linux-kernel - [PATCH 4.19 084/293] Bluetooth: Move shutdown callback before flushing tx and rx queue

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Message-Id: <20210920163936.142096944@linuxfoundation.org>
Date:   Mon, 20 Sep 2021 18:40:46 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Hsin-Yi Wang <hsinyi@...omium.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Kai-Heng Feng <kai.heng.feng@...onical.com>,
        Marcel Holtmann <marcel@...tmann.org>,
        Sasha Levin <sashal@...nel.org>,
        Mattijs Korpershoek <mkorpershoek@...libre.com>
Subject: [PATCH 4.19 084/293] Bluetooth: Move shutdown callback before flushing tx and rx queue

From: Kai-Heng Feng <kai.heng.feng@...onical.com>

[ Upstream commit 0ea53674d07fb6db2dd7a7ec2fdc85a12eb246c2 ]

Commit 0ea9fd001a14 ("Bluetooth: Shutdown controller after workqueues
are flushed or cancelled") introduced a regression that makes mtkbtsdio
driver stops working:
[   36.593956] Bluetooth: hci0: Firmware already downloaded
[   46.814613] Bluetooth: hci0: Execution of wmt command timed out
[   46.814619] Bluetooth: hci0: Failed to send wmt func ctrl (-110)

The shutdown callback depends on the result of hdev->rx_work, so we
should call it before flushing rx_work:
-> btmtksdio_shutdown()
 -> mtk_hci_wmt_sync()
  -> __hci_cmd_send()
   -> wait for BTMTKSDIO_TX_WAIT_VND_EVT gets cleared

-> btmtksdio_recv_event()
 -> hci_recv_frame()
  -> queue_work(hdev->workqueue, &hdev->rx_work)
   -> clears BTMTKSDIO_TX_WAIT_VND_EVT

So move the shutdown callback before flushing TX/RX queue to resolve the
issue.

Reported-and-tested-by: Mattijs Korpershoek <mkorpershoek@...libre.com>
Tested-by: Hsin-Yi Wang <hsinyi@...omium.org>
Cc: Guenter Roeck <linux@...ck-us.net>
Fixes: 0ea9fd001a14 ("Bluetooth: Shutdown controller after workqueues are flushed or cancelled")
Signed-off-by: Kai-Heng Feng <kai.heng.feng@...onical.com>
Signed-off-by: Marcel Holtmann <marcel@...tmann.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 net/bluetooth/hci_core.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 7a85f215da45..ec6150564f59 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -1622,6 +1622,14 @@ int hci_dev_do_close(struct hci_dev *hdev)
 	hci_request_cancel_all(hdev);
 	hci_req_sync_lock(hdev);
 
+	if (!hci_dev_test_flag(hdev, HCI_UNREGISTER) &&
+	    !hci_dev_test_flag(hdev, HCI_USER_CHANNEL) &&
+	    test_bit(HCI_UP, &hdev->flags)) {
+		/* Execute vendor specific shutdown routine */
+		if (hdev->shutdown)
+			hdev->shutdown(hdev);
+	}
+
 	if (!test_and_clear_bit(HCI_UP, &hdev->flags)) {
 		cancel_delayed_work_sync(&hdev->cmd_timer);
 		hci_req_sync_unlock(hdev);
-- 
2.30.2