[PATCH 10/20] staging: lustre: ldlm: restore interval_iterate_reverse function

From: James Simmons
Date: Wed Jul 26 2017 - 11:23:01 EST


Earlier the function interval_iterate_reverse function was
removed since it wasn't used by anyone. Now it is being
restored since it will be used by a future patch.

Signed-off-by: James Simmons <jsimmons@xxxxxxxxxxxxx>
---
.../staging/lustre/lustre/include/interval_tree.h | 4 +++
drivers/staging/lustre/lustre/ldlm/interval_tree.c | 40 ++++++++++++++++++++++
2 files changed, 44 insertions(+)

diff --git a/drivers/staging/lustre/lustre/include/interval_tree.h b/drivers/staging/lustre/lustre/include/interval_tree.h
index 0d4f92e..a4d7280 100644
--- a/drivers/staging/lustre/lustre/include/interval_tree.h
+++ b/drivers/staging/lustre/lustre/include/interval_tree.h
@@ -111,4 +111,8 @@ enum interval_iter interval_search(struct interval_node *root,
struct interval_node_extent *ex,
interval_callback_t func, void *data);

+enum interval_iter interval_iterate_reverse(struct interval_node *root,
+ interval_callback_t func,
+ void *data);
+
#endif
diff --git a/drivers/staging/lustre/lustre/ldlm/interval_tree.c b/drivers/staging/lustre/lustre/ldlm/interval_tree.c
index e106902..5bebd9a 100644
--- a/drivers/staging/lustre/lustre/ldlm/interval_tree.c
+++ b/drivers/staging/lustre/lustre/ldlm/interval_tree.c
@@ -110,6 +110,15 @@ static struct interval_node *interval_first(struct interval_node *node)
return node;
}

+static struct interval_node *interval_last(struct interval_node *node)
+{
+ if (!node)
+ return NULL;
+ while (node->in_right)
+ node = node->in_right;
+ return node;
+}
+
static struct interval_node *interval_next(struct interval_node *node)
{
if (!node)
@@ -121,6 +130,37 @@ static struct interval_node *interval_next(struct interval_node *node)
return node->in_parent;
}

+static struct interval_node *interval_prev(struct interval_node *node)
+{
+ if (!node)
+ return NULL;
+
+ if (node->in_left)
+ return interval_last(node->in_left);
+
+ while (node->in_parent && node_is_left_child(node))
+ node = node->in_parent;
+
+ return node->in_parent;
+}
+
+enum interval_iter interval_iterate_reverse(struct interval_node *root,
+ interval_callback_t func,
+ void *data)
+{
+ enum interval_iter rc = INTERVAL_ITER_CONT;
+ struct interval_node *node;
+
+ for (node = interval_last(root); node; node = interval_prev(node)) {
+ rc = func(node, data);
+ if (rc == INTERVAL_ITER_STOP)
+ break;
+ }
+
+ return rc;
+}
+EXPORT_SYMBOL(interval_iterate_reverse);
+
static void __rotate_change_maxhigh(struct interval_node *node,
struct interval_node *rotate)
{
--
1.8.3.1