pause(&vmi->mas);
+}
+
+static inline void vma_iter_set(struct vma_iterator *vmi, unsigned long addr)
+{
+	mas_set(&vmi->mas, addr);
+}
+
 #define for_each_vma(__vmi, __vma)					\
 	while (((__vma) = vma_next(&(__vmi))) != NULL)
 
 /* The MM code likes to work with exclusive end addresses */
 #define for_each_vma_range(__vmi, __vma, __end)				\
-	while (((__vma) = vma_find(&(__vmi), (__end) - 1)) != NULL)
+	while (((__vma) = vma_find(&(__vmi), (__end))) != NULL)
 
 #ifdef CONFIG_SHMEM
 /*
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 452920467223..5ca11c6c46e8 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -849,9 +849,7 @@ struct vma_iterator {
 static inline void vma_iter_init(struct vma_iterator *vmi,
 		struct mm_struct *mm, unsigned long addr)
 {
-	vmi->mas.tree = &mm->mm_mt;
-	vmi->mas.index = addr;
-	vmi->mas.node = MAS_START;
+	mas_init(&vmi->mas, &mm->mm_mt, addr);
 }
 
 struct mmu_gather;