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Commit f35368dd authored by Xiao Guangrong's avatar Xiao Guangrong Committed by Linus Torvalds
Browse files

prio_tree: cleanup prio_tree_left()/prio_tree_right() 



Introduce iter_walk_down()/iter_walk_up() to remove the common code
between prio_tree_left() and prio_tree_right().

Signed-off-by: default avatarXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f42240d7

lib/prio_tree.c

+37 −41
Original line number Diff line number Diff line
@@ -304,6 +304,40 @@ void prio_tree_remove(struct prio_tree_root *root, struct prio_tree_node *node) 
		cur = prio_tree_replace(root, cur->parent, cur);

}



static void iter_walk_down(struct prio_tree_iter *iter)

{

	iter->mask >>= 1;

	if (iter->mask) {

		if (iter->size_level)

			iter->size_level++;

		return;

	}



	if (iter->size_level) {

		BUG_ON(!prio_tree_left_empty(iter->cur));

		BUG_ON(!prio_tree_right_empty(iter->cur));

		iter->size_level++;

		iter->mask = ULONG_MAX;

	} else {

		iter->size_level = 1;

		iter->mask = 1UL << (BITS_PER_LONG - 1);

	}

}



static void iter_walk_up(struct prio_tree_iter *iter)

{

	if (iter->mask == ULONG_MAX)

		iter->mask = 1UL;

	else if (iter->size_level == 1)

		iter->mask = 1UL;

	else

		iter->mask <<= 1;

	if (iter->size_level)

		iter->size_level--;

	if (!iter->size_level && (iter->value & iter->mask))

		iter->value ^= iter->mask;

}



/*

 * Following functions help to enumerate all prio_tree_nodes in the tree that

 * overlap with the input interval X [radix_index, heap_index]. The enumeration
@@ -322,21 +356,7 @@ static struct prio_tree_node *prio_tree_left(struct prio_tree_iter *iter, 


	if (iter->r_index <= *h_index) {

		iter->cur = iter->cur->left;

		iter->mask >>= 1;

		if (iter->mask) {

			if (iter->size_level)

				iter->size_level++;

		} else {

			if (iter->size_level) {

				BUG_ON(!prio_tree_left_empty(iter->cur));

				BUG_ON(!prio_tree_right_empty(iter->cur));

				iter->size_level++;

				iter->mask = ULONG_MAX;

			} else {

				iter->size_level = 1;

				iter->mask = 1UL << (BITS_PER_LONG - 1);

			}

		}

		iter_walk_down(iter);

		return iter->cur;

	}
@@ -363,22 +383,7 @@ static struct prio_tree_node *prio_tree_right(struct prio_tree_iter *iter, 


	if (iter->r_index <= *h_index) {

		iter->cur = iter->cur->right;

		iter->mask >>= 1;

		iter->value = value;

		if (iter->mask) {

			if (iter->size_level)

				iter->size_level++;

		} else {

			if (iter->size_level) {

				BUG_ON(!prio_tree_left_empty(iter->cur));

				BUG_ON(!prio_tree_right_empty(iter->cur));

				iter->size_level++;

				iter->mask = ULONG_MAX;

			} else {

				iter->size_level = 1;

				iter->mask = 1UL << (BITS_PER_LONG - 1);

			}

		}

		iter_walk_down(iter);

		return iter->cur;

	}
@@ -388,16 +393,7 @@ static struct prio_tree_node *prio_tree_right(struct prio_tree_iter *iter, 
static struct prio_tree_node *prio_tree_parent(struct prio_tree_iter *iter)

{

	iter->cur = iter->cur->parent;

	if (iter->mask == ULONG_MAX)

		iter->mask = 1UL;

	else if (iter->size_level == 1)

		iter->mask = 1UL;

	else

		iter->mask <<= 1;

	if (iter->size_level)

		iter->size_level--;

	if (!iter->size_level && (iter->value & iter->mask))

		iter->value ^= iter->mask;

	iter_walk_up(iter);

	return iter->cur;

}