linux-kernel - [PATCH 1/2] Bluetooth: Restore running state if suspend fails

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Message-Id: <20200319170708.1.I83970586f8340022b3909dccac1d79d191c6c70a@changeid>
Date:   Thu, 19 Mar 2020 17:07:12 -0700
From:   Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
To:     marcel@...tmann.org, linux-bluetooth@...r.kernel.org
Cc:     chromeos-bluetooth-upstreaming@...omium.org,
        Abhishek Pandit-Subedi <abhishekpandit@...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>
Subject: [PATCH 1/2] Bluetooth: Restore running state if suspend fails

If Bluetooth fails to enter the suspended state correctly, restore the
state to running (re-enabling scans). PM_POST_SUSPEND is only sent to
notifiers that successfully return from PM_PREPARE_SUSPEND notification
so we should recover gracefully if it fails.

Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
---

 net/bluetooth/hci_core.c | 39 ++++++++++++++++++++-------------------
 1 file changed, 20 insertions(+), 19 deletions(-)

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index dbd2ad3a26ed..2e7bc2da8371 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -3305,6 +3305,15 @@ static void hci_prepare_suspend(struct work_struct *work)
 	hci_dev_unlock(hdev);
 }
 
+static int hci_change_suspend_state(struct hci_dev *hdev,
+				    enum suspended_state next)
+{
+	hdev->suspend_state_next = next;
+	set_bit(SUSPEND_PREPARE_NOTIFIER, hdev->suspend_tasks);
+	queue_work(hdev->req_workqueue, &hdev->suspend_prepare);
+	return hci_suspend_wait_event(hdev);
+}
+
 static int hci_suspend_notifier(struct notifier_block *nb, unsigned long action,
 				void *data)
 {
@@ -3330,32 +3339,24 @@ static int hci_suspend_notifier(struct notifier_block *nb, unsigned long action,
 		 *    connectable (disabling scanning)
 		 *  - Second, program event filter/whitelist and enable scan
 		 */
-		hdev->suspend_state_next = BT_SUSPEND_DISCONNECT;
-		set_bit(SUSPEND_PREPARE_NOTIFIER, hdev->suspend_tasks);
-		queue_work(hdev->req_workqueue, &hdev->suspend_prepare);
-		ret = hci_suspend_wait_event(hdev);
+		ret = hci_change_suspend_state(hdev, BT_SUSPEND_DISCONNECT);
 
-		/* If the disconnect portion failed, don't attempt to complete
-		 * by configuring the whitelist. The suspend notifier will
-		 * follow a cancelled suspend with a PM_POST_SUSPEND
-		 * notification.
-		 */
-		if (!ret) {
-			hdev->suspend_state_next = BT_SUSPEND_COMPLETE;
-			set_bit(SUSPEND_PREPARE_NOTIFIER, hdev->suspend_tasks);
-			queue_work(hdev->req_workqueue, &hdev->suspend_prepare);
-			ret = hci_suspend_wait_event(hdev);
-		}
+		/* Only configure whitelist if disconnect succeeded */
+		if (!ret)
+			ret = hci_change_suspend_state(hdev,
+						       BT_SUSPEND_COMPLETE);
 	} else if (action == PM_POST_SUSPEND) {
-		hdev->suspend_state_next = BT_RUNNING;
-		set_bit(SUSPEND_PREPARE_NOTIFIER, hdev->suspend_tasks);
-		queue_work(hdev->req_workqueue, &hdev->suspend_prepare);
-		ret = hci_suspend_wait_event(hdev);
+		ret = hci_change_suspend_state(hdev, BT_RUNNING);
 	}
 
+	/* If suspend failed, restore it to running */
+	if (ret && action == PM_SUSPEND_PREPARE)
+		hci_change_suspend_state(hdev, BT_RUNNING);
+
 done:
 	return ret ? notifier_from_errno(-EBUSY) : NOTIFY_STOP;
 }
+
 /* Alloc HCI device */
 struct hci_dev *hci_alloc_dev(void)
 {
-- 
2.25.1.696.g5e7596f4ac-goog