From: Abhishek Pandit-Subedi <abhishekpandit@xxxxxxxxxxxx>
Some drivers depend on shutdown being called for proper operation.
Unset HCI_USER_CHANNEL and call the full close routine since shutdown is
complementary to setup.
Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@xxxxxxxxxxxx>
---
Using hci_qca, we can get the controller into a bad state simply by
trying to bind to userchannel twice (open+bind+close, then open+bind).
Without running the shutdown routine, the device seems to get into a bad
state. A similar bug also occurs with btmtksdio (using MT7921).
This change properly runs the shutdown routine, which should be
complementary to setup. The reason it unsets the HCI_USER_CHANNEL flag
is that some drivers have complex operations in their shutdown routine
(including sending hci packets) and we need to support the normal data
path for them (including cmd_timeout + recovery mechanisms).
Note for v2: I've gotten a chance to test this on more devices
and figure out why it wasn't working before in v1. I found two problems:
I had a signal pending (SIGTERM) that was messing things up in the
socket release function and the HCI_USER_CHANNEL flag was preventing
hci_sync from operating properly during shutdown on Intel chipsets
(which use the sync functions to send a reset command + other commands
sometimes).
This was tested with hci_qca (QCA6174-A-3), btmtksdio (MT7921-SDIO)
and btusb (with AX200).
Changes in v3:
- Added hci_dev_shutdown to wrap disabling and re-enabling flag.
Changes in v2:
- Clear HCI_USER_CHANNEL flag at start of close and restore at end.
- Add comment explaning why we need to clear flag and run shutdown.
net/bluetooth/hci_sync.c | 33 ++++++++++++++++++++++++++-------
1 file changed, 26 insertions(+), 7 deletions(-)
diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index 422f7c6911d9..15c75ef4c271 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -4727,6 +4727,31 @@ static void hci_pend_le_actions_clear(struct hci_dev *hdev)
BT_DBG("All LE pending actions cleared");
}
+static int hci_dev_shutdown(struct hci_dev *hdev)
+{
+ int err = 0;
+ /* Similar to how we first do setup and then set the exclusive access
+ * bit for userspace, we must first unset userchannel and then clean up.
+ * Otherwise, the kernel can't properly use the hci channel to clean up
+ * the controller (some shutdown routines require sending additional
+ * commands to the controller for example).
+ */
+ bool was_userchannel =
+ hci_dev_test_and_clear_flag(hdev, HCI_USER_CHANNEL);
+
+ if (!hci_dev_test_flag(hdev, HCI_UNREGISTER) &&
+ test_bit(HCI_UP, &hdev->flags)) {
+ /* Execute vendor specific shutdown routine */
+ if (hdev->shutdown)
+ err = hdev->shutdown(hdev);
+ }
+
+ if (was_userchannel)
+ hci_dev_set_flag(hdev, HCI_USER_CHANNEL);
+
+ return err;
+}
+
int hci_dev_close_sync(struct hci_dev *hdev)
{
bool auto_off;
@@ -4746,13 +4771,7 @@ int hci_dev_close_sync(struct hci_dev *hdev)
hdev->adv_instance_timeout = 0;
}
- 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)
- err = hdev->shutdown(hdev);
- }
+ err = hci_dev_shutdown(hdev);
if (!test_and_clear_bit(HCI_UP, &hdev->flags)) {
cancel_delayed_work_sync(&hdev->cmd_timer);
--
2.38.0.rc1.362.ged0d419d3c-goog
