[08/12] usb: serial: sierra: disable irq's for portdata lock

[08/12] usb: serial: sierra: disable irq's for portdata lock

[Johan Hovold]

On Sun, Jun 24, 2018 at 12:32:11AM +0200, Sebastian Andrzej Siewior wrote:
> From: John Ogness <john.ogness@linutronix.de>
> 
> The portdata spinlock can be taken in interrupt context (via
> sierra_outdat_callback()).
> Disable interrupts when taking the portdata spinlock.

Good catch!

As this fixes a potential deadlock, I've reworded the commit message and
added a Fixes and stable-CC tag.

But as no one appears to have hit this since it was introduced over four
years ago, I think this can go into -next along with the rest of the
series.

All patches now applied. Nice work!

Thanks,
Johan
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[08/12] usb: serial: sierra: disable irq's for portdata lock

[Sebastian Andrzej Siewior]

From: John Ogness <john.ogness@linutronix.de>

The portdata spinlock can be taken in interrupt context (via
sierra_outdat_callback()).
Disable interrupts when taking the portdata spinlock.

Cc: Johan Hovold <johan@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 drivers/usb/serial/sierra.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/serial/sierra.c b/drivers/usb/serial/sierra.c
index d189f953c891..55956a638f5b 100644
--- a/drivers/usb/serial/sierra.c
+++ b/drivers/usb/serial/sierra.c
@@ -770,9 +770,9 @@ static void sierra_close(struct usb_serial_port *port)
 		kfree(urb->transfer_buffer);
 		usb_free_urb(urb);
 		usb_autopm_put_interface_async(serial->interface);
-		spin_lock(&portdata->lock);
+		spin_lock_irq(&portdata->lock);
 		portdata->outstanding_urbs--;
-		spin_unlock(&portdata->lock);
+		spin_unlock_irq(&portdata->lock);
 	}
 
 	sierra_stop_rx_urbs(port);