tty: Fix double grabbing of a spinlock

The HSO changes for kref introduced a recursive spinlock take. All
functions which call put_rxbuf_data already have serial->serial_lock
grabbed.

[Comment to code added-AC]

Signed-off-by: Denis Joseph Barrow <D.Barrow@option.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/net/usb/hso.c b/drivers/net/usb/hso.c
index 9df04dd1332cf9b16b0d5998a1b03fb4083d6dc0..e25a58f6ff692a4bed4a46ce5efe087798e9e549 100644 (file)
--- a/drivers/net/usb/hso.c
+++ b/drivers/net/usb/hso.c
@@ -2044,9 +2044,8 @@ static int put_rxbuf_data(struct urb *urb, struct hso_serial *serial)
                return -2;
        }
 
-       spin_lock(&serial->serial_lock);
+       /* All callers to put_rxbuf_data hold serial_lock */
        tty = tty_kref_get(serial->tty);
-       spin_unlock(&serial->serial_lock);
 
        /* Push data to tty */
        if (tty) {