On 07/12/2013 04:40 PM, Gianluca Anzolin wrote:
Move the tty initialization from rfcomm_tty_open to rfcomm_tty_install and do
the same for the cleanup moving the code from rfcomm_tty_close to
rfcomm_tty_cleanup.
Signed-off-by: Gianluca Anzolin <gianluca@xxxxxxxxxxxxxx>
This should be patch 3/8.
Thus changes to rfcomm_tty_open()/rfcomm_tty_close() can rely on these
operations occurring. (see my comments in current patch 3/8)
---
net/bluetooth/rfcomm/tty.c | 82 +++++++++++++++++++++++++++-------------------
1 file changed, 49 insertions(+), 33 deletions(-)
diff --git a/net/bluetooth/rfcomm/tty.c b/net/bluetooth/rfcomm/tty.c
index 9b0b064..c1dd55d 100644
--- a/net/bluetooth/rfcomm/tty.c
+++ b/net/bluetooth/rfcomm/tty.c
@@ -717,10 +717,55 @@ static void rfcomm_dev_modem_status(struct rfcomm_dlc *dlc, u8 v24_sig)
}
/* ---- TTY functions ---- */
+/*
+ * here we acquire the tty_port reference since it's here the tty is first used
+ * by setting the termios. We also populate the driver_data field and install
+ * the tty_port.
+ */
+static int rfcomm_tty_install(struct tty_driver *driver, struct tty_struct *tty)
+{
+ struct rfcomm_dev *dev;
+ int err;
+
+ dev = rfcomm_dev_get(tty->index);
+ if (!dev)
+ return -ENODEV;
+
+ /* Attach TTY */
+ rfcomm_dlc_lock(dev->dlc);
+ tty->driver_data = dev;
+ rfcomm_dlc_unlock(dev->dlc);
+ set_bit(RFCOMM_TTY_ATTACHED, &dev->flags);
+
+ err = tty_port_install(&dev->port, driver, tty);
+ if (err < 0) {
+ clear_bit(RFCOMM_TTY_ATTACHED, &dev->flags);
+ tty_port_put(&dev->port);
+ }
+
+ return err;
+}
+
+/*
+ * here we do the reverse, by clearing the tty fields and releasing
+ * the reference to tty_port.
+ */
+static void rfcomm_tty_cleanup(struct tty_struct *tty)
+{
+ struct rfcomm_dev *dev = tty->driver_data;
+
+ /* Remove driver data */
+ clear_bit(RFCOMM_TTY_ATTACHED, &dev->flags);
+ rfcomm_dlc_lock(dev->dlc);
+ tty->driver_data = NULL;
+ rfcomm_dlc_unlock(dev->dlc);
+
+ tty_port_put(&dev->port);
+}
+
static int rfcomm_tty_open(struct tty_struct *tty, struct file *filp)
{
- struct rfcomm_dev *dev;
- struct rfcomm_dlc *dlc;
+ struct rfcomm_dev *dev = tty->driver_data;
unsigned long flags;
int id;
@@ -728,14 +773,6 @@ static int rfcomm_tty_open(struct tty_struct *tty, struct file *filp)
BT_DBG("tty %p id %d", tty, id);
- /* We don't leak this refcount. For reasons which are not entirely
- clear, the TTY layer will call our ->close() method even if the
- open fails. We decrease the refcount there, and decreasing it
- here too would cause breakage. */
- dev = rfcomm_dev_get(id);
- if (!dev)
- return -ENODEV;
-
BT_DBG("dev %p dst %pMR channel %d opened %d", dev, &dev->dst,
dev->channel, dev->port.count);
@@ -746,16 +783,6 @@ static int rfcomm_tty_open(struct tty_struct *tty, struct file *filp)
}
spin_unlock_irqrestore(&dev->port.lock, flags);
- dlc = dev->dlc;
-
- /* Attach TTY and open DLC */
-
- rfcomm_dlc_lock(dlc);
- tty->driver_data = dev;
- tty_port_tty_set(&dev->port, tty);
- rfcomm_dlc_unlock(dlc);
- set_bit(RFCOMM_TTY_ATTACHED, &dev->flags);
-
return 0;
}
@@ -764,9 +791,6 @@ static void rfcomm_tty_close(struct tty_struct *tty, struct file *filp)
struct rfcomm_dev *dev = (struct rfcomm_dev *) tty->driver_data;
unsigned long flags;
- if (!dev)
- return;
-
BT_DBG("tty %p dev %p dlc %p opened %d", tty, dev, dev->dlc,
dev->port.count);
@@ -774,14 +798,6 @@ static void rfcomm_tty_close(struct tty_struct *tty, struct file *filp)
if (!--dev->port.count) {
spin_unlock_irqrestore(&dev->port.lock, flags);
- /* detach the TTY */
- clear_bit(RFCOMM_TTY_ATTACHED, &dev->flags);
-
- rfcomm_dlc_lock(dev->dlc);
- tty->driver_data = NULL;
- tty_port_tty_set(&dev->port, NULL);
- rfcomm_dlc_unlock(dev->dlc);
-
if (test_bit(RFCOMM_TTY_RELEASED, &dev->flags)) {
spin_lock(&rfcomm_dev_lock);
list_del_init(&dev->list);
@@ -791,8 +807,6 @@ static void rfcomm_tty_close(struct tty_struct *tty, struct file *filp)
}
} else
spin_unlock_irqrestore(&dev->port.lock, flags);
-
- tty_port_put(&dev->port);
}
static int rfcomm_tty_write(struct tty_struct *tty, const unsigned char *buf, int count)
@@ -1165,6 +1179,8 @@ static const struct tty_operations rfcomm_ops = {
.wait_until_sent = rfcomm_tty_wait_until_sent,
.tiocmget = rfcomm_tty_tiocmget,
.tiocmset = rfcomm_tty_tiocmset,
+ .install = rfcomm_tty_install,
+ .cleanup = rfcomm_tty_cleanup,
};
int __init rfcomm_init_ttys(void)
--
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