lkml.org 
[lkml]   [2020]   [Mar]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
Subject[PATCH v2] Bluetooth: clean up connection in hci_cs_disconnect
From
From: Joseph Hwang <josephsih@chromium.org>

In bluetooth core specification 4.2,
Vol 2, Part E, 7.8.9 LE Set Advertise Enable Command, it says

The Controller shall continue advertising until ...
or until a connection is created or ...
In these cases, advertising is then disabled.

Hence, advertising would be disabled before a connection is
established. In current kernel implementation, advertising would
be re-enabled when all connections are terminated.

The correct disconnection flow looks like

< HCI Command: Disconnect

> HCI Event: Command Status
Status: Success

> HCI Event: Disconnect Complete
Status: Success

Specifically, the last Disconnect Complete Event would trigger a
callback function hci_event.c:hci_disconn_complete_evt() to
cleanup the connection and re-enable advertising when proper.

However, sometimes, there might occur an exception in the controller
when disconnection is being executed. The disconnection flow might
then look like

< HCI Command: Disconnect

> HCI Event: Command Status
Status: Unknown Connection Identifier

Note that "> HCI Event: Disconnect Complete" is missing when such an
exception occurs. This would result in advertising staying disabled
forever since the connection in question is not cleaned up correctly.

To fix the controller exception issue, we need to do some connection
cleanup when the disconnect command status indicates an error.

Signed-off-by: Joseph Hwang <josephsih@chromium.org>
Signed-off-by: Manish Mandlik <mmandlik@google.com>
---

Changes in v2:
- Moved "u8 type" declaration inside if block

net/bluetooth/hci_event.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index a40ed31f6eb8f..a116114279107 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -2202,10 +2202,22 @@ static void hci_cs_disconnect(struct hci_dev *hdev, u8 status)
hci_dev_lock(hdev);

conn = hci_conn_hash_lookup_handle(hdev, __le16_to_cpu(cp->handle));
- if (conn)
+ if (conn) {
+ u8 type = conn->type;
+
mgmt_disconnect_failed(hdev, &conn->dst, conn->type,
conn->dst_type, status);

+ /* If the disconnection failed for any reason, the upper layer
+ * does not retry to disconnect in current implementation.
+ * Hence, we need to do some basic cleanup here and re-enable
+ * advertising if necessary.
+ */
+ hci_conn_del(conn);
+ if (type == LE_LINK)
+ hci_req_reenable_advertising(hdev);
+ }
+
hci_dev_unlock(hdev);
}

--
2.25.1.481.gfbce0eb801-goog
\
 
 \ /
  Last update: 2020-03-12 03:20    [W:0.054 / U:4.784 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site