From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755314AbcHSHi4 (ORCPT ); Fri, 19 Aug 2016 03:38:56 -0400 Received: from down.free-electrons.com ([37.187.137.238]:43867 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755200AbcHSHiw (ORCPT ); Fri, 19 Aug 2016 03:38:52 -0400 From: Boris Brezillon To: Marcel Holtmann , Gustavo Padovan , Johan Hedberg , linux-bluetooth@vger.kernel.org Cc: linux-kernel@vger.kernel.org, jason.abele@gmail.com, Boris Brezillon Subject: [PATCH 4/4] Bluetooth: hci_ldisc: make sure we don't loose HCI_UART_TX_WAKEUP events Date: Fri, 19 Aug 2016 09:38:47 +0200 Message-Id: <1471592327-14133-5-git-send-email-boris.brezillon@free-electrons.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1471592327-14133-1-git-send-email-boris.brezillon@free-electrons.com> References: <1471592327-14133-1-git-send-email-boris.brezillon@free-electrons.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The HCI_UART_TX_WAKEUP flag checking is racy and some HCI_UART_TX_WAKEUP events can be lost. Signed-off-by: Boris Brezillon --- 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