From: Archie Pusaka <apusaka@google.com>
To: linux-bluetooth <linux-bluetooth@vger.kernel.org>,
Luiz Augusto von Dentz <luiz.dentz@gmail.com>,
Marcel Holtmann <marcel@holtmann.org>
Cc: Archie Pusaka <apusaka@chromium.org>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Johan Hedberg <johan.hedberg@gmail.com>,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: [PATCH v1] Bluetooth: L2CAP: add support for waiting disconnection resp
Date: Tue, 14 Apr 2020 16:08:40 +0800 [thread overview]
Message-ID: <20200414160758.v1.1.Idab9dcdc7da549ed1fd5c66341fb8baffaee8d10@changeid> (raw)
From: Archie Pusaka <apusaka@chromium.org>
Whenever we disconnect a L2CAP connection, we would immediately
report a disconnection event (EPOLLHUP) to the upper layer, without
waiting for the response of the other device.
This patch offers an option to wait until we receive a disconnection
response before reporting disconnection event, by using the "how"
parameter in l2cap_sock_shutdown(). Therefore, upper layer can opt
to wait for disconnection response by shutdown(sock, SHUT_WR).
This can be used to enforce proper disconnection order in HID,
where the disconnection of the interrupt channel must be complete
before attempting to disconnect the control channel.
Signed-off-by: Archie Pusaka <apusaka@chromium.org>
---
net/bluetooth/l2cap_sock.c | 30 +++++++++++++++++++++++-------
1 file changed, 23 insertions(+), 7 deletions(-)
diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index 1cea42ee1e922..a995d2c51fa7f 100644
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -1271,14 +1271,21 @@ static int l2cap_sock_shutdown(struct socket *sock, int how)
struct l2cap_conn *conn;
int err = 0;
- BT_DBG("sock %p, sk %p", sock, sk);
+ BT_DBG("sock %p, sk %p, how %d", sock, sk, how);
+
+ /* 'how' parameter is mapped to sk_shutdown as follows:
+ * SHUT_RD (0) --> RCV_SHUTDOWN (1)
+ * SHUT_WR (1) --> SEND_SHUTDOWN (2)
+ * SHUT_RDWR (2) --> SHUTDOWN_MASK (3)
+ */
+ how++;
if (!sk)
return 0;
lock_sock(sk);
- if (sk->sk_shutdown)
+ if ((sk->sk_shutdown & how) == how)
goto shutdown_already;
BT_DBG("Handling sock shutdown");
@@ -1301,11 +1308,20 @@ static int l2cap_sock_shutdown(struct socket *sock, int how)
* has already been actioned to close the L2CAP
* link such as by l2cap_disconnection_req().
*/
- if (sk->sk_shutdown)
- goto has_shutdown;
+ if ((sk->sk_shutdown & how) == how)
+ goto shutdown_matched;
}
- sk->sk_shutdown = SHUTDOWN_MASK;
+ /* Try setting the RCV_SHUTDOWN bit, return early if SEND_SHUTDOWN
+ * is already set
+ */
+ if ((how & RCV_SHUTDOWN) && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
+ sk->sk_shutdown |= RCV_SHUTDOWN;
+ if ((sk->sk_shutdown & how) == how)
+ goto shutdown_matched;
+ }
+
+ sk->sk_shutdown |= SEND_SHUTDOWN;
release_sock(sk);
l2cap_chan_lock(chan);
@@ -1335,7 +1351,7 @@ static int l2cap_sock_shutdown(struct socket *sock, int how)
err = bt_sock_wait_state(sk, BT_CLOSED,
sk->sk_lingertime);
-has_shutdown:
+shutdown_matched:
l2cap_chan_put(chan);
sock_put(sk);
@@ -1363,7 +1379,7 @@ static int l2cap_sock_release(struct socket *sock)
bt_sock_unlink(&l2cap_sk_list, sk);
- err = l2cap_sock_shutdown(sock, 2);
+ err = l2cap_sock_shutdown(sock, SHUT_RDWR);
chan = l2cap_pi(sk)->chan;
l2cap_chan_hold(chan);
--
2.26.0.110.g2183baf09c-goog
next reply other threads:[~2020-04-14 8:09 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-14 8:08 Archie Pusaka [this message]
2020-04-20 2:49 ` [PATCH v1] Bluetooth: L2CAP: add support for waiting disconnection resp Archie Pusaka
2020-04-22 17:41 ` Marcel Holtmann
2020-04-23 10:15 ` Archie Pusaka
2020-05-13 8:04 ` Marcel Holtmann
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