Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 60670b80 authored by Michel Lespinasse's avatar Michel Lespinasse Committed by Linus Torvalds
Browse files

rbtree: place easiest case first in rb_erase() 



In rb_erase, move the easy case (node to erase has no more than
1 child) first. I feel the code reads easier that way.

Signed-off-by: default avatarMichel Lespinasse <walken@google.com>
Reviewed-by: default avatarRik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7abc704a

lib/rbtree.c

+18 −17
Original line number Original line Diff line number Diff line
@@ -368,17 +368,28 @@ static void __rb_erase_color(struct rb_node *node, struct rb_node *parent, 




void rb_erase(struct rb_node *node, struct rb_root *root)

void rb_erase(struct rb_node *node, struct rb_root *root)

{

{

	struct rb_node *child, *parent;

	struct rb_node *child = node->rb_right, *tmp = node->rb_left;

	struct rb_node *parent;

	int color;

	int color;





	if (!node->rb_left)

	if (!tmp) {

		child = node->rb_right;

	case1:

	else if (!node->rb_right)

		/* Case 1: node to erase has no more than 1 child (easy!) */

		child = node->rb_left;



	else {

		parent = rb_parent(node);

		color = rb_color(node);



		if (child)

			rb_set_parent(child, parent);

		__rb_change_child(node, child, parent, root);

	} else if (!child) {

		/* Still case 1, but this time the child is node->rb_left */

		child = tmp;

		goto case1;

	} else {

		struct rb_node *old = node, *left;

		struct rb_node *old = node, *left;





		node = node->rb_right;

		node = child;

		while ((left = node->rb_left) != NULL)

		while ((left = node->rb_left) != NULL)

			node = left;

			node = left;
@@ -402,18 +413,8 @@ void rb_erase(struct rb_node *node, struct rb_root *root) 
		node->__rb_parent_color = old->__rb_parent_color;

		node->__rb_parent_color = old->__rb_parent_color;

		node->rb_left = old->rb_left;

		node->rb_left = old->rb_left;

		rb_set_parent(old->rb_left, node);

		rb_set_parent(old->rb_left, node);



		goto color;

	}

	}





	parent = rb_parent(node);

	color = rb_color(node);



	if (child)

		rb_set_parent(child, parent);

	__rb_change_child(node, child, parent, root);



color:

	if (color == RB_BLACK)

	if (color == RB_BLACK)

		__rb_erase_color(child, parent, root);

		__rb_erase_color(child, parent, root);

}

}