commit 1785dbf9e30be62ab45e34900e574b8307bc98b5
author Peter Hurley <peter@hurleysoftware.com> Tue Aug 30 11:53:35 2011 -0400
committer Gustavo F. Padovan <padovan@profusion.mobi> Fri Oct 07 01:43:10 2011 -0300
tree 0f5c033aeb98f1b1ff4c1285798244b9093a4b5a
parent ab88f7149e0e3284623adcaa60460a9a69d9f131

Bluetooth: hidp: safely acquire hci connection

Claim device lock to safely enumerate hci connection list and bump
hci connection proxy device ref count simultaneously.

This patch incorporates David Herrmann's fix to prevent adding an
HID device when the hci connection no longer exists.

Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>

net/bluetooth/hidp/core.c

diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c
index f2bec49..304a73f 100644
--- a/net/bluetooth/hidp/core.c
+++ b/net/bluetooth/hidp/core.c
@@ -95,8 +95,6 @@
 {
 	__module_get(THIS_MODULE);
 	list_add(&session->list, &hidp_session_list);
-
-	hci_conn_hold_device(session->conn);
 }
 
 static void __hidp_unlink_session(struct hidp_session *session)
@@ -785,24 +783,26 @@
 	return 0;
 }
 
-static struct device *hidp_get_device(struct hidp_session *session)
+static struct hci_conn *hidp_find_connection(struct hidp_session *session)
 {
 	bdaddr_t *src = &bt_sk(session->ctrl_sock->sk)->src;
 	bdaddr_t *dst = &bt_sk(session->ctrl_sock->sk)->dst;
-	struct device *device = NULL;
+	struct hci_conn *conn;
 	struct hci_dev *hdev;
 
 	hdev = hci_get_route(dst, src);
 	if (!hdev)
 		return NULL;
 
-	session->conn = hci_conn_hash_lookup_ba(hdev, ACL_LINK, dst);
-	if (session->conn)
-		device = &session->conn->dev;
+	hci_dev_lock_bh(hdev);
+	conn = hci_conn_hash_lookup_ba(hdev, ACL_LINK, dst);
+	if (conn)
+		hci_conn_hold_device(conn);
+	hci_dev_unlock_bh(hdev);
 
 	hci_dev_put(hdev);
 
-	return device;
+	return conn;
 }
 
 static int hidp_setup_input(struct hidp_session *session,
@@ -852,7 +852,7 @@
 		input->relbit[0] |= BIT_MASK(REL_WHEEL);
 	}
 
-	input->dev.parent = hidp_get_device(session);
+	input->dev.parent = &session->conn->dev;
 
 	input->event = hidp_input_event;
 
@@ -952,7 +952,7 @@
 	strncpy(hid->phys, batostr(&bt_sk(session->ctrl_sock->sk)->src), 64);
 	strncpy(hid->uniq, batostr(&bt_sk(session->ctrl_sock->sk)->dst), 64);
 
-	hid->dev.parent = hidp_get_device(session);
+	hid->dev.parent = &session->conn->dev;
 	hid->ll_driver = &hidp_hid_driver;
 
 	hid->hid_get_raw_report = hidp_get_raw_report;
@@ -993,6 +993,12 @@
 		goto failed;
 	}
 
+	session->conn = hidp_find_connection(session);
+	if (!session->conn) {
+		err = -ENOTCONN;
+		goto failed;
+	}
+
 	bacpy(&session->bdaddr, &bt_sk(ctrl_sock->sk)->dst);
 
 	session->ctrl_mtu = min_t(uint, l2cap_pi(ctrl_sock->sk)->chan->omtu,
@@ -1018,6 +1024,8 @@
 	session->flags   = req->flags & (1 << HIDP_BLUETOOTH_VENDOR_ID);
 	session->idle_to = req->idle_to;
 
+	__hidp_link_session(session);
+
 	if (req->rd_size > 0) {
 		err = hidp_setup_hid(session, req);
 		if (err)
@@ -1030,8 +1038,6 @@
 			goto purge;
 	}
 
-	__hidp_link_session(session);
-
 	hidp_set_timer(session);
 
 	if (session->hid) {
@@ -1084,8 +1090,6 @@
 unlink:
 	hidp_del_timer(session);
 
-	__hidp_unlink_session(session);
-
 	if (session->input) {
 		input_unregister_device(session->input);
 		session->input = NULL;
@@ -1100,6 +1104,8 @@
 	session->rd_data = NULL;
 
 purge:
+	__hidp_unlink_session(session);
+
 	skb_queue_purge(&session->ctrl_transmit);
 	skb_queue_purge(&session->intr_transmit);