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author | David Herrmann <dh.herrmann@gmail.com> | 2015-09-07 12:05:41 +0200 |
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committer | Marcel Holtmann <marcel@holtmann.org> | 2015-10-21 00:49:23 +0200 |
commit | 660f0fc07d21114549c1862e67e78b1cf0c90c29 (patch) | |
tree | 067f735990ec17c8442019aa1cbe9fa027e22a87 | |
parent | 34cea41e84d5e87a0bd4d5388adab58d0cbc9532 (diff) | |
download | linux-660f0fc07d21114549c1862e67e78b1cf0c90c29.tar.gz linux-660f0fc07d21114549c1862e67e78b1cf0c90c29.tar.bz2 linux-660f0fc07d21114549c1862e67e78b1cf0c90c29.zip |
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>
-rw-r--r-- | net/bluetooth/hidp/core.c | 14 |
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); } |