Return-Path: From: Gianluca Anzolin To: gustavo@padovan.org Cc: peter@hurleysoftware.com, marcel@holtmann.org, linux-bluetooth@vger.kernel.org, gregkh@linuxfoundation.org, jslaby@suse.cz, stable@vger.kernel.org, Gianluca Anzolin Subject: [PATCH v2 3/4] rfcomm: always wait for a bt connection on open() Date: Mon, 6 Jan 2014 19:43:14 +0100 Message-Id: <1389033795-23895-4-git-send-email-gianluca@sottospazio.it> In-Reply-To: <1389033795-23895-1-git-send-email-gianluca@sottospazio.it> References: <1389033795-23895-1-git-send-email-gianluca@sottospazio.it> List-ID: This patch fixes two regressions introduced with the recent rfcomm tty rework. The current code uses the carrier_raised() method to wait for the bluetooth connection when a process opens the tty. However processes may open the port with the O_NONBLOCK flag or set the CLOCAL termios flag: in these cases the open() syscall returns immediately without waiting for the bluetooth connection to complete. This behaviour confuses userspace which expects an established bluetooth connection. The patch restores the old behaviour by waiting for the connection in rfcomm_dev_activate() and removes carrier_raised() from the tty_port ops. As a side effect the new code also fixes the case in which the rfcomm tty device is created with the flag RFCOMM_REUSE_DLC: the old code didn't call device_move() and ModemManager skipped the detection probe. Now device_move() is always called inside rfcomm_dev_activate(). Signed-off-by: Gianluca Anzolin Reported-by: Andrey Vihrov Reported-by: Beson Chow --- net/bluetooth/rfcomm/tty.c | 43 +++++++++++++++++++++++++++++++++++-------- 1 file changed, 35 insertions(+), 8 deletions(-) diff --git a/net/bluetooth/rfcomm/tty.c b/net/bluetooth/rfcomm/tty.c index 32ef9f9..65c0699 100644 --- a/net/bluetooth/rfcomm/tty.c +++ b/net/bluetooth/rfcomm/tty.c @@ -58,6 +58,7 @@ struct rfcomm_dev { uint modem_status; struct rfcomm_dlc *dlc; + wait_queue_head_t conn_wait; struct device *tty_dev; @@ -123,8 +124,37 @@ static struct device *rfcomm_get_device(struct rfcomm_dev *dev) static int rfcomm_dev_activate(struct tty_port *port, struct tty_struct *tty) { struct rfcomm_dev *dev = container_of(port, struct rfcomm_dev, port); + DEFINE_WAIT(wait); + int err; + + err = rfcomm_dlc_open(dev->dlc, &dev->src, &dev->dst, dev->channel); + if (err) + return err; + + while (1) { + prepare_to_wait(&dev->conn_wait, &wait, TASK_INTERRUPTIBLE); + + if (dev->dlc->state == BT_CLOSED) { + err = -dev->err; + break; + } else if (dev->dlc->state == BT_CONNECTED) + break; + else if (signal_pending(current)) { + err = -ERESTARTSYS; + break; + } + + tty_unlock(tty); + schedule(); + tty_lock(tty); + } + finish_wait(&dev->conn_wait, &wait); - return rfcomm_dlc_open(dev->dlc, &dev->src, &dev->dst, dev->channel); + if (!err) + device_move(dev->tty_dev, rfcomm_get_device(dev), + DPM_ORDER_DEV_AFTER_PARENT); + + return err; } /* we block the open until the dlc->state becomes BT_CONNECTED */ @@ -151,7 +181,6 @@ static const struct tty_port_operations rfcomm_port_ops = { .destruct = rfcomm_dev_destruct, .activate = rfcomm_dev_activate, .shutdown = rfcomm_dev_shutdown, - .carrier_raised = rfcomm_dev_carrier_raised, }; static struct rfcomm_dev *__rfcomm_dev_get(int id) @@ -258,6 +287,7 @@ static int rfcomm_dev_add(struct rfcomm_dev_req *req, struct rfcomm_dlc *dlc) tty_port_init(&dev->port); dev->port.ops = &rfcomm_port_ops; + init_waitqueue_head(&dev->conn_wait); skb_queue_head_init(&dev->pending); @@ -576,12 +606,9 @@ static void rfcomm_dev_state_change(struct rfcomm_dlc *dlc, int err) BT_DBG("dlc %p dev %p err %d", dlc, dev, err); dev->err = err; - if (dlc->state == BT_CONNECTED) { - device_move(dev->tty_dev, rfcomm_get_device(dev), - DPM_ORDER_DEV_AFTER_PARENT); + wake_up_interruptible(&dev->conn_wait); - wake_up_interruptible(&dev->port.open_wait); - } else if (dlc->state == BT_CLOSED) + if (dlc->state == BT_CLOSED) tty_port_tty_hangup(&dev->port, false); } @@ -1103,7 +1130,7 @@ int __init rfcomm_init_ttys(void) rfcomm_tty_driver->subtype = SERIAL_TYPE_NORMAL; rfcomm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV; rfcomm_tty_driver->init_termios = tty_std_termios; - rfcomm_tty_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL; + rfcomm_tty_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL; rfcomm_tty_driver->init_termios.c_lflag &= ~ICANON; tty_set_operations(rfcomm_tty_driver, &rfcomm_ops); -- 1.8.5.2