[PATCH 4/4] Bluetooth: hci_ldisc: make sure we don't loose HCI_UART_TX_WAKEUP events
flat view
STALE3700d
From: Boris Brezillon <hidden>
Date: 2016-08-19 07:38:56
Also in:
lkml
Subsystem:
bluetooth drivers, the rest · Maintainers:
Marcel Holtmann, Luiz Augusto von Dentz, Linus Torvalds
The HCI_UART_TX_WAKEUP flag checking is racy and some HCI_UART_TX_WAKEUP events can be lost. Signed-off-by: Boris Brezillon <redacted> --- 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; + } static void hci_uart_init_work(struct work_struct *work)
--
2.7.4