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.
Regards
Marcel
