[PATCH] Bluetooth: Make handle of hci_conn be unique

[Ziyang Xuan <william.xuanziyang@xxxxxxxxxx>]

The handle of new hci_conn is always HCI_CONN_HANDLE_MAX + 1 if
the handle of the first hci_conn entry in hci_dev->conn_hash->list
is not HCI_CONN_HANDLE_MAX + 1. Use ida to manage the allocation of
hci_conn->handle to make it be unique.

Fixes: 9f78191cc9f1 ("Bluetooth: hci_conn: Always allocate unique handles")
Signed-off-by: Ziyang Xuan <william.xuanziyang@xxxxxxxxxx>
---
 include/net/bluetooth/hci_core.h |  2 ++
 net/bluetooth/hci_conn.c         | 30 +++++++++++++-----------------
 net/bluetooth/hci_core.c         |  3 +++
 3 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index f36c1fd5d64e..a0c0e12e3a18 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -350,6 +350,8 @@ struct hci_dev {
 	struct list_head list;
 	struct mutex	lock;
 
+	struct ida	unset_handle_ida;
+
 	const char	*name;
 	unsigned long	flags;
 	__u16		id;
diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index 974631e652c1..6ec161bf569a 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -153,6 +153,9 @@ static void hci_conn_cleanup(struct hci_conn *conn)
 
 	hci_conn_hash_del(hdev, conn);
 
+	if (HCI_CONN_HANDLE_UNSET(conn->handle))
+		ida_free(&hdev->unset_handle_ida, conn->handle);
+
 	if (conn->cleanup)
 		conn->cleanup(conn);
 
@@ -929,29 +932,17 @@ static void cis_cleanup(struct hci_conn *conn)
 	hci_le_remove_cig(hdev, conn->iso_qos.ucast.cig);
 }
 
-static u16 hci_conn_hash_alloc_unset(struct hci_dev *hdev)
+static int hci_conn_hash_alloc_unset(struct hci_dev *hdev)
 {
-	struct hci_conn_hash *h = &hdev->conn_hash;
-	struct hci_conn  *c;
-	u16 handle = HCI_CONN_HANDLE_MAX + 1;
-
-	rcu_read_lock();
-
-	list_for_each_entry_rcu(c, &h->list, list) {
-		/* Find the first unused handle */
-		if (handle == 0xffff || c->handle != handle)
-			break;
-		handle++;
-	}
-	rcu_read_unlock();
-
-	return handle;
+	return ida_alloc_range(&hdev->unset_handle_ida, HCI_CONN_HANDLE_MAX + 1,
+			       U16_MAX, GFP_ATOMIC);
 }
 
 struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst,
 			      u8 role)
 {
 	struct hci_conn *conn;
+	int handle;
 
 	BT_DBG("%s dst %pMR", hdev->name, dst);
 
@@ -961,7 +952,12 @@ struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst,
 
 	bacpy(&conn->dst, dst);
 	bacpy(&conn->src, &hdev->bdaddr);
-	conn->handle = hci_conn_hash_alloc_unset(hdev);
+	handle = hci_conn_hash_alloc_unset(hdev);
+	if (unlikely(handle < 0)) {
+		kfree(conn);
+		return NULL;
+	}
+	conn->handle = handle;
 	conn->hdev  = hdev;
 	conn->type  = type;
 	conn->role  = role;
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 195aea2198a9..65601aa52e0d 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -2535,6 +2535,8 @@ struct hci_dev *hci_alloc_dev_priv(int sizeof_priv)
 	mutex_init(&hdev->lock);
 	mutex_init(&hdev->req_lock);
 
+	ida_init(&hdev->unset_handle_ida);
+
 	INIT_LIST_HEAD(&hdev->mesh_pending);
 	INIT_LIST_HEAD(&hdev->mgmt_pending);
 	INIT_LIST_HEAD(&hdev->reject_list);
@@ -2789,6 +2791,7 @@ void hci_release_dev(struct hci_dev *hdev)
 	hci_codec_list_clear(&hdev->local_codecs);
 	hci_dev_unlock(hdev);
 
+	ida_destroy(&hdev->unset_handle_ida);
 	ida_simple_remove(&hci_index_ida, hdev->id);
 	kfree_skb(hdev->sent_cmd);
 	kfree_skb(hdev->recv_event);
-- 
2.25.1