2022-09-27 20:27:48

by Abhishek Pandit-Subedi

[permalink] [raw]
Subject: [PATCH v3] Bluetooth: Call shutdown for HCI_USER_CHANNEL

From: Abhishek Pandit-Subedi <[email protected]>

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 <[email protected]>
---

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


2022-09-27 21:19:18

by bluez.test.bot

[permalink] [raw]
Subject: RE: [v3] Bluetooth: Call shutdown for HCI_USER_CHANNEL

This is automated email and please do not reply to this email!

Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=681203

---Test result---

Test Summary:
CheckPatch PASS 1.51 seconds
GitLint PASS 0.80 seconds
SubjectPrefix PASS 0.65 seconds
BuildKernel PASS 33.70 seconds
BuildKernel32 PASS 29.38 seconds
Incremental Build with patchesPASS 42.26 seconds
TestRunner: Setup PASS 498.42 seconds
TestRunner: l2cap-tester PASS 16.50 seconds
TestRunner: iso-tester PASS 15.38 seconds
TestRunner: bnep-tester PASS 6.09 seconds
TestRunner: mgmt-tester PASS 99.33 seconds
TestRunner: rfcomm-tester PASS 9.83 seconds
TestRunner: sco-tester PASS 9.19 seconds
TestRunner: ioctl-tester PASS 10.31 seconds
TestRunner: smp-tester PASS 9.30 seconds
TestRunner: userchan-tester PASS 6.28 seconds



---
Regards,
Linux Bluetooth

2022-09-28 21:56:32

by patchwork-bot+bluetooth

[permalink] [raw]
Subject: Re: [PATCH v3] Bluetooth: Call shutdown for HCI_USER_CHANNEL

Hello:

This patch was applied to bluetooth/bluetooth-next.git (master)
by Luiz Augusto von Dentz <[email protected]>:

On Tue, 27 Sep 2022 13:17:20 -0700 you wrote:
> From: Abhishek Pandit-Subedi <[email protected]>
>
> 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 <[email protected]>
>
> [...]

Here is the summary with links:
- [v3] Bluetooth: Call shutdown for HCI_USER_CHANNEL
https://git.kernel.org/bluetooth/bluetooth-next/c/8dbc3e75a0a5

You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html