[PATCH v2 03/10] net: qrtr: support identical node ids

[Mihai Moldovan <ionic@ionic.de>]

From: Denis Kenzior <denkenz@gmail.com>

Add support for tracking multiple endpoints that may have conflicting
node identifiers. This is achieved by using both the node and endpoint
identifiers as the key inside the radix_tree data structure.

For backward compatibility with existing clients, the previous key
schema (node identifier only) is preserved. However, this schema will
only support the first endpoint/node combination.  This is acceptable
for legacy clients as support for multiple endpoints with conflicting
node identifiers was not previously possible.

Signed-off-by: Denis Kenzior <denkenz@gmail.com>
Reviewed-by: Marcel Holtmann <marcel@holtmann.org>
Reviewed-by: Andy Gross <agross@kernel.org>
Signed-off-by: Mihai Moldovan <ionic@ionic.de>

---

v2:
  - rebase against current master
  - no action on review comment regarding integer overflow on 32 bit
    long platforms (thus far)
---
 net/qrtr/af_qrtr.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/net/qrtr/af_qrtr.c b/net/qrtr/af_qrtr.c
index be275871fb2a..e83d491a8da9 100644
--- a/net/qrtr/af_qrtr.c
+++ b/net/qrtr/af_qrtr.c
@@ -418,12 +418,20 @@ static struct qrtr_node *qrtr_node_lookup(unsigned int nid)
 static void qrtr_node_assign(struct qrtr_node *node, unsigned int nid)
 {
 	unsigned long flags;
+	unsigned long key;
 
 	if (nid == QRTR_EP_NID_AUTO)
 		return;
 
 	spin_lock_irqsave(&qrtr_nodes_lock, flags);
-	radix_tree_insert(&qrtr_nodes, nid, node);
+
+	/* Always insert with the endpoint_id + node_id */
+	key = (unsigned long)node->ep->id << 32 | nid;
+	radix_tree_insert(&qrtr_nodes, key, node);
+
+	if (!radix_tree_lookup(&qrtr_nodes, nid))
+		radix_tree_insert(&qrtr_nodes, nid, node);
+
 	if (node->nid == QRTR_EP_NID_AUTO)
 		node->nid = nid;
 	spin_unlock_irqrestore(&qrtr_nodes_lock, flags);
-- 
2.50.0