[PATCH] Bluetooth: Move shutdown callback before flushing tx and rx queue

From: Kai-Heng Feng
Date: Mon Aug 09 2021 - 13:47:36 EST


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@xxxxxxxxxxxx>
Tested-by: Hsin-Yi Wang <hsinyi@xxxxxxxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Fixes: 0ea9fd001a14 ("Bluetooth: Shutdown controller after workqueues are flushed or cancelled")
Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>
---
net/bluetooth/hci_core.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index cb2e9e513907..8da04c899197 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -1735,6 +1735,14 @@ int hci_dev_do_close(struct hci_dev *hdev)

hci_leds_update_powered(hdev, false);

+ 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);
+ }
+
/* Flush RX and TX works */
flush_work(&hdev->tx_work);
flush_work(&hdev->rx_work);
@@ -1798,14 +1806,6 @@ int hci_dev_do_close(struct hci_dev *hdev)
clear_bit(HCI_INIT, &hdev->flags);
}

- 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);
- }
-
/* flush cmd work */
flush_work(&hdev->cmd_work);

--
2.31.1