Re: [PATCH v2 5/7] rfcomm: Remove the device from the dev_list in the destructor

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 07/22/2013 12:27 PM, Gianluca Anzolin wrote:
Remove the device from rfcomm_dev_list in the tty_port destructor.

Signed-off-by: Gianluca Anzolin <gianluca@xxxxxxxxxxxxxx>
---
  net/bluetooth/rfcomm/tty.c | 27 ++++++---------------------
  1 file changed, 6 insertions(+), 21 deletions(-)

diff --git a/net/bluetooth/rfcomm/tty.c b/net/bluetooth/rfcomm/tty.c
index 1258678..17e5faa 100644
--- a/net/bluetooth/rfcomm/tty.c
+++ b/net/bluetooth/rfcomm/tty.c
@@ -75,13 +75,6 @@ static void rfcomm_dev_modem_status(struct rfcomm_dlc *dlc, u8 v24_sig);

  /* ---- Device functions ---- */

-/*
- * The reason this isn't actually a race, as you no doubt have a little voice
- * screaming at you in your head, is that the refcount should never actually
- * reach zero unless the device has already been taken off the list, in
- * rfcomm_dev_del(). And if that's not true, we'll hit the BUG() in
- * rfcomm_dev_destruct() anyway.
- */
  static void rfcomm_dev_destruct(struct tty_port *port)
  {
  	struct rfcomm_dev *dev = container_of(port, struct rfcomm_dev, port);
@@ -89,10 +82,9 @@ static void rfcomm_dev_destruct(struct tty_port *port)

  	BT_DBG("dev %p dlc %p", dev, dlc);

-	/* Refcount should only hit zero when called from rfcomm_dev_del()
-	   which will have taken us off the list. Everything else are
-	   refcounting bugs. */
-	BUG_ON(!list_empty(&dev->list));
+	spin_lock(&rfcomm_dev_lock);
+	list_del(&dev->list);
+	spin_unlock(&rfcomm_dev_lock);

  	rfcomm_dlc_lock(dlc);
  	/* Detach DLC if it's owned by this dev */
@@ -295,7 +287,9 @@ out:
  			dev->id, NULL);
  	if (IS_ERR(dev->tty_dev)) {
  		err = PTR_ERR(dev->tty_dev);
+		spin_lock(&rfcomm_dev_lock);
  		list_del(&dev->list);
+		spin_unlock(&rfcomm_dev_lock);
  		goto free;
  	}

@@ -328,10 +322,6 @@ static void rfcomm_dev_del(struct rfcomm_dev *dev)
  	}
  	spin_unlock_irqrestore(&dev->port.lock, flags);

-	spin_lock(&rfcomm_dev_lock);
-	list_del_init(&dev->list);
-	spin_unlock(&rfcomm_dev_lock);
-
  	tty_port_put(&dev->port);
  }

@@ -753,13 +743,8 @@ static void rfcomm_tty_close(struct tty_struct *tty, struct file *filp)

  	tty_port_close(&dev->port, tty, filp);

-	if (test_bit(RFCOMM_TTY_RELEASED, &dev->flags)) {
-		spin_lock(&rfcomm_dev_lock);
-		list_del_init(&dev->list);
-		spin_unlock(&rfcomm_dev_lock);
-

Gianluca,

I think you may have missed my comment that this patch should
be earlier in the series. That way you wouldn't be adding code
in 4/7 that you're removing here.

Regards,
Peter Hurley


+	if (test_bit(RFCOMM_TTY_RELEASED, &dev->flags))
  		tty_port_put(&dev->port);
-	}
  }

  static int rfcomm_tty_write(struct tty_struct *tty, const unsigned char *buf, int count)


--
To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Bluez Devel]     [Linux Wireless Networking]     [Linux Wireless Personal Area Networking]     [Linux ATH6KL]     [Linux USB Devel]     [Linux Media Drivers]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [Big List of Linux Books]

  Powered by Linux