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authorDavid Herrmann <dh.herrmann@gmail.com>2015-09-07 13:05:41 +0300
committerMarcel Holtmann <marcel@holtmann.org>2015-10-21 01:49:23 +0300
commit660f0fc07d21114549c1862e67e78b1cf0c90c29 (patch)
tree067f735990ec17c8442019aa1cbe9fa027e22a87 /net/bluetooth/hidp
parent34cea41e84d5e87a0bd4d5388adab58d0cbc9532 (diff)
downloadlinux-660f0fc07d21114549c1862e67e78b1cf0c90c29.tar.xz
Bluetooth: hidp: fix device disconnect on idle timeout
The HIDP specs define an idle-timeout which automatically disconnects a device. This has always been implemented in the HIDP layer and forced a synchronous shutdown of the hidp-scheduler. This works just fine, but lacks a forced disconnect on the underlying l2cap channels. This has been broken since: commit 5205185d461d5902325e457ca80bd421127b7308 Author: David Herrmann <dh.herrmann@gmail.com> Date: Sat Apr 6 20:28:47 2013 +0200 Bluetooth: hidp: remove old session-management The old session-management always forced an l2cap error on the ctrl/intr channels when shutting down. The new session-management skips this, as we don't want to enforce channel policy on the caller. In other words, if user-space removes an HIDP device, the underlying channels (which are *owned* and *referenced* by user-space) are still left active. User-space needs to call shutdown(2) or close(2) to release them. Unfortunately, this does not work with idle-timeouts. There is no way to signal user-space that the HIDP layer has been stopped. The API simply does not support any event-passing except for poll(2). Hence, we restore old behavior and force EUNATCH on the sockets if the HIDP layer is disconnected due to idle-timeouts (behavior of explicit disconnects remains unmodified). User-space can still call getsockopt(..., SO_ERROR, ...) ..to retrieve the EUNATCH error and clear sk_err. Hence, the channels can still be re-used (which nobody does so far, though). Therefore, the API still supports the new behavior, but with this patch it's also compatible to the old implicit channel shutdown. Cc: <stable@vger.kernel.org> # 3.10+ Reported-by: Mark Haun <haunma@keteu.org> Reported-by: Luiz Augusto von Dentz <luiz.dentz@gmail.com> Signed-off-by: David Herrmann <dh.herrmann@gmail.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Diffstat (limited to 'net/bluetooth/hidp')
-rw-r--r--net/bluetooth/hidp/core.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c
index f1a117f8cad2..0bec4588c3c8 100644
--- a/net/bluetooth/hidp/core.c
+++ b/net/bluetooth/hidp/core.c
@@ -401,6 +401,20 @@ static void hidp_idle_timeout(unsigned long arg)
{
struct hidp_session *session = (struct hidp_session *) arg;
+ /* The HIDP user-space API only contains calls to add and remove
+ * devices. There is no way to forward events of any kind. Therefore,
+ * we have to forcefully disconnect a device on idle-timeouts. This is
+ * unfortunate and weird API design, but it is spec-compliant and
+ * required for backwards-compatibility. Hence, on idle-timeout, we
+ * signal driver-detach events, so poll() will be woken up with an
+ * error-condition on both sockets.
+ */
+
+ session->intr_sock->sk->sk_err = EUNATCH;
+ session->ctrl_sock->sk->sk_err = EUNATCH;
+ wake_up_interruptible(sk_sleep(session->intr_sock->sk));
+ wake_up_interruptible(sk_sleep(session->ctrl_sock->sk));
+
hidp_session_terminate(session);
}