netdev - [PATCH 1/2] Bluetooth: Notify suspend on le conn failed

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Message-Id: <20210301120602.1.Ia32a022edc307a4cb0c93dc18d52b6c5f97db23b@changeid>
Date:   Mon,  1 Mar 2021 12:06:04 -0800
From:   Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
To:     marcel@...tmann.org
Cc:     chromeos-bluetooth-upstreaming@...omium.org,
        Hans de Goede <hdegoede@...hat.com>,
        linux-bluetooth@...r.kernel.org,
        Abhishek Pandit-Subedi <abhishekpandit@...omium.org>,
        Archie Pusaka <apusaka@...omium.org>,
        "David S. Miller" <davem@...emloft.net>,
        Johan Hedberg <johan.hedberg@...il.com>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        Jakub Kicinski <kuba@...nel.org>,
        Luiz Augusto von Dentz <luiz.dentz@...il.com>
Subject: [PATCH 1/2] Bluetooth: Notify suspend on le conn failed

When suspending, Bluetooth disconnects all connected peers devices. If
an LE connection is started but isn't completed, we will see an LE
Create Connection Cancel instead of an HCI disconnect. This just adds
a check to see if an LE cancel was the last disconnected device and wake
the suspend thread when that is the case.

Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
Reviewed-by: Archie Pusaka <apusaka@...omium.org>
---
Here is an HCI trace when the issue occurred.

< HCI Command: LE Create Connection (0x08|0x000d) plen 25                                           #187777 [hci0] 2021-02-03 21:42:35.130208
        Scan interval: 60.000 msec (0x0060)
        Scan window: 60.000 msec (0x0060)
        Filter policy: White list is not used (0x00)
        Peer address type: Random (0x01)
        Peer address: D9:DC:6B:61:EB:3A (Static)
        Own address type: Public (0x00)
        Min connection interval: 15.00 msec (0x000c)
        Max connection interval: 30.00 msec (0x0018)
        Connection latency: 20 (0x0014)
        Supervision timeout: 3000 msec (0x012c)
        Min connection length: 0.000 msec (0x0000)
        Max connection length: 0.000 msec (0x0000)
> HCI Event: Command Status (0x0f) plen 4                                                           #187778 [hci0] 2021-02-03 21:42:35.131184
      LE Create Connection (0x08|0x000d) ncmd 1
        Status: Success (0x00)
< HCI Command: LE Create Connection Cancel (0x08|0x000e) plen 0                                     #187805 [hci0] 2021-02-03 21:42:37.183336
> HCI Event: Command Complete (0x0e) plen 4                                                         #187806 [hci0] 2021-02-03 21:42:37.192394
      LE Create Connection Cancel (0x08|0x000e) ncmd 1
        Status: Success (0x00)
> HCI Event: LE Meta Event (0x3e) plen 19                                                           #187807 [hci0] 2021-02-03 21:42:37.193400
      LE Connection Complete (0x01)
        Status: Unknown Connection Identifier (0x02)
        Handle: 0
        Role: Master (0x00)
        Peer address type: Random (0x01)
        Peer address: D9:DC:6B:61:EB:3A (Static)
        Connection interval: 0.00 msec (0x0000)
        Connection latency: 0 (0x0000)
        Supervision timeout: 0 msec (0x0000)
        Master clock accuracy: 0x00
... <skip a few unrelated events>
@ MGMT Event: Controller Suspended (0x002d) plen 1                                                 {0x0002} [hci0] 2021-02-03 21:42:39.178780
        Suspend state: Controller running (failed to suspend) (0)
@ MGMT Event: Controller Suspended (0x002d) plen 1                                                 {0x0001} [hci0] 2021-02-03 21:42:39.178780
        Suspend state: Controller running (failed to suspend) (0)
... <actual suspended time>
< HCI Command: Set Event Filter (0x03|0x0005) plen 1                                                #187808 [hci0] 2021-02-04 09:23:07.313591
        Type: Clear All Filters (0x00)

 net/bluetooth/hci_conn.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index 6ffa89e3ba0a85..468d31f3303d7a 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -772,6 +772,16 @@ void hci_le_conn_failed(struct hci_conn *conn, u8 status)
 
 	hci_conn_del(conn);
 
+	/* The suspend notifier is waiting for all devices to disconnect and an
+	 * LE connect cancel will result in an hci_le_conn_failed. Once the last
+	 * connection is deleted, we should also wake the suspend queue to
+	 * complete suspend operations.
+	 */
+	if (list_empty(&hdev->conn_hash.list) &&
+	    test_and_clear_bit(SUSPEND_DISCONNECTING, hdev->suspend_tasks)) {
+		wake_up(&hdev->suspend_wait_q);
+	}
+
 	/* Since we may have temporarily stopped the background scanning in
 	 * favor of connection establishment, we should restart it.
 	 */
-- 
2.30.1.766.gb4fecdf3b7-goog