On Tue, 30 Aug 2016 09:53:53 -0700 Marcel Holtmann <[email protected]> wrote:
> Hi Boris, > > > The HCI_UART_TX_WAKEUP flag checking is racy and some HCI_UART_TX_WAKEUP > > events can be lost. > > > > Signed-off-by: Boris Brezillon <[email protected]> > > --- > > drivers/bluetooth/hci_ldisc.c | 11 +++++++++++ > > 1 file changed, 11 insertions(+) > > > > diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c > > index 27f73294edcb..ee7b25f1c6ce 100644 > > --- a/drivers/bluetooth/hci_ldisc.c > > +++ b/drivers/bluetooth/hci_ldisc.c > > @@ -172,6 +172,17 @@ restart: > > goto restart; > > > > clear_bit(HCI_UART_SENDING, &hu->tx_state); > > + > > + /* > > + * One last check to make sure hci_uart_tx_wakeup() did not set > > + * HCI_UART_TX_WAKEUP while we where clearing HCI_UART_SENDING. > > + * The work might have been scheduled by someone else in the > > + * meantime, in this case we return directly. > > + */ > > + if (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state) && > > + !test_and_set_bit(HCI_UART_SENDING, &hu->tx_state)) > > + goto restart; > > + > > I know this is correct, but I would actually make it visually different. > > if (test_bit(UART_TX_WAKEUP, ..) { > /* comment goes here > */ > if (!test_and_set_bit(UART_SENDING, ..) > goto restart; > } > > For me with a proper comment that is a lot easier to read and grok that it is > correct. Sure, I'll address that.
