diff options
author | David Herrmann <dh.herrmann@gmail.com> | 2013-04-06 20:28:39 +0200 |
---|---|---|
committer | Gustavo Padovan <gustavo.padovan@collabora.co.uk> | 2013-04-17 02:45:22 -0300 |
commit | 8d12356f33f819ec0d064e233f7ca8e59eaa38ef (patch) | |
tree | b976b1efc17d3f9d207212253d6cb5167c6b755c /net/bluetooth/hci_sysfs.c | |
parent | fc225c3f5d1b6aa6f99c5c300af4605e4923ce79 (diff) |
Bluetooth: introduce hci_conn ref-counting
We currently do not allow using hci_conn from outside of HCI-core.
However, several other users could make great use of it. This includes
HIDP, rfcomm and all other sub-protocols that rely on an active
connection.
Hence, we now introduce hci_conn ref-counting. We currently never call
get_device(). put_device() is exclusively used in hci_conn_del_sysfs().
Hence, we currently never have a greater device-refcnt than 1.
Therefore, it is safe to move the put_device() call from
hci_conn_del_sysfs() to hci_conn_del() (it's the only caller). In fact,
this even fixes a "use-after-free" bug as we access hci_conn after calling
hci_conn_del_sysfs() in hci_conn_del().
From now on we can add references to hci_conn objects in other layers
(like l2cap_sock, HIDP, rfcomm, ...) and grab a reference via
hci_conn_get(). This does _not_ guarantee, that the connection is still
alive. But, this isn't what we want. We can simply lock the hci_conn
device and use "device_is_registered(hci_conn->dev)" to test that.
However, this is hardly necessary as outside users should never rely on
the HCI connection to be alive, anyway. Instead, they should solely rely
on the device-object to be available.
But if sub-devices want the hci_conn object as sysfs parent, they need to
be notified when the connection drops. This will be introduced in later
patches with l2cap_users.
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Diffstat (limited to 'net/bluetooth/hci_sysfs.c')
-rw-r--r-- | net/bluetooth/hci_sysfs.c | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/net/bluetooth/hci_sysfs.c b/net/bluetooth/hci_sysfs.c index ff38561385de..6fe15c822847 100644 --- a/net/bluetooth/hci_sysfs.c +++ b/net/bluetooth/hci_sysfs.c @@ -146,7 +146,6 @@ void hci_conn_del_sysfs(struct hci_conn *conn) } device_del(&conn->dev); - put_device(&conn->dev); hci_dev_put(hdev); } |