mm: replace vma->sharead.linear with vma->shared

After removing vma->shared.nonlinear we have only one member of
vma->shared union, which doesn't make much sense.

This patch drops the union and move struct vma->shared.linear to
vma->shared.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/mm_types.h

@@ -275,11 +275,9 @@ struct vm_area_struct {
 	 * For areas with an address space and backing store,
 	 * linkage into the address_space->i_mmap interval tree.
 	 */
-	union {
-		struct {
-			struct rb_node rb;
-			unsigned long rb_subtree_last;
-		} linear;
+	struct {
+		struct rb_node rb;
+		unsigned long rb_subtree_last;
 	} shared;
 
 	/*

mm/interval_tree.c

@@ -21,8 +21,8 @@ static inline unsigned long vma_last_pgoff(struct vm_area_struct *v)
 	return v->vm_pgoff + ((v->vm_end - v->vm_start) >> PAGE_SHIFT) - 1;
 }
 
-INTERVAL_TREE_DEFINE(struct vm_area_struct, shared.linear.rb,
-		     unsigned long, shared.linear.rb_subtree_last,
+INTERVAL_TREE_DEFINE(struct vm_area_struct, shared.rb,
+		     unsigned long, shared.rb_subtree_last,
 		     vma_start_pgoff, vma_last_pgoff,, vma_interval_tree)
 
 /* Insert node immediately after prev in the interval tree */
@@ -36,26 +36,26 @@ void vma_interval_tree_insert_after(struct vm_area_struct *node,
 
 	VM_BUG_ON_VMA(vma_start_pgoff(node) != vma_start_pgoff(prev), node);
 
-	if (!prev->shared.linear.rb.rb_right) {
+	if (!prev->shared.rb.rb_right) {
 		parent = prev;
-		link = &prev->shared.linear.rb.rb_right;
+		link = &prev->shared.rb.rb_right;
 	} else {
-		parent = rb_entry(prev->shared.linear.rb.rb_right,
-				  struct vm_area_struct, shared.linear.rb);
-		if (parent->shared.linear.rb_subtree_last < last)
-			parent->shared.linear.rb_subtree_last = last;
-		while (parent->shared.linear.rb.rb_left) {
-			parent = rb_entry(parent->shared.linear.rb.rb_left,
-				struct vm_area_struct, shared.linear.rb);
-			if (parent->shared.linear.rb_subtree_last < last)
-				parent->shared.linear.rb_subtree_last = last;
+		parent = rb_entry(prev->shared.rb.rb_right,
+				  struct vm_area_struct, shared.rb);
+		if (parent->shared.rb_subtree_last < last)
+			parent->shared.rb_subtree_last = last;
+		while (parent->shared.rb.rb_left) {
+			parent = rb_entry(parent->shared.rb.rb_left,
+				struct vm_area_struct, shared.rb);
+			if (parent->shared.rb_subtree_last < last)
+				parent->shared.rb_subtree_last = last;
 		}
-		link = &parent->shared.linear.rb.rb_left;
+		link = &parent->shared.rb.rb_left;
 	}
 
-	node->shared.linear.rb_subtree_last = last;
-	rb_link_node(&node->shared.linear.rb, &parent->shared.linear.rb, link);
-	rb_insert_augmented(&node->shared.linear.rb, root,
+	node->shared.rb_subtree_last = last;
+	rb_link_node(&node->shared.rb, &parent->shared.rb, link);
+	rb_insert_augmented(&node->shared.rb, root,
 			    &vma_interval_tree_augment);
 }